贮氢负极的电化学交流阻抗特性研究

通过试验测得金属氢化物电极的电化学交流阻抗谱（ＥＩＳ）,经过分析得到该电极的等效电路图。为了分析电极在不同状态下的阻抗及不同种类电极的阻抗,ＥＩＳ被用于其分析：（１）不同带电态的电极;（２）不同集流体电极;（３）不同化成态的电极。试验结果表明：（１）随放电深度的增加,电荷传递阻抗Ｒ７有先减小后增大的趋势,温伯格阻抗对应电导逐渐减小;对此进行了理论分析;（２）泡沫镍在电极中起到的集流作用不一定明显优于冲孔镍带,但可能由于镍的电催化作用,能减小电极反应的电子转移步骤阻抗;（３）以充放电方式的电化学化成主要是减小电荷转移阻抗,而对温伯格阻抗无明显影响。     

真空预冷中捕水器与真空泵的优化匹配研究

真空预冷过程中捕水器能力与真空泵抽气能力匹配决定着预冷过程的质量。通过对预冷过程中水蒸汽为理想气体的假定,分别计算了捕水器和真空泵在匹配时所需要的能耗。在这基础上,对真空预冷系统所需要的能耗进行了计算,并在一台真空预冷实验台上对装载率为60％时的白菜了实验研究,并和理论结果进行了比较。结果表明,在确定的工作条件下,单位时间内的能耗只是与抽气量有关,而整体能耗则取决于所需要预冷的果蔬,与系统参数无关。     

Effects of diazonaphthoquinone groups on photosensitive coating

Diazonaphthoquinone (DNQ)‐novolak photosensitive materials are important in lithography. DNQ groups play an important role in the photosensitive coating. However, there are no reports on the relationship between content of DNQ groups and properties of the coating. The properties include alkali resistance, isopropanol resistance, and abrasion resistance, the key factors in lithography. The experimental results show proper content of DNQ groups can ensure higher sensitivity, finer resolution, and better abrasion resistance in lithography. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

铁粉还原应用于α-卤代羰基化合物的卤素消除研究

对铁粉还原应用于α-卤代羰基化合物的卤素消除进行了研究,实验证明,铁粉不仅可用于4-溴-2-氯-2-甲基-卜茚酮的脱氯反应,也可用于2,4-二溴-5-甲氧基-6-叔丁基-2-甲基-l-茚酮的脱溴反应,并且经过了工业化验证,给出了工业化放大时的建议.     

Synthesis of ZSM‐5 by hydrothermal method with pre‐mixing in a stirred‐tank reactor

This work proposed a synthesis route of ZSM‐5 via the hydrothermal method with premixing in a stirred tank reactor (STR). Effects of various operating conditions, including pre‐mixing time, molar ratio of SiO₂/Al₂O₃, TPAOH (organic template agents) concentration, NaCl (alkali metal cations) concentration, crystallization temperature, and crystallization reaction time, on the average particle size (PS) and particle size distribution (PSD) were investigated. It was found that the pre‐mixing time in the STR significantly affect the formation of proto‐nuclei in premixing process and crystal growth in hydrothermal reaction process, and consequently influence the PS and PSD of the prepared ZSM‐5. ZSM‐5 with good thermal stability, a PS of 380 nm, PSD of 0.17–0.9 µm, pore diameter of 2.31 nm, pore volume of 0.19 cm³ · g^?1 and specific surface area of 337.25 m² · g^?1 were obtained under the optimal conditions of a crystallization reaction time of 24 h, a crystallization temperature of 130 °C, a molar ratio of SiO₂/Al₂O₃ of 200, a TPAOH concentration of 3.5 mol · L^?1, NaCl concentration of 0.3 mol · L^?1, and a pre‐mixing time of 5 h. This work indicated that the operating conditions including premixing time have a significant effect on its PS and PSD.     

Formation of GaN nanostructures with various morphologies by photo-assisted electroless chemical etching

Interaction of GaN crystal faces with chemicals is crucial to understand why various nanostructures are formed during the etching process. We have prepared GaN nanostructures by a photo-assisted electroless chemical etching method in solutions containing KOH and K₂S₂O₈. Morphology nanostructure GaN layers grown by molecular beam epitaxy (MBE) and hydride vapor phase epitaxy (HVPE) were studied. For the GaN layers grown by MBE, the etching reaction process starts at grain boundaries and dislocation domains on the surface and inverted hexagonal pyramids are eventually formed. For the GaN layers grown by HVPE, scattered etch pits with well-defined hexagonal facets are observed after the etching process.     

冷弯型钢输电铁塔主斜材连接方式的理论和试验研究

冷弯薄壁型钢是一种高效经济型钢材，传统输电铁塔设计采用的都是普通热轧型钢。随着电力事业的不断发展开发利用新型输电铁塔势在必行。为此，本文在研究了采用这种新型钢材设计输电铁塔强度问题之后（可省钢材３０％左右）。又通过理论和试验对构件节点连接方式的问题做了进一步研究。为其应用提供了理论根据。     

一种考虑加热器效率的自适应PID温控方法

某化学分析仪器需对处理过程进行温度控制,控制涉及多个部位,各部位加热器效率并不相同,并且每个控制点在不同的处理流程中存在不同的目标温度.为解决上述问题,采用PID控制和模糊控制相结合的自适应温控方法,根据被控系统的实际响应,运用模糊推理,考虑各加热器的效率,目标温度与环境温度差等因素,实现温控过程中PID参数的自适应调...     

航空地面电源检测系统软件设计

航空地面电源检测系统采用PCI1710采集卡采集数据,通过小波变换技术实现波形品质分析,得出电压、电流、频率计算的数学模型,使数据的采集更加迅速、可靠.