Electron beam evaporated carbon nanotube dispersed SnO2 thin film gas sensor

Carbon nanotube (CNT) is a useful material for gas-sensing applications because of its high surface to volume ratio structure. In this work, multi-wall CNTs are incorporated into tin oxide thin film by means of powder mixing and electron beam evaporation and the enhancement of gas-sensing properties is presented. The CNTs were combined with SnO₂powder with varying concentration in the range of 0.25–5% by weight and electron beam evaporated onto glass substrates. From AFM and TEM characterization, CNT inclusion in SnO₂thin film results in the production of circular cone protrusions of CNT clusters or single tube coated with SnO₂layer. Experimental results indicate that the sensitivity to ethanol of SnO₂thin film increases by the factors of 3 to 7, and the response time and recovery time were reduced by the factors of 2 or more with CNT inclusion. However, if the CNT concentration is too high, the sensitivity is decreased. Moreover, the CNT doped film can operate with good sensitivity and stability at a relatively low temperature of 250–300^∘C. The improved gas-sensing properties should be attributed to the increasing of surface adsorption area of metal oxide produced by CNT protrusion.     

Preparation of SnO2 whiskers via the decomposition of tin oxalate

A new method for preparing SnO₂ whiskers by the decomposition of SnC₂O₄ is suggested. A Whisker-like morphology of a SnC₂O₄ precipitate was attained via the gradual addition of an oxalic acid solution to a hot SnCl₂ aqueous solution (T > 50^∘C). In comparison, when the solution temperature was either lower than 50^∘C or when ethanol was used as the solvent, the SnC₂O₄ precipitate showed an angular and relatively isotropic morphology. The morphology of the SnC₂O₄ precipitate remained even after its thermal decomposition into SnO₂ at 400^∘C indicating that SnC₂O₄ precipitation is a key step in preparing the whiskers. The formation mechanism of SnO₂ whiskers was explained by the supersaturation during the precipitation of SnC₂O₄.     

彩色像片洗印机温度控制系统的设计与实现

本文介绍了彩色像片洗印机温度控制系统的组成及原理,给出了利用DS1820温度传感器实现温度检测与控制软件的设计实例。     

氧传感器作用原理及其固体电解质的制备

简要讨论了ZrO2基氧传感器的作用原理及用于氧传感器的钇稳定氧化锆粉体的几种制备方法。     

传感器的测试技术

本文介绍了以VFP6．0软件，应用在Insb伪币检测传感器中，实现了电脑对传感器的阻值进行自动检测和排序，大大地提高了生产效率，达到理想效果。     

室内移动机器人超声传感器导航网络分布研究

对于室内广域移动机器人,超声波传感器网络是能够保证给定导航准确度的一种有效方法。合理的超声波传感器网络分布是实现超声波网络导航的重要条件。论述了超声波网络合理分布的原则,据此提出并分析了获得合理超声波传感器网络分布的四个步骤,仿真试验结果验证了它的有效性。     

基于屏栅电离室的双参数谱仪研制及其应用

以屏栅电离室为基础，同时引出其阳级和阴极信号，研制了1台能够同时记录两路信号的双参数谱仪，在DEC－3000工作站上编制程序，实现了双维谱数据的获取、显示和存储。利用所建立的谱仪，测量了α放射源的双维谱，计算了α粒子的角分布，并讨论了如何利用角分布来校正活度测量中自吸收和反散射的影响以及改善电离室阳极能谱的能量分辨率。     

A single chip multi-channel surface plasmon resonance imaging system

A single chip, multi-channel surface plasmon resonance (SPR) imaging system has been developed. The equipment has no moving parts and uses a single sensor chip on which multiple channels can be incorporated. A light emitting diode is used as a photon source while a CCD camera forms the detector. The optical configuration has been designed to achieve a uniform illumination of the sample over a fixed area with a range of incident angles. A calibration test using sucrose solutions shows that the sensitivity of the equipment is 4.3×10⁻⁴ refractive index units per pixel line-pair. The use of the system for simultaneous interrogation of different polyelectrolyte thin films, formed by the electrostatic layer-by-layer deposition method, is demonstrated. A reversible pH-dependent response for these organic layers is also reported.     

圆柱体质心测量中转角取值分析

为获得质量非均匀圆柱体质心的三维坐标，测量时需使圆柱体转过一定的角度。分析表明，转角最好取为90度以获得最佳测量效果。如果受条件限制，宜在45度到90度之间选取，尽量避免取小于30度的值。     

基于神经元网络的燃油锅炉烟气氧含量的软

针对目前各种氧含量检测仪表在运行过程中的可靠性差、使用寿命短及价格昂贵等诸多不足，通过探寻锅炉运行中的其他参数与烟气氧含量的映射关系，建立ＢＰ神经元网络，提出了燃油锅炉烟气氧含量的软测量方法。结果表明，其精度完全达到了设计要求。