膜催化反应器的分析与模拟

分析了膜反应器的出现、发展和最新研究。论述了几种膜反应器中气体的传递机理,定量分析了膜反应器中控制传递与反应的模型方程式以及计算机模拟和实验研究结果。最后评价了两类膜反应器的操作特性,以⊿n<0、⊿n=0和⊿n>0三类不同的催化反应作为模型反应与传统的PFR 和 MFR 的操作特性作了对比。     

Low-frequency wide-band hybrid energy harvester based on piezoelectric and triboelectric mechanism

Recently,hybrid energy harvester has been considered as an attractive potential approach to response the worldwide energy crisis due to the combination of advantages from different harvesting mechanism.In this paper,a novel low-frequency wide-band hybrid energy harvester based on piezoelectric and triboelectric mechanism is presented and systematically studied including structural design,fabrication process,working principle simulation and measurement.With a vibrational excitation,the polyvinylidene fluoride(PVDF) cantilevers will vibrate and impact the polydimethylsiloxane(PDMS) film on the substrate,producing a piezoelectric output as well as a triboelectric output.The structural parameters of each cantilever are optimized using finite element simulation,and the well-designed PVDF cantilevers with controllable PDMS mass not only reduce the device working frequency but also enlarge the bandwidth.Under a sweep-frequency test,three voltage peaks induced by the piezoelectric part are observed at 15,32.5 and 47.5 Hz,with the value of 320,288 and 264 mV,respectively.With the combined triboelectric part,a 20 V peak-peak voltage is generated at 15 Hz.The electrical driving ability of this hybrid energy harvester also has been demonstrated by lighting up a commercial light emitting diode(LED).     

A very sensitive ion collection device for plasma-laser characterization

In this paper a very sensitive ion collection device, for diagnostic of laser ablated-target plasma, is described. It allows for reducing down to few microvolts the signal threshold at digital scope input. A standard ion collector is coupled to a transimpedance amplifier, specially designed, which increases data acquisition sensitivity by a gain ≈1100 and does not introduce any significant distortion of input signal. By time integration of current intensity, an amount of charge as small as 2.7 × 10(-2) pC can be detected for photopeak events.     

A wind-flutter energy converter for powering wireless sensors

This paper describes a low-speed wind energy harvesting system that transfers aerodynamically induced flutter energy into electrical energy. A random airflow generates mechanical vibrations due to the fluid-structure interaction between a flexible belt and the airflow. An electromagnetic resonator with copper coils and a permanent magnet is designed to efficiently harvest electrical energy from the induced mechanical vibrations. Different groups of springs are compared at various wind conditions to maximize the power output. Typically ∼7 mW of electrical energy can be obtained at ∼3 m/s wind speed with a 1 m long belt. A power conditioning circuit with a charge pump and a DC-DC converter is used to convert the generated voltage into a stable 3.3 V DC for consumption. It is demonstrated that this generator can be used to drive a commercial wireless temperature sensor.     

基于ABAQUS真空联合覆水预压法仿真模拟与分析

以龙湾燃煤电厂V-3区采用真空联合覆水预压处理软土地基工程为基础,利用大型通用有限元ABAQUS程序中的孔压边界条件模拟真空荷载,运用二维固结有限元进行模拟,分析其在真空联合覆水预压过程中的沉降情况以及超孔压分布情况,对类似工程有借鉴和指导意义。     

石墨化炉的供电特点及发展趋势

通过对石墨化炉的特点及其供电方面的有关问题的分析，论述了石墨化炉供电的特点及其发展的趋势，并对石墨化炉在交、直流电源供电方面提出了看法，以不断提高石墨化炉供电的设计水平．     

氧化亚铜微米晶的水热合成与生长机理

氧化亚铜是一种重要的P型半导体材料，目前因其独特的可见光催化性能在科研领域引起了广泛的重视。以CuSO4·5H2O为铜源，以α—D-葡萄糖为还原剂，并利用水热还原反应合成出了不同形貌的Cu2O微米晶。利用X射线粉末衍射分析（XRD）、透射电子显微镜（TEM）对合成的样品进行了形貌与结构的表征与分析。结果表明所合成的晶粒尺寸均匀且分散性好。讨论了不同条件下的晶粒生长机理，运用扩散机制与聚集机制解释了不同形貌的成因。     

A GROUP-CONTRIBUTION METHOD INVOLVING SPECIFIC GRAVITY AS A PARAMETER FOR ESTIMATING CRITICAL TEMPERATURES

A new group-contribution method involving specific gravity as a parameter is proposed for predicting criticaltemperature.Being appliable to all kinds of organic compounds,it gives an average percent deviation of 0.88%for 93 compounds and is particularly useful to those substances for which the normal boiling points are stillunknown.     

Micropuncture studies of glucose transport in the dog: mechanism of renal glycosuria

Clearance and micropuncture studies were performed in 23 dogs without glucose loading to examine the tubule mechanism of renal glycosuria. Studies were carried out in three groups of animals before and after 10% extracellular volume expansion, and administration of maleic acid in low dose at 150 mumol/kg and in high dose at 300 mumol/kg. Specific hexokinase methods were used for the determination of glucose in tubule fluid and urine. Under control conditios, glucose reabsorption occurred predominantly in the proximal tubule. In all three groups, proximal tubule reabsorption of both sodium and glucose was inhibited in the second phase, showing a good correlation between the two. In contrast, fractional urinary glucose excretion remained unchanged after volume expansion and low-dose maleic acid, indicating reabsorption of virtually all the increased glucose load at a further "distal" site. On the other hand, significant glycosuria developed after high-dose maleic acid that was a result of reduced glucose reabsorption in the distal nephron, in addition to the proximal effect. It was concluded that distal glucose transport plays a significant role in regulating urinary glucose excretion and maintains renal thershold for glucose,