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Drag reduction of flow boiling with polymer additives

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Journal of Central South university of technology 2001年第2期8卷 143-146页

作者： QIU Yun ren 1,CHEN Wei ping 2,SI Qin 3 (1.college of chemistry and chemical engineering, Central South university, Changsha 410083, china 2.Editorial Office of Journal of Central South university, Changsha 410083, china 3.college of chemical E 1. college of chemistry and chemical engineering Central South University 410083 Changsha China 2. Editorial Office of Journal of Central South university 410083 Changsha China 3. college of chemical engineering Tianjin University 300072 Tianjin China

The drag reducing effect of polymer additive aqueous solution was investigated in flow boiling, and the polymer additives were two kinds of polyacrylamide (PAM) with relative molecular mass about 2.56×10 6 and 8.55×10 6. The frictional pressure drop was calculated according to the measured total pressure drop. The results show that the flow drag of flow boiling is reduced by adding a small amount of PAM to water when heat flux is in the range of 15.1 kW·m -2 to 47.0 kW·m -2 , when the mass fraction of PAM is higher than 2.0×10 -5 , the drag reducing effect is obvious. Drag reducing effect of PAM, whose relative molecular mass is 8.55×10 6, is slightly better than that of 2.56×10 6 at the same mass fraction, and the greater the flow rate of the additive solution, the better the effect of the drag reduction.

关键词： polymer additive flow boiling drag reduction pressure drop

Effect of surfactants on the structure and photoelectric properties of ITO films by sol-gel method

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Rare Metals 2010年第2期29卷 143-148页

作者： LIU Jiaxiang, WU Da, ZHANG Nan, and WANG Yue college of Materials Science and engineering, Beijing university of chemical technology, Beijing 100029, china college of Materials Science and engineering Beijing University of Chemical Technology

The Indium tin oxide（ITO） thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent *** obtain high-quality ITO films through sol-gel method, the ionic surfactant monoethanolamine and the non-ionic surfactant polyethylene glycol（PEG） were added to the ITO precursor *** influences of surfactants on the structural and photoelectric properties of ITO film samples were *** patterns indicated that surfactant monoethanolamine contributed to film predominant grain orientation along the（400） *** high transmittance（over 95%） was attributed to the preferred orientation and the grain size expansion of ITO *** showed that the surface particle size and the morphology of ITO films were strongly dependent on the kind of surfactants *** to the shortwave region, the absorption edge of the films exhibited the Burstein-Moss shift.

关键词： surfactants indium tin oxide films sol-gel structure photoelectricity

Cycloaddition mechanism for the resin-OsO_4-catalyzed of styrene: A DFT study

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Science china chemistry 2008年第1期51卷 19-24页

作者： ZHANG XingHui1, WANG KeTai1 & FANG Ran2 1 college of chemical engineering, Gansu Unite university, Lanzhou 730000, china 2 college of chemistry and chemical engineering, Sun Yat-sen university, Guangzhou 510275, china college of chemical engineering Gansu Unite UniversityLanzhou 730000China college of chemistry and chemical engineering Sun Yat-sen UniversityGuangzhou 510275China

The postulated intermediates in the base-free and base-assisted addition of OsO4 to styrene have been investigated at the B3LYP/6-311G** level of the theory. N(CH3)2(Ph) was chosen as the base of the resin-OsO4. According to our model calculations the [2+3] addition was found to be favorable with an activation of 155.00 kJ/mol). In addition, the electronic structure analysis of the molecules was carried out by na- ture bond orbital (NBO). The computational results were in reasonable agreement with experimental results.

关键词： cycloaddition resin-OsO4 density functional theory

Electrochemical behaviour of commercially pure titanium and Co-Cr alloy in Ringer's solution

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Rare Metals 2002年第4期21卷 266-270页

作者： LIANG Chenghao and MOU ThanqiSchool of chemical engineering, Dalian university of technology, Dalian 116012, china School of chemical engineering Dalian University of Technology Dalian 116012

The electrochemical behaviors of commercially pure titanium (CP Ti) and Co-Cralloy in Ringer's solution have been investigated. The results indicate that the electric potentialof passive region for CP Ti is up to 3000 mV, and its passive current density is 3.078 μA/cm^*** excellent corrosion resistance of CP Ti can be attributed to the formation of TiO_2 oxide *** passive region of Co-Cr alloy is 770 mV, which is narrower than that of CP Ti. However, nohysteresis loops are found in the reverse scanning curves of Cu-Cr alloy. A complex oxide film ofCo_3O_4, Co_2O_3, and Cr_2O_3 formed on the surface provides Co-Cr alloy with a stableelectrochemistry property. The corrosion rates of the crevice samples increase with the pH value ofmedium decreasing. The electron probe microanalyzer (EPMA) analysis indicates that Ti in CP Ti andCo, Cr in Co-Cr alloy dissolve in crevice area due to the Sealed-Cell effect.

关键词： ringer's solution biomedical material electrochemical behaviors

Water gas shift activity of Co-Mo/MgO-Al_2O_3 catalysts presulfided with ammonium sulfide

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Journal of Natural Gas chemistry 2010年第1期19卷 61-66页

作者： Yixin Lian, Huifang Wang, Weiping Fang, Yiquan Yang Department of chemistry, college of chemistry and chemical engineering, National engineering Laboratory for Green chemical Productions of Alcohols, Ethers and Esters, Xiamen university, Xiamen 361005, Fujian, china [a] Department of chemistry College of Chemistry and Chemical Engineering National Engineering Laboratory for Green Chemical Productions of Alcohols Ethers and Esters Xiamen University Xiamen 361005 Fujian China

Co-Mo/MgO-Al2O3 catalyst was presulfided with ammonium sulfide in aqueous solution and activated with synthesis gas for water gas shift reaction. The assay results indicate that the presulfided Co-Mo/MgO-Al2O3 catalyst exhibits an excellent catalytic activity and stability. XRD and EPR characterization results show that the O-S exchange might occur during the impregnation, leading to the formation of （NH4）2MoS4 （or （NH4）zMoxSy） precursor, which was then thermally decomposed and reduced to MoS2. The higher catalytic performance is attributed to an optimization formation of active Co-Mo sulfides, consisting of well dispersed MoS2 and Co-Mo-S phase due to the redispersion of Co sulfide particles over the edges of newly formed MoS2 crystallites.

关键词： Co-Mo-based catalyst ammonium sulfide presulfidation water-gas shift

Mathematic Expression of Kinetic Compensation Effect and Relationship between the Exothermic Decomposition Temperature and Critical Temperature of Thermal Explosion of Eighty-six Energetic Materials

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含能材料 2001年第1期9卷 8-9页

作者： HU Rong zu 1, YANG De suo 2, ZHANG Jiao qiang 3 (1. Department of chemistry,Northwest university, Xi′an 710065, china 2. Department of chemistry and chemical engineering, Baoji college of Arts and Science, Baoji 721007, china 3. Department of 西北大学陕西西安 710065 宝鸡文理学院陕西 721007 西北工业大学陕西西安 710072

Two relationships are established using the least squares method,between the kinetic parameters (the apparent activation energy and pre exponential constant),and the exothermic decomposition temperature and ther... 详细信息

关键词： critical temperature of thermal explosion decomposition temperature DSC energetic materials.

Catalytic performance of Fe_3O_4-CoO/Al_2O_3 catalyst in ozonation of 2-(2,4-dichlorophenoxy) propionic acid,nitrobenzene and oxalic acid in water

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Journal of Environmental Sciences 2010年第10期22卷 1623-1628页

作者： Shaoping Tong,Rui Shi,Hua Zhang,Chunan Ma college of chemical engineering and Materials Science,State Key Laboratory Breeding Base of Green chemistry-Synthesis technology,Zhejiang university of technology,Hangzhou 310032,china [a] college of chemical engineering Materials Science State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology Zhejiang University of Technology Hangzhou 310032 China

Fe3O4-CoO/Al2O3 catalyst was prepared by incipient wetness impregnation using Fe（NO3）3.9H2O and Co（NO3）2.6H2O as the precursors, and its catalytic performance was investigated in ozonation of 2-（2,4-dichlorophenoxy）propionic acid （2,4-DP）, nitrobenzene and oxalic acid. The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant, and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism. The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance. In the catalytic ozonation of 2,4-DP, the apparent reaction rate constants （k） were determined to be 1.456 × 10^-2 min-1 for ozonation alone and 4.740 × 10^-2 min^-1 for O3/Fe3O4-CoO/Al2O3. And O3/Fe3O4-CoO/Al2O3 had a larger Rot （6.614 × 10^-9） calculated by the relative method than O3 did （1.800 x 10-9）, showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical. Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid. The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.

关键词： catalytic ozonation Fe3O4-CoO/Al2O3 2,4-DP nitrobenzene oxalic acid kinetics

Interface-directed sol-gel:direct fabrication of the covalently attached ultraflat inorganic oxide pattern on functionalized plastics

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Science china chemistry 2010年第1期53卷 173-182,287-288页

作者： GAN ShengHua,YANG Peng & YANG WanTai State Key Laboratory of chemical Resource engineering college of Materials Science and engineering,Beijing university of chemical technology,Beijing 100029,china 1. State Key Laboratory of chemical Resource engineering college of Materials Science and engineering Beijing University of Chemical Technology Beijing 100029 China

For plastic electronics and optics,the fabrication of smooth,transparent and stable crack-free inorganic oxide films(and patterning) on flexible polymeric substrates with strong bonding strength and controllable thickness from nanometers to micrometers is a key but still remains a *** versatile inorganic oxides,silica oxide film as SiOx is especially important because this semiconductor material could provide crucial properties in devices or serve as a base layer for further multilayer *** this paper,we describe a new interface-directed sol-gel method to fabricate flexible high quality silicon oxide film onto commodity *** resulting crack-free silica film has strong covalent bonding with polymer substrates,homogeneous morphology with ultralow roughness,highly optical transparency,tunable thickness from nm to μm,and easy patterning *** fabrication strategy relies on a novel photocatalytic oxidation reaction by photosensitive ammonium persulfate(APS),which is able to fabricate highly reactive hydroxyl monolayer surface on inert polymeric *** kind of hydroxylated surface could serve as nucleation and growth sites to initiate surface sol-gel *** a result,well-defined SiOx film deposition(gelation) occurs,and patterned hydroxylation regions could be easily utilized to induce the formation of patterned oxide film *** strategy also excludes the requirements of clean room and vacuum devices so as to fulfill low-cost and fast fabrication *** application examples from such high quality SiOx layer onto plastics are given but should not be limited within *** is that oxygen permeation rate of SiOx deposited polymer film decreases 25 times than pristine polymer substrate,which is good for the potential packaging *** other one is that silanization monolayer,for example,3-aminopropyltriethoxysilane(APTES),could be successfully constructed onto silica layer through classical silanization reac

关键词： surface patterning silicon oxide sol-gel polymer surface modification functional coatings

Preparation of TiO_2/activated carbon with Fe ions doping photocatalyst and its application to photocatalytic degradation of reactive brilliant red K2G

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Science china chemistry 2009年第8期52卷 1113-1119页

作者： LI YouJi,LI Jing,MA MingYuan,OUYANG YuZhu & YAN WenBin college of chemistry and chemical engineering,Jishou university,Jishou 416000,china 1. college of chemistry and chemical engineering Jishou University Jishou 416000 China

Titanium dioxide coated on activated carbon(AC) with Fe ions doping(Fe-TiO2/AC) composite was prepared by an improved sol-gel *** photocatalytic activities were tested by photocatalytic degradation of reactive brilliant red K2G in *** results show that in comparison with the agglomeration of pure TiO2,the TiO2 nanoparticles are well dispersed in the AC matrix,of which sizes are decreased with Fe ions ***,the iron species on TiO2 of composite are Fe2O3 and FeO,which do not affect the crystalline structures of TiO2 *** AC matrix and iron doping content influence the fluorescence intensity of composite due to their effects on recombination probability of hole-electron *** with TiO2,0.3% Fe-TiO2,TiO2/AC,0.5% Fe-TiO2/AC and 0.1% Fe-TiO2/AC,the 0.3% Fe-TiO2/AC shows the highest photoactivity with the complete mineralization of K2G for finite time due to the optimum Fe ions content and AC ***,the kinetic constant(k=0.0229 min-1) of 0.3% Fe-TiO2/AC composite is more than the sum of both TiO2/AC(0.0154 min-1) and 0.3% Fe-TiO2(0.0057 min-1) because coexistence of the AC and Fe ions has an enlarging effect on improving the photoactivity of TiO2.

关键词： TiO2 nanoparticles Fe ions activated carbon photocatalysis reactive brilliant red K2G