Fundamental Groups of Graphs of Cyclic Subgroup Separable and Weakly Potent Groups

We give a characterization of the cyclic subgroup separability and weak potency of the fundamental group of a graph of polycyclic-by-finite groups and free-by-finite groups amalgamating edge subgroups of the form × D,where h has infinite order and D is finite.     

Nonlinear elastic constitutive relations of residually stressed composites with stiff curved fibres

Applied Mathematics and Mechanics - Mechanical models of residually stressed fibre-reinforced solids, which do not resist bending, have been developed in the literature. However, in some residually...     

Valence Quark Ratio in the Proton

Beginning with precise data on the ratio of structure functions in deep inelastic scattering（DIS） from ³ He and ³ H, collected on the domain 0.19 ≤ xB≤ 0.83, where xBis the Bjorken scaling variable, we employ a robust method for extrapolating such data to arrive at a model-independent result for the xB= 1 value of the ratio of neutron and proton structure functions. Combining this with information obtained in analyses of DIS from nuclei, corrected for target-structure depen...     

Dynamic and buckling analysis of polymer hybrid composite beam with variable thickness

This work deals with a study of the dynamic and buckling analysis of polymer hybrid composite(PHC) beam. The beam has variable thickness and is reinforced by carbon nanotubes(CNTs) and nanoclay(NC) simultaneously. The governing equations are derived based on the first shear deformation theory(FSDT). A three-phase HalpinTsai approach is used to predict the mechanical properties of the PHC. We focus our attention on the effect of the simultaneous addition of NC and CNT on the vibration and buckling analysis of the PHC beam with variable thickness. Also a comparison study is done on the sensation of three impressive parameters including CNT, NC weight fractions, and the shape factor of fillers on the mechanical properties of PHC beams,as well as fundamental frequencies of free vibrations and critical buckling load. The results show that the increase of shape factor value, NC, and CNT weight fractions leads to considerable reinforcement in mechanical properties as well as increase of the dimensionless fundamental frequency and buckling load. The variation of CNT weight fraction on elastic modulus is more sensitive rather than shear modulus but the effect of NC weight fraction on elastic and shear moduli is fairly the same. The shape factor values more than the medium level do not affect the mechanical properties.     

基于颗粒结构的砾岩粒度分级探讨――以准噶尔盆地西北缘为例

国内外地质学研究中,"Udden-Wentworth"的碎屑沉积粒度方案在砂岩分级中取得较好的应用.然而,对于粗碎屑砾岩因粒径跨度较大和缺乏地质成因的结构成因特征,在应用中受到限制.为此,本文从碎屑颗粒支撑结构出发,结合颗粒空间排列方式(最紧密和最松散两种极端排列方式),建立骨架颗粒与孔隙间填充颗粒的立体模型,计算出不同排列方式下填充颗粒的最大粒径,得到砾岩不同支撑类型的粒径临界值:5 mm、47 mm、87 mm及188 mm.由此,在"Udden-Wentworth"碎屑沉积物粒度方案的基础上,进一步对中砾岩和粗砾岩进行划分.将本方案应用于具体实例中,取得了良好的效果.     

The spin-isospin decomposition of the nuclear symmetry energy from low to high density

The energy per particle BA in nuclear matter is calculated up to high baryon density in the whole isospin asymmetry range from symmetric matter to pure neutron matter.The results,obtained in the framework of the Brueckner-Hartree-Fock approximation with two-and three-body forces,confirm the well-known parabolic dependence on the asymmetry parameterβ=(N?Z)/A(β^2 law)that is valid in a wide density range.To investigate the extent to which this behavior can be traced back to the properties of the underlying interaction,aside from the mean field approximation,the spin-isospin decomposition of BA is performed.Theoretical indications suggest that theβ^2 law could be violated at higher densities as a consequence of the three-body forces.This raises the problem that the symmetry energy,calculated according to theβ^2 law as a difference between BA in pure neutron matter and symmetric nuclear matter,cannot be applied to neutron stars.One should return to the proper definition of the nuclear symmetry energy as a response of the nuclear system to small isospin imbalance from the Z=N nuclei and pure neutron matter.     

Inversion of electrical mobility measurements using bipolar or unipolar chargers for the arbitrary distribution of channels

The inversion of the particle size distribution from electrical mobility measurements is analyzed.Three different methods are adapted for a dot-matrix approach to the problem,especially for non-square or singular matrices,and applied to electrical mobility measurements from fixed or scanning voltages.Multiply charged particles,diffusion losses,arbitrary voltage steps and noise were considered,which results in non-adjoining and overlapping transfer functions.The individual contribution of the transfer functions in each size interval was geometrically estimated,which requires only its characteristic mobilities.The methodology is applied to mobility measurements from particles charged with unipolar and bipolar chargers.However,the method can be extrapolated to any charging method with a defined charge distribution,and retrieval of the singly charged particle distribution and mean charge from a tandem differential mobility analysis configuration was successfully demonstrated.     

Highly transparent ceramics for the spectral range from 1.0 to 60.0μm based on solid solutions of the system AgBr-AgI-TlI-TlBr

The article is devoted to the technology for obtaining optical ceramics of Ag Br-Tl I and Ag Br-Tl Br_0.46I_0.54 systems and manufacturing samples with different compositions.The new heterophase crystal ceramics are transparent without absorption windows in the spectral range from 1.0 to 60.0μm.In the ceramics’transparency spectra based on the Ag Br-Tl I and Ag Br-Tl Br_0.46I_0.54 systems fusibility diagrams,with an increase in the thallium halides mass fraction,as well as the replacement of the bromine ion with iodine,the maximum transparency shifts to a long infrared region.     

Ag_(60)纳米颗粒[{Cl@Ag_(12)}@Ag_(48)(dppm)_(12)]的结构(其中dppm=双(二苯基膦基)甲烷)（英文）

本文合成一种新的双膦连接Ag_(60)纳米团簇[{Cl@Ag_(12)}@Ag_(48)(dppm)_(12)],并通过X射线晶体学进行表征.二十面体的银处于核心位置,里面是中心氯化物组成,外面有48个银原子/离子的包裹,顶端是12个双(二苯基膦基)甲烷(dppm)配体.同时利用密度泛函理论对阳离子[{Cl@Ag_(12)}@Ag_(48)(dppm)_(12)]~+进行计算,以确定该结构是否对应于核心数n=58的超原子.DFT计算的优化结构与X射线一致,但是HOMO-LUMO的能差并不能保证共超级稳定性.