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排序方式: 共有925条查询结果,搜索用时 15 毫秒
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2.
T. I. Voronina T. S. Lagunova M. P. Mikhailova K. D. Moiseev M. A. Sipovskaya Yu. P. Yakovlev 《Semiconductors》1997,31(8):763-767
Galvanomagnetic phenomena and photoconductivity in broken-gap type-II GaInAsSb/p-InAs heterojunctions with different levels of doping of the solid solution with donor (Te) or acceptor (Zn) impurities have
been investigated. It has been determined that in such structures an electronic channel, which determines the galvanomagnetic
effects in a wide range of doping levels, is present at the heterojunction. A sharp decrease of the Hall mobility was observed
in the experimental heterostructures with a high level of doping of the epitaxial layer with an acceptor impurity. The observed
effect is due to exhaustion of the electronic channel as a result of carrier localization in potential wells at the heterojunction.
Fiz. Tekh. Poluprovodn. 31, 897–901 (August 1997) 相似文献
3.
A. D. Bulanov A. N. Moiseev O. Yu. Troshin V. V. Balabanov D. V. Isaev 《Inorganic Materials》2004,40(6):555-557
High-purity isotopically enriched (99.98% 28Si, 99.57% 29Si, and 99.83% 30Si) silane samples are prepared for the first time. The total hydrocarbon content of the samples is no higher than 0.1–0.3 ppm. The concentration of electroactive impurities in the silicon prepared from the purified monoisotopic silane is below 1015 cm–3. 相似文献
4.
A. V. Chirkov G. G. Denisov A. N. Kuftin V. E. Zapevalov V. I. Malygin M. A. Moiseev S. Yu. Kornishin 《Technical Physics Letters》2007,33(4):350-352
The results of numerical simulation and experimental investigation of a prototype of a megawatt multifrequency gyrotron for controlled thermonuclear fusion facilities are presented. In experiments, the gyrotron has operated at six frequencies in the range 105–152 GHz with small diffraction losses in the internal quasi-optical system and a high Gaussian mode content in the output beam. 相似文献
5.
Optimal control (OC) methodology is used to develop a control policy for a batch-operated solar sludge dryer with ventilation as the dominant control. Batch performance criteria and instantaneous optimization criteria are developed for two economic environments: quota limited and capital limited. The general formulation, as well as simplifications resulting from the multiplicative form of the evaporation (drying) rate model, are presented. The multiplicative form results in a single constant number, called here “control intensity,” which is used to guide the on-line control decisions. These decisions turn out to be independent of the dry solids content (DSC) of the sludge. Further simplification, by assuming a strictly constant weather, is used to demonstrate the general effects of the economic and physical (weather) environment on the solution.
The OC approach is used to address, via simulation under realistic weather conditions, several design, operation, and pricing problems. In particular, the following have been considered: sizing of the ventilation fans, determination of a fair fee for sludge disposal, finding the best final DSC, and evaluating the effect of the price of electricity. Regarding the particular location represented by the data, it has been shown that the installed capacity of the ventilation fans should be increased and that there seems to be sufficient economic incentive for solar drying. 相似文献
The OC approach is used to address, via simulation under realistic weather conditions, several design, operation, and pricing problems. In particular, the following have been considered: sizing of the ventilation fans, determination of a fair fee for sludge disposal, finding the best final DSC, and evaluating the effect of the price of electricity. Regarding the particular location represented by the data, it has been shown that the installed capacity of the ventilation fans should be increased and that there seems to be sufficient economic incentive for solar drying. 相似文献
6.
T. I. Voronina T. S. Lagunova M. P. Mikhaĭlova K. D. Moiseev A. F. Lipaev Yu. P. Yakovlev 《Semiconductors》2006,40(5):503-520
The results of detailed study of the magnetotransport properties of broken-gap type II heterojunctions in a GaInAsSb/InAs(GaSb) system are reported. An electron channel with a high charge-carrier mobility (as high as 50000–60000 cm2/(V s)) is observed and studied for the first time in an isotype broken-gap p-GaInAsSb/p-InAs heterostructure. The effects of electron-channel depletion and semimetal-semiconductor transition in the case of heavy doping of the quaternary alloy with acceptors are studied. Magnetotransport properties at temperatures of 4.2–200 K are studied in detail. Data on the energy spectrum and parameters of two-dimensional charge carriers at the heteroboundary are obtained. It is ascertained experimentally that, depending on the composition, either staggered (at x = 0.85) or broken-gap (at x = 0.95) heterojunctions can be formed in the Ga1?x InxAsySb1?y /GaSb, which is confirmed by theoretical calculations. The anomalous Hall effect and negative magnetoresistance were observed in GaInAsSb/InAs:Mn grown on substrates doped heavily with Mn magnetic acceptor impurity so that the hole concentration was as high as p > 5 × 1018 cm?3; these phenomena are caused by exchange interaction of Mn ions in InAs with high-mobility charge carriers in the electron channel at the heterointerface. 相似文献
7.
A. A. Dabizha L. P. Ivanova V. A. Kotlyarov V. V. Moiseev I. P. Panov G. A. Petropavlovskaya 《Powder Metallurgy and Metal Ceramics》1990,29(8):595-598
Translated from Poroshkovaya Metallurgiya, No. 8(332), pp. 6–9, August, 1990. 相似文献
8.
Scientific-Industrial Association D. I. Mendeleev All-Union Scientific-Research Institute of Metrology. Translated from Atomnaya Énergiya, Vol. 73, No. 6, pp. 502-504, December, 1992. 相似文献
9.
Diana Salikhova Tatiana Bukharova Elvira Cherkashova Daria Namestnikova Georgy Leonov Maria Nikitina Ilya Gubskiy Gevorg Akopyan Andrey Elchaninov Konstantin Midiber Natalia Bulatenco Victoria Mokrousova Andrey Makarov Konstantin Yarygin Vladimir Chekhonin Liudmila Mikhaleva Timur Fatkhudinov Dmitry Goldshtein 《International journal of molecular sciences》2021,22(9)
Transplantation of various types of stem cells as a possible therapy for stroke has been tested for years, and the results are promising. Recent investigations have shown that the administration of the conditioned media obtained after stem cell cultivation can also be effective in the therapy of the central nervous system pathology (hypothesis of their paracrine action). The aim of this study was to evaluate the therapeutic effects of the conditioned medium of hiPSC-derived glial and neuronal progenitor cells in the rat middle cerebral artery occlusion model of the ischemic stroke. Secretory activity of the cultured neuronal and glial progenitor cells was evaluated by proteomic and immunosorbent-based approaches. Therapeutic effects were assessed by overall survival, neurologic deficit and infarct volume dynamics, as well as by the end-point values of the apoptosis- and inflammation-related gene expression levels, the extent of microglia/macrophage infiltration and the numbers of formed blood vessels in the affected area of the brain. As a result, 31% of the protein species discovered in glial progenitor cells-conditioned medium and 45% in neuronal progenitor cells-conditioned medium were cell type specific. The glial progenitor cell-conditioned media showed a higher content of neurotrophins (BDNF, GDNF, CNTF and NGF). We showed that intra-arterial administration of glial progenitor cells-conditioned medium promoted a faster decrease in neurological deficit compared to the control group, reduced microglia/macrophage infiltration, reduced expression of pro-apoptotic gene Bax and pro-inflammatory cytokine gene Tnf, increased expression of anti-inflammatory cytokine genes (Il4, Il10, Il13) and promoted the formation of blood vessels within the damaged area. None of these effects were exerted by the neuronal progenitor cell-conditioned media. The results indicate pronounced cytoprotective, anti-inflammatory and angiogenic properties of soluble factors secreted by glial progenitor cells. 相似文献
10.
Aleksandra A. Ageeva Ilya M. Magin Alexander B. Doktorov Victor F. Plyusnin Polina S. Kuznetsova Alexander A. Stepanov Alexander A. Alekseev Nikolay E. Polyakov Tatyana V. Leshina 《International journal of molecular sciences》2021,22(12)
The study of the L- and D-amino acid properties in proteins and peptides has attracted considerable attention in recent years, as the replacement of even one L-amino acid by its D-analogue due to aging of the body is resulted in a number of pathological conditions, including Alzheimer’s and Parkinson’s diseases. A recent trend is using short model systems to study the peculiarities of proteins with D-amino acids. In this report, the comparison of the excited states quenching of L- and D-tryptophan (Trp) in a model donor–acceptor dyad with (R)- and (S)-ketoprofen (KP-Trp) was carried out by photochemically induced dynamic nuclear polarization (CIDNP) and fluorescence spectroscopy. Quenching of the Trp excited states, which occurs via two mechanisms: prevailing resonance energy transfer (RET) and electron transfer (ET), indeed demonstrates some peculiarities for all three studied configurations of the dyad: (R,S)-, (S,R)-, and (S,S)-. Thus, the ET efficiency is identical for (S,R)- and (R,S)-enantiomers, while RET differs by 1.6 times. For (S,S)-, the CIDNP coefficient is almost an order of magnitude greater than for (R,S)- and (S,R)-. To understand the source of this difference, hyperpolarization of (S,S)-and (R,S)- has been calculated using theory involving the electron dipole–dipole interaction in the secular equation. 相似文献