金刚石钻头底唇胎体拉槽分析与研究     

杨建新 《河南国土资源》1996,(4)

本文根据河南省小秦岭金矿田在钻探施工中，小口径金刚石钻头底唇胎体拉槽、推光头的现象和特征，全面地观察和剖析了发展规律及导致拉槽的过程，提出了独特的见解和认识，研究出了使用钻头的正确方法，拟供同类矿区借鉴  相似文献   

Sequences in the Hardness Ratio-Peak Energy Plane of Gamma-Ray Bursts     

Xiao-Hong Cui  En-Wei Liang  Rui-Jing Lu National Astronomical Observatories/Yunnan Observatory  Chinese Academy of Sciences  Kunming  ciwei@.com Department of Physics  Guangxi University  Nanning Department of Astronomy  Nanjing University  Nanjing Graduate School of the Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2005,5(2):151-158

The narrowness of the distribution of the peak energy of the vFv spectrum of gamma-ray bursts (GRBs) and the unification of GRB populations are great puzzles yet to be solved. We investigate the two puzzles based on the global spectral behaviors of different GRB populations, the long GRBs, the short GRBs, and the X-ray flashes (XRFs), in the HR - Ep plane (HR the spectral hardness ratio) with BATSE and HETE-2 observations. It is found that the long GRBs and the XRFs observed by HETE-2 seem to follow the same sequence in the HR-Ep plane, with the XRFs at the low end of this sequence. We fit the sequence by a universal Band function, and find that this sequence is mainly defined by the low energy index α, and is insensitive to the high energy index,β. With fixed β=-5, a best fit is given by α=-1.00 with X^2min/dof=2.2. The long and short GRBs observed by BATSE follow significantly different sequences in the HR-Ep plane, with most of the short GRBs having a larger hardness ratio than the long GRBs at a given Ep. For the long GRBs a best-fit yields α=-0.30 and β=-2.05. For the short GRBs, a best fit gives α=-0.60 with x^2min=1.1 (withβfixed at-2.0 because it is numerically unstable). The α value for the short GRBs is significantly greater than that for the long GRBs. These results indicate that the global spectral behaviors of the long GRB sample and the XRF sample are similar, while that of the short GRBs is different. The short GRBs seem to be a unique subclass of GRBs, and they are not the higher energy extension of the long GRBs.  相似文献   

矿泉水的现场分析     

高国华  周金生 《地质实验室》1991,7(1):58-60

  相似文献   

太阳磁场观测研究   总被引：5，自引：0，他引：5  

刘煜  张洪起  包曙东 《天文学进展》2001,19(1):34-44

简要回顾了近几年国际上太阳磁场研究的一些重要进展，包括耀斑与磁切和电流的关系，电流螺度和磁螺度，磁场拓扑性，三维磁场外推，色球磁场研究，日冕磁场研究，内网络磁元，磁流和振荡，极区磁场观测以及色球磁元观测等方面内容，同时也介绍了怀柔太阳观测站最近所取得的主要成果，自20世纪90年代以来，YOHKOH高分辨率的太阳X射线数据，SOHO的多波段大尺度观测，TRACE的高分辨太阳过渡区资料，为研究太阳磁场从内部到距离几十太阳半径处的大范围演化提供了依据，高效的空间资料结合长期的地面资料，将是正派推动太阳磁场研究的重要手段和必然趋势。  相似文献   

CSAO和VS NIIFITRI等高仪国际合作观测精度的初步分析     

徐家岩  Zalu.  VT 《时间频率学报》1997,20(6):66-70

初步分析了ＰＨＡ Ｉ在伊尔库茨克近１４个月中观测的８２２组星的精度。ＰＨＡ Ｉ创造了它历史上最多的观测星组数和最高的观测精度。１９９６年在俄罗斯地球自转参数系统中获取１５％的权重，约为该系统平均仪器权重的３倍多。  相似文献   

差分观测与伪距观测的定位精度     

孙宏伟  李玉莉 《时间频率学报》1993,(2)

严格论证了在对空间或地面目标的定位中,利用伪距测量观测模型的几何因子大于用台站间一次差分观测模型的几何因子.此外,台站间完全差分测量观测的定位精度优于不完全测量情形的定位精度.这些结果给人们在实际工作中采取何种定位方式提供了可靠的理论依据.  相似文献   

比值分析及其在伴生元素评价中的应用          下载免费PDF全文

赖应篯  黄慧玲 《地质与勘探》1993,(5)

比值分析是利用伴生元素含量(x)与主元素含量(c)在矿石中的比值(α=x_0/c_0),在矿物中的比值(b=x_i/c_i)以及两者的比值(称比值系数k=b/α),对伴生元素赋存规律进行分析研究的方法。b值和矿石中仅有一种矿物含某种伴生元素的a值,可确切了解伴生元素自身变化、富集规律及其在载体矿物中分布的均匀程度;矿石中与各矿物相关联的k值具有如下关系:k_1+k_2+…=1,据此可确定伴生元素在各有关矿物中的分配情况和判断赋存有该种伴生元素的矿物是否全部查明。  相似文献   

在太阳连续谱中的五分钟振荡     

张衡 《云南天文台台刊》1992,(1):20-35

  相似文献   

卫星电视授时系统及精度估计   总被引：1，自引：0，他引：1  

宋金安 《时间频率学报》1994,(Z1)

我国已建成短波、长波授时台，进行毫秒级、微秒级的时间服务．随着现代科技和经济的发展，上述方法已不能满足国家及国际交流的需要．本文提出卫星电视授时系统，同步卫星定位精度小于１１０ｍ，卫星授时精度为亚微秒。两原子钟利用卫星进行时刻同步，其精度与两原子钟的距离有关，相距３千多公里的两钟同步精度小于３５ｎｓ，相距数百公里的两原子钟同步精度小于２０ｎｓ  相似文献   

Magnetic Field Strengths and Structures from Radio Observations of Solar Active Regions     

Chang－XiZhang  G.B.Gelfreikh 《中国天文和天体物理学报》2002,2(3):266-276

Radio observations of some active regions (ARs) obtained with the Nobeyama radioheliograph at λ=1.76cm are used for estimating the magnetic field strength in the upper chromosphere, based on thermal bremsstrahlung. The results are compared with the magnetic field strength in the photosphere from observations with the Solar Magnetic Field Telescope (SMFT) at Huairou Solar Observing Station of Beijing Astronomical Observatory. The difference in the magnetic field strength between the two layers seems reasonable. The solar radio maps of active regions obtained with the Nobeyama radioheliograph, both in total intensity (I-map) and in circular polarizations (V-map), are compared with the optical magnetograms obtained with the SMFT. The comparison between the radio map in circular polarization and the longitudinal photospheric magnetogram of a plage region suggest that the radio map in circular polarization is a kind of magnetogram of the upper chromosphere. The comparison of the radio map in total intensity with the photospheric vector magnetogram of an AR shows that the radio map in total intensity gives indications of magnetic loops in the corona, thus we have a method of defining the coronal magnetic structure from the radio I-maps at λ=1.76 cm. Analysing the I-maps, we identified three components: (a) a compact bright source; (b) a narrow elongated structure connecting two main magnetic islands of opposite polarities (observed in both the optical and radio magnetograms); (c) a wide, diffuse, weak component that corresponds to a wide structure in the solar active region which shows in most cases an S or a reversed S contour, which is probably due to the differential rotation of the Sun. The last two components suggest coronal loops on different spatial scales above the neutral line of the longitudinal photospheric magnetic field.  相似文献