Nitrogen Dioxide Sensing Properties and Mechanism of Copper Phthalocyanine Film

Copper phthalocyanine film, a p-type organic semiconductor, is synthesized by vacuum sublimation and its surface morphology is characterized by SEM. A silicon-based copper phthalocyanine film gas sensor for NO2 detection is fabricated by MEMS technology. The results show that the resistance and sensitivity of copper phthalocyanine film decrease obviously as the NO2 concentration increases from Oppm to lOOppm. However, the sensitivity nearly keeps a constant of O. 158 between 30 ppm and 70 ppm. The best working temperature of the gas sensor is 90℃ for NO2 gas concentrations of lOppm, 20ppm and 30ppm, which is much lower than that of general metal oxide gas sensor.     

Effect of Reactor Pressure on Qualities of GaN Layers Grown by Hydride Vapour Phase Epitaxy

The influence of reactor pressure on GaN layers grown by hydride vapour phase epitaxy （HVPE） is investigated. By decreasing the reactor pressure from0. 7 to 0.5 mm, the GaN layer growth mode changes from the island-like one to the step flow. The improvements in structural and optical properties and surface morphology of GaN layers are observed in the step flow growth mode. The results clearly indicate that the reactor pressure, similarly to the growth temperature, is One of the important parameters to influence the qualities of GaN epilayers grown by HVPE, due to the change of growth mode.     

材料化学课程思政的探索与实践*——以“常见金属材料”为例

以“金属材料”中的“常见金属材料”为例,从教学内容和教学评价2个方面探讨了材料化学课程的思政教学。从铝合金、铜合金、钢铁等几种常见金属材料的生产、应用等方面将教学内容与思政元素有机融合,在教学评价中融入思政教育,增强学生的创新创业意识、环境保护意识、资源保护意识、民族自豪感和社会责任感,践行“立德树人”的教育理念。     

Dynamic quality of transmission optimization and global impairments control in reconfigurable transparent WDM networks:schemes and demonstrations

<正>Two novel dynamical quality of transmission(QoT) optimization schemes with explicit optimization targets and accurate end-to-end QoT estimation are proposed for reconfigurable transparent wavelength-division multiplexing(WDM) networks.Numerical simulations show that the scheme of quality(Q) best has the best Q factor improvement with large attenuation adjustment.The scheme of Q allowable can achieve minimized number of tuning sites and attenuation adjustment and also improve the Q factor of light path to the required value.In addition,the idea of dynamic QoT optimization and global impairment control has been experimentally demonstrated on a simple mesh network by the cooperation of a control plane and tunable devices.     

语言通信中的一些声学问题

一、概 述 语言通信是研究两处或多处进行语言信息交换的学科.电话通信是语言通信中的一种最主要的手段,它与语言声学、生理声学、电声学和建筑声学等有着密切的关系.本文扼要介绍电话通信中经常遇到的一些声学问题. 二、电话传输质量的主观评价 电话传输系统的传输质量主观评价标准和     

入口压力对天然气超声速液化特性的影响

为研究入口压力对天然气混合物超声速液化特性的影响规律,建立了三维双组分天然气混合物超声速凝结流动数学模型,对Laval喷管内双组分混合物凝结流动进行了数值模拟,得出了沿Laval喷管轴向的参数分布,通过开展双可凝组分气体凝结相变实验,对比发现数值模拟与实验结果基本一致,说明了所建立的数学模型及计算方法的正确性。还研究了入口压力对甲烷-乙烷混合物超声速液化特性的影响,结果表明,保持Laval喷管入口温度及组成不变,增大入口压力,混合气体成核位置前移,成核率、平均液滴半径、液相质量分数均随之增大,即入口压力越大,混合气体在Laval喷管内越易发生凝结,在实际生产中可以通过调节入口压力来促进天然气的凝结,提高Laval喷管的液化效率。     

一种宽输出低纹波开关电源

研制一种由全桥PWM变换器、电压电流双环控制、纳米晶磁芯高频变压器和全桥整流、LC滤波器组成的单相输入、脉宽调制变换器型稳压电源。输出电压为1～100V，最大电流达100A，输出纹波小于0．1％。实现了某工程试验点火对电源的要求。     

基于小子样理论的坦克扭力轴疲劳寿命分析

基于小子样的思想,探讨扭力轴表面缺陷对其疲劳寿命的影响,有助于进一步找到降低扭力轴表面凹坑对扭力轴疲劳寿命影响的方法.