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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Roberts D.A. Becchetti F.D. Ashktorab K. Stewart D. Janecke J. Gustafson H.R. Dueweke M.J. 《IEEE transactions on nuclear science》1992,39(4):532-535
Deuterated scintillators (NE230) can provide, without time-of-flight, usable neutron energy spectra for neutrons E n⩾1 MeV. The authors have assembled and calibrated several of these detectors and used them in experiments searching for d+d fusion-neutron emission (E n, 2.5 MeV) in Pd+D 2O electrolysis and Ti+D2 adsorption at LN temperatures. The detectors yielded direct fusion-neutron spectra and set limits in the Pd+D and Ti+D experiments of <7×10-24 fusion n/s/dd pair and <3×10-24 fusion n/s/dd pair respectively. In addition, these detectors have been used for in-beam accelerator experiments requiring coincidence between fast neutrons and scattered ions 相似文献
993.
I. R. Tatur D. A. Yakovlev I. A. Timokhin L. R. Berezovskii G. B. Prigul'skii V. A. Lazarev V. N. Sergeev 《Chemical and Petroleum Engineering》1992,28(10):623-627
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 10, pp. 29–31, October, 1992. 相似文献
994.
An averaging circuit model is developed for the class E resonant DC-DC converter regulated at a fixed switching frequency. The regulation is achieved by use of an auxiliary switch. The model is obtained based on the circuit analysis using the Fourier series expansion. Steady-state and small-signal dynamic analysis is presented, which reveals that the DC output is well controlled by the control angle of the auxiliary switch and that there exists a right-half-plane zero in the control-to-output transfer function. The analysis results are verified by the experiments 相似文献
995.
In this work 23 month old rats were fed for 200 days with different protein diets (NT-diet: 19% protein, 72% of animal origin and LP-diet: 8.8% protein exclusively of vegetable origin). Some metabolic parameters and lifespan (on the base of a 50% death-rate) were determined. The relations of the liver free amino acids glycine + alanine and tyrosine + phenylalanine + branched chain amino acids and the ratio of phenylalanine/tyrosine were determined to be higher in the LP-group. Phenylalanine in liver and urea concentrations in liver and serum were lower in the LP-group. Furthermore the dopamine or serotonin levels were significantly lower in lateral and medial or lateral regions of the hypothalamus respectively in LP-diet fed rats. The norepinephrine content was not modified by the diets. The median lifespan of 23 month old rats was higher by 24% following LP-treatment. These results suggest that the protein component (amino acids) of different diets may modify metabolic parameters and lifespan of animals by mechanisms in which the central regulation may be involved. 相似文献
996.
Al-Hemyari K. Aitchison J.S. Ironside C.N. Kennedy G.T. Grant R.S. Sibbett W. 《Electronics letters》1992,28(12):1090-1092
The first observation is reported of ultrafast all-optical switching in an integrated asymmetric Mach-Zehnder interferometer, using the nonresonant nonlinearity in Ga/sub 0.82/Al/sub 0.18/As below half the bandgap. A relative switching fraction of more than 80% has been achieved using 330 fs pulses at around 1.55 mu m from a coupled-cavity mode-locked colour centre laser.<> 相似文献
997.
D. Trmouilles G. Bertrand M. Bafleur F. Beaudoin P. Perdu N. Guitard L. Lescouzres 《Microelectronics Reliability》2003,43(1):71-79
The number of circuit design iterations due to electrostatic discharge (ESD) failures increases with the complexity of VLSI technologies and their shrinking. In this paper, we show how TCAD and ESD SPICE modeling can be used to solve ESD protection issues in an analog CMOS technology. 相似文献
998.
V. S. Yamshchikov V. L. Shkuratnik K. G. Lykov V. M. Farafonov 《Journal of Mining Science》1991,27(2):100-103
Mining Institute, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 26–29,
March–April, 1991. 相似文献
999.
On the capacity of a cellular CDMA system 总被引:37,自引:0,他引:37
Gilhousen K.S. Jacobs I.M. Padovani R. Viterbi A.J. Weaver L.A. Jr. Wheatley C.E. III 《Vehicular Technology, IEEE Transactions on》1991,40(2):303-312
It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity 相似文献
1000.
L.M. MARERO E.M. PAYUMO A.R. AGUINALDO S. HOMMA O. IGARASHI 《Journal of food science》1991,56(1):270-271
Four weaning food formulations prepared from 70% 72-hr germinated rice/corn and 30% 48-hr germinated mungbean/cowpea were studied for tocopherol constituents and compared to ungerminated controls. γ-TocopheroIs were the major constituents of the mungbean-supplemented samples. The cowpea-supplemented foods contained a predominance of δ-tocopherols followed closely by γ-tocopherols, α-Tocopherols were comparatively higher in corn- than in rice-formulations. Tocopherols in the weaning foods decreased due to germination especially the γ-tocopherols of germinated corn-mungbean. 相似文献