Serially-connected series-stub resonators for narrowband coplanar-stripline bandpass filters

In this letter, a coplanar stripline (CPS) series resonator composed of serially-connected series-stubs is proposed. This kind of resonator provides two transmission zeros close to the resonant frequency. With the proposed structure, the reactance slope parameters of the resonators are significantly increased and adjustable by changing the length ratio of the two series stubs. This is useful for designing narrowband filters which is difficult to realize with conventional series CPS resonators. The structures of the resonators are optimized for a lower radiation loss and used to design a narrowband Chebyshev bandpass filter. The simulation and experimental results show that the proposed filter provides multiple transmission zeros and high selectivity.     

影响喷气燃料与橡胶相容性的因素

采用几种具有不同初始物理性能及不同丙烯腈含量、不同硫化剂和硫化程度的丁腈橡胶，考察了其配方和物理性能对采用不同工艺条件生产的喷气燃料的相容性。结果表明，喷气燃料与橡胶的相容性不仅与喷气燃料的加工工艺有关，而且与橡胶的组成及其制备工艺有关。采用非加氢工艺生产的喷气燃料与橡胶的相容性好于采用加氢工艺(特别是加氢裂化工艺)生产的喷气燃料。橡胶材料的初始力学性能的好坏并不完全决定其与喷气燃料相容性的好坏，橡胶材料的耐过氧化物侵蚀能力才是影响相容性好坏的主要因素。橡胶的组成和其制备工艺决定了橡胶在喷气燃料中萃取物的数量和组成，不同萃取物的综合作用给相容性带来不同程度的影响。用硫作硫化剂的橡胶虽然原始强度低于用过氧化物作硫化剂的橡胶，但前者与喷气燃料的相容性却远好于后者。     

离心式冷水机组在线监控系统研究

阐述了离心式冷水机且在线监控系统的工作特点以及对监控的要求，说明了在线监控系统的基本配置，关键技术点和功能模块化的软硬件设计。     

Structure evolution of conductive polymer composites revealed by solvent vapor induced time-dependent percolation

The authors of this paper synthesized a series of amphiphilic triblock copolymers of polystyrene-b-poly(ethylene glycol)-b-polystyrene (PS-PEG-PS) having different PEG/PS ratios with nearly identical molecular weights of the entire copolymers. The interfacial interactions in the composites consisting of carbon black and the copolymers can thus be tailored. When these conducting composites are exposed to certain solvent vapors, their electrical resistances greatly increase, showing the gas sensitivity. The present work indicated that this switching behavior is controlled by the structural relaxation of the composites because matrix swelling acts as the main mechanism. The response time has been correlated with absolute temperature by Arrhenius equation, and the estimated activation energy reflects mobility of the fillers involved in the solvent induced expansion of the surrounding polymer. Therefore, by using the gas sensibility of the conductive composites, the structure evolution of the composite materials in solid state and the effect of filler/matrix interfacial interaction on the relaxation property of the matrix polymer has been inspected. It was found that lower activation energy represents stronger interfacial interaction in case good solvent of the matrix was used for the test.     

轧后穿水冷却工艺对棒材组织性能的影响

针对轧机产量提高后冷床冷却能力不足的问题 ,研制开发了棒材轧后穿水冷却技术。通过对小规格 2 0MnSiV热轧带肋钢筋进行轧后穿水冷却 ,钢材上冷床温度降低了 90～ 110℃ ,提高了产品质量 ,改善了各项力学性能 ,抗拉强度平均提高了 3 5～ 40MPa ,钢材性能合格率由 97.5 %提高到了 99.6% ,解决了冷床冷却能力不足、制约生产的瓶颈问题。     

油田热采注汽管道在线检测技术现状

稠油热采注汽管道由于长期在高温、高压下运行,极易发生各种损伤,如腐蚀、裂纹、材料退化等,极易造成管道承压能力降低,发生失效事故。如何检测出潜在危险性缺陷,判断注汽管道能否继续使用,是保证注汽管道安全运行的关键问题。探讨了高温压力管道在线检测技术发展现状及其应用范围。     

Lactic acid production from dining‐hall food waste by Lactobacillus plantarum using response surface methodology

BACKGROUND: Food waste generally has a high starch content and is rich in nutritional compounds, including lipids and proteins. It therefore represents a potential renewable resource. In this study, dining‐hall food waste was used as a substrate for lactic acid production, and response surface methodology was employed to optimise the fermentation conditions. RESULTS: Lactic acid biosynthesis was significantly affected by the interaction of protease and temperature. Protease, temperature and CaCO₃ had significant linear effects on lactic acid production, while α‐amylase and yeast extract had insignificant effects. The optimal conditions were found to be an α‐amylase activity of 13.86 U g^?1 dried food waste, a protease activity of 2.12 U g^?1 dried food waste, a temperature of 29.31 °C and a CaCO₃ concentration of 62.67 g L^?1, which resulted in a maximum lactic acid concentration of 98.51 g L^?1 (88.75% yield). An increase in inoculum size would be appropriate for accelerating the depletion of initial soluble carbohydrate to enhance the efficiency of α‐amylase in dining‐hall food waste fermentation. CONCLUSION: A suitable regression model for lactic acid production was developed based on the experimental results. Dining‐hall food waste was found to be a good substrate for lactic acid fermentation with high product yield and without nutrient supplementation. Copyright © 2008 Society of Chemical Industry     

油气吸收回收系统的研究及工业应用——(Ⅱ)工业试验及效果分析

在油气吸收回收系统中型试验的基础上，开发了常温常压吸收法工业化油气回收系统，并进行了工业应用。结果表明，该油气回收系统平均回收率可达95．13％，每年可回收汽油529t；装车期间装车口周围环境大气中总烃浓度平均降低98．06％。企业通过实施油气回收系统，节能及经济效益明显，且很好地改善了装车场所的作业环境，克服了油气排放带来的安全隐患。     

Preparation and Characterization of Carboxymethyl Chitosan and β-Cyclodextrin Microspheres by Spray Drying

Three kinds of carboxymethyl chitosan/β-cyclodextrin microspheres loaded with theophylline were prepared by spray drying intended for pulmonary delivery. Mucociliotoxicity, permeation rate, and drug release characteristics of the product were investigated. The microspheres obtained by spray drying were found to be spherical with smooth or wrinkled surfaces. The mean particle size was between 3.39 and 6.06 µm. The microspheres demonstrated high product yield (43.7-50.2%), high drug loading (13.7-38.1%), and high encapsulation efficiency (86.9-92.8%). FT-IR indicated that there were interactions of theophylline with carboxymethyl chitosan matrix. Further studies on mucociliotoxicity and permeation confirmed that microspheres had better adaptability and high permeation rate. In vitro drug release from the microspheres was not related to the drug/polymer ratios.