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81.
对Ge-As-Se玻璃系统,进行了高能γ射线辐照试验。结果表明:辐照使样品的密度(ρ),热膨胀系数(α)和光学带隙(Eopt)等参数产生了变化,并与组成有关。样品的组成为化学计量比时,其辐照灵敏度与As2Se3含量具有线性规律,而非化学计量比组成的样品无明显规律性关系。这是γ射线引起玻璃化学键和结构变化而产生的效应。硒化物硫系玻璃在作为剂量计材料应用方面具有良好的前景。  相似文献   
82.
智能控制电采暖系统的应用   总被引:1,自引:0,他引:1  
对当前常用的几种采暖方式进行了分析比较,重点对节能智能控制电采暖系统的工作原理、技术特点、应用前景予以阐述.  相似文献   
83.
Micro panels characterized by large numbers of individuals observed over a short time period provide a rich source of information, but as yet there is only limited experience in using such data for forecasting. Existing simulation evidence supports the use of a fixed‐effects approach when forecasting but it is not based on a truly micro panel set‐up. In this study, we exploit the linkage of a representative survey of more than 250,000 Australians aged 45 and over to 4 years of hospital, medical and pharmaceutical records. The availability of panel health cost data allows the use of predictors based on fixed‐effects estimates designed to guard against possible omitted variable biases associated with unobservable individual specific effects. We demonstrate the preference towards fixed‐effects‐based predictors is unlikely to hold in many practical situations, including our models of health care costs. Simulation evidence with a micro panel set‐up adds support and additional insights to the results obtained in the application. These results are supportive of the use of the ordinary least squares predictor in a wide range of circumstances. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
84.
本文基于逃离"北上广深"背景,研究了一线城市对二三线城市的房价涟漪效应,并从城市规模大小、距一线城市远近和涟漪效应高低三个方面,对比分析各因素对涟漪效应的影响.研究发现:1)逃离"北上广深"背景下,产业相似度、生活舒适性差距、交通便捷性、住房市场信息距离、社会文化距离、就业增长率、开放度和总储蓄均对涟漪效应表现出显著促进作用;2)二线城市各因素的影响程度均大于三线城市;3)随着与一线城市距离的增加,产业相似度、交通便捷性、就业增长率和开放度的影响呈递减趋势,生活舒适性差距呈递增趋势,住房市场信息距离和总储蓄基本与距离无关;4)随分位数提高,多数变量的影响程度增强,表现出"加速效应".  相似文献   
85.
The increasing amount of attention paid to longevity risk and funding for old age has created the need for precise mortality models and accurate future mortality forecasts. Orthogonal polynomials have been widely used in technical fields and there have also been applications in mortality modeling. In this paper we adopt a flexible functional form approach using two‐dimensional Legendre orthogonal polynomials to fit and forecast mortality rates. Unlike some of the existing mortality models in the literature, the model we propose does not impose any restrictions on the age, time or cohort structure of the data and thus allows for different model designs for different countries' mortality experience. We conduct an empirical study using male mortality data from a range of developed countries and explore the possibility of using age–time effects to capture cohort effects in the underlying mortality data. It is found that, for some countries, cohort dummies still need to be incorporated into the model. Moreover, when comparing the proposed model with well‐known mortality models in the literature, we find that our model provides comparable fitting but with a much smaller number of parameters. Based on 5‐year‐ahead mortality forecasts, it can be concluded that the proposed model improves the overall accuracy of the future mortality projection. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
86.
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).  相似文献   
87.
网络科学的理论模型探索及其进展   总被引:13,自引:1,他引:12  
简要评述了复杂网络分类和研究概况,着重概述了近年来本研究项目在网络科学的理论模型方面的探索及其进展。提出和探索了若干模型:和谐统一的混合择优模型,大统一混合网络模型,量子信息网络模型,纳米相干网络模型,局域世界演化模型,非局域连接模型,社区网络模型,属性连接网络模型,含权科学家合作模型,同步最优网络模型,以及广义同步和集团同步等问题。  相似文献   
88.
《Journal of Natural History》2012,46(10):1447-1483
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.  相似文献   
89.
老舍短篇小说《柳家大院》讲述了北平一个“狗窝”般的大杂院中,公公和小姑子虐待小媳妇至死的故事,其以独特的叙事视角建构了叙述者与隐含作者的距离与冲突,营造了“看与被看”的多重审视模式.《柳家大院》因此激发着读者的同情、悲愤、无奈与哀叹的道德反应,呈现了老舍小说叙事的民间伦理.  相似文献   
90.
江丽丽 《科技信息》2009,(33):96-96
抠像大多运用于电影和电视的特效制作上,因此,掌握好这项技术是一个高端的影视制作人的必备条件之一。本文主要叙述了AfterEffects中抠像的一般流程.并且介绍了常用的几种抠像方法以及每种方法适用的环境。  相似文献   
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