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Methanol oxidation in acidic and alkaline electrolytes using PtruIn/C electrocatalysts prepared by borohydride reduction process

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燃料化学学报 2018年第12期46卷 1462-1471页

作者： Santos M.C.L. Nandenha j. Ayoub j.M.S. Assumpao M.H.M.T. Neto A.O. Instituto de Pesquisas Energéticas e Nucleares IPEN/CNEN-SPAv.Prof.Lineu Prestes2242 Cidade UniversitáriaCEP 05508-000Sao PauloSPBrazil Universidade Federal de Sao carlos UFSCar Campus Lagoa do Sino Rodovia Lauri Simoes de Barros Km 12 CEP 18290-000-Buri-Sao Paulo SP Brazil

PtruIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,ruCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and carbon Vulcan XC72 as support. The synthetized PtruIn/C electrocatalysts were characterized by X-ray diffraction( XrD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( ca) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XrD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and ca. Ptru/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtruIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and Ptru/C for both electrolytes. The best performance obtained by PtruIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.

关键词： borohydride reduction process PtruIn/C electrocatalysts methanol oxidation acidic and alkaline electrolytes polarization curves

Decoding earth’s plate tectonic history using sparse geochemical data

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Geoscience Frontiers 2020年第1期11卷 265-276页

作者： Michael G.Tetley Zheng-Xiang Li Kara j.Matthews Simon E.Williams r.Dietmar Müller EarthByte Group School of GeosciencesUniversity of SydneyNSWAustralia Seismological Laboratory California Institute of TechnologyPasadenaCAUSA Data61 CSIROAustralian Technology ParkNSWAustralia Earth Dynamics research Group The Institute for Geoscience Research(TIGeR)School of Earth and Planetary SciencesCurtin University of TechnologyGPO Box U1987PerthWA 6845Australia

Accurately mapping plate boundary types and locations through time is essential for understanding the evolution of the plate-mantle system and the exchange of material between the solid Earth and surface ***,the complexity of the Earth system and the cryptic nature of the geological record make it difficult to discriminate tectonic environments through deep *** we present a new method for identifying tectonic paleo-environments on Earth through a data mining approach using global geochemical *** first fingerprint a variety of present-day tectonic environments utilising up to 136 geochemical data attributes in any available combination.A total of 38301 geochemical analyses from basalts aged from 5-0 Ma together with a well-established plate reconstruction model are used to construct a suite of discriminatory models for the first order tectonic environments of subduction and mid-ocean ridge as distinct from intraplate hotspot oceanic environments,identifying 41,35,and 39 key discriminatory geochemical attributes,*** training and validation,our model is applied to a global geochemical database of 1547 basalt samples of unknown tectonic origin aged between 1000-410 Ma,a relatively ill-constrained period of Earth’s evolution following the breakup of the rodinia supercontinent,producing 56 unique global tectonic environment predictions throughout the Neoproterozoic and Early *** are used to discriminate between three alternative published rodinia configuration models,identifying the model demonstrating the closest spatio-temporal consistency with the basalt record,and emphasizing the importance of integrating geochemical data into plate *** approach offers an extensible framework for constructing full-plate,deeptime reconstructions capable of assimilating a broad range of geochemical and geological observations,enabling next generation Earth system models.

关键词： Plate tectonics Geochemistry Geodynamics Supercontinents rodinia Big data

Engineering Economy Analysis on the Production of Iron Ore in Nigeria

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Geomaterials 2011年第1期1卷 14-20页

作者： r. A. Adebimpe j. M. Akande 不详

In line with the Federal government decision to attract direct foreign investment to the solid mineral sector and to further diversify the Nigerian economy;this study used the discounted cash flow micro-economic as-sessment to evaluate large-scale iron ore production in Nigeria. The iron ore proj.ct has an initial investment cost of US$ 73.934 m, annual expenditure and benefit of US$ 48.128 m and US$ 270 m respectively .The net present value (NPV), internal rate of return (Irr) and payback period of financial analysis at 100% ca-pacity utilizations are US$ 833.10 m, 444.36% and 6 years respectively. The economic assessment also shows a positive NPV at both 75% and 60% capacity utilizations. The study further show that the iron ore proj.ct has good economic potential and will also guide potential investor(s) in making decision on whether or not to commit resources to the proj.ct.

关键词： Iron Ore Micro-Economic Assessment Solid Mineral Sector Nigeria

Celebrating Plant Cells:A Special Issue on Plant Cell Biology

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j.urnal of Integrative Plant Biology 2007年第8期49卷 1089-1090页

作者： Zhenbiao Yang Center for Plant Cell Biology,Department of Botany and Plant Sciences,University of california,riverside,ca 92521,USABe Liu Section of Plant Biology,University of california,Davis,ca 95616,USA Center for Plant Cell Biology Department of Botany and Plant Sciences University of California Riverside CA 92521 USA Section of Plant Biology University of California Davis CA 95616 USA

A special issue on plant cell biology is long overdue for j.PB! In the last two decades or so, the plant biology community has been thrilled by explosive discoveries regarding the molecular and genetic basis of plant growth, development, and responses to the environment, largely owing to recent maturation of model systems like Arabidopsis thaliana and the rice Oryza sativa, as well as the rapid development of high throughput technologies associated with qenomics and proteomics.

关键词： Celebrating Plant Cells

Plant carbonic Anhydrases： Structures, Locations, Evolution, and Physiological roles

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Molecular Plant 2017年第1期10卷 30-46页

作者： robert j. DiMario Harmony Clayton Ananya Mukhedee Martha Ludwig j.mes V. Moroney Department of Biological Sciences Louisiana State University Baton Rouge LA 70803 USA School of Chemistry and Biochemistry University of Western Australia Perth WA 6009 Australia

carbonic anhydrases （cas） are zinc metalloenzymes that catalyze the interconversion of CO2 and HCO3- and are ubiquitous in nature. Higher plants contain three evolutionarily distinct ca families, αcas, 13cas, and γcas, where each family is represented by multiple isoforms in all species. Alternative splicing of ca transcripts appears common; consequently, the number of functional ca isoforms in a species may exceed the number of genes. cas are expressed in numerous plant tissues and in different cellular locations. The most prevalent cas are those in the chloroplast, cytosol, and mitochondria. This diversity in location is paralleled in the many physiological and biochemical roles that cas play in plants. In this review, the number and types of cas in C3, C4, and crassulacean acid metabolism （caM） plants are considered, and the roles of the α and ycas are briefly discussed. The remainder of the review focuses on plant βcas and includes the identification of homologs between species using phylogenetic approaches, a consideration of the inter- and intracellular localization of the proteins, along with the evidence for alternative splice forms. Current understanding of βca tissue-specific expression patterns and what controls them are reviewed, and the physiological roles for which βcas have been implicated are presented.

关键词： carbonic anhydrase regulation alternative splicing physiological role

FrACTUrE TOUGHNESS OF OrDErED INTErMETALLIC COMPOUNDS FrOM SMALL DISKSHAPED SPECIMENS

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中国有色金属学会会刊：英文版 1999年第S1期9卷 106-116页

作者： Alan j.Ardell Department of Materials Science and Engineering, University of california, Los Angeles, ca 90095 1595, U.S.A.

The miniaturized disk bend test(MDBT) can be used to measure the fracture toughness at “infinite" crack length, K ∞, of ordered intermetallic compounds. The specimens tested are disks 3 mm in diameter and typically range in thickness from 250 to 400 μm. A Vickers indentation is impressed within ±10 μm of the center of a metallographically polished disk under a known load, F . The specimen is then subj.cted to biaxial loading, with the indented side in tension, and tested to failure. In completely brittle intermetallics the fracture stress, σ f, is calculated using a standard formula and measured experimentally as a function of F . When plasticity intervenes prior to fracture it is necessary to calculate the stress using finite element modeling (FEM), the FEM program NIKE2D has been used. Whether or not the specimens deform plastically, the resulting data on σ f vs F are analyzed using established equations of fracture mechanics in conj.nction with an empirical rising r curve equation that characterizes the increase in fracture resistance, K r( c ), with crack length, c . results are presented on several ordered intermetallic compounds. These include Ni 3Ge and Ti 5Si 3, which exhibit no ductility prior to fracture, and NiAl and a complex TiAl alloy, which both exhibit limited ductility before fracturing. The values of K ∞ determined with the MDBT are in very good agreement with values of K IC measured using conventional methods.

关键词： ordered intermetallics Ni 3Ge Ti 5Si 3 TiAl fracture toughness miniature disk bend test

Flow of Steel in Mold region During Continuous casting

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j.urnal of Iron and Steel research International 2007年第2期14卷 30-35,41页

作者： ZHANG Xing-guo ZHANG Wen-xiao j.N j.n-ze j. W. Evans research Center of Foundry Engineering Dalian University of Technology Dalian 116023 Liaoning China Department of Material Science and Engineering University of California at Berkeley Berkeley CA94720 USA

The particle image velocimetry （PIV） technique was used to study the fluid flow phenomena that occurred during continuous casting, using a water model with dimensions of 1 840mm× 280 mm. Two types of solidified shells, i. e. , the smooth type and the coarse type, were used to characterize the dendrite in order to simulate different liquid-solid interfacial conditions. The influence of the nozzle angle and the immersion depth of nozzle, as well as the casting speed on the flow behavior was investigated quantitatively. The results were as follows：（1） There are two large recirculations above and below the fluid j.t in the mold, respectively, under the smooth interface condition. However, in the case of the dendrite solidified shell, it was found that the flow velocity of the fluid decreased and more smaller vortices appeared in the upper region of the mold. （2） The angle and the immersion depth of nozzle are two important factors affecting the flow pattern, and they are also capable of bringing about the change in the flow direction. （3） The higher the casting speed, the higher are the j.t stream and the impacting point on the narrow face. However, the high casting speed causes serious fluctuation of the meniscus, and correspondingly leads to various defects.

关键词： particle image velocimetry continuous casting steel fluid flow

Preprotein Import into Chloroplasts via the Toc and Tic Complexes Is regulated by redox Signals in Pisum sativum

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Molecular Plant 2009年第6期2卷 1181-1197页

作者： Anna Stengel j. Philipp Benz Bob B. Buchanan j.rgen Soil Bettina Bolter Munich Center for Integrated Protein Science CiPS^M Ludwig-Maximilians-Universitat Munchen Feodor-Lynen-Strasse 25 D-81377 Munich Germany Department of Biology I Botany Ludwig-Maximilians-Universitat Munchen Groβhaderner Strasse 2-4 D-82152 Planegg-Martinsried Germany Department of Plant and Microbial Biology University of California 411 Koshland Hall Berkeley CA 94720 USA

The import of nuclear-encoded preproteins is necessary to maintain chloroplast function. The recognition and transfer of most precursor proteins across the chloroplast envelopes are facilitated by two membrane-inserted protein complexes, the translocons of the chloroplast outer and inner envelope （Toc and Tic complexes, respectively）. Several signals have been invoked to regulate the import of preproteins. In our study, we were interested in redox-based import regulation mediated by two signals： regulation based on thiols and on the metabolic NADP＋/NADPH ratio. We sought to identify the proteins participating in the regulation of these transport pathways and to characterize the preprotein subgroups whose import is redox-dependent. Our results provide evidence that the formation and reduction of disulfide bridges in the Toc receptors and Toc translocation channel have a strong influence on import yield of all tested preproteins that depend on the Toc complex for translocation. Furthermore, the metabolic NADP＋/NADPH ratio influences not only the composition of the Tic complex, but also the import efficiency of most, but not all, preproteins tested. Thus, several Tic subcomplexes appear to participate in the translocation of different preprotein subgroups, and the redox-active compo- nents of these complexes likely play a role in regulating transport.

关键词： Metabolic regulation molecular transport transport processes/kinetics chloroplast biology protein targeting.

raman and FTIr Spectroscopic Evaluation of Clay Minerals and Estimation of Metal Contaminations in Natural Deposition of Surface Sediments from Brahmaputra river

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International j.urnal of Geosciences 2016年第7期7卷 873-883页

作者： Bhaskar j. Saikia G. Parthasarathy r. r. Borah r. Borthakur Department of Physics Anandaram Dhekial Phookan College Nagaon India National Geophysical research Institute (CSIr-NGrI) Hyderabad India Department of Physics Nowgong College Nagaon India Department of Physics Assam Down Town University Guwahati India

This study demonstrates the compositional and structural analysis of surface sediments in natural depositional environment of the Brahmaputra river using X-ray fluorescence, raman spectroscopic and Fourier transform infrared spectroscopic techniques. The main peaks in the raman and infrared spectra reflected Al-OH, Al-O and Si-O functional groups in high frequency stretching and low frequency bending modes. The raman and infrared spectra reveals the nature of clay (kaolinite) associated with quartz. The infrared spectra are indicative to the weathered metamorphic origin of the silicate minerals. The relative distributions of the contaminations in the sediment are: Si > Al > Fe > Mg > ca > K > Ti > Mn > Cr >Ni > Zn > Cu > Co. The metal contaminations in the sediments are investigated by calculating the enrichment factor, contamination factor, geo-accumulation index and pollution load index. The relative distributions of the contamination among the samples are: Cu > Si > Mn > Mg > Ni > Cr > Ti > Al > Co > Pb > K > ca > Zn. The investigating factors suggest the significant contamination in the sediment is due to Cu. The strong positive correlation among Al, Fe, Mg and K suggests association of sediments with clay. The elemental correlation is indicative to the metamorphosed pyrophanite (MnTiO3) deposition.

关键词： raman Spectroscopy Sediment Clay Metals Pollution Brahmaputra river