Table of Content

29 June 2011, Volume 45 Issue 06 Previous Issue    Next Issue

Electrotechnology

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A Hybrid Active Filter for Damping Harmonic Resonance in Large Shipboard Power System 2011, 45 (06):  787-792.  Abstract ( 4048 )   Save  A novel hybrid filtering system was designed. This system is composed of both the largecapacity passive filter and the smallcapacity active filter. Considering the fact that the ship’s multicondition operation may cause the change of topology structure and parameters in power system, hybrid filters were introduced. The largercapacity passive filter is to remove the specific order harmonics, and the smallcapacity active filter is to be used in compensation and system finetuning.  After being verified in the power system of a large ship, the new filter is proven to have high performancetoprice ratio and is suitable to the multicondition operation of large ships.   References | Related Articles | Metrics

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Preparation and Properties of Low Cost Selective Emitter Solar Cells ZHANG Song-1, MENG Fan-Ying-1, WANG Jian-Qiang-1, LIU Feng-2, LI Xiang-2, HUANG Jian-Hua-2 2011, 45 (06):  793-797.  Abstract ( 3156 )   Save Selective emitter (SE) has bcome one of the focus of the PV industry for its high photoelectric conversion efficiency. Using Matlab software, this paper simulated the relation between finger spacing and width to get the minimum energy loss. Under the guidance of the theoretical calculation, we selective emitter solar cells were fabricated whose emitter is fulfilled by printing process. Based on the measuremnt and the analysis of ECV, IV, QE etc., it is found that the SE solar cells are superior to normal solar cells, and the conversion efficiency of the SE solar cell is enhanced by about 1%. References | Related Articles | Metrics

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Property Investigation of a-Si/c-Si Hetero-Junction Structure WANG Jian-Qiang-1, 2 , GAO Hua-2, ZHANG Jian-2, ZHANG Song-1, LI Chen-1, YE Qing-Hao-1, MENG Fan-Ying-1 2011, 45 (06):  798-803.  Abstract ( 6516 )   Save This paper investigated the influence of a-Si/c-Si band offset, amorphous silicon emitter doping concentration and interface defects density on interface property of a-Si/c-Si structure. Band offset in a-Si(N+)/c-Si(P) hetero-junction and a-Si emitter high level doping is very useful for the transformation of recombination mechanism from dangling bond to SRH(Shockly-Read-Hall). AFORS-HET simulation indicates that a-Si(N+) emitter doping level of over 1.5×1020 cm-3 on c-Si(P) is an indispensable condition for achieving high efficiency. Comparing with density of short circuit current, open circuit voltage of a-Si/c-Si structure cell is much more susceptible to interface defect density. References | Related Articles | Metrics

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Hybrid Corrector Interior Point Method for Optimal Power Flow XIE Liang-1, JIANG Xiao-Dong-2, LI Shao-Hua-1 2011, 45 (06):  804-808.  Abstract ( 3843 )   Save  A hybrid corrector interior point method was proposed. The proposed algorithm combines effectively the predictor corrector and centrality correction methods, which optimize the search direction by dynamically choosing the proposition of the corrector direction in Newton direction, which can improve the effect of centrality correction and then speed up the convergence of the algorithm. The algorithm was simulated for IEEE 57, IEEE 118, IEEE 300 bus systems and three real systems. The numerical results demonstrate that, compared with the multiple centrality correction interior point method, the proposed algorithm can lead to convergence with a smaller number of iterations and faster computational time. Moreover, the comparison studies also show that the algorithm can be more robust than that traditional predictorcorrector interior point method and its variants. References | Related Articles | Metrics

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The Model of Ship’s Magnetic Field Extrapolation Based on Neural Network Improved by Particle Swarm Optimization LIAN Li-Ting, XIAO Chang-Han, YANG Ming-Ming, ZHOU Guo-Hua 2011, 45 (06):  809-813.  Abstract ( 4663 )   Save The magnetic anomaly created by ferromagnetic submarines may endanger their invisibility. Nowadays, a new technique called closedloop degaussing system can reduce the magnetic anomaly especially permanent one in realtime. To achieve it, a model which is able to predict offboard magnetic field from on board measurements was required. Many researchers settle the problem by a linear model. A back propagation neural network model was proposed to solve it. The model can escape local optimum thanks to optimizing the initial weight values and threshold values by particle swarm optimization algorithm. The method can avoid many problems from linear model and its high accuracy and good robustness was tested by a mockup experiment. References | Related Articles | Metrics

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A Transmission Line Pilot Impedance Algorithm Based on Fault Total Contents XIA Jing-De, SUO 南Jia-Le, HE Shi-恩, WANG Li, LIU Kai, XU Li-Qiang 2011, 45 (06):  814-820.  Abstract ( 3590 )   Save  A pilot protection algorithm of transmission line based on the fault total content of line both terminals was proposed. According to the exact analysis of  the pilot impedance characteristics based on the fault conponent, this algorithm adequately described the computing result influenced by the load component under various operation condition,and established the reasonable protection tripping setting value. It does not set special protection starting unit; at any time of system running, when the result is less than the protection tripping setting value, the fault is determined as the internal and the protections at line’s two terminals may cooperatively trip; otherwise, the protection is blocked whether the fault occurs or not. The algorithm may ensure the stable and reliable results, has strong ability of resisting transition resistance, shows sensitive operating reaction characterictics and possesses selfselecting phase capacity. It builds 1 000 kV 500 km line model on electromagnetic transients program (EMTP), uses the dynamic model data from Lanzhoudong to Xianyang 750kV, executes the simulations under different faults. The simulation results indicate that this algorithm can correctly judge the aforesaid various fault states. References | Related Articles | Metrics

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A Black Start Scheme Based on VSC-HVDC Tie Line LI Sheng-1, YANG Qi-2, LI Chun-Ye-3 2011, 45 (06):  821-825.  Abstract ( 3762 )   Save  A black start scheme based on voltage source converterbased HVDC(high voltage direct current)(VSC-HVDC) tie line was proposed. The ability of VSC-HVDC to softly energize major power system equipment is proved through simulation by PSCAD software. The voltage and frequency control ability of VSC-HVDC can ensure the process of restoration of the black system to be smoothly without inrush current and transient over voltage. The simulation results indicate that VSC-HVDC tie line is ideal to import black start power by using soft energizing control strategy and the proposed scheme of black start is feasible. References | Related Articles | Metrics

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Simulation Experiment Research for Magnetic Localization Method for Magnetometer Sensor at Seabed ZHANG Chao-Yang, XIAO Chang-Han 2011, 45 (06):  826-830.  Abstract ( 3399 )   Save  The simulation experiment study for the localization methods based on the magnetic components and magnetic gradient was carried out. The result indicates that the magnetic localization method is feasible for the localization of the sensors placed at seabed. When the measuring condition is not good, the precision of the method based on the magnetic components is higher. The engineering condition for the sensor’s localization at seabed in practice was analyzed. The method supplies a novel path for the magnetometer sensor’s localization at seabed in practice. References | Related Articles | Metrics

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Modeling and Simulation of Transverse FluxBased Induction Heating in Transverse Seal of Packaging Machine LI Lei, WANG Shi-Gang, MO Jin-Qiu, WEI Xiao-Hui 2011, 45 (06):  831-836.  Abstract ( 3823 )   Save Due to the issue of temperature distribution of transverse sealing in packaging machine, the temperature field of induction heating was analyzed through numerical modeling and calculation. Based on the principle of transverse flux induction, the equations and boundary conditions of the electromagnetic field and the temperature field were deduced. The process of transverse seal and the structure of aluminumpolyethylene composite package materials were considered. Furthermore, the mathematic and the finite element models of electromagnetic field and temperature field that apply to the transverse sealing of packaging machine were established. Using the finite element software ANSYS, the eddy current field and the temperature field were animated. By analyzing the temperature distribution of different directions in the sealsection of the package material, the simulation results show that the temperature distribution in the actual conditions meets the qualification of transverse seal and provide practical references for engineering application. References | Related Articles | Metrics

Atomic Energy Technology

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Effects of Combustion Modes on Exhaust Particle Size Distributions from a Diesel Engine Fueled with n-Heptane LIU Wei-1, 2 , HUANG Zhen-1 2011, 45 (06):  837-841.  Abstract ( 4398 )   Save Effect of combustion modes (including compression ignition direct injection (CIDI), homogeneous charge compression ignition (HCCI) and compound charge compression ignition (CCCI) combustion) on NSDs of exhaust particles from engines fuelled with n-heptane was studied. The results indicate that the structure of NSDs for n-heptane changes with premixed ratio（rp） obviously. The accumulation mode dominates in CIDI case. With the increase of rp, the accumulation mode decreases, the nucleation mode increases significantly. In HCCI case, the nucleation mode occupies the dominant part of the total particles, and the number concentration of accumulation mode is very low. And the total exhaust particles number concentrations for CCCI and HCCI are obviously higher than those of CIDI. In addition, the number concentration of nucleation mode is highly correlation with HC concentrations. References | Related Articles | Metrics

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Design and Initial Performance Experiments of  Thermoelectric Generator Based on Exhaust Heat of Car QUAN Rui-a, QUAN Shu-Hai-a, b , HUANG Liang-b, DENG Ya-Dong-a, TANG Xin-Feng-c 2011, 45 (06):  842-846.  Abstract ( 5294 )   Save In order to utilize the exhaust heat of car effectively and enhance its fuel economy, a thermoelectric generator was designed to realize power generation, from the initial experiments with different engine speed, the temperature influence factors of exhaust were analyzed, besides, the surface temperature distribution of heat collectors with different flow structure as well as the output performance of thermolelectric modules were tested. The experimental results prove that the shunt device in tail pipeline makes a large thermal resistance during the exhaust heat transmission; prolonging tail’s transmission time and path appropriately can help raise the temperature of heat collector’s surface and enhance the output performance of thermoelectric generator evidently; the temperature distribution of heat collector’s surface with snake flow structure is much more uniform than that with cavity structure. According to the experimental results and analysis above, several improved measures were put forward, which will provide useful guidance to the further research in furture. References | Related Articles | Metrics

Electrotechnology

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Experimental Study on the Infrared Signature Suppression Device of a Marine Gas Turbine Exhaust System TAN Li-Cheng, ZHANG Hui-Sheng, LU Zhen-Hua, SU Ming 2011, 45 (06):  847-850.  Abstract ( 3364 )   Save An experiment was carried out to study the ejector. The impact of the distance of the nozzle and the mixer was tested. Different nozzles were also used. The temperature field on the outlet baseline of the ejector was recorded as well as the static pressure of the main stream. The results indicate that the exhaust temperature is reduced most effectively when the distance ratio a/D reaches 0.875. In addition, decreasing the outlet area of nozzle helps to lower the exhaust temperature but will also increase the resistance of the infrared suppressor. References | Related Articles | Metrics

Atomic Energy Technology

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Experimental Study of Dimethyl-Ether Selective Catalytic Reduction NOx over Ag/Al2O3 Catalyst LIU Jia, CHEN Xiao-Ling, WU Jiao, ZHOU Xiang-Man, ZHANG Wu-Gao 2011, 45 (06):  851-855.  Abstract ( 3300 )   Save  In order to expand the low temperature range of selective catalytic reduction (SCR) NOx by dimethyl-ether (DME), NOx conversion to N2 over Ag/γ-Al2O3catalyst was experimentally studied. The catalyst was prepared by using impregnation method, and the influence of the reaction temperature, the content of Ag, the oxygen concentration, NOx source and the molar ratio of DME/NO were investigated respectively. The results show that Ag/γ-Al2O3displays favorable activity even at 200　°C and the NOx conversion ratio increases at the beginning and then decreases as the temperature increasing. The NOx conversion ratio climbs up and then declines as the oxygen concentration increasing, and the best catalyst activity appears when oxygen content is about 8%. The Ag loading of about 3% can get best catalyst activity, and the DME/NO molar ratio for the highest NOx conversion is 2. The influence of NOx source on NOx conversion is very small. References | Related Articles | Metrics

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Correction Technique of Spacecraft Thermal Network Model on the basis of Node Group Combined Method QIN Wen-Bo, CHENG Hui-Er 2011, 45 (06):  856-860.  Abstract ( 3731 )   Save On the basis of the component of node thermal network equation in spacecraft and combining design feature of actual mechanism, a parametric node group thermal network combined equation whose physical meaning is definite was established and the correction technique of thermal network model for spacecraft was made on this basis. The extrapolated formula for calculating temperature that is based upon hot tests and basic principle of heat transfer can be used for determining those node temperature on which there are not measuring points, so the difficult subject is solved that measuring point in temperature is not enough during hot test and the model correction can not be put into effect. Using this correction model, calculating values whose errors are in permissible range can be conducted. References | Related Articles | Metrics

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Nucleate Pool Boiling Heat Transfer Characteristics of  Refrigerant/Oil Mixture with Diamond Nanoparticles ZHUANG Da-Wei-1, PENG Hao-2, HU Hai-Tao-1, DING Guo-Liang-1, ZHU Yu-1 2011, 45 (06):  861-865.  Abstract ( 5995 )   Save  Nucleate pool boiling heat transfer characteristics of refrigerant/oil mixture with diamond nanoparticles were investigated experimentally. The refrigerant is R113 and the oil is VG68. The experimental conditions include a saturation pressure of 101.3 kPa, heat fluxes from 10 to 80 kW·m-2, nanoparticles concentrations in the nanoparticles/oil suspension from 0 to 15 %, and nanoparticles/oil suspension concentrations from 0 to 5 %. The experimental results indicate that the nucleate pool boiling heat transfer coefficient of R113/oil mixture with diamond nanoparticles is larger than that of R113/oil mixture by maximum of 63.4% under the present experimental conditions, and the enhancement increases with the increase of nanoparticles concentration in the nanoparticles/oil suspension and decreases with the increase of nanoparticles/oil suspension concentration. A correlation for predicting the nucleate pool boiling heat transfer coefficient of refrigerant/oil mixture with nanoparticles was proposed. The predicted values of the new correlation can agree with 94% of the experimental data of R113/oil mixture with diamond nanoparticles in the present study within the deviation of ±20%. References | Related Articles | Metrics

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Study on Thermal Conductivities and Permeabilities of  AC/ENG Consolidated Composite Adsorbents JIN Zhe-Quan, TIAN Bo, WANG Li-Wei, WANG Ru-Zhu 2011, 45 (06):  866-869.  Abstract ( 4876 )   Save In order to improve the heat transfer performance and at the same time not to influence the mass transfer performance of the AC (activated carbon) adsorbent bed, six different sizes of AC grains were studied and five kinds of AC/ENG consolidated composite adsorbents were developed. Meanwhile, thermal conductivity and permeability of samples were tested with steady state method. Under the density of 600 kg/m3, all the thermal conductivities of AC grains has a constant value of 0.36 W/(m·K), while the permeability grows with the size of the grains. The highest thermal conductivity of AC/ENG consolidated composite adsorbents is 2.61 W/(m·K), however, the value drops and permeability grows with the ratio of AC increased. When AC reaches the maximal ratio, 71.4%, the thermal conductivity is 2.08 W/(m·K) which is increased by 5.6 times compared with the AC grains, and the permeability is 51.6 μm2. References | Related Articles | Metrics

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Study on a Flat Plate Solar Air Collector with Baffles XIA Bai-Lin, ZHAO Dong-Liang, DAI Yan-Jun, LI Yong 2011, 45 (06):  870-874.  Abstract ( 4987 )   Save A flat plate solar air collector with baffles was studied. Several factors that have influence on the thermal performance of the solar collectors were analyzed. The paper investigated the relations between the efficiency factor, the heatremoval factor of the solar air collector and the total heat loss coefficient, baffles fin efficiency, air velocity inside the flow channel, the space between baffles, and the height of baffles. Also, the time constant of the collectors was studied. The theoretical formula of the collector’s thermal efficiency was obtained, which can be used for design and application of such kind of collectors. References | Related Articles | Metrics

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Application of BOOST Engine in Hybrid Electric Vehicle Simulation WANG Cun-Lei, YIN Cheng-Liang, WANG Lei 2011, 45 (06):  875-879.  Abstract ( 4924 )   Save The AVL BOOST engine model was developed. The engine universal characteristic was calibrated by modulating the throttle flow rate and combustion model parameters. The BOOST engine can be called by CRUISE in the background. The advantages of BOOST engine were listed. The BOOST engine was integrated in the CRUISE simulation environment under New European Driving Cycle. By analyzing the power and fuel consumption of engine and Integrated Starter-Generator (ISG) under urban and suburb cases, the result shows that the BOOST engine well simulates the engine transient process and can guide the control strategy optimization effectively. References | Related Articles | Metrics

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Unsteady Numerical Investigation of Jet Influence on  the Gas-Solid Crossflow in a Confined Domain CHEN Jin-Cheng, WANG Tong, GU Chuan-Gang, FU Yao 2011, 45 (06):  880-884.  Abstract ( 3325 )   Save The jet influence on the gassolid crossflow in a confined domain was investigated by unsteady numerical computation. By analyzing the numerical results, backflow was found in the jet wake. A series of vortex occurring, spiraling and breaking phenomena were also found in the flow. By supervising some critical points in the flow, the vortex shedding was found to be periodic which is a kind of the Karman vortex street. By tracking the particle path and analyzing the particle concentration field, particles on the 10 μm scale were found forming a clear and persistent low concentration region in the flow field. The simulated results agree well with the experimental. The numerical simulation data untested in the experiment were analyzed to enhance the understanding of the flow characteristic and particle concentration, providing reference to the application of wall jet controlling method in fluid engineering. References | Related Articles | Metrics

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Development on Master-Slave Electronic Control Unit Control System of Diesel Engine SONG Xue-Hua-1, WENG Yi-Wen-1, YUAN Yin-Nan1, WU Di-2, WANG Hong-2, ZHANG Yu-Hua-2 2011, 45 (06):  885-889.  Abstract ( 4082 )   Save This paper presented a master-slave electronic control unit (ECU) control system of diesel engine based on two 6-cylinder engine control units, which implements control on a 12-cylinder locomotive diesel engine. The master and slave ECUs have the same hardware and software architecture, and the identification of master or slave ECU only depends on their physical positions, therefore they have fully interchangeability. The paper described the hardware architecture, the logic of status identification, the communication agreement and engine control strategy of the master-slave ECU. The results of experiments prove the rationality of the control system. The 12V280 locomotive engine works well and the speed is stable in experimental conditions, as well as the errors can be controlled within 0.5%. References | Related Articles | Metrics

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Boiling Heat Transfer Characteristics of Nanofluids in  a Thermosyphon Loop LIU Zhen-Hua, YANG Xue-Fei 2011, 45 (06):  890-894.  Abstract ( 10407 )   Save An experimental study was performed to understand the boiling characteristics of CuOwater nanofluids in a thermosyphon loop. Experiments were carried at varied subatmospheric pressures. Effects of the mass concentration and the operating pressure on the heat transfer characteristics were mainly discussed. The results indicate that nanofluids can enhance both the boiling heat transfer coefficient (HTC) and the critical heat flux(CHF). The effect of the operating pressure on the heat transfer coefficient is obvious, while the effect is weak on CHF. There exists an optimal mass concentration of nanoparticles, which corresponds to the largest HTC enhancement. The HTC enhancement results from the effects of both the coating layer and the working fluids. The CHF enhancement results mainly from the coating layer formed by nanoparticles during the heating process. References | Related Articles | Metrics

Metallography and Metallurgical Technology

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Fuzzy Adaptive Control Optimization of  High Hardness Sphere Grinding Based on Dynamic Threshold LI Dong-Dong, XU Ming-Ming, HU De-Jin, XU Li-Ming 2011, 45 (06):  895-900.  Abstract ( 3206 )   Save  In order to avoid the scratches on the workpiece in the high hardness sphere grinding, the grinding force was got indirectly by measuring the motorized spindle current which is used as a feedback to control the grinding force of the high hardness sphere grinding. A fuzzy adaptive control optimization strategy based on dynamic threshold (DTFACO) was applied according to the features of the grinding force generated in the high hardness sphere grinding process. The current threshold can be auto obtained and rectified on line. The depth of cut and the swing angular speed which affect the grinding force can also be adjusted on line by fuzzy strategy to maintain the grinding process stable. The experimental results indicate that the fuzzy adaptive control optimization strategy based on dynamic threshold can decrease the roughness of the workpiece without decreasing the grinding efficiency. It can avoid the scratches on the workpiece in the high hardness sphere grinding. References | Related Articles | Metrics

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Simulation and Prediction of the Maximum Temperature in  sphere Grinding with Improved BP Neural Network Model JIANG Tian-Yi, HU De-Jin, XU Kai-Zhou, XU Li-Ming 2011, 45 (06):  901-906.  Abstract ( 3818 )   Save Based on the outstanding characteristic of nonlinear convergence of neural network, an improved BP neural network was established. Orthogonal experiments were carried out to provide batch training samples for the network. And the LevenbergMarquardt algorithm was used to minimize the errors of the network. In addition, the Bayesian regularization was employed to optimize the combination of squared errors, weights and the sum of squared threshold. The experimental results show that the improved BP neural network has fast rate of convergence, strong generalization capability and good stability, which can simulate and predict the maximum temperature in sphere grinding with high accuracy.   References | Related Articles | Metrics

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Effect on Truing and Dressing Non-metal Bond  Diamond Grinding Wheel in Air XU Ming-Ming, LI Dong-Dong, HU De-Jin 2011, 45 (06):  907-910.  Abstract ( 4069 )   Save  In order to overcome the weak conductivity of non-metal bond, a method that smears the wheel surface using conductivity medium was used. Experiments on dressing resin bonded diamond grind wheels were carried out on a diesinking electrical discharge machine. The influences of different electrical parameters on wheel dressing efficiency were studied. The diamond wheel topographies before and after electrical discharge dressing were observed by VH-800 three dimension digital microscope. The wheel profiles before and after dressing were observed. The results of electrical discharge dressing under different electrical parameters were compared.  References | Related Articles | Metrics

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Strengthening of 7085 Al Alloy by Large Strain Deformation with the Alloy Preheated at Solution Treatment Temperature XU Xiao-Jing, WU Gui-Chao, WANG Bin, ZHANG Fu-Bao, LUO Yong…… 2011, 45 (06):  911-914.  Abstract ( 4281 )   Save A new precedure to prepare ultra-high strength aluminum alloy was proposed. The procedure is carried out through subjecting the aluminum alloy pre-heated at solid solution treatment temperature to the large strain deformation (equalchannel angular pressing, i.e. ECAP) with appropriately quick cooling of the alloy. This approach can process low ductility aluminum alloy and has the potential of adding dislocation strengthening and other strengthening together to significantly strengthen the alloy. The experimental results show that the ECAP-resulted strengthening for the 7085 Al alloy preheated at solid solution treatment temperature is related with the temperature of the used ECAP die. Compared to the ECAP proceesing with the ECAP die temperature of 400 °C, the ECAP proceesing with the ECAP die temperature at room temperature leads to a considerable increase in strengthening. The theorical calculation based on Taylor equation on strength dislocation density relationship indicates that the dominant factor for leading to the considerable increase in strengthening is not dislocation strengthening increase, but other strengthening mechanisms that are believed to be precipitation strengthening and grain boundary/subgrain boundary strengthening.   References | Related Articles | Metrics

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Generation and Control Method of EDM Mill Servo Track Based on Programmable Multi-axis Controller HUANG He, BAI Ji-Cheng, LU Ze-Sheng 2011, 45 (06):  915-919.  Abstract ( 4145 )   Save  An NC system based on PC and PMAC (Programmable Multi-Axis Controller) was constructed for EDM mill to meet the need of adjusting velocity and direction of movement relying on gap statement in the process. According to real-time requirements, system tasks were assigned to PC and PMAC. This improved system real-time feature and reliability. A couple of motion NC programs for same track with different directions were generated combined with PLC program to realize the backward movement of EDM mill. According to machine gap status, the time based function of PMAC was used to control electrode motion velocity. The direction and velocity of track movement were totally controlled by PMAC. This reduces   computing burden of the host PC and improves the real time feature of the processing. 3D cavities were machined to prove the effectiveness of the methods developed in this paper. References | Related Articles | Metrics

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Experimental Research on Normal Bonding Strength and Hole Expanding Capability of Laminated Vibration Damping Steel Sheet CHEN Jie-Shi, CHEN Jun, HUANG Yuan-Chen, WANG Yong 2011, 45 (06):  920-923.  Abstract ( 4080 )   Save The failure of LVDSS (laminated vibration damping steel sheet) is different from single steel sheet because of structural particularity. The delimination of interface and fracture of skin sheets are the common failure of LVDSS. The experimental method and the specimen were designed to test the normal bonding strength between the skin sheets of LVDSS. Furthermore, hole expanding experiments of LVDSS were also conducted. The normal bonding strength and the average hole expanding ratio were obtained, which provide useful failure criterion for numerical simulation. The experiment indicates that the difference between LVDSS and single steel sheet is not only the difference of material property parameters and process parameters but also the difference of failure mode. New failure criterion and examining approaches should be developed for the wide and successful application of LVDSS. References | Related Articles | Metrics

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A Model to Predict Temper Rolling Force of  Thin Gauge Strip with RBF Neural Networks DUAN Xue-Hou, WANG Shi-Gang, XU Wei, TANG Cheng-Long 2011, 45 (06):  924-928.  Abstract ( 3646 )   Save The temper rolling process of thin gauge strip has the features of thin thickness and small reduction, thus it is difficult to calculate its temper rolling force and get a highprecision value. Aiming to solve this problem, this paper established a mathematical model to calculate its temper rolling force based on parameters modification. Meanwhile, the paper predicted the calculation error of the mathematical model above by using RBF neural networks in order to improve its precision further, and completed the modification for temper rolling force model by combining the calculation error and calculated values of original mathematical model. The offline simulation indicates that the precision of new model of temper rolling force for thin gauge strip can reaches 6% after twice modification by its modified parameters and RBF neural networks, which makes it have high value of application in real project. References | Related Articles | Metrics

Biomedical Engineering

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Experimental Study of Transfersomes in Hypertrophic Scar Penetration in Vitro ZHANG Zhen-1, WO Yan-1, ZHANG Yi-Xin-1, MAO Xiao-Hui-2, QIAN Yun-Liang-1, WANG Dan-Ru-1, HE Rong-3, CUI Da-Xiang-3 2011, 45 (06):  929-934.  Abstract ( 3827 )   Save Hypertrophic scar has its special tissue structures. Drug penetration in the local is the key role of topical effect. The purpose of this study is to characterize a novel transdermal delivery carrier: transfersomes containing 5fluorouracil (5-FU) to investigate the delivery of drugs from transfersomes in human hypertrophic scar in vitro. Cumulative 5FU that permeated hypertrophic scar and skin after 24 h is: transfersomes via hypertrophic scar (T-Scar) > 5-FU solution via hypertrophic scar (CScar) > transfersomes via skin (T-Skin) > 5-FU solution via skin (C-Skin). The depositions of 5FU and intensities of fluorescence after application for 24 hours are: T-scar> T-skin> C-scar> C-skin. Conclusively, the delivery ability of transfersomes is most efficient in human hypertrophic scar. The test results indicate that transfersome is a high efficient carrier in hypertrophic scar. References | Related Articles | Metrics

Mechanical Engineering

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Research of Aerodynamic Noise Source in Tip Region of Axial Fans with Circumferential Skewed Blades at Off-Design Conditions JIN Guang-Yuan-1, 2 , 欧Yang-Hua-1 , HU Bin-Bin-1, WU Ya-Dong-1, DU Chao-Hui-1 2011, 45 (06):  935-939.  Abstract ( 4511 )   Save Aerodynamic noise source generated by tip leakage flow in circumferential skewed axial fans was studied by CFD simulation and experiments under offdesign conditions. Relationship between tip leakage flow and aerodynamic noise was analyzed based on vortexsound theory of low speed homentropic flow. Synergy between acoustic source and tip leakage vortex was discussed. Pressure test on casing wall and acoustic far field test were conducted to find how the different circumferential skewed direction control acoustic characteristics. The results show that the acoustic source generated by tip leakage vortex of circumferential skewed blades is an important noise source under offdesign conditions. The angle between velocity vector and vortex vector controls the strength and the distribution of the acoustic source in tip clearance region. The acoustic source in tip clearance region is related with the acoustic far field under offdesign conditions. References | Related Articles | Metrics

Mathematics

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Radial Vibration Characteristics of an Annular Ultrasonic Concentrator with n-th Power Thickness Variations LIU Shi-Qing-1, SU Chao-1, YAO Ye-2 2011, 45 (06):  940-944.  Abstract ( 3068 )   Save The radial vibration of an annular ultrasonic concentrator with nth power thickness variation was studied. Based on the electromechanical analogy, the radial equivalent circuit and the frequency equation were derived. The displacement amplitude magnification coefficient of the concentrator was obtained. The relationships between the resonance frequency, the radial displacement amplitude magnification coefficient of the concentrator at the first and second order vibration modal and the radius ratio of it were analyzed. By numerical calculation, it is shown that the radial fundamental frequency of the concentrator decreases as the radius ratio increases. While a minimum of the second order resonance frequency appears when the radius ratio of the annular concentrator increases. Moreover, the displacement amplitude magnification coefficient of the concentrator increases as the power of nth increases, and the amplitude magnification coefficient at the second order resonance is much greater than that of the first order resonance. It is illustrated that the theoretical results are in good agreement with the FEM simulations. References | Related Articles | Metrics