排序方式: 共有134条查询结果,搜索用时 250 毫秒
21.
暗物质问题目前已受到物理学界的高度关注,因为这一课题的研究和进展,将直接影响到粒子物理、天体物理和宇宙学的发展方向。当前世界上已有一些大的实验组正在开展这方面的研究工作,并已取得了一定的结果;文章重点介绍两个重要的探测实验,即中意合作DAMA组(Dark Matter Group)100kg Nal(Tl)探测器阵列实验和美国的CDMS(Cold Dark Matter Search)实验组的低温探测器实验。详细介绍了DAMA实验的物理分析方法及其实验结果,并同CDMS实验结果进行了相应的比较。 相似文献
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We report a discovery of multiple outflows in IRAS 06056 2131. The high angular resolution image (~ 15“) of CO(1-0) emission reveals that the structure of outflow is very complicated. The outflow appears to be everywhere.Its configuration only show a bipolar outflow at observation of both low resolution and low signal-to-noise ratio,while two bipolar outflows can be detected when observed by both high resolution and high signal-to-noise ratio mapping. This result is significant in the understanding of the physical processes that occur at early phase of massive stars. 相似文献
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Angular distributions of the ^7Li(^6Li, ^6Li)^7Li elastic scattering and the ^7Li(^6Li, ^7Lig.s.)^6Li, ^7Li(^6Li, ^7Li0.48)^6Li transfer reactions at Ec.m. = 23.7 MeV are measured with the Q3D magnetic spectrograph. The optical potential of ^6Li + ^7Li is obtained by fitting the elastic scattering differential cross sections. Based on the distorted wave Born approximation (DWBA) analysis, spectroscopic factors of ^7Li =^6Li n are determined to be 0.73 ± 0.05 and 0.90 ± 0.09 for the ground and first exited states in ^7Li, respectively. Using the spectroscopic factors, the cross sections of the ^6 Li(n, γ0,1)^7 Li direct neutron capture reactions and the astrophysical ^6Li(n, γ)^7 Li reaction rates are derived. 相似文献
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We have developed approximate Riemann solvers for ideal MHD equations based on a relaxation approach in [4], [5]. These lead to entropy consistent solutions with good properties like guaranteed positive density. We describe the extension to higher order and multiple space dimensions. Finally we show our implementation of all this into the astrophysics code FLASH. 相似文献
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在太阳系外找到一颗适合人类居住的行星,是天体物理学家长期以来的梦想。适合人类居住,通常要求有液态水,这相应地要求:行星到母恒星的距离在一定的范围之内。按照最近Dumusque等在Nature周刊发表的研究报告,事情或许有了一定的眉目。研究者宣称,发现了一颗类地球太阳系外行星,它围绕半人马座α双星之一(B星)运转,半人马座α双星属于最接近太阳系的恒星,离我们仅4光年远。 相似文献
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Computational gas dynamical simulations using the WENO-LF method are applied to modeling the high Mach number astrophysical jet XZ Tauri, including the effects of radiative cooling. Mach 55 simulations of the pulsed proto-jet are presented and analyzed in terms of interacting nonlinear waves: terminal Mach disks, bow shocks, and Meshkov-Richtmyer instabilities of the leading jet contact boundary. 相似文献
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The wormhole equations are presented in the presence of tachyon field. Specializing at some values of ω(the ratio of pressure to energy density), we find a family of classical and quantum wormhole solutions. 相似文献
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Charge coupled devices (CCD) photometry and long-term optical variability of gamma-ray-loud BL Lacertae object Mkn 421 下载免费PDF全文
Evidence for the long-term optical curve variability and colour behaviour of the BL
Lac object Mkn 421 is presented. Our results show that the amplitude of the optical
variations of Mkn 421 is only about {\Delta} B=4.7 magnitude in the B-band for
its photometric history from 1899 to 2002. The results of optical photometric
monitoring of the Mkn 421 from April 2000 to Jan 2002 are provided. During our
observation, Mkn 421 shows significant rapid variations and exhibits short time
variability of 2.42 hours in the B band. A strong correlation between the B-V
colour index and the magnitude in the B band is found. Our charge coupled device
(CCD) photometry of Mkn 421 shows that the measured results are in good agreement
with the predicted optical variability period of about 23 years. 相似文献
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XIE Bai-Song 《理论物理通讯》2006,46(3):561-562
Two new solutions for non-constant-α force-free magnetic field are found analytically. Implications of the results to astrophysical solar plasmas as well tokamak plasmas are discussed. 相似文献