Enhancement of pairing correlation by t' in the two-dimensional extended t-J model

We investigate the effects of the next-nearest-neighbor (t') and the third-nearest-neighbor (t") hopping terms on superconductivity correlation in the 2D hole-doped extended t-J model based on the variational Monte Carlo, mean-field calculation and exact diagonalization method. Despite the diversity of the methods employed, the results all point to a consistent conclusion: While the d-wave superconductivity correlation is slightly suppressed by t' and t" in underdoped regions, it is greatly enhanced in the optimal and overdoped regions. The optimal Tc is a result of the balance of these two opposite trends.     

智能建筑通信平台集约系统研究——制冷设备信号的底层通信

文中为智能建筑设计了一个通信网络系统,以实现建筑物内的低温信号采集处理和信息交换。在已有硬件设施基础上,利用基于FPGA的SOC设计技术,通过需求分析、算法设计,再到硬件开发、系统集成,实现对低温信号的处理完善,使之从系统的底层开始,为动平衡过程的所有信息交互提供服务。该系统可以满足BACNet标准和LONMARK标准,为智能建筑自控提供一套有效的信息处理模式。     

A multiplier rule on a metric space

A multiplier rule is proved for constrained minimization problems defined on a metric spaces. The proof requires a generalization of the values of a derivative in the classical case that the metric space is a normed space.     

Generation of hyperchaos from the Chen–Lee system via sinusoidal perturbation

A system with more than one positive Lyapunov exponent can be classified as a hyperchaotic system. In this study, a sinusoidal perturbation was designed for generating hyperchaos from the Chen–Lee chaotic system. The hyperchaos was identified by the existence of two positive Lyapunov exponents and bifurcation diagrams. The system is hyperchaotic in several different regions of the parameters c, ε, and ω. It was found that this method not only can enhance or suppress chaotic behavior, but also induces chaos in non-chaotic parameter ranges. In addition, two interesting dynamical behaviors, Hopf bifurcation and intermittency, were also found in this study.     

Thermo-optical study of UV cured polyether urethane diacrylate films with dispersed octadecanol

Thermally reversible light scattering (TRLS) films are prepared from ultraviolet (UV) curing of polyether urethane diacrylate (PEUDA) with dispersed low molecular weight 1-octadecanol (OD). Depending on the temperature, the OD domains are crystalline or amorphous and this produce opaque or transparent films in a reversible way. Stable optically transparent and light scattering states are obtained after 100 successive heating–cooling cycles. Moreover, morphologies of the OD domains could be varied significantly with the cure temperature and this led to notable discrepancy in optical properties. By using an UV-mask and curing in two steps at different temperatures, complex patterns could be recorded in the film that were encoded at high temperatures (60 °C) and revealed at low temperatures (i.e., at room temperature), which makes the film a candidate for thermo-optical recording medium.     

{[Eu(ox)(H2O)4]·[CuBr(2‐pzc)2]·4H2O}: Hydrogen Bonding Directed Assembly to Supramolecular Network

A new 3d–4f heterometallic coordination framework, {[Eu(ox)(H₂O)₄] · [CuBr(2‐pzc)₂] · 4H₂O} ( 1 ) [ox = oxalate; 2‐pzc = pyrazine‐2‐carboxylate] was synthesized and characterized by elemental analysis, IR spectroscopy and thermal analysis, as well as single‐crystal X‐ray diffraction. Complex 1 represents one 3D supramolecular heterometallic coordination framework that is assembled from rare lanthanide‐ox anionic chains and CuBr(2‐pzc)₂ cationic units through hydrogen bonds.     

Electrodeposition behavior of Mg with Zn from acidic sulfate solutions

Electrodeposition of Mg with Zn in acidic sulfate solutions with polyethylene glycol and octadecyl dimethyl benzyl ammonium chloride as additives was investigated by scanning electron microscopy, X-ray diffraction, and potentiodynamic polarization techniques. The results show that these two compounds act in a synergetic way to suppress Zn deposition markedly and facilitate Mg reduction. Zn–0.46%Mg coatings are produced under high cathodic current densities, which have lower corrosion potentials than Zn coatings and hydrogen evolution in neutral chloride solutions. Magnesium hydroxide may cause current oscillations at high cathodic polarizations in plating solutions without zinc salts due to its formation and peel-off. An “induced co-deposition” mechanism is proposed for Zn–Mg alloy electrodeposition.     

An ab initio simulation of the UV/Visible spectra of substituted chalcones

The electronic absorption spectra of 29 phenyl-ring substituted chalcones have been investigated with the time-dependent density functional theory (TD-DFT) and polarizable continuum TD-DFT (PCM-TD-DFT). It turns out that the hybrid PBE1PBE functional with the 6-31G basis set provide reliable λ_max when the solvent effects are included in the model. Comparisons with experimental values lead to a mean absolute error of 12 nm (0.136 eV). Moreover, the observed substituent effects are reproduced by calculation qualitatively. The λ_max of substituted chalcone in phenyl ring A is less sensitive to substitution than that in ring B. The linear correlation of Hammett’s substituent constants (σ_P) with LUMO energies is better with respect to HOMO energies. The calculation reveals that the maximum absorption band mainly results from the π→π* transition from HOMO to LUMO. The analysis of the electron density plots of frontier molecular orbitals show that most transitions should be of valence excitation nature.