1D theory of laser plasma wake

In this paper, we get the 1D approximate analytical solution of the plasma electrostatic wake driven by the laser, and get the modified oscillating frequency of this wake. Finally we analyze the longitudinal beam dynamics in this electrostatic wake, and find that the high order terms don’t change the topology of the longitudinal phase space.     

催化动力学光度法测定痕量NO2^—的研究

本文研究了在稀硫酸介质中,ＮＯ２＾－对ＫＢｒＯ３氧化甲基橙褪色反应的催化作用及其动力学分析,建立了测定痕量ＮＯ２的新方法,该方法的检出限为１．３×１０＾－１０μｇ／ｍＬ,线性范围为０．－１．４×ｇ／１０ｍＬＮＯ２,方法简便、灵敏、选择性好,于水及蔬菜中痕量ＮＯ２的测定,结果满意。     

为学生的课堂行为进行教学设计

<高中物理课程标准>指出:在课程实施方面,应促进学生自主学习,让学生积极参与、乐于探究、勇于实验、勤于思考;通过多样化的教学方式,帮助学生学习物理知识与技能,培养科学探究能力,使其逐步形成科学态度与科学精神.基于此,物理课堂教学的基本任务,就是通过教师的组织、引导,让学生掌握前人积累下来的知识,在提高科学素养的基础上开展创造性活动,不断使学生学会学习.     

Design studies on the ERL-FEL test facility at IHEP, Beijing

A proposed compact ERL test facility at IHEP, Beijing, is presented in this paper, and includes the design parameters, the essential lattice, and the key components features, such as the photocathode DC gun and the CW superconducting accelerating structures. Some important beam physics issues such as the space charge effect, the coherent synchrotron radiation (CSR) effect and the beam break-up (BBU) effect are briefly described with the simulation results.     

Experimental study on SC RF cavities by using China large grain niobium for ILC

Large grain niobium has the potential of simplifying the production sequence and consequently reducing the cost of the superconducting RF cavities for ILC. To investigate the feasibility of fabrication and the possibility to achieve high gradient by large grain cavities, two 1.3GHz cavities were made of China large grain niobium and a series of vertical tests were carried out following several different surfaces treatment procedures. Two cavities have both reached the high gradient of more than 43MV/m repeatedly and the maximum accelerating field of 47.9MV/m has been achieved by China large grain niobium. This paper introduces the features of the fabrication and surface treatments on the large grain cavities and presents the preliminary results of the research.     

多官能团化的1,5-苯并二氮杂■类化合物的绿色合成

1,5-苯并二氮杂■类化合物是一类具有重要生物或药理活性的七元氮杂环化合物,酯基、羧基、酰基、芳基等均是其活性基团.在室温(25℃)下以醛羰基化合物或二羰基化合物、3-丁炔-2-酮、取代的邻苯二胺为原料,无水乙醇为溶剂,磁性纳米铁酸钴(CoFe₂O₄)为催化剂/无催化剂条件下三组分串联反应一锅绿色合成34种COR、COOR或COOH取代的1,5-苯并二氮杂■类化合物,产率最高可达90%,并提出了催化串联合成反应机理.该串联反应历经迈克尔加成反应、亲核加成反应、脱水反应、分子内的亚胺-烯胺环合反应、质子转移等反应过程,一个反应体系内合成了多官能团化的1,5-苯并二氮杂■化合物,实现了温和条件下,一个反应体系中在苯并二氮杂■的七元环上同时引入活性的酰基、酯基或羧基等多个活性基团.该方法的优势在于合成方法新颖、原子经济、目标化合物产率及选择性较高,实现了反应过程的绿色化,为绿色合成苯并氮杂■类化合物提供了新思路.     

Effects of machine errors on the ILC main linac

For a practical linac, the beam property is affected seriously by any machine imperfections. In this paper, the effects of several main errors in the ILC main linac, such as quadrupole misalignment, magnet strength error and cavity misalignment, were studied by a theoretical method. The tolerance for each error was also obtained. Comparison with the numerical simulation result is made and the agreement is quite good.     

1.3GHz单cell高梯度低损耗超导腔设计研究

计划中的国际直线对撞机(简称 ILC), 已确定采用低温超导技术. 研究表明, ILC的整体造价与超导腔的加速梯度密切相关, 因此新型高梯度超导腔的研制, 已成为目前ILC的热门课题. 目前超导腔加速梯度的提高受限于超导体射频临界磁场(H_c^rf), 希望通过腔形的优化设计, 来减小超导腔表面峰值磁场与加速梯度的比值(H_p/E_acc), 进而提高超导腔的加速梯度, 以满足ILC的要求. 目前, 具有代表性的高梯度超导腔新腔形有两种, 即低损耗超导腔(LLSCC)和重入式超导腔(RESCC). LLSCC相对于RESCC而言, 具有较低的H_p/E_acc, 因此在理论上LLSCC更易于达到较高的梯度. 作者对1.3GHz单cell高梯度低损耗超导腔的腔形进行了详细的研究, 给出了相应低损耗超导腔腔形, 并对这一设计结果进行了分析比较.     

BEPCⅡ小动量压缩因子模式研究

BEPCⅡ是BEPC的升级工程, 它被设计工作在亮度为10³³cm^－2.s^－1的τ-charm能区.为了提高BEPCⅡ的运行亮度,研究了BEPCⅡ对撞模式的小动量压缩因子模式.同时优化了这个模式下的动力学孔径和模拟计算了这个模式的亮度.     

聚合硫酸铁絮凝剂中痕量镉分光光度法测定研究

本文研究了分光光度法测定聚合硫酸铁絮凝剂中痕量镉的新方法并探讨了显色反应机理。本法是利用分光光度法测定聚合硫酸铁絮凝剂中痕量镉。显色剂为罗丹明B和碘化钾。表面活性剂为聚乙烯醇(PVA)。光度显色反应灵敏度高 ,其最大吸收波长为 60 7nm。表观摩尔吸光系数为 4 99× 1 0 5L·mol- 1 ·cm- 1 。桑德尔灵敏度为 2 2 5× 1 0 - 4 μgCd(Ⅱ )·cm- 2 。镉含量在 0～ 1 5 μg·2 5mL- 1 范围内服从比尔定律。回收率为 96%～ 1 0 5 %。方法操作简便 ,不需要萃取分离 ,可在水相中直接测定 ,故大大简化了操作手续。用本法测定了聚合硫酸铁絮凝剂中的痕量镉 ,得满意效果