80.9MeV 16O+27Al能量耗散和核子交换的关系

用带ΔE-E望远镜系统的飞行时间系统测量了80.9MeV ¹⁶O+²⁷Al反应出射产物的三重微分截面d³σ/dA dZ dE.对该反应中所出现的能量耗散和核子交换的关系进行了讨论.     

19F+51V耗散反应同位素类弹碎片的截面涨落

采用飞行时间(TOF)加△E-E探测系统,在102.25-109.50MeV(能量步长为250keV)的¹⁹T+⁵¹V反应中,第一次给出了耗散碰撞同位素产物的激发函数,讨论了双核系统的能量相干宽度Γ与产物的质量数A和Γ与产物的中子过剩自由度N/Z的依赖关系.     

14N+58Ni和14N+64Ni深部非弹性反应产物同位素分布的差异

实验测得¹⁴N(93兆电子伏)+⁵⁸Ni、⁶⁴Ni深部非弹性反应产物同位素分布, 发现这两者存在系统性的差异.     

北斗B1信号捕获跟踪算法的软件仿真研究

针对北斗B1频率的I支路信号,设计并实现了北斗软件接收机的基带处理部分。阐述了北斗B1频点信号的扩频体制和产生过程,并行码相位搜索捕获策略以及鉴相辅助跟踪环路,并设计了二阶数字环路滤波器,滤波器参数取ζ=0.707,B_n=25(Hz)。同时采用Matlab软件,仿真北斗中频数字信号,编码实现捕获跟踪算法,并分别通过对仿真信号和真实卫星信号的捕获跟踪,验证捕获跟踪算法的可行性,并提出锁频环辅助锁相环算法的改进思路。为进一步开展北斗软件接收机相关技术研究打下了基础。     

基于信噪比测量的欺骗干扰检测方法

在捕获北斗信号的过程中,接收机根据预先设定好的信号搜捕策略和门限值来捕获信号;欺骗干扰源通过产生虚假的相关峰和增加噪声基底,可以有效地干扰普通型北斗接收机正常的捕获工作;针对欺骗信号检测问题,在分析欺骗信号入侵对接收机噪声基底影响的基础上,提出了在捕获阶段利用信噪比(SNR)检测技术识别欺骗干扰信号的方法,并对其有效性进行了分析;仿真结果表明,采用该方法的接收机具有一定程度的欺骗干扰识别能力,为提高GNSS接收机抗干扰能力提供了有益的参考 。     

STUDY OF THE NUCLEAR PHENOMENA IN THE LOW ENERGY (60-360 keV) PROTON BEAM IMPLANTATION ON METALS

A series of studies on the nuclear interaction and its effects in solids during proton implantation were performed in the energy region between 60 and 360keV. Some charged particle products were observed in the implantation experiments on metal samples such as deuterated titanium, titanium alloy, titanium foil on molybdenum substrate, molybdenum and stainless steel, etc.. The energies of the charged particle products are about 3.9, 5.6 and 8.4MeV, respectively. These particles were identified as alpha particles with both detector telescope and absorption measurements. These three kinds of alpha products were found from different proton sub-barrier reactions. The exciting curve of this reaction increases exponentially with the growth of proton energy in the energy region from 90 to 330keV. The radiation damages induced by the nuclear products in the sample have been studied with scanning electron microscopy technique. The possible surface damages induced by them were observed evidently. The origin of the nuclear reactions and their effect on implantation are discussed.     

27Al+27Al耗散产物反应时间的提取

用发展了的Ericson统计理论,从²⁷Al+²⁷Al碰撞的耗散产物的激发函数提取了反应的相互作用时间约4.3×10^－21s.     

30MeV/u 40Ar+115In反应中的IMF能谱

测量了30MeV/u ⁴⁰Ar束流轰击¹¹⁵In反应靶时出射的中等质量碎片(IMF)的能谱.通过比较在不同出射角度发射的同一种IMF的能谱,得到了IMF的发射机制随出射角的演化关系.在假定运动源速度和出射离子库仑位垒不随出射角变化的条件下,通过改变发射源的强度和核温度参量完成了对实验测得能谱的运动源拟合,并详细讨论了3个发射源所占份额和源强随出射角的演化关系.     

重离子耗散反应产物激发函数研究的新进展

评述了近两年多来在重离子耗散反应激发函数研究中新的实验结果与理论进展.重点介绍27Al+2 7Al耗散反应产物的长程角度关联以及19F+93Nb耗散反应中截面及其涨落测量的不可重复性. The experimental study and the theoretical development on the structures of excitation functions in dissipative heavy ion collisions last years were reviewed. Especially the long range angular correlation in the reaction of 27Al+ 27Al and the non reproducibility of the cross sections measured in the reaction of 19F+ 93Nb were introduced. The experimental results indicate that the angular coherent width in the dissipative...     

二代高温超导带材的机械特性研究进展

以 YBCO(YBa2Cu3 O7 -δ ) 为代表的二代高温超导带材因具有高临界转变温度、 高临界磁场和强载流能力,受到了国际学界高度关注, 在各个领域具有广泛的应用前景. 二代高温超导带材在绕制、 冷却和运行过程中会受到不同来源的外力作用, 且超导带材的韧性、 延展性较差, 因此其机械性能是影响安全性与设备运行可靠性的关键.本文基于二代超导带材各向异性的特点, 对超导带材轴向、 横向、 弯曲三个方向的静态机械性能及疲劳性能进行了介绍. 同时, 也对超导带材各方向机械性能的测试方法、 影响因素及机理进行了总结