The apparent sulfur oxidation activities of four pure thermophilic archaea, Acidianus brierleyi （JCM 8954）, Metallosphaera sedula （YN 23）, Acidianus manzaensis （YN 25） and Sulfolobus metallicus （YN 24） and the...The apparent sulfur oxidation activities of four pure thermophilic archaea, Acidianus brierleyi （JCM 8954）, Metallosphaera sedula （YN 23）, Acidianus manzaensis （YN 25） and Sulfolobus metallicus （YN 24） and their mixture in bioleaching chalcopyrite were compared, which were characterized indirectly by the evolution of the cells concentration, pH value and sulfate ions concentration in solution. The results show that the mixed culture contributed significantly to the raising of leaching rate, which suggests that the mixed culture had a higher sulfur oxidation activity than the pure culture. Meanwhile, the results also indicate that the changes of parameters characterizing the sulfur oxidation activity of thermophilic archaea are often influenced by many factors, so it is hard to reflect accurately the specific sulfur oxidation activities among the different sulfur-oxidizing microbes when bioleaching chalcopyrite at different conditions. Accordingly, an efficient method to characterize microbial sulfur oxidation activity appears to be desirable.展开更多
To shorten the fabrication process of difficult-to-form TiAl sheets, twin-roll strip casting and microstructural control were investigated in Ti-43Al alloy. A crack-free sheet with dimensions of 1000 mm × 110 mm ...To shorten the fabrication process of difficult-to-form TiAl sheets, twin-roll strip casting and microstructural control were investigated in Ti-43Al alloy. A crack-free sheet with dimensions of 1000 mm × 110 mm × 2 mm was obtained. The microstructure of stip casting sheets and heat treatments was systematically studied. The macrostructure consisted of columnar crystals extending inward and centrally located equiaxed crystals with severe Al segregation were observed along the thickness direction, due to the symmetrical solidification process and decreasing cooling rates. The strip casting alloy was characterized by fine duplex microstructure with a grain spacing of 20-30 μm and a lamellar spacing of 10-20 nm. Furthermore, multiple microstructures of near gamma, nearly lamellar and fully lamellar were obtained through heat treatment process with significantly improved homogeneity of the microstructure.展开更多
Extracellular manganese peroxidases （MnPs） produced by native and mutant strains of Trametes versicolor IBL‐04 （EB‐60, EMS‐90） were purified by ammonium sulphate precipitation and dialysis, followed by ion‐exc...Extracellular manganese peroxidases （MnPs） produced by native and mutant strains of Trametes versicolor IBL‐04 （EB‐60, EMS‐90） were purified by ammonium sulphate precipitation and dialysis, followed by ion‐exchange and gel‐permeation chromatography. The purified enzymes elucidated a single band in the 43‐kDa region on sodium dodecyl sulphate‐polyacrylamide gel electrophoresis. The optimum pH and temperature of the purified enzymes were found to be 5.0 and 40 °C, respec‐tively. Mutant strain MnPs exhibited a broader active pH range and higher thermal stability than native MnP. Purified MnPs from selected mutants showed almost identical properties to native MnP in electrophoresis, steady‐state kinetics, and metal ion and endocrine‐disrupting compound （EDC） degradation efficiency. Although the fastest reaction rates occurred with Mn2＋, MnPs displayed the highest affinity for ABTS, methoxyhydroquinone, 4‐aminophenol and reactive dyes. MnP activity was significantly enhanced by Mn2＋and Cu2＋, and inhibited in the presence of Zn2＋, Fe2＋, ethylene‐diaminetetraacetic acid and cysteine to various extents, with Hg2＋ as the most potent inhibitory agent. MnPs from all sources efficiently catalyzed the degradation of the EDCs, nonylphenol and triclosan, removing over 80%after 3 h of treatment, which was further increased up to 90%in the presence of MnP‐mediator system. The properties of T. versicolor MnPs, such as high pH and ther‐mal stability, as well as unique Michaelis‐Menten kinetic parameters and high EDC elimination effi‐ciency, render them promising candidates for industrial exploitation.展开更多
A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR ...A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR （nuclear magnetic resonanse） spectroscopy and the dependence of the cured materials properties on the composition was established. Increase of a propargyl content resulted in char yield raise and the maximum value had been found for propargylated resin--58%. DSC （differential scanning calorimetry）-analysis of the resins has demonstrated that exothermic enthalpy of the curing process could be adjusted by varying the content of propargyl and allyl groups in the resin.展开更多
In this study, the water-based ferromagnetic fluid and magnetic resin made from chitosan and cerium complex （MRCCC） were successfully prepared by using the chemical co-precipitation technique and by the reversed-pha...In this study, the water-based ferromagnetic fluid and magnetic resin made from chitosan and cerium complex （MRCCC） were successfully prepared by using the chemical co-precipitation technique and by the reversed-phase suspension cross-linking polymerization. MRCCC presented uniform and narrow panicle size distribution as determined by the Laser Panicles Sizer. The Inductively Coupled Plasma-Atomic Emission Spectrometry （ICP-AES）, Fourier transform infrared spectroscopy （FT-IR）, differential scanning calorimetry （DSC） and X-ray powder diffraction （XRD） study demonstrated that there were iron and cerium existing in MRCCC. The movement of MRCCC under magnetic field proved its magnetic property. The swelling kinetics in water or solutions with different pH indicated that MRCCC could be applied in solutions with pH greater than 1.0. The ferromagnetic fluid particles were stable in MRCCC soaked in solutions with pH 〉2.0. In view of these results, MRCCC can be used as material for separation, clarification, adsorption, sustained release and hydrolysis activity.展开更多
As one of the key boundary conditions during casting solidification process, the interfacial heat transfer coefficient (IHTC) affects the temperature variation and distribution. Based on the improved nonlinear estimat...As one of the key boundary conditions during casting solidification process, the interfacial heat transfer coefficient (IHTC) affects the temperature variation and distribution. Based on the improved nonlinear estimation method (NEM), thermal measurements near both bottom and lateral metal-mold interfaces throughout A356 gravity casting process were carried out and applied to solving the inverse heat conduction problem (IHCP). Finite element method (FEM) is employed for modeling transient thermal fields implementing a developed NEM interface program to quantify transient IHTCs. It is found that IHTCs at the lateral interface become stable after the volumetric shrinkage of casting while those of the bottom interface reach the steady period once a surface layer has solidified. The stable value of bottom IHTCs is 750 W/(m^2·℃), which is approximately 3 times that at the lateral interface. Further analysis of the interplay between spatial IHTCs and observed surface morphology reveals that spatial heat transfer across casting-mold interfaces is the direct result of different interface evolution during solidification process.展开更多
Hafnium ethoxide was synthesized using electrochemical method.Optimization experiments were used to optimizevarious parameters namely Et4NBr concentration(c):0.01?0.06mol/L,solution temperature(t):30?78°C,polar d...Hafnium ethoxide was synthesized using electrochemical method.Optimization experiments were used to optimizevarious parameters namely Et4NBr concentration(c):0.01?0.06mol/L,solution temperature(t):30?78°C,polar distance(D):2.0?4.0cm and current density(J):100?400A/m2.The electrolytic products obtained under optimum conditions of c=0.04mol/L,t=78°C,D=2.0cm and J=100A/m2were further isolated by vacuum distillation under5kPa.The product was characterized byFourier transform infrared(FT-IR)spectra,nuclear magnetic resonance(NMR)spectra.The results indicated that the product washafnium ethoxide.ICP analysis suggested that the content of hafnium ethoxide in the final product exceeded99.997%.Thermalproperties of the product were analyzed by TG/DTG.The vaporization enthalpy of hafnium ethoxide was found to be79.1kJ/mol.The result confirmed that hafnium ethoxide was suitable for the preparation of hafnium oxide by atomic layer deposition.展开更多
Asphaltene-ceramic composite membranes were fabricated from ceramic supports and an asphaltene component, which was obtained from the separation of coal to give a kind of new carbonaceous precursor material. Using SEM...Asphaltene-ceramic composite membranes were fabricated from ceramic supports and an asphaltene component, which was obtained from the separation of coal to give a kind of new carbonaceous precursor material. Using SEM and thermogravimetric analysis to measure the microstructure and properties of the asphaltene component allowed the porosity, permeability, and retention ratios to be determined. The results show that the asphaltene component can be regarded as a good carbon membrane precursor material because of its high carbon content and strong bonding capacity. When ceramic supports are impregnated with asphaltene colloid the asphaltene easily combines with the support surface and forms a good carbonaceous film after carbonization. Little of the asphaltene component permeates into the internal pores of the ceramic support. Although the number of coats applied to the substrate had little affect on the porosity of the asphaltene-ceramic composite membranes the permeability varied depend- ing upon the number of times the substrate was treated. The way bubbles escape from the film, and the phenomenon of coalescence, as affected by different film thicknesses also seem closely related to the number of coats. A composite membrane carbonized at a final temperature of 600℃ is relatively dense and the permeability of Fe（OH）3 colloid through it is very low. A membrane fired at 800℃ is porous and its permeability and retention of Fe（OH）3 colloid are 88 L/（m2 h MPa） and 85.3%, respectively when the trans-membrane pressure is 0.22 MPa.展开更多
A simple electrochemical method for the in situ preparation of homogeneously dispersed gold-polyaniline core/shell nanocomposite particles with controlled size on the highly oriented pyrolytic graphite(HOPG)was demons...A simple electrochemical method for the in situ preparation of homogeneously dispersed gold-polyaniline core/shell nanocomposite particles with controlled size on the highly oriented pyrolytic graphite(HOPG)was demonstrated.The HOPG surface was modified preferentially by covalent bonding of a two-dimensional 4-aminophenyl monolayer employing diazonium chemistry.AuCl4 -ions were attached to the Ar-NH2 termination and reduced electrochemically.This results in the formation of Au nuclei that could be further grown into gold nanoparticles.The formation of polyaniline as the shell wrap of Au nanoparticle was established by localized electro-polymerization.These core-shell nanocomposites prepared were characterized by AFM and cyclic voltammetry.The results show that the gold-polyaniline core-shell composites on HOPG have a mean particle size of 100 nm in diameter and the polyaniline shell thickness is about 15 nm.展开更多
Fluorosilicone oil is polysiloxane with alkyl side chains containing fluorine, and because of its excellent thermal oxidation stability, cold flow property and cryogenic property, it can be widely used as a high tempe...Fluorosilicone oil is polysiloxane with alkyl side chains containing fluorine, and because of its excellent thermal oxidation stability, cold flow property and cryogenic property, it can be widely used as a high temperature lubricant in the field of military aerospace industry. Two kinds of fluorosilicone oils, FSiO-a and FSiO-b, were synthesized by different pro- cessing means. FTICR MS was used to collect the information on composition and structure of the two polymers, respec- tively. The test results show that the two fluorosilicone oils have different contents of fluorine-containing chain segments (m/ n value), the maximum distribution of m/n value of FSiO-a oil ranges from 0.22 to 0.25, and that of FSiO-b oil ranges from 0.4 to 0.67. Difference in synthesis techniques makes this discrepancy and affects the quality and thermal stability of the fluoro- silicone oils.展开更多
Zinc Oxide （ZnO） nanostructure were synthesized by precipitating Zinc Chloride and analyzed structurally and optically. Samples were prepared at different thickness （62, 66, 74, 86, 92, and 110 nm）, and substrate ...Zinc Oxide （ZnO） nanostructure were synthesized by precipitating Zinc Chloride and analyzed structurally and optically. Samples were prepared at different thickness （62, 66, 74, 86, 92, and 110 nm）, and substrate temperature kept at 400 ℃ in all cases. Compressed Nitrogen was used as a cartier gas. The samples of the ZnO films were characterized by X-ray diffraction （XRD）, and atomic force microscopy （AFM）. The XRD results indicated that the synthesized ZnO thin films have a pure wurtzite （hexagonal phase） structure. It can be seen that the highest texture coefficient was in （002） plan for nanostructure films. AFM measurement showed the grain size ranging from 62-86 nm. The optical band gap energy （Ee,） of ZnO nanostructure have two values for the same sample and the Eg decrease with increasing thickness utilizing the optical data using UV-Vis spectrophotometer.展开更多
Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non...Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non-linear but increasing relations of both geo-temperatures and geothermal gradients with increases depth. Numerically, we fitted the relationship between geo-temperatures and depth, a first-order exponential decay curve, formulated as: T(h) = 4.975 + 23.08 exp(h/1736.1).展开更多
Thailand rice husk ash was used to synthesize zeolite by hydrothermal treatment. Raw rice husk ash material and zeolitic products were characterized in terms of specific surface area （BET method）, morphological anal...Thailand rice husk ash was used to synthesize zeolite by hydrothermal treatment. Raw rice husk ash material and zeolitic products were characterized in terms of specific surface area （BET method）, morphological analysis （SEM）, mineralogical composition （XRD） and CEC （cation exchange capacity）. LOI （Loss of ignition） of rice husk ash was also evaluated. Result indicated that the rice husk ash sample from Roi-Et Green power plant in the Northeastern of Thailand with combustion temperature of 650 ℃ has a high content of SiO2 （above 90 wt.%）. Zeolite-X from rice husk ash with high content of Si was successfully synthesized using hydrothermal treatment. The zeolitic material synthesized with the optimal condition possessed a maximum value of CEC of 503 meq/100g, and it has potentiality to be used as ion exchangers.展开更多
A novel metal（II）-organic complex Co（HIMP）（1,4-bdc）＇3H20 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffxaction. The complex is a mononuclear Co（II） complex, wh...A novel metal（II）-organic complex Co（HIMP）（1,4-bdc）＇3H20 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffxaction. The complex is a mononuclear Co（II） complex, which is assembled into a 3D supramolecular architecture via strong intermolecular π…π stacking interactions and hydrogen bonds.展开更多
In order to obtain anatase TiO2/expanded graphite with high expansion volume, titania gel was introduced to expandable graphite surface by sol-gel process, and then the composite was expanded and calcined at high temp...In order to obtain anatase TiO2/expanded graphite with high expansion volume, titania gel was introduced to expandable graphite surface by sol-gel process, and then the composite was expanded and calcined at high tempera- ture. The samples were analysed by using scanning electron microscope （SEM）, X-ray diffraction（XRD）, energy disperse spectroscopy （EDS）, and differential scanning calorimetry （DSC）. The optimal conditions for preparation are as follows： the molar ratio of tetrabutyl orthotitanate to triethanolamine is 1 ： 0.4, and the calcination and expansion temperature is in the range of 650--750 ~C. Under such conditions, the expansion volume of composites could reach 98 mE/g, and the mass loss ratio is less than 5%. The analysis shows that lower temperature and smaller particle size of graphite are helpful to the formation of anatase-type of TiO2, but larger particle size will lead to lower mass loss ratio, and higher temperature and larger particle size will lead to higher expansion volume.展开更多
Hydroxyl radicals, superoxide anions and nitricoxide radicals are reactive species that can attack biomolecules such as DNA, lipids and proteins to cause many lifestyle-related diseases including hypertension and phot...Hydroxyl radicals, superoxide anions and nitricoxide radicals are reactive species that can attack biomolecules such as DNA, lipids and proteins to cause many lifestyle-related diseases including hypertension and photoaging. This study reports the synthesis of new copper-pyridoxine and iron-pyridoxine complexes. The complexes have been synthesized and characterized by molar conductances, IR, UV-Visible, mass spectrometry, melting points and magnetic moment datas. The molecular formula of the complex is found to be Fe（py ^-）2Cl.H2O. The pyH/pyligand is coordinated to copper and iron through N atom of the pyridine ring and O atom of 5＇-CH2OH group. The Fe（III） complex is found to be paramagnetic with one unpaired electron. The antioxidant activities of the free ligand and its complexes were determined in vitro.展开更多
Residual stress continues to be important issues in shipbuilding. This paper demonstrates how the heat affected zone that results from welding could be identified nondestructively using MBN （magnetic Barkhausen noise...Residual stress continues to be important issues in shipbuilding. This paper demonstrates how the heat affected zone that results from welding could be identified nondestructively using MBN （magnetic Barkhausen noise） technique. A stress concentration region was created by placing a weld bead on a marine steel plate used in ship construction. MBN measurements were made on the back surface of the welded plate along the weld direction and perpendicular to it in a line that crosses the weld bead. The stress distribution as deduced from the MBN measurements was found to be anisotropic in the material of the heat affected zone. The heat induced anisotropy was completely eliminated by shot peening the HAZ material as revealed by MBN intensity. It was concluded that the directional MBN measurements could be used to characterize the induced anisotropy and hence assess the thermal residual stresses distribution near a localized stresses concentration regions imposed by welding.展开更多
基金Project(50974140) supported by the National Natural Science Foundation of ChinaProject(20090162110054) supported by Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The apparent sulfur oxidation activities of four pure thermophilic archaea, Acidianus brierleyi （JCM 8954）, Metallosphaera sedula （YN 23）, Acidianus manzaensis （YN 25） and Sulfolobus metallicus （YN 24） and their mixture in bioleaching chalcopyrite were compared, which were characterized indirectly by the evolution of the cells concentration, pH value and sulfate ions concentration in solution. The results show that the mixed culture contributed significantly to the raising of leaching rate, which suggests that the mixed culture had a higher sulfur oxidation activity than the pure culture. Meanwhile, the results also indicate that the changes of parameters characterizing the sulfur oxidation activity of thermophilic archaea are often influenced by many factors, so it is hard to reflect accurately the specific sulfur oxidation activities among the different sulfur-oxidizing microbes when bioleaching chalcopyrite at different conditions. Accordingly, an efficient method to characterize microbial sulfur oxidation activity appears to be desirable.
基金Project(51504060) supported by the National Natural Science Foundation of ChinaProjects(2016YFB0301201,2016YFB0300603) supported by the National Key Research and Development Program of ChinaProject(N160713001) supported by the Fundamental Research Funds for the Central Universities,China
文摘To shorten the fabrication process of difficult-to-form TiAl sheets, twin-roll strip casting and microstructural control were investigated in Ti-43Al alloy. A crack-free sheet with dimensions of 1000 mm × 110 mm × 2 mm was obtained. The microstructure of stip casting sheets and heat treatments was systematically studied. The macrostructure consisted of columnar crystals extending inward and centrally located equiaxed crystals with severe Al segregation were observed along the thickness direction, due to the symmetrical solidification process and decreasing cooling rates. The strip casting alloy was characterized by fine duplex microstructure with a grain spacing of 20-30 μm and a lamellar spacing of 10-20 nm. Furthermore, multiple microstructures of near gamma, nearly lamellar and fully lamellar were obtained through heat treatment process with significantly improved homogeneity of the microstructure.
基金a part of a research project entitled "The development of immobilized ligninolytic enzymes for industrial applications" supported by Higher Education Commission (HEC), Islamabad, Pakistan
文摘Extracellular manganese peroxidases （MnPs） produced by native and mutant strains of Trametes versicolor IBL‐04 （EB‐60, EMS‐90） were purified by ammonium sulphate precipitation and dialysis, followed by ion‐exchange and gel‐permeation chromatography. The purified enzymes elucidated a single band in the 43‐kDa region on sodium dodecyl sulphate‐polyacrylamide gel electrophoresis. The optimum pH and temperature of the purified enzymes were found to be 5.0 and 40 °C, respec‐tively. Mutant strain MnPs exhibited a broader active pH range and higher thermal stability than native MnP. Purified MnPs from selected mutants showed almost identical properties to native MnP in electrophoresis, steady‐state kinetics, and metal ion and endocrine‐disrupting compound （EDC） degradation efficiency. Although the fastest reaction rates occurred with Mn2＋, MnPs displayed the highest affinity for ABTS, methoxyhydroquinone, 4‐aminophenol and reactive dyes. MnP activity was significantly enhanced by Mn2＋and Cu2＋, and inhibited in the presence of Zn2＋, Fe2＋, ethylene‐diaminetetraacetic acid and cysteine to various extents, with Hg2＋ as the most potent inhibitory agent. MnPs from all sources efficiently catalyzed the degradation of the EDCs, nonylphenol and triclosan, removing over 80%after 3 h of treatment, which was further increased up to 90%in the presence of MnP‐mediator system. The properties of T. versicolor MnPs, such as high pH and ther‐mal stability, as well as unique Michaelis‐Menten kinetic parameters and high EDC elimination effi‐ciency, render them promising candidates for industrial exploitation.
文摘A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR （nuclear magnetic resonanse） spectroscopy and the dependence of the cured materials properties on the composition was established. Increase of a propargyl content resulted in char yield raise and the maximum value had been found for propargylated resin--58%. DSC （differential scanning calorimetry）-analysis of the resins has demonstrated that exothermic enthalpy of the curing process could be adjusted by varying the content of propargyl and allyl groups in the resin.
基金supported by the Key Projects in the National Science and Technology Pillar Program during the Eleventh Five-year Plan Period(No.2008BA-D94B09)the National Natural Science Foundation of China(No.30972289)
文摘In this study, the water-based ferromagnetic fluid and magnetic resin made from chitosan and cerium complex （MRCCC） were successfully prepared by using the chemical co-precipitation technique and by the reversed-phase suspension cross-linking polymerization. MRCCC presented uniform and narrow panicle size distribution as determined by the Laser Panicles Sizer. The Inductively Coupled Plasma-Atomic Emission Spectrometry （ICP-AES）, Fourier transform infrared spectroscopy （FT-IR）, differential scanning calorimetry （DSC） and X-ray powder diffraction （XRD） study demonstrated that there were iron and cerium existing in MRCCC. The movement of MRCCC under magnetic field proved its magnetic property. The swelling kinetics in water or solutions with different pH indicated that MRCCC could be applied in solutions with pH greater than 1.0. The ferromagnetic fluid particles were stable in MRCCC soaked in solutions with pH 〉2.0. In view of these results, MRCCC can be used as material for separation, clarification, adsorption, sustained release and hydrolysis activity.
基金Project(TC160A310-10-01)supported by the National Industry Base Enhanced Program,ChinaProjects(2015B090926002,2013A090100002)supported by Science and Technology of Guangdong Province,ChinaProject(2016AG100932)supported by Key Technology Program of Foshan,China
文摘As one of the key boundary conditions during casting solidification process, the interfacial heat transfer coefficient (IHTC) affects the temperature variation and distribution. Based on the improved nonlinear estimation method (NEM), thermal measurements near both bottom and lateral metal-mold interfaces throughout A356 gravity casting process were carried out and applied to solving the inverse heat conduction problem (IHCP). Finite element method (FEM) is employed for modeling transient thermal fields implementing a developed NEM interface program to quantify transient IHTCs. It is found that IHTCs at the lateral interface become stable after the volumetric shrinkage of casting while those of the bottom interface reach the steady period once a surface layer has solidified. The stable value of bottom IHTCs is 750 W/(m^2·℃), which is approximately 3 times that at the lateral interface. Further analysis of the interplay between spatial IHTCs and observed surface morphology reveals that spatial heat transfer across casting-mold interfaces is the direct result of different interface evolution during solidification process.
基金Project(51374254) supported by the National Natural Science Foundation of China
文摘Hafnium ethoxide was synthesized using electrochemical method.Optimization experiments were used to optimizevarious parameters namely Et4NBr concentration(c):0.01?0.06mol/L,solution temperature(t):30?78°C,polar distance(D):2.0?4.0cm and current density(J):100?400A/m2.The electrolytic products obtained under optimum conditions of c=0.04mol/L,t=78°C,D=2.0cm and J=100A/m2were further isolated by vacuum distillation under5kPa.The product was characterized byFourier transform infrared(FT-IR)spectra,nuclear magnetic resonance(NMR)spectra.The results indicated that the product washafnium ethoxide.ICP analysis suggested that the content of hafnium ethoxide in the final product exceeded99.997%.Thermalproperties of the product were analyzed by TG/DTG.The vaporization enthalpy of hafnium ethoxide was found to be79.1kJ/mol.The result confirmed that hafnium ethoxide was suitable for the preparation of hafnium oxide by atomic layer deposition.
基金the National Natural Science Foundation of China (Nos.50874108 and 50921002)the Natural Science Foundation of Jiangsu Province (No.BK2007038)+2 种基金the Fundamental Research Funds for the Central Universities (No.2010LKHX01)the Open Fund of Key Laboratory of Coal ProcessClean Utilization of Ministry of Education (No.CPEUKF08-06)
文摘Asphaltene-ceramic composite membranes were fabricated from ceramic supports and an asphaltene component, which was obtained from the separation of coal to give a kind of new carbonaceous precursor material. Using SEM and thermogravimetric analysis to measure the microstructure and properties of the asphaltene component allowed the porosity, permeability, and retention ratios to be determined. The results show that the asphaltene component can be regarded as a good carbon membrane precursor material because of its high carbon content and strong bonding capacity. When ceramic supports are impregnated with asphaltene colloid the asphaltene easily combines with the support surface and forms a good carbonaceous film after carbonization. Little of the asphaltene component permeates into the internal pores of the ceramic support. Although the number of coats applied to the substrate had little affect on the porosity of the asphaltene-ceramic composite membranes the permeability varied depend- ing upon the number of times the substrate was treated. The way bubbles escape from the film, and the phenomenon of coalescence, as affected by different film thicknesses also seem closely related to the number of coats. A composite membrane carbonized at a final temperature of 600℃ is relatively dense and the permeability of Fe（OH）3 colloid through it is very low. A membrane fired at 800℃ is porous and its permeability and retention of Fe（OH）3 colloid are 88 L/（m2 h MPa） and 85.3%, respectively when the trans-membrane pressure is 0.22 MPa.
基金Project(50721003)supported by the Creative Research Group of National Natural Science Foundation of ChinaProject(50825102)supported by the National Science Fund for Distinguished Young Scholars,China
文摘A simple electrochemical method for the in situ preparation of homogeneously dispersed gold-polyaniline core/shell nanocomposite particles with controlled size on the highly oriented pyrolytic graphite(HOPG)was demonstrated.The HOPG surface was modified preferentially by covalent bonding of a two-dimensional 4-aminophenyl monolayer employing diazonium chemistry.AuCl4 -ions were attached to the Ar-NH2 termination and reduced electrochemically.This results in the formation of Au nuclei that could be further grown into gold nanoparticles.The formation of polyaniline as the shell wrap of Au nanoparticle was established by localized electro-polymerization.These core-shell nanocomposites prepared were characterized by AFM and cyclic voltammetry.The results show that the gold-polyaniline core-shell composites on HOPG have a mean particle size of 100 nm in diameter and the polyaniline shell thickness is about 15 nm.
文摘Fluorosilicone oil is polysiloxane with alkyl side chains containing fluorine, and because of its excellent thermal oxidation stability, cold flow property and cryogenic property, it can be widely used as a high temperature lubricant in the field of military aerospace industry. Two kinds of fluorosilicone oils, FSiO-a and FSiO-b, were synthesized by different pro- cessing means. FTICR MS was used to collect the information on composition and structure of the two polymers, respec- tively. The test results show that the two fluorosilicone oils have different contents of fluorine-containing chain segments (m/ n value), the maximum distribution of m/n value of FSiO-a oil ranges from 0.22 to 0.25, and that of FSiO-b oil ranges from 0.4 to 0.67. Difference in synthesis techniques makes this discrepancy and affects the quality and thermal stability of the fluoro- silicone oils.
文摘Zinc Oxide （ZnO） nanostructure were synthesized by precipitating Zinc Chloride and analyzed structurally and optically. Samples were prepared at different thickness （62, 66, 74, 86, 92, and 110 nm）, and substrate temperature kept at 400 ℃ in all cases. Compressed Nitrogen was used as a cartier gas. The samples of the ZnO films were characterized by X-ray diffraction （XRD）, and atomic force microscopy （AFM）. The XRD results indicated that the synthesized ZnO thin films have a pure wurtzite （hexagonal phase） structure. It can be seen that the highest texture coefficient was in （002） plan for nanostructure films. AFM measurement showed the grain size ranging from 62-86 nm. The optical band gap energy （Ee,） of ZnO nanostructure have two values for the same sample and the Eg decrease with increasing thickness utilizing the optical data using UV-Vis spectrophotometer.
基金Financial support for this project,provided by the National Basic Research Program of China (No.2006CB202200)the Key Project of National Natural Science Foundation of China+1 种基金the Program for Changjiang Scholars,Innovative Research Team in University of China (No.IRT0656)the Fundamental Research Funds for the Central Universities (No.2010QL04)
文摘Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non-linear but increasing relations of both geo-temperatures and geothermal gradients with increases depth. Numerically, we fitted the relationship between geo-temperatures and depth, a first-order exponential decay curve, formulated as: T(h) = 4.975 + 23.08 exp(h/1736.1).
文摘Thailand rice husk ash was used to synthesize zeolite by hydrothermal treatment. Raw rice husk ash material and zeolitic products were characterized in terms of specific surface area （BET method）, morphological analysis （SEM）, mineralogical composition （XRD） and CEC （cation exchange capacity）. LOI （Loss of ignition） of rice husk ash was also evaluated. Result indicated that the rice husk ash sample from Roi-Et Green power plant in the Northeastern of Thailand with combustion temperature of 650 ℃ has a high content of SiO2 （above 90 wt.%）. Zeolite-X from rice husk ash with high content of Si was successfully synthesized using hydrothermal treatment. The zeolitic material synthesized with the optimal condition possessed a maximum value of CEC of 503 meq/100g, and it has potentiality to be used as ion exchangers.
基金Funded by Chongqing Postdoctoral Science Foundation (No.XM2012002)the Fundamental Research Funds for the Central Universities (No.CQDXWL-2012-024)
文摘A novel metal（II）-organic complex Co（HIMP）（1,4-bdc）＇3H20 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffxaction. The complex is a mononuclear Co（II） complex, which is assembled into a 3D supramolecular architecture via strong intermolecular π…π stacking interactions and hydrogen bonds.
基金Supported by Applied Basic Research Project of Sichuan Province (No.2006J13-014)Innovation Fund of Panzhihua University
文摘In order to obtain anatase TiO2/expanded graphite with high expansion volume, titania gel was introduced to expandable graphite surface by sol-gel process, and then the composite was expanded and calcined at high tempera- ture. The samples were analysed by using scanning electron microscope （SEM）, X-ray diffraction（XRD）, energy disperse spectroscopy （EDS）, and differential scanning calorimetry （DSC）. The optimal conditions for preparation are as follows： the molar ratio of tetrabutyl orthotitanate to triethanolamine is 1 ： 0.4, and the calcination and expansion temperature is in the range of 650--750 ~C. Under such conditions, the expansion volume of composites could reach 98 mE/g, and the mass loss ratio is less than 5%. The analysis shows that lower temperature and smaller particle size of graphite are helpful to the formation of anatase-type of TiO2, but larger particle size will lead to lower mass loss ratio, and higher temperature and larger particle size will lead to higher expansion volume.
文摘Hydroxyl radicals, superoxide anions and nitricoxide radicals are reactive species that can attack biomolecules such as DNA, lipids and proteins to cause many lifestyle-related diseases including hypertension and photoaging. This study reports the synthesis of new copper-pyridoxine and iron-pyridoxine complexes. The complexes have been synthesized and characterized by molar conductances, IR, UV-Visible, mass spectrometry, melting points and magnetic moment datas. The molecular formula of the complex is found to be Fe（py ^-）2Cl.H2O. The pyH/pyligand is coordinated to copper and iron through N atom of the pyridine ring and O atom of 5＇-CH2OH group. The Fe（III） complex is found to be paramagnetic with one unpaired electron. The antioxidant activities of the free ligand and its complexes were determined in vitro.
文摘Residual stress continues to be important issues in shipbuilding. This paper demonstrates how the heat affected zone that results from welding could be identified nondestructively using MBN （magnetic Barkhausen noise） technique. A stress concentration region was created by placing a weld bead on a marine steel plate used in ship construction. MBN measurements were made on the back surface of the welded plate along the weld direction and perpendicular to it in a line that crosses the weld bead. The stress distribution as deduced from the MBN measurements was found to be anisotropic in the material of the heat affected zone. The heat induced anisotropy was completely eliminated by shot peening the HAZ material as revealed by MBN intensity. It was concluded that the directional MBN measurements could be used to characterize the induced anisotropy and hence assess the thermal residual stresses distribution near a localized stresses concentration regions imposed by welding.
