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15 January 2010, Volume 31 Issue 1 Previous Issue    Next Issue
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Modified Kalman filtering for linear discrete-time systems with correlated noise Liu Wei (1); Zhang, Hua-Guang (1) 2010, 31 (1):  1-3+7.  DOI: - Abstract ( 259 )   HTML   PDF (615KB) ( 894 )   The state estimation problem of linear discrete-time systems was studied in case the system noises and observation noises are both correlated. A modified Kalman filtering which is in combination with the Hamiltonian approach of Kalman filter was proposed. Compared with the classic Kalman filtering, the proposed algorithm needn't calculate the Kalman gain matrix and conditional mean of observation sequence, and it obtains the optimal performance under conditions that less regression equations are needed and they are easily calculated. Thus, the algorithm is easy to use. Simulation results demonstrated that the algorithm can effectively estimate the system states. References | Related Articles | Metrics

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Robust H∞ control of a class of nonlinear descriptor systems with state delay and parameter uncertainty Yang, Dong-Mei (1); Yu, Shi (1); Quan, Xin (1) 2010, 31 (1):  4-7.  DOI: - Abstract ( 295 )   HTML   PDF (159KB) ( 775 )   The robust H∞ control of a class of nonlinear delayed descriptor systems with linear fractional parameter uncertainties was investigated. Based on linear matrix inequality (LMI) theory, the sufficient conditions for the existence of memory-state feedback controllers was derived from the strict LMI design method. Then, the controllers guaranteed that the closed-loop descriptor systems was asymptotically stable with null solution and had a H∞ norm constraint γ, for arbitrary delay d>0 and all admissible uncertain parameters. The result of a numerical example showed the feasibility and effectiveness of the proposed method. References | Related Articles | Metrics

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On the hybrid modeling method of cobalt oxalate grain size distribution in hydrometallurgy synthesis process Zhang, Shu-Ning (1); Wang, Fu-Li (1); You, Fu-Qiang (1); He, Da-Kuo (1) 2010, 31 (1):  8-11.  DOI: - Abstract ( 320 )   HTML   PDF (357KB) ( 754 )   Due to lack of efficient measuring means, the real-time measurement is unattainable to the grain size distribution of cobalt oxalate in its hydrometallurgical synthesis process. A hybrid modeling method of the distribution was therefore proposed combining SVM with the dynamic mechanism model of the synthesis process to predict the grain size distribution. Analyzing the mechanism of synthesis process, the population balance equation and material balance were used to develop a dynamic model for the distribution, with SVM used to compensate for the error resulting from the dynamic characteristic in synthesis process, which could not be revealed by the dynamic mechanism model. Simulation analysis was verified that hybrid method is more effective in comparison with the dynamic mechanism model. The application of the proposed method to a practical industrial process showed its satisfactory results. References | Related Articles | Metrics

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Recognition based on common spatial patterns and ANN for brain-computer interface signal Ye, Ning (1); Sun, Yu-Ge (1); Wang, Xu (1) 2010, 31 (1):  12-15.  DOI: - Abstract ( 476 )   HTML   PDF (461KB) ( 1000 )   Classifies the EEG signals of different ideas based on the common spatial patterns(CSP) and LVQ-ANN. EEG is the control signals of brain-computer interface(BCI), which are collected from one's scalp by electrodes to extract and classify the EEG features so as to form a communication system that does not depend on the brain's normal output channels of peripheral nerves and muscles. With the original EEG signals preprocessed by wavelet packet decomposition, the CSP is introduced to decompose further the EEG signals from the specified subbands of wavelet packet so as to extract the best features and classify the features which are of different ideas by LVQ-ANN. Simulation result showed that the method proposed can provide a recognizable accuracy up to 92.7% in classification, it has come up to the standard for the practical application of BCI. References | Related Articles | Metrics

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Incremental learning of support vector machine based on hyperspheres Xu, Zhe (1); Mao, Zhi-Zhong (1) 2010, 31 (1):  16-19.  DOI: - Abstract ( 435 )   HTML   PDF (669KB) ( 1195 )   Support vector machine (SVM) has been successfully applied to solving classification and regression problems. However, to solve the quadratic programming problem is needed for SVM training process, and the more the number of training samples, the longer the training process. A novel incremental learning method was therefore proposed combining the hypershpere approach with regressional SVM to reduce the number of training samples by using two concentric hypershperes, thus shortening the training time. Analysis results showed that the incremental learning method has lower computational complexity than the normal SVM training method. Experimental results demonstrated that the method proposed can dramatically save the training time with negaligible degradation of regression accuracy. References | Related Articles | Metrics

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Comparison among three algorithms to solve unconstrained MLLS problems Han, Yi (1); Tang, Jia-Fu (1); Cai, Jian-Hu (2); Zhou, Gen-Gui (2) 2010, 31 (1):  20-22+27.  DOI: - Abstract ( 424 )   HTML   PDF (402KB) ( 621 )   To solve the unconstrained multilevel lot-sizing (UMLLS) problems, the harmonious particle swarm optimization (HPSO) algorithm, hybrid scatter search(HSS) algorithm and genetic algorithm integrated with repulsion operator (RGA) have been proposed. To study their suitability, a performance comparison among them was carried out systematically via a comprehensive test introducing the standard testing data sets, then the alternative of those algorithms can be decided for UMLLS problems with different sizes. The test results showed that HSS is more powerful for small/medium-sized problems and HPSO is superior to the other two algorithms in large-sized problems. References | Related Articles | Metrics

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Automated ranking of approximate query results of web database Meng, Xiang-Fu (1); Ma, Zong-Min (1); Zhang, Xiao-Yan (1) 2010, 31 (1):  23-27.  DOI: - Abstract ( 310 )   HTML   PDF (1880KB) ( 537 )   To solve the problem of over many results obtained from a Web database through an approximate query, an automated ranking method was first proposed for those results, taking advantages of the KL distance, PIR model and query history to formulate a tuple scoring function. According to the satisfiabilities of specified attribute values in result tuple to the initial query and the relevance of unspecified attribute values to users' preference, the scoring function evaluates the scores of ranked tuples. Experimental results demonstrated that the automated ranking method proposed can meet the users' requirements and their preference effectively with high efficiency. References | Related Articles | Metrics

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Improved addition of conic curve over the ring Zn Li, Guo-Jing (1); Li, Yong-Nan (1); Wen, Tao (1) 2010, 31 (1):  28-30.  DOI: - Abstract ( 283 )   HTML   PDF (970KB) ( 613 )   In conic curve cryptology, all the values of points in the operation of addition on conic curve over the ring Zn should be expressed in the (x, y) form as the criteria then what condition(C1, C2, C3 or O )the result of operation belongs to should be taken into consideration one by one, of which the computation is so tiresome. The operation of addition on conic curve of the ring is therefore to be improved in accordance to the definition of the addition on the ring Zn. It is proposed that the values of all points (x, y) on conic curve shall be expressed with the parameter t, and the (x, y) of all points are not required to work out in each and every step but the coordinates of the point P are to be decomposed according to the Chinese remainder theorem, i.e., incorporating the terms (tmp, tnq) to work out the coordinates of nP. Thus, during the operation of addition only the parameter t is needed so as to simplify such an operation of addition on conic curve over the ring Zn. As a result, the time required and computational complexity are both reduced obviously, which implies that the algorithm proposed is better than the operation of addition before the improvement. References | Related Articles | Metrics

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A compensation-supported substitution QoS model based on detailed transaction Yin, Ying (1); Zhang, Bin (1); Zhang, Xi-Zhe (1) 2010, 31 (1):  31-34.  DOI: - Abstract ( 246 )   HTML   PDF (281KB) ( 748 )   A QoS-substitution model with composition-supported is developed, since the traditional substitution models are unavailable due to lack of transactional support in the execution process of Web service. In the model, the interrelation between many kinds of services and characteristics of Web service for a certain business are all fully considered. Combining the composition cost for a failed or unavailable service with that to substitute the same one in the whole execution process of Web service, an objective QoS function is provided to evaluate comprehensively the composition-supported service that will be substituted. Then, a new QoS-driven service substitution algorithm supported by composition is proposed. Testing results demonstrated that the model proposed not only ensures the atomicity and data consistency in the service substitution process, but also improves the reliability and of service systems. References | Related Articles | Metrics

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Research on the fuzzy triangular localization model in WSNs Zhu, Jian (1); Zhao, Hai (1); Lin, Kai (1); Xu, Jiu-Qiang (1) 2010, 31 (1):  35-38.  DOI: - Abstract ( 272 )   HTML   PDF (1045KB) ( 618 )   Aiming at the shortages of range-based and range-free localization models such as low location precision, high latency/complexity and high-density nodes, a range-free localization model based on fuzzy recognition was developed where several swatch nodes were provided in location space. Then, combining the intensity of signal received in WSN with the fuzzy mathematics to acquire an unknown node's coordinate via computing the proximity degree between the unknown node and swatch nodes, the model developed can simplify the procedure to get coordinate solution. Verified by virtue of the simulation software NS-2 and analytic geometry, the fuzzy triangular localization model is proved of high performance. References | Related Articles | Metrics

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An improved MAP channel estimation for MIMO-OFDM systems Xu, Peng (1); Wang, Jin-Kuan (1); Qi, Feng (2) 2010, 31 (1):  39-42.  DOI: - Abstract ( 266 )   HTML   PDF (833KB) ( 709 )   A maximum a posteriori probability (MAP) algorithm was proposed for the multiple-input multiple-output with orthogonal frequency division multiplexing (MIMO-OFDM) systems, which reduces the computation complexity via the expectation maximum (EM) algorithm to decompose the MIMO channel estimation into a series of independent single-input/single-output(SISO) channel estimation. Besides, according to that the MIMO channels between sending and receiving antennae in an angle domain approximate to spatial independence, the most significant taps (MST) technique was employed to reduce the effect of noise on estimated performance. Simulation results indicated that the proposed algorithm gets lower estimation error at low SNR than conventional LS and EM algorithms. References | Related Articles | Metrics

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An ab-initio study of electron structure and micro-magnetism of Ni2MnIn alloy Huang, Zhen-Wei (1); Cai, Jun (2); Wang, Gang (1); Wang, Yan-Dong (1) 2010, 31 (1):  43-46.  DOI: - Abstract ( 291 )   HTML   PDF (685KB) ( 662 )   The electronic structure, magnetic moment, crystal structure parameters and characteristics of microscopic magnetism of Ni2MnIn Heusler alloy and tetragonal martensite(c/a=1.429) were studied theoretically via ab-initio pseudo-potential calculation based on density functional theory. Analyses of the bands, atomic magnetic moments and partial electron density of state (PDOS) showed that no obvious change is found in atomic orbital magnetic moment, unit cell's orbital magnetic moment and cell volume of each and every element in the Ni2MnIn Heusler alloy and tetragonal martensite; and the spin polarization is found in both phases as above. Calculated results showed that in the Ni2MnIn phase, the atomic orbital magnetic moment of Mn dominates the unit cell's magnetic moment, i.e., about 85% of the total magnetic moments of unit cells. The contribution of Ni to the total cell's magnetic moments is about 15%. As to the In atoms, they show a weak diamagnetism in both phases. In particular, the phase transformation of tetragonal martensite results in the decrease in Fermi energy of Ni2MnIn unit cells by 0.495eV. The theoretically calculated results were compared with other theoretic values. References | Related Articles | Metrics

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Low-temperature mechanical properties and microstructural stability of 18%Cr-12%Mn-0.55%N high-nitrogen austenitic stainless steel Xu, Ming-Zhou (1); Wang, Li-Jun (1); Wang, Jian-Jun (1); Liu, Chun-Ming (1) 2010, 31 (1):  47-50+55.  DOI: - Abstract ( 294 )   HTML   PDF (1603KB) ( 848 )   Mechanical behavior and microstructural stability of the high-nitrogen austenitic stainless steel 18%Cr-12%Mn-0.55%N at room/low temperature were investigated with its fracture mechanism discussed. Charpy impact test result showed that the ductile-brittle transformation of the steel specimens takes place at about -70°C and a cleavage-like fracture happens along the {111} facet of austenitic matrix. Furthermore, the tensile test result indicated that a deformation-induced phase transformation happens even at room temperature, from which the products include α' martensite and the other one whose structure and relevant parameters cannot be ascertained yet. Based on both the results, it is found that the steel has a good combination of high strength with favorable ductility when it is used at over -60°C. References | Related Articles | Metrics

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Mathematical modeling for dynamic recrystallization behavior of Low-Carbon 9Ni steels Xie, Zhang-Long (1); Liu, Zhen-Yu (1); Wang, Guo-Dong (1) 2010, 31 (1):  51-55.  DOI: - Abstract ( 340 )   HTML   PDF (943KB) ( 699 )   The dynamical recrystallization (DRX) behavior of 9Ni steel was investigated via a single-pass reduction test on a MMS-300 simulator over the temperatures range from 800 to 1150°C at the strain rates range from 0.05 to 1s-1. The critical conditions for DRX and peak stress/strain were determined by the relationship between work hardening rate (θ) and flow stress (σ). The material parameters in the hyperbolic sine constitutive equation were determined with regression analysis, and the DRX activation energy was thus obtained to be 269kJ/mol. The relationship between critical strain, peak strain/stress and the dimensionless parameter Z/A were established by linear regression. Mathematical model of the DRX kinetics was developed for low-carbon 9Ni steel by using Avrami equation and stress-strain curses. References | Related Articles | Metrics

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Properties of B4C ceramics prepared by pressureless sintering Yue, Xin-Yan (1); Ying, Wei-Feng (1); Yu, Liang (1); Ru, Hong-Qiang (1) 2010, 31 (1):  56-59.  DOI: - Abstract ( 308 )   HTML   PDF (810KB) ( 1329 )   The effect of SiC and C sintering aids on the mechanical properties of B4C ceramics prepared by pressureless sintering was investigated. Micro-powder B4C, SiC and C were used as starting materials. The results showed that the optimum sintering process is at 1975°C holding for 30min. The density, hardness and flexural strength all increase first then decrease with increasing SiC and C contents of which the optimal amount is 6% and 5%, respectively. The optimum bulk density, hardness, flexural strength and fracture toughness are 2.45g/cm3, 35GPa, 240MPa and 3.0MPa·m1/2, respectively. References | Related Articles | Metrics

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FEA numerical simulation for weight lightening design via carriage's stress of heavy-duty truck Wang, Xiao-Nan (1); Di, Hong-Shuang (1); Liang, Bing-Jie (1); Du, Lin-Xiu (1) 2010, 31 (1):  60-63.  DOI: - Abstract ( 406 )   HTML   PDF (1213KB) ( 894 )   To make the design weight of the carriage of heavy-duty truck lighter, the FEA software ANSYS was applied to the numerical simulation of the changes in structural strength and rigidity after using the 600MPa high-strength platform floor plate instead of the Q345B plate. The results showed that making the high-strength plate in different use under the action of 50t static load, the equivalent stress in the main longitudinal bearer is maximum, while that in the outer stringer and floor's cross reinforcements is less, with the minimum at the bottom/side/front/back plate. The 600MPa floor plate can meet the requirement for structural strength of which the margin is around 130MPa, and no margin can be found for Q345B plate. The maximum and minimum of total elastic displacement are found at the middle/upper part of side plate and the middle part of bottom plate, respectively, and, as a whole, the total elastic deformation of the carriage made from the 600MPa plate is greater than that made from Q345B because of the reduced structural rigidity due to decreased plate thickness. The simulation results have been applied in actual production, and the weight of truck's carriage is therefore reduced by about 21% with tonnage capability improved somewhat. A theoretical foundation is thus laid down for further investigation and practical production. References | Related Articles | Metrics

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Effects of traveling magnetic field on mixing behavior in RH refining process Geng, Dian-Qiao (1); Lei, Hong (1); He, Ji-Cheng (1) 2010, 31 (1):  64-67.  DOI: - Abstract ( 212 )   HTML   PDF (1426KB) ( 714 )   A mathematical model was developed to investigate the effect of traveling magnetic field with different exciting current parameters on the mixing behavior in RH degasser. The numerical results indicated that the mixing time decreases about linearly with increasing current intensity. The mixing time decreases first then increases with increasing current frequency and comes up to its minimum value at 30Hz. Applying the traveling magnetic field to the uptake or downtake when the exciting current intensity is 200A at 10Hz, the mixing time can be shortened by 9%~17%. With the operating conditions kept unchanged, shorter mixing time is available if applying the traveling magnetic field to the uptake instead of downtake, and the time can be shortened by 18%~26% if applying the magnetic field to both the uptake and downtake. Moreover, the mixing time decreases with increasing argon blowing flowrate, and the time comes down to its minimum value if the argon blowing flowrate is 1600NL/min. After the moment, the mixing time increases with argon blowing flowrate. References | Related Articles | Metrics

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Effects of low-frequency electromagnetic field on solidification process of conventional hot-top casting of 6063 aluminum alloy Wang, Xiang-Jie (1); Cui, Jian-Zhong (1); Jiang, Hui-Xue (1); Wang, Gao-Song (1) 2010, 31 (1):  68-71.  DOI: - Abstract ( 275 )   HTML   PDF (1431KB) ( 992 )   Low-frequency electromagnetic (LFE) field was applied to the conventional hot-top casting process, and thermocouples were used to measure the cooling process from different edge positions to the center of an ingot in the steady-state of casting process, thus getting the cooling curves and temperature distribution within the ingot. The effects of LFE field on the solidification process, macrostructure and thickness of surface segregation layer during the conventional hot-top casting of 6063 aluminum alloy were analyzed. The results showed that the forced convection resulting from Al melt in LFE field makes the temperature distribution more uniform to dissipate the overheat of Al melt so as to enable the temperature in the pool to be lower than the liquidus temperature of 6063 aluminum alloy and to increase the number of nucleating particles inside the pool, thus providing the fine and homogeneous macrostructure without any grain refiner added in and reducing the depth of liquidus cave. Heat transfer between ingot and mold is then intensified by the quickened flow velocity of Al melt. As a result, the initial solidifying point on the ingot surface in mold moves upwards to decrease the height of contact zone between the melt and mold so as to improve the surface quality of ingot. References | Related Articles | Metrics

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Effect of high-intensity magnetic field on precipitation treatment of Cu-20%Fe alloy Zuo, Xiao-Wei (1); Wang, En-Gang (1); Zhang, Lin (1); He, Ji-Cheng (1) 2010, 31 (1):  72-75.  DOI: - Abstract ( 427 )   HTML   PDF (1057KB) ( 766 )   Effect of high-intensity magnetic field on the microstructure evolution and solubility of Fe in Cu matrix of Cu-20wt%Fe alloy after precipitation treatment was investigated. The results showed that the spheroidization of Fe-rich dendrites slightly intensifies and their distribution is more uniform with the increasing magnetic induction of the high-intensity magnetic field exerted to the alloy. Observation by high-power SEM indicated that the Fe atoms precipitated from Cu matrix increases with increasing magnetic induction, which reveals that the magnetic field can stimulate the precipitation of Fe from the oversaturated Cu matrix. The solubility of Cu matrix in the Cu-20wt%Fe alloy specimens after precipitation treatment in different high-intensity magnetic field was analyzed by EDS methods, and the results showed that the solubility of Fe is minimum when the intensity of magnetic field is 10T at 500°C during precipitation. This is because of the effect combining high-intensity magnetic field with precipitating temperature. The former reduces the activation energy due to Fe atomic diffusion to stimulate the precipitation of Fe atoms, and the latter induces the dissolution of Fe atoms due to atomic diffusion. References | Related Articles | Metrics

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Preparation of calcium sulfate whiskers from desulphurized gypsum by hydrothermal synthesis Shi, Pei-Yang (1); Deng, Zhi-Yin (1); Yuan, Yi-Yi (1); Sun, Jun (1) 2010, 31 (1):  76-79.  DOI: - Abstract ( 548 )   HTML   PDF (1060KB) ( 1664 )   Hydrothermal synthesis was employed to prepare calcium sulfate whiskers (CSW) with desulphurized gypsum as raw material. The growth rules of CSW were investigated under different reaction conditions by virtue of chemical potential, electric conductivity, XRD and SEM. It was found that the aspect ratio of CSW tends to increase then decrease with increasing of the reaction temperature/time, solid-liquid ratio and initial pH value. The optimized process parameters as a result of the tests are the solid-liquid ratio is 1:10, initial pH value 5, raw material grain size 1.36μm and reaction temperature/time 140°C/120min, by which the aspect ratio of CSW may come up to 82.57. References | Related Articles | Metrics

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Calculation of radiative direct exchange areas using a reduced integration scheme Li, Guo-Jun (1); Chen, Hai-Geng (1); Yi, Zhi (1) 2010, 31 (1):  80-83.  DOI: - Abstract ( 305 )   HTML   PDF (639KB) ( 955 )   The definition of radiative direct-exchange areas(DEA) are usually involves four~sixfold integral in solution, and long-time computation is therefore unavoidable if using direct integral, thus restricting greatly the application of zone model. Then, the expressions of a reduced integration scheme are derived from conventional integral formulae to solve the radiative direct-exchange areas, and the Gaussian quadrature is introduced into the solutions to the radiative direct-exchange areas within 3-D closed system by either the reduced integration scheme or the direct integral. Compared with the result by direct integral, the result by reduced integration scheme not only satisfies well both the reciprocity and integrality as required by the radiative direct-exchange areas but also improves the computing accuracy with computing time shortened greatly. References | Related Articles | Metrics

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Effects of time for heat-treatment on properties of vanadium-doped titanium-bearing BF slag Xue, Xiang-Xin (1); Wang, Hui (1); Yang, He (1); Li, Shu-Xian (1) 2010, 31 (1):  84-87.  DOI: - Abstract ( 235 )   HTML   PDF (830KB) ( 706 )   Perovskite-type vanadium-doped titanium-bearing blast furnace slag (VTBBFS) photocatalyst was prepared by way of high-temperature solid phase method at 800°C with different time for heat-treatment and it was characterized by XRD, UV-vis absorption spectra and SEM. It was found that the VTBBFS photocatalyst is of perovskite type, and that there is no change found in the crystals structure and surface morphology of the photocatalysts because of different heat-treating time. But, the photoabsorbability of the photocatalyst is thus affected greatly, which enables the UV absorbability of the catalyst to be improved obviously with red shift found. Candida albicans was used as experimental bacterin to check the antifungal ability of VTBBFS photocatalyst. The results showed that VTBBFS photocatalyst has good resistance against Candida albicans if heat-treated for 2h, and its sterilizing rate will come up to 100% under common illumination with sustainable bacteriostasis provided. References | Related Articles | Metrics

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Pack boronizing of TC4 titanium alloy and kinetics of boronizing process Yi, Xiao-Hong (1); Fan, Zhan-Guo (1); Zhang, Jing-Lei (1); Li, Feng-Hua (1) 2010, 31 (1):  88-91+95.  DOI: - Abstract ( 383 )   HTML   PDF (1170KB) ( 781 )   Pack boronizing process was done on the surface of TC4(Ti-6Al-4V) alloy at 1000, 1050 and 1100°C, each was holding for 5, 10, 15 and 20h, separately. Then, the boronized layer thickness was tested and the curves of growing kinetics of the B-Ti compound layer were therefore given. Based on analyzing and fitting the test data with the software Sigma Plot 10.0, an isopach chart of boronzied layer was obtained. By XRD and SEM, the phase composition, microstructure and morphology of TC4 titanium alloy after boronizing were investigated. The results showed that the boronzied layer is composed of TiB2 and whiskerized TiB extending into matrix. Under such testing conditions, the layer thickness is in the range from 0.8 to 15μm. After a linear regression analysis, the average diffusive activation energy of boron in the TC4 titanium alloys is 65.23kJ/mol. References | Related Articles | Metrics

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Dissolution thermodynamics of CaO in CaCl2-CaO and equimolar CaCl2-NaCl-CaO Wang, Shu-Lan (1); Zhang, Fu-Sheng (1) 2010, 31 (1):  92-95.  DOI: - Abstract ( 314 )   HTML   PDF (828KB) ( 1393 )   In the temperature range from 923 to 1223K, the two-phase equilibrium relationships between solid CaO, molten CaCl2 and CaCl2-NaCl were estabilished seperately. The solubilities of CaO in CaCl2 and equimolar CaCl2-NaCl were measured by chemical method and, according to the rules of phase equilibrium, the activity coefficient, excess Gibbs free energy, enthalpy and entropy of CaO in the saturated CaO molten salts were calculated. In the temperature range from 1123 to 1223K, the solubility of CaO in CaCl2 is between 14% and 16%, i.e., higher than that in CaCl2-NaCl. The activity coefficient of CaO in molten CaCl2 is smaller than that in CaCl2-NaCl, i.e., CaCl2 attracts CaO more than what CaCl2-NaCl does. The behavior of CaCl2-CaO where CaO is saturated is close to regular solution. The relationships between the solubility and activity coefficient of CaO in molten salts and temperature are obtained through linear fitting. References | Related Articles | Metrics

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Dynamic analysis based on transfer matrix for vibration-compaction system Liu, Yang (1); Liu, Ting (1); Feng, Fei (1); Wen, Bang-Chun (1) 2010, 31 (1):  96-98+118.  DOI: - Abstract ( 223 )   HTML   PDF (338KB) ( 863 )   When the vibration-compaction system works, the materials used are deformed plastically under compaction, then the relationship between elastic resilience and displacement of the system presents nonlinearity and hysteresis. To study the dynamic characteristics of a vibration-compaction system, a 2-DOF model with piecewise curves and asymmetric hysteresis loop was developed, to which a solution introducing the transfer matrix was given. Describing what states every element is in mathematically in the model and analyzing all the data with simulation software, the results showed that the data thus obtained basically coincide with that computed by the transfer matrix equation, i.e., the transfer matrix model we developed approaches to actualities, thus providing an important reference for the dynamic analysis of relevant systems. References | Related Articles | Metrics

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Effect of the vibration coupling pumped concrete fluid with conveying pipes on concrete pump truck Guo, Da-Meng (1); Liu, Kuo (1); Xu, Da-Lu (1); Liu, Jie (1) 2010, 31 (1):  99-102.  DOI: - Abstract ( 254 )   HTML   PDF (2338KB) ( 659 )   The vibration coupling pumped concrete fluid with conveying pipes occurs typically in the concrete placing process of a concrete pump truck. A differential equation of motion was derived for the coupling, then a natural frequency curve during concrete conveying at different flowrates and under different fluid pressures was given via dimensionless discretization. It was revealed that the first-order and second-order natural frequencies both decrease with the increasing pumping-out pressure, and the natural frequency increases gradually with the increasing pumping-out speed of concrete. So, with the fluid pressure and concrete flowrate determined properly, the concrete placing process can be completed avoiding the operation in the range of resonance, thus reducing the fatigue damage to arm supports. The conclusions provide theoretically the reference for selecting the pumping-out pressure and speed especially the operating frequency of concrete pump. References | Related Articles | Metrics

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Integrated control study on testing system of solenoid valve Jiang, Yang (1); Liu, Hong-Yi (1); Tian, Hong-Hai (1); Cao, Yang (1) 2010, 31 (1):  103-106.  DOI: - Abstract ( 304 )   HTML   PDF (868KB) ( 949 )   In view of the features of such controlled parameters as pressure and flowrate and changeful test conditions including nonlinearity, time-varying uncertainty and certain hysteresis, an integrated control method was proposed for the testing system of solenoid valve. The mathematical models based on the testing system of the solenoid valve loop with oil as medium were developed, and the integrated intelligent control algorithm was introduced to implement the accurate control of parameters. An electro-hydraulic control simulation was done with the algorithm via Matlab/Simulink, and the results were analyzed comparatively to verify the effectiveness of the control algorithm. Then, the control algorithm was introduced into the test of solenoid valve, and an optimal integrated control strategy was determined for the system via comparative analysis. References | Related Articles | Metrics

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Inverted pendulum system control based on state observer and experimental investigation Luo, Zhong (1); Zhao, Shi-Xin (1); Shi, Zhi-Yong (1); Guo, Li-Xin (1) 2010, 31 (1):  107-110.  DOI: - Abstract ( 563 )   HTML   PDF (909KB) ( 1896 )   For the typical experiment system of nonlinear, strong coupling and multi-input/output control, a structural model of inverted pendulum system was set up with its working principle described. A controller design method based on state observer was proposed, and in the process of setting up the system model, the related basic parameters were measured experimentally on the vibrational mechanical principle of the pendulum system. The validity of the proposed control method was verified by experimental results, thus providing a theoretical basis and relevant method for the stable control and system design of an inverted pendulum system and other related system to be studied. References | Related Articles | Metrics

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Evaluation of abrasive layer optimization of grinding wheel and its surface topography after super high-speed point grinding Qiu, Jian (1); Gong, Ya-Dong (1); Liu, Chang-Fu (1); Zheng, Jing-Chao (2) 2010, 31 (1):  111-114.  DOI: - Abstract ( 244 )   HTML   PDF (1318KB) ( 784 )   Favorable grinding performance is available if the abrasive layer of point grinding wheel has an inclined dressing angle in the coarse grinding zone, by which a finer and smoother ground surface can be obtained in comparison to conventional abrasive layer. A method is therefore proposed to change the grinding wheel edge from parallel into inclined form so as to optimize the structure of abrasive layer. Combining the laser sensor with optical microscope to evaluate the topography of wheel surface, the correlations between the relevant parameters, grinding characteristics and grinding performance are investigated. It is found experimentally that the optimized abrasive layer is more suitable for grinding, and the abrasive grain distribution is uniform with very small fluctuation of heights of protruding grains, thus ensuring the high-quality ground surface. References | Related Articles | Metrics

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FEM numerical simulation of induction heating of chucking for electro-slag furnace Xia, Yong-Fa (1); Jin, Yu-Long (2) 2010, 31 (1):  115-118.  DOI: - Abstract ( 251 )   HTML   PDF (659KB) ( 589 )   A mathematical model was developed introducing the dual-vector magnetic potential into it for simulation of induction heating, based on FEM and the software ANSYS. Discusses the key technological problems and the ways to solve them, such as the coupling of temperature field with electromagnetic field in FEA and the dependence of physical parameters of workpiece materials on temperature. The induction heating process of the chucking for electro-slag furnace was analyzed to find out the temperature distribution of chucking and the variation of time-dependent temperature. The results showed that the maximum temperature is mainly concentrated on the surface layer of chucking and, what's more, the core part of chucking is basically unheated. Simulation results were verified in accordance to the practical application results on the whole. References | Related Articles | Metrics

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On the parameter recognition based on difference evolution algorithm for wall rock Qiu, Jing-Ping (1); Jiang, An-Nan (2); Xing, Jun (1); Sun, Xiao-Gang (1) 2010, 31 (1):  119-122.  DOI: - Abstract ( 254 )   HTML   PDF (679KB) ( 705 )   As a new intelligent optimizing algorithm, the difference evolution algorithm was introduced into the recognition of mine workings' wall rock parameters. Based on the orthogonal design and homogeneous design, a numerical test of drift driving was carried out to develop a regression model to reflect the relation between mechanical parameters and monitored tiny displacement of wall rock, with the difference between computed and monitored displacements as fit value, thus introducing the difference evolution algorithm to recognize relevant parameters. Discussing the principle of difference evolution algorithm and parameter recognizing steps, the algorithm was used to analyze the entry roadway of Jinshandian Iron Mine and the results indicated that the algorithm has rapidly global convergence which provides a new way to recognize the parameters of mine workings with high adaptability and good prospect in applications. References | Related Articles | Metrics

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Characteristics of gold mineral in Gengzhuang gold deposit and its significance to metallogeny Kou, Da-Ming (1); Huang, Fei (1); Yao, Yu-Zeng (1); Jin, Cheng-Zhu (1) 2010, 31 (1):  123-126.  DOI: - Abstract ( 261 )   HTML   PDF (646KB) ( 772 )   Based on earlier works, the genesis of gold deposits in Gengzhuang was studied in depth via systematical observations on the characteristics of the gold mineral . An assay was made for the composition of the mineral with an electron probe to determine the fineness of gold. It was found that in the minerals the electrum is the major part with small amount of natural gold and the fineness of gold mineral is 508~896 with an average assay 673. Observations on the shape and the size of the minerals indicated that the gold minerals are mainly in irregular brecciform and most of them are medium-grained or fine-grained, which are found mainly in the cracks and intracrystallines of sphalerite, pyrite, galena and other metallic sulphides. Combining the occurrence characteristics with ore-forming geological conditions, the forming conditions and ore genesis of Gengzhuang gold deposit are discussed, and it is revealed that the gold deposit experienced long-term metallogenic epoch and many genetic stages, i.e., the mesothermal-hypothermal ore-forming stages of which the hypothermal stage was dominant. The deposit is of hypabyssal or ultra-hypabyssal epithermal genesis. References | Related Articles | Metrics

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Experimental investigation on removing cadmium from electroplating wastewater by water-washing process with waste saccharomyces cerevisiae Dai, Shu-Juan (1); Wei, De-Zhou (1); Bai, Li-Mei (2); Cui, Bao-Yu (1) 2010, 31 (1):  127-131.  DOI: - Abstract ( 239 )   HTML   PDF (944KB) ( 722 )   The biosorption-sedimentation process for removing the heavy metal cadmium from electroplating wastewater was experimentally investigated taking the waste Saccharomyces cerevisiae as biosorbent on a self-making experimental setup. The results showed that biosorption rate and removed rate of Cd are 96.59% and 94.25% respectively on conditions that wastewater processed is 1L, Cd concentration in the wastewater about 26mg/L, pH value 7.0, the dose of the waste Saccharomyces cerevisiae 40g/L(in wet weight), at room temperature about 25°C, stiring speed 1000rpm, adsorbing time 30min and time for natural sedimentation 240min. The Cd concentration in wastewater after three-step biosorption comes up to china's national standard on effluents(&le0.1mg/L). With respect to the processing effect, the continuous process is relatively poorer than the intermittant one. The biosorption mechanism of the water-washing process with waste Saccharomyces cerevisiae for Cd removal was analyzed by SEM and EDS. The results showed that the cell structure of the bacteria used is destroyed in such a water-washing process, and the effects of chemical complexing and electrostatic adsorption are found in the biosorption process. References | Related Articles | Metrics

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Analysis of bending bearing capacity of the composite member of GFRP tube with RC column filled in Qin, Guo-Peng (1); Wang, Lian-Guang (1); Xia, Yu-Min (2) 2010, 31 (1):  132-135.  DOI: - Abstract ( 265 )   HTML   PDF (1654KB) ( 531 )   A GFRP tube in which a RC column is filled in is proposed as a new type of composite member. The member consists of an outer tube made of glass fiber reinforced polymer (GFRP), steel bars, and inner concrete. Bending tests were conducted with three specimens to investigate their flexural behavior. Based on the fiber model, a nonlinear analysis was programmed with the wall thickness of GFRP tube, concrete strength and percentage of reinforcement as principal parameters so as to calculate 9 members, thus obtaining the relevant relationship between bending moment and curvature. The results indicated that the bending bearing capacity of the composite members increases obviously with both the wall thickness of GFRP tube and concrete strength. The theory combining failure mechanism with the composite members was introduced separately to give a formula to calculate the bending bearing capacity of such members. Verifying test results showed that the calculation results agree well with test results. References | Related Articles | Metrics

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Uncertain multi-attribute sequential group decision-making process and its application to service innovation Xiang, Hui (1) 2010, 31 (1):  136-140.  DOI: - Abstract ( 263 )   HTML   PDF (189KB) ( 600 )   A new problem of uncertain multi-attribute sequential group decision-making process was put forward and investigated with the interval number. A combinational interval number weighted average operator was built taking account of both characteristics of linear and non-linear operators. Aiming at the dependence of comprehensive evaluation results during information aggregation on aggregating path, an idea of multipath aggregation based on deviation reduction was proposed to provide three synthesis methods, i.e., the deviation minimization, reliability weighting and objective differentiation with the methods applied to the selection of different strategies of service innovation which is a problem being widely concerned about theoretically and practically, the validity of the methods is verified. References | Related Articles | Metrics

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Monopoly firm's advertising investment analysis based on vertical differentiation Yuan, Wen-Bang (1); Zhao, Xin-Liang (1); Chen, Zhong-Quan (1) 2010, 31 (1):  141-144.  DOI: - Abstract ( 189 )   HTML   PDF (137KB) ( 583 )   A profit function of different ad intensity was derived within the framework of vertical product differentiation in accordance to the assumption of consumer's characteristic to reveal the ad models of firms with different goodwill. The ad models with different quality expectation coefficient were analyzed by the method of backward induction. The results showed that if the quality expectation coefficient is too small, the firms will choose not to pay the advertising, and if the coefficient is large enough, the high ad intensity will be the firms' choice, and if the coefficient is in the middle position, it's no difference for the firm to invest in high ad intensity and low ad intensity. The quality expectation coefficient relates so closely to the goodwill of firm that it can be regarded as the goodwill itself to a certain extent. A monopoly firm with better goodwill will provide high quality product to maintain its existing goodwill, which confirms further the conclusion that high-intensity ad signal high-quality. References | Related Articles | Metrics

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Location choice and motivation of agglomeration of home-country (region) FDI Zhang, Yan-Bo (1); Guo, Ya-Jun (1); Han, Ying (1) 2010, 31 (1):  145-148.  DOI: - Abstract ( 239 )   HTML   PDF (471KB) ( 661 )   FDI enterprises from the same source country agglomerated in a region in China, i.e., a geographical agglomeration, was a main trend in recent years. An oligopoly output competition model was therefore developed between FDI enterprises and host country enterprises, with a conjectural variable introduced to weigh up the cooperation level between relevant enterprises, thus analyzing the location choice behavior and motivation of the agglomeration of home-country FDI. It was found that the motivation mainly includes the reduction of cost and investment risk, China's governmental strategic policies and their powerful pulls, industrial traits of FDI and the cultural communication between host country and FDI source country. Aiming at the traits of regional agglomeration of home-country FDI, it is necessary to change the conventional idea about absorbing foreign investment and go on to the third-generation strategy for absorbing FDI. References | Related Articles | Metrics

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Operational efficiency evaluation of credit guarantee for SMEs Cui, Xiao-Ling (1); Zhong, Tian-Li (1); Qin, Jie (1) 2010, 31 (1):  149-152.  DOI: - Abstract ( 229 )   HTML   PDF (182KB) ( 568 )   Considering the profitability, risk sustainability and creditability of credit guarantee institution, a DEA-based efficiency evaluation was made to the composite operational efficiency including technical efficiency and scale efficiency of credit guarantee in a province of Northeast China with an empirical analysis made to the input redundancy and output deficiency. The results showed that most of the credit guarantees are in an inefficient state where although the technical efficiency is higher than the composite efficiency, it is purely not technical in fact. At present the credit guarantee is highly competent to take advantage managing techniques to decrease the input with the output level raised simultaneously, but most of credit guarantees are in a diseconomic scale state with both input redundancy and output deficiency. The fact implies that the credit guarantee cannot make its due contribution until the subsequent input is reasonable with corresponding output. References | Related Articles | Metrics