INFLUENCE OF NON-PROCESS ELEMENTS ON REED PULP'S CHARACTERS DURING OXYGEN DELIGNIFICATION

A series of Reed Pulps were prepared in which the level of Non-Process Elements(NPEs), including calcium, manganese,copper,iron were seclectively enriched and depleted, these pulps were then oxygen delignification,and the pulps were characterized according to kappa number,viscosity,brightness. The results indicated that the enrichment of NPEs have an important effulence on delignification,pulp viscosity and brightness, iron is the most harmful during oxygen delignification but manganese is just like a kind of aid and can enhance brightness and delignification.

Rare-Element Pegmatites Rocks Rich and Li of the Aïr Massif of the Tchirozerine: Mineralogy and Chemical Composition Agadez Region-Northem Niger

The lithium potential in the Aïr massif is represented by mineral index of spodumene pegmatites and, lepidolite pegmatites. The mineral deposits of lithium occur in cluster or veins that cut the host rock or are located near the contact between the greenstone belt and granitic massif. The evidence of lithium is in the form of clusters or disseminated and stockwerk. Mineralogical characteristics show similarities between the Air Massif pegmatites and indicate the same homogenous source during the magma-generation process. The pegmatite rocks attracted the attention due to their wide exposure and composition, well appearance, and economically hosting of significant rare earth metals such as Sn and W. The mineralogical and petrographical investigations on the eight pegmatites rocks samples observed have a relative similarity, while a little difference in the shapes attributed to the ratio in the pegmatite rocks of the minerals. The occurrence of the kink band indicates the influence of the tectonic processes which affected the Aïr massif after the emplacement of late magmatic or post-magmatic pegmatites by injection into fractured rocks in the upper part of the crust. The Air Massif pegmatite has higher concentrations Li and of all trace elements except Hf and occasionally Zr, Ti, Sn and Mg of for the economic exploration.

Processing TiAl-Based Alloy by Elemental Powder Metallurgy

TiAI-based alloys with various compositions (including Ti-48Al, Ti-47Al-2Cr-2Nb, Ti-47Al-2Cr-2Nb-0.2B and Ti-47Al-3Cr, in mole fraction) had been prepared by elemental powder metallurgy (EPM). The results have shown that the density of the prepared Ti-48AI alloy increases with increasing hot pressing temperature up to 1300℃. The Ti-48AI alloy microstructure mainly consisted of island-like Ti3Al phase and TiAl matrix at hot pressing temperature below 1300℃, however, coarse α2/γ lamellar colonies and γ grains appeared at 1400℃. It has also indicated that the additions of elemental Cr and B can refine the alloy microstructure. The main microstructural inhomogeneity in EPM TiAI-based alloys was the island-like α2 phase or the aggregate of α2/γ lamellar colony, and such island-like structure will be inherited during subsequent heat treatment in (α＋γ) field. Only after heat treatment in a field would this structure be eliminated. The mechanical properties of EPM TiAl-based alloys with various compositions were tested, and the effect of alloy elements on the mechanical properties was closely related to that of alloy elements on the alloy microstructures. Based on the above results, TiAI-based alloy exhaust valves were fabricated by elemental powder metallurgy and diffusion joining. The automobile engine test had demonstrated that the performance of the manufactured valves was very promising for engine service.

The exact solution of Stokes' second problem including start-up process with fractional element

The start-up process of Stokes＇ second problem of a viscoelastic material with fractional element is studied. The fluid above an infinite flat plane is set in motion by a sudden acceleration of the plate to steady oscillation. Exact solutions are obtained by using Laplace transform and Fourier transform. It is found that the relationship between the first peak value and the one of equal-amplitude oscillations depends on the distance from the plate. The amplitude decreases for increasing frequency and increasing distance.

Effect of alloying elements on austempered ductile iron(ADI) properties and its process:Review

Austempered ductile iron(ADI) parts have a unique combination of high strength and toughness with excellent design flexibility and low cost. These excellent properties are directly related to its microstructure called "ausferrite" that is the result of austempering heat treatment applied to ductile irons. Alloying elements increase ADI austemperability and change speeds of austempering reactions. Thus, they can affect ADI resultant microstructure and mechanical properties. In this paper, the effects of alloying elements on ADI mechanical properties, microstructural changes, two-stage austempering reactions, processing windows, austemperability, and other aspects are reviewed.

Effect of alloying elements and processing parameters on the Portevin–Le Chatelier effect of Al–Mg alloys

The effects of alloying elements and processing parameters on the mechanical properties and Portevin-Le Chatelier effect of A1-Mg alloys developed for inner auto body sheets were investigated in detail. Tensile testing was performed in various Zn and Mg contents under different annealing and cold-rolling conditions. In the results, the stress drop and reloading time of serrations increase with increasing plastic strain and exhibit a common linear relationship. The increase rates of stress drop and reloading time increase with increasing Mg or Zn content. The alloys with a greater intensity of serrated yielding generally exhibit a greater elongation. The stress drop and reloading time of serrations decrease with increasing grain size in the case of the annealed samples. The cold-rolled sample exhibits the most severe serra- tion because it initially contains a large number of grain boundaries and dislocations.

Geochemical Features of Trace and Rare Earth Elements of Pumice in Middle Okinawa Trough and Its Indication of Magmatic Process

Pumice,the most widely distributed volcanic rock in Okinawa Trough,is loose and porous.Since its formation,it has definitely suffered from the denudation of the sea to different degrees.In order to truly reveal the geochemical features of pumice,we choose the method of mineral separation.Firstly,the phenocryst is separated from glass.Then the phenocryst is divided into light and heavy mineral compositions.By ICP-MS(inductively coupled plasma mass spectrometry) analytical technology,the contents of trace and rare earth elements in the whole pumice,the glass and the heavy and light mineral compositions are determined respectively.By researching the elemental geochemical features,the magma dynamic processes are found.It shows that the initial magma for the pumice in Okinawa Trough came from the depleted mantle,from which the N-MORB(normal type of mid-ocean ridge basalt) is formed,homologous with the local basalts.But they are formed in different periods of magma crystal fractionation.Featured with sufficient crystal fractionation for pumice,it is found that the earlier crystallizing minerals are olivine,plagioclase and pyroxene.The pumice magma,formed from the depleted mantle,was mixed with additional subduction-related materials(components),and contaminated with the mass from upper crust when it rose up into the crust.As the Okinawa Trough is a back-arc basin in its early back-arc spreading stage,its magmatism has a series of its own unique characteristics,different from not only the mid-ocean ridge expansion,but also the mature back-arc basin.

Hydroforming Process Design Using Finite Element Simulation for a Vehicle Instrument Panel Support Frame

Tubular hydroforming has attracted increased attention in the vehicle industry recently. This paper covers a complete hydroforming process design for an instrum ent panel frame by finite element simulation using the explicit code LS-DYNA. The manufacturing process for the instrument panel frame consists of tube pre-be nding and final hydroforming. To accomplish hydroforming process design successf ully, a thorough investigation of proper combination of process parameters such as internal hydraulic pressure and axial feeding is carried out by finite element simulation to predict the tube wall thickness and shape. An optimized process parameter combination is obtained and verified by the instrument panel frame hyd roforming experiment. The experiment shows that designed process parameters can be used in real production through FEA simulation, but tubular thinned amplitu de by FEA is less than that with the experiment.

PREPROCESSING AND POSTPROCESSING SYSTEM FOR FINITE ELEMENT COMPUTATION

研究了有限元计算中的单元自动划分、曲线处理、节点疏密处理、载荷自动分布、与优化设计的衔接和等应力线绘制等方面的技术问题，阐述了有限元平面八节点单元前后置处理软件的设计过程。

Distribution Characteristics of Minerals and Elements in Chromite Ore Processing Residue

In this paper,environmental scanning electron microscopy (ESEM) is applied to characterizing the mineral and element distribution of chromite ore processing residue (COPR).The test results show that Cr-bearing brownmillerite occurs in the rim of COPR particle,while hydroandradite with Cr(Ⅵ) in its structure presents inside the COPR particle.Periclase and calcite occur in the interstitial area.Element analyses show that Ca,Fe and Al are distributed throughout the COPR particle,and Mg exists mostly in the interstitial area or on the particle surface.A lower content of Cr is evenly distributed in the COPR particle,while slightly higher concentration of Cr occurs inside the particle.It is suggested that it will take a relatively longer time for Cr to migrate out of COPR,especially for hexavalent chromium,so the leaching time and the particle size may be two important factors to affect the release of Cr(Ⅵ).

Behaviours of Main Elements in Soil-Forming Processesof Fildes Peninsula, the Maritime Antarctic

INTRODUCTIONFildesPeninsula(62"12'S,58o58'W)ofKingGeorgeIsland,theSouthShetlandIslands,measuresabout3.5kmfromeasttowest,and7.5kmfromnorthtosouth.ThetypicalmaritimeAntarcticclimatemakesthePeninsulaoneofthewarmestandmoistestregionsinAntarctica.Accordin...

Finite element analysis of the end cutting process for U-section parts with high-strength steel

This paper presents a constitutive framework for finite element analysis of the truck beam end cutting process.For this purpose,a finite strain anisotropic elasto-plastic model,which takes nonlinear kinematic and isotropic hardening into account,is presented.Three factors are investigated to determine the effect on cutting quality:radius of cutting tools,strength of materials and relative clearance in cutting.The recommendations made herein are based on the simulation results.

Preliminary Study on Element Leaching and Current Soil-Forming Process of Red Soils

The leaching characteristics and the element concentration in soil solution of red soils derived from sandstone,granite,Quaternary red clay and basalt have been studied in the Red Earth Ecological Experimental Station,Academia Sinica,using 12 lysimeters.Results obtained show that the element leaching process of red soils occurs mainly from January to the beginning of July annually.The elements with higher concentration in leaching solution of red soils are Si,Ca,Na,K,Mg,and N.The desilication and the leaching process of base cations occur simultaneously in the red soils.Using the first order differential equation and measured parameters of Si leaching,the leaching models of Si for red soils derived from different parent materials are constructed.The leaching process of Si is simulated with the models.Both the absolute and relative ages of red soils derived from different parent materials are discussed based on the simulation result.On the basis of element leaching,composition of soil solution and thermodynamics,the current soil-forming process is discussed.According to the phase diagram,the kaolinization is prevailing in the current formation of different red soils.

A Model for the Design Process Gene Based on the Extensible Basic-element and the Mutation of the Design Process Gene

In this paper a method is developed to model the design process gene based on the extensible basic-element with the purpose of design process optimization and reuse. First, the principle of genetic engineering based design process optimization and reuse is put forward and analyzed. Second, the extensible basic-element model of the design process gene is established based on the models of the design process base and the base pair through analyzing the concept and structure of the design process gene and the extensible basic-element as well as its extensibility. Third, the features of divergence and scalability of the extensible basic-element model of the design process gene are discussed for carrying out the extension translation to the design process gene by way of inserting, deleting and updating design process bases. Finally, an example of building extensible basic-element models for the design process base, base pair and design process gene in mechanical product design and the mutation process of the design process gene in airplane design is presented which demonstrates the application of the method proposed in this paper.

OPTIMIZATION OF AUTOBODY PANEL STAMPING PROCESS BASED ON DYNAMIC EXPLICIT FINITE ELEMENT METHOD

Taking CPU time cost and analysis accuracy into account, dynamic explicit finite ele- ment method is adopted to optimize the forming process of autobody panels that often have large sizes and complex geometry. In this paper, for the sake of illustrating in detail how dynamic explicit finite element method is applied to the numerical simulation of the autobody panel forming process,an example of optimization of stamping process pain meters of an inner door panel is presented. Using dynamic explicit finite element code Ls-DYNA3D, the inner door panel has been optimized by adapting pa- rameters such as the initial blank geometry and position, blank-holder forces and the location of drawbeads, and satisfied results are obtained.

Analytical solutions for the slow neutron capture process of heavy element nucleosynthesis

In this paper, the network equation for the slow neutron capture process （s-process） of heavy element nucleosynthesis is investigated. Dividing the s-process network reaction chains into two standard forms and using the technique of matrix decomposition, a group of analytical solutions for the network equation are obtained. With the analytical solutions, a calculation for heavy element abundance of the solar system is carried out and the results are in good agreement with the astrophysical measurements.

Change law of real vapor pressure of Al element in Ti-xAl (x=25～50) melt during ISM process

A new model was established to calculate the real vapor pressure of the Al element in the molten Ti x Al ( x = 25 ～ 50, mole fraction, %) alloy. The effects of the holding time, chamber pressure, mole fraction of Al and melting temperature on the real vapor pressure of Al element in the vacuum chamber were analyzed. Because of the impeding effect of the real vapor pressure on the evaporation loss rate, within a short time (less than 10?s), the real vapor pressure tends to a constant value. When the chamber pressure is less than the saturated vapor pressure of the Al component, the real vapor pressure of Al is equal to the chamber pressure. While when the chamber pressure is larger than the saturated vapor pressure, the real vapor pressure is equal to the saturated vapor pressure of the Al element of the same condition.

二硫化钼自润滑涂层性能及制备工艺的研究进展

MoS_(2)是过渡族金属二硫化物中的一员,其涂层材料因独特的层状结构而表现出优异的摩擦学性能。MoS_(2)自润滑涂层在刀具以及空间部件材料的表面减磨和保护上发挥着重要作用,但是MoS_(2)涂层对湿度的敏感性、附着力差以及耐磨寿命有限等问题限制了其应用。国内外学者在MoS_(2)涂层的摩擦学研究上做了大量工作,目前的研究重点主要是不同温度、湿度、气体介质的多环境下的摩擦学行为分析,以及通过纳米多层体系的设计实现对晶体结构的可控。本文概述了2010年以来有关MoS_(2)自润滑涂层材料的研究进展,主要综述了MoS_(2)自润滑涂层的摩擦学性能以及不同元素掺杂对其性能和结构的影响。总结了MoS_(2)涂层的组成结构、性能、制备工艺,并对其在表面润滑领域的研究和应用前景进行了展望。本文对MoS_(2)自润滑涂层的研究和工程应用具有参考意义。