Isothermal decomposition behavior of the high nitrogen concentration γ-Fe[N] prepared from pure iron

The isothermal decomposition characteristic of the homogeneous high nitrogen austenitic samples prepared by a new multi-stage nitriding process was investigated by SEM and TEM in this paper. Lamellar-structure precipitations arranged on the decomposed austenite grain boundaries (GBs) and the flaky γ′ particles and network-structure precipitations appeared inside of the γ matrix. The extra high Vickers hardness more than 800 HV was found in the 5-h aged samples, which was different from those of the bainitic/martensitic structures in Fe-C alloys. The SAED analysis indicates the γ′ has the coherent relation with the parent γ-Fe[N] phase and the interstitial nitrogen atoms are inclined to aggregate on {1 1 0}γ′/γ planes, which also contributes to the hardness of the matrix.     

液晶的激光拉曼光谱研究——Ⅰ.十九种液晶的固相激光拉曼光谱

本文报道联苯、联苯酯、单酯、双酯、Schiff碱和氧化偶氮苯型十九种液晶化合物的固相激光拉曼光谱,讨论了2300～400 cm~(-1)范围内基团的特征谱带归属以及光谱与结构之间的关系.     

RuIII@CMC/Fe3O4 hybrid: an efficient,magnetic, retrievable,self-organized nanocatalyst for green synthesis of pyranopyrazole and polyhydroquinoline derivatives

Molecular Diversity - RuIII incorporated with magnetic nanosized CMC/Fe3O4 hybrid (RuIII@CMC/Fe3O4) has readily developed by a very simple self-organized procedure of RuCl3 and Na–CMC/Fe3O4...     

Free-standing crystalline CaCO3 films composed of three-dimensional microstructures with different morphologies

Crystalline vaterite CaCO₃ self-standing films composed of three-dimensional microstructures were synthesized by a simple gas diffuse method with the assistance of poly(vinyl alcohol) (PVA). The microstructures with different morphology (sphere-like, rose-like, and pumpkin-like) were self-assembled by three-dimensional oriented attachment of faceted micro-platelets, and the films were all stable in air for more than one year. The concentrations of Ca²⁺ ions and PVA all played important roles in the formation of vaterite crystal phase. In addition, the introduction of salt (NaCl, NaNO₃) would reduce the size of the micro-platelets significantly. A possible mechanism for the formation of the self-standing films is put forward.     

Synthesis of nano-LiFePO4 particles with excellent electrochemical performance by electrospinning-assisted method

Nanoscale LiFePO₄/C particles are synthesized using a combination of electrospinning and annealing. The important advantages of electrospinning technique are the production of separated nanofiber precursor, enabling the precursor particles arrangement to be changed, impeding the growth and agglomeration of the LiFePO₄ particles during the heat treatment, and contributing to the formation of nanosized LiFePO₄ particles. In this study, polyvinylpyrrolidone (PVP) is used as the fiber-forming agent in the electrospinning method, and also provides a reducing agent and carbon source. In situ carbon-coated LiFePO₄ particles are obtained by the pyrolysis of PVP during the thermal treatment. The LiFePO₄ particles are coated with and connected by interlaced carbons, and are uniformly distributed in the size range 50–80?nm. It is found that the as-prepared nanoscale LiFePO₄/C composite has a desirable electrochemical performance. It has discharge capacities of 163.5?mA?h g^?1 and 110.7?mA?h g^?1 at rates of 0.1?C and 10?C, respectively. In addition, this cathode has excellent cyclability with a capacity loss of less than 3?% at 0.1?C and 5?% at 5?C after 500 cycles. An effective synthesis and processing method is presented for obtaining nanosized LiFePO₄ with high electrochemical performance.     

Fabrication and characterizations of oligopyrrole doped with dodecylbenzenesulfonic acid in reverse microemulsion

The pyrrole-oligomer nanoparticles doped dodecylbenzenesulfonic acid (DBSA) have been fabricated in water-DBSA-isopropyl alcohol-isooctane reverse microemulsion, since DBSA could play the roles of both surfactant and dopant. We have found the optimum synthetic conditions by the analysis of factors affecting the yield and conductivity of oligopyrrole. The effect of solubility on the improved properties of DBSA-oligopyrrole in some organic solvents was studied employing UV-vis-NIR spectroscopy. This indicates that doping and pyrrole-oligomers may improve the poor processibility of PPy. Its environmentally stable properties were characterized by thermogravimetric and differential thermal analysis (TG-DTA). The maximum room temperature conductivity of products is 8.01 S/cm using the four-probe technique. The pyrrole-oligomers have been determined by the analysis of molecular weight measurement, and X-ray photoelectron spectroscopy (XPS) and elemental analysis were employed to investigate the formation of DBSA-oligopyrrole complexes. Correspondingly, the structural properties of DBSA-oligopyrrole were studied by infrared spectroscopy (IR), X-ray diffraction (XRD), transmission electron micrographs (TEM), and scanning electron microscopy (SEM).     

Synthesis and Electrochemical Properties of a Novel Poly(ether sulfone) with Oligoaniline Pendants

A novel poly(ether sulfone) with oligoaniline pendants(PESOP) was prepared by K₂CO₃-mediated nucleophilic polycondensation and characterized with Fourier-transform infrared spectrometry(FTIR), ¹H nuclear magnetic resonance(¹H NMR) and gel permeation chromatography(GPC). The cyclic voltammetry(CV) curve of PESOP reveals the reversible electroactivity. In the electrochromism study, PESOP film exhibited good electrochromic properties with a high contrast value, moderate switching time and acceptable coloration efficiency. After running 1000 cycles, the PESOP/indium-tin oxide(ITO) electrochromic device remained unchanged except for the drifting of base line, which certified its good electro-photo stability of the fabricated electrochromic device. Moreover, the polarization technique and electrochemical impedance spectroscopy(EIS) were used to study the anticorrosion performance of PESOP coatings on the cold rolled steel(CRS) in a 5%(mass fraction) NaCl solution. All the results indicate that the obtained PESOP is a competitive candidate as anticorrosion material.