Cold Nuclear Matter Effects on Isolated Prompt Photon and Isolated Prompt Photon+Jet Productions in Relativistic Heavy-Ion Collisions

We investigate the cold nuclear matter(CNM) effects on isolated prompt photon and isolated prompt photon associated jet productions in nuclear collisions at the NLO accuracy by using the EPS09 NLO nuclear parton distribution functions and their error sets.Nuclear modification factors of isolated prompt photon and isolated prompt photon+jet productions due to CNM effects in p+A and A+A reactions at the RHIC and the LHC are provided with varying rapidity and transverse momentum of the final state photon.It is shown that the CNM effects on isolated prompt photon and photon+jet are modest,which give a small enhancement at low pT region and a more obvious suppression at large pT at central rapidity.At forward rapidity a pronounced suppression of γ as well as γ+jet is always observed.     

Prompt neutron multiplicity distribution for ~（235）U（n,f） at incident energies up to 20 MeV

For the n+²³⁵U fission reaction, the total excitation energy partition of the fission fragments, the average neutron kinetic energy <ε>(A) and the total average energies E_γ(A) removed by γ rays as a function of fission fragment mass are given at incident energies up to 20 MeV. The prompt neutron multiplicity as a function of the fragment mass, ν(A), for neutron-induced fission of ²³⁵U at different incident neutron energies is calculated. The calculated results are checked with the total average prompt neutron multiplicities ν and compared with the experimental and evaluated data. Some prompt neutron and γ emission mechanisms are discussed.     

高空核爆炸瞬发辐射电离效应的数值模拟

采用蒙特卡罗方法模拟了高空核爆炸瞬发辐射中子、γ射线、X射线电离大气的过程,给出了几种爆炸场景下瞬发辐射产生的附加电离电子密度空间分布.针对大气密度随高度非均匀连续变化的特性,采用质量距离抽样方法取代常用的步长抽样方法,无需根据大气密度随高度的变化进行分层处理,提高了计算效率.结果表明:对于不同的爆高,瞬发辐射电离分布存在显著的差异;随着爆高的增加,瞬发辐射附加电离区范围增大,但电子密度的峰值减小. 关键词： 高空核爆炸 瞬发辐射 大气电离 蒙特卡罗方法     

Erste Ergebnisse zur Anwendung der prompten Gammastrahlung im Hinblick auf die vor Ort Anwendung in der Bauzustandsanalyse

Im Hinblick auf eine vor Ort Anwendung auf dem Gebiet der Bauwerksdiagnostik stellt die vorliegende Arbeit erste Ergebnissc vor, die unter Ausnutzung der prompten Gammastrahlung erzielt wurden. Dabei werden ausschlieβlich, unelastische Streuprozesse schneller Neutronen an der Probenmatrix betrachtet. Dic Anregung erfolgte mit einer ²³⁸Pu/Be-Neutronenquelle mit einem Neutronenfluβ von ca. 5 × 10⁷ s^?1 und die Registrierung der prompten Gammastrahlung mit einem NaI(Tl)-Kristall. Besonderes Augenmerk galt den Elementen Mg, Al, Si und Fe als qualitätsbeeinflussende Parameter des Betons.

This publication is a contribution to the application of nuclear metltods in civil engineering. In view of in situ determination of elements in walls of concrete the first results of applying prompt gamma radiation, due to inelastic scattering of fast neutrons in the sample are shown. The stimulation of prompt gamma-rays is carried out by means of a ²³⁸Pu/Bneutron source with a flux of neutrons of about 5 × 10⁷ s^?1 and the detection of gamma radiation by means of a Nal(Tl)- deteclor. The elements Mg, Al, Si and Fe as the parameters of quality of concrete were the elements of interest.     

Calculation of prompt fission neutron spectrum for 233U（n,f） reaction by the semi-empirical method

The prompt fission neutron spectra for the neutron-induced fission of 233U for low energy neutrons （below 6 MeV） are calculated using nuclear evaporation theory with a semi-empirical method, in which the partition of the total excitation energy between the fission fragments for the nth＋233U fission reactions is determined by the available experimental and evaluation data. The calculated prompt fission neutron spectra agree well with the experimental data. The proportions of high-energy neutrons of prompt fission neutron spectrum versus incident neutron energies are investigated with the theoretical spectra, and the results are consistent with the systematics. The semi-empirical method could be a useful tool for the prompt evaluation of fission neutron spectra.     

脉冲源法测量次临界系统裂变衰减特性的理论分析和数值模拟

针对点堆动力学理论解释脉冲源法测试原理时存在的问题, 基于无源中子输运方程分析次临界系统总中子数、泄漏γ射线计数率随时间的变化关系。理论分析表明: 脉冲中子源作用结束后(无源条件下), 在一定时间范围内, 泄漏γ射线计数率和总中子数近似成正比, 两者随时间变化服从近似指数衰减规律, 反映系统本身的裂变衰减特性, 可以由总中子数和γ射线计数率求解瞬发中子衰减时间常数。基于蒙特卡罗程序构造类Godiva裸铀球次临界系统, 模拟脉冲中子源作用下中子和γ射线输运过程, 计算总中子数、泄漏γ射线计数率及两者比值随时间的变化关系, 结果与理论分析一致; 利用脉冲源法由总中子数、泄漏γ射线计数率计算瞬发中子衰减时间常数α₀, 得到与α-k迭代一致的α₀。说明总中子数、泄漏γ射线计数率可以准确反映系统本身的裂变衰减特性。此外, 根据理论分析和模拟计算给出脉冲源法可用数据的时间范围, 分析泄漏γ射线计数率和总中子数比值的影响因素。     

麝香百合组培快速繁殖技术研究

通过对百合球茎鳞片离体组织培养的研究,探讨了丛生芽诱导、继代增殖培养、生根培养及移栽等方面的组培快速繁殖以及生产上实用的组培技术,结果表明,MS 6-BA3.0mg\L NAA0.5mg\L KT0.14mg\L 2.4-D0.3mg\L 蔗糖35mg/L为适宜的诱导培养基,其诱导率为92%;MS 6-BA2.5mg/L NAA0.5mg/L KT0.1mg/L 2.4-D0.2mg/L 蔗糖65g/L为最佳的继代增殖培养基,其繁殖倍数为10.9倍,1/2MS NAA1.0mg/L 蔗糖35g/L的培养基诱导生根效果较好, 其生根率为86.7%,移栽成活率为100%,这为麝香百合大规模工厂化育苗提供了理论依据和技术保证。     

OOP在Delphi开发中的应用

为解决Ｄｅｌｐｈｉ中文提示的两种方法－增加操作和继承，说明了在面向对象的编程环境中，应充分应用面向对象的程序设计思想。     

数字媒体技术专业教学质量保障体系建设的研究

专门的数字媒体技术专业教学质量保障体系由数字媒体技术专业教学质量评分标准、数字媒体技术专业教学质量阶段评价系统、数字媒体技术专业教学质量实时改进机制三部分组成,该套体系能够将数字媒体技术专业教学质量进行量化,及时发现并改正教学环节中的问题,保障数字媒体技术专业的教学质量。     

Multiplicity distribution of prompt gamma rays in spontaneous ternary fission of252Cf

The first and the second moments of the multiplicity distribution of prompt gamma rays in spontaneous ternary fission of²⁵²Cf have been measured by the multiple coincidence technique. While both these moments were found to be nearly independent of the energy of the light charged particle accompanying the fission fragments, the width of the multiplicity distribution was larger than that in the case of normal binary fission by about 20%.