石英晶体谐振器上架点胶工艺质量提升研究

上架点胶工序是石英晶体谐振器生产过程中的薄弱环节,主要失效模式为导电胶粘接不牢。本文对该失效模式的原因和质量影响因素进行了分析,并制定了有针对性的质量提升方案,在优化支架清洗和导电胶搅拌工艺的同时,增加了质量提升固化措施,为产品质量提供了有效保证。

Density functional theory study of NO_2 -sensing mechanisms of pure and Ti-doped WO_3 (002) surfaces

Density functional theory （DFT） calculations are employed to explore the NO2-sensing mechanisms of pure and Ti-doped WO3 （002） surfaces. When Ti is doped into the WO3 surface, two substitution models are considered： substitution of Ti for W6c and substitution of Ti for Wsc. The results reveal that substitution of Ti for 5-fold W forms a stable doping structure, and doping induces some new electronic states in the band gap, which may lead to changes in the surface properties. Four top adsorption models of NO2 on pure and Ti-doped WO3 （002） surfaces are investigated： adsorptions on 5-fold W （Ti）, on 6-fold W, on bridging oxygen, and on plane oxygen. The most stable and likely NO2 adsorption structures are both N-end oriented to the surface bridge oxygen Olc site. By comparing the adsorption energy and the electronic population, it is found that Ti doping can enhance the adsorption of NO2, which theoretically proves the experimental observation that Ti doping can greatly increase the WO3 gas sensor sensitivity to NO2 gas.

巾帼建功展风采 水晶玫瑰谱新篇——记航天科工203所工艺师王莉

有人说女人似水，但她们却有不同于水的坚毅；有人说女人如花，但她们却有比花更长久的芳华。在1997年毕业于山东大学，二十余年间，先后在中电二十七所、西迪斯天津分公司、航天科工203所的工作岗位上与石英晶片及由此制造出的晶体谐振器、振荡器相伴，将自己的青春奉献给了挚爱的晶体事业。

The light-enhanced NO_2 sensing properties of porous silicon gas sensors at room temperature

The NO2 gas sensing behavior of porous silicon（PS） is studied at room temperature with and without ultraviolet（UV） light radiation.The PS layer is fabricated by electrochemical etching in an HF-based solution on a p ＋-type silicon substrate.Then,Pt electrodes are deposited on the surface of the PS to obtain the PS gas sensor.The NO2 sensing properties of the PS with different porosities are investigated under UV light radiation at room temperature.The measurement results show that the PS gas sensor has a much higher response sensitivity and faster response-recovery characteristics than NO2 under the illumination.The sensitivity of the PS sample with the largest porosity to 1 ppm NO2 is 9.9 with UV light radiation,while it is 2.4 without UV light radiation.We find that the ability to absorb UV light is enhanced with the increase in porosity.The PS sample with the highest porosity has a larger change than the other samples.Therefore,the effect of UV radiation on the NO2 sensing properties of PS is closely related to the porosity.

Ab-initio density functional theory study of a WO_3 NH_3-sensing mechanism

WO3 bulk and various surfaces are studied by an ab-initio density functional theory technique. The band structures and electronic density states of WO3 bulk are investigated. The surface energies of different WO3 surfaces are compared and then the （002） surface with minimum energy is computed for its NH3 sensing mechanism which explains the results in the experiments. Three adsorption sites are considered. According to the comparisons of the energy and the charge change between before and after adsorption in the optimal adsorption site Olc, the NH3 sensing mechanism is obtained.

Density functional theory study of the interaction of H_2 with pure and Ti-doped WO_3 (002) surfaces

Density functional theory （DFT） calculations are conducted to explore the interaction of H2 with pure and Tidoped WO3 （002） surfaces. Four top adsorption models of H2 on pure and Ti-doped WO3 （002） surfaces are investigated respectively, they are adsorption on bridging oxygen Olc, absorption on plane oxygen O2c, absorption on 5-fold W5c （Ti）, and absorption on 6-fold W6c. The most stable and H2 possible adsorption structure in the pure surface is H-end oriented to the surface plane oxygen O2c site, while the favourable adsorption sites for H2 in a Ti-doped surface is not only an O2c site but also a W6c site. The adsorption energy, the Fermi energy level EF, and the electronic population are investigated and the H2-sensing mechanism of a pure-doped WO3 （002） surface is revealed theoretically： the theoretical results are in good accordance with our existing experimental results. By comparing the above three terms, it is found that Ti doping can obviously enhance the adsorption of H2. It can be predicted that the method of Ti-doped into a WO3 thin film is an effective way to improve WO3 sensor sensitivity to H2 gas.