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15 October 2006, Volume 27 Issue 10 Previous Issue    Next Issue
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Quadratic stability of T-S discrete fuzzy systems Yang, Xiao-Guang (1); Zhang, Qing-Ling (1); Liu, Xiao-Dong (2); Liu, Pei-Yong (1) 2006, 27 (10):  1063-1066.  DOI: - Abstract ( 219 )   HTML   PDF (165KB) ( 542 )   Studies the quadratic stability of T-S discrete fuzzy systems for the purpose to obtain the simpler conditions for stability than that as shown in earlier works. The sufficient conditions for quadratic stability are given by introducing the Lyapunov function adaptable to T-S discrete fuzzy systems. Then, the nonlinear matrix inequalities were converted into linear matrix inequalities (LMIs) by using the Schur complement, thus converting the T-S discrete fuzzy systems into convex combination ones with simpler LMI-based sufficient conditions given to quadratic stability. A numerical simulation was done to exemplify that such problems can be solved by using LMI and MATLAB and verify that the result of the theorem derived in this paper is better than those in earlier works. In this way the problems of robust control and H∞ control could be studied further. References | Related Articles | Metrics

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Simulation of fuzzy adaptive PID control in coke oven process control Gao, Xian-Wen (1); Zhao, Ya-Ping (1) 2006, 27 (10):  1067-1070.  DOI: - Abstract ( 266 )   HTML   PDF (194KB) ( 850 )   Combining both the advantages of PID controller and fuzzy control, a fuzzy adaptive PID controller is proposed for the characteristics of coke oven, such as big inertia, pure time-delay, nonlinearity and time-varying. The algorithm of fuzzy adaptive PID control is analyzed theoretically and the simplified production model of coke oven is simulated. The results showed that such a fuzzy adaptive PID controller has the advantages of shortening the time for system readjustment, quickening the response speed, higher anti-interference ability and adaptability to parameters' changing than conventional PID controller and better dynamic property/stability. All these can reduce effectively the fluctuation of coke oven temperature. References | Related Articles | Metrics

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Soft sensor modeling based on hierarchical T-S fuzzy system Yuan, Ping (1); Mao, Zhi-Zhong (1); Wang, Fu-Li (1) 2006, 27 (10):  1071-1074.  DOI: - Abstract ( 218 )   HTML   PDF (1184KB) ( 598 )   When introducing the hierarchical fuzzy system in soft sensor modeling, the rational structure of the fuzzy system is very important to the performance of the soft sensor model. To select the rational system structure, an HTFS (hierarchical T-S fuzzy system) based soft sensor model is developed by virtue of MOGA (multi-objective genetic algorithm) and dichotomy. JV10GA selects the input variables of subsystem in accordance to the importance of each input variable in a sub fuzzy system, while dichotomy is used to divide the input space unevenly on the basis of the characteristics of T-S fuzzy system. The proposed method can simplify the structure of model and improve the generality, with the accuracy of the soft sensor model perfectly improved. The simulation results demonstrate the practicability and efficiency of the HTFS based soft sensor model. References | Related Articles | Metrics

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Rule design of fuzzy control of sintering machine and its simulation Guo, Li-Xin (1); Li, Hao (1); Huang, Qiu-Ye (1); Chen, Wei (1) 2006, 27 (10):  1075-1078.  DOI: - Abstract ( 228 )   HTML   PDF (785KB) ( 612 )   Actually the control of burning-through point is quite a complex process, which is often subjected to the influences exerted by many factors. To discriminate correctly the burning-through point in sintering process, a fuzzy control system of sintering process is modeled and a new value assignment method is proposed for the burning-through point to enable a more reasonable design for the discrimination of burning-through point in sintering process with a real-time control ensured. The results show the control system can provide a fast response, which is advantageous to improving the quality of sintered ore and decreasing the fault rate of sintering machine. References | Related Articles | Metrics

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On-line estimation of specific growth rate in fermentation process Sang, Hai-Feng (1); He, Da-Kuo (1); Zhang, Da-Peng (1) 2006, 27 (10):  1079-1082.  DOI: - Abstract ( 257 )   HTML   PDF (191KB) ( 972 )   The specific growth rate is one of the key parameters in fermentation process, but to get its value on-line is difficult because of lack of reliable sensors. An on-line estimation of the specific growth rate in aerobic fermentation process is thus proposed by measuring CER (carbon dioxide excretion rate) and then selecting the important parameters in the model through optimization. It is very easy to implement since the carbon dioxide excretion rate can be obtained easily. This method has been applied to Nosiheptide fermentation process in which the specific growth rate is given by an estimator computing the biomass. The results show that the estimated values conform well with the measured values, i.e., the proposed method is reliable and practical. References | Related Articles | Metrics

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Forecasting system marginal price of electricity by dynamic neural network Lin, Zhi-Ling (1); Gao, Li-Qun (1); Zhang, Da-Peng (1); Zhang, Qiang (1) 2006, 27 (10):  1083-1086.  DOI: - Abstract ( 253 )   HTML   PDF (739KB) ( 606 )   Analyzing the characteristics of SMP (system marginal price), the electrical load and the historically corresponding and current SMP trends are regarded as the three main influencing factors on forecasting the oncoming SMP value. A recurrent neural network is therefore introduced into forecasting SMP, because it is available to mapping dynamic system and SMP is regarded as a result of dynamic running on power market. To rise above the difficulty of determining NN's structure and weights, the GA optimization algorithm is used to get them by combining binary encoding with real encoding. The historically corresponding market data verified that this method is effective and the forecasting model is accurate. References | Related Articles | Metrics

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Reactive fault-tolerant integrated QoS unicast routing scheme for NGI Wang, Xing-Wei (1); Cai, Shu-Xiang (1); Huang, Min (1) 2006, 27 (10):  1087-1090.  DOI: - Abstract ( 169 )   HTML   PDF (849KB) ( 472 )   IP over DWDM optical Internet is one of the main networking techniques for NGI (next generation Internet), and how to improve its fault-tolerant capability and QoS (quality of service) becomes critical, to which the fault-tolerant QoS routing is one of the effective solutions. A reactive fault-tolerant integrated QoS unicast routing scheme is thus proposed on the basis of heuristic A algorithm to seek for proper routing with wavelength assignment simultaneously. Its objective is trying to offer the best balance among delay, load and the cost of wavelength conversion in addition to improving the effective wavelength utilization and failure restoring rate. Simulation results showed that the proposed scheme is feasible and effective. References | Related Articles | Metrics

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Adaptive thread pool technique based on object pool pattern Xia, Li (1); Zhao, Jing-Bo (2); Jing, Wei-Dong (1); Wang, Guang-Xing (1) 2006, 27 (10):  1091-1094.  DOI: - Abstract ( 239 )   HTML   PDF (164KB) ( 780 )   To determine the number of threads in thread pool, an adaptive thread pool technique based on object pool design-pattern is proposed utilizing the prediction algorithm based grey system theory to predict the number of threads in thread pool in keeping with that required. Then, a scheme is presented to improve efficiency of server and ensure the QoS for client. The scheme utilizing adaptive thread pool technique has been applied to develop the telephone fee payment system and its performance is improved as expected. References | Related Articles | Metrics

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Unvoiced-speech-signal recognition based on optimizing SEMG signal features Wang, Xu (1); Jia, Xue-Qin (1); Li, Jing-Hong (1); Yang, Dan (1) 2006, 27 (10):  1095-1097.  DOI: - Abstract ( 243 )   HTML   PDF (755KB) ( 652 )   Based on genetic algorithms (GA) and Fisher projection, a method is proposed to solve the optimal discriminant basis. New optimal eigenvector separability is obtained by projecting the original eigenvector to the optimal discriminant basis. The surface electromyogram (SEMG) signal of six unvoiced Chinese vowels are detected from the skin surface of zygomaticus major and anterior belly of the digastric, with AR model coefficients, cepstral coefficients and MFCC coefficients of SEMG signal taken as the original eigenvector. And the suboptimal eigenvector is found out from the original one by GA. Projecting the suboptimal eigenvector selected by GA to optimal discriminant basis, the optimal discriminant eigenvector is given. Experiments show that the improved BP neural network has preferable classification performance with optimal discriminant features. References | Related Articles | Metrics

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Low temperature toughness of weld joint of ANS500 super steel strip Gao, Cai-Ru (1); Liu, Xiang-Hna (1); Du, Lin-Xiu (1); Wang, Guo-Dong (1) 2006, 27 (10):  1098-1101.  DOI: - Abstract ( 471 )   HTML   PDF (338KB) ( 754 )   The 6 mm-thick ANS500 super steel strip was welded by gas metal arc welding. A series of Charpy impact tests were done to investigate low-temperature toughness of its weld joints, and the values of toughness were measured at different temperatures to make sure of some temperature ranges that normally correspond to different toughness values. The ductility-brittle transition temperature (DBTT) of different positions of a weld joint was determined by means of impact energy and fracture morphology. When using φ1.0 mm welding wires at 160 A/22 V, The DBTT of weld metal, weld bond and HAZ were measured to be -65°C, -70°C and &le-70°C, respectively, with an safe operating temperature above -65°C. When using φ0.8 mm welding wires at 110 A/21 V, the DBTT of weld metal, weld bond, HAZ were all below -70°C, with a safe operating temperature above -70°C. References | Related Articles | Metrics

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Slab discharging time control for plate rolling line Jiao, Zhi-Jie (1); Hu, Xian-Lei (1); Zhao, Zhong (1); Liu, Xiang-Hua (1) 2006, 27 (10):  1102-1105.  DOI: - Abstract ( 215 )   HTML   PDF (260KB) ( 673 )   Investigates how to control reasonably the slab discharging time for plate rolling line to meet the requirements for scheduling a multi-slab alternate rolling process. Describes the typical layout of a single-stand plate rolling line and according to the scheduled rolling rhythm for the process, the time interval between two rolling operations is given. The conveying time after slab discharging is calculated according to the layout of rolling line, with the remaining time after discharging also calculated. A limit value is set up for the remaining time to consider unexpected influencing factors, which can be readjusted in actual operation to optimize the control effect of slab discharge time. References | Related Articles | Metrics

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Ni-based alloy cladding on copper crystallizer surface by laser Liu, Fang (1); Liu, Chang-Sheng (1); Tao, Xing-Qi (2); Chen, Sui-Yuan (1) 2006, 27 (10):  1106-1109.  DOI: - Abstract ( 327 )   HTML   PDF (425KB) ( 683 )   Copper crystallizer surface was clad with Ni-based alloy by a 5 kW-CO2 laser, and the microstructure and mechanical properties of the cladding were analyzed. The powdered Ni1015 alloy was used as cladding material because its composition is similar to that of the copper plate of crystallizer. The alloy was deposited on Cu substrate by virtue of plasma spraying, then remelted by a high-energy density laser at high scanning speed. By using OM, SEM and microhardness tester, the microstructural morphology/composition and microhardness distribution on the cross-section of the cladding were given. The cladding shows smooth and uniform surface and combines metallurgically with Cu substrate, of which the average microhardness is 270HV0.05, about 3.2 times as high as that of Cu substrate (85HV0.05). The results showed that in the testing the optimal process parameters of the laser cladding used are that the laser energy density equals 1.58 × 102 kW/cm2 and laser scanning speed equals 3-4 mm/min. References | Related Articles | Metrics

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Composition optimizing of lab-prepared refining slag for LF Meng, Jin-Song (1); Jiang, Mao-Fa (1); Wang, De-Yong (1); Liu, Cheng-Jun (1) 2006, 27 (10):  1110-1113.  DOI: - Abstract ( 250 )   HTML   PDF (118KB) ( 1299 )   A model of quadratic orthogonal regression design was designed to investigate the influences of w(CaO)/w(SiO2) and mass fraction of Al2O3 and CaF2 in refining slag on the desulphurization in LF. The results showed that, in the slag if FeO and MgO contents are 0.5% and 9%, respectively, the desulphurization rate increases then decreases with the increasing w(Ca0)/w(SiO2) value whose change will affect the influence of Al2O2, CaF2 content on the desulphurization rate. The main reason is the change in the useful CaO content in refining slag. In addition, the desulphurization rate increases obviously with increasing slag volume and decreasing FeO content. In the experiment the optimum slag composition was found to be w(CaO)/w(SiO2):9-11, w(Al2O3):27%-29%, w(MgO):9%, w(CaF2):8%-10% and w(FeO):less than 0.5%. References | Related Articles | Metrics

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Effects of raw materials composition and Ar flux on SiC powder synthesized from iron ore tailings Zhang, Shu-Hui (1); Yang, He (1); Xue, Xiang-Xin (1); Wang, Dong-Shan (1) 2006, 27 (10):  1114-1117.  DOI: - Abstract ( 212 )   HTML   PDF (197KB) ( 590 )   The effects of raw materials composition and Ar flux on the phase composition and microstructure of SiC powder synthesized from iron ore tailings were studied by means of XRD, SEM and EDX (energy dispersive X-ray). The results showed that the main phase of product samples is β-SiC with FexSiy phase as impurity, where the SiC is mostly in columnar form. The relative content of SiC in samples increases gradually with the increasing mole ratio of SiO2 to C. When the ratio is 4, the relative content of SiC reaches the maximum (about 82 %), then SiC content decreases if the ratio exceeds 4. On the other hand, the relative content of SiC decreases with increasing of Ar flux. References | Related Articles | Metrics

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Steel deoxidation and non-metallic inclusion control using AlMnCa alloy Zhan, Dong-Ping (1); Zhang, Hui-Shu (1); Li, Shu-Chuan (1); Jiang, Zhou-Hua (1) 2006, 27 (10):  1118-1121.  DOI: - Abstract ( 222 )   HTML   PDF (1325KB) ( 594 )   Experiments for deoxidation of low-carbon and low-silicon steel and control of non-metallic inclusion were done for 3 heats at 1873 K in a φ70 mm × 100 mm MgO crucible put into MoSi2 resistance furnace, with AlMnCa alloy used as deoxidant. The results showed that after deoxidized with 1# AlMnCa alloy, the dissolved oxygen and total oxygen content in the steel are both the lowest and the endpoint total oxygen is 37 × 10-6, and most inclusions in the steel are spherical CaO-containing compounds. However, after the steel was deoxidized by AlMnFe alloy, most inclusions are Al2O3 or Al2O3-MnO compounds among which only a small part is spherical. In the final steel 89.1% of inclusion size is less than 10 μm with none bigger than 50 μm. Then, 6 heats of industrial deoxidation tests for TGD07 steel were done in an 25 t LD converter with 1# AlMnCa alloy, and the results showed that the mean oxygen content in molten steel is 23.8 × 10-6 even down to 8 × 10-6. The average yield strength, tensile strength and elongation percentage of the test steel are increased by 19.2 MPa, 26.2 MPa and 0.55%, respectively, compared with that of the not test steel. References | Related Articles | Metrics

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Mathematical model of temperature field for baosteel new No.4 blast furnace lining and heat transfer analysis Zhang, Wei-Jun (1); Wu, Xue-Qi (1); Chen, Hai-Geng (1); Jiang, Hua (2) 2006, 27 (10):  1122-1125.  DOI: - Abstract ( 206 )   HTML   PDF (417KB) ( 1052 )   A three-dimensional mathematical model of temperature field is developed for the Baosteel new No.4 blast furnace lining, to which various boundary conditions are given to express relevant heat transfer processes. The model is used to analyze the temperature field distribution on the furnace lining and discuss the influences of the temperatures at which the slag skull forms and comes off in furnace and the thermal load due to cooling on the temperature field of furnace lining. The results show that the vulnerable zone of lining refractory and formation zone of slag skull are in a 100 mm range on lining's inner surface from the middle/lower part of furnace stack and bosh to the front-end of cooling plate. And a stable slag skull layer is easy to form when the furnace gas temperature is between 1300°C and 1450°C, while the temperature is over 1450°C the formation and stability of slag skull depend on the thermal load due to cooling in the range. To ensure the service life of copper cooling plate as long as possible, the minimum cooling water flow rate should be kept not less than 6 t/h. References | Related Articles | Metrics

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Effect of relative density on compressibility of Al-Si closed-cell aluminum foam Yu, Hai-Jun (1); Yao, Guang-Chun (1); Li, Bing (1); Wang, Yong (1) 2006, 27 (10):  1126-1129.  DOI: - Abstract ( 218 )   HTML   PDF (238KB) ( 770 )   A quasi-static compression test was carried out for Al-Si closed-cell aluminum foam of different relative densities, which was prepared by melt transferring-foaming process. The quasi-static mechanic behavior or deformation mechanism of the tested material due to compression was studied. The effect of relative density on the compressibility of Al-Si closed-cell aluminum foam was analyzed microscopically. The results show that the process of Al-Si closed-cell aluminum foam under compression presents obviously the characteristics of compressive deformation of brittle materials, i.e., a process from linear elasticity to friable collapse and finally to densification. The mechanic properties of Al-Si closed-cell aluminum foam is affected obviously by its relative density. Its compressive strength and Young's modulus both increase with increasing relative density. All these from test conform well with the results calculated theoretically. References | Related Articles | Metrics

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Preparation of lithium vanadium oxide and its electrochemical performance Liu, Li-Ying (1); Tian, Yan-Wen (1); Zhai, Yu-Chun (1); Xu, Cha-Qing (1) 2006, 27 (10):  1130-1133.  DOI: - Abstract ( 393 )   HTML   PDF (232KB) ( 1134 )   Lithium vanadium oxide, as cathode material for Li-ion battery, was synthesized by non-molten solid-state reaction with Li2CO3 and NH4VO3 as raw materials. The main reaction mechanism was determined by TG-DTA and XRD tests. XRD results indicate that material calcined at 580°C for 10 h has well-developed layered structure. Cyclic voltammogram tests indicate that insertion and extraction mechanisms of Li+ in Li1+xV3O8 are different, insertion proceeds step by step. Galvanostatic charge-discharge tests show that the initial discharge capacity and capacity retention after 55 cycles are 252.9 mAh·g-1 and 97.07%, respectively. AC analysis shows that the material has higher ion conductivity which is good for better electrochemical performance. References | Related Articles | Metrics

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Design on part of structural parameters of hydraulic rock drill Tian, Wen-Yuan (1); Hu, Ming (1); Zhu, Chun-Xia (1); Cai, Guang-Qi (1) 2006, 27 (10):  1134-1137.  DOI: - Abstract ( 301 )   HTML   PDF (222KB) ( 841 )   The operating principle of hydraulic impact mechanism with double-chamber oil scavenger is introduced with the formula of its piston s moving velocity given. To minimize the energy loss due to piston shoulder in sealing section, the formula to calculate the gap between piston and inner surface of cylinder block and oil sealing length are provided. Analyzing the energy loss due to oil distributing valve, the equation to calculate the moving distance of distributing valve is derived so as to determine the moving distance of valve core. An exemplification is presented to apply the calculation results to the YYT30 hydraulic rock drill we designed, and the test result indicated that total impact efficiency of the hydraulic rock drill comes up to 50%. The correctness of such design is thus verified. References | Related Articles | Metrics

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Fault diagnosis based on rough sets and C4.5 decision tree Wang, Qing (1); Ba, De-Chun (1); Meng, Xiang-Zhi (1) 2006, 27 (10):  1138-1141.  DOI: - Abstract ( 240 )   HTML   PDF (1173KB) ( 501 )   It was found that the precision and speed of fault diagnosis is unsatisfied due to large-scale repeating data and redundant attributes in information system (decision table) during practical applications. To solve the problem, a new model based on rough sets and decision tree C4.5 is presented. The theory of rough sets as a new mathematical tool is strong at dealing with incomplete and uncertain information and used to discretize and reduce the initial sample sets, while the C4.5 decision tree is used to learn quickly the reduced decision tables and form a tree classifier. An example is given to show the whole fault diagnosis process of RH-KTB vacuum metallurgical system by use of the new model. References | Related Articles | Metrics

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AHP-based vendor evaluation in combination with FCE Zhang, Zhen (1); Yu, Tian-Biao (1); Liang, Bao-Zhu (2); Wang, Wan-Shan (1) 2006, 27 (10):  1142-1145.  DOI: - Abstract ( 947 )   HTML   PDF (376KB) ( 4108 )   To prevent the result of the vendor evaluation just by AHP from individual subjective judgment and favoritism, a new approach to vendor evaluation is proposed combining AHP with FCE. In the new approach AHP is used to determine the weights of evaluation indices for all vendors, while FCE is introduced to process the information relevant to vendor evaluation. A mathematical model is therefore developed for fuzzily comprehensive evaluation and it is used to evaluate several vendors for a certain automobile manufacturer. References | Related Articles | Metrics

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Chemical embedding immobilization technique of micrococcus sp. used in contaminated surface water remediation Xu, Xin-Yang (1); Zhang, Yi (1); Li, Hai-Bo (2); Li, Pei-Jun (2) 2006, 27 (10):  1146-1149.  DOI: - Abstract ( 258 )   HTML   PDF (182KB) ( 753 )   According to the characteristics of contaminated surface water, a strain of Micrococcus sp. that could remove CODCr efficiently was picked out from the slowly flowing oil-polluted riverbed sludge in Liaohe Oil Field, and then it was immobilized by chemical embedding technique. Through the conditional tests of immobilizing parameters, an improved co-immobilization technique with PVA and sodium alginate was determined, and the immobilizing gel was made of 10.5% PVA, 0.5%Na·Alg, 3% activated carbon and traces of auxin. Experimental results showed that the Micrococcus sp. immobilized in such a way has the ability to remove 70.9% CODCr in contaminated surface water after 96 hours, i.e., 33.6% higher than the removal rate by free thalli. References | Related Articles | Metrics

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Formulation of domestic ecological footprint indicator and its application Gu, Xiao-Wei (1); Wang, Qing (1); Wang, Jun (1) 2006, 27 (10):  1150-1153.  DOI: - Abstract ( 260 )   HTML   PDF (316KB) ( 649 )   A new indicator, domestic ecological footprint, is formulated for measuring aggregate national environmental pressure based on the ecological footprint method. The indicator is applied to China for the period of 1961-2003. The domestic ecological footprint, ecological carrying capacity, and domestic ecological deficit are calculated. The historical profile, trend as well as the composition of China's environmental pressure are analyzed and the key problem indicated. The relationship between the national environmental pressure and the economical development is investigated. Results show that the ecological system of China has been overburdened since the beginning of 1970s, its domestic ecological footprint in 2003 reached 2.8 billion global hectares. This indicates that the fast economic growth and industrialization have been powered by high consumption of domestic ecological resources, and energy and agriculture are the key issues that must be addressed to turn the economy on a sustainable development track. References | Related Articles | Metrics

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Degradation of polycyclic aromatic hydrocarbons in soils by immobilized microorganisms Wang, Xin (1); Li, Pei-Jun (2); Song, Shou-Zhi (1); Verkhozina, V.A. (3) 2006, 27 (10):  1154-1156.  DOI: - Abstract ( 315 )   HTML   PDF (143KB) ( 770 )   Microorganisms were immobilized by chemical embedding technique. Three strains were immobilized both separately and jointly to degrade pyrene and benzo(a)pyrene in soil. The results showed that the degradation effect on soil contaminants by immobilized microorganisms was better than that by free ones, and the degradation efficiency of immobilized strain-mixture is higher than immobilized single strain. After immobilized for 96 h the strain-(2-9)-mixture provided a high degradation effect, i.e., the pyrene and benzo(α) pyrene were degraded at rate of 61.8% and of 34.9%, respectively. Sampling at different times showed that degradation of pyrene was faster than that of benzo(α) pyrene, since pyrene has leas benzene rings. The results as above can offer a certain theoretical basis for the application of immobilized microorganisms in bioremediation of soils contaminated with organic compounds. References | Related Articles | Metrics

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Influences of different sand-fixation plants on biological activity of soil Cao, Cheng-You (1); Teng, Xiao-Hui (1); Chen, Jia-Mo (1); Cui, Zhen-Bo (1) 2006, 27 (10):  1157-1160.  DOI: - Abstract ( 485 )   HTML   PDF (865KB) ( 607 )   Pinus sylvestris var. rnongolica, Caragana microphylla, Hedysarum fruticosumn and Artemisia haloderidron are widely used in stabilizing shifting sand dune in the semi-arid Horqin sandy grassland of north China. The objective of this study is to reveal how the 22-age plant communities of the above 4 species affect the biological properties of sandy soil quality. Soil samples were taken from each and every plant community at 3 depths (0-10, 10-20, 20-30 cm). The results showed that all the 4 species of plants improve greatly the organic C and total N in soil with microbial biomass accumulated much more and soil enzyme activity improved. Among the 4 plant species, C. microphylla has the highest ability to improve soil biological properties, of which the C and N contents in soil microbial biomass and the activities of phosphataese, urease, protease and dehydrogenase are all higher than those in the other three plants. The C. microphylla thus shows the strongest adaptability to sandy environment and is available to be recommended for wide use in fixing moving sand dune in the semi-arid region. References | Related Articles | Metrics

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Copper enrichment from contaminated soil by alfalfa and its physiological response Wang, Wen-Xing (1); Cao, Cheng-You (1); Cui, Zhen-Bo (1); Xu, Shu-Kun (1) 2006, 27 (10):  1161-1164.  DOI: - Abstract ( 258 )   HTML   PDF (243KB) ( 1144 )   Pot experiments were conducted to study how the Cu-contaminated soil affects the biomass, Cu accumulation, chlorophyll and free praline contents of alfalfa (Medicago sativa L.). Different Cu amounts were added into soil to form 10 Cu concentrations (l-400 mg·kg-1 soil) as contamination indices, according to the Chinese soil environment equality standard (CSEES). The relationship among chlorophyll, free praline and Cu enrichment in alfalfa was discussed. The results showed that the changes in chlorophyll contents and free proline contents are in line with that in biomass and Cu accumulation in alfalfa, respectively. Chlorophyll content increases with the increasing Cu concentration in soil and then decreases when Cu concentration is 30 mg·kg-1. The free praline content in alfalfa when the Cu addition is higher than 10 mg·kg-1 increases significantly in contrast with that in control tests(P &le 0.05). The Cu accumulation amount in alfalfa in the roots is significantly greater than that in its aboveground parts, and the total Cu enriched in alfalfa when Cu addition is 400 mg·kg-1 is up to 617 μg per pot, about 12 times as much as that in control tests. It reveals that alfalfa is indeed a potential plant for the phytoremediation of Cu-contaminated soil. References | Related Articles | Metrics

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Experimental study on light-weight steel frames with different semirigid joints Xu, Ling (1); Zhu, Fu-Sheng (1); Li, Xiao-Long (1) 2006, 27 (10):  1165-1168.  DOI: - Abstract ( 268 )   HTML   PDF (348KB) ( 648 )   The experiments of light-weight steel frames with four types of different semirigid joints were carried out. The characteristics and influencing factor on the bearing capacity, rotational stiffness and ultimate rotatability of steel frames with different semirigid joints are discussed, based on the experimental result. Analyzes the influences of end-plate/T-beam thickness and web ribbings of column on bearing capacity, rotational stiffness and ultimate rotatability of semirigid joints. The results show that the light-weight steel frames in form of semirigid connection with ribs are of high bearing capacity and ductility, and the end-plate connection with web ribbings provided for columns makes the semirigid joints better for light-weight steel frames. The thickness of a flange of a T beam has a few contributions at the bearing capacity of connection, but the web does have remarkable contribution. The slippage between components of joints plays an important part at its mechanical behavior, and more attention should be paid in design. References | Related Articles | Metrics

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Choosing stock replenishment/delivery model in view of different service levels as customers required Ji, Shou-Feng (1); Fu, Cheng-Jun (1); Huang, Xiao-Yuan (1) 2006, 27 (10):  1169-1172.  DOI: - Abstract ( 249 )   HTML   PDF (108KB) ( 915 )   Considering that customers' waiting cost reflects the service level they require to a certain extent, two typical stock replenishment/delivery models are discussed for VMI (vendor managed inventory) to meet different demands when the service level is required differently by customers. Both models take the integrated stock replenishment/delivery models, but one is based on time and the other one based on quantity. Discusses how a vendor schedules his stock replenishment/delivery strategy in accordance to the service levels the customers required to maximize their satisfaction with his own benefits optimized. An approach to choosing such a strategy is proposed, which is computed utilizing the MATLAB simulation software. References | Related Articles | Metrics

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Coordination mechanism for supply chain based on two-hierarchical programming theory Zhang, Cui-Hua (1); Ge, Liang (1); Fan, Yan (1); Yu, Hai-Bin (2) 2006, 27 (10):  1173-1176.  DOI: - Abstract ( 198 )   HTML   PDF (1196KB) ( 613 )   The basic models for supplier profit and producer cost and further the total cost model for supply chain are developed. The two-hierarchical programming theory is applied to the interactive coordination between supplier and producer in definite demand where the producer is at upper level and the supplier at lower level and they are interactive in decision-making. Then, a proper model of supply chain coordination is set up using hierarchical programming theory. Simulation results indicate that the solution based on hierarchical programming theory to the problem of supply chain optimization has lower cost and better achievement than the supply chain operation in simple way. In addition, the value of the control variable in supply chain, i.e., penalty coefficient k is discussed, thus verifying further the important role the two-hierarchical programming theory played in the coordination of supply chain. References | Related Articles | Metrics

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- - 2006, 27 (10):  1177-1180.  DOI: - Abstract ( 228 )   HTML   PDF (114KB) ( 774 )   - References | Related Articles | Metrics