Effect of Precursor Molar Ratio of [S^2-]/[Zn^2＋] on Particle Size and Photoluminescence of ZnS：Mn^2＋ Nanocrystals

We investigate the influence of precursor molar ratio of [S^2-]/[Zn^2＋] on particle size and photoluminescence （PL） of ZnS：Mn^2＋ nanocrystMs. By changing the [S^2-]/[Zn^2＋] ratio from 0.6 （Zn-rich） to 2.0 （S-rich）, the particle size increases from nearly 2. 7nm to about 4.Ohm. The increase in the ratio of [S^2-]/[Zn^2＋] cadses a decrease of PL emission intensity of ZnS host while a distinct increase of Mn^2＋ emission. The maximum intensity for the luminescence of Mn^2＋ emission is observed at the ratio of [S^2-]/[Zn^2＋] ≈ 1.5. The possible mechanism for the results is discussed by filling of S^2- vacancies and the increase of Mn^2＋ ions incorporated into ZnS lattices.     

Schrǒdinger—cat态光场与耦合双原子相互作用系统的量子场熵演化

利用全量子理论，研究了Schrǒdinger-cat态光场与耦合双能级原子相互作用系统在非共振情况下的量子场熵演化特性．结果表明，场一原子系统的量子场熵演化特性不仅与初始平均光子数no、场与原子的耦合强度g、原子与原子之间的耦合强度ga以及失谐量△有着密切的关系，而且与原子的初始状态有关．     

双阶梯阴极型磁绝缘线振荡器设计与模拟

 结合负载限制型磁绝缘线振荡器（MILO）和渐变型MILO的特点,提出了一种新型双阶梯阴极型MILO。该器件前2个叶片为扼流片，中间3个叶片为主作用叶片,后面1个为提取叶片，在电流发射区与慢波结构径向相对的阴极部分分为3段，形成双阶梯阴极结构。根据Maxwell方程和Floquet定理导出其色散方程，并对其振荡主频作了理论分析。2.5维粒子模拟表明，器件工作频率为1.21 GHz，与理论预测相符，双阶梯的引入，对器件阻抗和振荡频率影响较小。在工作电压458 kV、电流40.5 kA条件下，双阶梯阴极结构将MILO输出功率从2.20 GW提高到2.88 GW，功率转换效率从12.0%提高到15.5%。     

基于多尺度Radon变换的图像检索

根据Radon变换的统计特性构造了不变量,提出一种新的基于多尺度Radon变换的图像形状检索方法.对检索图像作小波变换,根据小波模极大原理得到边缘图像,对边缘图像构造Radon变换中心矩,在中心矩的基础上根据Radon的统计原理构造出尺度不变矩.由于矩阵的奇异值具有旋转不变性,因此针对不变矩向量矩阵求奇异值,该奇异值特征向量具有平移、尺度和旋转不变性.将该Radon变换的不变量作为形状特征,并进行高斯归一化,按照欧氏距离计算不同图像间的形状相似度.试验结果表明,该方法对高斯噪音具有较强的鲁棒性,与其它方法相比具有较好的检索效果.     

Effects of Substrate Hydrophobicity/Hydrophilicity on Height Measurement of Individual DNA Molecules

Effects of substrate hydrophobicity/hydrophilicity on height measurement of individual ds-DNA molecules are investigated with tapping mode atomic force microscopy （TMAFM） and vibrating mode scanning polarization force microscopy （VSPFM）. The measured heights of ds-DNA on hydrophobic highly oriented pyrolytic graphite （HOPG） are remarkably less than those on hydrophilic bare mica and Ni^2＋ treated mica in both TMAFM and VSPFM. By analysing the results, we propose that the hydrophobicity/hydrophilicity of substrate can greatly influence the height measurement of DNA molecules.     

Applications of Extended Hyperbolic Function Method for Quintic Discrete Nonlinear Schr(o)dinger Equation

By using the extended hyperbolic function method,we have studied a quintic discrete nonlinear Schr(o)dinger equation and obtained new exact localized solutions,including the discrete bright soliton solution,dark soliton solution,bright and dark soliton solution,alternating phase bright soliton solution,alternating phase dark soliton solution,and alternating phase bright and dark soliton solution,if a special relation is bound on the coefficients of the equation.     

微乳液增敏光度法测定大米中的痕量铜

研究了溴化十六烷基三甲基铵(CTMAB)和正丁醇、正庚烷、水4组分构成的微乳液对铬天青S与铜(Ⅱ)显色反应的增敏作用,建立了测定大米中痕量铜(Ⅱ)的分光光度新方法.结果表明,在pH=6.00的NaH2PO4-NaAc缓冲溶液介质中,铜(Ⅱ)与铬天青S形成蓝绿色配合物,λmax=604 nm,表观摩尔吸光系数为6.608×104 L·mol-1·cm-1,在0-1.2 mg/L范围内吸光度与Cu2 浓度呈良好的线形关系,线性回归方程为:A=-0.01475 0.39036V,相关系数为r=0.9996.应用该方法对大米中的铜进行测定,相对标准偏差RSD=2.8%,加标回收率为97%-104%.结果表明,该方法具有较高的灵敏度、准确度与精密度,适合大米中痕量铜的测定.     

模糊二人零和对策的纳什均衡求解

用三角模糊数刻画二人零和对策支付值的不确定性,提出了计算模糊二人零和对策纳什均衡解的多目标规划方法.给出了一种基于区间数比较的三角形模糊数排序方法,根据该方法将模糊二人零和对策转化为多目标线性规划.通过一个数值实例说明了该方法的有效性和实用性.     

薄壁箱型结构吸收冲击能最大化的探讨

用薄壁箱型结构模型模拟在乘车空间不发生变形的条件下，发生正面冲突事故时车体．利用LS—DYNA程序分别地对附加质量附加在单个截面的模型、附加质量按照不同比例分配在两个截面的模型、改变前部分壁厚的模型进行冲击破坏模拟解析计算，根据其结果探讨在保持乘车空间的前提下如何增加前、后部冲击能的吸收问题．     

多种β射线阻挡层及X射线产额精度对BIXS技术的影响

氚分析在聚变堆与核技术的研究中有着广泛的应用。BIXS 技术(β 衰变诱发X射线谱技术)是一项无损的氚分析技术,该技术的分析深度对于高原子序数的材料能达到100 m,对低原子序数的材料能达到1 mm。在BIXS 技术中,采用金属薄膜作为β射线阻挡层具有排除极化韧致辐射干扰、减少探测器信号堆积等优点。为了研究多种β射线阻挡层材料对BIXS 技术的影响,利用Monte Carlo 方法PENELOPE 并行模拟程序分别模拟了采用Al、Au 金属薄膜和Ar 气作为β射线阻挡层的BIXS 技术,并使用GENEREG 反演程序对模拟结果进行反演计算及比较。还讨论了韧致辐射与特征X射线产额计算精度、韧致辐射谱倾斜对BIXS 技术的影响。研究表明Al 金属薄膜最适合用作BIXS 技术的β射线阻挡层。Tritium analysis has an extensive application in the study of fusion reactor and nuclear technology. β-decay induced X-ray spectroscopy (BIXS) is a nondestructive tritium analysis technique, and it can detect deeper tritium distributions (~0.1 mm and ~1 mm for high-Z materials and low-Z materials, respectively). In the BIXS method, a metal film as β-ray stopping layer has advantages of eliminating the interference of polarizational bremsstrahlung and reducing the detector’s signal pile-up. In order to study the effect of several β-ray stopping layers on the BIXS method, in this paper, we use the Monte Carlo code PENELOPE to simulate the BIXS experiments using Al, Au metal films and Ar gas as the β-ray stopping layers, and then use the regularization method to calculate and compare the results. In this paper, we also discuss the effects of accuracy of X-ray yield and bremsstrahlung spectrum incline on the BIXS method. The study in this paper indicates that the Al film is the best β-ray stopping layer in the BIXS method.