材料期刊网

Effect of Phosphates on the Metal Ion Activated Surface Complexes at the SiO_2-H_2O Interface and in Quartz Deactivation in Flotation System

SUN Zhongxi W. Forsling CHEN Jin Division of Inorganic Chemistry , Lulea University of Technology , S-951 87 Lulea , SwedenDept.of Mineral Engineering , Central South University of Technology , Changsha , 410083 , ChinaTo whom correspondence should be addressed

材料科学技术（英文）

The complexation of phosphates in the quartz-metal ion-H_2O-oleate system was studied. Computer assisted calculations with the aid of the advanced program SOLGASWATER and known equilibrium constants were used to evaluate the mechanism,The calculation results revealed that in the presence of a certain amount of phosphates, metal ions adsorbed at the quartz-H_2O interface will be transferred into solution.Thus the competi- tion for metal ions between phosphates and the quartz surface leads to surface deactivation and re- duced floatability.Various distribution diagrams clearly demonstrate the change of surface complexation as a function of added phosphate concentration.The deactivation products were also evaluated.

关键词: complexation , null , null , null , null , null

A promising sol-gel route to suppress pyrochlore phase during the synthesis of multiferroic Pb(Fe(2/3)W(1/3))O(3) using inorganic salts

Journal of Alloys and Compounds

This paper reports a promising route to synthesize multiferroic Pb(Fe(2/3)W(1/3))O(3) by sol-gel method with inorganic salts of (CH(3)COO)(2)Pb center dot H(2)O, Fe(NO(3))(3)center dot 9H(2)O, and (NH(4))5H(5)[H(2)(WO(4))(6)]center dot H(2)O.The pyrochlore phase was largely suppressed by increasing the calcination temperature, and high purity of perovskite phase was obtained at 725 degrees C which is much lower than the temperature used in other synthesizing processes. Microstructural investigations revealed that the synthesized Pb(Fe(2/3)W(1/3))O(3) particles have cubic morphology and superlattice crystal structure. The formation of Pb(Fe(2/3)W(1/3))O(3) was not sensitive to the pH value of the solution, which is another advantage of this sol-gel method. (C) 2010 Elsevier B.V. All rights reserved.

关键词: Sol-gel;Perovskite;Pb(Fe(2/3)W(1/3))O(3);Pyrochlore;Morphology;mechanical activation;ceramics;transition

The 3rd Word-Wide Symposium on Inorganic Chemistry for Chinese Scientists

稀土学报(英文版)

关键词:

The 3rd Word-Wide Symposium on Inorganic Chemistry for Chinese Scientists

稀土学报(英文版)

关键词:

The 3rd Word-Wide Symposium on Inorganic Chemistry for Chinese Scientists

稀土学报(英文版)

关键词:

The 3rd Word-Wide Symposium on Inorganic Chemistry for Chinese Scientists

稀土学报(英文版)

关键词:

The 3rd Word-Wide Symposium on Inorganic Chemistry for Chinese Scientists

稀土学报(英文版)

关键词:

The 3rd Word-Wide Symposium on Inorganic Chemistry for Chinese Scientists

稀土学报(英文版)

关键词:

Chen系统的状态变量周期性反馈控制

李开明 , 李亚洲 , 冯维贵 , 林长

量子电子学报 doi:10.3969/j.issn.1007-5461.2007.05.014

采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.

关键词: 混沌 , Chen系统 , 不动点 , Lyapunov指数 , 反馈控制

Metal-Free Heterogeneous Catalysis for Sustainable Chemistry

Chemsuschem

The current established catalytic processes used in chemical industries use metals, in many cases precious metals, or metal oxides as catalysts. These are often energy-consuming and not highly selective, wasting resources and producing greenhouse gases. Metal-free heterogeneous catalysis using carbon or carbon nitride is an interesting alternative to some current industrialized chemical processes. Carbon and carbon nitride combine environmental acceptability with inexhaustible resources and allow a favorable management of energy with good thermal conductivity Owing to lower reaction temperatures and increased selectivity, these catalysts could be candidates for green chemistry with low emission and an efficient use of the chemical feedstock This Review highlights some recent promising activities and developments in heterogeneous catalysis using only carbon and carbon nitride as catalysts The state-of-the-art and future challenges of metal-free heterogeneous catalysis are also discussed.

关键词: carbon;catalyst;heterogeneous catalysis;selectivity;sustainable;chemistry;graphitic carbon nitride;modified activated carbon;nanofiber/graphite-felt composite;ordered mesoporous carbons;oxygen;reduction reaction;nitrogen-doped graphite;fuel cell cathode;onion-like carbon;oxidative dehydrogenation;hydrogen-production