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新技术令我们可以观察到布朗运动爱因斯坦当年认为当时不可能实现的事情现在能实现了，科学家能利用超高速位置探测器和光阱捕捉到布朗运动的粒子图像。By holding a micron-sized sphere in a optical trap and measuring the scattered light with a high speed position detector (75MHz), a team was able to measure the motion of the sphe... 阅117 转1 评0 公众公开 11-04-11 13:28 |
Another detector may have seen a handful of dark-matter particles last year — although the experimenters dismiss them as background noise. And yet another experiment has found no evidence for dark matter at all.This sector could include multiple types of dark matter and a number of dark forces, which, like ordinary m... 阅93 转0 评0 公众公开 11-03-29 00:40 |
中国锦屏山暗物质探测地下实验室前几天我去参加了四川大学组织的暗物质理论和实验研讨会。会后，我也跟随部分与会代表一起前往锦屏山参观了锦屏山地下实验室，这个实验室是暗物质直接探测实验室。不过，就目前而言，被研究得最多也是最被看好的暗物质模型是所谓弱相互作用重粒子(Weakly Interacting Massive Particle, WIMP).这种粒子的特点是... 阅4180 转14 评0 公众公开 11-03-29 00:03 |
首份全球地表透水性图 第一次调查结果展示了全球地表岩层透水性的分布，从图中可以看出，总体上来说透水性能较高的区域占了较大比例，制作这张图的是加拿大范库弗的不列颠哥伦比亚大学水文地质学博士后托姆格里森。Gleeson says that is a significant omission, as the movements of groundwater could well affect regional climate:"Gr... 阅124 转0 评0 公众公开 11-02-21 14:42 |
Geomagic square: Inner cell missing In a geomagic square, each digit is replaced by a "polyomino" made up of different numbers of identical squares.Geomagic square: Corner cell missing A second normal geomagic square, this time the target is a 4 * 4 square missing one corner cell.Rare square In this geomagic... 阅1064 转4 评0 公众公开 11-01-27 21:39 |
欧拉分割函数理论成功解决分割函数p(n)是指一个整数能用自然数分拆表达的次数总和，例如3可以用"3，2+1，1+1+1"三种方法表示，因此p(3)=3；4可以用"4，3+1，2+2，2+1+1，1+1+1+1"五种表示，因此p(4)=5；...p(100) = 190569292...p(1000) = 24061467864032622473692149727991...Examples.分割函数是数论研究的核心问题之一... 阅218 转4 评0 公众公开 11-01-22 14:41 |
"Many problems we have today - including social and economic instabilities, wars, disease spreading - are related to human behaviour, but there is apparently a serious lack of understanding regarding how society and the economy work," says Dr Helbing, of the Swiss Federal Institute of Technology, who chairs ... 阅149 转0 评0 公众公开 10-12-31 17:42 |
Until quite recently, no-one knew whether Gombocs even existed.To give it its full mathematical description, a Gomboc is a three-dimensional, convex and homogeneous object with exactly one stable point of equilibrium and one unstable point of equilibrium.It''s easy to create a non-convex shape with one stable ... 阅867 转1 评0 公众公开 10-12-21 16:44 |
重點提要 ■在將愛因斯坦的重力與量子物理統合成單一萬有理論的過程中，霍金關於黑洞及宇宙起源的工作，或許是理論物理學家在該主題的成果裡最扎實的。在古典物理中，我們假設過去是一連串的事件，但在量子物理中，過去和未來一樣是不確定的，僅能以機率分佈的方式存在，即使是整個宇宙也沒有唯一的過去或歷史。所以量子物理和古典物理的實在性... 阅239 转10 评0 公众公开 10-11-14 23:16 |
LHC完成“迷你创世大爆炸”欧洲粒子物理研究所（CERN）11月8日宣布，大型强子对撞机（LHC）成功制造了一次"迷你创世大爆炸"。这次实验使用铅原子核进行对撞，产生的等离子状态和宇宙形成之初类似。铅离子对撞侧重研究宇宙形成过程，科学家将通过观察对撞产生的瞬间"夸克-胶子等离子态"来了解137亿年前宇宙形成的"大爆... 阅93 转0 评0 公众公开 10-11-09 14:02 |
