A new composite polypropylene material with improved physicochemical and consumer properties

A new composite material, polypropylene threads fi lled with nanosized copper powder, was prepared. The material exhibits decreased electrical resistivity.     

A new technique for preparing macroporous inorganic composite material

Macroporous CdS/SiO₂ was prepared with a new approach in which at first CdS nanoparticles were deposited on polymer microbeads without surfactant, then core-shell composite was self-assembled with sedimentation-aggregation, and at last macroporous material was obtained by the removal of the template. The results show that the morphology of core-shell composite could be tailored by the polymer template and the concentration of the reactant, and the shell thickness could be altered by the temperature and the aging time. This new idea was an effective method to prepare other macroporous composite with large-scale.     

A new route to MFI/MCM-41 micro-mesoporous composite

A new route to MFI/MCM-41 micro-mesoporous composite is reported. This composite was synthesized for the first time by the hydrothermal microwave two-template method, and the stage of crystallization was carried out for the first time at 190°C. The developed procedure makes it possible to significantly reduce the time of synthesis of the MFI/MCM-41 micro-mesoporous composite as compared with the known methods.     

A new approach to 4,6-disubstituted-3,4-dihydropyran-2-ones by Domino Michael addition-cyclization reaction under PTC conditions

Domino Michael addition-cyclization reactions of α,β-unsaturated carbonyl compounds with activated 1,3-dithiane-2-carbothioate esters under solid-liquid phase transfer catalysis conditions provide 4,6-disubstituted-3,4-dihydropyran-2-one-3,3-dithioacetals in good chemical yield. Desulfurization proceeds chemoselectively under mild conditions affording 3,4-dihydropyran-2-ones in high yields.     

A new evanescent wave ammonia sensor based on polyaniline composite

A single-mode TE(0)-TM(0) optical planar waveguide ammonia sensor based on polyaniline/polymethyl methacrylate (PANI/PMMA) composite is designed and developed. The sensing properties of the photonic sensor to ammonia at room temperature are studied. A significant change is observed in the guided light output power of the sensor after it is exposed to ammonia gas. The metrological parameters (sensitivity, response time and recovery time) of the sensor are strongly influenced by the interaction length (length of sensing region). Compared with the conventional optical ammonia sensor based on absorption spectroscopy, the integrated optical sensor is more sensitive to ammonia.     

新型高效相转移催化剂在二氯卡宾制备中的应用

本文合成了分子内具有缩乙二醇甲醚链段的季铵盐类,既能与阳离子络合,又能与阴离子部分络合。通过氯仿与环乙烯或苯甲醛的加成反应,证明它是一类高效相转移催化剂。     

A dielectric anomaly at the metal-nonmetal transition

The divergence in the real part of the dielectric constant which accompanies a metal-nonmetal transition is described. Particular attention is paid to metal-ammonia solutions.     

A new upper bound for a critical anomaly in the dielectric constant of SF6

The dielectric constant of SF₆ on the critical isochore was measured under conditions of high thermal stability and low gravitational disturbance. No direct evidence of a t^1-α-type anomaly was found, an upper bound for its amplitude is presented.     

A new type of nano-sized silicon/carbon composite electrode for reversible lithium insertion

A new type of nano-sized silicon/carbon composite was developed. It shows superior electrochemical cycling properties as negative electrode material for possible use in lithium-ion batteries with respect to high reversible and low irreversible capacity, and low fading.     

钯催化下烯基硒化物与氰化钾的相转移偶联反应——α,β-不饱和腈的立体选择合成

在钯及相转移催化剂存在下，烯基硒化物与氰化钾在苯中可顺利发生交叉偶联反应，提供了α，β－不饱和腈的立体选择合成法，产率达７５％～９５％。     

A structural polymeric composite material reinforced with basalt fiber

A process was developed for preparing a polymeric composite material by combining the synthesis of the oligomer with its reinforcement with basalt fiber. The advantage of this process relative to the traditional technology is more efficient interaction of the oligomer with the basalt fibers, positively affecting the composite formation and ensuring improved physicochemical and mechanical properties of the basalt-reinforced plastics.     

PTC/NTC Behavior of PVDF Composites Filled with GF and CF

Conductive polyvinylidene fluoride（PVDF）matrix composites filled with graphited fiber（GF）or carbon fiber（CF）were prepared by the melt-mixing method.The breakage and length distribution of the fibers in the polymer matrix were studied by scanning electron microscope（SEM）and optical microscope（OM）observations,respectively. The differences in the positive temperature coefficient（PTC）effects of the composites were mainly attributed to inter-fiber contact ability.The elimination of the negative temperature coefficient（NTC）effect for CF/PVDF composite was because of an increase in the viscosity of the polymer matrix.With the same filler content,CF could be more effective,to eliminate the NTC effect when compared with GF.Addition of 2%CF（mass fraction）in the PVDF composite with 7%GF（mass fraction）could effectively eliminate the NTC phenomenon of the composite.     

Synthesis and Spectral Characterization of 2-Mercaptobenzimidazole Derivatives Using a new Active Phase Transfer Reagent Under PTC Conditions

The phase transfer catalyzed synthesis of 2-Mercaptobenzimidazole derivatives using the new active phase transfer reagent namely, 2-benzilidine-N,N,N,N',N',N'-hexaethyl propane-1,3-dimonium dibromide (Dq-Br) have been described. The structures of all the fifteen compounds have been established by spectroscopic means.     

A new modified conducting carbon composite electrode as sensor for ascorbate and biosensor for glucose

A new carbon-based conducting composite has been developed as electrochemical sensor and biosensor for the amperometric detection of ascorbate and glucose. Electrocatalytic oxidation of ascorbate has been done successfully at unmodified cellulose acetate-graphite composite electrodes, the sensor being highly sensitive, selective and with a low detection limit at 0.0 V vs. SCE and was successfully applied for ascorbate determination in commercial fruit juice samples. An interference free glucose biosensor has also been developed, based on the immobilisation of glucose oxidase by cross-linking with glutaraldehyde on poly (neutral red) modified composite electrodes. The biosensor exhibits a higher sensitivity of 31.5 ± 1.7 µA cm^− 2 mM^− 1 than other carbon-composite-based glucose biosensors, a detection limit of 20.3 µM and a very short response time.     

PTCBaTiO3瓷的电子探针研究

利用电子探针对PTC BaTiO_3陶瓷的晶粒和晶界进行了分析研究。发现某些晶界存在着Sb、Cr、Ca和Al、Si的高度富集。这些特殊的不均匀性对陶瓷的性能有较大影响。     

PE/CB复合材料的辐照效应

研究了两种炭黑(CB)对PE的影响及PTC功能材料挤出后的特性，发现挤出后粒子和聚合物取向对材料电性能都有较大影响。经γ射线辐照后HDPE／CB功能复合材料稳定性大为提高，初步探讨了辐射对PTC功能材料稳定性的影响。结合辐射交联等方法提高材料的稳定性。用扫描电镜(SEM)观测了一系列PE／CB的形态、CB的分布、链段的分子运动，并结合Fisher的toy model对PE／CB机制做了较系统的解释。     

A new lead single flow battery in a composite perchloric acid system with high specific surface capacity for large-scale energy storage

In this paper, we propose a full lead single flow battery with ultra-high specific surface capacity, which is achieved by the combined effects of electrochemically deposited lead as a negative electrode, electrodeposited PbO₂ on Pt-plated titanium (Pt/Ti) plate as a positive electrode, and the composite perchloric acid with additives as an electrolyte. Experimental results indicate that this newly developed single flow battery provides a specific surface capacity of 125 mAh cm^?2, five times higher than that of the traditional lead single flow batteries using methanesulfonic acid or fluoroboric acid. The new lead single flow battery shows a good cycling performance with an average capacity efficiency of 95% and an energy efficiency of 85% after 500 cycles.