Reaction between alkyl isocyanides and isopropylidene Meldrum’s acid in the presence of bidentate nucleophiles

Summary The reaction between alkyl isocyanides and isopropylidene Meldrum’s acid in the presence of 1,2-ethanediol leads to N ¹-(alkyl)-2-(5,7-dioxo-1,4-dioxepane-6-yl)-2-methylpropanamides. 1,3-Propanediol or 1,4-butanediol produce hydroxyalkyl 1-(tert-butyl)-4,4-dimethyl-2,5-dioxo-3-pyrrolidinecarboxylates. When the reaction was performed in the presence of catechol, bis(2-hydroxyphenyl) 2-[2-(tert-butylamino)-1,1-dimethyl-2-oxoethyl]malonate was obtained. 2-Aminophenols react with alkyl isocyanides in the presence of isopropylidene Meldrum’s acid to produce 1-alkyl-N ³-(2-hydroxyaryl)-4,4-dimethyl-2,5-dioxo-3-pyrrolidinecarboxamides in good yields.     

Polarized proton target for RI Beam experiments

We have constructed a polarized proton solid target system for radioactive nuclear beam experiments at the Center for Nuclear Study, the University of Tokyo. The proton polarization is based on an electron population difference in a photo-excited triplet state of pentacene molecule. The target system was completed in 2003 and applied to a RI beam experiment in 2003 and 2005 by using the projectile fragment separator, RIPS at RIKEN. The maximum polarization reached 20% under the condition of T=100 K and B=0.09 T. Overview of the polarized target and its application in physics experiments at RIPS and RIBF of RIKEN are presented.     

A particular solution of Heun equation for Hulthen and Woods‐Saxon potentials

In this article a particular solution of Heun equation is derived by making use of the Nikiforov‐Uvarov (NU) method which provides exact solutions for general hypergeometric equation and eigenvalues together with eigenfunctions of the Heun equation for this particular solution are obtained. One to one correspondence (isomorphism) of the aforesaid equation with the radial Schrödinger equation is emphasized and also physical counterparts of the parameters in this equation are put forward by introducing solutions for two different potential functions (Hulthen and Woods‐Saxon potentials).

     

基于广义极值的混沌电场峰值分布研究

通过分析峰值分布及广义极值分布理论关于混沌电场峰值分布的特点,获得一种混沌电场峰值分布的计算方法,结合Bootstrap重采样技术,提出了混沌电场峰值分布参数估计方法,该方法吸取了重采样技术估计的优点,对分布参数置信区间的估计更为准确、实用。以蒙特卡罗仿真和某机械搅拌混响室内电场数据为实例,结果表明,与传统的正态近似法、百分位法、BC-t等方法相比,其计算结果与实际结果更为吻合,证明了该方法具有更高的准确度。     

Contact position and width effect of graphene electrode on the electronic transport properties of dehydrobenzoannulenne molecule under bias

By applying nonequilibrium Green?s function formalism in combination with density functional theory, we have investigated the electronic transport properties of dehydrobenzoannulenne molecule attached to different positions of the zigzag graphene nanoribbons (ZGNRs) electrode. The different contact positions are found to drastically turn the transport properties of these systems. The negative differential resistance (NDR) effect can be found when the ZGNRs electrodes are mirror symmetry under the xz midplane, and the mechanism of NDR has been explained. Moreover, parity limitation tunneling effect can be found in a certain symmetry two-probe system and it can completely destroy electron tunneling process. The present findings might be useful for the application of ZGNRs-based molecular devices.     

电磁驱动45钢准等熵压缩的实验研究

在已有的众多准等熵加载技术中,磁驱动准等熵加载技术具有准等熵程度高、压力范围大、实验材料种类多、效费比高等特点。利用中物院流体物理研究所建成的磁驱动准等熵压缩和高速飞片实验装置CQ-1.5(最高加载压力为50GPa),成功开展了45钢的准等熵压缩实验,对装置的主要参数进行了介绍;利用激光干涉测试系统DPS获得了45钢飞片的自由面速度历史,通过反积分处理给出了材料准等熵压缩的p-V关系。通过分析实验数据,获得了45钢3种形式的等熵方程的参数。实验获得的最高等熵压力为47.5GPa。     

Anomalous transport in fluid field with random waiting time depending on the preceding jump length

Anomalous (or non-Fickian) transport behaviors of particles have been widely observed in complex porous media. To capture the energy-dependent characteristics of non-Fickian transport of a particle in flow fields, in the present paper a generalized continuous time random walk model whose waiting time probability distribution depends on the preceding jump length is introduced, and the corresponding master equation in Fourier-Laplace space for the distribution of particles is derived. As examples, two generalized advection-dispersion equations for Gaussian distribution and lévy flight with the probability density function of waiting time being quadratic dependent on the preceding jump length are obtained by applying the derived master equation.     

A type of conserved quantity of Mei symmetry of Nielsen equations for a holonomic system

A type of structural equation and conserved quantity which are directly induced by Mei symmetry of Nielsen equations for a holonomic system are studied.Under the infinitesimal transformation of the groups,from the definition and the criterion of Mei symmetry,a type of structural equation and conserved quantity for the system by proposition 2 are obtained,and the inferences in two special cases are given.Finally,an example is given to illustrate the application of the results.     

Edge states at the interface between monolayer and bilayer graphene

The electronic properties for monolayer-bilayer hybrid graphene with zigzag interface are studied by both the Dirac equation and numerical calculation in zero field and in a magnetic field. Basically there are two types of zigzag interface dependent on the way of lattice stacking at the edge. Our study shows they have different locations of the localized edge states. Accordingly, the energy-momentum dispersion and local density of states behave quit differently along the interface near the Fermi energy EF=0.