Zeolites ZSM-5 with different Si/Al ratios were in-situ synthesized on the surface ofhoneycomb-shaped cordierite support for the first time. Characterizations of XRD and SEM wereperformed and it has been proved that t...Zeolites ZSM-5 with different Si/Al ratios were in-situ synthesized on the surface ofhoneycomb-shaped cordierite support for the first time. Characterizations of XRD and SEM wereperformed and it has been proved that the zeolite ZSM-5 was grown on the surface of the cordieritehomogeneously. NO decomposition on the Cu exchanged ZSM-5/cordierite monolith catalysts wasalso studied. It was found that the monolith catalysts have a fine initial activity at 673K and GHSVof 10,000h-1. Such method should be a good way to make auto exhaust converter with monolithcatalyst for NOx removal.展开更多
A new energetic organic potassium salt bis(dinitromethyl)difurazanyl ether potas- sium salt [K2(BDFE)] was synthesized, and structurally characterized by elemental analysis, IR spectra, t3C NMR and single-crystal ...A new energetic organic potassium salt bis(dinitromethyl)difurazanyl ether potas- sium salt [K2(BDFE)] was synthesized, and structurally characterized by elemental analysis, IR spectra, t3C NMR and single-crystal X-ray diffraction. K2(BDFE) crystallizes in monoclinic system, space group C2/c with a = 17.342(3), b = 12.6943(17), c = 8.0972(11) A, β = 110.630(2)°, V = 1668.3(4) A3, Z = 4, Dc = 2.000 g/cm3, F(000) = 1000,μ= 0.675 mm-1, S = 1.058, the final R = 0.0499 and wR = 0.1452. The K ion is eight-coordinated with eight O atoms from one water molecule and four bis(dinitromethyl)difurazanyl ethers (BDFE), forming a distorted dodecahedral structure. Thermal decomposition of the title complex was studied by using DSC and TG-DTG. There are primarily two exothermic decomposition processes between 200 and 370 ℃.展开更多
The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate (CTriMATT) were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, ...The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate (CTriMATT) were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Ultraviolet visible (UV-Vis) spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis (TG), differential thermal analysis (DTA) and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption (BET) and scanning electron microscopy (SEM). The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.展开更多
Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu,Zn)-ammonia complexes (DMAC) at various temperatures.The catalysts were characterized in d...Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu,Zn)-ammonia complexes (DMAC) at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol (212 g/(Lcat·h);T=513 K,p=3MPa,SV=12000 h-1).展开更多
Perovskite-type La0.8Sr0.2MnO3 was prepared by stearic acid gel combustion method.The obtained powders were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scaning electron micro...Perovskite-type La0.8Sr0.2MnO3 was prepared by stearic acid gel combustion method.The obtained powders were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scaning electron micrograph(SEM)and X-ray photoelectron spectroscopy(XPS)techniques.The catalytic activity of La0.8Sr0.2MnO3 was investigated on thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)by thermal gravity-differential scanning calorimetry(TG-DSC)techniques.The experimental results show that La0.8Sr0.2MnO3 is an effective catalyst for HMX thermal decomposition.The surface-adsorbed species such as H2O,OH - and adsorbed oxygen(Oad)could result in an advance in the onset temperature of HMX thermal decomposition.The mixture system of Mn 3+ and Mn 4+ ions and lattice oxygen could play key roles for the increase of the decomposition heat of HMX because these exothermic reactions could be catalyzed by La0.8Sr0.2MnO3 between CO and NOx(from the thermal decomposition of HMX)and the oxidation reaction of CO.According to the previous researches and our results,perovskite-type La0.8Sr0.2MnO3 may be used as a novel catalyst or modifier for nitrate ester plasticized polyether(NEPE)propellant.展开更多
The rare earth metal benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR and X-ray powder diffraction. They can be represented by general formula RE (C6H5...The rare earth metal benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR and X-ray powder diffraction. They can be represented by general formula RE (C6H5COO)(3)(RE = La, Nd, Sm, Eu, Gd, Dy and Er). All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth metal benzoates was studied by using TG, DTA, IR, and gas chromatography-mass spectrometry. The thermal decomposition of the rare earth benzoates in nitrogen proceeded in two stages; firstly it decomposed to form RE2O(CO3)(2) and organic compounds, then RE2O(CO3)(2) decomposed further to form rare earth metal oxides and carbon dioxide. The organic compounds obtained from the first step of the reaction are mainly benzophenone, 9,10-anthraquinone, 1, 3-Diphenylisobenzofuran and so on.展开更多
Highly dispersed perovskite NdCoO3 nanoparticles were prepared by a novel salt-assisted combustion process. The effects of NaCl content and calcination temperature on the characteristics of the products were character...Highly dispersed perovskite NdCoO3 nanoparticles were prepared by a novel salt-assisted combustion process. The effects of NaCl content and calcination temperature on the characteristics of the products were characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and BET surface area measurement. The facile introduction of NaCl in the conventional combustion synthesis process was found to result in the formation of well-dispersed perovskite nanoparticles and increase specific surface areas of the resultants from 1.7 to 43.2 m2·g-1. The catalytic properties of the typical NdCoO3 samples for thermal decomposition of ammonia perchlorate (AP) and their correlation with the NdCoO3 microstructure were investigated by Differential Scanning Calorimetry (DSC). The DSC results indicate that the addition of the amorphous NdCoO3 nanoparticles to AP incorporates two small exothermic peaks of AP into a strong exothermic peak, decreases the temperature of the AP exothermic peak to 314.0 ℃ by reduction of 138.3 ℃ and increases the apparent decomposition heat from 515 J·g-1 to over 1441 J·g-1, showing the intense catalytic activity for thermal decomposition of AP. It is also clear that the catalytic activity of the resultant NdCoO3 is related to their microstructure. According to Kissinger′s method, the kinetics parameters of the thermal decomposition of AP catalyzed by the as-prepared NdCoO3 samples were calculated to account for the order of their catalytic activity.展开更多
The effect of calcination condition on the cobalt species and Fischer-Tropsch synthesis (FTS) was studied. It was found that higher calcination temperature resulted in decreased FTS activities because CNTs were cons...The effect of calcination condition on the cobalt species and Fischer-Tropsch synthesis (FTS) was studied. It was found that higher calcination temperature resulted in decreased FTS activities because CNTs were consumed by oxidation in air at temperature higher than 230 ℃. Cobalt species went through transformation from Co304 to metallic Co in Ar by autoreduction at temperature over 500℃. The autoreduction route might be Co3O4→CoO→C0 or Co3O4→Co2C→Co. Reduction at temperature higher than 500 ℃ also resulted in decreased FTS activities due to the methanation of CNTs in hydrogen.展开更多
The paper reports the synthetic procedure and character of Copper(II) binuclearcoordination compound of 1,4-bis-(1'-phenyl-3'-methyl-5'-pyrazolone Thenon-isothermal kinetics of thermal decomposition of the...The paper reports the synthetic procedure and character of Copper(II) binuclearcoordination compound of 1,4-bis-(1'-phenyl-3'-methyl-5'-pyrazolone Thenon-isothermal kinetics of thermal decomposition of the complex has been stUdied from the TG-DTGcurves by means of the Achar et al. and Coats-Redfern methods,the most probab1e kinetic equation canbe expressed as dofdtrAe -E / RT * l /(2Q).The corresponding kinetic compensation effect expressions arefound to be lnuA=0. 1794E+0. 1689.The non-isothermal thermal decomposition process of the complex isone-dimensional diffusion.But electrochemical studies of the complex(Cu2L'2)from cyclic voltamrnetriccurves by means of powder microelectrodes technique'',shows one two-electron irreversible process.展开更多
Dry reforming of methane by CO2 using nickel ferrite as precursor of catalysts was investigated.Nickel ferrite crystalline particles were prepared by coprecipitation of nitrates with NaOH or ammonia followed by calcin...Dry reforming of methane by CO2 using nickel ferrite as precursor of catalysts was investigated.Nickel ferrite crystalline particles were prepared by coprecipitation of nitrates with NaOH or ammonia followed by calcination,or by hydrothermal synthesis without calcination step.The textural and structural properties were determined by a number of analysis methods,including X-ray diffraction (XRD),Raman spectroscopy and X-ray photoelectron spectroscopy (XPS),among which X-ray diffraction (XRD) was at room and variable temperatures.All synthesized oxides showed the presence of micro or nanoparticles of NiFe2O4 inverse spinel,but Fe2O3 (hematite) was also present when ammonia was used for coprecipitation.The reducibility by hydrogen was studied by temperature-programmed reduction (TPR) and in situ XRD,which showed the influence of the preparation method.The surface area (BET),particle size (Rietveld refinement),as well as surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied according to the synthesis method.The catalytic reactivity was investigated using isopropanol decomposition to determine the acid/base properties.The catalytic performance of methane reforming with CO2 was measured with and without the pre-treatment of catalysts under H2 in 650-800 C range.The catalytic conversions of methane and CO2 were quite low but they increased when the catalysts were pre-reduced.A significant contribution of reverse water gas shift reaction accounted for the low values of H2 /CO ratio.No coking was observed as shown by the reoxidation step performed after the catalytic reactions.The possible formation of nickel-iron alloy observed during the study of reducibility by hydrogen was invoked to account for the catalytic behavior.展开更多
A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide(Ⅲ) chloride to form complexes of the type [Ln(HISA)2Cl3], where, Ln=La(Ⅲ), Ce(Ⅲ), Pr(Ⅲ), Nd(...A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide(Ⅲ) chloride to form complexes of the type [Ln(HISA)2Cl3], where, Ln=La(Ⅲ), Ce(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), Sm(Ⅲ), Eu(Ⅲ), or Gd(Ⅲ) and HISA= [(2-hydroxybenzaldehyde)-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum(Ⅲ) complex were subjected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum(Ⅲ) complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La(HISA)2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.展开更多
Non-porous carbon sphere was used as support to synthesize supported cobalt Fischer-Tropsch catalysts with high activity and durability. Strong metal-support interaction was avoided and intrinsic activity of pristine ...Non-porous carbon sphere was used as support to synthesize supported cobalt Fischer-Tropsch catalysts with high activity and durability. Strong metal-support interaction was avoided and intrinsic activity of pristine cobalt nano-particles was studied. Thermal decomposition synthesis method was applied to obtain cobalt catalysts with high dispersion and narrow particle size distribution. Furthermore the cobalt size can be controlled by the molar ratio of o-dichlorobenzene/benzylamine. Compared with supported cobalt catalysts prepared by incipient wetness impregnation method and ultrasonic impregnation method,the catalyst prepared by thermal decomposition method showed higher catalytic activity, higher long chain hydrocarbons selectivity and lower methane selectivity.展开更多
The method of empirical mode decomposition(EMD) was used for the signal processing and featureing of acoustic target of battle field. According to the signal's characteristics of different targets, some feature ve...The method of empirical mode decomposition(EMD) was used for the signal processing and featureing of acoustic target of battle field. According to the signal's characteristics of different targets, some feature vectors in token of the target properties were constructed and abstracted. In the basis of feature abstracting and statistic analysis for large amount of sample signal of the targets, using the maximum subjection classification method based on the fuzzy synthesis judgment, the three typical acoustic target helicopter, tank and traffic vehicle were recognized.展开更多
In some satellite communications, we need to perform Direction Of Arrival (DOA) angle estima- tion under the restriction that the number of receivers is less than that of the array elements in an array antenna. To sol...In some satellite communications, we need to perform Direction Of Arrival (DOA) angle estima- tion under the restriction that the number of receivers is less than that of the array elements in an array antenna. To solve the conundrum, a method named subarray-synthesis-based Two-Dimensional DOA (2D DOA) angle estimation is proposed. In the method, firstly, the array antenna is divided into a series of subarray antennas based on the total number of receivers; secondly, the subarray antennas’ output covariance matrices are esti- mated; thirdly, an equivalent covariance matrix is synthesized based on the subarray output covariance matri- ces; then 2D DOA estimation is performed. Monte Carlo simulations showed that the estimation method is ef- fective.展开更多
文摘Zeolites ZSM-5 with different Si/Al ratios were in-situ synthesized on the surface ofhoneycomb-shaped cordierite support for the first time. Characterizations of XRD and SEM wereperformed and it has been proved that the zeolite ZSM-5 was grown on the surface of the cordieritehomogeneously. NO decomposition on the Cu exchanged ZSM-5/cordierite monolith catalysts wasalso studied. It was found that the monolith catalysts have a fine initial activity at 673K and GHSVof 10,000h-1. Such method should be a good way to make auto exhaust converter with monolithcatalyst for NOx removal.
基金supported by the National Natural Science Foundation of China(No.21243007)National Defense Fundamental Scientific Research(No.B09201100051)
文摘A new energetic organic potassium salt bis(dinitromethyl)difurazanyl ether potas- sium salt [K2(BDFE)] was synthesized, and structurally characterized by elemental analysis, IR spectra, t3C NMR and single-crystal X-ray diffraction. K2(BDFE) crystallizes in monoclinic system, space group C2/c with a = 17.342(3), b = 12.6943(17), c = 8.0972(11) A, β = 110.630(2)°, V = 1668.3(4) A3, Z = 4, Dc = 2.000 g/cm3, F(000) = 1000,μ= 0.675 mm-1, S = 1.058, the final R = 0.0499 and wR = 0.1452. The K ion is eight-coordinated with eight O atoms from one water molecule and four bis(dinitromethyl)difurazanyl ethers (BDFE), forming a distorted dodecahedral structure. Thermal decomposition of the title complex was studied by using DSC and TG-DTG. There are primarily two exothermic decomposition processes between 200 and 370 ℃.
基金This work is sponsored by National Key Fundamental Research Development Plan ("973" Plan, No.2004CB217807)the China National Petroleum Corporation (No. B04A50502)
文摘The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate (CTriMATT) were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Ultraviolet visible (UV-Vis) spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis (TG), differential thermal analysis (DTA) and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption (BET) and scanning electron microscopy (SEM). The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.
基金supported by the National Basic Research Program of China (No. 2011CB201404)the financial support of the State Key Laboratory for Oxo Synthesis and Selective Oxidation (OSSO) of China
文摘Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu,Zn)-ammonia complexes (DMAC) at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol (212 g/(Lcat·h);T=513 K,p=3MPa,SV=12000 h-1).
基金Supported by the National Natural Science Foundation of China (20671084)
文摘Perovskite-type La0.8Sr0.2MnO3 was prepared by stearic acid gel combustion method.The obtained powders were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scaning electron micrograph(SEM)and X-ray photoelectron spectroscopy(XPS)techniques.The catalytic activity of La0.8Sr0.2MnO3 was investigated on thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)by thermal gravity-differential scanning calorimetry(TG-DSC)techniques.The experimental results show that La0.8Sr0.2MnO3 is an effective catalyst for HMX thermal decomposition.The surface-adsorbed species such as H2O,OH - and adsorbed oxygen(Oad)could result in an advance in the onset temperature of HMX thermal decomposition.The mixture system of Mn 3+ and Mn 4+ ions and lattice oxygen could play key roles for the increase of the decomposition heat of HMX because these exothermic reactions could be catalyzed by La0.8Sr0.2MnO3 between CO and NOx(from the thermal decomposition of HMX)and the oxidation reaction of CO.According to the previous researches and our results,perovskite-type La0.8Sr0.2MnO3 may be used as a novel catalyst or modifier for nitrate ester plasticized polyether(NEPE)propellant.
文摘The rare earth metal benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR and X-ray powder diffraction. They can be represented by general formula RE (C6H5COO)(3)(RE = La, Nd, Sm, Eu, Gd, Dy and Er). All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth metal benzoates was studied by using TG, DTA, IR, and gas chromatography-mass spectrometry. The thermal decomposition of the rare earth benzoates in nitrogen proceeded in two stages; firstly it decomposed to form RE2O(CO3)(2) and organic compounds, then RE2O(CO3)(2) decomposed further to form rare earth metal oxides and carbon dioxide. The organic compounds obtained from the first step of the reaction are mainly benzophenone, 9,10-anthraquinone, 1, 3-Diphenylisobenzofuran and so on.
基金the National Natural Science Foundation of China (50306008)Start up Research Fund of Nanchang University and the Natural Science Foundation of Higher Education Institutions in Anhui Province (KJ2007B231)
文摘Highly dispersed perovskite NdCoO3 nanoparticles were prepared by a novel salt-assisted combustion process. The effects of NaCl content and calcination temperature on the characteristics of the products were characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and BET surface area measurement. The facile introduction of NaCl in the conventional combustion synthesis process was found to result in the formation of well-dispersed perovskite nanoparticles and increase specific surface areas of the resultants from 1.7 to 43.2 m2·g-1. The catalytic properties of the typical NdCoO3 samples for thermal decomposition of ammonia perchlorate (AP) and their correlation with the NdCoO3 microstructure were investigated by Differential Scanning Calorimetry (DSC). The DSC results indicate that the addition of the amorphous NdCoO3 nanoparticles to AP incorporates two small exothermic peaks of AP into a strong exothermic peak, decreases the temperature of the AP exothermic peak to 314.0 ℃ by reduction of 138.3 ℃ and increases the apparent decomposition heat from 515 J·g-1 to over 1441 J·g-1, showing the intense catalytic activity for thermal decomposition of AP. It is also clear that the catalytic activity of the resultant NdCoO3 is related to their microstructure. According to Kissinger′s method, the kinetics parameters of the thermal decomposition of AP catalyzed by the as-prepared NdCoO3 samples were calculated to account for the order of their catalytic activity.
基金supported by the National Natural Science Foundation of China (21076151)New Century Excellent Talents in University Chinese Ministry of Education (NCET-06-0239)the Programme of Introducing Talents of Discipline to Universities (B06006)
文摘The effect of calcination condition on the cobalt species and Fischer-Tropsch synthesis (FTS) was studied. It was found that higher calcination temperature resulted in decreased FTS activities because CNTs were consumed by oxidation in air at temperature higher than 230 ℃. Cobalt species went through transformation from Co304 to metallic Co in Ar by autoreduction at temperature over 500℃. The autoreduction route might be Co3O4→CoO→C0 or Co3O4→Co2C→Co. Reduction at temperature higher than 500 ℃ also resulted in decreased FTS activities due to the methanation of CNTs in hydrogen.
文摘The paper reports the synthetic procedure and character of Copper(II) binuclearcoordination compound of 1,4-bis-(1'-phenyl-3'-methyl-5'-pyrazolone Thenon-isothermal kinetics of thermal decomposition of the complex has been stUdied from the TG-DTGcurves by means of the Achar et al. and Coats-Redfern methods,the most probab1e kinetic equation canbe expressed as dofdtrAe -E / RT * l /(2Q).The corresponding kinetic compensation effect expressions arefound to be lnuA=0. 1794E+0. 1689.The non-isothermal thermal decomposition process of the complex isone-dimensional diffusion.But electrochemical studies of the complex(Cu2L'2)from cyclic voltamrnetriccurves by means of powder microelectrodes technique'',shows one two-electron irreversible process.
文摘Dry reforming of methane by CO2 using nickel ferrite as precursor of catalysts was investigated.Nickel ferrite crystalline particles were prepared by coprecipitation of nitrates with NaOH or ammonia followed by calcination,or by hydrothermal synthesis without calcination step.The textural and structural properties were determined by a number of analysis methods,including X-ray diffraction (XRD),Raman spectroscopy and X-ray photoelectron spectroscopy (XPS),among which X-ray diffraction (XRD) was at room and variable temperatures.All synthesized oxides showed the presence of micro or nanoparticles of NiFe2O4 inverse spinel,but Fe2O3 (hematite) was also present when ammonia was used for coprecipitation.The reducibility by hydrogen was studied by temperature-programmed reduction (TPR) and in situ XRD,which showed the influence of the preparation method.The surface area (BET),particle size (Rietveld refinement),as well as surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied according to the synthesis method.The catalytic reactivity was investigated using isopropanol decomposition to determine the acid/base properties.The catalytic performance of methane reforming with CO2 was measured with and without the pre-treatment of catalysts under H2 in 650-800 C range.The catalytic conversions of methane and CO2 were quite low but they increased when the catalysts were pre-reduced.A significant contribution of reverse water gas shift reaction accounted for the low values of H2 /CO ratio.No coking was observed as shown by the reoxidation step performed after the catalytic reactions.The possible formation of nickel-iron alloy observed during the study of reducibility by hydrogen was invoked to account for the catalytic behavior.
文摘A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide(Ⅲ) chloride to form complexes of the type [Ln(HISA)2Cl3], where, Ln=La(Ⅲ), Ce(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), Sm(Ⅲ), Eu(Ⅲ), or Gd(Ⅲ) and HISA= [(2-hydroxybenzaldehyde)-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum(Ⅲ) complex were subjected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum(Ⅲ) complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La(HISA)2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.
基金supported by the Key Program project of the NSFC and China Petrochemical Corporation Joint Fund (Grant No. U1463210)the Natural Science Foundation of Hubei Province of China (2013CFA089)the Fundamental Research Funds for the Central Universities, South-Central University for Nationalities (CZZ13002 and CZW15099)
文摘Non-porous carbon sphere was used as support to synthesize supported cobalt Fischer-Tropsch catalysts with high activity and durability. Strong metal-support interaction was avoided and intrinsic activity of pristine cobalt nano-particles was studied. Thermal decomposition synthesis method was applied to obtain cobalt catalysts with high dispersion and narrow particle size distribution. Furthermore the cobalt size can be controlled by the molar ratio of o-dichlorobenzene/benzylamine. Compared with supported cobalt catalysts prepared by incipient wetness impregnation method and ultrasonic impregnation method,the catalyst prepared by thermal decomposition method showed higher catalytic activity, higher long chain hydrocarbons selectivity and lower methane selectivity.
文摘The method of empirical mode decomposition(EMD) was used for the signal processing and featureing of acoustic target of battle field. According to the signal's characteristics of different targets, some feature vectors in token of the target properties were constructed and abstracted. In the basis of feature abstracting and statistic analysis for large amount of sample signal of the targets, using the maximum subjection classification method based on the fuzzy synthesis judgment, the three typical acoustic target helicopter, tank and traffic vehicle were recognized.
基金Grant-in-Aid for the COE project (Giant Molecules and Complex Systems) Steel Industry Foundation for the Advancement of Environmental Protection Technology
基金Supported by the National Natural Science Foundation of China (No.60462002 and No.60302006).
文摘In some satellite communications, we need to perform Direction Of Arrival (DOA) angle estima- tion under the restriction that the number of receivers is less than that of the array elements in an array antenna. To solve the conundrum, a method named subarray-synthesis-based Two-Dimensional DOA (2D DOA) angle estimation is proposed. In the method, firstly, the array antenna is divided into a series of subarray antennas based on the total number of receivers; secondly, the subarray antennas’ output covariance matrices are esti- mated; thirdly, an equivalent covariance matrix is synthesized based on the subarray output covariance matri- ces; then 2D DOA estimation is performed. Monte Carlo simulations showed that the estimation method is ef- fective.