管道保温层经济厚度设计探讨

管道结构、保温厚度和材料费用和一直是设计人员所关心的重要内容。保温层过薄,可能会造成热量流失;保温层过厚则会导致保温费用的浪费。经济厚度就是综合考虑管道保温投资和年散热损失费用2个因素,计算出在一定年限内其＂年计算费用＂为最小的保温厚度。管道保温层经济厚度设计有利于降低成本,提高能源的利用效率。     

机械通风冷却塔在2×1 000 MW湿冷机组中的应用研究

为提高火力发电厂的经济性,采用"年费用最小法",对优化后的自然通风冷却塔方案与机械通风冷却塔方案进行了比较,得出机械通风冷却塔的最优方案。分析了机力塔的格数、煤炭价格、机组年利用小时数对工程经济性的影响。研究表明,最佳冷却塔格数为48,煤炭价格低于1 500元/t,和机组年利用小时在5 500h左右时,宜采用机力塔。     

Protein efficiency per unit energy and per unit greenhouse gas emissions: Potential contribution of diet choices to climate change mitigation

The production, transport and processing of food products have significant environmental impacts, some of them related to climate change. This study examined the energy use and greenhouse gas emissions associated with the production and transport to a port in Sweden (wholesale point) of 84 common food items of animal and vegetable origin. Energy use and greenhouse gas (GHG) emissions for food items produced in different countries and using various means of production were compared. The results confirmed that animal-based foods are associated with higher energy use and GHG emissions than plant-based foods, with the exception of vegetables produced in heated greenhouses. Analyses of the nutritional value of the foods to assess the amount of protein delivered to the wholesale point per unit energy used or GHG emitted (protein delivery efficiency) showed that the efficiency was much higher for plant-based foods than for animal-based. Remarkably, the efficiency of delivering plant-based protein increased as the amount of protein in the food increased, while the efficiency of delivering animal-based protein decreased. These results have implications for policies encouraging diets with lower environmental impacts for a growing world population.     

美国电网投资情况分析及其启示

电网是重要的国民经济基础设施,电网投资对保证电网适度超前发展、拉动经济增长有重要作用。介绍了美国电网投资的现状,分析了美国电网投资增长的推动因素及今后的发展趋势,提出了对我国电网建设的相关启示。     

The Influence of Digital Design and IT on Modular Product Architecture

The architecture of a product is the design and specification of inherent subsystems, components, and interfaces between subsystems. Well‐defined interfaces allow the development of standardized subsystems that may be shared across product lines, e.g., technology platforms. Past research shows the benefits of modular product architecture in terms of improving cost of goods through common components and materials as well as improving development time cycles for derivative products. Product architecture does not occur by accident; it must be engineered and implemented. This study explores the impact of digital design and information technology (IT) on the development of modular product architectures. Through an empirical study of 122 firms and follow‐up interviews with several respondents, we study the impact of digital design tools and IT infrastructure on the development of modular product architecture and overall project outcomes. The results indicate that a firm's IT infrastructure has a strong, significant relationship with the development of modular product architecture. The findings also show a strong, positive relationship between the development of modular product architecture and project outcomes. However, in contrast to the common perception that digital design tools enhance R&D productivity and effectiveness, we do not find a significant relationship between digital design tool usage and modular product architecture or overall project outcomes. The findings suggest that digital design tools and their organizational implementation need improvement in up‐front new product development phases.     

Profit efficiency among Bangladeshi rice farmers

Production inefficiency is usually analyzed by its three components—technical, allocative, and scale efficiency. In this study, we provide a direct measure of production efficiency of the Bangladeshi rice farmers using a stochastic profit frontier and inefficiency effects model. The data, which are for 1996, include seven conventional inputs and several other background factors affecting production of modern or high yielding varieties (HYVs) of rice spread across 21 villages in three agro-ecological regions of Bangladesh. The results show that there are high levels of inefficiency in modern rice cultivation. The mean level of profit efficiency is 77% suggesting that an estimated 23% of the profit is lost due to a combination of technical, allocative and scale inefficiency in modern rice production. The efficiency differences are explained largely by infrastructure, soil fertility, experience, extension services, tenancy and share of non-agricultural income.     

MACRS DEPRECIATION WITH A SPREADSHEET FUNCTION: A TEACHING AND PRACTICE NOTE

While Excel? and Quatlro Pro? do not have a function MACRS(cost, class life, year), they do have a variable declining balance function, VDB, that can be used to compute annual MACRS depreciation amounts. A literature search of journals and texts did not find examples using this function nor did it find other shortcut approaches to MACRS calculations. A built-in spreadsheet function is clearly superior to relying on hard coding percentages copied from texts or IRS tables or building tables to calculate MACRS percentages. This article 1) describes the underlying definition of the variable declining balance function (VDB), 2( notes some quirks and errors in other spreadsheet depreciation functions and accompanying explanatory material. 3) shows how VDB can be used to calculate MACRS depreciation, 4) provides an example of its use. and 5) suggests useful further developments.     

Measurement of competitiveness in smallholder livestock systems and emerging policy advocacy: An application to Botswana

Farm level cross sectional data of 556 randomly selected livestock producers were used to investigate the competitiveness of smallholder beef farmers in Botswana. The results show the presence of inefficiency, with about 74% of the variation in actual profit from maximum profit (profit frontier) between farms mainly arising from differences in farmers’ practices rather than random variability. Further the mean profit efficiency level of 0.58 suggests that there is a substantial scope to improve beef profitability in Botswana. Significant profit efficiency drivers include, among others, education, distance to market, herd size, access to information and access to income from crop production. Considering the importance of livestock sector for wealth creation and poverty eradication in the rural areas where poverty is more pronounced, there is a need for appropriate development strategies and policies directed towards addressing these factors. In particular there is need to invest in market infrastructure in order to improve market access, hence profit efficiency of smallholder livestock farmers.     

Assessing the impact of cost optimization based on infrastructure modelling on CO2 emissions

Traditionally, logistics design is driven by a need to reduce costs and improve customer service. Recently, the environmental concerns from transport have been increasingly discussed. The traffic levels and associated energy consumption are influenced by supply chain structure, modal split and vehicle utilization. This paper aims to assess the impact of the traditional cost optimization approach to strategic modelling on overall logistics costs and CO₂ emissions by taking into account the supply chain structure (number of depots) and different freight vehicle utilization ratios (90%, 75% and 60%). The simulation model, based on a European case study from the automotive industry, considers strategic and operational level decisions simultaneously. The analysis shows that the optimum design based on costs does not necessary equate to an optimum solution for CO₂ emissions, therefore there is a need to address economical and environmental objectives explicitly as part of the logistics design.     

论跨国公司模式对我国企业海外拓展的引领作用

概括了跨国公司的运作机理,即企业远离总部,在海外建立生产基地和研发、采购、营销等职能部门。企业基于不同区域的比较优势,将总部、生产基地、职能部门等价值链各环节在不同国家、不同地区进行空间布局,以图最终实现总体利润最大化。指出了当前我国企业以跨国公司模式海外拓展的可行方式,如:布局海外研发机构;设立地区总部或投资性公司;打造全球供应链网络;建设海外工业园等。最后提出了以跨国公司模式推进我国企业海外拓展的政策建议,包括抓好健全法律体系、加强政策创新与企业培育、加大金融支持力度、建立企业海外风险防控体系等。     

Profit Sharing for Increased Training Investments

This article investigates whether paying a profit‐related wage stimulates training investments. The results point to increased worker effort and wage flexibility as two channels through which profit sharing enhances investments in training. While both effects are found for young workers, for older workers, profit sharing mainly affects training investments through greater worker effort. The results suggest that profit sharing can be especially useful for stimulating training among older workers, a growing group in the labour force with a relatively weak labour market position due to a lack of training.     

区域科技基础条件平台构建研究

区域科技基础条件平台的构建，可以更好的发挥公共科技服务在区域自主创新和科技进步中的作用，有利于减少科技资源布局分散和重复建设等问题，将为区域主导产业的发展起到极大的促进作用，可以确保产业在全国同行业中处于领先地位。本文在解析了区域科技基础条件平台建设影响因素的基础上，分析区域科技基础条件平台构建的目标任务和重点工作内容，并探讨相关的保障措施。     

Supercenters,Unionized Labor,and Performance in Food Retail

This study examines the impact of unionized labor on supermarket performance, as measured by profit and sales, accounting for the competitive presence of supercenters. The results confirm prior research that shows that supercenters have negative effects on supermarket performance. Unionized supermarkets generally outperform nonunionized supermarkets. However this effect disappears when accounting for supercenters, largely because unionized stores are less likely to compete with supercenters. I find no evidence for a significant union effect on supermarket performance. The deleterious effects of supercenters are stronger for unionized stores. Unionized supermarkets utilize less full‐time labor and more labor‐saving technology than do nonunionized ones.     

评价中国制造业国际竞争力的实证方法研究--兼与波特指标及产业分类法比较

本文应用内容分析法,对近年来发表在国内权威和核心期刊上有关中国制造业国际竞争力评价的重要实证文献进行了回顾与综述,分析了这些实证研究中存在的问题和可取之处,并就两个关键点进行了探讨一是在进行产业国际竞争力的评价时,应该如何选取方法和指标;二是在对中国制造业的国际竞争力进行实证研究时,应当采用何种产业分类法。经过对产业竞争力四个层次的划分及与波特方法的比较,得出对中国制造业的国际竞争力进行评价的方法结论以产业利润率、全球市场份额和劳动生产率/平均工资率三者为评价指标;用相当于ISIC二分位的国内28个制造业部门进行产业分类。     

物流产业集聚对制造业劳动生产率的影响机理研究——基于空间杜宾模型

本文利用2006~2015年我国30个省份（西藏除外）的面板数据,基于空间杜宾模型分析物流产业集聚对我国制造业劳动生产率的作用及空间溢出效应。结果表明,物流产业集聚、物流劳动生产率、外商直接投资、交通基础设施、地方政府投资等影响因素的直接效应与间接效应的方向与显著性均存在差异性。从总效应来看,物流产业集聚与地方财政支出均显著为正,是制造业劳动生产率提升的重要源泉。外商直接投资显著为负,一定程度上抑制我国制造业劳动生产率的提高。     

模块生产网络价值创新的整合架构研究

本文建立了一个决定模块生产网络价值创新的整合性架构，认为模块生产网络价值创新的基本逻辑．就是网络内部的适应性主体通过组织柔性的专业化分工、互补性合作以实现协同效应．这些协同效应就是模块生产网络价值创新的主要来源。协同效应的实现还有赖于模块生产网络有效的自我治理．主要包括设计规则的可行性、系统竞争策略的有效性和标准竞争策略的合理性。这些治理活动镶嵌在既定的制度背景中，模块生产网络受到不同制度环境的限制．就会有不同的治理行为和不同的价值创新绩效。     

Macroeconomic Conditons and HRM-IR Practice

Although macroeconomic developments may seem removed from the world of micro-level HRM-IR practices, such practices are heavily influenced by the macro economy. Wage and price inflation, for example, are closely related, and the general state of the economy influences decisions on hiring, layoffs, and hours. The labor market's tendency toward periods of extended labor surplus or shortage condition the nature of the employer-employee relationship. Economic circumstances affect the labor relations climate and that climate has a bearing on national productivity trends. Government policy in the future may seek to encourage certain kinds of compensation systems, such as profit sharing, for macro reasons. HRM-IR practitioners, too, may benefit by reconsidering policies which make wages relatively inflexible.     

国有企业就业弱势群体形成原因与治理对策研究——国有企业内部劳动市场的缺陷及其修复

本文通过分析传统体制下国有企业内部劳动力市场运行的低效率对下岗失业人员增多的影响，阐述了在经济转轨过程中国有企业内部劳动力市场的缺陷及其修复机制。文章认为，国有企业所依托的内部劳动力市场上的工资决定和就业政策的制度性特征，是造成目前国有企业就业弱势群体就业困难的内在原因，并提出了牺牲效率为代价而过多地使用被动的失业政策无助于从根本上解决问题。为此，应从修复内部劳动力市场运行机制入手，打通内外部劳动力市场，配套使用主动和被动的失业政策，才是减少国有企业就业弱势群体的根本途径。     

“后配额时代”纺织品服装之路:打造强势自主品牌

进入“后配额时代”,我国纺织品服装有了更广阔的发展空间,但同时还面临新贸易技术壁垒、来自对手的竞争及利润率下降的种种考验,在新的经济环境下打造强势自主品牌是纺织品服装发展的出路。     

京津冀区域经济差异时空特征分析

区域经济一体化发展的前提是区域内各单元发展差异逐渐缩小,因此探究区域经济发展的差异问题对促进区域协调发展具有重要意义。本文首先应用熵权法连续测算了京津冀13个城市2001～2014年经济发展实力综合得分。在此基础上,将指数分析方法和探索性空间数据分析方法相结合,将时间尺度和空间尺度相结合,全面探究了京津冀13个城市区域经济差异的演变过程。结果表明,京津冀地区经过10几年的发展,合理的城市空间结构已基本显现,区域经济一体化已经具备良好的条件,但仍然需要从基础设施、发展优势、空间布局等方面入手,促进京津冀区域经济更快更好发展。