企业生态系统竞争共生战略模型

运用企业生态系统和生态位理论,建立企业生态系统竞争共生战略模型,分析企业从竞争到合作、到竞争共生的平衡条件,为我国企业获取竞争优势提供了新的可操作性思路。     

变压器比率差动校验方法的探讨

在变压器微机保护中,比率差动保护的校验往往成为调试的难点。本文对变压器差动原理和相位补偿进行了总结。并以Y／Y／△-11型三绕组变压器及南瑞RCS978保护为例．从正反两方面对变压器比率差动曲线的校验进行了阐述。     

Protein adsorption on the poly（L-lactic acid） surface modified by chitosan and its derivatives

Surface modification of biomaterials has been adopted over the years to improve their biocompatibility. In this study, aiming to promote hydrophilicity and to introduce natural recognition sites onto poly（L-lactic acid） （PLLA） films, chitosan and its derivatives, carboxymethyl chitosan（CMC） and N-methylene phosphonic chitosan （NPC）, were used to modify the surface of PLLA films by an entrapment method. Radiolabeled （^125I） proteins were used to measure the amount of protein adsorbed to PLLA surfaces. Fibronectin （Fn） was used to study the protein adsorption on the modified PLLA surfaces, including isotherm adsorption and adsorption kinetics of single protein, competitive adsorption of binary proteins system and serum multi-proteins and the desorption behavior in serum solution. The results showed that in the isotherm adsorption, Fn had a larger adsorption capacity on the CS-modified surface at lower concentrations, but had a high adsorption capacity at CMC-modified surface at higher concentrations. In the study of absorption kinetics, Fn had a fastest adsorption equilibrium and a highest equilibrium adsorption capacity at the CS-modified surface, while it was opposite at the PCS-modified surface. When BSA and serum were added, it had the greatest effect on the adsorption of Fn on the PCS-modified surface. After 6 hours soaking in the desorpUon study, Fn had reached desorption equilibrium on all the modified surfaces, which had different effects on the desorption rate and the remaining percentage of Fn.     

A股、红筹股及美国股票市场定价比较

对中国大陆的A股、香港的红筹股和美国市场股票的市净率及其决定因素进行比较分析,判断A股市场是否存在泡沫.通过与美国市场的市净率与净资产报酬率之间的关系进行比较,发现:(1)红筹股公司的市净率略高于美国市场,但红筹股公司的市净率与净资产报酬率的关系曲线的斜率与美国市场相等.(2)相对于红筹股公司和美国上市公司,A股亏损公司的市净率的中位数达到4倍以上,这就是所谓的垃圾股现象.(3)盈利A股公司的市净率远高于红筹股公司和美国上市公司.A股公司的市净率相对于净资产报酬率的斜率,亦远高于红筹股公司和美国上市公司,并且这一现象在小规模公司中更为突出.(4)在控制了年度、交易所、操纵行为和公司规模之后,A股公司市净率与净资产报酬率之间的正相关关系消失了.这一结果表明探纵行为及A股市场浓郁的投机气氛是A股市净率相对于成熟市场高企的主要原因.红筹股与成熟市场的市净率比较接近,红筹股回归在一定程度上能够平抑A股市场可能存在的泡沫.     

容积率对城镇土地价格的影响

容积率是影响城镇土地价格最重要的因素之一,在进行地价评估时一般都要进行容积率修正,但目前确定容积率修正系数的方法存在种种不足.本文根据作者多年的基准地价评估经验,分析容积率对地价的影响规律,建立地价与容积率的关系模型,并进行实证分析,为城镇地价评估工作提供一条思路.     

无级变速器电液控制系统研究

无级变速器(CVT)电液控制系统是无级变速器控制的核心, 文章研究了一种采用高速开关网控制的无级变速器电液控制系统,分析了高速开关阀PWM信号的控制原理和控制方法.进行了无级变速器速比控制试验.试验结果证明,无级变速器电液控制系统能够满足无级变速器实际速比控制的需要.     

县域综合经济竞争力测评与区域发展对策研究——以重庆市为例

县域经济是国民经济的重要组成部分。本文采用因子分析法对县域经济综合竞争力进行了测评,测评结果表明：影响县域经济竞争力的因子是基本经济竞争力因子、创新因子、生活水平竞争力因子和经济增长潜力因子;重庆市区域经济发展综合实力差距显著。本文根据经济综合竞争力排序将重庆市经济空间分为稠密区域、准稠密区域、结构弱化区域和农村区域,提出未来一段时期内重庆市区域经济协调发展的系列对策：采取“域-轴-核”开发模式;加强基础设施的建设,构造人才聚集环境,增强县域经济发展后劲;优化产业结构,构造产业竞争优势;转移剩余劳动力,优化资源配置,缓解渝东北和渝东南环境压力。     

基于结构突变的存货质押融资流动性风险实证研究——以中国东方丝绸市场交易所坯布动产为例

引入非参数ICSS结构变点检测算法,以中国东方丝绸坯布市场为例,研究了存货质物商品市场的结构突变和流动性风险模型,并分析了结构突变、不同持有期、不同风险模型对存货质物的质押率的影响。研究发现:(1)对存货质物进行风险度量时加入流动性风险可以更准确刻画商品市场的总风险,且流动性风险占总风险的比重与持有期限呈反比。(2)存货商品市场的波动性、流动性风险有着显著区制转换特征,且不能忽略。考虑结构突变可以更准确地刻画市场风险、流动性风险,也能更准确地确定合理的动产质物的质押率。     

Analyses of location-price game on networks with stochastic customer behavior and its heuristic algorithm

<正> In this paper,a two-stage model is developed to investigate the location strategy andthe commodity pricing strategy for a retail firm that wants to enter a spatial market with multiplecompetitive facilities,where a competitor firm is already operating as a monopoly with several outlets.Expected market shares are calculated based on the stochastic customer behavior on networks.Theauthors provide a sufficient condition for the existence of equilibrium prices in the price game for thefirst time.The existence and uniqueness of the pure strategy Nash equilibrium price with a specifiedutility function are proved in the subgame.A metaheuristic based on tabu search is proposed tosearch the optimal location-price solution of the model.In addition,the authors provide two numericalexamples to illustrate how to obtain the optimal solution and conduct sensitivity analysis.The analysisshows that the best location decision is robust for the follower firm,price game is more intense whenincomes of consumers are lower or there are more substitution products,and neither chain retail gainsfrom the price competition.     

基于TVFIN的压铸模排溢系统溢流口设计方法

根据真值流推理网络（Ｔｒｕｔｈ－ｖａｌｕｅｄＦｌｏｗＩｎｆｅｒｅｎｃｅＮｅｔｗｏｒｋ，简称ＴＶＦＩＮ）的作用，通过对压铸模排溢系统溢流口截面积Ｓｖ与浇注系统内浇口截面积ＳＧ之比值Ｓｖ／Ｓｃ的模糊推理，进行了溢流口的设计。