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15 November 2003, Volume 24 Issue 11 Previous Issue    Next Issue
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Key technologies of centralized soccer-robot vision system Fang, Shuai (1); Hu, Ying (1); Xu, Xin-He (1) 2003, 24 (11):  1029-1032.  DOI: - Abstract ( 228 )   HTML   PDF (257KB) ( 818 )   Introducing the frame of NewNEU soccer-robot vision system, its key technologies were explicated including image correction, image segmentation and identification algorithm. The image distortion was solved by projection correction and geometric correction, and based on the characteristics of soccer robots, HSV color model was applied to set up color partitioner and color database to implement the partition of object images. A more reasonable and anti-jamming design was put forward by comparing and analyzing various representative color tag designs with a fast and relatively exact successive approximation algorithm given correspondingly for angular compensation. References | Related Articles | Metrics

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Fused neural network based on BP algorithm Su, Yu (1); Zhao, Hai (1); Wang, Gang (1); Su, Wei-Ji (1) 2003, 24 (11):  1037-1040.  DOI: - Abstract ( 343 )   HTML   PDF (253KB) ( 1115 )   A temperature model, as a nonlinear dynamic one, was set up on a basis of fused neural network for the hydroelectric plants. The VLBP (Variable Learning-rate Back Propagation) algorithm was utilized to update network gradients and weight values with the aim of eliminating the slowness in the drill application of the neural network which is easy to get into local extremum. In applications of the model, several temperature-acquisition parameters were got for sensors, then use such parameters to drill off-line the fused neural network. Thus, the real-time on-line forecasts will be available to the temperature parameters of hydroelectric power generator if using the drilled network. Actual accuracy of the model can be up to 96.5%. So, the model can be regarded as meeting the requirements of the simulation. References | Related Articles | Metrics

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FIFA-based topic similarity computation modal Zhu, Jing-Bo (1); Chen, Wen-Liang (1) 2003, 24 (11):  1041-1044.  DOI: - Abstract ( 219 )   HTML   PDF (107KB) ( 715 )   An event topic similarity computation technique for the fifth TDT technique-linking detection was put forward. Domain knowledge base is used to upgrade topic similarity computation technique from lexical analysis to domain knowledge analysis. The linking detection technique is used to decide whether two documents (or stories) are on the same event topic. There are two steps in the analysis procedure which includes using FIFA modal to identification content topic, and using LDM modal to compute event topic similarity. Experiment results show that precision and recall percents of the model are 64% and 69%. References | Related Articles | Metrics

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Discovery of trust routing for mobile ad hoc networks Wang, Cui-Rong (1); Gao, Yuan (1) 2003, 24 (11):  1045-1048.  DOI: - Abstract ( 236 )   HTML   PDF (179KB) ( 905 )   Reviewing the defects of existing ad hoc network route protocols, a new method searching trust routing for mobile ad hoc network was presented on the basis of the peculiarity of ad hoc network. The method was applied to DSR protocol approved by IETF. NS2 simulation experiment showed that the method is feasible and effective. Trust probability was suggested to describe the probability that a node may be acted as next hop, with an arithmetic given to calculate the trust probability. It's an empirical proof that how a rout designer trusted an evidence is dependent not only on recommendations from third parties but more important on his/her own experience. A trust model was thus formalized, which is available to manage the trust relation between strangers. The model can deal with incomplete and uncertain evidence so as to make up the defects of existing ad hoc route protocol. References | Related Articles | Metrics

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Microstructures evolution of the semi-solid A2017 alloy during reheating Wang, Shun-Cheng (1); Wen, Jing-Lin (1); Chen, Yan-Bo (1); Li, Ying-Long (1) 2003, 24 (11):  1049-1052.  DOI: - Abstract ( 242 )   HTML   PDF (165KB) ( 850 )   The semi-solid A2017 alloys provided with shearing/cooling roll (SCR) technology were reheated, and its microstructural evolution was studied by means of optical microscope, SEM and graphical analyzer. The results indicated that the mean diameter of grains increases, volume fraction of liquid increases and getting spheriform grains with the prolongation of isothermal holding time. In addition, the grains grow up and are sphericized faster with the reheating temperature rising. The group of reheating process parameters is reheating temperature 580°C/holding time 40-60 min or 600°C/20-40 min with mean diameter of grains 70-90 μm and the got volume fraction of solid is 70%. Such a temperature/time group is suitable for thixo-forming. Based on the experimental results, the microstructural evolution mechanism of the semi-solid A2017 alloy reheated in semi-solid state was analyzed. It is found that in the early stage of the whole reheating process, the volume fraction of liquid is low and grains grow up fast mainly through crashing and fusing, while grains grow up slowly and are sphericized mainly through elements diffusion with increasing volume fraction of liquid as the temperature holding time prolonged. References | Related Articles | Metrics

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Effect of interlayer on interfacial bonding properties of stainless clad sheets Zu, Guo-Yin (1); Yu, Jiu-Ming (1); Wen, Jing-Lin (1) 2003, 24 (11):  1053-1056.  DOI: - Abstract ( 313 )   HTML   PDF (192KB) ( 767 )   In view of the features of diffusion welding process, some interlayer materials were used to facilitate the stainless steel sheet to clad the carbon-steel sheet. A series of tests were done to investigate various influential factors on cladding process, such as pressure, temperature, holding time and protective gas. It is found that some interlayer materials can provide optimum technological parameters to cladding process. The stainless steel sheet can be clad onto carbon-steel sheet if taking silver-copper-zinc solder as interlayer or sandwiched layer for cladding at 750°C with 25% reduction in first pass. Pure argon has proved that it is an effective protective gas from surface oxidation. In addition, the influence of various parameters on cladding results was also analyzed theoretically. References | Related Articles | Metrics

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Brittle transition temperature of 400 MPa supersteel Gao, Cai-Ru (1); Li, Hong-Bin (2); Liu, Xiang-Hua (1); Wang, Guo-Dong (1) 2003, 24 (11):  1057-1060.  DOI: - Abstract ( 292 )   HTML   PDF (213KB) ( 1229 )   Series impact tests were carried out to measure a 400 MPa-class super-steel using the series impact work. The brittle transition temperature curve was obtained. The brittle transition temperature or ductile-brittle transition temperature (DBTT) of the steel was determined as-80°C according to the integrated energy consumption and fracture morphology of the tested samples. Compared with that of other steel sheets of the same composition but rolled in different ways, the reasons of such a lower temperature were analyzed. A conclusion was thus drawn that the decreased DBTT and the improvement of low-temperature ductility can be attributed to the combination of composition and rolling technique with microstructure and other factors. Low contents of S, P and Si in tasted samples are beneficial to the decreasing of DBTT as well as the microalloying element Nb. In addition, refined grain and subgrain strengthening play an important role in decreasing DBTT, and TMCP technique can refine ferrite grain so as to benefit DBTT decreasing. References | Related Articles | Metrics

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Synthesis of YBa2Cu3O7-δ superconducting powder through sol-gel process Li, Feng-Hua (1); Wang, Jue (1); Liu, Chang-Sheng (1); Fan, Zhan-Guo (1) 2003, 24 (11):  1061-1063.  DOI: - Abstract ( 242 )   HTML   PDF (162KB) ( 1258 )   Homogeneous YBa2Cu3O7-δ powder was prepared through sol-gel process. The citric acid was used as complexing agent to form macromolecule compound with Y3+, Ba2+ and Cu2+ ions. After dehydration the compound grew into small particle clusters which bonded together to form continuous three-dimension net. The pH value of citrate solution should be controlled in a range from 6.4 to 6.7 to prevent from forming Ba(NO3)2 sediment and ensure the quality of gel. It' s preferable to control the evaporating temperature at 300°C so as to form gel in shortened time continuously along with its spontaneous combustion process at the same temperature. Thus the process is simplified. The temperature required for synthesizing YBa2Cu3O7-δ powder is about 880°C, at which the particle size is about 0.2-1 μm. References | Related Articles | Metrics

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Composite WO3-TiO2 photocatalyst for photodegradation Liu, Kui-Ren (1); Han, Qing (1); Chen, Jian-She (1); Wei, Xu-Jun (1) 2003, 24 (11):  1064-1067.  DOI: - Abstract ( 244 )   HTML   PDF (163KB) ( 867 )   The nano-crystal composite film photocatalyst WO3-TiO2 was prepared by sol- gel process. The effects of various tungstates with their doping amounts, the number of coating layers, the dissolved oxygen, the roasting temperature/time and various substrates on the photocatalytic activity were investigated through the photodecomposition action of films to the solution of Rhodamine B. Taking the parous Ti plate as a substrate, doping amount of (NH4)5H5 [H2(WO4)] ·H2O x(W)=1.5%, cladding a layers of the composite WO3-TiO2 films and roasting for 1 hour at 500°C, the composite WO3-TiO2 film with the highest photocatalytic activity can be obtained and its photocatalytic activity is 1.5 times higher than that of pure TiO2. Meanwhile the phase of the composite WO3-TiO2 film thus formed is attributed to anatase phase. References | Related Articles | Metrics

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Influence of fine α-Al2O3 powder on the properties of the magnesia-calcia refractories Yu, Jing-Kun (1); Dai, Wen-Bin (1) 2003, 24 (11):  1068-1070.  DOI: - Abstract ( 237 )   HTML   PDF (157KB) ( 670 )   Adding fine α-Al2O3 powder to magnesia-calcia refractories, the influence of the weight of additive on the sintering behavior and hydration resistance of refractories was studied. The results showed that the sintering behavior and hydration resistance could be both improved effectively by adding fine α-Al2O3 powder. The bulk density of the refractories will increase with the increasing weight of the additive if it is less than 1% . If the weight of the additive is more than 1% , the bulk density of the refractories will decrease and the sintering behavior will weaken. The hydration resistance will be improved if the weight of the fine α-Al2O3 powders increases from 0 to 5%. References | Related Articles | Metrics

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Preparation of foam aluminium by powder metallurgy process Wei, Li (1); Yao, Guang-Cun (1); Zhang, Xiao-Ming (1); Luo, Hong-Jie (1) 2003, 24 (11):  1071-1074.  DOI: - Abstract ( 261 )   HTML   PDF (210KB) ( 1644 )   The effects of some parameters as air-separating protection, blank compaction and forming temperature on the compactedness, porosity and pore morphology of foam Aluminum were discussed in detail, especially the mechanism of foaming process. It was found that increasing pressure for blank can improve the compactedness of blanks so as to make foam aluminium materials with homogeneous pores. Foaming temperature, as one of the main influencing factors on foaming process, should be controlled higher than the melting point of Al or Al-alloy to a certain extant in order to keep a reasonable viscosity. Thus, the foam aluminum with homogeneous pores and high porosity is available. As shown by experiments, such materials should be made on conditions that they shall be protected with molten salt under 300 MPa pressure at 675-680°C. References | Related Articles | Metrics

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Dynamic study on three-leg parallel robot Hu, Ming (1); Yuan, Suo-Xian (1); Cai, Guang-Qi (1) 2003, 24 (11):  1075-1077.  DOI: - Abstract ( 293 )   HTML   PDF (219KB) ( 1202 )   A dynamics model for a new developed three-leg parallel robotic mechanism was established by Lagrange approach. The model, as an explicit expression, is convenient to calculate, providing a basis on which the real time control of forces and torques are available to the robot. The operability and the dynamic behavior of the robot were analyzed using the dynamics model, with the robot evaluated and simulated dynamically by means of an inertia ellipsoid for operability. The results showed that the greater characteristic coefficient of the robot is, the worse the operability will be within the workspace of the robot. So, if the characteristic coefficient is not higher than 2, the operability of the robot shows well through the geometrical representation. As a conclusion, the dynamic behavior of the robot is good and fairly applicable. References | Related Articles | Metrics

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Kinematic behavior of a new parallel robot Meng, Xiang-Zhi (1); Wu, Yi (1); Liu, Zhi-Feng (2); Cai, Guang-Qi (1) 2003, 24 (11):  1078-1081.  DOI: - Abstract ( 213 )   HTML   PDF (260KB) ( 1185 )   A new developed 3-leg parallel robot was concerned with its kinematic behavior, of which the related equations and Jacobian matrix were presented with its workspace analyzed. The singularity and smartness of the robot mechanism were discussed by the way of ascertaining the indices of operability and condition number of Jacobian matrix. The results of simulation show that the robot has workspace symmetrical about X-axis. The robot's operability W varies in a range from 0.8 to 2.45 within its whole workspace, i.e., an excellent operability without singular/uncertain position. Meanwhile, the matrix condition number C(J) varies in a range from 1.0 to 6.2 without sudden break if picking up any coordinated axis (X,Y,Z) to indicate its value. These reveal that the robot is of high kinematic smartness. References | Related Articles | Metrics

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Applications of co-net to scientific instruments equipment based on concurrent engineering Ma, Shi-Xiao (1); Zhang, Guo-Zhong (1); Xu, Wan-Hong (1) 2003, 24 (11):  1082-1084.  DOI: - Abstract ( 355 )   HTML   PDF (141KB) ( 1434 )   The theory of concurrent engineering was introduced to constructing a co-net of scientific instrumental equipment as a guidance, thus widening the fields to apply the theory to practice and offering a solution to actual problems by use of concurrent engineering. Discussing the construction of such a co-net and procedure is needed to implement it, a date management system and interface modules were developed so as to set up a design system for the co-net on the basis of concurrent engineering. With a total-text software used for technology management, the system and date are of rational design and guaranteed to be safe, stable, easy, to maintain and expansible. The design of the co-net carried out, featured with broad coverage and a combination of browse with more information was provided. It provides a new theoretic basis and creative mode to similar networks. References | Related Articles | Metrics

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Fault diagnosis for vacuum metallurgical system by way of fuzzy clustering Wang, Qing (1); Ba, De-Chun (1); Jin, Yu-Fei (2); Wang, Xiao-Dong (1) 2003, 24 (11):  1085-1087.  DOI: - Abstract ( 399 )   HTML   PDF (205KB) ( 720 )   An intelligent fault diagnosis model based on fuzzy clustering algorithm is put forward aiming at the high-duty vacuum metallurgical system of which the possible faults take place frequently and unwarnedly and need quick and exact fault diagnosis. The model is highly self-learning and self-organizing especially applicable for the fault diagnosis to heavy-duty and complicated vacuum systems. Describing the theory of fuzzy clustering algorithm, the paper presents the procedure of fuzzy fault diagnosis, with an actual diagnosis process given as an example to show the intelligent fault diagnosis for RH-KTB vacuum metallurgical system. Thus, effectiveness of the algorithm is proved through an analysis of the exemplification. References | Related Articles | Metrics

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Stability of the ternary complexes of Pd(II)-phenylimid-l,10-phenanthroline-amino acid Sun, Ya-Guang (1); Wei, De-Zhou (1); Gao, En-Jun (2); Wang, Chuan-Sheng (2) 2003, 24 (11):  1088-1091.  DOI: - Abstract ( 305 )   HTML   PDF (185KB) ( 546 )   The stability constant lgK and relevant characteristic constants ΔlgK and lgX of ternary complexes of Pd(PIP) (Aa)+ were determined by pH potential titration at 37°C with μ(ionic strength)=0.1 (KNO3) in the mixed medium of ethanol/H2O of which the ethanol volume ratio was 10%, 20%, 30%, 40% or 50% individually each time, Where PIP=Phenylimid-1,10-Phenanthroline was taken as the 1st ligand and Aa-=gly-, phe- and leu- as the 2nd one. The results show that lgK≥14 which implies that there is very strong bond in the ternary complexes, and that both ΔlgK and lgX are greater than the statistical expected value, which mean there is extra stability in the ternary complexes. The contributing ratio of electronic effect and hydrophobia effect (aromatic nucleus stacking) in extra stability was calculated. The results show that when the volume ratio of ethanol is 30%, hydrophobic effect (aromatic nucleus stacking) comes to its maximum value. References | Related Articles | Metrics

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Experimental analysis of constructional parameters of nugget mining in Xiaoguanzhuang iron mine Zhang, Guo-Lian (1); Qiu, Jing-Ping (1); Song, Shou-Zhi (1) 2003, 24 (11):  1092-1095.  DOI: - Abstract ( 292 )   HTML   PDF (224KB) ( 668 )   With increasing mining depth, the sublevel height increased correspondingly to 12.5 m from 10 m so as to decrease mining cost. A 3-dimensional model experiment was therefore carried out in lab with the intention of determining the constructional parameters such as drift intervals and drawing pace to meet the mining requirements after the sublevel height up to 12.5 m. The experimental data were processed through regression analysis, and the regression equations were solved using Matlab programming to express the relationships between drift interval/drawing pace and the rate of ore recovery/rate of rock drop-in/rate of undiluted ore recovery. Then, based on such relationships, some suggestions are put forward for the constructional parameters of nugget mining in the mine area, i.e., the optimum combination of drift interval with drawing pace is l2.5 m× 5-6 m after an overall consideration of various ore recovery indices. References | Related Articles | Metrics

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Analysis of the maximum displacement of isolation layer for base-isolated buildings with rubber bearings Gu, Wei (1); Li, Yi (1); Liu, Bin (1); Lou, Yong-Lin (2) 2003, 24 (11):  1096-1099.  DOI: - Abstract ( 287 )   HTML   PDF (1679KB) ( 722 )   Through an equivalent interlaminar shear model with multi-degree of freedom for base-isolated buildings with laminated rubber bearings, the maximum displacement of isolation layer is discussed, adopting dynamical time-history analysis. The results show that the influencing factors on the maximum displacement of isolation layer are mainly the site classification, earthquake intensity, structural period of base-isolated building and equivalent viscous damp ratio. It was found that the amplitude of displacement of isolation layer is minimum in the site class I and adjusting the damp ratio can control efficiently the amplitude of displacement. By way of regression-analysis, a simplified calculation formula of maximum displacement of isolation layer is provided for regular base-isolated buildings of low and multi-storey in site class I, II and III, of which the accuracy will meet the requirements of engineering design. References | Related Articles | Metrics

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- - 2003, 24 (11):  1100-1103.  DOI: - Abstract ( 246 )   HTML   PDF (183KB) ( 814 )   - References | Related Articles | Metrics

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- - 2003, 24 (11):  1104-1107.  DOI: - Abstract ( 223 )   HTML   PDF (1899KB) ( 610 )   - References | Related Articles | Metrics

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- - 2003, 24 (11):  1108-1111.  DOI: - Abstract ( 249 )   HTML   PDF (159KB) ( 1051 )   - References | Related Articles | Metrics

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- - 2003, 24 (11):  1112-1115.  DOI: - Abstract ( 206 )   HTML   PDF (112KB) ( 585 )   - References | Related Articles | Metrics

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- - 2003, 24 (11):  1116-1118.  DOI: - Abstract ( 214 )   HTML   PDF (151KB) ( 586 )   - References | Related Articles | Metrics

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- - 2003, 24 (11):  1119-1122.  DOI: - Abstract ( 250 )   HTML   PDF (1129KB) ( 1002 )   - References | Related Articles | Metrics