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Sensitivity to Combustible Gas for ZnO Thin Films

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Journal of Materials Science & Technology 1997年第4期13卷 302-305页

作者： Tan, gl Wu, JA Wu, XJ Dept. of Materials Science and Engineering Zhejiang University Hangzhou 310027 China

A fine polycrystalline ZnO thin film with 0.3 similar to 0.6 mu m grain size was obtained by sol-gel process and a consequential heat treatment at 500 degrees C. The process of preparing ZnO thin film was analysed. The sensitivity and conductivity of ZnO thin films as combustible gas (CO, CH4, H-2) sensor as well as the influence of catalyst and pH value of the precursor on its sensitivity were studied in detail. The structure characteristics of ZnO thin film by different process were investigated by X-ray diffraction, thermal analysis and photoelectron spectrometer. The atomic ratio of Zn to O on the surface of ZnO thin film was found to be 1.14:1 measured from XPS result. The conductivity of the thin film increases greatly when doped with Al3+ ion but decreases while doped with Na+ ion.

关键词： Zinc oxide

Ferromagnetism and ferroelectricity in a superlattice of antiferromagnetic perovskite oxides without ferroelectric polarization

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npj Computational Materials 2023年第1期9卷 632-637页

作者： Paresh C.Rout Avijeet Ray Udo Schwingenschlögl Physical Sciences and Engineering Division(PSE) King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia

We study the structural,electronic,and magnetic properties of the SrCrO_(3)/YCrO_(3) superlattice and their dependence on epitaxial *** discover that the superlattice adopts A-type antiferromagnetic(A-AFM)ordering in contrast to its constituents(SrCrO_(3):C-AFM;YCrO_(3):G-AFM)and retains it under compressive strain while becoming ferromagnetic(5μB per formula unit)at+1%*** obtained ferroelectric polarization is significantly higher than that of the R2NiMnO6/La2NiMnO6(R=Ce to Er)series of superlattices[***.5,4021(2014)]due to a large difference between the antipolar displacements of the Sr and Y *** superlattice is a hybrid-improper multiferroic material with a spontaneous ferroelectric polarization(13.5μC/cm^(2))approaching that of bulk BaTiO_(3)(19μC/cm^(2)).The combination of ferromagnetism with ferroelectricity enables multistate memory *** addition,the charge-order-driven p-type semiconducting state of the ferromagnetic phase(despite the metallic nature of SrCrO_(3))is a rare property and interesting for *** Carlo simulations demonstrate a magnetic critical temperature of 90 K for the A-AFM phase without strain and of 115 K for the ferromagnetic phase at+5%strain,for example.

关键词： ferroelectric superlattice ferromagnetic

Eremophilenolides from Cacalia Roborowskii

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维普期刊数据库

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Chinese Chemical Letters 1998年第1期9卷 65-68页

作者： Zhang, SM Zhao, gl Lin, GQ Chinese Acad Sci Shanghai Inst Organ Chem Shanghai 200032 Peoples R China

From the extracts of the roots of Cacalia roborowskii (Maxim) Ling, five new eremophilenolides were isolated and their structures identified as 8 beta, 10 beta-dihydroxy-6 beta-methoxyleremophilenolide (1), 3 beta-acetoxyl-8 beta, 10 beta -dihydroxy-6 beta-methaxyeremophilenolide (2), 3 beta-angeloyloxy-8 beta-, 10 beta-dihydroxy-6 beta-methoxyeremophilenolide (3), 3 beta-(2-methylbutyryloxy)-8 beta, 10 beta-dihydroxy-6 beta-methoxyeremophilenolide (4), and 8 beta-hydroxy-6 beta-methoxyeremophil-7(11), 9-dien-8, 12-olide(5), based on 1D and 2D NMR experiments.

关键词： eremophilenolide root herb Cacalia roborowskii (maxim) Ling

Microcracking Behaviour of a TiAl-base Alloy with Different Microstructures during Compression

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Journal of Materials Science & Technology 1998年第5期14卷 415-418页

作者： Zhang, WJ Chen, gl Evangelista, E Francesconi, L Univ Sci & Technol Beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China Univ Ancona Dept Mech I-60131 Ancona Italy

The microcracking behaviour of TiAl-based alloys with the duplex and fully-lamellar microstructures was studied during compression. It was found that the fracture involves propagation of the existing microcracks and development of more new nuclei, instead of being a nucleation-controlled event. The lamellar interfaces, especially those having an angle of about 0 similar to 30 degrees C to the loading axis, were found to be the favourable nucleation sites. Microcrack nucleation is likely to be initiated by tensile normal stress concentrated on the lamellar interfaces.

关键词： Titanium alloys

A Study on the Maneuvering Motion of a Low Speed Submersible

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China Ocean Engineering 1997年第4期12卷 457-466页

作者： Huang, gl Lin, TW Yan, NC Shanghai Jiao Tong Univ Shanghai 200030 Peoples R China

In this paper, the maneuvering characteristics of a low speed submersible are investigated. First, the captive model tests are carried out to obtain the hydrodynamic forces acting on the submersible using a Planar Motion Mechanism (PMM). For the hydrodynamic forces within a wide range of attack angles, the hydrodynamic coefficients which are usually used in the conventional maneuvering motion are quite difficult to be applied. In this case, a Fourier series is adopted to represent the hydrodynamic forces and it fits the experimental data well. Then, based on the experimental results the simulation calculations are made to predict some of the maneuvering performance of the low speed submersible.

关键词： low speed submersible maneuverability model test hydrodynamic free

Effect of diluent and reaction parameter on selective oxidation of propane over MoVTeNb catalyst using nanoflow catalytic reactor

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Journal of Natural Gas Chemistry 2008年第2期17卷 130-134页

作者： Restu Kartiko Widi Sharifah Bee Abdul Hamid Robert Schlgl Department of Mathematic and Natural Science University of SurabayaTG 6th floor Raya Kalirungkut 60293SurabayaIndonesia Combinatorial Technology and Catalysis Research Centre University of Malaya50603Kuala LumpurMalaysia combinatorial Technology and Catalysis Research Centre University of Malaya50603Kuala LumpurMalaysia: Fritz-Haber-Institute der Max-Planck-Gesellschaft Faradayweg 4-614195 BerlinGermany

The selective oxidation of propane to acrylic acid over an MoVTeNb mixed oxide catalyst, dried and calcined before reaction has been studied using high-throughput instrumentation, which is called nanoflow catalytic reactor. The effects of catalyst dilution on the catalytic performance of the MoVTeNb mixed oxide catalyst in selective oxidation of propane to acrylic acid were also investigated. The effects of some reaction parameters, such as gas hourly space velocity （GHSV） and reaction temperature, for selective oxidation of propane to acrylic acid over diluted MoVTeNb catalyst have also been studied. The configuration of the nanoflow is shown to be suitable for screen catalytic performance, and its operating conditions were mimicked closely to conventional laboratory as well as to industrial conditions. The results obtained provided very good reproducibility and it showed that preparation methods as well as reaction parameters can play significant roles in catalytic performance of these catalysts.

关键词： selective oxidation propane acrylic acid MoVTeNb mixed oxide catalyst

Eremophilane Sesquiterpenes from Cacalia Roborowskii

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Chinese Chemical Letters 1998年第1期9卷 61-64页

作者： Zhang, SM Zhao, gl Li, R Lin, GQ Chinese Acad Sci Shanghai Inst Organ Chem Shanghai 200032 Peoples R China

Four new eremophilane type sesquiterpenes were isolated from the roots of Cacalia roborowskii (Maxim) Ling. Their structures were established as 8-oxo-eremophila-6, 9-dien-12-oic acid (1), 3 beta-acetoxyl-8-oxo-eremophila-6, 9-dien-12-oic acid (2), 3 beta-angeloyoxyl-8-oxo-eremophilad, 9-dien-12-oic acid (3) and 3 beta-(2-methylbutyryloxyl)-8-oxo-eremophilia-6,9-dien-12-oic acid (4) by means of 1D and 2D NMR spectroscopy.

关键词： eremophilane sesquiterpene Cacalia roborowskii

A Preliminary Raman Investigation of the Lead Titanate Thin Films via Sol-Gel Process

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Journal of Materials Science & Technology 1997年第4期13卷 306-308页

作者： Zhu, T Han, GR Zhao, gl Ding, ZS Han, ZF UNIV SCI & TECHNOL CHINA NATL SYNCHROTRON RADIAT LABHEFEI 230026PEOPLES R CHINA ZHEJIANG UNIV DEPT MAT SCI & ENGNHANGZHOU 310027PEOPLES R CHINA

Raman spectra of the PbTiO3 films via sol-gel process were investigated by using a Jobin Yvon U1000 system. Compared with the Raman spectra of the PbTiO3 single crystals, Raman peaks of PbTiO3 films shift downward, which is attributed to the stress effect in the PbTiO3 films exerted by the substrate and the size effect on the Raman frequencies.

关键词： Lead compounds

A Fractal Study on Brittle-Ductile Transition forTi-24Al-11Nb Alloy

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Journal of Materials Science & Technology 1995年第5期11卷 340-344页

作者： CHEN, gl WANG, YD HUANG, YD SUN, ZQ YANG, WY Beijing Univ of Science and Technology Beijing China

The mechanical behaviours of Ti-24Al-11Nb alloy in the brittle-ductile transition (BOT) have been investigated by using three-point bending tests. The temperature dependence of the fractal dimensions and fractal characterization of fracture surfaces are presented. The probable mechanism controlling BDT of intermetallic alloys are proposed according to fractal ***. it is found that there is a positive relationship between the fractal dimension and fracture toughness in BDT for Ti-24Al-11Nb

关键词： Al Ti A Fractal Study on Brittle-Ductile Transition forTi-24Al-11Nb Alloy OO