Abstract: The difference in meaning between rock material failure and rock project failure while losing its stability is distinguished. Based on the idea, it is incorrect that rock falure criterion and rock project failure are conisdered identical in numencal calculation for underground project and in-situ project design.Simultaneously, with the aid of system energy principle and catastrophe theory, the criterion of energy catastrophe for rock project system failure is put forward and used in the calculation of the finite element method (FEM) to judge the probability of rock project system failure.Proved by the real project, the ideas and criterion are correct and of certain value, the results of calculation coincide with the state of the mining proJect.
Abstract: The mathematical model of air temperature and relative humidity in the inclined shaft are determined on the basis of the heat transfer theoretics.The varing law of the air temperature and relative humidity in the inclined shaft with the distance from the air inlet and air velocity are analyzed at the existing condition of the east inclined shaft of Dagu Shan iron mine. And the methods of solving the humid-foggy air are presented.
Abstract: The experiments have been carried out to carefully investigate precipitation of cemenhte from pure iron during rapid cooling. By TEM, it was observed that the cemenhte, also called as the thini cemenhte, precipitated on the grain boundray from supersoluable alpha ferrite, and its shape, which is usually spheroidal or filmy, depends on the carbon content of the pure iron.
Abstract: The experiments using synthetic desulphurizer with Aluminum slag ash to increase the efficiency of desulphurization and shorten the LF process time were described.The efficiency of mis desulphurizer and factors influencing its effects were emphatically analysed. The gists of the experiments process were as follows: the optimum control of top slag composition, forming the top slag in ladle eariy, the good deoxidation,increasing the Ar gas shtring strength. The experimental results showed that given the desulphurizers addition among 15~20 kg/t, the average LF process time is shorted 10 min, the average desulpherizing rate is raised 16%.
Abstract: Crack growth rate of superalloy turbne disks is tested by means of direct current-voltage.The results show that the CGR of superalloy turbine disks is decided by stress rupture duchlity, not by strength of superalloy and the valuahon of CGR is determinned by the incline of curve and the range of stress strength factor.
Abstract: Recrystalization of the dispersion strengthened fetrihc steels, which was manufacted through chemical socking, was systemahcally studied. It was found that the recrystaization temperatures varied from 750 to 780 ℃, fine grains could be obtained by annealing after high-level deformation, grain boundaries of the grains with size smaller than limited value could be effectively Pinned by dispersoids, and Y2Ti2O7 was stable during deformation and annealing.
Abstract: A low frequency oscillation is overlapped in strip drawing test, which simulates the friction. state of sheet between blank holder and die with oscillation. The influence of amplitude, frequency, drawing speed, normal pressure, surface topography on friction have been given through the test It shows, overlapping low frequency oscillation on blank holder in sheet metal forming is helpful under some conditions.
Abstract: The composition and structure of passive film formed from CrO3-H3PO4SiO2, systems on galvanized steel sheet were inveshgated, the corrosion resistance and its protective causes of the film were also discussed. The experimental results showed thatthe film is a thick type of complex conversion coating with gelatinous net structure containing CrO3, Cr(OH)3, CrOOH, ZnCrO4, ZnSiO3, Zn3(PO3)2, CrPO4 and SiO2, etc. The white rust-resisting property of the film is of three times better than that of film formed from CrO3-SiO2, systems because of good shielding and inhibiting.
Abstract: The [Ni80 Fe20 /Cu]N multilayers with low saturation field and giant magnetoresistance effect have been successfully prepared by magnetron sputtering method.The oscillatory changes of its magnetoresistance and interlayer exchange coupling with copper thickness increasing have been observed at room temperature while saturation magnetoresistance values reach 19.4% and 11.7% and saturation fields are approximately 64000 A/m and 8 000 A/m when the Cu layer thickness equals 1 and 2.2 nm respectively.Saturation magnetoresistance values are 33.2% and 27.6% at low temperature(77K).Dependence of giant magnetoresistance on microstructure, including NiFe layer thickness and then number of period N, has been studied systematically. Changes in GMR characteristics have been observed after vacuum annealing.
Abstract: The influences of temperature, pressure and the elevating pressure speed on the amber cBN synthesis using catalyst have been studied.The resultS show that, under the experimental conditions, both temperature and pressure for the amber cBN synthesis are belower than these for the diamond synthesis, and the results of cBN synthesis can be improved if the elevating pressure speed is slowed down.
Abstract: Mechanical properties of domestic and overseas (T300) PAN-based carbon fibers are measured. Chemical composition, crystallite size parameter,surface and fracture texture of both carbon fibers are studied by chemical analysis, SEM observation and X-ray. The fracture texture characteristic graph of both T300 and domestic carbon fibers are presented. On the basis, effects of the fibers structure on the carbon fibers properties and relationship between the carbon fibers structure and thier properties are analysized.
Abstract: The effect of roll Press strengthening on the fatigue fracture of bolts which made of 30CrMnSiNi2A steel was studied. The experimental result shows that the endurance limit of the bolts is increased about 58.6% by roll press strengthening, the fatigue fracture appearane is changed, the number of the origin region of the fatigue crack is reduced, the area of the crack growth zone is increased, and the width of the fatigue striahon is decreased. Finely, the mechanism of roll press strengthening was discussed.
Abstract: Lead magnesium niobate ceramics have been synthesised by wet chemical method and their microstructures are studied by means of X-ray diffraction(XRD,scanning electron microscopy(SEM) and transndssion electron microscopy(TEM). The experimental results show that pure perovskite PMN ceramics is obtained during calcining at 800℃ for 1h. The grain size of PMN ceramic varies from 150nm to 200nm after sintering at 85O~ 920 ℃. The pyrochlore phase is situated at the grain boundaries of the perovskite phase if it occurs. Excess PbO phase existing in the ceramic is in favour of sintering of the cerarnic powder.
Abstract: A new method of signal filtering with wavelet packets and signal reconstruction is proposed.At first, signal is decomposed in different frequency bands, and then the signal of each frequency band is reconstructed. By analyzing the vibration signal of a motor, this method is applied in signal filtering successfully.
Abstract: Finite Element Method (FEW is applied to research and analyse the distribution of stresses in a sample casing under uniform external pressure, which has various initial geometric imperfections (ovality and eccentricity).
Abstract: Bond graph model and equation of state for the hydraulic speed regulation system are founded under the method of bond graph. Compared with real transit process response curver of the system obtained by computer aid test, the result of dynamic simulation of the system is relatively same after some experiments.
Abstract: The relahonship between hobbing force and vibration, and the effect of paramertes and cutting methods on the hobbing force have been studied.The results show that the alternative action of hobbing force resuls in the forced vibration in bobbing process, the characteristic of hobbingg is the cause of the self- exited vibration condition.By selected cutting tools, cutting parameters and cutting methods reasonably can prevent the self-exited vibrahon and avod resonance and forced vibration.
Abstract: A modular design method to recognize the operahng mode in process of complex production is provided. The enhre recognihon task is divided into two sub-modules; modeling module, trained off-line, and decision module, Performed on-line.In modeling module, the adaphve time-delay neura network is used to construct various predicting models which correspond to different operating modes. In decision module, for a new sequence, which operating mode it belong to is deduced depending on matching degree between this new sequence and all predichng models. The simulation results show the effectiveness of the method.
Abstract: Generalized sell automaton that on synthesized deal with random indetermi-nacy and fuzzy indetermiacy and corresponding generlize inductive logic caustl model are advanced in this paper, which is based in sell automaton(belongs to inductive abdility logic scope) which is constructed by A. W. Burks and describes worid. And soluhon to the problem that isn't solved in the inihal model about main element deter-mination and causal disturbance correspondence is also given in the paper At the same hme the new automatons application in intelligence control is posed.
Abstract: The necessity and Possibility of the design of the domam intelligent DSS generator are given. A kind of conceptual architecture of the domain intelligent DSS generater and its design method are proposed.
Abstract: A robust internal model control algorithm, which can be used in open-loop unstable systems, is presented, with its robustness and global convergence is proved. The simulation example demonstrate the effectivness of the algorithm proposed.
Abstract: A method for dishngushing the root of an equation of degree 3 over finite field GF(3m) is suggested and the state of root of equation of degree 3pl overfinite field GF(pm)(p≥3) is discussed. The method for distingushing the roots of degree p and pl+1 over GF(pm) is also discussed.
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
