粗糙铂电极上甲醛电氧化行为及其现场表面拉曼光谱研究

利用循环伏安法研究了酸性介质中甲醛在粗糙铂电极上电氧化行为 ,考察了支持电解质浓度 ,电极表面结构等因素对甲醛氧化行为的影响 ,发现了甲醛在粗糙铂电极上的自发解离现象。采用共焦显微拉曼技术研究了甲醛在粗糙铂电极上解离吸附行为 ,获得了甲醛在该电极表面解离吸附的分子水平信息 ,并且从分子水平验证了甲醛在粗糙铂电极上的自发解离现象。     

超声波专题设计性实验

在测量超声波在空气中传播速度实验基础上,开设了超声波专题设计性实验,分别增加了测量压电换能器的共振频率、超声波在空气中的损耗系数、超声波在水中的传播速度等实验内容,丰富了大学物理实验教学内容,拓展了学生视野.     

BSO晶体的高温拉曼光谱与高温结构特征

阐述了BSO晶体在常温下的结构特征,通过测量晶体在常温下的拉曼光谱,对晶格主要振动模式进行了指认,测量晶体升温至熔化过程中不同温度下的拉曼光谱,分析研究了其微观结构在升温过程中的变化以及在高温状态下的结构特征。     

新书推荐——《神奇的粒子世界》

20世纪见证了物理学无与伦比的进步。在这个世纪的前半叶,基础物理由量子力学及爱因斯坦的相对论和引力理论所主导。而在后半叶,人类目击了基本粒子物理学的异军突起。在中国,尽管粒子物理学家已在实验和理论方面开展了许多工作,并且在世界粒子物理学领域占有了一席之地,但对于     

基于学习动机理论的高中物理演示实验教学策略

基于学习动机理论,探究了在演示实验教学过程中影响学习动机的内在因素,提出了激发学生内部学习动机的方法,并在此基础上提出了改进高中物理演示实验的教学策略,在理论上对物理演示实验教学的改进进行了反思和构建.     

圆环在抛物面上运动模式的分析与探讨

圆环在抛物面上的运动是一种错综复杂的刚体运动,涉及许多晦涩难懂的理论知识.本文首先在实验上呈现了圆环在抛物面上的运动,获得了不同初速度方向时圆环的运动模式,即直线型、三叶草型和螺旋型.通过运动模式构造了在xy平面内的衰减位移方程,较好的拟合了利用Tracker软件跟踪圆环获取的实验运动轨迹,并解释了初始速度方向与圆环运动模式之间的内在关联.最后,在纯滚动理论框架内,探讨了特殊运动模式下圆环的角速度.     

碱性介质中葡萄糖在铂电极上的阳极氧化

为了进一步探明葡萄糖在铂电极上的氧化机理 ,用循环伏安法 (CV)在 - 0 .9～ 0 .4V(相对于饱和甘汞参比电极 )内研究了葡萄糖在铂电极上催化氧化行为 ,首次详细报道了葡萄糖在电化学氧化过程中的电位振荡现象 ,并用电流扫描法表征了葡萄糖的电位振荡情况 .电流扫描结果表明 ,在较慢的电流扫描速度下 ,电极过程出现了明显的电位振荡 .说明电极上产生了毒化中间物 ,电位振荡是由于毒化中间物在电极上的吸附和在高电位下氧化除去引起的 .     

基于实践的初中物理课堂教学设计——以省级赛课“杠杆”教学为例

以学生为主体,实践活动为主线,引导学生探究和反思,使学生在体验中学到了知识,在实践中掌握了方法,在探究中提高了实践和创新能力,培养了物理核心素养.     

均匀带电平面折线在空间产生的电场及其可视化

推导了均匀带电线段在二维平面中产生的电势的简要公式,进而推导了在三维直角坐标系中的电势公式,形成了带电折线(包括任意多边形)的电势简要公式.根据电势与电场强度之间的关系,列出了场强的表达式.将公式无量纲化,利用MATLAB指令,绘制了各种形状的带电多边形和折线的等势面和三维电场线,并显示了电场在空间的分布规律.     

电磁波在左右手介质界面折射与反射特性的研究

研究了电磁波在左右手介质界面折射与反射的特性,给出了折射系数和反射系数,从另外一个方面探讨了最小作用量原理在左手材料中的适用性;从电动力学和最小作用量原理证明了Snell定律,验证了Snell定律在左手材料中的适用性,并且得到Fresnell公式在左右手材料中的一致性.     

基于Bootstrap-SVM在小样本条件下光谱定量分析研究

提出了一种在小样本条件下建立光谱定量分析的新方法-Bootstrap-SVM模型。以道路沥青为研究对象,共收集29个来自6个不同单位的沥青样本,利用所提方法建立了沥青针入度定量分析模型。Bootstrap-SVM由Bootstrap重抽样、噪声注入及SVM三个步骤组成。为了对比所提方法的优势,对比了目前常用的PLS模型以及SVM模型。研究结果表明Bootstrap-SVM,PLS,SVM预测均方根误差分别为0.773 5,2.889,1.784 4,所提方法预测精度最好,为小样本条件下光谱定量分析提供了一种新的有效方法。     

Analysis of an internal crack of pressure pipeline using ESPI and shearography

In this study, shearography and ESPI have been used for quantitative analysis of an internal crack of pipeline and both of them have proved to be suitable to qualitatively detect inside crack. However, shearography needs several critical? factors including the amount of shearing, shearing direction and induced load for the quantitative evaluation of the inside crack. In this study, the factors were optimized for the quantitative analysis and the size of cracks has been determined. Although the critical? factors in shearography have been optimized, it is difficult to determine the factors exactly because they are related to the details of cracks. On the other hand, ESPI is independent of the details of a crack and only the induced load plays an important role. The out-of-plane displacement was measured under the optimized load and the measured results were numerically differentiated, which resulted in an equivalent to the shearogram. The size of cracks can be determined quantitatively without any detail of a crack.     

Scattering properties of gradient heteropolymers obtained by “living” free-radical copolymerization

An original, quantitative, theory of “living” radical copolymerization has been developed proceeding from the current concepts of its kinetics and mechanism. This theory enables one to calculate both the dependence of monomers' conversion on time and any statistical characteristics of the chemical structures of the copolymers formed. Expressions have been derived describing the angular dependence of the scattering amplitude of the copolymerization products. The results of quantitative calculations of these characteristics have been also presented to exemplify the potentialities of the theory. Received 13 February 2001 and Received in final form 4 February 2002     

电荷注入检测器件的光谱特性和使用中应注意的若干问题

本文介绍了电荷注入器件（ＣＩＤ）的光谱特性,详细地讨论了低温状态下谱线定位和ＣＩＤ保护,分析谱线的选择,混合溶液制备一量分析的数据处理等问题。     

高谱分辨X光能谱诊断技术

采用国内首次研制出的2 000线/mm的自支撑透射光栅配上背照射软X光CCD(charge coupled device)组成了高谱分辨透射光栅谱仪。通过实验标定和理论模型计算相结合得到了高线对透射光栅的绝对衍射效率;同时建立了透射光栅谱仪测谱解谱方法,编制了相应的解谱程序。在“神光”激光装置上利用该谱仪通过激光打靶实验获得了金腔靶注入口发射的X光能谱定量实验结果,实验结果表明,该谱仪测谱范围在高能区达到6 000eV,谱分辨达到0.1nm,能够清晰地分辨金等离子体M带三峰分布X光谱结构。     

高谱分辨X光能谱诊断技术

 采用国内首次研制出的2 000线/mm的自支撑透射光栅配上背照射软X光CCD(charge coupled device)组成了高谱分辨透射光栅谱仪。通过实验标定和理论模型计算相结合得到了高线对透射光栅的绝对衍射效率；同时建立了透射光栅谱仪测谱解谱方法，编制了相应的解谱程序。在“神光”激光装置上利用该谱仪通过激光打靶实验获得了金腔靶注入口发射的X光能谱定量实验结果，实验结果表明，该谱仪测谱范围在高能区达到6 000eV,谱分辨达到0.1nm，能够清晰地分辨金等离子体M带三峰分布X光谱结构。     

Semiautomated quality assurance for quantitative magnetic resonance imaging.

It is now well established that MRI can be used for quantitative (as opposed to simply qualitative) measurements, and good accuracy and precision have been obtained in phantom experiments. To make routine quantitative measurements as part of a clinical scanning protocol, however, quality assurance (QA) methods particularly suited to quantification must be developed. We describe a set of QA tests using clinical protocols on test phantoms, with which we have assessed quantitative performance of our Picker 0.5-T scanner (Picker International, Cleveland, OH) over 2 years. We also describe the automated data processing methods we have developed to deal with the large amounts of data generated by these tests.     

高斯激光场中穿进轨道电子横向动量的阈值

采用数值模拟计算的方法,分析了强激光场中电子的动力学特性,发现穿进轨道电子的入射动量存在一定的阈值.通过研究穿进轨道电子的动力学特征,探讨了电子入射动量的阈值条件,发现与阈值相关的两个因素:激光强度和光束腰宽,推导了阈值的定标关系,结果显示:定标式与数值计算结果基本相符合.     

Ion-ion interactions in a polarized electron gas

Formally exact expressions have been derived for the response to a spin-dependent non-local pseudopotential and for the ion-ion interaction in a spin-polarized electron gas. These expressions have been compared to previously used expressions for these quantities and have been found to differ in several important ways. The improved expressions will make possible a quantitative investigation of the influence of a magnetic field on lattice properties of simple metals.     

Mixing properties of mim diodes in the infrared

Point contact MIM diodes of different materials have been tested as harmonic mixers at 29 THz and 88 THz. From the analysis of the I-V static characteristic quantitative informations have been obtained about the effectiveness of the diodes as high order mixers.