排序方式： 共有166条查询结果，搜索用时 312 毫秒
131.
Ernst-Jan Buis Marco Beijersbergen Stefan Kraft Alan Owens Francesco Quarati Sytze Brandenburg Reint Ostendorf 《Experimental Astronomy》2005,20(1-3):333-339
Recent developments of cerium-doped lanthanum-halide scintillators like LaBr3:Ce show a remarkable performance in gamma-ray spectroscopy. When high energy resolution in combination with stopping power is required they provide excellent gamma-ray detector candidates for the use in space missions. Moreover, irradiation tests have shown that such detectors are radiation tolerant. In this paper we discuss a possible application of LaBr in nuclear astrophysics missions. We show results on recent proton irradiation tests at KVI in Groningen (NL) and discuss the damage and activation effects after irradiation. A possible implementation for a focal plane detector in a gamma-ray telescope and the expected performance is presented. 相似文献
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正在进行的实验室天体物理测量解决了X射线天文学的一些问题，这些实验产生了大量可靠的原子数据，它们既可用于电荷分布中电离与复合截面的计算，又可用于对X射线谱线形成的线表、激发截面及双电子复合系数的理解。另有一部分实验注重于解决天体观测的难题，以及验证现有的和寻找新的X射线谱线诊断。讨论了上述实验产生的数据类型，并展示了实验室测量如何为卫星（ASCA、EUVE、Chandra、XMM和ASTRO-E2）观测提供实验依据． 相似文献
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The existence of a critical height for quiescent prominences and its relationship to parameters of the magnetic field of photospheric sources are discussed. In the inverse-polarity model, stable equilibrium of a filament with a current is possible only in the region where the external field decreases with height no faster than ～1/h. Calculations of the potential magnetic field above the polarity-inversion line are compared with the observed prominence height. The prominence height is shown to actually depend on the vertical field gradient and does not exceed the level at which the exponent of field decrease is equal to unity. 相似文献
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简要介绍了计算机模拟的基本原理和方法 ,以及数值模拟计算在天体物理学中的主要应用结果和前景 相似文献
137.
《Chinese Astronomy and Astrophysics》2021,45(3):265-280
In recent years, with the development of megajoule-class laser, to create the physical conditions similar to those of extreme celestial environments in the laboratory has become possible. This makes scientists able to study some important astrophysical processes and physical phenomena in the laboratory. This paper briefly introduces several advances in the high energy density laboratory astrophysics driven by the National Ignition Facility (NIF), including the Rayleigh-Taylor instability in supernova remnants, the collisionless shock wave, the laser inertially-confined fusion detection of the thermonuclear reaction under the stellar core condition, the study of planetary interior state, the study of star formation, etc., which will provide a reference for the scientific experiments in the field of laboratory astrophysics performed by using the Shenguang IV laser facility under construction in China. Finally, the possible scientific issues relevant to the direction of laboratory astrophysics by using the Shenguang IV laser facility in the future are briefly discussed. 相似文献
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The history of cosmic ray studies can be traced back to the 1910s when Hess and other scientists first discovered them. Cosmic rays are very important laboratories of particle physics, and have led to many important discoveries of fundamental particles, such as the positrons, muons, pions, and a series of strange particles. Cosmic rays are nowadays the key probes of the extremely high-energy physics and dark matter particles. A brief review about the history and recent progresses of direct observations of cosmic rays is presented. In recent years, the new space-borne experiments such as PAMELA and AMS-02, as well as a few of balloon-borne experiments, have measured the energy spectra of cosmic rays very precisely, and revealed several new features/anomalies. Remarkable excesses of positron fraction in the total electron plus positron fluxes have been observed, which may be caused by the annihilation/decay of dark matter particles or by astrophysical pulsars. The cosmic ray antiprotons, which are expected to have the same secondary origin as that of positrons, do not show significant excesses compared with the background prediction. This result also constrains the modeling of the positron excesses. In addition, the spectral hardening above several hundred GeV of cosmic ray nuclei has been revealed. These results have important and interesting implications on our understandings of the origin, acceleration, and propagation of cosmic rays. In particular, China has launched the Dark Matter Particle Explorer (DAMPE) to indirectly search for the dark matter and explore the high-energy universe in the TeV window. Most recently, the DAMPE collaborators reported the new measurements of the cosmic ray electron plus positron fluxes up to about 5 TeV with a very high precision. The DAMPE data revealed clearly a deflection around 0.9 TeV in the electron energy spectrum. Possible fine structures of the electron plus positron spectra can be critically addressed with the accumulation of data in the coming years. 相似文献
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分别从物理学和天文学角度引申出天体物理学科,特别关注万有引力在其中扮演的关键角色.无论在综合性大学亦或理工科院校,天文教育均有益于提高学生的科学和人文素养,而天体物理则是天文学的主要内涵.介绍了作者讲授"天体物理"课程的相关信息以及个人认识.最后,以大气簇射μ子产生、啾质量、宇宙加速膨胀等教学案例结束,侧面诠释了作者的"天体物理"教育理念. 相似文献
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引力波和引力波望远镜的发展 总被引：1，自引：1，他引：1
简要回顾了广义相对论中相关的引力波理论，讨论了对引力波进行探测的重要意义和几种可能的途径；系统介绍了近50年来国际上对引力波进行探测的主要活动，以及当前几个具有代表性的引力波望远镜工程的进展。 相似文献