再议国企

时代的浪潮簇拥着形形色色的企业在市场海洋中奋力前行,这就是大浪淘沙。今天,在世人的喋喋不休中,国企又一次站在时代的风口浪尖,面临前所未有的关注和争议,前所未有的挑战和压力。近日,据专业机构统计,已公布或披露年报(预报、快报)的1886家上市公司中,有16家公司的亏损额超过10亿元,有42家公司的业绩下降幅度超过1000%。这其中,一些著名国企的名     

“牛”人“微”语

【2013达沃斯张维迎精彩语录】我更奇怪的是,包括我们总理,还有在座的人,所有人天天盯着当天的GDP数字;现在太多的人,从上到下都在被眼前的东西指挥着走,我们为什么不能够看得更远一点?——@中国经济学人【2013达沃斯张维迎精彩语录】好多人误以为国有企业就是全民的企业,就是老百姓的企业,从来都不是这样,国有企业其实只是有利于少数人,而不是有利于多数人,它破坏了社会的公平,也伤害了社会的道德,腐败只是问题的一个方面,国有企业的负面影响我们一般都看不到,包括人事任命、工作安排等等。     

介绍一种制作简易的硅碳棒接头

硅碳棒接头的好坏,直接影响到管式高温炉的正常工作和硅碳棒的使用寿命。我们试制了一种制作简易的接头。在炉温处于1200～1300℃连续工作的条件下,使用这种硅碳棒接头,不易氧化,不会因跳火而烧坏,接触良好,安全可靠,使用寿命长,效果非常好。 制作方法是:用箱形电阻炉的废电炉丝(直径2mm,材料为Cr15Ni60或Cr20Ni80的合金)三根(两根长400mm左右,另一根长200mm左右。尺寸仅供参考。),首先,在长     

Mn(Ⅱ)-EDTA电位滴定铜的催化指示电极及其应用研究

提出了在氨三乙酸(NTA,活化剂)存在下,以Mn(Ⅱ)催化NaIO4氧化结晶紫的反应指示滴定终点,以自制的结晶紫选择性电极为指示电极,Mn(Ⅱ)为滴定剂,EDTA为阻抑剂,催化滴定测定微量铜的新方法.该方法对试剂用量,酸度,温度,滴定剂浓度,滴定速度及干扰消除等进行了探讨,选择了适宜的实验条件.用于火药中微量铜的测定,样品平均回收率为98.17%,相对标准偏差为1.02%,结果与原子吸收光谱法测定结果相符.     

浅述简笔画在儿童成长中的重要作用

在当今的时代背景下,每个家庭只有一到两个孩子,随着人们生活的日益富足,越来越多的父母开始更加注重孩子的成长与未来,从某种角度上说,孩子的发展质量就预示着家庭的将来。不少年轻的父母＂恨铁不成钢＂,省吃俭用,在孩子身上盲目投资,上各种培训班,学各种专业技能,期待把孩子培养成＂绝世全才＂,但这股一浪高过一浪的风潮中却隐藏着一定的隐患,家长的选择不适合孩子的实际,选择的专业之多让孩子不堪重负,     

氧化镁对高铝渣稳定性影响

 为解决降低成本,拓宽矿源的目的,对高铝矿终渣进行了细致且系统的研究。通过对黏度曲线的测量,动力学活化能的计算,热力学计算的手段,分析炉渣各组分析出规律及其变化,得出结果：炉渣稳定性与成分有较为紧密的关系,各超大型高炉炉渣成分相差不大,但黏度随温度变化规律确是大相径庭;一般来说,超大型高炉高温时炉渣活度差异较小,在160000~170000J,而在低温时活化能的变化率差异较大;高铝低镁渣的稳定性超过高铝高镁渣,如果能够使高炉中的镁降低可以大幅度提高炉料的冶金性能,降低渣量,是降低成本的有效措施;降低终渣中的镁含量不是否定镁对炉渣稀化作用,恰恰相反,提高渣中镁在液相中的作用效率;高铝渣未必就一定不稳定,应适宜调整炉渣其他组分,使高炉适应高铝渣操作。     

全球白银的供求形势

1需求形势据国外媒体报道,2003年全球制造业对白银的需求量已上升到24358t,扭转了前两年连续下降的趋势。同时,白银的市场价格也平均上涨了6%。报道说,由于全球电子工业生产的上升和经济环境的好转,2003年,全球工业应用白银的数量增长了3%,达到9957t。中国2003年的白银消费量达到它空前的高水平,制造业对白银的需求量实际上升8%,工业用银数量达到了782t。报道说,首饰和银制品是消费白银的主要市场。2003年,这方面对白银的需求量增长了4.1%,实际用银用达到了7844t。增长幅度最大的是中国和泰国,中国上升22%,泰国上升13%。具有白银首饰消费传…     

攀长钢万吨钛材生产基地规划

本文介绍了攀钢集团四川长城特殊钢股份有限公司万吨钛材生产线的建设方案,说明了该项目具有国际先进水平的装机水平,具有资源、技术和成本等优势,产品多样化,质量高,具有很强的竞争力.并指出该项目的建设将提高我国钛工业的整体水平,有利于我国的经济建设和国防建设,逐步改变世界钛材生产的格局,提高中国钛材生产的国际地位.     

南非黄金生产现状

据国外媒体报道,2004年,南非的黄金生产降到了1931年以来的最低点——342t/a。从1885年南非矿山协会开始对采矿业建立官方统计以来,每年出口额最大的是黄金。现在,这个状况已经发生了变化,铂族金属的出口额已经超过黄金,占第一位。2004年,南非的矿业生产总额是1250亿兰特,黄金产值占293亿兰特,落后于333亿的铂族金属,居第二位。当年南非煤炭产值是276亿兰特。1970年代,南非的黄金产量是1000t/a,占当年全球矿山新生产的黄金的70%左右,一段时期以来,南非的黄金生产以每年5%的速度萎缩,而且近几年来,由于南非货币兰特处于强势,使这种萎缩的速度…     

浅谈摄影作品中如何科学运用线条和光线

人们常说,画家所面对的挑战,是怎样在一张空白的画纸上,加上一些东西来使它变得有艺术性：而摄影师所面临的挑战则是迥然不同的,他们要从杂乱的环境中,充分运用构图技巧,把其中无关的景物除去,使画面看来具有艺术性。换句话说,作画是从一个空白的画面开始,然后决定把一些东西加进画面内,来表达自己的意念。摄影师所关注的,就是怎样安排现有景物内的元素,借以表达自己的意念。     

巩固循环经济成绩,完善体制机制建设

循环经济强调物质、能量循环利用在时间——空间配置上的可能性和合理性,要求自然资源在不断循环中持久利用。围绕循环经济系统观、经济观、价值观、生产观和消费观,结合金川集团自有矿产资源现状与特点,突出如何高效利用矿产能源资源,总结"十一五"以来资源综合利用与循环经济产业取得的成就,坚持把资源节约放在首位,建议集团公司按照"减量化、再利用、再循环、替代化、产业共生网络化和修补化"原则开展循环经济体系与产业建设,加强政策研究与运用,完善循环经济基础制度和管理体系建设,突出循环经济技术攻关工作,创造有利于循环经济发展的环境,促进矿产资源高效利用。     

熔炼次数对M17返回料合金成分、组织和性能的影响

实验结果表明,M17铸造高温合金(%:0.16C、8.79Cr、5.79A1、4.93Ti、3.29Mo、15.20Co、0.78V、0.015B、0.073Zr、0.002S、0.001P、0.001 1O、0.001 0N)经25 kg真空感应炉返回重熔后,Si含量随重熔次数的增加而略有增加,合金中主要元素和其它杂质元素S、P、H的含量变化不大,而氧、氮略有增加;合金中初生碳化物由新合金中的草书体逐渐向返回合金块状转变,初生碳化物的遗传性堵塞合金凝固时的补缩通道,使返回料合金的疏松倾向增大,高温塑性下降较大。     

80t低频气保恒熔速电渣炉的技术特点及应用

为满足中国能源(电站、核电)、轴承、模具、航天等领域对高端锻件的需求,提升国产高端锻件的市场竞争力,实现中信重工在高洁净、高品质钢锭制造领域的又一新突破,在经过多年对国内外先进电渣装备调研、考察、论证的基础上,新增一台80t低频单电极气保全同轴恒熔速电渣炉。该电渣炉采用了低频电源、单电极、全同轴、微正压惰性气体保护、高精度称重、恒熔速、同相逆并联大电流短网、双炉头车、电网平衡等多项创新技术,可实现重熔过程计算机自动控制,具有设计独特、技术含量高、节能环保、安全可靠等优点。生产的电渣锭经过质量检测分析,电渣锭偏析程度小、纯净度高,质量达到较高水平。     

Leaching Behavior of Lead, Chromium (III), and Zinc in Cement/Metal Oxides Systems

This paper reports the study of the leaching behavior of cement/metal oxides mixtures containing lead, chromium (III) and zinc oxides. A fractional factorial design of experiments (24?1) was carried out considering four factors, the concentration of ZnO, Cr2O3, PbO, and Fe2O3 in the formulations. Iron oxide was also included in the experimental design as it is usually the main constituent of industrial wastes from thermal processes, where lead, chromium and zinc oxides are also found. After 56 days of curing, samples were subjected to the Acid Neutralization Capacity Test and the concentrations of Cr, Zn, and Pb were determined in the leachate at different pH after filtering. The output variables for the analysis of the experimental data were the concentration of metals at initial pH (in water), at pH 9, 7, and 4, and the acid neutralization capacity of the samples at pH 9. The analysis of the results indicates that the immobilization of Zn and Pb in Portland cement is poor; these metals behave as their amphoteric hydroxides. However, the leaching of Cr (III) is in the range found in the control sample, indicating that the stabilization of Cr (III) is successful.     

电感耦合等离子体原子发射光谱法测定锰铁合金、锰硅合金和金属锰中8种微量元素

锰铁合金、锰硅合金、金属锰中铅、砷、钛、铜、镍、钙、镁、铝的含量决定了产品质量,以往常采用化学法或原子吸收光谱法进行测定,但存在准确度较差或测定速度不能满足要求等问题。为了实现上述元素的准确、快速测定,建立了采用电感耦合等离子体原子发射光谱法(ICP-AES)测定锰铁合金、锰硅合金和金属锰中微量铅、砷、钛、铜、镍、钙、镁、铝的方法。实验以硝酸、盐酸、氢氟酸、高氯酸分解样品,并使硅与氢氟酸反应生成四氟化硅挥发除去,试液中剩余共存元素主要有铁、锰等。实验结果表明,铁不干扰测定,通过在标准溶液系列中进行锰基体匹配消除锰基体效应的影响。以2mL高氯酸和6mL盐酸混合酸(8%)作为分析介质,可以达到最佳分析效果。在各元素校准曲线线性范围内,线性相关系数在0.9992~0.9999之间;方法中各元素的检出限在0.0001~0.0040μg/mL。实验方法用于测定锰铁合金、锰硅合金、金属锰中铅、砷、钛、铜、镍、钙、镁、铝,结果的相对标准偏差(RSD,n=11)在2.2%~9.4%;回收率在95%~105%;选择7个实验室进行了验证试验,各实验室间结果基本一致;按照实验方法测定了4个标准样品(材字-32、YSB C 28618、YSB C 26605)中铅、砷、钛、铜、镍、钙、镁、铝,结果与认定值相吻合。     

Development Model for Competitive Construction Industry in the People’s Republic of China

This paper identifies and analyzes the open-policy trend of the Chinese construction industry, which is characterized by trade liberalization, the underlying principle of the World Trade Organization (WTO). Compared to the construction industries in the United States, Japan, and the U.K., the construction industry in China is less developed in its legal framework, industrial structure, technological level, and international market share. To develop a competitive construction industry, the Chinese construction industry needs not only to accommodate appropriate international practice, but also to adapt and adopt it according to the market environment in China. A model to enhance the performance of the Chinese construction industry is proposed. The model consists of six modules: defining government’s role, opening up the construction market and establishing a competitive mechanism, promoting design institutes’ services and empowering professional bodies, encouraging technological innovations, upgrading employees’ educational level, and adopting multiprocurement routes. Recognizing China’s recent accession to the WTO and the attendant boost to its economy and industry development, the paper gives a timely evaluation of the post-WTO Chinese construction industry and proposes a model for its development. The model may serve the needs of academics, Chinese construction policymakers, construction enterprises, design institutes, and foreign contractors.     

矿热炉自动配料控制系统设计

针对矿热炉配料系统工艺流程复杂、可靠性及性价比要求高的特点,系统利用Modbus通信和工业以太网技术构建了由上位监控层、下位控制层和现场设备层组成的总体网络架构,设计出以S7-1200PLC为核心的稳定、高效和经济实用的分布式控制系统。通过合理的硬件、软件和监控界面设计,有效解决了生产效率与配料精度之间的矛盾,实现了称量、配料自动化。该系统自投入使用以来,性能稳定,工作可靠,具有较高的性价比,能够满足实际生产需求,达到了预期设计的目标。     

Closed-Form Model and Parametric Study on Connection of Concrete-Filled FRP Tubes to Concrete Footings by Direct Embedment

Concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) have been introduced as a new system for piles, columns, and poles. A simple moment connection based on direct embedment of the CFFT into concrete footings or pile caps, without using dowel-bar reinforcement, has been proposed by the authors. Robust analytical models to predict the critical embedment length (Xcr) were also developed and experimentally validated. In this paper, a comprehensive parametric study is carried out using the models developed earlier along with a newly developed closed-form model for the general case of axial loading, bending, and shear applied to the CFFT member. The parameters studied are the diameter (D), thickness (t), length outside the footing (L), and laminate structure of the FRP tube, as well as the tube-concrete interface bond strength (τmax?), concrete compressive strength in the CFFT (fct′) and footing (fc′), and the magnitude and eccentricity of axial compressive or tensile loads. It was shown that increasing D, L/D, τmax?, and fc′ of the footing, or the axial compression load, reduces (X/D)cr, whereas increasing t and fct′ of the CFFT, the fraction of longitudinal fibers in the tube, or the axial tension load, increases Xcr. As the axial load eccentricity increases, Xcr reduces for tension loads and increases for compression loads until both cases converge asymptotically to the same Xcr value, essentially that of pure bending.     

Fall Cone Test to Characterize Shear Strength of Organic Sediments

In this paper, the results of the standard percussion cup test, the penetration cone test, and the laboratory vane test performed on organic sediments and kaolin are discussed. First, the relationship between the water content and the cone penetration depth is explored. Second, the relationship between the shear strength, using the laboratory vane apparatus, and the water content is investigated. Finally, the relationship between the shear strength and the penetration depth of the cone, at different levels of water content, is explored.     

Measuring students' connectedness to school, teachers, and family: Validation of three scales.

Connectedness to school, teachers, and family are all significant protective factors in adolescents' lives, yet the measurement of each varies considerably. This article describes the measurement properties of three composite scales of adolescent connectedness, adapted from the Add Health study and the California Healthy Kids Survey. These composite scales are created by either summing or taking the mean of all individual items, measured on an ordinal scale. This approach fails to account for the ordinal, non-normal nature of the data. Using a covariance approach, this article describes the measurement properties of the latent constructs of connectedness to school, teachers, and family and the contribution of each of the items used to compile the relevant composite score. The outcomes of this study will provide researchers and practitioners with information about the validity, reliability, and overall usefulness of each of the measures of adolescents' perception of their connectedness to school, teachers, and family. (PsycINFO Database Record (c) 2010 APA, all rights reserved)