几种实用的泵类／风机控制方案浅析

本文以水泵为对象,介绍了泵类／风机控制（PFC）的工作原理,给出了几种PFC控制系统解决方案,并进行了简单的比较分析;最后提示读者关注先进的多变频器并联泵控制技术。     

逆变器无线并联控制方案的设计与实现

首先对逆变器无线并联的原理作了简单的介绍。其次依据逆变器技术指标设计了一种以dsPIC30F3011芯片为核心控制器的无线并联控制方案,结合系统主电路和相关控制原理,给出了该系统的硬件设计和软件设计。最后以两台逆变器并联为研究对象进行实验验证,实验结果表明该控制方案能够达到技术指标的要求并且能够有效地抑制并联系统产生的环流,使输出功率和负载电流得到均分。     

容错技术在并联机器人控制系统中的应用

本文即是对容错技术在并联机器人控制系统中的应用进行研究,探讨了容错技术的概念,并对并联机器人的各种控制方法进行探讨,最后就容错技术在6-DOF型并联机器人控制系统中的应用进行研究,以期能为相关工作提供参考。     

600kVARPWM整流器的设计与控制

大容量PWM整流器的设计受到单管IGBT电流容量的限制,必须进行并联扩容。本文对几种并联方案进行了讨论,并提出采用交流侧串接电感再进行并联的方案。鉴于在设计LCL滤波器时,其参数的选取直接关系到系统的开关纹波滤除效果,影响系统能否稳定工作,很难做到优化设计,本文引入一种简单实用的计算滤波器参数的方法。使得PWM整流器的纹波和LcL的成本在一个合理的范围。另外本文首次提出了采用AIPhaBeta滤波器进行电网角度获取的新方法,它继承了KaIman滤波器的优点,因此这种方法具有很好的鲁棒性,有效地提高了系统的稳定性和可靠性。在整体的控制方案上采用了双闭环解耦控制的策略．本文分析了电压外环和电流内环的设计。最后通过对600kW整流器主电路的仿真验证了上述技术方案。     

自动浇水控制系统设计与试验

以STC89C52单片机为核心设计的设施园艺自动浇水控制系统,由检测、控制和显示三部分组成。将传感器检测到的温湿度、光照等数据与设定条件进行数据比较,根据比较结果控制水泵开启或关闭,直到参数达到正常标准,由LCD1602显示系统运行状态相关数据。系统有定时和自动两种工作模式,可通过程序设定自动浇水条件,也可通过按键设定浇水时间、次数和时长。系统在proteus软件下进行了仿真,后经实物试验,性能稳定,具有一定应用价值。     

高压变频调速水泵与工频水泵并联在供水系统中的应用

能源浪费一直是制约我国经济发展的一个重要因素,其中供水系统的能源浪费尤为严重。高压水泵因功率大、能耗高的特点,一直是节能领域的重点。由此加装高压变频器就成为企业节能的首选。但高压变频器价格昂贵,占地面积大是其加装改造的弊端。本文通过对高压调速水泵与工频水泵并联使用的研究。以河北钢铁集团邯钢公司能源中心CsP水处理CO3供水系统为例,对8台水泵中的两台进行高压变频改造,使系统成为调速水泵与工频水泵并联运行。改造后,不仅降低了投资,而且节电效果明显。实现了低投入、高节能回报的目的。     

有源电力滤波器电流控制PI校正研究

采用PI校正方法对并联有源电力滤波器电流环进行控制。通过对并联有源电力滤波器的开环幅频特性分析和PI校正分析,得到了并联有源电力滤波器电流环控制的校正参数。通过仿真实验,对有源电力滤波器的补偿精度进行分析,结果证明该校正方法能够取得较好的补偿效果。     

排水自动化系统在焦家金矿的设计应用

矿山井下主排水系统在矿山安全生产中占重要地位,根据水位、峰平谷及其他参数采用PLC控制技术能有效地实现水泵自动开停,实现少人化,无人化,既提高了水泵工作效率,也提高了经济效益。自动化控制系统由PLC根据水仓液位情况、峰谷平时间和涌水量自动控制水泵的启动以及控制启动水泵的台数,自动完成给排水任务。从系统组成、信号处理及程序思路等方面,介绍了排水自动化系统在焦家金矿的设计应用。     

浅谈自动排水系统在数字化矿山中的应用

本文设计了矿井自动排水系统,通过PLC根据时间、水位等参数自动开启、停止水泵的运转,并能实现泵阀的联锁启动,对运行中的各种参数进行实时监控。文中介绍矿井排水系统的重要性,说明了自动排水系统的构成和工作原理,然后介绍整个系统能够实现的功能和特点,自动排水系统达到"无人值守"要求,极大的提高了效益和安全保障。     

熊猫牌可并联逆变器的设计

本文对逆变器并联系统进行了讨论。该系统在电压调节环和电流调节环控制的基础上采用改进型主从并联控制方式，并联系统均流效果好。     

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-