无刷直流电机调速系统模糊神经元PID控制

针对传统PID控制应用于无刷直流电机调速系统存在调节时间长、动态调节特性差及抗干扰能力弱等问题,提出一种基于模糊神经元PID控制的无刷直流电机调速系统设计方法。首先采用神经元控制、比例控制和模糊控制设计了一种可在线调整参数的模糊神经元PID控制器,然后再用其设计无刷直流电机调速系统的转速调节器。仿真结果表明,基于模糊神经元PID控制的无刷直流电机调速系统具有响应速度快、动态和静态调节性能好、自适应能力和抗干扰能力强等优点。     

基于改进WFPSO算法的无刷直流电机模型分析

针对传统的无刷直流电机控制无法在线调整参数、难以精确控制的问题,提出一种基于改进的粒子群优化(PSO)算法的模糊PID控制器设计。通过对粒子群优化算法的参数进行分时段更新,实现模糊PID控制器参数动态全局优化,来确定使用双闭环控制模型的无刷直流电机的最优参数。Matlab仿真结果表明,该研究方法较传统方法可使得转速无超调、减少调节时间,同时启动时转矩脉动较小。     

压电微动平台的改进PID控制

为使压电微动平台具有良好的静动态特性,即响应快,超调量小,无振荡及稳态误差小,采用比例、积分、微分(PID)控制法来对其进行定位控制。将常规PID控制中积分环节的矩形积分改进为梯形积分,以提高压电微动平台的控制精度;采用微分分离法对常规PID控制中的微分环节进行改进,以使压电微动平台在具有良好稳定性的情况下,具有很快的响应速度。实验验证了压电微动平台改进PID控制的有效性,结果表明,压电微动平台对4μm阶跃参考位移的响应时间为0.05s,输出略有超调,但无振荡,且稳态误差几乎为0;在变幅值三角波及任意波形参考输入作用下,压电微动平台的输出可很好地跟踪输入。     

内模PID控制器在无刷直流电机调速系统中的应用

针对无刷直流电机中传统PID控制器参数调节复杂、对环境适应能力较弱等问题,在分析内模控制与经典PID控制的内部对应关系的基础上,综合其优点,设计采用了一种基于内部模型的PID控制器（简称IMC-PID）对无刷直流电机进行调速。在建立对象理论模型的基础上,通过对控制器在线仿真比较表明：针对本设计对象,基于内部模型的PID控制器不论在系统阶跃响应或是扰动跟踪等控制效果上都能到达经典PID控制的要求,同时还降低了参数设计的复杂性和随机性。     

压电微动平台的极点配置PID控制

为提高压电微动平台的位移输出精度,设计极点配置比例、积分、微分(PID)控制器对其进行控制。首先,在对压电执行器进行电学特性、机电特性分析的基础上,建立了压电执行器的数学模型;其次,在对平台进行受力分析、运动分析的基础上,建立了平台的动力学模型;然后,在保持平台极点虚部不变,且将系统闭环阻尼比取为1的情况下,将平台极点沿着平行于实轴的方向平移,设计出平台的PID反馈控制器;最后,实验验证了所设计控制器的有效性。实验结果表明,所设计的控制器可使平台具有较快的响应,在不考虑传感器噪声水平的情况下,平台在控制系统作用下的定位误差基本为0。     

压电式执行器用于超精密进给机构的技术研究

通过对压电陶瓷微位移执行器动态特性问题的研究,设计了一种可微机控制的数字高压信号源作为电压调节器、压电陶瓷作为驱动器的精密微动平台。针对高精度的定位和进给需要,设计了数字闭环控制系统,引入数字比例-积分-微分(PID)模糊控制器以提高系统的动态特性。实验表明,该控制系统简单、可靠、实用,所提出的校正方法对改善压电陶瓷微位移执行器的动态特性有显著效果,现已将其用在磨床进给机构中。     

基于PID神经元网络控制的空间光通信ATP跟踪性能分析

针对空间光通信中跟踪系统的高精度、宽带宽要求,提出了一种基于PID神经元网络(Proportional integral differential neural network-PIDNN)的控制方案.采用MATLAB对所建立的跟踪系统模型进行了仿真分析研究,对采用PIDNN控制器的精跟踪系统的在线训练能力及学习、调整功能进行了仿真验证,同时加入扰动源对精跟踪系统的稳态、动态性能及鲁棒性进行了仿真测试.仿真和测试结果表明:通过PIDNN控制的精跟踪系统具有良好的稳态及动态性能和很强的鲁棒性,系统跟踪精度高且系统带宽较宽.     

基于自适应模糊PID控制的无刷直流电机调速系统

对无刷直流电机的控制技术与调速方法进行了研究,在Matlab7.0/Simulink窗口下,构建了永磁无刷直流电机调速系统仿真模型,设计了自适应模糊PID控制器,对电机的低、中、高速运行状况予以研究,并与常规PID控制器开展对比研究。结果表明:本文所设计的自适应模糊控制系统,不论是动态、还是静态性能,对比常规控制器更加优越,在负载扰动、系统参数的变动等方面,该系统的适应能力较强,控制效果较好。     

面向无人飞行器的模糊闭环控制系统研究

通过对无人飞行器的建模,针对无人飞行器自动定向和自动定高,以及速度在内的一些参数提出了改进控制结构和底层控制方法。针对自动定高、定位等水平面控制提出了串级双闭环控制结构,改进了控制的响应速度和调节精度。针对传统PID控制方法采用粒子群算法(PSO)对PID参数进行优化,与设计的模糊控制器进行对比无人飞行器在底层控制上的优劣。通过仿真对比发现,粒子群优化的PID(PSO-PID)控制效果明显强于普通PID算法,但由于无人飞行器数学模型的不确定性,弱于模糊控制器。仿真实验证明提出的方法具有快速的动态响应,并具有一定的鲁棒性。     

基于钝化微分的压电微动平台PID控制

为避免压电微动平台在工作过程中受到扰动或冲击,采用改进比例、积分、微分(PID)控制器对其进行控制。首先,在平台的PID控制器中引入低通滤波器,以降低微分环节对扰动或冲击的敏感性(即使微分环节对扰动或冲击产生钝化效应),进而设计出了压电微动平台的改进PID控制器;接着,基于所搭建的压电微动平台位移测量系统,实验验证了所设计的钝化微分PID控制器的效果。实验结果表明,在钝化微分PID控制作用下,平台具有较快的响应,达到5μm阶跃目标的响应时间为0.3s,无超调;平台的定位误差显著减小,在跟踪最大值为15.25μm的变幅值三角波时,定位误差中线由无控制时的-0.7～1.2μm减小为-0.1～0.1μm。     

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-