Table of Content

25 October 2013, Volume 41 Issue 10

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Chemistry & Chemical Engineering

Hydrothermal Conversion of Lignosulfonate in Subcritical Water

Wu Shu- bin Li Ji- biao

2013, 41(10):  1-6.  doi:10.3969/j.issn.1000-565X.2013.10.001

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In the investigation,with calcium lignosulfonate as the raw material,hydrothermal experiments were per-formed in a batch reactor,and the effects of the reaction temperature and time on the hydrothermal conversion pro-ducts were discussed by means of GC/MS.The results show that (1) the products are mainly of small molecules,such as phenols,ketones and aldehydes; (2) with the rise of the reaction temperature or with the extension of the reaction time,the contents of H-0,G-0 and G-1- type phenolic compounds of the stable chemical structures in-crease,while the contents of G-3,G-4,G-5- type phenolic compounds of the complicated chemical structures and high relative molecular mass gradually decrease,and no S-1 type phenolic compounds are generated after a long enough time; (3) due to the rise of the reaction temperature and the extension of the reaction time,β- O-4 and α-O-4 linkages largely in lignin become unstable and turn to be broken,thus forming H-0 type,G-0 type,S-0- type units; and (4) under the subcritical water condition above 275℃ and at different reaction time,the guaiacol con-tents in the products are significantly higher than the contents of other phenolic compounds,which indicates that an appropriate control over the reaction temperature and time helps to extract useful phenolic compounds in industry.

Properties of TEMPO- Oxidized Wood Fiber and Its Effects on Paper Properties

Chen Gang Chen Qing- xia

2013, 41(10):  7-12,19.  doi:10.3969/j.issn.1000-565X.2013.10.002

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In the investigation,the wood fibers from butterfly eucalyptus were oxidized in the 2,2,6,6- tetrameth-ylpiperidine-1- oxyradical (TEMPO) / NaBr/ NaClO oxidization system,and the morphologies and properties of the wood fibers before and after oxidation were characterized by using a fiber quality analyzer (FS300),a dynamic drainage jar (DDJ) and an optical microscope.Then,the oxidized fibers were used to prepare the transparent pa-per,and the effects of the NaClO dosage on the paper properties were discussed.The results show that (1) the in-crease of the NaClO dosage with constant TEMPO and NaBr dosages causes an average fiber length decrease of 0.38mm,an average fiber width increase of 4.7μm,a fine fiber content increase of 8 times and a fiber curl value decrease of 13.9 percentage points as well as a poor pulp drainage property; and (2) as compared with the transparent paper from the wood fibers without the TEMPO treatment,that with the TEMPO treatment achieves a higher tensile strength and a greater elastic modulus with a 5 times tensile index,a 7 times elastic modulus and a 27.0% surface roughness as well as a transparency of 87%.

Preparation and Film Properties of Cross- Linking Siliconated Polyurethane- Fluorinated Acrylate Hybrid Emulsion

Xiao Xin- yan Cai Xi- song Wan Cai- xia

2013, 41(10):  13-19.  doi:10.3969/j.issn.1000-565X.2013.10.003

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Siliconated polyurethane (SiPU) emulsion containing the unsaturated double bond was prepared via the solution polymerization,with isophorone diisocyanate (IPDI),polypropylene glycol (PPG),hydroxypropyl termi-nated polydimethyl sioxane (PDMS),trimethylolpropane (TMP),hydroxypropyl methacrylate (HPMA) and dime-thylol propionic acid (DMPA) as main materials.Then,the cross- linking siliconated polyurethane- fluorinated acry-late hybrid emulsion (FSiPUA) was prepared via the radical emulsion polymerization,with SiPU as the seed emul-sion and with butyl acrylate (BA),methyl methacrylate (MMA) and dodecafluoroheptyl methacrylate (DFMA) as the main monomers.Finally,the influences of HPMA,PDMS and DFMA dosages on the emulsion polymerization process and the film properties were discussed,and the PUA emulsion,the SiPUA emulsion and the FSiPUA hybrid emulsion as well as their films were characterized by using a Malvern particle size analyzer and a contact angle me-ter and by means of FT- IR,TG- DSC,XPS and AFM.The results indicate that,when the HPMA,PDMS and DF-MA dosages are respectively 5.2%,7.0% and 20.0%,the FSiPUA hybrid emulsion possesses good water resist-ance and high hydrophobicity,and that,owing to the addition of HPMA,PDMS and DFMA,the thermal stability and mechanical properties of the latex film are greatly improved with a higher surface roughness,a bigger water contact angle,a higher hydrophobicity and a lower water absorption.

Effects of Encapsulation Ratio of Intermediate Layer to Core on Polymeric Hollow Latex Particles

Shao Qing- hui Li Hui Hu Jian- qing Wang Feng Tu Wei- ping

2013, 41(10):  20-25,33.  doi:10.3969/j.issn.1000-565X.2013.10.004

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A series of polymeric hollow latex particles with various encapsulation ratios of intermediate layers to cores were prepared via the alkali swelling method.Then,the products were analyzed in terms of the size and the viscosity and were characterized by means of SEM,TEM and UV- Vis spectrophotometry,and the effects of the encapsulation ratio on the morphology and opacity ability of the products were investigated.The results show that (1) when the encapsulation ratio increases from 6 to 10,the swelling degree of the hollow latex particles decrea-ses,the swelling strength gradually increases,and the opacity ability first increases and then decreases; (2) when the encapsulation ratio is 6 and 7 ,the hollow latex particles are of rough surfaces with higher swelling degrees,bigger cavities and thinner intermediate layers as well as some collapse and rupture; (3) when the encapsulation ratio is 9 and 10,the hollow latex particles are of smooth surfaces with lower swelling degrees,smaller cavities,thicker intermediate layers and with almost no collapse and rupture; and (4) when the encapsulation ratio is 8,the hollow latex particles possess a moderate swelling and achieve the best opacity ability.

Food Science & Technology

Effects of Extraction Methods on Lentinan Properties

Zhao Mou-ming Zou Lin-wu You Li-jun

2013, 41(10):  26-33.  doi:10.3969/j.issn.1000-565X.2013.10.005

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Lentinan was extracted from Lentinus edodes through hot water reflux,high temperature-hot water,ultra-sonic and microwave.Then,these extraction methods were evaluated according to the antioxidant activity,molecular shape and monosaccharide composition of the products.The results show that (1) within the same amount of extrac-tion time,the high temperature-hot water method achieves the maximum lentinan yield rate (14.25%) ; (2) the polysaccharides obtained through high temperature-hot water are of the lowest relative molecular mass; (3) the ap-parent viscosities of the four polysaccharide solutions obtained respectively through the above four extraction me-thods all increase with the increase of the polysaccharide concentration,and they are in the order of hot water reflux ＞microwave ＞ ultrasonic ＞ high temperature-hot water at the same concentration; (4) the high temperature-hot water extraction brings about the polysaccharides with the smallest molecule height and the lowest average rough-ness;(5) different extraction methods all affect the aggregation and branches of polysaccharides to a certain de-gree,thus making the corresponding antioxidant activities in the order of ultrasonic ＞ microwave ＞ hot water re-flux＞ high temperature-hot water; and (6) the polysaccharides obtained through different extraction methods are mainly composed of mannose,glucose and galactose.

Effects of Sulfite on Degradation of 2-Amino-2-Deoxyglucose in Maillard Reaction

Yu Shu-Juan Ma Fei Xu Xian-Bing

2013, 41(10):  34-39,46.  doi:10.3969/j.issn.1000-565X.2013.10.006

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In the investigation,2-amino-2-deoxyglucose,a typical Heyns rearrangement product from the Maillard reaction of fructose and ammonium,was taken as the initial material of the Maillard reaction to react with the sodi-um sulfite with different dosages at 110℃ for 0.5,1.0,2.0,3.0 and 4.0 h.The effects of sodium sulfite on the browning degree of the reaction system was analyzed by means of the UV spectrophotometry,and the effects of sodi-um sulfite on the contents of methylglyoxal and 2-amino-2-deoxyglucose were discussed through the high-perfor-mance liquid chromatography and the anion exchange chromatography.The results show that ( 1) sodium sulfite can significantly inhibit the browning of the reaction system and promote the formation of the cleavage product methylg-lyoxal;( 2) sodium sulfite can not inhibit the degradation of 2-amino-2-deoxyglucose; ( 3) in the reaction system,a small amount of sodium sulfite helps to produce glucose while excessive sodium sulfite can promote the consump-tionof glucose; and ( 4) the effects of sodium sulfite on the fructose content in the reaction system are consistent with those on glucose.

Relative Molecular Mass and Concentration Analyses of Sugarcane Dextran in Mixed Juice with Enzymatic Hydrolysis

Zhao Zhen-gang He Xiang Yu Shu-juan

2013, 41(10):  40-46.  doi:10.3969/j.issn.1000-565X.2013.10.007

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The crude dextran was separated and purified from the mixed juice ( MJ) of sugarcane through ethanolprecipitation,enzymatic hydrolysis and ultrafiltration,and the corresponding relative molecular mass distributionwas characterized by means of GPC. Then,dextranase was used to hydrolyze the dextran in the MJ,and the changelaws of the relative molecular mass and concentration of dextran during the enzymatic hydrolysis were investigated bymeans of GPC and IC.The results show that (1) the relative molecular masses of the dextran in the MJ stored atthe room temperature for 20h are mainly 1.02 × 106 and 3.57 × 103 ; (2) the relative molecular mass of the dextransignificantly decreases with the extension of the reaction time; (3) dextranase can hydrolyze the dextran into theoligosaccharides，which are the final major products; and (4) the concentration change of dextran is related to thecorresponding relative molecular mass change.

Fed-Batch Culture of High Cell-Density Oleaginous Yeast Trichosporon fermentans HWZ004

Zong Min-hua Liu Zong-jun Wu Hong Lou Wen-yong Zhu Ding-he

2013, 41(10):  47-52,65.  doi:10.3969/j.issn.1000-565X.2013.10.008

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In order to improve the ability of oleaginous yeast Trichosporon fermentans HWZ004 to produce lipid，afed-batch culture with high cell density was carried out.The effect of the initial sugar concentration on the growthand lipid accumulation of T. fermentans HWZ004 was investigated and the initial sugar concentration was determinedas 100 g /L,at which T. fermentans HWZ004 could achieve more biomass and higher lipid yield without substrateinhibition. After a 132 h fed-batch culture in a 5-L fermentor,it is found that the biomass,lipid content andlipid productivity of T.fermentans HWZ004 are respectively 102 g /L,48.3% and 0.37 g / ( L·h) .GC results revealthat the fatty acids in the obtained lipid are mainly stearic acid,palmitic acid,oleic acid and linoleic acid，and the unsaturated fatty acid content is over 65%,which means that the lipid is suitable for the biodiesel production.

Molecular Design and Property Validation of Thiazole Orange Monoazide Based on Esterase Activity in Bacteria

Yu Yi-gang Huang Yun Li Xiao-feng Xiao Xing-long Wu Hui

2013, 41(10):  53-59.  doi:10.3969/j.issn.1000-565X.2013.10.009

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In order to develop a new efficient technology for detecting the bacteria alive,a novel fluorescent dye,namely,thiazole orange monoazide ( TOMA),was designed and synthesized based on the metabolic activity of esterasein bacteria,and the molecular structure of TOMA was determined by means of 1H NMR and HRMS. Moreover,the properties of TOMA were preliminarily validated in terms of the intact membrane penetration,the hydrolysisof esterase and the inhibition on the DNA amplification in the PCR.The results show that ( 1) after the treatmentwith 10mg /L TOMA at the room temperature for 10min,the living cells of E.coli O157: H7 emits strong fluorescence,which indicates that TOMA effectively penetrates the intact cell membrane and it possess a good capabilityto bind DNA; ( 2) the hydrolysis rate of TOMA treated by the immobilized lipase is up to 83%，which meansthat the ester bond can be broken by the relevant enzymes; and ( 3) when TOMA is applied to the real-time fluorescentquantitative PCR,the molecular shows an obvious inhibition effect on the DNA amplification.It is thus concludedthat the molecular design of TOMA achieves its desired results.

Hydrolysis Characteristics of β-Amylase on Starches from Different Sources

Huang Qiang Chen Lei Fu Xiong

2013, 41(10):  60-65.  doi:10.3969/j.issn.1000-565X.2013.10.010

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The waxy cornstarch，the normal cornstarch,the potato starch and the tapioca starch were gelatinizedand were then hydrolyzed by using β-amylase,and the hydrolyzates were investigated in terms of the fluidity,thedextrose equivalent ( DE) value，the relative molecular mass distribution,and the thermodynamic property. The resultsshow that ( 1) at the β-amylase dosage of 0.1%，the waxy corn-starch possesses the largest fluidity,while thenormal corn starch possesses the lowest fluidity; ( 2) at the β-amylase dosage of 0.3%,the fluidity of the hydrolyzatesafter a 5 h reaction become stable; ( 3) when the β-amylase dosage is more than 0.3%，the DE values of thehydrolyzates from cereal starches ( i.e. the waxy corn-starch and the normal corn-starch) is greater than those oftube starches( i.e. the potato starch and the tapioca starch) ; ( 4) the relative molecular masses of the hydrolyzatesfrom cereal starches exhibit a narrow distribution,while the relative molecular masses of the hydrolyzates of tubestarches are significantly different and are higher than those of cereal starches; and ( 5) the hydrolyzates of the normalcorn starch show the absorption peaks of the retrograded amylose or the starch-lipid complexes,while thehydrolyzates of the other three starches exhibit no absorption peak.

Influences of Enzymatic Hydrolysis Conditions on Aggregation Structure of Starch Granules

Luo Fa-xing Wu Xiu-ying Huang Qiang Li Chao

2013, 41(10):  66-71.  doi:10.3969/j.issn.1000-565X.2013.10.011

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A series of porous starches with similar hydrolysis rates were prepared by controlling the hydrolysis timeand the enzyme dosage.The influences of the hydrolysis time and the enzyme dosage on the aggregation structure ofstarch granules were investigated by means of SEM,DSC and the small angle X － ray scattering ( SAXS). Experimentalresults indicate that ( 1) at similar hydrolysis rates,starch granules with a shorter hydrolysis time and ahigher enzyme dosage are broken more significantly than those with a longer hydrolysis time and a lower enzymedosage,but the amorphous region and the inner part of the latter were hydrolyzed more seriously with a bigger cavityinside the granules; ( 2) the enthalpy of the starches decreases with the increase of the hydrolysis rate,and it decreasesmore obviously with the extension of the hydrolysis time at a higher hydrolysis rate; and ( 3) during the hydrolysis,the aggregation structures of starch granules change in the amorphous region and the semi － crystalline region;specifically,the hydrolysis time and the enzyme dosage mainly affects the semi － crystalline region and the amorphousregion,respectively.

Materials Science & Technology

Corrosion Behaviors of Cr Low-Alloy Steel in Bottom Plate Environment of Cargo Oil Tanks

Liang Jin-ming Tang Di Wu Hui-bin Zhang Peng-cheng Liu Wei Mao Hong-yan Liu Tiao-tong

2013, 41(10):  72-78,91.  doi:10.3969/j.issn.1000-565X.2013.10.012

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In order to reveal the corrosion mechanism of the bottom plate environment of cargo oil tanks and to developnew low-alloy steels under such environment,a home-made cargo oil tank corrosion simulation device with thestrong-acid Cl- solution corrosion on the bottom plate,was used to investigate the corrosion behaviors of low-alloysteels with different Cr contents.Specifically,the average corrosion rates of the steels in the corrosion test weremeasured with the corresponding morphology observation,and the micromorphologies and element distributions ofthe steels were characterized respectively by means of SEM and EDS.Moreover,the effect of the steel microstructureon the corresponding corrosion-resistance was analyzed by means of EBSD ( Electron Backscattered Diffraction)and TEM,and the polarization curves and AC impedance spectroscopy of the steels with different Cr contents weretested.The results show that ( 1) when the Cr content increases within a range of 1% ～ 3% in the bottom plate environment,the corrosion rate gradually increases and the surface pitting phenomenon becomes obvious; ( 2) withthe increase of the Cr content,the proportion of small-angle low-energy grain boundary and the dislocation densityboth improve,and the changes of the two microstructures both play their roles in the increase of the corrosion rate;and ( 3) the corrosion test results accord well with the electrochemical analysis results.

Texture and Recrystallization of Rolled Mg-1.5Zn-0.2Gd Alloy

Cai Zheng-xu Tang Di Jiang Hai-tao

2013, 41(10):  79-84.  doi:10.3969/j.issn.1000-565X.2013.10.013

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The microstructure,crystal structure and mechanical properties of the hot rolled and annealed Mg-1.5Zn-0.2Gd alloy were investigated by using a metallographic microscope,a SEM and a universal tensile machine.The results show that ( 1) after Mg-1.5Zn-0.2Gd alloy is rolled at 450℃ and subsequently annealed at 350℃ for 60min,the mechanical properties are significantly improved,the texture intensity significantly weakens witha maximum of only 2.3,and the TD split texture appears at ± 30°; ( 2) as compared with the alloys rolled at 450℃,the hot rolled and annealed alloy is of lower yield strength and tensile strength at the room temperature but displaysan excellent elongation which is up to 29.1%; and ( 3) during the annealing,the nucleation in non-basalorientation occurs around the pre-existing grain boundaries,which accounts primarily for the optimized texture ofthe Mg-1.5Zn-0.2Gd alloy.

Effect of Nb Micro-Alloying on Mechanical Properties and Microstructure of NM550 Wear-Resistant Steel

Hu Ri-rong Cai Qing-wu Wu Hui-bin Che Ying-jian

2013, 41(10):  86-91.  doi:10.3969/j.issn.1000-565X.2013.10.014

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The influences of both the addition of Nb and the heat treatment process on the microstructure and mechanicalproperties of NM550 wear-resistant steel were investigated by means of LM ( Light Microscopy) ,SEM andTEM and by mechanical tests.The results show that ( 1) with the increase of the quenching temperature at a temperingtemperature of 200℃,the grain growth of the Nb-free steel is more obvious with the decreases of the tensilestrength and Brinell hardness as well as with a toughness improvement; ( 2) however,the addition of Nb can effectivelyretard the growth of austenite grain,and the re-dissolution of NbC particles increases the alloying elementconcentration in austenite and decreases the size of NbC particles; ( 3) under the combined action of the solutionstrengthening,the precipitation strengthening and the grain refinement strengthening,the Nb-bearing steel showsbetter mechanical properties; and ( 4) when the tempering temperature increases from 200℃ to 250℃,the mechanicalproperties of the two kinds of steels decrease to varying degrees due to the coarsening of carbide,which indicatesthat the tempering at those temperatures should be avoided.

Distribution and Evolution of Retained Austenite in Dual-Phase Steel

Li Hui Duan Lu-zhao Mi Zhen-li Zhao Zheng-zhi Tang Di

2013, 41(10):  92-96.  doi:10.3969/j.issn.1000-565X.2013.10.015

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A certain amount of retained austenite in the dual phase steel was obtained through a rational heat treatmentprocess,and the steel thus achieved a good combination of strength and plasticity.Then,the microstructure ofthe DP steel was investigated by means of the optical metallography,XRD and the electron back-scatter diffraction( EBSD),and the evolution rules of the retained austenite during the deformation were discussed.The results showthat ( 1) the retained austenite is fine and mainly granular,and most of it distributes uniformly at the boundaries offerrites and /or martensites with few in the ferrites; ( 2) the transformation of retained austenite mainly occurs at thedeformation extent of less than10%,and it is linearly related to strain at the deformation extent of more than 10%;and ( 3) in the EBSD observation,the retained austenite is not found in the fractured sample after tensile fracture.

Numerical Simulation of Dispersive Mixing in Flow Field of Particulate Agglomerates with Fractal Structure

Ma Xiang-jun Qiu Zhong-cai Tao Cheng-wen

2013, 41(10):  98-102.  doi:10.3969/j.issn.1000-565X.2013.10.016

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In this paper,a 2-D discrete element program Demix2D is developed to investigate the dispersive mixingmechanism and dynamic details of particulate agglomerates by introducing the van der Waals force and the fluiddrag force into the classic discrete element model. Then,the dispersive mixing process of the agglomerates withfractal structure is numerically simulated in three different flow fields,namely,the steady shear flow field,theelongation flow field and the combined shear and elongation flow field. Simulation results show that ( 1) the agglomeratesin the flow fields first exhibit deformation behavior and then disperse in the manners of erosion and rupture;( 2) under the same flow stress,the elongation flow field has the highest dispersion efficiency with the smallestfinal average fragment size,while the shear flow field has the lowest dispersion efficiency with the largest finalaverage fragment size; and ( 3) with the increase of the flow stress in the same flow field,the dispersion efficiencyincreases and the final average fragment size decreases.

Mechanical and Rheological Properties of Polybutylene Succinate / Epoxidized Soybean Oil Blends

Zhao Yong-qing Chen Fu-quan Wu Zheng-huan Feng Yan-hong Jin Gang Qu Jin-ping

2013, 41(10):  103-107,116.  doi:10.3969/j.issn.1000-565X.2013.10.017

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In the investigation,the melt blending of polybutylene succinate ( PBS) and a novel plasticizer epoxidizedsoybean oil ( ESO) was carried out by using an internal mixer,and a series of PBS /ESO blends were thusprepared.Moreover,the effects of the ESO content on the mechanical and rheological properties of PBS /ESOblends as well as on their morphologies were discussed.The results show that ( 1) the introduction of the ESO significantlyimproves the tensile and impact toughness of the PBS; ( 2) with the increase of the ESO content,theelongation-at-break and the impact strength of the PBS /ESO blends first increase and then decrease,and at the ESOcontent of 5%,they both reach the maximums which are respectively 15.0 and 1,4 times those of PBS; ( 3) thetensile strength,tensile modulus,flexural strength,and flexural modulus of the PBS /ESO blends decrease with theincrease of the ESO content; ( 4) the addition of ESO significantly decrease the complex viscosity of the moltenPBS,thus resulting in an earlier shear-thinning transition of PBS; and ( 5) the PBS /ESO blend with a higher ESOcontent exhibits a distinct phase separation,which indicates that the ESO/PBS blend is a partially miscible system.

Architecture & Civil Engineering

Self-Adaptive Subpopulations-Based Memetic Algorithm and Its Application to Displacement Performance Optimization of Concrete Frames

Wei De-min Chen Gui-tao

2013, 41(10):  108-116.  doi:10.3969/j.issn.1000-565X.2013.10.018

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In this paper,a new memetic algorithm named SaS-MA ( Self-Adaptive Subpopulations-based MemeticAlgorithm) is proposed by combining the differential evolution ( DE) with the covariance matrix adaptation evolutionstrategy ( CMAES) .In order to improve the synergy of the global exploration and local exploitation abilities ofSaS-MA,a self-adaptive subpopulation strategy consisting of the deletion mechanism and the addition mechanism isdesigned.Then,a numerical experiment is implemented to compare SaS-MA with four algorithms,namely,DE,LCMAES,PSO and IP-CMAES.Finally,a ten-story two-bay concrete frame is adopted to carry out the displacementperformance optimization,and the results obtained by using SaS-MA are compared with those obtained from theoriginal paper and through four algorithms,namely,DE,CMA,PSO and GA,which are reliable and widely usedat present.Numerical results indicate that the proposed strategy improves the performance of SaS-MA by means ofdynamic deletion and by constructing subpopulations,and that,SaS-MA is efficient and reliable,and it statisticallyoutperforms the former four existing algorithms.The optimization results show that SaS-MA is more efficient in termsof the concrete frame displacement optimization,and that,as compared with the other four algorithms under thesame conditions,SaS-MA is capable of achieving the best solution,and it possesses excellent optimization abilityand preferable convergence.

Mechanical Behavior of Square CFST Stub Columns with Binding Bars under Axial Compression

Liu Hong-liang Cai Jian

2013, 41(10):  117-125.  doi:10.3969/j.issn.1000-565X.2013.10.019

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In this paper,first,a uniaxial stress-strain relation of the core concrete is proposed for the finite element( FE) analysis of the square concrete-filled steel tubular ( CFST) stub columns with binding bars.Then,based onthe ABAQUS FE platform,a USDFLD subroutine is presented by considering the Poisson ratio changes and the nonlinearconstitutive relation of many materials in the loading process,and a FE model is then established to simulatethe square CFST stub columns.Finally，the mechanical behavior of the square CFST stub columns is discussed interms of the stress-strain relation and the confined effect among the steel tube,the core concrete and the bindingbars,as well as of the longitudinal stress distribution of the core concrete.The results show that ( 1) the computationresults obtained through the proposed FE model accord well with the test results; ( 2) the binding bars can delaythe local buckling of the steel tube and thus make the steel tube yield before the ultimate strength of the specimenoccurs,and they can also improve the concrete confinement of the corner and central regions and thus increasethe longitudinal stress of the core concrete,so that the bearing capacity and ductility of the specimen can be improved;and ( 3) the concrete confinement of the corner and the central regions increases with the decrease of thespacing between the binding bars

Axial Compressive Behavior of Stiffened Square Concrete-Filled Steel Tubular Stub Columns Under Axial Load

Zheng Xin-zhi Cai Jian Zheng Xin-hua

2013, 41(10):  126-134.  doi:10.3969/j.issn.1000-565X.2013.10.020

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Seven concrete-filled steel tubular stub columns with different structures were investigated by an axialcompressive test in terms of the ultimate axial bearing capacity,the characteristics of the axial compressive failureand deformation,the ductility and the steel consumption.Experimental results indicate that ( 1) under axial compressiveloads,the restraint of the CFST column with binding bars on the core concrete is obviously improved,butthe corresponding distribution is uneven,thus limiting the increase of the overall strength and ductility of the concrete;( 2) as compared with the common square CFST column,the stiffened square CFST column uses less steeland achieves a more even restraint distribution,a better overall restraint effect,a greater axial bearing capacity,and a better ductility as well as less local buckling between the binding bars; and ( 3) the width-thickness ratio ofthe square CFST column greatly affects the corresponding axial compressive behavior; specifically,the bearing capacityductility coefficient of the CFST column as well as the longitudinal strain corresponding to the local bucklingincreases with the decrease of the width-thickness ratio.

Satisfaction Evaluation on Modern Comprehensive Theater Based on Subjective Evaluation Method: Guangzhou Opera House and Hunan Opera House

Chen Xiang-rong Wu Shuo-xian

2013, 41(10):  135-144.  doi:10.3969/j.issn.1000-565X.2013.10.021

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First,with the aid of satisfaction research methods and by using questionnaires,some modern comprehensivetheaters are evaluated by the users,namely,the audience and the actors.The survey results are then comparedthrough the mean value analysis,the variance analysis and the correlation analysis,with the users and thetheaters as the controlled variables.Next,the main problems of the theaters are discussed based on the analysis results.Then,by means of the AHP ( Analytic Hierarchy Process) method,a two-level analysis system is established,and the top ten influential evaluation factors and the weight of each evaluation factor are obtained,whichcan provide guidelines for the architectural design of theaters in the future. Finally,the survey results,the correlationanalysis and the weight of each factor are compared. It is thus concluded that the obtained weights of satisfactionevaluation indexes are rational.