非离子表面活性剂增敏催化动力学光度法测定痕量铁

研究了在硫酸介质中,以非离子表面活性剂吐温-80为增敏剂,Fe(III)催化过氧化氢氧化罗丹明B的褪色反应,以此建立了催化动力学光度法测定痕量铁。结果表明,Fe(III)的质量浓度在0~16μg/L范围内服从比尔定律,摩尔吸光系数为1.06×105 L.mol-.1cm-1。该法用于茶叶中痕量铁的分析,结果满意。     

纤痕量钒的催化光度法测定研究

在磷酸介质中,钒(V)强烈的催化溴酸钾氧化钙指示剂褪色的指示反应,研究了该催化反应的最佳实验条件,建立了测定钒的新方法。方法的测定范围是0～100pg/ml,检出限为2.36pg/ml。催化反应的表观活化能为44.91kJ/mol,表观速率常数为1.45×10-3 s-1。方法用于水样中痕量钒的测定,结果满意。     

石墨炉原子吸收法测定钢铁中的痕量铋

钢中痕量铋一般认为是钢中的有害杂质,与铅、锡、砷、锑被称为钢中的"五害".准确测定这些痕量杂质是合金分析的一个重要课题.石墨炉原子吸收具有灵敏度高,选择性好的特点,是当前痕量分析的重要手段之一.我们利用(日立)Z-2000赛曼原子吸收分光光度计,经试验拟定了测定二类钢中痕量铋的分析方法,测量范围是:0.0000×～0.01%.用标准样品对照分析,结果令人满意.方法精密度考核结果为在RSD<3%.     

关于分光光度法的三点新看法

提出关于分光光度法的三个新观点:朗伯-比尔定律作为分光光度法的理论不够严密,它是机械平面波在均匀媒质中传播吸收的规律;分光光度法的实验基础是化学物质对单色光的选择吸收,这种吸收的特点是吸收体系对任一可吸收波段的单色光都必然有一个吸收灵敏度最大区间Ls,在此区间内,吸光度的改变量△Ap正比于体系(bc)的改变量△(bc)p,即△Ap=k△(bc)p;分光光度法的精密度Pt和其它测定一样,等于0.66R.     

钼蓝光度法测定矿物中的二氧化硅

未聚合的硅酸与钼酸铵在0.1mol/L左右的酸性介质中生成黄色的硅钼杂多酸H8[Si(MO2O7)6],又称硅钼黄。但硅钼黄不稳定,加入乙醇后可增加它的稳定性。在0.6-1.0mol/L酸性溶液中,用适量的还原剂将硅钼黄还原为硅钼蓝,进行硅的光度法测定。这样既提高了测量的灵敏度,也使测试的溶液更稳定,利于光度法测定。本法测定二氧化硅含量的范围是0.1%～5%。     

微晶石蜡固相萃取后光度法测定汞

建立应用微晶石蜡作为固相萃取剂分离富集溶液中痕量Hg（Ⅱ）后,光度法测定溶液中Hg（Ⅱ）含量的方法。该方式较为简单、快速、选择性好,且整个萃取操作安全、无毒,应用到水样中Hg（Ⅱ）回收率可达到100%,RSD为5.26%,准确度和精密度较高,效果较为理想。此项目的研究有其实际意义和应用前景。     

分光光度法测定夏枯草中的熊果酸含量

建立分光光度法测定夏枯草中熊果酸的方法：将夏枯草取物首先采用石油醚除杂、活性碳脱色,然后采用香草醛一冰醋酸法测定熊果酸含量。结果表明：该方法简便快速,灵敏度高,重现性好。     

铬天青S光度法测定铝含量的方法讨论

采用盐酸硝酸溶解试样,用高氯酸发烟盐酸飞铬的方法进行前期处理,铬天青S光度法测定钢铁中铝的含量,该方法与铜铁试剂分离-铬天青S测定的方法比较,所测样品中铝的含量基本一致。该方法操作简便、快速准确、干扰少。     

硫酸铝中游离酸测定方法的改进

硫酸铝中游离酸的测定,GB3151-82标准采用氟化钾掩蔽碱标准溶液直接滴定法,但在试验中发现,采用该法测定游离酸,滴定终点褪色比较严重,且试液混浊,不利于滴定终点观察,误差较大。通过大量对比试验,以氟化钠代替氟化钾掩蔽铁、铝等金属离子,以氢氧化钠标准溶液     

标准溶液浓度对紫外分光光度法测定铁含量的影响研究

紫外分光光度法是测定无水肼中铁含量的常用方法。根据现有标准测定铁含量时,发现待测溶液浓度比标准溶液低1个数量级。为研究标准溶液浓度对铁含量测定的影响,配制了两组不同浓度的标准溶液和待测溶液。测定后发现,浓度范围为0.5~5μg/ml的标准溶液吸光度值测定误差明显低于0.05~0.5μg/ml的标准溶液,吸光度在0.1~1.0的范围内时测量误差较小。高浓度溶液标准曲线的相关系数为0.99984,低浓度的为0.99241,铁含量测定应采用高浓度标准溶液。对待测溶液测定后发现,当待测溶液浓度处于标准溶液范围内时,浓度测定相对误差低于0.032%,反之则高达6.0%。     

A group Multi-Criteria Decision-Making method for water supply choice optimization

In this study, an extension of a group Multi-Criteria Decision-Making (MCDM) method based on the fuzzy ELECTRE III (ELimination Et Choice Translating REality) model is presented for water supply choice optimization. The fuzzy ELECTRE III method is improved by using three credibility definitions - concordance, discordance, and net degrees. Experts' opinions are transformed into triangular fuzzy numbers based on the level of uncertainty associated with quantitative and qualitative criteria. The main priority of this method compared to other existing MCDM is that it is a more effective way of dealing with the uncertainties in projects as the application of the opinions is made based on a group decision. A Case Study of a water supply system for the Gamasiab Basin located in the Kermanshah province of Iran is examined to demonstrate the application of the model. Comparing the introduced method's results with the existing MCDMs, including fuzzy TOPSIS and fuzzy AHP methods, indicated that the new method stands more consistent with the local experts' opinions. Therefore, the proposed method is recommended as the optimal decision-making technique for similar applications of complex water supply engineering projects.     

武钢防城港钢铁基地项目取土场防护治理措施研究

大型填海工程的建设需要大量的回填土方，因此取土场的选择、防护及治理是该类工程水土保持方案重点关注的内容之一，而搞好取土场的恢复治理是减少该类工程施工及运行期水土流失的主要手段。文章通过介绍武钢防城港钢铁项目取土场防护治理措施的设计、研究、分析，总结了大型填海工程建设中取土场的选择原则、工作方法及治理措施，供同类工程设计参考。     

多功能水力控制阀在钢厂供水系统中的应用

介绍了多功能水力控制阀新产品在涟钢动力厂净环水系统的应用以及多功能水力控制阀工作原理,并对应用效果进行分析、评价,介绍了在该单位推广的实践体会。     

CONVERGENCE AND ECONOMIC PERFORMANCE IN GREECE: EVIDENCE AT REGIONAL AND PREFECTURE LEVEL

The purpose of this paper is to test regional convergence and to investigate interregional disparities in terms of per capita income in Greece. The novelty of our study lies in the use of a disaggregated dataset for an extended time period (1971–2003) at two regional levels (NUTS II & NUTS III). Our results indicate that there is β convergence between prefectures but not among regions, while no evidence of σ convergence is found at both regional levels. Also, the GDP geographic concentration and population density have a negative impact on growth, which outweighs the positive growth effect of population geographic concentration and GDP spatial inequality. Thus, policies aiming at the decentralization of economic activity in Greece might enhance growth and regional equality simultaneously. Finally, we do not find economic dualism across geographic areas; however, rich prefectures seem to converge faster than poor ones.     

钢铁企业煤炭采购物流的设计

本文以M钢铁公司为例，较详细研究了煤炭基地选择、水运一次中转、二次中转港口的选择、物流成本的测算及水运煤炭物流线路的设计。     

Corporate Performance in Jordan: A Macro Analysis

Abstract

The aim of this study is to de ter mine and an a lyze cor porate per for mance in Jor dan dur ing the pe riod 1989-1996. Four mod els have been spec i fied to test and an a lyze cor po rate per for mance at the macro level. The find ings have re vealed that earn ing per share (EPS) and stock prices are found to be the better mea sures of cor po rate per formance at the macro level. These mea sures were found to be af fected basi cally by or ga ni za tional vari ables, fol lowed by lead er ship vari ables. The pa per thus chal lenges the view that the poor cor po rate per for mance is at trib uted to en vi ron men tal and man a ge rial vari ables, as these variables were found to have no ma jor ef fect on cor po rate per for mance in Jor dan.     

Water sources and demand in South Western Nigeria: implications for water development planners and scientists

In-depth interviews and personal observations were conducted with 5000 households each in four cities (Lagos, Ibadan, Ife and Ilesa) in South Western Nigeria concerning their household water supply system, water use practices and water demand. Owing to deficiencies in piped water availability, households invest in coping strategies in the form of alternative supplies and storage facilities to supplement piped water.This study revealed that about 30% of respondents have a private piped water connection. Even then, the tap water is available only three times a week on average. This has forced people in the area to invest heavily in the provision of storage tanks of various (up to 5000 litres) capacities for storing tap or rainwater wherever it is available and in the construction of both shallow and deep wells. The computed per capital per day water demand for the study area is about 46 litres. The “coping” strategies have important economic implications for the consumers and thus modelling of water demand should go beyond connection decision. The choice of any particular system for a given usage depends on the perceived attributes of the system. The implications of the results for water planners and water demand modellers are presented in this paper.     

Estimates of the Deterrent Effect of Alternative Execution Methods in the United States: 1978–2000

A bstract .   Using a panel of state-level data over the years 1978–2000, this article examines whether the method by which death penalty states conduct their executions affects the per capita incidence of murder in a differential manner. Several measures of the subjective probability of being executed are developed, taking into account the timing of individual executions. The empirical estimates suggest that the deterrent effect of capital punishment is driven primarily by executions conducted by electrocution. None of the other four methods of execution (lethal injection, gas chamber asphyxiation, hanging, and/or firing squad) are found to have a statistically significant impact on the per capita incidence of murder. These results are robust with respect to the manner in which the subjective probabilities of being executed are defined, whether or not a state has a death penalty law on the books, the removal of state and year fixed effects, controls for state-specific time trends, simultaneous control of all execution methods, and controls for other forms of public deterrence. In addition, it is shown that the negative and statistically significant impact of electrocutions is not driven by the occurrence of a "botched" electrocution during the relevant time period.     

Migration and the Tiebout-Tullock Hypothesis Revisited

This study investigates, using state-level data for the period 2000–2005, the Tiebout hypothesis (as extended by Tullock) of "voting with one's feet." This analysis differs from previous related studies not only in its adoption of more current migration and other data but also in other ways. First, unlike most earlier related studies, it includes a separate measure of the overall cost of living; second, it examines per pupil (rather than per capita) outlays on public primary and secondary education; and third, in addition to property taxes, it also focuses on per capita state income tax burdens. Inclusion of the last of these variables in the analysis is based on studies that have found the existence of a state income tax to have influenced migration patterns and other studies that have found higher state income tax levels to have resulted in reduced per capita income growth over time. Moreover, including both property tax burdens and income tax burdens broadens the scope of the hypothesis. Strong empirical support for the Tiebout-Tullock hypothesis (as interpreted here) is obtained for the study period.     

Why is the hypothetico-deductive (H-D) method in information systems not an H-D method?

The hypothetico-deductive (H-D) method is reported to be common in information systems (IS). In IS, the H-D method is often presented as a Popperian, Hempelian, or natural science method. However, there are many fundamental differences between what Popper or Hempel actually say and what the alleged H-D method per Hempel or per Popper means in IS. To avoid possible misunderstanding and conceptual confusion about the basic philosophical concepts, we explain some of these differences, which are not mentioned in IS literature describing the H-D model. Due to these distinctive differences, the alleged H-D method per Hempel or per Popper in IS cannot be regarded as the H-D model per Hempel or per Popper. Further, the H-D model is sometimes confused with another model in IS, the deductive-nomological (D-N) model of explanations. Confusing the H-D and D-N methods can also produce stagnation in the fundamental methodological thinking in IS. As one example, the H-D model (per Hempel or per Popper) does not require hypotheses to be based on existing theories or literature. As a result, misunderstanding the H-D model in IS may seriously limit new hypothesis or theory development, as the H-D model in the philosophy of science allows guessing and imagination as the source for hypotheses and theories. We argue that although IS research (1) generally does not follow the H-D method (per Hempel or per Popper), and (2) should not follow the H-D method, (3) we can still learn from the H-D method and criticisms of it. To learn from the H-D method, we outline method of hypothesis (MoH) approaches for further discussion. These MoH approaches are not hypothetico-deductive, but hypothetico-inductive-qualitative or hypothetico-inductive-statistical. The former MoH endeavors to be suitable for qualitative research, while the latter is aimed for statistical research in IS.