Cooperation in the spatial public goods game with the second-order reputation evaluation

The existence of reputation can significantly promote the level of cooperation within the human population. In the recent years, most of the researches were based on binary image score or first-order evaluation standard. In this paper, we propose a second-order reputation evaluation model, in which the individual's image score will change not only in accordance with his own strategy, but also the reputation value of neighbors. Individuals try to enhance their reputation to cooperate with the surrounding high-reputation individuals, and then becomes an influential individual in the population. The existence of this mechanism renders the individuals who at the edge of the clusters formed by the cooperators to rapidly accumulate their reputation values through the adoption of cooperative strategy, and then the cooperative strategy can be spread widely and rapidly in the whole population. Through extensive numerical simulations, it is clearly indicated that the population cooperation behavior will be obviously improved when the individual's influence factor becomes smaller or the reputation step length increases. The current results are further conducive to understanding the emergence of cooperation in many real world systems.     

五孔剪切相机在测量二阶微分场中的应用

提出了在使用五孔剪切相机研制二阶微分场时，通过采用两次全场滤波技术可消除夹在二阶微分条纹中的一阶微分条纹，从而使二阶微分条纹具有较高对比度。     

Effect of magnetic-field-induced torsion on neutrinos and supernova collapse

Summary The neutrino emission from supernova 1987A is being studied by taking into consideration the effect of the magnetic field present in the star. The magnetic field generates an anisotropic feature in the local space-time, which in turn leads to the cancellation of the axial-vector part of the neutrino current. The interaction cross-section of these neutrinos in the course of their interaction with matter on Earth has an inverse square energy dependence. The present work presents the calculations based on this changed cross-section that relates to predictions of the expected number of events at KAMIOKANDE on the basis of the Mont Blanc signal. It might be interesting to take a look into the implications of these results. The author of this paper has agreed to not receive the proofs for correction.     

Is there a photon excess or photon deficit in the cosmic events?

Summary Bjorken predicted in the recent past about the large excess emission of photons in high-energy collisions and this was subsequently corroborated by some experimentalists as well. Obviously, this phenomenon is just opposite in nature to pro-centauro events marked by the production of photonless hadrons. In this note we will try to trace the outlines of this confusing and contradictory situation, probe quantitatively into this excess emission of photons (called progammaisation events) and compare them mainly with Bjorken's disoriented-chiral-condensate (DCC) model.     

双生子佯谬的投影诠释

在表示洛伦兹变换的复平面上,考察各边平行于坐标轴的直角三角形,以其中各边比例关系为“投影关系”,用于简明地诠释双生子佯谬的实质,并得出某种程度的一般性结论     

Classical Limits of Euclidean Gibbs States for Quantum Lattice Models

Models of quantum and classical particles on a lattice ^d are considered. The classical model is obtained from the corresponding quantum model when the reduced mass of the particle m = / #x210F;² tends to infinity. For these models, the convergence of the Euclidean Gibbs states, when m + , is described in terms of the weak convergence of local Gibbs specifications, determined by conditional Gibbs measures. In fact, it is shown that all conditional Gibbs measures of the quantum model weakly converge to the conditional Gibbs measures of the classical model. A similar convergence of the periodic Gibbs measures and, as a result, of the order parameters, for such models with pair interactions possessing the translation invariance, has also been shown.     

用图形计算器和CBL系统测量物体间的静摩擦力

介绍图形计算器。CBL及力传感器。并用于测量两物体同的最大静摩擦力。     

中心力场中散射角的简洁推导

本文从牛顿方程及角动量守恒定律出发 ,利用矢量函数的微积分运算技巧简捷地推导出中心力场中散射角 φ,避免了经典教科书中从轨道方程出发推导出 φ的繁琐性 ,不仅计算简洁 ,而且物理过程明确 .     

Near-field effect in optics of small objects composed of dipole atoms

A self-consistent problem of interaction of two dipole atoms separated by an unrestricted distance with the field of a quasi-resonance light wave was solved on the assumption that the investigated atoms are Lorentz linear oscillators and the polarizing fields inside the system consist of the Coulomb and the retarded parts. The solution obtained was investigated for the case where the atoms have the same polarizability and the distance between them is much smaller than the length of the external light wave. Formulas for the electric fields inside a small object and outside it have been obtained. It is shown that inside a small two-atom object there can take place longitudinal and transverse optical vibrations accompanied by corresponding dispersion effects depending on the interatomic distance and the angle between the axis of the system and the direction of propagation of the external light wave. The field outside the small object in the wave zone is linearly polarized when the external wave has linear polarization. However, the direction of polarization of the corresponding waves is largely determined by their frequency. It is also shown that the amplitude of the field outside the small object in the wave zone depends greatly on the frequency of the external field and the interatomic distance. The effects observed are considered as a near-field effect in optics of small objects. This phenomena makes it possible to investigate the structure of small objects with the use of optical radiation. Ul'yanovsk Branch of the Institute of Radio Engineering and Electronics, Russian Academy of Sciences, 48 Goncharov Str., Ul'yanovsk, 432700, Russia; e-mail: gadomsky@quant.univ.simbirsk.su. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6, pp. 765–770, November–December, 1999.