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1.
叙述了与Astrod工程有关的相对论天体力学基础内容。包括相对论天体力学、广义相对论基本原理、PPN方法体系、PPN多体问题、PPN二体问题。高阶PN二体问题等  相似文献   
2.
Microwave Type III bursts with positive frequency drifting rate were found by Stahli and Benz (1987) for first time. Type III events are especially interesting because they are well-known to be signatures of electron beams in coronal plasma, and they are effective means for diagnosting of source plasma. A microwave burst consisting of some microwave type III burst groups was registered at Beijing Astronomical Observatory with the 2545–2645–2840 MHz synchronous observing system. The distributions of frequency drifting rate, half power duration, and intensity for each impulse in the groups have been statistically analysed. From this analysis, some important parameters for the dynamic process in the flare are deduced and discussed.  相似文献   
3.
An improved Solar Radio Spectrometer working at 1.10-2.06 GHz with much improved spectral and temporal resolution, has been accomplished by the National Astronomical Observatories and Hebei Semiconductor Research Institute, based on an old spectrometer at 1-2 GHz. The new spectrometer has a spectral resolution of 4 MHz and a temporal resolution of 5ms, with an instantaneous detectable range from 0.02 to 10 times of the quiet Sun flux. It can measure both left and right circular polarization with an accuracy of 10% in degree of polarization. Some results of preliminary observations that could not be recorded by the old spectrometer at 1-2 GHz are presented.  相似文献   
4.
Advanced material constitutive models are used to describe complex soil behaviour. These models are often used in the solution of boundary value problems under general loading conditions. Users and developers of constitutive models need to methodically investigate the represented soil response under a wide range of loading conditions. This paper presents a systematic procedure for probing constitutive models. A general incremental strain probe, 6D hyperspherical strain probe (HSP), is introduced to examine rate‐independent model response under all possible strain loading conditions. Two special cases of HSP, the true triaxial strain probe (TTSP) and the plane‐strain strain probe (PSSP), are used to generate 3‐D objects that represent model stress response to probing. The TTSP, PSSP and general HSP procedures are demonstrated using elasto‐plastic models. The objects resulting from the probing procedure readily highlight important model characteristics including anisotropy, yielding, hardening, softening and failure. The PSSP procedure is applied to a Neural Network (NN) based constitutive model. It shows that this probing is especially useful in understanding NN constitutive models, which do not contain explicit functions for yield surface, hardening, or anisotropy. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
5.
We propose a model of two acceleration regions, which can explain, on the basis of microwave maser caused by a “hollow-beam” distribution of electrons, the presence of millisecond spikes in the event of 1981 May 16 and their absence in the event of 1981 October 12, and the enhanced continuous emission in the latter. We have also uncovered relations among the features, e.g. the Type IIIG, Type IVDCIM and hard x-ray bursts, that accompany the microwave millisecond spikes during the impulsive phase of a large flare.  相似文献   
6.
提出了保持质量体系有效运行的前提和基础 ,关键和保证措施 ,并指出了组织企业保持质量体系持续有效的方法和途径。  相似文献   
7.
The IRAS and 2MASS associations for 193 T Tauri stars are identified in this paper. From the color–color diagrams and spectral index, it is found that the IR excesses for most samples are due to thermal emission from the circumstellar material, as suggested previously. It is also found that the IR excesses at IRAS region for few T Tauri stars and the near-IR excesses for some T Tauri stars are likely attributed to free-free emission or free-bound emission from the circumstellar ionized gas. Moreover, It is found in deredened J–H versus H–K color–color diagram that there is a slight separation in different spectral groups. The T Tauri stars locus equation in J–H versus H–K color–color diagram for our sample is also presented.  相似文献   
8.
土壤中氟的形态分析   总被引:11,自引:3,他引:8  
以宁夏盐池地区高氟土壤为例,采用连续提取法对土壤样品中各形态氟进行提取,离子色谱法测定各形态氟的含量。根据研究目的及土壤特点将氟的形态划分为水溶态、离子交换态、可还原态、可氧化态及残渣态5种形态;对各种形态连续提取过程中使用的提取液进行了选择。采用建立的方法获得提取土壤中F-的检出限为0.76μg/g;方法精密度(RSD,n=7)各形态氟为水溶态氟11.3%,离子交换态氟13.5%,可还原态氟10.7%,可氧化态氟8.9%。  相似文献   
9.
10.
天津地面沉降区土水比论述   总被引:1,自引:0,他引:1  
天津市地面沉降分布广,沉降速率大。本文针对当前地面沉降研究和防治过程中所遇到的勘查资料严重缺乏、禁采难以全面实现等难题,提出了土水比指标量。通过概念分析和对多年数据的分析,认为土水比可以检验地下水开采量数据的统计精度,指示地下水资源补给及土层释水条件,并表明沉降的严重程度,反映地下水资源的保障程度。建议在沉降防治工作中,以土水比作为指标,通过相关分析模型来制定压采量。  相似文献   
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