From Geometry to Activity: A Quantitative Analysis of WO3/Si Micropillar Arrays for Photoelectrochemical Water Splitting

The photoelectrochemical (PEC) activity of microstructured electrodes remains low despite the highly enlarged surface area and enhanced light harvesting. To obtain a deeper understanding of the effect of 3D geometry on the PEC performance, well‐defined WO₃/n‐Si and WO₃/pn‐Si micropillar arrays are fabricated and subjected to a quantitative analysis of the relationship between the geometry of the micropillars (length, pitch) and their PEC activity. For WO₃/n‐Si micropillars, it is found that the photocurrent increases for WO₃/n‐Si pillars, but not in proportion to the increase in surface area that results from increased pillar length or reduced pillar pitch. Optical simulations show that a reduced pillar pitch results in areas of low light intensity due to a shadowing effect. For WO₃/pn‐Si micropillar photoelectrodes, the p–n junction enhances the photocurrent density up to a factor of 4 at low applied bias potential (0.8 V vs RHE) compared to the WO₃/n‐Si. However, the enhancement in photocurrent density increases first and then decreases with reduced pillar pitch, which scales with the photovoltage generated by the p–n junction. This is related to an increased dead layer of the p–n junction Si surface, which results in a decreased photovoltage even though the total surface area increases.     

具有带外抑制特性的Ka波段低功耗低噪声放大器

基于0.15μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺,成功研制了一款30~34 GHz频带内具有带外抑制特性的低功耗低噪声放大器(LNA)微波单片集成电路(MMIC)。该MMIC集成了滤波器和LNA,其中滤波器采用陷波器结构,可实现较低的插入损耗和较好的带外抑制特性;LNA采用单电源和电流复用结构,实现较高的增益和较低的功耗。测试结果表明,该MMIC芯片在30~34 GHz频带内,增益大于28 dB,噪声系数小于2.8 dB,功耗小于60 mW,在17~19 GHz频带内带外抑制比小于-35 dBc。芯片尺寸为2.40 mm×1.00 mm。该LNA MMIC可应用于毫米波T/R系统中。     

含1.2%铝TRIP钢中残留奥氏体的EBSD研究

残留奥氏体的含量、颗粒尺寸与分布及其稳定性是相变诱导塑性（TRIP）钢获得优良使用性能的关键。马钢试制成功含1.2%铝的TRIP-600钢板,作者用场发射枪扫描电镜EBSD技术对该TRIP钢的残留奥氏体形态、分布与体积分数进行了实验研究。结果表明：实验钢中的奥氏体主要呈细小颗粒状、尺寸在几微米以下,弥散分布于铁素体晶界和晶粒内。EBSD与X-射线衍射测得实验钢板半厚度区的奥氏体体积分数分别为2%和11.4%。本文讨论了EBSD技术测定TRIP钢奥氏体分数引入误差的主要因素。采集图像的步长、试样分析区的选取及试样制备技术等是影响实验结果的重要因素。     

振兴电子专用设备制造业关键是理“才”

电子专用设备制造行业,作为我国电子工业规模化、产业化发展和实现民族制造的基础工业,适应终端产品的"轻、薄、短、小"发展趋势,正在进入一个高技术、高可靠、高精度、多功能、智能化、小型化、自动化发展的重要时期。其开发和研制具有技术要求高、技术人员需要量大、零件加工难度大、国内行业水平与国际差距较大等不同于其他行业的特点。要满足这一特点要求,必须有足够的人才保证。从电子专用设备制造的特殊性考虑,目前急需的人才主要有以下几方面:一是复合性人才。二是电器及自动化控制人才,三是计算机技术推广及应用人才,四是电子产品生产工艺研究人才。在专业技术人员队伍建设方面,主要应做好以下几方面工作:1、要不断补充新的专业技术人员,以新生力量改善人员构成,激活人力资源管理上的"惯性"现象。2、要重视知识更新和人员"充电"工作。3、要注意建立多层次有机结合,不同人员分工明确的专业技术人员队伍。4、要在保证待遇基础上,突出事业留人和感情留人。5、建立科学的人才成长和激励机制,努力为新科技人才施展才华、成就事业搭建大舞台。     

A Receiver in a Millimeter Wave Radiometer for Atmosphere Remote Sensing

A millimeter wave radiometer system with high resolution is described in this paper, which was used for remote sensing of integrated water vapor and integrated liquid water in the troposphere. A novel receiver technique was adopted in the radiometer system to deracinate an impact of the receiver gain shift on its precision and improve its performance. Measured results show that this radiometer system has enough stability in long time measurement and capability to measure atmospheric brightness temperature.     

基于矢量映射的多约束服务质量路由计算

针对多维矢量计算多约束服务质量路由出现实际传输路径与源节点期望路径并非一致问题,研究提出矢量映射方式的多约束服务质量路由计算方法。通过数学方法和物理概念相结合的方式,从原理上阐述了新算法矢量映射的合理性,并通过算例和仿真实验方式验证,新算法只需一次性计算就可以获得源节点到各节点保持路径一致的路由。     

BP神经网络在土壤水分预测中的应用

土壤水分预测是一个复杂的非线性系统,受土壤复杂结构和气象因子影响显著,很难建立一个理想的土壤水分预测数学模型。本文利用BP人工神经网络方法建立了土壤水分预测模型,该模型的预报精度较高,其最大绝对误差为3．12％,最小绝对误差为0．63％,平均绝对误差为1．38％。预测结果表明应用BP神经网络建立的土壤水分数学模型适用于土壤水分的预测,能够比较准确的预测土壤水分,具有较好的预测精度。     

一种实用化的数字体温测量算法及其ASIC实现

传统电子体温计芯片采用大量复杂模拟模块,功耗和成本都较高.文章提出了一种适合电子体温计芯片采用的温度测量算法,基于上华(CSMC)1.0μm MGLVCMOS标准工艺,设计出实用化的数字体温测量电路,并绘制了整个电路的版图.利用Spectre、Verilog_XL及Matlab对系统电路进行仿真测试,结果显示所设计的数字体温测量电路在+32.0℃～+42.0℃(+90.0°F ～+108.0°F)的温度范围内可以实现摄氏和华氏两种模式的测量,具有0.1℃(0.2°F)的精度,1.5V电源电压下系统平均电流仅为100μA,整个电路呈现低功耗和高集成度的特点.     

An ultra-low-power CMOS temperature sensor for RFID applications

An ultra-low-power CMOS temperature sensor with analog-to-digital readout circuitry for RFID applications was implemented in a 0.18-μm CMOS process.To achieve ultra-low power consumption,an error model is proposed and the corresponding novel temperature sensor front-end with a new double-measure method is presented.Analog-to-digital conversion is accomplished by a sigma-delta converter.The complete system consumes only 26μA@1.8 V for continuous operation and achieves an accuracy of±0.65℃ from-20 to 120℃ after calibration at one temperature.     

直流弱电流测量与误差分析

介绍了分流式和反馈式电流表测量直流电流的基本原理。根据静电计测量直流弱电流信号的电路模型,分析了电流表输入端压降、源内阻、源电容、正确接地、连接导线、环境湿度等因素产生的测量误差,并且给出了相应的解决方案。