INVESTIGATION OF PASSIVATION OF SURFACE STATES OF SINGLE CRYSTALLINE SILICON IN HETEROSTRUCTURES WITH AN INTEGRATED THIN AMORPHOUS LAYER

This work presented in this publication is a continuation of works [1] and [2]. We have shown that in solar cells of the HIT structure, when the thickness of the embedded amorphous layer increases, the efficiency of the solar cell increases, but to a certain point of maximum. The increase in characteristics is due to an increase in the lifetime of non-basic charge carriers in a crystalline silicon substrate. This behaviour of the system can be explained by better passivation of surface States on the silicon substrate. The decrease in the efficiency of the solar cell after reaching the maximum is due to the increase of the resistance structure, which with a point contributes more to the characteristics of the solar cell than the contribution from the passivation of surface states. Using the PECVD method, amorphous silicon films with a thickness of 7, 30 and 50 nm were grown on a single-crystal commercial silicon substrate on both sides. Then, the lifetime of non-basic charge carriers was measured using the contactless Sinton method on these structures. Further, the samples were examined by photoluminescence at room temperature. Using this method, it was possible to obtain the dependence of the concentration of non-equilibrium charge carriers on the intensity of photoluminescence radiation. These dependences showed that the intensity is lower on samples with a lower thickness of amorphous silicon than in samples with a higher thickness of the amorphous layer. The detailed results of this work were first presented by the corresponding author in his dissertation [3], the theses of the work were presented at the conference of young scientists of KazNU [4] and only now the results are published as a full-fledged article in the journal.

Influence of Rectifier Nozzles on the Flow Distribution Characteristics of Parallel Pipes

The inhomogeneous distribution of parallel pipe flow leads to difficulty in the efficient and reliable operation of fluid power equipment. In view of this, a new type of rectifier nozzle has been proposed in parallel pipelines. Numerical simulation and experimental studies were used to reveal the influence of the rectification nozzle on the flow distribution characteristics. The hydraulic characteristics of the parallel pipelines with and without rectifier nozzles were compared and analyzed. The effects of the temperature and inlet flow on the flow uniformity were studied. The results showed that the initial temperature had little effect on the flow distribution of parallel pipelines, and the flow rates of the branches were not much different. The inlet flow had great influence on the distribution characteristics of the parallel pipelines, but the rectifier nozzles changed the local resistance structure and pressure distribution at the shunt, thereby improving the non-uniformity of the flow distribution of the parallel pipelines, and the maximum difference between the two pipes was optimized from 28.89 t/h (20.3%) to 2.2 t/h (1.5%). The rectifying nozzle could distort the flow field of each branch during the split, making the distribution of flow rate and flow state more uniform and stable. At high inlet fluid temperatures, cavitation could occur under the pressure drop of the nozzle, and partial cavitation had little effect on the flow distribution.

Earthquake Resistant Design

In the long history of mankind's existence, nature's forces have influenced human existence to a great extent. Of all natural disasters, the least understood and most destructive are earthquakes. Their claim of human lives and material losses constantly force people to search for better protection, still a great challenge for engineers and researchers worldwide. Although important progress has been done in understanding seismic activity and developing buildings technology, a better way of protecting buildings on large scale is still in search. The essential features of earthquake resistance structure are stable foundation design, regularity, ductility, adequate stiffness, redundancy, and ruggedness. The chapter focuses on increasing the knowledge dictum of earthquake resistant design and discusses the various sorts of issues and challenges. It also presents a wide view on optimization techniques that are required to be done in the latest technology currently in practice so as to achieve the optimum design techniques.

MORPHOLOGICAL CHARACTERISTICS OF CELLULAR AND TISSUE REACTIONS IN TUBERCULOUS INFECTIONS CAUSED BY DRUG-RESISTANT STRAINS

One of the main causes of the epidemic of tuberculosis in our country is the spread of strains of Mycobacterium tuberculosis, which are multiple and extensively drug-resistant. This serious drug resistance structure is explained by the wide circulation of strains of mycobacteria of the genetic family Beijing in the Russian Federation. Each of the stages of such an evolving infectious process is characterized by certain tissue and cellular reactions, shifts in metabolism and functional state of cells involved in the inflammatory process. The literature review covers the biological properties of this strain, the morphology of mycotuberculous inflammation from the position of cell-tissue reactions, the role of the vascular bed in this inflammation, and the study of the functional activity of cellular elements in the zone of tuberculous inflammation with the help of immunohistochemical study

A wideband CMOS single-ended low noise amplifier employing negative resistance technique

A wideband common-gate CMOS low noise amplifier with negative resistance technique is proposed. A novel single-ended negative resistance structure is employed to improve gain and noise of the LNA. The inductor resonating is adopted at the input stage and load stage to meet wideband matching and compensate gain roll-off at higher frequencies. Implemented in a 0.18 [Formula: see text]m CMOS technology, the proposed LNA demonstrates in simulations a maximal gain of 16.4 dB across the 3 dB bandwidth of 0.2–3 GHz. The in-band noise figure of 3.4–4.7 dB is obtained while the IIP3 of 5.3–6.8 dBm and IIP2 of 12.5–17.2 dBm are post-simulated in the designed frequency band. The LNA core consumes a power dissipation of 3.8 mW under a 1.5 V power supply.