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Performance researches on three-phase transformer high voltage type electron accelerator
No full text在当前国际上，强流大功率电子加速器的研究是应用于辐射行业辐射源的一个主要研究方向。内置加速管三相高压变压器型电子加速器与外置加速管强流大功率电子加速器相比，具有结构紧凑、造价低、结构简单等特点。本文对内置加速管三相变压器型电子加速器在研制过程中出现的高压击穿频繁、高压硅堆的损坏率高、能量脉动高、引出窗束流损失大等问题进行了研究，提出并实施了改进措施，得到了较好的调试结果。并对存在的问题进一步提出了改进方案。首先介绍了内置加速管三相变压器型电子加速器的原理、结构及组成。在此基础上，针对在加速器调试过程中出现的经常性高压击穿等严重制约加速器正常运行的问题，通过对三相高压变压器型的高压发生器在变压器特性分析、气体绝缘和电场分布计算、高压电极形状优化、过电压分布的计算、正常工作时的仿真，提出了改进方案。经过改进后，从调试结果来看，所设计的高压发生器能够正常稳定的工作。研究了作为高压发生器易损坏的关键部件之一的高压整流硅堆的性能。根据硅堆内部的结构和在高压发生器中所处的位置，合理的建立了等效电路，并对电路中各结构电容在硅堆耐高压方面的作用进行了详细的理论计算和分析。对硅堆内部管芯的排列及在加速器中的摆放位置提出了改进方案，经过改进，提高了硅堆的耐压值，也保证了高压发生器的正常稳定运行。对于加速器引出窗束流损失大和能量脉动高的问题，用PBGUN程序计算了优化后的阴极鼻锥聚束极结构在强流状态下的束流轨迹和加速管出口处的束斑；对能量脉动测量做了分析，并得到较真实的脉动值。论文最后对内置加速管三相变压器型电子加速器在整体调试中存在电子束受到变压器杂散磁场影响的问题做了介绍，提出了分离式的改进结构在当前国际上，强流大功率电子加速器的研究是应用于辐射行业辐射源的一个主要研究方向。内置加速管三相高压变压器型电子加速器与外置加速管强流大功率电子加速器相比，具有结构紧凑、造价低、结构简单等特点。本文对内置加速管三相变压器型电子加速器在研制过程中出现的高压击穿频繁、高压硅堆的损坏率高、能量脉动高、引出窗束流损失大等问题进行了研究，提出并实施了改进措施，得到了较好的调试结果。并对存在的问题进一步提出了改进方案。首先介绍了内置加速管三相变压器型电子加速器的原理、结构及组成。在此基础上，针对在加速器调试过程中出现的经常性高压击穿等严重制约加速器正常运行的问题，通过对三相高压变压器型的高压发生器在变压器特性分析、气体绝缘和电场分布计算、高压电极形状优化、过电压分布的计算、正常工作时的仿真，提出了改进方案。经过改进后，从调试结果来看，所设计的高压发生器能够正常稳定的工作。研究了作为高压发生器易损坏的关键部件之一的高压整流硅堆的性能。根据硅堆内部的结构和在高压发生器中所处的位置，合理的建立了等效电路，并对电路中各结构电容在硅堆耐高压方面的作用进行了详细的理论计算和分析。对硅堆内部管芯的排列及在加速器中的摆放位置提出了改进方案，经过改进，提高了硅堆的耐压值，也保证了高压发生器的正常稳定运行。对于加速器引出窗束流损失大和能量脉动高的问题，用PBGUN程序计算了优化后的阴极鼻锥聚束极结构在强流状态下的束流轨迹和加速管出口处的束斑；对能量脉动测量做了分析，并得到较真实的脉动值。论文最后对内置加速管三相变压器型电子加速器在整体调试中存在电子束受到变压器杂散磁场影响的问题做了介绍，提出了分离式的改进结
基于微通道板的多击响应位置灵敏探测器
No full text与传统的四角延迟线阳极相比,三层延迟线阳极,即六角延迟线阳极具有很好的多击信号读出本领。它与微通道板结合,能够探测很短时间间隔内到达的多个粒子的时间和位置信息。文章介绍了基于微通道板的六角阳极探测器的结构及多击响应原理,报道了利用Puα源对该探测器及中心带孔的六角阳极探测器的测试结果,探测器位置分辨好于0.2毫米
PE文件隐型加壳技术的研究与实现
No full text通过对PE(portable executable)文件格式的了解,编写PE分析工具对文件内部结构进行分析。详细介绍了对PE可执行文件加壳的全过程,在此过程中巧妙地使用MD5、CRC32等成熟的hash算法及防API断点跟踪等多种反破解技术,并采用自动隐藏加密方案,大大地提高了软件的保护力度
High-spin level structure in Mo-94,Mo-95
No full textHigh-spin level structures of 94,95Mo have been reinvestigated via the 16O(82Se, xnγ)94,95Mo(x = 4, 3)
reactions at E(82Se) = 460 MeV. The previously reported level schemes of these two nuclei have been largely
modified up to ∼11 MeV in excitation energy due to identifications of some important linking transitions. Shellmodel
calculations have been made in the model space of π(p1/2, g9/2, d5/2)4 and ν(d5/2, s1/2, d3/2, g7/2, h11/2)2(3)
and compared with the modified level schemes. The structures of the newly assigned high-spin states in 94,95Mo
have been discussed
Superfluidity in dense nuclear matter
No full textWe discuss the onset of superfluidity in neutron stars, where the model of nuclear matter
is realized in a high-density and asymmetry state. In particular, we present the study of the effects of
microscopic three-body forces on the proton pairing in the 1S0 channel and neutron pairing in 3PF1 channel
for β-stable neutron star matter. It is found that the main effects of three-body forces are to shrink the
domain of existence of the 1S0 below the threshold of the direct URCA process and to stretch the density
range of the 3PF1 pairing in a broad domain so to cover most part of the neutron-star core
Transition from the exhibition to the nonexhibition of negative differential thermal resistance in the two-segment Frenkel-Kontorova model
No full textAn extensive study of the one-dimensional two-segment Frenkel-Kontorova FK model reveals a transition
from the counterintuitive existence to the ordinary nonexistence of a negative-differential-thermal-resistance
NDTR regime, when the system size or the intersegment coupling constant increases to a critical value. A
“phase” diagram which depicts the relevant conditions for the exhibition of NDTR was obtained. In the
existence of a NDTR regime, the link at the segment interface is weak and therefore the corresponding
exhibition of NDTR can be explained in terms of effective phonon-band shifts. In the case where such a regime
does not exist, the theory of phonon-band mismatch is not applicable due to sufficiently strong coupling
between the FK segments. The findings suggest that the behavior of a thermal transistor will depend critically
on the properties of the interface and the system size
Superfluid nuclear matter in BCS theory and beyond
No full textMedium polarization effects are studied for S-1(0) pairing in nuclear matter within BHF approach. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. The self-energy effects always lead to a quenching of the gap, whereas it is almost completely compensated by the anti-screening effect in nuclear matter.NSFC 10875150
European Community Project Asia-Europe Link in Nuclear Physics and Astrophysics CN/ASIA-LINK/008(94791
Investigation of mechanical properties of material physics
No full text随着分子动力学模拟方法的发展，应力-涨落公式成为一种新
方法。和传统的理论方法相比，应力-涨落公式能够更有效的处
性质的影响。同时，由于应力-涨落公式中对原子应力的处理，
续非均匀系统。本文系统的研究了应力-涨落公式在分子晶体，
料力学性质计算中的若干问题。论文的内容可以概括为以下的六
第一章介绍了材料力学性质的研究和进展。对传统体材料力学
的纳米材料发展现状进行了介绍。
第二章介绍了力学性质研究的基本理论和方法。对连续介质力
方法和分子动力学方法都给出了具体的形式和推导。
第三章研究了应力-涨落公式在计算分子晶体力学性质时的若
使用应力-涨落公式计算分子晶体弹性常数时，由于热涨落效应
现较大误差。本章详细研究了这种误差的来源，并给出了解决方
第四章使用应力-涨落公式研究了贵金属的热学和力学性质
N-EAM 和 NN-EAM）和紧束缚势（TB-SMA）进行了参数拟合
以往的势函数相比，使用本文拟合的势函数计算出的贵金属热力
。
第五章中，应力-涨落公式被推广运用到纳米材料力学
nard-Jones 势和 TB-SMA 势为例，分析了两体势与多体势模型
响。并给出了不同纳米膜局域弹性常数的分布。同时，本章也研
温度对其力学性质的影响。
第六章对论文的各个章节进行总结概括
Synthesis and field emission of diamond-like carbon nanorods on TiO2/Ti nanotube arrays
No full textHighly ordered TiO2/Ti nanotube arrays were fabricated by anodic oxidation method in 0.5 wt% HF. Using prepared TiO2/Ti nanotube arrays deposited Ni nanoparticles as substrate, high quality diamond-like carbon nanorods (DLCNRs) were synthesized by a conventional method of chemical vapor deposition at 750 degrees C in nitrogen atmosphere. DLCNRs were analyzed by filed emission scanning electron microscopy and Raman spectrometer. It is very interesting that DLCNRs possess pagoda shape with the length of 3-10 mu m. Raman spectra show two strong peaks about 1332 cm (1) and 1598 cm (1), indicating the formation of diamond-like carbon. The field emission measurements suggest that DLCNRs/TiO2/Ti has excellent field emission properties, a low turn-on field about 3.0 V/mu m, no evident decay at 3.4 mA/cm(2) in 480 min. (C) 2009 Elsevier B. V. All rights reserved.National Natural Science Foundation of China 10774121
Natural Science Foundation of Gansu Province of China 0803RJZA102
Foundation of Northwest Normal University NWNU-KJCXGC-03-22
Foundation of Education Bureau of Gansu Province of China 0801-0
Pion Production in Heavy-Ion Collisions in the 1 A GeV Region
No full textWithin the framework of the improved isospin dependent quantum molecular dynamics (ImIQMD) model, pion emission in heavy-ion collisions in the region 1 A GeV is investigated systematically, in which the pion is considered to be mainly produced by the decay of resonances Delta(1232) and N*(1440). The in-medium dependence and Coulomb effects of pion production are included in the calculation. Total pion multiplicity and pi(-)/pi(+) yields are calculated for the reaction Au-197+(197) Au in central collisions for selected Skyrme parameters SkP, SLy6, Ska, SIII and compared with the measured data of the FOPI collaboration.National Natural Science Foundation of China 10805061
Special Foundation of the President Fellowship
West Doctoral Project of Chinese Academy of Sciences
National Basic Research Program of China 2007CB81500