小型反射镜中心支撑技术

所述空间遥感器反射镜的工作温度为18±15℃,要求反射镜在此复杂工况条件下满足设计要求.介绍了反射镜材料和支撑结构材料的选择;对反射镜的支撑方式、轻量化等方面进行了分析讨论;根据反射镜柔性支撑结构的设计原理,采用CAD/CAE工程软件进行了分析及优化,通过有限元法优化设计了一种反射镜中心支撑的柔性结构,在此温度变化范围内,反射镜面形误差变化量PV值小于λ/10、RMS值小于λ/40(A=632.8nm).最后,通过力学环境实验测试反射镜面形变化量和反射镜组件模拟件的动态特性,证明该结构满足设计要求.     

空间遥感器长条形平面镜的背部支撑技术

某空间遥感器的大长宽比长条形平面镜的要求是在尽量减小重量的前提下,在工作温度为20±5℃条件下,反射镜的面形误差变化量(Root Mean Square, RMS)值小于λ/50 (λ=632.8 nm)。介绍了反射镜材料和支撑结构材料的选择;对反射镜的轻量化及支撑方式进行了分析。根据反射镜的外形特点,增加了镜背的局部宽度,并将其设计成了背部三点支撑形式。通过有限元分析,优化并确定了反射镜及其柔性支撑结构。反射镜位移及面形的分析结果满足设计指标要求。最后,通过力学环境试验测试了反射镜组件模拟件的力学特性,证明该结构能满足设计要求。     

单反式光端机反射镜柔性支撑参数化设计与试验

为保证单反式光端机指向捕获跟踪(Pointing, acquisition and tracking, PAT)时反射镜在恶劣空间环境下的面形精度,设计了一种底面开槽的柔性支撑结构。由于柔性支撑结构参数较多,为避免各参数之间严重耦合,采用正交优化方法对柔性支撑结构进行参数优化设计,再利用有限元方法对反射镜组件进行热力学特性分析。仿真分析结果表明,反射镜组件一阶频率为352.61 Hz,在1g重力和10℃温升(温降)共同作用下的最大面形误差RMS为λ/54.79(λ=623.8 nm),能够满足动、静态刚度和热尺寸稳定性要求。使用ZYGO干涉仪在(20±10)℃温度范围内对反射镜面形进行检测,结果表明,反射镜面形PV值优于λ/6,RMS优于λ/43,满足RMS≤λ/40的指标要求。实验结果表明,柔性支撑参数设计可靠,满足使用要求。     

大口径空间红外相机铍铝合金反射镜组件材料选择与设计

针对某空间摆扫相机系统，为了保证空间红外相机获得轻质、可靠的摆扫头部，且各反射镜均具有良好的面形精度及较高的一阶固有频率，对其摆扫部分的结构进行了针对性研究。选择了铍铝合金材料作为Φ750 mm口径主反射镜材料，以钛合金材料的柔性支撑结构支撑，安装在铍铝合金材料的主镜室内。包含次镜组件、次镜支撑和遮光筒，整个摆动部分总质量为17.5 kg。采用有限元方法对反射镜组件在力热耦合状态下进行了仿真分析，结果表明反射镜全口径最大面形误差RMS值为27.04 nm，满足全口径范围内面形误差不低于λ/20(λ=632.8 nm) 的要求。摆动部分一阶谐振频率为122 Hz，为控制系统预留了较大的带宽。实体模型的力学试验结果与有限元分析结果接近，表明满足总体对摆扫部分的设计要求。     

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。     

空间遥感相机大口径反射镜结构优化设计

为满足大口径反射镜在复杂空间环境下对高面形精度和热稳定性的要求,针对某Φ660 mm口径反射镜进行了轻量化研究。提出了一种采用经典理论公式创建反射镜初始结构,结合灵敏度分析和参数优化进行综合设计的方法。首先构建了反射镜参数化模型,采用灵敏度分析研究镜体结构参数对面形变化的影响规律,找到对镜面面形RMS值灵敏度高的结构参数进行优化迭代。相比于传统反射镜结构设计方法,此方法缩小了优化设计空间,节约了计算成本与时间,能够在设计空间内全局寻优,较快收敛于最优值。优化后反射镜在自重载荷工况下镜面面形PV值小于λ/10,RMS值小于λ/40(λ=632.8 nm),镜体质量为13.6 kg,轻量化率达78.4%。镜体组件一阶频率为121 Hz,满足反射镜动态刚度要求,根据优化后的结果建立了反射镜的最佳结构模型,并进行了投产制造。     

空间遥感器反射镜背部支撑结构设计

鉴于空间遥感器反射镜组件需要具有高面形精度、高可靠性和高稳定性支撑的性能,设计了一种应用于天基反射镜的三点背部支撑结构,该支撑结构包括锥套、柔节和修研垫。对三点背部支撑的支撑原理以及工程实现开展了深入研究。对引起三点背部支撑反射镜组件面形误差变化的误差源进行了归纳总结,研究了各个误差源引起面形变化的作用机理,对支撑结构开展相应的设计来缓解各个误差源导致的反射镜的面形精度的变化。首先采用有限元仿真的方法对设计结果开展静、动力学仿真,然后对加工装配完成的反射镜组件开展了试验测试。测试结果表明,在工作状态下采用该三点支撑结构的镜组件的面形误差优于/60（=632.8 nm）,镜体刚体位移小于0.01 mm,镜体转角小于2,质量小于4.5 kg。整个组件具有合理的模态分布,基频是254 Hz,大大高于设计要求值120 Hz。镜组件在正弦振动和随机振动下的最大放大倍率为1.73倍,在正弦振动和随机振动下的最大应力为369 MPa,远低于选用材料的屈服极限。     

离轴三反光学系统主三反射镜支撑结构设计

主三反射镜支撑结构是离轴三反生物成像系统研制过程中的关键技术难点之一,为了减少工作环境下主三镜面形变化,满足支撑系统稳定性要求,利用有限元方法对主三镜组件进行了优化设计。首先,根据光学系统设计要求确定了反射镜及其支撑结构的材料和支撑方式。接着,优化布局了反射镜底部3点和侧面6点支撑位置,设计了轻量化镜室结构。根据优化数学模型设计了圆弧悬臂梁式柔性铰链结构,分析了在重力工况下和温度载荷工况下各参数对镜面面形精度的影响。然后,对反射镜支撑组件进行了静力学和热力学仿真分析,分析结果为重力工况下镜面均方根值RMS为1.529 nm,温度变化4 ℃时镜面均方根值RMS为2.426 nm。最后,采用Zygo干涉仪对支撑作用下的主三反射镜和系统波像差进行检测,实测反射镜镜面RMS值为0.025 λ,系统波像差RMS值为0.102 λ (λ=632.8 nm),基本满足了生物成像系统技术指标（主三镜镜面RMS≤λ/40,系统波像差RMS≤λ/10）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。     

空间相机用大口径圆形主反射镜设计

主镜是空间相机的主要成像部件,其面形误差和位置误差将会决定成像质量。设计了一种孔径为9660 IlllTI的圆形主镜组件。通过对比6点定位原理实现反射镜体的全约束,并经三点在背部支撑主镜,其中每点均为多层柔性结构。合理分配每点支撑的自由度及刚度,同时卸载温度变化时由于材料的线胀系数不同而传递到反射镜上的应力,使反射镜变形均匀。有限元分析结果表明,本文设计的主镜组件的面形误差RMS值达到1/50λ(λ=632.8 nm),一阶模态达到249 Hz,并具有良好的动态刚度。     

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-