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971.
氮蒽衍生物的分子第一超极化率的理论研究 总被引:1,自引:1,他引:0
用HF/6-31G(d)//CPHF/6-31G(d)方法获得了氮蒽衍生物分子的优化结构和分子第一超极化率.结果表明,在氮蒽的4位取代推电子基,11位取代吸电子基而得到的衍生物有相对较大的第一超极化率.苯环上取代基的种类、HOMO-LUMO的能隙及N1原子上的孤对电子对分子第一超极化率都有较大的影响.另一方面,设计的氮蒽衍生物具有较好的透光性和热稳定性,是一类具有潜在的应用价值的非线性光学材料. 相似文献
972.
First China ocean reflection experiment using coastal GNSS-R 总被引:4,自引:0,他引:4
Wang Xin Sun Qiang Zhang XunXie Lu DaRen Shao LianJun Hu Xiong Ruffini Giulio Dunne Stephen Francois Soulat 《科学通报(英文版)》2008,53(7):1117-1120
It is a new way for oceanographic remote sensing using the GNSS-Reflection technique. Sea waves, tides and sea surface wind can be obtained by analyzing the direct and reflected GPS signals from sea surface. It has become an advanced field concerned by many researchers. In this paper the first China Ocean Reflection Experiment (CORE) with the coastal GNSS-R in the southeast is reported and the method to retrieve oceanographic parameters with the direct and reflected GPS signals is studied. The primary retrievals of Significant Wave Height (SWH) are presented and also compared with the measurements from Ultrasonic Wave Gauge (UWG) in situ. 相似文献
973.
秋季珠江口地区海风对城市群空气污染的影响 总被引:4,自引:0,他引:4
根据2004年10月珠江三角洲大气边界层和空气污染物观测资料,分析了位于城市群下风向的珠江口地区的海风对珠江三角洲城市群空气污染的影响。结果表明,秋季珠江口地区海风将抑制城市群空气污染物向下风向输送,而导致城市群空气污染物在向下风向“迁移”过程中“减速”或在城市群短期“堆积”,使城市群空气污染物浓度随海风的出现显著上升,珠江口地区出现海风日城市群空气污染物日平均和日最高浓度与非海风日相比上升了2到4倍;而珠江口地区空气污染物浓度随海风的出现而降低。 相似文献
974.
马克思主义与人道主义有着本质的区别,马克思主义决不能归结为人道主义,事实上马克思主义实现了对人道主义形而上学传统的历史性超越。文章从历史观角度论述了二者之区别,揭示出历史唯物主义创立的理论和现实意义,为马克思主义的不断发展廓清道路。 相似文献
975.
噪声问题是众多城市环境问题中备受关注的问题之一。在人们需要安静休息的住宅、病人需要静养的医院、学生需要静心学习的教室等,都需要良好的声环境。而随着生产的发展和工业体系的完善,噪声污染也越来越严重。本文依据物理原理,对噪声进入室内的方式进行了分类,并对室内噪声声场分布进行分析,从而提出了一些降低室内噪声的可行性措施。 相似文献
976.
Wang Yong Zhang Xin Shao Xiaofang 《科技信息》2008,(15)
以LabWindows/CVI为开发平台,介绍了某型机载雷达通电的软件模拟设计方法。 相似文献
977.
Shao Jun Jiang Min 《科技信息》2008,(30):224-224
In perspective of relevance theory,translation is regarded as communication. According to relevance theory,communication not only requires encoding,transfer and decoding processes,but also involves inference in addition. As communication,translation decision-making is also based on the human beings’ inferential mental faculty. Concentrating on relevance theory,this paper tries to analyze and explain some translation phenomena in two English versions of Cai Gen Tan——My Crude Philosophy of Life. 相似文献
978.
In this paper, the GRACE Earth’s gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89o inclination can improve effectively the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coefficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89o inclination. Two groups of GRACE individually exploiting 89o+(82o-84o) inclinations are the optimal combination of the Earth’s gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exploiting 89o and 83o inclinations is averagely 2 times higher than the accuracy of a group of GRACE exploiting 89o inclination. 相似文献
979.
In this paper, the GRACE Earth's gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89° inclination can effectively improve the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coef- ficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89° inclination. Two groups of GRACE individually exploiting 89° + (82°-84°) inclinations are the optimal combination of the Earth's gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exoloiting 89° and 83° inclinations is averagely two times higher than the accuracy of a group of GRACE exploiting 89~ inclination. 相似文献
980.
High energy efficiency and energy density, together with rapid refuelling capability, render fuel cells highly attractive for portable power generation. Accordingly, polymer-electrolyte direct-methanol fuel cells are of increasing interest as possible alternatives to Li ion batteries. However, such fuel cells face several design challenges and cannot operate with hydrocarbon fuels of higher energy density. Solid-oxide fuel cells (SOFCs) enable direct use of higher hydrocarbons, but have not been seriously considered for portable applications because of thermal management difficulties at small scales, slow start-up and poor thermal cyclability. Here we demonstrate a thermally self-sustaining micro-SOFC stack with high power output and rapid start-up by using single chamber operation on propane fuel. The catalytic oxidation reactions supply sufficient thermal energy to maintain the fuel cells at 500-600 degrees C. A power output of approximately 350 mW (at 1.0 V) was obtained from a device with a total cathode area of only 1.42 cm2. 相似文献