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Table of Content

    25 June 2016, Volume 44 Issue 6
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    Chemistry & Chemical Engineering
    Color Masking and Mechanical Properties of Lignin/High-Density Polyethylene Composites
    QIU Xue-qing CHEN Jian-hao CAI Zhen-he ZHOU Ming-song
    2016, 44(6):  1-8.  doi:10.3969/j.issn.1000-565X.2016.06.001
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    In this paper,the influence of different colorants on the color masking properties of lignin/HDPE (High- Density Polyethylene) composites was investigated,finding that the black color of lignin/HDPE composites can be effectively masked after the addition of iron oxide and that red composites with poor mechanical properties can be obtained.Then,different plastic additives were used to prepare red composites with improved mechanical proper- ties,and an elongation at break of 102. 43% was reached with the addition of 1 phr aluminium stearate,which is two times that of the composites without aluminium stearate.Melt index test results show that the molten red com- posites are of good flowing properties.Thermo-oxidative aging test results indicate that the red composites possess good thermal decomposition resistance.Rheological investigation reveals that the prepared red composites are pseu- do-plastic,with an apparent viscosity decreasing with the addition of aluminium stearate.And,SEM observation shows that lignin and iron oxide particles are homogeneously mixed in the HDPE phase.
    Preparation and Battery Performance of Spherical LiFePO4 /C Doped with Mg2+
    YANG Wei XUE Jian-jun CHEN Sheng-zhou HU Xin-fa XIA Xin-de LIN Wei-ming
    2016, 44(6):  9-13.  doi:10.3969/j.issn.1000-565X.2016.06.002
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    Spherical LiFePO4 /C  doped with Mg2+ (namely LiMgx Fe1－x PO4 /C) was prepared by means of the spray drying-carbonthermal reduction,with citric acid,ferrous oxalate and magnesium acetate as the carbon source,the iron source and the magnesium source,respectively.Then,the effects of Mg2+ doping on the structure and electrochemical performance of the prepared LiFePO4 /C material were investigated.The results indicate that (1) LiMgx Fe1－x PO4 /C possesses a hollow ball-shaped structure and a high specific capacity; (2) the crystal struc- ture of lithium iron phosphate keeps unchanged at a low Mg2+ dosage; and (3) LiMg0.04 Fe0.96 PO4 /C possesses the best charge/discharge performance.For instance，its initial discharge capacities are 149. 0,145. 6,141. 3,132. 6 and 123. 3mAh/g at the rates of 0. 2C,0. 5C，1. 0C,2. 0C and 5. 0 C,respectively; and the capacity retention ra- tio of LiMg0.04 Fe0.96 PO4 /C at 1. 0C keeps more than 97. 3% after 100 charge-discharge cycles.
    Investigation into Selective Separation of Lignin in Novel Deep Eutectic Solvent
    CHANG Jie LIU Jun GUO Shu-jun WANG Xi FU Yan
    2016, 44(6):  14-20,26.  doi:10.3969/j.issn.1000-565X.2016.06.003
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    In recent years,choline,a novel kind of bio-based ILs (Ionic Liquids) used as a good lignin solvent,has been paid more and more attention to.In this paper,based on Hansen's theory of solubility,a novel ionic liquid analogue named DES (Deep Eutectic Solvent),in which lactic acid (LA) and choline chloride (ChCl) were respectively used as the donor and the acceptor of hydrogen bonds,was designed to separate lignin.Then,the dissolution results of lignin affected by the molar ratio of ChCl to LA,the reaction temperature and the interaction time were investigated by experiments.It was found that the dissolution rate of lignin reached the optimal 90. 1% and the purity of regenerated lignin reached 96. 3% at a ChCl-to-LA molar ratio of 1∶ 9,a reaction temperature 90℃ and a reaction duration of 12 h.The results of UV-Vis spectroscopy and FT-IR spectroscopy show that the lignin in the wood powders is greatly removed after DES treatment.XRD results show that the structure of cellulose in the pretreated wood powders is barely damaged.13C NMR results indicate that the regenerated lignin is mainly composed of syringyl,guaiacyl and a little p-hydroxylphengl.Moreover,ion chromatography results show that only a small amount of holocellulose is dissolved in the mixed solution.
    Reduction of Harmful Components in Cigarette Smoke via Delignification of Tobacco Stem by Means of Oxygen Alkali Technology
    YI Cong-hua ZHANG Su-wen JI Wei-ni KONG Hao-hui ZHOU Rong
    2016, 44(6):  21-26.  doi:10.3969/j.issn.1000-565X.2016.06.004
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    Tobacco stem was delignified by means of the oxygen alkali technology and was then used to produce to- bacco sheets.The variations of harmful components in the cigarette smoke were investigated,and the optimal condi- tions of oxygen alkali technology were determined as follows: a liquid-solid ratio of alkali liquor to tobacco stem of 10mL/g,a mass ratio of potassium hydroxide to tobacco stem of 35%,a reaction temperature of 120℃,a reaction time of 40min,an oxygen pressure of 0. 6MPa and a dosage of protective agent MgCO3 of 0. 5%.It is found that,as compared with the traditional water soaking pretreatment,the pretreatment with oxygen alkaline is more effective because it helps to reduce the contents of lignin,phenol,pyrocatechol and the total harmful substance by 47. 9%,61%,25% and 38%,respectively.
    reparation and Catalysis Performance of Hemicelluloses-g- Chitosan-Pd(0) Catalyst
    PENG Xin-wen TAN Jie-wen WU Chang-yan DENG Qing LIN Jia-chun SUN Run-cang
    2016, 44(6):  27-34,40.  doi:10.3969/j.issn.1000-565X.2016.06.005
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    Hemicelluloses-g-chitosan was prepared via click reaction under mild conditions and was used as a sup- porter to produce hemicelluloses-g-chitosan-palladium(0) catalyst through a simple reduction reaction.Then,the catalyst was characterized by means of FT-IR,TGA,SEM,XRD and XPS,with high catalytic activity for Suzuki coupling being revealed.Moreover,the yields of Suzuki reaction affected by the solvent type,the catalyst dosage,the reaction temperature,the base,the substrate and the recycle number were investigated.The results show that the yield is up to 84% after a reaction at 70℃ for 3h by using ethanol as the solvent and K2CO3 as the base; and that the catalyst can be recycled through a simple method and be reused at least five times,with a yield decreasing to 61. 6%.
    Variations of Fiber Morphology and Papermaking Performance of Tobacco Stem After Extraction with Alkaline Ionic Liquid
    HOU Yi LIU Chao LI You-ming LUO Guan-rong HU Song-qing
    2016, 44(6):  35-40.  doi:10.3969/j.issn.1000-565X.2016.06.006
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    This paper deals with the fiber morphology,beating performance and papermaking performance of tobacco stem (a kind of reconstituted tobacco raw material) after the extraction with alkaline ionic liquid［MMIM］DMP by means of IR and component analysis.The results show that (1) after the extraction with ［MMIM］DMP,a small amount of honeycomb structure may occur in the epidermal tissue of tobacco stalk,and the filler among fiber cells decreases significantly,while the porosity increases; (2) as the aromatic substances and lignin in tobacco stems dissolve well in the alkaline ionic liquid,the relative content of cellulose in the raw material remarkably increases; and (3) the tobacco stem after partial delignification is of uniform fiber dispersion,good beating and papermaking performances,high tensile strength (with an increment of 35%) as well as optimized bulk and porosity parameters.
    Effect of Magnesium Ion on Oxidation Activity of Acidthiobacillus ferrooxidans
    XU Xiao-fang LIN Hai DONG Ying-bo ZHOU Shan-shan
    2016, 44(6):  41-46.  doi:10.3969/j.issn.1000-565X.2016.06.007
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    By taking acidophilic bioleaching bacteria (Acidthiobacillus ferrooxidans,At. f for short) as the research objective,this paper discusses the effect of Mg2+ on the oxidation activity of At. f and analyzes the corresponding in- ternal mechanism by means of Zeta potential and infrared spectroscopy.The results indicate that,when the mass concentration of Mg2+ is less than 5. 0g/L,after a cultivation for 35h,the pH value of the system decreases from 2. 00 to 1. 70,the oxidation reduction potential increases from 390mV to more than 600mV,the Fe2+ oxidation rate is up to 100%,and the bacteria are in an exuberant growth period; and that,when the mass concentration of Mg2+ is more than 5. 0g/L,the reduction rate of pH value,the rise rate of the oxidation reduction potential,the oxida- tion rate of Fe2+ and the bacteria growth rate all decrease,and the decreasing rate is positive to the mass concentra- tion of Mg2+ .Zeta potential tests show that the bacteria isoelectric point is 3. 6 under the action of 20. 0g/L magne- sium ions,which is higher than that of the bacteria cultivated in 9K medium,namely 2. 7.This is the macroscopic cause of the structure variation of bacterial cell walls.Moreover,IR results show that,under the action of magne- sium ions,the functional groups of the bacterial cell walls crosslink,which results in the disappearance of N—H absorption peak as well as the migration of —OH，—C＝O，—CH3 ,—CH2 ,—P＝O and —CN.Thus,the structure of the cell surface protein changes and the oxidation activity of bacteria decreases.
    Materials Science & Technology
    Phase Change of Steel Slag During Reconstruction by Lime
    YIN Su-hong GAO Fan GUO Hui YANG Xu
    2016, 44(6):  47-52.  doi:10.3969/j.issn.1000-565X.2016.06.008
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    Steel slag was reconstructed by using lime as the single controlling material at a high temperature,and XRD,petrographic analysis and SEM techniques were adopted to determine the mineral composition of the modified steel slag as well as the transformation of the RO phase in the modification process.Moreover,the stability and the activity index of the modified steel slag were tested.The results demonstrate that (1) the RO phase primarily reacts with CaO,in which FeO phase is decomposed into Fe3O4 ,CF (calcium ferrite),C2F (dicalcium ferrite), Ca2 (AlFe)O5 and C4 AF (tetracalcium alumino-ferrite) successively with the increase of CaO content,and a part of MgO phase exists in the form of MgO crystal,and the others behave as the solid solution in the silicate and liquid phases; (2) when the CaO/SiO2 mole ratio is not large enough,C3 S (tricalcium silicate) in the original steel slag is resolved into C2 S (dicalcium silicate) in the modification process; (3) no C3 S generates even when the CaO/SiO2 mole ratio reaches 3 because CaO primarily reacts with high-content iron; (4) only when the iron reacts completely,may the redundant CaO react with C2 S to produce C3 S; and (5) both the stability and the cementitious activity of the steel slag significantly improve after the modification by lime.
    Effect of Calcium Sulfate on Early Hydration of Calcium Aluminate Cement-Based Blends
    XU Ling-lin WANG Pei-ming YANG Xiao-jie Horst-Michael LUDWIG
    2016, 44(6):  53-58.  doi:10.3969/j.issn.1000-565X.2016.06.009
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    This paper deals with the heat release and paste microstructure during the early hydration of calcium alu- minate cement-Portland cement-calcium sulfate (anhydrite or α-hemihydrate) blends by means of calorimetry,X- ray diffraction,environmental scanning electronic microscopy and mercury intrusion porosimetry.The results show that (1) when calcium sulfate is blended with the binder,the early hydration accelerates and is dominated by the formation of ettringite as well as the corresponding transition into hydrated mono-sulphate; (2) in the first 30 mi- nutes of hydration,short and coarse ettringite in a length of about 1μm forms in the matrix,which leads to the oc- currence of the first heat evolution peak; (3) in the following 8 hours,another two obvious heat evolution peaks occur,one resulting from the dissolution of calcium aluminates and anhydrite as well as the formation of etttingite in the paste with anhydrite,the other resulting from the growth of etttingite and the formation of mono-sulphate; (4) for the paste with α-hemihydrate,both of these two peaks are attributed to the formation and growth of etttingite; and (5) thanks to its rapider dissolution than anhydrite,α-hemihydrate matches well with the dissolution of calcium aluminate,so that the paste with α-hemihydrate contains more ettringite and exhibits lower porosity.
    Fuzzy Comprehensive Quality Evaluation of Chopped Carbon Fiber Based on Entropy Weight
    LIU Xiao-kang YANG Feng GAO Jiao LU Long-sheng
    2016, 44(6):  59-64.  doi:10.3969/j.issn.1000-565X.2016.06.010
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    In order to overcome the instability and control difficulty of the chopping process of carbon fibers (CFs),the process parameters affecting the quality of chopped CFs were investigated.By taking the oven tempera- ture,the press roll pressure,the cutter roll pressure and the chopping speed as the evaluation factors and by using the length dispersion,the width uniformity,the fracture section uniformity and the fracture surface morphology as the quality evaluation indexes,some orthogonal experiments were designed and carried out,from which the evalua- tion weight of each quality evaluation index was determined based on the entropy theory.Moreover,the chopping process parameters were evaluated via a fuzzy comprehensive evaluation.The results show that the CFs with the best quality can be chopped at an oven temperature of 150℃,a press roll pressure of 0. 2MPa,a cutter roll pressure of 0. 4MPa and a chopping speed 6. 9m/min.
    Breakup Process and Force Chain Evolution of Particle Aggregates in Flow Field
    MA Xiang-jun WU Zhe-hao
    2016, 44(6):  65-69,76.  doi:10.3969/j.issn.1000-565X.2016.06.011
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    The dispersion effect of particle aggregates has a direct impact on the comprehensive properties of com- posite materials.In order to reveal the dispersion mechanism and dynamic details of particle aggregates,a 3D dis- crete element program,Demix3D,which involves the van der Waals force among particulates,is developed to nu- merically simulate the deformation and dispersion process of aggregates in a simple shear flow field,and to further explore the mesostructure evolution of the aggregates in the dispersion process.The results show that complex force chain network caused by the interwining of strong and weak force chains form in the aggregates.In this network,the strong force chains mainly distribute in the interior and transfer the majority of the force from the flow field,while the weak force chains fully distribute in the network and transfer the minority of the force.Moreover,it is found that the dispersion mode of the particles is directly determined by the evolution of the force chain network,and that the fragments no longer disperse due to the close contact among the particles with strong force chains when the dispersion of the particles reaches its equilibrium.In addition,the effect of flow field intensity on the dispersion of the aggregates is analyzed according to the weighted average particle number of the fragments.
    Effect of Rolling Deformation on Quench Sensitivity to Exfoliation Corrosion of Thick Al-5Zn-3Mg-1Cu-0. 12Zr Alloy Plate
    LI Dong-feng ZHANG Xin-ming YIN Bang-wen LIU Sheng-dan LEI Yue DENG Yun-lai
    2016, 44(6):  70-76.  doi:10.3969/j.issn.1000-565X.2016.06.012
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    This paper deals with the effect of rolling deformation on the quench sensitivity to the exfoliation corro- sion (EXCO) of thick Al-5Zn-3Mg-1Cu-0. 12Zr alloy plates by means of end-quenching testing,corrosion immer- sion testing,optical microscopy and transmission electron microscopy.The results show that (1) the resistance to EXCO of the plate decreases with the decrease in cooling rate,and the decrement of EXCO resistance increases with the increase in hot rolling deformation,which means that there exists an increasing quench sensitivity to EX- CO; (2) when the rolling deformation ranges from 56% to 91%,the exfoliation corrosion levels of all the samples are P at a quench rate of 2160℃ /min,while the level varies from EA to ED at a quench rate of 100℃ /min; (3) when the rolling deformation is 56%,72%,81% and 91%,the exfoliation corrosion level is EA or deeper than EA at the quench rates of more than 100,159,209 and 320 ℃ /min; and (4) under a constant rolling deforma- tion,the precipitate free zone will be widened with the decrease of quench rate,which may result in the degrada- tion of the exfoliation corrosion resistance.
    Environmental Science & Technology
    Investigation into Synergic Enhancement Disinfection of Drinking Water in Ultrasonic Field
    ZOU Hua-sheng Lü Xue-ying
    2016, 44(6):  77-82.  doi:10.3969/j.issn.1000-565X.2016.06.013
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    The traditional chlorine disinfection can not effectively disinfect polluted water and may result in exces- sive residual chlorine.In order to solve this problem,ultrasonic field was used to enhance the chlorine disinfection of E. coli in drinking water,and the corresponding laws and features were investigated.Moreover,the optimal con- ditions for the synergy disinfection were determined.Experimental results indicate that (1) for the water with an initial E. coli density of about 104 CFU/mL,a treatment with 59kHz and 90W ultrasonic for 5min at the room tem- perature may result in an E. coli logarithmic inactivation rate of 0. 9; (2) after a treatment in sodium hypochlorite solution with an active chlorine content of 9. 0mg/L for 30min,the logarithmic inactivation rate increases to 2. 57; (3) the synergic disinfection with the two above-mentioned treatment methods helps to obtain a logarithmic inacti- vation rate of 5. 02 and a residual chlorine content of less than 4mg/L,which meets the national standard well.
    Experimental Investigation into Degradation of 2,4-Di-Tert-Butyl-Phenol Catalyzed by Zero Valent Iron
    GAO Nai-yun LIU Xue-fei ZHOU Gong-ming WANG Qiong-fang
    2016, 44(6):  83-89,97.  doi:10.3969/j.issn.1000-565X.2016.06.014
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    Zero valent iron (Fe0 ) was used to activate persulfate (PS) to generate SO－4 · and thus to oxidize the 2,4-di-tert-butyl-phenol (DTBP) in water.Then,the degradation of DTBP at various initial Fe0 dosage,initial PS concentration,initial pH value and temperature was investigated,and the effects of ultra violet light (UV),Fe0 and Fe2+ on the degradation were analyzed in a comparative way.The results indicate that (1) the degradation of DTBP accelerates when the Fe0 dosage increases from 0. 5 to 4. 0mmol/L,while an inhibition may occur when the dosage reaches 5. 0 mmol/L; (2) the increase in PS concentration from 0. 125 to 0. 500mmol/L in DTBP solution can accelerate the degradation of DTBP,but the degradation velocity firstly decreases and then increases when the PS concentration continuously increases; (3) the velocity of Fe0 -catalyzed degradation for DTBP gradually decreases with the increase of the initial pH value; (4) temperature has no obvious effect on the activation of PS in degrading the DTBP in a heat-activated PS system,and only 42% of DTBP is degraded within 60 min at 55 ℃; (5) when the temperature increases from 35 to 45 ℃,the degradation velocity of DTBP decreases slightly in both the heat- activated PS and the Fe 0 /PS systems; and (6) as compared with UV and Fe2+ ,Fe 0 performs a consistent catalytic degradation effect on DTBP,and helps to achieve the highest degradation efficiency of 98% within 60 min,also， the Fe0 -activated degradation is more economical and environmentally friendly.
    Effect and Kinetics Analysis of Eugenol Degradation by Ozone
    LI You-ming CHEN Jing-tian LEI Li-rong
    2016, 44(6):  90-97.  doi:10.3969/j.issn.1000-565X.2016.06.015
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    Ozone was employed to degrade the water-soluble lignin-derived compound eugenol in a simulated wastewater system,and the effects of pH value,initial eugenol concentration,ozone mass concentration and reac- tion temperature on the CODCr removal as well as the corresponding kinetics were investigated.Experimental results show that (1) the ozonation process is effective in degrading eugenol; (2) the CODCr removal is up to 67. 77% after the ozonation with an initial eugenol concentration of 1 mmol/L and with an ozone mass concentration of 24. 83mg/L at 25℃ and pH 11; (3) the CODCr removal of eugenol accords well with the two-stage pseudo-first- order kinetics; and (4) the exponential function is effective in analyzing the ozonation kinetics and obtaining the kinetic models describing the CODCr removal within 0 ～10min and 10 ～60min，respectively.
    Traffic & Transportation Engineering
    Parameterized Analysis and Optimization of Vehicle Anti-Roll Bar
    SHI Bai-jun LIU De-hui LI Zhen-yan
    2016, 44(6):  98-104,112.  doi:10.3969/j.issn.1000-565X.2016.06.016
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    In this paper,first,a geometry parameterization of the anti-roll bar is performed.Next,the formulas of the rolling angle stiffness are deduced by means of the Moore integral method,followed by a preliminary strength verification.Then,a finite element simulation is carried out to verify the feasibility of the proposed method.Mo- reover,an optimization design of the anti-roll bar of a SUV is conducted via the proportionality coefficient method,with the rolling angle stiffness as the optimization objective.Finally,a simulation model is established in ADAMS/ Car to verify the effectiveness of the optimization through a steering wheel step input test，followed by a real car ex- periment.The results of both the simulation and the real car experiment show that good roll stability can be ob- tained at a high rolling angle stiffness of the anti-roll bar.It is thus concluded that the proposed optimization method is feasible.
    Mechanical Behavior Characteristics of Asphalt Plug Expansion Joint Pavement's Interface
    XIAO Min-min
    2016, 44(6):  105-112.  doi:10.3969/j.issn.1000-565X.2016.06.017
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    In APEJ (Asphalt Plug Expansion Joint) pavement,the interface is the weakest link in the whole structure.In this paper,the material parameters of each part of the expansion joint were determined,and,by se- lecting the maximum axle load (140 kN) of road-grade I as the calculating load,a finite element model of the pavement was established with ANSYS.Then,the interfacial indexes were calculated under 4 kinds of loads,and the corresponding interfacial controlling indexes were extracted.Finally,the effects of expansion joint mixture's modulus,interfacial friction coefficient,interfacial elevation difference,horizontal force and tire contact pressure on the interfacial controlling indexes were analyzed.The results show that (1) the interfacial controlling indexes include the tensile stress,the shear stress and the interfacial vertical displacement; (2) both the horizontal force and the tire contact pressure have a great influence on the interfacial tensile stress and shear stress,while the mo- dulus ratio,the horizontal force,the tire contact pressure exert a great influence on the vertical displacement of the interface; (3) such measures as choosing expansion joint mixture with great modulus,coarsing the interface，set- ting small interfacial elevation difference，preventing urgent starting or braking on the expansion pavement and avoiding overload are all effective in preventing the interface from damage.

    Analysis of Drainage Characteristics Based on Microstructure of Porous Asphalt Mixture
    XIAO Xin ZHANG Xiao-ning
    2016, 44(6):  113-120.  doi:10.3969/j.issn.1000-565X.2016.06.018
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    In this paper,the influences of connecting air voids on the seepage characteristics of the porous asphalt mixture were investigated; the micro-distribution characteristics of the porous asphalt mixture is discussed based on industrial CT; a seepage-flow numerical model of the mixture is established; the internal flow characteristics of wa- ter within the porous asphalt mixture is analyzed by using the finite volume method; and the water flow characteris- tics affected by the diameter,the tortuosity and the minimum sectional size of the connecting air voids are dis- cussed.The results indicate that (1) the air void diameter greatly influences the flow velocity and the velocity is approximately proportional to the square of the void diameter; (2) the larger the tortuosity is,the smaller the ve- locity and the flow are; (3) as the bending structure has little influence on the velocity and the flow,it can be neglected and the tortuosity is solely taken into consideration; (4) if the minimum sectional diameter of the con- necting air voids is taken as the equivalent diameter of the whole water path for analyzing the seepage characteri- stics,the calculated permeability coefficient may be smaller than the actual value,so that a revision is necessary.
    Reliability Back Analysis of Shear Strength Parameters of Landslide Considering Mutual-Correlation Between Parameters
    ZHAO Lian-heng ZUO Shi CHEN Jing-yu WANG Zhi-bin
    2016, 44(6):  121-128.  doi:10.3969/j.issn.1000-565X.2016.06.019
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    As the traditional deterministic back analysis methods fail to consider the influence of randomness and uncertainty of geotechnical parameters on the slope stability,a new parameter back analysis method with simplicity and practicality,which combines the upper bound method of limit analysis with the reliability theory,is proposed.Then,the feasibility and effectiveness of the proposed method are verified through an engineering application case.The results show that the proposed method not only takes into account the uncertainties and instability of the geotechnical parameters but also helps to implement the back calculation of the shear strength parameters of a slid- ing surface.Meanwhile,the effects of the correlation of shear strength parameters on the back analysis results and the reliability are analyzed,finding that ignoring the mutual-correlation between parameters may lead to a conserva- tive reliability index.
    Traffic & Transportation Engineering
    Characteristics of Smoke in Tunnel with On-Fire Train Moving in Subway Tunnel
    XI Yan-hong MAO Jun BAI Guang HU Jia-wei
    2016, 44(6):  129-136.  doi:10.3969/j.issn.1000-565X.2016.06.020
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    Ensuring the safety of the on-fire train moving in a subway tunnel is the goal of the corresponding emer- gency rescue.In this paper,with the help of STAR-CCM + possessing the function of mesh sliding,CFD (Com- putational Fluid Dynamics) simulations are carried out to investigate the effects of train speed and heat release rate on the smoke characteristics in a tunnel,and the distribution of smoke temperature as well as the optimal speed of the on-fire train traveling in the tunnel are explored.The results show that (1) for the on-fire train moving in a subway tunnel，there is an optimal speed corresponding to the lowest temperature,namely 50 km/h; (2) when the train moves at a constant speed,the temperature peak at the typical eye points increases with the heat release rate; (3) at a constant heat release rate,the maximum temperature first decreases and then increases with the train speed,presenting an upward parabola; (4) the temperature at the train roof inlet gradually increases when the on-fire train moves forward in the tunnel,and the maximum temperature is of a large oscillation on the neutral surface; (5) the minimum temperature (166. 45 ℃) occurs at 340 m in the tunnel; and (6) the train might be burnt due to the high temperature at the train top,so that a ventilation measure should be adopted to reduce the temperature of the annular tunnel space when a subway train is on fire.
    Influence of Adjacent Bridges on Interaction System of Large-Span Steel Truss Girder and Railway
    YU Xiang-dong YIN Xing-quan YAN Bin
    2016, 44(6):  137-142,148.  doi:10.3969/j.issn.1000-565X.2016.06.021
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    By taking a 156m large-span simply-supported steel truss girder on the Huangling-Hancheng-Houma line as a case,the influence of adjacent bridges on the longitudinal force distribution in the continuously-welded rail (CWR) on the steel truss girder is analyzed,and some suggestions are presented for the selection of relevant pa- rameters.In the investigation,nonlinear spring is used to simulate the longitudinal resistance of CWR and the beam element with rigid arms is employed to simulate the steel truss bridge.Calculation results show that (1) when the longitudinal stiffness of the substructure has no obvious variation,the multi-span simply-supported beams at both sides of the steel truss girder can be simplified into a girder with 6 spans for analyzing the longitudinal force; (2) as compared with the standard span of 32m for simply-supported beams,a span of 24 m may result in a force de- crease at the fixed end by 9%,while a span of 40m may result in a force increase by 7%; (3) by taking the adja- cent large-span continuous beam into consideration,the longitudinal force at the fixed end of the steel truss girder increases by 2. 2 times and the maximum compressive stress of the full bridge increases by 12%; (4) the longitudi- nal force at the fixed end of the steel truss girder is significantly reduced when simply-supported beams with one or two spans are arranged between the continuous beam and the steel truss girder; and (5) fasteners with small resis- tance helps to reduce the maximum stress and the horizontal force loaded on the pier.
    Integral Weighted Evaluation Method for Custom-Made Type Selection of Hydraulic Torque Converters
    WANG An-lin MENG Qing-hua LI Wen-jia ZHANG Ming-quan
    2016, 44(6):  143-148.  doi:10.3969/j.issn.1000-565X.2016.06.022
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    In order to implement the dynamics matching between the working condition characteristics of vehicles and the type selection of hydraulic torque converters,an integral weighted evaluation method (IWEM) for the cus- tom-made type selection of torque converters is proposed.In this method,on the basis of the load characteristics of the vehicle,the speed ratio interval-efficiency weights of the torque converter are set correspondingly,the efficien- cy characteristic curve is segmented and integrated,and the corresponding integral weighted evaluation value is calculated and used as the evaluation standard of the economic performance of torque converters.Then,two exist- ing torque converter models are used as the objects to verify the effectiveness of the proposed IWEM for the custom- made type selection of torque converters.The results indicate that IWEM helps to set up the dynamic mapping rela- tionship between the vehicle and the accessories with ease.Thus,the custom-made type selection of hydraulic torque converters with engineering significance can be successfully implemented.
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