Abstract: According to the reinforcement plan on No.2 main ore-pass of Cheqchao iron mine by the method of support funnel, it is analyzed by numerical simulation that is the stability in the mechanical state of surrounding rock and the local and whole structure before and behind reinforcement, The calculation result presents the theoretical basis for the choice and confirmation of the whole reinforcement plan.
Abstract: The mechanism of dewater equipment on wet scrubbers is analyzed in detail. The characteristic of dewater equipment is experimentally studied. The empirical and semiemptrical formulae of the relations between the wet resistance coefficient and critical velocity of dewater equipment and the liquid-gas ratio are set up. It provided theoretical base and experimental data for other kinds of dewater equipment.
Abstract: A large number of experiments, research on the effects of regular cracks to macro-mechanical properties in rock like materials, such as high strength gypsum and white cement, under uniaxial compression are conducted. The experimental relationships of the macro-equivalent strength σe, elastic modulus Ee and passion's ratio μe versus the inclined angle of cracks α are obtained. The specificity curve of σe-α, also depending on cracks density h, for multi-crack body is given by the analysis of experimental and theoretical results. The data and conclusion will be useful for mining industry and some other underground engineering.
Abstract: The relationship between the foam height and time has been measured for foaming processes caused by reducing Fe2O3 in smelting reduction synthetic slap. The foam behavior parameters under different condition were determined by means of experimental results and foam behavior equations. In this way, the foaming process caused by reducing Fe2O3 in smelting reduction process could be described quantitatively. The results provide necessary basis for controlling the foam phenomenon in iron bath.
Abstract: The Kinetic model of powder injection desulphurization refining process with the ladle-immersion cover was invsetigated. Effect of original sulphur and top slap and slag mass on desulphurization was studied. The result show that the finishing sulphur content by calcultation model is consistent with experiment result. The model calculate result conduced to instituted test scheme and prepared industrial test.
Abstract: A general Technology Screening Mechanism(TSM) for the cleaner production of metallurgical industry was presented and a cost appraisal model for economic consideration was described in the TSM. The practical usefulness of the cost model is shown with a case study in steelmakihg by the electric arc furnace.
Abstract: The aging process of the spray-deposited Al-20Si-5Fe-3Mn-3Cu-1Mg alloy was investigated by DSC analysis, microhardness measurement, TEM and HREM observations. The results show that two kinds of precipitates, S-Al2CuMg and σ-Al5Cu6Mg2 precipitate from matrix and improve the tensile strength of the alloy efficiently at both the ambient and elevated temperatures (300℃).
Abstract: The a analogitiy of fast transient heat conduction and mass diffusion is analyzed in physical mechanisms and mathematical formulations etc. Theoretical and experimental results both indicate the fast transient heat conduction and mass diffusion have analogous physical behavior-fluctuation mechanism and same mathematical formulations. The dimensionless numberand Hh and Hm, as well as their effects on the distributions of temperature and concentration are given out by theoretical analysis and nuxnerical simulation. Meanwhile, the dimensionless number H1 (H1=$\frac{{{H_h}}}{{{H_m}}}$) is also defined, which reflects the identical extent of temperature and concentration distributions.
Abstract: The hot deformation characterishcs of Q235 class low carbon steel were investigated by plane strain compression test within the temperature range between 550℃ and 720℃, i.e. ferrite phase range, with a strain rate range of 5×10-4 s-1 to 10s-1. The experimental results show that, in the ferrite phase range, the flow wstresses of strain-stress curves gradually increases to a peak followed by a strain softening and then a steady state at high strain, indicating that dynamic recovery or dynamic recrystallization occurs in the steel. The slower the strain rate, and/or the higher the deformation temperature, the smaller the strain corresponding to the peak stress. The hot deformation activation enemy (Q) of the steel tested is calculated to be 300.4 kJ/mol from the values of Zener-Hollomon parameters and peak stresses.
Abstract: The behavior of corrosion resistance to simulated exhaust gas of Fe-28Al-5Cr, Fe-28Al-5Cr-0.5Nb-0.1C and GTA (gas tungsten arc) welded Fe3Al based alloys has been investigated. The composition and emerging mechanism of corrosion scale have been analyzed, and compared with former materials used in the exhaust manifold system such as low carbon steel A3 and 1Cr18Ni9 stainless. The results indicates that Fe3Al based alloys and its weldment exhibited corrosion resistance to the test environment as good as stainless because of the producing of continuous and dense Al2O3 surface scale, by contrast, the oxide of A3 steel was loose and discontinuous Fe2O3 scale which was easy to be peeled off and led corrosion accelerated.
Abstract: The function of Ca3N2 on the reaction between B4C and NH4Cl was investigated.Under normal pressure and high temperature. The results showed that there was small amount of hBN formed in the reaction at 950℃, and little change took place after Ca3N2 was added. The amount of hBN achieved from the reaction at 1200℃ was more than that at 950℃, and much more hBN was gained after adding Ca3N2. It was concluded that Ca3N2 performed catalytic function in the formation of hBN. In addition, the results also indicated that the catalytic function of Ca3N2 was less ho that of Li3N, and they could only act as catalyst at melting state.
Abstract: Based on floe-varying characteristics of thixotropic casting semisolid alloys, the flowing state of the semisolid alloy and the procedures as filling up the mould by means of thixotropic casting being performed, is simplified to the flow which features in an equal temperature layers, audit also is simulated and verified. The analogical results corresponds to that of filling up mould.
Abstract: The wear resistance of TIC-Fe cermet coating prepaid by reactive flame spray of ferrotitanimu, graphic and iron powders was sutdied. It was revealed that the microhardness of TiC-rich and TiC-poor layer within the TiC-Fe composite coatings is 11.9-13.7 GPa and 3.3-6.0 GPa, respectively. A dry wear test showed that their wear resistance is five times higher than WC-Ni45 cermet coatings obtained by traditional process. The major wear mechanisms are surface adhesion and a little stripping of TiC.
Abstract: The Ni81Fe19/Ta films with different Nine thicknesses were.prepared at different base pressures and sputtering pressures. The results of magnetic measurement and atomic force microscope (AFM)showed that the thicker films and the films prepared at the higher base vacuum and the lower sputtering pressure had the larger △R/R. The reason is that the higher base vacuum and the lower sputtering pressure introduce the larger grain-size and the lower surface roughness, which will weaken the scattering of the electrons, reduce the resistance R, and increase the △R/R.In the thicker films, the effect of the larger gum-she will offset that of the larger surface roughness, and the △R/R can be increased.
Abstract: A new device that is used to produce ceramic lined steel elbow by SHS-gravitational process has been developed. The device composes of three parts:main port, control part and watch part. There are motor, decelerating case, mounting plate and base in the main part, temperature detector, rate adjuster and computer in the control part, and composes of monitor and camera in the watch part. The device can auto-control the synthesizing process of the composite elbow. The composite elbow with the diameter of 325 mm and the curve angle of 90° is produced.
Abstract: TEM and HREM observations of the MoSi2-SiC composite synthesised in situ reveal that large amounts of dislocations exist in the MoSi2 matrix specially near the interfaces between MoSi2 math and the SiC particles, and the SiC particles typically contain defects including twins and stacking faults. Nanoindentation investigation shows that there exists a gradient distribution of microhardness near the interface of MoSi2/SiC. The microstructurd characters above can be attributed to the residue heat stress due to the CTE discrepancy between MoSi2/SiC generated in the cooling process of the production.
Abstract: Al2O3/Al-Cu and Al2O3/Al-Cu-Si composites are fabricated from in-situ reaction Al+CuO and Al+CuO+SiO2 respectively. SEM observation of the morphologies of the materials, XRD analysis of the phases, and EDS analysis of elements in the phases are performed. Primilinary results show that alloy elements Cu and Si are presented as predicted, as well as fine and homogeneously distributed Al2O3 particles formed, which indicate that the newly developed concept is feasible.
Abstract: A near dense graded SiC/Cu plasma facing material with a spectrum of 0-100% compositional distributions of SiC was successfully prepared by a new process termed graded sintering under ultra-high pressure. Tests on plasma relevant performances showed that the chemical sputtering CD4 yield of SiC/Cu graded composite is 80% lower than that of SMF-800 nuclear graphite, while its thermal desorption is about 10% of that graphite; Fatigue cracks and chemical decomposition were found on the surface of SiC/Cu FGM after 300 cycles of thermal impact with a power of 398 MW/m2 laser impulse, slight damage was also observed on the material surface after in-situ plasma trradiation in Tokamak apparatus.
Abstract: Magnetic field treatment can effect transformation process from austenite to ferrite of microalloyed steel,especially, in the nucleation ratio and growing rate of ferrite.Magnetic field treatment can increase nucleation ratio of ferrite, meanwhile, the growing rate is enhanced. The transformation period is decreased due to the function of magnetic field, and the refine grains present finally.
Abstract: A micro-crystalline MA956 ODS alloy coating of about 50mm thick was developed on the 1Cr18Ni9Ti stainless steel by means of a high-frequency electro-spark deposition technique. The coating has a very fine grain size of about 100 nm and excellent metallurgical bonding with the substrate. Isothermal oxidation in air at 1000℃ for 100 h shows that the micro-crystalline MA956 ODS alloy coating on 1Cr18Ni9Ti promoted the selective oxidation of Cr and also improved the scale spallation resistance dramatically, thus increased the oxidation resistance of 1Cr18Ni9Ti greatly.
Abstract: The oxygen self-diffusion paramaters in strontium titanate were assessed. The results indicated that:(1) Oxygen diffusion occurs through a vacancy mechanism in strontium titanate crystals. The ranking of the ions based on the magnitude of diffusion coefficients is oxygen strontium and titanium ion. (2) In the temperature range from 1098 to 1623 K, under an oxygen partial pressure in the range from 0.2×104 to 7.6 ×104 Pa, the temperature dependence of the oxygen diffusion coefficient in strontium titanate is obtained. The diffusivity of the oxygen diffusion in strontium titanate is insensitive to the variation of oxygen panal pressure and the dislocation density.
Abstract: The composition design idea of IF steel is eliminating the atoms of C and N dissolved in steels. On the basis of the thermodynamics analysis and the TEM observation of extraction precipitates, it is shown that sulphur can act as a positive role to fix the interstitial carbon atoms due to the exist of Ti4C2S2. If a proper ratio of sulphur and carbon in Ti-added IF steel is kept, the favorable precipitate will be product.
Abstract: On the basis of a large amount of data measured. the problem of rolling by plate width increase in sequence (RPWIS) for 2800 four-high mill, is analyzed. By means of the program of two-dimensional finite element method with varying thickness, the simulative model in the roll deformation or crown forecast for 2800 four-high mill is specially established. In terms of the results of simulative calculation, the influence of work roll wear contour (which appearing in a later period of work roll rolling, like basin's shape), plate width or roll force to plate crown is revealed and the effective method is pot forward to prevent RPWIS.
Abstract: The graphic programming system of NC spinning machine under Windows with Microsoft Visual C++ programming language, which appropriates for IPC, is described. This system has a good graphics-user interface. By which all kinds of mold and roller path graphics that processed in spinning were drawn.According to these graphics, the system automatically works out data file.
Abstract: The aim of sign language recognition research is to let the computer to understand what a deaf 'said' using the sign language so that the computer can output the recognition results in the form of text and/or speaking language and help us to communicate with the deaf. The characteristics of Chinese Sign Language (CSL) are analyzed in the view of sign language recognition. The analysis and comparison of the two existing sign language recognition methods, the machine-vision-based method and the body-instrumentation-based method, are also done and a new clarification method for the CSL is also proposed.
Abstract: Analysis on security of a secure speech communication system based on digital chaos is given, which is attacked through regression maps and phase space reconstructing and so on. Experimental and simulative results turn out the security of communication systems based on digital chaos is better than that based on continuous flow chaos. In the end, time-sharing maps and contemporary multi-maps mised and piecewise nonlinear maps are presented to enhancing security.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
