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（第三、四章内容）完善与提高１．在室内将一支温度计从酒精中抽出，它的示数将先后．２．物态变化中，要放热的过程有．３．下列现象各属什么变化？①烧开水冒“白气”．②湿衣服变干③箱的形成④灯泡钨丝变细⑤焊接金属③吃冰棒解热４．下列说法正确的是。Ａ．固体都需达到一定温度才能熔化Ｂ．物体凝固时，温度一定要降低Ｃ．０℃的冰冷却比０℃水效果好Ｄ．吹风凉快，是因为把温度吹低了５．站在百米赛跑的终点的计时员，如果他听到枪声再计时，那么他开始计时的时间比实际起跑时间晚多少秒？初二物理知识明细表(二)@武东鸣 相似文献
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这里采用杨介信及张大刚、傅永祝的方法分别运用简式计时器、DIS数字化实验系统、同步电机进行实验．3种方法分别采用不同的计时方式．这些计时方式都具有相同级别的计时精度． 相似文献
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本文通过对2001—2007年电子计时系统在山东省体育高考中的应用研究,简要介绍了电子计时系统的工作原理及其特点,使广大考生及家长、教练员等清楚电子计时系统的操作流程,增加体育高考的透明度,为基层及其他体育场馆引进和使用电子计时系统提供参考。 相似文献
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基层田径运动会的径赛项目一般有：100米、200米、400米、4×100米接力、4×400米接力、100米栏、110米栏、800米、1500米、3000米和5000米。在运动会上一般安排17名或25名裁判员担任终点计时工作。在整个裁判过程中要求裁判员准确计时,不能弄虚作假。下面就计时长和计时员在运动会上所做的主要工作作一简要阐述。 相似文献
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脑成像与神经心理学的研究均提供了存在自动计时系统与控制计时系统的证据。对时间信息自动加工的研究表明,自动计时系统与运动系统关系密切,均包含小脑、基底神经节和辅助运动区。对时间信息控制加工的研究表明,包括背外侧前额叶皮质的额叶一纹状体回路为认知控制计时系统与工作记忆的基础,时间信息加工的注意调节系统较复杂,涉及区域主要包括前辅助运动区、右岛盖、顶叶、前扣带皮质。自动加工与控制加工并不是截然分离的,两个系统激活区域和激活强度存在差异,两个系统时间范围不存在清晰的分界点。 相似文献
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新型时钟芯片DS12C887具有计时精确、断电情况下运行十年以上不丢失资料等优点,在单片机计时系统中有着广泛应用。本文分析了DS12C887的功能特性,介绍了DS12C887与AT89C51单片机系统的硬件电路图．同时介绍了单片机应用程序的编写方法。 相似文献
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题目小强和小明多次进行百米赛跑，每次小强总比小明提前１０米到达终点．如果让小强后退到离起点１０米处，小明仍在起点赛跑，则：（）Ａ．他们同时到达终点；Ｂ．小强先到达终点；Ｃ．小明先到达终点；Ｄ．不能确定谁先到达终点．分析小强后退１０米和小明同时起跑，到达终点时，小强跑了１１０米，小明跑了１００米，判断他们谁先到达终点，可用他们所需时间的长短来比较．解析设小强跑完１００米所用时间为ｔ秒，则小强的速度是：v强=１００／ｔ米／秒．小强到达终点时，小明还落后１０米，即小明在ｔ秒内跑的距离是１００米一１０米＝… 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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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 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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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 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