离子束辅助沉积引发互不固溶系非晶相和亚稳晶相形成

利用离子束辅助沉积技术（IBAD）研究了在互不固溶的Cu-Ta和Cu-Nb系统中获得非晶相和亚稳晶体的可能性,结果表明：r(Cu)为30％时Cu含量的Cu-Ta薄膜得到了非晶相;r(Cu)为25％－35％时Cu-Nb薄膜中随辅助等离子束能量的改变出现了fcc相－非晶相转变;r(Cu）和20％时Cu-Nb薄膜中得到了bcc相,说明IBAD技术可以在互不固溶二元合金系统中制备非晶和亚稳晶相,非晶或亚稳晶的形成是由薄膜沉积过程中辅助离子束的作用引起的。     

溶胶—凝胶方法制备KTa0.65Nb0.35O3薄膜的凝胶化和热处理研究

本文较系统地研究了溶胶－凝胶方法制备ＫＴａ０．６５Ｎｂ０．３５Ｏ３薄膜的凝胶化行为和热处理。用自制的金属醇盐ＫＯＣ２Ｈ５、Ｎｂ（ＯＣ２Ｈ５）５和Ｔａ（ＯＣ２Ｈ５）５为原料，无水乙醇作溶剂，配制均匀的溶液。实验结果表明，溶液浓度、介质或催化剂的使用、匀胶时的环境温度和湿度及单层膜厚等因素凝胶薄膜的形成有较大影响。条件适宜时可得到与衬底附着紧固的均匀透明的凝胶薄膜。随着热处理温度升高，薄膜首先从非晶态     

溅射Co／Cu多层膜的磁性与退火热处理

研究了溅射Ｃｏ／Ｃｕ多层 磁性及退火处理对薄膜磁性的影响。薄膜的易磁化方向平行于膜面，溅射态和退火态的多层膜在膜面内是各向同性的。     

前驱膜中Ga含量对CIGS吸收层性能的影响

采用中频交流磁控溅射方法制备了CuInGa(CIG)前驱膜,并采用固态硒化法进行处理,获得了Cu(In1-xGax)Se2(CIGS)吸收层薄膜.采用扫描电子显微镜和X射线衍射观察和分析了薄膜的成分、组织结构和表面形貌.着重分析了CIG前驱膜中的Ga含量对CIGS吸收层薄膜成分、晶体结构的影响.结果表明,通过调节CIG前驱膜的Ga含量可制备得到Cu/(In+Ga)原子比接近1,且Ga/(In+Ga)比例可调的成分分布均匀的CIGS薄膜.CIGS薄膜由Cu(In1-xGax)Se2固溶体相组成,Ga主要是以替代In的固溶形式存在.在CuIn和CuGa合金靶的功率密度分别为0.24和0.30W/cm2条件下制备的CIG前驱膜经固态硒化处理可获得Ga/(In+Ga)比高达0.2701的CIGS薄膜.     

离子束辅助沉积制备的铁锆多层膜中的相演化

研究了用氩离子束辅助沉积（ＩＢＡＤ）技术制备的铁／锆多层膜中的微结构演化规律。实验中所使用的氩离子能量范围为４ｋｅＶ到１２ｋｅＶ,束流密度为１２μＡ／ｃｍ＾２。实验结果表明,用ＩＢＡＤ技术右在富锆端制备出完全非晶化的薄膜。对于Ｆｅ（０．５４ｎｍ）／Ｚｒ（４．５ｎｍ）多层膜,随Ａｒ离子能量的增加,在薄膜中还观察到晶态－非晶－亚稳ｆｃｃ相－非晶－晶态的结构转变。对于富铁合金膜,ＩＢＡＤ技术仅能制备部分非晶化的薄膜。     

多层膜离子束混合研究亚稳合金形成和理论模型的进展

迄今为止，已经研究了大约９０个二元金属系统的多层膜离子束混合，获得了许多非晶态合金，离子束混合不仅能在负生成热的，通常认为是易玻璃化的系统中合成玻璃，而且在正生成热的非玻璃系统，甚至在正生成热很大的互不固溶系统中也合成了金属玻璃。     

轰击能量对离子束增强沉积Cr—N薄膜微观结构和硬度的影响

采用离子束增强沉积（ＩＢＥＤ）技术，在不同能量氮离子的轴助轰击下制备了Ｃｒ－Ｎ薄膜，通过ＳＥＭ观察、ＸＲＤ分析和显微硬度测定，发现离子轰击能量对Ｃｒ－Ｎ薄膜的表面形貌、相组成和硬度有显著的影响；随着能量的升高，膜表明形貌由岛形颗粒状转变成蜂窝状；一定能量轰击下获得的Ｃｒ２Ｎ和ＣｒＮ混相结合有最高的薄膜硬度；高达１６ｋｅＶ的氮离子轰击可诱发非晶化的出现，并对膜有一定的强化作用。在此基础上探讨了离子轰     

Ba铁氧体溅射薄膜的研究

研究了射频溅射制备Ｂａ铁氧体薄膜的成膜条件对晶化、晶体结构及磁性能的影响。我们的工作表明，为了使射频溅射Ｂａ铁氧体薄膜形成磁铅石结构的晶体，基板温度需高于６００℃，更高的基板温度可获得好的Ｃ轴垂直取向。非晶膜经热处理晶化所需温度要比直接溅射温度高得多。过大、过小的氧气分压不利于垂直膜的生成。使用挡板对最小溅射角限制以后，可在小的基板－靶间距情况下定得Ｃ轴垂直取向的薄膜。     

电子束辐照诱导Cu超微粒子发生反应的HREM研究

用高分辨电子显微镜中的电子束对Ｃｕ超微粒子进行了连续的照射和跟踪观察，结果表明，电子束的辐照，首先使Ｃｕ发生了氧化反应，反应途径：Ｃｕ＋Ｏ２→成分为Ｃｕ和Ｏ的非晶膜→Ｃｕ的晶体氧化物：接着，新生的Ｃｕ的晶体氧化物，在电子束的继续照射下，又发生还原反应，Ｃｕ的氧化物不断地还原为Ｃｕ。在整个还原反应中，伴随着样品局部的多重又氧化还原现象交替出现。     

混合焓对Cu—Ti—Fe—Nb系非晶形成和晶化的影响

利用高能球磨技术研究了混合焓对Ｃｕ－Ｔｉ－Ｆｅ－Ｎｂ系非晶形成和晶化的影响，表明了具有较大负混合焓的体系容易形成非晶相。     

Diffraction of a one-dimensional phase grating in the deep Fresnel field

We analyze theoretically the diffraction of phase gratings in the deep Fresnel field on the basis of the theory of scalar diffraction and Green's theorem and present the general formula for the diffraction intensity of a one-dimensional sinusoidal phase grating. The numerical calculations show that in the deep Fresnel region the diffraction distribution can be described by designating three characteristic regions that are influenced by the parameters of the grating. The microlensing effect of the interface of the phase grating provides the corresponding explanation. Moreover, according to the viewpoint that the diffraction intensity distribution is the result of the interference of the diffraction orders of the grating, we find that the diffraction patterns, depending on the carved depth of the phase grating, are determined by the contributing diffraction orders, their relative power, and the quasi-Talbot effect of the phase grating, which results from the second meeting of the diffraction orders carrying most of the power of the total field, as in the case of the amplitude grating.     

Polarizers and Applications

Three examples of a class of generalized curvilinear diffraction gratings are analysed according to a recently published general theory of diffraction by generalized gratings. The two types of diffraction patterns described by the theory are the Fresnel/Fraunhofer patterns and a new type labelled the ‘image diffraction pattern’ (IDP). Examples of image diffraction patterns are discussed and compared with two methods of predicting the patterns—one method based on optical image processing techniques and the other method based on the solution of the IDP equations by a computer graphics system. The theoretical Fresnel/Fraunhofer and image diffraction patterns are found to be in very good agreement with experiment.     

Aberrations of diffracted wave fields. II. Diffraction gratings

The Rayleigh-Sommerfeld theory is applied to diffraction of a spherical wave by a grating. The grating equation is obtained from the aberration-free diffraction pattern, and its aberrations are shown to be the same as the conventional aberrations obtained by using Fermat's principle. These aberrations are shown to be not associated with the diffraction process. Moreover, it is shown that the irradiance distribution of a certain diffraction order is the Fraunhofer diffraction pattern of the grating aperture as a whole aberrated by the aberration of that order.     

Estimation method for the light extraction efficiency of light-emitting elements with a rigorous grating diffraction theory

The light extraction efficiency of a light-emitting element with microstructured surface is analyzed with a rigorous grating diffraction theory. The grating theory reveals an improvement of extraction efficiency due to diffraction of light by the surface microstructure. The simulation results show that the improvement of extraction efficiency is due mainly to the reflected diffraction rather than to the transmitted diffraction. A part of total-internal-reflection light is diffracted into directions at less than the critical angle. Extraction efficiency is improved by multiple reflection and diffraction of light in a high-refractive-index layer. We propose a simple design method for an efficient surface microstructure from the viewpoint of reflected diffraction.     

Diffraction effects on broadband radiation: formulation for computing total irradiance

I present a formulation for treating diffraction effects on total irradiance in the case of a Planck source; earlier work generally depended on calculating diffraction effects on spectral irradiance followed by summation over spectral components. The formulation is derived and demonstrated for Fraunhofer diffraction by circular apertures, rectangular apertures and slits, and Fresnel diffraction by circular apertures. The prospects for treating other sources and optical systems are also discussed.     

Uniform version of the modified theory of physical optics based boundary diffraction wave theory

The potential function of the modified theory of physical optics based boundary diffraction wave theory is made uniform by using the principles of the uniform theory of diffraction. The line integration of this new function along the edge contour gives the uniform diffracted fields which are finite for the transition regions of the diffraction geometry. The method is applied to the diffraction problem by the edge of a curved surface.     

Formation of anisotropic diffraction gratings in a polymer-dispersed liquid crystal by polarization modulation using a spatial light modulator

Anisotropic diffraction gratings based on a holographic polymer-dispersed liquid crystal (HPDLC) are realized by interferometric exposure using a spatial light modulator (SLM). The SLM is used in the HPDLC grating formation for anisotropic holographic recordings of two-dimensional polarization states for an incident light beam. The diffraction efficiency for P-polarization and the distinctive ratio of diffraction efficiency in P-polarization to that in S-polarization increases with the signal level applied to the SLM. The resulting volume gratings exhibit diffraction efficiency of more than 60% and a distinctive ratio of diffraction over 100. The microscopic origin of the anisotropic property is investigated by an optical polarizing microscope. The novel characteristics of the anisotropic diffraction properties of HPDLC are applied to an image reconstruction technique.     

Diameter estimation of cylinders by the rigorous diffraction model

The Fraunhofer diffraction formula is commonly used for estimating the diameter of thin cylinders by far field diffractometry. However, an experimental systematic overestimation of the value of the cylinder diameter by this diffraction model and other three-dimensional models has been reported when this estimation is compared with those obtained from interferometric techniques. In this work, a rigorous electromagnetic diffraction model is analyzed to determine the cylinder diameter by using the envelope minima of the far field diffraction pattern. The results of this rigorous model are compared with those from the Fraunhofer diffraction formula. The overestimation by the Fraunhofer model is predicted theoretically, presenting a dependence on the wavelength, the polarization state of the incident wave, and the cylinder diameter. The discrepancies are shown to be due to the three-dimensional geometry.     

Ermittlung von Umformeigenspannungen in Tiefziehnäpfen durch Neutronenbeugung

Determination of deformation-induced residual stresses in deep-drawn cups through neutron diffraction Deformation-induced residual stresses in cups of CuZn sheet produced by deep-drawing and similar forming processes were determined by means of neutron diffraction. The experimental procedure is described. Test results were compared with those of X-ray diffraction and mechanical methods whereby only neutron diffraction enables to determine the distribution of residual stresses in sheet thickness direction.     

晶体材料内部残余应力衍射法无损检测的研究进展

目前能够准确、无损地测试材料内部残余应力的手段主要是中子衍射和同步辐射,但这两种测试手段需要核反应堆或高能同步辐射源,投资巨大,只为少数发达国家的少数实验室所拥有,难以应用到实际生产中。短波长X射线衍射仪通过钨靶-K_α特征射线(波长约0.02 nm)以及独特的谱接收方式,达到或接近同步辐射及中子衍射对晶体材料内部晶格应变的无损定点测试,为内部残余应力无损检测的广泛应用开辟了一条新的渠道。介绍了中子衍射和同步辐射对残余应力测试的国内外研究现状,重点展示了短波长X射线衍射仪用于内部应力测试的结果,并就三种测试方法特点进行了对比分析。