快速耦合光纤过程与半导体激光器电光特性实验的研究

详细地介绍了怎样快速耦合半导体激光器所发射激光与普通光纤输入端端面的方法,使耦合效率尽可能达到最大,并使用简单的方法测量了光纤的剩余长度或者测量光速,最后给出据测量半导体激光器电光特性曲线可准确方便地获得阈值电流的方法。     

MSC1210电源控制器的程序优化

为了解决兰州重离子研究装置( HIRFL ) 电源控制系统中的MSC1210 控制模块在调束过程中出现的各种故障,对其主芯片程序进行了优化设计。首先介绍了控制器的各种故障现象,分析了形成原因,然后制定了详细的设计方案,最后采用了以状态机为基础的指令接收过程、带校验机制的通信方式及远程指令复位等方法进行程序优化。实验室测试和现场使用结果表明,优化后的控制器运行稳定可靠,满足加速器的需求。The MSC1210 control module is one of the most important power supply controllers of Heavy Ion Research Facility in Lanzhou ( HIRFL ), but there are several problems during beam tuning. In order to deal with the problems,the main chip’s program was redesigned. In this paper we introduced the controller’s fault phenomena, and analyzed the reasons; then scheduled the optimized program in detail. Several methods were employed to improve the system performance, including instruction receiving process which is based on state machine, the communication mode with parity mechanism, and the remote instruction reset method. Both laboratory and commissioning tests indicate that the optimized controller is stable and reliable, and meet the operation requirement of HIRFL.     

Design and performance study of the LEPD silicon tracker onboard the CSES satellite

The low energy particle detector (LEPD) is one of the main payloads onboard the China seismic electromagnetic satellite (CSES). The detector is designed to ascertain space electrons (0.1-10 MeV) and protons (2-50 MeV). It has the capability of identifying the electrons and protons, to measure the energy spectrum and the incident angle of the particles. The LEPD is made up of a silicon tracker system, a CsI (Tl) mini-calorimeter, an anti-coincidence system made by plastic scintillator, as well as electronics and a data acquisition system (DAQ). The tracker is also a kind of E-E telescope; it consists of two layers of double-sided silicon strip detectors (DSSD). The signals emerging from the silicon tracker can be read out by two pieces of application specific integrated circuit (ASIC), which also can generate an event trigger for the LEPD. The functions of the DSSD system in the LEPD for charged particles were tested by 241Am @5.486 MeV α particles. The results show that the DSSD system works well, and has high performance to detect charged particles and measure the position of incident particles.     

A geometric factor calculation method based on the isotropic flux assumption

One of the instruments onboard the China Seismic Electromagnetic Satellite （CSES） is the Low Energy Particle Detector （LEPD）. The primary objective of LEPD is to provide measurements of the fluxes, energy spectra and pitch angles of 100 keV to 10 MeV electrons and protons from 2 to 50 MeV in the Earth＇s magnetosphere. The geometric factor is one of the principle parameters of a detector, which converts the physical quantity-count rate to the particle quantity-flux. In this paper, we calculated the geometric factor of LEPD via computer modeling of an isotropic radiation environment. It was first demonstrated that the radiation intensity related should obey a cosine-law, then a general sampling method of generating this distribution via GPS of GEANT4 was explained. Furthermore, combined with flux normalization, a comparison of the geometric factor calculation of a set of 2-layer detectors with different shapes （cylinder, truncated cone and rectangle） was performed. Results show a generally good agreement between simulation and analytical calculations for the cylinder and truncated cone detectors, and the result of the rectangular one, for which there is no accurate analytical formula, is consistent with the previous simulated results by others. As a practical instance of the 2-layer rectangle detector, the geometric factor of LEPD is 10.336±0.036 m cm2·sr for 10 MeV proton and 8.211±0.032 m cm2·sr for 8 MeV electron.     

室温下石墨烯的霍尔效应实验研究

对用化学气相沉积法(CVD)研制的长、宽均为1.23 cm,厚度为3个原子层尺寸的石墨烯样品,进行了室温下的霍尔效应相关研究。实验中电极与石墨烯之间有良好的欧姆接触。通过范德堡法测量了样品在磁场强度为0.353 T,不同电流强度下的霍尔电压,并对结果进行处理分析,得到石墨烯的霍尔系数RH=7.00×10-7m3/C、载流子浓度n=10.52×1024/m3、霍尔元件乘积灵敏度KH=6.87×102m2/C。     

硫酸中多气泡声致发光光谱

非线性声波方程与气泡脉动方程联立, 可以描述声空化云中的声场以及任何一个气泡的脉动过程,为数值计算空化场问题提供了理论框架.计算的声压分布变化可以用来计算单气泡动力学,了解任何位置处气泡发光过程以及气泡内气体温度和压强变化等. 对浓硫酸中氙气泡空化云的计算定性符合实验观测, 只有钠原子线谱的计算结果相比实验观测有些出入.     

基于近红外光谱的带种衣剂玉米种子真实性鉴定方法研究

应用近红外光谱鉴定玉米种子品种真实性已有深入的研究。在实际应用中,商品玉米种子均涂有种衣剂,给光谱的采集和分析带来了许多困难。提出了基于近红外光谱的带种衣剂玉米种子品种真实性快速鉴定方法。首先讨论了种衣剂对种子近红外光谱的影响,然后将种子沿着胚面凹陷方向切开,使用漫反射方式和专用配件测量种子切面的光谱,以消除种衣剂的影响。使用支持向量机、软独立模式识别和仿生模式识别三种方法建立四个玉米品种的真实性鉴定模型,正确识别率分别达到93%,95.8%和98%。品种鉴定模型具有很好的稳健性,对来自不同产地的同一品种的种子均能够正确识别。     

一类Kirchhoff方程Neumann边值问题解的存在性

考虑如下一类Kirchhoff方程Neumann边值问题:{-(a+b∫Ω(|↓△u|²+|u|²dx)(△u-u)+=c(x)|u|^q-2u+f(x,u)■u/■v=0,其中Ω■R^N是光滑有界域,c(x)可能是变号函数,a≥0,b>0且a+b>0,1相似文献   

组型为$2^u$的Kite-可分组设计的相交数问题

Kite-可分组设计的相交数问题是确定所有可能的元素对$(T,s)$, 使得存在一对具有相同组型 $T$ 的Kite-可分组设计 $(X,{\cal H},{\cal B}_1)$ 和$(X,{\cal H},{\cal B}_2)$ 满足$|{\cal B}_1\cap {\cal B}_2|=s$. 本文研究组型为 $2^u$ 的Kite-可分组设计的相交数问题, 设 $J(u)=\{s:\exists$ 组型为 $2^u$ 的Kite-可分组设计相交于$s$ 个区组\}, $I(u)=\{0,1,\ldots,b_{u}-2,b_{u}\}$,其中 $b_u=u(u-1)/2$ 是组型为$2^u$ 的Kite-可分组设计的区组个数. 我们将给出对任意整数 $u\ge 4$ 都有$J(u)=I(u)$ 且 $J(3)= \{0,3\}$.     

红参提取物总皂苷近红外定量分析建模中的变量筛选

注射用益气复脉（冻干）是由红参、麦冬、五味子3种药材制成的新型冻干粉针制剂。红参提取物总皂苷是注射用益气复脉（冻干）生产过程的重要质控指标,传统分析方法分析结果具有滞后性,无法快速反馈生产过程质量信息。近红外光谱(NIR)作为一种快速无损的过程监控工具已经广泛应用于中药质量控制领域。中药成分复杂且近红外光谱吸收强度弱、谱区重叠严重,如何从干扰严重的复杂光谱中提取有效信息是提高测量准确度的关键。模型集群分析（MPA）通过随机采样,最大限度地提取了样本信息,打破了传统一次性建模思路,为变量筛选方法提供了新的思想。采集了55批红参提取物近红外光谱数据,运用多元散射校正（MSC）进行光谱数据预处理,并将MPA衍生的随机蛙跳法（RF）、竞争自适应重加权（CARS）、变量组合集群分析法（VCPA）、VCPA联合迭代保留信息变量（IRIV）方法与OPUS软件自带的变量筛选方法分别用于总皂苷含量偏最小二乘（PLS）定量分析模型的建立中。结果表明,OPUS软件、CARS-PLS与RF-PLS所建模型校正集相关系数（R_c）仅为0.601 3,0.565 3与0.644 0,拟合效果不理想。VCPA-PLS法所建模型的R_c为0.951 2,是几种变量筛选方法中最高的,但是其预测性能不佳,模型稳健性不理想。VCPA-IRIV-PLS模型具有最好的预测效果,R_c为0.928,RSEP%为7.99%。