论生态经济系统稳态

本文论述了生态经济系统非平衡稳定态的概念、特性及其实现的途径。指出生态经济系统稳态,是非平衡的,对外全面开放、激烈竞争、充分利用涨落作用,对内协同、有序、自组织、自适应、自催化、且有非线性作用和支配性、良性运转、进展演替的耗散结构状态。生态经济系统平衡的提法应被生态经济系统稳态的概念所取代。     

浅谈集邮业务的个性化服务

文章回顾了我国集邮业务的历史演变和发展状况,分析了集邮业务的业务结构变化及其所带来的经营方式和经营策略的变化,提出个性化服务是集邮业务的发展方向,论述了个性化服务的社会需求、市场前景和发展空间,探讨了个性化服务的发展措施及经营思路。     

Pricing options using implied trees: Evidence from FTSE‐100 options

Previously, few, if any, comparative tests of performance of Jackwerth's ( 1997 ) generalized binomial tree (GBT) and Derman and Kani ( 1994 ) implied volatility tree (IVT) models were done. In this paper, we propose five different weight functions in GBT and test them empirically compared to both the Black‐Scholes model and IVT. We use the daily settlement prices of FTSE‐100 index options from January to November 1999. With both American and European options traded on the FTSE‐100 index, we construct both GBT and IVT from European options and examine their performance in both the hedging of European option and the pricing of its American counterpart. IVT is found to produce least hedging errors and best results for American call options with earlier maturity than the maturity span of the implied trees. GBT appears to produce better results for American ATM put pricing for any maturity, and better in‐sample fit for options with maturity equal to the maturity span of the implied trees. Deltas calculated from IVT are consistently lower (higher) than Black‐Scholes deltas for both European and American calls (puts) in absolute term. The reverse holds true for GBT deltas. These empirical findings about the relative performance of GBT, IVT, and Standard Black‐Scholes models are important to practitioners as they indicate that different methods should be used for different applications, and some cautions should be exercised. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:601–626, 2002     

晶化时间对CoAPO-11分子筛合成过程中转晶的影响

本文研究了晶化时间对低钴含量(x=0.1)的CoAPO-11分子筛合成过程中转晶现象的影响,并采用XRD、SEM对产物进行表征。结果表明,200℃下晶化48 h,可获得纯相CoAPO-11;当晶化时间超过48 h时,产物便开始向[Co-Al-P-O]-GIS型分子筛转化;晶化延长至72 h时,产物已全部转化为[Co-Al-P-O]-GIS型分子筛,该转化过程不可逆。从分子筛骨架结构单元出发,阐述了转晶现象的内在影响因素。     

“以大代小”火力发电企业的价值评估

在火力发电行业进行“以大代小”技改工程后,为了解决“一厂多制”的问题,需要对完成“以大代小”技改项目后所产生的新发电企业进行价值评估。在评估过程中,应明确价值类型,充分考虑租赁的资产、委托运行维护管理等要素对企业价值的影响。本文对大型火电发电机组的生命周期进行了分析,并在此基础上提出了对“以大代小”新火力发电企业进行收益测算的“三阶段测算模型”。     

农村劳动力转移模型:基于中国制度背景的构造

本文在对经典的农村劳动力流动模型进行理论梳理的基础上,引入中国的制度变量,试图构建适合中国制度背景的农村劳动力转移模型,同时,运用经验事实对其作进一步的实证检验,并分析了模型的政策含义。     

对俄边境贸易外汇管理中的难点及对策

俄罗斯是我国周边国家中经济贸易总量最大、综合国力最强的国家.我们应该利用中侬两国经济的互补性,抓住时机,大力发展两国贸易及经济合作,抢占俄罗斯市场,为中国经济的发展及对外贸易注入新的活力.人总行应加强同俄罗斯央行的联系,协调两国银行间的合作.应由口岸城市的中俄双方银行建立互设或单设美元帐户,直接通汇、结算.应通过银行结算的现钞贸易,享受国家出口商品退税政策,调动创汇积极性.建议调整增加预付款额度.