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郴州做包皮手术哪好郴州包皮长手术This is our planet, the Earth.这是我们的行星:地球It is an remarkable, ever-changing world, full of natural wonders.这是一个神奇的千变万化的世界 充满着各种自然奇观But there#39;s more to Earth than this, much more.但是地球本身还有比自然景观更奇特的东西Because our planet is unique in the solar system,因为我们的行星在整个太阳系是独一无二的Perhaps even in the universe.甚至在整个宇宙也是如此4.5 billion years have made it a world of extraordinary landscapes45亿年的时光地球形成了独特的风景地貌and a home to life.成了适宜人类生存的家园My name is Iain Stewart.And I want to show you我叫伊恩·斯图尔特 我将向您介绍how our planet works.我们美妙的星球的运行原理I#39;m going to explore volcanoes.我将从火山开始讲起They#39;re terrifyingly destructive.火山具有极大的破坏力But they#39;re also the most fundamentalforce on the planet.但是它们仍然是地球上最根本的自然力量Volcanoes are part of a global system that continually reshapes our world火山是地球系统的一部分它们一直在改变着地貌They hold the key to the origins of life on Earth.火山在很大程度上决定了地球的生命起源They saved the planet from possibly the biggest crisis it#39;s ever faced.在地球面临最大危机的时候是火山拯救了地球And they#39;ve even formed a partnership with life它们甚至和生命相互依存that keeps our planet habitable.给地球生物提供了适宜生存的环境 Article/201508/390763郴州治疗龟头炎哪家医院最好 HK chief: Ready to discuss electoral reform香港特首表示准备好讨论选举改革Hong Kong#39;s Chief Executive Leung Chun-ying says authorities are y to hold talks with anyone on the issue of Hong Kong#39;s electoral reform.香港特首梁振英表示就香港选举改革问题当局已准备好与任何个人或团体进行讨论。But the chief executive stressed that any proposed change must adhere to the Basic Law and the decision made by the National People#39;s Congress Standing Committee.但梁表示任何改革都必须遵守《基本法》和全国人民代表大会常务委员会的决定。Speaking during a visit to Huizhou in China#39;s southeastern Guangdong Province, Leung said that any reform that does not conform with the Basic Law and the NPC standing committee#39;s decision would be unrealistic.在访问中国东南部广东惠州时,特首表示不符合《基本法》和全国人大常委会决定的任何改革都是不可能实现。He pointed out that every society#39;s electoral system must be created and amended in line with its constitutional document, which in Hong Kong#39;s case is the Basic Law.他指出每一个社会选举制度的创建和修改都必须符合其宪法,而香港就是要贯彻基本法。 Article/201412/347050One of the fundamental principles in modern physics is that there#39;s no absolute time.And I#39;m not not even talking about relativity making time go at different rates.if you#39;re going near light sead,I just mean that any time is as good as any other to set your clock to zero,The predictions of physics work all the same,and it#39;s not like there#39;s some ;absolute starting time;. I mean,if there were,time zones wouldn#39;t work,In addition to allowing time zones,the fact that there#39;s no absolute time,also implies the law of conservation of energy.“绝对时间不存在”是现代物理基本定理之一,我说的不是接近光速时,相对论使得,时间流逝速率不同,我是说,在任意时间将时钟归零都一样,物理所做的预测完全相同,“绝对开始时间”这种东西并不存在,如果有的话,那么时区就无效了,除时区之外“绝对时间不存在”也暗示着能量守恒定律。Here#39;s simple proof to show that if a force doesn#39;t depend explicitly on time,then that force conserbes energy! First conserving energy just means that there#39;s a certain number,called the energy,which doesn#39;t change as time passes.If you compare the energy at two different times,you#39;ll see no difference.And the total energy of a system isthe sum of its energy of motion,or kinetic energy,and its energy due to position-the potential energy,So all we need os to find the change in kinetic and potential energiesover time.and add them up!这里简单明下,若外力不显式地依赖于时间,那么该力储存能量,首先,储存能量仅意味着有一个可称为“能量”的解切数字,不随时间变化,如果你在两个不同时间比较它们也不会看到区别,系统的总能量为其运动的能量,或动能,加上由位置决定的热能之总和,我们要找的就是动能和势能随时间的改变量,把它们相加。Ok,we know the kinetic energy of an object is half of its mass times its velocity squared,So the change in kinetic energy over time is just,one half m times the differenceof the squares of the velocities,Some clever algebra can rearrange this expression to become,the average velocity times m times the CHANGE in velocity,But a change of velocity over time is just an acceleration,and mass times acceleration is equal to the force on the object,So the change in kinetic energy of an object over time is just velocity times force.好了,我们知道物体的动能为1/2物体质量乘经速度平方,那么,动能随时间的变化就是,1/2.m(物体质量).速度改变量平方,机智的代数变化可将此表达式变为,平均速度.m(质量).速度改变量,不过,速度随着时间的改变量就是加速度,质量乘以加速度等于施加在物体上的力,那么,物体动能随时间的改变量就是速度乘以力。On the other hand,the change in the potential energy of an object ,is negative the amount of work it takes to get the object to its current position form its previous position independent of the path taken,that is,potential energy is the negative of the foece applied times the change in position,This is where the ;there#39;s no absolute time;part comes into play,You can#39;t have potential energy for a force that changes over time,And just to be clear, ;no changing over time; doesn#39;t mean that,an object can#39;t experience a changing force along the course of journey,the foece might be different at different places,but at any particular place.the force must remain the same.另一方面,物体势能的改变量,为将物体从原先位置带到现在为止所需的功的负值,与所选取路径无关,即,势能等于物体所受力乘以位置变化量之积取负值,现在“绝对时间不存在”可要掺合进来啦? 随时间变化的力不可用势能衡量,这里要说清楚“不随时间改变”,不是说,物体在运动过程中不可能受到变力作用,不同地点力的大小也许不同.但在某一处,力一定是相同的(包括大小和方向)。Anyway,this is all just to say that the change in potential energy is negative F times the change in position.The negative comes from the fact that if you let the force push you along,your potential energy decreases,while if you fight in opposition to the force your potential energy increases.So the change in potential energy over time is the negative of the force times the change in position over time,but change in position over time is velocity!无论如何,这只说明势能改变量为,负的F(力的大小)乘以位置变化量,有负号是因为,如果你让这个力一直推着你,你的势能就会降低,而当你反抗该力而行,你的势能会增加,因此,势能随时间的改变量,就是负的力的大小乘以一段时间内位置变化量,但一段时间内位置变化量就是速度。Which means change in potential energy of an object over time is negative velocity times force.And thus the change in the total energy over time,which is the sum of the changes in the kinetic and potential energies over time,is v*F plus negative v*F,which equals zero!And zero change in energy over time is precisely conservation of energy!All for the same reason that time zones work.也就是说,一段时间内的势能改变量就是负的速度乘以力,因此,一段时间内总能量的改变量,即动能和势能随时间的改变量之和,就是V*F(-(V*F))等于0,能量随时间改变量为零正是能量守恒,同样理由也适用于时区。 Article/201505/373538郴州公立医院哪个治疗性病最专业

郴州有什么好方法治疗龟头炎As they grow bigger and bigger,随着体积越来越大they start to spin and throw out a disk of debris它们开始旋转,甩出的碎屑形成盘状that will coalesce to form a solar system.在日后融合形成太阳系This kind of process is exactly the kind of process我们的太阳系that would have formed our solar system.就是这样形成的When we look at our solar system,在我们太阳系中all of the planets rotate around the sun in the same direction所有行星都以相同的方向绕着太阳旋转and they all are in the same plane而且都位于相同平面the same flat sheet around our sun,在相同的平面上绕着太阳旋转and this is exactly a consequence of the fact这是因为早期that the early solar system formed out of a broad disc.太阳系是在一个广阔的圆盘上形成的With the solar-system in place太阳系就定位之后all that is left is for the young star to light up.就等年轻的恒星开始发光When it happens it is sudden and irreversible.这个现象来得又快又急而且无法逆转Ultimately the process starts这个过程终究会发生and because it liberates so much energy with that first fusion,因为第一次融合会释放出惊人的能量then the process takes off.整个过程便一发不可收拾Um - it lights up a large area and it starts to shine on its own它照亮广阔区域within a matter of minutes.在短短几分钟内便开始自行发光It#39;s a very quick process.这个过程很快In that first burst of light the star在第一波猝发的光线中has begun its lifelong activity as a factory恒星展开制造for making other chemical elements.其他化学元素的生涯Every atom in everything around us was made in the heart of a star我们周遭的一切原子都来自恒星的核心and all were made from the same starting ingredient.而且起始成分都一模一样The simplest element that we have is hydrogen宇宙间最简单的元素是氢and it#39;s actually the building block它是所有for all the other elements that we have.其他元素的基础材料In the heart of the sun hydrogen nuclei氢原子核也就是质子protons - are stuck together to make heliumlt在太阳的核心结合形成氦It sounds straightforward这听起来很简单but it can only happen in the most extreme conditions.但却只能发生在最极端的情况下In order for these protons to come together,质子要两两结合的话…because they#39;re both positively charged因为它们都带正电they don#39;t want to come together,所以会互相排斥they#39;ve actually got to be pushed together.必须要有外力压迫才行In order to do this you need very high temperatures所以需要很高的温度so they#39;re moving very fast and you also need very,让它们快速移动very high pressures.也需要极高的压力The only part of the sun that is hot and dense enough is the core.太阳唯一够热,密度够高的地方An area that contains over half the star#39;s mass就是它的核心in less than 2 percent of its volume.太阳核心的体积不到太阳的2%Here at 15 million degrees the protons但质量却超过太阳的一半are bashed together so hard that they fuse.质子在一千五百万度的高温下猛然撞击、融合A helium nucleus is a tiny bit lighter氦原子核虽然由四个质子形成than the combined mass of the 4 protons it is made from.但重量却比四个质子轻一点And as Einstein tells us it is爱因斯坦告诉我们太阳的能量that tiny bit of lost mass that provides the power.来自这一点点流失的质量Energy is equal to mass times the speed of light,能量等于质量乘以times the speed of light.光速的平方 Article/201504/367805郴州男科病医院 Macao makes great strides since return to China in 19991999年回归以来取得的进步December 20th, or Saturday this week, will mark the 15th anniversary of Macao#39;s return to China.本周六的12月20日是回归祖国的第15个周年纪念日。 Article/201412/349232郴州治疗前列腺炎权威医院

郴州性功能障碍医院栏目简介:《趣味青春英语视频》是外语网络电台的精品节目,通过大讲堂的网络课堂形式,能够帮助英语学习者积累一些英语背景知识,并通过互动的教学形式,帮助有效记忆英语知识。本栏目是学习趣味青春英语的好材料。 Article/201510/398745 Holiday tourists revel in the beauty of nature国庆长假游人沉醉于大自然美景The National Day holiday has offered Chinese seven days off work to explore the beauty of nature across the country. 国庆的7天长假为国人提供了外出欣赏祖国大好美景的机会。Here are some beautiful places you won#39;t want to miss during autumn, known as the golden season.以下就是你不想错过这个以“黄金季节”著称的金秋时节的美丽景区。 Article/201410/335415郴州检查睾丸多少费用郴州市东方医院男科专家挂号



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