Courtship behavior in Rhinoclemmys areolata from western Tabasco, Mexico (Testudines: Emydidae)

Observations in nature and captivity reveal that members of the population of Rhinoclemmys areolata of western Tabasco, Mexico, exhibit underwater courtship and mating and appear to lay one egg per nest.     

低铬奥氏体焊接新材料产生

由我校材料系王来教授负责主持的国家“九五”重点科技攻关项目“低铬奥氏体焊接材料的开发与应用”通过教育部专家组的鉴定 .他们历经三载多的艰苦钻研和上千次的反复试验才研制成功的低铬奥氏体焊接材料基本解决了 2 0世纪六七十年代以来国内外关于异质接头在高温服役过程中提前失效这一难题 ,填补了该领域的国内外空白 ,并达到了国际领先水平 ;其开发与应用的经济效益和社会效益及国内外市场的前景广阔 .新开发的低铬奥氏体焊接材料已进行了中试生产和现场应用考核等过程 ,其产品可替代目前国内外大量使用的Ａ30 2及Ａ30 7奥氏体不锈钢焊…     

世界最强木桥-挪威雷纳河军用桥介绍

由于木结构所具有的许多优点,在工程中的应用越来越受重视。挪威雷纳河军用桥设计荷载远超普通公路桥梁,被认为是世界最强木桥。本文对该桥的设计与建造进行介绍,希望能为我国木结构桥梁的应用提供借鉴。     

交错群A_p的数量刻画(英文)

证明了若p≥ 5且p与p - 2 均为素数 ,则交错群Ap 可用元的阶刻画     

Analysis of the Ecological and Toxicological Properties of Dyes with Reference to Safety Data Sheet

In recent years,the public awareness and concern forthe environment has increased significantly.This has re-sulted in tougher legislation and more stringent standardsfor the industry to comply.In the past,the cost,fast-ness properties and colour yield were the prime consider-ations when dyeing systems were to be selected.Today,special emphasis is also laid on the environmental prop-erties of the dyes.In this paper,the various ecologicaland toxicological properties from safety data sheet of dif-ferent dye classes were studied so as to assess the impactof the textile dyeing effluent on the environment qualita-tively and quantitatively.The results showed that eachdye class produces waste of vastly differing quantities and characteristics.Moreover,the variability of the pollu-tion parameters within each dye class was found to be very large,thus it was believed that substituting dyes of lower degree of pollution to the environment can be aneffective means to reduce the degree of pollution of the dyeing efflue     

Research on Insurance Pricing

1.INTRODUCTIONInsurancepricingisaneternalthemeinthestudyofinsurance.Whenwedesignainsuranceproduct,wemusttogiveapricefortheproductinordertoselltheproductininsurancemarkets.Whatiscalledinsurancepricingisactuallytomakeinsurancepremiumofinsuranceproduct.Reasonablepricingofinsuranceproductisofutmostimportancefortheexistenceanddevelopmentofinsurancecompany.Ifpremiumismadetoohigh-priced,althoughinsurancecompanycanobtainhighprofitofunderweightingadcanheightencapacityofinsurancecompanyinpaymentofd…     

论怎样做一个科学家

我们如何才能更加发扬光大科学拓展文明的作用 ?首先 ,我们必须懂得科学     

温度和应变率对拉伸载荷下记忆合金本构关系的影响

用于高温Split Hopkinson Bar(SHB)试验的新型快速加热电炉，可在1min左右将试件加热至500度，最高可加热至1000度，且金属材料和非金属材料均可加热，在20－800度和0．00208－350s^-1范围内研究了温度和变率对拉伸载荷下铁基形状记忆合金本构关系的影响，结果表明，随着应变率提高，材料强度提高，延伸率降低，材料强度，延伸率及应变率敏感性随温度升高而降低。     

来自太空的生命原料

多少世纪以来，彗星铭刻有人类记忆中的是灾难，到公元前400年时，中国的天文学家已记述了29种彗星，许多是灾害的预兆。亚里士多德关于彗星是来自神的预告的假设支配了古希腊全盛时期之后两千年的西方文明。即使是20世纪的末尾，慧星与流星都在死亡与毁灭的电影故事中起重要的作用。彗星的威胁原来不是完全凭空想象的。现代科学业已揭示，一次巨大的碰撞可能导致了恐龙灭绝，