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15 February 2009, Volume 30 Issue 2 Previous Issue    Next Issue
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Adaptive neural network control of discrete-time nonlinear systems with triangular-form Zhai, Lian-Fei (1); Chai, Tian-You (1) 2009, 30 (2):  153-157.  DOI: - Abstract ( 267 )   HTML   PDF (303KB) ( 599 )   For a class of multi-input-multi-output (MIMO) discrete-time nonlinear systems with triangular form control inputs, an adaptive neural network control is proposed via backstepping. Due to the non-affine form of the control inputs, feedback linearization method can not be used to design control system. Therefore, implicit function theorem is firstly exploited to assert the existence of the ideal control inputs, which can compel the system outputs to track their desired trajectories, and then ideal control inputs are constructed. By using high-order neural networks to approximate the ideal control inputs, an adaptive neural network control is developed via backstepping design. All signals of the closed-loop system are proved to be semi-globally uniformly ultimately bounded under the proposed control, while the effectiveness of the proposed control is illustrated by simulations. References | Related Articles | Metrics

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Fuzzy hyperbolic H∞ filter for a class of nonlinear stochastic systems Xie, Xiang-Peng (1); Zhang, Hua-Guang (1) 2009, 30 (2):  158-161.  DOI: - Abstract ( 298 )   HTML   PDF (1197KB) ( 687 )   Studies the problem of fuzzy H∞ filter for Ito-type nonlinear stochastic systems. With the fuzzy hyperbolic rule base defined, the stochastic fuzzy hyperbolic model (SFHM) is developed. The superiority of SFHM over Takagi-Sugeno (T-S) fuzzy model in practice is mainly that no identification of preconditional structure and complete parameter space are needed, especially SFHM costs obviously less than T-S fuzzy model in computation when a lot of fuzzy rules are needed. Furthermore, based on SFHM, the H∞ filter is designed to transform the second-order nonlinear Hamilton-Jacobi inequality problem which is difficult to solve in the design of nonlinear stochastic H∞ filter into the problem of linear matrix inequality, and the fuzzy hyperbolic H∞ filter is therefore given by solving the linear matrix inequalities instead. Simulation example is provided to illustrate the effectiveness of the proposed approach. References | Related Articles | Metrics

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On the navigation system based on CCD for smart car Zhang, Yun-Zhou (1); Shi, En-Yi (1); Wu, Cheng-Dong (1); Qin, Zhao-Bing (1) 2009, 30 (2):  162-165.  DOI: - Abstract ( 475 )   HTML   PDF (312KB) ( 1005 )   At present most navigation information on the pavement on which a smart car is traveling is acquired by camera. A navigation module is therefore developed, for which how the CCD video signal is acquired and processed are described. Considering the effect of the change of ambient light on the navigation system of the car, an image processing algorithm with adaptive dynamic threshold is proposed to track the change of ambient light and provide an anti-jamming way for the navigation system with short operating time required. The problem that a running car deviates from planned route because of changes of ambient light and raceway can thus be solved efficiently. As a result of test and actual competition, the navigation system showed its intelligence and anti-jamming ability, i.e., the navigation module is effective. References | Related Articles | Metrics

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Human face recognition based on fast wavelet transform and FLD Wang, Xiao-Zhe (1); Li, Chen-Yang (1); Wu, Cheng-Dong (1) 2009, 30 (2):  166-168+183.  DOI: - Abstract ( 437 )   HTML   PDF (309KB) ( 895 )   A human face recognition algorithm based on fast wavelet transform (FWT) and Fisher's linear discriminant (FLD) is presented to meet the requirement of quick face recognition at high rate. In the algorithm the Haar wavelet with scales of 1 and 2 is applied separately to the decomposition of typical human face, then the features are extracted from the original image and the images decomposed on the scales of 1 and 2 by FLD. Consequently, the features extracted are recognized by nearest neighbor classifier. A simulation of the algorithm proposed was done on the basis of ORL (Olivetti Research Lab) face database, and the results showed that the algorithm is able to recognize quickly with high recognition rate. References | Related Articles | Metrics

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Research and application of the feedforward-AGC system in hot strip rolling mills Zhong, Yun-Feng (1); Tan, Shu-Bin (1); Xu, Xin-He (2) 2009, 30 (2):  169-171.  DOI: - Abstract ( 283 )   HTML   PDF (212KB) ( 1052 )   Either RF-AGC or Mon-AGC of AGC (automatic gauge control) model to the 1580 hot strip rolling mill belongs to a feedback control system. Time lag is therefore inevitable to the readjustment of rolling gap, thus resulting in the constraint on improving the strip gauge precision. The normal feedforward idea about tandem cold mills was introduced into hot strip rolling to develop a feedforward AGC model via the calculated strip thickness from the exit preceded stand, which was taken as the inspected gauge in feedforward control and processed by tracking shift. In this way the rolling gap can be readjusted in time according to gauge fluctuation so as to attain the goal of precontrol. As a result, the thickness gauge precision of rolling strip is improved obviously. References | Related Articles | Metrics

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Partial least squares regression based on transformation of fuzzy basis functions and its application to soft sensor Jia, Run-Da (1); Mao, Zhi-Zhong (1); Chang, Yu-Qing (1) 2009, 30 (2):  172-175.  DOI: - Abstract ( 282 )   HTML   PDF (388KB) ( 834 )   To model the nonlinear system and get rid of the limitation of existing nonlinear partial least squares (PLS), a nonlinear PLS algorithm based on the transformation of fuzzy basis functions is presented. The nonlinear relationship between independent and dependent variables are changed into linear one by transforming the fuzzy basis functions. Then, the PLS algorithm is used to get the regression parameters of the transformed independent and dependent variables so as to efficiently solve the problems of dimension increasing and multi-collinearity caused by the transformation of fuzzy basis functions. The model thus developed has the goodness of fit and is available to restrain the noise in process data. Simulation test results verified the superiority of this method to other nonlinear PLS methods, and it has been applied to the soft sensing modeling for component contents in hydrometallurgy extraction process with satisfactory prediction results obtained. References | Related Articles | Metrics

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Heart rate measurement based on fluttering signal from human body Jin, Jing-Jing (1); Wang, Xu (1); Yang, Dan (1) 2009, 30 (2):  176-179.  DOI: - Abstract ( 804 )   HTML   PDF (511KB) ( 1995 )   The fluttering signal due to synchronous heartbeat from human body is used to measure heart rate where the body fluttering signal is caused by the heart which pumps blood round the body. The rhythm of the signal associates inevitably with heart rate and can be detected at the vertebral axis of the body by sensitive force sensor. The signal is so weak and easy to be jammed that the sensor circuit and signal processing circuit should be designed specially, from which the method to detect the signal is described. The fluttering signal acquired initially should be preprocessed for denoising, then the mode maximum algorithm is used to find out the peak point of every and all cardiac cycles, thus obtaining the heart rate. To evaluate the exactness of the heart rate thus measured, a single channel electrocardiosignal should be acquired synchronously along with acquiring the fluttering signal from human body as reference. Test result showed that such a heart rate measurement based on human body fluttering signal can get effective outcome. References | Related Articles | Metrics

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Medical image retrieval based on contourlet transform Zhang, Qi-Dong (1); Gao, Li-Qun (1); Wu, Jian-Hua (1); Wang, Xiao-Man (1) 2009, 30 (2):  180-183.  DOI: - Abstract ( 270 )   HTML   PDF (348KB) ( 960 )   Considering the characteristics of medical image, a novel medical image retrieval algorithm based on texture is proposed. Combining with the multi-scale and multi-directional characteristics of non-separable and directional filter banks, the contourlet transform can effectively capture the contours of an image and depict them sparsely. The algorithm proposed takes fully the advantage of statistical attribution of image's contourlet transform coefficients to form the eigenvector for depicting textural feature and retrieval. Retrieval tests were carried out for a CT image database with the algorithm, and the results were compared with that by the retrieval algorithm based on Harr wavelet transform. It was found that the precision of retrieval in contourlet transform domain is higher than that in wavelet transform domain, thus verifying the higher retrievability of the algorithm. References | Related Articles | Metrics

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Simulation analysis of quality factor of superconducting receiving coil for MRI system Wu, Chun-Li (1); Xiao, Jing-Kui (2); Zhang, Li (3); Wang, Jin-Xing (4) 2009, 30 (2):  184-186+199.  DOI: - Abstract ( 269 )   HTML   PDF (546KB) ( 1014 )   To investigate the relationship between the quality factor of a receiving coil made from specified superconducting material and resonant frequency in MRI system, a simulation model was developed using the HF software Ansoft HFSS and according to the size of the experimental setup of Bi2223/Ag superconducting receiving coil. Analyzing the frequency characteristics of resonance loop, it was found that the simulation results are basically in accord with the experimental results. The relationships between the quality factor of superconducting receiving coil and different resonant frequencies were obtained by adjusting the resonance capacitance of resonance loop to change its resonant frequency. The results indicated that only if the RF receiving coil is made from superconducting material and operating at low frequency, the signal noise ratio (SNR) in MRI system can be effectively improved. References | Related Articles | Metrics

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An improved lung segmentation algorithm for chest CT images Meng, Lu (1); Zhao, Da-Zhe (2); Jia, Tong (1); Zhao, Hong (2) 2009, 30 (2):  187-190.  DOI: - Abstract ( 447 )   HTML   PDF (908KB) ( 708 )   To segment accurately the pathologic lung images, the conventional segmentation algorithm for lung was analyzed and improved by introducing the wavelet transform and mathematical morphology into the algorithm, i.e. an image was decomposed via wavelet transform, then each and all of its components after decomposition were mended in different ways through mathematical morphology. Morphologically the closed and open operation should be done for LF and HF components, respectively, thus modifying the basic traits of an image on a proper scale without detailed traits obscured and, after image restructuring, obtaining the ideal lung region. The improved algorithm was applied to the segmentation of 36 sets of clinical HRCT data provided by hospitals, and its results were compared with those from manual segmentation and conventional algorithm. It was found that the improved algorithm can provide accurate segmentation so as to make the average sensitivity of lung segmentation higher. References | Related Articles | Metrics

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Segmentation of trachea and bronchus based on improved region growing method Jiang, Hui-Yan (1); Zhang, Ye (1) 2009, 30 (2):  191-194.  DOI: - Abstract ( 344 )   HTML   PDF (531KB) ( 1157 )   Considering the tree-like traits of trachea and bronchus, an improved region growing method is presented for their segmentation. Getting the initial region of trachea from the top of CT images, the region growing method is improved taking advantage of the correlation between the geometrical and gray-level characteristics of trachea or bronchus in adjacent CT images. Then, the improved method is applied to the search for other regions of trachea and bronchus step by step along the tree-like paths in 3D space and, consequently, all of the data of trachea and bronchus are obtained. With its high automatability, the method fits the segmentation of not only the trachea and bronchus but also the other small regions such as bones and blood vessel system. References | Related Articles | Metrics

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New routing algorithm of structured peer-to-peer overlay networks Tan, Zhen-Hua (1); Cheng, Wei (1); Chang, Gui-Ran (2); Gao, Xiao-Xing (1) 2009, 30 (2):  195-199.  DOI: - Abstract ( 259 )   HTML   PDF (292KB) ( 986 )   In order to improve the routing algorithm efficiency of the structured peer-to-peer overlay networks, a new DHT-based CSSP algorithm was presented with lower maintenance over head and longer route. A short routing table was defined at constant level to record L cache nodes' fingers, one super node finger and one successor node finger. The algorithms maintaining the route table for node entering/exiting were presented, as well as the distributed election algorithm for super node that could cache all of the nodes. And the cache-nodes, super-node and successor-node ensure the high performance of the CSSP. Compared to the performance of such typical algorithms as Chord and Pastry, the CSSP algorithm greatly improves the performance in regard to routing table maintaining, routing hops, fault-tolerance and network churning when nodes are entering or exiting the CSSP P2P system. Simulations and analysis showed that the CSSP is an efficient route algorithm though some problems are to be studied further. References | Related Articles | Metrics

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Effect of TMCP parameters on microstructure and mechanical properties of high-strength structural steel Lan, Hui-Fang (1); Du, Lin-Xiu (1); Liu, Yan-Chun (1); Liu, Xiang-Hua (1) 2009, 30 (2):  200-204.  DOI: - Abstract ( 696 )   HTML   PDF (781KB) ( 1822 )   Discusses the effects of TMCP parameters, i.e. the processing parameters, on the microstructure and mechanical properties of high-strength structural steel. And the strengthening/toughening mechanism of the steel is investigated by virtue of optical microscope, SEM (scanning electron microscope) and EBSD (electron backscattered diffraction). By choosing properly the parameters of the two-stage controlled rolling and accelerated cooling process, the high strength structural steels were obtained coming up to China's National Standards Q690, Q620 and Q550 as included in GB/T16270-1996. The regression equations describing relationship between such processing parameters as finish rolling/cooling temperature, cooling rate and mechanical properties are thus given, and how those parameters affect the microstructure and mechanical properties are analyzed. The results showed that the steel plates can be up to the standard Q550 if the finish rolling temperature θFR=870-880°C, cooling rate vC=15-20°C/s and finish cooling temperature θFC=570-600°C; up to Q620 if θFC=500-570°C with other conditions unchanged; up to Q690 if vC=35-40°C/s and θFC&asyum;550°C with θFR unchanged. References | Related Articles | Metrics

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Rolling process investigation on upgrading Q390C continuous casting slab to Q460qE plate Deng, Wei (1); Zhao, De-Wen (1); Qin, Xiao-Mei (1); Liu, Xiang-Hua (1) 2009, 30 (2):  205-207+212.  DOI: - Abstract ( 298 )   HTML   PDF (831KB) ( 587 )   The Nb+V+Ti microalloyed Q390C continuous casting slabs were upgraded successfully to Q460qE via TMCP (thermo-mechanical controlled process) with all mechanical properties up to the relevant plate standard. The main parameters of rolling schedule in two pilot tests were as follows: rough rolling temperature range 1000-1100°C; finishing rolling onset at (890±10)°C and terminating at (820±10)°C; starting temperature for cooling is at (780±10)°C and ending at (630±10)°C, cooling rate about 12°C/s and the total reduction in finishing section not less than 60%. The cumulative heavy reduction in the austenite unrecrystallized region benefits the formation of high-density austenite grain boundary, thus increasing the ferrite nucleation rate with grain refining. Furthermore, it was found that the surface structure of the steel plate thus rolled is composed of tiny polygonal ferrite plus bainite and that the structure of intermediate layer is composed of ferrite plus pearlite. Such a structure can provide high tensile strength and impact toughness. References | Related Articles | Metrics

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Phenomenological behavior of recrystallized nucleation in DZ40M alloy Zhao, Yang (1); Wang, Lei (1); Yu, Teng (1); Liu, Yang (1) 2009, 30 (2):  208-212.  DOI: - Abstract ( 271 )   HTML   PDF (632KB) ( 901 )   The relationship between recrystallized nucleation location and grain orientation after nucleation in DZ40M alloy was investigated by SEM and EBSD. The results showed that after the deformation by indentation the recrystallized grains during annealing nucleate around the primary carbides and interdendritically in <112> orientation and <110> orientation, respectively. The formation of nucleus of recrystallization in DZ40M alloy could be prevented by the secondary carbides M23C6 precipitated at grain/subgrain boundaries and dislocation positions. When the annealing temperature is below 1423 K, the number of M23C6 precipitates increases with small size and spacing to restrain the recrystallized nucleation and decrease its rate. References | Related Articles | Metrics

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Surface quality and structure of 7050 aluminum alloy by low frequency electromagnetic hot-top casting Wang, Xiang-Jie (1); Zuo, Yu-Bo (1); Zhao, Zhi-Hao (1); Cui, Jian-Zhong (1) 2009, 30 (2):  213-216.  DOI: - Abstract ( 279 )   HTML   PDF (642KB) ( 652 )   A new hot-top casting mold was developed on the basis of conventional hot-top casting, and the low-frequency (LF) electromagnetic field was applied in the process of casting. The stable technological conditions for hot-top casting of φ500 mm 7050 high-strength aluminum ingots were gotten, i.e. smooth ingots were available, when electromagnetic frequency is 15 Hz with electromagnetic intensity 10000 At. The microstructure of ingot samples were observed by Leica DMI microscope. Experimental results showed that the LF electromagnetic field can improve the surface quality of ingot with grain refining and internal cracks suppressed, and the reasons why the quality of ingots are improved and the effect of LF electromagnetic field on the shape of melt cave were summarized. References | Related Articles | Metrics

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Photocatalytic reduction of Cr(VI) by sulfate modified titanium-bearing blast furnace slag Xue, Xiang-Xin (1); Lei, Xue-Fei (1); Yang, He (1); Duan, Pei-Ning (1) 2009, 30 (2):  217-220.  DOI: - Abstract ( 245 )   HTML   PDF (517KB) ( 871 )   Perovskite-type STBBFS (sulfate-modified titanium-bearing blast furnace slag) photocatalyst was prepared by the high energy ball milling process and calcination at 300°C for 2 h. The powdered catalyst was characterized by XRD, UV-vis absorption spectroscopy and SEM. It was found that the shapes of powder particles are irregular with an average particle size about 1.5 μm, and the catalyst has high light absorbability in UV range. Its photocatalytic activity was checked through the reduction rate of Cr(VI). The results showed that the perovskite-type photocatalyst STBBFS presents a higher catalytic activity in comparison to the commercial TiO2 catalysts, which can fully degrade the waste water where the Cr(VI) concentration is up to 20 mg/L under the 4 h irradiation by a 500 W MV mercury lamp. References | Related Articles | Metrics

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Effect of initial composition on (Ca, Mg)α′-sialon/BN powder synthesized from boron-rich slag Wu, Jun-Bin (1); Jiang, Tao (1); Xue, Xiang-Xin (1); Li, Jiang (1) 2009, 30 (2):  221-224+237.  DOI: - Abstract ( 271 )   HTML   PDF (528KB) ( 627 )   The (Ca, Mg) α′-Sialon/BN composite powder was synthesized by carbothermal reduction nitridation with boron-rich slag as main starting material, of which the composition is (Ca, Mg)xSi12-3xAl3x OxN16-x where x is ranging from 0.3 to 1.8. The effect of different x values on the phase composition and microstructure of synthesized products were investigated by XRD (X-ray diffraction), SEM (scanning electron microscope) and EDX (energy dispersive X-ray). The results showed that the content of α′-Sialon increases with increasing value of x and comes up to the maximum when x=1.4 but decreases when x value exceeding 1.4 with increasing AlN and a certain amount of 15R(SiAl4O2N4) found. The α′-Sialon grains presents long columnar grains when x≥1.4. References | Related Articles | Metrics

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Study on self-strength of calcium ferrite binding phase in sinter Li, Guang-Sen (1); Dou, Li-Wei (2); Shang, Ce (2); Shen, Feng-Man (1) 2009, 30 (2):  225-228.  DOI: - Abstract ( 282 )   HTML   PDF (528KB) ( 964 )   The self-strength of calcium ferrite binding phase in sinter and relationship between the fracture/compression strength and binding phase's composition were studied experimentally. Tested with the different mol ratios of CaO to Fe2O3 and the different contents of MgO, SiO2 and Al2O3, the fracture/compression strength of different binding phases was discussed. It is found that the highest fracture/compression strength is given when the ratio n(CaO):n(Fe2O3)=1:2, but the strength decreases when increasing MgO content. The appreciate content of SiO2 (<3wt%) will improve the strength of binding phase, while the strength of binding phase decreases with increasing Al2O3 content. References | Related Articles | Metrics

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Arrangement optimization of electro-slag remelting furnace based on finite element analysis of electromagnetic field Liu, Fu-Bin (1); Zang, Xi-Min (1); Jiang, Zhou-Hua (1); Geng, Xin (1) 2009, 30 (2):  229-232.  DOI: - Abstract ( 246 )   HTML   PDF (568KB) ( 573 )   Introducing the FEA software ANSYS in numerical simulation, the spatial distribution of magnetic field generated around a high-current conductor during electro-slag remelting was investigated. The calculated results showed that there are differences between maximum and minimum values of magnetic induction in a nonuniform distribution around electrode surface when return current happens, i.e. 35.22%, 13.26% and 5.8% for single, double and four connecting wire, respectively. Such differences result in uneven eddy current density on electrode surface, which will affect the electrode remelting rate. Taking the effect of magnetic field on remelting process into consideration, the symmetrically coaxial arrangement of the furnace is introduced to greatly decrease the disadvantages resulting from induced eddy current. To reduce extra loss of energy, erase sperromagnetism, and prevent spot-like segregation and current's stirring action, the coaxial arrangement of ESR furnace will be the trend of ESR furnace design. References | Related Articles | Metrics

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Preparation of CuInSe2 thin films by tri-source vacuum co-evaporation and their properties Shan, Yu-Qiao (1); Dang, Peng (1); Sun, Shao-Guang (1); Shan, Lian-Zhong (1) 2009, 30 (2):  233-237.  DOI: - Abstract ( 282 )   HTML   PDF (516KB) ( 746 )   The CuInSe2 (CIS) thin films were prepared by tri-source vacuum co-evaporation with the pure Cu, In and Se powder as the evaporation sources. The effects of substrate temperature and annealing process on the surface morphology, structure and optical electrical properties of the films were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible spectroscopy and Hall probe. The results showed that the absorption indices of the thin films deposited on the substrates at different temperatures are all high in visible light band and all the films have a (112) preferred orientation. The energy gap is 0.99 eV when the substrate is at 200°C. The CuInSe2 films are of single chalcopyrite structure when the substrate temperature is either 200°C or 300°C, and their resistance is 1.53 Ω/cm2 or 1.55 Ω/cm2 after annealing, respectively. References | Related Articles | Metrics

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Theoretical studies on fullerene C100 and its derivatives C100X4 Wang, Dong-Lai (1); Gu, Hui-Min (1); Shen, Hong-Tao (1); Zhai, Yu-Chun (1) 2009, 30 (2):  238-241.  DOI: - Abstract ( 262 )   HTML   PDF (367KB) ( 830 )   According to the B3LYP density functional theory, the 6-31 G* basis set was employed to study the equilibrium geometrics and electronic structures of six lower-energy isomers of fullerene C100 and its derivatives C100X4 (X=H, F, Cl, Br) which are based on lowest energy. The calculation results indicated that the D2 C100 isomer is of the most stable structure and the reactions of C100X4 (X=H, F, Cl) are all exothermic. The calculated results of vibration frequencies showed that the four structures of C100X4 (X=H, F, Cl, Br) molecules are all the stationary points on their potential energy surfaces. The C100 F4 is more stable in the molecular cluster investigated, and it is quite possible to be synthesized experimentally. References | Related Articles | Metrics

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On the settling performance of red mud from preroasted high-sulfur bauxite Lu, Guo-Zhi (1); Zhang, Ting-An (1); Bao, Li (1); Dou, Zhi-He (1) 2009, 30 (2):  242-245.  DOI: - Abstract ( 196 )   HTML   PDF (799KB) ( 633 )   The high-sulfur bauxite was preroasted in rotary tube furnace and muffle furnace to investigate the effect of roasting temperature on the settling performance of red mud digested from roasted high-sulfur bauxite. The changes in apparent morphology and phase composition were analyzed and discussed by SEM and XRD, as well as the changing mechanism of the settling performance of red mud. Experimental results indicated that preroasting process makes the apparent morphology of red mud looser and more porous and enables the geothite in bauxite ore to transform into hematite to improve the settling performance of red mud. The overloosened ore after roasting will cause the red mud to be excessively fine, thus making the settling performance of red mud poor to a great extent. Comparing the digested sludge from the preroasted ore in muffle furnace to the digested sludge from that in rotary tube furnace, the latter has better settling performance. References | Related Articles | Metrics

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Powder metallurgy-foaming process of rolled precursor for aluminum foam sandwich Zu, Guo-Yin (1); Zou, Ying (1); Li, Hong (1); Yao, Guang-Chun (1) 2009, 30 (2):  246-249.  DOI: - Abstract ( 242 )   HTML   PDF (493KB) ( 730 )   The precursors for aluminum foam sandwich (AFS) were made by rolling bonding, then they were further worked through powder metallurgy-foaming process to produce AFS. The foaming process was investigated to analyze the AFS microstructure and the different phases, as well as the effects of the foaming agent TiH2 particle size and the agglomeration of those particles on foam formation. The results showed that after foaming the bubble walls are mainly composed of the Al-Si eutectic phase Al3.21Si0.47, Ti and Ti3O, and microcrackes are more likely to take place around the large-size TiH2 particles with the expandable crack width over 100 μm. Furthermore, the sizes of the pores near the cracks are very small. Agglomeration of TiH2 particles during powder mixing and rolling may result in partial excessive driving force for foaming in AFS, thus enabling the large-size pores to form in AFS core after foaming. References | Related Articles | Metrics

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Effects of B3+ on luminescent properties of Tb3+/Eu2+-doped BaAl12O19 phosphors He, Ming-Rui (1); Xiao, Lin-Jiu (2); Tian, Yan-Wen (1); Chen, Yong-Jie (2) 2009, 30 (2):  250-253.  DOI: - Abstract ( 202 )   HTML   PDF (621KB) ( 618 )   The phosphors BaAl12O19:Tb and BaAl12O19:Eu were synthesized by sol-gel method, and the effects of B3+ doping on the crystal line structure and luminescent properties of them were studied. The results showed that B3+ doping doesn't affect the BaAl12O19 structure but improves their luminescent intensity. However, B3+ doping plays more obvious role in improving the luminescent intensity of BaAl12O19:Tb than in that of BaAl12O19:Eu and the effective B3+ doping dose for the former is obviously greater than that for the latter. The optimum B3+ doping doses are 50 mol% and 20 mol% for BaAl12O19:Tb and BaAl12O19:Eu, respectively. References | Related Articles | Metrics

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Study on the adsorption of trace Pb(II) on TiO2 nanoparticles Zhang, Xia (1); Zhao, Yue (1); Sun, Ting (1) 2009, 30 (2):  254-257.  DOI: - Abstract ( 196 )   HTML   PDF (406KB) ( 844 )   An efficient separation of the trace Pb(II) in waste water was carried out taking TiO2 nanoparticles as adsorbent and flame atomic absorption spectrophometer as detector to determine the concentration of Pb(II). The effects of the crystalline structure of TiO2 nanoparticles, pH values of solution, adsorbing time and initial concentration of Pb(II) on the adsorption rate were systematically studied, with the optimum adsorption conditions determined, i.e., pH=6.5, m(TiO2)=20 mg, ρ0(Pb(II))=18 mg·L-1, t=90 min. The relevant adsorption isotherm was then determined with the isotherm equation given on the basis of Freundlich formula. References | Related Articles | Metrics

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Dynamic behavior of elastic rotor system Wang, Zheng-Hao (1); Yuan, Hui-Qun (1); Li, Dong (1); Wen, Bang-Chun (1) 2009, 30 (2):  258-261.  DOI: - Abstract ( 209 )   HTML   PDF (631KB) ( 801 )   Considering the elasticity of stator and the elastic connection between rotor and stator, a dynamic model of rotor system was developed with the rub-impact fault and gyroscopic effect both coming to pass. Getting the system response through numerical integration, the effects of the mass ratio of stator to rotor and eccentric torgue ratio of the two disks on the system bifurcation and chaos were analyzed. The results showed that the main routes the system enters chaos are from the intermittent chaos and the period 3 then through the period-doubling bifurcation. The elasticity of this system restrains the response to chaos to a certain extent in comparison with the system supported rigidly. A conclusion is therefore drawn that the elasticity of stator will get the domain of chaos response and high-order critical speed decreased and greatly affect the high-order critical speed and resonance amplitude, but it slightly affects the low-order critical speed and resonance amplitude. References | Related Articles | Metrics

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Reliability model of cumulative fatigue damage of load-sharing parallel system Hao, Guang-Bo (1); Xie, Li-Yang (1); Li, Li (1); He, Xiu-Yun (1) 2009, 30 (2):  262-265+278.  DOI: - Abstract ( 331 )   HTML   PDF (889KB) ( 825 )   The conventional reliability model of parallel system is inadaptable to the parallel system where the load is transferred and shared. Analyzing the dependent failure and stepwise computing the reliability of a parallel system, the reliability model of cumulative fatigue damage of a load sharing parallel system is developed according to the total probability formula and Miner theory. Then, a simulative computation is done by the Monte Carlo method for the reliability of parallel system in which the service life of a component follows the Weibull distribution, with the explicit formula of system reliability deduced for the service life of a component that follows the logarithm normal distribution. As a result, a reliability model of cumulative fatigue damage for the parallel system under the action of varying stress is developed. References | Related Articles | Metrics

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Recognition based on composite characteristics and SVM for sucker rod's defects Sun, Hong-Chun (1); Xie, Li-Yang (1); Xing, Hai-Tao (2) 2009, 30 (2):  266-269.  DOI: - Abstract ( 268 )   HTML   PDF (459KB) ( 597 )   To improve the recognition rate of sucker rod's defects, the composite characteristics including both the characteristics of wavelet packet energy and peak-to-peak values in time domain were applied to the recognition in combination with the SVM based on small samples. The separability of the composite characteristics was proved better than that of the characteristics of single wavelet packet energy and the former can enhance the effectiveness of recognition to a certain extent by introducing the separability criterion based on the distance between classes. On the other hand, the pattern recognition of the sucker rod's defects was carried out with the one-to-one data classified SVM using lots of data, and the results revealed that the separability of composite characteristics is better than that of single wavelet packet energy, with smaller errors due to the generalization of defect recognition. References | Related Articles | Metrics

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Application of response surface methodology in sensitivity calculation of reliability Shi, Yan-Yan (1); Sun, Zhi-Li (1); Yan, Ming (2) 2009, 30 (2):  270-273.  DOI: - Abstract ( 256 )   HTML   PDF (233KB) ( 1393 )   A process of applying the response surface methodology (RSM) to the acquisition of the function in ultimate state, which is characterized with the quadratic polynomial response surface function, is briefly described. A new method is proposed to analyze the sensitivity of reliability via the function in ultimate state. An example is given to prove that the method proposed is available to the unknown function in ultimate state, with some formulae deduced. The function in ultimate state obtained by RSM, as a simple quadric polynomial, naturally includes the information on linear, quadratic and cross quadratic terms, thus making the sensitivity calculation of reliability easy to do and its accuracy very high. With the cracking due to thermal fatigue exemplified, the reliability without destabilized extension happening is calculated, as well as its sensitivity with different random variables. References | Related Articles | Metrics

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Study on improved fuzzy-PID composite control arithmetics and its applications Li, Li-Na (1); Liu, Hong-Yi (1); Luo, Zhong (1); Sun, Yi-Lan (1) 2009, 30 (2):  274-278.  DOI: - Abstract ( 278 )   HTML   PDF (456KB) ( 1544 )   An improved method is presented to get rid of disadvantages of conventional fuzzy-PID composite control after analyzing its control characteristics. The self-adaptive fuzzy-PID composite control is implemented via the fuzzy switching arithmetic based on trapezoidal membership function and the online self-tuning arithmetic with quantized and proportional factors based on variable universe and human simulating intelligence. With this improved method an intelligent temperature control system for PCR chip is performed to show its highly dynamic and stable traits, strong robustness and adaptability. Test results revealed that the improved controller is much better than conventional fuzzy-PID controller and simple fuzzy controller. References | Related Articles | Metrics

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Research on task allocation of process planning based on reinforcement learning and neural network Su, Ying-Ying (1); Wang, Wan-Shan (1); Wang, Jian-Rong (1); Tang, Liang (1) 2009, 30 (2):  279-282.  DOI: - Abstract ( 546 )   HTML   PDF (382KB) ( 2170 )   Aiming at the curse of dimensionality caused by prodigiousness of state-action space for Markov decision-making process model, a kind of Q learning method based on neural network was proposed. The Q value of a state-action pair during reinforcement learning was approached and stored by means of the high generalizability of BP neural network, then the optimal strategy based on Q learning for selection of action and a BP neural network model and algorithm for Q learning were designed. The algorithm proposed was applied to task allocation of process planning, with a simulation done by the software Matlab. The result indicated that it has a good performance and the capability of action approach, and the method enhances the applicability of reinforcement learning in task allocation. References | Related Articles | Metrics

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On the automatic route layout for connection of three pipeline terminals Bai, Xiao-Lan (1); Wang, Cheng-En (2); Zhang, Yu (1); Liu, Qiang (2) 2009, 30 (2):  283-286.  DOI: - Abstract ( 255 )   HTML   PDF (480KB) ( 852 )   Based on maze algorithm, an automatic route layout method is proposed for the connection of three pipeline terminals in design. With the grid pre-processing used to transform the actual space for pipeline layout into a grid space and the maze algorithm used to simulate the characteristics of wave propagation, the appropriate position of T-pipe is found out in either case with and without obstacles. Then, a backtracking is introduced according to relevant rules to determine the feasible routes which satisfy the constraint conditions and, by data processing, are transformed into the space for pipeline layout. Thus, based on grid pre-processing and improved maze algorithm, the flow chart of automatic route layout for three pipeline terminals is given. Some examples illustrate its effectiveness and practicability. References | Related Articles | Metrics

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Application of NSOH in fluorite ore flotation and its depressing mechanism Yin, Wan-Zhong (1); Lu, Zhen-Fu (1); Han, Yue-Xin (1); Li, Yan-Jun (1) 2009, 30 (2):  287-290.  DOI: - Abstract ( 562 )   HTML   PDF (313KB) ( 2037 )   A new type depressant was introduced in the flotation test of a certain fluorite ore containing carbonates and lots of sludge. Part of calcite and most of fluorite were separated from sludge by bulk flotation under conventional conditions through a rougher as first step, then the fluorite and calcite were separated by another rougher. A process of several steps in cleaning flotation was needed to obtain desirable fluorite concentrates, including the grinding once, roughing twice, clean-out five times and scavenging twice successively. The contents of CaF2 and CaCO3 in concentrate are 95.37% and 3.06%, respectively, with a recovery rate of CaF2 76.61% and the grade of CaF2 in tailing 12.36%. Theoretical study showed that Si(OH)4 and SiO2(OH)22- are the main components to depress calcite mineral in modified sodium silicate and the sequence of depressibility is SiO2(OH)22- > Si(OH)4 > HSiO3-. The depressibility was mainly due to the different adsorbabilities of Si(OH)4 and SiO2(OH)22- for different minerals among which the highly adsorbable ones are easy to be depressed, while those minerals which cannot adsorb Si(OH)4 and SiO2(OH)22- firmly even are unable to adsorb them are not easily to be depressed or cannot be depressed at all. References | Related Articles | Metrics

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Sustainability analysis of Shenyang city by checking the occupancy of ecological resources Feng, Min (1); Gu, Xiao-Wei (1); Wang, Qing (1); Jing, Ding (1) 2009, 30 (2):  291-294.  DOI: - Abstract ( 259 )   HTML   PDF (548KB) ( 573 )   Ecological footprint (EF) was used to measure the occupancy of ecological resources in Shenyang City's economic development from 1993 to 2004. The results showed that in the 12-year period the per capita resource occupancy, bearing area and deficit were 2.1075 hm2, 0.7248 hm2 and 1.3827 hm2, respectively, i.e., the per capita resource occupancy is about 3 times as large as the per capita ecological deficit. Calculated with the unit in 1000 RMB yuan, the intensity of resource use (IRU) decreased from 31.23 hm2 in 1993 to 8.39 hm2 in 2004. Equivalently, the ecological efficiency increased from RMB 3202 yuan/hm2 to 11919 yuan/hm2 in the same period, i.e., decreased 2.72 times as small as that in 1993 or an annual growth rate was 22.69%. The increasing ecological efficiency implies the gradually decreased occupancy of resource and, further, reveals that the utilization ratio of resources had been improved clearly in Shenyang City in the 12-year period. References | Related Articles | Metrics

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Portfolio model based on robust optimization and its application to investment funds in China Gao, Ying (1); Li, Chao-Jun (1); Tang, Shi-Yuan (1) 2009, 30 (2):  295-297.  DOI: - Abstract ( 249 )   HTML   PDF (270KB) ( 1257 )   According to the current situation in China and relevant constraint conditions, a robust portfolio optimization model was redeveloped to adapt to domestic circumstances. Taking account of the stock selection of China's "New Blue Chip" securities investment funds and using the linear matrix inequalities (LMI), the uncertainties of expected returns from stock prices, covariant matrix and interest rate in stock market were discussed. The weights of stocks selected and returns on investment of the "New Blue Chip" funds were therefore given and compared with the actual returns on investment funds. The empirical results indicated that the robust portfolio optimization model based on LMI is efficient and feasible in domestic funds management. References | Related Articles | Metrics

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Multi-variable induced ordered weighted averaging operator and its application Yao, Shuang (1); Guo, Ya-Jun (1); Yi, Ping-Tao (1) 2009, 30 (2):  298-301.  DOI: - Abstract ( 243 )   HTML   PDF (108KB) ( 794 )   To rise above the "ties" in induced ordering with single variable taken into account, a multi-variable induced ordered weighted averaging (MIOWA) operator is proposed to define inducing variables under special conditions so as to reflect the traits of the values of the argument from different viewpoints. During the bargaining evaluation problem (BEP) characterized with autonomy, an extended two-variable induced ordered weighted averaging operator is defined so as to enable a scheme to embody both its relative and absolute predominance in the aggregation process of multi-attribute information. A programming model is thus developed to maximize a given orness level in accordance to the non-dictatorial negotiation rules of weights to determine the position weighting vector. A numerical example is given to illustrate the feasibility of the method. References | Related Articles | Metrics

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Translation surfaces in 3-D Minkowski space Yuan, Yuan (1); Zhang, Jin-Liang (1); Li, Chun-Xiu (1); Liu, Hui-Li (1) 2009, 30 (2):  302-304.  DOI: - Abstract ( 257 )   HTML   PDF (999KB) ( 816 )   There are three kinds of vectors in the 3-D Minkowski space, i.e., space-like, time-like and light-like vectors among which choosing any two vectors as the directions of translation will divide the translation surfaces into six types. A new metric form is chosen to study the Weingarten translation surfaces which are translating in the two null directions in a pseudo-orthogonal frame. Then, the first and second fundamental forms, Gaussian curvature and mean curvature of the surfaces are directly calculated according to the principles of differential geometry. It follows that some theorems of classification of those translation surfaces are given mainly by virtue of the linear and square relationships between the Gaussian curvature and the mean curvature. References | Related Articles | Metrics