高校普物实验“全息照片拍摄”的一个改革教案

本文报道了复旦大学普物实验“全息照片拍摄”的一个改革教案,在实验中，对同一拍摄对象按不同的曝光量在底片的四个区域拍摄四次，一次冲洗，从而可快速稳妥地找到正确的曝光参数，大大减少了实验中大量重复的拍摄、冲洗过程，节约了照相材料和时间．同时在同一底片的四个区域可观察到四个全息象，增强了学生对全息照片的感性认识．     

高速摄影在偏心轴压下缺陷圆柱壳弹性稳定性研究中的应用

本文介绍了用NACE—10高速摄影机拍摄在偏心轴压下对具有初始缺陷圆柱壳进行弹性稳定性的试验研究,较详细地记录了圆柱壳体加载到某一定值时,模型失稳产生层曲的瞬间以及拍摄过程中所遇到的困难和相应解决这些困难的方法。 在实际拍摄中主要有两点困难:     

高速摄影拍摄旋转叶片振动

叶片在高速旋转过程中会产生振动,目前测量方法很多。我们用高速摄影的方法拍摄高速旋转的叶片的振动比较直观,也能获得定量的结果。在不同的拍摄方法中用狭缝连续拍摄法较满意,能获得叶片的随机振动。本文着重介绍几种拍摄方法的对比和狭缝摄影法的数据处理方法。     

高速摄影在内燃机燃烧过程研究中的应用

本文首先介绍了用高速摄影机拍摄定容燃烧弹模拟分层充气发动机的燃烧过程。其次介绍拍摄燃烧室形状不同的直喷式汽油发动机气缸内的气体流动和燃烧过程。气体流动用外加白色膨化聚笨乙烯球形粒子示踪、粒子直径为1毫米,比重为0.256g/cm³。通过对摄影胶片的判读分析,获得了重要的试验结果。文中还介绍了在同一画幅上同时记录气缸内示踪粒子运动或点火燃烧过程,以及表征活塞位置的飞轮转动标记的摄影光学系统。文章附有高速摄影得到的照片序列。     

一种点阵码的自动识别方法

对电影经纬仪和高速摄影机所拍摄胶片的阵列码点分布形式进行了分析，建立了基于点间描述和点描述的模型。介绍了一种码点自动识别简便算法，基于所建立点描述模型．采用对比度和空间判据对阵列码点进行识别．讨论了判据中可变参数调整对各种码点缺陷的适应性。针对拍摄条件恶劣和冲洗存放不当导致的成像劣化胶片．可用该方法完成准确判读。与经典的阈值方法作以比较．发现该方法有很好的判读适应性．且不易产生误漏判．误帧率小于1／1000。     

紫外反射照相的机理及公安应用

紫外反射照相是利用目标反射或吸收紫外线的差异来拍摄的照相．它在刑事侦察和法庭鉴定中有特殊作用，近年来成为发达国家法庭科学一种新颖手段．本文介绍它神奇功能的三个特点．紫外反射照相的机理是皮肤中黑色素物质对紫外线的吸收作用和皮下肌肉对紫外线的反射作用，两种作用的结合在底片上形成反差．利用常规的和专用的照相器材，可拍摄到这种照相．     

科技照相的实验方法

介绍了科技照相实验中有关拍摄技术方面的内容和通过翻拍资料、静物摄影、动态摄影中各技能环节的训练，使学生在实验能力、分析能力、观察能力上有所提高．     

超短脉冲激光选通电子学全息成象系统研究

本文介绍了最早到达光概念，分析了超短脉冲激光电子学全息实现选通最早到达光成象的原理．用超短脉冲激光拍摄全息图，相当于用多色光记录全息图，当用单色光再现这种全息图时，会给再现象造成一个模糊量．在一般全息理论中，只讨论了采用单色光记录全息图，复色光再现所造成的模糊量．因此，本文中讨论的是一个与此相反的问题，即用多色光记录全息图，单色光再现的情况，并且着重讨论了超短脉冲激光记录全息图的情况．最后得出结论，在用超短脉冲激光拍摄全息图时，最好采用象面全息术．     

在科技照相实验中应该使用数码相机

近年来，随着计算机技术的迅猛发展，照相机工艺与计算机之间出现了一种崭新的联系─—数码相机．在信息时代，把具有先进技术的数码相机引入科技照相实验中，将给实验带来更新的活力． 数码相机与传统相机主要区别就在于去掉了一系列复杂的拍摄、冲洗、印相过程，只需要与其相匹配的计算机相连，在计算机上就可以随心所欲地使拍摄的相片光彩夺目，姿态万千．数码相机不用胶卷，而是将光信号转化为电信号，再经过模／数转换后记录于存储卡上，存储卡还可以反复使用，在使用数码相机时，可以随拍随观察拍摄效果，如果认为不理想，可以立即删…     

环氧丙烷爆燃转爆轰过程中产物C2的发射光谱

采用具有增强功能的光谱探测器增强型电荷耦合器件(Itensified charge coupled device,ICCD)和自行设计的光电转换器,应用激波管技术对环氧丙烷爆燃转爆轰过程的发射光谱进行了拍摄,探测器快门开启时间为2μs,在500-570nm之间进行了多次测量,由压力传感器监测的压力信号来判断爆燃转爆轰过程的重复性。实验结果表明：探测到了产物C2分子的发光光谱,它们可归属为斯旺(Swan)带的d^3∏g-a^3∏u跃迁中△v=-1.0的两个振动序列。各序列的带头分别为516．52nm,512．94nm,563．55nm,558．55nm,554．07nm,550．19nm和544．77nm。通过对所拍摄光谱的分析,推断中间产物C2是环氧丙烷爆燃转爆轰过程中的主要产物之一,并给出了C2自由基形成的几种可能的反应通道。     

A study on the best irradiation dose of X-ray for Hep-2 cells by Fourier transform infrared spectroscopy

Fourier transform infrared spectroscopy (FTIR) was employed to study the human epidermis larynx carcinoma cell lines (Hep-2) which were irradiated by different doses of X-ray.The results show that (1) the irradiation of X-ray damages the structure of the CH3 groups of the thymine in DNA,which restrains the reproduction of Hep-2 cells effectively,(2) the 8 Gy dose of X-ray irradiation changes the framework and the relative contents of some proteins,lipids and the nucleic acid molecules intercellular in the greatest degree,and (3) the 8 Gy dose of X-ray irradiation is the best irradiation dose for lowering the degree of the cancerization of Hep-2 cells according to the criteria for the degree of the cancerization reported recently.Meanwhile,the apoptosis of these cells were detected by using flow cytometry (FCM) primarily.It shows that the apoptotic ratio of the Hep-2 cells depends on the irradiation dose to some extent,but is not linearly.And the apoptotic ratio of the 12 Gy dose group is the maximum (20.36%),but the apoptotic ratios of the 2 to 8 Gy dose groups change little.     

Experimental study on SC RF cavities by using China large grain niobium for ILC

Large grain niobium has the potential of simplifying the production sequence and consequently reducing the cost of the superconducting RF cavities for ILC.To investigate the feasibility of fabrication and the possibility to achieve high gradient by large grain cavities,two 1.3 GHz cavities were made of China large grain niobium and a series of vertical tests were carried out following several different surfaces treatment procedures.Two cavities have both reached the high gradient of more than 43 MV/m repeatedly and the maximum accelerating field of 47.9 MV/m has been achieved by China large grain niobium.This paper introduces the features of the fabrication and surface treatments on the large grain cavities and presents the preliminary results of the research.     

Synergistic effects on iodine release in potassium iodide solution by combination of ultrasound and visible light irradiations

Iodine release in potassium iodide solution has been investigated under the irradiations of ultrasound and visible light respectively and simultaneously. We have observed that the amount of iodine liberated under the combined irradiation of ultrasound and visible light is larger than the sum of that under the respective irradiations of ultrasound and visible light, indicating a synergistic effect of ultrasound and visible light irradiations. Based on the investigation of the reaction kinetics of iodine liberated, we have ascribed the synergistic effect to the perfect stirring of the photochemical reactor induced by the applying simultaneous ultrasound. The ideal stirring can result in the homogenization of the primary light effect in the whole reaction medium, which induces the acceleration of the photochemical reaction. On behavior of our knowledge, there are few reports on the investigations of utilizing the combination of ultrasonic energy and light energy to accelerate the reaction yield and rate as well as the kinetics of the reaction.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

A modified voice conversion algorithm using compressed sensing

A voice conversion algorithm,which makes use of the information between continuous frames of speech by compressed sensing,is proposed in this paper.According to the sparsity property of the concatenated vector of several continuous Linear Spectrum Pairs（LSP）in the discrete cosine transformation domain,this paper utilizes compressed sensing to extract the compressed vector from the concatenated LSPs and uses it as the feature vector to train the conversion function.The results of evaluations demonstrate that the performance of this approach can averagely improve 3.21%with the conventional algorithm based on weighted frequency warping when choosing the appropriate numbers of speech frame.The experimental results also illustrate that the performance of voice conversion system can be improved by taking full advantage of the inter-frame information,because those information can make the converted speech remain the more stable acoustic properties which is inherent in inter-frames.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Study on the radiation problem caused by electron beam loss in accelerator tubes

The beam dynamic code PARMELA was used to simulate the transportation process of accelerating electrons in S-band SW linacs with different energies of 2.5, 6 and 20 MeV. The results indicated that in the ideal condition, the percentage of electron beam loss was 50% in accelerator tubes. Also we calculated the spectrum, the location and angular distribution of the lost electrons. Calculation performed by Monte Carlo code MCNP demonstrated that the radiation distribution of lost electrons was nearly uniform along the tube axis, the angular distributions of the radiation dose rates of the three tubes were similar, and the highest leaking dose was at the angle of 160° with respect to the axis. The lower the energy of the accelerator, the higher the radiation relative leakage. For the 2.5 MeV accelerator, the maximum dose rate reached 5% of the main dose and the one on the head of the electron gun was 1%, both of which did not meet the eligible protection requirement for accelerators. We adopted different shielding designs for different accelerators. The simulated result showed that the shielded radiation leaking dose rates fulfilled the requirement.     

Use of Isotope Analysis in Solving Environmental Problems in Power Engineering

Abstract

During hydraulic dumping of ashes at a sludge bed of the power plant at Mělnik (north of Prague), new springs originated which wetted houses and properties at the small village of Podvlci. The sludge bed as well as the village lie at the southwestern margin of the alluvial plain of the Labe (Elbe) River at the foot of a slope built of Cretaceous sedimentary rocks. By analyzing the concentrations of radiocarbon and tritium, it was possible to determine the origin of the water and the ratio of the modern and original groundwater in the new springs in the surroundings of the sludge bed. To substitute the present dump the operation of which should be stopped, establishing of a new one has been proposed within the alluvial plain. By means of stable isotopes and radionuclides, the relations between the groundwater in the Quaternary sediments and in the underlying Middle Turonian confined aquifer were studied, because changes in the hydrogeological regime have to be expected due to the operation of the proposed new sludge bed.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.