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Journal of Materials Science & Technology 2011年第7期27卷 585-593页

作者： l.Benhaddad l.Makhloufi B.Messaoudi1 k.Rahmouni h.Takenouti laboratoire de Technologie des Matériaux et Génie des Procédés (lTMGP) Département de Génie des Procédés. Université A. MiraRoute de Targa Ouzemmour06000 BéjaiaAlgeria UPR 15 du CNRS lISE-laboratoire Interfaces et Systèmes Electrochimiques UPMC University Paris 06Case 133 4 place Jussieu 75252 Paris Cedex 05 France UPR 15 du CNRS lISE-laboratoire Interfaces et Systèmes Electrochimiques UPMC University Paris 06Case 1334 place Jussieu 75252 Paris Cedex 05France

The synthesis of MnO2 powders by hydrothermal method with different oxidizing agents has been successfully achieved. The characterizations by scanning electron microscopy, energy-dispersive X-ray analyses, transmission electron microscopy, and X-ray diffraction techniques confirm the synthesis of nanostructured γ-MnO2 powders. The electrochemical reactivity of these powders in 1 mol/l kOh is investigated by cyclic voltammetry and electrochemical impedance spectroscopy （EIS） by using microcavity electrode. The results reveal that the MnO2 synthesized with Na2S2O8 shows the highest electrochemical reactivity in the test medium. This is due both to its large expanded surface area and its crystallographic variety γ-MnO2 formed in the matrix of ramsdellite, which is largely used as cathodic material for primary batteries. however, the presence of pyrolusite in the structure of γ-MnO2 synthesized with （Nh4）2S2O8 decreases its electrochemical reactivity due to its narrow 1×1 size tunnel, which hinders the protons insertion.

关键词： hydrothermal processing Electrochemical impedance spectroscopy (EIS) Cyclic voltammetry X-ray diffraction γ-MnO2

Electronic structure of correlated topological insulator candidate YbB6 studied by photoemission and quantum oscillation

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Chinese Physics B 2020年第1期29卷 70-75页

作者： T Zhang G li S C Sun N Qin l kang S h Yao h M Weng S k Mo l li Z k liu l X Yang Y l Chen State key laboratory of low Dimensional Quantum Physics Department of PhysicsTsinghua UniversityBeijing 100084China Department of Physics University of MichiganAnn ArborMI 48109USA Beijing National laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China National laboratory of Solid State Microstructures&Department of Materials Science and Engineering Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Quantum Matter BeijingChina Songshan lake Materials laboratory Dongguan 523808China CAS Center for Excellence in Topological Quantum Computation Beijing 100190China Physical Science laboratory Huairou National Comprehensive Science CenterBeijing 101400China Advanced light Source Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA School of Physical Science and Technology ShanghaiTech University and CAS-Shanghai Science Research CenterShanghai 201210China ShanghaiTech laboratory for Topological Physics Shanghai 200031China Frontier Science Center for Quantum Information Beijing 100084China Department of Physics Clarendon LaboratoryUniversity of Oxford Parks RoadOxford OX13PUUK

Angle-resolved photoemission spectroscopy(ARPES)and torque magnetometry(TM)measurements have been carried out to study the electronic structures of a correlated topological insulator(TI)candidate Yb *** observed clear surface states on the[001]surface centered at theГ^- and М^- points of the surface Brillouin ***,the fermiology revealed by the quantum oscillation of TM measurements agrees excellently with ARPES ***,the band structures we observed suggest that the band inversion in Yb B6 happens between the Yb5 dand B2bands,instead of the Yb5dand Yb4fbands as suggested by previous theoretical investigation,which will help settle the heavy debate regarding the topological nature of samarium/ytterbium hexaborides.

关键词： topological insulator electronic structure surface states

The Formation of Nano-Size SiO_2 Thin Film on an Aluminum Plate with hexamethyldisilazane (hMDSA) and hexamethyldisiloxane (hMDSO)

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Journal of Thermal Science 2003年第1期12卷 89-96页

作者： h.k.Ma E.Zhao k.M.Chung C.l.Yeh Dept of Mechanical Engineering National Taiwan UniversityDept of Mechanical Engineering National Taiwan UniversityDept of Mechanical Engineering National Taiwan UniversityDept of Mechanical Engineering Da-Yeh University 112 Taipei Taiwan 10764 China Taipei Taiwan 10764 ChinaTaipei Taiwan 10764 ChinaShan-Jeau Rd Dah-Tsuen Chang-Hwa Taiwan 51505 China

This study is using hMDSA (C6h19NSi2) or hMDSO (C6h18OSi2) vapor into C3h8/air premixed flames to form SiO2 thin film on the surface of an aluminum plate. With the addition of hMDSO or hMDSA to premixed flames, an orange secondary flame or a flame brush appeared and was contributed to the formation of Sio2 particles. Based upon the EDS, XPS and FTIR analysis, it is believed that the synthesized products consist of mainly SiO2 and a small amount of SiO. The pure SiO2 crystal structure, was proved by XRD analysis, which may form from the SiO2 amorphous structure after high temperature (1300C) thermal treatment. The nano-size SiO2 particles, which ranged from 2.5-25 nm, are proved by analysis of the BET and TEM. A 2-D CFD-RC code with 12 reduced chemical reaction mechanism, based upon the SIMPlER procedure, was successfully employed to predict the flame temperature and both of the SiO2 and SiO concentration profiles. Compared with the experimental results, the calculated temperature profiles in the post-flame region are in good agreement with the measured data and observation phenomena.

关键词： nano size thin film SiO2.

Contamination by Organochlorine Pesticides in the Estuaries of Southeast China

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Chemical Research in Chinese Universities 2002年第2期18卷 153-160页

作者： Z.l.Zhang h.S.hong J.l.Zhou M.h.Dai k.Maskaouib W.Q.Chen Department of Environmental Science and Engineering Tsinghua POPs Research CentreTsinghua UniversityBeijing 100084China key laboratory of Marine Environmental Science of Ministry of Education Environmental Science Research CentreXiamen Universi-tyXiamen 361005China School of Chemistry Physics and Environmental ScienceUniversity of SussexFalmerBrighton BN19QJUK

Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiulong River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC ECD. The results showed that the contamination levels were similar in these three estuaries. The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocyclohexane(hCh) compounds, β hCh was found to be the most important isomer. The analysis of 1,1,1 trichloro 2,2 bis chlorophenyl ethane(DDT) and its metabolites showed that 1,1 dichloro 2[ o chlorophenyl] 2[ p chlorophenyl] ethylene(DDE) was dominant in the group.

关键词： Organochlorine insecticides DDT lindane Jiulong River Estuary Minjiang River Estuary Pearl River Estuary Water Sediment

Transport of Nitrogen Assimilation in Xylem Vessels of Green Tea Plants Fed with Nh_4-N and NO_3-N

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Pedosphere 2008年第2期18卷 222-226页

作者： k. Oh T. kATO h. l. XU Center for Environmental Science in Saitama Saitama 347-0115 （Japan） Jinenjou-no-kai NPO Shizuoka 421-0302 （Japan） International Nature Farming Research Center 5632 Hata Nagano 390-1401 （Japan）

An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-Nh4 were fed to the root of tea plants （Camellia sinensis l.）. Results showed that the main amino acids were glutamine, theanine, axginine, asparic acid and glutamic acid, which accounted for 49%, 17%, 8%, 7%, and 4%, respectively, of the total amino acids in the xylem sap. After the tea plants were fed with 15^N-NO3 and 15^N-Nh4 for 48 h, the amount of total amino acids in xylem sap significantly increased and those fed with 15^N-Nh4 had higher increment than those with 15^N-NOa. Two hours after 15^N- NO3 and 15^N-Nh4 were fed, 15N abundance in glutamine, asparagine, glutamic acid, alanine, and arginine were detected and increased quickly over time. This indicated that it took less than 2 h for NO3-N and Nh4-N to be absorbed by tea roots, incorporated into the above amino acids and transported to the xylem sap. Rapid increase in 15^N-NO3 in the xylem sap of tea plants fed with 15^N-NO3 indicated that nitrate could be directly transported to the xylem sap. Glutamine, theanine, and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15^N-NO3 and 15^N-Nh4.

关键词： amino acid 15^N nitrogen assimilation tea plant xylem sap

A new semi-quantitative Surface-Enhanced Raman Spectroscopy (SERS) method for detection of maleimide (2,5-pyrroledione) with potential application to astrobiology

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Geoscience Frontiers 2021年第5期12卷 421-426页

作者： J.Aramendia l.Gomez-Nubla M.l.Tuite k.h.Williford k.Castro J.M.Madariaga Jet Propulsion laboratory California Institute of Technology4800 Oak Grove DrPasadenaCA 91109United States Department of Analytical Chemistry University of the Basque Country UPV/EHUP.O.Box 64448080 BilbaoSpain

Nitrogen-containing heterocyclic compounds are fundamental biochemical components of all life on Earth and,presumably,life elsewhere in our solar *** and characterization of these compounds by traditional solvent extraction,chromatographic separation,and GC-MS analysis require more sample mass than will be available from samples returned to Earth from *** its small sample mass requirement,Surface Enhanced Raman Spectroscopy could be an appropriate technique for analysis of returned *** have developed a SERS method for the detection of maleimide(2,5-pyrroledione),an N-containing heterocycle with a structure that is widespread in *** semi-quantitative methodology accurately determines maleimide concentration in the range from 60 mg/ml to 120 mg/*** present a maleimide SERS standard spectrum which will be useful as a reference for future *** present work demonstrates an easy,accurate,and effective method for the non-destructive qualitative and semi-quantitative study of maleimide as a first step toward developing a method for analysis of related compounds.

关键词： Maleimide Surface-Enhanced Raman Spectroscopy Astrobiology Biosignature Extraterrestrial life

INFlUENCE OF FIBER COATING ON TENSIlE BEhAVIOR OF UNIDIRECTIONAl C/Mg COMPOSITES

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Acta Metallurgica Sinica(English letters) 1997年第5期10卷 398-402页

作者： Zhang, k. Wang, Y.Q. Zhou, B.l. Zhou, Y.h. li, h.l. Inst of Metal Research Chinese Acad of Sciences Shenyang China

The mechanical properties and deformation mechanisms of unidirectional carbon fiber reinforced magnesium composites under tensile loading are studied. Two different materials are used as fiber coatings: a single silica and a gradient C/SiC/SiO[sb 2]. The results show that, under the same preparation conditions, composite with the former coating is broken in a non-cumulative mode and its failure stress is rather low. Conversely, the latter coating demonstrates much better efficiency and the corresponding composite is broken in a cumulative mode.

关键词： Metallic matrix composites Carbon fibers Tensile strength Elastic moduli Coatings Silica Deformation Crack propagation Crack initiation Fracture Stresses Strain

Relationship between the fatigue behavior and grain structures of an as-extruded Mg-6.2%Zn-0.6%Zr(in wt.%)alloy

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Journal of Materials Science & Technology 2023年第18期149卷 119-126页

作者： B.J.Wang D.k.Xu C.l.Jiang l.Y.Sheng E.h.han School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang 110159China key laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Binzhou Institute of Technology Binzhou 256606China Shandong key laboratory of Advanced Aluminium Materials and Technology Binzhou 256606China Shenzhen Institute Shenzhen Key Lab Human Tissue Regenerate&RepairPeking UniversityShenzhen 518057China

Through investigating the tension-tension fatigue behavior of an as-extruded Mg-6.2 wt.%Zn-0.6 wt.%Zr(Zk60)alloy,it revealed that the determined fatigue strength at 107 cycles was quite sensitive to the grain *** them,the fine grain structure had the highest fatigue strength of 130 MPa,whereas the typical“bi-modal”grain structure had the lowest fatigue strength of 110 *** analysis demon-strated that for the fine grain structure,fatigue cracks preferentially nucleated at grain *** the“bi-modal”and coarse grain structures,the fatigue crack initiation was dominated by the cracking along slip bands.

关键词： Mg alloys Grain structure Cyclic slips Fatigue behavior Crack initiation

Some stromatic pyrenomycetous fungi from northern ***,Camillea and hypoxylon(Xylariaceae)

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Fungal Diversity 2012年第4期55卷 65-76页

作者： l.N.Vasilyeva S.l.Stephenson k.D.hyde A.h.Bahkali Institute of Biology and Soil Science Far East Branch of the Russian Academy of SciencesVladivostok 690022Russia University of Arkansas FayettevilleAR 72701USA Institute of Excellence in Fungal Research Mae Fah Lung UniversityChiang Rai 57100Thailand School of Science Mae Fah Lung UniversityChiang Rai 57100Thailand Botany and Microbiology Department College of ScienceKing Saud UniversityRiyadh 11442Saudi Arabia

Fourteen species of stromatic pyrenomycetous fungi(family Xylariaceae)collected in northern Thailand are *** of these(Biscogniauxia lithocarpi,Camillea malaysiensis ***,hypoxylon juventuterubrum,***,***,and ***)are described as taxa new to *** of these taxa are provided,and they are compared with similar taxa known from the Western hemisphere.

关键词： Ascomycota SE Asia Taxonomy Xylariales

Biogenic amino acid methionine-based corrosion inhibitors of mild steel in acidic media

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International Journal of Minerals,Metallurgy and Materials 2019年第4期26卷 467-482页

作者： l.k.M.O.Goni M.A.Jafar Mazumder S.A.Ali M.k.Nazal h.A.Al-Muallem Chemistry Department King Fahd University of Petroleum and Minerals

N,N-Diallyl methionine ethyl ester hydrochloride 5 underwent alternating copolymerization with SO_2 via the Butler cyclopolymerization protocol in dimethyl sulfoxide(DMSO) to give water-soluble cycloterpolymer 6 with a ～1:1 molar ratio of sulfide and sulfoxide groups as a result of oxygen transfer from DMSO. half of the sulfide groups in 6, upon oxidation with h_2O_2, afforded polymer sulfoxide 7 and polymer sulfone 8. The solution properties of these polymers were determined via a viscometric technique. The thermal stability of these polymers was determined by thermogravimetric analysis. The inhibition efficiency obtained from gravimetric mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques agreed well with each other. The corrosion efficiencies increase with increasing concentration of the polymers. At a polymer concentration of 175 mM, the maximum inhibition efficiency of copolymer compounds 6–8 was determined to be 92%, 97%, and 95%, respectively. The synthesized polymer compounds acted as mixed-type inhibitors. Polymer compound 7 adsorbed onto the metal surface via chemisorption and physisorption and obeyed langmuir, Temkin, and Freundlich adsorption isotherms. Analyses by X-ray photoelectron spectroscopy and scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated that the adsorbed polymers formed a thin film on the metal surface and prevented further corrosive attack.

关键词： cyclopolymerization methionine methionine sulfoxide methionine sulfone diallylamine salt corrosion inhibition