Abstract: A theoretical study of the lognormal distribution and the three-parameters lognormal distribution are presented. The emphasis is on the study of lognormal kriging. The lognormal kriging systems and logarithmic kriging variance are established after non-bias condition and minimum estimation variance are studied. The kriging weights λα are solutions to the kriging systems. The kriging estimator Zv of each block of a deposit can be estimated. Kriging estimator is the unbiased linear estimator with minimum estimation variance. The method is illustrated application to ore reserve estimation of a iron-copper deposit.
Abstract: The influence of temperature, reductant, a combination of reductant and the size of chromium ore, as well as the other facts on the characteristic of direct-reduction of chromium ore were studied. Adding agents were experimented in order to increase the reaction of chromium ore reduction. Based on the theory of solid-solid reaction via the medium of gas, the reduction process was discussed. The experimental results can be used as the theorical guide to pioneer the smelting-reduction of chromium ore containing carbon in shaft furnace.
Abstract: In this work, based on theory of the turbulent jet and the turbulent boundary layers, the turbulent fluctuation properties in the mixing section of the round injector have been researched. From Reynolds equations the basic equations and the momentum integrating equation of turbulent flow field to cylindrical coordinates in the round injector have been presented. The approach of designing the optimal injector has been developed, and the formula of the optimal designing of the injector have been put forward.
Abstract: Based on the fluidized bed divided into three areas, the exchanges of gas and solid between the both areas of fluidized bed were studied through a cold model. Experiments showed that it is feasible to reform three areas in fluidized bed to both areas, which is helpful to operating and decreasing the investment of fluidized bed. If fluidization index is properly raised, the heat exchange between combustion and gasification areas will meet the needs of operating, and the heat value of gas will also increase. A vertical device in fluidized bed will help to increase the heat value of gas.
Abstract: The Influences of subcritical annealing on the austenite transformation kinetics in the intercritical annealing of Fe-C-Mn dual phase steels are studied by means of OM, SEM. And using EDX, WDS technology, Mn-partitioning in carbide during subcritical annealing are measured. The results show that subcritical annealing is believed to prompt the Mn-partitioning to carbide, and to form a Mn-rich austenite during the intercritical annealing. Therefore, the hardenability of austenite is increased during batch annealing. It should be applicable for batch annealing processing of dual phase steels.
Abstract: Experiments have been made on microalloyed medium-carbon L45 steel under the condition of controlled rolling and controlled cooling. The various mechanical properties and volume fraction of pre-eutectoid ferrite fa, size of ferrite da, free distance of ferrite λα and and the interlamellar spacing of pearlite S0 have measured. By using multiple regressive analyses to research, as a result, the mathematical expressions of relation between the various mechanical properties and structural parameters of the controlled rolled and controlled cooled microalloyed medium-carbon steels have been obtained. According to the informations provided by these mathematical expressions, into the Strenthen-toughening mechanizm of the controlled rolled and controlled cooled microalloyed mediumcarbon steels have discussed.
Abstract: This paper has made an analysis in both theory and practice, on the improvement of old double-duo mills which are using in our country. It is considered that the replacement of the old double-duo mills by double-duo short-stress path mills of GYF type is a suitable way for the condition of China, and the backward of our wire rod production can put forward.
Abstract: In the paper, the elastoplastic boundary element method (BEM)of the initial strain is worked at calculating parameters of flat rolling of plate and strip. The calculating results obtained in studying on flat rolling of plate and strip coincide with the experimental data. The research shows that the elastoplastic BEM is satisfactory for analyzing flat rolling of plate and strip.
Abstract: By means of the boundary conditions of the crack, a system of singular integral equations is obtained. Using the numerical method for the solution of the singular integral equations, the stress intensity factors at the tip of a branched crack in the gear surface loaded by Hertzian contact stresses can be calculated. From the current theories about a crack propagation, the tip of the branched crack spreads to the surface in the direction of about to 60° with the declined crack.
Some incorrectness of field orientation system made by motorparameter and speed detecting errors are presented in vcctor control system. The robustness of a field-forward vector control system is studied. A new adaptive correction strategy used PRBS on-line identification technique is proposed. This method is simnle and doesn't need extra sensors.
Abstract: For the binary phase diagram involving two phase layers, the layer curve can be individed into two parts lα and lβ from the critical point. General relationships between the binary phase diagram and the thermodynamic properties of the phases have been given in this paper. It is shown that a knowledge of any four of the following six quantites is sufficient to permit the other two to be calculated exactly:the layers curve lα and lβ, enthalpy of the a phase, entropy of the a phase, enthalpy of the β phase, entropy of the β phase. Consequently, some very useful formulas, such as the formulas for calculating activities from phase diagram can be dirven.
Abstract: The technical parameters of the chemical colouring for stainlesssteel have been obtained. The pattern of the changes of solution composition and pH in colouring process have been found out. The addition of the selected additives imporved the quality of colouring film and technical conditions. It was distinguished tentatively that the colouring film of stainless steel was a semiconductor film. After colouring and hardening, the corrsiotl resistance of stainless steel was improved.
Abstract: The experimental results for liquid-liquid extraction show that the content of RE2O3 in last enriched solution can reach 130g/l or so. This solution is evaporated to produce the solid crystal of mischmctal chloride. The experimental conditions are as follows:extractant is D2EHPA (70%), there is 3g/1 of RE2O3 in leaching solution, and the counter solution is 5N HCI.
Abstract: After carbonization, the high melting pitch-base carbon fibers are activated in CO2 atmosphere at certain temperatures. The activated fibers have good adsorbent function and regenerative behaviour.
Abstract: The optimum conditions for the co-coloration effect of theco-colored heteropolynuclear coordination compounds in the system of "Alkaline earths(Ⅱ)-Rare earths(Ⅲ).Alizarin violet-Tetradecylpy ridinium chloride" are reported. By analysis of the experimental results, it comes to the following conclusions; the radius of ion or ratios of radii, but not the hyclrolytic properties of the metal ions, play an important role in the co-coloralion of the heteropolynuclear coordination compounds. There is a possibility to search for a new co-coloration system, though different system has different optimum ratio of the radii.
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
