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• 2012 Volume 33 Issue 2
  Published: 10 March 2012

    

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  Experiment of specific energy consumption for straw bale recompressing

  HUANG Wencheng, WANG Guanghui, WANG Decheng

  2012, 33(2): 125-129. https://doi.org/10.3969/j.issn.1671-7775.2012.02.001

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  The specific energy consumption of recompression for fibrous agricultural materials was determined by material characteristics and compression conditions. In order to investigate the effects of different factors on the specific energy of recompression, compression tests and analysis were conducted with different compression directions, initial densities and moisture contents. The results show that compression direction has slight effect on the specific energy. The minimum specific energy consumption can be obtained with an optimum initial density value for the same compressed volume. When compressed density is lower than 500 kg·m-3, the specific energy consumption has a positive relationship with compressed density. The specific energy is decreased with the increasing of moisture content in safe storage range.
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  Influence of pulse ultrasonic on water soluble protein conformation of Tenebrio molitor(L.) larva

  DAI Chunhua, TANG Jian, GU Xiaohong, MA Haile

  2012, 33(2): 130-133. https://doi.org/10.3969/j.issn.1671-7775.2012.02.002

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  The effects of pulse ultrasonic treatment with power of 1 000 W on water soluble protein conformation of Tenebrio molitor (L.) larva were investigated. The results show that the ultraviolet absorption of protein is increased within 25 min ultrasonic treatment. The surface hydrophobicity has remarkable change with maximum value at 10 min，and decreases gradually from 10 to 25 min. The free sulfhydryl (SH) content decreases slightly after pulse ultrasonic treatment for 5 min，and then increases gently. Protein particle size decreases with treatment time from 0 to 15 min, and increases significantly after 20 min treatment. The CD analysis indicates that α-helix content is decreased, while β-structure and random coil content are increased by pulse ultrasonic treatment. SDSPAGE demonstrates that the primary structure of water soluble protein is not changed by pulse ultrasonic treatment.
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  On-line monitoring method of ball mill pulverizing capacity integrated mill shell vibration

  WANG Heng, JIA Minping, HUANG Peng, CHEN Zuoliang

  2012, 33(2): 134-138. https://doi.org/10.3969/j.issn.1671-7775.2012.02.003

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  To solve the disadvantage of on-line monitoring method for ball mill pulverizing capacity, a hybrid soft sensor model was proposed based on mechanism knowledge and black-box model. The key factors of pulverizing capacity were analyzed to compare vibration signals of mill shell with those of conventional mill bearing.The comparison reveals that the vibration signals of mill shell presents  high change sensitivity on fill level. Pulverizing capacity equation and theoretic value were obtained based on mechanism models and corrected by LS-SVM model to improve accuracy of mechanism models. The modeling results show that the proposed hybrid model can effectively represent the change tendency and dynamic performances of  pulverizing capacity with higher accuracy than that of single mechanism models.
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  Prediction of interior lowfrequency structure noise characteristics of aluminum alloy metro vehicle

  ZUO Yanyan, GENG Feng, LI Shudong

  2012, 33(2): 139-143. https://doi.org/10.3969/j.issn.1671-7775.2012.02.004

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  To analysis the interior low-frequency structural noise caused by car body panels vibration from track irregularities, the finite element model of aluminum alloy metro vehicle car body and the sound field boundary element model of car interior space were established. The dynamic analysis was performed based on the proposed models of vehicletrack coupled dynamic system.According to the dynamic loads on involved positions of body structure and the finite element harmonic response analysis method in ANSYS software, the vehicle structure body vibration responses under random irregular rail-track actuations were achieved. The vehicle body structure vibration responses were transfered as boundary conditions to the boundary element model of car interior sound field in SYSNOISE software. The interior sound field characteristics were predicted in the range of 0-200 Hz at different inside place of car. The results indicate that the maximum inner sound pressure level is more than 75 dB.The  interior lowfrequency structural noise characteristics in car body of aluminum alloy metro is influenced directly by car body structure characteristics and actuating loads.The interior structural noise can be reduced by decreasing rail-track actuations or optimizing vehicle body structure.
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  Shadow elimination method integrated edge features and local texture characteristic

  CAI Yingfeng, ZHANG Weigong, WANG Hai

  2012, 33(2): 144-149. https://doi.org/10.3969/j.issn.1671-7775.2012.02.005

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  To achieve shadow elimination in video target segmentation, according to confidence, characters of foreground edge projection and local texture features were merged to propose a novel shadow extraction strategy. By adaptive Gaussian method， the foreground containing shadow was obtained to extract dynamic background. The edge difference between foreground and background in minimum enclosing rectangle area of foreground was calculated to achieve edges and shadow of vehicle. Otsu algorithm was used for video segmentation. The area with high confidence was labeled as shadow, and that with low confidence was labeled as vehicle. According to the jumping level of local texture between current frame and background frame, the remaining shadow concerning with vehicle was found out in the area with middle confidence by further processing. Experimental results demonstrate that the proposed method can effectively remove huge shadows which may lead to heavy deformation with over 90％ elimination rate. The algorithm can be applied in object detecting and tacking in intelligent video surveillance system with good real-time performance.
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  Simulation of fuel injection and combustion process in diesel engine fueled with Jatropha curcas oil

  WANG Ziyu, LUO Fuqiang, LIANG Yu, GUO Jian

  2012, 33(2): 150-154. https://doi.org/10.3969/j.issn.1671-7775.2012.02.006

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   Based on three dimension CFD software, a simulation model was established for the work processes of diesel engine fueled with diesel or Jatropha curcas oil. The combustion process and spray development process of different fuels were simulated. The verifying of proposed model on single-cylinder direct injection diesel engine illuminates that simulation results are well consistent with test results. The spray development process and the fuel mass fraction distribution of 2 fuels were compared to discuss the spray difference. The results show that the distribution variation tendency of fuel mass fraction for different fuels is similar. The spray speed of Jatropha curcas oil is slightly larger at early injection stage and slower at main injection stage than those of diesel with low spray penetration.The injection timing of Jatropha curcas oil is early with smaller fuel mass fraction variation velocity than that of diesel. The zone of high fuel mass fraction of Jatropha curcas oil at later combustion stage is larger than that of diesel.
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  Analysis of PAHs formation with oxygenated fuels based on ROP

  WANG Zhong, LI Mingdi, LI Lilin, CHEN Lin, XU Guangju

  2012, 33(2): 155-159. https://doi.org/10.3969/j.issn.1671-7775.2012.02.007

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  According to shock tube model, the formation of benzene, naphthalene, phenanthrene and pyrene was analyzed by simulating their production rate through ROP to investigate the PAHs formation paths of oxygenated fuels. The results show that the magnitude of production rate of ethanol, DME and DMC is orderly decreased with initial equivalent ratio of 1.0 and temperature of 1 600 K. The polymerization of propargyl is the main path for benzene formation. Naphthalene is formed mainly through second HACA reaction and combination reaction of phenyl and vinyl acetylene. Phenanthrene and pyrene are mainly formed through HACA reaction. H and OH radicals play an important role in the oxidation of PAHs. In the reaction of third body ″M″, ethanol can inhibit PAHs formation. DME has slight effect on PAHs formation, while DMC can promote PAHs formation.
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  Experiment of frequency range of wall attaching fluidic oscillator

  XIANG Qingjiang, YUN Qianglong, LI Hong, WU Yanlan

  2012, 33(2): 160-164. https://doi.org/10.3969/j.issn.1671-7775.2012.02.008

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  The structure and the working principle of three types of fluidic oscillator were compared.The oscillating frequency of wall attaching fluidic oscillator is adjustable, which is different from fluidic flowmeter and self-excited oscillator. In order to apply the fluidic oscillator in liquid jet gas pump to achieve a new kind of jet, the oscillating frequency range produced by wall attaching fluidic oscillator was analyzed. The frequencies were obtained from experimental data of wall pressure fluctuation. For a given structure and specific working pressure of fluidic oscillator, the experimental results show that there is a suitable range for signal water flow rate and signal pipe length to keep fluidic oscillator working normally. Beyond this range, the jets of wall attaching fluidic oscillator will disperse. As the working pressure changes between 200 kPa and 450 kPa, the signal pipe length varies from 300 mm to 1 000 mm with signal water flow rate range from 160 g·min-1 to 425 g·min-1 and wall attaching fluidic oscillator frequency range from 0.8 Hz to 2.7 Hz. Increasing the frequency range can decrease the oscillator structure size.
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  Numerical calculation and experiment  of hydraulic turbine

  YANG Sunsheng, KONG Fanyu, SHAO Fei, XUE Ling

  2012, 33(2): 165-169. https://doi.org/10.3969/j.issn.1671-7775.2012.02.009

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    A test rig for single stage hydraulic turbine was designed to obtain extra performance curves through experiment. Numerical simulation of the designed hydraulic turbine was performed by all domains and structural mesh technique. The pressure field and velocity field at different flow rate were discussed to acquire flow field distribution within hydraulic turbine. The variation of velocity field within turbine impeller and outlet pipe at different flow rate was analyzed according to velocity triangle. The results show that a centrifugal pump can run reversely as high efficiency turbine without any modification. The relative error at the best efficiency between numerical calculation and experimental results is 4.85%. The absolute pressure within hydraulic turbine decreases gradually along the volute, impeller and outlet pipe,while the pressure difference between inlet and outlet increases with the increase of flow rate. Vortex regions are located at impeller blade suction and pressure side with location and region size varied by flow rate. The absolute tangential velocity at outlet pipe section is varied with flow.
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  Numerical simulation of 3D lib-driven cavity flow based on AMG method and multiblock non-orthogonal grid

  JIANG Guangbiao, HE Yongsen, SHU Shi

  2012, 33(2): 170-175. https://doi.org/10.3969/j.issn.1671-7775.2012.02.010

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  To apply AMG method in fast solving FVMbased discrete systems of NavierStokes equations, the non-orthogonal hexahedron collocated grid system was set up to numerically simulate lib-driven flow in vertical and 45° inclined wall cavity. Based on the SIMPLE algorithm of non-orthogonal hexahedron collocated grid, the structure and the compressed sparse row(CSR) storage scheme of coefficient matrix were obtained by N-S equation and multi-block grid. Numerical simulation programs were designed to solve the flow parameters of governing equations by AMG method. Compared computing results with existing results, the flow structure figures of 3D lib-driven cavity flow were obtained, and the algorithm was verified. The results show that AMG and the related algorithms can be applied in the numerical simulations of fluid flow in complex field, and are suitable for large scale numerical simulation of fluid flow.
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  Numerical calculation and experimental verification of stainless steel stamping submersible well pump

  WANG Chuan, LU Weigang, SHI Weidong, ZHOU Ling, LI Hui

  2012, 33(2): 176-180. https://doi.org/10.3969/j.issn.1671-7775.2012.02.011

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  In order to improve numerical calculation accuracy and verify Fluent software feasibility of stamping well pump. The 4SP8 stamping submersible well pump was numerically simulated based on Fluent software and technological features of stamping pump. Numerical calculation of different stages of stamping well pump model was carried out for different grid number, convergence precision, roughness, turbulence models and algorithms. The most suitable set method of numerical simulation for stainless steel stamping submersible well pump was achieved to compare prediction performance with experimental results. The results show that standard k-ε turbulence model and SIMPLEC algorithm are most appropriate to make numerical calculation for the whole flow field of two-stage stainless steel well pump at the conditions with grid size of 1.4 mm, convergence precision of 10-5 and roughness of 0 mm. The difference between simulation data and experimental data is small with almost the same trend. The study is instructive to the numerical simulation of stainless steel stamping submersible well pump.
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  Multi-beam antenna calibration system of satellite by triple -toned calibration method

  ZHAO Xingwei, GONG Wenbin, LIANG Xuwen

  2012, 33(2): 181-186. https://doi.org/10.3969/j.issn.1671-7775.2012.02.012

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   To solve the asynchronous considering for low and high frequency of common calibration, the triple-toned calibration method was proposed based on the characteristics of multi-beam antenna system of satellites. The channels of multi-beam system was measured by three single tone calibration signals to ca-librate the full band amplitude-phase errors with quadratic fitting. The measurement errors were decreased effectively by fitting dots from repetitive measurements. The channel amplitude-phase response was compensated by the inverse function of the fitting characteristic curve. The single channel calibration was realized when the full band characteristic curve was turned to horizontal line. The interchannel errors were calibrated and compensated by amplitude-phase compensating term. The triple-toned method was applied in two calibration schemes of satellite antenna, near-field and far-field calibration. The results show that the proposed method can effectively solve the problem of channel mismatch.
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  Design and analysis of low energy protocol for linear wireless sensor network

  DUAN Shihong, WANG Qin, WAN Yadong, YU Yanwei

  2012, 33(2): 187-192. https://doi.org/10.3969/j.issn.1671-7775.2012.02.013

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  In order to effectively monitor pipeline cathode protection equipment, a remote auxiliary monitoring system based on linear wireless sensor network was built up, and a set of protocols with low power and high reliability was also proposed. The protocol set included clustered fusion and chain-style multi-hop protocol (CMCH) for uploading data and stepped radio awaken flooding protocol (SRWF) for issuing downstream data or alarm. Based on energy consumption model of linear wireless sensor networks,mechanisms of power control and data fusion were applied in CMCH protocol to support power conservation with reliable transmission. Flooding agreement with time stamp was optimized by SRWF protocol to issue commands from remote centre or alarm from fault nodes on time. CMCH protocol was simulated on OMNet++ platform, and the monitoring system has been deployed in long -buried oil pipeline for 2 months. The results show that it is important to choose key protocol parameter for low power requirement from simul
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  Finite element analysis of transient air gap magnetic field for deep bar squirrel cage asynchronous magnetic coupling

  YANG Chaojun, LU Yugen, LI Zhibao, HU You, GUAN Chunsong

  2012, 33(2): 193-198. https://doi.org/10.3969/j.issn.1671-7775.2012.02.014

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  To investigate output torque of deep bar squirrel cage rotor asynchronous magnetic coupling in working, the transient air gap magnetic field was simulated. Based on the transient theoretical analysis of asynchronous magnetic coupling, the effects of magnetic pole numbers, permanent magnet thicknesses, air gap lengths, slot numbers of inner rotor and width-length ratios of slot （the ratio of the slot width and the slot depth）on the transient air gap magnetic field were analyzed by 2D and 3D simulation in Ansoft Maxwell. The experiments were conducted to verify the 3D simulation analysis. The results show that the optimal value of output torque can be oabtained in a certain outside diameter with magnetic poles of 14, permanent magnet thickness of 8 mm, slot number of 24 and slot widthlength ratio of 0.42. The output torque is markedly affected by slot depth with maximum torque for slot depth of 18 mm. The conclusions have guiding significance for further optimizing of deep bar squirrel cage rotor asynchronous magnetic coupling.
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  Video keyframe extraction using ordered samples clustering based on artificial immune

  ZHAN Yong zhao, WANG Man rong, KE Jia

  2012, 33(2): 199-204. https://doi.org/10.3969/j.issn.1671-7775.2012.02.015

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   In view of sensitivity of initial samples division and easy fall into local optimum in existing unsupervised clustering methods of video key-frame extraction without considering temporal order of shot content, a novel ordered samples clustering algorithm was proposed based on artificial immune. According to traditional artificial immune based clustering algorithm, memory recognition mechanism for antigens was introduced, and clone and hyper mutation mechanism for antibodies was improved. A video key -frame extraction method of artificial immune based on ordered samples clustering was proposed. The image frame sequence in a shot was regarded as an antigen sequence invading the body. Based on the mechanisms of primary response and second response, the memory cell pools for each antigen were obtained. The continuous antigens recognized by the same memory cell pool was formed a cluster, and the frame nearest to the cluster center was extracted as a key-frame. The experiments on various videos were completed. The results show that the proposed method has high fidelity and compression ratio, and the key-frames reflecting real shots contents can be extracted effectively.
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  Control system of special laser micro-manufacturing technology  

  FU Yonghong, PAN Guoping, HUA Xijun, FU Hao, GAO Xingdong

  2012, 33(2): 205-208. https://doi.org/10.3969/j.issn.1671-7775.2012.02.016

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   Based on the acoustic-optic Q-switched Nd technology of YAG laser, control system of special laser micro-manufacturing technology was designed to process the inner surface of engine cylinder. According to the programing of MC8041A motion control card and self-developed laser Q-switch card, the mechanical motion system of equipment and the output of laser Q-signal were controlled. Four-axis servo motors were controlled by the motion control card. The feedback pulses from a high accuracy incremental rotary encoder on rotational axis were received by laser Q-switch card to output laser Q-signal after counting and frequency dividing. With the laser Q-switch card′s coordinated control between rotational motion of laser head and output of single laser pulse, the laser micro-manufacturing approach of single pulse one time with repeating at intervals was achieved. By the proposed approach, laser micromanufacturing can be performed on the inner surface of engine cylinder with high efficiency and quality.
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  Transient reflectivity of Cu films and influence of annealing

  REN Naifei, WANG Rongxiao, GU Jiafang, CHEN Qiuyue

  2012, 33(2): 209-213. https://doi.org/10.3969/j.issn.1671-7775.2012.02.017

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  In order to study ultrafast thermalization dynamics of short-pulsed laser irradiated metal, Cu films were deposited on glass substrates by magnetron sputtering, and some samples were annealed at different temperatures. The transient reflectivity of films was detected by femtosecond laser pump-probe, and the influence of annealing on transient reflectivity was also discussed. The results show that the transient reflectivity curve of Cu films can be divided into four stages of stable state, rapid increase, attenuation and recover. The peak value and the delay time of attenuation stage of transient reflectivity curve are sensitive to annealing. With increased annealing temperature,  the attenuation stage time is increased with decreased peak value, which means the cooling rate is slow. The predicted electron temperature based on twotemperature model is consistent with experimental data, but the predicted electron cooling time is longer than that of experiment.
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  Calculation and comparison between alternate and continuous controlled cooling technology for X65 pipeline steel plate

  ZHANG Defeng, LU Jiansheng, LV Jianguo , SONG Peng, DU Zhonglin

  2012, 33(2): 214-218. https://doi.org/10.3969/j.issn.1671-7775.2012.02.018

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  To decrease the residual stress and warping of X65 pipeline steel plate after controlled cooling, a thermo-mechanical coupled FEM model was established according to linear mixture thermal expansion model,  modified Avrami transformation dynamics model and Leblond transformation induced plasticity (TRIP) model. All relevant physical effects of elastoplastic deformation, thermal expansion, latent heat, transformation dilatation and TRIP effect were considered in the FEM model. Temperature, residual stress, residual strain and warping of X65 pipeline steel plate were analyzed by the proposed model under two controlled cooling technologies. The results show that the temperature of plate under alternate controlled cooling is 7 ℃ less than that under continuous controlled cooling. The residual tensile stress peak value near top surface is decreased by 44 MPa with enhanced residual compressive strain peak value of 0.001 near bottom surface, while the warping is reduced from 0.54×10-3 to 0.09×10-3. Alternate controlled cooling can reduce residual stress and warping of plate.
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  Design and experiment of split-flow device for roof initial rainwater

  HUANG Yongqiang, XU Mingli, WU Chundu, WU Tao

  2012, 33(2): 219-222. https://doi.org/10.3969/j.issn.1671-7775.2012.02.019

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   To make storm runoff and initial rainwater with poor quality meet the requirement of reuse,  a combined split-flow device of roof initial rainwater was designed based on water quality control technology. The split-flow cell volume was regulated according to rainwater pollutants scouring law and rainfall intensity. The intercepted rainwater was penetrated directly into ground through the bottom permeable components. The split-flow device was mainly composed of regenerated resin, while the bottom permeable components were made up of aggregate and binder synthetic material. The test results show that with initial rainwater runoff discarding of 3 mm, 50%-70% pollutants of SS, turbidity and COD can be intercepted with the highest removal efficiencies of 74.95%，50.00%，60.90%, respectively. The designed device just need regular maintenance without any personnel management after rain. 
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  Gray relation analysis of atrazine adsorption onto surficial sediments and natural surficial coating samples

  LI Yu, WANG Qian, GAO Qian, WANG Ao

  2012, 33(2): 223-227. https://doi.org/10.3969/j.issn.1671-7775.2012.02.020

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  The main sites of atrazine (AT) adsorption onto the surficial sediments and natural surficial coating samples in Cd2+/AT, Cu2+/AT composite contamination systems were filtrated according to gray correlation of the active fractions of Fe oxides, Mn oxides, organic materials and their interactions. A multiple regression model between AT adsorption amount and main adsorption sites was established. The results show that Cd2+ expresses synergetic effect on AT adsorption with the most significant efficiency at Cd2+ level of 0.2 mg·L-1. The antagonistic effect caused by Cu2+ on AT adsorption is generally enhanced by the increasing of Cu2+ levels. Cd2+ or Cu2+ can dramatically influence active fractions and their interactions on AT adsorption.The interactions among active fractions play an important role in controlling the environmental behaviors of AT in aquatic environments.
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  Consolidation effect of splitting grouting on earth dam

  WU Ke, MA Mingyue

  2012, 33(2): 228-232. https://doi.org/10.3969/j.issn.1671-7775.2012.02.021

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  To investigate the consolidation mechanism of splitting grouting for earth dam, the advanced FLAC3D method based on 3-D explicit finite difference method was used to analyze the stability of a certain dam during splitting grouting according to strain hardening model and fluid-solid-coupled theory. The distribution regularities of pore pressure and stress level in dam were analyzed in three stages of grouting, non-grouting and re-grouting. The diffusion shape of pore pressure and features of stress level along different path were investigated to discover the consolidation mechanism of splitting grouting and to evaluate the dam stability. The results indicate that the slurry of splitting grouting is diffused to arround field with grouting axial line as middle line, and forms symmetrical distribution. With the increase of grouting times, the pore pressure in dam deduced by slurry penetrating is increased with enhanced diffusion field. The splitting grouting can effectively solve the internal problems in dam, which improves the stress and increases the impermeable effectiveness.
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  Static behavior of steelconcrete composite beams prestressed with external tendons under monotonic loading

  YANG Tao, XUE Weichen

  2012, 33(2): 233-238. https://doi.org/10.3969/j.issn.1671-7775.2012.02.022

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   According to the monotonic loading experiment of  three specimens, the static behavior of steel-concrete composite beams prestressed with external tendons was investigated. The results show that adding prestressing with external tendons can effectively improve the bending capacity of composite beams with reduced ductility at the same time. Strain distribution at the cross section in pure flexure zone remains approximately linear. Increasing the spacing of studs welded on steel beams can improve  ultimate deformability of prestressed beams with slight effect on bending capacity. With the decrease of  shear connection degree, the slip of studs increases at ultimate load. According to different finite element models of composite beams prestressed with external tendons, the effects of concrete compressive strengthen, effective prestress, external tendons profile and studs spacing on the static behavior of composite beams were discussed. A simplified calculation method of bending capacity was proposed based on prestress effect to provide references for the design and calculation of composite beams prestressed with external tendons.
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  Pinning synchronization of supply chain complex networks with time-varying topological structures and multiple coupling delays

  WANG Shuguo, YAO Hongxing

  2012, 33(2): 239-243. https://doi.org/10.3969/j.issn.1671-7775.2012.02.023

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  To realize the synchronization of supply chain complex networks, the pinning synchronization of supply chain complex networks with time-varying topological structures and multiple coupling delays was investigated to reduce operating cost and improve operating efficiency. Based on Lyapunov stability theory and feedback controller, some sufficient conditions for the synchronization were derived by constructing an effective control scheme. According to the relationships of supply, inventory, sales and prices, a new chaotic dynamic system model was established with rich dynamics behavior, and the supply chain systems were used as network nodes for detailed analysis. By the proposed model, numerical simulation was conducted to verify the proposed scheme.
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  Working vacation queue with closed-down, set-up period and negative customers

  XU Zurun, ZHU Yijuan, LUO Haijun

  2012, 33(2): 244-248. https://doi.org/10.3969/j.issn.1671-7775.2012.02.024

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  In M／M／1 working vacation queue, the strategy of negative customers, closed-down and set-up period was introduced. The set-up period is the time needed for setting up a virtual connection according to signaling protocol. The working vacation period can be considered as a delayed period with a lower service rate than that of busy period. With a strategy of removing customers in the end (RCE), negative customers are regarded as external noise. By quasi birth-and-death (QBD) process and matrix-geometric solution method, the distributions of the stationary queue length and stationary waiting time were obtained. The stochastic decomposition structures of queue length and waiting time in stationary state were proved to achieve the distributions of additional queue length and additional delay. The results can provide basis for optimal design of asynchronous transfer mode (ATM) networks queues.