Fabrication and characterization of micro-encapsulated sodium phosphate dodecahydrate with different crosslinked polymer shells

Microencapsulations of sodium phosphate dodecahydrate with different crosslinked polymer as shells were carried out by in situ polymerization and solvent evaporation method. Methyl methacrylate (MMA), urea were employed to crosslink with ethyl acrylate (EA) and formaldehyde, respectively. The influences of the type of crosslinking agent on the performance of as-prepared microencapsulated phase change materials (microPCMs) have been studied. The microPCMs were investigated using Fourier transformed infrared spectroscopy, scanning electron microscopy, and transmission electron microscope. Thermal properties and thermal stability of microPCMs were characterized by differential scanning calorimetry and thermalgravimetric analysis. Conclusion points out that thermal properties and thermal resistant temperatures of microPCMs vary from the type of crosslinkable functional moieties of the crosslinking agents. The temperature range of melting enlarged and the melting temperature increased according to the prepared microPCMs, which is suitable for thermal energy storage.     

Synthesis and photovoltaic properties of main chain polymeric metal complexes containing 1,10‐phenanthroline metal complexes conjugating alkyl fluorene or alkoxy benzene by C═C bridge for dye‐sensitized solar cells

Four main chain polymeric metal complexes (P1–P4) based on 1,10‐phenanthroline metal complexes via the Heck coupling have been synthesized and characterized by Fourier transform infrared spectroscopy, ¹H NMR, UV–Vis absorption, photoluminescence spectroscopy, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, elemental analysis, and cyclic voltammetry. To investigate their photovoltaic properties, the dye‐sensitized solar cells based on these polymers dyes are studied, under the illumination of AM 1.5G, 100 mW/cm². The study results show the four polymers exhibit good thermally stable and the solar cells based on them have good device performance, and the maximum power conversion efficiency is up to 0.735% for the solar cells based on P3 with a short‐circuit current (J_sc) of 1.68 mA/cm² and an open‐circuit voltage (V_oc) of 0.62 V. Copyright © 2012 John Wiley & Sons, Ltd.     

The EPR Spectra of Manganese(II) on Sulfonated Polystyrene Resins Cross-linked with Pure Divinylbenzene Isomers

The EPR spectra of manganese(II) ions on sulfonated polystyrene cross-linked with either pure meta or pure para divinylbenzene show distinctions indicative of ionic environments of different symmetry.     

SYNTHESES AND BIOLOGICAL ACTIVITIES OF 1,2,4-TRIAZOLO-[3,4-B][1,3,4]THIADIAZOLE DITHIOPHOSPHATES

In this article, we incorporated the organic phosphorus group on to a triazolothiadiazole ring to prepare the title compounds fused 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole heterocyclic compounds. From the results on biological activities, we found that most compounds showed weak activities, and thus the structures need to be further optimized for improved activity.     

Completions of certain modules over quantum groups 1

Completion is a procedure of constructing new representations for Lie algebras from given ones. This paper shows that a similar procedure exists for quantum groups.     

不同尺寸的NdFeB稀土永磁体热退磁行为研究

针对不同类型及不同尺寸的两类NdFeB永磁体分别研究了它们随温度变化的热退磁行为。采用样品的整体剩余磁通来表征热退磁过程中磁体性能的变化。结果表明,Pc较小的永磁体温度稳定性较差,随温度的升高,样品的剩余磁通迅速衰减;Pc<<0.1的普通型永磁体,温度为100℃时样品的剩余磁通损失超过60%。高矫顽力型永磁体比普通型磁体具有更优越的温度稳定性和高温性能。温度升高主要导致磁体矫顽力降低,140℃时普通型磁体的矫顽力降低约80%,而高矫顽力型磁体的矫顽力只降低了约20%。     

Chemorheology and Curing Kinetics of a New RTM Benzoxazine Resin

The chemorheology and curing kinetics of a new high performance resin transfer molding benzoxazine resin was investigated. A chemorheological model based on a modified Arrhenius equation that describes the resin viscosity as a function of temperature and time was proposed. The model, which agreed well with the experimental data, can provide theoretical support for the mold-filling stage in the resin transfer molding process. The average activation energies of the polymerization reaction were obtained by means of gelation times at different temperatures based on the Arrhenius equation and from dynamic differential scanning calorimetry (DSC) results based on the Kissinger and Ozawa methods; the values were 96.0,84.0 and 87.8 KJ/mol, respectively. A plot of activation energy vs. conversion in the curing process was obtained using the Flynn-Wall-Ozawa model. The reaction orders were estimated from isothermal DSC based on a modified Kamal kinetics model which can describe both the autocatalytic and diffusion-controlled curing mechanism.     

A Facile Preparation of Methoxymethyl Ethers of Primary and Secondary Alcohols with Dimethoxymethane Catalysed by Expansive Graphite

An easy preparation of methoxymethyl ethers of primary and secondary alcohols with dimethoxymethane has been carried out in excellent yield under catalysis of expansive graphite.     

A Convenient and Effective Synthesis of Tris-Bridged Tricationic Azolophanes

Two new macrobicyclic imidazolium and benzimidazolium phanes were synthesized by direct quaternization of the corresponding tripodal azacycles with tribromide under high dilution condition in excellent yields. The cyclophanes were identified by ¹H-NMR, ¹³C-NMR, FAB-MS, IR, elemental analysis and X-ray diffraction analysis.     

基于泰勒级数及温度因子的卡尔曼滤波模型在链子崖危岩体变形预测中的应用

考虑到链子崖危岩体的变形受温度的影响较为明显,为此,将链子崖危岩体的变形看作时间和温度的函数,利用泰勒级数建立链子崖危岩体的变形与时间和温度的函数关系,并将泰勒级数的余项及时间变化的二次方和温度变化的二次方的系数的变化量看作数学期望为0的动态噪声,建立卡尔曼滤波模型,并用于链子崖危岩体变形的预测预报.实例计算表明,模型的拟合效果和预测效果较好.