材料期刊网

SOLVENT EXTRACTION OF LANTHANIDES IN AQUEOUS NITRITE MEDIA BY CYANEX 302

YUAN Meng , LUO Aiqing , WANG Chun , LI Deqian (Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , Changchun. China Manuscript received 7 November , 1994)

金属学报(英文版)

Solvent extraction of trivalent lanthanides (except for Pm with Cyanex 302 [Bis (2,4,4-trimethylpentyl)monothiophosphinic acid] in heptane was studied at various aqueous pH values, extractant concentrations and different temperatures. Cyanex 302 shows pretty good behaviours on the extraction of lanthanides, especially when extracting heavy lanthanides. However,purified Cyanex 302 exhibits signi ficantly lower extractability to lanthanides than raw extractant. The roles ofdifferent components ofraw Cyanex 302 were discussed to understand the reason of good extractability of the raw extractant. The lanthanides extraction stoichiometry is discussed on the basis ofexperimental results, which can be expressed as follows:

关键词: : Bis(2 , null , null , null , null

EXTRACTION KINETICS OF RARE EARTH (Ⅰ) A Constant Interfacial Cell with Laminar Flow

ZHENG Zhong , LI Deqian (Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , Changchun , China Manuscript received 23 January , 1995)

金属学报(英文版)

A technique was developed to study mass trans fer process and inter facial reaction in two phases system. This constant inter facial cell with a laminar flow was made into a cubic structure. The two fluids were continuously recycled and mixed. The concentration of each liquid could be monitored by two different methods. This kind of structure made both flows near the inter face flow parallel to the inter face. The inter face was smooth and steady. The mass trans fer rate could be judged by the linear velocity of the flows. The technique can be used for the analyses of the control step in both phases near the inter face in a diffusion control process. A preliminary hydrodynamics and mass trans fer study on the cell was presented, which ensures the distinguishing between a diffusion and a chemical reaction control process. A simplified mass transfer equation,N =0.5303D 1 /2* (Ci- Cb)* (V / B) 1/2, was achieved.

关键词: : constant inter face cell , null , null , null

Guangzhou Institute of Energy Conversion,The Chinese Academy of Sciences,Guangzhou 510070,China

B.W. Wang , H. Shen

金属学报(英文版)

Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.

关键词: solar selective thin film , null , null , null

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

SERS and Quantum Chemistry Studies of Adsorption of Thiourea and Ethylthiourea on Silver Electrode

Acta Physico-Chimica Sinica

Adsorption of thiourea (TU) and ethylthiourea( ETU) on roughened silver electrode was investigated using in situ surf. enhanced Raman spectroscopy(SERS) Using quantum chemistry and HSAB theories, the influences of electrode potential and the different substituent groups on SERS were disc i. TU is chemisorbed perpendicularly by Ag-S bond on silver at E = -0.3 V and adsorption of TU turns into a parallel orientation at E = -0.9 V. ETU is always chemisorbed at an angle from Ag. The adsorption of ETU is through and C=C and C=O groups at E = -0.3 V, and mainly through C=C at E = -0.9V.

关键词: Surface enhanced Raman spectroscopy;Adsorption;Quantum chemistry;Thiourea;Inhibitor

LOCAL CHEMISTRY AND THE COHESIVE STRENGTH OF GRAIN BOUNDARIES IN Ni_3Al

Shanthi Subramanian , David Muller , John Silcox and Stephen L.Sass (Department of Materials Science and Engineering and Department of Applied and Engineering Physics , Cornell University , Ithaca. NY 14853)

金属学报(英文版)

Local chemistry plays an important role in determining the cohesive strength of grain boundaries in Ni3Al. Doping with B increases the room temperature ductility and changes the fracture mode from intergranular to transgranular, while doping with Zr increases the ductility but leaves the fracture mode predominantly intergranular.Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDS) were used to probe the changes in local bonding (and hence the cohesive strength) produced by changes in local chemistry at large angle boundaries in Ni3Al.In addition , small angle tilt boundaries were studied to correlate structure with Nienrichment at the interface. B segregation to Ni-rich grain boundaries was shown to make the bonding similar to that of the bulk, thereby increasing their fracture resistance. Ni-enrichment does not occur in the presence of Zr segregation to grain boundaries. Ni-enrichment to antiphase boundaries (APB) in small angle tilt boundaries lowers the APB energy by reducing the number of high energy Al-Al interactions across the interface. Ni-enrichment to large angle boundaries is expected to produce a similar effect on energy.

关键词: : grain boundary chemistry , null , null , null

Effects of Applied Stresses on Martensite Transformation in AISI4340 Steel

ZHAO Hongzhuang , Seokjae LEE , Youngkook LEE , LIU Xianghua , WANG Guodong

钢铁研究学报(英文版)

This study aims at the experimental analysis of the transformation induced plasticity (TRIP) phenomenon. Experiments are conducted in which martensite is allowed to grow under the influence of a series of externally applied stresses. The magnitude of the applied stresses is less than 67% of the yield strength of austenite σγ(Ts). Since there is no obvious difference between the transformation plasticity under tension and the compression for the lower applied stresses, only compressive stresses are applied. The results confirm that the transformation plasticity is proportional to the applied stress if the latter does not exceed 67% of σγ(Ts). The TRIPstrain, the kinetics, and their dependence on the applied stresses are studied. The comparison between calculated results and experimental results shows that the model accurately describes the phenomenon.

关键词: applied stress;TRIP;martensite transformation;lowalloy steel

Influence of applied stress on the gamma ' directional coarsening in a single crystal superalloy

Materials & Design

It was found in a commercial single crystal superalloy CMSX-4 that preferential orientation of the gamma' rafting in dendrite core was not dependent on the sign of the applied stress sigma(A), but on the sign of the sum of the applied stress sigma(A) and a critical equivalent stress sigma(c). This critical equivalent stress sigma(c) caused by material inhomogeneity has been predicted previously; however it was first determined experimentally to be in the range 39.8-47.2 MPa in the present study. Moreover, it qualitatively demonstrated that the critical equivalent stress sigma(c) played a significant role in the creep behavior of superalloys at high temperature and low stress. (C) 2009 Elsevier Ltd. All rights reserved.

关键词: nickel-base superalloy;temperature creep-properties;uniaxial stress;alloy;parameters;morphology;apparent

Kunming Institute of Precious Metals

WANG Yonglu NING Yuantao Kunming Institute of Precious Metals , Kunming , China.

材料科学技术（英文）

关键词:

Influences of externally applied potential on the properties of microscopic particles in nonlinear quantum systems

Physica B-Condensed Matter

When the Schrodinger equation in quantum mechanics is replaced by the nonlinear Schrodinger equation to describe microscopic particles in nonlinear quantum systems, it has been verified that the nature of the particles differs considerably from those in quantum mechanics, where they are localized and have also wave-corpuscle duality due to the nonlinear interactions. In this case the influences of externally applied potentials in the nonlinear Schrodinger equation on the natures of the microscopic particles have been studied by a perturbation theory. The studied results show that the external potential can change the states of the microscopic particles, such as the positions, amplitude and wave forms, but cannot change the wave-corpuscle duality. In the meanwhile, we find further that the relationship between the external potential and change of positions of the particle satisfies the rule of motion of classical particles. Thus we know from this study that the kinetic energy term, ((h) over bar (2)/2m)del(2)phi, in the nonlinear Schrodinger equation can only make the microscopic particles have a wave feature, but the nonlinear interaction b vertical bar phi vertical bar(2)phi determines its corpuscle feature, their combination makes the microscopic particles have a wave-corpuscle duality, and the potential V((r) over right arrow, t)phi changes only the positions, amplitude and wave form of the particles. Therefore the nonlinear interaction plays an important role in determination of the wave-corpuscle duality of microscopic particles in quantum theory. (C) 2010 Published by Elsevier B.V.

关键词: Microscopic particle;Schrodinger equation;External potential;wave-corpuscle duality;Nonlinear interaction;Quantum mechanics;schrodinger-equation