Timoshenko beam model for chiral materials

Natural and artificial chiral materials such as deoxyribonucleic acid （DNA）, chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton＇s principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

Dispersion Relation of δ Meson and Pion at Finite Nuclear Density in Chiral δ Model

The propagators of pion and sigma meson at a finite nuclear density and zero temperature are studied in chiral σ model. Their dispersion relations are calculated numerically in one-loop approximation. In order to avoid the so-called tachyon pole appearing in the one-loop propagators of pion and sigma meson, we regard the mass of sigma meson mσ as a free parameter and adjust it to fit the nuclear saturation properties. For mσ equal to 3075 MeV, the tachyonpole does not appear at the normal nuclear density. Thus the dispersion relation can be calculated in chiral σ model in one-loop level for the first time.

Study of Ratio of Proton Momentum Distributions with a Chiral Quark Model

The ratio between the anomalous magnetic moments of proton and neutron has recently been suggested to be connected to the ratio of proton momentum fractions carried by the valence quarks inside it. This moment fraction ratio is respectively evaluated by using constituent quark model and chiral quark model in order to check meson cloud effect. Our results show that the meson cloud effect is remarkable to the ratio of the proton momentum fractions, and therefore, this ratiois a sensitive test for the meson cloud effect as well as for the SU(6) symmetry breaking effect.

Equation of State of Nuclear Matter in Chiral σ-ω Model

The equation of state of nuclear matter is studied in the 1-loop approximation of chiral linear σ-ω model.By introducing the density-dependent coupling constants, the problem of tachyon pole in the chiral σ-ω model is resolved.The 1-loop contributions ofσ and π mesons to the nucleon's binding energy are included, while the empirical properties of nuclear matter such as saturation density, binding energy, and incompressibility are well reproduced.

Hypernucleus-^(16)O in the density-dependent Hartree approach based on the chiral-σ model

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｔｕｄｉｅｓｏｆｔｈｅｈｙｐｅｒｎｕｃｌｅｕｓｓｔｒｕｃｔｕｒｅａｒｅｖｅｒｙｂｅｎｅｆｉｃｉａｌｆｏｒｉｎｖｅｓｔｉｇａｔｉｎｇｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅｂａｒｙｏｎｂａｒｙｏｎｉｎｔｅｒａｃｔｉｏｎｉｎｎｕ...

An Improved and Efficient Preparation of the Chiral NAD(P)H Model (S_s)-1-Benzy1-3-(p-tolylsulfinyl)-1,4-dihydropyridine

An improved procedure for the preparation of China, BAD(P)H model. (S_s)- 1 -benzyl-3- (p-tolylsulfinyl)-1.4-dihydropyridine with satisfactary chemical yield and excellent enantiopurity is reported.

Chiral Current in the Lattice Model of Weyl Semimetal

We demonstrate the existence of the chirai magnetic effect in a simple lattice model of Weyl semimetal, which is a hallmark of chiral anomaly in the Weyl semimetal, by calculating the anomalous charge current directly. We identify that the uniform external magnetic field can induce a non-dissipative charge current along its direction in Weyl semimetal, even in the absence of an external electric field if the right and left handed Weyl points are separated in energy, and that the anomalous current is proportional to the strength of the magnetic field and the energy separation with a universal coetticient e2/h2, which coincide with the ones predicted on the basis of the field theory treatment. Our results give the possibility to detect these nontrivial electrodynamic phenomena in real materials of Weyl semimetal.

Comparison of the Linear Sigma Model and Chiral Perturbation Theory for Nucleon Properties

We compare the static nucleon properties in the Chiral Perturbation Theory (χPT) and the Linear Sigma Model (LSM). We consider a chiral model for the nucleon which is based on the linear sigma model with scalar-isoscalar and scalarisovector mesons coupled to quarks. We have solved the field equations in the mean field approximation for the hedgehog baryon state with different sets of model parameters. A good investigation of some static nucleon properties is obtained by the LSM.

Behavior of the Chiral Soliton Model at High Temperature and Chiral Phase Transition

The calculations of the soliton solutions in the chiral soliton model are fin-ished via a numerical method with the aim of analysing the influence of thermal effectson chiral solitons.An intuitive physical picture about chiral restoration phase transitionin a strong interacting system is also shown.

Surface second harmonic generation of chiral molecules using three-coupled-oscillator model

Based on the three-coupled-oscillator molecular model we proposed, the relation between the second-order susceptibilities of a chiral film and the molecular hyperpolarizabilities is given. The effect of microscopic parameters on the second-order susceptibilities is simulated numerically and the difference between the efficiencies of s-polarized secondharmonic fields induced by the left- and the right-handed circularly-polarized fundamental beams is discussed. The theoretical basis for studying second-order nonlinear optical properties of the chiral molecular media with a tripod-like structure is provided in this paper.

Geometrical Model Based Refinements in Nanotube Chiral Indices

There is demonstrated how it is possible to refine graphitic nanotubes’ chiral indices based on the appropriate geometrical model for their structure.

Chiral σ-ω Model Study of Hot Dense Nuclear Matter

The hot dense nuclear matter is studied in the chiral σ-ω model in theformalism of thermo-field dynamics.The binding energy,pressure and effective mass ofnucleon are calculated in the level of one-loop vaccum quantum fluctuation.The tem-perature effect is found very large at high temperature and the pressure can not reachsaturation as a function of nuclear density.

磁场背景下具有手征化学势的PNJL模型下的手征相变

采用具有两个味道的PNJL模型研究了均匀磁场背景下的手征相变,特别是磁场对手征相变的临界手征化学势的影响.结果表明,磁场对手征对称性自发破缺具有催化作用,即临界手征化学势随着磁场增大而增大.夸克的组分质量随磁场增大,但它随手征化学势的变化不一定是单调的,在接近临界手征化学势时,夸克的组分质量会单调减小,直至发生手征相变.同时也讨论了体积对临界手征化学势的影响,发现在简化处理方式下,系统尺度的减小会导致临界手征化学势的明显增大.

基于特征手性的数据无关模型评估方法

模型评估是评判卷积神经网络模型性能的重要手段,多用于卷积神经网络模型的设计、对比和应用过程。然而,现有的模型评估方法大多需要使用测试数据运行模型得到相关评估指标,当测试数据因隐私、版权与保密等原因无法获取时难以发挥作用。为了解决此问题,提出了一种数据无关的卷积神经网络模型评估方法,其利用特征手性的相关特性,通过计算卷积核之间的距离来确定模型的评估指标。所提方法利用不同卷积神经网络模型的性能表现与卷积核距离之间的负相关性,验证了在不使用测试数据的情况下,直接利用模型参数评估模型相对性能排名的可行性与有效性。对比实验表明,使用欧氏距离测度来评估AlexNet, VGGNets, ResNets, EfficientNets这4类包括17个卷积神经网络的模型精度时,该模型评估方法的盲评准确性高,能够较好地完成模型评估任务。

钙拮抗剂尼莫地平对映体在Chiralcel OJ柱上的拆分机理

采用高效液相色谱法(HPLC),在Chiralcel OJ手性柱上拆分尼莫地平。以正己烷-异丙醇为流动相,研究了异丙醇体积含量、流速及柱温对尼莫地平对映体拆分行为的影响。并结合溶质计量置换保留模型和热力学理论对尼莫地平的手性识别机理进行探讨。实验表明V(正己烷)∶V(异丙醇)=90∶10,流速0.6 mL/min,柱温25℃时,尼莫地平对映体可实现良好分离。在实验的异丙醇浓度范围内,前一个对映体lgI值和Z值均小于后一个对映体。热力学函数焓变和熵变之差为负值,分离对映体满足||ΔΔH0||>||ΔΔS0||,手性拆分过程为焓控过程。

Chiral phase transition of quark matter in the background of parallel electric and magnetic fields

We report on our results about spontaneous chiral symmetry breaking for quark matter in the background of static and homogeneous parallel electric field,E,and magnetic field,B.A Nambu–Jona–Lasinio model is used to compute the dependence of the chiral condensate at finite temperature,E and B.We study the effect of this background on inverse catalysis of chiral symmetry breaking for E and B of the same order of magnitude.We also consider the effect of equilibration of chiral density,n_5,produced by axial anomaly on the critical temperature.The equilibration of n_5 allows for the introduction of the chiral chemical potential,u_5,which is computed selfconsistently as a function of temperature and field strength.We find that even if the chiral medium is produced by the fields the thermodynamics,with particular reference to the inverse catalysis induced by the external fields,it is not very affected by n_5 at least if the average u_5,at equilibrium is not too large.

Local evolutions of nodal points in two-dimensional systems with chiral symmetry

Two-dimensional systems with chiral symmetry allow stable discrete band crossings(nodal points) in Brillouin zones.Here we study the local evolutions of these nodal points under chiral symmetry preserving perturbations.We find that these evolutions can be classified by different types of local k·p models around the nodal points.Several concrete examples are calculated to illustrate our results.

Molecular Dynamic Study for Chiral Discrimination of α-Phenylethylamine by Modified Cyclodextrin in Gas Chromatography

A molecular dynamic method in conjunction with a statistic test has been utilized to model chiral recognition of a-phenylethylamine on heptakis (2.6-di-O-butyl-3-O-butyryl)-β- cyclodextrin in gas chromatography. The modelling data correlated with the chromatographic elution order and indicated that the preferred site of α-phenylethylamine is the interior of cavity.

Adsorptive Interaction of Chiral Amino Acids on <i>β</i>-Cyclodextrin Bonded to Silica Particles

The adsorption of certain chiral amino acids from aqueous solution onto β-cyclodextrin silica particles (CDS) had been investigated with the aim of in-depth understanding of the host-guest interaction. The adsorption intensity was found to be strongly dependent on the aqueous phase pH and this dependence could be interpreted from a model for neutral species adsorption in all cases. Adsorption equilibrium data fitted well to the Freundlich isotherm. The adsorption efficiencies of L-amino acids were found to be higher compared to the corresponding D-isomers. Hydrogen bonding and hydrophocities of amino acids were responsible for the differences in adsorption, by influencing the strength of interactions between the amino acid and CDS. The adsorption rate curves for all the molecules appeared to be typical of the pseudo second-order kinetics. Infrared spectral analysis has been performed to characterize adsorptive interaction. The porous structure of CDS as revealed by scanning electron micrograph thus shown to be promising materials for enantioselective separation of amino acids. In addition, molecular modeling studies performed on such molecules were found to correlate very well to the experimental results obtained.

Radial Excitations in the Global Colour Soliton Model

With the Munczek-Nemirovsky model of the effective gluon propagator in the global colour model, we study the radially excited solitons in which one quark is excited and the other two are at the ground state. The obtained masses of the two radial excitations are comparable with the experimental data.