求和或积分号内求导方法在物理学中的应用

总结归纳了在物理学中求和或积分号内的求导方法,并给出了主要应用实例.     

ETHNICITY, GENERATION, AND SCHOOL ATTAINMENT OF ASIANS, HISPANICS, AND NON-HISPANIC WHITES

Research on immigration and attainment in U.S. schools typically does not separate out generation of U.S. residence, a critical factor in attainment. This article explores immigrant generation effects (native, child of immigrant, immigrant) on schooling attained for Asians, Hispanics, and non-Hispanic whites, using Current Population Survey data. Previously unpublished cross-sectional data are presented. Regressions predicting school years completed show variable generation-by-ethnicity effects. Asian attainment increases sharply between immigrant and child-of-immigrant generations, leveling off thereafter. Hispanic attainment improves with successive generations of U.S. residence. Non-Hispanic white attainment peaks in the child-of-immigrant generation and declines for later generations.     

论太平天国时期的周庄枪匪集团

:以费秀元、费金绶父子为首的周庄枪匪集团 ,是清末太湖地区众多枪匪中势力较大的一支。费氏通过捐输取得官衔、功名 ,约束土匪劣性 ,获地主士绅和清政府的支持。太平军攻占苏州后 ,该集团负隅顽抗 ,继而被迫假意受抚 ,最终公开投降清军。在李鸿章率淮军攻占太平天国苏福省的战斗中 ,周庄枪匪绘呈地图、担任向导、随军作战 ,出力颇巨 ,后为李鸿章收编。     

IP Filter包过滤防火墙在校园网上的实现

介绍了利用IP Filter包过滤功能在网络出口组成防火墙实现网络安全,并通过一个校园网作为实例,说明包过滤规则的制定和在IP Filter上的配置。     

重视社区体育提高生活质量--无锡市社区体育现状的调查及研究

通过广泛的社会调查,笔者对无锡市社区体育现状进行了分析研究,证实了社区体育在提高现代生活质量中所起的重要作用以及在发展过程中所存在的问题,并提出了建议对策。     

基于长江经济带的金融资源与农业资本化耦合实证研究

农业资本化的本质是农业资本投入的不断增加,金融资源是实现农业资本化的根本保障,只有顺应农业资本化方向的金融资源才可减少无效或低效供给,增加有效或高效供给。本文首先从理论出发论述了金融资源与农业资本化存在相互作用的耦合机制。金融资源通过资本形成机制、技术进步机制和要素替代机制促进农业资本化发展,农业资本化的发展能带来农业生产效率和数量的提高,促进农业经营性收益增加,从而刺激农村地区金融服务产品的需求和供给得到提升,为金融资源总量增加提供累积空间。再基于长江经济带10省市2008—2019年样本数据,通过构建金融资源与农业资本化两大指标体系,运用熵值法和耦合协调度模型对金融资源与农业资本化的耦合协调程度进行实证检验。结果表明,金融资源与农业资本化的发展整体呈上升趋势,但二者存在背离的现象,农村金融资源不足或错配阻碍着金融资源与农业资本化相互促进的良性循环。     

读者接受视角下《庄子》英译本海外传播策略研究

《庄子》是我国重要的文化典籍,其海外传播现状对我国文化典籍的对外推广具有重要参考意义。通过译入语受众线上问卷调查发掘《庄子》英译本海外传播现状。结果显示,《庄子》英译本对外传播存在主体职责不清、传播内容缺乏本土适应性、传播渠道相对较少和传播定位不够精准等问题。鉴于此传播现状,可以通过明确传播主体职责、优化传播主体格局 ,优化传播内容、提升本土适应性,运用现代化媒介、拓宽传播渠道,采取针对性策略、顺应读者心理等传播策略提升我国文化典籍对外传播效果。     

企业知识管理的综合评价指标体系及评价实例

文章针对企业知识管理状况的综合评价问题,根据当前知识管理研究的焦点对反映企业知识管理状况的指标进行了分类,形成了一个系统化的知识管理综合评价指标体系,在此基础上建立了企业知识管理的模糊综合评价模型,并利用模型对中国石油集团某测井公司的知识管理进行了定量分析与综合评价.     

基于网络流的航空公司飞行员人力资源规划模型

飞行员在各机型、各岗位的流动安排是航空公司人力资源规划的重要内容,是满足航空公司生产需求的主要措施之一.本文根据航空公司实际工作中飞行员流动安排的各种方案与规定利用网络图进行描述并以此建立数学规划模型,最后采用网络流理论给出模型算法.     

Compliance Versus Risk in Assessing Occupational Exposures

Assessments of occupational exposures to chemicals are generally based upon the practice of compliance testing in which the probability of compliance is related to the exceedance [γ, the likelihood that any measurement would exceed an occupational exposure limit (OEL)] and the number of measurements obtained. On the other hand, workers’ chronic health risks generally depend upon cumulative lifetime exposures which are not directly related to the probability of compliance. In this paper we define the probability of “overexposure” (θ) as the likelihood that individual risk (a function of cumulative exposure) exceeds the risk inherent in the OEL (a function of the OEL and duration of exposure). We regard θ as a relevant measure of individual risk for chemicals, such as carcinogens, which produce chronic effects after long-term exposures but not necessarily for acutely-toxic substances which can produce effects relatively quickly. We apply a random-effects model to data from 179 groups of workers, exposed to a variety of chemical agents, and obtain parameter estimates for the group mean exposure and the within- and between-worker components of variance. These estimates are then combined with OELs to generate estimates of γ and θ. We show that compliance testing can significantly underestimate the health risk when sample sizes are small. That is, there can be large probabilities of compliance with typical sample sizes, despite the fact that large proportions of the working population have individual risks greater than the risk inherent in the OEL. We demonstrate further that, because the relationship between θ and γ depends upon the within- and between-worker components of variance, it cannot be assumed a priori that exceedance is a conservative surrogate for overexposure. Thus, we conclude that assessment practices which focus upon either compliance or exceedance are problematic and recommend that employers evaluate exposures relative to the probabilities of overexposure.