Thermal runaway prevention in catalytic packed bed reactor by solid temperature measurement and Control

Magnetic crystallite thermometry has been used to measure the average nickel crystallite temperature in packed bed reactors during ethane hydrogenolysis, an exothermic reaction. The technique is based on the temperature dependence of the magnetic moment of dispersed nickel catalysts. Measurement of the average catalyst temperature is very useful for reactor control because of its shorter time constant compared with exit fluid temperature. Bed temperature control based on the exit fluid temperature, which has often been used as a control variable, is too slow to protect thermal runaway of the bed. The advantage of short time constant by measuring the average catalyst temperature has been incorporated with enhanced feedback control system to control the bed temperature and prevent the thermal runaway of the catalyst bed. An enhanced feedback control structure with supervisory action performed better than the classical proportional-integral control in runaway prevention when the two control schemes were compared with each other on the basis of the trippoint (incipient thermal runaway).     

"再听证"条款考疑

介绍了日本、韩国及我国台湾地区的行政程序法关于再次举行听证会的规定.分析了我国行政程序法试拟稿及部分地方立法中有关于再听证规定存在的问题,并提出了具体的修改意见.     

Application of open-pit and underground mining technology for residual coal of end slopes

Given the conditions of residual coal from the boundary of a flat dipping open-pit mine,which uses strip areas mining and inner dumping with slope-covering,we propose an open-pit and underground integrated mining technology for residual coal of end slopes.In the proposal a conveyance road and ventilation conveyance near the slope are built,corresponding to the pit mining area and the surface coal mine dump,as well as an interval haulage tunnel and air-inlet tunnel.The outcome shows that such mining method may reduce the effect to slope stability from underground mining,it does not affect the dumping advance and has a high recovery rate of residual coal resources.The working face is timbered by single hydraulic props,transported by a scraper conveyor and supported by coal walls.This method of mining is one of layered top coal caving,with high resource recovery,low production cost where positive economic benefit can be realized.     

基于广东区域性高职院校创业教育的思考——记广州城建职业学院学生创业教育的探索

职业素质是劳动者对社会职业了解与适应能力的一种综合体现,主要包括职业修养和职业技能。在高职院校中开展创业教育是我国经济形势发展的需要,对于培养学生的实践能力、创新精神和解决学生的就业压力有着十分重要的意义。广州城建职业学院的创业教育可以从以下三方面着手：一是转变观念,营造氛围;二是传授本领,打好基础;三是开展活动,提高能力,逐步探索出一条适合广州城建职业学院特色高职学生创业教育的新路子。     

生活质量视阈下的大学生“精神贫困”测量指标研究

高校大学生＂精神贫困＂现象已引起人们重视,成为多方关注话题。本文在梳理前人研究成果基础上,对＂精神贫困＂测量指标进行研究,以获得科学的测量指标体系,为获得真实科学的一手资料打进行理论论证。     

A power-aware code-compression design for RISC/VLIW architecture

We studied the architecture of embedded computing systems from the viewpoint of power consumption in memory systems and used a selective-code-compression (SCC) approach to realize our design.Based on t...     

Renewal strategies for old industrial areas in the post-industrial age—Take “Zurich-West” in Switzerland as an example

This paper introduces and analyses the renewal planning of “Zurich-West”, an old industrial area. It points out that systematic and comprehensive target orientation, extensive collaboration in argumentation and decision-making, and the design ideas of coexistence and integration are the key to its success. Considering the status quo of China’s old industrial district remodeling, the paper offers some suggestions. Supported by the National Natural Science Foundation of China (Grant No. 50878045)     

A model for studying LCAT reaction: In vitro cholesterol esterification in pig ovarian follicular fluid

Phosphatidylcholine acyltransferase (lecithin:cholesterol acyltransferase or LCAT; EC 2.3.1.43) activity was found to be present in pig ovarian follicular fluid (POFF), in addition to pig serum (PS). The cholesterol esterification rate in both POFF and PS is linear with incubation time up to 2 hr. The mean absolute rate of POFF-cholesterol esterification was 8.1±0.4 nmoles per ml per hr approximately one-fourth of that in PS. However, the fractional rate (percent of labeled cholesterol esterified per hr) of POFF-cholesterol esterification was similar to that observed in PS. There was little variation of absolute rate of cholesterol esterification in the fluid obtained from different sizes of follicles. Fatty acid or triacylglycerol did not participate in the reaction of cholesterol esterification in POFF. No appreciable change in enzymatic activity was found from storing POFF at 4 C for periods of time up to 24 hr or at −70 C up to 2 months, but activity was lost thereafter. On the other hand, PS showed a much longer period of stability (5 days at 4 C and 9 months at −70 C). A discrepancy between the fatty acid composition of cholesteryl esters formed by the LCAT reaction and the fatty acid composition at the C-2 position of phosphatidylcholine led us to propose a two-step mechanism for the LCAT reaction. It is concluded that the LCAT of POFF, as well as that of plasma, is specific for individual fatty acids rather than for the fatty acid composition of phosphatidylcholine. The fatty acid concentration of lysophosphatidylcholine decreased during prolonged incubation times (6 to 21 hr) suggesting that the increased lysophosphatidylcholine formed as a product of the LCAT reaction may be reused as substrate for the LCAT reaction or for hydrolysis by lysophosphatidylcholine hydrolase. Presented at the AOCS Meeting, New York, May 1977.     

化学铣切槽液中Na2S的分析

本文采用“碘量法”测定化铣液中的硫化钠，分析结果的准确度和精密度完全能够满足生产要求。     

Infrared reflectance and transmission spectra of semiconducting non-stoichiometric CdGe x As2

The infrared reflectance and transmission spectra of amorphous CdGe _x As₂ were investigated to study the amorphous structure with varying Ge content. The mid-infrared optical absorption edges of amorphous CdGe _x As₂ with 0<x<1.2, were observed in the range 1.6–1.7 m, indicating a structural similarity in short-range order throughout. Comparing the reflectance and transmission spectra of amorphous and devitrified crystalline phases established that the structures of amorphous CdGe _x As₂ transformed from the CdAs₂ basic structure to the chalcopyrite (CdGeAs₂) structure, as one progressed fromx=0 tox=1.2. The infrared spectra were interpreted interactively with radial distribution function, magnetic susceptibility, density measurements, and crystallization studies. The crystallization behaviour of amorphous CdGe _x As₂ that was heat treated at different temperatures was investigated using far-infrared transmission spectra.