Abstract: There is great desertification in the east of Hainan Island of China due to over-mining of ilmenites. The effective methods to combat desertification are monitoring the change of land with remote sensing, licensing the rights of mining ilmenites rationally, and organizing the moderate reclaim. Based on the difference of sandy land types on the spatial constructions, geostatistical texture was used to monitor desertification, and the discrimination degree of sample selection could be increased by using variogram texture to increase the difference of different kinds of sandy land. The results show that the maximum likelihood classification based on variogram texture and spectral bands can perfectly define the grades of beach sandy land and inner desertification, and the maximal classification precision comes up to 92.4%, which proves that geostatistical texture is effective in the application of desertification monitoring.
Abstract: According to the grade spatial distribution of regular volume data from interpolation, the deposit volume data was divided into several sections. The 3D Delaunay algorithm was adopted to separate the 3D point set in each section and to extract the surface of those points, and the local model based on irregular tetrahedral was built up. All of the local models were composed by OpenGL's blend technique to achieve the simulation process of deposit. The idea of "the part model building, the conformity displays" was used to resolve the contradiction between rendering speed and detailed expression and give out the method of mineral reserve computation. The model analyzed with OOA constructs the data structure of base class, and has well aoolications and expansibility.
Abstract: The buildings settlement nearing a official building foundation pit in Jiangsu province of China was calculated. The calculated results were compared with the measured ones, and the reasons for their difference were pointed out. The factors influencing the buildings settlement nearing a foundation pit were summarized and their effects on the settlement were discussed in detail by analyzing the measured settlement values.
Abstract: A desulphurization experiment was carried out by adding BaO and B2O3 to an CaO-based slag. The result shows that the addition of BaO can decrease the melting point and viscosity of the refining slag, improve effectively the dynamics condition of metal-slag reaction, and increase the desulphurization ability of the refining slag. When the BaO content is between 15% and 25%, the desulphurization rate is more than 90%. But the addition of B2O3 has little influence on the desulphurization rate, just can be added instead of CaF2 as a flux.
Abstract: The stability of a planar liquid/solid interface of solidification in pure melt under perturbation of a small far-field flow was studied by using asymptotic analysis. A dispersion relation between the wave number and perturbation amplification rate was derived, and the morphological stability of planar liquid-solid interface of solidification was determined. The results reveal the mechanism of the transition from planar interface to cellular interface in directional solidification.
Abstract: Based on the isothermal treatment and continuous cooling test of an Mn-Cu-Nb-B low carbon bainitic steel, it was found that several types of intermediate transformation could be formed in the range of 500-700℃. Cooling rate and finish cooling temperature have much effect on the final microstructure and mechanical properties of the steel. When the finish cooling temperature was selected around 630℃, a proper combination of quasipolygonal ferrite, granular bainite and fine M/A could be obtained. The yield stress of this type of microstructure could reach 600 MPa, with a better plasticity and low-temperature impact toughness. A proper control cooling process influences the intermediate transformation products, in this way the mechanical properties of a low carbon bainitic steel can be fairly optimized.
Abstract: 25Mn-3Si-3Al TWIP steel sheets were developed by hot rolling, cold rolling and annealing treatment processing. The mechanical properties, microstructure and fracture mechanism of the sheets were investigated and the crystal textures were confirmed by X-ray diffraction measurement. The results show that the fracture mechanism of the sheets is typical toughness fracture under the condition of tensile failure, and the microstructure is austenitic with a large number of annealing twins before tension. During tension the annealing twins change into deformation twins, which make the strength and plasticity of the sheets increase. The textures formed during annealing treatment are advantageous to the plasticity of steel sheets.
Abstract: Several methods to improve the linearity of anisotropic magnetoresistance (AMR) sensors were suggested based on the analysis of the generation of nonlinearity in magnetoresistive sensors of metallic films. Ni80Fe20 and Ni65Co35 AMR thin films were prepared by DC magnetic sputtering. Some AMR sensors were made by the micro-fabrication technique, and the testing results were also presented.
Abstract: The flow stress behavior of a new type Al-Cu-Li system alloy during hot compression deformation was studied in the strain rate range from 0.01 to 10 s-1 and the temperature range from 300 to 500℃ by isothermal compression test on a Gleeble 1500 thermal-mechanical simulator. The results show that the flow stress of this new type Al-Cu-Li system alloy decreases with the increase of deformation temperature and increases with the increase of strain rate. The peak flow stress during high temperature deformation can be represented by Z parameter in a hyperbolic sine function. The analytical expression of peak flow stress was fitted with the hot deformation activation energy of 239.02 kJ·mol-1.
Abstract: Based on the investigation of the rheological and thixotropic behavior of semi-solid AZ91D slurry, a thixotropic model describing the apparent viscosity of the slurry was established by the curve fitting method. A specific program used for calculating the apparent viscosity of AZ91D slurry during thixodiecasting was developed and embedded into the CastSoft simulating program. The flow field and the temperature field during thixo-diecasting process were simulated using the improved program. The results show that the filling speed and initial temperature of the slurry have great effects on the flow patterns of semi-solid AZ91D slurry during thix-filling, the optimum filling speed of slurry is between 2 and 5 m·s-1 and the optimum temperature is from 570℃ to 580℃.
Abstract: The molecular dynamic simulation and the embedded atom method (EAM) were used to simulate the influence of thermal pulse with different frequencies on the transformation of Cu from crystalline state to non-crystalline state. The results show that the average system temperature is higher than the calculated equilibrium melting point of Cu while the transformation occurs which should be an overheated melting process, It is impossible to transfer the crystalline state into non-crystalline state under thermal pulse. With increasing thermal pulse frequency, the minimum thermal pulse energy and system overheating degree decrease.
Abstract: This paper investigated the effects of pressureless sintering in suit synthesis process on the density, physical properties and microstructure of ZrB2/B4C ceramic composites. The results showed that, as the sintering temperature increasing and the holding time extending, the density increased first and then decreased, and the maximum relative density of the composites synthesized at 2 060℃for 30 min was 93.2%; the hardness rised with increasing temperature and its value reached to the peak at 2 070℃; opposite to the hardness, the fracture toughness decreased from 4.04 MPa·m1/2 at 2 000℃ to 2.36 MPa·m1/2 at 2 060℃.
Abstract: A new type of broadband radar absorbing material (RAM) was synthesized with carbonyl iron and conduction polyaniline (PAn). By SEM and TEM analyses the microstructure of the product was carbonyl iron coated by conduction polyaniline, and the single absorbent layer of 0.9 mm with the composite absorbent attenuated about 5 dB microwave in the range from 6 to 18 GHz. The bandwidth could be broadened and the effect of absorbing could be improved by further study. It should be applied as a useful RAM for its lightweight, corrosion resistant and broad-band.
Abstract: Based on the experiment of dust removal in a granular layer at normal temperature and the analysis of the Based on the experiment of dust removal in a granular layer at normal temperature and the experimental results, the influence of filter particle diameter, layer thickness and filtration velocity on the dust removal efficiency was researched. The result gave the optimal filter particle diameter, layer thickness and filtration velocity.
Abstract: The construction, characteristic and shift strategy of a taper work roll were investigated for the problem of edge drop control during continuous cold rolling. A finite element model was built to analyze the strip shape control capability of the taper work roll, common crown work roll and SmartCrown work roll contrastively, and the application of this new strip shape control technology to real production was discussed based on the debugging tests on a large production mill. The results show that the use of a taper roll can reduce the edge drop and total crown of strip steel efficiently.
Abstract: A nonlinear parameter estimation method was adopted to determine the thermal diffusivity of a xonotlite-type calcium silicate insulation material. The measurements were performed with a laser-flash apparatus by rear-face detection of the temperature response of the three-layered sample, where the insulating material was sandwiched between two iron slices. The thermal diffusivity was evaluated by fitting the theoretical curve with the recorded temperature-time one. The nonlinear parameter estimation technique can simultaneously estimate the thermal conductivity, heat transfer coefficient and absorbed energy. Based on experimental results, the optimal thickness range of the insulation material in the sample was suggested from 1.6 to 1.9 mm. The effect of thickness and contact resistance on measurement uncertainty was estimated within 5.8%
Abstract: This paper studied two-dimensional steady laminar flow over a porous medium stretching surface with suction or injection. The homotopy analysis method, a kind of analytical method, was applied to solve the problem. The solution presents representative profiles for the dimensionless velocity and the skin friction coefficient at different permeability and injection parameters.
Abstract: In view of safety the elementary and industrial analyses of coal samples were conducted, a systematic experiment was performed to investigate the minimum ignition temperature (MIT) of Zhangcun and Changcun meager-lean coal in a G-G furnace, and the effect of dust concentration, spray-air pressure and dust particle size on the MIT was analyzed. The results show that the TIM increases with the decrease of dust concentration and the increase of spray-air pressure and dust particle size. A linear regression was conducted and the functional relationship was found, which can afford reference for the security of meagerlean coal's industry application.
Abstract: A kernel partial least squares (KPLS) method based on dual optimization was proposed,which was expressed by least squares support vector machine. The KPLS formulae in the form of dual opti-mization were deduced, which had the style of least squares support vector machine. The optimization problem was constructed in a prime space, the dual problem was solved in a eigenspace by the kernel skill and the solutions were the same as nonlinear KPLS.The model was illustrated with some examples. The results show that the proposed method is effective and superior.
Abstract: To solve the disadvantages of the basic ant colony algorithm including slow convergent speed and incidental stagnation behavior, a new ant colony optimization algorithm, named the ant system with scouting subgroup (ASSS), was proposed. In the algorithm a small part of ants were separated and formed a scouting subgroup that random moved at a certain probability to increase results diversity. The pheromone update strategy used the iteration-best-ant and global-best-ant at the same time to make use of both iteration-fruit and history-fruit. LK mutation factor was employed to locally optimize the search results of each step. Three typical traveling salesman problems (TSP) were tested, and the results show that this proposed algorithm can avoid prematurity and speed up convergence.
Abstract: According to zero-watermarking, a zero-embedding algorithm for multiple watermarks was proposed based on wavelet and chaos. Matching matrixes were structured with wavelet zerotree structure, and used to load multiple binary watermarks scrambled by chaotic sequences. The zero-embedding of multiple watermarks ensured the watermarks' invisibility thoroughly, and could implement a blind detection by stage. Experimental results show that the technique has stronger robustness, better security, dependability and feasibility.
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
