97dB动态范围、带温度补偿的MEMS电容传感器读出电路

This paper presents a charge-sensitive-amplifier(CSA)based readout circuit for capacitive microelectro-mechanical-system(MEMS)sensors.A continuous-time(CT)readout structure using the chopper technique is adopted to cancel the low frequency noise and improve the resolution of the readout circuits.An operational trans-conductance amplifier(OTA)structure with an auxiliary common-mode-feedback-OTA is proposed in the fully differential CSA to suppress the chopper modulation induced disturbance at the OTA input terminal.An analog temperature compensation method is proposed,which adjusts the chopper signal amplitude with temperature variation to compensate the temperature drift of the CSA readout sensitivity.The chip is designed and implemented in a 0.35 m CMOS process and is 2.1 2.1 mm2in area.The measurement shows that the readout circuitachieves0.9aF/√Hz capacitive resolution,97dBd ynamic range in 100Hz signal bandwidth,and 0.8mV/fF sensitivity with a temperature drift of 35 ppm/℃ after optimized compensation.     

天津市中心城区机构养老设施布局均衡性研究

从公平和效率两个角度,运用洛伦兹曲线、覆盖率和引入综合服务能力因子的潜能模型等方法测度天津市中心城区机构养老设施空间布局的均衡性.研究表明:天津市中心城区各街道人均机构养老设施量和可达性存在差异,呈现出西部和东南部较高、周围逐渐减小的趋势;机构养老设施在各区域布局效率差异较大,部分区域存在设施与人口错位分布以及服务范围...     

采煤机滚筒优化设计

基于模型试验原理,作者对采煤滚筒参数进行了优化,并开发了用于手煤机滚筒优化设计的软件。将模型试验与优化理论结合,使采煤滚筒的分析、设计更为有效。     

SURFACE MODIFICATION OF TITANIUM FILMS WITH SODIUM ION IMPLANTATION： SURFACE PROPERTIES AND PROTEIN ADSORPTION

Sodium implanted titanium films with different ion doses were characterized to correlate their ion implantation parameters. Native titanium films and ion implanted titanium films were characterized with combined techniques of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and light microscopy (LM). The surface presented increased sodium concentration on treated titanium films with ion dose increasing, except for the group with the highest ion dose of 4× 1017 ions/cm2. XPS depth profiling displayed that sodium entered titanium film around 25-50 nm depth depending on its implantation ion dose. AFM characterization showed that sodium ion implantation treatment changed the surface morphology from a relatively smooth titanium film to rough surfaces corresponding to different implantation doses.After sodium implantation, implanted titanium films presented big particles with island structure morphology. The surface morphology and particle growth displayed the corresponding trend.Fibrinogen adsorption on these titanium films was performed to correlate with the surface properties of treated titanium films. The results show that protein adsorption on ion-implanted samples with dose of 2 × 1017 and 4 × 1017 are statistically higher (p ＜ 0. 01) than samples treated with dose of 5×1016 and 1 ×1017, as well as the control samples.     

VFTO下SF_6间隙及绝缘子沿面预放电电流特性

对SF6气体间隙及绝缘子沿面的预放电电流进行了测量。测量结果证实 ,正极性VFTO作用下SF6的击穿遵从先导击穿机理 ;而负极性VFTO作用下SF6的击穿一般遵从茎先导机理或流注放电导致直接击穿。气压大小直接影响先导的起始电压及先导的间隔时间。存在绝缘子时 ,先导形成时间间隔及步长变短 ,且在快速振荡冲击电压作用下会出现“逆放电”现象 ,这有利于先导形成 ,从而降低了闪络电压。     

机载雷达罩曲面FSS阵图形制作研究

采用电镀铜箔蚀永不地和图形电镀反贴法,研究了雷达工面ＦＳＳ阵图形制作工艺,解决了液态光抗蚀油墨的立体涂布、底片分割贴装、旋转狭缝曝光及蚀刻问题;另外还解决了图形电镀、压模反贴问题。图形精度分别达到±０．０８ｍｍ和±０．０６ｍｍ,满足≤±０．１０ｍｍ的图形公差要求。     

智能化分布式医学图像管理

一般的图像归档和通信系统（PACS）的管理缺乏智能性,存储及查询图像效率低。在广东石龙人民医院的PACS中,采用多级分布式存储体系,引入基于图像内容的查询和图像理解专家系统技术。通过显示工作站图像访问时间评估,采用智能化体系后,在存储管理、查询速度及灵活性上都有了较大的提高。     

磷酸盐涂层研究进展及其应用

随着世界环保压力与节能压力的剧增,绿色涂层已经成为金属腐蚀防护的发展趋势.磷酸盐涂层是一种机械强度高、热稳定性好、耐腐蚀且无毒环保的无机涂层.相较于金属涂层和无机硅涂层,磷酸盐涂层因其制备方法简便以及特殊的性能优势,受到越来越多的关注,在建筑、汽车、航海、航空航天、医疗等领域已取得广泛运用.分别介绍了反应固化型磷酸盐涂层和磷酸盐转化膜.首先阐述了反应固化型磷酸盐涂料的组成,包括胶黏剂、固化剂、功能填料和其他添加剂,并分别介绍了胶黏剂的合成及配比研究、固化剂的固化机理和选择、功能填料的选择对性能的影响以及其他添加剂对涂料整体性能和实用方面的影响.然后对磷酸盐转化膜这类特殊的磷酸盐涂层的成膜机理以及常用磷化液组成进行了介绍.成膜机理主要包括基体的电化学溶解、磷酸盐的结晶和成长、磷酸盐转化膜溶解与形成之间的动态平衡三个步骤.磷化液包括锌系、铁系、钙系、锰系磷化液以及它们之间的组合.此外,总结了磷酸盐涂层在防腐蚀、耐高温和一些其他性能方面的应用现状.最后对磷酸盐涂层今后的发展趋势进行了展望,指出磷酸盐涂层在航空航天和石油化工等领域的研究重点.     

某深基坑地下连续墙安全评估与分析研究

通过对地下连续墙的混凝土抗压强度、抗渗性能、钢筋配置及外观质量等进行检测,对槽段接头处内部夹泥进行取芯验证,并对墙体进行承载力及裂缝验算,分析地下连续墙产生问题、缺陷的原因,同时探索检测评估地下连续墙适用的方法和技术。根据实际情况,提出合理的处理建议、方案,为后期处理做好充分的准备工作,减少工程损失,提高工程进度。为今后地下连续墙的检测评估积累经验。     

Numerical simulation of the effects of protrusion on DC arc anode attachment

The attachment of the DC arc on the anode is usually affected by surface morphology such as protrusions due to ablation or melting deformation.A three-dimensional thermodynamic and chemical non-equilibrium model is used to numerically simulate the effect of artificially assumed surface protrusions on the arc anode attachment.The numerical simulation results show that the arc deflects toward the protrusions on the anode and attaches to them in a constricted mode,resulting in an increase in the temperature of the arc attachment region.The analysis shows that the presence of protrusion on the anode surface changes the electric field distribution,intensifies the degree of thermodynamic and chemical non-equilibrium in its vicinity,further influences the chemical kinetic process of the plasma around it,which is the main reason for the deflection of the arc toward the protrusions and the arc anode attachment in a constricted mode.In order to verify the numerical simulation results,verification experiments are also performed using similar size scale anode protrusion,and the results showed that the presence of protrusion can indeed cause the deflection of the arc and even cause the ablation of the protrusion.