基于微拉曼光谱技术的氧化介孔硅热导率研究

利用基于有效介质理论的介孔硅传热机理,提出一个用于分析氧化介孔硅热导率的理论模型,对影响氧化介孔硅有效热导率的因素进行了理论分析,得出用于计算氧化介孔硅有效热导率的计算公式. 采用双槽电化学腐蚀法制备介孔硅,利用微拉曼光谱技术研究了氧化介孔硅热导率随所制备介孔硅孔隙率的变化规律,比较了经不同温度处理的氧化介孔硅的导热性能差异. 孔隙率为60%,73.4%和78.8%的所制备介孔硅经300℃氧化处理后,其热导率值为8.625W/(m·K),3.846W/(m·K)和1.817W/(m·K);孔隙率为73.4 关键词： 理论模型 氧化介孔硅 微拉曼光谱 有效热导率     

基于微拉曼光谱技术的氧化介孔硅热导率研究

利用基于有效介质理论的介孔硅传热机理，提出一个用于分析氧化介孔硅热导率的理论模型，对影响氧化介孔硅有效热导率的因素进行了理论分析，得出用于计算氧化介孔硅有效热导率的计算公式. 采用双槽电化学腐蚀法制备介孔硅，利用微拉曼光谱技术研究了氧化介孔硅热导率随所制备介孔硅孔隙率的变化规律，比较了经不同温度处理的氧化介孔硅的导热性能差异. 孔隙率为60%，73.4%和78.8%的所制备介孔硅经300℃氧化处理后，其热导率值为8.625W/(m·K)，3.846W/(m·K)和1.817W/(m·K)；孔隙率为73.4     

氧化层对钛吸附和解吸氘动力学影响

为了考察钛表面氧化层的阻氘性能，要进行表面有氧化层的钛吸附和解吸氘实验，从反应动力学的角度，考察吸附和解吸氘反应的快慢，通过计算吸附和解吸氘反应的表观活化能来分析氧化层对吸附和解吸氘特性的影响。     

含冲击波流场干涉图的图像处理方法研究

本文研究了含冲击波流场干涉图的图像处理方法,它包括干涉条纹的快束细化算法,冲击波波阵面的提取算法和时间序列冲击波波阵面的配准算法.根据这些算法,在PC-VISION 100图像处理机上开发了应用软件.实验结果表明,该方法可用于定量计算冲击波的传播速度和压力分布,增加了流场干涉图的用途.     

钛铝合金高温氧化机理电子理论研究

为了从电子层面揭示钛铝合金高温氧化的物理本质,采用递归法与Castep相结合的方式, 计算了原子埋置能、亲和能、结合能等电子结构参数,探索合金氧化机理.研究表明: 氧在钛中有较大固溶度,氧原子可以在钛表面的基体内聚集,逐步向深层扩散. 氧与钛具备较强的亲和力,能形成钛的氧化膜.钛基体中铝原子间具有相互吸引力, 能形成铝的原子团簇.铝原子团簇中的钛原子间相互排斥与铝形成化合物. 铝、钛与氧的亲和能相近,不易发生铝的优先氧化,而是同时生成钛的氧化物和铝的氧化物. Al₂O₃比TiO₂的结合能略低,因而更加稳定,铝在TiO₂中有较大的固溶度, 能替换其中的钛形成更稳定的Al₂O₃氧化物.     

钛的腐蚀与钝化机理电子理论研究

建立了位错塞集引发的裂纹原子集团模型,采用递归法计算了钛的电子结构参量,并研究了氧、氯、钯等元素对钛电子结构的影响.发现氧能降低费米能级附近的态密度,使钛的物理化学活性降低.氧降低钛的原子结合能,与钛原子之间有较大的亲和力,易与钛反应形成氧化膜.Cl在钛中的稳定性及与钛的亲和力均不及氧,很难取代钛表层中的氧,使得钛的氧化膜非常稳定,不会出现过钝化现象.Pd在钛中裂纹处的环境敏感镶嵌能较低,易扩散到裂纹处,且Pd元素使H在裂纹处的环境敏感镶嵌能明显升高,有效减小H向裂纹处的扩散,提高钛的应力腐蚀抵抗力. 关键词： 钛 腐蚀 钝化 电子结构     

氧化孔形状对光子晶体垂直腔面发射激光器模式的影响

用时域有限差分方法对氧化孔限制型外腔式光子晶体垂直腔面发射激光器 (VCSEL) 在小氧化孔下氧化孔形状对激光器模式特性的影响进行了模拟计算. 建立了三维光子晶体面发射激光器光场计算模型, 分析了氧化孔形状变化对器件远场特性与频率特性的影响. 研究发现, 氧化孔形状可影响光子晶体VCSEL的模式特性, 尤其是频谱特性. 从模场分布的角度可解释为菱形氧化孔的对称性与高阶模的不一致. 但随着光子晶体刻蚀深度的增加和氧化孔的增大, 这种影响逐渐减小, 分析解释了其原因. 研究结果为提高光子晶体面发射激光器的性能提供了参考.     

纳米隧道结的制备和特性研究

结合对向靶直流磁控溅射技术、微电子光刻方法和原子力显微镜阳极氧化加工方法制备了实用的纳米钛-钛氧化线-钛隧道结，钛膜的厚度为3.02nm.钛氧化线的宽度为60.5nm，在室温下此隧道结的I-V曲线表现出明显的库仑阻塞效应. 关键词： 原子力显微镜阳极氧化 钛氧化线 隧道结 库仑阻塞效应     

CCD技术在塞曼效应实验中应用的改进

利用CCD图像采集和计算机图像程序处理技术改进了塞曼效应实验系统,对比了测微目镜测量干涉圆环直径、利用手动方法处理实验图像以及利用计算机程序处理实验图像3种方法的实验结果.实验结果表明:利用计算机程序自动处理实验图像的方法能够简化实验并减小实验误差.     

光干涉现象的演示

采用传统方法演示孔(双孔、三孔)和缝(双缝、三缝)的干涉图像,与由传感器采集图像信息后由计算机得出干涉光强分布曲线进行比较,两种方法获得的实验图像符合较好.     

膨体聚四氟乙烯微孔滤膜孔结构的扫描电镜图像解析

由拉伸法制得的膨体聚四氟乙烯(e PTFE)微孔滤膜,其孔结构与其他高分子材质膜截然不同.运用扫描电镜(SEM)图像解析方法描述纤维化的PTFE分子和相互连接的PTFE积聚分子结点,膜的孔性能分别以数字量化的参数: LF、WF、LN、WN、AN表示.测试结果与一般微孔滤膜常用泡压滤速法测定表示孔性能的表观密度和孔隙率有对应关系,说明SEM图像解析可作为表征e PTFE膜孔结构的方法之一.此外,图像解析还可显示原料PTFE分子量和机械操作中的拉伸比对生产的e PTFE膜孔结构的影响.     

Development of porous metal oxide thin films by co-evaporation

This paper focuses on the development of mixed metal oxide thin films and physical characterization of the films. The films were produced by co-evaporation of titanium oxide and tungsten oxide powders. This allowed the development of titanium oxide-tungsten oxide films as analyzed using XPS. Examination in the SEM and AFM showed that the films were nanoporous with the pore size and pore orientation varying as a function of the deposition angle. UV-vis spectra of the films show an increase of transmittance with increasing deposition angle which is attributed to the structure and porosity of the films. Raman analysis indicated that the as-deposited films have broad and weak Raman characteristics, attributed to the nanocrystal nature of the films and the presence of defects, and the peak broadening deceases after annealing the film, as expected.     

SEM investigation of the dependence of magnetic domain structure on the thickness of cobalt monocrystals

The magnetic domain structure of cobalt monocrystal is observed by means of a scanning electron microscope (SEM). It is revealed by the so-called type-I magnetic contrast [1]. The dependence of magnetic domain width on the specimen is thickness is investigated and discussed. Digital image processing (image restoration, enhancement and analysis) is used on the images obtained directly from the SEM. The main reasons for the application of digital image processing are: poor resolution of type-I magnetic contrast due to the diffuseness of the leakage magnetic fields above the specimen surface, and complex character of magnetic domains. The resolution limit of type-I magnetic contrast in cobalt monocrystal is evaluated. Statistical distributions of magnetic domain width are also calculated and presented.     

SEM investigation of the temperature dependence of magnetic domain structure of cobalt monocrystals

The magnetic domain structure of a cobalt monocrystal is observed by means of a scanning electron microscope (SEM). It is revealed by the so-called type-I magnetic contrast [1]. The dependence of the magnetic domain structure on temperature up to about 700 K is investigated and discussed. Digital image processing (image restoration, enhancement and analysis) is used on the images obtained directly from the SEM. The main reasons for the application of digital image processing are: poor resolution of type-I magnetic contrast due to the diffuseness of the leakage magnetic fields above the specimen surface, and the complex character of the magnetic domain structure. Statistical distributions of magnetic domain width are also calculated and presented.     

Pore structure analysis on activated carbon fibers—By cluster and watershed transform method

The microimage of activated carbon fibers (ACFs) obtained from SEM or TEM has low signal to noise ratio (SNR). And the objects in image overlapped together. Image processing methods based on clustering analysis and watershed transform were applied to explore the macropores morphology structure of ACFs. The microimage shows that abundant round-shaped macropores with pore size around 50-200 nm, some of which cluster in the form of ring, distribute on ACF surface. Through clustering analysis, we calculated the surface area of macropores and their distributions. The results showed that the pores characterize within three regions, (1) the pore objects smaller than 30 pixels distributing nearly uniformly; (2) those with pixels between 30 and 165 peaking at lower region and (3) those larger than 165 pixels having fewer numbers and provide the main part of clusters. According to watershed transform segmentation analysis, the overlapped pores in one cluster were separated from each other. The number and other morphology parameters of macropores are calculated automatically and accurately in this paper.     

块状Ta2O5-TiO2复合气凝胶的制备与表征

 以乙醇钽、钛酸丁酯为原料,以乙醇为溶剂,通过溶胶-凝胶法及超临界干燥成功制备了Ta₂O₅-TiO₂复合气凝胶。用场发射扫描电镜（SEM）、透射电镜（TEM）、扫描电镜模式下的电子能谱仪（EDS）以及比表面积吸附仪（BET）对其进行表征。结果表明:该气凝胶是由粒径在nm量级的Ti和Ta的羟基氧化物胶体颗粒堆积而成的低密度、高比表积的多孔网络结构材料,孔径分布主要集中在5~15 nm,比表面积为492.9 m²/g,密度为90 mg/cm³左右。     

Fast Calculation of Computer-Generated Fresnel Hologram Utilizing Distributed Parallel Processing and Array Operation

Fresnel CGH for a three-dimensional (3-D) object is generated by calculating the Fresnel diffraction, but it requires a huge amount of calculation. This is one reason for the difficulty in realizing real-time holography. We propose fast calculation method of computer-generated Fresnel hologram (Fresnel CGH) utilizing distributed parallel processing and array operation. In our method, a projected image with depth information of the 3-D object is prepared to calculate the Fresnel diffraction. The Fresnel diffraction of the projected image is then calculated with depth information by array operation and distributed parallel processing. Parallel processing is realized using JavaSpaces and many standard computers. In our array operation, calculation error in phase distribution on a hologram occurs more than the strict Fresnel diffraction. However, it was confirmed by experiments that the influence of an error can be controlled and ignored. In this paper, our proposed method and some experimental results are shown.     

Effect of fluoride-ion implantation on the biocompatibility of titanium for dental applications

This study stressed on the effect of fluoride-ion implantation upon the biocompatibility of titanium. By using plasma immersion ion implantation technique, fluoride ions were implanted into the smooth surface of pure titanium. The chemical composition and physical structure of the modified surface layers were characterized by X-ray photoelectron spectroscopy (XPS) as well as scanning electron microscope (SEM). At the same time, in vitro co-culture assays were performed to evaluate the biocompatibility of MG-63 cells to the modified titanium. It was confirmed by SEM observations that cell growth on the fluoride-ion-implanted titanium acquired better morphological characters. In addition, the cells on the fluoride-ion-implanted titanium showed the more increasingly and rapidly substrates-attaching capabilities than those on the non-implanted titanium via aridine orange stain assay. Fluoride-ion-implanted titanium could increase the percentages of cells in S phase but without affecting the ratios of cells in G₀/G₁ and G₂/M phases was confirmed by flow cytometry assay. The current results indicated that fluoride-ion implantation could improve the biocompatibility of titanium.     

Research on target photoelectricity track method and improved image processing arithmetic in dynamic targets detection system

To solve the problem that the complexity background affects the dynamic target detection performance, which causes detection performance instability in dynamic target track system, this paper is to study target photoelectricity track method based on revolving image sensor, analyze dynamic targets track principle and track geometry relation on optical image track instrument, put forward the improved Mean Shift target track arithmetic and the improved difference image processing arithmetic to eliminate the background effect; research the positive and negative difference image processing algorithm and image target region extraction, analyze the flow of image processing arithmetic and derivate their calculation method by gathering target image in track detection system. Through experimentation gathering and processing target sequence image, the results show the target track method and processing arithmetic are accurate and feasible.     

层析法计算三维物体全息图的并行加速研究

随着计算空间光调制器的分辨率的尺寸逐渐变大，全息图三维动态显示的计算量也越来越大，使得对全息计算速度提出了新的要求。利用GPU并行计算处理的方式实现全息图的快速层析法计算，该方法利用GPU并行多线程和层析法中的图像二维傅里叶变换的优势对菲涅尔衍射变换算法加速计算；同时通过对GPU底层资源的调用和对CUDA中程序的流处理过程，有效减少中间的延时等待。通过对计算速度对比分析表明:与在CPU上运算相比，计算速度大幅提升，基于GPU并行计算的方法比基于CPU计算的方法速度快10倍左右。