Abstract: Summarize and analyse a number of the experimental and theoretical results on glass, ceramics and rock fracture under static and dynamic indentations, describe in detail the fracture patten and process of rock under static and dynamic loads; introduce the relations between the length of the radial (median) and lateral cracks and indentation loads, and discuss the relation between the length of the radial crack ard impact speed of indenter. Finally, some applications of the research results to the design of drilling machinery and the measurement of few mechanic parameters of rock are suggested.
Abstract: Using the pellet containing carbon, the Fc-alloy in that the chromium content is 18% has been produced in a shaft furnace. The furnace capatity was 0.10m3. The distributions and the reduction reaction of chromium, sillicon and sulfur etc have been studied based on the former theoretical resuts.
Abstract: This paper studies on the coupled reaction of coke gasification-iron ore reduction in majors of iron and steel corporation in China, simulating the behaviour of blast furnace dependenting on gas composition and gas temperature. It was found that the reaction charateristics of the coke gasification-iron ore reduction were markly affected by its history. The efficiency of blast furnace should consider the imbalance between CO produced by coke gasification and CO consumed by iron ore reduction.
Abstract: Initial and final oxygen potential in simultaneous dephosphori-zation and desulfurization pretreatment with injection of CaO-based fluxes were measured by using of the oxygen sensors of ZrO2·MgO solid electrolyte in our laboratory and the thermodynamic analysis were considered. The results shown that:(1) initial oxygen potential is Po2=10-8.45~10-9.7 Pa (10-13.46~10-14.76 atm) which is 10~103 times as high as the oxygen potential calculated from the C/O or Si/O equilibrium reaction. (2) final oxygen potential is Po2=10-7~10-9 Pa (10-12~10-14 atm) which is 10~103 times as high as the initial oxygen potenlip.l and is in good agreement with the optimum oxygen potential in the thermodynamic calculation (Po2=10-7.88 Pa (10-12.88 atm). And (3) dcphosphorization ratio increases, final phosphorus content decreases, and dcsulfurization ratio decreases slightly, final sulfur content increases slightly with increasing of oxygen potential in hot metal. In addition, optimum oxygen-electrode potential range were analyzed in electrochemistry, and the reaction mechanism of simultaneous dephosphorization and desulfurization in injection pretroatmcnt within hot metal ladle was also discussed.
Abstract: In this work, a mathematical model has been developed by means of theoretical analysis for the oxygen top-bottom combined blowing process, in which a gas-stirred is injected through the tuyere at the center of the vessel bottom, in a hot model with 100 kg capacity. By use of this model, the changes of temperature and compositions of metal bath can be estimated. The results calculated by the model have been in good agreement with the experimental data obtained in hot model experiments.
Abstract: The austenite grain growth tests for six heats of micro-alloyed high nitrogen L45 steels were experimented at the condition of long time heating (1800s) and stort time heating (5s) by rapid heating rate (50℃/s).The mean intercepts of austenite grains were measured. Utilizing the transmitted electron microscopic photoplates for extsacted replica the size distribution of the precipitated phases in steel 1#, 3# add 6# were determined. The chemical composition of the fine precipitates was analysed by Energy Dispersion Spectrometer attached to the TEM. The mechanism of the effects of Al and the microalloyed elements Ti, V. Nh and of heating temperature on the austenite grain size was studied.
Abstract: The relationships between Yickers hardness (H) and Temperature (T) for six industry alloying tool steels and seven WC-Co sintered alloys have been investigated. When T is lower than tempered, the reversible softening value for tool steels undergone quenchingtempering secondary hardening treatment is a linear function of T. The diferences among reversible softening factors for various high speed steels (HSS) are very small. Hence, a simple relation to estimate the hardness of HSS at T below 500℃ is presented. When T is higher than tempered, the H-T relation of tool steels is complicated, but H is still mainly determined by the room temperature hardness after heat treatment. For WC-Co sintered alloys, the H-T relation is linear up to 800℃, and the relation between H and cobalt content (Co%) is also linear when Co<20%. The relation tor estimating hardness of WC-Co alloys from T (<800℃) and Co (3%-20%) is presented.
Abstract: The partial isothermal sections of phase diagram at 750℃ and 900℃ in FeNiCr-W-Mo system have been determined by X-ray and TEM methods. Experimental results show, that when the content of Mo% is higher than 1.5% and 1.0% the μ phase can be formed at 750℃ and 900℃ respectively. When the content of tungsten is higher than 7% the μ and Laves phase can be formed at 900℃ in the chemical composition regime of tested alloys, however the Laves phase can not be formed at 750℃ regardless of the total amount of tungsten and molybdenum. In addition, experimental results have also proved that the traditional electron vacanr number Nv=2.30 for μ phase formation can not be vised in the investigated system.
Abstract: Based on the theory of control and time scries, a new dynamic way to compensate the short-period error of the gear hobbing machine is put forward. It is suited for application in production. The control system of compensation is also built up. The feasibility and effectiveness of this way is analyzed with the experiment and simulation test in computer.
Abstract: The paper discusses the strategy of reducing the harmonic currents of the inverter on the base of improving the power factor of conventional static scherbius drives. Not only the harmonic currents of inverter has been suppressed, but also the power factor of inverter has been improved with the aid of subharmonic PWM techniques for deter-mining optimal switching angles and making firing angle α vary between 180° and 270° using GTO thyristor instead of normal thyristor in inverter. The scherbius drive experiments employing the new inverter show that the power factor of leading current type is much higher than lagging current type and the lower order harmonic currents of the inverter have been grertly reduced. The structure and the control of the equipment is very simple.
Abstract: The distribution of α component will change with the diffusion of β component in a M-α-β ternary system, as the result of the interactions between the two components. The diffusion equation of such process for α component has been set up, and the solutions under two specified conditions,the "ihitial stage" and "equilibrium stage", have been obtained.
Abstract: The effective channel for improved die life is chemical vapor deposition (CVD) coatings of Ti (C, N) and TiN. This report summarises the service conditions of some coating coated dies in application to industry. The mechanism of improved die life is also studied.
Abstract: The mathematical models of heat transfer in the chamber of furnace and the mathematical model during metal heating in four-section continuous furnace are set up, The rurnace gas temperature, furnace wall temperature, metal temperature and heat flow density on metal surface are calculated. On the basis of mathematical model, by the method of elicited optimization and optima-lity criterion, the oplimized parameters are calculaled, The results are practicable and suitable to the real lurnacc.
Abstract: On the basis of same heat flow between hot surface and col surface, the concept of effective thermal conductivity is adapted to solve thos problems which have combined convection and conduction in enclosure. The relations of effective thermal conductivity with the shape of cylindrical enclosure Re number and Gr number arc calculated, and all the results are explained physically. Those results are available to solving the problems such as metal solidification and crystal crystallization etc. The comparison is made between the calculating results and experimental data of GaAs crystal growth, and it is founc that they are agreement.
Abstract: The bright FeNiP alloy film can be electroplated with using the ascorbic acid as the complex compound. Selecting suitable bath solution, the compo sition of alloy film is depended on the technological condition of pH, temperature and cathodic current density.
Abstract: Kim B.Bruce gave a system of axioms for second order logic L(Q).H.J.Keisler in 1977 published a book called 《Model Theory for Infinitary Logic》 to give a system of axioms for infinitary logic. This article combines the two ideas of the two systems of axioms, applying the consistency property introduced by the book 《Model Theory for Infinitary Logic》 to give a system of axioms and model theory for infinitary second order logic Lw1w(Q). This part of the article is mainly the proofs of omitting type theorem for Lw1w(Q) and prime model theorem for Lw1w(Q).
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
