Polarization of X-ray emission from the Sgr B2 cloud

The Sgr B2 giant molecular cloud is claimed to be an 'X-ray reflection nebula'– the reprocessing site of a powerful flare of the Sgr A* source, which occurred a few hundred years ago. The shape of the X-ray spectrum and the strength of the iron fluorescent line support this hypothesis. We argue that the cleanest test of the origin of X-rays from Sgr B2 would be a detection of polarized emission from this source.     

无法方程组平差

本文旨在提供一种适合计算机编制程序的平差算法,其中心思想是通过对平差数学模型中A系数阵进行初等变换,直接求得用虚拟独立参数表示的平差数学模型,然后根据虚拟独立参数与原平差模型参数的数学联系,求得原平差模型参数及有关精度。     

Temperature evolution of the envelope of SN 1987A

We present a theoretical derivation of the H_α line luminosity of the expanding envelope of SN 1987A from the theory of hydrogen recombination lines. A remarkable deviation of our calculated H_α light curve from the observed light curve was found when a constant temperature was assumed. From the deviation we easily derive the temperature evolution. The temperature actually rises after day 500 and this may be explained as follows: as the shell expands, the electron and ion densities rapidly fall, greatly reducing the recombination cooling rate, while heating continues.     

辽南庄河—凤城断裂构造变形及其成矿作用

庄河－凤城断裂走向北东，形成于早中生代，属辽南区域性切壳断裂构造，规模大、变形强、活动期次多，对成岩成矿有重要控制作用。     

UBV photometry of the Ap variable UZ Psc = HD 10783

NewUBV photometry, obtained between late 1965 and early 1969, is presented and combined with existing published photometry to derive an improved ephemeris for times of maximum brightness: 2439758.00+4 _d ^. .1328n. On leave from Dyer Observatory, Vanderbilt University, Nashville, Tennessee, U.S.A.     

’92、’96国家高精度GPS A级网整体平差结果分析与我国块体运动模型研究

对’９２、’９６国家高精度ＧＰＳＡ级网进行了不同方案的整体平差,研究了利用全国范围的高精度ＧＰＳ网进行我国地壳形变监测的数据处理和分析方法。利用具有可比性９２Ⅲ和９６Ⅱ平差方案建立了在ＩＴＲＦ９３框架下的我国块体运动模型,并与ＮＮＲ－ＮＵＶＥＬ１Ａ模型进行了比较;同时研究了我国的板内块体运动模型,这一结果与地质结果较为一致。     

磁暴期内夜间h’F的突增现象

用3个经度链上电离层垂测站资料分析磁暴时夜间h＇F的同时突增现象提出了电动耦合在夜间出现东向电场从而使F层抬升的物理机制同时也解释了突增现象在午夜后更多,且增幅更强的事实．     

The influence of heat conduction on evaporation from sunken pans in hot, dry environment

Lateral heat conduction across a large circular sunken pan located in a hot, dry environment is evaluated using a numerical procedure. Heat flow across the sunken pan–adjacent soil boundary is calculated using a two-dimensional soil plane. Calculations show that a large temperature differential across the pan–substrate boundary develops during the entire diurnal cycle during January and July, leading to consistently positive heat flow from the soil towards the sunken pan. Heat conduction across the pan–substrate boundary represents 10 and 34% of net radiation over the sunken pan during July and January, respectively. This additional heat source, which is not available for shallow lakes, increases annual evaporation from the sunken pan by about 5–8% in July and January, respectively. In hot arid environments, a sunken pan will overestimate evaporation from a nearby shallow lake/dam due to a larger surface roughness and consistently positive conduction heat flow across the pan–substrate boundary.