The Pt/C catalyst was prepared with solid phase reaction method (Pt/C(S)) for the first time. Its performances were compared with that prepared by the traditional liquid phase reaction method. The results demonstrate ...The Pt/C catalyst was prepared with solid phase reaction method (Pt/C(S)) for the first time. Its performances were compared with that prepared by the traditional liquid phase reaction method. The results demonstrate that the electrocatalytic activity of Pt/C catalyst with solid phase reaction method for methanol oxidation is higher than that with liquid phase reaction method. XRD and TEM measurements indicate that the Pt/C(S) possesses low crystalline extent and small particle size.展开更多
Manganese silicide MnSi2-x thin films have been prepared on n-type silicon substrates through solid phase reaction. The heterostructures were analyzed by X-ray diffraction, Rutherford backscattering spectroscopy, Four...Manganese silicide MnSi2-x thin films have been prepared on n-type silicon substrates through solid phase reaction. The heterostructures were analyzed by X-ray diffraction, Rutherford backscattering spectroscopy, Fourier transform infrared transmittance spectroscopy and the four-point probe technique. The results show that two manganese silicides have been formed sequentially via the reaction of thin layer Mn with Si substrate at different irradiation annealing stages, i.e., MnSi at 450℃ and MnSi1.73 at 550℃. MnSi1.73 phase exhibits preferred growth after irradiation with infrared. In situ four-point probe measurements of sheet resistance during infrared irradiation annealing show that nucleation of MnSi and phase transformation of MnSi to MnS1.73 occur at 410℃ and 530℃, respectively; the MnSi phase shows metallic behavior, while MnSi1.73 exhibits semiconducting behavior. Characteristic phonon bands of MnSi2-x suicides, which can be used for phase identification along with conventional XRD techniques, have been observed by FTIR spectroscopy.展开更多
A single crystalline Mg2 Si film was formed by solid phase reaction(SPR) of a Si(111) substrate with an Mg overlayer capped with an oxide layer(s),which was enhanced by post annealing from room temperature to 100 ℃in...A single crystalline Mg2 Si film was formed by solid phase reaction(SPR) of a Si(111) substrate with an Mg overlayer capped with an oxide layer(s),which was enhanced by post annealing from room temperature to 100 ℃in a molecular beam epitaxy(MBE) system.The thermal stability of the Mg2 Si film was then systematically investigated by post annealing in an oxygen-radical ambient at 300℃,450℃ and 650 ℃,respectively.The Mg2 Si film stayed stable until the annealing temperature reached 450 ℃ then it transformed into amorphous MgO x attributed to the decomposition of Mg2 Si and the oxidization of dissociated Mg.展开更多
The solid-phase reaction of sapphire (Al2O3) substrates and spin-coated copper nitrate films was studied. X-ray diffraction analysis revealed that a CuO fraction was observed by annealing at temperatures higher than ...The solid-phase reaction of sapphire (Al2O3) substrates and spin-coated copper nitrate films was studied. X-ray diffraction analysis revealed that a CuO fraction was observed by annealing at temperatures higher than 800℃. In addition, crystalline CuAlO2 was formed at annealing temperatures in the range of 900℃ – 1000℃ by solid-phase reaction of the spin-coated films and sapphire substrate. Crystalline CuAlO2 was formed by annealing at 1000℃ for 5 - 10 h, and CuAl2O4 was formed by annealing at 1000℃ for 15 h. When annealing under N2 flow, Cu2O was observed rather than CuAlO2. For a sample annealed in air at 1000℃ for 5 h, X-ray photoelectron spectroscopy measurements at various depths from surface revealed that Cu2+ ions are located around the surface, which suggests that the CuO fraction is present near the surface while the CuAlO2 fraction is located at greater depths from the surface of the samples. The depth profile of the sample suggests that there is no pure CuAlO2 layer in the sample, but that crystalline CuAlO2 is present in the sample as a mixture with CuO and Al2O3.展开更多
M, a particular industrial waste, was selected to detoxify chromium slag at a high temperature. The carbon remaining in M reduced Cr （Ⅵ） of Na2CrO4 borne in the chromium slag to Cr （Ⅲ） in the solid phase reactio...M, a particular industrial waste, was selected to detoxify chromium slag at a high temperature. The carbon remaining in M reduced Cr （Ⅵ） of Na2CrO4 borne in the chromium slag to Cr （Ⅲ） in the solid phase reaction, and its thermodynamics and kinetics were studied. The reduction process of Na2CrO4 by carbon produced CO, which was endothermic. Under the experimental condition, the apparent activation energy was 4.41 kJ·mol -1 , the apparent order of reaction for Na2CrO4 was equal to one, and the partial pressure of CO was only 0.22 Pa at 1 330 ℃.展开更多
Peptide nucleic acids (PNA) oligomers were synthesized in most cases by peptide synthesis from N-protected monomers. In this work a new method of obtaining PNA monomer by Ugi four-component condensation reaction was t...Peptide nucleic acids (PNA) oligomers were synthesized in most cases by peptide synthesis from N-protected monomers. In this work a new method of obtaining PNA monomer by Ugi four-component condensation reaction was tested by solid-phase synthesis. The Fmoc protected PNA monomer was build up with thymin-1-yl acetic acid, 3-methylbutyl aldehyde, Fmoc protected aminoethyl isocyanide and Gly-Wang resin.展开更多
We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylati...We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylation reaction and selenoxide syn-elimination, which ensures the purity of the products.展开更多
The nanosized zirconia was synthesized via solid state reaction in the presence of surfactant. The results indicate that crystal phase of zirconia can be controlled by tuning the syn- thesis parameters such as OH–/Zr...The nanosized zirconia was synthesized via solid state reaction in the presence of surfactant. The results indicate that crystal phase of zirconia can be controlled by tuning the syn- thesis parameters such as OH–/Zr molar ratio, crystallizing temperature and time. It can be trans- formed among amorphous, tetragonal and monoclinic phases. The transformation is driven by particle size. The research shows the nanocrystalline zirconia possesses the higher thermal stability compared with amorphous framework. The “glow exotherm” can be observed for the amorphous samples. Otherwise, it is in the absence for nanocrystalline samples. Herein, the reason for retention of tetragonal zirconia is demonstrated.展开更多
Offwhite pure Fe_2P_2O_7 was synthesized through solid phase reaction using Fe_2O_3 and NH_4H_2PO_4 in argon atmosphere.The reaction products of Fe_2O_3 and NH4_H_2PO_4 at a series of temperatures from 400 to 900℃wer...Offwhite pure Fe_2P_2O_7 was synthesized through solid phase reaction using Fe_2O_3 and NH_4H_2PO_4 in argon atmosphere.The reaction products of Fe_2O_3 and NH4_H_2PO_4 at a series of temperatures from 400 to 900℃were characterized by XRD.Comparison and analysis of XRD patterns of resultant products indicated well-crystallized Fe_2P_2O_7 could be obtained over 630℃and Fe_2P_2O_7 prepared at 700℃was triclinic in cell type.Comparison of the cell parameters proved that the as-prepared Fe_2P_2O_7 belonged toβ- Fe_2P_2O_7 in crystal phase and SEM showed its size distribution was 0.5-2μm.展开更多
The solid state reduction reaction of Al-10 % CuO mixed powders during mechanical alloying was investigated using XRD, DTA and TEM. The CuO is believed to be gradually reduced by Al, and controlled by diffusion of ato...The solid state reduction reaction of Al-10 % CuO mixed powders during mechanical alloying was investigated using XRD, DTA and TEM. The CuO is believed to be gradually reduced by Al, and controlled by diffusion of atoms and ions. Reduced Cu spontaneously reacts with Al to form a metastable equilibrium of Al (Cu) with Al4Cu9 phase during ball-milling, instead of CuAl2 and Al(Cu), which is only observed after annealing.展开更多
On an example of spontaneous changes 5,7-di-tert-butylspiro (2,5) octa-4,7-diene-6-one at room temperature, a new example of condensations in a solid station is opened. The single crystal of 2-(3’, 5'-di-tert-but...On an example of spontaneous changes 5,7-di-tert-butylspiro (2,5) octa-4,7-diene-6-one at room temperature, a new example of condensations in a solid station is opened. The single crystal of 2-(3’, 5'-di-tert-butyl-4'-hydroxy-phenyl)-ethyloxy-p-cresole is produced as result of a structure transformation 5,7-di-tert-butylspiro (2,5) octa-4,7-diene-6-one in a solid phase at room temperature except a single crystal at transformation 5,7-di-tert-butylspiro (2,5) octa-4,7-diene-6-one a new substance is formed too. Spectrums 1Н and 13С NMR differ from similar spectrums of initial compound and the single crystal. New substance represents an admixture of isomeric compounds, capable reversible to be transformed in initial 5,7-di-tert-butylspiro(2,5) octa-4,7-diene-6-one and 2-(3’, 5'-di-tert-butyl-4'-hydroxyphenyl)-ethyloxy-p-cresole.展开更多
基金The authors are grateful for the financial support of "973" Project(G2000026408)the National Natural Science Foundation of China(20003005)+1 种基金the Natural Science Foundation of Jiangsu Province(BQ2000009)the Natural Science Foundation of Jilin Province(20000510)
文摘The Pt/C catalyst was prepared with solid phase reaction method (Pt/C(S)) for the first time. Its performances were compared with that prepared by the traditional liquid phase reaction method. The results demonstrate that the electrocatalytic activity of Pt/C catalyst with solid phase reaction method for methanol oxidation is higher than that with liquid phase reaction method. XRD and TEM measurements indicate that the Pt/C(S) possesses low crystalline extent and small particle size.
基金This work has been supported jointly by the National Natural Science Foundation ofChina (Crant No. 69806005)the Natural Scie
文摘Manganese silicide MnSi2-x thin films have been prepared on n-type silicon substrates through solid phase reaction. The heterostructures were analyzed by X-ray diffraction, Rutherford backscattering spectroscopy, Fourier transform infrared transmittance spectroscopy and the four-point probe technique. The results show that two manganese silicides have been formed sequentially via the reaction of thin layer Mn with Si substrate at different irradiation annealing stages, i.e., MnSi at 450℃ and MnSi1.73 at 550℃. MnSi1.73 phase exhibits preferred growth after irradiation with infrared. In situ four-point probe measurements of sheet resistance during infrared irradiation annealing show that nucleation of MnSi and phase transformation of MnSi to MnS1.73 occur at 410℃ and 530℃, respectively; the MnSi phase shows metallic behavior, while MnSi1.73 exhibits semiconducting behavior. Characteristic phonon bands of MnSi2-x suicides, which can be used for phase identification along with conventional XRD techniques, have been observed by FTIR spectroscopy.
基金Project supported by the National Natural Science Foundation (Grant Nos 50532090,60606023 and 60621091)the Ministry of Science and Technology of China (Grant Nos 2002CB613502 and 2007CB936203)Australia Research Council
文摘A single crystalline Mg2 Si film was formed by solid phase reaction(SPR) of a Si(111) substrate with an Mg overlayer capped with an oxide layer(s),which was enhanced by post annealing from room temperature to 100 ℃in a molecular beam epitaxy(MBE) system.The thermal stability of the Mg2 Si film was then systematically investigated by post annealing in an oxygen-radical ambient at 300℃,450℃ and 650 ℃,respectively.The Mg2 Si film stayed stable until the annealing temperature reached 450 ℃ then it transformed into amorphous MgO x attributed to the decomposition of Mg2 Si and the oxidization of dissociated Mg.
文摘The solid-phase reaction of sapphire (Al2O3) substrates and spin-coated copper nitrate films was studied. X-ray diffraction analysis revealed that a CuO fraction was observed by annealing at temperatures higher than 800℃. In addition, crystalline CuAlO2 was formed at annealing temperatures in the range of 900℃ – 1000℃ by solid-phase reaction of the spin-coated films and sapphire substrate. Crystalline CuAlO2 was formed by annealing at 1000℃ for 5 - 10 h, and CuAl2O4 was formed by annealing at 1000℃ for 15 h. When annealing under N2 flow, Cu2O was observed rather than CuAlO2. For a sample annealed in air at 1000℃ for 5 h, X-ray photoelectron spectroscopy measurements at various depths from surface revealed that Cu2+ ions are located around the surface, which suggests that the CuO fraction is present near the surface while the CuAlO2 fraction is located at greater depths from the surface of the samples. The depth profile of the sample suggests that there is no pure CuAlO2 layer in the sample, but that crystalline CuAlO2 is present in the sample as a mixture with CuO and Al2O3.
基金Item Sponsored by National Natural Science Foundation of China (50234040)
文摘M, a particular industrial waste, was selected to detoxify chromium slag at a high temperature. The carbon remaining in M reduced Cr （Ⅵ） of Na2CrO4 borne in the chromium slag to Cr （Ⅲ） in the solid phase reaction, and its thermodynamics and kinetics were studied. The reduction process of Na2CrO4 by carbon produced CO, which was endothermic. Under the experimental condition, the apparent activation energy was 4.41 kJ·mol -1 , the apparent order of reaction for Na2CrO4 was equal to one, and the partial pressure of CO was only 0.22 Pa at 1 330 ℃.
基金This work was supposed by the National Basic Research Program(973 Program)from the Ministry of Science and Technology of China(G1998051114)the National Natural Science Foundation of China(20272004)
文摘Peptide nucleic acids (PNA) oligomers were synthesized in most cases by peptide synthesis from N-protected monomers. In this work a new method of obtaining PNA monomer by Ugi four-component condensation reaction was tested by solid-phase synthesis. The Fmoc protected PNA monomer was build up with thymin-1-yl acetic acid, 3-methylbutyl aldehyde, Fmoc protected aminoethyl isocyanide and Gly-Wang resin.
基金the National Natural Science Foundation of China(No.20332060)the Natural Science Foundation of Zhejiang Province(No.Y405407).
文摘We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylation reaction and selenoxide syn-elimination, which ensures the purity of the products.
文摘The nanosized zirconia was synthesized via solid state reaction in the presence of surfactant. The results indicate that crystal phase of zirconia can be controlled by tuning the syn- thesis parameters such as OH–/Zr molar ratio, crystallizing temperature and time. It can be trans- formed among amorphous, tetragonal and monoclinic phases. The transformation is driven by particle size. The research shows the nanocrystalline zirconia possesses the higher thermal stability compared with amorphous framework. The “glow exotherm” can be observed for the amorphous samples. Otherwise, it is in the absence for nanocrystalline samples. Herein, the reason for retention of tetragonal zirconia is demonstrated.
文摘Offwhite pure Fe_2P_2O_7 was synthesized through solid phase reaction using Fe_2O_3 and NH_4H_2PO_4 in argon atmosphere.The reaction products of Fe_2O_3 and NH4_H_2PO_4 at a series of temperatures from 400 to 900℃were characterized by XRD.Comparison and analysis of XRD patterns of resultant products indicated well-crystallized Fe_2P_2O_7 could be obtained over 630℃and Fe_2P_2O_7 prepared at 700℃was triclinic in cell type.Comparison of the cell parameters proved that the as-prepared Fe_2P_2O_7 belonged toβ- Fe_2P_2O_7 in crystal phase and SEM showed its size distribution was 0.5-2μm.
文摘The solid state reduction reaction of Al-10 % CuO mixed powders during mechanical alloying was investigated using XRD, DTA and TEM. The CuO is believed to be gradually reduced by Al, and controlled by diffusion of atoms and ions. Reduced Cu spontaneously reacts with Al to form a metastable equilibrium of Al (Cu) with Al4Cu9 phase during ball-milling, instead of CuAl2 and Al(Cu), which is only observed after annealing.
文摘On an example of spontaneous changes 5,7-di-tert-butylspiro (2,5) octa-4,7-diene-6-one at room temperature, a new example of condensations in a solid station is opened. The single crystal of 2-(3’, 5'-di-tert-butyl-4'-hydroxy-phenyl)-ethyloxy-p-cresole is produced as result of a structure transformation 5,7-di-tert-butylspiro (2,5) octa-4,7-diene-6-one in a solid phase at room temperature except a single crystal at transformation 5,7-di-tert-butylspiro (2,5) octa-4,7-diene-6-one a new substance is formed too. Spectrums 1Н and 13С NMR differ from similar spectrums of initial compound and the single crystal. New substance represents an admixture of isomeric compounds, capable reversible to be transformed in initial 5,7-di-tert-butylspiro(2,5) octa-4,7-diene-6-one and 2-(3’, 5'-di-tert-butyl-4'-hydroxyphenyl)-ethyloxy-p-cresole.
