池水瞬态闪蒸时间的实验研究

实验研究了过热度、初始水温及水位高度对方腔内池水瞬态闪蒸时间的影响.实验条件为:水位高度40 mm、60mm、100 mm,初始水温36～88℃,过热度2.1～48℃.实验结果表明:过热度及水位高度是影响闪蒸时间的主要因素,过热度及水位高度越大,闪蒸时间越长;过热度相同时,初始水温对闪蒸时间的影响很小.通过对实验数据分析,拟合出瞬态闪蒸时间的计算关联式.     

A prototype of a high rating MRPC

Six-gap resistive plate chamber (MRPC) prototypes with semiconductive glass electrodes (bulk resistivity～1010.cm) were studied for suitability in time-of-flight (TOF) applications at high rates. These studies were performed using a continuous electron beam of 800 MeV at IHEP and an X-ray machine. Time resolutions of about 100 ps and efficiencies larger than 90% were obtained for flux densities up to 28 kHz/cm2.     

高强高效近红外光源的不同光源强度对玉米杂交种鉴别的影响

以2009年产自海南的农华101玉米种子作为研究对象,基于近红外漫透射光谱法(波长范围908.1~1 677.2 nm),研究了一种高强高效近红外光源在不同光源电压以及光源至光谱仪不同距离两种条件下对玉米杂交种鉴别的影响。对光谱进行一阶导数、矢量归一化的预处理后,使用主成分分析(PCA)和正交线性判别分析(OLDA)提取光谱特征,使用支持向量机(SVM)分别建立种子纯度鉴定模型,统计不同实验条件下的识别率。结果表明,在电压较低或者光源至光谱仪的距离较大的时候,光源强度较低,得到的光谱曲线有较多的毛刺,此时的识别率较低,增大电压或者降低光源至光谱仪的距离时,光谱曲线变得较为平滑,识别率明显升高,说明在一定范围内增大光源强度会提高模型的正确鉴定率。     

基于分数阶傅立叶变换的线性调频回波参数估计

本文提出了一种适用于宽带线性调频回波的分数阶傅立叶变换参数估计方法。它通过寻找合适的信号代替发射信号做模版,使得模版信号与接收信号的模糊函数匹配度高,峰值尖锐,失真率低。再利用分数阶傅立叶变换与模糊函数的关系,使用两次分数阶域的峰值搜索代替原有的一次二维搜索降低计算量。仿真实验结果表明,本文提出的方法在精确估计宽带回波的时延和频移的同时降低了计算复杂度。     

新疆紫穗槐中总黄酮的提取与含量测定

用超声波辅助乙醇溶液浸提法和索氏提取法提取新疆地方植物药材紫穗槐中黄酮化合物并进行含量测定.以芦丁为对照品,NaNO2-Al(NO3)3-NaOH体系为显色剂,利用分光光度法在510nm处测定提取物中的总黄酮的含量.校准曲线为A=11.825C-0.0139,r=0.9992.超声提取法所得总黄酮的含量以芦丁计算为2....     

光谱法研究水团簇结构对AlCl3溶液与血清白蛋白作用的影响

研究了冷冻-解冻处理对A1CI₃溶液团簇结构和AICl₃与血清白蛋白相互作用的影响。测定了AICl₃溶液冷冻-解冻处理前后电导率的变化,发现AICI₃溶液经冷冻处理后,电导率有明显增加。采用紫外分光光度法和荧光光谱法对冷冻前后AICI₃溶液与血清白蛋白相互作用的研究表明,A1C1₃溶液经冷冻-解冻处理后,与血清白蛋白的相互作用变弱,配位诱导作用降低,静态猝灭作用变小,这种相互作用变弱的效应是由于水的分子团簇结构变化引起的。     

Symmetry Groups and Exact Solutions of New （4＋1）-Dimensional Fokas Equation

In this paper, we investigate symmetries of the new （4＋1）-dimensional Fokas equation, including point symmetries and the potential symmetries. We firstly employ the algorithmic procedure of computing the point symmetries. And then we transform the Fokas equation into a potential system and gain the potential symmetries of Fokas equation. Finally, we use the obtained point symmetries wave solutions and other solutions of the Fokas equation. and some constructive methods to get some doubly periodic In particular, some solitary wave solutions are also given.     

水平方管层流混合对流的三维数值模拟

本文建立了水平矩形通道三维层流混合对流的数学模型,提出了壁面导热与流动耦合的简化计算方法,采用SIMPLER算法对其流动和换热过程进行了数值模拟.计算结果表明由于浮升力的作用使水平通道内出现二次流现象,加热面的上下顶端周向导热热流密度存在极大值,下底面的局部Nusselt数最大,上底面最小.混合对流:平均Nusselt数随 Re和Gr*的增大而增大;但当Re较大时,平均Nusselt数随Gr*变化而近似不变.     

Study of Ternary Fission Produced in 12C Bombarding 209Bi Target with Medium Energy

Alternative layers of target material,which were prepared by evaporating ²⁰⁹Bi on the surface of mica foils,were irradiated with ¹²C ions.Ternary fission events in which three fragments of comparable mass were produced in 2525－47.5MeV/A ¹²C+²⁰⁹Bi reaction,were recorded by the mica detectors with 2π geometry.The observed probability ratio of ternary fission relative to binary fission in 2π geometry was modified to 4π geometry spatial in terms of the Monte Carlo method.The values of ratioes increase with the bombarding energy,and are compared with the calculation result of the cascade fission model.