THREE-SPACE-HARMONIC INTERACTION IN DOUBLY SINUSOIDAL PERIODIC MEDIA

Three-space-harmonic (3SH) interaction in doubly sinusoidal periodic (DSP) medium is investigated. Associated physical effects such as additional gap, defect state, and indirect gaps, are theoretically and numerically revealed. This simple DSP model can facilitate the understanding and utilizing of a series of effects in rather complicated periodic structures with additional defect or modulation.     

SH wave propagation in magnetic–electric periodically layered plates

In this paper, dispersive behavior and band structure of SH waves in magnetic–electric (ME) periodically layered plate are investigated by the transfer matrix method. Two kinds of unit cell form, one is piezoelectric (PE)/piezomagnetic (PM)/PE, and the other is PM/PE/PM, are considered in detailed. A peculiar case of the generalized single-celled plate is first presented and then the multi-celled periodical layered plates for discussion on the propagation behaviors and the band characteristics of SH waves, respectively. The effects on dispersive curves of four kinds of ME boundary conditions at the free surface of plates are discussed. Numerical examples for phase velocities or frequencies all show that the zero-order mode is non-dispersive both for single-celled and multi-celled periodically layered plates. The high modes of dispersive curves tend to the shear wave velocity of the slower sub-layer as frequencies increase both for these two structures. The frequency pass-band and frequency band gaps appear in multi-layered ME periodically layered plates. Electrical and magnetic boundary conditions, respectively, determine the dispersive curves for SH waves in the PE/PM/PE and PM/PE/PM periodically layered plates.     

The First Photochemical In Situ Production of Ti‐Based Nanoparticles: A SH2 Strategy Using Bis(cyclopentadienyl)titanium Dichloride (Cp2TiCl2)

Bis(cyclopentadienyl)titanium dichloride (Cp₂TiCl₂) is a high performance additive under UV light activation for both i) radical photopolymerization reactions (when added to a Type I photo­initiator such as 2,2‐dimethoxy‐2‐phenylacetophenone, the oxygen inhibition is reduced) and ii) a concomitant in situ photoinduced and oxygen mediated formation of Ti‐based nanoparticles (diameters ranging from 45 to 220 nm). The photochemical properties of Cp₂TiCl₂ are investigated by steady state photolysis and electron spin resonance, and its photoinitiation ability checked. The nanoparticles (NPs) are well characterized by transmission electron microscopy. The high reactivity of Cp₂TiCl₂ under air is ascribed to a bimolecular homolytic substitution (the S_H2 process is clearly demonstrated by density functional theory calculations and ESR experiments), which converts the peroxyls into new efficient initiating radicals. The photochemical in situ incorporation of Ti NPs has never previously been reported. The synthesis of metal nanoparticles by a S_H2 approach instead of the reduction of a metal salt appears to be a promising original method.

     

Electron impact total cross section calculations for CH3SH (methanethiol) from threshold to 5 keV

We report calculated total elastic cross sections Q_el, total ionisation cross sections, Q_ion, summed total excitation cross sections ∑Q_exc and total cross sections Q_T for CH₃SH upon electron impact for energies from ionisation threshold to 5 keV. We have employed Spherical Complex Optical Potential (SCOP) formalism to calculate total elastic cross section Q_el, and total inelastic cross section Q_inel and used Complex Scattering Potential – the ionisation contribution (CSP-ic) method to extract the ionisation cross sections, Q_ion, from the calculated Q_inel. The calculated total cross sections are examined as functions of incident electron energy and are compared with available data wherever possible and overall good agreement is observed. In this work Q_el, Q_ion, and ∑Q_exc are reported for the first time for CH₃SH in this energy range.     

Phonon-polariton and band structure of electro-magneto-acoustic SH wave propagation oblique to the periodic layered piezoelectric structures

Electro-magneto-acoustic SH waves propagating oblique to the periodic layered piezoelectric structures are studied under the coupling of the acoustic wave and the electromagnetic wave. Band structures of the so-called piezoelectric superlattice and phononic/photonic crystal are given both at acoustic frequencies and at optical frequencies. For the periodic layered piezoelectric structures, phonon-polaritons (the coupling modes of the phonons and photons) are found not only happening near the center of the Brillouin zone (in the long-wavelength limit) at acoustic frequencies, but also being able to appear in the whole Brillouin zone at optical frequencies. Appearing of these phonon-polaritons may provide a way to design a new type of acousto-optic devices.     

Bidual renormings of Banach spaces

Given a separable Banach space X with no isomorphic copies of ℓ₁ and a separable subspace Y of its bidual, we provide a sufficient condition on Y to ensure that X admits an equivalent norm such that the restriction to Y of the corresponding bidual norm is midpoint locally uniformly rotund. This result applies to the separable subspaces of the bidual of a Banach space with a shrinking unconditional Schauder basis and to the bidual of the James space.     

QM/QM docking method based on the variational finite localized molecular orbital approximation

We present a derivation of the semiempirical variational finite localized molecular orbital (VFL) approximation, which was introduced by Anikin et al. (J Chem Phys 2004, 121, 1266). On the basis of VFL approximation, we developed the novel semiempirical (quantum mechanical) QM/QM method in which a part of the system, including the ligand and protein active site, are treated self-consistently, while the protein bulk is considered as carrying a frozen electronic density matrix. The developed method is applied toward the QM docking study for the p56 LCK SH2 domain. The virtual search has predicted 10 most potent inhibitors by searching through the database of 200,000 empirically docked poses of 20,000 drug-like molecules. Energy score calculation of each complex roughly consisting of 1700 atoms took 14.54 s of single-CPU time at the NDDO AM1 level. The entire computation performed on a 32-CPU cluster would be accomplished in 1 day. Flexible ligand QM docking studies, performed on a subset of 10,000 poses, required 153.03 s of single-CPU time per complex. The entire calculation performed on the 32-CPU cluster would be finished in half-day.     

CH3SH与NO2的反应机理及动力学

在G3B3, CCSD(T)/6-311＋＋G(d,p)//B3LYP/6-311＋＋G(d,p)水平上详细研究了CH3SH与基态NO2的微观反应机理. 在B3LYP/6-311＋＋G(d,p)水平得到了反应势能面上所有反应物、过渡态和产物的优化构型, 通过振动频率分析和内禀反应坐标(IRC)跟踪验证了过渡态与反应物和产物的连接关系. 在CCSD(T)/6-311＋＋G(d,p)和G3B3水平计算了各物种的能量, 得到了反应势能面. 利用经典过渡态理论(TST)与变分过渡态理论(CVT)并结合小曲率隧道效应模型(SCT), 分别计算了在200～3000 K温度范围内的速率常数kTST, kCVT和kCVT/SCT. 研究结果表明, 该反应体系共存在5个反应通道, 其中N进攻巯基上H原子生成CH3S＋HNO2的通道活化势垒较低, 为主要反应通道. 动力学数据也表明, 该通道在200～3000 K计算温度范围内占绝对优势, 拟合得到的速率常数表达式为k1CVT/SCT＝1.93×10－16T0.21exp(－558.2/T) cm3&;#8226;molecule－1&;#8226;s－1.     

Polarization of SH waves at an In-plane sheared contact interface

An interesting phenomenon which can be used to detect the behaviour of a contact interface is investigated in this paper. SH waves are polarized at an in-plane sheared contact interface, so that the reflected and refracted waves consist of both anti-plane and in-plane waves.An induction function is defined, a process of iteration and a recurrence formula are developed to calculate this function. Some important results are obtained for the cases in which the two contact bodies are of identical material.     

Anti-Plane Shear Waves Scattering from a Partially Debonded Magneto-Electro-Elastic Circular Cylindrical Inhomogeneity

This article presents an analysis of the scattering of anti-plane shear waves from a single cylindrical inhomogeneity partially bonded to an unbounded magneto-electro-elastic matrix. The magneto-electric permeable boundary conditions are adopted. The crack opening displacement is represented by Chebyshev polynomials and a system of equations is derived and solved for the unknown coefficients. Some examples are calculated and the results are illustrated. The results show that the COD increases when the piezomagnetic coefficient of the inhomogeneity bonded to the piezoelectric matrix becomes larger, and that the COD decreases when the piezomagnetic coefficient of the matrix with the piezoelectric inhomogeneity increases.