高氯废水中低化学需氧量的快速检测研究

在高氯废水低化学需氧量的检测中,常用的检测方法有微波消解法、快速消解分光光度法与氯气校正法等。文章将快速消解分光光度法做为研究对象,对其进行改进处理,进一步提高高氯废水中低化学需氧量的检测速率与检测精度,为工业废水的测定提供更高效的方法。     

浅谈自配试剂快速COD比色法与重铬酸盐法的比较的优势

化学需氧量CODcr是指在一定条件下，用强氧化剂处理水样时所消耗氧化剂的量，反映了水中受还原性物质污染的程度【2】。目前用于测定化学需氧量的方法较多，最常见和多用的是快速CODcr比色法与仲裁方法----重铬酸盐法。而重铬酸盐法存在时间长、安全性差、能耗大、药品用量大等缺点，而快速CODcr比色法所用的哈希固定药剂成本高，因而采用自配试剂代替哈希试剂进行CODcr的测定。这样，与重铬酸盐法比较，在时间上、能耗上以及成本上都有很大的节约，在安全上更是远超于重铬酸盐法。     

分光光度法测定化学需氧量的探讨

化学需氧量作为一个能量化表示水质污染程度的重要指标,在废水分析中占有重要的地位,也理所当然的成为了实验分析的重点。本文对分光光度法测定化学需氧量的测量条件和影响因素进行了探讨,使得化学需氧量测量结果更为准确,操作更简便、快捷。     

重铬酸盐法测定化学需氧量的不确定度评定

化学需氧量是一种表示水中还原性物质多少的重要指标,能够比较精确显示污水中共有多少有机物。化学需氧量数值越大,水体的污染情况越严重,是有关部门评估水质污染情况的一个重要综合指标。文章针对重铬酸盐法测定化学需氧量的不确定度评定进行了分析探讨。     

使用准确化学需氧量COD光谱监测仪确保水质质量

化学需氧量COD是水被有机物污染程度的重要指标,水质污染影响到生活、生产的质量。介绍了化学需氧量COD检测仪校准方法,化学需氧量（COD）去除方法及减排措施建议。     

基于金属氧化物复合电极快速测定地表水COD方法的研究

本文基于新研发的一种新型金属氧化物电极的化学需氧量(COD)测定技术,并应用于地表水COD的快速检测。该技术是以金属钛为模板,电沉积法制备了金属氧化物复合电极(Ti/Sb-SnO_2/PbO_2),并以其为工作电极,安培法测定水体的化学需氧量。采用扫描电镜(SEM)对电极进行了表征。以葡萄糖为样品,优化了复合电极的测量电位(1.35 V),电解液硫酸钠浓度(20mM)。在最优检测条件下,COD浓度与响应电流之间呈良好的线性关系,线性范围1-175 mg/L,相关系数R=0.9991,最低检出限为0.3 mg/L。对15个大连市重要水库及河流水功能区限制纳污考核断面的实际水样进行测定,结果令人满意。     

高锰酸盐指数与化学需氧量的相关性分析及应用

通过对高锰酸盐指数与化学需氧量监测数据的相关性分析,表明高锰酸盐指数与化学需氧量线性关系显著。因此在水体还原性污染物构成相对稳定的情况下,通过高锰酸盐指数推算出化学需氧量,对水质监测工作有一定的应用价值。     

关于单箱卷烟化学需氧量的问题分析与优化

该文阐述了化学需氧量高对生态的影响,并结合四川中烟绵阳卷烟厂生产工作实际,对卷烟生产过程中产生的单箱化学需氧量(COD)排放量波动大等问题原因进行了分析,提出了优化方法。     

连续流动注射分析仪在测定地表水主要参数指标中的应用

文章采用AA3连续流动注射分析仪,建立了同时测定地表水中总氮、总磷、六价铬和化学需氧量的分析方法。实验结果表明:通过连续流动注射测定总氮、总磷、六价铬和化学需氧量的标准曲线相关性良好,同时该方法具有良好的精密度和准确度。通过流动注射和国家标准方法同时对实际水样中总氮、总磷、六价铬和化学需氧量进行测定,其结果无明显差异。     

重铬酸钾法测定水中化学需氧量的不确定度评定

文章立足实际,对重铬酸钾法测定水中化学需氧量的不确定度评定方法进行研究。阐述化学需氧量检测方法原理,而后分别从数学模型、不确定度的来源、输入量的标准不确定度评定方面,详细解析了不确定度的评定方式。     

生化需氧量快速测定法的应用与分析

通过生化需氧量快速测定法与五日生化法的比较,以及现场应用与分析,在生物膜保养、样品分析过程、仪器日常维护保养等方面找出了确保快速测定法数据准确性的关键技术,大大提升了测定速率,为环境突发事件的快速处理提供了参考。     

The effects of ownership structure on conditions at the top: The case of CEO pay raises

We examine how ownership configuration affects the determination of CEO pay raises. Based on a sample of 188 firms over a 5-year period, it was found that pay raises were based on distinctly different factors, depending on the ownership profile of the firm. In management-controlled firms—where no single major owner exists—results suggest an overarching pay philosophy: maximize CEO pay, subject to demonstration of face legitimacy of that pay. In externally-controlled firms—where a major (nonmanager) owner exists—results suggest a very different philosophy: minimize CEO pay, subject to the ability to attract/retain a satisfactory CEO.     

3,3′,5,5′-四甲基联苯胺比色法测定饮用水中余氯

针对采用GB/T 5750.11—2006生活饮用水标准检验方法中的3,3′,5,5′-四甲基联苯胺目视比色法检测余氯时出现的问题,探讨了四甲基联苯胺配制的介质浓度及配制方法,以及pH值、温度、显色时间、显色剂用量等因素对测定过程的影响,改进了生活饮用水中余氯的测定方法。     

一种新型的原生XML数据库系统的实现和应用探讨

原生XML数据库是随着XML语言的迅速发展而产生的一种非关系型数据库系统。介绍了一种基于Java技术的原生XML数据库实验系统SoapStore,并对其性能优化和实际应用等方面进行了分析和讨论。     

How Does Market Making Affect Industrial Relations? Evidence from Eight German Hospitals

The introduction of market mechanisms matters for industrial relations. In the German hospital sector, national liberalization policies have put immense pressure on local management and worker representatives and led to the growth of a low‐wage sector. In case studies of eight hospitals, we find some locales where market making has led to union revitalization and mobilization, but this effect varies. Using an eight‐way comparison, we infer a configuration of three aspects of the local political economy — labour markets, politics and co‐determination rules — that together provide a well‐fitting explanation for both variation and change.     

萃取光度法直接测定矿石中钽

介绍了一个不需分离直接测定矿石中钽的方法。样品经过氧化钠分解,选择最佳试验条件,基于钽与孔雀绿萃取显色进行测定,方法快捷、简便,具有实用性。     

The status and prospects for genetically modified crops in Europe

Despite the rapid expansion in the global area planted with genetically modified (GM) crops, there has been resistance to this technology in Europe: this article considers why. Molecular technologies used to produce GM crops are reviewed and crops currently and soon to become available listed. It is argued that the prospects for GM crops depend on: (1) consumer acceptance — which depends on the perception of the benefits GM crops offer and on confidence in the legislative framework and regulatory procedures designed to identify and quantify any potential disadvantages; (2) further technological advances — which might reduce any adverse consequences of and enhance the benefits from GM crops; (3) patent law — which underpins incentives for private investment and largely determines the development of market structure; and (4) the relative profitability of GM crops vis à vis conventionally bred varieties — which will be a key determinant of the area planted. Importantly, regulations which increase consumer confidence may also raise the costs of planting GM crops and therefore will act to reduce the area planted.     

The Effect of "Front-Loading" Problem-Solving on Product Development Performance

In recent years, there has been a growing interest in the link between problem‐solving capabilities and product development performance. In this article, the authors apply a problem‐solving perspective to the management of product development and suggest how shifting the identification and solving of problems—a concept that they define as front‐loading—can reduce development time and cost and thus free up resources to be more innovative in the marketplace. The authors develop a framework of front‐loading problem‐solving and present related examples and case evidence from development practice. These examples include Boeing's and Chrysler's experience with the use of “digital mock‐ups” to identify interference problems that are very costly to solve if identified further downstream—sometimes as late as during or—after first full‐scale assembly. In the article, the authors propose that front‐loading can be achieved using a number of different approaches, two of which are discussed in detail: (1) project‐to‐project knowledge transfer—leverage previous projects by transferring problem and solution‐specific information to new projects; and (2) rapid problem‐solving—leverage advanced technologies and methods to increase the overall rate at which development problems are identified and solved. Methods for improving project‐to‐project knowledge transfer include the effective use of “postmortems,” which are records of post‐project learning and thus can be instrumental in carrying forward the knowledge from current and past projects. As the article suggests, rapid problem‐solving can be achieved by optimally combining new technologies (such as computer simulation) that allow for faster problem‐solving cycles with traditional technologies (such as late stage prototypes), which usually provide higher fidelity. A field study of front‐loading at Toyota Motor Corporation shows how a systematic effort to front‐load its development process has, in effect, shifted problem‐identification and problem‐solving to earlier stages of product development. They conclude the article with a discussion of other approaches to front‐load problem‐solving in product development and propose how a problem‐solving perspective can help managers to build capabilities for higher development performance.     

Toward a Model of New Product Preannouncement Timing

For products and services ranging from software to the latest motion picture, the use of new product preannouncements (NPPAs) has become commonplace. In the weeks and months (and perhaps years) before the release of a new product, a company may share information with various groups, including customers, competitors, and producers of complementary products. These prelaunch communications serve various purposes—for example, building interest for the new product, obtaining feedback from customers, or encouraging consumers to delay purchases until the new product becomes available. Despite the key role that NPPAs play in the successful release of new products, however, almost no research has been conducted to explore the proper timing for such communications. Bryan Lilly and Rockney Walters provide a starting point for these investigations, by describing the elements of an NPPA and presenting a model of the factors that influence NPPA timing. Drawing on existing research and interviews with managers from firms in a wide range of industries, they offer insights into the nature and the timing of NPPAs, and they provide recommendations for improving the effectiveness of NPPAs. Their conceptual model lists four sets of factors that affect NPPA timing: expected reactions of competitors; product-related factors, such as the product's complexity and innovativeness; buyer-related factors, such as the length of the buying process; and firm-related factors, including final determination of the product's feature set. The relative strength of these effects depends on the objectives and the audience for the NPPA. For example, a late NPPA—that is, one close to the product's release date—effectively shields a new product from rapid competitive responses. On the other hand, an early NPPA allows channel members and customers to gain familiarity with complex or innovative products. Their findings suggest that early NPPAs are most appropriate for complex or highly innovative products as well as those that carry high, but avoidable switching costs for buyers. Late NPPAs are recommended if the firm expects sales of the new product to cannibalize those of existing products. Late NPPAs are also appropriate if a product's feature set is not yet frozen. To improve the effectiveness of NPPAs, managers must clearly define their objectives and carefully match the timing and the content of the NPPA to the target audience.     

Evaluating traditional share—Price and residual demand measures of market power in the catsup industry

In this paper we specify a price determination model which can test both the traditional positive interbrand price—share hypothesis and the negative intrabrand relationship predicted by residual demand analysis. We evaluate this relationship empirically using three-dimensional panel data from the catsup industry. We find support for both hypothesized relationships, and conclude that market power exists in this industry. Further, we conclude that the results depend critically on the characteristics of the data set to be analyzed.