三相异步电动机断相保护器

详述了断相保护器的电路结构与工作原理。当电容C2上的电压上升到BT33C的峰点电压时,小灵敏继电器KA通电,切断电动机的电源,从而避免了三相异步电动机单相运行致使电流过大而被烧毁。为了使小灵敏继电器KA通电充分,能确保其常闭触点断开,及时切断电动机的电源,应使BT33C的电流不会很快降到谷点电流以下,电容C2上的电压能较长时间的大于BT33C的谷点电压。由于电容C2上的电压不能跃变,这样可避免电网三相电压瞬间不平衡造成断相器误动作。     

压控晶体振荡器的设计

本文提出了晶体和频率控制元件的模型,介绍了基本电路的设计,并详细讨论了压控晶体振荡器调制器产生最小音频失真的必要条件。     

上海股市五年综观

上海股市五年综观□张国枢，张开宇上海股市自１９９０年１２用１９日发布实施上证指数以来，至１９９５年１１月１７日，已运行了５后，作为我国的一个新兴资产市场，表现出极大的生命力租发展前景。其间，风风雨雨，涨涨跌跌，吸引了千万人的积极参与，为国内外各界人士...     

关系和谐≠人 自然 人

人是不能离开关系而存活的,从哲学的维度来看,关系就是人的一种生存状态,为人的生存和发展提供了空间和可能。某种程度上说,关系也就是人类社会的代名词,它内涵有社会属性。当然这些关系是在实践中生成的,并且是和实践同构的关系。关系的本质就是一种动态的和谐,而不是一加一的累积。我们可以从社会化的关系、社会关系以及社会内的关系等角度来认识关系。鉴于现在人类面临着越来越多的严峻挑战,旧有的生存关系的“和谐”状态遭到破坏,全面的属人关系产生了一种失衡和异化。在这新的生存环境之中,怎样去建立一种真正的和谐关系,来体察人在现实生活空间中生存和发展的可能性,是值得我们深思的问题。     

Key Determinants of the Stage of Internationalisation of Australian Wineries

A four stage measure capturing, awareness, interest, trial and adoption is employed to identify the key determinants of the stage of internationalisation of Australian wineries. Drawing from data from 292 wineries and using structural equation modelling techniques, this paper analyses the effects of a multitude of factors previously hypothesised to influence the stage of internationalisation. The results indicate that while these wineries exhibit characteristics described in the extant literature, significant differences remain. The paper concludes by discussing the limitations and areas for further research.     

Expected exponential utility maximization of insurers with a Linear Gaussian stochastic factor model

In this paper, we consider the problem of optimal investment by an insurer. The wealth of the insurer is described by a Cramér–Lundberg process. The insurer invests in a market consisting of a bank account and m risky assets. The mean returns and volatilities of the risky assets depend linearly on economic factors that are formulated as the solutions of linear stochastic differential equations. Moreover, the insurer preferences are exponential. With this setting, a Hamilton–Jacobi–Bellman equation that is derived via a dynamic programming approach has an explicit solution found by solving the matrix Riccati equation. Hence, the optimal strategy can be constructed explicitly. Finally, we present some numerical results related to the value function and the ruin probability using the optimal strategy.     

Ownership concentration and bank risk: international study on acquisitions

This paper explores the effects of different types of bank ownership concentration on changes in bank risk during acquisition years. Using multi-country data from 2000 to 2006, during which market failures caused by various crises and government interventions are less influential to acquisition decisions, we collect 505 banking acquisition deals from 23 countries to examine which type of ownership concentration (such as financial intermediary, capital investor, non-financial, and state ownership) brings larger changes to an acquirer’s risk from pre-acquisition year to post-acquisition year (including non-performing loans, capital adequacy ratio, loan loss reserve, and credit rating). The empirical analyses show that acquirer banks with a concentration of shares owned by financial intermediaries and non-financial firms experience larger risk changes during acquisition years. In contrast, the risk changes of acquirer banks with a concentration of capital investors and state ownership are lower. Robustness checks from the random effect estimation, instrumental variables model, reverse causality, and different subsamples of (non-)U.S. or different levels of regulation enforcement confirm these results.     

How supply chain architecture and product architecture impact firm performance: An empirical examination

In order to enhance performance, manufacturing firms are building various capabilities and utilizing supply chain networks that are geographically dispersed around the globe. This study examines how decisions related to supply chain architecture and product architecture influence organizational competitiveness. Building on the co-specialization perspective, we evaluate the performance implications of product modularity and supply chain agility. While, product modularity constitutes a product configuration related to sourcing and assembling of products, supply chain agility is a supply chain configuration related to velocity (sensing, comprehending, and responding) and visibility (supplier network, internal operations, and external environment). Both the product and supply chain architectural decisions can impact performance, individually and in conjunction with each other. We empirically test the hypothesized relationships using data collected from 103 manufacturing firms. Results show that supply chain agility and product modularity directly enhance responsiveness and enable organizations to reduce cost. Furthermore, supply chain agility partially mediates the relationship between product modularity and both responsiveness and cost reduction. We elaborate on the key contributions of this study for both research and practice, discuss limitations, and also offer various avenues for further research.     

Information congruity in scarcity appeal: A structural equation modeling study of time-limited promotions

Although market scarcity such as time restriction is widely used in retail advertisements, its impact on product message processing and product evaluation is still subject to controversy. In this study, analyses through structural equation modeling indicated that (i) scarcity had no impact on product message processing, (ii) scarcity had a direct impact on product evaluation as a heuristic cue when the value inferred from scarcity was congruous with the worth derived from product message, and (iii) scarcity lost its impact on product evaluation when the value inferred from scarcity was incongruous with the worth derived from product message, and the incongruity prompted scrutiny of product message, resulting in a mediated impact of product message on product evaluation through product message processing. In conclusion, the results supported an information congruity theory of market scarcity.     

将数学建模引入高等数学教学中的典型案例

首先阐述了将数学建模思想融入高等数学教学内容中的意义,接着从高等数学中的基本概念和基本定理出发,通过具体案例说明如何将数学建模案例融入在高等数学教学中。最后给出了根据高等数学内容选编的典型建模案例。