Effect of Additives on Sintering of Cr2O3 in Reductive Atmosphere

The influence of additives TiO2,Y2O3 and composite rare earth on sintering of Cr2O3 in reductive atmosphere was studied.Results show that TiO2 can effectively increase the sinteed density at low temperature,As the increase of sintering temperature,such kind of effect becomes more and more unobvious and finaly disappear at 1550℃.Moreover,Y2O3 and composite rare earth have negative effect on sintering.

NOISE REDUCTION SCHEDULING METHOD IN A SHOP FLOOR AND ITS CASE STUDY

Noise reduction in a shop floor is one of the important parts of greenmanufacturing. In a shop floor machine tools are the main noise sources in a shop floor. A newapproach is discovered by investigation that the noise can be obviously reduced in a shop floor byoptimizing the scheduling between work pieces and machine tools. Based on the discovery, a newmethod of noise reduction is proposed. A noise reduction scheduling model in a shop floor isestablished, and the application of the model is also discussed. A case is studied, which shows thatthe method and model are practical.

Sillimanite,Kyanite and Andalusite in China and Their Applications Part Ⅰ:Their Reserve,Distribution and Characteristics

Sillimanite, kyanite and andalusite are advantageous natural refractory raw materials for aluminosilicate refractories to attain improved key properties. This paper are divided into two parts to introduce their resource and technical characteristic in the first part, and their applications in refractories in the second part to be succeeded . In this part, based on authors ' knowledge and sources , information on their reserve, distribution, composition and characteristic is provided , to bring it to light that China is rich in the reserve of them , in particular andalusite. The sillimanite group minerals are characterized by their phase transformation to form primary mullite and secondary mullite when added in high alumina system , accompanied by volume expansion , which can be taken use to improve creep resistances and thermal shock resistance of the related refractories.

Effect of Fe2O3 Addition in MgO-CaO Refractory on Desulfurization of Liquid Iron

A mathematical model which describes the fluid flow in a gas stirred original ladle and CAS OB ladle was introduced. The fluid field analysis was obtained through mathematical simulation. In order to decrease the ladle refractory wearing and increase the heating speed of liquid steel, some measures should be adopted. The result shows that the flow fields in CAS OB ladle and original ladle are different. With a fixed gas flow rate, the flow field is related to the plug position and the snorkel depth. When the nozzle is located at 0 45 r , where r is the radius of ladle bottom, the fluid field predicted by water modeling is quite satisfactory for improving the quality of liquid steel.

INTRAGRANULAR FERRITE FORMED IN ASSOCIATION WITH INCLUSIONS IN A VANADIUM MICROALLOYED STEEL

Intragranular ferrite was formed at inclusions in a vanadium microalloyed steel with excess amount of sulfur. The chemical composition of inclusions in the steel was analyzed by SEM-EDS. The inclusions were mainly composed of MnS and aluminum oxides. The precipitation of MnS at aluminum oxides might result in Mn depletion, which, in turn, pro- motes the formation of intragranular ferrite. Optical and SEM observations and three- dimensional (3D) reconstruction demonstrated that intragranular ferrite was formed at inclusions. The morphology of intragranular ferrite changed with undercooling. At higher temperatures intragranular ferrite was nearly equiaxed whereas it was plate-like or lath-like at lower temperatures.

Pure metal extraction from molten oxide slag by short-circuit galvanic cell

The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]Fe+C saturation|ZrO2(MgO)|(FeO)(slag)|Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.

Theory of Volumetric Moving Dislocation in Poroelastic Halfspace and Characterization of Magma Intrusion Events

The undrained change in pore fluid pressure that accompanies dike intrusion may be conveniently represented as a moving volumetric dislocation. The concept of a dilation center was developed to represent the field of undrained pressure change in a saturated linear elastic medium. Since instantaneous pore fluid pressures can be developed to a considerable distance from the dislocation, monitoring the rate of pressure generation and subsequent pressure dissipation in a fully coupled manner enables certain characteristics of the resulting dislocation to be defined. The principal focus of this study is the application of dislocation based methods to analyze the behavior of the fluid pressure response induced by intrusive dislocations in a semi infinite space, such as dike intrusion, hydraulic fracturing and piezometer insertion. Partially drained pore pressures result from the isothermal introduction of volumetric moving pencil like dislocations described as analogs to moving point dislocation within a semi infinite saturated elastic medium. To represent behavior within the halfspace, an image dislocation is positioned under the moving coordinate frame fixed to the front of the primary moving dislocation, to yield an approximate solution for pore pressure for constant fluid pressure conditions. Induced pore pressures are concisely described under a minimum set of dimensionless parameter groupings representing propagation velocity, and relative geometry. Charts defining induced pore fluid pressure at a static measuring point provide a meaningful tool for determining unknown parameters in data reduction. Two intrusive events at Krafla, Iceland are examined using the type curve matching techniques. Predicted parameters agree favorably with field data.

INFLUENCE OF TIN ON THE HOT DUCTILITY OF A LOW-CARBON STEEL

The influence of tin on the hot ductility of a 0.15wt%C steel is investigated using a continuous-casting thermal simulator with three cooling rates. Tin can apparently deteriorate the hot ductility of the steel. Non-equilibrium grain boundary segregation of tin occurs during cooling and plays an important role in reducing the hot ductility of the steel. There is a critical cooling rate for the Sn segregation being between 5 and 20K/s.

An Ontology-Based Representation Architecture of Unstructured Information

Integrating with the respective advantages of XML Schema and Ontology, this paper puts forward a semantic information processing architecture-OBSA to solve the problem of heterogeneity of information sources and uncertainty of semantic. It introduces anF-Logic based semantic information presentation mechanism, presents a design of an ontology-based semantic representation language and a mapping algorithm converting Ontology to XML DTD/Schema, and an adapter framework for accessing distributed and heterogeneous information. Key words ontology - F-Logic - semantic adapter CLC number TP 391 Foundation item: Supported by the Natural Science Fundation of Hubei of China (2003ABA049) and the Natural Science Fundation of Education Agency of Hubei of China (2003A012)Biography: GU Jin-guang (1974-), male, Ph. D candidate, lecturer, research direction: distributed computing system, software engineering and knowledge engineering.

EFFECTS OF COPPER ION IMPLANTATION ON ANTIBACTERIAL ACTIVITY OF AISI420 STAINLESS STEEL

Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2.0×1017ions·cm-2. The saturation dose of Cu implantation in AISI420 SS and Cu surface concentration were calculated at the energy of 100keV. The effect of dose on the antibacterial activity was analyzed. Results of antibacterial test show that the saturation dose is the optimum implantation dose for best antibacterial activity, which is above 99% against both Escherichia coli and Staphylococcus aureus. Novel phases such as Fe4Cu3 and Cu9.9Fe0.1 were found in the implanted layer by glancing angle X-ray diffraction (GXRD). The antibacterial activity of AISI420 SS attributes to Cu-contained phase.

Preparation and Anti-Oxidation Properties of Ti(CN) Films Deposited by P CVD

Using metallo-organatic compound TPT as the source of Ti, H13 mould steels were coated with Ti(CN) films by plasma-assisted chemical vapor deposition (PCVD) and the properties of Ti(CN) films were studied. Under the appropriate temperature and pressure, Ti(CN) films on H13 mould steel surfaces had the highest micro-hardness of HV1760 at 500°C, and the films showed excellent anti-oxidation property below 500°C. The lifetime of Ti(CN)-coated augers and dies could be enhanced 7 and 4 times longer than those of untreated respectively.

Determination of Neutron Irradiation-Induced Phosphorus Segregation on Grain Boundaries in a P-doped 2.25Cr1Mo Steel

Irradiation-induced impurity segregation to grain boundaries is one of the important radiation effects on materials. For this reason, phosphorus segregation to prior austenite grain boundaries in a P-doped 2.25Cr1Mo steel subjected to neutron irradiation is examined using field emission gun scanning transmission electron microscopy (FEGSTEM) with energy dispersive X-ray microanalysis (EDX). The steel samples are irradiated around 270 and 400℃, respectively. The irradiation dose rate and dose are -1.05×10-8 dpa/s and -0.042 dpa respectively for 270℃ irradiation, and 1.7×10-8 dpa/s and 0.13 dpa respectively for 400℃ irradiation. The FEGSTEM results indicate that there is no apparent phosphorus segregation during 270℃ irradiation but there is some during 400℃ irradiation.

Synthesis and Characterization of Nanoscale Mullite Powder

Nanoscale mullite powder were synthesized via Sol-gel-SCFD and middle temperature treatment by using AIP( aluminum-isopropoxde) and TEOS ( tetraethyl orthosili-cate) as starting materials. Both of the binary aerogel of alumina-silica and calcined nanoscale materials were investigated by using TG-DSC ( thermogravimetry-differentialscanning calorimeter) , TEM( transmission electron microscope) , XRD(X-Ray diffractometer ) and specific surfacearea and porosimetry. TG-DSC indicated the removal of most of the volatiles, i.e. 15.98% up to about 700℃ ,and in the DSC curve , existence of two exothermic peak atabout 445℃ and 1015℃ may be due to the crystallizationof Si-O-Al-O in diphasic gels and mullitization and a small endothermic peak at about 805℃ indicated the decomposition of structural water molecules . On the colligation of the results of TG-DSC, XRD and TEM, the beginning temperature of mullitization in Al2O3-SiO2 aerogel system can be confirmed at about 1015℃. XRD results also showed the formation of mullite at the range 1100-1200℃. TEM and surface area and porosimetry results showed that the nanosized mullite were calcinated at 1100and 1200℃ exhibited size 30 nm and 50 nm, specific surface area 138.91 m2/g and 95.81 m2/g.

RESEARCH ON CHEMICAL COMPOSITION AND MICROSTRUCTURE OF NEWLY-DEVELOPED HIGH STRENGTH AND HIGH ELONGATION STEELS

The different chemical composition of silicon and manganese as well as different retained austenite fraction ranged from 4% to 10% of the high strength and high elongation steels were studied in the paper. The dislocations and carbon concentration in retained austenite were observed by a transmission electron microscope and an electric probe analyzer, respectively. The experimental results showed that silicon and manganese are two fundamental alloying elements to stabilize austenite effectively but retaining austenite in different mechanisms. Meanwhile, the cooling processing played an important role in controlling the fraction of retained austenite of the hot-rolled high strength and high plasticity steels.

EFFECT OF COPPER IMPLANTATION ON ANTIBACTERIAL ACTIVITY OF AUSTENITIC STAINLESS STEEL

Antibacterial activity has been studied by copper ion implantation into 0Cr18Ni9 stainless steel. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 60-100keV energy and a dose range (0.2-2.0)×1017 ions cm-2. Saturation doses, surface concentration were calculated and the relationships between energy, dose and antibacterial activity were analyzed. Novel phases such as Fe4Cu3 and Cu0.81Ni0.19 were found after copper implantation by X-ray diffraction. The novel phases, effects on antibacterial activity have been investigated. The results show that saturation dose varies with the ions' energy. Antibacterial activity has close relation with copper,s concentration in implanted layer and Cu-rich phase.

Slab Storage Calculation Method for Continuous Casting-Hot Rolling

Based on load-oriented manufacturing control theory,different combining modes and slab storage calculation method for continuous casting and hot rolling were discussed.The buffer capacity index of continuous casting-rolling was introduced,and the reasonable slab storage under different combining modes was calculated with buffer capacity index of 120.00 hfor CCR,79.20 hfor HCR,19.68 hfor DHCR and 3.84 hfor DR.Thin slab is 1.20 h,and the strip is zero.Theory gist was provided for steel enterprise to decrease storage.

Antibacterial Property of Martensitic Stainless Steel Generated by Cu Ion Implantation

Copper ions were implanted into a AISI420 martensitic stainless steel (SS) by metal vapor vacuum arc (MEVVA) with a dose range 0.2 xlO17 -S.OxlO17 cm"2 at the energy of lOOkeV. The Cu-implanted stainless steel was treated by a special antibacterial treatment subsequently. The phase compositions in the implanted layer were studied by glancing X-ray diffraction ( GXRD) and changes of bacterial appearance on the surface of Cu un-implanted SS and Cu-implanted SS with antibacterial treatment SS were observed by bio-TEM (transmission electron microscopy) separately. The results showed that a suitable amount of Cu-rich phase was dispersed in the implanted layer of Cu-implanted SS that was treated by special antibacterial treatment. So the Cu-implanted martensitic stainless steel with antibacterial treatment reveals excellent antibacterial property against both E. coli and S. aureus.

PHOSPHORUS GRAIN BOUNDARY SEGREGATION IN A P-DOPED 2.25Cr1Mo STEEL

Grain boundary segregation of phosphorus during tempering at 540℃ after quenching from 980℃ is examined for a P-doped 2.25Cr1Mo steel by means of Auger electron spectroscopy. The solute-boundary binding energy and the diffusion coefficient for phosphorus are determined by virtue of the measured segregation kinetics along with the equilibrium segregation theory. The obtained values of the above parameters are discussed with comparison to those found in the literature for low-alloy steels.

Effect of manganese on heat stress protein synthesis of new-born rats

AIM: To study the effect of manganese (Mn) on heat stressprotein 70 (HSP70) synthesis in the brain and liver of new-bom rats whose mother-rats were exposed to Mn.METHODS: 32 female rats were randomly divided into fourgroups. One group was administrated with physiologicalsaline only as control group, the other three groups wereadministrated with 7.5, 15 and 30 mg@ kg-1 manganesechloride (MnCl2) by intraperitioneal injection every two daysfor two weeks. After delivery, the mother-rats receivedMnCl2 unceasingly for a week with the same method. Thenthe contents of Mn、 Zn、 Cu and Fe in the livers of the new-bom rats were determined by atomic absorptionspectroscopy; The level of HSP70 in the brains and thelivers of the new-born rats as detected by Westsrn-dot-blotting, and the SOD activities were measuredsimultaneously.RESULTS: The contents of Mn in the livers of new-bom ratsof the experimental groups(respective 1.38 ± 0.18, 2.73 ±0.65, 3.44 ± 0.89μg @ g-1) were significantly increasedcompared with the control group(0.88 ± 0.18μg@ g-1; p ＜0.01); The contents of Fe in the livers of new-bom rats of 15and 30 mg@ kg-1 experimental groups (426 ± 125,572 ± 175μg@g-1, respectively) were significantly increased comparedwith the control group(286±42μg@g-1; P＜0.05); the levelsof Zn in the livers of the new-bom rats of three experimentalgroups( 254 ± 49, 263 ± 47, 213 ± 28μg@ g-1, respectively)were lower than those of the control group(335 ± 50μg@g-1;respective P＜0.05, P＜0.01); and the levels of Cu showedno significant difference among the four groups (threeexperimental groups: 75 ± 21, 68 ± 241 and 78 ± 18μg@g-1;control group: 83 ± 9μg@ g-1; p ＞ 0.05). There was asignificant increase in the levels of HSP70 in the brains ofnew-bom rats of the 30 mg@kg-1 group (19.5 × 103 ± 1.3 ×103A; control group: 14.3 × 103 ± 1.4 × 103A; P＜ 0.01),andthe levels of HSP70 in the livers of new-bom rats of threeexperinental groups(respective 19.6 × 103 ± 3.9 × 103A, 18.5× 103 ± 3.8 × 103A, 22.4 × 103 ± 1.9 × 103A ) also increasedthan control group(13.3 × 103 ± 1.0 × 103A; P ＜ 0.01), butthe SOD activities showed no significant difference amongbrains of the four groups (experimental groups: 5.04 ± 0.43,4.83±0.48, 4.60±0.84 ku@g-1; control group: 4.91 ± 0.37ku@g-1; P＞ 0.05). The SOD activities in the livers of 15mg@kg-1 group(5.41 ± 0.44 ku@g-1) was lower than the controlgroup(5.95±0.36 ku@g-1; P＜0.05).CONCLUSION: While mother-rats were exposed tomanganese, the metabolisms of Mn、Zn and Fe of new- bornrats in the livers were influenced and were situated in astress status, thus HSP70 syntheses is induced in the brainsand livers of new-bom rats, but the mechanism of this effectin the developmental toxicity of Mn remains to he furtherstudied.