Raster Electron Research Articles

Применение метода независимых каналов для определения электрической проводимости графеносодержащего шунгита.

The independent channel method which is intended for the calculation of specific electrical conductivity of graphene-contained shungite is proposed and realized on practice. It is noted that the most important of shungite application is the creation of screen hawing large area which are able to block electromagnetic radiation in wide frequency range. The most important factor which determines the blocking properties of shungite is the specific electrical conductivity of its carbon part which is determined by the spatial distribution of carbon atoms. As a main method of carbon structure investigation is mentioned the high-resolution raster electron microscopy which allows from the surface of specimen to receive the card of distribution of graphene slides and graphene packets. The spatial factor which determines the shungite conductivity is large anisotropy of single graphene slide which reaches three orders and more in the cases along and across the slide. The proposed method independent channels takes into consideration the arbitrary orientation of graphene packets relatively to direction of current flow. As a basis of method is employing the card of carbon spatial distribution which is received by raster electron microscopy method. The card is divided by parallel channels which transverse dimension is near or slightly exceeds the typical dimension of graphene packet. The channels are divided to square blocks which sides are equal to width of channel. The whole resistance of channel is formed by the successive connection of individual resistances of blocks. The resistance of whole card is determined by parallel connection of channels or averaging of resistance of all channels and following filling the whole area of card. The first step of analysis is the determination of advantage orientation of slides inside of every blocks. On the basis of determined orientation the block is filled by periodic structure which period is equal to the width of graphene slide and neighbouring interval. As a parameter which determines the orientation is used the angle between advantage orientation of graphene slides and axis of current flow between contacts. Owing to symmetry of task in comparison of current direction the limited meanings of corner is 0 and 90 degree. It is established two principal different cases of orientation: first – when determining angle is less than 45 degree and second when this angle is more than 45 degree. In the first case the current flows along the stripe with large conductivity. In the second case the current flows across these stripes so as through the stripes with low conductivity. It is found the smooth dependence of block resistivity from the angle of strip orientation. For the characteristic of area which is filled graphene slides it is proposed the coefficient of filling which is determined by binary discretization method. On the basis of analysis of slides orientation and filling coefficients are calculated the resistance of individual blocks. The resistances of all channels of investigated card are proposed. By using two methods – parallel connection and averaging over all channels it is calculated the specific electrical resistance and specific electrical conductivity of material as a whole. It is found that the received values of specific conductivity exceed the determined in experiment value in several (to 10) times. For the coordination of calculated value with experimental value it is made the variation of specific resistances of graphene slides and intervals between its. It id found that the calculation by method of parallel connection of channels ensures several better coordination than method of averaging. It is shown that the resistance is improved in the first turn by the increasing the resistance of interval between slides. In the quality of possible reason of decisive role of interval it is proposed the observed in experiment sharp non-homogeneity of relative arrangement of graphene slides. It is discussed the possible courses of further development of work. As a most important task it is proposed the more circumstantial determination of statistical character of received results.

Modern Technologies of Metal Processing in the Socio-Cultural Context

The study analyzes the specifics of modern metal processing technologies. The results of laboratory research for samples made from structural steel St3 with various heat treatment are presented. The results of mechanical tests, measurements of the relaxation coercive field force are shown. The processes that occur with the structure during heat treatment are studied and described. It is made by x-ray diffractograms and images obtained with raster electron and optical microscopes. The influence of structural changes on the relaxation coercive field force and mechanical parameters is described.

Native gold in the weathering crust of the Nizhneselemdzhinsky gold-bearing node (Amur region)

Research subject. The weathering crust of Proterozoic slates in the Neklya River basin and Paleozoic granites in the Nizh- neselemdzhinsky gold-bearing node (NGBN) in the Tatarka River basin.Methods. The research was carried out using the methods of atomic absorption, X-ray fluorescent and mineralogical analysis of rocks and minerals. The method of raster electron microscopy was used to study the element structure, morphological and microstructural features of minerals.Results. Specific features of native gold from the weathering crust of NGBK were defined. It was established that the NGBN weathering crust contains both hypogene gold, partially changed in the course of hypergenesis, and neogenic gold. A considerable share of gold is of high purity (1000%o). Occasionally, gold in the form of complex accretions from grains of different morphology and structure is present. A specific feature of weathering crust gold is its interpenetrations within the rock matrix of a varying mineral structure. Gold-bearing carbonaceous structures in the form of films and outgrowths on gold grains were revealed; the presence of carbon in rock components associating with the noble metal was defined. In the crust, the participation of carbon in physicochemical processes was established, as a result of which the release of Au, encapsulated in minerals-concentrators, and its redeposition on geochemical barriers occur. Gold nanoparticles can be long-acting growth centres in the host rocks, first coalescing with each other to yield nanoformations, then microforms, etc. In the weathering crust of gold deposits, both the transformation of the hypogenic noble metal and the formation of its new forms occur.Conclusion. This work contributes to the expansion of the mineral resource base of gold in the Amur Region, including through such unconventional sources as the NGBN weathering crust.

Defining patterns in the influence exerted by the interelated biochemical corrosion on concrete building structures under the conditions of a chemical enterprise

The effect of microbial and chemical corrosion on concrete structures operated in the conditions of chemical enterprises has been established that makes it possible to reliably predict the timing of their decommissioning in order to prevent industrial disasters. Even though the construction complies with all building codes, concrete structures eventually undergo chemical and biological corrosion. The innovation proposed in this study implies investigating the depth and degree of damage to concrete at the microscopic level by the method of raster electron microscopy. In addition, the TPD-MS method has been suggested for determining the quantitative and qualitative state of the carbonate components of concrete and sulfur compounds. This study has found that in concrete samples from the titanium dioxide production plant, the amount of carbon dioxide release is twice less than in control samples at t=600 °C while the level of sulfur dioxide, on the contrary, increases. This is due to the ability of thionic bacteria to accumulate sulfate acid that destroys the cementing component in concrete. The reported results confirm the impact of products of the activity of Acidithiobacillus thiooxidans microorganisms on corrosion processes in concrete. In addition, when using the TPD-MS method, it was established in the storage room of the finished product that heating the control sample of concrete leads to a release of the significant amount of СО2 at t=580–600 °C. However, the experimental samples of concrete are almost lacking carbon compounds because the acid metabolites of microfungi interfere with its formation. Microscopic and REM studies revealed the localization of Acidithiobacillus thiooxidans and Aspergillus fumigatus in concrete. This study has established patterns related to the mechanism that forms chemical compounds in concrete and the metabolism of microorganisms

Mollusken der Gattung Glycymeris aus der Vogelherd-Höhle bei Niederstotzingen (Lonetal, Südwestdeutschland)

The site of Vogelherd in the Lone Valley of southwestern Germany has become world famous for its many unique artworks made from mammoth ivory, personal ornaments, flute fragments, lithic artifacts, and antler and bone artifacts. In the study below, the molluscs from Vogelherd are presented, offering us new insights on the mobility and social behavior of Aurignacian groups in the Lone Valley. Some of the mollusc finds come from the 1931 excavation of Gustav Riek; however, most of them were uncovered during the later re-excavations of the site between 2005 and 2012. In order to provide context for these finds, we compare the molluscs from Vogelherd with those from across Central Europe. The identifiable fragments from Vogelherd belong to the genus Glycymeris. The Glycymeris molluscs originated from the Mainz Basin. This determination makes it possible to reconstruct one of the farthest long-distance connections known for the Upper Paleolithic in Germany. In addition to the Glycymeris finds, we present a tool that was also made from a mollusc. This mollusc-tool, coming from the excavation of 1931 and attributed to the Aurignacian, is a unique find for this time period of southern Germany. With this piece, along with microscopic examinations and discussions of the Glycymeris molluscs, we present a wide range of possible uses for these finds. For example, we discuss the possible use of the molluscs as ochre containers. To test this, we used EDX-analysis and a raster electron microscope. We compare the Glycymeris molluscs of Vogelherd with those from Gravettian and Magdalenian contexts at Hohle Fels, Geißenklösterle, Petersfels, and Gnirshöhle, and we provide a list of all sites from Germany, Switzerland, Eastern France, and Belgium with Glycymeris finds. We use size comparisons to show differences as well among the Glycymeris finds of Vogelherd and other Upper Paleolithic sites in southwestern Germany. In conclusion, we demonstrate that the Glycymeris molluscs of Vogelherd best fit into the Aurignacian, and we provide other Aurignacian sites that contained similar finds. By discussing other long-distance connections in the Aurignacian of southern Germany, it becomes evident that Glycymeris molluscs are not specific only to the Swabian Aurignacian.

Закономірності формування структури приповерхневого рекристалізованого шару в процесі відновлювальної термічної обробки нікелевих жароміцних сплавів

In modern nickel nickel-based high-temperature strength alloys of the ZhS32 type with a directional and single-crystal structure on surfaces that were previously subjected to mechanical treatment, with the subsequent isothermal exposure in the vicinity of the homogenization temperature lasting more than 15 minutes a subsurface recrystallized layer up to 40-65 μm deep is formed such us a chain of grains. The formation of this layer is a side effect that restrained the industrial application of vacuum heat treatment to restore local operational degradation ("raft"-structure) on the overheated inlet edges of non-bandage shelved gas-cooled high-pressure turbine blades of some modern aircraft turbine engines. Given the technical complexity of reliable removal of this recrystallized layer from the tract surface of thin-walled gas-cooled blades, it is important to develop technological measures to translate grain boundaries in unremoved residues of recrystallized near-surface layer into a safer structural state. The regularities of recrystallized layer formation in the process of 3-stage reductive vacuum treatment has been investigated by the methods of raster electron microscopy and X-ray structural (EDX) microanalysis at magnification up to × 2000 on fragments of TVT blades with ZhS26-VI alloy (directional structure) and ZhS32-VI alloy (monocrystalline structure). It has been established that the recrystallized layer formed in the process of aging 1.25-1.5 hours at the temperature of alloy homogenization, is a chain of grain with a tightly packed γ׳-phase with layers at their boundaries, which consist of the non-reinforcing γ׳-phase up to 1-3 μm wide with the carbide phases presence. It has been shown that the rational choice of the temperature of high-temperature aging is an effective technological control of the grain boundaries structural state in a near-surface recrystallized layer of the considered high-temperature strength alloys. Assigning a temperature of 1050°C for isothermal exposure after homogenization heat treatment for ZhS26 and ZhS32 alloys allows to reduce the grain boundaries width in the recrystallized layer to 1-2 μm, keep them intermittent and avoid systematic release of carbide particles at the grain boundaries. On the basis of established in the Paton welding institute of regularities of formation and control of the structure of the near-surface recrystallized layer developed technological recommendations for optimizing the vacuum heat treatment modes to restore the structure of non-bandage shelved gas-cooled high-pressure turbine blades with type ZhS32 high-temperature strength alloys. This technology has passed experimental and practical testing during the next maintenance cycle of flight operation on one of the modern turbojet double-circuit gas turbine engines with afterburner combustion chamber. Keywords: nickel nickel-based high-temperature strength alloys, vacuum heat treatment, restoration of alloys structure, subsurface recrystallized layer, raster electron microscopy.

Применение метода декомпозиции для расчета проводимости шунгита на основе электронно-микроскопических карт распределения углерода.

The outlook of using the shungite for covering large area which can protect something from electromagnetic radiation is described. As a main parameter which determines the efficiency of created screens is determined the specific electrical conductivity of shungite carbon. For the measuring of conductivity it is proposed to use the high-resolution raster electron microscopy which make be possible to obtain the card of carbon distribution in the scale of some nanometers. The method of binarization of this card is proposed. This binare card describes the spatial distribution of two phases – large-conducting and small-conducting. The large-conducting phase consist of graphene slides. The small-conducting phase consist of chaotic distributed atoms of carbon. On the basis of binare card it is constructed the flat-area block which is looked as net from square cells having two colours – black and white which correspond one by one to large and small-conducting phases. On the area of block it is selected tubes of current which consist of straight chains of black and white cells connected in succession. The whole resistance of block is determined by parallel connection of these tubes. It is proposed the procedure of constructing this symmetrical block along two coordinates. The scheme of this construction is proposed. The calculation of block resistivity along two coordinates is executed. On the basis of flat-area block it is constructed the space elementary block which has equal to each other resistance along three coordinates. For the determination of specific resistance of material as a whole it is carried out the procedure of decomposition which consist of presentation the unit volume of specimen as a set of elementary blocks. For the real specimens of shungite from two natural deposits it is made the calculation of specific resistance and specific conductivity of shungite carbon. It is established that the calculated data are coincide with data received by contact method in the accuracy of 30%. As a most advantage of proposed method it is established the possibility of conductivity measuring of carbon part of shungite in the scale of some units of nanometers.

Фрактографічний аналіз іонноазотованих зразків з алюмінієвих поршнів двигунів сільськогосподарської техніки

For a more detailed study of kinetics and the mechanism of destruction, the influence of the environment and the load on the resistance of the samples with heat-protecting diffusion ion-accounted layers, a number of additional fractographic studies should be carried out. The presence of this information will increase the strength and reliability of both coatings and coatings in the stage of their design. In the work, a fractographic analysis of ionic nitrogen samples from aluminum pistons of agro-industrial machinery engines using a method of raster electron microscopy on a microscope Micro analyzer "Samssn-4DV" was performed. Determination of the chemical composition of the surface of the samples, as well as various phases, imperfections and inclusions was carried out in this paper using the X-ray spectral microanalysis method (RSMA). It has been established that the mechanism of kinetics of the process of destruction is reduced to the gradual growth of microcracks to a critical size as a result of the rupture of atomic bonds in the vertex of the crack with stresses, which exceeds the conditional limit of the content of the "base-coating" composition. There is an emergence and growth of the same types of cracks. Then the cracks are increasingly revealed and the length and depth increases. The intensive local oxidation of the base in the area of the coating defect leads to a reduction in the cross-section and the growth of acting stress. The consequence of this is an increase in the creep speed, which in turn leads to the development of the initial defect and to the progressive process of destruction in non-additive operating factors. It has been found that the bases defects are destroying the coating. In addition, it has been found that the deformation of the sample is carried out at the expense of the displacement processes. Confirmation of this is the characteristic lines of Chernova-Leuders. Conclusions. It has been shown that the mechanism of destruction process is reduced to the gradual growth of microcracks as a result of the rupture of atomic bonds in the vertex of the crack at strains, which exceeds the conditional line of fluidity of the "base-coating" composition. The presence of areas of the base is established, which as a result of a violation of the strength of the strengthened surface layer interact with the environment and affect the increase of plasticity due to the disclosure of defects. This increases the creep speed, which in turn leads to the progressive process of destruction in the simultaneous operation of operational factors.

Метод и реализация высокоэффективной диагностики формы электронного зонда растрового электронного микроскопа

An important unit of an electron microscope is the system controlling the electron beam, responsible for raster forming on the specimen and the electron probe focusing, which provides an achievement of minimum of aberrations and the maximum of resolving capacity of formed electron image. During using electron microscope the image quality gradually deteriorates, manifesting the resolving capacity reduction and the astigmatism appearance. An attachment developed for the raster electron microscope, permitting to perform the highly effective diagnostics of the configuration of the scanning electron beam, controlled by a precision magneto-optical system, has been offered. It has been shown that the direct visual observing the scanning electron probe, in particular the evaluation of the ellipticity of its cross-section using the WEB camera matrix, combined with the sample plane, as a result, provides more efficient tuning and repair of the scanning electron microscope.

Analysis of the Effect of Transmembrane Pressure on the Change in the Structural and Transport Properties of Active and Drainage Layers of Composite Films UPM-50 and UPM-100

Results are presented from investigating active and drainage layers of composite films (membranes) UPM-50 and UPM-100 before and after exposure to transmembrane pressure by means of IR spectra of reflection, X-ray scattering, and raster electron microscopy. It is found that changes in the IR spectrum of the working sample are caused by the destruction of weak bonds of C=O···H–N amide fragments of the polysulfonamide film. A drop in (C=O) vibration frequency ν by Δν = 20 cm−1 indicates redistribution of the electron density between C=O-groups and benzene rings as a result of the inductive effect of coupling, which results in the formation of charged functional groups CO−. The presence of CO– groups fragments a new supramolecular structure whose stability due to the dipole–dipole interaction of carbonyl anions. X-ray scattering of the initial and working samples in the 10°–35° range of angles 2θ is determined by three intense reflections at angles 2θ ~ 17.23°, 22.24°, 25.41° from crystallographic planes ((010), (100), and (110)) corresponding to the crystalline structure of lavsan (polyethylene terephthalate). A comparative analysis of the reduced intensities of reflections from crystallographic planes (010), (100) and the sizes of lamellas indicates that transmembrane pressure initiates conformational rearrangement of crystallites with crystallographic axis b oriented parallel to the film plane.

Man-made soils and mining wastes as raw materials for building composites

The crucial task up to date is to find effective solutions to expand the raw material base of the construction industry by involving local natural and man-made raw materials instead of traditional expensive energy-intensive materials. An inexhaustible source of raw materials can be mining waste, such as dolomite and lime. Currently, they are large-tonnage industrial deposits that limit the area of development. The problems of strengthening man-made cohesive soils for the manufacture of wall materials, and their use as natural bases is also front and center. The optimal compositions of soil-concrete mixtures based on waste carbonate deposits are selected. The goal of this work was to design a composition of a complex binder for strengthening clay soil. The second goal of the work was to obtain masonry soil-concrete products. For this purpose, waste from the dolomite production of the Melekhovsky deposit was used. To solve the problems, authors carried out such tests as chemical analysis, mineralogical analysis, X-ray phase analysis, raster electron microscopy, compressive strength test, frost resistance test, and water resistance test. Comparing the obtained results, it is now becoming apparent that the compositions of GD-4 and GD-5 at close density values have high strength characteristics at design age. The content of dolomite waste above 30% leads to an increase in strength, the best results are achieved with a dolomite content of 34.6-45.3%, in this range also with increasing binder content, water absorption and density increase, and therefore porosity decreases. The phosphates that make up the composite increase its water resistance.

Some particularities of microscopic investigation of non-metallic objects

Thearticledealswith the comparative application of optical and raster microscopy for non-metallic objects and non-conducting surfaces. It is noted that this issue is not covered much in the special literature. There are practically no publications that compare and describe photos of the structure of materials obtained using fundamentally different microscopes, in particular, metallographic and raster. The causes of image distortion in a raster electron microscope in the study of dielectrics are considered. Comparative images of the oxidized surface, fabrics and natural leather obtained using raster and optical microscopy are presented. The advantages of optical microscopy in the study of non-conducting surfaces are shown.

Morphofunctional Aspects of Bone Tissue at Osteoporosis

Objective: morphofunctional aspects of bone tissue at osteoporo-sis. Methods: The clinical material of 117 patients with isolated and multiple fractures of typical localizations on background of systemic osteoporosis as well with degenerative diseases of the musculoskele-tal system, which were presented by deforming arthrosis of hip joints of 3rd degree. The specimens of bone tissue were browsed and pho-tographed in light microscope «TOPIC-T» CETI. The specimens were fixed in standard glutaraldehyde fixative and then they were browsed in raster electron microscope «FE1 Quanta 200 3D» и «FE1 Quanta 600 FEG»( Netherlands). The processing and formation of AFM- images were conducted using software «NOVA»(NT-MDT, Russia) and «Image Analysis» (NT-MDT, Russia). Results: The decreasing of total area of bone tissue was morpholog-ical manifestation of osteoporosis. Normal bone plates in cancellous bone became thin and perforated, trabecular lattice system also be-came thinner and partially interrupted. Trabeculae became thin, distance between them increased, what led to spreading of bone marrow space. The structure of Havers canals was violated. The thinning of tissue in cancellous substance was due to transformation of endoste-al layer of cortical bone. The fibres of intercellular substance of bone tissue were placed randomly, large intervals were between bunches. Conclusions: At exploration of morphofunctional features of bone tissue at osteoporosis it was founded that the decreasing of total area of solid substance in bone tissue took place. In cancellous substance bone plates became perforated and thin, collapsed, forming large cavities. Trabecular lattice system became thin and partially interrupt-ed. Trabeculae became thin, distance between them increased.

INFLUENCE OF TIME MODES OF THERMAL TREATMENT ON Pt-Si SYSTEM MICROSTRUCTURE

The paper is purposed to establish the principles of the micro-structural changes of Pt-Si system during the rapid thermal treatment. The Pt films 43.7 nm thick were applied on the substrates of mono-crystal silicon KEF 0.5 with orientation (111) by means of the magnetron platinum target sputtering (purity of 99.95 %) on the unit MPC 603 with the cryogen pumping to the pressure of no less than 5∙10-5 Pa. Argon was used as a working medium, whose purity constituted 99.933 %. Rapid thermal treatment was performed in the mode of the thermal balance with irradiation of the reverse side of the wafer by means of the non-coherent light flow in the nitrogen medium within the temperature range from 200 to 550 °C with a step of 50 °С during 7 s. In parallel, the solid phase synthesis was performed of platinum silicide by means of the standard method with application of the continuous single stage thermal treatment in the analogue medium (T = 550 °C, t = 30 min). Temperature monitoring was performed by means of the thermal couple method with accuracy of ±0.5 °C. The grain size was determined by the translucent electron microscopy method. Thickness of platinum silicide under formation, its surface micro-relief and the separation boundaries with silicon were determined by means of the raster electron microscopy. It is demonstrated, that with the rise of the rapid thermal treatment one can observe growth of the platinum film on silicon. A comparative analysis was conducted of the average size of grains, micro-relief of the PtSi surface and its separation boundary with silicon for two methods of its formation with application of the rapid thermal treatment and with application of the traditional continuous thermal treatment at the temperature of 550 °C during 30 min in the nitrogen atmosphere. By means of the raster electron microscopy method it is demonstrated, that size of the micro-relief on the separation boundary of PtSi-Si does not exceed 15.9 nm and the size of grains is 37.7 nm. This is in 2.5 and 3.1 times smaller, then in the case of the traditional single stage continuous thermal treatment.

Study of Electric Spark Coatings Properties Obtained by Electrodes from Titanium Electroerosive Particles

Purpose of reseach. Modern car is a very complex system which has about 15... 20 thousand parts. More than 7 thousand lose their initial characteristics during operational process. As practice shows, more than 4000 car parts lose their operability much earlier than the expiration of vehicle life as a whole. These factors lead to significant repair costs, as well as profit losses caused by long delays in part of the rolling stock. Efficiency and qualitative improvement growth of various areas of public production pose new and more complex tasks to increase the efficiency and reliability of parts. These tasks can be solved both by creating special innovative materials and by developing and introducing into production the latest methods of car parts strengthening and applying protective coatings. Electric spark alloying of metal surfaces is one of these methods. Electric spark alloying is widespread in most industries, including automotive manufacturing, mechanical engineering and metalworking. Electric spark alloying method provides high degree of adhesion, high efficiency and low energy consumption. Electrodes with nano particles are of greatest interest. The most promising method is electroerosive dispersion used in the production of nano materials. The purpose of the work is to study coatings' properties obtained by electric spark alloying using powder electrodes made from electroerosive particles obtained in distilled water from titanium alloy wastes of grade ВТ6.Methods. ВТ6 grade chips were used to prepare titanium powder by electroerosive dispersion. Consolidation of the particles received by electroerosive dispersion of BT6 titanic alloy waste is done by spark plasma agglomeration method with the use of spark plasma agglomeration system of SPS 25-10. UR-121 installation was used to cover electrospark coverings. Experimental pictures on QUANTA 600 FEG raster (scanning) electronic microscope were made to study coverings' form and morphology. X-ray spectrum analysis was performed by EDAX 's energy dispersion X-ray analyzer built into QUANTA 600 FEG raster electron microscope. Surface roughness of samples was examined on SURTRONIC 25 profilometer.Results. It was experimentally stated that titanium, oxygen, aluminium and tungsten are the main elements in the sintered sample of titanium particles obtained in distilled water. It was stated as a result of properties investigation of powder electrodes from electroerosive particles and coatings obtained by electrospark alloying. Other elements are present in minor amounts. Roughness of electric spark coated samples is Rz 13.2 um (Ra 2.14 um). These particles obtained in water distilled from ВТ6 titanium alloy waste can be used for electrodes suitable for automotive parts recovering by electric spark alloying.Conclusion. Obtained results can be used in creation of resource-saving processes of metal alloys and composite materials.

Сравнительная оценка эффективности различных методов профессиональной гигиены полости рта

Introduction. Modern treatment of inflammatory diseases of parodon tissues implies consistency throughout the treatment. Initially, much depends on a high-quality procedure for the removal of dental deposits with further polishing of the tooth root surface. At the moment, doctors use a variety of methods to remove dental deposits in their daily practice. Most authors in their research describe only the advantages and disadvantages of removal of dental deposits, only slipping on the impact of these methods on the condition of hard tissues of the tooth, often these data are contradictory. The purpose of this study is to compare the effectiveness of various occupational oral hygiene methods. Materials and methods. We selected 30 patients suffering from moderate chronic generalized periodontitis between the ages of 20 and 50 to determine the test groups. We used the Cam Scan (REM) raster electron microscope to evaluate the treated surface of the tooth root cement and enamel. We assessed individual oral hygiene level and periodontal tissue condition using hygienic indices such as: OHI-S, API, PHP, hemorrhage index, PI. Results of a research. Objectively, among all patients cyanotic gums and gum edges dominated, mobility is absent, bleeding, loose gum consistency, the presence of paradoxontal pockets and serous-purulent exudate. Practically complete removal of dental deposits from the root cement and in the neck region of the tooth enamel appear during treatment with a UT-scaler, in the area of the tooth neck there are different areas by the degree of roughness. Conclusions. After analyzing the data obtained from our study, we were able to determine the quality of various methods of dental sediment removal and the effect on the microstructure of enamel and cement of tooth root. There is the least effect on the microstructure of the cement of the tooth root by the operation of the scaler, qualitative removal of dental deposits was achieved with minimal influence on the microstructure of the cement of the root and enamel of the tooth.

EFFECT OF RAPID THERMAL TREATMENT CONDITIONS ON ELECTROPHYSICAL PROPERTIES OF CROMIUM THIN FILMS ON SILICON

Present paper is devoted the determination of the effect of the temperature of the process of rapid thermal treatment of chromium films on n-type conductivity silicon on their resistivity and contact properties of the interface. Chromium films of about 30 nm thickness were deposited by magnetron sputtering onto the surface of silicon substrates having a resistivity of 0.58 to 0.53 ohms×cm. The rapid thermal treatment was carried out in a heat balance mode by irradiating the back side of the substrates with non-coherent light flux in nitrogen ambient for 7 seconds. Quartz halogen incandescent lamps were used as the heating source. The temperature of the rapid thermal process ranged from 200 to 550 °C. The thickness of the chromium films was determined by raster electron microscopy. The surface resistance of the samples was measured by a four- probe method. The Schottky barrier height and the ideality factor were determined from I-V plots. It is shown that at the temperature of the rapid thermal process 400 °C a layer of chromium disilicide is formed, causing a sharp increase in the resistivity of chromium films to 1.2 mOhm×cm and the height of the Schottky barrier to 0.6 V. When the temperature of the rapid thermal process is further increased to 550 °C, the resistivity increases monotonically to 4.0 mOhm×cm due to the increase in the width of the interstitial boundaries increasing the scattering of charge carriers in the CrSi2 layers. It has also been shown that rapid thermal treatment of the Cr/Si structure at a temperature of 450–500 °C enables to obtain rectifying contacts with a barrier height of 0.615 V and an ideality factor of 1.1. The results obtained can be used in the technology of integrated electronics products containing Schottky contacts as well as thin film resistors.

Deposition of boron-containing coatings by electron-beam evaporation of boron-containing targets

Boron-containing films are promising materials for improving the hardness, wear-resistance and durability of mechanical parts used in industry. We describe a novel approach for deposition of such coatings – by using electron-beam evaporation of boron-containing target material (pure boron or boron nitride) in inert (helium) or chemically-active (oxygen, nitrogen, residual atmosphere) gases at medium vacuum. Boron-containing films deposited on titanium substrates were characterized using a nanohardness tester and a non-contact 3D profilometer. Elemental composition of the coatings was studied using raster electron microscope equipped with a device for EDX analysis. All boron-containing coatings provided significant improvement (by a factor of 4–16) in the microhardness of the substrate surface.

Development and Research of Flux-Cored Electrodes For Welding And Surfacing Of Parts From Aluminum And Titanium Alloys

Perpose of research was to study the properties of powder materials obtained from aluminum and titanium waste by the method of electroerosion dispersion for the development of electrodes suitable for welding and surfacing of parts from aluminum and titanium alloys. Methods . To obtain an aluminum powder material by electroerosion dispersion method, an aluminum wire GOST 14838-78 was used, pre-cut to 5-7 cm. the Wire was loaded into a reactor filled with a working liquid – distilled. The process was carried out at the following electrical parameters: discharge capacitor capacity 65 UF, voltage 100 V, pulse frequency 100 Hz. To obtain a titanium powder material by electroerosion dispersion method, shavings of VT6 grade were used. The chips were loaded into a reactor filled with a working liquid – distilled water. The process is carried out at the following electrical parameters: capacity of the bit capacitors 65 µf, a voltage of 150 V, pulse frequency of 250 Hz. The result of the local effects of intermittent electrical discharges between the electrodes was the destruction of the material with the formation of dispersed particles of powder. In order to study the shape and morphology of powder material particles obtained by electroerosion dispersion from aluminum waste, images were taken on a raster (scanning) electron microscope QUANTA 600 FEG. The study of granulometric composition of powder materials obtained by the method of electroerosion dispersion of aluminum and titanium waste was carried out on a laser analyzer particle size Analysette 22 NanoTec. Results. It is established that the most promising and not industrially used materials for the production of electrodes used in welding and surfacing of parts are powder materials obtained by electroerosion dispersion. It is experimentally established that the powder materials obtained by electroerosive dispersion of aluminum and titanium wastes consist of spherical and elliptical particles. The results of the study of the elemental composition of powder materials obtained by electroerosive dispersion of aluminum and titanium waste, it is shown that the main elements of the powders produced and aluminum waste are aluminum and oxygen, and the main elements of the powders produced and shavings of the VT6 BRAND are Ti, Al, O, V, Fe, W and K. Studies of the particle size distribution of powder materials obtained by electroerosion dispersion showed that the average particle size of powders obtained from aluminum waste is 19.08 microns, and the average particle size of powders obtained from titanium waste is 33.12 microns. It is established that the most promising method for the production of electrodes used for welding and surfacing of parts from aluminum and titanium alloys is the method of spark plasma sintering. Conclusion . The obtained results can be used to create resource-saving processes for processing metal alloys and composite materials.

Formation of non-vertical mesa structures on 4H-SiC RIE method using silicone-organic mask coating

The article discusses the possibility of using silicone lacquer as a masking coating when creating micro-dimensional mesa structures on the 4H-SiC surface using the reactive ion-plasma etching method. The etching process was carried out on a setup with an ICP plasma source. The experiments were performed with the aim of determining the dependence of the angle of inclination of the wall of the mesa structure on the parameters of the etching process. The etching results were recorded with a Helius nanolab instrument complex and a Quanta Inspec raster electron microscope.