Abstract: An engineering prediction method is presented for evaluating trends of the displacements based on displacement histories obtained from underground excava tions.On this basis the distribution of the pressures, stresses and safety degree of underground excavations can be determined by using numerical methods. Therefore, the proposed method will find a wind application in safety control, support design,construction assessment of geotechnical engineering projects.
Abstract: The cusp catastrophe model of coal outburet in mining is set up according to the catastrophe theory.The engineering phenomena of the progressive and bursting failures near free surface of coal or rock seam are described by the model.
Abstract: The some information of coal outbursts or rockbursts must be contained in microseismicity before coal outburet or rockburst in mining. In the paper, the feature of time fractal dimension of microseismicity before coal outburst or rockburst in mining is studied by using fractal geometry.It is shown that the time fractal dimension of microseismicity information before coal outburot or rockburst may be used as one of indexes of predicting coal outburst or rockburst.
Abstract: The effect of bench height on open pit mining is studied.The rational bench height is proposed on the principle of that the comprehensive present value of transportation cost, maitaining and building transportation road cost and maintaining final wall bench cost is minimum.
Abstract: A fire test is designed in a experimental roadway during 218min, which is 5.4m2 in section and 70m in long, the fire process and the temperature of below the fire area are studied. There are three stages in the case of without no extinguishing:oping stage, stable stage and failing stage.
Abstract: The fume temperature distribution below the fire area in the section of the roadway, and the changes of the fume temperature in each sectiom are studied.The achievements show that fume temperature distribution is not even in section,it is higher near the roof of drift, and is lower at the foot and the side walls;as the distance to the fire area increases, the difference of fume temperatures of various measuring points in the section increases, when the average or the highest temperature is the same.
Abstract: Based on analysis of rock deformation curves around underground opening,the characteristic value method is proposed. The application of this method in determining the optimal supporting time and in classification of deformation pattern is described.This method is reliable, simple and convenient confirmed by a case.
Abstract: This paper has introduced a diagnostic parameter choosing method for a multiple-input and multiple-output system. This method uses the entropy of the visible diagnostic parameter set as the criterion to classify the heuristic diagnostic parameter set,and on basis of the subset which is decided by the system's current state,forward reasoning is carried out to get a fault subset, regarding which being the object,backward reasoning is used to decide the final fault set. The element's correspendent measurable diagnostic parameters in the final fault set are the desired system's diagnostic parameters. This method can be a part of a diagnostic expert system.
Abstract: The hot tearing criteria presented up to now have been comprehensively analysed in the paper. Based on the experimental results and the analysis through the mechanical strength theories, the unreasonable aspect of the customary strain theory of hot tearing is revealed. It is pointed out that the hot tearing is a kind of plastic fracture in essential. The hot tearing potential is defined, and the solidification mechanics criterion is put forward consequently.
Abstract: The engineering importance to study the mechanical properties of alloys during solidification is pointed out. Based on the experimental results and the rheologic models obtained by the authers recently, the constitutive equations and the creep, relaxation properties are revealed.
Abstract: The mechanical alloying of Ti50Al50 in N2 was investigated.After milled 30h, the elemental powder mixtures transformed into complete amorphous phase, nanocomposites of γ-TiAl+Ti2AlN could be insitu obtained after proper annealing treatment.
Abstract: The metal films have been discovered on synthesised cBN surface. The morphologies of metal film have been shown.The composition of the metal film which consist of Fe, Ni, Mn, Mg, has been confirmed. The functions of the metal films have been analysed, and the formation mechanism of the metal film has been put out.
Abstract: A reasonable dynamic model of the axial vibration for 4-H strip mills is established in this paper. And with the predisplacement theory in tribophysics,the definition of axial rigidity is given. The axial nature character is obtained. The analysis of the dynamic load amplification factor provides basis for reasonable discussing the effect of the axial force on roll bearings.
Abstract: Based on the theoretical analyses, 4-H hot strip mill and 4-H cold strip mill have been tested. The force, power and dynamic characteristics of the roll systems are obtained in this paper.
Abstract: Based on the analysis of the process of cross wedge rolling,the geometry model of rolled part and tool has been established. The contact surface of rolled part with tool has been studied. The contact surface equations and the boundary curve equations have been presented. The software package of a computer aided drafting of the part during rolled has been developed. The contact surface has been displayed in images.
Abstract: Two fuzzy flatness defect pattern recognition methods are developed according to the fuzzy classification principle, and tested by datas measured from industry. A good conclusion is achieved.
Abstract: A clear defect in Elliott's scheme is that the more parameters estimation are required than those actually needed. That is harmful to the converge of estimated parameters. This article presents a direct adaptive pole placement control scheme using general integral action, the degree of estimator can be reduced and the effect of deterministic disturbances can be removed in this way. No static track control errors for reference input signals could be achieved.
Abstract: The solid phase reaction between iron and hematite have been investigated by using the diffusion couple method. The results show that the product phase between iron and hematite was formed on the layer of hematite principally, but the morphology was aggregate arrangement, which is different from that of the oxidation in air, and the final product was the wustite from the hematite at Fe saturation.
Abstract: A semi-empirical formula for energy gap calculation is obtained from the Lorentz electron theory of solids. The calculated results of energy gap on alkaline earth mixed halides are reasonable. The classical bond ionicity is corrected from the consideration of both the electronegativity difference and bond distance. It is revealed that the corrected ionicity is more suitable to characterize the chenmical bonds.
Abstract: The effect of hydrogen on the irradiation behaviour of oxide dispersion strengthened(ODS) ferritic steel was studied by means of ion bombarding at room temperature and irradiation in HVEM at room temperature and 500℃,respectively. Microstructure of ODS ferritic steel did not change at room temperature after hydrogen-ion bombarding. Observable voids were not formed during in-situ electron irradiation at 500℃ for the specimen bombarded with hydrogen. The electron irradiation experiments at room temperature for the specimens with and without hydrogen-ion bombarding, respectively, were performed. The results indicated that hydrogen played an important role in the motion and collection of point defect.
Abstract: The tribological behavior of sulfurized olefin(SO) and tricresyl phosphate(TCP) on Ni-P brush plating layer was studied systematically on a ball-on-disc testing machine, and that of SO and TCP on 1045 steel was also studied for comparing.The composition of lubricating films on disc wear surfaces was analysed using X ray photoelectron spectroscopy and Auger electron spectroscopy methods. The lubricating mechanism of SO and TCP on Ni-P brush plating layer was discussed.It was found that the lubricating oil containing SO exhibited very good lubricating behavior on Ni-P brush plating layer. But the addition of TCP in lubricating oil showed adverse effects.
Abstract: The synergistic effects between three kinds of chemical heat treatment surfaces of 1045 steel,including oxy-nitrided, nitrided and sulfurized surfaces,and two kinds of extreme pressure (EP)-antiwear(AW) additives, sulfurized olefin and tricresyl phosphate, were studied systematically on a ball-on-disc testing machine. The composition of lubricating films on disc wear surfaces was analysed using X-ray photoelectron spectroscopy and Auger electron spectroscopy methods.The mechanism of the synegistic effects was discussed. It was found that exeellent synergistic effects on increasing load carrying capacity and reducing friction and wear could be obtained.
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
