多智能体组织中个体行为的影响因素研究--分配政策、协同作用的影响分析

分析了在不同的产出分配政策、组织协同作用水平和个体智能体偏好情况下,组织整体行为与其成员智能体行为之间的关系.通过对多智能体组织模型的构建,借助数学分析和计算机模拟,得到了关于多智能体组织规模、生产函数和自组织工作等不同假设情况下的组织行为特点和个体最优行为策略.研究结论为认识多智能体组织的行为规律及其管理制度设计提供理论基础.     

机械激活和固相反应合成Mg2Ni合金

通过机械合金化机械激活和固相反应制备了Mg2Ni合金,用XRD和EDS对合金进行了分析.实验研究表明混合粉经机械研磨激活和适当增加固相烧结反应的温度,这样可有效增加固态扩散反应能力,有利于固相反应进行,使形成Mg2Ni的量明显提高.实验结果发现,成分配比、烧结反应温度及时间均影响最终Mg2Ni的纯度,其中反应温度是影响固相反应Mg2Ni形成的重要因素,当Mg增量取0.5%,烧结温度为700 ℃,保温时间6 h时可得到组织单一和纯度较高的Mg2Ni合金相.     

On thein vitro bioassay for measuring melanophoretic activity

Résumé Les auteurs décrivent diverses modifications au test original deShizume et al. pour mesurer l'activité mélanophorétiquein vitro. Une analyse mathématique des résultats obtenus avec cet étalonnage en montre les caractéristiques satisfaisantes.

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Acknowledgments. This work was supported by research grants (No. A-2543, C₁, C₂) from the National Institute of Health (NIH) of the U.S. Public Health Service and Contract No. AF 419657)-224 with the School of Aviation Medicine, U.S. Air Force, Wright Air Development Division, Lackland Air Force Base, Texas.     

Reaction path of protein farnesyltransferase at atomic resolution

Protein farnesyltransferase (FTase) catalyses the attachment of a farnesyl lipid group to numerous essential signal transduction proteins, including members of the Ras superfamily. The farnesylation of Ras oncoproteins, which are associated with 30% of human cancers, is essential for their transforming activity. FTase inhibitors are currently in clinical trials for the treatment of cancer. Here we present a complete series of structures representing the major steps along the reaction coordinate of this enzyme. From these observations can be deduced the determinants of substrate specificity and an unusual mechanism in which product release requires binding of substrate, analogous to classically processive enzymes. A structural model for the transition state consistent with previous mechanistic studies was also constructed. The processive nature of the reaction suggests the structural basis for the successive addition of two prenyl groups to Rab proteins by the homologous enzyme geranylgeranyltransferase type-II. Finally, known FTase inhibitors seem to differ in their mechanism of inhibiting the enzyme.     

CREB regulates hepatic gluconeogenesis through the coactivator PGC-1

When mammals fast, glucose homeostasis is achieved by triggering expression of gluconeogenic genes in response to glucagon and glucocorticoids. The pathways act synergistically to induce gluconeogenesis (glucose synthesis), although the underlying mechanism has not been determined. Here we show that mice carrying a targeted disruption of the cyclic AMP (cAMP) response element binding (CREB) protein gene, or overexpressing a dominant-negative CREB inhibitor, exhibit fasting hypoglycaemia [corrected] and reduced expression of gluconeogenic enzymes. CREB was found to induce expression of the gluconeogenic programme through the nuclear receptor coactivator PGC-1, which is shown here to be a direct target for CREB regulation in vivo. Overexpression of PGC-1 in CREB-deficient mice restored glucose homeostasis and rescued expression of gluconeogenic genes. In transient assays, PGC-1 potentiated glucocorticoid induction of the gene for phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme in gluconeogenesis. PGC-1 promotes cooperativity between cyclic AMP and glucocorticoid signalling pathways during hepatic gluconeogenesis. Fasting hyperglycaemia is strongly correlated with type II diabetes, so our results suggest that the activation of PGC-1 by CREB in liver contributes importantly to the pathogenesis of this disease.     

经济的耐腐蚀泵的综合设计

本文探讨了水泵的腐蚀机理,在分析调研、试验的基础上,对经济的耐腐蚀泵的可靠性进行了深入的研究,提出了经济的耐腐蚀泵的综合设计。     

基于随机化算法的鲁棒控制器设计

将学习理论与鲁棒控制相结合,采用随机化算法针对实参数不确定系统讨论了鲁棒控制器的设计问题,研究表明,在不考虑最坏情况的意义下,随机化算法可以显著降低计算复杂性,另外,当不确定区间参数以多线性非线性的方式出现在特多项式系数中时,采用随机算法具有明显的优点并且是非常有效的。文中给出了计算实例。     

概率方法在鲁棒控制器综合中的应用

针对具有实参数不确定性的一类线性和多线性区间控制系统,在现有的鲁棒稳定性分析和设计的工具基础上,结合概率方法提出了一种鲁棒控制器的设计方法和步骤,文中的计算实例表明了这种方法的可行性和有效性。     

昭通铅锌矿床闪锌矿微量元素地球化学特征

昭通铅锌矿床是滇东北富锗铅锌矿集区的一个大型矿床。前人对该矿床的研究集中于成矿构造背景、成矿物质和成矿流体特征、构造控矿特征、矿床成因以及成矿预测等方面,并取得了显著的研究成果。然而,在矿床成因方面仍存在较大争议。闪锌矿是铅锌矿床的主要矿石矿物之一,运用闪锌矿微量元素地球化学特征研究,可以作为判别矿床成因的一种标志。在总结矿床地质特征的基础上,开展闪锌矿矿相学及微量元素地球化学的研究。