长城铁矿最佳生产规模分析论证

本文在对拟扩建的长城铁矿调整生产规模的必要性和可行性进行分析的基础上,根据经济盈利性分析原则,以长城铁矿为例,对矿山扩大生产规模的方法进行了探讨,并用盈利曲线法对长城铁矿最佳生产规模进行了分析论证。     

知识产品生产机制探析

知识产品的原创生产分为前后两个阶段:隐性知识的创造和隐性知识的脑外物化表达,其在运行上呈现出一种精神变物质-物质还原为精神的随机循环往复、彼此互动的机制。虽然单个知识产品的生产具有不确定性,其投入与产出之间是一种随机概率关系,但就知识产品社会再生产的连续过程来看,则表现为一种不规则的梯级增长。与此相适应,知识产品生产具有边际成本递减和边际收益递增机制。除此之外,知识产品的生产还具有创造性、个体性和路径依赖性三个突出的特点。     

一种镀锌板生产线电气传动控制系统

介绍了镀锌板生产线的工艺流程及其对电气传动的要求，采用PLC对镀锌板生产线的张力和带速进行协调控制，对电气传动控制系统的活套带重补偿和控制算法作了论述。本系统在实际使用中可靠性高，经济效益好，是一种适用的镀锌板生产线电气传动控制系统。     

基于GASA算法的提前或拖期问题优化

针对企业生产的提前 /拖期问题,提出了提前 /拖期问题的数学模型,在此基础上,利用GASA混合优化策略优化之,既保留了传统遗传算法能很快达到最优值领域的优点,又通过结合模拟退火算法大大改善传统遗传算法在后期的收敛性。     

风险投资与孵化器结合初探

建立孵化器，是促进科技成果转化、培育科技型中小企业的有效途径,是被实践证明了的加速高新技术产业化的重要经验，也是建设国家创新体系的重要组成部分。对孵化器和风险投资结合的初步研究，可以更好地把两相融合，更好地培育科技型中小企业，从而加速高新技术产业化进程。     

Are gold,USD, and Bitcoin hedge or safe haven against stock? The implication for risk management

This study investigates whether gold, USD, and Bitcoin are hedge and safe haven assets against stock and if they are useful in diversifying downside risk for international stock markets. We propose a combined GO-GARCH-EVT-copula approach to examine the hedge and safe haven properties of gold, USD, and Bitcoin. We then examine the attractiveness of these assets in reducing stock portfolio risk by using downside risk measures estimated by the proposed approach and other competing models. We also evaluate the relative performance of the proposed model in reducing downside risk with the competing models. The findings of the study indicate that the USD is the most valuable hedge and safe haven asset closely followed by gold, while Bitcoin is the least valuable. It is also observed that the proposed combined approach performs best in reducing the portfolio downside risk. The findings of this study are of significance for portfolio managers and individual investors who wish to protect the portfolio value during market turmoil.     

美国金融业对外直接投资流向的实证分析

美国1995年～2000年金融业对外直接投资流向分布极不均衡,对投资流向分布进行统计分析发现,非金融领域直接投资、1994年金融业对外直接投资存量、双边贸易量、东道国经济金融发展水平是金融业对外直接投资的主要决定因素,证明了邓宁国际生产折衷主义理论对金融业对外直接投资的解释力。据此简要分析美国对中国金融领域直接投资现状,并分析了今后发展趋势。     

Wood Fuel or Carbon Sink? Aspects of Forestry in the Climate Question

This paper discusses and contrasts two mainroles of forestry in light of the debate on theglobal climate. As the main problem is relatedto the increases of the CO₂-concentrationin the atmosphere, forests may be viewed aspart of the alleviation of the problem throughtheir function as (i) a source of biomass forenergy production, which may replace fossilfuels and thus indirectly reduceCO₂-emissions, and as (ii) carbon storage,since a growing forest extracts atmosphericCO₂ and fixes it as carbon in biomass. Inthe Scandinavian forestry, logging residues areincreasingly being used for energy production.In this paper the value of forests as a sourceof bioenergy is added to the traditional timbervalue. Formulated as a joint production modelwithin the Faustmann framework, the effect ofthis addition on the optimal rotation length isdiscussed. Based on data for spruce, thedominant species in the Scandinavian forestry,it is demonstrated that the rotation length isshortened compared to the standard Faustmannmodel. Shorter rotation length implies lesscarbon storage. Therefore, in this modelwithout explicit regard to the social carbonstorage value of the forest, the gains in termsof the climate problem from utilisation offorest biomass for energy production are beingdiminished by the value of reduced carbonstorage. The carbon value of the forest is thenadded to complete the model, with the effect ofincreasing the rotation length, a result thatis well known in the literature. Finally, theempirical effects of the interaction of thesetwo climate-related value elements of theforest are discussed.     

先进制造技术与生产流程的协同性研究

制造系统的有效性需要通过先进制造技术与生产流程的合理匹配来体现。在分析各种先进制造技术与生产流程相互关系的基础上,提出了协同度的概念,并给出了其计算方法。     

中国粮食生产区域分化特征和成因的实证研究

对中国在1990年和2002年粮食生产的区域分化状况进行统计分析的结果表明,工业化和城市化的发展,以及农产品市场形成条件下,稻米生产的区域分散特征、小麦生产的区域集中特征以及玉米播种面积的集中和生产产量的分散特征日益明显。计量检验显示,人均承包经营耕地面积和种植业收入比率是影响粮食生产区域分化的最主要的两个因素。