共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
《电子产品可靠性与环境试验》2005,23(B12):F0004
50年的历史,凝聚了几代人的心血和汗水;今日的成就,饱含了几代人的智慧和辛劳。今天,我们纪念建所50周年,就是要回顾历史,总结经验,共谋发展,继承前辈艰苦创业、甘于奉献的优秀品德,发扬“同心、求实、进取”的五所精神,体现赛宝人积极向上的精神风貌,让赛宝承传五所历史,百尺竿头,更进一步,与社会各界共同创造中国信息产业辉煌的明天! 相似文献
4.
5.
6.
7.
8.
据台湾媒体报道,台湾“中科院”研制的雄风2E巡航导弹,已突破关键技术,正式试射成功。雄风2E巡航导弹,射程可达1000km,能涵盖大陆东南沿岸重要军事目标。未来将量产部署。巡航导弹试射成功,应在今年三月以前,台“国防部长”李杰亦亲自南下九鹏导弹基地视导,并全程观看。据了解,雄风巡航导弹试射当日,天气晴朗,导弹朝绿岛方向海域发射,飞行超过500km,并在海平面上,仿真攻击地貌与障碍物,最后顺利命中目标。 相似文献
9.
10.
我家离单位比较远,要坐很久公车,路上很无聊,原来习惯买份报纸看看,开通了3G以后,打开新闻网站,新闻速度比报纸快多了,很多新闻都是以滚动方式展现,而且有些还有视频直播,直观、高效,对我来说,报纸几乎没有存在的意义。 相似文献
11.
Fausone A. Moncalvo A. Tosco F. 《Selected Areas in Communications, IEEE Journal on》1986,4(4):605-611
Studies are being carried out in Italy concerning the strategy for the introduction in the 1990's of optical fiber systems in the distribution network, in order to supply customers with broad-band services (in particular with video services). This paper deals with some of the main choices that are being done, in particular in view of a field trial which is planned in Rome in 1988. 相似文献
12.
利用2007-2013年的COSMIC掩星数据,分析了E区与F区电离层闪烁的变化特征.发现用闪烁出现频次、闪烁发生率以及闪烁强度来表征的电离层闪烁出现规律比较相似.E区电离层闪烁在夏季半球的中纬地区最强,其次是春秋季的低纬地区和冬季半球.就经度分布来说,春秋季E区电离层闪烁呈四波结构.对F区电离层闪烁来说:南美-大西洋扇区在12月至点最为显著;非洲和太平洋扇区在6月至点最为显著;大西洋扇区在春秋分季最为显著.极区也出现中等强度的闪烁,尤其在南半球的90°E~180°E扇区较为显著.高纬E区电离层闪烁强度随太阳活动的增强而增强,而低纬和南半球的中纬E区闪烁随太阳活动的增强而减弱.高纬和低纬F区闪烁随太阳活动的增强而增强,而中纬F区电离层闪烁对太阳活动无显著依赖关系.对于赤道区来说,北半球60°W~60°E经度区闪烁强度随太阳活动的变化最为显著,其次是南半球60°E~210°E附近;而对于高纬地区来说,F区闪烁强度随太阳活动的变化最为显著的区域在南半球60°E~210°E附近. 相似文献
13.
M. I. Makoviichuk 《Russian Microelectronics》2000,29(4):219-234
Flicker noise spectroscopy in disordered semiconductors is gaining wide acceptance both in physical investigation and in analysis
of various microelectronics processes. Its successful use as a diagnostic tool in microtechnology is a result of advances
in fundamental studies of flicker noise in semiconductors with disordered structure. In this work, we systematize experimental
data for flicker noise phenomena in disordered semiconductors, specifically, in ion-implanted silicon 相似文献
14.
《Communications Surveys & Tutorials, IEEE》2009,11(4):1-2
Welcome to the fourth issue of 2009 of the IEEE Communications Surveys and Tutorials. Paper in this issue survey the research effort in several areas such mobility in Wimax, mobility models in VANET, handoff in cellular networks, admission control in MANETS, physical impairments in optical networks, physical layer issues in the 802.11n standard as well as jamming in wireless sensor networks 相似文献
15.
《Telematics and Informatics》2004,21(1):25-47
The approach in the paper is that institutions matter, i.e. perceptions, norms, values, role patterns and organisations that shape conduct. This approach is used in seeking to explain the differences in telecom developments in Mozambique and Zimbabwe. The question in the paper is why telecom developments in Mozambique have been faster than in Zimbabwe even though Zimbabwe had a better starting point in terms of economic development than Mozambique. 相似文献
16.
Modulation of absorption of middle-infrared radiation in double tunneling-coupled quantum wells in longitudinal electric fields is studied. A specific feature of the quantum wells is the small separation in energy between the two lower levels. As a consequence, the levels may exhibit “anticrossing” even in low transverse electric fields. An interpretation of the change in intersubband absorption is suggested. The interpretation is based on the assumption that a transverse electric-field component may appear in the structure. The change in the absorption coefficient is calculated taking into account the redistribution of electrons between size-quantization subbands and the changes in the temperature of electrons in the subbands in the longitudinal electric field, as well as the changes in the optical matrix elements, the energies of transitions, and the concentrations of electrons in the subbands in the transverse electric field. The possibility of using the structure for the efficient modulation of middle-infrared light with the photon energy 136 meV is shown. 相似文献
17.
T S Bobrova I N Kriukova Iu V Chuev V I Rotenberg T V Golovkina 《Eksperimental?nai?a onkologii?a》1988,10(6):35-39
A newly detected antigen common for transplantable HeLa-like cell lines and human gastric mucosa has been revealed in all parts of the stomach and in highly differentiated gastric adenocarcinomas in humans. It is localized in the basal area of tall columnar cells in the mucosa and has one immunologically active subunit with molecular weight of 39 kDa. The antigen differs from the other earlier described gastrointestinal antigens in its localization in the organs and cells and in other characteristics. 相似文献
18.
N. A. Torkhov 《Semiconductors》2011,45(7):935-943
It is shown that changes in device characteristics and an increase in the light-to-electrical energy conversion efficiency
in metal-semiconductor Schottky barrier contacts are associated with a peripheral electric field built into the contact. For
contacts with longer perimeters, variations in device characteristics and the light-to-electrical energy conversion efficiency
are significantly larger. Since the photovoltage and peripheral electric fields in the contact region are codirected with
the intrinsic electric field of the space-charge region, contact illumination results in a larger increase in the “dead” zone
in forward portions of current-voltage characteristics, a larger decrease in the effective Schottky barrier height, and an
increase in the field electron emission. An increase in the reverse field emission under photovoltage leads to an increase
in the recombination current in the space-charge region, which provides dc photocurrent flow in the circuit. 相似文献
19.
An attempt is made to determine if investment in R&D and the hiring of college-educated employees result in a higher rate of inventions. The relationship between the input of R&D and inventive output is studied in two samples of Japanese factories, 34 in 1982 and 44 in 1970. These results are compared with findings in a parallel American study. The correlations between R&D and inventive output are similar in Japan and America in the 1980s, despite some differences in the management of innovation in the two nations. Moreover, the most Westernized subsample of Japanese firms in the 1970s had correlations between R&D and invention similar to those observed in the American study. Thus, it is concluded that some degree of convergence may be taking place in R&D management strategies in the two nations 相似文献
20.
Potvin Alfred R. Long Francis M. Webster John G. Jendrucko Richard J. 《IEEE transactions on bio-medical engineering》1981,(1):22-28
During the 1979-1980 academic year a two-page questionnaire on biomedical engineering education was sent to 251 engineering schools. 71 schools indicated that they had degree programs and an additional 35 indicated that they had official minor or option programs, 107 did not have a program, and 38 did not respond. For schools offering degrees in biomedical engineering, there were 2859 students enrolled in 37 B.S. programs, 830 students in 48 M.S. programs, and 469 students in 41 Ph.D. programs. Options or minors in biomedical engineering with a degree in another engineering discipline were available at the B.S. level at 41 schools, at the M.S. level at 42 schools, and at the Ph.D. level at 34 schools. Over the past two years, schools offered 109 courses in biomedical instrumentation, 74 in computers in medicine, 162 in physiological systems/modeling, 60 in biomechanics, 47 in biomaterials, 33 in hospital internship, 23 in clinical engineering, 9 in biomedical engineering lab, and 67 in other areas. During the academic year 1978-1979, schools awarded 464 B.S. degrees, 249 M.S. degrees, and 107 Ph.D. degrees in biomedical engineering. Of these graduates, 253 found jobs in industry, 23 in government, 35 in academia, and 66 in hospitals or clinics; 100 went to medical school, 96 to biomedical engineering graduate schools, and 57 to other graduate or professional schools. 相似文献