为了解决纳米多孔材料特征尺寸无损表征的问题,本文提出一种基于改进的过渡流态流导理论的气体渗透测量方法,通过搭建动态差压瞬态测试系统,对过渡流态下气体通过多孔介质材料的流导进行实时测量,从而得到流导随气体平均自由程的变化关系,并以此推出多孔介质材料的平均孔径.实验对两组不同面积大小的多孔阳极氧化铝(AAO)进行了测试,其测试结果与SEM图像分析结果相吻合,相对误差在8％以内.该测试方法无需提前知道待测材料的孔隙率,且具有样品无损、结果准确、大面积测量的优点,拓展了气体渗透测量技术的测试范围.

基于降压型结构,设计了一种高精度的恒流LED驱动电路.在滞环控制模式的基础上,采用一种新型的自适应关断时间控制环路替代谷值检测反馈环路,间接地实现了对电感电流谷值的精确控制,避免了对谷值直接采样所带来的误差,提升了系统的恒流精度.控制环路采用低边采样方式,降低了采样电阻上的损耗,提升了系统的转换效率.该LED驱动电路基于TSMC 0.18μm 70 V BCD工艺进行了仿真与设计.结果 表明,在20～ 125 mA负载电流范围内,最大恒流误差不超过0.8％.在20～100 V输出电压范围内,平均电流变化率小于1％.

针对当前空调散热器工艺生产中常用除油工艺的局限性,本文提出了节能环保的真空干燥除油法,并就真空干燥除油箱体内温度场进行研究,利用FLUENT中DO模型仿真得到:在热源加热稳定的真空箱体内,分两层间隔布置的散热翅片的适宜摆放位置在箱体下半区域,该区域内温差较小,温差在7℃左右,其次对有效加热区范围进行了相关探讨,然后利用控制变量法建立起了热源总功率P与箱体体积V的理论模型,对除油箱设计具有一定的理论指导意义.

介绍了一种应用于高速逐次逼近型模数转换器的新型高能效电容开关方案.基于2bit/cycle结构,采用两个分裂电容阵列作为数模转换器.通过单边充电操作,在减小电容阵列动态功耗和总面积的同时,提高了电容的建立速度.在最后一个量化周期中,只在电容阵列的单边引入共模电压基准,并只用一个比较器参与量化,在获得更高精度的同时,进一步降低了电容阵列的动态功耗.相比传统1bit/cycle电容开关方案,该新型电容开关方案在提升系统量化速度约2倍的同时,降低了电容阵列平均功耗83％,减小了电容总面积50％.相比其他2bit/cycle开关方案,在精度、电容总面积和功耗方面均有不同程度的改善.

真空除油干燥法作为一种极具发展前景的新兴除油方式,比常规除油方法效率高且环保.文章针对空调散热器除油干燥系统的温度场进行研究,利用FLUENT模拟出真空干燥室合适的热源布局方式,以优化除油腔室内的温度场分布,进一步提高除油效率.

变螺距转子计算得到的理论允许最小间隙,利用SolidWorks软件的布尔运算功能,对转子的每个面单独做切削处理,建立了含有实际间隙的变螺距转子的三维模型.在此基础上,在变螺距转子的进、排气端面内部与转子的外圆端面去重处理,消除转子高速运转中的动不平衡效应,得到了可用于加工的实际变螺距转子.对导程小导致齿厚较薄的转子,在Solid-Works软件中将其凹面与齿根面相交处的小圆角增大至设备可加工的数值并保证其间隙合理,不会卡死.

为了了解脉冲作用时间对选择性激光熔化的影响,分析了脉冲作用时间、激光输出功率以及脉冲峰值功率之间的关系.通过单熔点、单熔道以及工件实验,研究了脉冲作用时间影响单熔道薄壁件和实验工件成形质量的机制.结果 表明:当输入能量相同时,脉冲作用时间与单熔点、单熔道的宽度正相关;脉冲作用时间越长,在熔道附近形成的热影响区域越大;减小脉冲作用时间,有利于提高薄壁工件的表面质量和减少成形实体工件时产生的热积累.

To meet the requirements of small area, high precision and low power consumption of AMOLED driver chip, a high performance output buffer with DAC function is designed. This buffer adopts rail to rail input stage and Class AB output stage to adapt to a large input and output voltage range, and uses Cascode Miller compensation to reduce the size of the compensation capacitor. Its tail current source is programmable to implement 4 bit DAC function interpolation, saving overall power consumption and chip area. Under the UMC80 nm CMOS process, the simulation results show that in the input voltage range of 0.2 similar to 6.3 V, the DC gain of the buffer is greater than 70 dB, the phase margin is greater than 60 degrees, the quiescent current can be as low as 0.5 mu A, and the settling time as low as 1.49 mu s. With a typical medium voltage of 3.3 V, the DC gain can reach 129 dB, the phase margin is 75 degrees, the gain bandwidth is 9.4 MHz, and the quiescent current is 1.3 mu A. After 4 bit interpolation of the 60 mV input voltage, the output error is less than 0.255 mV. The designed buffer has high accuracy, fast settling time, and low power consumption. The output buffer realizes the role of the second-stage DAC, which meets the application requirements of AMOLED source driving.

在选择性激光熔化(selective laser melting,SLM)加工过程中,制件同一层加工区域的面积可能不相等,若采用相同激光功率和扫描速度持续加工,则局部区域的热积累效应会越来越严重,最终会降低制件成型质量.针对此问题,文章介绍了一种添加工艺参数的CLI+文件格式.通过判断加工区域面积,据此添加不同激光功率和扫描速度,从而实现分区域控制的选择性激光熔化工艺.实验验证了该方法能够有效地提高制件的成型质量.

本项目拟采用超声波干燥辅助热风、离心干燥的工作方式,通过合理的机械机构,来设计出一款可以全自动高效完成雨伞干燥的沥干装置.该装置具有干燥效率高,过程自动化程度高的特点,快速便捷的干燥流程可以满足商场、图书馆、车站等人流量大的场合需求.

秸秆粉碎机是实现生物质能源优质开发利用的基础设备,其抑尘结构的设计优化则是实现粉碎机安全环保运行的关键.本研究设计了一种变径式粉碎机,通过转子刀片高速旋转与变径结构产生低真空区域,在粉碎机进料口产生向内压差,增加粉碎机内颗粒逃逸阻力,实现抑尘作用.首先,采用理论分析得到了变径式粉碎机内颗粒逃逸阻力压差值;其次,采用MRF方法和DPM模型对粉碎机内气固两相流进行CFD模拟,结果表明变径式粉碎机可降低进料口逃逸粒子数约30％,抑尘效果显著;而后,本研究对变径式粉碎机的工作转速在(500～6000)r/min、颗粒尺寸在(1～5000)μm、变径比在1～1.2范围内参数进行优化分析,获得抑尘率可达57％的变径式粉碎机结构及工作参数,为秸秆粉碎机抑尘结构设计及安全环保运行提供理论基础.

文章基于热重分析对高水分毛竹废弃物的非等温干燥特性进行了研究,探讨了含水率和升温速率对毛竹废弃物干燥过程的影响.研究结果表明:含水率越高,升温速率越小,干燥所需的时间越长.采用迭代法对水分比以及4种非等温干燥模型进行非线性回归拟合分析,通过综合分析评价参数和残差分布可知,Henderson模型具有较好的拟合效果,是描述毛竹废弃物内部水分迁移规律的最优模型,并得到毛竹废弃物干燥所需的表观活化能为34.35～41.75 kJ/mol.

针对电容式汽车油液传感器的研究现状,介绍了一种免介电常数标定电容式油液传感器的设计方案.主要设计了一个含有两块相同三角形极板的电容器,利用特殊的结构设计和两块极板所测的电容值微分相除来抵消介电常数的数学方法,得到精确油液高度,不再需要对油液的介电常数进行标定以消除其对电容测量的影响,并利用模型实验的方法验证其测量结果的连续性和准确性.随后在能连续测量油液高度的基础上,通过单片机及GSM模块控制实现油液品质异常报警及油量快速异常下降时的智能化监控报警,使之能够有效应对油液监控不稳定以及因油品不合格对车辆自身带来损伤等情况,并避免偷油漏油少加油等现象的发生,帮助实现油液的精确监控和实时反馈.

The tetrahedral amorphous carbon ( ta-C) coatings were synthesized by multi arc ion plating in the reactor with a 90o-duct magnetic filter.The influence of the growth conditions,including the magnetic field,duct bi-as,baffle-aperture and arc-current, on the ion transport and macro-particle removal was investigated.The results show that the synthesis conditions all had a major impact.To be specific,as themagnetic field increased,the ion cur-rent and macro-particle density increased;in a mild magnetic field,an optimizedbias of +15 V enhanced the ion transmission efficiency by~70%;and as the baffle-aperture decreased,the macro-particle density significantly de-creased,accompanied by a deposition-rate reduction.Though little affecting the ion transmission efficiency,a de-crease of the arc-current markedly reduced the macro-particle emission.We suggest that the results be of some tech-nological interest in industrial production of ta-C coatings.

Surface crack is a common problem of asphalt pavement ,and it can be efficiently repaired by polymer grouting .In this paper ,the three‐dimensional 20‐node isoparametric elements model was built by introducing singular element using finite element software ABAQUS in order to conduct the mechanical analysis of asphalt pavement before and after repairing .The tensile stress of asphalt layer under the conditions of offset load ,thermo‐mechanical coupling ,etc was calculated .The vehicle dy‐namic load was simulated by user subroutine to analyze the stress intensity factor of crack tip after re‐pairing .The results show that the cracks of asphalt layer can be efficiently repaired by polymer grou‐ting ,and the tensile stress of asphalt layer and the stress intensity factor of subbase course can be re‐duced ,w hich can avoid damage of asphalt pavement under normal load so as to prolong its service life .

The paper focuses on the decentralized control of vibration of tall buildings under earthquakes and studies the substructure division tactics of tall buildings by introducing information-sharing overlapping decentralized control strategy.Based on optimal weight matrix of Linear Quadratic Regulator Optimal Control(LQR)and optimal output evaluation matrix of H∞ robust control,the paper furthermore analyzes and evaluates the control effect on tall buildings with different substructure divisions.A typical 20-floor seismically excited building is used to analyze the performance of the control strategy.The results indicate that the two overlapping decentralized control tragedies proposed here can guide the substructure division of tall buildings under overlapping decentralized control.The strategies can guarantee a satisfactory control effect and keep the control force within a reasonable range.

研究了聚合电场波形对常黑模式聚合物稳定胆甾相液晶（PSCT）网络形貌和光电性能的影响。采用紫外光聚合诱导相分离法（PIPS）制备聚合物稳定胆甾相液晶,通过使用3种不同的聚合电场波形（方波、正弦波和三角波）来控制聚合物网络的形貌,改善PSCT的光电性能。聚合电场为方波时,聚合物网络最为疏松,阈值饱和电压最小,响应时间最长,迟滞宽度最大;而聚合电场为三角波时,聚合物网络最为致密,阈值饱和电压最大,响应时间最短,迟滞宽度最小。

为了调节聚合物网络与液晶分子之间的相互作用,从而改善聚合物稳定胆甾相液晶（PSCLC）的光电性能,本文采用紫外光聚合诱导相分离法（PIPS）制备了聚合物稳定胆甾相液晶,通过控制2种单体RM257与BAB6的比例来改善器件性能。随着RM257含量的减少,聚合物网络由取向排列的纤维状结构向疏松不规整的交联状结构转变,形成的聚合物网络对液晶分子的锚定作用减弱,聚合物稳定胆甾相液晶的饱和电压降低,关闭时间增大。当RM257与BAB6质量比为1∶4时,聚合物稳定胆甾相液晶器件具有较好的对比度。

Top-contact organic thin-film transistors array was prepared by slectively dewetting of 6,13-Bis(triisopropylsilylethynyl) pentacene(TIPS-Pentacene) solution.The optical microscope images showed that the morphology of TIPS-pentacene crystal was influenced by the rotation speed.The TIPS-pentacene thin-films prepared at 1 000~2 000 r/min had good connectivity and large crystal domains.As the rotation speed increased to 3 000 r/min,the patterned film became incomplete and the crystal domain size reduced.The output and transfer curve,on/off current ratio,threshold voltage and field-effect mobility of the device were obtained by electric measurements.The TIPS-pentacene OTFTs prepared at 1 000 r/min had a maximum field-effect mobility of up to 5.16×10-2 cm·V-1·s-1 and an on/off current ratio of 8×103.

High-performance pentacene organic thin film Transistor(OTFT) with interface modification layer of polystyrene/chlorosilane composite material was developed.The AFM images show that the growth morphology of pentacene semiconductor film was affected by interface modification.The pentacene grains grown on modified SiO2 substrates with dimensions in the range of 200~400 nm are larger than those grown on bare SiO2 substrates which have sizes less than 150 nm.Large particle size can reduce intergranular interface so as to improve the electrical performance.The output and transfer curve,on/off current ratio,threshold voltage and field-effect mobility of the device were obtained by electric measurements.The transfer curve showed an on/off current ratio exceeding 106 with the off-current of about 10-10 A.The device with interface modification has a maximum field-effect mobility of up to 1.23 cm2·V-1·s-1,compared to the 0.0118 cm2·V-1·s-1 of OTFT on bare SiO2 substrate.