华东聚丙烯产品竞争浅析

聚丙烯产品是重要的生产生活资料,华东区域是我国重要的聚丙烯产品生产与消费区域.目前国内与国外聚丙烯装置新建与扩建项目大量落成并投入生产,国内外聚丙烯产能迅速增长,国内聚丙烯产业竞争环境正在由垄断向垄断竞争转变.作者描述了目前华东区域的聚丙烯产品供求概况,对产业内外环境加以分析,并进一步依照聚丙烯应用的大类阐述了其目前的...     

Photocatalytic degradation of two volatile fatty acids in monocomponent and multicomponent systems: Comparison between batch and annular photoreactors

This study investigates the influence of the inlet concentrations on the degradation rates of a binary mixture of volatile fatty acids (propionic and butyric acids). TiO₂-coated non-woven fibre textile was used as the photocatalyst in a batch reactor and in an annular reactor at laminar flow regime. The humidity level, temperature, UV intensity and flow rate were kept constant. First, the adsorption isotherms were determined and these showed that the propionic acid is less adsorbed than the butyric acid onto the catalyst. Conversely to the adsorption, the photodegradation of pure propionic acid is better than the degradation of pure butyric acid. Photodegradation is greatly inhibited when the two acids are mixed in comparison to the pure compounds. The propionic acid is more affected. This inhibition is attributed to the competitive adsorption of the two species on the active sites of the catalyst. A model which takes into account the competitive adsorption is proposed in order to determine the outlet concentrations of the compounds knowing the inlet concentrations in the annular reactor.     

竞争抑制ELISA法检测霍乱灭活疫苗中脂多糖的含量

目的采用竞争抑制ELISA法检测霍乱灭活疫苗中脂多糖(Lipopolysaccharide,LPS)的含量,以替代小鼠免疫力试验方法。方法用竞争抑制ELISA法检测霍乱灭活疫苗中LPS的含量,并分析与小鼠免疫力试验检测结果的一致性。结果霍乱灭活疫苗中LPS的含量与疫苗保护力呈正相关。结论采用竞争抑制ELISA法检测霍乱灭活疫苗中LPS的含量,能够反映疫苗的保护力,为进一步替代小鼠免疫力试验方法奠定了基础。     

发挥整体优势提高乙烯装置竞争力

从上下游资源配置、炼-化一体化、联副产品整体综合利用及工艺技术开发等几个方面，对如何提高中国石油乙烯装置竞争力进行了初步的探讨。     

实施绩效分析提高乙烯装置竞争力

扬子乙烯绩效分析项目是在所罗门公司派遣专家的协助下，以扬子乙烯装置为核心，寻找该装置在工艺、计划、设备检维修、财务及行政管理等诸方面与世界同类先进装置的差距，分析原因并共同制定一系列改进措施，按步骤、按次序地进行实施，从而不断缩短、进而消除与世界先进水平存在的差距，提高扬子乙烯技术管理水平和装置竞争力。     

Mathematical programming and game theory optimization-based tool for supply chain planning in cooperative/competitive environments

This work proposes to improve the tactical decision-making of a supply chain (SC) under an uncertain competition scenario through the use of different optimization criteria, which allows to manage not only the specific objectives of the SC of interest, but also the way how its clients address their selection between different potential suppliers, identifying best market share for the SC of interest and the strategy to attain it. The resulting multi-objective optimization problem has been solved using the ?-constraint method in order to approximate the Pareto space of non-dominated solutions while a framework based on game theory is used as a reactive decision making support tool to deal with the uncertainty of the competitive scenario. The use of the proposed system is illustrated through its application to a multi-product, multi-echelon supply chain case study, which is intended to cooperate or to compete with another SC of similar characteristics.     

Adsorption equilibria between dye and surfactant in single and binary systems onto geological materials

Adsorption characteristics of cationic dyes and surfactants onto clay and sandstone from a single component system were studied using toluidine blue (TB) and cetyl trimethylammonium bromide (CTAB). Equilibrium data of TB and CTAB in the single solute systems fit well to the Langmuir and the Freundlich adsorption isotherms. Competitive adsorption was observed between dye and surfactant cations. The effect of sodium chloride on dye and surfactant adsorption was studied in TB–NaCl and CTAB–NaCl binary systems. Equilibrium adsorption for binary systems was analyzed by using the extended Langmuir and the extended Freundlich models. Adsorption results for the TB–CTAB system onto both adsorbents were also well described by the Sheindorf–Rebuhn–Sheintuch (SRS) model for multi-component systems. Free energy changes for adsorption systems were calculated using thermodynamic equilibrium constants evaluated from selectivity coefficients of the binary systems. The site distribution functions estimated using Freundlich model parameters gave valuable information about the ratio of the adsorption sites on adsorbent surface having different affinity for competing cations.     

Triglyceride selectivity of immobilized <Emphasis Type="Italic">Thermomyces lanuginosa</Emphasis> lipase in interesterification

The triglyceride (fatty acid) selectivity of an immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) was investigated in lipase-catalyzed interesterification reactions between two nono-acid TG in n-hexane. Tristearin (tri-C18∶0) was used as a reference in a series of TG with saturated FA from tri-C4∶0 to tri-C20∶0, except for tri-C6∶0, and in a series of unsaturated FA from tri-C18∶1 to tri-C18∶3. The quantification was performed by HPLC, and different methods of selectivity evaluation were used. None of the methods used showed any significant differences between the performances of the lipase on the different TG, indicating that Lipozyme TL IM is nonselective toward FA or TG in the system used. A response surface design was used to investigate the influence of water activities (a _w ) and reaction temperatures on the reactivity of Lipozyme TL IM with a system of tripalmitin (tri-C16∶0) and trilaurin (tri-C12∶0) in n-hexane. An increase in temperature (40 to 60°C) was found to affect the reactivity of the lipase significantly. The reactivity of Lipozyme TL IM was unaffected by the change in a _w from 0.1130 to 0.5289. An increase in a _w only led to an increase in FFA formation.     

Theoretical analysis of inhibition effect on steady states of enzymatic membrane reactor with substrate and product retention for reaction producing weak acid

The aim of this study is to formulate a model of enzymatic membrane reactor (EMR), i.e., a continuous, stirred tank bioreactor with full enzyme recycle, for a reaction producing a weak acid, and to explore the effect of substrate and product inhibition of different mechanisms coupled with transport properties of the membrane on the static behaviour of the system. The inhibition of an enzyme by a substrate leads to the non-monotonicity of reaction rate expression with respect to the substrate concentration. If a product of enzymatic reaction, taking place in the EMR, influences the pH of a reaction mixture this is also the factor causing the non-monotonicity of the substrate and product dependent reaction rate. The character of these dependencies affects substantially the structure of the steady states of the reactor. The bifurcation diagrams, shown in the work, are of different characters depending on the bifurcation parameter. It has been found, that bifurcation diagrams for competitive and uncompetitive inhibition by a substrate differ in the number and position of bifurcation points. Steady states of multiplicity five have been localised in case of uncompetitive inhibition by the substrate at high affinity of the enzyme to this substrate. Retention of reagents, related to transport properties of a membrane, influences significantly the effectiveness of a process. A specially written software in Delphi™ has been used for the calculations.     

优化规划不断提高上海化学工业区的竞争力

通过回顾上海化学工业区十余年的开发建设,阐述了"一体化"集成开发的规划理念及在开发建设过程中规划优化的原则和重要性,强调规划是提升化工区竞争力的重要抓手.