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15 December 2013, Volume 34 Issue 12 Previous Issue    Next Issue
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Information & Control

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Robust Variable Gains Tracking Controller Design for Hypersonic Vehicles〓 YE Dan， MI Yanxin 2013, 34 (12):  1673-1677.  DOI: 10.12068/j.issn.1005-3026.2013.12.001 Abstract ( 536 )   HTML   PDF (422KB) ( 581 )   A novel robust tracking control design method was proposed for hypersonic vehicles with timevarying uncertainties. Compared with traditional robust controller with fixed gains， the method presented had better capability to deal with large timevarying parameter perturbation and enhance the robustness of hypersonic vehicles. Sufficient conditions for controller design were given in the framework of robust optimization technique， and the controller gains was online adjusted based on the designed switchinglaws. The proposed robust tracking controller could not only guarantee the stability of hypersonic vehicles， but also track the command signals about height and speed quickly， even in the case of external disturbance existing. Some numerical simulations demonstrated the validity of this new robust control method. References | Related Articles | Metrics

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Motion Blur Target Tracking Method Based on Efficient SecondOrder Minimization〓 ZHAO Yue， LI Jingjiao， LI Zhenni， MA Ji 2013, 34 (12):  1678-1681.  DOI: 10.12068/j.issn.1005-3026.2013.12.002 Abstract ( 1019 )   HTML   PDF (388KB) ( 1270 )   As severe motion blur will lead to the failure of target tracking， an ESMbased template matching target tracking algorithm was proposed. First， an image structure model of motionblurred template matching was presented. Then， the ESM algorithm was introduced and motion template was tracked based on ESMMB. Subsequently， camera shutter estimated time was introduced as a parameter and selfadaptive ESMMBST tracking algorithm of motion blur caused by different shutter speed was proposed. Finally， the real video sequence tracking experiments indicated that the proposed ESMMB algorithm and the ESMMBST algorithm had a better robustness and realtime ability. References | Related Articles | Metrics

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Nonlinear Large Disturbance Rejection Controller Design for Multimachine Power Systems〓 DONG Xiujuan， JIANG Nan， JING Yuanwei， ZHANG Siying 2013, 34 (12):  1682-1686.  DOI: 10.12068/j.issn.1005-3026.2013.12.003 Abstract ( 540 )   HTML   PDF (437KB) ( 478 )   The excitation control problem in multimachine power systems was discussed. In order to avoid the conservatism which comes from estimating the upper bound of the disturbance or magnifying the equation simply， a control method of nonlinear large disturbance rejection was proposed by using backstepping method combined with minimax method. Considering that the system may get large disturbance suddenly from the generator which has occurred mechanical power disturbance， a controller of nonlinear large disturbance rejection was designed. It was indicated that the multimachine power system had good robustness and insensitivity about largedisturbance. Simulation results showed that the proposed control program can effectively improve the transient stability of multimachine power systems. References | Related Articles | Metrics

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Application of MHS Algorithm to Structural Design Problems OUYANG Haibin， GAO Liqun， KONG Xiangyong， GUO Li 2013, 34 (12):  1687-1690.  DOI: 10.12068/j.issn.1005-3026.2013.12.004 Abstract ( 508 )   HTML   PDF (348KB) ( 456 )   A modified harmony search (MHS) algorithm was proposed to solve structural design problem. A novel position updating operator was applied to enhance the development capability of solution space. Equivalent differential strategy was used to adaptively adjust harmony distance bandwidth， which could improve the searching accuracy and escape the local optima. To confirm the MHS effectiveness， three structural design optimization problems were tested. The tests demonstrated that MHS had better result than that of other four harmony search algorithms. Comparing with the best solution reported in recent literature， the MHS could find out better solutions to the optimization problem of structural design. References | Related Articles | Metrics

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Exponential Stability for Uncertain Linear DiscreteTime Systems with TimeVarying Delays ZHENG Lianwei， SONG Shuni， DAI Liangcui 2013, 34 (12):  1691-1694.  DOI: 10.12068/j.issn.1005-3026.2013.12.005 Abstract ( 575 )   HTML   PDF (311KB) ( 600 )   The uncertainties were described as timevarying parameter vectors belonging to a hyper rectangle. The problem of exponential stability for uncertain linear discretetime systems with timevarying delays was investigated by using affine parameterdependent Lyapunov functional. Exponential stability was guaranteed by the exponential decay of the Lyapunov functional. Affine parameterdependent freeweighting matrices were introduced to analyze the exponential decay of the Lyapunov functional， and the matrix inequalities containing timevarying parameters were transferred to linear matrix inequalities by using the properties of multiconvex function. Therefore， a sufficient condition for exponential stability was obtained. Since the information of upper and lower bounds of the uncertain timevarying parameters and their increments was effectively used and the convex combination method was applied when handling interval timevarying delay， the proposed method had less conservatism. An example was presented to show the effectiveness of the proposed method. References | Related Articles | Metrics

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Classification of MEG Signals Using Fisher Linear Discriminant Analysis ZHAO Haibin， YAN Shiyu， YU Qingwen， WANG Hong 2013, 34 (12):  1695-1698.  DOI: 10.12068/j.issn.1005-3026.2013.12.006 Abstract ( 461 )   HTML   PDF (430KB) ( 664 )   The magnetoenephalography(MEG)signals have higher spatiotemporal resolution than EEG signals， which can be used as input signals to build braincomputer interface(BCI)system. Feature extraction and classification methods of the MEG signals were introduced. Firstly， the MEG signals were preprocessed， and then time domain features were extracted. Finally， Fisher linear discriminant analysis(LDA)was used to classify the MEG signals. This algorithm was used to the data set Ⅲ of 2008 BCI competition which was a typical MEGbased BCI system. The offline analysis results showed that high classification accuracy of 5946% and 4324% for two subjects(subject S1 and subject S2)could be obtained using this proposed algorithm. This algorithm is more efficient and simpler than others， which can be regarded as a good reference. References | Related Articles | Metrics

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Mechanism Design of Electronic Reverse Auction Considering Supplier′s Cost Structure HUANG Min， TU Jun， LIU Yuegang， QIAN Xiaohu 2013, 34 (12):  1699-1702.  DOI: 10.12068/j.issn.1005-3026.2013.12.007 Abstract ( 677 )   HTML   PDF (423KB) ( 583 )   Procurement using electronic reverse auction is an important method for enterprises and government to reduce procurement cost. However， due to the different cost structure of different type supplier， it is difficult to carry out the mechanism of electronic reverse auction successfully. Considering two types of cost structure supplier， i. e. distributor and manufacturer， mechanism design of electronic reverse auction was studied. The basic mechanism was designed at first， which included the bidding strategy of supplier and allocation strategy of purchaser. The result revealed that the basic mechanism was efficient for the auction when the supplier was distributor. After that，taking into account the basic mechanism cannot achieve the convergence of manufacturer auction， an improved mechanism with limited strategy was proposed. The improved mechanism could achieve the convergence of manufacturer auction. Numerical simulation based on Matlab showed the efficiency of proposed mechanisms. References | Related Articles | Metrics

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An Improved ZigBee Routing Algorithm Using Neighbour Node HWANG Hakchol， DENG Qingxu， LI Chuanwen， KIM Sunhui 2013, 34 (12):  1703-1706.  DOI: 10.12068/j.issn.1005-3026.2013.12.008 Abstract ( 673 )   HTML   PDF (389KB) ( 836 )   In wireless sensor networks(WSN)， routing is a very important factor to determine the network efficiency and energy consumption， and it is also one of the key issues for the efficient use of the network and extending the life of the whole network. In order to improve network efficiency and save energy consumption of the network as a whole， a routing optimization algorithm was proposed. To reduce the number of hops from the source node to the destination node， no connection to the neighbor node data routing was used to improve network efficiency and save energy purposes. Through comparative analysis of simulation experiments， the actual effect of the improved experimental results showed that ZigBee node routing hops and delay were reduced based on the improved routing optimization algorithm， the routing efficiency was improved， and energy consumption of the network was saved as a whole. References | Related Articles | Metrics

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User Behavior Based Data Relationship Acquisition Method SUN Daming， ZHANG Bin， ZHANG Shubo， MA Anxiang 2013, 34 (12):  1707-1711.  DOI: 10.12068/j.issn.1005-3026.2013.12.009 Abstract ( 681 )   HTML   PDF (461KB) ( 888 )   Research on the relationship of data resource has become a research focus in data space area. Current data relationship researches mainly concentrate on the self attributes of data， however， the effect caused by users is neglected. As a consequence， user attention could hardly be expressed during the management， organization and application of data. User behavior based data relationship acquisition method was proposed to decide whether the user behavior is intentional by R/S analyzing of user history behavior. The user behavior sequence was excavated based on this to get user behavior pattern，and finally data relationship of data contained by the pattern in form of iTrail was built. The experiments proved that the method had a good effect. References | Related Articles | Metrics

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Design and Realization of IEEE 802154 Protocol on ATmega Platform ZHAO Hai， WANG Lei， LI Dazhou， LIN Chuan 2013, 34 (12):  1712-1715.  DOI: 10.12068/j.issn.1005-3026.2013.12.010 Abstract ( 472 )   HTML   PDF (412KB) ( 562 )   On a ATmega based selfdesigned hardware platform， the international standard protocol for IEEE 802154 was designed and implemented. In the design and implementation of the standard protocol， the idea of a finite state machine was adopted， and the standard protocol node was divided into a number of states. In addition， triggering conditions could cause transition between state and state. For IEEE 802154 protocol， the trigger condition is to receive a different frame and upper commands. Using the idea of a finite state machine complex logic processing could be separated， and the protocol could be more scalability. In order to extend the life of the nodes and improve the flexibility of the protocol， a method based on adaptive CAP and CFP regulation and management were designed and implemented. The practical application results showed that the method was effective to extend the node life and suitable for certain upper application.This method has certain significance for the IEEE 802154 protocol of applied research. The standard implementation of the field of research and development has an important role. References | Related Articles | Metrics

Materials & Metallurgy

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Effects of Annealing Temperature on Hydrogen Storage Ability of DC05EK Enamel Steel YUAN Xiaoyun， DU Linxiu， DONG Futao 2013, 34 (12):  1716-1719.  DOI: 10.12068/j.issn.1005-3026.2013.12.011 Abstract ( 625 )   HTML   PDF (1949KB) ( 556 )   The variations of the hydrogen storage ability of the enamel steel DC05EK with the annealing temperatures were studied. The effects of the precipitate behaviour on the hydrogen permeation time were studied at different annealing temperatures. The results showed that with the increase of the annealing temperature， the ability of hydrogen storage of the test steel was reduced and the hydrogen permeation time shortened due to the decrease of the amount of smallsized precipitates. When the annealing temperature increased from 730℃ to 850℃， the hydrogen permeation time reduced from 165min to 119min. When the annealing temperature was 870℃， the hydrogen permeation time rapidly reduced to 36min and the hydrogen storage ability was lack， which caused by the dissolve of smallsized precipitates. The optimal continuous annealing temperature for the enamel steel DC05EK is 730~850℃. References | Related Articles | Metrics

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Strain Hardening Behaviors of Fe11Mn4Al02C Steels CAI Zhihui， XIN Qibin， KONG Hui， DING Hua 2013, 34 (12):  1721-1724.  DOI: 10.12068/j.issn.1005-3026.2013.12.012 Abstract ( 749 )   HTML   PDF (735KB) ( 539 )   A new quenchingtempering heat treatment method was adopted for the Fe11Mn coldrolled steels which yielded a duplex microstructure consisting of ferrite and austenite when the samples were quenched in the range of 700~800℃， leading to good combinations of tensile strength(920~1150MPa)and elongation(35%~65%). The volume fraction of austenite of the coldrolled samples before and after the tensile tests was analyzed through XRD， and it was evidenced that TRIP effects occurred during the deformation. The strain hardening behavior during the tensile tests was studied. It proved that the optimized amount of ferrite and grain size of austenite made the TRIP effects occur at the appropriate time， therefore excellent mechanical properties were obtained. References | Related Articles | Metrics

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Effects of Tempering Temperatures on Microstructure and Properties of Low Carbon High Strength Bainitic Steels SUN Mingxue， WANG Meng， YI Hailong， LIU Zhenyu 2013, 34 (12):  1725-1728.  DOI: 10.12068/j.issn.1005-3026.2013.12.013 Abstract ( 819 )   HTML   PDF (849KB) ( 790 )   The variations of microstructure， mechanical properties of a low carbon highstrength bainitic steel tempered at different temperatures were investigated with optical microscopy(OM)， SEM and TEM. The results showed that the appearance of variations of the dislocation density， morphology of the precipitates， merging and coarsening of lath bainite， and decomposition of M/A islands after tempring were the main reasons for the variations of mechanical properties. Compared with the asrolled steel， after tempered at 600℃， the yield strength of the tempered steel increased 35MPa， meanwhile， the impact absorbing energy at -40℃ enhanced 49J， thus the test steel obtained the best combination of the strength and toughness. The improvement of the low temperature impact toughness after tempering mainly relied on the decomposition of the bulk M/A islands. Fine and evenly dispersed M/A islands effectively prevented the propagation of cracks， thus improved the low temperature impact toughness. References | Related Articles | Metrics

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Effects of SinglePass Hot Rolling on Oxide Scales Morphology of Fe15Si Silicon Steels LIU Xiaojiang， CAO Guangming， HE Yongquan， LIU Zhenyu 2013, 34 (12):  1730-1733.  DOI: 10.12068/j.issn.1005-3026.2013.12.014 Abstract ( 514 )   HTML   PDF (940KB) ( 677 )   Specimens of Fe15Si silicon steel were oxidized at 1000~1200℃ in air for 30min.At 1000℃ and 1100℃ fayalite was observed at the scale/substrate interface.While at 1200℃ fayalite was found both at the scale/substrate interface and at the outer oxide layer. Then after the singlepass hot rolling process， with the compression ratio of 10% and 30%， it was found that at 1000℃ and 1100℃， higher compression rate accelerated the broken of the scale layers， but the scale structure was not affected by the hot rolling process， while for the specimens oxidized at 1200℃， because of the formation of liquefied fayalite， the fayalite was squeezed into the outer oxide layer in the singlepass hot rolling. Pinning effects were weakened at the scale/substrate interface， and flatness of the interface between the scales and the substrate was improved. References | Related Articles | Metrics

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Medium Plate Quenching Latent Heat Model Based on Thermoelastic Martensitic Phase Transformation Kinetics FU Tianliang， WANG Zhaodong， LI Yong， WANG Guodong 2013, 34 (12):  1734-1738.  DOI: 10.12068/j.issn.1005-3026.2013.12.015 Abstract ( 639 )   HTML   PDF (1857KB) ( 743 )   The martensite transform amounts during the quenching process of the medium and low carbon steel plates were predicted using extend volume method. Based on modified thermoelastic altering temperature martensite transformation kinetics， blockage function was introduced to describe the phase interfacial resistance of thermal hysteresis and martensitic transformation dynamic function was established to describe the relationship to its ideal free energy and blockage functions. On this basis， blockage enthalpy which defined in blockage function was introduced to characterize the enthalpy existed on blockage interface. Through the calculation of reversible elastic energy and irreversible work， the latent heat of the phase transformation was finally obtained according to the change of the Gibbs function and the model of the latent heat of phase transformation was established. The simulated results according to the model were in good agreement with the experimental results， which indicated that this model was suitable to use to simulate martensitic transformation during quenching process of medium and low carbon steel plates of moderate thickness. References | Related Articles | Metrics

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Effects of Process Parameters on Primary Al3Zr Phase in AlZr Master Alloys LI Fei， ZHU Qingfeng， LI Lei， CUI Jianzhong 2013, 34 (12):  1739-1743.  DOI: 10.12068/j.issn.1005-3026.2013.12.016 Abstract ( 573 )   HTML   PDF (1002KB) ( 802 )   The effects of processing parameters on the morphology， size， amount and distribution of the primary Al3Zr phase during the solidification of AlZr master alloys were investigated by the aluminothermic reduction method in the AlK2ZrF6 reaction system. The results showed that the morphologies of the primary Al3Zr crystals transformed from the small blocky shape to long strip shape， and the size of the primary Al3Zr increased while their amount decreased， with the increase of the molten reaction temperature. When the reaction temperature was below 1000℃， Al3Zr crystals exhibited small blocky shapes; when the temperature was higher than 1000℃， they displayed long strip shapes; when temperature was 1000℃， they displayed the small blocky and long strip mixed morphologies. The sizes of the Al3Zr became larger and the amounts of them became fewer in the refractory mold in comparison to that in the iron mold. With the increase of the K2ZrF6 content， the volume fraction of Al3Zr phase increased gradually， and these crystals grew much finer and with more uniform distribution in the Al matrix. References | Related Articles | Metrics

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Activity Calculation for the Components in CaOAl2O3 and CaOSiO2Al2O3 Slags〓 LYU Ningning， YU Jingkun， SU Chang， WANG Hongzhang 2013, 34 (12):  1743-1746.  DOI: 10.12068/j.issn.1005-3026.2013.12.017 Abstract ( 648 )   HTML   PDF (387KB) ( 759 )   Calculation model for activities of the components in CaOAl2O3 and CaOSiO2Al2O3 slags was established according to the molecule and ion coexistence theory. The activities of the components in CaOAl2O3 and CaOSiO2Al2O3 slags were calculated， and the influence of w(CaO) on the activities of the components was discussed. The results show that when the w(CaO)in CaOAl2O3 slag is less than 45%， with increasing the w(CaO)， the activities of 3CaO·Al2O3 and 12CaO·7Al2O3 in slag increase， however， the activity of CaO·Al2O3 changes little. When the w(CaO)in CaOAl2O3 slag is more than 45%， with increasing the w(CaO)， the activities of CaO·Al2O3 and 12CaO·7Al2O3 in slag decrease， however， the activity of 3CaO·Al2O3 increases slightly. In the CaOSiO2Al2O3 slag， the activity of 12CaO·7Al2O3 is lower than that in the CaOAl2O3 slag， with increasing the w(CaO)， the activities of CaO and 3CaO·Al2O3 increase， and the activity of 2CaO·SiO2 decreases， however， the activity of CaO·Al2O3 increases at first and then decreases. References | Related Articles | Metrics

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Surface Emissivity Measurement Technique Based on Infrared Thermal Imager〓 BAI Jingchen， YU Qingbo， HU Xianzhong， WANG Hao 2013, 34 (12):  1747-1750.  DOI: 10.12068/j.issn.1005-3026.2013.12.018 Abstract ( 1093 )   HTML   PDF (444KB) ( 2151 )   The tworeferencebody method can not measure accurately the emissivity of an object.According to the spectral response of an infrared thermal imager， a new precise measurement method with an infrared thermal imager was developed to measure the emissivity of an object. The determination of the parameter n in the tworeferencebody method is improved， and a new formula for emissivity calculation is obtained. Based on the analysis of the applicable conditions of the new measurement method， a measuring method to obtain accurate object emissivity is presented. Applications show that the measurement results are satisfactory. References | Related Articles | Metrics

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Effect of Additives on YBa2Cu3O7-δ Superconductive Coatings Prepared by Electrophoretic Deposition〓 LUO Qingwei， LI Yingnan， LI Fenghua， FAN Zhanguo 2013, 34 (12):  1751-1754.  DOI: 10.12068/j.issn.1005-3026.2013.12.019 Abstract ( 645 )   HTML   PDF (1358KB) ( 488 )   Due to its high infield superconducting performance， high irreversible magnetic field， low AC loss and high transition temperature， YBa2Cu3O7-δ(YBCO) has been a hot research object. Suitable preparation technologies for industrial scale manufacturing of YBCO superconducting films have always been a hot issue in the last several decades. YBCO superconductive coatings were prepared on Hastelloy alloy with lowcost electrophoretic deposition technology. Additives have great influence on the stability of electrophoretic solution and coating property. The relationship between additives(types and contents of additives) and YBCO coating was studied. The results show that the samples prepared by adding 005g PVB have good superconductivity， and the critical current density can reach up to 100 A/cm2(0 T，77 K). References | Related Articles | Metrics

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Water Model Study of Bubble Behavior in Matte Smelting Process with Oxygen Bottom Blowing〓 WANG Dongxing， ZHANG Tingan， LIU Yan， ZHU Xiaofeng 2013, 34 (12):  1755-1758.  DOI: 10.12068/j.issn.1005-3026.2013.12.020 Abstract ( 750 )   HTML   PDF (502KB) ( 586 )   Water model study of oxygen bottom blowing converter for matte smelting was carried out， and the effects of main factors such as nozzle numbers， angles， diameters and the gas velocity on the mean bubble diameter， gas holdup and liquid splashing were investigated. The results show that largediameter nozzle increases the mean bubble diameter， and leads to splashing with serious slag entrapment. The increase of inclination angle of nozzles weakens the splashing in the bath and decreases the gas holdup. Larger gas velocity has advantage for bubbles dispersion and disintegration， but the splashing gets more serious. Compared with single nozzle， the performance of double nozzle is better， and its splashing is weaker. When the angle between two nozzles is 44°， the gas holdup reaches its maximum of 9%. References | Related Articles | Metrics

Mechanical Engineering

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Influence of Tool Diameter and Abrasive Particle Size on Surface Roughness in Micro MillGrinding〓 WANG Chao， GONG Yadong， YIN Guoqiang， CHENG Jun 2013, 34 (12):  1759-1762.  DOI: 10.12068/j.issn.1005-3026.2013.12.021 Abstract ( 781 )   HTML   PDF (973KB) ( 697 )   Micro millgrinding is a novel machining technology with characters of micro milling and micro grinding. To provide theoretical support and data reference for parameters optimization of the micro millgrinding tools， different materials were machined with the cubic boron nitride micro millgrinding tools. The influence of the tool diameter and abrasive particle size on workpiece surface quality were analyzed and compared with those of micro milling. The results show that if appropriate tool parameters are used in micro millgrinding，submicron surface roughness will be obtained and it is better than that machined by micro milling. Smaller particle size or larger tool diameter will make surface quality better to some extend in micro millgrinding，and the influence of particle size on surface roughness is more significant. References | Related Articles | Metrics

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Tooth Profile Modification Mechanism and Its Influence on Temperature Fields〓 XUE Jianhua， LI Wei 2013, 34 (12):  1763-1767.  DOI: 10.12068/j.issn.1005-3026.2013.12.022 Abstract ( 677 )   HTML   PDF (1013KB) ( 658 )   The tooth stiffness was calculated by the analytical method and the finite element method. The tooth profile modification mechanism and the influence of machining errors on loadsharing ratio， transmission errors and temperature fields were analyzed by stiffness method. The results show that the long modification is superior to the short modification in reducing meshing shock. The transmission errors fluctuation is the smallest and transmission is the smoothest when long modification index equals 122. The profile modification can alter the distribution of the bulk and flash temperature， and translate the high temperature zone from tooth root and addendum to the tooth profile central. Thus the highest temperature of the tooth root and addendum reduces and the scuffing load capacity is improved. The machining error can weaken the profile modification effect and cause dynamic load and instantaneous high temperature. The machining errors， runningwear， and thermal elastic deformation should be considered when setting the amount of profile modification. References | Related Articles | Metrics

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Optimization Research on the Tool Structure Parameters and Material of the Glass Fiber Short Cutting〓 ZHOU Jilie， FENG Chufan 2013, 34 (12):  1768-1772.  DOI: 10.12068/j.issn.1005-3026.2013.12.023 Abstract ( 667 )   HTML   PDF (1192KB) ( 633 )   The production of short glass fiber had low efficiency and high cost because of the lack of study on special tool. To change this situation， the special tool was researched. Firstly， a bendcutting model of the glass fiber was established. Then， the cutting depth and angle were discussed theoretically. The edge angle of the tool was lucubrated to get the edge selection range and the range was further verified by the years of production test. It showed that the further optimization of the edge angle was relevant with the tool material and the ideal properties of the tool material were analyzed. SKS was selected for a shortcutting test to compare with the T12A tool. It is found that the service life of CrWMn tool is 5 times longer than general carbon steel tool. The productivity of the short glass fiber is greatly improved. References | Related Articles | Metrics

Resources & Civil Engineering

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Study on Process Mineralogy of a High Phosphorus Oolitic Hematite Ore〓 SUN Yongsheng， HAN Yuexin， GAO Peng， ZHOU Mangeng 2013, 34 (12):  1773-1777.  DOI: 10.12068/j.issn.1005-3026.2013.12.024 Abstract ( 886 )   HTML   PDF (1654KB) ( 1029 )   The chemical composition， mineral composition， dissemination characteristics and ooidal characterization of the oolitic hematite ore were detailedly investigated through optical microscope， electron probe， XRD， MLA automatic detection and chemical analysis. The results showed that iron mainly occurs in the form of hematite and limonite，and the primary gangue minerals are quartz， chamosite and collophanite. Mineral composition of the ore is complex， and hematite is usually wrapped with annular and layer upon layer by quartz， chamosite， collophanite and clay minerals to form ooids. Ooids in the ore can be divided into ironrich ooid and ironpoor ooid， which are mostly distributed in the size range of 01～05mm. The results may provide the basis for the rational exploitation for the iron ore resource. References | Related Articles | Metrics

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Effects of Roasting Modification on the Characteristics and AmmoniumNitrogen Removal Ability of Zeolite〓 HUO Hanxin， LIN Hai， DONG Yingbo， LIU Quanli 2013, 34 (12):  1778-1782.  DOI: 10.12068/j.issn.1005-3026.2013.12.025 Abstract ( 640 )   HTML   PDF (731KB) ( 1118 )   The natural clinoptilolite as the object of study， which were modified by roasting at different temperature and time gradient， the changes of structural characteristics and ammonianitrogen removal ability in recycled water for zeolite after roasting modification were studied emphatically. The results showed that specific surface of zeolite increased， crystal structure， pore size distribution and cation exchange capacity of zeolite changed slightly， but ammoniumnitrogen removal rates increased from 5315% to 7213%， because of the remove of water and impurity in the pore channel for natural clinoptilolite in the suitable roasted temperature and time. While the zeolite roasted in overtemperature and excessive time， characteristic diffraction peak of natural zeolite became weaker， the framework collapsed， specific surface area and cation exchange capacity decreased dramatically， pore size distribution changed significantly， and ammoniumnitrogen removal ability decreased significantly. References | Related Articles | Metrics

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Preparation and Formation Mechanism of Flowerlike Magnesium Carbonate Pentahydrated〓 WANG Yulian， YIN Wanzhong， ZHONG Wenxing， HOU Ying 2013, 34 (12):  1783-1786.  DOI: 10.12068/j.issn.1005-3026.2013.12.026 Abstract ( 611 )   HTML   PDF (785KB) ( 784 )   Flowerlike magnesium carbonate pentahydrated was prepared by aquasolution method using magnesite as raw materials and potassium dihydrogen phosphate as additives. Microtopography and phase composition of the crystal were analyzed by scanning electron microscope(SEM)， Xray diffraction(XRD) and FTIR. The influence of thermal decomposition time on the crystal morphology was explored. The formation mechanism of products was studied， as well as crystal structure of magnesium carbonate pentahydrated. The results showed that flowerlike magnesium carbonate pentahydrated with 15~30 micrometers long and 100~500 nanometers wide， can be successfully synthesized under 30min of thermal decomposition time. For the magnesium carbonate pentahydrated crystal， Mg2+ presents two different octahedralcoordination， which constitutes Mg(H2O)2+6 and［Mg(H2O)4(CO2-3)2］2-， and its chemical formula is Mg(H2O)6·Mg(H2O)4(CO2-3)2. The adsorption of potassium dihydrogen phosphate on the surface of magnesium carbonate pentahydrated changes the surface energy and growth rate of individual crystal faces， promotes it to nucleate and gradually superimpose flowerlike bodies. References | Related Articles | Metrics

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A New DrukerPrager Type Criterion and Its Implementation〓 ZENG Xinfa， PENG Zhenbin， HE Jie， PENG Kai 2013, 34 (12):  1787-1790.  DOI: 10.12068/j.issn.1005-3026.2013.12.027 Abstract ( 685 )   HTML   PDF (647KB) ( 730 )   Based on MohrCoulomb(MC)criterion and plane strain condition， a new DruckerPrager(DP) type criterion under nonassociated flow rule is presented. In the new DP criterion the volumetric plastic strain is introduced and its increment equals to that of the MC criterion. Based on the analysis on π plane， it is found that the proposed DP type criterion is better than the DP criterion compared to the MC circumscribed circle or MC inscribed circle when it is applicable to the conditions for stress Lode angle less than zero. Both theoretical and numerical analysis show that this criterion exactly matches with MohrCoulomb criterion in the predicted slope safety factor， agreeing well with that by Spencer method， and it is more accurate than those from classic DP criteria. Both ultimate load and the slip line field obtained from the proposed criterion in analysis of foundation are in agreement with theoretical solution of Prandtl. References | Related Articles | Metrics

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Prediction of Chlorophylla Concentration in Dahuofang Reservoir Based on BP Neural Network 〓 WANG Qi， MENG Wei， MA Yunfeng， HU Xiaomin 2013, 34 (12):  1792-1795.  DOI: 10.12068/j.issn.1005-3026.2013.12.028 Abstract ( 545 )   HTML   PDF (562KB) ( 596 )   With the CCD data of HJ1 satellite and the calculation of MATLAB， this paper analyzes the relationship between chlorophylla concentration and 65 band combinations which consist of four bands(nearinfrared band， red band， green band and blue band) of multispectral CCD data. The study finds that band combination of T1=B4/B3 has the highest correlation with the chlorophylla concentration. Then onedimensional linear model was established by taking T1 as the argument. The degree of fitting R2， the root mean square error and the relative error of the verification points were compared based on the BP neural network. It shows that it is feasible to predict the chlorophylla concentration of Dahuofang reservoir with BP neural network， and the method is better than linear model. References | Related Articles | Metrics

Management Science

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Why Delighted Customers Are Not Loyal? Moderating Role of Involvement Context and Switching Costs〓 ZHANG Yuexian， MA Qinhai， ZHANG Xiaofei 2013, 34 (12):  1796-1799.  DOI: 10.12068/j.issn.1005-3026.2013.12.029 Abstract ( 433 )   HTML   PDF (512KB) ( 526 )   It has gained consistent finding that the real way of increasing customer loyalty is not only to increase customer satisfaction but also to enhance delight. This paper explored the moderating role of involvement context and switching cost on the relationship between customer delight and loyalty depending on a survey of department store and hairdressing service. The research based on the regression analysis method finds that the involvement context and switching costs significantly moderated the relationship between customer delight and loyalty. Additionally， involvement context had significant interactions with switching costs on the relationship between delight and loyalty. This research clearly explains the path between customer delight and loyalty， which can provide a new way of strengthening customer loyalty. References | Related Articles | Metrics

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Empirical Study on Effect of Organizational Learning on Strategic Change of MNC〓 NING Ye， LIU Lu 2013, 34 (12):  1801-1804.  DOI: 10.12068/j.issn.1005-3026.2013.12.030 Abstract ( 475 )   HTML   PDF (351KB) ( 532 )   The organizational learning is thought to be the most important factor to affect strategic change of MNCs(multinational corporations). Based on related literatures， a research model of the relationship between organizational learning and strategic change is constructed， in which organizational learning is measured by explorative learning and exploitative learning， and strategic change is measured by positioning difference and concept difference. Then hypothesis are provided and tested with empirical methods. The results show that organizational learning affects strategic change significantly. The research can be used to explain the effect of organizational learning on strategic change in MNCs theoretically and practically. References | Related Articles | Metrics