火灾烟颗粒的分形结构形状模拟与光散射计算

针对火灾烟颗粒的形状特点，提出并建立火灾烟颗粒分形结构凝团的形状模型，并对烟颗粒扫描电镜(SEM)图像进行分析，获取分形结构模型中的单个凝团中基本颗粒个数、凝团分形维数、基本颗粒半径等参数.利用该模型对火灾烟颗粒的形状进行模拟的结果表明，该模型能够较好反映出烟颗粒的形貌特征.利用形状模型对火灾烟颗粒散射进行初步计算表明，在其他参数相同的情况下，相对于同体积的球形颗粒，分形凝团具有前向散射较弱，后向散射较强的特征.     

Electrolytic coloration of O2-doped NaCl crystals

O₂²⁻-doped NaCl crystals are colored electrolytically by using a pointed cathode and a flat anode at various temperatures and voltages, which mainly benefit from appropriate coloration temperatures and voltages as well as anode structure of used electrolysis apparatus. Characteristic OH⁻, U, V₂^m, U_A, V₂, V₃, O²⁻-V_a⁺ complex, F, R₁, R₂ and M absorption bands are observed in absorption spectra of the colored crystals. Production and conversion of color centers in electrolytic coloration is explained. Current-time curves for electrolytic colorations and their relationships with electrolytic colorations were given.     

Regularity for weakly (K 1, K 2(x))-quasiregular mappings of several n-dimensional variables

The definition for weakly (K ₁,K ₂(x))-quasiregular mappings of several n-dimensional variables is given. A regularity property is obtained by using the stability result of Hodge decomposition, some analytical tools of Sobolev spaces, and differential geometry, which can be regarded as a generalization of the results due to T. Iwaniec and Hongya Gao.     

A facile pathway for the fast synthesis of colloidal crystal‐loaded hydrogels via frontal polymerization

In this work, a dually sensitive colloidal crystal (CC)‐loaded hydrogel has been synthesized via frontal polymerization (FP) in a facile and rapid way. First, a polystyrene CC film was fabricated by vertical deposition on the inner wall of a test tube. Then, a mixture of acrylic acid (AAc), 2‐hydroxyethyl methacrylate (HEMA), and glycerol along with the initiator and crosslinker was added to this test tube to carry out FP, resulting in the formation of CC‐loaded hydrogel. The influence of the mass ratios of HEMA/AAc on front velocity and temperatures were studied. The swelling behavior, the morphology, and the stimuli‐responsive behavior of the CC‐loaded hydrogels prepared via FP were thoroughly investigated on the basis of swelling measurement, scanning electron microscopy, and reflection spectra. Results show that the as‐prepared CC‐loaded hydrogels exhibit excellent dual sensitivity to both methanol concentrations and pH values with very short response time, which can be observed visually without the aid of instruments. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Organic light‐emitting device dark spot growth behavior analysis by diffusion reaction theory

Dark spot growth rate tracing experiments performed on an organic light‐emitting device show that moisture entering into the device is relatively properly fitted by Fick's diffusion equation in the substrate/indium tin oxide (ITO)/hole transport layer (HTL)/silver (Ag) structure. It is believed that the moisture is dissolved into the polymer layer, which results in a decrease in the diffusion coefficient in the device with the substrate/ITO/HTL/electroluminescent (EL) polymer/Ag structure. The diffusion and chemical reaction occurring in the cathode layer further decreases the diffusion coefficient in the device with the substrate/ITO/HTL/EL polymer/calcium/Ag structure. Useful parameters, such as diffusion and solubility constants, describing possible mechanisms happening during dark spot growth on organic light‐emitting diode devices are extracted. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1697–1703, 2001     

Surface-Enhanced Raman Scattering (SERS) of Nitrothiophenol Isomers Chemisorbed on TiO2

Surface-enhanced Raman scattering (SERS) spectroscopy and density functional theory (DFT) calculations were used to investigate the nature of the charge-transfer (CT) process between nitrothiophenol (NTP) isomers and the n-type semiconductor, TiO₂. The Raman signals of p-NTP and m-NTP that were chemisorbed onto TiO₂ were significantly enhanced with respect to their corresponding neat compounds. In particular, an enhancement factor (EF) of 10²–10³ was observed for both p-NTP and m-NTP, with m-NTP displaying a larger EF compared to p-NTP. The Raman signal of o-NTP on TiO₂ was not detectable, owing to interference from fluorescence emissions. A molecule-to-TiO₂ charge-transfer mechanism was responsible for the enhanced Raman signals observed in p-NTP and m-NTP. This transfer was due to a strong coupling between the adsorbate and the metal oxide, which led to an optically driven CT transition from the HOMO of NTP into the conduction band of TiO₂. Based on the mesomeric effect, the NO₂ group para to the thiol had a stronger electron-withdrawing ability than the NO₂ group at the meta position. A less-efficient CT transition from p-NTP to TiO₂ in the surface complex resulted in a weaker Raman-signal enhancement for p-NTP compared to m-NTP. The DFT calculation determined that the HOMO and the LUMO of NTP bound to TiO₂ were located entirely on the adsorbate and the semiconductor, respectively, thereby supporting the experimental findings that a molecule-to-TiO₂ mechanism was the driving force behind the observed SERS effect.     

Smoke suppression of graphene platelets fabricated by Friedel–Crafts reaction in brominated flame-retarded PS

Journal of Thermal Analysis and Calorimetry - Graphene nanoplatelets (GNPs) were introduced into polystyrene (PS)/brominated polystyrene (BPS) blends to suppress the large amounts of smoke...     

A note on the lower semicontinuity of efficient solutions for parametric vector equilibrium problems

By using a new assumption, the lower semicontinuity of the efficient solution mappings for parametric vector equilibrium problems without a monotonicity assumption is established. Our result is different from recent ones in the literature. Some examples are given to illustrate the case.     

Large enhancements in gelation behavior of wheat gliadins by incorporation of low concentrations of methylcellulose

Influence of non-gelling methylcellulose(MC)on gelation behavior of wheat gliadins in 13 wt%alkaline propanol/water(50:50, v/v)solution was investigated using dynamic rheological time sweep test.Increasing MC concentration(C_(MC))up to C_(MC)=1wt% caused a significant reduction in gelation time(t_(gel))of the solution and an increase in loss tangent(tanδ)value of the resultant gel at T<30℃.