排序方式： 共有54条查询结果，搜索用时 15 毫秒
41.
影响新余蜜橘品质的气象因子及其变化趋势 总被引：1，自引：0，他引：1
利用新余市气候资料和蜜橘品质测定资料,运用相关分析方法,对影响新余蜜橘品质的气象因子及其变化趋势进行了分析。结果表明,积温、最高最低气温差、日照时数、降水量为影响新余蜜橘生长的主要因子。近几年温度（积温）和最高最低气温差有明显的年际增加的趋势,有利于新余蜜橘的发展;日照时数保持稳定并有所增加,降水量保持稳定并有所减少,预计未来几年也满足蜜橘生长需要。 相似文献
42.
The effects of a minimal length on the Kerr metric are studied within the pseudo-complex General Relativity (pcGR), which has a minimal length parameter and also depends on a -dependent metric, allowing for the accumulation of dark energy around a star. The relevant parameters are the rotational Kerr parameter , the mass of a black hole, and a parameter measuring the amount of dark energy accumulated. It is found that the metric is modified by a factor, depending on , resulting in a maximal acceleration. This factor shows several singularities. For small black holes, the corresponding effective potentials exhibit potential barriers, avoiding the increase of the black hole's mass. It is found that the effects of a minimal length are only of importance for very small mass black holes and vanish for macroscopic black holes. 相似文献
43.
地下水位与应变的相关性分析 总被引：3，自引：2，他引：3
根据弹性动态理论，变形介质中流体的动态，是由封闭含水层所受压力变化引起的。利用川－18井水位与仁和台钻孔应变资料，使用最大相关系数方法进行分析，结果表明在强震的孕育、发展的某一阶段，测点处的应力－应变场对于水位的变化起主导作用，这种相关性也可以作为异常判据。 相似文献
44.
本文简要介绍了时空度规、后牛顿近似、坐标选择、局部惯性系以及原时与坐标时等有关相对论参考系的基本概念，给出了常用时空坐标之间的变换关系。 相似文献
45.
Space experiments to test the Equivalence Principle (EP) are affected by a systematic radiometer effect having the same signature as the target signal. In [PhRvD 63 (2001) 101101(R)] we have investigated this effect for the three proposed experiments currently under study by space agencies: μSCOPE, STEP and GG, setting the requirements to be met—on temperature gradients at the level of the test masses—for each experiment to reach its goal. We have now re-examined the radiometer effect in the case of μSCOPE and carried out a quantitative comparative analysis, on this issue, with the proposed heliocentric LISA mission for the detection of gravity waves. We find that, even assuming that the μSCOPE spacecraft and payload be built to meet all the challenging requirements of LISA, temperature gradients along its test masses would still make the radiometer effect larger than the target signal of an EP violation because of flying in the low geocentric orbit required for EP testing. We find no way to separate with certainty the radiometer systematic disturbance from the signal. μSCOPE is designed to fly a second accelerometer whose test masses have the same composition, in order to separate out systematic effects which—not being composition dependent like the signal—must be detected by both accelerometers. We point out that this accelerometer is in fact insensitive to the radiometer effect, just as it is to an EP violation signal, and therefore even having it onboard will not allow this disturbance to be separated out. μSCOPE is under construction and it is scheduled to fly in 2004. If it will detect a signal to the expected level, it will be impossible to establish with certainty whether it is due to the well known classical radiometer effect or else to a violation of the equivalence principle—which would invalidate General Relativity. The option to increase the rotation speed of the spacecraft (now set at about 10−3 Hz) so as to average out the temperature gradients which generate the radiometer effect, is allowed in the GG design, not in that of STEP and μSCOPE. 相似文献
46.
R. A. Krikorian 《Astrophysics》2005,48(4):539-544
A well known theorem of relativistic hydrodynamics states that the streamlines of an isentropic perfect fluid are the future-pointing
timelike (FPT) curves extremizing the integral J = ∫
S1
S2
fds, where f is the so-called index function and s the proper time on the world line of the fluid particle. The integral is taken over all possible FPT curves with regular
representations xi = xi (s) joining the fixed end events E1, E2. The purpose of this note is to show that the streamlines of an adiabatic perfect fluid can likewise be regarded as extremizing
curves of the functional J provided the class of admissible curves consists of those FPT curves satisfying the side condition ui∂iS = 0, ui unit 4-velocity and S the specific proper entropy of the fluid, with the first end point fixed and the second being the end
point variable.
__________
Published in Astrofizika, Vol. 48, No. 4, pp. 641–647 (October–December, 2005). 相似文献
47.
渭河盆地地裂缝发育基本特征 总被引：3，自引：0，他引：3
渭河盆地由于其特殊的地质环境,是地裂缝发育较多的地区。本文在渭河盆地地裂缝详细调查的基础上,简要论述了地裂缝的分布概况,详细研究了渭河盆地地裂缝的发育基本特征,并初步探讨了地裂缝的成因。渭河盆地196条地裂缝大都密集分布在断层近侧,与断层走向有明显的一致性和相关性。地裂缝基本特征主要是形态特征和空间分布。地裂缝平面形态有直线、S型和锯齿状;剖面形态为上宽下窄,并逐渐消失;倾角较陡。地裂缝空间分布上有方向性、开启性和网络性。渭河盆地地裂缝主要是构造地裂缝,受构造断裂控制;地下水、地表水、采空和黄土湿陷性只是诱导因素。 相似文献
48.
Considering a GPS satellite and two terrestrial stations, two types of equations are derived relating the heights of the
two stations to the measured data (frequency ratio or clock rate differences) and the coordinates and velocity components
of all three participating objects. The potential possibilities of using such relations for the determination of heights (in
terms of geopotential numbers or orthometric heights) are discussed.
Received: 6 December 2000 / Accepted: 9 July 2001 相似文献
49.
广义相对论在时频计量中的应用 总被引：1，自引：0，他引：1
介绍了广义相对论在时频计量中的应用的重要性和当前研究现状，评述了该领域的几个主要问题：原（固有，本征）时与坐标时的关系；不同坐标时之间的转换；各种不同方式的时间比对及各种不同方式的频率比对，给出了有关研究的最新结果。最后，简要地讨论了该领域需要关注的几个问题。 相似文献
50.