Abstract: The Baiyinnuo'er lead-zinc deposit is the largest lead-zinc deposit in the north part of the Changjiang river in China. Ore bodies are obviously controlled by strata lithology and fold structure deformation in this deposit. Generally, the fold axis bends down to SW direction, with an angle about 25°, and its trend is along NE direction, but the fold shape in the south ore belt is slightly different to that in the north ore belt. Based on characteristics of tectonic-controlling mineralization, the 2nd ore body's extend was pursued to depth situation at the high coverage fraction area in the south part of 29 line with an EH4 conductivity image system. The result shows that the studied area is a new mineralization belt. The electricity nature difference of the geologic body underground based on EH4 anomaly can be exactly explained according to the known characteristics of tectonic-controlling mineralization. Therefore, the 2nd ore body still extends to depth in the south part of 29 line.
Abstract: Based on experimental data from a drilling process monitoring system instrumented with a hydraulic rotary drill rig in fill-weathered granite formation, the diamond penetrating energy was analyzed. The result shows that the distribution of the penetrating energy in fill-weathered granite formation agrees with that in common weathered granite formation. A negative correlation between the viscous energy, kinetic energy, total penetrating energy and the weathered degree of granite existed, and a positive correlation between the thrust force energy and the weathered degree was presented, which indicates that there is a well response between the penetrating energy and the weathered degree of rock. However, the kinetic energy, thrust force energy and viscous energy are limited in identification of formation because of different effects in various drilling modes. The specific energy of diamond drilling (SEDD) increased with the weathered degree of rock and the values of SEDD can be classified into corresponding range according to the weathered degree of rock. It is shown that the SEDD in rotary drilling is apparently less than the specific energy of percussive drilling (SEPD) in both fill soil and very strongly weathered granite formation. Reversely, the SEDD is much more than the SEPD in lightly weathered hard rock.
Abstract: A new discriminant analysis method was brought forward to solve problems such as the complexity of slope stability factors and the hugeness of computation workload by the traditional slope stability analysis method. Six indicators that are widely used in slope stability analysis, which included slope gravity, cohesion force, friction angle, slope angle, slope height and pore pressure ratio, were used as discriminant factors to establish a discriminant analysis model for slope stability forecast. The analysis result of typical project examples shows that this method is simple and feasible, and has stronger analysis reliability. It can eliminate the influence of human factor in discrimination and classification of slope stability and can be used in practical engineering.
Abstract: The model test in combination with the non-target digital photography deformation measure technology was carried out to study the bearing capacity, soil-pressure distribution, reinforcement mechanism and deformation pattern of vertical reinforced foundation. The results shows that the length of vertical reinforcement and the distance of vertical reinforcement to foundation have obvious influence on the bearing capacity and soil-pressure distribution, the main mechanism of vertical reinforcement is confinement and obstruction, and the deformation pattern is dependent on the location and length of vertical reinforcement.
Abstract: Acid red 12#, a long chain multi-benzene ring coloring dye, was used as the representative compound to decide the adsorption isotherm formula of it in a mesoporous material and the relationship between the equilibrium closing rate and time by effective diffusion coefficient testing. Based on the theory of similar rate equations between unsteady diffusion mass transfer and heat conduction, the effective diffusion coefficient of acid red 12# in the mesoporous material was solved and simulated by using the Peterson heat conduction approximate formula and transcendental equation resolved by computer, which is helpful to study the adsorption mechanism of mesoporous materials.
Abstract: Electrochemical oxidation reactions of aniline in different systems were studied on a noble metallic oxide coating electrode, The results indicated that the degradation processes of aniline in neutral and alkaline solutions were similar, both with the appearance of the intermediates of benzoquinone and tartaric acid in successive, however, the degradation efficiency decreased in alkaline solution due to oxygen evolution, In an acidity system the difficulty of degradation increased because polyaniline appeared, and the degradation efficiency was the lowest, Para and meta intermediates, which were difficult to be degraded, formed during the electrochemical oxidation process and this was the major reason for the difficult degradation of aniline. A new technique was proposed to remove more intermediates of aniline, and the results indicated that this technique could not only effectively degrade waste water with aniline for the removal of chemical oxygen demand (CODCr) up to 82%, but also increased electric current efficiency and reduced energy consumption.
Abstract: Ammonium nitrogen (NH4+ -N) removal was investigated by using a novel suspended carrier. Honeycomb-like biofilms were formed among the columns on the suspended carrier. The bioreactor was operated at 24-29℃ and pH values of 7.8-8.2. When the influent COD and NH4+ -N concentrations were below 300 mg·L-1 and 78 mg·L-1 respectively, the effluent COD and NH4+ -N concentrations after 3 h operation were less than 50 mg·L-1 and 2 mg·L-1, respectively. After 4 h operation, when the in-fluent COD concentration varied from 150 to 350 mg·L-1 and the NH4+ -N concentration from 80 to 130 mg·L-1, the corresponding effluent concentrations were below 46 mg·L-1 and 3.5 mg·L-1 respectively. The ammonium-nitrogen biodegradation rate in the suspended carrier biofilm reactor is greater than that in the conventional activated sludge system. The honeycomb structure increases the porous ratio, decreases the wall thickness of biofilm and favors mass transfer and oxygen pervasion into the interior of biofilm, which provides better conditions for nitrobacteria growth and improves NH4+ -N removal efficiency
Abstract: The microstructure evolution of medium carbon steel during warm deformation includes dynamic recovery and recrystallization of ferrite, precipitation and spheroidization of cementite. The effect of initial microstructure on the microstructure evolution of a medium carbon steel (0.48% C in mass fraction) during warm deformation was investigated by hot uniaxial compression tests. The results indicate that the lamellar structure of pearlite in the initial microstructure of pearlite + ferrite is kinked, dissolved and spheroidized during warm deformation, with dynamic recovery and dynamic recrystallization of ferrite, the carbides precipitate from supersaturated ferrite, and then the duplex microstructure consisting of sub-micrometer ferrite grains and cementite particles is obtained, while the heterogeneous and zonal distribution of cementite particles and ferrite grains appear along the deformation direction. When the initial microstructure is martensite, the decomposition of martensite and the recovery and recrystallization of ferrite are enhanced by warm deformation. Because of the uniform distribution of carbon in the matrix, the fine equiaxed ferrite grains and homogeneously distributed cementite particles are formed.
Abstract: The static recrystallization behavior of a high temperature processing (HTP) steel containing 0.08% Nb (4#Nb steel) with coarse austenite was investigated by using a thermo-mechanical simulator Gleeble 1500. A low carbon steel containing 0. 049% Nb (2# Nb steel) was also studied as a comparison. The results indicate that the static recrystallization kinetics process of 4# Nb steel is slightly slower than that of 2# Nb steel at high deformation temperature. The recrystallization of 4# Nb steel is greatly retarded with decreasing deformation temperature. According to experimental data, a mathematical model of static recrystaUization was developed, which can provide theoretical guidance for designing the industrial rolling procedure.
Abstract: In order to solve the problem of drape defaults which usually appear on the surface of parts, pre-stretching experiments were done to investigate the effect of prestretching deformation on the yield platform of high-Si, low-Cr TRIP steel, and the microstructures were characterized by TEM before and after the tensile process to find out the forming mechanism of the yield platform. The result shows that the length of the yield platform always decreases with increasing prestretching deformation and disappears at the point of 1.0% prestretching. The specimens with more stable austenite possess shorter yield platforms under the same deformation condition. Yield platform formation of TRIP steel results from Cottrel atmosphere and stress relaxation-induced austenite transformation.
Abstract: Biaxial fatigue fracture feature of GH4169 super-alloy under the total strain amplitude control of in-phase (IP) loading and out-of-phase (OP) loading with phase angles of 45° and 90° at 650° was studied. The results indicate that cracks homogenously initiate on the surface of the samples under in-phase loading while the number of crack initiation decreases with the increase of non-proportional loading. The fatigue fracture exhibits apparently tear ridge in the radial direction under in-phase loading, however, there are tear planes with non-proportional loading. At the phase angle of 90°, the fatigue fracture shows the feature of all tear planes, which appears in the circumferential direction. On the boundary of two crack propagations the fatigue striations were found along the radial direction. At the instantaneous fracture area the depth of dimples became larger with the increase of non-proportional loading.
Abstract: Three kinds of Ni-based metal claddings (Ni46, Ni67, and Ni60/35WC) were deposited by the plasma jet cladding process. These cladding samples were then subject to cavitation erosion testing on the rotating disc cavitation test equipment. SEM, X-ray diffraction, micro hardness, and weight loss analysis were exploited to analyze the changes of the materials. The results showed the values of weight loss for all claddings were more than that of stainless steel 304. SEM images showed a large number of cracks occur and propagate under subsurface, for the existence of cavity and the other faults of structure, which significantly decreased the cavitation erosion resistance of the cladding materials, So the cavitation erosion is a typical fatigue failure process, Some new phases appeared and some old phases disappeared on the surface of the Ni60/35WC cladding after cavitation testing by X-ray diffraction. For Ni67 and Ni60/WC, the microhardness values of surface claddings became higher after cavitation and softer for Ni46.
Abstract: The structure and mechanical properties of the Al-5% Cu-0.8% Mn alloy conducted by electric pulse modification (EPM) at different parameters were studied by using mechanical testing and fracture analysis. The result shows that all of the specimens treated with EPM exhibit finer microstructure and good mechanical properties. Comparing with the specimens without EPM, the grain numbers per unit area increase more than two times, the tensile strength and elongation increase by 21%-35% and 1.8-2.5 times, respectively, when the pulse parameters are the voltage of 500 V, the time of 30 s and the frequency of 3 Hz.
Abstract: Based on the micro-multi-phase structure model of molten alloys, the thermodynamics of the Al-Si molten alloy structure under electric pulse was analyzed, and the changes in matrix micro-hardness and solidifying point of the Al-22% Si alloy under electric pulse were studied. It is shown that electric pulse promotes the decomposition of Si particles in colloidal state in the alloy melt, improves the homogeneous degree of the melt, and eliminates the heredity from raw material partially. Electric pulse modification increases the super cooling degree of the Al-22% Si alloy melt and enhances the supersaturated degree of Si particles in the matrix, thereby increases the micro-hardness of the matrix. The variation in micro-hardness of the alloy matrix indicates that the alloy melt structure was sensitive to the change in electric pulse frequency.
Abstract: The experimental investigation of sodium penetration and expansion of carbon-based cathodes during aluminum electrolysis was carried out in a laboratory cell. The results show that the addition of B2O3 can reduce the rate of sodium penetration but increase the rate of sodium expansion at the final stage. The addition of TiB2 results in lower rates for both sodium penetration and sodium expansion. SEM-EDS analysis indicates that TiB2 + B2O3 presents within the areas of binder phase of the cathode, which may play a role in reducing the rates of sodium penetration and expansion.
Abstract: AZ31 magnesium alloy billets were prepared by spray forming technique, then the alloy billets were hot rolled into compact plates. The microstructure and mechanical properties of the alloy were investigated. The result indicates that the spray formed alloy has a fine microstructure with an average grain size of 20 μm. The finer and mechanical properties were gained by the compacted processing, dynamic recrystallization and annealed static recrystallization. The fracture surfaces of the as-hot rolled sample show a typical brittle fracture character while the as-annealed sample displays a mixed mode of brittle fracture and tough-hess fracture.
Abstract: Low-silica X zeolite (LSX) with the molar ratio 2.0 of SiO2 to Al2O3 was prepared by introducing the crystallization directing agent (CDA) under aging at room temperature(15-30℃)and crystallizing at 100-110℃. The crystal structure of LSX was characterized by XRD. The effect of CDA (17Na2O·6SiO2·Al2O3·250H2O) on the crystallization of LSX was studied. The results showed that the additive of CDA aged for 5 h could inhibit from impurity hydroxysodalite (HS) in LSX, but could not speed up the rate of crystallization. The study on the ratio of raw material showed that the purity of LSX was greatly influenced by the changes in molar ratio of H2O/(Na2O + K2O) and Na2O/(Na2O + K2O). The crystallinity of product LSX raised with increasing reaction temperature and aging time. The fine purity and crystallinity of the product could be obtained when aging for 12 h at room temperature (25-30℃) and crystallizing for 3 h at 110℃, and the molar ratio Si/Al of product LSX was 1.02±0.03.
Abstract: In order to study the working performance of cast-steel cooling staves at high temperature, the temperature field was investigated by hot test. The strain distribution on the cool face of the stave was studied for the first time by installing strain gauges. The highest temperature on the hot face of the stave was about 600℃, which is lower than the transformation temperature of caststeel. The strain was about-5×10-4 at the centre of the cool face, while the average strain all around was-3×10-4. The heat resistance of the cooling pipe was analyzed. It was verified that the cooling pipe was fused well with the stave body, which means no gaps between them. The special yield phenomenon of cast-steel was validated that the strain distribution would be visibly improved after the thermal shock.
Abstract: Based on the analysis of self-adaptive functional structure of stopper in different working stages, some main problems of stopper were found with motion simulation analysis by using ADAMS software, and then a stopper was optimized and designed with self-adjustable structure without overconstraints. Simulation results showed that the performance of the stopper was improved with the benefit of more reliable working process. Meanwhile, the ability of self-adjustment and self-adaptation was advanced for eliminating the sensitivity to environment. It is indicated that the self-adjustable structure of mechanism has the engineering practical value and great prospect.
Abstract: In order to find out the forming rules for axial parts with super large area reduction during twice cross wedge roiling, the extreme roiling experiment under different process conditions was done on an H630 rolling mill. The effect rules of process parameters on the roiling quality were achieved. It is shown that process parameters have determinant effect on the internal defect and tension fracture of the parts with super large area reduction. If the parameters are proper, the qualified axial parts with large area reduction can be produced.
Abstract: Due to the noise disturbance from surrounding equipments and environment in gear fault diagnosis based on acoustic signal analysis, a novel method combined with independent component analysis and auto-correlation was proposed. Independent component analysis was used to separate characteristic signal and interference signal. And then auto-correlation was used to extract the periodic component of characteristic signal. Experimental results indicate that the proposed approach could reduce strong background noise and extract fault feature form gear acoustic signal.
Abstract: In order to solve the problem of impulsive features extraction from strong noise background, an adaptive multiscale morphology analysis (AMMA) algorithm was proposed. Corresponding to the analysis signal, the length scale and height scale were defined separately to select structuring elements for multiscale morphology analysis. An adaptive algorithm based on the information of local peaks of the signal was discussed. Numerical simulation experiments show that the proposed AMMA algorithm is better than the single-scale morphology analysis algorithm for extracting morphological features, and avoids the drawbacks of the ambiguity of selecting structuring elements and the dependence of empirical rules. The proposed AMMA algorithm is also examined in morphology analysis of the experimental signal measured from a bearing with faults. The results confirm that the proposed AMMA algorithm is able to extract various features clearly.
Abstract: A method for designing Hilbert transform pairs of orthogonal and biorthogonal wavelet bases was proposed, which can translate the problem into resolving algebraic equations via a flat fractional delay filter based on the sufficient and necessary condition for constructing wavelet. It avoids performing spectral factorization. Experiments show that the dual-tree complex wavelet transform (DT-CWT) based on the wavelet bases constructed by this method can more fit to extract features than the real discrete wavelet transform (DWT).
Abstract: A kind of linear discrete-time system with state time-delay and multirate control setting was studied. By using the methods of lifting technique, difference operator and state vector augmentation, the state equation was changed to another equation with no time-delay. And the multirate preview control problem was reduced to the single-rate one which includes an integrator. The desired preview controller was obtained by the standard linear quadratic (LQ) optimal preview control theory. The applicability of the present results was verified by a numerical example.
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
