支撑轴精密成形工艺及模具设计

通过对45号钢支撑轴的工艺性分析,提出热挤压成形方案,基于Deform-3D软件对热挤压成形过程进行有限元仿真,分析行程载荷曲线、金属流动和温度场,并对工艺进行优化、预测模具设计中可能出现的问题。在此基础上,设计了一套支撑轴热挤压成形模具,有效缩短了模具设计周期,为该类零件的成形工艺及模具设计提供了一定的参考。     

金属板材织构在线检测技术的研究进展

综述了金属板材织构在线检测技术的研究进展,介绍了基于X射线衍射技术织构在线检测的原理和方法。着重讨论了基于面探测器织构在线检测技术的基础和应用研究,分析了织构在线检测技术存在的问题。最后,展望了织构在线检测技术的未来。     

Bunch-by-bunch beam size measurement during injection at Shanghai Synchrotron Radiation Facility

Fast beam profile measurement is important in fast beam dynamic behavior investigations. A bunch-bybunch beam size measurement system, which is presently used to measure horizontal profile, has been developed at the Shanghai Synchrotron Radiation Facility(SSRF) and is capable of measuring bunches within a separation of 2 ns.The system is based on a direct-imaging optical system and high-speed photomultiplier array detector. A high-bandwidth linear signal amplifier and acquisition module have also been designed to process bunch-by-bunch multichannel signals from the detector. The software resampling technique and principal component analysis method were developed to obtain the synchronized data and enhance the signal-to-noise ratio. The fast injection of transients was successfully captured and analyzed. Moreover, the bunchby-bunch positions and sizes exhibited strong oscillation after the injection at the horizontal betatron oscillation frequency of the SSRF storage ring, and this demonstrated the bunch-by-bunch measurement capability of our system.     

Ionic Liquid-Assisted Solubilization for Improved Enzymatic Esterification of Phenolic Acids

Lipophilic derivatives of phenolic acids could greatly extend their applications in the lipophilic bio-environment and food processing, therefore, developing an efficient lipophilization reaction system constitutes an interesting topic of biocatalysis. Low solubility of phenolic acids in most enzyme-benign solvents represents the main reason for the inefficiency of enzymatic production of lipophilic phenolic derivatives. This work reports a novel approach to improve Candida antartica lipase B (Novozym 435) catalyzed lipophilization of phenolic acids by means of ionic liquids (IL), trioctylmethylammonium trifluoroacetate (tOMA.TFA) assisted solubilization of the substrate. In this approach, the IL plays two major roles, namely, to dissolve phenolic acids at high concentration so as to create a homogeneous system with another substrate—1-octanol, and to be benign to the enzyme to keep the biocatalyst active; which is proved itself to be a correct strategy as improved conversion and volumetric productivity are obtained. The results showed that dosage of IL (denoted as the volume ratio of 1-octanol/tOMA.TFA), concentration of dihydrocaffeic acid (DHCA) and temperature are the key parameters governing the reaction efficiency. A maximum conversion of DHCA was achieved at the ratio of 1-octanol/tOMA.TFA 12:1 (v/v) (1-octanol/DHCA, 38:1 (mol/mol)). A temperature of 70 °C was correct to obtain optimal conversion of DHCA. Even though the conversion of DHCA was higher at lower concentrations of DHCA, the overall volumetric productivity (reaction rate) was much higher when a high concentration of DHCA (1.6 M) was applied, due to IL-assisted solubilization of DHCA. Remarkable enhancement of the conversions of ferulic and caffeic acids were achieved, when the same reaction approach (tOMA.TFA assisted solubilization) was applied to these two phenolic acids, indicating the general applicability of this novel approach.     

Evaluation across and within collaborative manufacturing networks: a comparison of manufacturers’ interactions and attributes

Evaluation on collaborative manufacturing network (CMN) structure characteristics has important implications for network operations such as production decision-making, product recovery, creating consensus. Several recent studies suggest that augmenting network structure with nodes’ attributes can provide a more fine-grained understanding of the network. However, there have been few studies to provide a systematic understanding of these effects in a CMN at scale. This gap is bridged using an industrial printing machinery CMN data-set collected on a web-based producing and outsourcing service platform. Novel phenomena with respect to both interaction and attribute metrics across and within the CMNs are observed. Moreover, although many studies employ either interaction or attribute data to study the relative roles of manufacturers in a CMN, relatively little is known about the relationship between these two types of data. This study explores this relationship by comparing two defined metrics (i.e. relational capability and node capability), which evaluate the manufacturers’ interactions and attributes, respectively. We examine to what extent the two metrics of manufacturers correlate with each other, and how possible dissimilarities and similarities can be explained based on the collected industrial CMN data-set. The insights thereby provide a better basis for efficient operations decision-making in CMN.     

Production of pulp, ethanol and lignin from sugarcane bagasse by alkali-peracetic acid delignification

A two-stage process for delignification of sugarcane bagasse with alkali and peracetic acid (PAA) to produce of pulp, ethanol and lignin products was reported. By this process, sugarcane bagasse can be converted to high-quality pulp, ethanol and lignin products under mild conditions. The obtained pulp had higher brightness and superior strength properties than corresponding kraft pulp. The pulp was also very easy to digest by cellulase, and well suitable for simultaneous saccharification fermentation (SSF) to produce ethanol. The obtained lignins were characterized by several chemical and instrumental analyses. It was found that PAA lignin had higher oxygen content and lower molecular weight. This process is environment-friendly because no sulfur and chlorine were introduced and less wastewater was let. It also can be easily fulfilled by improving a conventional pulping mill based on the existing equipments.     

Model interpretation of electrochemical impedance spectroscopy and polarization behavior of H2/CO mixture oxidation in polymer electrolyte fuel cells

A mathematical model is proposed based on electrode kinetics analysis for the oxidation of 2% CO+H₂ mixture in polymer electrolyte fuel cells. Successful simulation of the polarization curve and experimental impedance spectra for Pt/C electrode system confirm the validity of the model which shows that the impedance is strongly dependent on electrode potential. With the increase of potential, an inductive behavior will occur. It is believed that the appearance of this inductive pattern can be used as a criterion for the onset of CO oxidation by the coincidence of the potential at which inductive behavior occurs with the ignition potential for CO oxidation. The effects of change of CO oxidation rate constant and CO adsorption equilibrium constant on impedance pattern, as well as on CO surface coverage and Faradaic current are also delineated with the use of the proposed model.     

基于模糊中值的IRFPA自适应盲元检测与补偿

红外焦平面阵列(IRFPA)的盲元既包括因材料与制造工艺的缺陷而导致的固定盲元,也包括因环境温度的漂移而出现的随机盲元.基于场景的盲元检测与补偿算法是去除这两种盲元,提高IRFPA 成像质量的有效手段.针对目前滤波类场景检测算法无法有效区分弱小点目标和随机盲元的缺陷,重点研究了随机盲元的响应特性和噪声特性,并提出了一种基于模糊中值与时域累积的盲元自适应检测与补偿算法.首先利用模糊中值滤波器从场景中提取出潜在的盲元,并通过多帧累积确定固定盲元和随机盲元的正确分布,最后对盲元进行实时补偿.实验结果证明:该算法可以有效地实现对盲元的校正,同时避免对弱小点目标的误判别.     

LNG接收站卸料管道保冷层厚度优化模拟

国内LNG接收站卸料管道保冷层多为组合式保冷,保冷层普遍存在着材料浪费的问题。为此,应用Ansys Workbench(AWE)工作平台分别建立了LNG接收站典型的外径为40 in、10 in(1 in=25.4 mm)卸料管道保冷层传热及优化模型。在满足使用要求及设计标准的前提下,对保冷层组合厚度进行优化模拟,并分析了保冷材料热导率受温度变化影响时,其对管道保冷性能的影响。结果表明:优化后,40 in管道每1 000 m可节省投资156万元,10 in管道每1 000 m可节省投资25.62万元;在设计时,如不考虑保冷层热导率随温度变化而采用平均热导率计算,保冷层厚度设计偏保守。对组合保冷材料交接点处温度及各类输入参数敏感性进行分析后得出结论:优化后管道各类指标性能均满足使用要求;内层保冷材料厚度对总投资及热流密度影响最大,大气温度对交接点处温度影响最大。该优化模拟结果及基于AWE工作平台流程化设计优化方法可为LNG管道保冷设计提供参考。