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15 May 2007, Volume 28 Issue 5 Previous Issue    Next Issue
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Hybrid intelligent modeling and simulation for ore grinding and classification process Tie, Ming (1); Yue, Heng (2); Chai, Tian-You (2) 2007, 28 (5):  609-612.  DOI: - Abstract ( 315 )   HTML   PDF (1137KB) ( 837 )   Modeling the ore grinding and classification process is very important to the optimization of production index. A hybrid intelligent model is thus developed for the simulation of ore grinding and classification process according to its compositive complexity including nonlinearity, multivariable, time-varying parameters and boundary condition fluctuation. This dynamic model is based on the population balance models for ball mill and sump, TSK (Takagi-Sugeno-Kang) model for net mill power draft, empirical cyclone model together with the RBF networks to compensate for the estimation error of overflow density and particle size distribution. With the actual process data from a grinding circuit of a concentration plant, the simulation results of this hybrid intelligent model have the same dynamic characteristics during the variation in fresh slurry feed velocity, density, particle size distribution and cyclone feed manipulating variables. References | Related Articles | Metrics

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Intelligent control setting with CBR for ore grinding-classification system Zhou, Ping (1); Chai, Tian-You (1) 2007, 28 (5):  613-616.  DOI: - Abstract ( 265 )   HTML   PDF (370KB) ( 664 )   Particle size is a key technical index in ore grinding-classification process, which is so difficult to control effectively with conventional loop control strategies. An intelligent control setting approach based on CBR for the grinding-classification system is proposed by combining intelligent method with conventional loop control. Aiming at the interval control of the particle size index and according to the information on boundary conditions and current operating conditions, a model is set intelligently to update automatically all the basic loop setpoints, thus avoiding the subjectivity and randomicity arising from arbitrary process control setting. Then, the outputs from control loops can track down the updated setpoints relevantly to control the particle size within the target zone. The approach proposed has successfully been applied to the grinding-classification process of a hematite ore processing plant, and its effectiveness is proved evidently. References | Related Articles | Metrics

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T-S fuzzy modeling and control for Nadolschi chaotic systems Zhao, Yan (1); Zhang, Hua-Guang (1) 2007, 28 (5):  617-619+622.  DOI: - Abstract ( 288 )   HTML   PDF (191KB) ( 458 )   The T-S fuzzy models as a new fuzzy modeling method are used to describe accurately the Nadolschi chaotic system whose parameters are given. Then, the parallel distributed compensation (PDC) is applied to the design of a state feedback controller. By using Lyapunov stability theory, the asymptotic stability of the proposed scheme is proved, which turns the interactions between fuzzy sub-systems to full account. The gain matrices of the designed controller can be obtained by solving a set of linear matrix inequalities. Simulation results showed that the designed state feedback controller can control easily the time trajectory of the Nadolschi chaotic system and stabilize it asymptotically so as to get to the zero balance point. The method can also be generalized and extended to the control of other chaotic systems. References | Related Articles | Metrics

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New homotopic path-tracking algorithm based on matlab Hui, Xing-Jie (1); Li, Xia (2); Chen, Yi-Ming (2) 2007, 28 (5):  620-622.  DOI: - Abstract ( 392 )   HTML   PDF (158KB) ( 1287 )   The homotopy continuation algorithm can solve non-linear equations without initial values, but lots of computation shall be done. Therefore, a new homotopic path-tracking algorithm based on Matlab and its function '\' is proposed using secant-prediction and Newton-correction. Examples showed that the algorithm is correct, simple, convenient and reliable, thus offering a way to implement easily the homotopy algorithm. References | Related Articles | Metrics

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Passive analysis and control for discrete-time singular systems Li, Qin (1); Zhang, Qing-Ling (1) 2007, 28 (5):  623-626.  DOI: - Abstract ( 377 )   HTML   PDF (180KB) ( 1076 )   The strict passivity of a class of discrete-time singular systems is analyzed. A sufficient and necessary condition is given by means of strict linear matrix inequality (LMI) for the systems to be admissible and strictly passive. Based on the passive analysis and aiming at the discrete-time systems in which both state and output equations involve the control, the condition that is admissible and strictly passive for the closed-loop system is also analyzed via LMI under the control of state feedback, and the design method of the controller is given. A simulation example is presented to illustrate the effectiveness of the proposed method and show that the condition of strict LMI is simpler and easier to draw the same conclusion in comparison with the condition of non-strict LMI. References | Related Articles | Metrics

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Simulation of dose distribution in radiotherapy treatment Xue, Ding-Yu (1); Liu, Yan-Mei (2); Xu, Xin-He (1); Gao, Wen-Shan (3) 2007, 28 (5):  627-630.  DOI: - Abstract ( 279 )   HTML   PDF (366KB) ( 825 )   A Monte Carlo simulation package combining DPM (dose planning method) with Matlab was developed to solve the dose calculation problems in radiotherapy treatment by rewriting the current radiotherapy software DPM and taking advantage of Matlab for profile visualization, thus obtaining easily the isodose distribution curve and isodose surface contour. The package developed are highly potential in practical applications for its speed-up in simulation and evidently visible results, which showed that this method is correct, effective and capable of enhancing the level of radiotherapy. References | Related Articles | Metrics

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CR condition optimization based on physical feature parameters Zhou, Wei (1); Wang, You-Zheng (1); Zhou, Zhan-Wen (2); Qu, Rui (1) 2007, 28 (5):  631-634+647.  DOI: - Abstract ( 244 )   HTML   PDF (320KB) ( 678 )   The quantitative relation between physical features and computerized radiography (CR) parameters is analyzed with artificial neural network to develop a 0-1 integer planning model based on physical feature parameters, tube voltage, tube current· exposure time and CR scoring according to the satisfiability of relevant photos for body indices. Grouped filtering method was used to simplify the solution space, then the optimized model is solved by genetic algorithm. The result of pleurography (PA) indicates that the conclusion drawn by this CR optimization method, is compatible with experts' long-time clinical experience and that both the artificial neural network and genetic algorithm play the role in CR and solving actual problems. In addition, this method can be used to analyze the CR photos of the rest of body, and extended to other X-ray photographic equipment. References | Related Articles | Metrics

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Case-based decision support system for fault management in water supply system Yuan, Yuan (1); Wang, Ding-Wei (1); Wang, Hong-Feng (1) 2007, 28 (5):  635-638.  DOI: - Abstract ( 212 )   HTML   PDF (864KB) ( 666 )   The framework and work flow of the decision support system are proposed for fault management in water supply system through case-based reasoning as an artificial intelligent method, and the key techniques to implement the system are also discussed. After analyzing in depth the operation process of water supply fault management and extracting the case features from historical fault records, two sets of variable weights are given to the case features in case retrieval so as to implement the two core system functions: fault monitoring and fault handling. With the optimized valve shutoff scheme, simulation model of water distribution network under fault condition and two-level optimal scheduling model introduced in, the function of fault handling can be ensured even though no historical cases can be referred to, and the case database is thus substantiated further. The feasibility and validity of the system proposed are illustrated by its operating results. References | Related Articles | Metrics

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Dynamic problem optimization using the improved primal-dual genetic algorithm Wang, Hong-Feng (1); Wang, Ding-Wei (1); Liu, Li-Li (1) 2007, 28 (5):  639-642.  DOI: - Abstract ( 235 )   HTML   PDF (250KB) ( 937 )   The PDM (primal-dual mapping) as a key operation in PDGA (primal-dual genetic algorithm) that has successfully been applied to the dynamic 0-1 optimization problems is improved, and a new adaptive PDM scheme is proposed. Then, the statistical information on the allele distribution in each locus over the population is used to calculate the probability of PDM in the corresponding locus. Simulation results from a set of dynamic benchmark problems showed that the improved PDGA outperforms the original algorithm in dynamic environment. References | Related Articles | Metrics

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Efficient access control in hyprid peer-to-peer environments Zhang, Qian (1); Zhang, Xia (1); Liu, Ji-Ren (1) 2007, 28 (5):  643-647.  DOI: - Abstract ( 243 )   HTML   PDF (1335KB) ( 511 )   One of key requirements for the control mechanism in P2P systems is access control which becomes more critical when peers enter into or leave a collaboration community. However, the convential access control mechanism is not suitable because the P2P system is a decentralized and dynamic one. An approach is thus proposed for providing an efficient access control mechanism in hybrid P2P environments, i.e., it supports the role-based access control mechanism in a collaboration community comprising both leaf peers and super peers in hybrid P2P networks. Furthermore, to support access control among different communities, a trust-based access control mechanism is proposed so as to form a trustful cooperating environment. Compared to other existing approaches, the proposed one is content-based and fine-grained with the trust differences between peers taken into account, so highly applicable to hybrid P2P computing environments. References | Related Articles | Metrics

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Semi-blind multi-user detection based on improved PASTd subspace tracking algorithm Meng, Yan (1); Wang, Jin-Kuan (1); Song, Xin (1); Han, Ying-Hua (1) 2007, 28 (5):  648-651.  DOI: - Abstract ( 274 )   HTML   PDF (1134KB) ( 498 )   Several algorithms of subspace tracking are investigated. The eigenvalue decomposition (EVD) and singular value decomposition (SVD) are not suited for engineering implementation because of their high computation complexities, while the PASTd algorithm brings about very slow convergence rate because of the non-orthogonality of estimated eigenvectors though its computation complexity is low. An improved PASTd subspace tracking algorithm is therefore proposed to be applied to the subspace-based semi-blind multi-user detector for adaptive subspace estimation. The algorithm proposed can insure the orthogonality of the eigenvectors, thus quickening its convergence rate. Simulation results show that the proposed algorithm is superior to both the PASTd semi-blind multi-user detection and OPAST semi-blind multi-user detection in convergence rate, bit error rate (BER) and output signal interference to noise ratio (SINR), and approaches to the SVD semi-blind multi-user detection with relatively low computing speed kept. References | Related Articles | Metrics

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Preemptive scheduling strategy for wireless sensor networks operating system Yin, Zhen-Yu (1); Zhao, Hai (1); Xu, Jiu-Qiang (1); Wang, Xiao-Ying (2) 2007, 28 (5):  652-655.  DOI: - Abstract ( 253 )   HTML   PDF (285KB) ( 564 )   A preemptive scheduling strategy, IS-EDF (idle sleep-earliest deadline first) is proposed for the operation system of wireless sensor networks and implemented on TinyOS. Thus the priority of the tasks on wireless sensor nodes can be adjusted dynamically so as to ensure the high priority of important task to be executed and improve the system response characteristic of the nodes under heavy task load. When a wireless sensor node is idle, the IS-EDF can bring the node into sleep mode for energy saving. Experiment and simulation results showed that the IS-EDF scheduling strategy can effectively improve the system response characteristic of the wireless sensor nodes under heavy load at the cost of small increase in energy consumption. References | Related Articles | Metrics

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Efficient trust model for peer-to-peer environment Liu, Zheng (1); Zhang, Qian (1); Wen, Xue-Zhi (1) 2007, 28 (5):  656-659.  DOI: - Abstract ( 276 )   HTML   PDF (232KB) ( 555 )   The current single trust model can not deal with the trust computation well for different aspects and, on the other hand, the multiple-grain trust model only considers the inclusion relation between different domains but takes no account of their intersection relation. A novel Peer-to-Peer trust model is thus presented on the basis of domain model, which considers both the trust computation of different aspects and the intersection relation between different domains. Defining the domain model, the trust model is formally defined. Then, the convergence of iteration for trust computation is analyzed and the methods of distributed placement and acquisition of trust are given. Compared to the current trust model, the proposed one is more precision in trust computation of multiple aspects and more feasible in practical projects to compute peer trust. References | Related Articles | Metrics

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Mechanism of minimizing SIP messages in wireless network Geng, Fu-Quan (1); Feng, Zhen (1); Zhao, Lin-Liang (1); Wang, Guang-Xing (1) 2007, 28 (5):  660-663.  DOI: - Abstract ( 285 )   HTML   PDF (369KB) ( 591 )   3GPP has decided that SIP should be chosen as a control protocol of its core network. But SIP messages are usually too lengthy even become a bottleneck of its application in wireless network. SigComp technology is thus presented as a usual solution to the problem, and a new scheme called smart profile is proposed. Both test results and theoretical analysis indicate that the new scheme will not only minimize the size of SIP messages to be transmitted and save the channel resources, but also reduce the delay of transmitting SIP signal in wireless network. References | Related Articles | Metrics

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Modeling the effect of laminar cooling pattern on microstructure and mechanical properties of plates in rolling process Tan, Wen (1); Wu, Di (1); Xue, Wen-Ying (1); Liu, Zhen-Yu (1) 2007, 28 (5):  664-667.  DOI: - Abstract ( 246 )   HTML   PDF (291KB) ( 430 )   To investigate the effect of different laminar cooling patterns on the microstructure and mechanical properties of plates in rolling process, the changes in temperature and microstructure of plate in such cooling process were calculated simulatively by coupling finite difference method with microstructural evolution models, thus predicting the ferrite grain size and phase composition under different cooling patterns. In addition, the yield/tensile strength were also predicted through the structure-property models and verified by tests. Simulation and rolling test results showed that the effect of laminar cooling patterns on the plate products is small in final phase composition but great in ferrite grain size. A two-stage cooling pattern was proved all the better for both plate's structure and mechanical properties. References | Related Articles | Metrics

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Effect of crystallization process on microstructure of glass-ceramics from ferrous tailing Shi, Pei-Yang (1); Wang, Yuan-Yuan (1); Zhang, Da-Yong (1); Jiang, Mao-Fa (1) 2007, 28 (5):  668-671.  DOI: - Abstract ( 286 )   HTML   PDF (612KB) ( 1611 )   Glass-ceramics were prepared from ferrous tailing as the main raw material. The effect of crystallizing temperature/time on the microstructure of glass-ceramics was investigated comprehensively by DTA, XRD and SEM. It was found that the major crystalline phase is hedenbergite existing in the sample. Which remains unchanged with increasing crystallizing temperature though the crystalline morphology and crystallization rate change greatly. Furthermore, the crystals become more regular and crystal size becomes bigger with increasing crystallizing temperature, and the crystallization rate increases first and then decreases. When the temperature is higher than 1250°C, the crystal distribution becomes less uniform, and the optimum crystallizing temperature and time are 1200-1270°C and 180 min, respectively. References | Related Articles | Metrics

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Thermodynamic calculation model of nitrogen solubility in molten stainless steel Li, Hua-Bing (1); Jiang, Zhou-Hua (1) 2007, 28 (5):  672-675.  DOI: - Abstract ( 388 )   HTML   PDF (520KB) ( 1220 )   A new thermodynamic model was developed to calculate the nitrogen solubility in molten stainless steel, in a wide range of system temperature, nitrogen partial pressure and alloying constituents by introducing an interaction coefficient expressing the effect of nitrogen partial pressure on nitrogen activity coefficient on the basis of experiments and other authors' earlier works. The calculation results were in good agreement with measured values, with which the influences of nitrogen partial pressure, temperature and alloy constituents on the nitrogen solubility in molten stainless steels were discussed. Under high pressure especially the high concentration of alloying elements, it was found that the relationship between nitrogen solubility in liquid stainless steels and nitrogen partial pressure doesn't follow Sievert's law. The dependence of temperature on the nitrogen solubility is determined by the composition of alloying elements under a certain nitrogen partial pressure. The mass fraction of nitrogen in the 20%Cr-20%Mn alloy can be up to 0.8% at 1873 K under normal pressure (N2 partial pressure = 0.1 MPa). References | Related Articles | Metrics

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Numerical simulation of flow field of flying vehicle Yu, Liang (1); Ru, Hong-Qiang (1); Zhong, Lei (1); Zuo, Liang (1) 2007, 28 (5):  676-679.  DOI: - Abstract ( 309 )   HTML   PDF (1278KB) ( 601 )   Taking the Soyuz reentry module and F16 fighter as examples, the three-dimensional flow field, surface temperature and heat flux distribution of a single high-speed flying vehicle of either the simple or complex configuration were simulated numerically by COSMOS FloWorks on PC. The flow pattern of the reentry module was calculated, and it was found that there is a similarity between the reentry module and 'wave rider' F16 fighter with regard to the distributions of surface heat flux, temperature and pressure, i.e., the position where the heat flux is high corresponds to that where both the surface temperature and pressure are also high. The result can provide theoretically a reference for an integral optimization of aircraft and its design for thermal protection. References | Related Articles | Metrics

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Effects of sodium silicate nanahydrate and PAM on dispersion of Nano SiO2 Wang, Yi (1); Niu, Yong-Xiao (2); Wang, En-De (2); Fu, Jian-Fei (2) 2007, 28 (5):  680-682+695.  DOI: - Abstract ( 321 )   HTML   PDF (990KB) ( 490 )   Sodium silicate nanahydrate and PAM were selected as dispersants to evaluate the dispersive stability of nanoparticles through a diffraction-based laser granulometric analyzer. An IR spectrometer was used to identify the adsorption state of dispersant in the surface of nanoparticles. The results indicated that the combination of sodium silicate nanahydrate with PAM can play the role of synergistic reaction to improve effectively the dispersive stability of SiO2 nanoparticles in aqueous solution. It was found that adding the sodium silicate nanahydrate before PAM is better than adding them in reverse order for dispersive stability, if the amounts of both additions are the same. References | Related Articles | Metrics

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Theoretical study on structures and stabilities of endofullerenes M@C50 Wang, Dong-Lai (1); Gu, Hui-Min (1); Shen, Hong-Tao (1); Zhai, Yu-Chun (1) 2007, 28 (5):  683-686.  DOI: - Abstract ( 238 )   HTML   PDF (782KB) ( 482 )   Based on the B3LYP density functional theory, the LANL2DZ basis set was employed to study the equilibrium geometries and vibration frequencies of two kinds of the isomers C50 with D5h/D3, symmetry and the clathrate M@C50 [M = Be, Mg, Ca, Sr, Ba] as the 2nd main group formed with the isomers as radicals. The energy level difference of frontier molecular orbital, net atomic charge and binding energy were calculated. The results indicated that the endofullerenes D5h M@C50 are more stable than the D3M@C50. For the same symmetry D5h, the stabilities of different endofullerenes are in order of their atomic number from low to high. Thermodynamic factors are thus quite favorable for the formation of Sr@C50 and Ba@C50. References | Related Articles | Metrics

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Optical properties of Al2O3 thin film prepared through medium-frequency reactive magnetron sputtering process Liao, Guo-Jin (1); Wen, Li-Shi (2); Ba, De-Chun (1); Liu, Si-Ming (3) 2007, 28 (5):  687-691.  DOI: - Abstract ( 260 )   HTML   PDF (328KB) ( 1237 )   Aluminum oxide thin films were deposited through the medium-frequency reactive magnetron sputtering process. An effective and simple way was therefore developed to analyze the optical properties of low-absorbability films and other relevant physical properties by use of transmittance spectroscopy for Al2O3 film samples. The dependences of refractive index and extinction coefficient on wavelength were calculated in this way. The interrelation between incident light wavelength, refractivity, absorptance and film thickness of Al2O3 films is discussed, thus giving the relationship between the refractivity, absorptance and incident light wavelength in the range of 400-1000 nm, as well as the formula of Al2O3 film thickness. References | Related Articles | Metrics

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Digestion technology with Weipa ore as sweetening ore Wang, Yi-Yong (1); Zhang, Ting-An (1); Ke, Xian-Yao (1); Jiang, Xiao-Li (1) 2007, 28 (5):  692-695.  DOI: - Abstract ( 297 )   HTML   PDF (390KB) ( 476 )   The digestion efficiency of Australian Weipa ore and using it in digestion process were investigated. Effects of sweetening temperature/time and dosage of Weipa ore on the digestion efficiency were comparatively studied. The results showed that Weipa ore is gibbsite and its leaching efficiency is high when digested at higher than 200°C, so applicable to sweetening ore in digestion process, under conditions that the sweetening process is controlled in the range of 195-200°C for 15-20 min and the dosage of Weipa ore is 15wt%-20wt% of the quantity of ore added in the process of Bayer process. The slurry thus sweetened shows an excellent settling compression performance. References | Related Articles | Metrics

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Properties of alumina-particles-reinforced silver composite Li, Feng-Hua (1); Chen, Shan-Shan (1); Fan, Zhan-Guo (1) 2007, 28 (5):  696-700.  DOI: - Abstract ( 227 )   HTML   PDF (1168KB) ( 657 )   To overcome the high-temperature defects of Ag used as the substrate of superconducting tape and improve the mechanical properties and melting point of Ag, the alumina whose melting point is high was selected as a doping to prepare Al2O3/Ag composite through conventional powder metallurgy. The results indicated that over 1wt% Al2O3 particles doped in Ag matrix can raise the melting point tm of Ag up to 970°C and 3wt% Al2O3 particles can raise that up to 990°C. It was found that among the samples doped with Al2O3 particles less than 3wt%, the 2% Al2O3/Ag composite has the maximum hardness and tensile strength and minimum linear coefficient of expansion and elongation percentage. Since the sample 2% Al2O3/Ag composite has proper melting point, suitable linear coefficient of expansion in proximity to that of the YBaCuO superconductor and best mechanical properties, it meets the posterior heat-treatment requirements for YBaCuO superconducting tapes in Ar atmosphere. References | Related Articles | Metrics

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Performance analysis and experimental study on a wind-driven fan installed on roof Wang, Cheng-Yang (1); Xu, Guang-Jun (1); Gao, Biao (1); He, Ji-Cheng (1) 2007, 28 (5):  701-703.  DOI: - Abstract ( 244 )   HTML   PDF (358KB) ( 751 )   Performance and energy conversion mechanism of a wind-driven fan installed on roof were studied through kinematical analysis and experiment. Most of the meniscus fan blades can generate a driving torque under the action of natural wind to rotate the fan and prevent the downward shearing wind from counter pressure difference which is unfavorable to natural draft, no matter what the incident angle of natural wind is. On the other hand, the fan's draft inducibility is enhanced somewhat with increasing wind speed. It implies that the fan itself has a draft inducibility to a certain extent in addition to that due to power density difference, and the investigation on how to utilize the low power density wind energy will be a new way to develop renewable energy resources. References | Related Articles | Metrics

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Reliability model of failure-dependent system with frequency of loading taken into account Wang, Zheng (1); Xie, Li-Yang (1); Li, Bing (1) 2007, 28 (5):  704-707.  DOI: - Abstract ( 240 )   HTML   PDF (321KB) ( 795 )   The effect of frequency of random loading on the reliability of system is studied, and the reliability models of failure-dependent system under the action of random load are developed by use of the load-strength interference model and theory of order statistics. Considering the failure-dependence on components in the system, the reliability models of series and parallel systems are developed separately by the system-level load-strength interference model without the precondition of failure independence assumed. According to the statistical meaning of random loading, the cumulative distribution function and the probability density function of equivalent load are derived through the order statistic theory when the random load acts many times. Thus, the reliability models of failure-dependent systems are developed when the random load is acting on them many times. The Monte Carlo method is then applied to the simulation experiment for the reliability model of failure-dependent series system on which the random load acts many times and the result shows that the model proposed is effective. References | Related Articles | Metrics

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Application of MCEWMA control chart in tool wear monitoring process Cui, Jing-Wei (1); Xie, Li-Yang (1); Liu, Xiao-Xia (1) 2007, 28 (5):  708-711.  DOI: - Abstract ( 253 )   HTML   PDF (268KB) ( 758 )   To utilize a control chart effectively, the exponentially weighted moving average (EWMA) method is introduced in to forecast the linear variation of shaft diameter resulting from tool wear. Based on EWMA, the MCEWMA control chart is proposed to monitor tool wear process, i.e., the moving center-line EWMA. In the whole service life of a tool used in machining process, the tool wear and relevant random fluctuation are both regarded as the common causes in tool wear monitoring process, thus avoiding the frequent false alarm when using conventional control chart. An example is given to illustrate the criterion for selecting chart parameters. References | Related Articles | Metrics

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Application of XML in networked manufacturing based on STEP-NC Sun, Jun (1); Li, Li (2); Wang, Jun (2); Wang, Wan-Shan (1) 2007, 28 (5):  712-716.  DOI: - Abstract ( 235 )   HTML   PDF (342KB) ( 739 )   EXPRESS language should be transformed into XML language when applying STEP-NC, a new NC programming language, to the cooperative manufacturing within a network for the integration and share of the product information among manufacturers, thus enabling them to share and exchange the information under remote and heterogeneous conditions. The data types and features of EXPRESS and XML languages and the mapping method between them are discussed, then two transformation techniques between them are put forward on the basis of XML schema library and DOM interface. The way of how to use DOM interfaces to implement the transformation definitely is therefore given to support technically different manufacturers to develop their cooperative product designs for networked manufacturing. References | Related Articles | Metrics

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Spatio-temporal variability of groundwater level in China's Hebei plain Liu, Zhi-Guo (1); Wang, En-De (1); Fu, Jian-Fei (1); Shao, An-Lin (1) 2007, 28 (5):  717-720.  DOI: - Abstract ( 284 )   HTML   PDF (783KB) ( 652 )   Based on the spatially analytic function of GIS, the spatio-temporal variability of groundwater level in China's Hebei plain was studied by using the semivariogram and ordinary Kriging method of geostatistics, from which the spherical model fitted both the data sets in the periods 1986-1990 and 1996-2000. The spatial heterogeneity of groundwater level caused by its authigenic factors was big and, as an anisotropic result of groundwater level, it was found that there was a significant level difference in the period 1986-1990. The spatial distribution mapping of groundwater level by Kriging interpolation with the data of groundwater level in 1986-1990 and 1996-2000 showed that the trend of spatial distribution as a whole is that the groundwater level becomes high gradually from east to west and from the littoral plain to the piedmont plain, and the groundwater in the west middle plain is deeper than in the littoral plain. In conclusion, on the whole, there was a drawdown in the period from 1986 to 2000 because of such influencing factors as population, irrigation area, rainfall and run-off, which affects seriously the sustainable economic development of Hebei Province. References | Related Articles | Metrics

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Screening and domestication of microorganism used in oil contaminated wastewater remediation Xu, Xin-Yang (1); Gu, Ni-Na (1) 2007, 28 (5):  721-724+740.  DOI: - Abstract ( 231 )   HTML   PDF (515KB) ( 823 )   According to the characteristics of oil contaminated wastewater, four strains of microorganism, named TA-11, TA-17, HA-9 and HD-1, which can degrade oil and CODCr in oil contaminated wastewater, were picked out through screening/domestication from the oil contaminated soil and activated sludge in the wastewater treatment system of a pitch plant in Panjin, China. Experimental results showed that any of the four strains of microorganism can remove oil and CODCr from the oil contaminated wastewater effectively with a highest removal rate of CODCr up to 68% at 30°C and pH value 7.0 if treated for 64 h. And it was revealed that the removal rate of CODCr from oil contaminated wastewater is much higher by mixed bacilli than by single bacillus. References | Related Articles | Metrics

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Sepiolite adsorption for aqueous ascorbic acid Su, Xiu-Juan (1); Zhu, Yi-Min (1); Zhao, Er-Hua (1); Wei, De-Zhou (1) 2007, 28 (5):  725-728.  DOI: - Abstract ( 239 )   HTML   PDF (320KB) ( 665 )   The sepiolite was taken from Xiangtan, Hunan Province as an adsorbent. The ascorbic acid was adsorbed by the sepiolite in wastewater and the process was investigated experimentally. The results indicated that after 6.0 min the sepiolite has an adsorption efficiency up to 55% if the dose is 15 g/L with a pH value 5.5 and the initial concentration of ascorbic acid is 150 mg/L, while the efficiency becomes 66.3% if the initial concentration of ascorbic acid is 70.0 mg/L. The saturated adsorption is 6.5 mg/g. Adding a bit of polymerized aluminum chloride into the wastewater can improve greatly the adsorption efficiency, which is possibly due to the synergistic reaction of adsorption with flocculation. According to the test results, the particle size of the sepiolite is fine with high specific surface area. So the sepiolite is naturally a harmless adsorbent available to be used for quite thorough wastewater. References | Related Articles | Metrics

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Inhibition influence of extraction liquids from Stellera chamaejasme root on seed germination Cao, Cheng-You (1); Fu, Yao (1); Wang, Wen-Xing (1); Gao, Fei-Fei (1) 2007, 28 (5):  729-732.  DOI: - Abstract ( 513 )   HTML   PDF (331KB) ( 1266 )   Substances in Stellera chamaejasme root were extracted by water and ethanol separately, and the influences of the two extraction liquids of different concentrations, i.e., diluted to 0, 10, 20 and 50 times as thin as original extraction liquids, on seed germination and physiological indexes of 2 plants were studied. The results showed that both the original extraction liquids and their 10-20 times dilutions significantly inhibit the seed germination percentage and germinating process. The inhibitability of ethanol-extracted liquid is higher than that of water-extracted one, and the lower the concentration, the weaker the inhibitability. Physiological responses of the 2 plants were induced under extraction liquid treatments. It was found the soluble sugar and protein contents in seeds decrease, while proline content in seeds and malondialdehyde (MDA) content in seedlings increase with weakened superoxide dismutase (SOD) activity. References | Related Articles | Metrics

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Creep effect analysis of steel reinforced concrete beam Mu, Guang-Bo (1); Wang, Lian-Guang (1); Wang, Che (2) 2007, 28 (5):  733-736.  DOI: - Abstract ( 190 )   HTML   PDF (394KB) ( 536 )   To study the creep effect on steel reinforced concrete beam, a mathematic model of creep function was developed, then some analytic models based on visco-elasticity theory were given to the computation procedure of creep effect, such as the bearing capacity, strain variation, deformation and interface slip. Results of the computation along the whole span of SRC beam showed that the values of mid-span moment, strain and deformation are maximum, while the mid-span slip value is minimum. During the initial stage of loading, the values of all these parameters change obviously, and later on they approach to constant. References | Related Articles | Metrics

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Stress analysis of prestressed steel-concrete composite beams reinforced with FRP strips Liu, Li (1); Wang, Lian-Guang (1); Zhao, Jun (2); Lu, Zhen (2) 2007, 28 (5):  737-740.  DOI: - Abstract ( 274 )   HTML   PDF (1035KB) ( 484 )   Taking advantage of FRP (fiber-reinforced polymer) that is anticorrosive, light and of high strength, the FRP strips were stuck on the flange bottom of H-beam of a simply-supported prestressed steel-concrete composite beam, thus enabling the composite beam to reduce effectively its deformation and improve its load-bearing capacity. Based on numerical integration and taking account of the beam' s nonlinear materials, the nonlinear analytic models are developed for the beam in the whole process from receiving load to failure. Then, the computation procedure is programmed to obtain the relationship between load and deformation and that between load and prestressed increment. The whole process is thus analyzed nonlinearly to clarify the working characteristics of the composite beam in different stress/strain variation phases. An example is given to verify the validity of the analytic models proposed. References | Related Articles | Metrics

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Application of CCM to deformation of FRP-restrained concrete column Zhou, Le (1); Li, Ning (2); Wang, Lian-Guang (1) 2007, 28 (5):  741-744.  DOI: - Abstract ( 187 )   HTML   PDF (286KB) ( 503 )   The deformation behavior of FRP (fiber reinforce plastic)-restrained concrete column are discussed, as well as the influencing parameters on it. Taking advantage of the feature of catastrophe theory, the relation between axial load ratio and total creep deformation is analyzed for the FRP-restrained concrete column under the action of long-term load. A CCM (cusp catastrophe model) on creep deformation (S), axial load ratio (N) and column performance (R) is then developed, where the existing test data are used to determine the parameters α, β, γ and the axial load ratio k as a coefficient. The calculated results of F value are so close to its theoretical results, it means that there is a goodness of fit between the theoretical and actual results of S-R-N relation by the cusp catastrophe model, thus verifying the high accuracy of the model. References | Related Articles | Metrics

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Testing for ground back pressure acting on bottom of a new-type foundation and its stress distribution Li, Chun (1); Zhu, Fu-Sheng (1); Pan, Xiu-Yan (2) 2007, 28 (5):  745-748.  DOI: - Abstract ( 238 )   HTML   PDF (392KB) ( 553 )   The GYH-2 membrane case manometer and GJL-2 reinforcement stressometer were used to test the ground back pressure acting on the bottom of a new-type spread foundation integrated with concrete slab and its stress distribution. First-hand dynamic data were thus monitored and recorded to generalize the actual distributions of the back pressure and foundation's stress. Testing results showed that the concrete slab can take on about 30% load of upper structure; stress of reinforcements change alternately; the maximum tensile stress occurs at the midspan of slab and the maximum value of stress is about 22% lower than allowable strength of reinforcements. This conclusion offers directly a reference for designing the spread foundation integrated with concrete slab. References | Related Articles | Metrics

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Industrial structure, R&D spillover and cooperation between up/downstream companies for innovation strategies Wang, Qiu-Fei (1); Li, Kai (1); Xu, Bo (1) 2007, 28 (5):  749-752.  DOI: - Abstract ( 238 )   HTML   PDF (301KB) ( 741 )   Utilizing the Cournot's quantity competition model, how the industrial structure and R&D spillover affect the cooperation between upstream and downstream companies for their innovation strategies were comparatively analysed. The results indicated that the upstream market monopolistic structure is beneficial to the downstream companies to innovate their R&D activities, while the competitive upstream one is beneficial to the upstream companies to do such activities. When the industrial structure is monopolistic, in the upstream companies the profits and social welfare for employees decrease with their increasing R&D spillover and, when the industrial structure is competitive in the upstream ones they increase first then decrease but the downstream ones remain their profits unchanged. References | Related Articles | Metrics

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Emergency replenishment model and analysis of distribution systems in collaborative commerce Ji, Shou-Feng (1); Du, Xiao-Lu (1); Huang, Xiao-Yuan (1) 2007, 28 (5):  753-756.  DOI: - Abstract ( 235 )   HTML   PDF (1029KB) ( 657 )   Demand information sharing plays an important role to reduce total inventory cost in the system of one warehouse with multiple retailers. Under the preconditions that the periodic check-up is taken as inventory strategy at all nodes in the system, replenishment is to be done at fixed intervals, lead time is comparatively shorter than replenishment interval and emergency replenishment from upstream supplier(s) is available when stock-out happens, the ETC (expected total cost) models are developed in either case, i.e., information' shareable in collaborative commerce or unavailable to get. A numerical example is given to illustrate that the demand information sharing can attain the goal to reduce the cost of the system and that keeping the highest inventory level dynamical is indispensable to the benefit which the central warehouse is attempting through demand information sharing. References | Related Articles | Metrics

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Existence and multiplicity of positive periodic solutions to functional differential equations with infinite delay Sun, Tao (1); Liu, Chao (1); Duan, Xiao-Dong (2) 2007, 28 (5):  757-760.  DOI: - Abstract ( 242 )   HTML   PDF (160KB) ( 593 )   A class of positive periodic functional differential equations are investigated by nonlinear functional analysis including the fixed point index theorem, operator theorem and cone theory. Compared with the earlier works as shown in reference, both the existence and multiplicity theorems of such functional differential equations with infinite delay are obtained. An example is given to illustrate the conclusion drawn, where the effectiveness of the existence and multiplicity theorems is further proved by Hematcpoiesis model for the positive periodic solutions to the functional differential equations with infinite delay. References | Related Articles | Metrics