International Scientific Conference Light and Photonics: Science and TechnologydedicatedtoInternational Year of Light and Light-based Technologies-2015

BOOK OF ABSTRACTS

22ndMay, 2015Alecu Russo Balti State University, Republic of MoldovaEditorial boardPavel TOPAL, Doctor Habilitat, University Professor, Dean of Faculty of Exact, Economic and Environment Sciences, Alecu Russo Bli State University, responsible editorVeaceslavURSACHI,Doctor Habilitat, University Professor, Academy of Sciences of MoldovaIgor EVTODIEV,Doctor Habilitat, Associated Professor, State University of MoldovaDumitru NEDELCU,PhD, University Professor, Gheorghe Asachi Technical University of Iai, President of ModTech Professional Association, Iai, RomniaSebastian POPESCU,PhD, Associated Professor, Alexandru Ioan Cuza University of Iai, RomniaIgor POSTOLACHI,PhD, Associated Professor, Vice-Rector, State University of TiraspolAlexandr OJEGOV, PhD, Alecu Russo Bli State University, technical editor

Organization committeeChairman:Pavel TOPAL, Doctor Habilitat, University Professor, Dean of Faculty of Exact, Economic and Environment Sciences, Alecu Russo Bli State UniversityMembers:VeaceslavURSACHI,Doctor Habilitat, University Professor, Academy of Sciences of MoldovaPetru GAIN,Doctor Habilitat, University Professor, State University of MoldovaValeriu ABRAMCIUC,PhD, Associated Professor, Alecu Russo BliState UniversityDumitru NEDELCU,PhD, University Professor, Gheorghe Asachi Technical University of Iai, President of ModTech Professional Association, Iai, RomniaSebastian POPESCU,PhD, Associated Professor, Alexandru Ioan Cuza University of Iai, RomniaIgor POSTOLACHI,PhD, Associated Professor, Vice-Rector, State University of Tiraspol

Scientific CommitteeChairman:Ion TIGHINEANU, Academician, Doctor Habilitat, University Professor, Senior Vice-President of the Academy of Sciences of MoldovaMembers:Valeriu CANER,Academician, Doctor Habilitat, University Professor, President of the National Accreditation and Certification Council, Republic of MoldovaIonel Valentin VLAD, Academician, University Professor, President of the Romanian AcademyPavel TOPAL, Doctor Habilitat, University Professor, Dean of Faculty of Exact, Economic and Environment Sciences, Alecu Russo Bli State UniversityDumitru LUCA,PhD, University Professor, Vice-Rector Alexandru Ioan Cuza University of Iai, RomniaTeodor MUNTEANU,Doctor Habilitat, University Professor, National Council for Accreditation and Attestation, Republic of MoldovaAnatolie SIDORENKO,Corresponding Member of the Academy of Sciences of Moldova, Doctor Habilitat, University Professor, Director of the Ghitu Institute of Electronic Engineering and Nanotechnologies, Republic of MoldovaVeaceslav PERJU,Doctor Habilitat, University Professor, vice president of the National Council of Accreditation and Attestation, Republic of MoldovaValerian DOROGAN,Doctor Habilitat, University Professor, Vice-Rector of the Technical University of MoldovaAla COJOCARU,Dr., Christian-Albrechts Universitaet, Kiel, GermaniaLaureniu SLTINEANU,PhD, University Professor, Gheorghe Asachi Technical University of Iai, RomniaDumitru NEDELCU,PhD, University Professor, Gheorghe Asachi Technical University of Iai, President of ModTech Professional Association, Iai, RomniaNiciolae SRBU,Doctor Habilitat, University Professor, Technical University of MoldovaMihail CARAMAN,Doctor Habilitat, University Professor, State University of MoldovaShavkatYULDASHEV,PhD, D. Sc., Dongguk University, South KoreaVolodymyr TSMOTS,Doctor Habilitat, University Professor, Drohobych Ivan Franko State Pedagogical University, UkraineC.MYNBAEV,Doctor Habilitat, Ioffe Institute, RussiaSveatoslav MOSCALENCO,Academician, Doctor Habilitat, University Professor, Institute of Applied Physics, Academy of Sciences of MoldovaLeonid CULIUC,Academician, Doctor Habilitat, University Professor, Institute of Applied Physics, Academy of Sciences of MoldovaRoman SCHRITTWIESER,PhD, University Professor, Institute for Ion Physics and Applied Physics, Innsbruck, AustriaEugen GHEORGHI,Doctor Habilitat, University Professor, State University of TiraspolVictor ONTEA,PhD, Associated Professor, Technical University of MoldovaIgor EVTODIEV,Doctor Habilitat, Associated Professor, State University of MoldovaMircea DRAGOMAN,PhD, University Professor, National Institute of Research and Development in Microtechnologies, Bucharest, RomniaDana DOROGOI,PhD, University Professor, Alexandru Ioan Cuza University of Iai, RomniaMihail CARAMAN,Doctor Habilitat, University Professor, State University of MoldovaNicolae SOBOLEV,Doctor Habilitat, University Professor,University of Aveiro, PortugalNicolae IONESCU, PhD, Associated Professor, "Politehnica" University of Bucharest, RomniaValeriu ABRAMCIUC,PhD, Associated Professor, Alecu Russo Bli State UniversityEugeniu PLOHOTNIUC, PhD, Associated Professor, Alecu Russo Bli State UniversityValeriu GUAN,PhD, Associated Professor, Alecu Russo Bli State UniversityMihail POPA,PhD, Associated Professor, Alecu Russo Bli State UniversityVitalie BELIU,PhD, Associated Professor, Alecu Russo Bli State UniversityIon OLARU,PhD, Associated Professor, Alecu Russo Bli State UniversitySilviu GURLUI,PhD, Associated Professor, Alexandru Ioan Cuza University of Iai, RomniaAndrzej WROBEL,Dr. Ing., Silesian University of Technology, Gliwice, PolandOlivera MILOSEVIC,Professor, Institute of Technical Sciences, Belgrade, President of Belgrade ModTech Branch, SerbiaRadhey Shyam BENIWAL, Dr., CSIR-NISCAIR, New Delhi, IndiaOctavian PRUTEANU,PhD, University Professor, Gheorghe Asachi Technical University of Iai, Vice-President of ModTech Professional Association, Iai, RomniaCorneliu MUNTEANU,PhD, University Professor, Gheorghe Asachi Technical University of Iai, RomniaEmil OANTA,PhD,University Professor, Vice-Rector, Maritime University of Constana, RomniaConstantin CARAUSU,Associated Professor, Gheorghe Asachi Technical University of Iai, RomniaViorel COHAL,Associated Professor, Gheorghe Asachi Technical University of Iai, RomniaAlexandar MAKEDONSKI,PhD, University Professor,Technical University of Sofia, Bulgaria

Sponsors

AGEPI, State Agency on Intellectual Property of the Republic of MoldovaRepublic of Moldova, Chisinau, Andrei Doga Str.,24/1Director: Lilia Bolocan

StarNet SRL, Republic of Moldova, Chisinau,Vlaicu Parcalab Str., 52

INCERCOM .S., Republic of Moldova, Chisinau,Independentei Str. 6/1Director: Anatolii Izbnda

Moldagrotehnica SA, Republic of Moldova, Balti, Industriala str., 4Director: Podureac Vasilii

Proiect Energetic SRL, Republic of Moldova, Balti, Conev Str., 52/28Director: Eduard Pulbere

Chiseliov Serghei Nicolai

ALAVITANORD SRL, Republic of Moldova, Balti, Traian Str., 6Director: Valerian Epure

Energetic SRLDirector: Carolina Babii

ModTech Professional Association,Blvd. Carol I, No. 28A, Bl.E4, Sc.B, Et.1, Ap.6, 700504, Iasi, RomaniaDirector: Dumitru NedelcuProgram SectionsPlenary Session / Invited SpeakersPolyvalent Room, Block no. 1Chairman: Pavel TOPAL, Doctor Habilitat, University Professor, Dean of Faculty of Exact, Economic and Environment Sciences, Alecu Russo Bli State UniversityIon TIGHINEANU, Academician, Doctor Habilitat, University Professor, Senior Vice-President of the Academy of Sciences of Moldova.

Convergence between electronic and light technologies or how electron and light work for humanity

Corneliu MUNTEANU,PhD, University Professor, Gheorghe Asachi Technical University of Iai, Romnia

Morphological aspects of zirconia coating on Ti-Zr alloy obtained with athmospheric plasma spraying technique

Dumitru LUCA,PhD, University Professor, Vice-Rector Alexandru Ioan Cuza University of Iai, Romnia

Light in Photo-catalysis. Todays facts - future challenges

Sections of the Conference1. Light and Photonics Science, Block no. 5, Room 533Chairman: VeaceslavURSACHI,Doctor Habilitat, University Professor, Academy of Sciences of Moldova2. Light and Photonics Technology, Block no. 5, Room 505Chairman: Anatolie SIDORENKO,Corresponding Member of the Academy of Sciences of Moldova, Doctor Habilitat, University Professor, Director of the Ghitu Institute of Electronic Engineering and Nanotechnologies, Republic of Moldova3. Light and Photonics Teaching, Block no. 5, Room 531Chairman: Igor EVTODIEV,Doctor Habilitat, Associated Professor, State University of Moldova

CZU: 621.315.592

Structural, Surface STUDIES AND optical properties of the CdSe thin films deposited by close space sublimation method

Duca D., Dobromir M., Nica V., Potlog T.

Influence of substrate temperature on the structural, composition and optical properties of deposited CdSe thin films are presented here. Thin films of CdSe were deposited on glass substrates covered with SnO2 by varying the substrate temperature in the interval (170-300)oC. The structural, composition and optical properties of the grown samples were investigated by XRD, XPS and UV-VIS spectrometry. The all as-deposited CdSe films shows polycrystalline nature and exhibit hexagonal crystallinity with (002) preferential orientation around 2=25.5. The lattice parameters, grain size, average internal stress, microstrain, dislocation density in the films were calculated. With the increase of the substrate temperature from 170oC to 250oC the crystallite size is increased from 34.66 nm to 44.97 nm respectively, but with further increase of the substrate to 300 C, the crystallite size in this direction decreases. Also, we determined elemental composition of CdSe films by X-ray photoelectron spectroscopy. The XPS spectra correspond to individual elements of the CdSe thin film. The strong peaks at 411.9 eV and 405.1 eV correspond to Cd3d3/2 and Cd3d5/2 binding energies. The peaks at 55.1 eV and 54.2 eV measured in the Se energy region is attributed to the Se3d3/2 and Se3d5/2 transitions, respectively. The small shift in the binding energy of Se from their standard values is due to the presence of adsorbed oxygen. The optical study shows that the CdSe thin films possess direct allowed transition. The band gap has been found around 1.71 eV for the CdSe films obtained at 170oC, 250oC and 300oC whereas the band gap of CdSe deposited at 220oC increase approximately to 1.72 eV.

CZU: 621.315.592

Morphology, Composition and Structural properties of the Cd1-xZnxS thin films

Cazac V., Duca D., Potlog T.

II-VI compound semiconductors with a variable band gap have interesting optical applications, such as solar cell, photodetector and laser. The Cd1-x Zn x S thin films has been prepared by the close space sublimation method using a mechanically alloyed mixture of CdS and ZnS. The morphology, composition and structural properties have been investigated through the SEM, EDX and X-ray analysis. SEM images indicated that the grains were increased after Zn diffusion in the Cd1-x Zn x S thin films occurs. The composition analysis made by the energy dispersive X-ray technique confirmed the presence of Zn in Cd1-x Zn x S thin films. The X-ray diffraction patterns of these films show that films are polycrystalline and revealed that the most intense peaks corresponded to cubic CdS and hexagonal ZnS phases. The preferential plane crystallization of ZnS phase was observed changing with increasing of the source temperature. At Tev = 700oC the preferred orientation of ZnS is [002], while for the Tev = 750oC preferred orientation becomes [110]. The crystallite size of CdS phase were about 20 nm, which was increased up to 25 nm after increasing Zn composition in Cd1-x Zn x S thin films. The EDX analysis indicated that Zn replaced Cd and the composition of Cd was decreased after Zn diffusion with a slight increase in S shown.

CZU: 621.375.826

Phonon cooling correlating dynamics

Crlig Sergiu

We investigated the unsteady-state cooling dynamics of vibrational quanta related to a nanomechanical oscillator coupled with a laser-pumped quantum dot in an optical resonator. Nanoresonator flexion modifies dots energy levels and for a set of parameters absorption of laser photon and nano-resonator phonon is followed by photon emission in cavity mode (Fig. 1). Such scheme of photon/phonon absorption/emission allows detection of nanoresonator cooling due to cavity photon emission.

Fig. 1. Studied model consisting from semiconductor beam with attached quantum dot suspended in optical cavity

CZU: 621.315.592

MICROSCOPY AND MOSSBAUER STUDIES OF IRON STATES IN DOPED GALIUM ANTIMONIDE Turt Constantin, Teodorescu Valentin Serban, Mihlache Alexei, Gheorghi Eugen, Volodina Galina, Filoti George

A single crystal of gallium antimonide doped with 3 at.% 57Fe was obtained via the Czochralski method. The Mssbauer investigations revealed four iron patterns - one diamagnetic and three Fe magnetically ordered sites, even at room temperature. The data suggested that iron containing compounds are formed at grain boundaries and the microscopy images revealed the presence of two types of boundaries and holes of different shape and size (Fig. 1, 2). The EDX spectrum provided different amounts of Fe in the crystal (GaSb) and, respectively, at the boundary area.

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Fig. 1. Optical image (in reflection) of axis the GaSb-Fe TEM specimenFig. 2. Domain oriented in zone of the cubic GaSb structure

CZU: 621.315.592

Morphological aspects of Zirconia coating on Ti-Zr alloy obtained with athmospheric plasma spraying technique

Istrate Bogdan, Barca Eduard Sebastian, Munteanu Corneliu

In recent years different types of titanium alloys have been investigated with the aim of utilizing materials in biomaterials field, and TiZr system alloys are very promising materials. In this paper, microstructure and morphology of ZrO2-CaO coating deposited on Ti-55Zr alloy is investigated. Zirconia ceramic coating was deposited using Sulzer Metco 9MCE atmospheric plasma spraying, in order to improve corrosion resistance and biocompatibility. Microstructure and phase analysis of based material and ceramic coating were investigated using scanning electron microscopy (Fig. 1, 2), X-ray diffractometry (XRD). The coated layer presents a homogenous aspect with an average thickness layer of 120 microns and some small cracks and splats.

Splats a) b) c) d)Fig. 1. SEM images of ZrO2-CaO cross-section coating

a) b)Fig. 2. EDAX analysis of cross-section coating

CZU: 621.315.592

QUANTUM PROPERTIES OF HIGH-FIELD GALVANOMAGNETIC EFFECTS IN TWISTING BICRYSTALS OF 3D TOPOLOGICAL INSULATOR Bi1-xSbx

Muntyanu M. Fiodor, Gilewski Andrzej, Chistol Vitalie, Rogacki Krzysztof

Magnetoresistance and Hall effects in twisting bicrystals of 3D topological insulator Bi1-xSbx were studied in magnetic fields up to 40 T. For bicrystals with large crystallite disorientation angle, oscillations of the galvanomagnetic effects were observed revealing that in quasi 2D crystallite interfaces the density of states is higher and the charge carriers are heavier than in bulk. Our results show that in twisting bicrystals of 3D topological insulator different quantum electronic states can be induced and controlled by the crystallite disorientation angle and magnetic field.

CZU: 621.315.592

MORPHOLOGICAL AND X-RAY DIFFRACTION ANALYSIS OF CH3NH3PbI3 PEROVSKITE SEMICONDUCTOR

Plesco Irina, Ghimpu Lidia, Ciobanu Vladimir, Volodina Galina, TighineanuIon

This kind of material is considered very promising for use in photovoltaics. Large family of perovskites include insulating, antiferromagnetic, piezoelectric, thermoelectric, superconductive, conductive and semiconductive materials. Semiconductive perovskites used in photovoltaics have some precious advantages as processability from solutions on the room temperature, low price, tunability of optical and electrical properties by chemical methods, also color tunability. Therefore initial study of this material has includedRntgenfaze analysis. Was observed that on perovskite concentration of 40% with 1:1 rate of PbI2:CH3NH3I just a part of lead-iodide has reacted and it wasnt completely compensated. Results of proper investigations were compared with published results of international research groups.

CZU: 621.375.826

QUANTUM DYNAMICS OF ACOUSTICAL PHONON STATISTICS

Ceban Victor, Macovei A. Mihai

We present a model of the quantum control via a laser light of the phonon statistics of an acoustical field and of the population inversion of a qubit. The phonon field is created in an acoustical multilayered nanocavity with a single-mode field being selected and it interacts with the thermal environment as well as with a qubit embedded in the cavity. The considered qubit is made of a quantum dot (QD). The confinement of the acoustical fields' quantum statistics is possible via driving the QD with an intense laser light, which for a proper detuning from the QD's transition frequency and for a well-chosen intensity may lead to sub-Poissonian distributed steady-state phonon fields (Fig. 1). Furthermore, we show that for higher damping rates phonon assisted QD's population inversion occurs under the action of the created phonon fields with quantum statistics.

Fig. 1. The second-order correlation function (continuous curve), the mean phonon number (dotted curve) and the QDs population inversion (dashed curve) as functions of the lasers detuning :(a) For a low damping regime with and (b) for a high damping regime with . The vertical axis are representing, from left to right: , and . The other models parameters are: , , .

CZU: 621.315.592

INVESTIGATION OF OPTICAL PROPERTIES OF ZnSxSe1-x THIN FILMS

Popa Mihail

ZnSxSe1-x thin films (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) were prepared from thermal evaporation technique in quasi closed volume with a thickness between 0.2 and 1.0 m. Transmission, reflection and absorption spectrums of polycrystalline ZnSxSe1-x thin films have been studied. It has been discovered that in wavelength range 380 - 1100 nm reflection coefficient does not exceed 0.5% and the transmission coefficient is between 75-97%. This tells us that ZnSxSe1-x thin films are transparent and absorption of electromagnetic waves in these layers is also relatively small. The values of optical band gap determined from date of reflection and absorbtion spectra (Eg = 2.68 3.5eV) are in a good agreement with the values of band gap energy obtained for bulk crystals. From the transmission spectra, using the "envelope" method proposed by Swanepoel, was determined the refractive index of the polycrystalline ZnSxSe1-x thin films. It decreases with increasing of thickness and increasing after the heat treatment. For the explication of the normal dispersion of the refractive index has been used a single oscillator model.

CZU: 621.315.592

THE STUDY OF PHOTOCONDUCTIVITY AND LUMINESCENCE PROPERTIES OF ZnSxSe1-x THIN FILMS

Popa Mihail

ZnSxSe1-x thin films were prepared from vacuum evaporated technique on the glass substrates using powders of ZnS and ZnSe. Structural analysis, surface morphology and composition of thin films had been perfected from XRD, SEM and EDAX technique. Diffraction patterns determined that ZnSxSe1-x thin films have a cubic structure of zinc blende type, with a strong orientation of the crystallite after the crystalline plane (111). The composition analysis revealed that films were nearly stoichiometric. Relaxation curves of the photoconductivity of ZnSxSe1-x thin films were studied for different temperature. It notes that the stationary photoconductivity st decreases with increasing of sample temperature. This is explained by the fact that at higher temperatures the concentration of charge carriers is greater balance and this is why increases of recombination probability (R ). From the relaxation curves of photoconductivity and photoluminescence of ZnSxSe1-x thin films was calculated lifetime () of nonequilibrium charge carriers. Value of relaxation time decreases with increasing sample temperature. Level location energy of recombination centers was determined from photoluminescence spectral dependence and catch levels ionization energy values were calculated from thermoluminescence spectral dependence of ZnSxSe1-x thin films.

CZU: 543.3:502.5(204)

EXPERIMENTAL INVESTIGATION OF SOME PHYSICAL AND CHEMICAL FEATURES OF WATER QUALITY

Luchian Efimia

Since water is one of the most important elements in human life and activity, its quality investigation and insurance plays a very important role. The conductivity, pH, temperature and dissolved oxygen (DO2) are very important physico-chemical indices in water quality assessing. This work aim is to exemplify these parameters measurements and water quality control. Fig. 1. Water Quality MultiMeasure Sensor with PASPORT interface.The analysis of drinking water physical and chemical properties was performed on a group of samples of different trademarks of bottled water found on Moldovan market. The analyzed physical and chemical characteristic indexes are conductivity, pH and dissolved oxygen (DO2) in water. These indexes were investigated with Water Quality MultiMeasure Sensor PS-2169 equipped with electrodes specific for each type of measurement (Figure 1). For data acquisition the sensor is connected to computer via the device SPARK Science Learning System. The conductivity component sensor measures the electrolytic conductivity of aqueous solutions. It determines the conductivity by applying an alternating voltage to the electrode cell at the end of the probe and measuring the resulting current. The pH electrode produces a voltage proportional to the pH of the solution that it is immersed in. This voltage is measured by the multi-sensor, which computes pH. The DO2 probe consists of a platinum (Pt) cathode and a silver (Ag) anode surrounded by potassium chloride (KCl(aq)) electrolyte filling solution with a silicon membrane separating the filling solution from the test solution. When the probe is placed in an aqueous medium that contains dissolved oxygen, O2 molecules diffuse across the membrane and react with water molecules (H2O) in the presence of electrons from the cathode to form hydroxide ions (OH-). Hydroxide ions diffuse to the anode and react with silver atoms, forming silver oxide (Ag2O), H2O, and free electrons. The net movement of negative charge (electrons) from the cathode to the anode is measured by the sensor as an electric current. Since the rate of O2 diffusion across the membrane is proportional DO2 concentration, the rate of these reactions and the resulting electric current is also proportional to DO2 concentration.

Fig. 2. The conductivity dependence of temperatureAs a result of the performed experiments it was found that the impurity level is higher only in one sample, whose conductivity exceeds the maximum amount indicated in Normative Documents (2500 S/cm). Conductivity value for the other sampleswas within the allowable limits. After investigation of conductivity temperature dependence it was found that it increases linearly with temperature increase (Figure 2). The pH value was within stipulated limits (6.5 9.5) for all samples, taking values of 8.32 8.96. Thus, we can say that analyzed water is alkaline. Dissolved oxygen values were also within normal limits, the highest concentration was recorded for sample no. 4 (18.5 mg / l) and the lowest (10.0 mg / l) for sample no. 2.CZU: 621.371.33

INVESTIGATIONS IN THE FIELD OF INTERFERENCE AND DIFFRACTION OF LIGHT

Deleu Gabriela, Evtodiev Igor

Using the principles of interference and diffraction of light, in the lab are investigated possibilities of one digital lab, to determine the linear dimensions of the objects with reduced dimensions in general and in particular use the graphical method is proposed for determining the distance between two slits which are in parallel at very small a distance in a device.Digital lab includes Data collection system ; Rotary motion sensor ; High sensitivity light sensor; Sensor extension cable; Linear Translator; Optics bench, 1.2-m1; Red diode laser ( = 632 nm); Precision Diffraction Slits; Aperture Bracket. In Figure 1 is presented pattern from red light passing through a narrow slit. In the pattern are very clear areas of higher and lower intensity which are the result of very conditional constructive and destructive interference between waves of light.

Figure 1 Red laser diffraction pattern through a single slitWhen more than one slit is present, the diffraction pattern produced by each slit will interfere with other patterns from other slits. With two very narrow slits separated by a distance d, the interference pattern consists of many additional areas of bright and dark fringes compared to those from a single slit diffraction pattern (figure 2); however, it is still very clear that diffraction is occurring as you can see the distinct areas of higher and lower intensity that match those from a single-slit diffraction pattern.

Figure 2 Red laser interference and diffraction pattern through two slitsKnowing the wavelength of the laser radiation, measuring the distance from the slits to the screen system and interference fringes respective corresponding angle relative to the main peak was calculated distance between slots is equal to d = 53.2 m.

CZU: 621.373.1

THE EXPERIMENTAL STUDY OF IDEAL AND REAL HARMONIC OSCILLATORS

Koss Alexander, Evtodiev Igor

The following research was dedicated to studying and experimenting with harmonic oscillators of all kinds. The equipment used was a portable computer, the PASCO Spark, a force sensor, 3 different springs and weights. The portable computer is responsible for storing the data received from the force sensor, and constructing a ForceTime graph. The force sensor has a range of 50 N, an accuracy of 0.1 N and a recording speed of up to 1000 Hz. It is also equipped with a reset button to automatically set it to 0 N. The springs used in the experiment differed in damping. The first spring had a very low damping coefficient, so after the weight was released they continued oscillating for a very long time, fading away only very slightly. The second spring had a medium damping coefficient, so the time it took for the oscillations to fade was much shorter, then with the first spring. The third spring however had a very high damping coefficient, so the oscillations only continued for about 6 seconds.The experiment itself was performed by hanging a weight on the spring, and starting the data recording as soon as the weight is dropped. In all 3 experiments the data was recorded at a frequency of 100 Hz. Afterwards, the computer built Force-Time graphs for every experiment. This allowed us to visualize the difference between the 3 springs. The computer used in the experiment has a very useful ability of generating functions for graphs. This can be done in order to study ideal harmonic oscillations. A Sine Fit graph can be generated precisely from the data using average values. On the image below is illustrated the graph received from the 3rd spring with a high damping coefficient and the function assigned to it. The function generated from the graph continues forever, and can be used for further research in the field of beats, which are automatically calculated and simulated by the computer. Thanks to the precise data recording equipment human errors can be minimized, which leads to very little inaccuracies in calculations.

CZU: 535.34:621.373

EMISSION SPECTRA FOR ANALYSING ELEMENTS IN CLUES USING OPTICAL METHODS

Koss Alexander, Evtodiev Silvia

The following research was dedicated to the investigation of emission spectra of different elements and their utilization in the analysis of clues. The equipment used was a spectrometer, the Red Tide USB-650, and an application called Overture. The spectrometer has a spectral range from 350 nm to 1000 nm. Its a very lightweight and portable device, not taking up much space and weighting only 190 g. The sensitivity of the device is 75 photons at a wavelength of 400 nm. The optical resolution of the spectrometer is 2 nm, while the program can display accurate graphs with a resolution of up to 0.1 nm. The spectrometers integration time ranges from 3 ms to up to 65 seconds, but typically it doesnt exceed 15 seconds. For very precise data recording the spectrometer can also be used using optic fibers. The program used has a library of emission spectra of different elements.The experiment is performed by making the substance emit photons by exciting it. The light from this substance are received by the spectroscope and data is transmitted to the computer. The program generates an Intensity-Wavelength graph right away. But to analyze and detect elements in clues a graph is not the only required thing. Luckily, we have access to the emission spectra library built into the program. Those can be enabled and disabled to detect if the given element is present in the earlier analyzed substance. Here is an example of what it looks like: on the following image is the data received from pointing the spectrometer at a mercury lamp and activating the mercury emission spectrum in the library.The peaking lines are the emission spectra of mercury. Their presence indicates that mercury is present in the substance. Such a method can be used to detect elements in clues using spectral methods at remarkable speeds and accuracies.

CZU: 535.34:621.373

ROLE OF OPTICAL RADIATION IN DIGITIZED MEASUREMENTS

Bulhac Daniela, Evtodiev Silvia, Evtodiev Igor

Fig. 1 The emission spectrum of hot body W at 2250 K.Fig. 2 Emission spectrum of a gas discharge tubeIn this work is studied the role of optical radiation in digital linear metrology measurements, that develops both experimental and theoretical determinations at any level of uncertainty in the application applied science and technology expertise. Chemical and physical measurements provide digitization, information processing and display it in graphical, numerical and tabular. To enhance the quality of experimental tests, we use digital measuring instruments. This work investigates the optical sensor for movement characterization (S.O.M) that allows reading position, velocity and acceleration furnished with a frequency up to 49 kHz. S.O.M has a SPARK system, which expressly favors while reading and collecting experimental data both in the laboratory building, as well as mobile. As an object of study were investigated laws of motion of a harmonic oscillator and interpretation of experimental results were performed by the analytical determination of functions which describes the laws of motion. For each measurement, the transducer transmits ultrasonic pulses 16 package. This package of pulses, creates a echo sound which is heard as a single click. The package of ultrasonic pulses are reflected from the surface of the investigated object, then are returning to the sensor. Target indicator flashes on the sensor optical when encoder detects the echo, and the sound intensity decreases with increasing distance. Thanks of optical methods were investigated samples with submicron size (0,350 1,100 m) using digital spectrometer. Complementary spectrometer was used for raising absorption spectra, transmission and reflection of pre-selected samples as a subject and conducted research in atomic spectroscopy, emission and absorption. In the Figure 1 is shown the spectrum of radiation emitted by hot bodies (T = 2250K, W filament, in a incandescent condition). For comparison in the Figure 2, is represented the emission spectrum of the optical radiation of the tube with mercury vapor gas discharge. On the background of the continuous spectrum of FL, ZnS substance is observed discrete emission spectra of atoms of mercury.

CZU: 621.371.31

THE INFLUENCE OF SOLVENT NATURE ON THE ELECTRONIC ABSORPTION SPECTRA OF SOME ORGANIC COMPOUNDS Gritco (Todirascu) Antonina, Morosanu Cezarina, Creanga Dorina-Emilia

The study of solvent influence on the molecular electronic spectra (Fig. 1) of biologically active compounds is crucial for the explanation of chemical and physical properties of studied compounds, in establishing of solute-solvent interaction nature, in obtaining information on the nature of energetic transitions underlying the generation of electronic spectral bands as well as for the understanding of reaction mechanisms. The main purpose of this study was the application of spectral method for revealing the rifampicin (Fig. 2) interaction ability with various organic solvents. From the accomplished study it was found that to the increase of the solvent refractive index the red shift also increased, as proof of the dominancy of dispersive interactions in the rifampicin diluted solutions.

Fig. 1. Optical radiation spectrum

Fig. 2. Rifampicin chemical structure

CZU: 535.2

Light in nanoscience: measuring the nanoparticles

Brinza Florin, Tascu Sorin, Olaru Ion

Increasing the importance and studyes regarding nanoparticle application and characterization has demanded new methods for their measurements. Particle size and orientative shape is the first goal in nanoparticle production. Paper describe two light-based methods frequently used in nanoparticle size measurement: dynamic light scattering DLS, and nanoparticle tracking analysis NTA, comparing performances, advantages and limits of each method. One of these methods can be easily implemented in nanoparticles characterization laboratory.

References1. Dynamic Light Scattering: An Introduction. Malvern LTD Technical note, 2010.2. Bob Carr, Patrick Hole, Andrew Malloy, Philip Nelson, MatthewWright, Jonathan Smith, Applications of nanoparticle tracking analysis in nanoparticle research amini review. European Journal of Parenteral & Pharmaceutical Sciences 2009; 14(2): 45-50.

CZU: 621.371.35

ABOUT A POSSIBLE DEVIATION FROM THE GEOSTROPHIC OF THE IONOSPHERIC WIND IN THE TWILIGHT

Abramciuc Valeriu

In this article is presented the research results of dynamic processes in the upper layers of Earth's atmosphere, the ionosphere E region. It is proposed and developed the concept of the possibility of deviation from geostrophic of the ionospheric wind in the twilight conditions. They made arguments in support of this hypothesis, given that the local deviation of the ionospheric wind from geostrophic is determined by the specific terms and conditions, which are established in the upper atmosphere during the transition from night to day or vice versa.During the study of dynamic processes in the upper layers of the earth's atmosphere, it is usually assumed that the air flow occurs horizontally, is linear and uniform, in the absence of friction forces. This situation is typical for the conditions in which there are only two forces balance one another - the pressure gradient and the Coriolis force - thus a large-scale atmospheric circulation has quasi-geostrophic character - a gradient of pressure force virtually offset by the Coriolis force. This implies that global motion of general circulation is sufficiently close to geostrophic wind, i. e. is slightly curvilinear, little susceptible to friction and associated with the distribution of pressure so that is oriented almost along isobars (perpendicular to the pressure gradient). It follows the zonal orientation of the general circulation in the atmosphere.In region E of the ionosphere, in twilight conditions, the friction layers are formed, and therefore, currents are substantially different from the geostrophic wind and deviate significantly from the isobars. Above friction layers also is violated the geostrophic airflow.The paper presents some consequences of deviations from geostrophic of ionospheric wind during periods of twilight. It is analyzed an important consequence - the emergence of zones of intense turbulence environment, which contributes to the formation of plasma irregularities.

CZU: 535.34:621.373

THE USE OF THE OPTICAL METHOD IN REGISTRATION OF TEMPERATURE PULSATIONS AT SAMPLES INTENDED FOR THE STUDY OF THERMAL PARAMETERS OF METALS AT HIGH TEMPERATURES

Bancila Simion

In this paper the study of entire complex of thermal properties (thermal diffusivity, heat capacity and thermal conductivity) is based on the method of temperature radial waves. The sample supposed to research takes the form of cylindrical wells filled with liquid metal and is made of two tantalum tubes. Cavity surface was subjected to a periodic warming in the form of realized by the vacuum electron bombardment. The outer surface temperature variation was recorded by the optical method (depending on the brightness oscillations).In the case of imposition of system geometry, thermal diffusivity was determined based on the characteristic time established through comparing the curves of periodic variation of temperature and heating power. When determining thermal capacity and thermal conductivity we used the processed information on mentioned above curves, but taking into account the absolute variation of the power and temperature.

CZU: 621.371:537.86

LIGHT ABSORPTION IN INDIVIDUAL INORGANIC MICRO PARTICLES DEPOSITED ON OPTICAL TRANSPARENT SUPPORT AND SUSPENDED IN OPTICAL HOMOGENOUS LIQUID

Evtodiev Silvia

In this work were studied the indicatrix of monochromatic radiation scattering with 623,8 nm wavelength from quartz and germanium nanoparticles and the diffuse light scattering spectra from these particles, in 400-700 nm spectral range. As diffusion etalon a BaF2 bulk was used.

CZU: 621.315.592

PHOTOLUMINESCENCE OF GaSe SINGLE CRYSTALS INTERCALATED BY Cd FROM SOLUTION

Dmitroglo Liliana

The photoluminescence of lamellar GaSe single crystals obtained by vapor phase and electrolythic intercalation from aqueous solution of CdCl2 was studied. By heat treatment at 753 K and 853 K of GaSe single crystal plates in Cd vapors during from 10 min to 24 hrs a new material, composed from CdSe and GaSe crystallites with the average dimensions of 34 nm and 30 nm respectively, was obtained. As a result of Cd atoms interaction with Se atoms the CdSe layers are formed on the external surface as well at Se-Ga-Ga-Se packing external surface. Cd2++ ions electrochemically intercalated do not modify of the cristaline structure of the lamellar nanocomposite. CdSe crystallites on the surface are growing in the form of plates in the direction of C6 crystallographic axis. The photoluminescence PL spectrum of the obtained from Cd vapors compoite at the temperatures of 78 K and 300 K contains dominant bands of the luminescence emission spectrum of GaSe and CdSe composite components but the PL spectrum of the composite obtained from H2O-CdCl2 solution contains the non-phononic emission bands of the indirect non-excited excitons and of the indirect localized excitons.

CZU: 621.315.592

ELECTRICAL INSTABILITY IN GaSe NANOLAMELLAR STRUCTURES INTERCALATED FROM CdCl2 SOLUTION

Spoiala Dorin

Recent years have seen increasing interest in analysis of the incorporation of metals, organic complexes, and hydrogen into layered IIIV semiconductors in connection with the need for crystals with tailored properties for various practical applications (power engineering, sensors, electronics and optoelectronics). One of the most viable approaches to controlling the properties of GaSe layered single crystals is electrochemical intercalation (incorporation): targeted incorporation of foreign ions, atoms, and molecules into interlayer spaces. This approach can be used to produce GaSe intercalation compounds with reproducible parameters and tune their electrical and photo electrical properties using intercalationdeintercalation processes. [1]. In this work, we report the results of our researches concerning the electrical properties of GaSe single crystals intercalated from CdCl2 solution. One of the faces of the crystal is brought into contact with the electrolyte and held therein for 1300 hours. During this time the kinetics of the change in resistance R and cyclic current-voltage I-U characteristics in 6 geometry were measured. Sudden step changes of the resistance encountered during the entire time of exposure of the sample in the electrolyte. At the same time it appears as step growth, and resistance reduction steps. The minimum value Rmin=36.0 was observed after 1060 hours of exposure, while the initial resistance decreased to 4336 times. In the process of intercalation a radical change of the I-U characteristics were observed. First, we note the appearance of regions with N- and S-types negative differential conductivity which was manifested at both polarities of the external bias voltage (Fig.1, a). Secondly, attention is drawn to existence on I-U curves of the broad current hysteresis at increasing and decreasing of applied voltage. Thirdly, on all I-U curves were observed current instabilities, which appear as sharp chaotic current changes at a slight change of applied voltage (Fig.1, a, b).(a)(b)

Fig.1. I-U curves obtained at various times keeping the sample in the CdCl2 electrolyte: a 312.5 hours, b 456.5 hours.

However, the greatest scientific and practical interest represents the memristor effect detected in this study (Fig.1, b). Memristive devices are promising components for nanoelectronics with applications in nonvolatile memory and storage, defect-tolerant circuitry, and neuromorphic computing [2]. The analyses of experimental data are performed. The possible mechanisms of the negative differential conductivity and memristor effect manifested in the intercalated samples are discussed.[1] V.Boledzyuk, et all. Inorganic Materials, 2013, Vol. 49, No. 1, pp. 2227.[2] M.D.Pickett, et all. Journal of Applied Physics, 2009, 106, 074508.CZU: 621.315.592

PHOTOLUMINESCENCE OF NANOLAMELAR STRUCTURES WITH METAL DOTS OBTAINED BY GaS MONOCRYSTAL INTERCALATION

Rotaru Irina

In this work are studied photoluminescence (PL) spectra from GaS crystals and GaS crystals intercalated with Cd atoms. Metal atoms were intercalated by 6 hours heat tratament at the temperature of 750K in metal vapor atmosphere. Gallium dots are created on external surface and between S-Ga-Ga-S packages. This dots are aranged as distorted hexagons. PL spectra of Cd intercalated crystals containes one simple contour band at 293K, and two bands at 78K. Band with maximum at 2,424 eV has a complex structure, composed by phonon repeats of indirect excitons emission.

CZU: 621.315.592

Distribution of Ga Impurity in Crystals Grown by Zone sublimation

Nikorich Valentina, Ketrush Petru, Nikorich Andrei

Study of the electronic properties of the narrow-gap PbTe, doped with different impurities, is stimulated by extensive use of AIVBVI semiconductors and their alloys in optoelectronics for manufacturing IR-lasers and detectors for the wavelength range extending from 1 to 40 m. The results of the investigations of charge flow phenomena in Ga doped lead chalcogenides(NGa= 0,5at. % ) during the growth process by zone sublimation are presented in the given paper. The studied samplesunlike of undoped PbTe crystals had the n-type electrical conductivity. The grown crystal length was of 5-6 cm, at this the electron concentration varied in the limits from2,71019m-3( the initial segment) to6,41018m-3(the final segment).In the sample with NGa= 0,5 at. % the electrons concentration practically does not depend on temperature (i.e. the pinning of the Fermi level is observed). The crystals were subjected to thermal treating(at 5400 and 6500) with the intermediate investigation of galvano-magnetic properties. The annealing at 5400 decreases the charge carriers concentration by 2-3 orders of magnitude and allows to decrease the electron concentration to 1,41016m-3and to increases their mobility to 3.104m2/Vs. (at 80). The annealing at 6500 changes electrical conductivity type from n- to p-type and decreases the holes mobility (up to ~ 9000 cm2/Vs), as the charge carriers concentration practically reaches the same values as at the annealing at 5400.

CZU: 621.315.592

Eu3+ IONS PHOTOLUMINESCENCE IN Cd INTERCALATED GaSe NANNOLAMELLAR STRUCTURES

Untila Dumitru

In this work were studied the crystalline structure and photoluminescence (PL) at 78K of the composite obtained by Cd intercalation of GaSe:Eu single crystalline lamella, at 753K temperature. The studied composite consist of microstructured CdSe and GaSe, and Eu3+ centers. The PL specter of Eu doped GaSe single crystalline lamella intercalated with Cd is composed from Eu3+ ion emission bands in GaSe (transitions 5D07F0,2,4, 5D17F2, 5D27F6), emission band of indirect excitons in GaSe crystallites and emission band of CdSe crystallites from compound.

CZU: 621.371.35

THE DAY-NIGHT TERMINATOR AND DISTURBANCES INDUCED IN THE IONOSPHERE

Abramciuc Valeriu

The paper presents research results of the disturbances that are generated in the terrestrial ionosphere due to the movement of the solar terminator. It was found that in the terminator region occur substantial changes of parameters characteristic of the atmosphere, ionosphere and magnetosphere. The mutual interaction of these regions is achieved through several mechanisms, briefly analyzed in the paper.Analysis of experimental data revealed that the interaction of conjugated magnetic regions is carried by means of Alfven waves.

CZU: 621.315.592

FABRICATION OF TIO2 NANOTUBULAR MEMBRANES OPENED FROM BOTH ENDS BY ELECTROCHEMICAL ANODIZATION TECHNIQUE

Ciobanu Vladimir, Enachi Mihail, Postolache Vitalie, Tighineanu Ion

Titanium dioxide is one of the most studied materials nowadays. TiO2 nanotubulare membranes find their applications in solar energy conversion, in hydrogen sensing, in catalysis for decomposition of organic materials, in biomedical applications, etc.In this paper we propose an electrochemical cost-effective method for obtaining both-ends opened nanotubulare membranes. The method implies several stages: a first anodization step for a short period of time followed by removal of the formed oxide, a second anodization for growing the membrane, and a final stage of detaching the membrane from the metal surface.By choosing the appropriate parameters for each stage, one can obtain nanotubulare membrane with large surface and identical nanotube sizes.

CZU: 621.771.06

DEVELOPMENT OF PETRI-NET CONTROL MODELS FOR RECONFIGURABLE MILLING MACHINES

Stambolov Grigor, Petkova P.

In modern automated manufacturing essential is the study of various processes and systems is carried not through direct research of real objects or systems, designed by their models. The mathematical instruments of Petri nets are power tool, which can to be useful for the modeling and analysis of several classes of systems, including not only computer systems and software, but and communication networks and production/process control systems in modern manufacturing. In this paper the Petri-Net control models and specially they modification Signal-Interpreted Petri Nets (SIPN) models are used for development of control applications of the reconfigurable manufacturing machines on the level technological operations and structured in library of knowledge.

CZU: 621.771.06EFFECT OF THE COMBINED ELECTROPHYSICAL PROCESSING OF PROCESS DEPENDENT VARIABLES DURING THE MILLING OF D2 STEEL

Makedonski Aleksandar, Makedonski Boris, Vilek Igor

The article presents the results from the application of a new method for raising the exploitation characteristics of metal-cutting tools, which includes preliminary combined magnetic field and ultrasound processing of the instrument. The indirect effect of the processing on the cutting force as well as on the roughness of the processed surface and on the wearing of the instruments during the milling process has been studied. It has been established that the resultant cutting force has been reduced, the roughness characteristics have been increased and the level of wearing of the instrument has been reduced, which is due to the occurring alterations in the friction conditions in the zone of chip formation.

CZU: 621.95.02

DRILLING OF THE RECIRCULATION HOLES OF ROLLER CARRIAGES

Stoev Lachezar, Popov Todor

In this publication the research results during the drilling of the recirculation holes of roller carriages are presented with two different types of drilling tools. The aim of the performed comparative experiments is the effect of cutting data while drilling and influence of specific geometric parameters of the tools in the prescribed dimensions, shape accuracy and the roughness the recirculation holes of the roller carriage determine.

CZU: 621.37:615.849

COLOR IN ALTERNATIVE THERAPY

Benchea Andreea Celia, Babusca Daniela, Morariu Magdalena

Colors are perceived by our eyes in all possible shades and intensities, and they affect our entire body. Chromo therapy is a natural method of treatment that uses the properties of colored light to produce favorable reactions to restore health. The Bioptron lamp system is a medical device for therapy with light, which acts by supporting the regenerative capacity and balancing the body and helps the body to activate its own healing potential. A performed statistical calculation demonstrates the color efficiency in health (Fig. 1, 2).

Fig. 1. Evolution of burns before and after application of the therapy

Fig. 2. Dermatological Status (Lichen Planus) before and after therapy

CZU: 621.375.826

EXtreme Light infrastructure Nuclear physics (ELI-NP) Project AND RESEARCH Program

Negoi Florin

An overview of ELI-NP facility under construction and the parameters of its two main machines, the High-Power Laser System (HPLS) and the Gamma Beam System (GBS), are presented along with the broad fundamental and applied research program they will enable (Fig. 1). More details are given for the high-power laser driven nuclear physics experiments and the instrumentation required by them.

Fig. 1. The 3D model of high-power laser experimental rooms and associated equipment

CZU: 621.371.3

REGULATION OF RADIATION TRANSMITTANCE THROUGH ELECTRO-OPTIC TECHNOLOGIES

Calancea Laureniu, Vizitiv Gleb, Evtodiev Igor

There are three fundamental mode of heat transfer: diffusion, convection and radiation. Although our modern windows are really good at blocking heat transferred from diffusion and convection, a lot of energy is able to pass through them in the form of electro-magnetic waves, mostly in the visible and infrared spectrum. It has been proven that even transparent curtains will afford adequate protection from optical radiation in the ultraviolet region, but that all of them will transmit high percentages of infrared radiation, while the solar irradiance is high in the infrared spectrum. Using a system of polarizers active specifically for the range of the IR spectrum with the highest irradiance, and a LCC we can alter the energy transmittance of windows without blocking visible light. This way, using fewer energy than usual conditioning systems we can control the temperature of the environment, without rendering our windows opaque in the visible spectrum. This is achieved by using a system of combined Kerr and Pockels cells, with high electro-optic constant, low energy expenses and longitudinal applied voltage.

CZU: 621.9.048.4

THERMOGRAVIMETRIC AND ELECTRONIC MICROSCOPIC SEM ANALYSES FOR GRAPHITE PELLICLES FORMED BY IMPULSE ELECTRIC DISCHARGES PROCEDURES

Marin Laurentiu, Topala Pavel, Marin Catalina Daniela, Ojegov Alexandr

A set of metallic with 25 x 25x 2 mm dimensions samples were subjected to an impulse electric discharges procedure. For the surface electric treatment of the metallic samples a graphite electrode cathode were used. On the surface of the metallic samples a thin pellicle of graphite was covered. This thin pellicle was subjected to a set of thermogravimetric analyses and electronic microscopic analyses SEM. The thermogravimetric analyses of the pellicle brought to light an interesting mass addition of the pellicle at some temperature points. The electronic microscopic SEM analyses uncovered another interesting phenomenon: on the graphite pellicle a lot of globular cluster structures are found.

CZU: 621.9.048.4

POLYURETHANE MATRIX NANOCOMPOSITES USED TO OBTAIN ANTI-SLIP, ANTI-WEAR AND FIRE-RESISTANT FLOORS FOR PUBLIC INSTITUTIONS, CIVIL AND INDUSTRIAL BUILDINGS

Marin Laurentiu, Topala Pavel, Marin Catalina Daniela, Sandu Teodor

Research and development activities presented were aimed at obtaining a nanocomposite polyurethane matrix with special anti-wear, anti-slip and fire-resistant properties. Research and development works were materialized by obtaining polyurethane nanocomposite matrix, by its physico-chemical modification in order to give the desired technological properties and by characterization of the obtained material. Polyurethane nanocomposite matrix was obtained by reacting a PETOL 3 type polyetherpolyol (having a molecular weight of 5000 UAM) with a diisocyanate under well-established reaction conditions. Target specific technological properties were obtained by physical and chemical modification of polyurethane nanocomposite matrix. The final result was getting a pellicle material based on modified nanocomposite polyurethane, with anti-wear, anti-slip and fire-resistant properties, compatible with most substrates encountered in civil and industrial construction: wood, concrete, metal.

CZU: 621.9.048.4

EXPERIMENTAL RESEARCH ON SURFACE MICRO-GEOMETRY MODIFICATION OF TUNGSTEN WIRES

Guzgan Dorin

The present paper is devoted to experimental investigations concerning the processing of conductive surfaces by applying pulse electrical discharge machining. We have particularly focused on the modifications of tungsten surface micro-geometry leading to the formation of Taylor cone shaped asperities (Fig. 1). We have established and presented the optimal energetic regimes of extracting cylindrical meniscuses from wires of 0.2 mm diameter. This paper also presents SEM images of obtained surface micro-geometry (Fig. 2).

Fig. 1. Conical meniscuses extracted from tungsten wire surface

Fig. 2. SEM image of a Taylor cone shaped asperity

CZU: 533.9.07

FORMATION OF ELECTRICAL DISCHARGE PLASMA AT LABORATORY CONDITIONS APPLYING ELECTRODES OF SPECIAL CONSTRUCTIONHirbu ArefaTo obtain the electrical discharge plasma under laboratory conditions we used the electrical scheme consisting of a special electrode with separate discharge channels that limit the current and the second plate-shaped electrode made of metal. Each separate channel of special electrode is a wire having a diameter of 0.35 mm. The free end of the electrode presents a set of edges (the ends of the channels), which leads to the increase of the intensity of electric field and to the increase of the autoionisation process of the active gas medium (the air from the gap). For a supply voltage of 25 kV and the distance between the electrodes of 7 mm, considering the 1.5 times increase of electric field intensity, the electric field intensity constitutes 6 MV/m. In the case when using special construction for the second electrode too (separate channels having a diameter of 5 times bigger and a length of 10 times lower than that of the first electrode) it permitsto increase the gap (and, respectively, the intensity of the electric field) up to 2 times. This construction of the electrodes leads to greater autoionisation efficiency and plasma of this type of discharges is more homogeneous. The energy that is released in a volume unit of gas from the gap decreases, but the quality of electrical discharge plasma increases, which has a priority over the scheme when we used the special electrode and the second of flat surface, on the other side the auto-excitement of the active media is more effective.

CZU: 621.9.048.4

ABOUT CORROSION OF THE GRAPHITE FILMS REALIZED BY ELECTRICAL DISCHARGES IN IMPULSE AT SUB-EXCITATION REGIME

Besliu Vitalie, Topala Pavel, Stoicev Petru, Ojegov Alexandr, Scutari Alexandru

Metal pieces and constructions make up one of the most expensive funds of the industry of any developed country, and their corrosion protection has become an important issue because of the emergence of the high economic expenses. Graphite films produced by electrical discharges in impulse at sub-excitation regime increase the surface layer hardness, durability and refractory properties of processed pieces, reduce the phenomenon of galling in the cinematic couples and possess anti-adhesive properties. But the influence of different aggressive media on these films has been very little studied. Experimental research shows that these films are quite resistant under the influence of different media. For example, after the retention of samples in the atmosphere over a period of about 3 years it was evident observed that the steel samples covered with graphite films didnt change in comparison with the unprocessed samples where is clearly seen the traces of corrosion (Figure 1). This could be explained by the fact that at electrical discharge machining with graphite tool-electrode connected as cathode on the anode surface we obtain not only graphite films of 7-10 micrometers, but oxide films too which is proved by EDX analyzes which showed an amount of oxygen at the surface of about 16-20%. It has also been established experimentally that in 30% HNO3 solution the larger corroded mass is observed for unprocessed by graphite tool-electrode steel in comparison with the samples coated with graphite films by about 1.4 times for 3 min and by about 1.3 times for 10 min. In 1% NaCl solution the speed of corrosion for unprocessed samples is of 1.2-1.4 times higher than for samples processed by electrical discharges in impulse.

a b cFig. 1. General view of the samples subject to corrosion in the atmosphere, under laboratory conditions, for 3 years: a original state; b surface without deposition; c surface with graphite filmsCZU: 621.9.048.4

METHODS FOR INTENSIFICATION OF ELECTRO-SPARK ALLOYING PROCESS

Pereteatcu Pavel, Cracan Cornel

This paper makes a bibliographical reference to the problems that refer to remove the deficiencies in the process of coatings deposition at electro-spark alloying (ESA). It is about the influence of different conditions during the surface layer formation on cathode such as the discharge energy, structure and phase transformations that occur in the superficial layers under the action of the spark discharge, the properties of obtained coatings, the influence of the gap media, the influence of the nature of electrode materials, the influence of movement kinematics of the processing electrode.In addition, the paper has also information about finishing operations surface hardening by the plastic deformation in order to improve the properties of coatings, and also about ESA alternating with vacuum annealing and ultrasonic polishing, smoothing through sparkling with graphite electrode, as well as smoothing through laser ray.In terms of perspective of ASE intensification by the action of external energy sources, the paper presents the results of the action by continuous and pulsed electric current on the process of formation of coatings, as well as the action of the magnetic field superimposed on the processing zone.The obtained results confirm the possibility of intensification of superficial layers formation under the action of these two energy sources: electric current and magnetic field.

CZU: 533.9.07

SECONDARY LIGHT RADIATION OBTAINED BY THE ACTION OF PLASMA

Topala Pavel, Hirbu Arefa, Ojegov Alexandr

The paper analyzes the possibility of obtaining the secondary radiation in red, yellow, green and violet at excitation of glass corps with different chemical composition. It was experimentally established that under the action of electrical discharge plasma some of the doping components of the filter glass pass on higher levels of excitement and radiates above mentioned visible light spectra. This new property can be applied in the construction of an inexpensive laser class. In Fig. 1 the above-mentioned experimentally obtained radiation spectra are shown.

a)b)c)

Fig. 1. Graphs of transparency and secondary radiation produced by the action of electrical discharge plasma for glass of type:a) UFS-2; b)TS-3 and ESAB SHADE 12; c) IKS-7CZU: 621.9.048.4

EXPERIMENTAL RESEARCH ON THE BEHAVIOR OF THE TOOL-ELECTRODES MADE OF CONDUCTIVE MATERIALS BY APPLYING EDM

Pinzaru Natalia

The paper presents results of experimental research on the construction and behavior of the tool-electrodes made of copper, brass, aluminum and graphite by applying electrical discharge machining (EDM). The electrodes applied at the formation of the surface layers were made of conductive materials and were subjected to various energy regimes during the experimental investigations (Fig. 1). We studied the effects arising between base electrodes (anode and cathode) varying polarity and voltage of the ccondencer battery, other regimes preserving the constants (gap, frequency of the impulses, capacity and duration).

Fig.1. Work scheme of deposit layers formation by EDM

CZU: 621.9.048.4

FORMATION THIN OXIDE FILMS ON SEMICONDUCTOR SURFACES BY APPLYING EDM

Topala Pavel, Rusnac Vladislav, Melnic Vasilii, Guzgan Dorin

As a result of the processing semiconductor surfaces by applying electrical discharge machining (EDM) the formation of oxide thin films is observed on its surface. Their appearance is explained by the interaction of plasma channel with the machined surface.The morphology of semiconductor surfaces of samples oxidized by the application of EDM is shown in Fig. 1,a.In general, during the processing of silicon surfaces, there can be formed two types of oxides: silicon monoxide (SiO) and silicon dioxide (SiO2), possessing insulating, protection, passivation, optical, etc. properties in semiconductor devices. Simultaneously with the formation of oxide films the formation of different types of clusters can be also observed (Fig. 1,b).

Fig. 1. Morfology of silicon samples surface after oxidation by applying EDM

CZU: 621.9.048.4

OBTAINING WEAR RESISTANT DEPOSITION LAYERS BY APPLYING EDM

Topala Pavel, Stoicev Petru, Balandin Anton

The paper presents information on obtaining deposition layers of metal powder on steel 35 surfaces by applying electrical discharge machining (EDM). Optimal energy regimes for deposit formation process are also presented. We carried out experimental research on determination of mechanical wear of the obtained surfaces (Fig. 1) and compared them with the results for the unprocessed surfaces.

a b cFig. 1. The workpiece surface coated with: a) TiC; b) BrA7; c) MoC

CZU: 519.2(072.8)

NUMERICAL CHARACTERISTICS AND STATISTICAL LEGITIMATE IN RELIABILITY THEORY Evtodiev Silvia, Velecu Dorina, Evtodiev Igor

This article refers to numerical characteristics of reliability features and reliability distribution functions after statistical regularities of reliability theory. I studied in more detail the Gamma Law and Weibull Law with 1, 2 and 3 parameters. Reliability of a system expresses its safety in operation. It is a function of time R (t), defined as the probability that the specified environmental conditions, the system may work properly, maintaining defaults in time interval [0, t). Reliability has a value between 0 and 1 and is a quality aspect. Reliability in terms of quality is the ability of a system to properly accomplish the functions envisaged for a period of time in specified operating conditions.There is a difference between reliability and quality. Reliability unlike quality is checking for product quality during its life. Reliability in quantitative terms is the probability that the system will perform its system functions correctly during a given time period in specified operating conditions. In more complex systems, knowing the reliability of each component can be calculated the reliability of the entire system.The development of reliability theory has positively influenced areas such as electronics, telecommunications, navigation systems, power system, tracked and guided computer systems, military equipment, etc.Using Microsoft Office Excel 2007 program I introduced the numerical values of the time t and pre-established defaults. Then I calculated using formulas the reliability function R (T); the unreliability function F (T); the distribution density f (T) and the failure hazard function h (T). Then I built graphs of data based on results.Since only average value knowledge offers no differentiation between technical systems, it is necessary to know other numerical characteristics of reliability. Thus, knowing the distribution function of the failures f (t) we can determine any numerical characteristic of reliability, including the average time for good service, dispersion, the standard deviation, the warranty time and reliability functions, unreliability and failure hazard.Analyzing these two laws in I noticed that their distribution is different, but common is that the reliability decreases in time, and unreliability increase in time. If the dispersion is lower, than the technical system reliability is higher. Originally we need to find the distribution function of the failures and established distribution law and then located reliability and its numerical characteristics.CZU: 53(072.3)

LIGHT AND COLOURS IN HUMAN ACTIVITIES

Dorohoi Dana Ortansa, Tudose Adina Elena, Ursu Oana, Dmitrascu Irina

The results in scholar activities at physics hours in three high schools from Vaslui and Iasi districts show that the colour nuances influence the nervous system and the individual mental state. In the experiments organized using light green screens and black pencils or yellow screens and green pencils the grades were higher (Fig. 1).

Fig. 1. Number of students vs. Obtained grades in experiments I, II, III

CZU: 53(072.3)

INTERDISCIPLINARY TEACHING OF A LIGHT-BASED BIOLOGICAL PROCESS: PHOTOSYNTHESIS

Brinza Cristina Carmen

The interdisciplinary study of light propagation and interaction with different environments can be performed to Physics classes and also in related disciplines such as Science discipline classes. The interdisciplinary approach ask the teacher to have knowledge of both specialized disciplines and related fields, very well mastered, to observe and explain complex phenomena of nature that lends itself to such studies.

References1. I. Andronic, M. Frunz, V. Duciac, Unele aspecte fizice ale fotosintezei, Fizica i tehnologiile moderne, vol 5, nr.1-2, 2007.2. A. Ardelean, A. X. Lupea Biochimie - Fotosinteza, Reglajul hormonal, informaia genetic vol II., Editura Academiei Romne, Bucureti, 2007.

CZU: 537(072.8)

NANOTECHNOLOGY. BEHIND THE EDGE OF VISIBLE WORLD

Topala Pavel, Botnari Dmitri

The global actual stage of development in the material science and production requires new materials with new properties. This is based on continuous and impetuous science and technical progress. The performance of electronics, medicine, building materials has reached a new edge of elaborations at microscopic level, nanotechnology. It is explained in accordance with society needs, resolving problems insight the world.The nanotechnology represents an area of dimensions contained within limits of 1 to 100 nm. One nanometer is equal to 10-9 meters. For understanding, the DNA double spiral radius is approximately 1nm, and the hydrogen atom diameter is equal to 0,1nm.Obtaining of nano-surfaces, nano-structures and nano-particles can be executed by using of concentrated energy sources. In particular, in scope of nano-particles obtaining, the actual study shows that the most used technology is explosion at high speed that destruct the electrode material and sprays particles in medium. It's explained in fact that particles are discarded to periphery in result of explosion and they don't have time to coagulate in "big" particle agglomerates. But then is present another problem to collect particles. In case of polarizing in contact to medium they can combine with anything.The following work will be based on obtaining of nano-particles and their collection.

CZU: 621.9.048(072.3)

DETERMINATION OF MATERIALS MARK BY ELECTRICAL DISCHARGE METHOD

Poperecini Anatolie

The present paper describes a method of determination of the mark of metals and alloys using electrical discharges. Form and emission spectrum of electrical discharges depends on technological and physico-chemical properties of studied material.This method has the next priorities:- includes all materials;- hasnt essential influence on the control sample;- is a quick method of determination;- allows to determine the mark of the piece material without further preparation;- the possibility of using this method for very small surfaces;- has high energy efficiency;- is more precise than abrasive method.Determination of the materials mark supposed to control by electrical discharges method is more accurate and does not require complicated setup and qualified personnel.

Author Index

A

Abramciuc Valeriu, 26, 34

B

Babusca Daniela, 39Balandin Anton, 51Bancila Simion, 27Barca Eduard Sebastian, 13Benchea Andreea Celia, 39Besliu Vitalie, 46Botnari Dmitri, 55Brinza Cristina Carmen, 54Brinza Florin, 25Bulhac Daniela, 23

C

Calancea Laureniu, 41Cazac V., 10Crlig Sergiu, 11Ceban Victor, 16Chistol Vitalie, 14Ciobanu Vladimir, 15, 35Cracan Cornel, 47Creanga Dorina-Emilia, 24

D

Deleu Gabriela, 20Dmitrascu Irina, 53Dmitroglo Liliana, 29Dobromir M., 9Dorohoi Dana Ortansa, 53Duca D., 9, 10

E

Enachi Mihail, 35Evtodiev Igor, 20, 21, 23, 41, 52Evtodiev Silvia, 22, 23, 28, 52

F

Filoti George, 12

G

Gheorghi Eugen, 12Ghimpu Lidia, 15Gilewski Andrzej, 14Gritco (Todirascu) Antonina, 24Guzgan Dorin, 44, 50

H

Hirbu Arefa, 45, 48

I

Istrate Bogdan, 13

K

Ketrush Petru, 32Koss Alexander, 21, 22

L

Luca Dumitru, 7Luchian Efimia, 19

M

Macovei A. Mihai, 16Makedonski Aleksandar, 37Makedonski Boris, 37Marin Catalina Daniela, 42, 43Marin Laurentiu, 42, 43Melnic Vasilii, 50Mihlache Alexei, 12Morariu Magdalena, 39Morosanu Cezarina, 24Munteanu Corneliu, 7, 13Muntyanu M. Fiodor, 14

N

Negoi Florin, 40Nica V., 9Nikorich Andrei, 32Nikorich Valentina, 32

O

Ojegov Alexandr, 42, 46, 48Olaru Ion, 25

P

Pereteatcu Pavel, 47Petkova P., 36Pinzaru Natalia, 49Plesco Irina, 15Popa Mihail, 17, 18Poperecini Anatolie, 56Popov Todor, 38Postolache Vitalie, 35Potlog T., 9, 10

R

Rogacki Krzysztof, 14Rotaru Irina, 31Rusnac Vladislav, 50

S

Sandu Teodor , 43Scutari Alexandru, 46Spoiala Dorin, 30Stambolov Grigor, 36Stoev Lachezar, 38Stoicev Petru, 46, 51

T

Tascu Sorin, 25Teodorescu Valentin Serban, 12Tighineanu Ion, 7, 15, 35Topala Pavel, 42, 43, 46, 48, 50, 51, 55Tudose Adina Elena, 53Turt Constantin, 12

U

Untila Dumitru, 33Ursu Oana, 53

V

Velecu Dorina, 52Vilek Igor, 37Vizitiv Gleb, 41Volodina Galina, 12, 15