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叶子飘 《重庆大学学报(英文版)》2005,4(3):183-184
1 Introduction a In this paper, we calculated the capture rates of pep solar neutrino in the chlorine and gallium solar neutrino experiments according to the standard solar model (SSM)[1-3] in which there are five separate neutrino sources within proton-proton chain involving the following nuclear reactions. 2 p + e ?+ p → H + νe (1) 2 p + p → H + e ++ νe (2) 2 Approximation calculation The rate of the pep reaction, p + e ?+ p → 2 H + νe, can be expressed in terms of the rate of reacti… 相似文献
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中学化学的铜、锌原电池实验中,由于实验用的锌电极不纯而出现与铜电极用导线相联后插入稀H_2SO_4溶液中时,锌电极上仍有大量气泡产生,影响了教学效果。本文介绍二个制取该实验用的锌电极的方法,用于该实验,效果较好。 相似文献
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电解质溶液导电的机理是依赖溶液内的正、负离子在外加电场的作用下,分别向两个电极作定向移动,并且在电极发生电极反应,以完成在两个电极之间的电荷传输。现以电解NaCl溶液为例来看两个电极的电极反应:(图一) 在阴极上:H~ e→1/2H_2; 在阳极上:Cl~-→1/2Cl_2 e。对两个电极来说,在阴极每失去一个电子,阳极就能得到一个电子。而阳极得到的这个电子在外电路由于电源电动势的作用又跑回到阴极。正是大量电子的这种循环运动才形成了整个电路的电流,所以,通过溶液的电流强度应该等于导线中的电流强度。同时,通过以上分析可知:无论在溶液内或者在外电路都不可能有电 相似文献
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高中化学课本上,在介绍电解食盐水以制取烧碱和氯气时,电极反应式是这样表述的:阴极、2H~++2e=2H 2H=H_2 阳极:2Cl~--2e=2Cl 2Cl=Cl_2 我认为上述阴极的电极反应式未能将阴极反应的实质表现出来。因为在阴极放电的 H~+是由水电离产生的,而水是弱电解质,写离子方程式时仍应保持分子形式。因此,电解食盐水时,正确的阴极的电极反应表达式应该是:(阳极电极反应式同上。) 相似文献
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1 实验原理 氧化还原反应: Cr2O72-+14H++3Fe=2Cr3++2Cr2++7H2O 电池符号:(-)Fe|Fe2+||Cr2O72-,Cr3+,H+|碳棒(+) 电极反应: 正极 Cr2O72-+14H++6e=2Cr3++7H2O 负极 3Fe-6e=3Fe2+ 相似文献
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孟一梅 《湖州师范学院学报》2011,33(2):17-20
H(B)是单位球B上的全纯函数的全体,对g∈H(B),讨论了Bloch空间上的广义Cesàro算子Tg的本性模估计.利用上极限,给出了‖Tg‖e,B→B的表示.此处‖Tg‖e,B→B表示Bloch空间上的广义Cesàro算子的本性模. 相似文献
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文章利用电聚合法制备出银/乙二胺修饰电极,并研究H2O2在该修饰电极上的电化学行为,并考察实验条件的影响.实验结果表明:在pH6.7的磷酸盐缓冲溶液中,银/乙二胺修饰电极对H2O2具有良好催化还原作用,H2O2在修饰电极上产生一对较好的氧化还原峰,峰电位分别为Epa=0.344 V,Epc=-0.215 v.线性范围为... 相似文献
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含有铁等杂质的金属锌比纯锌与稀盐酸反应生成氢气的速率快。其热力学本质是:纯锌与稀盐酸反应时,氢气在锌上析出,而锌含杂质铁时,氢气在铁上析出,氢气在铁上比在锌上的析出过电势小,使锌与稀盐酸的反应趋势增大;其动力学本质是:纯锌与稀盐酸反应时,H+离子从溶液本体向锌扩散,而锌含杂质铁时,H+向铁扩散,H+的迁移方向改变,二重电极锌实现了空间分离,减弱了Zn2+与H+之间的静电斥力,使H+迁移速率加快,产氢速率提高。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献