中微子及中微子实验的最新成就

本文从中微子的泡利假设到实际探测到中微子的几个重要实验,全面介绍了中微子及中微子实验的最新成就。由于2002年诺贝尔物理奖获得者雷蒙特·戴维斯(RmymondDavisJr)和小柴昌俊(MasatoshiKoshiba)在中微子探测研究方面所做的卓越贡献,中微子实验所开创的中微子天文学正处在21世纪科学研究的一个前沿。     

中微子和超光速现象的可能性

如果中微子静止质量不为零,那么为了解释宇称不守恒的二分量中微子理论就要求中微子是超光速的。讨论了在相对论框架内对这种超光速现象的理解,以及存在"快子"的可能性。     

Chemical oscillations

A chemical reaction is usually thought of as coming together of reactant molecules to form products. The concentrations of initial components (reactants) decrease, and concentrations of products increase until they reach a well defined state: the equilibrium. This process is accompanied by a decrease of the system free energy (compared at constant pressure and temperature), until it reaches a minimum in the equilibrium. Thus, it follows from the nature of the law of mass-action that every simple reaction approaches its equilibrium asymptotically, and the evolution of any physico-chemical system leads invariably to the steady state of maximum disorder in the universe. Normally, chemical systems approach equilibrium in a smooth, frequently exponential relaxation. Under special circumstances, however, coherent behavior such as sustained oscillations are observed and the oscillations of chemical origin have been present as long as life itself. Such reactions can be studied using mathematical models, the Lotka-Volterra model being the earliest and the simplest one.     

Chemical oscillations

The law of mass-action led chemists to the belief that reactions approach equilibrium steadily. So the discovery of chemical oscillations came as a surprise. Now chemists are very familiar with reactions that oscillate in time and/or space. Experimental and theoretical studies of such reactions showing temporal and spatial oscillations attract the interest of many laboratories world-wide. The Lotka-Volterra model is the simplest mathematical model which exhibits such oscillations. In this article, we use this model to illustrate chemical oscillations with the help of a computer program.     

大气中微子vμ振荡几率估算

据高能中微子的"长基线”实验计设参数,用数值实验常数相关联的唯象方法算出中微子质量数值,估算了中微子振荡几率,判断了μ中微子vμ与τ型中微子vτ最可能发生振荡.     

De Broglie-Ross模型和太阳中微子问题

基于已知的 Ｄｅ Ｂｒｏｇｌｉｅ模型和 Ｒｏｓｓ模型结合的太阳中微子新模型,可以获得两个中微子合成一个光子及其能量公式。由此能解释太阳中微子的下列三个观察结果;仅检测到理论预测值的三分之一;太阳活动和中微子流间存在反相关关系并与观察到的光子释放率一致。     

为大亚湾实验室新中微子振荡建造刻度系统

今年3月8日大亚湾中微子实验国际合作组发言人、中科院高能物理研究所所长王贻芳在北京宣布,大亚湾中微子实验发现了一种新的中微子振荡(图1),并测量到其振荡几率(图2)。该发现被认为是对物质世界基本规律的一项新的认识,     

When Energy Conservation Seems to Fail: The Prediction of the Neutrino

A historical case study concerning the serious doubts that arose in early 1930s about the validity of the law of energy conservation in nuclear disintegrations, and the hypothesis of neutrino, will be closely analyzed with the goal of promoting understanding of the nature of science. This work is based upon primary archival and printed sources, with a particular focus on the proceedings of the first International Conference of Nuclear Physics which was held in Rome on October 1931.     

超流物质非平衡直接Urca过程的反应率与中微子辐射率

在中子星的热演化过程中,直接Urca可能是非平衡的.本文计算并讨论了各种核子超流存在时对非平衡直接Urca过程净反应率和中微子辐射率的影响,发现当化学偏离量超过一定值的时候,净反应率和中微子辐射率会迅速增强,根源可能在于化学偏离量足够大会破坏超流Cooper对.     

用输入-输出线性化控制混沌振动

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｉｎｒｅｃｅｎｔｙｅａｒｓ ,ｃｏｎｔｒｏｌｌｉｎｇｃｈａｏｓｈａｓｄｒａｗｎｇｒｅａｔａｔｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｉｔｓｔｈｅｏｒｅｔｉｃａｌｉｍｐｏｒｔａｎｃｅａｎｄｐｏｓｓｉ ｂｌｅａｐｐｌｉｃａｔｉｏｎｓ[1,2 ] .Ｔｈｅａｐｐｌｉｃａｔｉｏｎｓｏｆｎｏｎｌｉｎｅａｒｓｙｓ ｔｅｍｔｈｅｏｒｙｔｏｃｏｎｔｒｏｌｃｈａｏｓｉｓｏｎｅｏｆｔｈｅｍａｉｎａｓｐｅｃｔｓｏｆｒｅｓｅａｒｃｈｏｎｃｏｎｔｒｏｌｌｉｎｇｃｈａｏｓ[2 ] .Ｔｈｅｅｘａｃｔｌｉｎｅａｒｉｚａｔ…     

为大亚湾实验室新中微子振荡建造刻度系统(续)

<正>我国大亚湾核实验室就是在寻找第三种振荡。参与这项研究的上海交通大学中微子团队以刘江来和李高嵩、顾文强两位博士研究生组成。他们参加了实验安装、调试、取数和物理分析各阶段工作(图7),为取得这一世界性成果作出了重要贡献。     

非兴奋型生物细胞内钙离子浓度振荡的数值仿真

针对描述一类非兴奋型细胞,如肝细胞或上皮细胞内钙振荡的Marhl-Haberichter及其简化数学模型,数值仿真了在不同参数条件下,系统呈现的不同类型的复杂钙振荡模式。得到了非兴奋型生物细胞的四类钙振荡形式：点-点型周期簇振荡、点-环型周期簇振荡、点-环型双节律簇振荡及混沌簇振荡。应用快慢动力学分岔分析方法,研究了点-点型周期簇振荡产生的动力学性质。     

Conductance oscillations through an aharonov-bohm ring with a quantum gate

１　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｑｕａｎｔｕｍｃｏｈｅｒｅｎｔｔｒａｎｓｐｏｒｔｉｎｍｅｓｏｓｃｏｐｉｃｓｙｓｔｅｍｈａｓｂｅｅｎｉｎｖｅｓｔｉｇａｔｅｄｅｘｔｅｎｓｉｖｅｌｙｉｎｔｈｅｐａｓｔｄｅｃａｄｅ．Ｍｏｔｉｖａｔｅｄｂｙｓｏｍｅｒｅｃｅｎｔｅｘｐｅｒｉｍｅｎｔｓ,ｍａｄｅｂｙＹａｃｏｂｙｅｔａｌ．［１］ａｎｄＢｕｋｓｅｔａｌ．［２］,ｐｈａｓｅｓｅｎｓｉｔｉｖｅｔｒａｎｓｐｒｏｔｉｎａｎＡｈａｒｏｎｏｖｂｏｈｍ（ＡＢ）ｒｉｎｇｗｉｔｈａｑｕａｎｔｕｍｄｏｔ（ＱＤ）ｅｍｂｅｄｄｅｄ…     

Aharonov-Bohm环中磁场调制的极化电导振荡

Oscillations of the spin-polarized conductance controlled by a uniform magnetic field in a modified Aharonov-Bohm ring is studied with use of one-dimensional quantum wave guide.Its expression at zero temperature is obtained as a function of the flux penetrating the ring and the magnetic field.It has been found that there are two kinds of polarized conductance extremas for a given Fermienergy.As Zeemann energy of spin-polarized electron in the stub is varied.one kind of extrema exhibits continuous phase shift .However,another is locked at particular values of phase shift and it can only change abrouptly from a maxima to a minima when Zeemann crosses the level of the bound state of isolated stub.This is a different mehanism for abrupt change phase of conductance osillations.     

Torsional oscillations of a rigid disc bonded to multilayered poroelastic medium

INTRODUCTION The dynamic response of foundations resting onthe surface of a half space is of significant importancein soil-foundation interactions and machine founda-tion designs. Observation of earthquake damage in-dicated that the local soil properties, foundation ge-ometries, etc., play a central role in the dynamic be-havior of the soil-foundation system. Ever-increasing research has been devoted to theproblem of an elastic half space indented by a rigidfooting by employi…     

通过带有量子门的Aharonov-Casher环的自旋极化电导振荡

1 Introduction Since some experi ments made by Yacoby,et al.[1],and Schuster ,et al.[2],that first measured electrontransmission phase through a quantum dot ( QD) ,phase sensitive transports in open mesoscopic ringwith a QD have been extensively investiga…     

对流扩散方程GLxF格式数值解振荡可控性的又一证法

用修正方程分析方法证明了对流扩散方程GLxF格式数值解振荡的可控性,得到了与文献[1]的定理1相同的结果。     

A simple laboratory experiment for studying the relaxation oscillations in a diode laser

Conclusion We have demonstrated the modulation of laser around threshold for the observation of relaxation oscillations in a semiconductor diode laser. The oscillations frequency for the diode laser D₁ was 1.5 kHz whereas the oscillations frequency corresponding to the laser from laser pointer D₂ was 227 kHz. We have also observed the variation in damping time and relaxation frequency of both the lasers as a function ofx. In fact a classroom exercise can be taken up easily to do the parametric characterisation.