Coxeter–Chein Loops

In 1974, Orin Chein discovered a new family of Moufang loops which are now called Chein loops. Such a loop can be created from any group W together with ?₂ by a variation on a semidirect product. We first settle an open problem, originally proposed by Petr Vojtěchovský in 2003, by finding a minimal presentation for the Chein loop with respect to a presentation for W. We then study these loops in the case where W is a Coxeter group and show that it has what we call a Chein-Coxeter system, a small set of generators of order 2, together with a set of relations closely related to the Coxeter relations and Chein relations. In particular, even if the Moufang loop is infinite, it is finitely presented. Viewing these presentations as amalgams of loops, we then apply methods due to Blok and Hoffman to describe a family of twisted Coxeter–Chein loops.     

Thermodynamic and spectroscopic study of the interaction of Cu(II), Ni(II), Zn(II) and Ca(II) ions with 2-amino-N-(2-oxo-2-(2-(pyridin-2-yl)ethyl amino)ethyl)acetamide,a pseudo-mimic of human serum albumin

The protonation equilibria of 2-amino-N-(2-oxo-2-(2-(pyridin-2-yl)ethyl amino)ethyl)acetamide ([H₂(556)–N]) and the complexation of this ligand with Cu(II) Ca(II), Zn(II) and Ni(II) have been studied by glass electrode potentiometry and UV–visible spectrophotometry. From pH ∼2.00–11.00, five models for Cu(II) with the following complexes; MLH, ML, MLH₋₁, MLH₋₂ and MLH₋₃ were generated and observed to describe the experimental data equally well as far as the statistical criteria were concerned. The MLH₋₂ complex predominates at physiological pH in all five models, while the MLH₋₁ complex species exists only at low concentration in two models. The coordination in the MLH₋₂ complex suggested the involvement of one amino, two deprotonated peptides and one pyridyl nitrogen atoms. Molecular mechanics (MM) calculations confirmed the MLH₋₂ complex as the most stable species. Speciation calculations, using a blood plasma model, predicted that the Cu(II)–[H₂(556)–N] complex is able to mobilize Cu(II). Octanol/water partition of CuLH₋₂ showed that 30% of the complex went into the octanol phase, hence promoting percutaneous absorption of copper. The complex is a poor mimic of native copper–zinc superoxide dismutase.     

Investigations of pipe-diffusion-based dislocation climb by discrete dislocation dynamics

A new numerical dislocation climb model based on incorporating the pipe diffusion theory (PDT) of vacancies with 3D discrete dislocation dynamics (DDD) is developed. In this model we hold that the climb rate of dislocations is determined by the gradient of the vacancy concentration on the segment, but not by the mechanical climb force as traditionally believed. The nodal forces on discrete dislocation segments in DDD simulation are transferred to PDT to calculate the vacancy concentration gradient. This transfer establishes a bridge connecting the DDD and PDT. The model is highly efficient and accurate. As verifications, two typical climb-involved examples are predicted, e.g. the activation of a Bardeen-Herring source as well as the shrinkage and annihilation of prismatic loops. Finally, the model is applied to study the breakup process of an infinite edge dislocation dipole into prismatic loops. This coupling methodology provides us a useful tool to intensively study the evolution of dislocation microstructures at high temperatures.     

Cosmic string in the BTZ black hole background with time-dependent tension

In this Letter, we study the equation of circular loops with time-dependent tension in the BTZ black hole background. We obtain various cases where cosmic string loops finally collapse to form black holes. Also, we study effect of the BTZ black hole mass and angular momentum on the evolution of cosmic string loops. We find the critical values of initial radii as a limit for the cosmic string loops collapsing to form black holes.     

The influence of external magnetic field and femtosecond laser pulses on the anomalous Kerr loops in GdFeCo amorphous film

The anomalous loops obtained by applying the traditional Kerr loop technique, in which the sample was pumped by continuous pulses using the method of successive increment scanning external magnetic field, contained memory and accumulation effects originating, respectively, from external field history and multiple pulse excitations. To eliminate the memory effect and study the influence of external magnetic field on the anomalous loops, an initializing field scanning approach was used to replace the method of successive increment scanning external field. And to confirm the existence of accumulation effect and study the influence of pump pulses on the anomalous loops, a controllable pump-pulse-number magneto-optical Kerr technique was used to replace continuous pulses pump Kerr technique. In both ways, measured with different pump fluence and different pump pulses, the results showed clearly the dependence of the hot coercivity and the degree of magnetization reversal on the external field, pump pulse numbers and pump fluence.     

ON INVERSES AND ALGEBRAIC LOOPS OF CO-H-SPACES

In this paper we study the properties of homotopy inverses of comultiplications and Mgebraic loops of co-H-spaces based on a wedge of spheres. We also investigate a method to construct new comultiplications out of old ones by using a group action. We are primarily interested in the algebraic loops which have inversive, power-associative and Moufang properties for some comultiplications.     

Three-dimensional surface current loops in broadband responsive negative refractive metamaterial with isotropy

We propose a bulk negative refractive index (NRI) metamaterial composed of periodic array of tightly coupled metallic cross-pairs printed on the six sides of a cube for applications of superlenses. The structural characteristics of the three-dimensional (3D) metamaterial consist in the high symmetry and the superposition of metallic cross-pairs, which can increase the magnetic inductive coupling between adjacent cross-pairs and realize a broadband and isotropic NRI. The proposed 3D structure is simulated using the CST Microwave Studio 2006 to verify the design validity. The simulation results show that the proposed structure can not only realize simultaneously an electric and magnetic response to an incident electromagnetic (EM) wave, but also exhibit a broadband NRI whose relative bandwidth can reach up to 56.7%. In addition, the NRI band is insensitive to the polarization and the incident angle of the incident EM wave. Therefore, the proposed metamaterial is a good candidate material as three-dimensional broadband isotropic NRI metamaterial.     

基于长电偶极子和大磁圆环的新型电磁矢量传感器双基地多输入多输出雷达角度和极化参数联合估计

针对常规双基地电磁矢量传感器多输入多输出(multiple-input multiple-output,MIMO)雷达中短电偶极子(L/λ<0.1)和小磁环((2πR/λ)<0.1)辐射效率不足问题,本文根据实际应用中电磁矢量传感器的有效长度来设计新型的发射电磁矢量传感器阵列和接收电磁矢量传感器阵列.首先,通过平行因子...