Effects of Sc2O3 and MgO passivation layerson the output power of AlGaN/GaN HEMTs

The low temperature (100°C) deposition of Sc₂O₃ or MgO layers is found to significantly increase the output power of AlGaN/GaN HEMTs. At 4 GHz, there was a better than 3 dB increase in output power of 0.5×100 μm² HEMTs for both types of oxide passivation layers. Both Sc₂ O₃ and MgO produced larger output power increases at 4 GHz than conventional plasma-enhanced chemical vapor deposited (PECVD) SiN_x passivation which typically showed ⩽2 dB increase on the same types of devices. The HEMT gain also in general remained linear over a wider input power range with the Sc₂O₃ or MgO passivation. These films appear promising for reducing the effects of surface states on the DC and RF performance of AlGaN/GaN HEMTs     

EC与~（99m）Tc－GH之间的配体交换反应动力学研究

实验表明，ＥＣ浓度与配体交换反应速度常数无关，体系的ｐＨ值对速度常数和９９ｍＴｃ－ＥＣ的标记率影响较大。测定并计算了不同ｐＨ值的交换反应速度常数。结果表明，为保证用配体交换法制备９９ｍｃ－ＥＣ时９９ｍｃ－ＥＣ的标记率大于９０％，体系的ｐＨ值必须≥８。     

温度,压力对漂移室气体增益的影响

研究了温度及气体压力对漂移室（工作于正比区）气体放大倍数的影响，温度和气体压力的变化范围分别是５￣４０℃及９０￣１０５ｋＰａ。用实验数据拟合得到了函数关系并测量了几种饱和度下函数中的参数值。     

Study on heat conduction and adsorption/desorption characteristic of MIL-101/few layer graphene composite

Journal of Porous Materials - Aiming at the poor heat conduction performance of porous MIL-101 applied in adsorption cooling process, few layer graphene (FLG) was selected as a promising thermal...     

电动车制动能量再生反馈控制研究

研究了电动汽车制动过程中的能量回馈，设计了混合励磁无刷电动机在汽车制动过程的能量再生反馈控制系统。以脉宽调制调压调速系统为例，研究各种制动态下的能量回馈过程。并将其安装在EV6600电动汽车上进行试验，结果表明：该控制系统可达到10%左右的能量回收效率。     

SO_4~（2－）／ZrO_2固体超强酸的失活与再生

初步探索了ＳＯ_４~２－／ＺｒＯ２固体超强酸的失活机理．并着重研究了催化剂的两种再生方法：灼烧法和溶剂洗涤法。催化剂主要是因结焦而失活，高温灼烧能基本恢复催化剂原有活性．且再生效果与灼烧温度有关。溶剂洗涤法有一定的再生能力，但不显著．     

D301树脂分离衣康酸的工艺研究

采用弱碱性阴离子交换树脂Ｄ３０１对发酵法生产的衣康酸进行了分离研究。通过静态交换实验，研究了Ｄ３０１树脂对衣康酸的静态交换动力学，确定了传质机制和影响因素；通过动态交换实验，研究了以硫酸为洗脱剂，以氨水为再生剂的工艺过程，确定了主要工艺参数。     

Propylene epoxidation in a microreactor with electric heating

Gas phase propylene epoxidation on gold catalysts has attracted wide attention from industry and academia due to its high selectivity. However, it suffers from low propylene conversion and rapid catalyst deactivation. Experiments showed that propylene conversion could be increased by raising H₂, O₂, or C₃H₆ concentration in the feed, but the feed compositions were within the explosion limit. It was also shown that the activity of the used catalyst could be fully recovered, but the regeneration temperature was 280 °C, much higher than that for reaction. Therefore a microchannel reactor was devised to suppress explosion and was constructed with Fecralloy, to raise the temperature rapidly for catalyst regeneration by electric heating. In two minutes the temperature of the reactor could be raised from 50 to 300 °C. Catalysts were coated on the alloy belt by dip coating, and the performance of the reactor was evaluated under different operating conditions. Results showed that in the microreactor the overall reaction rate was controlled mainly by the intrinsic reaction rate, and also influenced by film diffusion to a certain extent. The deactivated catalyst was regenerated in the microchannel reactor and the activity was fully recovered.     

The influence of F doping on the activity of PbO2 film electrodes in oxygen evolution reaction

The PbO₂ and F⁻-doped PbO₂ (F-PbO₂) film electrodes have been prepared by an electrodeposition process onto platinum substrate. The changes of their electrochemical activity for oxygen evolution (OE) reaction with accelerated electrolysis time have been studied. The results show that the activity of the electrodes decreases with increasing electrolysis time. This can be attributed to the conductivity variations, which are caused by the decrease of the oxygen vacancy concentration in PbO₂ films during OE. The mechanism of the decrease of the oxygen vacancies has been investigated. For F-PbO₂ film electrodes, though its electrochemical activity is somewhat lower than that of undoped one, its activity stability is much higher in comparison with that of PbO₂. The influence of F⁻ doping on the activity of PbO₂ film electrodes has been also discussed.