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<Time/Telegraph/DailyMail/SciAlive>: 姆潘巴佯谬三要素
热度 1 ecqsun 2013-11-2 13:50
News-Water.docx Mpemba Paradox Revisited -- Numerical Reinforcement. http://arxiv.org/abs/1312.1014 自从亚里士多德注意到有时热水比冷水结冰快至今已有 2350 多年的历史。坦桑尼亚一位名叫姆潘巴的中学生在 1963 年制作冰淇凌时进一步确认,并以其姓命名。姆潘巴效应是科学界的十大著名佯谬之一。因为此实验不易重复也有人认为是骗局。 2012 年英国皇家化学学会悬赏一千英镑求解并收到两万两千多份答卷,均考虑外在因素。其中获奖作品解释此现象为热对流所致。 其它解释包括热梯度、 eddy 流、过冷、杂质、等。 已建立的理论和计算表明此现象的内秉控制因素为热源的反常能量喷射方式和液体内的热导梯度,其外秉因素为环境的温度梯度。前两者皆由氢键 (O:H-O) 在受冷和变配位时的反常弛豫决定。结果证明能量释放速率(半衰期)与储能历史和热源所处环境相关。这一现象仅在高度非绝热(释放的能量即时被吸收)系统内发生。 一般来说,加热通过拉伸原子之间的键长存储能量 。但是,水加热会通过拉伸 O:H 并同时压缩 H-O 键而存储能量。倘若快速冷却, O:H-O 键会以指数的速率释放能量,此即姆潘巴现象之源。分子近邻配位的不均匀造成液体内比热和热导梯度,造成高温水的表体温差比低温水的表体温差大,而利于热传导。散发的热量必须及时吸走,否则观测不到此现象。 此即姆潘巴佯谬三要素。 声明: 本组近日将论文初稿上载到ArXiv(物理),并没有期望得到编辑和记者的青睐,竟掀起如此广泛的关注和讨论。就目前结果作出任何证据不足的结论为时尚早。 深入研究正在进行,期待中。 -多谢关注和有益的讨论!谨记下列来源 是 以 为 勉! 参考资料来源 Reddit: Comments http://www.reddit.com/r/Physics/comments/1plzfa/why_hot_water_freezes_faster_than_cold_physicists/ http://www.godlikeproductions.com/forum1/message2398229/pg1 http://www.reddit.com/r/science/comments/1pllek/why_hot_water_freezes_faster_than_coldphysicists/ Share statisitcs: http://www.viralnewschart.com/ShowLink.aspx?linkId=17606454 http://www.trendolizer.com/trend/Mpemba%20Effect Other sources: http://cr4.globalspec.com/blogentry/23577/We-ve-Finally-Figured-Out-Why-Hot-Water-Freezes-Faster-Than-Cold http://newstrackindia.com/newsdetails/2013/11/03/83-Why-cold-water-freezes-slower-than-hot-.html Why Hot Water Freezes Faster Than Cold, Explained http://www.medindia.net/news/why-hot-water-freezes-faster-than-cold-explained-127281-1.htm?utm_source=feedburnerutm_medium=feedutm_campaign=Feed%3A+allhealthnews+(Medindia+Health+News)#ixzz2jfhX4F8c http://www.buzzfeed.com/kellyoakes/9-things-scientists-just-dont-know
个人分类: 水之魂|3664 次阅读|1 个评论
Two Truths to Live By(转载)
hpeng1985 2010-1-1 13:41
Two Truths to Live By Hold fast, and let go:understand this paradox, and you stand at the very gate of wisdom Alexander M. Schindler The art of life is to know when to hold fast and when to let go.For life is a paradox:it enjoins us to cling to many gifts even while it ordains their eventual relinquishment. The rabbi of old put it this way: A man comes to this world with his fist clenched, but when he dies, his hand is open. Surely we ought to hold fast to life, for it is wondrous, and full of a beauty that break through every pore of Gods own earth. We know that this is so, but all too often we recognize this truth only in our backward glance when we remember what it was and then suddenly realize that it is no more. We remember a beauty that faded, a love that waned. But we remember with far greater pain that we did not see that beauty when it flowered, that we failed to respond with love when it was tendered. A recent experience re-taught me this truth. I was hospitalized following a severe heart attack and had been in intensive care for several days. It was not a pleasant place. One morning , I had to have some additional tests. The required machines were located in a building at the opposite end of the hospital, so I had to be wheeled across the courtyard on a gurney. As we emerged from our unit, the sunlight hit me.Thats all there was to my experience. Just the light of the sun.And yet how beautiful it was-how warming, how sparkling, how brilliant! I looked to see whether anyone else relished the suns golden glow, but everyone was hurrying to and fro, most with eyes fixed on the ground.Then I remembered how often I, too, had been indifferent to the grandeur of each day, too preoccupied with petty and sometimes even mean concerns to respond to the splendor of it all. The insight gleaned from that experience is really as commonplace as was the experience itself: life's gifts are precious-but we are too heedless of them. Here then is the first pole of lifes paradoxical demands on us: Never too busy for the wonder and the awe of life. Be reverent before each dawning day. Embrace each hour. Seize each golden minute. Hold fast to lifebut not so fast that you cannot let go.This is the second side of lifes coin, the opposite pole of its paradox: we must accept our losses, and learn how to let go. This is not an easy lesson to learn, especially when we are young and think that the world is ours to command, that whatever we desire with the force of our passionate being can, nay, will be ours.But then life moves along to confront us with realities, and slowly but surely this second truth dawns upon us. At every stage of life we sustain losses-and grow in the process.We begin our independent lives only when we emerge from the womb and lose its protective shelter. We enter a progression of schools, then we leave our mothers and fathers and our childhood homes. We get married and have children and then have to let them go. We confront the death of our parents and our spouses. We face the gradual or not so gradual waning of our own strength. And ultimately, as the parable of the open and closed hand suggests, we must confront the inevitability of our own demise, losing ourselves, as it were, all that we were or dreamed to be. But why should we be reconciled to lifes contradictory demands? Why fashion things of beauty when beauty is evanescent? Why give our heart in love when those we love will ultimately be torn from our grasp? In order to resolve this paradox, we must seek a wider perspective, viewing our lives as through windows that open on eternity.Once we do that, we realize that though our lives are finite, our deeds on earth weave a timeless pattern. Life is never just being. It is a becoming, a relentless flowing on. Our parents live on through us, and we live on through our children. The institutions we build endure, and we will endure through them. The beauty we fashion cannot be dimmed by death. Our flesh may perish, our hands will wither, but that which they create in beauty and goodness and truth lives on for all time to come. Dont spend and waste your lives accumulating objects that will only turn to dust and ashes.Pursue not so much material as the ideal, for ideals alone invest life with meaning and are of enduring worth. Add love to a house and you have a home. Add righteousness to a city and you have a community. Add truth to a pile of red brick and you have a school. Add religion to the humblest of edifices and you have a sanctuary. Add justice to the far-flung round of human endeavor and you have a civilization. Put them all together, exalt them above their present imperfections, add to them the vision of humankind redeemed, forever free of need and strife and you have a future lighted with the radiant colors of hope.
个人分类: 英语拾趣|3199 次阅读|0 个评论

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