A possible approach to reduce the emittance of HLS-Ⅱ storage ring using a Robinson wiggler

In this paper, we present some preliminary studies on using a Robinson wiggler to reduce the horizontal beam emittance in the Hefei Light Source Ⅱ (HLS-Ⅱ) storage ring. A proof-of-principle lattice demonstrates that it is possible to reduce its emittance by 50% with a 2-meter long wiggler. This encouraging result suggests a feasible option to significantly improve the machine performance at a relatively low cost.     

基于PXI总线便携式万用测试仪的设计

随着电子工业和军事工业的快速发展,对各种各样复杂信号测试的需求日益增多。尤其是在多信号、多频段、多变量的测试环境中,可能会需要多用表、任意波形发生器、示波器、射频信号源、音频分析仪和频谱分析仪等多种测试仪器中某几种仪器的同时使用。设计一款采用PXI总线硬件架构的高性能便携式万用测试仪,它在一台便携式仪器中集成了常用9种通用仪器测试功能,能够满足现场对多种类型信号同时测试的实际需求,在很大程度上提高了测试效率。     

A betatron tune measurement system based on bunch-by-bunch transverse feedback at the Duke storage ring

To combat electron beam instabilities, a digital bunch-by-bunch transverse feedback (TFB) system has been developed for the Duke storage ring. While it is capable of suppressing transverse beam instabilities for multibunch operation, the TFB system has not been needed for typical operation of the Duke storage ring. To explore the great potential of this system, we have developed beam diagnostic techniques using the TFB, in particular, the TFB based tune measurement techniques. The tune measurement technique allows us to conduct fast chromaticity measurements, compared with the existing chromaticity measurement system using a network analyzer. This new tune measurement system also enables us to measure the bunch tune for multibunch operation of the Duke storage ring. With the TFB based tune measurement system, we have studied the tune stability of the electron beam in the Duke storage ring. This tune system has also been used to calibrate the tune knob for the Duke storage ring.     

中考一轮复习＂一次函数复习＂教学设计

这是一节我市2013年九年级数学复习教学主题教研活动中的研究课,为了更好地体现新课程背景下的复习课教学和这次活动的“关注学生学习,提高复习效率”的主题,笔者将重点放在正确理解新课标和准确把握复习内容上,突出第一轮复习学科知识的基础性、系统性和巩固性,重点关注复习课教学中师生活动的设计．整节课沿着学生对知识的回忆实例出发,使学生对一次函数概念、一次函数的解析式和一次函数的图像性质有更进一步的认识,     

A waveguide overloaded cavity kicker for the HLS Ⅱlongitudinal feedback system

In the upgrade project of Hefei Light Source(HLSⅡ),a new digital longitudinal bunch-by-bunch feedback system will be developed to suppress the coupled bunch instabilities in the storage ring effectively.We design a new waveguide overloaded cavity longitudinal feedback kicker as the feedback actuator.The beam pipe of the kicker is a racetrack shape so as to avoid a transition part to the octagonal vacuum chamber.The central frequency and the bandwidth of the kicker have been simulated and optimized to achieve design goals by the HFSS code.A higher shunt impedance can be obtained by using a nose cone to reduce the feedback power requirement.Before the kicker cavity was installed in the storage ring,a variety of measurements were carried out to check its performance.All these results of simulation and measurement are presented.     

“阴影面积”型中考试题解法例析

近几年来，全国各地的中考卷中频频出现“阴影面积问题”的试题，逐渐成为中考命题的一个热点问题，这类试题题型较多，解题方法也颇为讲究．     

Design and optimization of a longitudinal feedback kicker cavity for the HLS-Ⅱ storage ring

In the Hefei Light Source (HLS) storage ring, multibunch operation is used to obtain a high luminosity. Multibunch instabilities can severely limit light source performance with a variety of negative impacts, including beam loss, low injection efficiency, and overall degradation of the beam quality. Instabilities of a multibunch beam can be mitigated using certain techniques including increasing natural damping (operating at a higher energy), lowering the beam current, and increasing Landau damping. However, these methods are not adequate to stabilize a multibunch electron beam at a low energy and with a high current. In order to combat beam instabilities in the HLS storage ring, active feedback systems including a longitudinal feedback system (LFB) and a transverse feedback system (TFB) will be developed as part of the HLS upgrade project, the HLS-Ⅱ storage ring project. As a key component of the longitudinal bunch-by-bunch feedback system, an LFB kicker cavity with a wide bandwidth and high shunt impedance is required. In this paper we report our work on the design of the LFB kicker cavity for the HLS-Ⅱ storage ring and present the new tuning and optimization techniques developed in designing this high performance LFB kicker.     

HLS-Ⅱ直线加速器能量调节及应用

为了高效地对直线加速器输出束流能量进行调节,设计了合肥光源（HLS-II）直线加速器束流能量调节方案。该方案在调试阶段通过能谱分析系统观察束团状态并测量束流能量,储存环注入阶段使用3个束流位置探测器（BPM）对束流能量进行在线测量;使用自动相位扫描程序对速调管输出相位进行扫描,获得各加速段的能量增益公式;定量调节速调管的输出相位和高压,实现直线加速器输出束流能量的快速调节。在线应用结果表明,该方案能快速实现束流能量调节,调节后的束流具有良好品质,束流横向能散小于0.22%,注入速率明显改善。     

一种手持式超高频RFID读写器检测仪的设计

射频识别（RFID）技术随着物联网的兴起而得到迅速发展,超高频RFID技术因其识别距离远、识别速度快、有较强的防碰撞能力而被广泛应用。与RFID技术相比,RFID测试技术相对比较滞后,RFID测试还主要是基于参考标签或参考读写器的定性测试。为了实现RFID读写器的射频参数和协议一致性的定量测试,设计了一种基于射频处理和软件无线电（SDR）的超高频RFID读写器检测仪。该检测仪属于手持式设备,体积小、功耗低、重量轻、功能强大、且操作简便,满足超高频RFID读写器批量生产和现场保障的测试需求。     

非扩张映像不动点的一种变形迭代算法

在Hilbert空间的框架下,用一种变形的迭代格式xn+1=αnf(xn)+βnxn+γnTxn,研究一闭凸集合C上的非扩张映像的不动点问题,当满足适当的条件,且n→∞时,{xn}强收敛至T的一个不动点,并且此点也是某变分不等式的解.去掉了一些作者提出的相应条件,其结果改进了相应文献的一些近代结果.