期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
恒亮度原理失效研究
1
作者 江茂 周少娜 《华南师范大学学报(自然科学版)》 CAS 2007年第2期70-72,92,共4页
早在20世纪中期,人们就发现了在传送黑白图像时,显像管的非线性会引起恒亮度原理失效.本研究也指出:在传送彩色图像时,G-Y解调器的失常也会引起恒亮度原理失效.
关键词 亮度原理 失效 亮度 彩色电视 色解码
下载PDF
最简单的恒流充电器
2
作者 王绍华 《家电维修》 2003年第12期57-57,共1页
关键词 流充电器 负载电阻 原理 电源插头
下载PDF
Several Fundamental Theorems and Conservative Integrals in Quasicrystal Elasticity Theory 被引量:1
3
作者 李显方 孙应飞 范天佑 《Journal of Beijing Institute of Technology》 EI CAS 1998年第3期226-232,共7页
Aim To extend several fundamental theorems of conventional elasticity theory to quasicrystalelasticity theory. Methods The basic governing equations of quasicrystal elasticity theory and Gauss's theorem were appli... Aim To extend several fundamental theorems of conventional elasticity theory to quasicrystalelasticity theory. Methods The basic governing equations of quasicrystal elasticity theory and Gauss's theorem were applied in the derivation. Results and Conclusion The principle of virtual work, Betti's reciprocal theorem and the uniqueness theorem of quasicrystal elasticity theory are proud, and some conservative integrals in quasicrystal elasticty theory are obtained. 展开更多
关键词 quasicrystal elasticity theory conservative integral the principle ofvirtual work Betti's reciprocal theorem the uniqueness theorem
下载PDF
“牟合方盖”研究 被引量:5
4
作者 李宇祎 《雁北师范学院学报》 2003年第5期107-108,112,共3页
我国很早就开始了球体积的研究 ,《九章算术》少广章得出的公式为V球 =9D3 / 1 6 ,三世纪数学家刘徽发现这是错误的 ,他认为球体积应为外切于它的一个牟合方盖的体积 ,所谓“牟合方盖”是两个半径相等的直交圆柱面相贯所围成的立体 .但... 我国很早就开始了球体积的研究 ,《九章算术》少广章得出的公式为V球 =9D3 / 1 6 ,三世纪数学家刘徽发现这是错误的 ,他认为球体积应为外切于它的一个牟合方盖的体积 ,所谓“牟合方盖”是两个半径相等的直交圆柱面相贯所围成的立体 .但刘徽没有直接求出牟合方盖的体积 .二百年后 ,祖冲之父子推得了 。 展开更多
关键词 牟合方盖 祖日 恒原理
下载PDF
大功率弧光放电电源
5
作者 王海燕 马刚立 《郑州工业大学学报》 1997年第2期75-78,共4页
本文主要论述了大功率弧光放电电源的工作原理及其制造过程。
关键词 辉光放电 弧光放电 原理 气体放电 电源
下载PDF
差压式液位测量技术问答(四)
6
作者 汪玉忠 《自动化博览》 2010年第12期109-113,共5页
问吹液式(又称打冲洗液)液位测量方法、组成及特点是什么?吹液俗称打冲洗液,常用冲洗液为油和水,其测量原理、组成与吹气式的测量方法基本相同。也是基于临界压缩比恒流原理,其测量方法和组成如图27所示。阀、二次阀、堵头、差压变... 问吹液式(又称打冲洗液)液位测量方法、组成及特点是什么?吹液俗称打冲洗液,常用冲洗液为油和水,其测量原理、组成与吹气式的测量方法基本相同。也是基于临界压缩比恒流原理,其测量方法和组成如图27所示。阀、二次阀、堵头、差压变送器、引压管和液源等。(1)使用说明①节流元件的孔径,有两种方法确定:一种通过流体力学的计算(本文另有推导);另一种是使用经验数据。从国内外使用经验看,孔径取在φ0.6~φ1.2mm范围, 展开更多
关键词 液位测量技术 差压式 测量方法 临界压缩比 差压变送器 冲洗液 测量原理 原理
下载PDF
Cooling Curve of Strange Star in Strong Magnetic Field
7
作者 WANG Xiao-Qin LUO Zhi-Quan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第11期1255-1257,共3页
In this paper, firstly, we investigate the neutrino emissivity from quark Urca process in strong magnetic field. Then, we discuss the heat capacity of strange stars in strong magnetic field. Finally, we give the cooli... In this paper, firstly, we investigate the neutrino emissivity from quark Urca process in strong magnetic field. Then, we discuss the heat capacity of strange stars in strong magnetic field. Finally, we give the cooling curve in strong magnetic field. In order to make a comparison, we also give the corresponding cooling curve in the case of null magnetic field. It turns out that strange stars cool faster in strong magnetic field than that without magnetic field. 展开更多
关键词 strong magnetic field strange star QUARK
下载PDF
Gravitational Energy-Momentum and Conservation of Energy-Momentum in General Relativity 被引量:1
8
作者 吴兆颜 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第6期716-730,共15页
Based on a general variational principle, Einstein–Hilbert action and sound facts from geometry, it is shown that the long existing pseudotensor, non-localizability problem of gravitational energy-momentum is a resul... Based on a general variational principle, Einstein–Hilbert action and sound facts from geometry, it is shown that the long existing pseudotensor, non-localizability problem of gravitational energy-momentum is a result of mistaking different geometrical, physical ob jects as one and the same. It is also pointed out that in a curved spacetime, the sum vector of matter energy-momentum over a finite hyper-surface can not be defined. In curvilinear coordinate systems conservation of matter energy-momentum is not the continuity equations for its components. Conservation of matter energy-momentum is the vanishing of the covariant divergence of its density-flux tensor field. Introducing gravitational energy-momentum to save the law of conservation of energy-momentum is unnecessary and improper. After reasonably defining "change of a particle's energy-momentum", we show that gravitational field does not exchange energy-momentum with particles. And it does not exchange energy-momentum with matter fields either. Therefore, the gravitational field does not carry energy-momentum, it is not a force field and gravity is not a natural force. 展开更多
关键词 pseudotensor non-localizability gravitational energy-momentum energy-momentum conservation
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部