光学低通滤波器技术及其在CCD摄像机中的应用

利用石英晶体的双折射效应设计制成用于CCD摄像机传感器前的光学低通滤波器（OLPF：OpticalLowPassFilter）可以有效地降低或消除离散光电探测器对具有各种不同空间频率目标成像所产生的拍频效应或莫尔条纹混淆现象。OLPF的采用提高了CCD摄像机的成像质量,特别是提高了用CCD摄像机拍摄条状和栅格状目标成像的清晰度,并可消除伪彩色干扰纹的影响。     

二维虚光栅移相莫尔条纹相位提取算法

目前二维干涉图所采用的相位提取算法大多以傅里叶变换法为主,而傅里叶变换法对噪声比较敏感。虚光栅移相莫尔条纹法具有较高的提取精度,而且抗噪性较好。在一维干涉图的基础上,提出了一种适用于二维干涉图相位提取的二维虚光栅移相莫尔条纹法,该方法通过构造一定相移量的二维虚光栅实现相位提取。与傅里叶变换法对比研究的仿真结果表明:对于同一幅二维干涉图,在干涉图不含噪声的情况下,傅里叶变换法与该方法的相对重构误差分别是5.52%和3.46%;在干涉图含噪声的情况下,随着噪声的增加,该方法在抗噪性方面的优势越来越明显。对二维横向剪切干涉仪零位校准装置所采集到的二维干涉图进行处理,实验结果表明,傅里叶变换法和该方法所得到的测量结果均方根值分别为0.0053λ和0.0037λ(λ=632.8 nm)。     

基于莫尔条纹的光纤惯性式振动传感器系统

设计了一种基于莫尔 条纹的光纤惯性式振动传感器,通过光栅对(grating pair)的相对运动产生莫尔条纹实现振 动位移的感知,由4路光纤作 为信号的传输通道将莫尔条纹信息传输至信号处理电路。详细讨论了莫尔条纹与振动信号的 关系,经信号 处理电路以及莫尔条纹细分、方向辨别算法,将莫尔条纹信号转换成振动位移和方向。通过 幅频特性补偿 电路对低频段进行补偿,实现平坦的宽频带频率响应。实验结果表明,传感器的谐振频率为 5.35Hz,通过 补偿后下降至0.05Hz;在0.1～1000Hz频率响应范围内,起伏小于0.011mm。     

基于莫尔条纹的光纤惯性式振动传感器系统

设计了一种基于莫尔条纹的光纤惯性式振动传感器,通过光栅对(grating pair)的相对运动产生莫尔条纹实现振动位移的感知,由4路光纤作为信号的传输通道将莫尔条纹信息传输至信号处理电路。详细讨论了莫尔条纹与振动信号的关系,经信号处理电路以及莫尔条纹细分、方向辨别算法,将莫尔条纹信号转换成振动位移和方向。通过幅频特性补偿电路对低频段进行补偿,实现平坦的宽频带频率响应。实验结果表明,传感器的谐振频率为5.35Hz,通过补偿后下降至0.05Hz;在0.1~1 000Hz频率响应范围内,起伏小于0.011mm。     

莫尔圆的特征参数提取方法

在超精密测量领域中,通过处理同心圆光栅副迭合的莫尔条纹图像可以分离出二自由度的微小误差信息。此前需要对莫尔条纹图像进行预处理,提取出莫尔圆的特征参数。本文讨论了莫尔条纹图像处理的算法问题,介绍了图像预处理算法,包括图像增强、图像滤波、边缘检测、二值处理、轮廓细化、剔除野点等过程,最终用最小二乘法实现对莫尔圆的圆心位置与半径三个特征参数的提取。所采用的一系列方法使单幅含CCD噪声图像的莫尔圆特征参数的定位精度达到亚象素级。     

基于模板匹配的莫尔条纹倾角计算

提出了一种基于模板匹配的亚像素处理方法,可以精确计算出在大口径长焦距测量过程中出现的莫尔条纹的角度。基于泰伯效应和莫尔条纹干涉的长焦距测量方法是一种高精度的焦距测量方法。理论分析表明:这种测量方法的精度很大程度上依赖于莫尔条纹角度的精度。之前是通过迭代算法在亚像素域中寻找莫尔条纹频谱的最大值点来计算莫尔条纹的角度。然而实验过程中得到的莫尔条纹往往会出现不同程度的弯曲和畸形,这会大大影响这种方法的测量精度。从改进测算角度算法这个角度出发,针对傅里叶变换后的频谱图,基于模板匹配的思想,对各种莫尔条纹进行二维正态分布拟合,找出频谱点精确坐标,从而精确测量莫尔条纹角度。理论分析和软件仿真表明:这种方法具有高精度、高稳定等优点,能有效提高长焦距的测量精度。     

自由立体显示器垂直交错狭缝光栅的设计

针对传统的光栅式自由立体显示器设计方法中垂直光栅形成的莫尔条纹明显而斜光栅的对应可视区域较小这一问题.本文提出一种能减轻莫尔条纹的垂直交错光栅设计方法.以一个像素高度的1/2为单位对光栅进行分段,将相邻两段狭缝错开一定距离,减小通过同一狭缝看到两相邻子像素间黑条的比例,提高莫尔条纹中暗部分的亮度,从而减轻莫尔条纹.仿真...     

一种适合低信噪比投影栅的时空二维相移算法

提出了一种适合低信噪比投影栅的时空二维相移算法。首先设计四步相移正弦光栅条纹图,由DLP投影仪投影到待测物体表面,再由CCD相机采集受物体形貌调制的变形条纹图;然后对其中一幅变形条纹图进行傅里叶变换以确定抽样间隔,再对4幅相移条纹图用相移法求得条纹背景和调制幅度后,对每幅变形条纹图做归一化处理;对每幅相移条纹图在空间域进行下采样抽样和灰度插值,构建相移莫尔条纹图,得到多帧时空域相移条纹图;对多帧时空域相移条纹图按时空二维相移法处理求得莫尔相位,再将莫尔相位与抽样点相位叠加求和得到变形条纹图对应的相位数据;最后,以面膜作为样品进行了实验测量,结果表明,经典四步相移法重构的物体形貌出现明显失真,而本文方法能较好恢复物体的三维形貌。     

基于莫尔条纹的自准直测角方法研究

提出了一种基于莫尔条纹的自准直测角方法.该方法将成像式光栅方法、基于莫尔条纹的扭转测量技术、自准直测角技术相结合,利用标尺光栅像和指示光栅形成的光栅副夹角变化所引起的莫尔条纹宽度变化来反映平台棱镜的角度变化,建立了平台棱镜旋转角度、光栅栅线夹角及莫尔条纹宽度之间的关系式.有别于传统莫尔条纹的计数处理,通过图像处理获得了莫尔条纹宽度信息.实验结果表明,该系统接收到的莫尔条纹对比度清晰,满足莫尔条纹图像处理的要求,在±7′范围内,与0.2″自准直仪的比对误差在0.2″以内.     

单光栅数字莫尔位移测量法

提出了一种使用单光栅测量位移的新方法,在该方法中,光栅信号经放大后由图像传感器阵列接收并被传送至计算机,然后通过与其镜像图像叠加的方式得到数字莫尔条纹,最后利用图像传感器像素的空间均匀性对莫尔条纹直接进行细分进而测得位移量。与传统的双光栅莫尔条纹位移测量法相比,该方法完全消除了光栅副层叠间隙,装调更为方便,而且细分成本更低。在阿贝比长仪上对由周期为20 m的光栅和2 0481 536像素的CMOS图像传感器构成的分辨率为0.04 m的测量系统进行测试,结果表明其最大位移误差优于0.18 m。     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-