The electronic structure of iron-pnictide compound superconductor Ba_2Ti_2Fe_2As_4O, which has metallic intermediate Ti_2O layers, is studied using angle-resolved photoemission spectroscopy. The Ti-related bands show ...The electronic structure of iron-pnictide compound superconductor Ba_2Ti_2Fe_2As_4O, which has metallic intermediate Ti_2O layers, is studied using angle-resolved photoemission spectroscopy. The Ti-related bands show a‘peak-dip-hump＇ line shape with two branches of dispersion associated with the polaronic states at temperatures below around 120 K. This change in the spectra occurs along with the resistivity anomaly that was not clearly understood in a previous study. Moreover, an energy gap induced by the superconducting proximity effect opens in the polaronic bands at temperatures below T_c（~21 K）. Our study provides the spectroscopic evidence that superconductivity coexists with polarons in the same bands near the Fermi level, which provides a suitable platform to study interactions between charge, lattice and spin freedoms in a correlated system.展开更多
In-situ HVEM observation on phase transition of the YBa_2Cu_3O_(7-x) superconducting compound in pro- cess of heating was carried out,and high temperature X-ray diffraction analysis in air and X-ray diffraction phase ...In-situ HVEM observation on phase transition of the YBa_2Cu_3O_(7-x) superconducting compound in pro- cess of heating was carried out,and high temperature X-ray diffraction analysis in air and X-ray diffraction phase analysis for the sample treated in vacuum condition were made.The results showed that the temperature of phase transition is related to oxygen content in the sample and in general,is 100℃ to 120℃ lower in vacu- um condition than in air.At 320℃ to 350℃ twin bands begin to disappear,and some Cu_2O are formed on the surface of the sample and transit from orthorhombic YBa_2Cu_3O_(7-x) to arthorhombic Y_2BaCuO_5 compound. This transition was completed at about 500℃.Above 900℃,this compound consists of the Y_2BaCuO_5, BaCuO_2,Y_2O_3 and some other minor compounds.No phase transition was observed during cooling the sample.展开更多
A2B2O7 pyrochlore is a kind of important functional materials for different purposes,which has been investigated extensively by crystallographers and material scientists.However,the catalytic chemistry of this type of...A2B2O7 pyrochlore is a kind of important functional materials for different purposes,which has been investigated extensively by crystallographers and material scientists.However,the catalytic chemistry of this type of special compounds has rarely been documented,though a few researchers have tried to synthesize some pyrochlore compounds with different chemical compositions for a variety of green energy production and air pollution control reactions in the history.With the expectation to help catalysis scientists to get better acquaintance with,and gain deeper understanding on this type of compounds as heterogeneous catalysts,the major publications over the past several decades have been screened and reviewed in this paper,based also on our own experience of studying on this type of catalytic materials.The crystalline phase transformations of the compounds with the change of the A and B site cations,the phase change’s influences on the surface and bulk properties,and their subsequent impact on the catalytic performance for different reactions have been summarized.Furthermore,the future work which needs to be performed to perceive in depth this kind of important materials as catalysts has been proposed and suggested.We trust that this short review contains valuable information,which will provide great help for people to get better cognition for A2 B2 O7 pyrochlore compounds,and assist them to develop better catalysts for various reactions.展开更多
Michael addition of nitroalkanes to α,β-unsaturated carbonyl compounds occurs in the presence of KF/AI_2O_3/PEG4000 without solvent.Yields are fair to good and work-ups are easy.
A new compound Ba6Ti7Nb9O42 was prepared for the first time by solid state reaction in BaO-TiO2-Nb2O5, ternary system. The X-ray powder diffraction data of the title compound was determined. Ba6Ti7Nb9O42 crystallizes ...A new compound Ba6Ti7Nb9O42 was prepared for the first time by solid state reaction in BaO-TiO2-Nb2O5, ternary system. The X-ray powder diffraction data of the title compound was determined. Ba6Ti7Nb9O42 crystallizes in the hexagonal system -with unit cell parameters a=9.0527(4) A,c=11.790(1) A,and space group P63/mcm(193),z=1. The calculated and measured densities are 5. 293 g/cm3 and 5.285 g/cm3, respectively.展开更多
Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The...Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles. The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated. The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone, ether, methanol, ethanol, butanol and hexanol. Meanwhile, it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260 ℃. The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.展开更多
The cluster compound[Mo_4S_4(μ-O_2CC_5H_5)_2(dtp)_4](dtp=S_2P(OEt)_2)was obtained by the ligand substitution reaction of tetranuclear molybdenum cluster [Mo_4S_4(μ-dtp)_2(dtp)_4]in the mixed solvent of acetone,ethan...The cluster compound[Mo_4S_4(μ-O_2CC_5H_5)_2(dtp)_4](dtp=S_2P(OEt)_2)was obtained by the ligand substitution reaction of tetranuclear molybdenum cluster [Mo_4S_4(μ-dtp)_2(dtp)_4]in the mixed solvent of acetone,ethanol and water in the presence of C_6H_5CO_2Na.It is monoclinic and crystallizes in space group C2/c, Mr=1495.09,a=12.175(5),b=22.01(1),c=20.875(9),β=99.04(4)°;V=5575(5);Z=4; Dc=1.78g/cm^3.Final R factor is 0.066.The result reveals that the[Mo_4S_4]cluster core and t-(dtp)^(-1)ligands are retained and only μ-bridged(dtp)^(-1)ligands are substituted by(C_6H_5CO_2)^(-1)in the substitution reaction,thus producing the new title cluster compound,the structure of which contains two species of bidentate ligand.展开更多
Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds. The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identifie...Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds. The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identified as the benezenediazonium ion, the ultimate carcinogens, which could bind to DNA. The reaction conditions were investigated preliminarily. Some inhibitors and inducers of the reaction were discovered.展开更多
Mesoporous TiO2 ceramic films have been prepared upon the Ti alloy substrate by the micro-arc oxidation (MAO) technology. To enhance the photo-catalytic property of the films, Eu2O3 particles were added into the elect...Mesoporous TiO2 ceramic films have been prepared upon the Ti alloy substrate by the micro-arc oxidation (MAO) technology. To enhance the photo-catalytic property of the films, Eu2O3 particles were added into the electrolyte solution of Na2CO3/Na2SiO3. Scanning electron microscope (SEM), energy dispersive (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) are employed to characterize the modified films. Diffuse reflectance spectra (DRS) test, photo-generated current test and photo decomposition test are applied to evaluate the photo-catalytic property of the modified films. The results show that Eu2O3 transformed into one-dimensional (1-D) nano-wires embedded within the composite film, and the film has high photo-catalytic property.展开更多
n.m, n.Om, nO.m and nO.Om compounds play an important role in the fundamental and applied aspects. As a part of our systematic studies of the above homologous series regarding the synthesis, characterization and phase...n.m, n.Om, nO.m and nO.Om compounds play an important role in the fundamental and applied aspects. As a part of our systematic studies of the above homologous series regarding the synthesis, characterization and phase transition studies, here the authors report the polarizabilities and orientational order parameter, S in N-(p-n-ethoxybenzylidene)-p-n-alkoxy anilines, 2O.Om with m = 3 to 10 liquid crystalline compounds except with m = 5 which has been already published. The rest of the compounds exhibit the nematic LC phase except with m = 10 which shows the smectic-C phase along the nematic phase which is originally not detected by Godzwon et al. But the author’s observations with TM and differential scanning calorimeter have shown the existence on SmC phase in addition to nematic phase. Further, SmC is clarified using the histogram technique whose details are given below and are published elsewhere. The orientstonal order parameter, S is estimated using different methods and compared with the value obtained from birefringence, δn = (n<sub>e</sub> – n<sub>o</sub>) where no field model is used. It is observed in these compounds case as in other LC compounds Vuks isotropic model is favored compared to that of anisotropic model proposed by Neugebauer.展开更多
在 NCU PP技术沉积的 Ti N- Mo S2 / Ti N复合膜中添加 A1元素并改变部分沉积工艺 ,可以在 1Cr18Ni9Ti基体上沉积出 Ti Al N - Mo S2 / Ti Al N硬质润滑膜 .利用 SEM,XPS等手段研究涂层的成分、微观结构等 .通过摩擦学试验测定其结合强...在 NCU PP技术沉积的 Ti N- Mo S2 / Ti N复合膜中添加 A1元素并改变部分沉积工艺 ,可以在 1Cr18Ni9Ti基体上沉积出 Ti Al N - Mo S2 / Ti Al N硬质润滑膜 .利用 SEM,XPS等手段研究涂层的成分、微观结构等 .通过摩擦学试验测定其结合强度等性能 .结果表明 ,在钻头上沉积 Ti Al N- Mo S2 / Ti Al N硬质膜 ,可使其在钻削过程中具有优异的耐磨、减摩和耐高温等性能 。展开更多
A series of mixed oxide catalysts with different composition of Co-M-Al and Co-M-Ce- Al （M=Zn, Ni, Cu） were prepared by co-precipitation method from hydrotalcite-like compounds. The experimental results revealed the...A series of mixed oxide catalysts with different composition of Co-M-Al and Co-M-Ce- Al （M=Zn, Ni, Cu） were prepared by co-precipitation method from hydrotalcite-like compounds. The experimental results revealed the catalytic activity of Co-Ni-Al is slightly higher than that of Co-Zn-Al and much higher than that of Co-Cu-Al for direct decomposition of N2O. Moreover, addition of small amounts of Ce02 improved the catalytic activity signif- icantly and made the decomposition temperatures at which the N2O conversion was 50% and 90% （T50 and Tgo） both decreased 80 ℃ than those of Co-M-Al catalysts without CeO2 added. Further, potassium-load also promoted the catalytic activity, and the decomposi- tion temperatures of T50 and T90 both decreased approximately 50 ℃. It is significant for decomposing N2O from industries and reducing carbon emission from atmosphere.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB921700,2015CB921300 and2015CB921301the National Natural Science Foundation of China under Grant Nos 11234014,11622435,11274362,11674371 and11474340+1 种基金the National Key Research and Development Program of China under Grant Nos 2016YFA0300300,2016YFA0300600,2016YFA0401000 and 2016YFA0400902the Open Large Infrastructure Research of Chinese Academy of Sciences,and the Pioneer Hundred Talents Program(Type C)of Chinese Academy of Sciences
文摘The electronic structure of iron-pnictide compound superconductor Ba_2Ti_2Fe_2As_4O, which has metallic intermediate Ti_2O layers, is studied using angle-resolved photoemission spectroscopy. The Ti-related bands show a‘peak-dip-hump＇ line shape with two branches of dispersion associated with the polaronic states at temperatures below around 120 K. This change in the spectra occurs along with the resistivity anomaly that was not clearly understood in a previous study. Moreover, an energy gap induced by the superconducting proximity effect opens in the polaronic bands at temperatures below T_c（~21 K）. Our study provides the spectroscopic evidence that superconductivity coexists with polarons in the same bands near the Fermi level, which provides a suitable platform to study interactions between charge, lattice and spin freedoms in a correlated system.
文摘In-situ HVEM observation on phase transition of the YBa_2Cu_3O_(7-x) superconducting compound in pro- cess of heating was carried out,and high temperature X-ray diffraction analysis in air and X-ray diffraction phase analysis for the sample treated in vacuum condition were made.The results showed that the temperature of phase transition is related to oxygen content in the sample and in general,is 100℃ to 120℃ lower in vacu- um condition than in air.At 320℃ to 350℃ twin bands begin to disappear,and some Cu_2O are formed on the surface of the sample and transit from orthorhombic YBa_2Cu_3O_(7-x) to arthorhombic Y_2BaCuO_5 compound. This transition was completed at about 500℃.Above 900℃,this compound consists of the Y_2BaCuO_5, BaCuO_2,Y_2O_3 and some other minor compounds.No phase transition was observed during cooling the sample.
基金Project supported by the National Natural Science Foundation of China(21962009,21567016,21666020)Natural Science Foundation of Jiangxi Province(20181ACB20005,20171BAB213013,20181BAB203017)Key Laboratory Foundation of Jiangxi Province for Environment and Energy Catalysis(20181BCD40004)。
文摘A2B2O7 pyrochlore is a kind of important functional materials for different purposes,which has been investigated extensively by crystallographers and material scientists.However,the catalytic chemistry of this type of special compounds has rarely been documented,though a few researchers have tried to synthesize some pyrochlore compounds with different chemical compositions for a variety of green energy production and air pollution control reactions in the history.With the expectation to help catalysis scientists to get better acquaintance with,and gain deeper understanding on this type of compounds as heterogeneous catalysts,the major publications over the past several decades have been screened and reviewed in this paper,based also on our own experience of studying on this type of catalytic materials.The crystalline phase transformations of the compounds with the change of the A and B site cations,the phase change’s influences on the surface and bulk properties,and their subsequent impact on the catalytic performance for different reactions have been summarized.Furthermore,the future work which needs to be performed to perceive in depth this kind of important materials as catalysts has been proposed and suggested.We trust that this short review contains valuable information,which will provide great help for people to get better cognition for A2 B2 O7 pyrochlore compounds,and assist them to develop better catalysts for various reactions.
文摘Michael addition of nitroalkanes to α,β-unsaturated carbonyl compounds occurs in the presence of KF/AI_2O_3/PEG4000 without solvent.Yields are fair to good and work-ups are easy.
基金Fund by International Centre for diffraction Data.
文摘A new compound Ba6Ti7Nb9O42 was prepared for the first time by solid state reaction in BaO-TiO2-Nb2O5, ternary system. The X-ray powder diffraction data of the title compound was determined. Ba6Ti7Nb9O42 crystallizes in the hexagonal system -with unit cell parameters a=9.0527(4) A,c=11.790(1) A,and space group P63/mcm(193),z=1. The calculated and measured densities are 5. 293 g/cm3 and 5.285 g/cm3, respectively.
基金supported by the National Natural Science Foundation of China (No. 20871071)the Science and Technology Commission Foundation of Tianjin (Nos. 09JCYBJC03600 and 10JCYBJC03900)
文摘Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles. The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated. The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone, ether, methanol, ethanol, butanol and hexanol. Meanwhile, it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260 ℃. The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.
文摘The cluster compound[Mo_4S_4(μ-O_2CC_5H_5)_2(dtp)_4](dtp=S_2P(OEt)_2)was obtained by the ligand substitution reaction of tetranuclear molybdenum cluster [Mo_4S_4(μ-dtp)_2(dtp)_4]in the mixed solvent of acetone,ethanol and water in the presence of C_6H_5CO_2Na.It is monoclinic and crystallizes in space group C2/c, Mr=1495.09,a=12.175(5),b=22.01(1),c=20.875(9),β=99.04(4)°;V=5575(5);Z=4; Dc=1.78g/cm^3.Final R factor is 0.066.The result reveals that the[Mo_4S_4]cluster core and t-(dtp)^(-1)ligands are retained and only μ-bridged(dtp)^(-1)ligands are substituted by(C_6H_5CO_2)^(-1)in the substitution reaction,thus producing the new title cluster compound,the structure of which contains two species of bidentate ligand.
文摘Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds. The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identified as the benezenediazonium ion, the ultimate carcinogens, which could bind to DNA. The reaction conditions were investigated preliminarily. Some inhibitors and inducers of the reaction were discovered.
文摘Mesoporous TiO2 ceramic films have been prepared upon the Ti alloy substrate by the micro-arc oxidation (MAO) technology. To enhance the photo-catalytic property of the films, Eu2O3 particles were added into the electrolyte solution of Na2CO3/Na2SiO3. Scanning electron microscope (SEM), energy dispersive (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) are employed to characterize the modified films. Diffuse reflectance spectra (DRS) test, photo-generated current test and photo decomposition test are applied to evaluate the photo-catalytic property of the modified films. The results show that Eu2O3 transformed into one-dimensional (1-D) nano-wires embedded within the composite film, and the film has high photo-catalytic property.
文摘n.m, n.Om, nO.m and nO.Om compounds play an important role in the fundamental and applied aspects. As a part of our systematic studies of the above homologous series regarding the synthesis, characterization and phase transition studies, here the authors report the polarizabilities and orientational order parameter, S in N-(p-n-ethoxybenzylidene)-p-n-alkoxy anilines, 2O.Om with m = 3 to 10 liquid crystalline compounds except with m = 5 which has been already published. The rest of the compounds exhibit the nematic LC phase except with m = 10 which shows the smectic-C phase along the nematic phase which is originally not detected by Godzwon et al. But the author’s observations with TM and differential scanning calorimeter have shown the existence on SmC phase in addition to nematic phase. Further, SmC is clarified using the histogram technique whose details are given below and are published elsewhere. The orientstonal order parameter, S is estimated using different methods and compared with the value obtained from birefringence, δn = (n<sub>e</sub> – n<sub>o</sub>) where no field model is used. It is observed in these compounds case as in other LC compounds Vuks isotropic model is favored compared to that of anisotropic model proposed by Neugebauer.
文摘在 NCU PP技术沉积的 Ti N- Mo S2 / Ti N复合膜中添加 A1元素并改变部分沉积工艺 ,可以在 1Cr18Ni9Ti基体上沉积出 Ti Al N - Mo S2 / Ti Al N硬质润滑膜 .利用 SEM,XPS等手段研究涂层的成分、微观结构等 .通过摩擦学试验测定其结合强度等性能 .结果表明 ,在钻头上沉积 Ti Al N- Mo S2 / Ti Al N硬质膜 ,可使其在钻削过程中具有优异的耐磨、减摩和耐高温等性能 。
文摘A series of mixed oxide catalysts with different composition of Co-M-Al and Co-M-Ce- Al （M=Zn, Ni, Cu） were prepared by co-precipitation method from hydrotalcite-like compounds. The experimental results revealed the catalytic activity of Co-Ni-Al is slightly higher than that of Co-Zn-Al and much higher than that of Co-Cu-Al for direct decomposition of N2O. Moreover, addition of small amounts of Ce02 improved the catalytic activity signif- icantly and made the decomposition temperatures at which the N2O conversion was 50% and 90% （T50 and Tgo） both decreased 80 ℃ than those of Co-M-Al catalysts without CeO2 added. Further, potassium-load also promoted the catalytic activity, and the decomposi- tion temperatures of T50 and T90 both decreased approximately 50 ℃. It is significant for decomposing N2O from industries and reducing carbon emission from atmosphere.
