新型分立器件检测系统中大电流板的设计

在分立器件测试系统中采用大电流板构成的回路具有优越的测量性能,根据测试主机对大电流板 的设计要求,自主研制了大电流板,使其具有稳定输出电流3 A和输出电压35 V、稳定交换数字信号的 功能,实际测量结果表明,该系统完全满足了实际生产的需要。

电流变夹层板滑模振动控制

为实现板结构振动控制,基于滑动模态控制思想,设计适用于电流变夹层结构的变刚度控制器,并且推导两类控制律——滑模控制律和简化的开关控制律。先将电流变液处理为可控黏弹性材料,基于Hamilton原理建立电流变夹层板有限元模型。设计滑模控制器时,首先将系统变换到模态空间,然后利用LQR最优控制理论设计控制面函数,设计电流变夹层板的滑模控制器,最后给出两个近似的半主动控制律。对悬臂电流变夹层板进行仿真分析,设计的滑模控制器能显著降低电流变夹层板振动水平,均方根降幅达到88.23%,取得明显优于被动控制的减振效果,体现电流变夹层结构在板结构振动控制应用中的前景。

用板电流特性考察一种新型电除尘器极配

通过测量板电流特性(包括板电流密度分布和伏—安特性)考察鱼骨线、十字线(包括圆管十字线和扁钢十字线)和波形板极配,分析讨论了十字线各结构尺寸对板电流特性的影响规律。在此考察方法下,本文认为扁钢十字线和工业波形板是一种较佳的工业电除尘器极配。

宽间距电除尘器与板电流密度

电除尘器收尘极板上电流密度分布均匀,收尘极上结灰就均匀,提高了收尘极的有效利用率,使除尘效率提高。着重用这一观点解释了宽间距电除尘器效率高的原因,并对多依奇公式中的收尘面积A进行再认识,进而尝试修正多依奇公式中的收尘面积A。

电流变夹层振动控制和拓扑优化研究

为电流变夹层板设计了半主动的变刚度控制算法,并对其进行了夹层结构的拓扑优化。首先,建立了电流变夹层结构的动力学模型,基于开关控制策略发展了适用于ER夹层板的模态控制算法。随后,构造了电流变夹层结构的单阶模态和综合模态的频率变化率为优化目标函数,再采用粒子群优化方法,以这两个函数为目标,对结构进行了拓扑优化,并且得到了一定材料使用率限制下相应的拓扑布置构形。最后,采用变刚度控制的等效阻尼比和多种激励下的时域响应对比两种手段对拓扑优化的结果进行了验证,数值算例证实了该拓扑优化结果以及变刚度控制的有效性。

传导-辐射和磁流体组合对磁化可渗透平板自然对流影响的数值解法

研究粘性、不可压缩、导电流体,在磁化可渗透竖直平板上作自然对流时,数值地分析辐射和磁流体组合的影响.采用两种方法数值地求解非相似的控制方程:1)对所有吸入参数值ξ,采用有限差分法;2)为小数值和大数值的吸入参数值ξ,分别建立起级数的渐近解.用图形和列表形式,给出Prandtl数Pr,磁Prandtl数Pm,磁力参数S,辐射参数Rd,壁面温度θw的变化,对壁面摩擦因数、热交换率和电流密度的影响.最后分析上述物理参数对速度分布、温度分布和磁场横向分量的影响.

电极组合配置在电除尘器提效改造中的应用

电极配置是电除尘器的重要组成部分,通过实验讨论了工业中常用的6种阴极线与C480阳极板配置时的极板表面电流密度大小和分布,分析了不同电极配置形式对电场特性的影响。为改善RS线和BS线结构存在的支撑圆管“电流盲区”现象及BS线内侧芒刺对外侧芒刺电晕的抑制,提出了阴极线结构优化方案;结合三电场中试实验,给出了电除尘器前、后级电场电极配置组合应用的布置形式。电极配置组合方式优化后,电除尘器出口粉尘浓度可降低77.68%。

赛摩拉姆齐给料机控制器XR2105的使用与维护

分析赛摩拉姆齐给料机控制器XR2105在锅炉中应用出现故障的原因,介绍处理意见,并阐明维护工作的重要性,对于日常使用操作具有指导意义。

Improvement of mechanical properties of cold-rolled commercially pure Ti sheet by high density electropulsing

Specimens cut from the cold-rolled commercially pure （CP） Ti sheet were treated by high density electropulsing （the maximum current density 7.22 kA/mm2, pulse period 110 las）. The deformation behaviors of the CP Ti specimens at different states were determined by the uniaxial tensile test. The microstructure morphologies were observed by the optical microscopy. The results show that the electropulsing induced formation of f＇me equal-axial grains and lamellar microstructures, which leads to the strength of the electropulsed CP Ti higher than that of the conventional annealed CP Ti. After electropulsing, the tensile strength and yield strength are increased by 100 MPa. And the electropulsed CP Ti has a good plasticity. The experimental results demonstrate that the electropulsing provides an effective approach to enhance the strength of cold-rolled CP Ti sheet and retain the required high ductility.

电流变夹层板的拓扑优化研究

为了优化电流变夹层板中的变刚度控制效果,对其进行了夹层结构的拓扑优化。首先,基于变刚度控制效果的分析,确立了结构的单阶模态和综合模态频率变化率为优化目标,然后基于粒子群优化算法对结构进行了拓扑优化,并且给出了相应的拓扑构形。最后,采用变刚度控制的等效阻尼比和时域响应对比两种手段对拓扑优化的结果进行了验证,两类验证都表明这些优化的拓扑构形能在较小的材料利用率下,可以取得较好的变刚度控制性能。

Improving in plasticity of orthorhombic Ti_2AlNb-based alloys sheet by high density electropulsing

In order to optimize the ductility of orthorhombic Ti2AlNb-based alloys sheet,Ti22Al27Nb sheet was treated by high density electropulsing（J max =6.80 7.09 kA/mm2,tp =110 μs） under ambient condition.Microstructures were observed by SEM,and the tensile properties were also studied using uniaxial tension tests.The experimental results show that electropulsing can refine the microstructures of Ti22Al27Nb sheets.The specimen with the fine and homogeneous microstructures has good plasticity,and its elongation reaches 19.4%.The mechanism about the effect of electropulsing treatment on the microstructure of Ti22Al27Nb sheets was discussed.It was thought that the increase in nucleation rate during phase transformation and a very short treating time were regarded as the main reasons of producing smaller grains and increase in the plasticity by electropulsing.

Effects of direct current electric field on corrosion behaviour of copper, Cl- ion migration behaviour and dendrites growth under thin electrolyte layer

Effect of direct current electric field （DCEF） on corrosion behaviour of copper printed circuit board （PCB-Cu）, Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using potentiodynamic polarization and scanning electron microscopy （SEM） with energy dispersive spectrometer （EDS）. Results indicate that DCEF decreases the corrosion of PCB-Cu;Cl-ions directionally migrate from the negative pole to the positive pole, and enrich on the surface of the positive pole, which causes serious localized corrosion; dendrites grow on the surface of the negative pole, and the rate and scale of dendrite growth become faster and greater with the increase of external voltage and exposure time, respectively.

旋风脉冲静电除尘器放电极优化实验研究

在旋风脉冲静电除尘器中,分别测试了放电极为十字管芒刺、间隔管芒刺、星形线及圆柱状放电极时的伏安特性、板电流密度和除尘效率,实验结果表明,相同条件下十字管长芒刺具有较大的电流密度,除尘效率也相应较高.对高浓度粉尘适应性好.

铜电解新技术的应用

从永久性不锈钢阴极工艺与传统大极板工艺比较、极板导电系统、控制系统等方面,讨论铜电解精炼技术在设计及实践中的应用。

A Novel ADC Architecture for Digital Voltage Regulator Module Controllers

The design and implementation of a novel ADC architecture called ring-ADC for digital voltage regulator module controllers are presented. Based on the principle of voltage-controlled oscillators＇ transform from voltage to frequency,the A/D conversion of ring-ADC achieves good linearity and precise calibration against process variations compared with the delay-line ADC. A differential pulse counting discriminator also helps decrease the power consumption of the ring-ADC. It is fabricated with a Chartered 0.35μm CMOS process, and the measurement results of the integral and differential nonlinearity performance are 0.92LSB and 1.2LSB respectively. The maximum gain error measured in ten sample chips is ± 3.85%. With sampling rate of 500kHz and when the voltage regulator module （VRM） works in steady state, the ring-ADC＇s average power consumption is 2.56mW. The ring-ADC is verified to meet the requirements for digital VRM controller application.

CFD-DEM simulation of fluid-solid flow of a tapered column separation bed

Research on recycling waste Printed Circuit Boards(PCB) is at the forefront of preventing environmental pollution and finding ways to recycle resources.The Tapered Column Separation Bed(TCSB) is invented aiming at disposing the problem that fine particles of waste printed circuit boards cannot be separated efficiently so as to obtain further insight about the underlying mechanisms and demonstrate the separation feasibility in the tapered column separation bed.In this work,a Computational Fluid Dynamics(CFD) coupled with Discrete Element Method(DEM) model for two-phase flow has been extended to simulate the fluid-solid flow in the tapered column separation bed.Its validity is demonstrated by its successful capturing the key features of particles' flow pattern,velocity,the pressure distribution,the axial position with time and axial force for particles with different densities.Simulation results show that the plastic particles and resin particles become overflow,while copper particles,iron particles and aluminum particles successively become underflow,with a discharge water flow rate of 1 m^3/h,an obliquity of 30°.The simulated results agree reasonably well with the experimental observation.Using this equipment to separate waste PCBs is feasible,theoretically.

各种PCB的技术动向

概述了积层板、元件嵌入基板、散热基板和大电流基板等各种PCB技术动向以及SOC、SIP和大面积电子等。

电能表自动化检定流水线耐压装置的研究与应用

现有技术在进行电能表交流电压的耐压试验时,数据采集不方便,自动化控制程度低,不适合当前自动化流水线使用,本文提出一种适用于电能表自动化检定流水线耐压装置,其数据采集方便,自动化程度高,可以适用于不同的电能表自动化流水线耐压测试。

Influence of arc constriction current frequency on tensile properties and microstructural evolution of tungsten inert gas welded thin sheets of aerospace alloy

The main objective of this investigation is to study the influence of arc constriction current frequency(ACCF)on tensile properties and microstructural evolution of aerospace Alloy 718 sheets(2 mm in thickness)joined by constricted arc TIG(CA-TIG)welding process.One variable at a time approach of design of experiments(DOE)was used,in which ACCF was varied from 4 to 20 kHz at an interval of 5 levels while other parameters were kept constant.The joints welded using ACCF of 4 kHz exhibited superior tensile properties extending joint efficiency up to 99.20%.It is attributed to the grain refinement in fusion zone leading to the evolution of finer,discrete Laves phase in interdendritic areas.An increase of ACCF above 12 kHz caused severe grain growth and evolution of coarser Laves phase in fusion zone.Alloy 718 welds showed more obvious tendency for Nb segregation and Laves phase formation at higher levels of ACCF due to the slower cooling rate.The volume fraction of Laves phase was increased by 62.31%at ACCF of 20 kHz compared to that at 4 kHz,thereby reducing the tensile properties of joints.This is mainly due to the stacking of heat input in weld thermal cycles at increased levels of ACCF.

Process simulation and optimization of flow field in wet electrostatic precipitator

To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.