共查询到20条相似文献，搜索用时 171 毫秒
1.
The density and the refractive index for various compositions of heavy metal fluoride(HMF) glasses,used to make low-loss optical wave-guides,have been measured by standard archimedes method and by using as Pulfrich refrctometer respectively.The density as a function of composition is calculated considering the effective volume of the ions contained in the glass to be invariant.The refractive index as a function of composition is also calcuated.based on the Lorenz-Lorentz equation,by computing the electronic polarizability of HMF glasses.All calculated results are in good agreement with the observed data. 相似文献
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Wang Junsheng 《东南大学学报》1996,(1)
ＶａｒｉｏｕｓＧｒｏｗｔｈＰａｔｅｒｎｓａｎｄＭｏｒｐｈｏｌｏｇｙＴｒａｎｓｉｔｉｏｎｓｏｆＭｅｔａｌｌｅａｖｅｓＷａｎｇＪｕｎｓｈｅｎｇ（王俊生）（１．ＮａｔｉｏｎａｌＬａｂｏｆＭｏｌｅｃｕｌａｒａｎｄＢｉｏｍｏｌｅｃｕｌａｒＥｌｅｃｔｒｏｎｉｃ... 相似文献
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Xizu Wang Durga Venkata Maheswar Repaka Ady Suwardi Qiang Zhu Jing Wu Jianwei Xu 《天津大学学报(英文版)》2023,(3):209-215
Liquid metal gallium has been widely used in numerous fields, from nuclear engineering, catalysts, and energy storage to electronics owing to its remarkable thermal and electrical properties along with low viscosity and nontoxicity. Compared with high-temperature liquid metals, room-temperature liquid metals, such as gallium(Ga), are emerging as promising alternatives for fabricating advanced energy storage devices, such as phase change materials, by harvesting the advantageous properties of the... 相似文献
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QIN Feng CHEN Jiang-ping ZHANG Wen-feng CHEN Zhi-jiu 《浙江大学学报(A卷英文版)》2007,8(2):197-204
INTRODUCTION Metal hydrides are special alloys which absorb and desorb hydrogen reversibly. At room temperature, metal hydrides could absorb as much hydrogen as liquid hydrogen of the same volume under much lower pressure and much higher temperature (Güther and Otto, 1999). Massive reaction heat is generated accompanying this reaction, which could be used for waste heat recovery, solar energy utilization and re-frigeration with no side effect to environment (Izhvanov et al., 1996). Con… 相似文献
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《数理天地(初中版)》2004,(5)
Worms don't usually get much respect. To most people.they are slimy,dirty,and gross.But there is plenty in the humble worm to admire and inspire,say scientists in California. The jaws of marine worms, in particular, are incredibly strong. And new research is bringing researchers closer to developing hard materials that imitate nature. 相似文献
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fixation rate and color fastness,but the Lanasol type of wool fiber used reactive dye is not so applicable to dye the soybean protein fiber.0针织工业Knittin 相似文献
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Andrew T. Knudsen 《Paedagogica Historica: International Journal of the History of Education》2016,52(5):507-524
AbstractWhen historians discuss the impact of examinations on elementary education in mid-Victorian England and Wales they typically focus on the Revised Code of 1862. The Revised Code is famous for instituting a policy of “payment-by-results” for teachers in state-supported voluntary schools. “Payment-by-results” made government grants to schools – and, by extension, for teachers’ salaries – contingent upon student attendance and pass rates in reading, writing and arithmetic. As this article emphasises, however, “payment-by-results” was not the first, or even the most significant, instance in which competitive examination was used by the state as an instrument for establishing the pedagogical fitness and salaries of teachers. Less often explored by historians is the formative role that state-mandated competitive examinations for teachers played in developing a professionally aspirant body of schoolteachers and, consequently, the schoolteachers’ later role in developing competitive examination as a broad-scale national accreditation apparatus. But while the use of competitive examinations came to shape modern British academic and professional life in fundamental ways, the strengthening effects that they had for certain occupations and institutions, such as physicians, civil servants and middle-class secondary schools, were in fact ultimately denied to state teachers and the elementary education sector generally. With the introduction of “payment-by-results” in 1862, competitive examinations were converted into an instrument that weakened rather than strengthened teachers’ professional identity and policy influence. This article explains how the nineteenth-century English state structured examinations and examination results to manipulate the professional status of teachers in order to suit state priorities during different stages of national development. This historical narrative is framed in reference to present-day examination-based reforms of teacher compensation systems such as performance-related-pay and value-added modelling. 相似文献
8.
ThisstoryisaboutfourFloridafirefightersnamedEverybody，Somebody，Any－bodyandNobody．Therewasanimportantjobtobedone．Everybodywasaskedtodoit．EverybodywassurethatSome－bodywoulddoit．Anybodycouldhavedoneit．ButNobodydidit．SomebodygotangrybecauseitwasEverybody＇sjob．Ev－erybodythoughtAnybodycoulddoit．NobodyrealizedthatEv－erybodywouldn＇tdoit．Itend－edupthatEverybodyblamedSomebody，whenactuallyNo－bodyblamedAnybody．参考译文：这个故事讲的是佛罗里达州的四名消防队员，他们的名字分别是… 相似文献
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This story is about four Florida fire fighters named Everybody, Somebody, Anybody and Nobody. There was an important job to be done. Everybody was asked to do it. Everybody was sure that Somebody would do 相似文献
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英语中的连词是一种虚词,在句子中不单独用作句子成分。连词按其性质可分为并列连词和从属连词。and,but,so,or就是大家所熟知的并列连词,在小学课文中接触过,也学习过。今天在这里简单地归纳总结。下面请四位连词先生作个自我介绍吧。 相似文献
11.
Phillip D. Tomporowski Catherine L. Davis Patricia H. Miller Jack A. Naglieri 《Educational Psychology Review》2008,20(2):111-131
Studies that examine the effects of exercise on children’s intelligence, cognition, or academic achievement were reviewed
and results were discussed in light of (a) contemporary cognitive theory development directed toward exercise, (b) recent
research demonstrating the salutary effects of exercise on adults’ cognitive functioning, and (c) studies conducted with animals
that have linked physical activity to changes in neurological development and behavior. Similar to adults, exercise facilitates
children’s executive function (i.e., processes required to select, organize, and properly initiate goal-directed actions).
Exercise may prove to be a simple, yet important, method of enhancing those aspects of children’s mental functioning central
to cognitive development.
相似文献
| Phillip D. TomporowskiEmail: |
12.
1.Mr Yang is rich______he is not happy.2.It's cold,_____Miss Li will close the window.3.It is usually warm_____wet in spring. 相似文献
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Sumit Bhaduri 《Journal of Science Education and Technology》2003,12(3):303-308
The article reviews the strikingly divergent viewpoints of intellectuals—scientists and non-scientists—about Science and Technology. It shows that while scientists implicitly accept the difference between Science and Technology, to non-scientists that difference is irrelevant. The most important differences between Science and Technology that lie in their relative scales, outputs and accuracy of predictions are highlighted. The complexity of and difficulty in trying to quantify the contribution of science and technology to economic growth are discussed. Views of science and technology that include their societal perceptions are recommended. 相似文献
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16.
王松海 《初中生世界(初三物理版)》2004,(10)
Tomisacleverboy.Onhisfirstdayinschool,helearnedthreewords:I,youandshe.Theteachertaughthimhowtomakesentenceswiththosewords.Theteachersaid,“I,Iamyourteacher.(Pointingtoagirl)She,sheisyourclassmate.You,youaremystudent.”Aftersupper,Tom’sfatheraskedhimwhathehadlearnedatschool.Tomsaidatonce,“I,Iamyourteacher.(Tohismother)She,sheisyourclassmate.You,youaremystudent.”Hisfathergotangryandsaid,“I,Iamyourfather.(Tohismother)She,sheisyourmother.You,youaremyson.”Thenextmorningatschooltheteach… 相似文献
17.
苏程 《英语大王(小学)》2003,(12)
I was born in a city by the sea.I like the sea. The sea is beautiful;fishes in the sea are beautiful, too.Fishes are free.They can swim everywhere in the sea.When winter comes,they change places. But Some fishes don't.Sometimes I want to be a 相似文献
18.
ProfessorBlackwasgoingtomeethisstudentsonthenextday,sohewroteontheblackboard:“ProfessorBlackwillmeettheclasstomor-row.”Astudent,seeinghischancetodisplayhissenseofhumorafterreadingthenotice,walkedupanderasedthe“c”intheword“class”.Theprofessornoticedthelaughter,wheeledaround,walkedback,lookedatthestudent,thenatthenoticewiththe“c”erased——calmlywalkedupanderasedthe“l”in“lass”,lookedattheflabbergastedstu-dentandproceededonhisway.Class,Lass and Ass@唐亚军$河北正定三中… 相似文献
19.
Henk van Oort 《英语辅导》2004,(5)
Air, water andAge 9-12Time 5 minutesFocus Animal vocabularyMaterials A small beanbag,rolled-up sock or similar object (not a ball, as this will tend to roll out of reach when dropped) 相似文献
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What's in the hat?What's in the hat?A mad cat?No.A fat bat?No.A bad rat?Yes ,you've got it!A bad rat is in the hat. 相似文献