Optimization of l‐arginine purification from Corynebacterium crenatum fermentation broth

l ‐Arginine has many special physiological and biochemical functions, with wide applications in the food and pharmaceutical industry. Few studies on the purification of l ‐arginine from fermentation broth have been conducted; however, none of them were systematic enough for industrial scale‐up. Therefore, it is necessary to develop a highly efficient and systematic process for the purification of l ‐arginine from fermentation broth. In this study, we screened out a cation exchange resin, D155, having high exchange capacity, high selectivity, and easy elution capacity, and analyzed its adsorption isotherm, thermodynamics, and kinetics using different models. Further, the process parameters of fixed‐bed ion exchange adsorption and elution were optimized, and the penetration curve during the operation was modeled. Based on the fixed‐bed ion‐exchange parameters, a 30‐column continuous ion‐exchange system was designed, and the flow velocity in each zone was optimized. Finally, to obtain a high purity of l ‐arginine, the purification tests were conducted using anion exchange resin 711, and an l ‐arginine yield of 99.1% and purity of 98.5% was obtained. This effective and economical method also provides a promising strategy for separation of other amino acids from the fermentation broth, which is of great significance to the l ‐arginine fermentation industry.     

连续流动-分光光度法测定固体废物中氰化物浸出毒性的研究

建立了一种利用连续流动-分光光度法测定固废中氰化物的浸出毒性的方法,当氰化物浓度在0~200μg/L范围内,校准曲线的相关系数r为0.9998;方法的检出限可以达到0.33μg/L;不同浓度样品测定的相对标准偏差低于2.6%,实际固体废物样品加标回收率为96%~103%,方法精密度良好并且准确度较高;通过实际样品测定结果比对,证明方法与传统国家标准方法测定结果有着较高的吻合度,具有良好的应用前景。     

基于支座反力影响线曲率差分的等截面连续梁损伤识别方法

为了实现仅采用损伤状态信息对等截面连续梁进行损伤识别,通过推导三跨不等跨连续梁在移动荷载作用下的支座反力影响线,发现支座反力影响线求曲率并作差分后的曲线在损伤位置会发生突变,基于该现象提出了一种损伤定位方法,进一步建立了损伤程度计算方法,可对损伤程度进行较精确的定量。通过一三跨连续梁和一四跨连续梁工程实例的仿真分析,证明了支座反力影响线曲率差分指标损伤定位和相应的损伤程度定量方法对等截面连续梁损伤识别具有可行性。     

中国催化重整技术进展

催化重整是将石脑油转化为高辛烷值汽油、芳烃,并副产大量氢气的过程,催化重整技术的进步关系到石油炼制与石油化工行业技术的战略安全与竞争力,因此受到极大重视.本文从催化材料、催化反应活性中心及反应机理、催化重整工艺、催化重整反应和再生动力学、关键设备、工程控制技术等方面阐述了我国在理论研究、工业开发及工业应用方面取得的技术进步和成果,对未来的技术进步途径进行了分析与展望.     

半线性抛物方程的时空有限元方法的误差估计

<正>1引言本文考虑如下半线性抛物方程(?)其中Ω∈R~2.函数f(u):C→C满足:(1)|f(u)|≤c|u|(?)u∈C(Ω)(2)Lipschitz条件,即     

Essential and continuous spectrum of symmetric difference equations

Essential and continuous spectrum of symmetric difference equations have been investigated. It has been shown that the deficiency indices and the existence of these components of the spectrum are determined by the growth conditions of the coefficients. In particular, the deficiency indices are superimposition of those clusters determined by the coefficient growth. Finally, we have proved the neccessary and sufficient conditions for the existence of essential spectrum of selfadjoint subspace extensions using subspace theory and asymtotic summation.     

On the (semi)lattices induced by continuous reducibilities

Continuous reducibilities are a proven tool in Computable Analysis, and have applications in other fields such as Constructive Mathematics or Reverse Mathematics. We study the order‐theoretic properties of several variants of the two most important definitions, and especially introduce suprema for them. The suprema are shown to commutate with several characteristic numbers (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Exact controllability and continuous dependence of fractional neutral integro-differential equations with state-dependent delay

In the present paper, with the help of the resolvent operator and some analytic methods, the exact controllability and continuous dependence are investigated for a fractional neutral integro-differential equations with state-dependent delay. As an application, we also give one example to demonstrate our results.     

On sums of Darboux and nowhere constant continuous functions

We show that the property

(P)

for every Darboux function there exists a continuous nowhere constant function such that is Darboux

follows from the following two propositions:

(A)

for every subset of of cardinality there exists a uniformly continuous function such that ,

(B)

for an arbitrary function whose image contains a non-trivial interval there exists an of cardinality such that the restriction of to is uniformly continuous,

which hold in the iterated perfect set model.