Gerstenhaber brackets on Hochschild cohomology of general twisted tensor products

We present techniques for computing Gerstenhaber brackets on Hochschild cohomology of general twisted tensor product algebras. These techniques involve twisted tensor product resolutions and are based on recent results on Gerstenhaber brackets expressed on arbitrary bimodule resolutions.     

多阶梯梁系统的3:1内共振

研究了具有三次非线性项的多阶梯梁的振动,讨论了该系统3:1内共振情况,运用多重尺度法,即一种摄动技术,得到该问题的一般近似解,并得到两种模型的振幅和相位调制方程,这些方程组用来确定稳态解及其稳定性,假设外加的强迫频率接近于较低的频率,在研究的数值部分,讨论固有频率中的3:1情况,对两端固支和一端固支另一端简支,观测到的频率位于第一和第二固有频率之间;对两端简支,观测到的频率位于第二和第三固有频率之间,最后,利用数值算法求解3:1内共振,第一模型为两端固支和一端固支另一端简支梁的外激励模型;第二模型为两端简支梁的外激励模型,然后,当外激励第一模型时,研究第一、二模型的振幅,当外激励第二模型时,研究第二、三模型的振幅,对振动的内共振模型,画出强迫响应、阻尼响应和频率响应曲线,同时进行这些曲线的稳定性分析.     

Masses and Mixing of Neutral Leptons in a Grand Unified <Emphasis Type="Italic">E</Emphasis><Subscript>6</Subscript> Model with Intermediate Pati-Salam Symmetry

A brief review of the assignment of elementary fermions and bosons to irreducible multiplets in grand unified \(E_{6}\) models is followed by a discussion of different, hierarchical symmetry breaking chains from \(E_{6}\) down to \(SU(3)_{C} \times U(1)_{EM}\). We concentrate here on a model with an intermediate Pati-Salam symmetry for which \((B-L)\) is conserved. In particular, the mass/mixing matrix of electrically neutral fermions (i.e.neutrinos) that would be derived from Yukawa couplings is constructed. The pattern of neutrino masses and some bounds on mixing parameters are discussed.     

Spherically symmetric solutions of Einstein + non-polynomial gravities

We obtain the static spherically symmetric solutions of a class of gravitational models whose additions to the General Relativity (GR) action forbid Ricci-flat, in particular, Schwarzschild geometries. These theories are selected to maintain the (first) derivative order of the Einstein equations in Schwarzschild gauge. Generically, the solutions exhibit both horizons and a singularity at the origin, except for one model that forbids spherical symmetry altogether. Extensions to arbitrary dimension with a cosmological constant, Maxwell source and Gauss-Bonnet terms are also considered.     

Exact neutrino solutions in the presence of torsion

A class of exact solutions to the Einstein-Cartan-Weyl theory is presented. Certain subclasses of solutions which were previously known as “ghost” neutrinos are discussed in this context.     

Characterization of Solvent Effects on C=O Stretching Vibrations of Ketoprofen by Empirical Solvent Parameters

Journal of Applied Spectroscopy - The solvent effects on C=O stretching vibrational frequency, ν(C=O), of ketoprofen (KETO) were studied experimentally using attenuated total reflection...     

Structural Effects in the Addition–Fragmentation Reaction of Allylic Onium Salts

Allylic onium salts with different hetero‐atoms and various substituent groups at the allylic double bond have been shown to be very efficient initiators for cationic polymerization. When attacked by a radical, they become radical cations, which are highly unstable species, and undergo fragmentation into smaller radical cations called onium radical cations. The reaction mechanism involves radical formation, addition and fragmentation. In our previous work, radical initiators generated in the same way and under the same conditions are studied experimentally for their ability to affect the polymerization efficiency. Here, the factors affecting the polymerization efficiency are discussed theoretically using semi‐empirical quantum mechanical techniques. The type of radical species, substituent group at the allylic side, the heteroatom at the onium side and the onium group itself are analyzed separately. For this purpose, the geometries of different onium radical cations to be fragmented are optimized and the strength of the C–heteroatom bond to be broken and the size of the radical cations after fragmentation are considered.     

A novel replacement policy for a linear deteriorating system using stochastic process with dependent components

In this study, a mechanical system with linear deterioration and preventive maintenance is considered. The state of the system over time is represented by a semicontinuous stochastic process with dependent components. The system cycles through on and off periods during its lifetime. The state of the system deteriorates linearly as a function of the usage time during on periods. When the system is offline, preventive maintenance is conducted, which improves the system state by a random amount. The system's on and off times and random improvement amounts are assumed to have general distributions. For such a system, our objective is to determine the expected value and variance for the number of preventive maintenance activities needed during the system lifetime and to propose a novel replacement policy for the system based on delay‐time modeling. Finally, the effectiveness of the obtained asymptotic results and the proposed replacement policy are tested through simulation.     

Idempotent elements of the semigroup corresponding to an X-semilattice of unions of the class Σ16(X, 6)

It is known that if we know all XI-subsemilattices of a given X-semilattice of unions, then we can determine all idempotent elements of the semigroup, and the structure of idempotent elements is characterized. In this work, we find idempotent elements of the semigroup corresponding to X-semilattices of unions of the class ??₁₆(X, 6). Moreover, we give formulas for the number of idempotent elements, where X is finite.     

Enhancing effects of nanoparticles on polymer-OLED performances

We have previously reported that the silane coating of magnetic nanoparticles (MNPs) of maghemite phase could be used to protect iron oxide cores during plasma heat treatment, and even help to reduce their phase to magnetite with higher magnetization. In this work, an additional layer of an electrically conductive polypyrrole was added on top of the silane-coated MNPs, producing core?Cshell particles with sizes ranging from 150 to 500?nm. A microwave plasma heat treatment was used to convert the amorphous, already-conductive polypyrrole coatings into a more electrically conductive graphitic structure, while simultaneously reducing the iron oxide phase to magnetite. The treatment produced core?Cshell particles with better microwave absorption properties over the frequency of 1?C18?GHz, with a maximum reflection loss (absorption) of these MNPs at ?37?dB at 10.3?GHz for samples containing 70?wt% of plasma-treated core?Cshell nanoparticles embedded in wax. By comparison, the maximum absorption for the same amount of untreated nanoparticles was only ?18?dB at 7.5?GHz. The improved electromagnetic wave absorption properties were due to higher electrical conductivity of the more ordered, graphitic-like polypyrrole shell structures. This relatively simple protocol could thus be used to synthesize highly magnetic and conductive nanocomposites for electromagnetic interference shielding applications, particularly at the high frequency range.