共查询到20条相似文献，搜索用时 78 毫秒
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解法一（高考命题组给出的解法）：（１）１ｃｍ３ 晶体中阴、阳离子总数＝１ ００ｃｍａ×１０－８ｃｍ３,１ｃｍ３晶体中Ｎｉ２ + -Ｏ２ -离子对数＝１ ００ｃｍａ×１０－８ｃｍ３× １２,密度＝（ １ ００ｃｍａ×１０－８ｃｍ）３×７４ ７ｇ ｍｏｌ－１２×６ ０２×１０２３ｍｏｌ－１×１ ００ｃｍ３＝６２ ０ａ３ ｇ．ｃｍ-３。（２）设１ｍｏｌＮｉ０ ９７Ｏ中含Ｎｉ３ + ｘｍｏｌ,Ｎｉ２ +（０．９７-ｘ）ｍｏｌ。根据电中性：３ｘｍｏｌ +２（０．９７ -ｘ）ｍｏｌ＝２×１ｍｏｌ,ｘ＝０．０６。Ｎｉ２ + 为（０．９７-ｘ）… 相似文献
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［知识要点］ １．物质的量（ｎ） 物质的量是国际单位制中七个基本物理量之一，表示含有一定数目粒子的集体． 二．物质的量的基准（ＮＡ） 以０．０１２ｋｇ所含的碳原子数即阿伏加德罗常数作为物质的量的基准，其近似值为６．０２ × １０ｍｏｌ－１ ３．摩尔（ｍｏｌ） 摩尔是表示物质的量的单位．量度对象是构成物质的基本粒子（如分子、原子、离子、质子、中子、电子等）或它们的特定组合．例如：１ｍｏｌＦ，１ｍｏｌ ＣＯ，ａ ｍｏｌｅ，１．５ ｍｏｌ Ｎａ２ＣＯ３·１０Ｈ２Ｏ等． ４．摩尔质量（Ｍ） 单位物质的量的物质所具有的… 相似文献
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党怀民 《中学化学教学参考》1996,(4)
有机物燃烧耗氧规律小结甘肃省通渭县第一中学党怀民１．等质量的烃完全燃烧时，消耗氧气的量决定于分子中氢原子的质量百分含量，含氢越高，耗氧越多。设烃的质量为ｍｇ，其中含氢量为ｘ％，因完全燃烧时１ｍｏｌ碳原子消耗１ｍｏｌ氧气，４ｍｏｌ氢原子消耗１ｍｏｌ氧气... 相似文献
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本实验采用累积给药法，以偏钒酸钠（ＮａＶｏ３）灌流蟾蜍心室肌条，观察ＮａＶｏ３对心室肌功能性不应期（ＦＲＰ）和兴奋性的影响。结果：１０—１６０μｍｏｌ·Ｌ－１浓度的ＮａＶｏ３不同程度地延长心室肌ＦＲＰ，当灌流液ＮａＶｏ３浓度为８０μｍｏｌ·Ｌ－１时，心室肌ＦＲＰ的廷长与对黑浓度呈现显茗性差异（Ｐ＜０．０５），ＮａＶｏ３浓度为１６０μｍｏｌ·Ｌ－１时，其差异更显著（Ｐ＜０．０１）。ＮａＶｏ３浓度为４０μｍｏｌ·Ｌ－１和８０μｍｏｌ·Ｌ－１时，显著提高心室肌的兴奋性。 相似文献
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以环氧氯丙烷与二甲胺为原料合成无氰电镀添加剂ＤＥ,其最佳合成条件为：环氧氮丙烷与二甲胺的原料配比为１．０～１．１／１．０（ｍｏｌ／ｍｏｌ）,环氧氯丙烷以一定速度滴加于二甲胺溶液中,反应初期温度低于４０℃,中后期温度低于９５℃,反应时间约为４小时。 相似文献
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在一定条件下,用硫代硫酸钠与硫酸反应,通过观察溶液浑浊出现所需时间的长短来说明浓度、温度对化学反应速度的影响。改进后的实验装置如图１所示。图１ 改进后的实验装置ａ．浓度对化学反应速度的影响。①取三支试管分别加入等体积的不同浓度的硫代硫酸钠溶液。１号试管：１０ｍＬ０．１ｍｏｌ／Ｌ硫代硫酸钠;２号试管：７ｍＬ０．１ｍｏｌ／Ｌ硫代硫酸钠加３ｍＬ水;３号试管：５ｍＬ０．１ｍｏｌ／Ｌ硫代硫酸钠加５ｍＬ水。②取三支滴管吸取等量的１∶５硫酸溶液后,插入上述三支试管内。③用手挤压加液控制杆,三支滴管中硫酸同时滴… 相似文献
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烃完全燃烧的一条规律李忠俊杜爱英李平规律：等质量的烃完全燃烧时,消耗Ｏ２的量决定于分子中氢元素的质量分数。推导：由烃完全燃烧的方程式可知：１ｍｏｌＣ原子消耗１ｍｏｌＯ２,４ｍｏｌＨ原子消耗１ｍｏｌＯ２。一定质量的烃完全燃烧时消耗Ｏ２的物质的量就可表示... 相似文献
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报道了一种基于用溶胶凝胶法固定ＨＲＰ的化学发光型Ｈ２Ｏ２传感器，此传感器用于流动注射化学发光分析体系，可实现对Ｈ２Ｏ２的在线检测，测定的线性范围为１０－２０００μｍｏｌ／Ｌ，检测限为１．２μｍｏｌ／Ｌ，１０次测定的ＲＳＤ为２．１％。 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