三菱PLC在C534J立式车床改造中的应用

为了提高机床加工精度和生产效率,本次设计所要解决的主要问题,是应用PLC技术改造了C534J双柱立式车床的电气控制系统。主要是运用PLC软件进行编程对主轴控制,左右两个刀架控制,横梁升降控制,横梁夹紧控制。通过PLC技术改造,不但可简化控制线路,而且故障率低,可靠性能高,完全可满足该机床的加工要求。     

基于PLC的电气配电柜自动控制系统研究

本文基于PLC实现了配电柜及其连接线路上短路故障的监测、定位和切除。通过监测配电柜的绝缘电阻实现了对配电柜的绝缘智能监控和异常报警,通过故障定位模块实现了对故障位置的快速定位,并通过PLC控制将故障线路及时切除,保证了配电系统的正常运行。     

浅议CA6140型普通车床电气控制系统的PLC改造

本文以CA6140型普通车床为例,将西门子802s base line控制系统应用到CA6140型机床的改造中,通过对控制系统中电源的选用、PLC接口设计、回参考点配置、主轴变频器的选用以及主控电路设计方面进行了阐述。     

可编程控制器(PLC)在红旗变速箱输出轴精加工中的参数设定和编程

现代机械加工中的精确定位经常采用可编程控制器（PLC）与高速计数模块、光电编码器和光栅尺等相配合的方法实现。本文以高速计数模块在一汽红旗轿车的变速箱专门配套的产品输入轴加工工件定位的应用为例，介绍了有关高速计数模块在PLC控制下的编程方法和相关参数设定方式。     

PLC在准确定位控制系统中的应用

为了在一定场合取代高成本的定位控制,实现准确定位控制系统最优的性价比,采用SIEMENS公司S7-200系列PLC作为控制器,控制三相交流异步电动机和步进电机运行以实现准确定位。通过对货物仓储系统中传输带的定位控制,及对直线送料导轨的定位控制的实验,得出了准确定位控制系统设计与实施时的关键技术,并给出了两种实现准确定位的控制方案及PLC程序。这种使用PLC实现的定位方法具有快速、准确、成本低、易于实现的特点,在工业生产中十分实用。     

用可编程控制器对龙门刨床的改造

利用PLC改造老式龙门刨床用的电控部分.根据龙门刨床工艺对控制系统的要求,对电气控制系统进行重新设计.主拖动采用调速范围宽、节能效果显著的变频器,用PLC实现开关量逻辑控制和变频电动机的转速控制.控制系统选用触摸屏作人机界面,实时显示龙门刨床的运行状态和故障信息.给出了电力拖动系统的主回路电路图、PLC的外部接线图.改造后的龙门刨铣床大大提高了机床的性能和加工精度,达到了预期效果.     

基于PLC对专用镗孔机床的电气控制设计研究

本文以专用镗孔机床为机床,首先从专用镗孔机床的工作过程和控制要求进行简要的分析,传统机床的控制系统大都采用继电器-接触器控制,其接线复杂、维修难度大等不足,通过采用PLC控制系统的设计方法,分别对PLC控制系统的硬件、软件部分进行详细的阐述,实践结果表明,采用PLC满足了控制系统的要求,且简化了控制电路,从而取得了良好的效果。     

基于labVIEW的组合机床控制系统研究

本文以三面铣组合机床为研究对象,通过对机床结构和具体工作过程的控制分析,给出一种采用labVIEW进行三面铣组合机床的控制方法。系统通过labVIEW与PLC控制进行通讯,将机床的控制命令以标准通讯规约形式下传至PLC控制器,最终完成机床的控制任务。整个控制系统操作简单,方便,具有极大的可靠性和实用性。     

PLC技术在电气设备自动化控制系统中的应用

文章对电气设备自动化控制系统中PLC技术的主要应用原则进行分析,同时以程序编制、开关控制、机床监管、立体仓库、顺序控制为切入点,阐述电气设备自动化控制系统中PLC技术的具体应用场景。在此基础上,对电气设备自动化控制系统中PLC技术的应用策略与趋势做出分析与展望,旨在实现PLC技术应用优势的最大程度发挥。     

曲轴激光淬火工艺

为实现在将曲轴水平放置绕主轴转动条件下,对单拐或多拐曲轴的主轴和曲柄轴进行激光淬火和激光熔覆,建立了激光作用于曲拐表面形成螺线时的光斑轨迹方程。根据802D数控四轴联动激光淬火通用机床的运动特性,采用圆弧插补方法,以四轴联动方式编程,设计了激光网纹淬火数控程序。在四轴联动激光加工通用机床上实现了曲轴水平放置绕主轴转动对曲柄轴面的网纹进行激光淬火和激光表面熔覆。由于主轴匀速转动,定位不需要配重铁,工作过程稳定,可以一次装夹,不再改变曲轴回转中心,即可完成单拐或多拐曲轴的主轴和曲柄轴的激光淬火和激光熔覆,使802D数控四轴联动激光加工通用机床的功能得到发挥。     

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.