反相高效液相色谱法快速分析紫脲酸

为了给咖啡因生产中的亚硝化反应、还原工艺提供准确的中间体检测数据,寻找紫脲酸含量快速分析方法,利用反相高效液相色谱法,通过进行紫脲酸样品波长选择实验、系统适用性实验、定量摸索实验、精密度实验、线性实验,确定了检测波长和紫脲酸样品质量浓度与样品峰面积之间的线性关系。在15.80~188.60mg/L范围内,紫脲酸样品质量浓度与样品峰面积之间的线性方程为y=71.785x,相关系数R2=0.999 8,表明紫脲酸样品质量浓度与样品峰面积之间具有良好的线性关系。使用反相高效液相色谱法能准确、快速检测紫脲酸样品含量,及时对还原反应进行过程监控。     

超重力技术在6-APA生产过程中的应用研究

针对超重力技术在直通法6-APA生产过程中的应用,研究了进料温度、气液比、电机频率、真空度等条件对醋酸丁酯脱除效果的影响。结果表明,超重力技术可以用于脱酯工艺,在保证脱酯液质量的同时,使相关产品收率有所提高。     

中国高速铁路的发展历程与展望

铁路运输历来都与国民经济建设息息相关。所谓高速铁路,通常是指最高运行时速在200公里以上的铁路。历经百十年的技术改革,高速铁路作为一个新型经济产业直接决定着一个国家的基础建设,特别是对于地域广袤的中国。短短十几年,中国实现了从步入高铁时代到引领世界高铁发展的一个大飞跃。高铁对于城市交通的改善作用明显,改变了人们的出行方式,调整了城市民众的出行次数及城市空间结构。     

中国省际城镇职工工资收入分布演进的时空特征

运用Kernel密度估计方法和空间马尔科夫链分析方法,并将空间因素纳入分析框架中,对1978—2009年期间中国省际城镇职工工资收入分布演进的时空特征进行了分析。研究结果表明:从时间动态性看,中国省际城镇职工工资收入的差距正逐步固化和深化,多俱乐部收敛特征明显、贫困陷阱问题日益突出;从空间动态性看,近邻效应对省际城镇职工工资收入分布演进存在一定影响,多数省份的工资收入水平向邻区的平均工资收入水平演进。     

论高速切削加工技术及应用

高速切削加工技术因其具有高效、高精度、工序简化等优点而广泛应用于汽车、航空航天、模具等行业,为提高企业的生产效率和经济效益作出了积极贡献.文章通过分析高速切削加工的关键技术和应用,展望高速切削加工技术的发展前景.     

Workplace values and beliefs: an empirical study of ideology,high commitment management and unionisation

This study is unique in that it examines both managers' and workers' values and beliefs about employment relationships. It found that managers consider the employment relationship in their own workplaces unitarist rather than pluralist, but have mixed ideologies when considering society as a whole. Workers are strongly pluralist when considering society as a whole, but their workplace ideology is somewhat unitarist. A modest union impact on workers' perspectives is found, but little evidence to suggest union's effect commitment to the employing organization. Workers' commitment is to personal careers first and the organization second, while managers put the organization ahead of personal careers. Correlations exist between unitary views of the employment relationship, increased High Commitment Management (HCM) practices, and high levels of commitment. The purpose and contribution of this study is that it reports an assessment of the relation between workplace attitudes and beliefs and the efficacy and influence of management and union initiatives designed to impact them.     

Residential segregation and educational attainment of children from regional migrant families in China

This paper studies the residential segregation effects on educational attainment of children from regional migrant families in China. We find that if migrant families live in segregated communities with fewer local residents, the school dropout rate of the children living with their parents in the host cities is higher and their high school enrollment rate is lower. We employ a unique set of nationwide survey data of regional migrants in China in 2012 and 2013 that comprises more than 150,000 individuals in each year. We first use the ratio of migrants over the total population residing in a community to measure segregation. When the ratio increases by 10%, the school dropout rate of migrant children increases by 4.7% from the mean value. Secondly, we identify segregation from the housing type of the migrant family. When they reside in the dorms provided by their employers or in the workplace, they will also be surrounded by many migrant colleagues. We find that living in such places increases the “not‐going‐to‐high‐school rate” of migrant children by 35% from the mean value. Our subsample analysis indicates that the segregation effects only exist in the samples of male migrant children and rural hukou families.     

The impact of diversity and equality management on firm performance: Beyond high performance work systems

This article demonstrates that a diversity and equality management system (DEMS) contributes to firm performance beyond the effects of a traditional high‐performance work system (HPWS), which consists of bundles of work practices and policies used extensively in high‐performing firms. A DEMS typically includes diversity training and monitoring recruitment, pay, and promotion across minority or other disadvantaged groups. Our analysis of quantitative data from service and manufacturing organizations in Ireland confirms that HPWS practices are associated with positive business performance and finds specifically that DEMS practices are positively associated with higher labor productivity and workforce innovation and lower voluntary employee turnover. © 2010 Wiley Periodicals, Inc.     

高职教育对立统一规律漫谈

高职教育是一种充满矛盾运动和辩证意味的教育类型,高职教育理论中的诸多命题呈现出明显的对立统一特征。用唯物辩证法的立场、观点和方法去解读和阐释高职教育的性质与内涵,揭示对立统一规律在高职教育领域的表现形态与作用机理,是高职教育解决自身面临的理论与实践问题、确立自身品格的必然选择。