基于进度优化的大型项目激励机制模型

在项目管理实践中,业主通常会设立激励机制以确保项目按期完成,而承包商则会根据业主设定的激励机制合理安排项目进度.本文讨论了大型项目的激励机制,研究了业主和承包商的决策问题,建立了以项目收益净现值最大化为目标函数的Stackelberg主从递阶决策模型.通过各子项目激励强度的设定对激励机制进行优化,协调业主和各承包商的利益关系,进而实现业主收益的最大化.     

The role of orientation experiments in discovering mechanisms

Many types of experiments have been recognized in the literature. One important type we discuss in this article is the orientation experiment. While orientation experiments are like other types of experiments in that they are tests for causal relevance, they also have other qualities. One important (but not the only) goal of these experiments is to offer a rough, qualitative characterization of the mechanism responsible for a capacity of interest, effectively constraining future research. This makes them particularly useful during the early stages of investigation, when an explanandum-phenomenon has just been identified and several (often competing) hypotheses as to the qualitative character of the mechanism responsible for it are proposed. We illustrate our claims, and explicate a number of additional aims that orientation experiments can sometimes serve, by considering three case studies from different era's, namely the discovery of the mechanisms responsible for i) the capacity of eels to produce numbing sensations (17th and 18th century), ii) puerperal fever in Semmelweis' Vienna Maternity Hospital (19th century), and iii) the capacity of pigeons to home (20th century).     

Natural diversity: A neo-essentialist misconstrual of homeostatic property cluster theory in natural kind debates

In natural kind debates, Boyd's famous Homeostatic Property Cluster theory (HPC) is often misconstrued in two ways: Not only is it thought to make for a normative standard for natural kinds, but also to require the homeostatic mechanisms underlying nomological property clusters to be uniform. My argument for the illegitimacy of both overgeneralizations, both on systematic as well as exegetical grounds, is based on the misconstrued view's failure to account for functional kinds in science. I illustrate the combination of these two misconstruals with recent entries into the natural kind debate about emotions. Finally, I examine and reject Stich's “Kornblith-Devitt method” as a potential justification of these misconstruals.     

Setal diversity,trophic modes and functional morphology of feeding appendages of two callianassid shrimps,Callichirus major and Sergio mirim (Decapoda: Thalassinidea: Callianassidae)

In the present study we investigate the trophic behaviour, stomach content and morphology of the feeding appendages, with emphasis on setae, of two callianassids; a generalist feeder, Callichirus major (Say, 1818) and a strict deposit feeder, Sergio mirim (Rodrigues, 1971). Of the 87 setal types described, only 5% were common to both species. Setal types were clustered in four main categories; plumed, serrate, plumodenticulate and simple. Callichirus major has higher setal diversity than S. mirim. Relative to the amount of setal types present in each species, C. major has a higher ratio of serrate to plumodenticulate setal types and similar percentages of plumed and simple setae. Examining the setae and spatial position of the segments of the feeding appendages, it is possible to infer that the main function of the dactyli, propodi and basal endites is to brush particles, while the meri, ischia and coxal endites retain sediment. The setal diversity found on the feeding appendages reflected the diverse trophic strategies of the callianassid species studied. Exclusive deposit feeders, e.g. S. mirim, appear to have fewer setal types than generalist feeders, e.g. C. major. Apparently, the higher ratio of serrate to plumodenticulate setal types in Callianassidae depends more on the necessity to triturate particles prior to ingestion than on the trophic mechanism used by the species.     

试论嵩山地区亮甲山组白云岩和燧石的成因

本文应用野外和室内相结合的研究方法,对篙山地区亮甲山组白云岩和燧石的成因进行了探索。白云岩中燧石的产状有纹层状、树丛状、斑状、结核状及团块状等。室内岩石薄片、扫描电子显微镜及阴极发光显微镜等研究表明,该组原始沉积的CaCO_3沉积物及早期形成的石灰岩曾先后遭受了初次云化、初次硅化、二次云化及二次硅化作用的改造才形成了目前的含有燧石的白云岩。本文提出了白云岩及其燧石成因的解释机理。     

柴油机供油系统中的油—汽两相流及对不规则喷射产生的影响

本文阐明了柴油机供油系统中油—汽两相流与不规则喷射的内在联系．分析了不规则喷射产生的机理，并指出在高速小负荷工况下，供油系统中的汽泡是产生不规则喷射的主要原因．     

平面连杆机构中公共约束数与静不定次数的研究

本文就平面机构中从动杆组的分组方法以及公共约束数与其静不定次数的关系进行了研究，得出了平面机构中公共约束数与其静不定次数相等的重要结论；当多环平面机构的某独立环含有公共约束时，其机构的从动杆组仍然具有运动的确定性，只是其从动杆组需要进行再分组。     

掺杂聚乙炔导电机理研究

本文以多烯(17个碳原子)模拟反式聚乙炔链,位于两个多烯链平面之间的钠原子为掺杂剂,用 CNDO/2方法讨论了掺杂聚乙炔的微观导电机理,尝试并分析了用轨道理论的离域方法处理定域问题的具体方法.在我们的计算方法及计算范围内、负电孤子借助于钠原子在两链间跃迂。在低量掺杂情况下,参考链上孤子的存在对这种跃迂起辅助作用;电荷密度、原子轨道布居、能量分割及沿分子轨道形状等的结果同样支持了这一结论.     

三十烷醇乳剂配制技术及其机理的研究

三十烷醇是一种新型的植物生长调节剂,本文研究了三十烷醇乳剂的最佳配制条件,采用二次热水配制法,二次水温均为84℃—86℃,近千次实验表明,使用效果很好,本法制备快速,简易,适用于农村大面积大量配制,且乳剂质量稳定,能长期保存,适用于提前配制。     

烧结型多孔表面管强化沸腾传热的研究

在前人研究的基础上,本文根据沸腾换热、多孔物质内传热传质及毛细管中两相流的理论及实验,提出了烧型多孔表面沸腾换热的改进模型,再据此而得到新的烧结型多孔表面泡态沸腾换热关联式,与实验结果比较,偏差在士30%以内。关联式适用于F-11,F-12,F-22,F-113,F-114。