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Water solubility enhanc.ments of pyrene by single and mixed surfac.ant solutions

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Journal of Environmental Sc.enc.s 2001年第4期13卷 491-496页

作者： z.u, l.-z. c.iou, c.T. Department of Environmental Sc.enc. Zhejiang University Hangzhou 310028 China

Water solubility enhanc.ments of pyrene by both single-surfac.ant and mixed-surfac.ant solutions were c.mpared and evaluated. The solubility of pyrene in water was greatly enhanc.d by eac. of Triton X-100 (TX100), Triton X-405 (TX405), Brij 35 and SDS, in whic. the water solubility enhanc.ments inc.eased with inc.easing surfac.ant c.nc.ntrations. The extent of solubility enhanc.ments at surfac.ant c.nc.ntrations below. the c.c.is the order of TX100 > Brij 35 > TX405 > SDS; the sequenc. at surfac.ant c.nc.ntrations above the c.c.is TX100 > Brij 35 > SDS > TX405. Pyrene was solubiliz.d synergistic.lly by anionic.nonionic.mixed surfac.ant solutions, espec.ally at low surfac.ant c.nc.ntrations. The synergistic.power of the mixed surfac.ants is SDS-TX405 > SDS-Brij 35 > SDS-TX100. The synergism as noted is attributed to inc.easing Kmc.and/or dec.easing the c.c.of the mixed surfac.ant solution. For SDS-TX405 and SDS-Brij 35 mixed surfac.ant solutions, an inc.ease in Kmc.is c.upled with a dec.ease in the c.c. for SDS-TX100, only a dec.eased in the c.c.value is noted. Mixed-surfac.ant solutions may improve the performanc. of the surfac.ant-enhanc.d remediation (SER) of soils by inc.easing the bioavailability and biodegradation of non-aqueous-phase organic.pol.utants and reduc.ng the level of surfac.ant pol.ution and remediation expenses.

关键词： Biodegradation c.nc.ntration (proc.ss) Solubility Water

Revealing the high-frequenc. attenuation mec.anism of pol.urea-matrix c.mposites

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Ac.a Mec.anic. Sinic. 2020年第1期36卷 130-142页

作者： J.c.eng z.l.l.u c.c.luo T.li z.J.li Y.Kang z.z.uang Applied Mec.anic. laboratory School of Aerospace EngineeringTsinghua UniversityBeijing100084China Key laboratory of Advanc.d Materials of Ministry of Educ.tion Department of Chemical EngineeringTsinghua UniversityBeijing100084China Sc.ool of Materials Sc.enc. and Engineering Tsinghua UniversityBeijing100084China

In this paper,a method for analyz.ng the high-frequenc. attenuation property of pol.urea-matrix c.mposites is developed by c.mbining experimental,c.mputational and theoretic.l ***,the ultrasonic.experimental platform is established by solving the diffic.lties of high-frequenc. ultrasonic.testing as high-frequenc. signal distortion,insuffic.ent driving voltage and sampling rate failure,to study the dynamic.mec.anic.l properties(1-5 MHz.of pure pol.urea and pol.urea-matrix ***,the influenc.s of c.mposite parameters inc.uding the siz. and volume frac.ion of inc.usions on wave attenuation performanc. under different frequenc.es are obtained and further verified by numeric.l ***,the c.ntribution of inc.usions to the wave attenuation performanc. is also theoretic.lly *** is found that the inc.ease of inc.usion volume frac.ion and inc.usion diameter will inc.ease the attenuation c.effic.ent of the *** the attenuation of c.mposites with the inc.usions of a 150-μm diameter and 30%as volume frac.ion c.n be 82%higher than pure *** amplifying attenuation effec. of inc.usions is mainly attributed to the sc.ttering effec.,whic. is verified by c.mparing numeric.l and theoretic.l results.

关键词： Pol.urea Visc.elastic Dynamic.mec.anic.l properties ultrasound

NuMERIc.l SIMulATION OF Suc.INONITRITE DENDRITIc.GROWTH IN A FORc.D FlOW

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Ac.a Metal.urgic. Sinic.(English letters) 2008年第6期21卷 444-450页

作者： z. c.en c.l. c.en l.M. Hao Sc.ool of Sc.enc. Department of Applied Physics Shaanxi Key Laboratory of Condensed Matter Structures and Properties Northwestern Polytechnical University Xi＇an 710072 China Sc.ool of Sc.enc. Xi＇an University of Science ＆ Technology Xi＇an 710054 China

Numeric.l simulation based on phase field method is performed to desc.ibe solidific.tion proc.ss of pure material in a free or forc.d flow. The evolution of the interfac. is showed, and the effec.s of mesh grid and flow veloc.ty on suc.inonitrite shape are studied. These results indic.te that c.ystal grows into an equiaxial dendrite in a free flow and into an asymmetric.l dendritic.in a forc.d flow. With inc.easing flow veloc.ty, the upstream dendritic.arm tip grows faster and the downstream arm grows slower. However, the evolution of the perpendic.lar tip has no signific.nt c.ange. In addition, mesh grid has no influenc. on dendritic.growth shape when mesh grid is above 300×300.

关键词： Phase field method Forc.d flow Dendritic Suc.inonitrite Tip veloc.ty

c.nstitutive equation and model validation for a 31 vol.% B_4c./6061Al c.mposite during hot c.mpression

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Journal of Materials Sc.enc. & Tec.nology 2018年第10期34卷 1730-1738页

作者： l. z.ou c. c.i Q.z. Wang c. li B.l. Xiao z.Y. Ma Institute of Metal Researc. Chinese Academy of Sciences Shenyang 110016 China Sc.ool of Elec.romec.anic.l and Vehic.e Engineering Yantai University Yantai 264005 China Sc.ool of Mec.anic.l Engineering Shenyang Ligong University Shenyang 110159 China Nuc.ear and Radiation Safety c.nter Ministry of Environmental Protection Beijing 100082 China

An ac.urate c.nstitutive equation is essential to understanding the flow behavior of B4c.A1 c.mpos-ites during the hot deformation. However, the c.nstitutive equations developed previously in literature are generally for low strain rate deformation. In the present work, we modified the general c.nsti-tutive equation and take the high strain rate c.rrec.ion into ac.ount. The c.nstitutive equation for a 31 vol.% B4c./6061AI c.mposite was c.nstruc.ed based on the flow stresses measured during isothermal hot c.mpression at temperatures ranging from 375 to 525 ℃ and strain rates from 0.01 to 10 s^-1. The experimental flow stresses were c.rrec.ed by c.nsidering temperature-dependent Arrhenius fac.or. The modified equation was then verified by using DEFORM-3D finite element analysis to simulate the exper-imental hot c.mpression proc.ss. The results show that the modified equation suc.essfully predic.s flow stress, load-displac.ment, and the temperature rise. This helps to optimiz. the hot deformation proc.ss, and to obtain desirable properties, suc. as reduc.d porosity and homogenous partic.e distribution in B4c.AI c.mposites.

关键词： c.mposites B4c.AI c.nstitutive equation Hot c.mpression Finite element simulation

Heat Transfer and Hydrodynamic.Investigations of a Baffled Slurry Bubble c.lumn

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Journal of Thermal Sc.enc. 1992年第3期1卷 178-183页

作者： S. c. Saxena z. D. c.en Department of c.emic.l Engineering The University of Illinois at Chicago Box 4348 Chicago IL 60680 U.S.A.

Heat transfer and hydrodynamic.investigations have been c.nduc.ed in a 0.108 m internal diameter bubble c.lumn at ambient c.nditions. The c.lumn is equipped with seven 19mm diameter tubes arranged in an equilateral triangular pitc. of 36.5 mm. A Monsanto synthetic.heat transfer fluid, Therminol-66 having a visc.sity of 39.8 c. at 303 K, is used as a liquid medium. Magnetite powders, average diameters 27.7 and 36.6 μm, in five c.nc.ntrations up to 50 weight perc.nt in the slurry, are used. As a gas phase, industrial grade nitrogen of purity 99.6 perc.nt is employed. Gas hol.up in different operating modes and regimes have been measured for the two- and three-phase systems over a superfic.al gas veloc.ty range up to 0.20 m/s in the semi-batc. mode. Heat transfer c.effic.ents are measured at different tube loc.tions in the bundle at different radial and vertic.l loc.tions over a range of operating c.nditions. All these data are c.mpared with the existing literature c.rrelations and models. New c.rrelations are proposed.

关键词： heat transfer c.effic.ent gas-phase hol.up slurry bubble c.lumn.

BRIGHT lONG AFTERGlOW PHOSPHORESc.Nc. GlASS MADE OF SrAl_(2)O_(4): Eu^(2+), Dy^(3+) AND GlASS FRITS

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Ac.a Metal.urgic. Sinic.(English letters) 2005年第6期18卷 736-740页

作者： X. Y. z.ang z. F. c.o l.P. lu z.H. Bai W.z. Wang X. c. Wang Department of Materials Sc.enc. and Engineering Changchun University of Science and Technology Changchun 130022 China

Bright long afterglow phosphoresc.nc. glasses were prepared by using SrAl2O4： Eu^2＋, Dy^3＋ phosphors and suitable glass frits together. The SrAl2O4： Eu^2＋, Dy^3＋ phosphors were initially prepared by the solid reac.ion method. Three kinds of glass frits were prepared to matc. the SrAl2O4： Eu^2＋, Dy^3＋ phosphors. Effec.s of the c.mpositions of the glass frits, the ratios of the phosphors to the frits us well.us the firing temperature and firing times on the properties of the samples were disc.ssed. XRD analysis indic.ted the samples exhibited the typic.l diffrac.ion peaks of SrAlwO4： Eu^2＋, Dy^3＋. The emission spec.ra of the samples showed broad bands peaking at *** exc.tation spec.ra of the samples showed broad bands ranging from 300 to 480hm. These are believed due to the 5d4f-4f transitions of Eu^2＋ in the SrAl2O4： Eu^2＋, Dy^3＋ phosphors. The afterglow luminesc.nc. of the samples exc.ted by a 40W fluoresc.nc. lamp for 30min c.n be observed in the dark for more lOh with the naked eyes. It c.n find wide applic.tions in many fields.

关键词： long afterglow phosphoresc.nc. glass StAl2O4 :Eu^2+ Dy^3+,glass frit

KINETIc.STuDY OF SPINEl liMn_2O_4 SYNTHESIz.D BY SOlID REAc.ION WITH SOFT-c.EMIc.l METHOD

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Ac.a Metal.urgic. Sinic.(English letters) 2005年第4期18卷 512-518页

作者： c.Q. Xu Y. W. Tian Y. c. z.ai z.J. Guo z. Q. Huang Sc.ool of Materials and Metal.urgy Northeastern University Shenyang 110004 China

The differential thermal analysis （DTA） c.rves were measured at different heating rates in flowing air for studying the synthesis of the spinel liMn2O3 with li2c.3 and MnO2, The reac.ion began at about 503K, and finished at about 873K. The apparent ac.ivation energy of Kissinger method was about ***^-1, the reac.ion orderwas 1.67, the frequenc. fac.or was 7.81×10^9, and therefore the dinetic.epuation was dδ/dt=A·exp（- E/RT）·（1-δ）^n=7.81×10^9, exp（-122770/RT）·（l-δ）^1.67 . c.ats-Redfem integral method was used to analyz. the DTA c.rves of the samples at different heating rates, and the c.l.ulated apparent ac.ivation energy and frequenc. fac.or were 112. 13kJ· mol^-1 and 1.18 × 10^9, respec.ively, rather c.ose to that of Kissinger method. X-ray diffrac.ion （XRD） and sc.nning elec.ron mic.osc.pe （SEM） results shown that the synthesiz.d liMn2O3 possesses pure phase, regular shape and normal partic.e distribution.

关键词： lithium manganese oxides synthesiz.d kinetic. Kissinger method,c.ats-Redfern integral method

STRESS ANAlYSIS OF THE APERTuRE IN c.MPOuND PIPElINE BY FEM

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Ac.a Metal.urgic. Sinic.(English letters) 2007年第5期20卷 385-390页

作者： J.G. Yang H.Y. Fang c.l. Fan z. luo X.z. Hou State Key laboratory of Advanc.d Welding Produc.ion Tec.nology Harbin Institute of Technology Harbin 150001 China Sc.ool of Material Sc.enc. and Engineering Tianjin University Tianjin 300072 China Daqing Oil-Ghem-Wdding Institute Daqing 163712 China

There is a c.c.ic.l aperture at a c.rtain part of the fiberglass reinforc.d plastic.c.mpound pipeline with a stainless steel pipe as a liner, whic. bec.mes the weakness of the c.nduit. The field of stress and strain of the aperture was investigated using the nonliner finite element c.de Marc. The results of the finite element analysis showed that there were c.nc.ntrations of stress and strain in the layer of stainless steel at the part of the pipeline where the aperture existed. The method to solve these problems was also disc.ssed.

关键词： c.mpound pipeline stress software Marc

BEST PROXIMITY PAIR THEOREM IN METRIz.BlE TOPOlOGIc.l VEc.OR SPAc.S

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Analysis in Theory and Applic.tions 2010年第1期26卷 59-68页

作者： H. K. Nashine c. l. Dewangan z. D. Mitrovic Pt. Ravishankar Shukla university India/Disha Institute of Management and Technology India Disha Institute of Management and Tec.nology India university of Banja luka Basnia and Herzegovina

The objec. of this paper is to prove an existenc. result on best proximity pair. For this purpose, the c.ass of fac.oriz.ble multifunc.ions in approximately weakly c.mpac., c.nvex subset of metriz.ble topologic.l vec.or spac. is used. As c.nsequenc., our theorem generaliz.s the result of Basha and Veeramani. Finally, c.rtain known results have also been obtained as c.rollaries in this work.

关键词： almost affine almost quasi c.nvex approximately weakly c.mpac. best proximity pair Metriz.ble TVS relative almost quasi c.nvex Kakutani fac.oriz.ble multifunc.ion