Al-Pd-Co复杂合金相压痕形变结构的电子显微学研究

本文以Al?Pd?Co复杂合金相ξ′为研究对象,应用FIB技术以及透射电镜,对其室温下的纳米压痕变形微观结构进行了分析表征.结果表明,不同于传统材料的变形,ξ′相压痕下的变形结构以形成的特殊变形带结构为主要特征.这种变形带由高密度缺陷的集合组成,其在形变过程中可协调局域变形,分割晶粒,且其拓展可以选择沿某些晶体学方位优先开动.     

基体取向对激光熔覆修复区域杂晶形成的影响

镍基单晶高温合金叶片的表面缺陷修复是实现其制造及延寿技术的关键,也是材料物理与化学学科的热点研究问题。提出了一种激光熔凝二次旋转基体修复单晶合金的新方法,采用实验与理论模型相结合的方式,以DD6镍基高温合金为研究对象,探究了绕[010]方向旋转45°、再沿[001]方向旋转不同角度ξ时不同晶向区域的分布变化规律。实验结果表明,随着ξ的增大,熔池内一侧单一晶向区域分布增大,同时获得了可使熔池一侧只存在单一晶区的基体取向■(即ξ=45°)。本研究揭示了激光熔凝单晶高温合金过程中改变基体晶向对外延生长组织内部杂晶形成能力的影响机制,并为修复单晶高温合金叶片表面缺陷的激光熔覆修复技术提供了全新的优化思路。     

Mg-Zn-Y合金中W′相与W相的相变研究

Mg?Zn?Y合金中面心立方结构的W′和W相均与二十面体准晶（ IQC）相有密切联系,但W′相的结构还存在争议。综合利用电子衍射分析、能谱分析和像差校正扫描透射电子显微术,确定 W′相的化学成分为Zn60?1 Mg23?9 Y16,具有Cd45 Sm11型结构,内部存在四面体对称的Friauf多面体原子团簇而非二十面体对称团簇,因此W′相不宜称为IQC相的近似相。利用原位加热透射电子显微术研究发现W′相在683 K可转变为W相。二者具有立方－立方取向关系,且W′／W界面具有良好的外延性。热激活作用下原子的扩散和平移引起W相在W′上外延形核长大。     

烧结温度对AuSn焊料薄膜及封装激光器性能的影响

采用不同温度对Au80Sn20共晶合金焊料进行烧结实验,研究了AuSn焊料薄膜在烧结后的形貌、物相组成以及对封装激光器的性能影响等.焊料在烧结后形成ξ相Au5Sn和δ相AuSn两种金属间化合物,随着烧结温度的上升,两相晶粒均明显长大,而ξ相Au5Sn趋向于形成枝晶.较低温度下烧结的焊料表面粗糙度较高,不利于激光器管芯的贴装.高温过烧焊料薄膜的导电导热性能有少许提升,对封装激光器管芯的功率没有明显影响,但焊料薄膜中残余应力较高,使激射波长有所蓝移.该结果将为AuSn焊料的烧结参数优化和硬焊料封装激光器的性能分析提供参考和指导.     

Si和GaAs中的(112)孪晶界

在形变的半导体外延薄膜中经常观察到微孪晶。这种微孪晶的HREM像中往往出现一种三倍于晶格周期性的条纹。本文利用HREM和图像模拟计算技术研究这种条纹的本领。材料有两种:①激光再结晶多晶Si/Si层和②MB EGaAs/Si层。图(1)是Si中的微孪晶的HREM像。图中a和b处是具有敏锐边界的晶界,a处的大白点呈明显的三倍周期性。C处是一个模糊的边界区域。三倍周期条纹的图样特征随着离晶界C的距离而逐渐改变。我们认为这种三倍周期的条纹是两个成孪晶关系的区域重叠而形成的。这种微孪晶片的主晶界是[111]面,而其侧面的晶界应为[112]面。晶界的原子模型如图(2)。按晶界与膜面的取向关系可分成两类,如图(3)。     

激光熔覆反应合成TiC和TiB2的生长机制

利用原子力显微镜(AFM)、扫描电子显微镜(SEM)和透射电镜(TEM)对TC4合金表面NiCrBSiC合金激光熔覆层中反应合成的TiC和TiB2形貌进行了观察.分析了 TiC和TiB2相的生长机制.结果表明,激光熔覆反应合成的TiC相呈等轴树枝品状,并具有非小平面和小平面两种生长界面(当树枝晶尺寸较小时,具有非小平面生长界面,当树枝晶尺寸较大时,具有小平面生长界面),TiB2相呈六棱柱状,通常在TiC树枝晶表面异质形核,并以小平面形式生长,最终形成心部为TiC相外部为TiB2相的特殊复相结构.     

Al-Cu-Mg合金中T相的扫描透射电镜研究

本文利用扫描透射电子显微术,从原子尺度研究Al-Cu-Mg合金中T相(Al20Cu2Mn3)晶体结构的特征。结果表明T相颗粒(010)面存在两种类型孪晶:层状滑移对称型和呈"蛛网"状向外辐射的多重对称型。对孪晶结构分析发现组成孪晶的"双瞳眼睛"状结构单元多数按规则的周期性平行排列,但也有少数区域以混乱的分布方式存在;在某些局部小区域,"双瞳眼睛"状结构单元转变成平行四边形单胞,从而造成晶体结构也发生相应的改变。     

硅离子注入对Ge2Sb2Te5结构和电阻的影响

采用磁控射频溅射法制备了Ge2Sb2Te5薄膜,利用离子注入法研究了硅掺杂对薄膜结构和电阻性能的影响.研究发现,由于硅的掺杂,Ge2Sb2Te5薄膜的结构不仅保留了原有的面心立方低温晶相和六方高温晶相,而且出现了菱形六面体的Sb2Te3晶相;掺杂硅后,Ge2Sb2Te5薄膜的电阻有较大变化,晶态电阻的提高有利于降低非晶化相变过程的操作电流,薄膜电阻-温度稳定性的改善可保证有较宽的操作电流波动范围.     

Ni-Mo-Cr高温合金中μ相非基面缺陷的形成与结构表征研究

本文利用球差校正透射电镜FEI Titan G2在原子尺度下研究了Ni基高温合金中析出μ相内(1(1)2)μ及((1)11)μ面缺陷的结构,对层错的结构特征及形成原因进行了分析.HAADF-STEM成像结果显示,μ相非基面缺陷的出现与μ相的生长特性相关,产生于(001)μ面上不同结构单元相接导致的结构变化.这种形成(0...     

AlCuFeB准晶颗粒增强复合材料中发现的大单胞准晶类似相

在二十面体准晶i-AlCuFeB颗粒增强的Al基复合材料[Al/(AlCuFeB)p]中发现了AlCuFe二十面体准晶的一种新的大单胞晶态近似相.分别用透射电镜和高分辨电镜对此近似相进行了分析,确定其结构为B心正交,其点阵常数是a=1.166 nm,b=1.195 nm及c=3.44 nm.高分辨像还进一步给出了该相在一个伪5次轴晶面内的原子团排列情况.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks