On the reliability of determination of energies of HOMO and LUMO levels in organic semiconductors from electrochemical measurements. A simple picture based on the electrostatic model

Relations between energies of ionized levels (HOMO and LUMO levels) obtained from photoelectron spectroscopy (UPS and IPES) of molecular solids, and oxidation (reduction) potentials of respective molecules dissolved in non-aqueous solvents are re-examined. Several classes of molecules are taken into account: polycyclic aromatic hydrocarbons, fullerenes, aromatic amines and anhydrides, sulfur- and selenium-containing molecules, coordination complexes, etc. It is demonstrated that the equations, commonly employed to evaluate the solid state energies of ionized levels from electrochemical measurements, should be modified. Based on literature data gathered for over 100 molecules, empirical correlations are determined allowing for estimation of the solid-state ionization energies and electron affinities from electrochemical experiments. The correlation coefficients depend on the selection of molecules involved and potential range but for the most common combination of these two parameters the following correlations are proposed: I_c = (1.15 ± 0.09) × (eπ_ox) + (4.79 ± 0.07) eV, and A_c = (1.18 ± 0.05) × (eπ_red) + (4.83 ± 0.10) eV. A model is put forward explaining the course of the correlations.     

An image pixel based variational model for histogram equalization

In this paper, we develop an image pixel based histogram equalization model for image contrast enhancement. The approach is to propose a variational model containing an energy functional to adjust the pixel values of an input image directly so that the resulting histogram can be redistributed to be uniform. This idea is different from existing histogram equalization algorithms where a histogram based on the input image is constructed, a mapping is determined to output a uniform histogram and then the pixel values of the input image are adjusted based on the mapping. In the variational model, a mean brightness term is incorporated to preserve the brightness of the input image, and a geometry constraint can also be added to keep the geometry structure of the input image. Theoretically, the existence of the minimizer of the proposed model, and the convergence of the proposed algorithm are given. Experimental results are reported to demonstrate that the performance of the proposed model are competitive with the other testing histogram equalization methods for several testing images.     

An evaluation method for measuring SPL and mode shape of tire cavity resonance by using multi-microphone system

This paper presents an evaluation method for measuring the sound pressure level and mode shapes of tire cavity resonance by using a multi-microphone system. Two commercial tires were evaluated to compare abilities of noise suppression by means of this method in the range of the first resonance from 200 to 260 Hz. One tire was a special tire that suppresses tire cavity resonance with polyurethane foam mounted on the tire’s inner liner. The other tire was a normal tire with no polyurethane foam. The mode shape change from vertical to horizontal direction in both tires. However, the sound pressure level of the special tire was lower than the normal tire at all frequencies.     

On The Cut-off Parameters in the Bosonization Technique

Jordan's boson representation and cut-off repolarization for the one-dimensional two-fermion model (TFT) is used to get the equivalence of the model with the two-dimensional Coulomb gas and sine-Gordon model. The scaling equations for the coupling constants are thereby obtained up to the third order.     

Liquid crystalline properties of 4‐hexyloxybenzylidene‐4′‐alkyloxyanilines

The liquid‐crystalline polymorphism of the homologous series of 4‐hexyloxybenzylidene‐4′‐alkyloxyanilines is investigated. Basing on the polarization microscopy (POM, TOA), the DSC calorimetry and miscibility studies the following mesophases were detected: nematic, smectic A, smectic C and smectic I. The phase diagrams of the compounds of these series with 4‐hexyloxybenylidene‐4′‐pentylaniline (as the standard of mesophases) show induction of the smectic F mesophases. Their dependence on the alkyl chain length and mole fraction is shown.     

Strain rate effects on compressive behavior of covalently bonded CNT networks

In this study, strain rate effects on the compressive mechanical properties of randomly structured carbon nanotube (CNT) networks were examined. For this purpose, three-dimensional atomistic models of CNT networks with covalently-bonded junctions were generated. After that, molecular dynamics (MD) simulations of compressive loading were performed at five different strain rates to investigate the basic deformation characteristic mechanisms of CNT networks and determine the effect of strain rate on stress–strain curves. The simulation results showed that the strain rate of compressive loading increases, so that a higher resistance of specimens to deformation is observed. Furthermore, the local deformation characteristics of CNT segments, which are mainly driven by bending and buckling modes, and their prevalence are strongly affected by the deformation rate. It was also observed that CNT networks have superior features to metal foams such as metal matrix syntactic foams (MMSFs) and porous sintered fiber metals (PSFMs) in terms of energy absorbing capabilities.     

Multi-scale noise estimation for image splicing forgery detection

Noise discrepancies in multiple scales are utilized as indicators for image splicing forgery detection in this paper. Specifically, the test image is initially segmented into superpixels of multiple scales. In each individual scale, noise level function, which reflects the relation between noise level and brightness of each segment, is computed. Those segments not constrained by the noise level function are regarded as suspicious regions. In the final step, pixels appears in suspicious regions of each scale, after necessary morphological processing, are marked as spliced region(s). The Optimal Parameter Combination Searching (OPCS) Algorithm is proposed to determine the optimal parameters during the process. Two datasets are created for training the optimal parameters and to evaluate the proposed scheme, respectively. The experimental results show that the proposed scheme is effective, especially for the multi-objects splicing. In addition, the proposed scheme is proven to be superior to the existing state-of-the-art method.     

液体空分流程形式浅析

通过对全液体空分装置不同流程组织形式进行分析和模拟计算、能耗与投资的比较,根据不同规格的产品要求,进行合适的流程形式选择,以可达到节能降耗的目的。     

Liquid-crystalline fork-like dendrons

ABSTRACT

Dendritic molecules having several rigid-rod moieties can be applied to induce liquid crystallinity for a variety of non-mesomorphic functional molecules such as metal complexes, nanoparticles, fullerenes and π-conjugated molecules when these dendritic molecules are covalently bonded to those non-mesomorphic molecules. These complex molecules are called supermolecular liquid crystals. Due to the cooperation of several mesogenic moieties, these dendritic molecules exhibit very stable liquid-crystalline (LC) phases. We have used fork-shaped LC dendrons having two or three rigid-rod moieties to induce liquid crystallinity for functional molecules such as interlocked molecules and π-conjugated molecules. In these fork-like molecules, the rigid-rod cores are attached to the 3,4,5-position of the phenyl moieties through flexible spacer, and these molecules are bonded to functional molecules through the 1-position. They basically form smectic LC phases, which induce the layered arrangement of functional moieties. Here we report on a new family of fork-like mesogens containing a hydrogen bonding moiety or an ionic group. They are designed to build supramolecular materials.