Self-similar shocks in polytropic gas flows around star-forming regions     

Yu-Qing Lou  Yang Gao 《Monthly notices of the Royal Astronomical Society》2006,373(4):1610-1618

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Semi-empirical models of the white-light flare on October 24, 1991     

C. Fang  J. C. Hénoux  Hu Ju  Xue Yin-Zhang  Gao Xiu-fa  Fu Qi-Jun 《Solar physics》1995,157(1-2):271-283

On October 24, 1991, a white-light flare was observed both from space and from the ground. A multi-waveband spectral analysis shows that the peak time of the continuum emission coincides well with that of a radio burst at 2840 MHz and with the hard X-ray emission. Three semi-empirical models, corresponding to the pre-flare condition and to the peak time of continuum emission both with and without non-thermal excitation and ionization of hydrogen by an electron beam, have been obtained. The results indicate that there is fast heating both in the chromosphere and the photosphere. Some evidence is given that this WLF is very likely a result of bombardment by an electron beam. By taking into account non-thermal effects, the chromospheric temperature of the semi-empirical model is significantly reduced.  相似文献   

Voids in a ΛCDM universe     

Jörg M. Colberg  Ravi K. Sheth  Antonaldo Diaferio  Liang Gao  Naoki Yoshida 《Monthly notices of the Royal Astronomical Society》2005,360(1):216-226

We study the formation and evolution of voids in the dark matter distribution using various simulations of the popular Λ cold dark matter cosmogony. We identify voids by requiring them to be regions of space with a mean overdensity of −0.8 or less – roughly the equivalent of using a spherical overdensity group finder for haloes. Each of the simulations contains thousands of voids. The distribution of void sizes in the different simulations shows good agreement when differences in particle and grid resolution are accounted for. Voids very clearly correspond to minima in the smoothed initial density field. Apart from a very weak dependence on the mass resolution, the rescaled mass profiles of voids in the different simulations agree remarkably well. We find a universal void mass profile of the form  ρ(< r )/ρ( r _eff) ∝ exp[( r / r _eff)^α]  , where r _eff is the effective radius of a void and  α∼ 2  . The mass function of haloes in voids is steeper than that of haloes that populate denser regions. In addition, the abundances of void haloes seem to evolve somewhat more strongly between redshifts ∼1 and 0 than the global abundances of haloes.  相似文献   

具有硅酸盐尘埃特征碳星的新的候选者   总被引：1，自引：1，他引：0  

陈培生  高衡 《天文学报》1994,35(4):443-447

本文根据红外天文卫星的宽波段测光及低分辨率光谱资料，给出了两颗新的可能具有硅酸尘埃特征的碳星及４颗可能的候选者。  相似文献   

板块构造图的制图理论与方法探讨     

高延林 《青海国土经略》2001,(2)

通过编制区域性1:300万“青藏高原板块构造图”和1:50万“柴达木北缘板块构造地质图”的体会,并结合国内学者对这两份图件的审查意见及建议,重点讨论有关区域性板块构造图编制的理论与方法,供区域地质工作者参考。  相似文献   

ESR DATING OF FLUVIAL SEDIMENTS USING GE CENTER IN QUARTZ   总被引：3，自引：0，他引：3  

业渝光  和杰  刁少波  高钧成 《中国地理科学(英文版)》1993,3(3):284-289

Using the Ge centers of quartz sediments, the buried ages of fluvial sediments were determined by ESR technique. The ESR ages obtained from Ge centers are consistent with the TL ages, correspond with their horizons, accord with the geological background, and every ESR age is available. In this paper, determination of total dose of natural radiation (TD) and the reliability of ESR age using Ge center are also discussed.  相似文献   

东风盐场卤水中可溶性糖的研究──Ⅰ、盐田卤水中可溶性糖的季节变化及其与海盐产量和质量之间的关系     

宫相忠  董树刚  吴以平  魏建功  高尚德  李永祺 《海洋湖沼通报》1997,(2)

对东风盐场9个站位卤水中由藻类植物产生的可溶性糖浓度的变化规律及其与海盐产量和质量之间的关系进行了研究。结果表明，各站位可溶性糖含量的变化范围为0．7－124．3mg／L，以6月份最高，2月份最低；卤水中可溶性糖在111mg／L－215mg／L范围内，结晶盐的产量随卤水中可溶性糖含量的增加而提高，但同时降低了NaCl的含量，并增加了可溶性杂质及水分的含量，从而降低了盐质。初始可溶性糖浓度为111mg／L、137mg／L、160mg／L、193mg／L和215mg／L的25．4°Be’的卤水，在日照下实验12天，其对应结晶盐的NaCl含量分别为91．66％、90．63％、90．48％、90．23％和88．46％，可溶性杂质的含量分别为3．05％、3．32％、3．33％和4．54％。  相似文献   

香山绝对点周围的局部地壳变形及其对重力测量结果的影响   总被引：1，自引：0，他引：1  

刘少明  高荣胜  贾民育 《大地测量与地球动力学》2002,22(2):97-100

为了监视北京地区的地壳稳定性，北京测绘院对10多个基岩点和北京市区进行了多次沉降观测，结果表明香山点近10多年来高程变化只有几毫米，其重力效应可略而不计，但测点东北和东南方有两个较大的下沉区。用线积分法计算了两个局部沉降的重力效应，在沉降区中心其影响可达0.38μms^-2，但对香山点的重力效应非常小，完全可以忽略。因此得出如下结论：香山点观测到的重力变化不是地壳变形引起的。  相似文献   

地球信息科学是跨学科的新领域     

孙枢 《地球信息科学学报》1997,(4):20-20

今天我非常高兴能够在香港回归以后不到2月的时间,前来参加这么一次重要的会议。首先请允许我代表中国国家自然科学基金委员会,向中国科学院和香港中文大学联合建立的地球信息科学联合实验室表示衷心的、热烈的祝贺! 我本人是一个地质学家,所以我愿意把地球信息科学看成是我们地学的一个前沿的、非常有发展前景的领域。但是我想也许更准确一点看,地球信息科学是一个跨学科的新科学领域。  相似文献   

嵩山地区新构造运动研究     

王清利  陈蜀园 《河南国土资源》2001,(1)

根据几年来对嵩山地区的考察和研究 ,通过对夷平面、河流阶地、串珠状洪积扇等诸多地貌现象的分析 ,论述了嵩山地区新构造运动以间歇性抬升运动和掀斜运动为主的特征。  相似文献