Intermittency Growth in Fluid Turbulence

Measurement and phenomenological analyses of intermittency growth in an experimental turbulent pipe flow and numerical turbulence are performed, for which working definitions such as degree, increment, and growth rate of intermittency are introduced with the help of quasiscaling theory. The logarithmic-normal inertial scaling model is extended to quasiscaling as the second-order truncation of the Taylor expansion and is used for studying the intermittency growth problem. The extended self-similarity properties are shown to be not consistent with the monotonicity of the third order local quasiscaling exponent and the nonmonotonic behaviour of the intermittency growth rate as a result of bottleneck. Digestions of the results with scale-dependent multifractals are provided.     

Stopband Phenomena in the Passband of Left-Handed Metamaterials

Stopband phenomena are reported in the passband of left-handed metamaterials. The samples with linear defect are designed by removing one layer of split ring resonators （SRRs）. It is shown that the left-handed transmission peaks have a distinct transform with the relative deviation of the SRRs centre from the wire centre 8, from a single left-handed peak, double left-handed peaks with different magnitude to no transmission peak, i.e. left-handed properties of metamaterials disappear. Numerical simulation shows that the change of 8 makes the effective permeability shift at a frequency range, where stopband occurs. It is thought that the stopband in left-handed passband is due to the symmetry breaking between SRRs and wires in the metamaterials.     

从弹簧滑块到地震预测:BK模型今昔谈

Burridge-Knopoff弹簧－滑块模型作为一个概念性的地震模型，自1967年提出以来一直为地震学家和物理学家所关注，对BK模型的研究成为物理学与地震学之间的一个活跃的交叉领域，BK模型的一些性质，例如确定性浑沌，自组织，孤立波，等等，能够为理解地震的性质和解决地震预测问题提供有用的线索，BK模型与目前的一些悬而未决的复杂性物理问题的联系，使它不仅对地震研究，而且对更普遍的多体系统问题的研究，都有重要的影响。     

NIR FT－Raman研究铝酸钠溶液的碳酸化过程

本文用ＮＩＲＦＴ－Ｒａｍａｎ光谱仪原位跟踪了铅酸钠溶液的碳酸化过程，观察到此过程的Ｒａｍａｎ光谱呈现振荡现象和非重线性，认为在碳酸化过程中，可能产生Ａｌ２（ＯＨ）离子和进一步缩聚形成的离子。     

非线性电路振荡周期分岔及费根鲍姆常数的测量

设计一种实验装置 ,能显示非线性电路中振荡周期分岔与混沌现象 ;同时 ,测出了该实验装置非线性电阻的伏安特性 ;利用该装置介绍一种测量费根鲍姆常数 (Feigen baumConstant)的方法     

喹诺酮类药物的质子化作用及互变异构现象与荧光特性的相关性研究

研究了不同酸碱条件下8种喹诺酮类药物的荧光特性,发现了在不同PH介质中喹诺酮类药物的荧光波长和荧光强度的变化规律,并对喹诺酮类药物质子化作用及互变异构现象与荧光性质的相关性进行了考察,确定了不同酸碱条件下的两种发光形体,进而对相应的变化机理进行了探讨。     

杨氏双缝干涉实验中的光谱奇异现象

基于部分相干光的传输理论,研究了杨氏双缝干涉实验中的光谱奇异现象。发现在杨氏双缝干涉实验干涉场区中的某个点的光谱奇异现象,它会随着某些参量(如源光谱宽度Γ′,缝宽参量ε,相对空间相干度Δ0)的变化而改变,指出该现象可应用于信息的编码及自由空间的信息传输。     

Field Quantization and Spontaneous Emission in Left-handed Material

Recently, research on left-handed materials （LHMs） has attracted considerable attentions. The LHMs are a kind of man-made metameterials which have negative permittivity and negative permeability. These metameterials have many novel properties such as inverse light pressure, and reverse Doppler effect, which lead to many potential applications of LHMs such as superlenses which, in principle, can achieve arbitrary subwavelength resolution. However, though the properties mentioned above are seen to be classical, the quantum phenomena in LHMs have also attracted attentions such as the modified spontaneous emission of atoms in LHME.     

Focusing of Surface Acoustic Wave on a Piezoelectric Crystal

We investigate the focusing phenomena of a surface acoustic wave （SAW） field generated by a circular-arc interdigital transducer （IDT） on a piezoelectric crystal. A rigorous vector field theory of surface excitation on the crystal we developed previously is used to evaluate the convergent SAW field instead of the prevalent scalar angular spectrum used in optics. The theoretical results show that the anisotropy of a medium has great impact on the focusing properties of the acoustic beams, such as focal length and symmetrical distributions near the focus. A dark field method is used in experiment to observe the focusing of the SAW tield optically. Although the convergent phenomena of SAW field on the anisotropic media or piezoelectric crystals are very complicated, the experimental data are in agreement with those from the rigorous theory.     

关于“莱顿瓶电震实验”的两点质疑

在人教版高中《物理.选修1-1》第一章第四节"电容器"中,为了引入电容器这个电器元件,教材首先讲述了1748年在巴黎圣母院前由物理学家诺莱特(A.J.A.Nollrt,1700～1770)表演的一个"魔术".教材表述如下:"魔术师"诺莱特调来700个修道士,让他们手拉手站成一排,全长约300m,