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141.
SABen-Hao CAIXu TAIAn ZHOUDai-Mei 《理论物理通讯》2004,42(3):403-406
We present the simulation results of the net charge fluctuation in Au Au collisions at √Snn=130 GeV from a dynamic model, JPCIAE, and its revisions. The simulations are done for the quark-gluon matter, the directly produced pions, the pion matter, and the hadron matter. The simulated net charge fluctuation of the quark-gluon matter is close to the thermal model prediction for the quark-gluon gas. However, the discrepancy exists comparing the simulated net charge fluctuation for directly produced pions and the pion matter with the thermal model prediction for pion gas and the resonance pion gas, respectively. The net charge fluctuation of hadron matter from default JPCIAE simulations is nearly 3.5 times larger than quark-gluon matter. A discussion is given for the net charge fluctuation as an evidence of QGP phase transition. 相似文献
142.
The vacuum system of today's tokamak devices is designed to meet the operational requirements of the experiments. The operation can be divided into five modes, (1) pumping down and leak detecting of the vacuum vessel, (2) baking, (3) plasma-facing component (PFC) conditioning, (4)evacuating and controlling of the particles at plasma edge, (5) plasma discharge experiments. 相似文献
143.
GAO Xiaoyan CAI Xiao CAO Zeng CUI Chenghe 《核工业西南物理研究院年报(英文版)》2004,(1):54-56
HL-2A is the first divertor tokamak in China. The vacuum system is one of the important parts of the HL-2A tokamak, which has to be work well during the physics campaign in 2004. As the tokamak machine is separated from the operation staff during discharges, to guarantee the safe and reliable operation of the vacuum system, it is necessary to watch the vacuum system outside the machine hall with an automatic monitoring system. The paper describes the design and manufacture of the monitoring system. 相似文献
144.
Balance equations are established for steady-state nonlinear electronic transport in the presence of an electric field both for a single quasi 1D-heterostructure and for a multi-quantum-wire superlattice. The carrier-impurity scatterings and carrierphonon scatterings have been taken into account. The general equations for determining the resistivities are obtained and the Ohmic mobility formula are given. The density-density correlation functions for the wire structures are also studied in some detail. 相似文献
145.
The correlation between neutron-to-proton yield ratio (Rnp) and neutron skin thickness (δnp) in neutron-rich projectile induced reactions is investigated within the framework of the Isospin-Dependent Quantum Molecular Dynamics (IQMD) model. The density distribution of the Droplet model is embedded in the initialization of the neutron and proton densities in the present IQMD model. By adjusting the diffuseness parameter of neutron density in the Droplet model for the projectile, the relationship between the neutron skin thickness and the corresponding Rnp is obtained. The results show strong linear correlation between Rnp and δnp for neutron-rich Ca and Ni isotopes. It is suggested that Rnp may be used as an experimental observable to extract δnp for neutron-rich nuclei, which is very interesting in the study of the nuclear structure of exotic nuclei, the equation of state (EOS) of asymmetric nuclear matter and neutron-rich matter in astrophysics, etc. 相似文献
146.
The spatial structures of magnetic Co nanowire array embedded in anodic aluminium membranes were investigated by grazing incidence small angle X-ray scattering (GISAXS) and conventional small angle X-ray scattering (SAXS) techniques. Compared with SEM observation, the GISAXS and SAXS measurements can get more overall structural information in a large-area scale. In this study, the two-dimensional GISAXS pattern was well reconstructed by using the IsGISAXS program. The results demonstrate that the hexagonal lattice formed by the Co nanowires is distorted (a ≈ 105 nm, b ≈ 95 nm). These Co nanowires are isolated into many structure domains with different orientations with a size of about 2 μm. The SAXS results have also confirmed that the nanopore structures in the AAM can be retained after depositing Co nanowires although the Co nanowires can not completely but only just fill up the nanopores. These results are helpful for understanding the global structure of the Co nanowire array. 相似文献
147.
莫晓虎 张建勇 张清江 Achasov Mikhail 蔡啸 傅成栋 Harris Fred 刘倩 Muchnoi Nikolay 秦庆 屈化民 王贻芳 徐金强 张天保 《中国物理 C》2011,35(7):642-655
Understanding the radiation background at the north crossing point (NCP) in the tunnel of BEPCII is crucial for the performance safety of the High Purity Germanium (HPGe) detector, and in turn of great significance for long-term stable running of the energy measurement system. Therefore, as the first step, a NaI(Tl) detector is constructed to continuously measure the radiation level of photons as background for future experiments. Furthermore, gamma and neutron dosimeters are utilized to explore the radiation distribution in the vicinity of the NCP where the HPGe detector will be located. Synthesizing all obtained information, the shielding for neutron irradiation is studied based on model-dependent theoretical analysis. 相似文献
148.
背景主色的确定是迷彩伪装的关键问题,针对现有提取方法的不足,提出一种基于八叉树颜色量化和链表统计的背景主色提取算法.首先对图像进行八叉树颜色量化,然后统计量化后图像的颜色,并用链表存储,最后依据人眼视觉特性和相应准则确定背景主色.该算法可以对多 幅图像进行处理且运算时间较短.实验表明这种方法能够满足迷彩伪装颜色确定的要... 相似文献
149.
150.