Archive

15 September 2015, Volume 36 Issue 9 Previous Issue    Next Issue
---
Information & Control
Materials & Metallurgy
Mechanical Engineering
Resources & Civil Engineering
Management Science


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Information & Control

Select

Adaptive Routing Algorithm of Asynchronous 2D-Torus Network-on-Chip LI Zhen-ni， LI Jing-jiao， FANG Zhi-qiang， WANG Jiao 2015, 36 (9):  1217-1221.  DOI: 10.3969/j.issn.1005-3026.2015.09.001 Abstract ( 696 )   HTML   PDF (496KB) ( 733 )   To solve the problem of easily blocking and the waste of routing resources of asynchronous network-on-chip (NoC) using determined routing algorithm， an adaptive routing algorithm suitable for asynchronous NoC using 2D-Torus topology was proposed based on the asynchronous circuit design methodology. A test platform was established， and the function and performance of the asynchronous NoC were analyzed， verified and tested. The experimental result indicates that the adaptive routing algorithm proposed can meet the requirement of self-adaptive routing， and can effectively reduce the transport delay. The asynchronous NoC system proposed supports multi-directional data communication， multi-channel parallel data communication and equal arbitration of data request， and it can call the IP core to perform the corresponding data processing. References | Related Articles | Metrics

Select

A New Relay-Based End-to-End Multipath Transmission Control Protocol CHEN Xiao， LEI Wei-min， ZHANG Wei， GUAN Yun-chong※ 2015, 36 (9):  1222-1226.  DOI: 10.3969/j.issn.1005-3026.2015.09.002 Abstract ( 528 )   HTML   PDF (776KB) ( 645 )   The methods of building and applying multipath for transmission become the hot spot of current network control protocol research. There is no perfect solution for real-time media data multipath transmission control protocol. In order to tackle the problems in the practical situations， a new relay-based end-to-end multipath transmission control protocol based on relay was proposed in the paper. In the protocol， the relay is used as the important component to build and manage multipaths. The format of message and the results of simulation test related to the protocal are presented in detail. The simulation results show that when the protocol is used to transmit real-time audio and video media data， compared with single-path transmission protocal， the transmission delay， data loss rate and transmission quality are improved significantly. References | Related Articles | Metrics

Select

An Improved ViBe Algorithm for Moving Object Detection XU Jiu-qiang， JIANG Ping-ping， ZHU Hong-bo， ZUO Wei 2015, 36 (9):  1227-1231.  DOI: 10.3969/j.issn.1005-3026.2015.09.003 Abstract ( 897 )   HTML   PDF (472KB) ( 987 )   Background differencing is the commonly used method for the detection of moving objects in the static background， and the ViBe algorithm is the main modeling approach. In order to solve the problem about low rate of ghost elimination caused by the execution of ViBe algorithm， an improved ViBe algorithm combining with frame difference method is proposed. By using the frame difference method， the ghost pixel is judged according to the changes in time domain for related pixel value， which can improve the rate of ghost elimination. Since the specific condition of each pixel cannot be reflected with the fixed threshold， a method with self-adaptive threshold is proposed. The threshold of each pixel is set according to the change of the pixel value， which can improve the accuracy of foreground detection. The experimental results show that the ViBe algorithm combining with frame difference technology can be used to eliminate the ghost in the detection results more quickly， and the foreground can be detected more accurately using the ViBe algorithm with self-adaptive threshold. References | Related Articles | Metrics

Select

Dynamic Evolution Analysis of the Earthquake Network Based on the Time-Space Influence Domain ZHAO Hai， ZHANG Ya， HE Xuan， ZHAO Nan 2015, 36 (9):  1232-1236.  DOI: 10.3969/j.issn.1005-3026.2015.09.004 Abstract ( 569 )   HTML   PDF (642KB) ( 737 )   Based on the earthquake network of the time-space influence domain， the topology of seismicity around the main shock was analyzed for the network’s dynamic behaviors. It was found that the scale and the entropy were small while the modularity was big before the main shock; the scale increased greatly， the entropy jumped to a high value and the modularity reached a minimum value after the main shock. Meanwhile， the multi-parameter evolution of the topology of seismicity in 1992 was analyzed， whose results showed that the earthquake network exhibited a inner dynamic behavior. In addition， the modularity took a maximum value， the entropy had a minimum value， and they presented good negative correlation. References | Related Articles | Metrics

Select

Dissipation Analysis of Internet Topology Structure LIU Xiao， ZHAO Hai， WANG Jin-fa， HE Xuan 2015, 36 (9):  1237-1241.  DOI: 10.3969/j.issn.1005-3026.2015.09.005 Abstract ( 633 )   HTML   PDF (655KB) ( 714 )   Mechanical and flexible structural orders emerge in the Internet topology. The researches describing the dissipative structural order and related topics are very important in the redesign of the Internet， and it is also of great importance in the field of predicting the evolution of Internet topology. IPv4， IPv6 and AS-level network topologies data which authorized by cooperative association for Internet data analysis (CAIDA) are used in this paper， and the relationships among the network structural orders and the size and connectivity of the network are discussed， the results show that all the 3 kinds of network are of dissipative structures， which behave both centralization and equalization， and their orders are continuously evolving in the process of dissipation. The positive correlativity among the network structural orders and the size and connectivity of the network size shows that the network structural order is gradually dissipated in the development process of the Internet. References | Related Articles | Metrics

Select

High Performance Routing Algorithm Based on Geographic Location Prediction SHA Yi， GUO Zi-qiang， ZHU Li-chun， ZHANG Zhi-wei 2015, 36 (9):  1242-1245.  DOI: 10.3969/j.issn.1005-3026.2015.09.006 Abstract ( 555 )   HTML   PDF (374KB) ( 677 )   Based on the ARIMA prediction model， an efficient routing algorithm was put forward. In this algorithm， a node could obtain the interference-aware expected transmission time (iETT) by measuring the packet loss rate and expected transmission number with the successful forward and reverse forwarding rate as well as the speed of data transmission. Thus， the L-iETT could replace the shortest hop criterion of the DSR routing algorithm. The ARIMA model was introduced to predict the movement location of the next node so as to prevent the network packet loss caused by frequent link fractures and select in advance the most stable path to data transmission before link failure. The simulation results showed that the routing algorithm criterion increases by 6%~9% compared with the DSR throughput and the average end-to-end delay reduces by 2%~6% so that the network’s overall performance can be improved. References | Related Articles | Metrics

Select

Soft Tissue Parameter Measurement Based on Pressure Acquisition and FEM Model LIAO Xiang-yun， YUAN Zhi-yong， CHEN Er-hu， ZHENG Qi 2015, 36 (9):  1246-1250.  DOI: 10.3969/j.issn.1005-3026.2015.09.007 Abstract ( 585 )   HTML   PDF (455KB) ( 699 )   A method of soft tissue parameter measurement was proposed based on pressure acquisition and FEM model， which included a soft tissue parameter measurement platform based on optical motion tracking system and pressure acquisition module. The soft tissue deformation was reconstructed in three dimensions， and the pressures on the soft tissue were obtained by an ARM acquisition board with a pressure sensor whose precision was calibrated with the BP neural network. Then a tetrahedral finite element model was built to calculate the initial parameters (Young’s modulus and Poisson rates) of the soft tissue and a parameter reference model was proposed to obtain the modified parameters whose accuracy was verified experimentally. The experimental results indicated the average relative deviation between calculated deformation and measured deformation is 1.03%~1.60%， which satisfies the accuracy requirements of soft tissue deformation in practical engineering applications. References | Related Articles | Metrics

Select

An Improved Local Inference Algorithm for Multiply Sectioned Bayesian Networks ZHAO Jian-zhe， LI Kai 2015, 36 (9):  1251-1255.  DOI: 10.3969/j.issn.1005-3026.2015.09.008 Abstract ( 583 )   HTML   PDF (293KB) ( 711 )   Due to the temporal and spatial complexity in the local inference of multiply sectioned Bayesian networks (MSBN)， an improved algorithm for the local inference of MSBN was proposed. The algorithm redefined the model of MSBN with an object-oriented language. Combined with the concept of vertex degree in graph theory， the algorithm was optimized based on the joint tree algorithm. Considering that the outcome of triangulation was not single， the improved algorithm offered a general solution， which helped to convey message faster and greatly shorten inference time. Finally， an instance of the algorithm was given for experimental analysis， whose results showed that the improved inference algorithm significantly reduces both temporal and spatial complexity. References | Related Articles | Metrics

Materials & Metallurgy

Select

Influence of Annealing Time on the Microstructure Evolution in the Medium-Mn Hot-Rolled TRIP Steel LI Zhi-chao， DING Hua， CAI Zhi-hui， LI Mei-ling 2015, 36 (9):  1256-1260.  DOI: 10.3969/j.issn.1005-3026.2015.09.009 Abstract ( 588 )   HTML   PDF (1113KB) ( 720 )   Microstructure evolution and mechanical properties of a hot-rolled Fe-6Mn-3Al TRIP steel were studied by using the heat treatment process of quenching and annealing for different time (ART). The results showed with the increase of annealing time， the grain size of austenite increases and the stability decreases. Part of the austenite transforms into martensite in the cooling process. After annealing for 10min， the performance of the experimental steel is optimal. The volume fraction of austenite is 50.3%， the ultimate tensile strength is 765MPa and the total elongation is 49.1%. The content of the austenite decreases and the martensite increases after deformation. The TRIP effect is most obvious after annealing for 10 min. The volume fraction of austenite reduces from 50.3% to 11% after deformation. The transformation rate of austenite is 78%. References | Related Articles | Metrics

Select

Controllable Preparation of α-Fe2O3 Particles with Different Morphology HU Jian-she， SUN Nan， LI Song， QIN Gao-wu 2015, 36 (9):  1260-1264.  DOI: 10.3969/j.issn.1005-3026.2015.09.010 Abstract ( 533 )   HTML   PDF (709KB) ( 671 )   A series of the iron oxide particles with different morphology were prepared by changing the hydrothermal synthesis conditions， type and addition amount of surfactant. The morphology， size and crystal form of the iron oxide particles were characterized using scanning electron microscopy and X-ray diffraction measurement. The results showed that the reaction temperature， reaction time， pH value and reactant amount could affect morphology and size of the iron oxide particles. The iron oxide particles with sheet-like， cubic， burger-like， shuttle-like， rectangular， walnut-like， hexagonal prism and hollow morphology can be obtained by adjusting the additive type and other experimental conditions. The controllable preparation of the iron oxide particles with different morphology is realized. References | Related Articles | Metrics

Select

Low-Temperature Siliconizing of Silicon Steel Subjected to Shot Peening and Effect of Siliconizing Parameter LIU Gang， MO Cheng-gang， SHA Yu-hui， ZUO Liang 2015, 36 (9):  1265-1269.  DOI: 10.3969/j.issn.1005-3026.2015.09.011 Abstract ( 597 )   HTML   PDF (535KB) ( 731 )   A silicon steel was treated by using shot peening (SP) and followed by solid powder siliconizing treatment to investigate the possibility of simplify siliconizing operation by means of surface nanocrystallization and effect of siliconizing parameter. The microstructural evolution was examined by using transmission electron microscopy， scanning electron microscopy and X-ray diffraction， respectively. Experimental results showed that nanocrystallines (of about 10 nm in size) with random orientations form in the top surface layer of SP sample. After the siliconizing treatment in Si powder+halide at 550℃， a compound layer forms on the SP sample， and its thickness increases with the increasing of the siliconizing temperature and the duration at higher temperature， however keeps unchanged with the increment of halide content. The compound layer consists of FeSi and Fe3Si phases. The higher temperature and halide content / lower temperature and halide content are helpful for the formation of FeSi/Fe3Si phases， respectively. References | Related Articles | Metrics

Select

Effects of Composition on Corrosion Resistance of MgO-Al2O3-C Refractory ZHAO Shu-mao， MEI Guo-hui， ZHANG Jiu， XIE Zhi 2015, 36 (9):  1269-1272.  DOI: 10.3969/j.issn.1005-3026.2015.09.012 Abstract ( 531 )   HTML   PDF (578KB) ( 620 )   The proportion of raw materials has an important influence on corrosion resistance of MgO-Al2O3-C refractory besides working conditions. MgO-Al2O3-C samples were prepared with different type of fused magnesia and various amounts of Al2O3 and graphite. Their corrosion rates in CaO-rich slag were investigated by rotating the samples in the molten slag. The effect of composition on the corrosion resistance of MgO-Al2O3-C refractory was studied. The results showed that the corrosion resistance decreases as the magnesia’s impurity increases. And with the increase of Al2O3 and graphite content， the corrosion resistance increases firstly and then decreases. Excessive Al2O3 results in viscosity decrease of slag， and excessive graphite results in porosity increase. Thus， for MgO-Al2O3-C refractory that used under CaO-rich slag， the ideal Al2O3 content is 10%~30% and the graphite content is 10%~20%. References | Related Articles | Metrics

Select

Effect of Sulfur Mass Fraction on Inclusions in Steel E36 Deoxidized by Titanium and Zirconium ZHAN Dong-ping， TANG Lei， JIANG Zhou-hua， ZHANG Hui-shu 2015, 36 (9):  1273-1277.  DOI: 10.3969/j.issn.1005-3026.2015.09.013 Abstract ( 696 )   HTML   PDF (742KB) ( 634 )   In order to study the effect of sulfur mass fraction on inclusions in steel E36 deoxidized by titanium and zirconium， steelmaking experiments of three heats of steel E36 were done in a MoSi2 furnace with 70mm×100mm MgO crucible at 1873K. The results showed that most of the inclusions in steel E36 deoxidized by titanium and zirconium are spherical inclusions of TiO○x and ZrO2 coated by MnS. The typical inclusions are Al2O3-TiO○x-MnS， MgO-SiO2-Al2O3， Al2O3-SiO2-TiO○x-ZrO2 and TiO○x-SiO2-Al2O3-MnS. With the increasing of the sulfur mass fraction in steel， the inclusion percentages with the diameter less than 10μm increase to 99.5%; the average diameter of the inclusions reaches 2.3μm from 1.7μm; the sulfur mass fraction in the inclusions and the area of MnS in single inclusion are also bigger， the area is 0.15% when w［S］ is 0.001 5%， and it becomes 0.72% when w ［S］ is 0.011%. References | Related Articles | Metrics

Select

Influencing Factors Optimization on the Compressive Strength of High Iron Bauxite Hot Briquettes with Response Surface Methodology LIU Zheng-gen， CHU Man-sheng， WANG Zheng， WANG Hong-tao 2015, 36 (9):  1278-1282.  DOI: 10.3969/j.issn.1005-3026.2015.09.014 Abstract ( 668 )   HTML   PDF (554KB) ( 615 )   The central composite design with response surface methodology was used to systemically research the effects of process parameters such as coal additive amount， ore particle size and coal particle size and their interaction on the compressive strength of high iron bauxite hot briquettes (HIBHB). The relevant mathematical prediction model was established as well. The results showed that these process parameters had significant effects on the compressive strength of HIBHB， ranking from coal additive amount， ore particle size to coal particle size. The established mathematical model with a correlation coefficient of 0.9589 could predict the changing rules for the compressive strength of HIBHB. Based on the model， the process parameters were optimized as follows: coal additive amount 19.0%， ore particle size 96μm and coal particle size 80μm. Under the manufacturing condition of optimized process parameters， the compressive strength of HIBHB was 1024.3N， very close to the predicted value of 1000N by the model. The difference between the experimental value and the predicted value was simply 2.43%， which indicated that the mathematical model could help to optimize the production process for HIBHB. References | Related Articles | Metrics

Select

Study on Blast Furnace Slag System of Vanadium-Titanium Magnetite Under Neutral Atmosphere CHU Man-sheng， FENG Cong， TANG Jue， LIU Zheng-gen 2015, 36 (9):  1283-1287.  DOI: 10.3969/j.issn.1005-3026.2015.09.015 Abstract ( 506 )   HTML   PDF (1021KB) ( 689 )   The components of practical blast furnace (BF) slag of vanadium-titanium magnetite were adjusted by adding pure chemical reagents. The effects of binary basicity， MgO， Al2O3， TiO2 and V2O5 on the metallurgical properties of experimental slag were studied under neutral atmosphere. The results showed that with increasing content of basicity and MgO， the melting temperature (t○m)， initial viscosity (η○0) and high-temperature viscosity (η○h) of slag first decrease and then increase. As increasing Al2O3 content， t○m increases， η○0 first decreases and then increases， η○h increases. When increasing TiO2 content， t○m increases， η○0 and η○h decrease. The viscosity flow activation energy of slag increases and the heat stability of slag becomes worse. With increasing V2O5 content， t○m first decreases and then increases， η○0 and η○h increase. The suitable BF slag for smelting vanadium-titanium magnetite is: binary basicity 1.15，MgO 13%， Al2O3 13%， TiO2 7%，V2O5 0.30%. References | Related Articles | Metrics

Select

Modification of Corncob Activated Carbon and Adsorption Properties of CO2 DU Tao， FANG Xin， LIU Li-ying， ZHANG Sheng-dong 2015, 36 (9):  1288-1292.  DOI: 10.3969/j.issn.1005-3026.2015.09.016 Abstract ( 695 )   HTML   PDF (597KB) ( 708 )   The method to improving the adsorption properties of CO2 of as-synthesized corncob activated carbon was investigated. The oxidative modification and reductive modification were carried out. The results showed the content of carbon (C) reduces by approximate 10% during the process. The samples modified by nitric acid and nitrates obtained more oxygenic functional groups on the surfaces. Those treated with carbonates acquired additional CO2-3 as well. Those improved via ammonia introduced a mass of amidogens. To sum up， oxidative and reductive modifications are well applied to the synthetic activated carbons. In particular， the CO2 adsorbing capacities of samples modified with Ca(NO3)2 and Na2CO3， compared with that of the raw activated carbon， increase by 21.2% and 28.5%， respectively. Therefore， the reductive modification with carbonates such as Na2CO3 performs better in improving the CO2 adsorption capacities of the as-synthesized corncob activated carbon. References | Related Articles | Metrics

Select

Discrete Element Simulation of Solid Flow Pattern and Transient Features of Burden Descending in COREX Shaft Furnace ZHOU Heng， YOU Yang， LUO Zhi-guo， ZOU Zong-shu 2015, 36 (9):  1293-1297.  DOI: 10.3969/j.issn.1005-3026.2015.09.017 Abstract ( 516 )   HTML   PDF (1116KB) ( 652 )   A mathematical model based on discrete element method (DEM) was developed to investigate the behaviors of solid particulate motion in a COREX shaft furnace model from particle-scale view. The solid flow pattern and transient features of burden were simultaneously analyzed， especially the transient behavior of velocity and stress distribution were calculated. The results showed that the solid flow in COREX shaft furnace can be divided into three different flow regions: plug flow zone， quasi-stagnant zone and converging flow zone. The transient behavior of velocity distribution indicates that there are two types of velocity waves in the furnace. One is a downward wave caused by charging and the other is upward from bottom caused by discharging. The normal stress has a minor change with time. A high stress field exists on the top of the guiding cone， while for the furnace without guiding cone， the particles in the lower central zone present strong normal stress. On the contrary， the particles exhibit weak normal stresses in the converging flow zone. References | Related Articles | Metrics

Select

Analysis of Al-Contents in Social Stock and the Regeneration Index of Depreciated Aluminum Products in China YUE Qiang， DU Yan， WANG He-ming 2015, 36 (9):  1297-1301.  DOI: 10.3969/j.issn.1005-3026.2015.09.018 Abstract ( 673 )   HTML   PDF (550KB) ( 693 )   Aluminum production and consumption have increased quickly in China in recent years， while bauxite is in severely shortage and has to been imported from overseas. With the increment of aluminum social stock， the old scrap will become larger and play a greater role in aluminum industry. The social stock of aluminum， average age， old scrap recovery rate and regeneration index were analyzed. The results showed that social stock of aluminum in China increased from 7.23 million tons to 103.55 million tons in the period 1990~2010. The average age of aluminum products in social stock was about 4.3 years， and the regeneration index of depreciated aluminum products and recovery rate of aluminum social stock were 0.0747t/t and 1.17 percent， respectively， in 2010. Three scenarios analysis for different aluminum consumption conditions were carried out， and under the third scenario: the amount of aluminum social stock will reach 6 hundred million tons in 2035 and keep constant at 5.7 hundred million tons in 2055. In the year 2040， the average age of aluminum products in social stock will reach its maximum value at 7.13 years， the regeneration index of depreciated aluminum products and recovery rate of aluminum social stock will also get their maximum value in the same year， and the values were 0.79t/t and 5.05%， respectively. The analyzing results will give some references for the policy making of aluminum industry. References | Related Articles | Metrics

Select

Synthesis of Copper Nanowires by Electroless-Chemical Deposition ZHANG Xiao-yan， WANG Ming-hua， ZHAI Yu-chun 2015, 36 (9):  1302-1305.  DOI: 10.3969/j.issn.1005-3026.2015.09.019 Abstract ( 667 )   HTML   PDF (443KB) ( 704 )   Electroless chemical deposition instead of electrochemical deposition was adopted to prepare copper nanowires in that electroless chemical deposition neither has to sputter a layer of gold as cathode on one side of the through-hole template nor supplies power to complete the synthesis of nanowires. The effect of sensitizing solution and deposition time on the preparation of copper nanowires was discussed. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were applied to observe the morphologies of the samples. The experimental results showed that nanoparticles were firstly formed in the process of deposition， and then they gradually merged to form nanotubes and nanowires with the increase of deposition time. The copper nanowires prepared by electroless chemical deposition were multi-crystal structures. In the templateless case， the copper atoms grew to form petal-like structures by autocatalysis. The sensitizing solution diluted with 95% ethanol was more stable than that with water， but it was less likely to form nanowires compared to the sensitizing solution with water in about the same deposition time. References | Related Articles | Metrics

Select

Behaviors of Precious and Base Metals in Process of Copper Anode Slime Hydrometallurgical Treatment JIN Zhe-nan， MA Zhi-yuan， YANG Hong-ying， LIU Xin-jian 2015, 36 (9):  1305-1309.  DOI: 10.3969/j.issn.1005-3026.2015.09.020 Abstract ( 744 )   HTML   PDF (747KB) ( 876 )   The low efficiency and serious pollution are the main problems needed to be solved in the process of copper anode slime treatment for a copper smelting enterprise. A process of hydrometallurgical treatment of copper anode slime was proposed. The behaviors of the precious and base metals such as Pb， Cu， Ag， Au， Pt and Pd were studied using the substance flow analyses. The results showed that Pb， Cu， Ag and Au distribute intensively in the process of hydrometallurgical treatment and the effects of Pb and Cu on the hydrometallurgical treatment of copper anode slime are insignificant. Almost 99% Au and 99% Ag are enriched in the crude Au powders and crude Ag powders， respectively. The direct recovery rates of Pt and Pd are low and Pt and Pd distribute dispersedly in the Pt-Pd concentrate， Pt-Pd precipitated solution and Pb leached residue. References | Related Articles | Metrics

Mechanical Engineering

Select

Design of Wind Turbine Airfoils Based on General Profile and Mesh Reconstitution SUN Zhen-ye， CHEN Jin， XIE Yi， JIANG Chuan-hong 2015, 36 (9):  1310-1315.  DOI: 10.3969/j.issn.1005-3026.2015.09.021 Abstract ( 588 )   HTML   PDF (820KB) ( 705 )   Most of the airfoil representations do not have a large enough domain to select the optimal airfoil in that they mainly depend on control points and initial airfoils. Based on the parametric profile representation， which originated from Joukowski conformal transformation， an improved genetic algorithm was designed to obtain airfoils with a high lift-to-drag ratio. ICEM and FLUENT were coupled to generate airfoils， reconstruct mesh， set boundary conditions and calculate aerodynamic performances. The results showed that the new airfoil has a higher lift coefficient and lift-to-drag ratio in on-design and off-design operation conditions and at the main range of attack angles. This multidisciplinary design integrates well parametric representation and CFD simulation， which can also provide a reference for similar aerodynamic optimization designs. References | Related Articles | Metrics

Select

Reliability of Dust Explosion Venting Standards Under Elevated Static Activation Overpressures YU Jian-liang， YAN Xing-qing 2015, 36 (9):  1316-1320.  DOI: 10.3969/j.issn.1005-3026.2015.09.022 Abstract ( 596 )   HTML   PDF (822KB) ( 724 )   The reliability of dust explosion venting standards is of great importance to explosion protection. Dust explosion venting experiments with four venting diameters under elevated static activation overpressures ranging from 0.12 to 0.6MPa were performed in the 20-liter chamber. The lycopodium dusts with a median diameter of 70μm were adopted. The experimental results were compared with the predictive values calculated by NFPA 68 and EN 14491. The results indicated that NFPA 68 results tend to be conservative for small venting diameters and dangerous for larger venting diameters. It was found that the prediction results of NFPA 68 correlation have a good accuracy and are stable under elevated static activation overpressures. However， the prediction results of EN 14491 are inaccurate and unstable， which tend to be very conservative. The huge divergence between NFPA 68 and EN 14491 results under elevated static overpressures was analyzed based on the correlations of the empirical functions proposed by the standards. References | Related Articles | Metrics

Select

Fatigue Life Prediction of Large-Span Samples Based on the Optimized SVR Model YANG Da-lian， LIU Yi-lun， ZHOU Wei， YI Jiu-huo 2015, 36 (9):  1321-1326.  DOI: 10.3969/j.issn.1005-3026.2015.09.023 Abstract ( 544 )   HTML   PDF (512KB) ( 673 )   Aiming at the issue that the prediction accuracy of fatigue life is not high by the traditional methods with large-span and small samples， a new life prediction method based on the optimized SVR model was studied. Considering the traits of large-span samples， the effective sample pretreatment method， the training method for the SVR model and the criterion for parameter optimization were put forward. Taking the life prediction of LY12CZ (2A12) aluminum alloy for example， the effects of the kernel functions of Gauss， polynomial and multilayer perception on the training error of the SVR model were analyzed. The results showed that the Gaussian kernel function is more suitable for SVR model training and the kernel function parameter γ and the penalty factor C can be optimized by the bacterial foraging algorithm. Thus， the life prediction results verify the validity of this method. References | Related Articles | Metrics

Select

Asymmetric Analysis of Pressure Distribution in the Gear Pump’s Master-Slave Gear Cavity LIU Wei， WANG An-lin， SHAN Xue-wen， ZHANG Xiao-lu 2015, 36 (9):  1327-1331.  DOI: 10.3969/j.issn.1005-3026.2015.09.024 Abstract ( 575 )   HTML   PDF (622KB) ( 659 )   Based on the distribution features of a gear pump’s flow field， the asymmetric pressure distribution in the master-slave gear cavity was analyzed. Taking a certain type high-pressure gear pump as the research object， the relationship between the radial clearance and the deflection of gear shaft was analyzed. The nonlinear differential equation of pressure in the transition zone was established. Comparing the corresponding position pressures of both master and slave gear side cavities， it could be concluded that the pressure distribution of a gear pump’s master-slave gear cavity is asymmetric. The experimental data showed that the corresponding point pressure value between the experimental and theoretical error is less than 5.0%. The master and slave pressure difference is 4.17MPa in the transition zone， and the pressure difference is 1.55MPa at the end of high-pressure groove under the rated conditions. This study provides a theoretical basis on the asymmetric analysis of pressure distribution in the high-pressure gear pump’s gear cavity and on the calculation of floating end plates’ overturning torque. References | Related Articles | Metrics

Select

Customers’ Perceptual Cognition of the Visual Comfort of Automobile Seats SUN Lin-lin， KONG Fan-sen， LIU Wei 2015, 36 (9):  1331-1336.  DOI: 10.3969/j.issn.1005-3026.2015.09.025 Abstract ( 550 )   HTML   PDF (860KB) ( 816 )   Customers’ first perceptual cognition of automobile seats impacts their evaluation and preference for the whole car. Eye tracker was used to test specific consumer groups’ visual perception of automobile seats in different fixation times and with different car types， whose results indicated that the backrest and neck attracted the participants’ attention most when they were visually stimulated by the seat in a short time. With the increase of fixation time， the participants tended to compare perceptual elements as such seat design， color， shape and material. Attention to a certain semantic form of the seat gradually developed into the combination of semantic transfer and emotions when the participants spent a long time choosing from various seats. Despite the discussion on customers’ real inner needs， there are still many uncertain facts in the experiments， which will be refined in the future research. References | Related Articles | Metrics

Resources & Civil Engineering

Select

Mesh Sensitivity Analysis of the Solution to Hydraulic Fracture Problems Based on a Smeared Crack Model LI Ming， LIANG Li， GUO Pei-jun， LI Xin 2015, 36 (9):  1337-1341.  DOI: 10.3969/j.issn.1005-3026.2015.09.026 Abstract ( 1228 )   HTML   PDF (646KB) ( 784 )   Mesh quality is an important factor that affects the simulation results in nonlinear soil/rock mechanic problems. The effect of aspect ratio of element (AR) on calculation was analyzed in numerical solution of hydraulic fracture for the smeared crack model. Elasticity was measured by adopting the porous elastic (PE) and linear elastic (LE) constitutive models. Regarding to material yielding and failure， both the Drucker-Prager (DP) and Mohr-Coulomb (MC) models were considered. Based on a comprehensive analysis， it is concluded that no matter which constitutive model is adopted， there always exists mesh sensitivity. If the direction of fracture propagation is known， the AR should be between 2.8 and 8.0 to obtain stable results. If the direction is unknown， it is recommended that the LE constitutive model as well as the MC/DP plasticity model should be used together with the AR equal to 1.0. References | Related Articles | Metrics

Select

Experimental Research of the Ignition of Converter Gases by Hot Particles SHANG Rong-xue， LI Gang， YU Li-fu， DONG Mao-lin 2015, 36 (9):  1342-1346.  DOI: 10.3969/j.issn.1005-3026.2015.09.027 Abstract ( 590 )   HTML   PDF (586KB) ( 626 )   In order to analyze the explosion risk of converter gases in the process of reclaiming， a set of test devices for converter gas ignition by iron oxide particles heated radiatively was set up. The rules of mixture ignition at varied initial temperatures and with particle diameters were investigated， based on the explosion pressure and temperature changes of converter gases/air mixtures. The results showed that when the particle diameters are constant， the sensitive concentrations of converter gases/air mixtures increase by 5% if the initial temperature changes from 100℃ to 35℃. The ignition temperatures of 1.5mm-diameter particles drop by 137.6， 145 and 134.5℃ compared to the 0.5mm-diamete particles when the initial temperature is 35， 100 and 200℃ respectively. When the particle diameters are 0.5mm， 1.0mm and 1.5mm separately， the ignition temperatures decrease by 19.8， 11.6 and 16.7℃ with the initial temperature changing from 200℃ to 35℃. The research findings can provide a reference for limiting hot particle diameters before high temperature converter gases enter heat exchangers. References | Related Articles | Metrics

Select

Acoustic Emission Characteristics During Short-Time Creep Process of Red Sandstone Under Different Stress Level GONG Cong， LI Chang-hong， ZHAO Kui 2015, 36 (9):  1347-1352.  DOI: 10.3969/j.issn.1005-3026.2015.09.028 Abstract ( 530 )   HTML   PDF (1566KB) ( 644 )   The characteristics of acoustic emission (AE) of the red sandstone during short-time creep were studied under different stress level. The results show that the AE event ratios and energy ratios decrease with time increase during the period from decelerated creep to steady creep， and the corresponding reductions in amplitude decrease with the increasing stress level. The AE amplitude decreases and keeps relatively stable when the stress is about 40%~60% and 70%~80% of peak stress， respectively. The AE amplitude transition frequency increases obviously during the accelerated creep stage， and its event ratio and energy ratio begin to increase in the mid-late stage of accelerated creep. Therefore， the creep stage of red sandstone can be distinguished by the AE characteristics. References | Related Articles | Metrics

Select

Heating Technology and Heat Transfer Simulation for Oil Shale of In-situ Pyrolysis by Fracturing and Nitrogen Injection JIANG Peng-fei， SUN You-hong， GUO Wei， LI Qiang 2015, 36 (9):  1353-1358.  DOI: 10.3969/j.issn.1005-3026.2015.09.029 Abstract ( 558 )   HTML   PDF (784KB) ( 776 )   A new method for the in-situ conversion of oil shale was introduced i.e.， oil shale in-situ pyrolysis technique by fracturing and nitrogen injection. Electrical heater was put into the heating well and nitrogen was then pumped into the well. As a result， the oil shale layer was pyrolyzed by heated nitrogen. The advantages of the proposed method and the suitable layers were also introduced in comparison with traditional electrical heating and convective heating， and a computer simulation was done for the heating process of nitrogen. The parameters of the heater were optimized and it was confirmed that the length of the electrical heater was 30m and the heat flux was 11kW/m2. Finally， based on the suitable thin oil shale layers， it was verified by the computer simulation that the heating time is 80days under the condition that the distance of the heating well and the production well is 15m while the thickness of the oil shale layer is 1.5m. Obviously， the time is shortened compared with traditional electrical heating or convective heating. References | Related Articles | Metrics

Management Science

Select

Wholesale Price Contract and Coordination Considering Fuzzy Demand and Inequity Aversion WANG Ning-ning， WANG Xiao-huan， FAN Zhi-ping 2015, 36 (9):  1358-1362.  DOI: 10.3969/j.issn.1005-3026.2015.09.030 Abstract ( 549 )   HTML   PDF (465KB) ( 666 )   For the problem of wholesale price contract and coordination under fuzzy demand， a wholesale price contract model considering retailer′s inequity aversion was constructed based on the inequity aversion model proposed by Fehr and Schmidt. Then， the impacts of retailer′s inequity aversion on order quantity and supply chain profit were analyzed through model reasoning and numerical experiment. The results showed that retailer′s optimal order quantity and supply chain profit will decrease as retailer′s disadvantageous inequity aversion increases. Retailer′s order quantity and supplier′s profit will increase， and retailer′s profit as well as the total profit of whole supply chain will first increase and then decrease， as retailer′s advantageous inequity aversion increases. In addition， wholesale price contract can coordinate supply chain under certain conditions. References | Related Articles | Metrics

Select

Effects of Senior Executives’ Overconfidence on Transnational M&A Performance——An Empirical Research Based on China’s Listed Companies ZHANG Lan-xia， JIA Ming-mei ， XUE Bi-yun， ZHANG Liang-ting 2015, 36 (9):  1363-1368.  DOI: 10.3969/j.issn.1005-3026.2015.09.031 Abstract ( 506 )   HTML   PDF (337KB) ( 719 )   To understand objectively the transnational merger and acquisition (M&A) of Chinese companies during the post-financial crisis period， and provide a useful reference for future transnational M&A decisions， senior executives’ overconfidence was examined by applying the shareholding change method and using the data samples from the listed companies in Shanghai and Shenzhen exchange markets that carried out transnational M&A during 2008-2010. Then the assessment indexes of transnational M&A performance were formulated with factor analysis， and the impacts of senior executives’ overconfidence on transnational M&A performance were explored with descriptive statistical analysis， simple correlation analysis and partial correlation analysis. The results showed that the senior executives’ overconfidence in China’s listed companies has a positively significant correlationship with the performance of the year before transnational M&A and a negatively significant correlationship with the performance of the year after. Moreover， it is negatively correlated to the performance of the year and the two years after transnational M&A， but its significance varies with different research data and methods. References | Related Articles | Metrics