长条形反射镜支撑结构设计与分析

为了降低航空光电侦察设备的整体质量,减小反射镜在复杂航空环境下的面形变化,利用有限元方法对某长条形反射镜组件结构进行了优化。首先,计算轻量化反射镜所需的支撑点数量,并对支撑点的位置进行优化。接着,为了解决温度变化时组件材料线胀系数不匹配带来的热变形问题,在支撑结构中引入了柔性铰链,并对柔性铰链参数进行了优化。最后,对反射镜组件进行面形精度分析,得到反射镜RMS为20.3 nm,小于1/30(=632.8 nm);对组件进行模态分析及试验,得到一阶固有频率分别为138 Hz和162 Hz,满足设计指标要求,分析及试验结果表明了该反射镜的支撑结构合理可行。     

大口径SiC轻量化反射镜组件的结构设计

针对某空间相机1.1 m口径反射镜的光机结构设计任务,为降低反射镜的重量,提高其环境适应性,设计了一种重力变形小、抗振性强、热尺寸稳定性高的空间反射镜结构系统。首先,详细分析了反射镜及支撑结构选材依据及应考虑的主要因素。然后,提出一种背部半封闭式扇形轻量化孔的反射镜轻量化结构方案,并利用参数化建模分析的方法对其结构参数进行了优化设计。采用背部三点柔性支撑方式对反射镜进行支撑,通过柔性铰链的柔性来调节由于装配中的过定位和热环境变化导致的反射镜面形精度降低问题。最后,对反射镜组件的力学和热特性分析结果表明,反射镜在X向1 g重力作用下反射镜面形精度PV为62.4 nm,RMS为5.7 nm,在20±4℃环境温度变化范围内面形精度达到PV为61.7 nm,RMS为6.3 nm,反射镜组件基频为150 Hz,能够满足静态刚度、动态刚度和热尺寸稳定性的设计指标要求。     

空间引力波望远镜主反射镜系统的结构设计优化

针对空间引力波望远镜主反射镜系统的结构及支撑组件进行了设计与优化。主反射镜运用了侧面3点支撑对镜体进行约束,并对支撑点的选取与布局进行了研究。反射镜采用能够实现较大弯曲刚度的背部钻孔式半封闭构型,通过有限元计算结合多目标遗传算法对反射镜轻量化结构进行了参数优化,在不降低面形精度的条件下使镜体结构轻量化率达到74%。设计了一种由两个无阻隔串联式柔度单元组合而成的可调节双轴连杆型Bipod柔性铰链结构,其可对反射镜面形误差进行补偿。建立了柔性铰链并联机构作用于反射镜的数学模型,对其进行了基于MATLAB的参数取值分析,并通过有限元方法完成了对参数取值的修正。最后进行了空间热载荷条件下的反射镜面形分析,结果表明反射镜面形误差优于λ/60,满足设计要求。     

空间引力波望远镜主镜组件的结构设计

针对空间引力波望远镜皮米量级的极高光程稳定性需求,对系统中主镜组件进行了优化设计。采用微晶玻璃（Zerodur）作为反射镜材料,支撑结构材料为铟钢（4J36）。首先,通过对反射镜参数的优化,使其在保证面形精度的同时镜体轻量化率达到了72%。然后,设计了一种双轴联杆型Bipod柔性反射镜支撑结构,并采用了侧面三点支撑的形式。以保证有效的支撑刚度及卸载效果为目的,建立了柔性铰链的数学模型,并基于Matlab对其尺寸参数进行了优化。最后,对优化设计后主镜组件进行了模态分析及振动试验,并完成了在轨分析与波前质量计算。结果显示,主镜组件的一阶固有频率为373 Hz,与试验结果的相对误差为3.5%;在轨环境下主镜面形精度达到8.9 nm（RMS）;波前精度为/5（=1 064 nm）。表明该反射镜组件满足设计指标要求。     

大口径空间反射镜组件结构设计与分析

设计了某1.2 m口径的空间光学反射镜结构及其支撑结构系统。首先,合理选取了反射镜及其支撑结构的材料。从反射镜镜坯制作工艺、力学特性、热特性以及反射镜重量等因素考虑,最终选取基于反应烧结SiC材料的背部半开放式扇形轻量化孔的反射镜结构形式,反射镜设计重量为87.6 kg,轻量化率达到79%。其次,确定了在光轴水平状态下进行检测装调的方案,并进行其支撑结构的设计,采用3个双轴柔性铰链从背部对反射镜支撑,使大口径反射镜同时满足静态刚度、动态刚度、强度和热尺寸稳定性的要求。最后,对反射镜进行了组件级有限元分析。结果表明,反射镜在X向重力和4℃均匀温升作用下面形RMS分别为7.8 nm和9.4 nm,反射镜组件一阶固有频率为153 Hz,满足设计指标要求。     

空间光学遥感器长圆形反射镜组件优化设计与分析

为了减轻空间光学遥感器反射镜的镜体质量,并降低反射镜在恶劣空间环境下的面形误差,利用有限元技术对某长圆形反射镜组件进行了优化设计。首先在反射镜进行轻量化后,对其进行支撑点位置优化和结构拓扑优化;其次对柔性支撑进行优化设计,引入了一种新型柔性铰链,解决了因背板热变形导致反射镜径向变形的问题,改善了反射镜面形精度。优化后的反射镜面形RMS 最大值为14.6 nm,小于/30（=632.8 nm）,一阶固有频率大于100 Hz,满足了设计要求,证明了该优化设计方法合理可行。     

大型离轴三反相机主镜组件结构设计与验证

大口径长条形反射镜是大型离轴三反相机的核心部件之一,针对“吉林一号”宽幅01C星中通光口径为1 250 mm×460 mm的主反射镜,系统论述了1.2 m量级大长宽比反射镜组件的结构设计方法,并对所研制的主镜开展了详细的验证。从材料属性和现有工艺出发,镜体材料选择反应烧结碳化硅,采用半封闭式轻量化形式,通过二目标全局优化确定了镜体结构参数的最佳组合,最终镜体设计质量为41.8 kg,面板厚5 mm、最薄加强筋仅厚3 mm。采用经典背部三点支撑方案,优化柔性支撑中的双轴柔性铰链结构参数以兼顾组件基频和热稳定性,并与镜体质心位置进行匹配。提出了主镜组件的装配流程和相应的消应力措施。测试结果表明：主镜在装调重力工况下全口径面形精度均方根值为0.016λ(λ=632.8 nm),翻转180°后主镜全口径面形精度均方根值为0.019λ;实测主镜组件一阶基频为127.8 Hz,经大量级随机振动和高低温循环后,主镜面形精度均方根值基本不变。主镜组件具有良好的动、静力学特性,且面形精度高、稳定性良好,能够满足高性能空间光学系统的使用要求。     

长条形空间反射镜组件轻量化结构设计

针对某700 mm×249 mm长条形空间反射镜组件结构设计要求,对反射镜及其支撑结构进行了详细的光机结构设计。首先,从反射镜材料选择、径厚比、支撑方案及轻量化形式等角度出发,对反射镜进行结构设计。通过理论计算得到长条形反射镜的支撑点数。对支撑点位进行了优化,并探索了支撑孔位对反射镜自重变形的影响规律。其次,为满足反射镜组件的力、热环境适应性要求,设计了一种新型柔性支撑结构,并给出了柔性铰链薄弱环节对反射镜面形精度的影响;对支撑结构安装位置深度进行优化,给出反射镜面形精度关于支撑结构安装位置的变化曲线。然后,对反射镜组件进行了有限元分析,自重和5 ℃温升载荷工况下,反射镜面形精度峰谷（Peak Valley,PV）值和均方根（Root Mean Square,RMS）值最大分别达到58.2 nm和12.3 nm;反射镜组件一阶固有频率为259 Hz,低频正弦扫描振动条件下柔性支撑最大应力响应为138 MPa。最后,进行了动力学试验测试。测试结果表明,反射镜组件一阶固有频率为255 Hz,有限元分析误差为1.7%。分析和试验结果表明,反射镜组件结构设计合理,满足设计指标要求。     

长条形空间反射镜轻量化及其支撑结构设计

为保证空间反射镜在空间应用环境中保持高位置精度和面形精度,实现良好成像,从结构材料的选择、反射镜轻量化设计及支撑结构设计三个方面对某长条形空间反射镜进行了详细的结构设计。提出了一种底面局部开口、三角形加强筋的轻量化形式,反射镜采用背部三点支撑方案,通过合理设计柔性支撑结构参数,使反射镜保证了高刚度和热尺寸稳定性要求。采用有限元法对反射镜系统进行了静、动态特性和热特性分析。分析结果表明:自重及5 ℃均匀温变载荷工况下,反射镜面形精度达到λ/10 PV,λ/50 RMS（λ=632.8 nm）;反射镜组件一阶固有频率230 Hz,具有足够高的动静态刚度和热尺寸稳定性,满足空间应用要求。     

低温反射镜组件结构设计与支撑特性分析

红外光机系统在低温环境工作能够抑制背景噪声提高探测灵敏度,也提高了反射镜组件结构设计难度。低温反射镜支撑结构设计主要问题是由反射镜与连接件热线胀系数不同导致的温度变化工况下的面形变化。对工作于240 K的?450 mm反射镜组件进行结构设计,反射镜材料为SiC,连接件材料为殷钢,采用背部中心单点支撑形式与三角形轻量化形式,并设计柔性连接件提高低温面形表现。对主要设计参数进行优化分析,得到各参数对面形的影响曲线。优化后,反射镜光轴方向重力面形为8.585 nm,径向重力面形3.710 nm,240 K低温面形5.086 nm,一阶模态277 Hz,轻量化率89.4%。     

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.     

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.     

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.     

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.     

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.     

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.