基于FPGA与AD7985的脉冲电源数据采集设计

为了满足精密电镀的控制需求,设计了一种基于FPGA和AD7985的高速高精度的数据采集系统,该数据采集系统可应用于高精度的脉冲电镀电源中,用于采集输出脉冲的电流和电压参数并用于电流调控.首先设计分析了采集系统的主要硬件电路,包括隔离放大电路、电压跟随电路和AD转换电路;然后对AD7985的控制时序进行了研究,给出了控制...     

实验室简易数控直流稳压电源的设计

设计了一套以单片机为核心的智能化直流电源,以AT89S51为主控制器,通过健盘来设置直流电源的输出电流,输出由单片机通过D/A输出实现电流的预置,再通过运算放大器控制晶体管输出一个稳定电压.整个设计以降低产品成本、减小产品体积和提高系统的可靠性作为出发点,系统更加简便、电路结构更加简单,提高了系统稳定性和输出电压值的精...     

高精度数控直流稳压电源的设计与实现

基于单片机AT89S51设计了一种高精度数控直流稳压电源,数控部分采用12位高精度D/A转换器TLV5616控制稳压电路的输出电压;采用12位高精度A/D转换器TLC2543测量输出电压;采用矩阵式键盘作为电压的设定装置;采用LCD1602型液晶显示屏显示设定的电压和实际输出电压;电源以电压串联反馈式稳压电路为基础,并在系统中设计了过流保护电路。     

等百分比调节阀在一阶纯滞后系统的控制策略

根据一阶纯滞后系统的控制模型设计了大林算法的数字控制器,在对等百分比调节阀的放大系数进行线性化处理后,提出便于计算的数字控制器电压输出近似表达式,讨论了数字控制器对系统输出的可调节范围,给出了等百分比调节阀的控制策略.     

基于单片机和FPGA的扫频信号发生器

利用MSP430单片机和Altera FPGA,配合高速数模转换芯片AD768,提出了一种锯齿波扫频信号发生器的设计方法。通过上位机将所需的波形数据信息烧写至单片机,存储在FLASH中,现场可编程门阵列(FPGA)作为系统中的桥梁工具,提供FLASH的读地址和数模转换芯片的控制逻辑。实验结果输出波形正确稳定,符合雷达触发信号的要求。该设计方法简单、灵活,能适应不同信号的输出需求。     

基于注射机健康监测的能量俘获技术研究

结合悬臂梁结构提出一种注射机非线性压电式能量俘获系统。针对能量俘获系统,基于非线性理论和压电方程,建立系统控制方程。采用Matlab软件对系统输出进行模拟仿真实验。模拟实验结果表明:在0.5 g幅值和0～80 Hz频率的加速度扫频激励下,所设计非线性系统的输出电压有效宽度能达到20 Hz,最大幅值能达到50 V,相对于线性系统输出电压最大值39 V和频带范围2 Hz,所设计的系统输出性能有明显提高。     

USB2.0接口传输的FPGA控制与实现

从系统的总体结构、硬件设计和软件设计3个方面阐述了USB2.0接口传输的FPGA控制与实现的设计方法.FPGA作为硬件设计中的主控芯片,完成了对USB接口芯片FT245R的通信控制、SRAM的读写操作等.通过USB驱动连接应用程序和底层硬件,实现了上位机中数据的发送、显示与存储.测试结果表明,FPGA通过USB接口实现...     

基于电容ESR和预测调制的DC-DC变换器双环控制策略研究

针对boost型DC-DC变换器,研究基于输出电容ESR纹波电压的预测调制控制策略.首先提出了无需电流采样,并采用输出电容ESR纹波电压的双环控制系统.其次,为了提升DC-DC变换器系统性能,引入了预测调制策略,可以提高变换器瞬态响应速度,减小由输入电压及负载变化引起的扰动.同时,为避免次谐波振荡,采用谷值后缘预测调制技术.最后,对该变换器进行Simulink仿真,结果表明,采用基于输出电容ESR纹波电压的双环控制,结合谷值后缘预测调制技术,可以稳定变换器输出电压,提升瞬态响应性能.该策略无需电流采样以及谐波补偿等模块,能够有效降低硬件成本.     

基于压电材料的塑料机械状态信号监测研究

对塑料机械进行信号监测,可以及时调控塑料机械的参数,从而保证塑料的加工质量。基于聚偏二氟乙烯(PVDF)压电传感器对塑料机械的压力监测进行了研究,通过压电效应建立了注射机上压电传感器的输出电压模型并进行了数值仿真。研究结果表明:在螺杆匀速运动时,传感器输出电压信号是周期信号,最大幅值和最小幅值分别是10 V和0 V。不同的螺杆速度60、90和120 r/min激励下,传感器的输出电压幅值基本一致,与螺杆旋转一圈所需要的时间相等。不同长度的压电传感器输出电压与螺杆节距有关,当传感器长度小于螺杆节距35 mm时,作用在传感器的螺杆会出现间断,导致传感器输出电压信号出现中断。     

一种测量全电动注塑机的注射压力的方法

全电动注塑机的注射压力、保压压力及储料背压压力是靠伺服电机提供的,而其值的大小要靠压力传感器反馈给控制器并得到调节、控制,选择合适的压力传感器,直接影响注塑机的上述参数是否能符合设计要求。本文给出了一个通过液压注塑机标定熔体压力传感器的输出电压,并使用这个传感器去测量全电动注塑机注射压力值的方法。     

Investigations on vinylene carbonate. IV. Radiation induced graft copolymerization of vinylene carbonate and N-vinyl-N-methylacetamide onto polyethylene films

Graft copolymerization of binary mixtures of vinylene carbonate (VCA) and N-vinyl–N–methylacetamide (VIMA) onto low density polyethylene (LDPE) films was studied by the mutual γ-irradiation technique. Sufficient amounts of functionally active VCA groups could be grafted onto the surface and the hydrophilicity of the surface was also improved. The grafting of VCA onto polyethylene films in the binary solutions was found to be promoted by the presence of VIMA, thus showing a positive synergism. The VCA content in the graft copolymers was always higher than in the copolymers obtained by homogeneous copolymerization using the same monomer feed composition. The monomer reactivity ratios, as well as a preferential partitioning of the monomers surrounding the polymeric substrate, were considered to explain the grafting reactions in the binary systems.     

Photosensitive poly(vinylene carbonate)s based on reaction development patterning with dilute aqueous alkaline solution

We examined positive‐tone pattern formation based on reaction development patterning (RDP) using hydrolysis of carbonate groups on the side chains of vinyl polymers. Homopolymers and copolymers with carbonate groups were prepared by radical polymerization using vinylene carbonate (VCA) as a monomer. Application of RDP to the VCA homopolymer resulted in unclear positive‐tone pattern because the high reactivity of the carbonate group led to insufficient difference in solubility between the exposed and unexposed areas. When we applied RDP using 5.0 wt% NaOH_aq as developer to the copolymers between VCA and vinyl acetate (P(VCA–VAc)s), clear positive‐tone patterns were successfully obtained. The effect of the ratio of carbonate groups in the copolymers on the development property of the RDP process was examined, and the use of a copolymer in which the ratio between VCA and VAc was 1:0.6 was found to yield positive‐tone pattern with the highest contrast. Pattern formation using more dilute developer (1.0 wt% NaOH_aq) was also achieved. Though conventional photosensitive polymers are required to have acidic or protected acidic groups for alkaline development, we succeeded in addition of photosensitivity to P(VCA–VAc)s, which do not have such functional groups, by using dilute aqueous alkaline solutions as developers. © 2015 Society of Chemical Industry     

Standardization of a newly designed vibrating capillary apparatus for the preparation of microcapsules

Vibrating capillary apparatus (VCA) was designed and constructed for the preparation of sulphamethoxazole (SMZ) microcapsules using gelatin as a coating polymer. The microcapsules were characterized by physico-chemical methods. The apparent diffusion coefficient D_a and diffusion rate constant K_BL of the drug were measured at pH of 1.2 and 7.2. Better controlled release products were obtained in the VCA.     

防喘振控制技术在小型离心压缩机上的应用实践

采用杭州和利时自动化有限公司的T810S控制系统对小型离心式压缩机的控制系统进行技术改造,氮气压缩机机组在正常生产阶段,入口导流叶片和防喘振放空阀门始终投入全自动控制方式,确保机组安全运行的同时,最大程度地提高了生产工艺参数的调节品质、避免放空造成的浪费。     

Hydrogen Adsorption on Ordered and Disordered Pt-Ni Alloys

Topics in Catalysis - The bulk properties and chemical reactivity of disordered Pt-Ni alloys in the A1 (fcc) structure are investigated using different methods: Virtual Crystal Approximation (VCA),...     

Evaluation of use of the optional unit QA-810V for the determination of five-part leukocyte differentials

The newly developed QA-810V is an optional unit for the determination of five-part white blood cell differentials. It can be used together with the same manufacturer's haematology analyser which has been used in relatively small-sized laboratories. The present study evaluates the basic performance of the QA-810V and the MEK-8118 haematology analyser using routinely obtained blood specimens treated with ethylenedioaminetetraacetic acid-2K. In this evaluation, reproducibility was good and little carryover was found. Accurate measurements were possible for up to 24h of storage. Storage at 4 ( degrees )C yielded more stable measurements of complete blood counts and five-part differentials than storage at room temperature. A good correlation between findings with the MEK-8118 haematology analyser and those with the SE-9000 haematology analyser was found for complete blood counts. The leukocyte differential obtained with the QA-810V correlated well with eye counts, with r > 0.9 for percentages of neutrophils, lymphocytes and eosinophils. Scattergrams obtained with the QA-810V reflected the presence of abnormal cells. The performance of the QA-810V was excellent and it can improve the quality of testing in clinical laboratories.     

新型高分子助剂在自动洗碗机清洁剂的应用

研究了一种新型高分子助剂Noverite~(TM) AD810的钙离子螯合能力、玻璃杯浸泡老化实验及在含氯或含酶自动洗碗凝胶及自动洗碗粉中的应用性能。实验结果表明,Noverite~(TM) AD810有着良好的钙离子螯合能力,并且不会引起有花纹玻璃杯颜色变化。在所测试的多种自动洗碗机清洁剂产品中,含Noverite~(TM) AD810配方均显示出良好的抗成膜、抗成斑点及阻止碳酸钙沉积在器皿表面性能。     

810酯在汽车密封条用PVC软质粒料中的应用

研究了将 810酯和DOP按各种比例混合作主增塑剂 ,用于制作汽车密封条用PVC软质粒料 ;试验了810酯用量比对材料硬度、拉伸强度、断裂伸长率、回弹性、热失重、熔体流动速率的影响。实验结果表明 ,810酯完全可以替代DOP作为主增塑剂使用 ,它的增塑效率与DOP相当。用它作增塑剂制作的PVC材料 ,其耐寒性、回弹性、耐挥发性均优于用DOP制作的材料 ;虽然材料的拉伸强度、断裂伸长率略有下降 ,但均能达到和超过汽车密封条用PVC软质粒料质量标准。     

New supports for enzyme immobilization based on copolymers of vinylene carbonate and β‐hydroxyethylene acrylate

Vinylene carbonate (VCA), β‐hydroxyethylene acrylate, and N,N′‐methylene bisacrylamide were dissolved in water, and the aqueous solutions were copolymerized via reverse‐phase suspension copolymerization in paraffin oil. A series of hydrophilic and beaded supports containing reactive cyclic carbonate groups for enzyme immobilization were obtained. The supports were examined by coupling with trypsin, and the results showed that the amount of enzymes coupled to the supports and the specific activity of the immobilized trypsin were related to the content of VCA structure units and the reaction time. Meanwhile, the optimal pH and temperature, as well as the Michaelis–Menten constant K_m, for both native and immobilized trypsin were measured. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 94–102, 2002     

燃烧器头部组件用新型高温耐磨材料的研究

本文介绍了中材装备集团有限公司热工分公司为提高燃烧器使用寿命而研发的一种碳化物强化奥氏体耐热钢T810N,通过添加W、V、Ti、Nb等元素来形成高硬度、高熔点的碳化物,从而提高材质的高温耐磨性能。试验研究表明,T810N在高温抗氧化性能、室温及高温拉伸性能、高温耐磨性能方面较ZG40Cr28Ni16有显著提高,能够满足提高燃烧器头部组件使用寿命的要求。