Science Letters:A new configuration of membrane stack for retrieval of nickel absorbed in resins

A new configuration integrated ion exchange effect with both electro-migration and electrochemical reaction in a single cell was developed to effectively retrieve metal ions from simulated wastewater using ion exchange resins without additive chemicals. By simply assembling cation exchange resins and anion exchange resins separated by homogeneous membranes, we found that the system will always be acidic in the concentrate compartment so that ion exchange resins could be in-situ regenerated without hydroxide precipitation. Such a realizable design will be really suitable for wastewater purification.     

镍对小麦幼苗叶片抗氧化酶活性的影响

采用营养液水培,研究了不同浓度（5﹑10﹑20﹑50﹑100、130 mg·L-1）镍处理对小麦幼苗叶片SOD、POD、CAT和APX活性的影响.结果表明,各浓度镍处理均抑制了小麦幼苗叶片SOD活性,而小麦幼苗叶片POD、CAT和APX活性在较低浓度镍处理下升高,在较高浓度镍处理下降低.     

基于分块颜色和形状的图像检索方法

图像的单一特征只能代表图像的某一方面的信息,其应用范围受到限制.本文在分析图像颜色和形状特征的基础上,根据各自的特点,提出了一种新的基于分决颜色和形状的图像检索方法.首先,在图像分块的基础上提取图像的颜色和特征点;其次,根据特征点提取图像的形状信息;最后,以颜色和形状作为综合特征,采用相应的匹配算法进行图像检索.实验证明,该方法不仅准确度高,而且还可应用于基于对象或区域的图像查询.     

新型疏水性咪唑类手性离子液体的合成

该文采用（R）-1-苯基乙胺为原料合成了一种新型疏水性咪唑类手性离子液体,并通过熔点、IR、NMR等技术进行了结构确证.所采用的合成方案简单且易于控制.     

Rapid dechlorination of chlorinated organic compounds by nickel/iron bimetallic system in water

Detoxification of chlorinated organic compounds via reaction with nickel/iron powder was implemented in aqueous solution. Compared to iron, nickel/iron bimetallic powder had higher hydrodechlorination activities for both atrazine (ATR) and p-chlorophenol (pCP); nickel/iron (2.96%, w/w) was shown to have the largest specific surface area and the optimum proportion for the dechlorination of both ATR and pCP. Electrochemical measurements showed that the adsorbed hydrogen atom on the nickel must have been the dominant reductive agent for the dechlorination of both ATR andpCP in this system.     

离子交换分离富集极谱法测定地质样品中的钌

采用离子交换树脂富集钌，钌的吸附率达98％以上。将树脂灰化，用极谱法测定，可以测定5ng／g的钌。标样分析结果与标准值吻合。     

A new local ablation for unresectable primary liver tumor： effect of electrothermal and electrochemical therapy on rat liver

Background： Electrochemical therapy （ECT） has been used to treat unresectable hepatic tumor. In order to improve its efficacy, we combined ECT with hyperthermia induced by electrothermal needle （ETN） （ETECT）. The aim of this study is to investigate the destructive effect of ETECT on normal rat liver. Methods： Twenty rats were randomized into 4 treatment groups （n=5 in each group）： control, ECT alone, hyperthermia alone and ETECT. Following the treatment, sections of the livers were histologically examined by light microscopy and the destructive volumes were measured with micrometer. Results： We found that the destructive volumes in ETECT group were the largest （P〈0.01）. In ETECT group coagulative necrosis was found in both anode and cathode areas, around which transition zones existed. The transition zones can only be seen when coulomb was increased in ECT group. Conclusion： ETECT was demonstrated to enhance the destructive effect of ECT. This study provides theoretical and experimental basis for a new local ablative treatment for unresectable primary liver tumor.     

庆大霉素发酵液的分离提取

建立从发酵液中提取庆大霉素的方法,获得具有一定纯度的庆大霉素分析样品。采用732阳离子交换树脂,利用离子交换法从发酵液中提取庆大霉素,探讨不同条件对庆大霉素收率的影响。确定最优的提取条件为:发酵液pH2～3,吸附时间2 h,解吸剂浓度5%,解吸剂流速0.4 mL/min。经HPLC测定,发酵液通过离子交换法分离提取后,庆大霉素纯度由50.7%提高到92.5%。离子交换法适用于庆大霉素发酵液的分离提取,提取液纯度达到药物分析的要求。     

离子交换层析分离核苷酸的实验方法

对传统的离子交换层析分离单核苷酸实验方法进行改革和创新。以强碱型阴离子交换树脂、采用梯度洗脱和阶段洗脱对酵母RNA水解液进行分离,利用标准核苷酸的参数确定层析峰的核苷酸种类。不但可以使学生全面掌握离子交换层析技术,而且经过对标准核苷酸性质的研究及核苷酸的鉴定,还可将原有实验内容从一个简单的分离纯化实验提升为研究性实验,从而有效调动了学生的学习兴趣和学习热情,明显提高了学生的综合实验能力。     

广谱高效杀菌剂过氧乙酸的合成工艺研究

研究了以A型阳离子交换树脂和硫酸为混合催化剂合成过氧乙酸的工艺.实验结果表明:在室温(25℃)下,n (冰醋酸)∶n (双氧水)=2∶1,A型阳离子交换树脂和浓硫酸的用量分别为总质量的1.5%～2.0%和10%,搅拌4h,过氧乙酸产率可达18.8%,加入0.1%～0.2%(质量分数)焦磷酸钠,产品的稳定性提高 10%～20%.     

日本财政政策效果下降的新探析

详细分析财政理论的发展过程以及在开放条件下,财政政策、货币政策与国际收支均衡目标的关系,并且利用模型具体分析日本20世纪90年代的财政政策效果,可以发现日本的财政政策效果,随着前提条件的放宽,特别是开放条件下,受资本自由流动及浮动汇率的影响,呈逐渐下降的趋势。     

高校文献检索课在线自导式教学模式研究

分析了基于网络的文献检索课在线自导武教学模式的优势,借鉴国外网络教学经验。探讨了文献检索课网上教学的主要形式以及实施在线自导式教学模式应注意的关键问题。     

浅析高等院校图书馆文献需求

从文献学科结构、读者需求信息和文献利用情况、出版物市场情况和文献出版信息三方面分析了高等院校图书馆文献需求,以提高文献采访工作的针对性,最终形成文献价值和文献需要有机统一的文献体系。     

实验室制备酚醛树脂条件的探讨

探讨了实验室制备酚醛树脂的最佳条件,简述了制取过程中的注意事项.     

无线移动数字图书馆系统中多媒体检索的同步模式

1IntroductionRecent advances in wireless communication,digitallibrary,distributed multi media,massive storage,andmobile computing technologies are sti mulating the de-velopment of mobile multi media digital library systems(M2DLS)that allow mobile clients to access multi me-dia material anywhere and anyti me over a cellular ra-dio network[1,2].In M2DLS,multi media objects,ingeneral,can be composed of multiple media streamssuch as audio and video,whose retrieval must proceedso as to not only …     

扩大中国汇率浮动区间的设想

入世后，随着中国经济的开放度的增加，汇率将在各种经济变量中逐渐居于核心地位，这是因为开放经济中的各种变量的状况最终都将在汇率上得到不同程度的体现，而汇率的调整又会对从外部到内部，从宏观到微观的各个方面、各个层次对开放经济的运行产生深刻的影响，而我国现行的汇率制度事实上较难适应这种要求，主要在于有管理的浮动汇率实际上是固定汇率，在国内经济的基本面存在缺陷而又不能在短期内、有实质性的改变的前提下，以我国近2千亿美元的外汇储备面对与脱离实体经济运行每天达2万多亿美元的国际游资，根本不能有效保卫这种固定汇率，故应扩大汇率浮动区间，采用有管理的浮动汇率-有一定幅度的目标区浮动汇率制。     

环境与组织因素组态效应对新创企业绩效的影响——基于模糊集的定性比较分析

基于组态理论,探讨影响不同新创企业间绩效差异的多重并发因素和因果复杂机制。利用模糊集定性比较分析方法对237个样本企业进行分析,深入探究由环境层面的2个条件与组织层面的3个条件组成的不同组态与新创企业绩效之间的关系。研究发现:①高创业机会识别、高创业拼凑和高创业学习都是新创企业产生高绩效的必要条件,缺乏高创业机会识别、缺乏高创业拼凑是非高绩效产生的必要条件;②新创企业产生高绩效的驱动机制分为4条路径并概括为3种构型模式;③抑制新创企业绩效水平的路径和促进绩效的路径具有非对称性的特征。     

离子树脂循环交换法生产硫酸钾工艺计算

本文介绍了离子树脂循环交换法生产硫酸钾工艺设计计算方法,可用于工艺、设备设计和指导生产管理.     

新时期地方院校对外交流与合作初探

全球化浪潮给地方高校对外交流与合作发展带来了挑战,也带来了机遇。本文简要阐述了地方高校对外交流与合作现状,并分析了地方院校对外交流与合作存在的问题,针对当前形势和存在的问题为新时期地方院校对外交流合作的发展提出了新思路。     

Polychronicity: review of the literature and a new configuration for the study of this hidden dimension of online learning

Polychronicity is the natural tendency or preference for structuring time that has an influence on people’s behaviors. Highly polychronic individuals are involved in everything, doing many things at once because they value human relationships and interactions over arbitrary schedules and appointments. In contrast, highly monochronic individuals focus on one thing at a time, perceive other events as interruptions, and stress a high degree of scheduling, and promptness in meeting obligations and attending appointments. Although time is an important variable in educational contexts, and in particular in online learning, there is a lack of studies on polychronicity in educational research. This article reviews, summarizes, and extends the literature on polychronicity conceptualization and assessment; it discusses the limitations of the results and offers a multidimensional proposal for a polychronicity construct. Finally, the implications of students’ time differences and their impact on instructional situations are discussed.