Investigation of LiFeAs by means of "Break-junction" Technique

In our tunneling investigation using Andreev superconductor - normal metal - superconductor contacts on LiFeAs single crystals we observed two reproducible independent subharmonic gap structures at dynamic conductance characteristics. From these results, we can derive the energy of the large superconducting gap $\Delta_L=(2.5 \div 3.4)$ meV and the small gap $\Delta_L=(0.9 \div 1)$ meV at $T = 4.2$ K for the $T_C^{local} \approx (10.5 \div 14)$ K (the contact area critical temperature which deviation causes the variation of $\Delta_L$). The BCS-ratio is found to be $2\Delta_L/k_BT_C = (4.6 \div 5.6)$, whereas $2\Delta_S/k_BT_C \ll 3.52$ results from induced superconductivity in the bands with the small gap.Comment: 7 pages, 5 figures. Published in Pis'ma v ZhETF 95, 604-610 (2012

АТРИОСЕПТОСТОМИЯ С ИМПЛАНТАЦИЕЙ ФЕНЕСТРИРОВАННОГО ОККЛЮДЕРА ПРИ ИДИОПАТИЧЕСКОЙ ЛЕГОЧНОЙ ГИПЕРТЕНЗИИ

Introduction. Pulmonary arterial hypertension (PAH) is a rare disease of unknown etiology, characterized by increased resistance of pulmonary vessels, which leads to right ventriculae heart failure and, eventually, death. At the same time, according to the literature, it has been established that the presence of an atrial septum defect in patients with idiopathic PAH (iPAH), is accompanied by a longer life expectancy, improves its quality and is the prevention of sudden death due to the development of a pulmonary hypertensive crisis. We decided to perform an operation to create an atrial septum communication (ASC) in patients with iPAH.Materials and methods. Clinical cases showed efficiency in creating interatrial septum fenestration by implantation of intentionally fenestrated occluder in patients with PAH.Results. It was in studies revealing that the advantage of this method as compared to others is close good fixation of the device on interatrial baffle which reduces possibility for the device to migrate from fixed position in the heart cavity and to reduce intra-operative complication. After implantation of fenestrated occluder the patients showed significant improvement of life quality: decrement of breathlessness, higher tolerance to physical exertion, less swelling in lower limbs, absence of syncopal condition. Such procedure perhaps prolongs life time.Conclusion. Implantation of fenestrated occluder, modified in intra-operative conditions, can be an adequate method to help patients with iPAH, under conditions of unavailability of special devices in the market. Введение. Легочная артериальная гипертензия (ЛАГ) является прогрессирующим смертельным синдромом, характеризующимся повышенным сопротивлением легочных сосудов, что приводит к правосторонней сердечной недостаточности и в итоге — смерти. Вместе с тем было доказано, что наличие открытого овального окна у больных с идиопатической легочной артериальной гипертензией (иЛАГ) сопровождается большей продолжительностью жизни и значительно более высоким ее качеством. Это является обоснованием исследований по созданию межпредсердного сообщения (МПС) у больных с иЛАГ. Цель создания адекватного МПС — профилактика внезапной смерти вследствие развития легочно-гипертензионного криза.Материалы и методы. На клинических случаях продемонстрирована эффективность cоздания межпредсердного сообщения путем имплантации намеренно фенестрированных окклюдеров пациентам с ЛАГ.Результаты. Установлено, что преимуществом данного метода перед другими является плотная хорошая фиксация устройства на межпредсердной перегородке, что уменьшает возможность миграции устройства из фиксированного положения в полости сердца и интраоперационных осложнений. После имплантации фенестрированного окклюдера у пациентов наблюдалось значительное улучшение качества жизни: снижение одышки, повышение толерантности к физической нагрузке, уменьшение отеков нижних конечностей, отсутствие синкопальных состояний. Данная процедура предположительно способствует увеличению продолжительности жизни.Заключение. Имплантация фенестрированного окклюдера, модифицированного в интраоперационных условиях, может быть адекватным методом помощи пациентам с иЛАГ в условиях недоступности специальных устройств на рынке.

Synthesis of γ-, δ-, and ε-Lactams by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)iminoesters

Highly enantiomerically enriched γ- and δ-lactams have been prepared by a simple and very efficient procedure that involves the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)iminoesters followed by desulfinylation of the nitrogen atom and spontaneous cyclization to the desired lactams during the basic workup procedure. Five- and six-membered ring lactams bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and ee’s up to >99%. A slight modification of the procedure also allowed the preparation of ε-lactams in good yields and very high enantioselectivities. Both enantiomers of the final lactams could be prepared with equal efficiency by changing the absolute configuration of the sulfinyl chiral auxiliary

ANALYSIS OF LAYOUT SOLUTIONS OF ELECTROLYSIS SHOP OF HYDROGEN SUPERSTRUCTURE TAKING INTO ACCOUNT THE RELIABILITY AND EXPLOSION RISK

The article considers the layout solutions of the electrolysis shop of the hydrogen superstructure outside the territory of the nuclear power plant. To do this, an annual risk assessment was carried out taking into account the reliability and explosion risk for 1-4, 8 and 16 separate electrolysis shops installed on the site of the hydrogen superstructure. When taking into account equipment breakdowns, with possible explosions and fires in electrolysis plants, the risk due to fires and explosions was several times lower than the risk associated with equipment failures. Calculations showed that the transfer of electrolysis plants to increased hydrogen productivity in the event of failure of one of the cells is the best option in comparison with the reduction in the generation of electricity at the steam turbine installation of the hydrogen superstructure

Professional Activity of A Patronage Nurse in Reproductive Health

One of the most important issues in the world today is reproductive health and related diseases. World statistics: According to experts, one of the main reasons for the rapid growth of the population is the high number of unwanted pregnancies. 2 out of 5 fetuses in the world are unwanted, about 20 million teenage girls become mothers every year and about 6 million ends in abortion. Mortality from pregnancy and childbirth complications - 500 thousand per year. Infant mortality - 9.6 million. The number of abortions per year is 40-60 million. Patronage nurses are the mainstay of reproductive health

Optimization of the operating conditions of gas-turbine power stations considering the effect of equipment deterioration

\u3cp\u3eIn recent years in most power systems all over the world, a trend towards the growing nonuniformity of energy consumption and generation schedules has been observed. The increase in the portion of renewable energy sources is one of the important challenges for many countries. The ill-predictable character of such energy sources necessitates a search for practical solutions. Presently, the most efficient method for compensating for nonuniform generation of the electric power by the renewable energy sources—predominantly by the wind and solar energy—is generation of power at conventional fossil-fuel-fired power stations. In Russia, this problem is caused by the increasing portion in the generating capacity structure of the nuclear power stations, which are most efficient when operating under basic conditions. Introduction of hydropower and pumped storage hydroelectric power plants and other energy-storage technologies does not cover the demand for load-following power capacities. Owing to a simple design, low construction costs, and a sufficiently high economic efficiency, gas turbine plants (GTPs) prove to be the most suitable for covering the nonuniform electric-demand schedules. However, when the gas turbines are operated under varying duty conditions, the lifetime of the primary thermostressed components is considerably reduced and, consequently, the repair costs increase. A method is proposed for determination of the total operating costs considering the deterioration of the gas turbine equipment under varying duty and start–stop conditions. A methodology for optimization of the loading modes for the gas turbine equipment is developed. The consideration of the lifetime component allows varying the optimal operating conditions and, in some cases, rejecting short-time stops of the gas turbine plants. The calculations performed in a wide range of varying fuel prices and capital investments per gas turbine equipment unit show that the economic effectiveness can be increased by 5–15% by varying the operating conditions and switching to the optimal operating modes. Consequently, irrespective of the fuel price, the application of the proposed method results in selection of the most beneficial operating conditions. Consideration of the lifetime expenditure included in the optimization criterion enables enhancement of the operating efficiency.\u3c/p\u3

THE EFFICIENCY OF COMBINED-CYCLE CHP PLANT WITH VARIABLE ELECTRIC LOADS, TAKING INTO ACCOUNT THE WEAR AND TEAR OF EQUIPMENT

The economic efficiency of attracting CHPPs to cover the variable zone of daily electrical load schedules was investigated. The estimation of resource and economic performance of combined -cycle HPPs using the example of PGU-450T taking into account equipment wear under different operating conditions in the daily and weekly sections and different composition of the operating equipment has been performed and optimal load regimes have been determined