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15 February 2010, Volume 31 Issue 2 Previous Issue    Next Issue
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Robust stabilization of discrete singular systems with saturating actuators Yang, Dong-Mei (1); Xu, Yu-Ting (1); Sha, Cheng-Man (2) 2010, 31 (2):  153-156.  DOI: - Abstract ( 262 )   HTML   PDF (154KB) ( 482 )   Introducing the concept of saturation into the discrete singular systems, the robust stabilization of discrete singular systems with saturating actuators is discussed. Based on the sufficient and necessary conditions that the discrete singular system is admissible, a sufficient condition for the robust stability of the close-loop system is given via the generalized Lyapunov function and the linear matrix inequality. As a result, the design method of feedback controller is proposed taking advantage of the feasible solution of the linear matrix inequality, and a numerical example is given to demonstrate the effectiveness of the design method. References | Related Articles | Metrics

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On the flame propagation along pipeline during dust explosion between interconnected vessels Wang, Jian (1); Li, Xin-Guang (1); Zhong, Sheng-Jun (2); Wang, Fu-Li (1) 2010, 31 (2):  157-160.  DOI: - Abstract ( 417 )   HTML   PDF (426KB) ( 699 )   Combining experiments with numerical simulation, the flame propagation in two vessels was investigated during maize starch dust explosion, where the two vessels were interconnected with a pipeline. The explosion was ignited in one of vessels, then the flame propagated to the other one. The two-phase flow during explosion was modeled by the Eulerian-Lagrangian approach, where the well-known k-Ε model was introduced to simulate the turbulence of the gas phase with the EBU-Arrhenius model introduced to simulate the gas turbulent combustion. Such factors as the water vaporization, decomposition of volatile matters and the reactions of gas phases and reactions on particles' surfaces were all taken into account in the particles' combustion model. The operator split method and FCT algorithm were used to solve the mathematical models. Simulation showed the acceleration behavior of flame propagation, and the calculated results were proved well in conformity with measured ones. It means that the developed model is valuable for investigating the flame propagation mechanisms during dust explosion. References | Related Articles | Metrics

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Decision model and solution for logistic network system of multi-products with capacity constraints Zang, Jie (1); Tang, Jia-Fu (1) 2010, 31 (2):  161-164.  DOI: - Abstract ( 281 )   HTML   PDF (249KB) ( 758 )   Focusing on an integrated production-distribution system with multi-products, multi-manufacturers and multi-retailers, such problems as the production cycle of products, transportation frequencies in a cycle and the economic allocation among the manufacturers were investigated. Then, a decision model was developed, where the productive capacity of every manufacturer and that per unit products are taken as constraints with the minimum average total cost of a logistic network within a unit time as the objective to be optimized. In view of the nonlinear programming characteristics of the decision model, i. e., neither the convex nor the concave, a heuristic algorithm was proposed to approximately solve the model. Five instances at different sizes were calculated by the algorithm and the results were compared with the results by the quasi-Newton method. The comparison verified the correctness of the decision model and validity of the algorithm proposed. References | Related Articles | Metrics

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An analysis method based on correction of estimated value of β for fMRI at low field Yang, Ping (1); He, Yan-Fa (1); Wang, Jin-Xing (1); Yu, Bing (2) 2010, 31 (2):  165-167+171.  DOI: - Abstract ( 322 )   HTML   PDF (377KB) ( 737 )   Proposes an effective analysis method to decrease the interference effect of non-brain signals on the functional magnetic resonance imaging (fMRI) at low field, by which the activated area of the brain can be located precisely. The method combines the image segment method based on a deformable surface model with the voxel-based morphometry (VBM). The extracted brain tissue is taken as an explicit mask. Then, an analysis mask is constructed to correct the estimated value of the parameter β in general linear model (GLM), thus making the statistical inference just available to the brain tissue. The practical application revealed that the method proposed can effectively eliminate the pseudo-activated area generated by the changes of the signals from background, skull and scalp and improve the reliability and precision of fMRI at low field. References | Related Articles | Metrics

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Study on analysis model of HMM-Based WSN prior event Li, Chuan-Wen (1); Gu, Yu (1); Li, Fang-Fang (1); Yu, Ge (1) 2010, 31 (2):  168-171.  DOI: - Abstract ( 343 )   HTML   PDF (1282KB) ( 600 )   To make full use of the effective data produced from simulation process, the hidden Markov model is applied to identifying the status of simulated sensor nodes. Taking account of the characteristics of WSN (wireless sensor network), the Baum-Welch algorithm is extended to design a complex event recognition algorithm that is discussed in detail for the state constraints and the way to process the observation window. Such key problems as data acquisition, state modeling and hidden-state inference in the event recognition algorithm are analyzed in depth, with the temporal and spatial complexities of the algorithm explained. A WSN simulation platform is therefore designed and implemented to verify the effectiveness of the algorithm and the practicality of the system. References | Related Articles | Metrics

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Automated categorization of web database query results Meng, Xiang-Fu (1); Ma, Zong-Min (1); Yan, Li (1); Zhang, Fu (1) 2010, 31 (2):  172-176.  DOI: - Abstract ( 226 )   HTML   PDF (365KB) ( 679 )   To deal with the problem of too many results obtained from a Web database in response to a user query, a novel approach is proposed to categorize the Web database query results automatically, i.e., to generate a labeled, hierarchical navigational tree dynamically over the query results. The hierarchy of the tree includes two processing steps. At the first step, the query histories of all users in the system are analyzed offline to cluster the similar queries semantically, then the original data are divided into multiple tuple clusters in accordance to the clustered queries, among which each tuple cluster corresponds to a certain type of user preferences. When a user queries about something, at the online step, a navigational tree over the clusters generated at the first step is provided for the user to enable him to select and locate the information he needs easier. Experimental results revealed that the categorization approach proposed can meet the user's personalized requirements effectively. References | Related Articles | Metrics

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Distributed Top-k query algorithm based on uncertain data Wang, Shuang (1); Wang, Guo-Ren (2) 2010, 31 (2):  177-180.  DOI: - Abstract ( 267 )   HTML   PDF (361KB) ( 698 )   Top-k query based on uncertain data has quickly attracted a lot of interested users, however, none of them has addressed himself to that the algorithm works in a distributed setting. A distributed Top-k algorithm based on uncertain data(UDTopk) is therefore presented to save the communication bandwidths. A data structure called candidate set is designed and proposed, where only the minimum amount of data is contained and the tuples that have been removed from the set will not affect the answer to a Top-k query. This algorithm presented can be dynamically maintained with new tuples being added, and only small amount of data is required to transmit, thus reducing the data transmission in the network. The experimental results showed that the UDTopk algorithm can effectively reduce the communication cost. References | Related Articles | Metrics

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Internet AS-level topological community characteristics and evolution Ge, Xin (1); Zhao, Hai (1); Ai, Jun (1); Fu, Da-Yu (2) 2010, 31 (2):  181-184.  DOI: - Abstract ( 262 )   HTML   PDF (938KB) ( 765 )   Taking the mass topological data at the Internet AS (autonomous system) level provided by CAIDA as sample data, the sample coverage and prejudice in sampling are discussed to correct the sample data. Then, the topological data at the Internet AS level from 2001 to 2007 are divided into different communities, and the eigenvalues relevant to community evolution are calculated, such as the modularity and community size. The results showed that the topological data at the Internet AS level exhibit more and more apparent characteristics of community gradually. Simultaneously, the dynamical behavior of the nodes in the AS domain is analyzed according to the eigenvalues relevant to community evolution, and what causes the evolution is analyzed as well. References | Related Articles | Metrics

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A management protocol of SON-oriented self-organizing behavior Wang, Xing-Wei (1); Li, Xue-Jiao (1); Huang, Min (1) 2010, 31 (2):  185-188.  DOI: - Abstract ( 264 )   HTML   PDF (192KB) ( 546 )   Based on the link status routing protocol OSPFv3, a management protocol for SON (self-organizing networks)-oriented self-organizing behavior is proposed to support various biological behavior of nodes, such as incarnation, cognition of surroundings, relationship establishment/deletion, migration, cloning, dormancy, analepsia, being awakened and death. Its prototype system was implemented via utilizing the Quagga software router and modifying the OSPFv3 module in it. Then, its performance evaluation was done through video conference/broadcasting on a network platform referring to the topology CERNET2. The results showed that the proposed protocol is feasible and effective. References | Related Articles | Metrics

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Analysis and improvement of a group signature scheme Liu, Dan-Ni (1); Wang, Xing-Wei (1); Guo, Lei (1); Huang, Min (1) 2010, 31 (2):  189-192+213.  DOI: - Abstract ( 213 )   HTML   PDF (280KB) ( 701 )   Based on Chinese remainder theorem, an improved signature scheme is proposed to strictly verify the validity of the parameters transferring between the applicant and group center when a person is applying for joining the group, prevent the information from interpolation and ensure that no impostor can join the group. Then the information on a candidate even impostor is impossible to be included in the signatures, thus providing the irrelevance among all signatures. When deleting a group member, the scheme will restrict the modifications to be made to the public key of the member so as to ensure that no way will the member sign. The proposed scheme solves the problem as shown in Wang's scheme, such as divulging private key, signature relevance, forgery attack of revoked member and invalid join. Analyzed results showed that the proposed scheme can meet the security for the group signature. References | Related Articles | Metrics

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On the adaptive preemption algorithm in DS-TE networks Du, Li (1); Li, Hai-Tao (1) 2010, 31 (2):  193-196.  DOI: - Abstract ( 226 )   HTML   PDF (512KB) ( 594 )   In the DS-TE networks the preemption provides the high priority business with reliable service quality, and it will be more effective especially when a network overload or node and link failure occurs. An adaptive preemption algorithm is therefore proposed to adapt to the bandwidth demand for new LSP by strengthening the control of the LSR over LSP resources. To avoid the setting of parameters, the adaptive preemption algorithm is divided into A-minconn and A-minpri. Simulation results showed that the adaptive preemption algorithm is obviously superior to the conventional algorithm in the preemption performance including bandwidth, priority and the numbers required. References | Related Articles | Metrics

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Design and verification of the NSIS-based network management signaling protocol Wen, Ying-You (1); Chen, Shu-Yi (1); Li, Jia (1); Zhao, Hong (1) 2010, 31 (2):  197-201.  DOI: - Abstract ( 258 )   HTML   PDF (643KB) ( 850 )   An NSIS-based extendable network management protocol is proposed, of which the service primitives and data units are defined to implement the main communication process and management operation procedure of the protocol. The proposed protocol are described and formatted with Petri nets, with the logic correctness and performance of the protocol verified. The results of simulation with NS-2 for the whole protocol and relevant verification showed that the NSIS-based network management protocol has not only the IP flexibility, but also the high efficiency of signaling, thus ensuring the safe and reliable transmission of management information to fulfill the requirements for new-generation network management of the IP-based multi-service network. References | Related Articles | Metrics

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Investigation on hot deformation behavior and mathematical models of flow stress of Q420 HSLA steel Li, Jing (1); Zhao, De-Wen (1); Liu, Xiang-Hua (1) 2010, 31 (2):  202-206.  DOI: - Abstract ( 380 )   HTML   PDF (896KB) ( 1031 )   The effect of deformation conditions on dynamic recrystallization behavior of Nb-V microalloyed HSLA steel was investigated via high-temperature single pass reduction tests on a Gleeble-2000 thermomechanical simulator, with some mathematical models developed for flow stress during hot deformation. It was found that the dynamic recrystallization occurs only at higher temperature and lower strain rate, and the peak strain/stress, steady strain and critical stress are all in linear relationship with lnZ. The prediction models developed for flow stress indicated that they are in good agreement with experimental results. References | Related Articles | Metrics

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Application of similarity principle to cold simulation of granulation of steel slag Zhang, Yu-Zhu (1); Long, Yue (1); Wang, Shao-Ning (2); Xing, Hong-Wei (2) 2010, 31 (2):  207-209.  DOI: - Abstract ( 215 )   HTML   PDF (170KB) ( 632 )   With the molten paraffin applied to simulating the cold air quenching for the granulation of liquid steel slag in lab, the effects of gas pressure, airflow velocity, gas flowrates and liquid steel slag flow and its vertical falling distance on the granulation were investigated. The results showed that after the granulation the distribution of paraffin grain size is in inverse proportion to the gas pressure/flowrates and airflow velocity. Based on the similarity principle and dimensional analysis, the criterion was given correspondingly. Then the air quenched paraffin and granulation was calculated and the results revealed that the grain size of granulated steel slag is relatively even and all grain sizes are less than 3 mm if the gas pressure p=0.56 MPa, airflow velocity v=93.33 m/s, vertical falling distance l=18.7 cm, and gas flowrate Q=338 m3/h. The parameters as above are available to the in-situ granulation of liquid steel slag for reference. References | Related Articles | Metrics

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Effect of roasting on chlorine content in powdered CaB6 prepared by self-propagating high-temperature synthesis Dou, Zhi-He (1); Zhang, Ting-An (1); Niu, Li-Ping (1); He, Ji-Cheng (1) 2010, 31 (2):  210-213.  DOI: - Abstract ( 240 )   HTML   PDF (536KB) ( 629 )   To discuss the effects of roasting temperature/time on the Cl content in powder CaB6 synthesized by SHS(self-propagating high-temperature synthesis) process, the CaB6 was characterized by DSC, XRD and SEM. The results indicated that the products from SHS include CaB6, MgO and little of both Ca3(BO3)2 and Mg3(BO3)2, and the leached product is so pure that the mass fraction of CaB6 is 96.82wt%, and the residue Cl content in CaB6 is only 0.36%. The removal rate of Cl from CaB6 increases with the roasting temperature/time increasing, e.g., the removal rate of Cl can be up to 80.12% after roasting CaB6 for 6hr at 720°C. However, over temperature will degrade CaB6 due to oxidation with decreasing removal rate of Cl. References | Related Articles | Metrics

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Effect of titanium on solidification and segregation of DZ68 alloy Guan, Xiu-Rong (1); Zheng, Zhi (2); Liu, En-Ze (2); Zhai, Yu-Chun (1) 2010, 31 (2):  214-216+220.  DOI: - Abstract ( 296 )   HTML   PDF (244KB) ( 614 )   Solidification and segregation of the major elements in DZ68 alloy with different Ti contents were studied by optical microscopy (OM) and electronic probe micro analysis (EPMA). The results showed that both the temperature of initial solidification and temperature of final solidification decrease gradually but the temperature range of solidification increases gradually with increasing Ti content in alloy under the test conditions. However, the increasing Ti content enhances both the positive segregation of Ta and negative segregation of W obviously. To reduce the (γ+γ′) eutectic in DZ68 alloy, the mass fraction of Ti in alloy should not be more than 1.7%. References | Related Articles | Metrics

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Theoretical study on fullerene C80′s derivatives C80X12(X=H, F, Cl, Br) Shen, Hong-Tao (1); Wang, Dong-Lai (2); Sun, Xiao-Ping (2); Zhai, Yu-Chun (1) 2010, 31 (2):  217-220.  DOI: - Abstract ( 249 )   HTML   PDF (902KB) ( 571 )   Based on the B3LYP density functional theory, the equilibrium geometrics, electronic structures and vibration frequencies of the C80 fullerene and its derivatives C80X12(X=H, F, Cl, Br) were studied using 6-31G* basis set to theoretically predict the stability of C80X12. The geometry, total energy, frontier orbital energy gap and the heat of reaction of these derivatives were presented. The calculated results indicated that all the four structures as above are the stationary points on the potential energy surface of C80X12(X=H, F, Cl, Br) molecules, and the LUMO-HOMO gap energy of C80X12 are higher than C80 and all of these addition reactions are exothermic. Therefore, it is quite possible to synthesize the C80X12 experimentally. References | Related Articles | Metrics

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Foaming parameters and quasi-static compressibility of Al foams made by PM route Wang, Lei (1); Yao, Guang-Chun (1); Zhang, Xiao-Ming (1); Zu, Guo-Yin (1) 2010, 31 (2):  221-224.  DOI: - Abstract ( 295 )   HTML   PDF (1229KB) ( 726 )   Aluminum (Al) foams with different apparent densities were prepared successfully by powder metallurgy (PM) route. The effects of foaming process parameters on cell structures and expansion behavior were discussed in detail. The results showed that the temperature variation of foamable precursors is divided into three phases, i.e., linearly quick rising, constant and quick cooling, and the choice of furnace temperature depends on the linearly quick rising. The optimum foaming time and expansion rate are 120 sec and 434%, respectively, through the comparison of the cell structures and expansion behavior at different foaming times. Preheating precursors does not affect their temperature rising rates obviously but shortens the foaming time. The results of quasi-static compressibility tests showed that no obvious stress fluctuation is found during the collapse process of Al foams and the compressive strength, elastic modulus and compact stress all increase with apparent density. References | Related Articles | Metrics

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Coating Al2O3 on short graphite fibers by sol-gel method Hua, Zhong-Sheng (1); Yao, Guang-Chun (1); Ma, Jia (1); Wang, Lei (1) 2010, 31 (2):  225-227+240.  DOI: - Abstract ( 278 )   HTML   PDF (447KB) ( 746 )   Taking the aluminium isopropoxide as starting material, the Al2O3 coating about 1~2 μm thick was successfully deposited on short graphite fibers by a sol-gel method. The appropriate process conditions for the Al2O3 coating were obtained, i.e., pH value is 6, concentration of boehmite sol 0.4 mol/L and coating time 16 hr. The coating was characterized by XRD and SEM, and the results showed that the coating is pure with thickness uniformly distributed, and bonded closely to the surfaces of graphite fibers. The results of antioxidation test indicated that the antioxidability of graphite fibers is improved obviously after coating Al2O3. References | Related Articles | Metrics

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Polysaccharide extraction from extracellular polymeric substance via bioleaching Fu, Yao (1); Yang, Hong-Ying (1); Tong, Lin-Lin (1); Zhang, Chang-Zheng (1) 2010, 31 (2):  228-231.  DOI: - Abstract ( 280 )   HTML   PDF (469KB) ( 778 )   With the EDTA (ethylene diamine tetraacetic acid) and H2SO4 (sulfuric acid) solutions both used as the extractants to extract the polysaccharide from EPS (extracellular polymeric substance) via bioleaching, the extracting process includes four steps, i.e., collecting thallus by centrifugation, leaching polysaccharide with extractants, separating polysaccharide by centrifugation and filtering out thallus. The extracted polysaccharide content was measured by phenol-sulfuric acid. The results showed that the extractant EDTA is superior to H2SO4 in extraction effect if their mass fractions are the same, and the 3% EDTA is regarded as the best one in our tests, by which the content of extracted polysaccharide can be up to 0.017 mg·mL-1. The whole extracting process has the advantages of simple reagent required, easy to operate and less interfering factors. References | Related Articles | Metrics

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Synthesis and surface modification of NaYF4:Yb, Er upconversion fluorescent nanoparticles Wang, Meng (1); Liu, Jin-Ling (1); Mi, Cong-Cong (1); Xu, Shu-Kun (1) 2010, 31 (2):  232-235.  DOI: - Abstract ( 588 )   HTML   PDF (344KB) ( 1010 )   NaYF4:Yb, Er upconversion nanoparticles with strong fluorescent intensity were synthesized in the liquid paraffin-oleic acid system via a thermolysis method, with the rare earth stearate used as precursor. The as-prepared nanoparticles were characterized by TEM, XRD, FT-IR and luminescence spectroscopy. It was inferred that the mechanism of the synthesis is of a solid-liquid two-phase reaction. The effects of reaction time, temperature and solvent composition on the fluorescent performance of the nanoparticles were discussed in detail. As a result, the oleic acid-coated hydrophobic nanoparticles became highly hydrophilic after their surfaces were modified with carboxylic groups by use of the Lemieux-von Rudloff reagent. References | Related Articles | Metrics

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Effects of polymer-cement ratio and water-cement ratio on properties and microstructure of modified mortars Zhao, Wen-Jie (1); Zhang, Hui-Xuan (2); Zhang, Bao-Yan (1) 2010, 31 (2):  236-240.  DOI: - Abstract ( 363 )   HTML   PDF (643KB) ( 1160 )   The polybutadiene-graft-polystyrene (PB-g-PS) latex with a core-shell ratio 50/50 was used to modify cement mortar. The effects of water-cement ratio (W/C) and the polymer-cement ratio (P/C) on the flowability, compressive/flexural strength and water absorption rate of the cement mortar modified with PB-g-PS core-shell structure latex were investigated. Experimental results showed that the flowability of modified mortar increases with increasing P/C and W/C, and the PB-g-PS latex can remarkably reduce the capillary water absorption rate. Although the compressive strength of the PMM (polymer modified mortar) decreases, the flexural strength of part of PMMs increases to a certain extent at low W/C. The microstructural analysis showed that the mortar modified in such way is of more compact structure, thus benefitting the improvement of its performance. References | Related Articles | Metrics

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Comprehensive fuzzy evaluation for generalized product quality based on entropy weight Chen, Ya-Zhe (1); Liu, Gui-Zhen (1); Liu, Ting (1); Wen, Bang-Chun (1) 2010, 31 (2):  241-244.  DOI: - Abstract ( 262 )   HTML   PDF (445KB) ( 999 )   With a view to improving product quality, the concept of generalized product quality is proposed and analyzed in depth to frame a comprehensive fuzzy evaluation system for product quality, which includes all the constructional, operational and technological performance and functions and takes account of the hierarchy and complexity of such an evaluation system. In the system the weighted value for each and every evaluation index is determined by combining the entropy weight with subjective weight so as to make the evaluation more objective and scientific. Compared with the method of comprehensive fuzzy evaluation, the evaluation system thus framed gets rid of the empirical subjectivity in determining index weight, thus enhancing the dependability of the weight and, as a result, such an evaluation will be more reliable. References | Related Articles | Metrics

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Experiment-based analysis of dynamical characteristics of giant magnetostrictive actuator Li, Dong (1); Yuan, Hui-Qun (2) 2010, 31 (2):  245-248+288.  DOI: - Abstract ( 261 )   HTML   PDF (625KB) ( 617 )   Based on the relationship between the exciting current, axial position of giant magnetostrictive material and magnetic field intensity, which was obtained from the experiment of giant magnetostrictive actuator(GMA), the theoretical formula between the current along the axis of the coil around the thick-wall hollow column and magnetic field intensity was corrected. With the corrected formula used, the dynamical model of GMA was analyzed theoretically to get the vibration responses of GMA. Then, the effects of correction factors, bias magnetic field and pre-compression stress on GMA were discussed. The results indicated that the correction factors affect the dynamical characteristics of GMA greatly, e.g., if the correction factor K′=1.24, the hysteresis loops between output displacement and input exciting current that obtained by the experimental fitting function and the theoretical formula as above match perfectly. The vibration responses of GMA have distinct nonlinear characteristics and they are affected greatly by correction factors. Meanwhile, the bias magnetic field and pre-compression stress have distinct influence on amplitude-frequency characteristics of GMA. References | Related Articles | Metrics

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Reliability model considering statistic method of loading Gao, Peng (1); Xie, Li-Yang (1) 2010, 31 (2):  249-252.  DOI: - Abstract ( 280 )   HTML   PDF (223KB) ( 539 )   Analyzing the statistical methods of probability density function of loading, the relevant transverse and longitudinal load distributions are defined with the reliability models proposed. Because the transverse distribution is usually obtained easily, the relationship between reliability of a part and loading frequency is emphatically studied when the transverse distribution is known, then a model is developed to calculate reliability. In addition, assuming that the loading process is a Poisson process, the relationship between reliability and service time is analyzed considering strength degradation and using the equivalent loading. The results show that for the same probability density function of loading there are some quite different values of reliability if using different statistical methods. Therefore, the reliability model should be chosen correspondingly according to the statistical method to be used. References | Related Articles | Metrics

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A virtual test based on Reynolds equation for reliability of sliding bearings Chen, Peng-Fei (1); Sun, Zhi-Li (1); Yuan, Zhe (1) 2010, 31 (2):  253-256.  DOI: - Abstract ( 318 )   HTML   PDF (370KB) ( 663 )   A virtual test of reliability was proposed to solve the wear-out failure problem of the main sliding bearing of reciprocating compressor. Equivalent stiffness was deduced from the Reynolds equation of hydrodynamic lubrication with the equivalent elastic modulus given according to Hooke law. The nonlinear FEA software ANSYS/LS-DYNA was used to develop the models of virtual prototype with the shell elements used to simulate oil film. The whole process of simulation was compiled to be a Macro program by the ANSYS parametric design language (APDL). Test sampling points of random variables were designed by central composite method and the Macro program was modified to implement the random sampling of virtual prototype. Then, the dynamic simulation was done for each and every sampling result of the prototype to get the output response data, i.e., the specific pressure of oil film. According to the response surface and testing data, an ultimate state equation was given to analyze both the reliability and sensitivity, thus providing a reference for the design of sliding bearings theoretically. References | Related Articles | Metrics

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Application of Gabor filter to strip surface defect detection Cong, Jia-Hui (1); Yan, Yun-Hui (1); Dong, De-Wei (1) 2010, 31 (2):  257-260.  DOI: - Abstract ( 374 )   HTML   PDF (1299KB) ( 981 )   The Gabor filter was applied to the strip surface defect detection because of its selectivity of frequency and direction. In addition to its denoisability, the detection system can keep the images of textural characteristics of defects completely. With the evaluation function introduced in, the difference between energy responses from both defective and non-defective images was maximized to determine the optimum parameter setting of the filter. Based on the optimum threshold function, the binarized images were obtained and the low-level noises involved in those images were removed by morphological analysis method, thus providing the segmented defective images. Experimental results verified the effectiveness of the method proposed. References | Related Articles | Metrics

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Assembly sequence planning based on particle swarm optimization algorithm for complex product Yu, Hong (1); Wang, Cheng-En (2); Yu, Jia-Peng (2); Yuan, Hui (2) 2010, 31 (2):  261-264.  DOI: - Abstract ( 430 )   HTML   PDF (1277KB) ( 853 )   According to the characteristics and demands of assembly sequence planning (ASP) of complex products, the particle swarm optimization (PSO) algorithm, which is used mainly to optimize the spatial continuity, is extended to solve the ASP problem. The algorithm redefines the particle's position, velocity and relevant operations in sequencing space in accordance to the characteristics of solution. To rise above the deficiency that PSO algorithm is easy to fall into local optimization, a new learning mechanism is taken up to improve the optimizability of the algorithm. Based on the interference matrixes, connection matrix and support matrix, the geometrical feasibility, assembly stability and the occurrence of changing the assembly direction are all taken into account as the evaluation indices to form an objective function. The validity and feasibility of the proposed algorithm have been verified via exemplification. References | Related Articles | Metrics

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Change feature of infrared radiation from loaded damp rock Liu, Shan-Jun (1); Wu, Li-Xin (1); Zhang, Yan-Bo (3); Chen, Qun-Long (3) 2010, 31 (2):  265-268.  DOI: - Abstract ( 344 )   HTML   PDF (450KB) ( 643 )   The infrared radiation from dry sandstone and damp sandstone in the process of uniaxial compression was detected by means of infrared thermal imager. It was revealed that the average infrared radiation temperature (AIRT) of damp rock increases with loading and keeps its change in step with the stress, and that the fluctuation of AIRT is much less. The AIRT increment of damp rock is higher than that of dry rock under unit load before destabilization and the fact shows that water will intensify the infrared radiation from loaded rock, but no obvious change was found on thermal image during the instantaneous fracture of damp rock. The relation between the AIRT and stress in dry rock is not simply in corresponding state like damp rock, but the obvious AIRT rise and change of thermal images of dry rock were found during instantaneous fracture. It's possible to monitor the rock stress of damp rock via the change synchronization between AIRT and stress, and to analyze the spatial position and mode of the catastrophe by making use of the change of thermal images during instantaneous fracture of dry rock. References | Related Articles | Metrics

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A method of economic analysis to determine mineral processing performance indexes Zhang, Zhi-Jun (1); Liu, Jiong-Tian (1); Feng, Li (2) 2010, 31 (2):  269-272.  DOI: - Abstract ( 303 )   HTML   PDF (1615KB) ( 513 )   An economic optimization-oriented method of analysis was proposed to determine the optimal output rate and grade of flotation concentrate from a certain hematite mine, thus maximizing the economic benefit. With the NaOH, starch, CaO and RA515 used as reverse flotation agents and lots of flotation tests done, the allowable ranges of dose of different agents were determined, then a regression model was developed through orthogonal tests to determine the concentrate grade, output rate and dose of various agents for flotation. According to the relation between price and concentrate grade, an optimization model was developed and, as a result, the proposed method was used to determine the appropriate concentrate grade and output value, i.e., 61.95% and 61.19%, respectively, by which the max. income per 100 t raw ore came up to RMB 69 thousand yuan. Exemplification result showed that the method proposed is simple and practical. References | Related Articles | Metrics

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On tolerability of photosynthetic bacteria for p-chloroaniline Li, Liang (1); Hu, Xiao-Min (1); Dong, Yi-Hua (1); Zheng, Ling-Zi (1) 2010, 31 (2):  273-276.  DOI: - Abstract ( 397 )   HTML   PDF (321KB) ( 710 )   A strain of purple non-sulfur bacteria (PNSB) named CS2 was screened from the sediment near the sewage outfall in Benxi Steel Coking Plant. As a photosynthetic strain, CS2 can degrade the p-chloroaniline (PCA) with high efficiency. The effects of concentration of PCA on cell growth and dehydrogenase activity of original/domesticated CS2 strains were investigated. Experimental results showed that with the increasing PCA concentration the growth and dehydrogenase activity of original bacteria are obviously inhabited. However, the tolerability of domesticated CS2 strain for PCA is dramatically improved. The results of a standard method of aquatic bioassay for the toxicity evaluation of chemicals applied in the experiments showed that the lowest observed effects of concentration (LOEC) of the original/domesticated CS2 strain growth are 60 mg/L and 100 mg/L, respectively. On the contrary, the half-inhibitory concentration (IC50) of PCA for the inhibition of original/domesticated CS2 strain growth are 162.5 mg/L and 423.9 mg/L, respectively, i.e., higher than many kinds of bacteria as reported previously. References | Related Articles | Metrics

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Predicting settlement under gas pressure in bioreactor landfills Sun, Hong-Jun (1); Liang, Li (1); Zhao, Li-Hong (2); Wang, Xue-Zhi (2) 2010, 31 (2):  277-280.  DOI: - Abstract ( 255 )   HTML   PDF (948KB) ( 736 )   To study the influence of gas pressure on the bioreactor landfill settlement, the bioreactor landfill is simplified as a one-dimensional gas seepage field. Incorporating Darcy's law, ideal gas law, the principle of effective stress and the theory of fluid dynamics in porous media, it is assumed that the bioreactor landfill leachate can fully infuse circularly into the wastes. Then, based on the conservation of gas mass, a mathematical model is developed for the settlement under the action of gas pressure in a bioreactor landfill according to the relationship between the air pressure difference between atmosphere and piled wastes in landfill and landfill settlement during gas dissipation. A finite difference method is used to solve the model. With an exemplification, the model is verified available to predict well the bioreactor landfill settlement. References | Related Articles | Metrics

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Slip calculation of corroded prestressed steel reinforced concrete under uniformly distributed load Ha, Na (1); Wang, Lian-Guang (1); Wang, Wen-Hao (2) 2010, 31 (2):  281-284.  DOI: - Abstract ( 259 )   HTML   PDF (1681KB) ( 487 )   Based on the theory of elasticity in combination with the loading conditions for a prestressed steel reinforced concrete beam, the differential equations are given to theoretically calculate the relative slip between the surfaces of concrete and corroded steel under uniformly distributed load, where the prestressed increment and corrosion rates of both steel and bars are all taken into account. Discusses the influences of the corrosion rates, loading and prestressed increment on the relative slip, thus giving the simplified slip calculation formulae. Calculated results showed that the slip increases with corrosion rate of steel and loading, but the corrosion rates of bars and prestressed increment affect the slip nonobviously. References | Related Articles | Metrics

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Research on concrete hydration heat in raft foundation and numerical simulation Wu, Xian (1); Mu, Chun-Long (1); Zhang, Li-Li (2); Wang, Cheng (1) 2010, 31 (2):  285-288.  DOI: - Abstract ( 367 )   HTML   PDF (1104KB) ( 897 )   Starting from an actual high-rise building project, the temperature field formed by the hydration heat in a 28-day concrete curing period after concrete placing was discussed, as well as the calculation relevant to it. The FEA software ANSYS was used for the thermal analysis of the temperature field formed by the bulky concrete of the raft foundation required for high-rise buildings. The temperature distribution of the raft foundation in the 28-day concrete curing period was calculated preliminarily through numerical simulation. Then, the temperature field calculated for prediction was given to evaluate the trend of temperature-induced cracking, by which a temperature-fall technology in foundation construction can be formulated reasonably. References | Related Articles | Metrics

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A method to choose the hospital-based emergency medical service Jiang, Yan-Ping (1); Wang, Ya (1); Liang, Hai-Ming (1) 2010, 31 (2):  289-292.  DOI: - Abstract ( 238 )   HTML   PDF (148KB) ( 883 )   To choose the hospital providing emergency medical service, a relevant evaluation index system was proposed for the capacity of emergency medical service. Two aspects were considered in the choice, i.e., the hospital's capability to provide emergency medical service and the decision-makers' expected quality index of emergency medical service. The closeness degree to expected quality index of optional hospitals was calculated by incentive/penalty function, then all the different evaluated data of emergency medical service capacity were integrated together to obtain the comprehensively evaluated data. The schemes thus obtained were sequenced with a hospital chosen, which represented the hospitals' emergency medical capacity and decision-makers' expectations of the quality index of emergency medical service. An example showed the effectiveness of the method proposed. References | Related Articles | Metrics

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Research on location choice and industry transfer of FDI from cost angle Zhang, Yan-Bo (1); Guo, Ya-Jun (1); Qu, Hong-Min (2) 2010, 31 (2):  293-296.  DOI: - Abstract ( 268 )   HTML   PDF (250KB) ( 747 )   An oligopoly output competition model is developed including both the multinational enterprises and host state enterprises to analyze how the cost factors affect the location choice and FDI withdrawal in the host state. The influence of location choice on FDI involves not only the economic agglomeration but also the cost factors. When the economic agglomeration effect is the same, the cost factors play an important role in location choice. For the region to be chosen, the more advantageous the cost, the stronger the attraction to FDI and the more the FDI enterprises gathering there. When the location cost is too high, FDI that is so sensitive to the variation of cost will withdraw from the FDI gathering area. Today China should provide some appropriate regions in its mid-west part as soon as possible as the new centers to adapt the FDI transfer instead of FDI withdrawal. References | Related Articles | Metrics

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Empirical study on long-term performance of A-share listed companies after their IPOs in Liaoning Province Gao, Ying (1); Li, Xin-Yi (1); Chen, Ting-Ting (1); Jin, Xiu (1) 2010, 31 (2):  297-300.  DOI: - Abstract ( 222 )   HTML   PDF (158KB) ( 797 )   The post-issue operating performance over 3 years after their IPOs of 40 companies in Liaoning Province, which were listed as the A-share firms on stock market from January 1996 to July 2002, is discussed, and the main influencing factors on their business performance are analyzed. Using the Fama-French tri-factor model, the long-term excess profits of those companies over 3 years after their IPOs are calculated to examine their long-term performance. Furthermore, the multi-idividual-sampled Kruskal-Wallis verification, dual-individual-sampled Mann-Whitney U verification and multi-variable regression analysis are used to find out the main influencing factors on the long-term performance. A conclusion is drawn that the long-term performance of the 40 A-share listed companies went to weak on stock market on the whole, and that their performance is in negative correlation with issuing time, volume and price. References | Related Articles | Metrics

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On the opportunity based on chance programming to transfer convertible bond to stock Ma, Da-Ming (1); Yuan, Ying (1); Qu, Bo-Xun (1); Liu, Yang (1) 2010, 31 (2):  301-304.  DOI: - Abstract ( 197 )   HTML   PDF (233KB) ( 841 )   Starting from the option characteristics implied in convertible bonds, the investment value analysis made by an investor was included in the decision-making framework. Based on the multi-stage scenario tree model, the 0-1 integral chance programming was done with the constraint on P/E chance and the investor's decision for transferring bond to stock at a scenario tree node both taken into account. With the empirical analysis using the actual data in the case that the bond had been transferred to stock in HAN-STEEL, the following conclusions were drawn. For the investors the optimum decision is to hold convertible bonds so as to gain the stable return on investment if ensuring that the probability in the whole period of the bond transferring to stock is up to 95%. Compared with the conventional securities option, the upper limit of the value of securities option is restricted by the 0-1 integral chance programming because of the chance constraint on the investment value, thus limiting the investment risk for investors. References | Related Articles | Metrics