检索结果-南通市图书馆

The Generalized Newton’s Law of Gravitation Versus the General Theory of Relativity

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Physics 2012年第9期3卷 1231-1235页

作者： Arbab Ibrahim Arbab Department of Physics Faculty of Science University of Khartoum Khartoum Sudan

Einstein general theory of relativity (GTR) accounted well for the precession of the perihelion of planets and binary pulsars. While the ordinary Newton law of gravitation failed, a generalized version yields similar results. We have shown here that these effects can be accounted for as due to the existence of gravitomagnetism only, and not necessarily due to the curvature of space time. Or alternatively, gravitomagnetism is equivalent to a curved space-time. The precession of the perihelion of planets and binary pulsars may be interpreted as due to the spin of the orbiting planet (m) about the Sun (M). The spin (S) of planets is found to be related to their orbital angular momentum (L) by a simple formula, viz., S (m/M)L.

关键词： General Relativity Gravitomagnetism Perihelion Precession of Planets and Binary pulsars Origin of planetary Spin

CORRELATIVE ANALYSIS BETWEEN SOUTHERN OSCILLATION AND ACTIVITIES OF WEST PACIFIC HIGH DURING CHINESE RAINY SEASON

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1988年第9期33卷 753-756页

作者：徐群 Jiangsu Meteorological Institute Nanjing

Southern Oscillation Indices (SOI)is the major factor reflecting the different phases of tropical air-sea interaction of planetary scale. It is well known that SOI influence greatly the low frequency fluctuation of tropical and subtropical circulations. Now, by means of two kinds of monthly SOI data in the term of more than 30 years, the author analyzes its lagging relation with some characteristical parameters of monthly WPH during the rainy season of China and finds out a significant

关键词： tropical typhoon season planetary rainy fluctuation northward reflecting landing autumn

Gearbox Scheme in High Temperature Reactor Helium Gas Turbine System

在线全文

学校读者我要写书评

暂无评论

World Journal of Nuclear Science and Technology 2012年第3期2卷 85-88页

作者： Sheng Liu Xuanyu Sheng Qinghuangdao School North East Petroleum University Qinghuangdao China xuanyu@***

Helium Turbine is used in High Temperature Reactor Helium Gas Turbine (HTR-GT) system, by which the direct helium circulation between the reactor and turbine generator system will come true. Between helium turbine and generator, there is gearbox device which reduces the turbine rotation speed to normal speed required by the generator. Three optional gearbox schemes are discussed. The first is single reduction cylindrical gearbox, which consists of one high speed gear and one low speed gear. Its advantage is simple structure, easy to manufacture, and high reliability, while its disadvantage is large volume and misalignment of input and output axle. The second is planetary gear mechanism with static planet carrier. The third is planetary gear mechanism with static internal gear. The latter two gearbox devices have similar structure. Their advantage is small volume and high reduction gear ratio, while disadvantage are complicated structure, many gears, low reliability and low mechanical efficiency.

关键词： High Temperature Gas Cooled Reactor Gear Box planetary Gear

有限元/接触法计算含滚动元件轴承的行星齿轮的准静态相应、齿根应力和行星轮负载均衡

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

有限元/接触法计算含滚动元件轴承的行星齿轮的准静态相应、齿根...

作者：吴越上海交通大学

学位级别：硕士

该研究运用最前沿的有限元/接触方法研究了含滚动元件轴承的行星齿轮的准静态相应、负载均衡和齿根应力。有限元/接触方法在过去的研究中被广泛运用于精确计算齿轮间的弹性接触。大部分已知的关于行星齿轮的研究使用集中刚度矩阵代替含... 详细信息

该研究运用最前沿的有限元/接触方法研究了含滚动元件轴承的行星齿轮的准静态相应、负载均衡和齿根应力。有限元/接触方法在过去的研究中被广泛运用于精确计算齿轮间的弹性接触。大部分已知的关于行星齿轮的研究使用集中刚度矩阵代替含滚动元件轴承。该研究首先依据真实轴承产品建立了二维独立轴承模型,并通过准静态分析探究独立轴承模型的刚度和形变特性。该模型探明了轴承内滚动元件的运动学轨迹导致的轴承刚度和偏移的周期性变化,和载荷与径向间隙变化导致的非线性刚度变化。随后,该研究建立了基于真实直升机应用的二维行星齿轮模型,并在分别应用刚度矩阵轴承模型和接触轴承模型的情况下进行准静态分析。当使用刚度矩阵轴承时,因轴承刚度的非线性特性,模型对行星齿轮中央部件的部分自由度均值的计算存在显著误差。当使用接触轴承时,模型还捕捉到了由周期性变化的轴承偏移导致的行星架旋转自由度内的低频成分,和由周期性变化的轴承刚度导致的行星轮负载的调制现象。针对载荷和间隙的参数分析表明该低频组分和调制在多种工况下均有显著效应。行星齿轮轴位置误差会造成不均衡的行星轮负载,但该现象对轴承的建模方式并不敏感。最后,该研究建立了基于同一系统的三维行星齿轮模型,并通过静态分析该系统的两个典型状态探究滚动元件轴承对轴承座圈形变、齿根应力、齿接触压力、静态传动误差和行星轮负载均衡的影响。通过对该模型分别应用刚度矩阵轴承模型和接触轴承模型,作者确定了接触轴承模型能够更加准确地计算轴承座圈形变。轴承座圈形变与轴承内滚动元件的协同作用导致齿根应力的最大值及其出现位置在应用不同轴承的模型中存在显著差异。通过调整行星轮的内径,使用刚度矩阵轴承的二维或三维行星齿轮模型能够用于近似求解使用接触轴承的三维行星齿轮内的齿根应力。

关键词： bearings planetary 行星齿轮行星轮轴承座 stiffness 刚度矩阵 clearance 静态分析 Figure

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

真空蒸发、淀积、溅射、氧化与金属化工艺

电子科技文摘 2003年第4期 25-26页

Y2002-63306-307 0307243多硅片 AIX2400G3行星反应器中生长长波长 InP 基材料=InP based materials for long wavelength optoelec-tronics grown in a multiwafer AIX 2400 G3 planetary re-actor[会,英]/Schmitt,T.& Deufel,M.//2001... 详细信息

关键词：淀积金属化真空蒸发 planetary strained MOCVD 金属有机化学玻璃衬底可见光范围化学气相沉积

EXTRATERRESTRIAL GEOLOGY

在线全文

学校读者我要写书评

暂无评论

Abstracts of Chinese Geological Literature 2007年第2期23卷 1-1页

20070747 Ouyang Ziyuan(National Astro- nomical Observatories,Chinese Academy of Sciences,Beijing 100012,China)Advances in the Exploration of the Solar System and Key Aspects of Comparative Planetology (Earth Science F... 详细信息

关键词： Solar Astro reviewing Australia planetary geology

Measure the lunar ionosphere by radio occultation

在线全文

学校读者我要写书评

暂无评论