超声马达模糊控制系统的理论研究

设计了一种新颖的线性双向式超声马达，介绍了典型的超声马达的驱动控制方法，提出了基于模糊控制理论的超声马达的过程调节方法，分析了模糊控制器的结构和原理，给出了模糊控制器的设计方法，最后指出了超声马达模糊控制过程调节系统的发展趋势。     

行波型超声马达的数学模型

简介了超声马达的结构和工作原理,针对超声马达结构特殊、机理复杂的特点,从控制的角度出发,采用系统辨识的方法,建立了行波型超声马达的三种数学模型,实验结果证实了模型的有效性。     

超声马达的应用和发展动向

在简明阐述超声马达基本原理及性能特点的基础上,重点介绍了目前超声马达的应用情况,并展望了超声马达的研究和发展方向。     

真空度对环形行波超声马达驱动特性的影响

超声马达是一种适合于真空环境中工作的理想驱动器,但其在真空下的特性研究较少。利用真空试验机和超声马达特性模拟实验台,分别在常压、低真空和高真空下测试了无磁型和普通型环形行波超声马达的转速和转矩特性。结果表明,两台超声马达的转速和转矩均随环境压强减小而减小;在真空下,普通型超声马达的负载特性较常态下差,无磁型超声马达负载特性受真空度影响较小,且优于普通型超声马达的负载特性。运用声悬浮和摩擦学理论初步分析了产生此现象的原因。     

定量马达闭式调速液压系统的动态仿真

通过对变量泵定量马达容积调速系统的数学建模和利用MATLAB进行动态仿真,直观地分析了系统的动态特性以及影响特性的因素和影响规律,仿真结果与系统的理论分析相符合。     

直线超声马达研究进展

简述了近十年来直线超声马达的研究进展,分析了超声马达在结构设计和摩擦驱动等方面的关键问题。分析表明,开发新型原理的超声马达方兴未艾,但接触型马达为目前直线马达的主要发展方向。本体结构简化、驱动性能增强、工作效率及稳定性提高,是超声马达结构设计时应考虑的目标和任务。但接触型直线马达正常工作过程就是定/动子间的高频冲击磨损过程,定动子间摩擦学设计至关重要。另外,装配预紧力、接触间隙和磨损过程等引起的非线性问题,在马达设计制造和使用维护中应给予关注。最后,探讨了马达使用性能及运行寿命的影响因素,并总结了直线超声马达工作过程中的能量损失缘由和噪声产生机理。     

基于阶跃响应的环形行波式超声马达特性测量

从超声马达转子的运动方程入手，在假定转子受定常阻尼的条件下，求解出阶跃响应，并由此推导出超声马达的输出特性。利用阶跃响应和传统的悬挂砝码的方法分别测量了环形行波式超声马达的负载特性，实验结果表明，两种方法之间的测量误差优于１０％。     

纵扭复合型超声马达共振频率的研究

对夹心式纵扭复合型超声马达的共振频率进行了研究.研究分析表明,负载因子同超声马达的共振频率有密切的关系,负载因子越大,超声马达工作时的共振频率下降的越多.因此,超声马达工程设计中应尽量选用声阻抗大的材料作为超声马达定子以确保其共振频率最小程度的受负载的影响.纵扭复合型超声马达共振频率的理论值与测试值基本符合.     

环形行波超声马达驱动电路的研究和设计

在介绍超声马达运行机理的基础上，分析了环形行波超声马达对驱动电路的要求，用驱动电路解决了超声马达中压电振子的极化问题，设计出了一种新颖的具有频率自动跟踪功能的行波超声马达驱动电路，分析了驱动电路的工作条件，得到了超声马达转速频率关系曲线。     

复合棒型超声马达固有频率的设计

本文给出了一种分析复合棒型超声马达固有频率的简便方法，并可在此基础上分析定子纵振动和扭转振动的位移分布。与有限元法和机电等效电路图法相比，此方法物理概念清晰，便于工程应用。为进一步研究超声马达提供了一个理论工具。     

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-