CT图像的计算机制全息三维重建

提出用计算机制全息术实现CT图像的三维重建。首先研究了CT图像的三维信息融合,用计算机模拟CT图像的物光波,用菲涅耳计算全息图的方法,把CT图像的二维信息融合成三维信息,获得菲涅耳全息图。然后将计算机制全息与光学全息相结合,记录彩虹全息图。最后用扩展的白光再现,获得逼真无畸变的真正的三维立体图像,充分发挥了计算机制全息与光学全息的优势。在全息图的计算中利用了快速傅里叶算法,大大缩短计算时间。根据不同的观察需要制作了两种不同效果的全息图,并给出了理论分析和实验结果。     

一种新的计算全息标识证件防伪技术

提出了一种新的计算全息标识证件防伪方法.该防伪方法首先通过计算机制作原始认证信息的菲涅耳加密面全息图,并变换成可印刷的全息标识,通过打印或数字印刷将其印制在证件等印刷品中作为防伪标识.原始认证信息的提取过程是加密过程的逆过程.理论分析和仿真实验证明了菲涅耳加密面全息标识方法的有效性和安全性.     

压缩感知重建离轴菲涅耳全息图

针对基于传统数字全息重建算法对待测物体的不同纵向深度截面进行聚焦重构时,聚焦面物体会受到共轭像及背景离焦物体的干扰,本文提出基于压缩感知理论,构建单幅离轴菲涅耳数字全息图层析成像的算法框架。该方法通过自适应空间滤波技术对全息图进行处理,基于压缩感知理论重构不同纵向深度截面图像,并有效抑制背景离焦物体的干扰,最终达到层析成像的目标。计算机数值模拟以及三维待测物体实验结果表明该方法的有效性和可行性。     

医学层析图像的计算全息三维可视化

提出了一种医学层析图像的计算全息三维可视化技术。首先研究了层析图像序列的三维信息融合,将层析图像序列的二维信息融合成三维信息,用计算全息图的方法进行三维信息记录。然后结合空间光调制器的结构特性,对全息系统的空间频率、参物光夹角、取样间隔以及全息再现像的再现区域和视角等进行了讨论和分析,并设置了相关参数,使计算全息系统与电子显示系统相匹配。最后用液晶空间光调制器作为全息图显示载体,用计算机控制全息图的实时输出,用雾屏承载三维空间再现像,建立三维图像光电再现与实时显示系统,实现层析图像序列的三维可视化,给出了理论分析与实验结果。     

低能电子投射全息的计算机模拟和数值重现研究

点源发出的低能量电子波经过样品的散射后,带有物体原子结构信息的散射波(物波)和未被散射的电子波(参考波)在收集平面上相互干涉形成的电子全息图即为低能电子投射全息图.本文在合理的物理模型下,以石墨的晶体结构为试样,通过计算机模拟的方法,首次对低能电子投射全息进行了研究,讨论了一些关键参数对晶体结构电子全息的重现像和分辨率的影响,并且实现了晶体结构三维数值重现,讨论了三维重现的效果.     

基于数字全息和离散余弦变换的数字水印技术

提出了一种基于数字菲涅耳全息和离散余弦变换的数字水印技术.利用全息技术得到原始水印图像的菲涅耳全息图,之后将其嵌入宿主图像离散余弦变换域的中频系数,将水印添加位置和光学系统的几何结构参数作为恢复水印信息的密钥,并且算法属"盲数字水印技术",从而该算法具有较好的安全性和实用性.对算法的测试结果也表明,该算法对噪声,滤波、剪切,旋转、有损压缩等常见的图像处理操作具有较高的稳健性.因此,该算法具有一定的实用价值.     

用于OCT动态聚焦的液晶菲涅尔波带透镜研究

提出了利用液晶菲涅尔波带透镜实现光学相干层析成像(OCT)动态聚焦的方法.根据扭曲相液晶空间光调制器(TN-LCSLM)的光学特性,设计了适用于OCT动态聚焦的菲涅耳波带透镜.利用TN-LCSLM型菲涅耳波带透镜进行了变焦控制实验,焦距实测结果与设计值比较吻合.此外,本文讨论了采用TN-LCSLM型菲涅耳波带透镜实施动态聚焦涉及到的一些问题.     

声直线阵数据的全息处理

声全息是著名的全息处理的一个特殊情况,它的全息图由相干声波产生。一旦把全息信息复制成光全息图以后,物波就能够用相干光来重现。这个方法在水声技术中的特殊问题是把声信息转换成一张适合重现的全息图。为了能够获得所希望的高方位分辨率,必须使用大孔径。因而,接收水听器系统一定要由大量的离散元组成。另一方面,因为接收信号极弱,所以每个水听器后面必须跟着它自己的单独的放大器,以便把它们的输出电压放大到足够高的电平。由于这些原因,水声信号全息接收器变得非常庞大。     

俄歇电子全息的计算机模拟研究和数值重现

原子的芯能级电子吸收能量后被激发 ,经过退激发过程发射出的俄歇电子波在传播过程中被周围的原子散射 ,带有周围原子结构信息的散射波 (物波 )与未被散射的电子波 (参考波 )相干涉形成的衍射图即俄歇电子全息图 ,通过全息图的重现 ,可获得原子级分辨率的三维结构信息。本文在合理的物理模型下 ,以Cu单晶以及高温超导YBCO中的Y原子近邻的一些原子簇为计算实例 ,首次就受激原子周围单层近邻原子散射和多层原子散射产生的俄歇电子全息进行了计算机模拟和数值重现 ,获得了三维晶格结构参量 ,并讨论了不同原子序数的原子在全息图形成及重现中的作用。本工作有助于材料微结构的研究     

激光点阵分形全息防伪印刷

一、全息图复制技术 全息是指应用光的干涉和衍射原理，将物体发出的光波以涉条纹的形式记录下来成为“全息图”，并在一定的条件下再现出和原物逼真的三维衍射像的技术。由于记录了物体光波的振幅和相位信息，因而称为全息术或全息照相。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.