One-pot multi-component synthesis of N,N′-alkylidene bisamides and imidazoles using heteropoly-11-tungsto-1-vanadophosphoric acid supported on natural clay as catalyst: A green approach

One-pot multi-component synthesis of N,N′-alkylidene bisamides, 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles in the presence of catalytic material heteropoly-11-tungsto-1-vanadophosphoric acid (HPV) supported on activated natural clay for about 20% (HPVAC-20) under solvent-free reaction condition have been achieved. Green heterogeneous reaction condition, simple workup procedure, short reaction time, high yield of products, and reusability of the catalyst are the advantages of this protocol.     

Comparative study of natural rubber/clay nanocomposites prepared from fresh or concentrated latex

Rubbers are usually compounded with different chemicals and fillers in order to modify their properties to suit the end applications. Natural rubber (NR) contains different natural occurring materials and this brings about subtle complexities in controlling compound and vulcanizate properties. Thus, the aim of this paper is to illustrate that the properties of compounds and vulcanizates of NR/clay prepared from fresh field latex and from concentrated latex are different. Different amounts of pristine clay were added to the two latices and their viscosity determined. The latex mixtures were next coagulated to form solid filled rubbers and their properties examined. Vulcanizates of these solid rubbers were then prepared and their properties, also, were determined. The cause of an observed variation is attributed to soluble proteins in the fresh field latex. Structural models to explain this are proposed.     

大埋深粘土三轴高压卸载变形与强度特征

以取自山东巨野矿区埋深近 4 30～ 6 0 0m的深部粘土样为例 ,分析测试了土的常规物理力学性质参数。考虑该埋深土的天然应力水平及其在煤矿建井开挖中的卸载应力变化 ,在三轴伺服仪上 ,进行三向等压分别达 11MPa、12MPa、14MPa下的卸除围压、保持轴压的三轴高压卸载试验 ,分析了深部粘土三轴高压卸载变形和强度特点 ,得到了相关力学参数。成果丰富了土的高压卸载力学性研究 ,并为巨野矿区煤矿立井建设提供了工程地质基础参数     

红粘土的微结构及其概化模型

本文论述红粘土的物质组成和微结构特征,在此基础上提出了红粘土微结构的概化模型,并根据这种模型对红粘土的工程特性进行了探讨。     

沿海软粘土取土质量的对比分析

本文在简要介绍固定活塞式薄壁取土器取土技术基础上，详尽分析了在连云港、赤湾港和广深路所进行的软粘土取土技术对比试验结果。试验结果表明，土样扰动对于室内所测定的力学性指标影响极大，但对物理性指标影响不大。研究结果还有力地证明，只要操作正确，采用薄壁取土器能取得高质量土样，而采用敞口式厚壁取土器取出的土样扰动较大。     

冲击荷载下土中浅埋箱形结构反应的模型试验研究

本文叙述了土中浅埋箱形结构模型动力试验结果。试验的目的是检验我们在文献[8、9]中,所提出的地表冲击波荷载作用下,土中箱形结构动力反应分析的两步法。试验有两种情况:一是利用室内模爆器进行的小模型(模型尺寸与实际结构之比约为1:40)试验;另一种是利用室外试验坑中进行的模拟平面波加载下的中等模型(尺寸缩比约为1:10)试验。试验的箱形结构有单孔与双孔两种。根据埋深与超压的不同,共进行了20炮次试验,试验对自由场中应力、结构周边压力、结构应变、结构运动等参数进行了测量。试验结果表明,所提出的两步分析法中关于土中结构内力分析的准静态法是可行的。     

Porous nanocomposite hydrogel of vinyled montmorillonite-crosslinked maltodextrin-co-dimethylacrylamide as a highly stable polymer carrier for controlled release systems

Nanocomposite hydrogel consisting of dispersed montmorillonite-crosslinked maltodextrin-co-dimethylacrylamide (malt-dex-co-DMAAm) as a highly stable device was developed. Carbon-carbon π-bonds issued from glycidyl methacrylate (GMA) were incorporated onto both the MMT (MMT-π) and the malt-dex (malt-dex-π) structures. The nanocomposite copolymer hydrogel was processed via radical crosslinking reaction of malt-dex-π with MMT-π in the presence of DMAAm. The radical reaction of the carbon-carbon π-bonds at the MMT-π was verified by treating the MMT-π with sodium persulfate. There was an excellent dispersion of the MMT-π at the interior of the matrix even after the nanocomposite hydrogel being swollen, demonstrating that the developed methodology can imprint stability of mineral nanoparticles into a porous polymer network preventing diffusion of water-bonded silicate platelets toward the outside matrix. The water absorption profile became more dependent on the polymer relaxation for mineral-loader nanocomposite hydrogels. Higher water absorption had an impact on reduction of elasticity modulus due to softer polymer network in swollen state.     

Carboxylate clays: A model study for polypropylene/clay nanocomposites

Sodium-montmorillonite was intercalated by carboxylate salts to prepare carboxylate clays. The intercalation of sodium acetate doubles the clay basal spacing and no degradation of the carboxylate clay is noticed in the extrusion temperature range. These carboxylate clays were used to synthesize polypropylene-graft-maleic anhydride (PP-g-MA)/clay nanocomposites. Nanocomposites were also produced by a one-pot process using in situ prepared carboxylate clay. The carboxylate salts within the clay layers partially neutralize the maleic anhydride groups of the PP-g-MA matrix, in situ during the melt compounding. The ionic groups of the partially neutralized polymer offer favourable interactions with the clay, hence reinforcing the interfacial bond between the polymer and the clay and improving the composite properties. The use of carboxylate clay clearly improves the clay dispersion into the PP-g-MA matrix and improves the nanocomposite’s thermal and rheological properties.     

Direct Electrochemistry of Myoglobin in DDAB-Clay Composite Films

Direct electrochemistry of redox proteins can provide a good model for the studies of redox process in biological system Electron transfer between redox metalloproteins and underlying electrodes was greatly enhanced in lamillar liquid crystal surfactant films compared to that on bare electrodes with the puoteins in solution1,because these filmsprovide a favorable biomebrane-like micuoencironment for the puwtins2 Orderedsurfactant-clay composite films in which anionic clay platelet layers sandw…     

Fluctuations of the second order observables for dissipative processes in 19F+27Al system

The excitation function (EF) data for dissipative processes in ¹⁹F + ²⁷Al system in the incident energy interval from 113.5 to 130 MeV are used to obtain the dependence of the charge variance and of the interaction time as a function of the incident energy. Fluctuations are observed in the EFs of both these secondary observables. Their correlation is supported by a mechanism based on stochastic exchange of nucleons.