典型高温薄膜传感器的研究进展

随着航空发动机、燃气轮机、内燃机、石油化工设备等的设计、运行要求不断提高,对典型高温薄膜传感器如高温薄膜应变计、高温薄膜温度计、高温薄膜热流量计的需求越来越迫切。文中介绍了高温薄膜应变计、高温薄膜温度计、高温薄膜热流量计以及多功能集成高温薄膜传感器等典型高温薄膜传感器的研究现状,分析了它们在敏感材料、材料体系、制造工艺和信号传输方面存在的主要问题,可为应用于更严酷环境的高温薄膜传感器的技术研究提供参考

Direct Fabrication of Ultrafine Electrospinning Nanofiber

采用装配有疏水铜网的新型喷头研究了超细纳米纤维的制备.静电纺丝实现之前,首先对铜网进行了疏水处理,并将其安装于喷头前端.静电纺丝过程中,聚合物溶液由精密注射泵输送至喷头处.安装于喷头的铜网可将管道内的聚合物溶液分成多股细流从铜网网孔中流出.从铜网网孔流出的溶液细流受电场力作用被拉伸成多股独立射流,并从喷头携带走聚集的正电荷.受铜网表面疏水性和射流间电荷排斥力的影响,从铜网喷射出的多股射流都将保持其独立的轨迹而不会产生聚集.疏水铜网有利于减小纺丝射流的初始直径,并获得均匀的超细纳米纤维.利用新型的电纺丝喷头成功制备了直径20~80 nM的聚氧化乙烯(PEO)和聚乙烯醇(PVA)超细纳米纤维.实验结果表明,超细纳米纤维的直径随着电纺丝溶液浓度的增加而变大.A novel spinneret assembled with Cu grid was presented in this paper to fabricate ultrafine nanofiber directly.Before electrospinning,hydrophobic treatment was performed on the Cu grid,which was then fixed at the front end of spinneret.During electrospinning,the polymer solution was transferred to the spinneret by the precise syringe pump.Through the holes in the Cu grid,polymer solution flow was divided into several smaller ones.The fine liquid flow from each hole of Cu grid was stretched into individual jets by the electric field force,and the liquid jets carried away the positive charges accumulated on the spinneret.Due to the hydrophobic treatment and the charge repulsive force between charged jets,liquid jets emanated from Cu grid kept their own tracks without aggregation.The initial diameter of liquid jet was greatly decreased by the Cu grid after hydrophobic treatment,and the smaller jet led to finer uniform nanofiber.Polyethylene oxide(PEO) and polyvinyl alcohol(PVA) ultrafine nanofiber with the diameter of 20—80 nm were fabricated by this novel spinneret,and the diameter of ultrafine nanofiber increases with the increase of polymer solution concentration.国家自然科学基金重点资助项目(51035002);国家自然科学基金资助项目(50875222

论生态脆弱带的食物保障与生态系统保护

文章以生态环境极端脆弱的 8省 (自治区 )为例 ,分析了生态脆弱带的社会及经济特征 ,针对生态脆弱带食物保障与生态保护之间关系 ,就新时期我国生态环境脆弱带可持续发展的战略定位问题进行了探

洱海叶绿素a浓度的季节动态和空间分布

2010年5月至2011年4月,对洱海叶绿素a的季节动态、空间分布及其与环境因子的关系进行研究.结果表明,水体中叶绿素a浓度存在明显的季节变化,其变化范围为4.11～24.30μg/L,年平均值为10.4±6.5μg/L,最小值出现在2011年3月,最大值出现在2010年9月.叶绿素a浓度在夏、秋季较高,冬、春季较低.在空间变化上,叶绿素a浓度在南部湖区最大,其次是北部湖区,中部湖区最低.Pearson相关系数和主成分分析表明,洱海叶绿素a浓度在不同湖区中与水温和透明度均呈极显著相关.总氮在北部和南部湖区与叶绿素a浓度均存在一定的相关性,而总磷与叶绿素a浓度在南部湖区存在一定的相关性.根据修正的卡尔森营养状态指数,洱海综合TSI值为50.6,水质处于中营养状态

洱海叶绿素a浓度的季节动态和空间分布

2010年5月至2011年4月，对洱海叶绿素a的季节动态、空间分布及其与环境因子的关系进行研究．结果表明，水体中叶绿素a浓度存在明显的季节变化，其变化范围为4．11～24．30μg／L，年平均值为10．4±6．5μg／L，最小值出现在2011年3月，最大值出现在2010年9月．叶绿素a浓度在夏、秋季较高，冬、春季较低．在空间变化上，叶绿素a浓度在南部湖区最大，其次是北部湖区，中部湖区最低．Pearson相关系数和主成分分析表明，洱海叶绿素a浓度在不同湖区中与水温和透明度均呈极显著相关．总氮在北部和南部湖区与叶绿素a浓度均存在一定的相关性，而总磷与叶绿素a浓度在南部湖区存在一定的相关性．根据修正的卡尔森营养状态指数，洱海综合TSI值为50．6，水质处于中营养状态

Application of Aerosol Jet Technology on Through Hole Metal Interconnection for MEMS Wafer Level Package

在微机电系统(MEMS)圆片级封装中,通孔缺陷极有可能降低芯片与外界电互联的可靠性.采用气浮沉积的方法,在通孔底部沉积纳米银浆,形成低电阻的Ag/Al/SI欧姆接触结构,解决了电极间的电学连接问题.根据AJTM300气溶胶喷射系统的特点,选择50nM粒径的纳米银浆制作通孔Ag/Al/SI欧姆接触结构;在平面圆形Al电极上气浮沉积纳米银浆,改变银浆的烧结温度,用以验证Ag对Al/SI接触电阻的影响;将此法应用于通孔互联结构中,并探究得出最优沉积时间,测量两通孔间的I-V特性.试验结果表明,采用超声雾化方式的气浮沉积方法,在通孔底部沉积15S的纳米银浆,经过300℃的烧结,可以有效填充通孔底部缺陷,并形成较低电阻的Ag/Al/SI接触结构.采用按需喷印的气浮沉积方案对通孔进行沉积,为实现MEMS芯片与外界的电互联提供了新思路.In MEMS wafer level package,the reliability of electrical interconnection between the chip and external environment may be reduced by the breakage of the through-hole.The breakages of the through-hole deteriorate the reliability of electrical interconnection between internal device and external circuit.In order to solve the problem,the Aerosol Jet technique is adopted in this paper,which deposits nano-silver ink at the bottom of the through hole,forming Ag/Al/Si contact structure with low resistance.First,nanosilver ink with particle diameter of 50 nm is deposited on planar round electrodes with Aerosol Deposition to verify the influence of Ag on Al/Si contact resistance.Then,the bottoms of the through holes are filled with silver ink to form Ag/Al/Si contact structure.The I-Vcharacteristics between two through holes are also tested.The experimental result shows that aerosol jet method with ultrasonic atomizer is able to fill the breakage in through hole and form Ag/Al/Si contact structure with low resistance after depositing nano-silver ink for 15 sand sintering under 300 ℃.The Aerosol Deposition method which is deposit on demand,provides a new thinking to achieve the electrical interconnection.国家自然科学基金(51105320

Design and Simulation of Fully-symmetrical Resonant Pressure Sensor

提出了一种基于侧向驱动的全对称谐振式压力传感器结构.谐振结构采用侧向梳齿电容驱动,既保证了驱动力的线性特性,又由于本身的空气阻尼为滑膜阻尼,可以取得较高的品质因子.另外,设计的差分电容结构能进一步提高器件的检测灵敏度.经过AnSyS 10.0的仿真分析总结出谐振结构固有频率受结构参数影响的规律,确定了量程为0~550kPA的谐振式压力传感器具体尺寸,其灵敏度达到了22.602Hz/kPA;分析了温度对谐振结构固有频率的影响,得到-20~60℃下的热灵敏度温度系数为-1.823 3Hz/℃,为后续的温度补偿提供依据;最后通过分析谐振结构的频域响应特性,最终确定了传感器的频域特性曲线以及不同阻尼比下传感器的品质因子,为谐振式压力传感器真空封装的真空度选择提供参考.A fully-symmetrical resonant pressure sensor based upon lateral drive is presented.Resonant structure adopts lateral comb capacitance drive,which can ensure the linear characteristic of driving force,and obtain higher quality factors because its air damping is a kind of slide-film damping.In addition,the differential capacitance structure of the design can further improve the detection sensitivity of device.According to the simulation analysis by ANSYS 10.0,the law by which the natural frequency of the resonator is influenced by the structural parameters can be summarized,the specific size of resonant pressure sensor with a range of 0 to 550 kPa is confirmed,and its sensitivity has reached up to 22.602 Hz/kPa;the impact of temperature on the natural frequency of the resonator is analyzed,knowing that the temperature coefficient of thermal sensitivity is-1.823 3 Hz/℃ and on the condition that temperature is-20 ℃ to 60 ℃,it provides basis for temperature compensation;Finally,based on the analysis on the frequency domain response characteristics of the resonator,ultimately the curve of frequency domain characteristics has been drawn up and the quality factors of sensor under different damping ratios are identified,it offers reliable reference for the choice of vacuum whose vacuum encapsulation of resonant pressure sensor.国家自然科学基金项目(51035002;50875222);中央高校基本科研业务费专项资金项目(2010121039

Electrocatalytic Oxidation of Glucose on CNT/Nanocrystlline TiO_2-Pt Complex Film Electrode in Ionic Liquids

循环伏安法研究葡萄糖在离子液体[EMI]BF4中于碳纳米管/纳米TiO2膜载Pt(CNT/nanoTiO2-Pt)复合膜电极上的电催化氧化.结果表明,CNT/nanoTiO2-Pt电极对葡萄糖氧化具有高催化活性,氧化电位为-0.46V;在组成为离子液体与水的体积比为3∶1的电解液中,葡萄糖的氧化效果最好.电极反应过程受浓差极化控制.Using ionic liquid [EMI]BF4 as the electrolyte,the electrocatalytic oxidation of glucose on carbon nanotubes/nanocrystlline TiO2 film loaded on Pt (CNT/nanoTiO2-Pt) complex film electrode was investigated by cyclic voltammetry. The results found that the CNT/nanoTiO2-Pt complex electrode had high catalytic activity to the electrochemical oxidation of glucose in ionic liquids and the oxidation potential was -0.46 V. The best effect of glucose oxidation was obtained with the volume ratio of ionic liquid to water being 3∶1. The process of electrodic reaction process was concentration polarization controlled.作者联系地址：安徽省功能性分子固体重点实验室,安徽师范大学化学与材料科学学院;Author's Address: Anhui Key Laboratory of Functional Molecular Solids,College of Chemistry and Materials Science,Anhui Normal University,Wuhu 241000,Anhui,Chin

中西科学传统的比较研究(笔谈)

由于中西自然环境以及经济、政治、文化等社会历史背景的不同 ,中西科技传统有着本质性的差异。由于这种差异的深刻影响 ,造成近代科学没有在中国产生 ,也使当前科学在面临大量复杂性现象时有着巨大的困惑。对中华科学传统的某种回归 ,实现东西文化的结合已成为当代国内外学术界许多学者的共识。重新审视中华科学传统 ,大力进行中西科学传统的比较研究 ,这是中国学术界的一项重要任务 ,借此可以推动新世纪世界科学和中国科学的突破与发展