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The course of the COVID-19 pandemic has led to a critical increase in the burden on virtually all major branches of the health care system in our country and abroad. The aim of this article is to analyse the activities of the different parts of the city nephrol­ogy service in Saint-Petersburg and to consider promising ways to improve it. The nephrology service for the adult population in St. Petersburg includes: outpatient service; inpatient service - 183 beds in 24-hour inpatient departments of the city; dialysis service - 10 dialysis units in municipal medical organizations, 5 in federal institutions, and 8 centers/departments operating in the framework of private-public partnership. The number of patients on dialysis programme decreased by 10.5 % to 1,839 in 2021. These changes are likely due to an increase in mortality among these patients in 2020 and 2021 which is a consequence not only of COVID-19 but also of the adverse impact of the pandemic on the health system. The proportion of patients treated as outpatients in private dialysis centres increased during the three-year period. The incidence of arteriovenous fistula formation in primary vascular access decreased from 33.2 % to 14.2 % in 2020 compared with 2019. At the same time, the use of temporary central venous catheters as primary vascular access for renal replacement therapy has increased significantly from 43.0 % to 61.9 %. The development of the nephrology service is largely determined by its funding. To compensate the costs of medical in­ stitutions in the city for conducting renal replacement therapy it is necessary to increase the tariffs of compulsory health insurance (CHI) by at least 50 %. In the medical organizations of Saint-Petersburg municipal and federal subordination the share of "artificial kidney" devices that have used up their resource is 32.2 %, and in a number of medical institutions it exceeds 50 %.

Lipoprotein(a) [Lp(a)] is a subclass of lipoproteins consisting of a cholesterol-rich low-density lipoprotein (LDL) particle with a single apolipoprotein B100 molecule covalently bound (via a disulfide bridge) to a unique hydrophilic high-glycosylated protein called apolipoprotein a [apo(a)]. To date, there is sufficient evidence to consider an increase Lp(a) level as a causal and independent risk factor for cardiovascular disease and calcifying aortic valve stenosis. Plasma concentration of Lp(a) can vary in a wide range, which is mainly determined by genetic factors. Up to 30 % of the world's population has an elevated Lp(a) level, but this category of lipid disorders has not been currently receiving adequate attention. Determining the Lp(a) plasma concentrations is not included in the standard lipid profile, so a significant number of individuals with hyperlipoproteinemia(a) who could potentially benefit from treatment remain undiagnosed. Certain significant obstacles are still associated with the lack of standardized assay for measuring Lp(a) concentrations and a consensus on its optimal levels in blood plasma. Although some limited but statistically significant data suggest a possible benefit of lipoprotein(a) lowering on cardiovascular outcomes, no specific recommendations were made for the management of that dyslipidemia in the latest guidelines. Plasma Lp(a) levels reflect a balance of Lp(a) synthesis, which occurs in the liver, and catabolism, which is thought to involve the kidney. Lp(a) concentration begins already to increase in the earliest stages of chronic kidney disease, and patients with nephrotic syndrome have a four-fold elevated Lp(a) in comparison to healthy individuals. However, it remains unclear if elevated Lp(a) levels affect cardiovascular risk in patients with kidney diseases. This article summarizes the main data regarding the relationship between Lp(a) content, impaired renal function, and an increased risk of adverse cardiovascular events.

The choice of non-drug methods for the treatment of systemic scleroderma is currently very limited. Several studies show that extracorporeal photochemotherapy can improve kidney and lung function and reduce skin fibrosis in patients with systemic scleroderma. We studied the dynamics of clinical and laboratory parameters in patients with systemic scleroderma with an assessment before and after 12 months against the background of complex treatment, which included programmed extracorporeal photochemotherapy. Indications for inclusion in the study was the ineffectiveness of standard therapy with glucocorticoids and cytostatics or the impossibility of their use, as well as signs of an unfavorable prognosis of the disease: diffuse form, high skin count (14), rapid progression with a significant initial decrease in the glomerular filtration rate, forced vital capacity, high immunological activity (high titer of antinuclear factor and positivity for antibodies to Scl-70). When evaluating the results of complex treatment, a good clinical effect was observed in all patients: the induration of the skin decreased, the functionality of the lungs and kidneys increased. A significant decrease in the disease activity index was noted. These positive changes were the basis for a decrease in the daily dose of glucocorticoids. Significantly significant changes were observed in a decrease in the immunological activity of the disease: levels of C-reactive protein, erythrocyte sedimentation rate and immunoglobulin G, antinuclear factor titer and all types of circulating immune complexes. The results of our study confirm the data of other studies that demonstrated the positive effect of extracorporeal photochemotherapy as a component of the complex treatment of systemic scleroderma.

The results of complex treatment with the programmed procedures of extracorporeal photopheresis and methotrexate in patients with psoriatic arthritis for 12 months are presented. It has been established that program extracorporeal photopheresis in combination with basic therapy with methotrexate in patients with psoriatic arthritis have a significant effect on the relief of articular syndrome (reduction of morning stiffness, pain intensity, joint swelling). It was revealed that the inclusion of programmed extracorporeal photopheresis and methotrexate in the complex treatment of psoriatic arthritis reduces the level of circulating low molecular weight, medium molecular weight and high molecular weight immune complexes and in most cases leads to clinical and immunological remission. This is confirmed by a decrease in complaints of the severity of articular syndrome and a decrease in the clinical and laboratory activity of the disease (a significant decrease in the level of C-reactive protein, erythrocyte sedimentation rate). A scheme has been developed for the programmed use of extracorporeal photopheresis procedures in the complex treatment of psoriatic arthritis, which consists of 2 procedures every other day with an interval of 2,5-3 months for 12 months. Combined therapy with the programmed application of extracorporeal photopheresis procedures and methotrexate prolongs the period of disease remission and can be recommended for patients with psoriatic arthritis with high activity, insufficient effect of basic therapy and intolerance to higher doses of immunosuppressive drugs.

IgG4-related disease (IgG4-RD) currently is considered as a chronic fibroinflammatory immune-mediated multisystemic condition of unidentified etiology, which can imitate a wide range of malignant, infectious, rheumatologic, and other diseases. It can affect almost any organ system in the body synchronously or sequentially, but the most often affected are the pancreas, hepatobiliary tract, periorbital structures, salivary glands, kidneys, and lymph nodes. The most frequent renal manifestations of IgG4-RD is IgG4-related tubulointerstitial nephritis. Membranous nephropathy is the most common glomerular disease accompanied by IgG4-RD. Regardless of the organ localization, patients with IgG4-RD are characterized by elevated serum IgG4, but this laboratory abnormality is not specific and can be changed in other diseases. In all suspected cases of IgG4-RD the diagnosis should be confirmed by histological examination. Characteristic pathologic features include diffuse or focal lymphoplasmacytic infiltration with prominent IgG4+ plasma cells, storiform fibrosis, and obliterative phlebitis. Patients with IgG4- RD usually have an excellent clinical response to glucocorticoids, but relapse rates after steroid withdrawal are high, which may require additional use of immunosuppressants or rituximab. Due to the low prevalence and multitude of clinical manifestations the disease often remains underdiagnosed on time. This case report describes middle-aged patients with a history of chronic recurrent pancreatitis complicated by the nephrotic syndrome. Kidney biopsy showed membranous nephropathy and diagnosis IgG4-RD with multiorgan involvement was made. Partial remission was achieved on corticosteroid therapy. The presented case clearly demonstrates the difficulties of diagnosis and treatment of IgG4-RD. IgG4-related membranous nephropathy should be included in the differential diagnosis for patients with nephrotic syndrome accompanied by multiorgan dysfunction.

Relevance. Discussion of the criteria for decision making “amputation vs. preservation”, when viability of the extremity is uncertain, has been continuing. The case description. The lower extremity of a serviceman was injured by a caterpillar tractor. The severity of the damage was determined by the following conditions: open segmental fracture of the femoral diaphysis, 5 cm traction-compression damage of the popliteal artery, acute thrombosis of the popliteal and tibial arteries, sciatic nerve damage, circular detachment of the thigh skin, acute hemorrhage, II degree shock, and uncompensated lower extremity ischemia throughout 24 hours. The MESS score of the injured extremity was 8 indicating that an amputation would have been considered. Nevertheless, we choose the organ preservation solution with the revascularization of the injured limb segment. A multi-stage treatment was carried out including stabilization of bone fragments, primary reconstruction of the popliteal artery to restore the arterial blood flow in the injured extremity, reperfusion injury and myoglobinuria elimination, intensive kidney protection therapy, infection management, skin defects replacement, orthopedic surgery. As a result of the treatment, the injured limb was saved. The femur fracture healed allowing the patient to walk without assistance. Conclusion. The use of the programmed surgical treatment for severe mechanical injury of the lower extremity, an individual multi disciplinary approach, assessing the severity of systemic disorders, and timely use of extracorporeal detoxification made it possible to avoid amputation, perform organ preservation surgery, and create favorable conditions for restoring the supporting function of the lower extremity.

BACKGROUND. The lack of data on the epidemiology of presarcopenia/sarcopenia leads to an underestimation of the role of this condition in the structure of morbidity and mortality of haemodialysis patients in theRussian Federation. THE AIM: to study the epidemiological aspects of presarcopenia /sarcopenia in patients with chronic kidney disease stage 5d. PATIENTS AND METHODS. This study comprised 317 patients receiving programmed bicarbonate haemodialysis for 8.2 ± 5.1 years, among them 171 women and 146 men, the average age was 57.1 ± 11.3 years. The assessment of the presence of sarcopenia was performed using the method recommended by the European Working Group on Sarcopenia in Older People. RESULTS. The prevalence of presarcopenia was 0.7 % and sarcopenia 29.6 %. The incidence of skeletal muscle mass deficiency according to muscle mass index (IMM) was 30.3 %, 48.7 % showed a decrease in muscle strength according to dynamometry, and low performance of skeletal muscles according to 6 minute walk test was determined in 42.8 %. Sarcopenia patients were significantly characterized by lower body mass index, as well as higher body fat mass values. The duration of haemodialysis (χ2 = 22.376, p = 0.0001) and the patient's age (χ2 = 10.545 p = 0.014) were an independent risk factors for the development of sarcopenia. CONCLUSION. Sarcopenia is recorded more frequently in hemodialysis patients than presarcopenia. Its prevalence increases among patients of older age groups and with a hemodialysis duration of more than 5 years. The age and experience of dialysis make their independent contribution to the development of this syndrome.

This article is a continuation of our previous studies of the frictional anisotropy of metal nanoparticles on the surface of a graphene substrate for other temperature conditions. The friction force acting on palladium nanoparticles on a graphene sheet in various lateral directions is investigated using classical molecular dynamics modelling. Anisotropy is studied at high sliding speeds of nanoparticles consisting of 10000 atoms on the surface of graphene. The effect of incommensurability and short-range order of the contact surfaces of nanoparticles, as well as the graphene deformation lead to the absence of an expressed angular dependence of the friction force., 6 pages, 4 figures

The results of the determination of levels of apoptosis in vitro in lymphocytes during the procedures of extracorporeal photochemotherapy (extracorporeal photopheresis) using flow cytometry are described. It was found that carrying out extracorporeal photopheresis does not have a significant effect on the viability of cells immediately after the procedures. Thus, the relative content of living cells in the samples after isolation of the mononuclear fraction of peripheral blood did not differ from both samples prepared for photopheresis and samples after this procedure. It should be noted that carrying out extracorporeal photopheresis does not lead to rapid cell death. At the same time, the level of living lymphocytes at the beginning of the experiment averaged about 90%, while the protocol used to extract the mononuclear fraction of peripheral blood cells and further manipulations with them in vitro allowed increasing the percentage of living cells in the samples to90% or more. An increase in the level of cells in the early stages of apoptosis occurs already in the first day after the beginning of the experiment, which is confirmed by the data of other researchers indicating that there are significant differences in the viability of cells with an initial point in the interval of 20-24 h in vitro incubation. The launch of the processes of programmed cell death in the case of own experiments was not related to the preparation of samples for extracorporeal photopheresis (as evidenced by the absence of significant differences between freshly isolated lymphocytes and samples prepared for the procedure), but with the procedure of photopheresis itself.

The results of combined treatment of systemic lupus erythematosus with the use of extracorporeal hemocorrection on the background of replacement therapy for kidney function are presented. The dynamics of the activity of the disease, assessed on the scales recommended by the European League against rheumatism, is presented. The analysis of humoral immunity indices and markers of inflammation before and after the application of efferent therapy methods is carried out. Thus, after applying the first operation cascade plasma filtration using fractionator plasma «Cascadeflo EC40», was a decrease in disease activity with a very high to a high degree, also decreased the activity of systemic lupus erythematosus with high to low degrees of activity after application of the second operation of systemic lupus erythematosus using plasma fractionator «Cascadeflo EC20». The results of combined treatment testify to the high effectiveness of therapeutic apheresis in the complex treatment of systemic lupus erythematosus. Operations cascade plasma filtration as part of combination immunosuppressive therapy allows to correct the main factors of the pathogenesis of systemic lupus erythematosus (antinuclear factor, antibodies to double-deoxyribonucleic acid, antibodies to histones, total immunoglobulins of classes G, M, A, circulating immune complexes, inflammation markers) selectively removing them from the vascular bed. Thus, the inclusion cascade plasmafiltration operation in the combined treatment of systemic lupus erythematosus, allows to quickly remove the main factors of the pathogenesis, which leads to a rapid decrease in the disease activity and reduces the dosages of cytostatic and glucocorticoid therapy.

Background: The frictional properties of nanoparticles have been studied to gain insight into the fundamental origin of sliding friction.Results: Using molecular dynamics we investigate frictional properties of aluminum and palladium nanoparticles deposited on a graphene layer. We study the time evolution of the total momentum of the system, the total and potential energies, the temperature, the velocity and position of the center of mass, the dimensions of the nanoparticle, and the friction and substrate forces acting on the particle. We also study how the friction force depends on the nanoparticle–graphene contact area and the temperature.Conclusion: The tribological properties of nanoparticles strongly depend on the materials. The particles move in an irregular (saw-like) manner. The averaged friction force depends nearly linearly on the contact area and non-monotonously on temperature. We observe ordered crystalline domains of atoms at the bottom surface of the metal particles, but the peaks of radial distribution function are blurred indicating that the nanoparticles are amorphous or polycrystalline.

The behavior of a liquid argon layer compressed between absolutely solid diamond surfaces with a periodic atomic relief has been studied by the method of molecular dynamics. The film consists of one or two layers of molecules for which the model of absolutely elastic spheres has been used. The equilibrium and dynamic properties of the film dependently on the load and shear force applied to surfaces and the number of argon layers have been investigated. The performed modeling allows us to compare the behavior of systems with smooth and rough plates. The results show that most of the properties of ultrathin argon films confined between surfaces of both types are similar.

The frictional anisotropy of metallic nanoparticles is investigated using a molecular dynamics method. Calculations of anisotropy have been performed for aluminum, palladium, and platinum nanoparticles containing 10,000 atoms. Anisotropy is studied at high sliding velocities of nanoparticles over the graphene surface. The influences of incommensurability and short-range order of nanoparticles’ contact surfaces lead to the absence of pronounced angular dependence of frictional force.

The research of temperature properties and correlation of friction force of metallic nanoparticles on graphene is represented. Modeling was led by molecular dynamics method through CUDA-technology. Calculations have been performed for aluminum, palladium, cobalt and platinum nanoclusters containing from 10000 to 20000 atoms at the temperatures from 300 K to 1400 K. Radial distribution function is built to analyze the structural changes of nanoparticles. We discuss the strong influence of the types of metals on the form of functions describing the behavior of nanoparticles during motion.

We compare the calculation of the contact area between the palladium and aluminum nanoparticles and graphene substrate by an ellipse and by the distance between atoms. Linear approximations of shear stress depending on the contact area of different metals were compared. It has been observed that aluminum nanoparticles are spherical and palladium nanoparticles have an ellipsoid shape, because the metal-metal interaction in palladium is stronger than that of aluminum.

Using molecular dynamics method and CUDA-technology for software creation, we investigate tribological properties observed when aluminum atoms are deposited on a graphene layer. During the modeling of the shear of nanoparticles, consisting of aluminum atoms, various parameters are measured the total momentum of the system, the total and potential energies, the temperature, the velocity and position of the center of mass, the dimensions of the nanoparticle, friction and substrate forces acting on the particle. We make a conclusion that tribological properties of nanoparticles strongly depend on materials. Detected heterogeneous form of dependence of substrate force is saw-like. The power dependence of averaged friction force on contact area was obtained. Since peaks of radial distribution function are blurred consequently nanoparticle has amorphous or polycrystalline form.

Within the method of classical molecular dynamics we study the kinetic and tribological properties of molecularly thin film of liquid argon, consisting of one or two layers of molecules, squeezed by two atomically flat crystalline diamond surfaces. The model of elastic spheres for argon molecules and absolutely hard diamond plates is treated. With the help of Green-Kubo and Einstein formulas the time dependences for the autocorrelation function and diffusion coefficient are built. It is proved that increase of external load leads to a gradual transition of a film to the solid-like state. The dependences of friction force on time, external load (surface pressure), and shear force are investigated showing different rubbing modes.

ZAO ECOlab (Russia) developed Line Blot Syphilis, a new test system on the basis of the linear immunoblotting method using Treponema рallidum recombinant antigens. The article assessed the diagnostic value of the Line Blot Syphilis test system in the form of a confirmatory test. As a part of the conducted study, the test system demonstrated its absolute sensitivity and specificity to serum-positive (n = 237) and serum-negative (n = 114) samples, in which the presence or absence of Т.pallidum antibodies was confirmed by two treponemal tests. As a result of examining 14 samples attributed to doubtful analytes based on two test results (passive hemagglutination test and immunofluorescence test with absorption), the data compliance between the Line Blot Syphilis test system and data from INNO-LIA Syphilis Score amounted to 100% (14/14) or 93% (13/14) for the immune-enzyme assay and 57% (8/14) for the immunofluorescence test with absorption. It is recommended to use the Line Blot Syphilis test system (ZAO ECOlab) as a confirmatory syphilis test.

A technique based on the recording of a Fraunhofer diffraction pattern and allowing studies of structural and phase transitions in an ion-implantion-doped semiconductor layer with a high time resolution simultaneously with sample-temperature measurements is described. For this purpose, two measuring diffraction gratings—phase and amplitude—are preliminarily formed on the surface of a silicon plate. Solid-phase recrystallization and melting processes were studied using the kinetics of disappearance and appearance of diffraction peaks from the amplitude grating. The sample temperature was monitored by the deviation of the diffraction angle of a probing laser beam from the phase diffraction grating caused by a change in the grating period resulting from its thermal expansion.

A method for the fast measurement of the temperature of solids under the action of a high-power light pulse is proposed and demonstrated. This method is based on the application of the Fraunhofer diffraction and is implemented for silicon samples heated to melting temperatures Tmelt = 1412°C by a high-power light pulse. The current silicon temperature was determined by measuring the varying diffraction angle of the probing laser beam. The diffraction angle was varied over time because the period of the diffraction grating increased as a result of the dynamic thermal expansion of the crystal. An initial grating was formed on the surface of the silicon plate with a period of d = 4 µm. The radiation beam of a He-Ne laser with λ = 0.6328 µm was used as the probing beam; the measured signal was recorded in the pair of symmetric fifth-order diffraction maxima.

Dynamics of recrystallization of implanted silicon surface has been investigated using an in situ diffraction method. The method is based on registering the diffraction signal from a special periodic structure formed by ion implantation. The change of the intensity of the diffraction maximum may enable one to define the moment when recrystallization of the amorphous layer ends, the moment when the local melting of the surface starts and the duration of the stage when the liquid phase exists. Investigation of the dynamics of recrystallization and anisotropic local melting of implanted silicon under irradiation by pulses of incoherent light with different duration and power densities has been carried out. Our method enables one to carry out rapid thermal annealing with a feedback on the ending of recrystallization. This provides a better control on the formation of shallow p–n junctions.

The effect of intense atomic hydrogen flux on the defect density in the surface layer of single-crystal silicon is studied. It is shown that the formation of local molten regions by pulsed-light heating of Si samples and further analysis of the local melting pattern can be an efficient tool for determining the number of defects introduced by the processing in atomic hydrogen. It was found that the processing conditions in atomic hydrogen with an exposure dose lower than 2.7 × 1017 cm−2 do not change the number of defects in Si; in contrast, conditions with an exposure dose above 3.6 × 1018 cm−2 significantly increase the defect density. The increase in the number of defects can be caused by the interaction of atomic hydrogen with the Si surface.

Fourteen thermophilic and thermostable strains of the genus Bacillus were studied. Total DNA was isolated from these strains and used as a template to identify and clone peptide synthetase genes by means of polymerase chain reaction. Amplified DNA fragments were cloned into a phasmid vector, and nucleotide sequences of cloned fragments were determined. Stringent thermophilic strains were shown to lack genetic systems, which are responsible for the synthesis of secondary metabolites and homologous to the known peptide synthetase genes. On the contrary, thermostable strains had peptide synthetases and produced antimicrobial secondary metabolites. Analysis of nucleotide sequences and deduced amino acid sequences of cloned PCR fragments from B. licheniformis strains VK2, VK21, and VK2101 showed that they are absolutely identical. The cloned DNA fragment was found to be a portion of the open reading frame, which we termed ORF1. Data from analysis of a partial nucleotide sequence of the peptide synthetase gene of strain VK21 indicated that a 9.5-kb region of chromosomal DNA contains sequences of two genes homologous to the B. subtilis peptide synthetase genesdhbB and dhbF. Strains VK2, VK21, and VK2101 were shown to synthesize siderophores. A method for screening bacteria with peptide synthetase genes has been developed.

To study the efficacy of remaxol addition in the treatment scheme of alcohol withdrawal syndrome.Eighty patients with alcohol dependence and physical symptoms of alcohol withdrawal syndrome were enrolled. All patients received basic therapy in accordance to the applicable standards of treatment. The patients were randomized to remaxol introduced intravenously 2 times a day (morning and afternoon) in dose of 400 ml for 7 days (n=40) and saline with 25%-magnesium sulfate (10 ml) and 4% potassium chloride (10 ml) (n=40).The effectiveness of the inclusion of remaxol was expressed in a more rapid relief of asthenic syndrome, reduction of phenomena such as tension, dysphoria, headache and impaired coordination of samples. Patients treated with remaxol demonstrated a trend towards a more rapid reduction of the affective (p=0.08) and behavioral components (p=0.09) of the syndrome of pathological craving for alcohol. Hepatoprotective and detoxification properties of the drug were confirmed by the significant decline in ALT and AST activity to the 20th day of treatment. Significant positive changes in lipid metabolism (HDL to the 7th day of treatment) and a normalizing effect on the processes of tissue respiration were shown as well. No adverse effects were noted.The data obtained allow to recommend the inclusion of remaxol in the complex treatment regimens of alcohol withdrawal syndrome to improve the treatment efficacy.Цель исследования - изучение эффективности включения ремаксола в схему комплексного лечения больных с алкогольным абстинентным синдромом. Материал и методы. Лечили 80 пациентов с алкогольной зависимостью и клиническими признаками алкогольного абстинентного синдрома в стационарных условиях. Все пациенты получали базисную терапию в соответствии с применяемыми стандартами лечения; 40 больным (основная группа) был назначен ремаксол внутривенно капельно 2 раза в день (утром и днем) по 400 мл в течение 7 дней, в контрольной группе (40 человек) использовался физиологический раствор с 25% сульфатом магния (10 мл) и 4% хлоридом калия (10 мл). Результаты. Эффективность включения ремаксола в комплексную терапию состояла в более быстром купировании астенического синдрома, редукции таких явлений, как напряженность, дисфория, головная боль и нарушение координаторных проб. У пациентов, получавших ремаксол, выявлена тенденция к более быстрой редукции аффективного (р=0,08) и поведенческого (р=0,09) компонентов синдрома патологического влечения к алкоголю. Гепатопротективные и детоксикационные свойства препарата нашли подтверждение в достоверно значимом снижении показателей АЛТ и АСТ к 20-му дню лечения, кроме того выявлены достоверная положительная динамика показателей липидного обмена к 7-му дню лечения и нормализующее действие на процессы тканевого дыхания. Нежелательных явлений, связанных с исследуемым препаратом, отмечено не было. Заключение. Полученные данные позволяют рекомендовать включение ремаксола в комплексную терапию алкогольного абстинентного синдрома с целью повышения эффективности лечения.

Investigation of the dynamics of recrystallization and anisotropic local melting of implanted silicon under irradiation by pulses of incoherent light with different duration and power densities has been carried out. Dynamics of recrystallization of implanted silicon surface has been investigated in situ using a diffraction method. The method is based on the registering of the diffraction signal from a special periodic structure with high time and spatial resolution. This periodic structure is formed using special regimes of implantation of phosphorus and silicon ions in monocrystalline silicon with different fluencies.

To study the main features of local melting more detail in situ investigations of mechanism of this effect were carried out at incoherent light irradiation with different pulse durations and irradiation power densities. These investigations were made using special long-focus microscope and high-speed camera. The results of in situ investigation of the density and sizes of local molten regions on the silicon surface are presented. In this work it was established that for all used light pulse durations the dependences of density of local molten regions on time has a similar character. Three stages are observed: (1) very fast increase from 0 (at the moment of local molten regions nucleation) up to the maximum value; (2) the plateau; (3) decrease due to coalescence of neighboring local molten regions. These results are provided that local molten regions are predominantly created during a relatively short time interval. It also has good agreement with the model of superheating of the semiconductor surface with respect to the equilibrium melting point during the pulse light irradiation.

The nucleation and growth of local molten regions (LMRs) during the light irradiation was detected using high-speed camera and long-focus microscope. In situ dependences of sizes and density (quantity per cm-2) of LMRs are interpreted in the frame of the following model. A great amount of heat is transferred to the semiconductor surface during light pulse irradiation. This proces is nonstationary and the heat is not distributed homogeneously over the thickness of the sample. As a result, a specific short-lived state is formed, in which the semiconductor surface is superheated in the solid-state phase with respect to the equilibrium melting temperature. Some surface areas, which contain the defects, begin to melt. Temperature of these local molten regions immediately decreases down to the equilibrium melting temperature. The created LMRs begin to absorb the heat from neighboring superheated solid regions. As a result, the temperature of superheated regions decreases down to the equilibrium melting point. No new local molten regions are formed and the sizes of existing local molten regions increase due to absorption of the energy of light pulse. To study the main features of local melting more detail in-situ investigations of mechanism of this effect were carried out at incoherent light irradiation with different pulse durations and irradiation power densities. The last our results agree with the superheating model. Also the dynamics of phase transitions on the surface of implanted silicon at different regimes of light pulses is investigated using high-speed camera and special diffraction gratings. The diffraction gratings were formed using ion implantation and the effect of local melting. The dynamics of diffraction during and after the light pulse irradiation was studied.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A study was made of the formation of the angular distribution of laser radiation in resonators with retroreflecting mirrors. The exchange lasing was investigated and methods of suppressing it were considered. The dynamic and static optical inhomogeneities were compensated in the active medium and in the optical channel. This reduced the divergence of the output radiation by a factor of 5–10. Intracavity beam control was achieved and complex angular distributions of specified configuration were formed. Self-guidance of the radiation on a mirror target within an angle of 30 µrad was attained.

1. The addition of zinc (up to 1.5%) increases the resistance of deformed aluminum-magnesium alloys containing 7–8% Mg, 0.2% Mn, and small amounts of Ti, Zr, and Be to stress corrosion. 2. The increase of the resistance of aluminum-magnesium alloys to stress corrosion as the result of the addition of zinc is due to a complete and uniform decomposition of the solid solution.

In the years of the rising threat of fascist aggression, the Soviet Union, which had advanced the widely known principle "peace is indivisible," made every effort to establish a system of collective security in Europe. However, the "Western democracies" were deaf to the appeals of the USSR. Things were also unquiet on our Far Eastern frontiers. The Japanese invasions of Manchuria, and then of North and Central China, were accompanied by provocations against the Soviet Union by the Japanese military. The Soviet Union was compelled to strengthen its defense capacity by all possible means and to raise the battle-readiness of the Workers' and Peasants' Red Army. The Central Committee of the Communist Party and the Soviet government, taking into consideration the growing danger of war, did everything necessary to strengthen the Red Army and Navy. The Armed Forces were given the task of being prepared to repulse, at any moment, infringements by imperialist powers upon the sovereignty and territorial inviolabili...

1. The most promising conductor alloys were the binary ones with 0.12% Cr or 0.2% Zr and the trinary alloys with 0.2% Cr, 0.15% Cd or 0.15% Cr and 0.10% Zr. Their room temperature yield strength was 16–23 and the tensile strength 29–36 kg/sq. mm, the elongation, 21–24% and the electrical conductivity, 88–95% of that of plain M0 copper. 2. This property level remained stable after heating at 200°C/1000 hrs. 3. A yield strength of 14–18 kg/sq.mm, a tensile strength of 20–31 kg/sq.mm and an elongation of 20–29% were retained at 220°C. 4. For full-scale trials, the alloy of copper M0 with 0.15–0.3% Cr should be considered first. 5. For heavy-duty conductor elements for service at 250–350°C, an alloy of M0 copper with 0.15–0.2 Cr and 0.1–0.2 Zr is best.

The surface heat flux may be deduced from the time course of the temperature within a body.