检索结果-南通市图书馆

Efficient photocatalytic reduction of CO2 to form.te by a m.lecular noble m.tal-free system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chem.stry 2025年第1期68卷 152-156页

作者： Lihua Zhang Lingjing Chen Huatian Shi Yue Wei Gui Chen Tai-Chu lau School of Environm.nt and Civil Engineering Research Center for Eco-environmental Engineering Dongguan University of Technology Departm.nt of Chem.stry and Institute of m.lecular Functional m.terials City University of Hong Kong

Reducing CO2to carbon-neutral solar fuels can not only alleviate the energy dem.nd but also m.tigate the greenhouse *** present,developing an efficient non-noble m.tal photo/electrocatalytic system.for converting CO2to a specific product beyond CO is still a big ***,we report a new cobalt com.lex bearing 2,2′-bi-1,10-phenanthroline ligand that can photocatalytically reduce CO2to form.te （HCOO-）.Turnover num.er （TON） for HCOO-up to 677 with 99%selectivity can be achieved using organic dyes purpurin as photosensitizer and 1,3-dim.thyl-2-phenyl-2,3-dihydro-1H-benzo[d]im.dazole （BIH） as sacrificial reductant in a CO2-saturated Nm./TEA （v/v,3:1） solution under visible light *** potential electrolysis at-1.41 V （***/Ag Cl） in the presence of 12 m.m.Et3NHBF4also produced HCOO-with Faradaic efficiency of 39%.Spectroscopic and electrochem.cal studies suggest that a[CoI-H]species is the key interm.diate for CO2reduction.

关键词： photocatalysis noble m.tal-free CO2 reduction form.te cobalt hydride

Jet flows from.bubbles during subcooled pool boiling on m.cro wires

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2005年第4期48卷 385-402页

作者： D. m. christopher Laboratory of Phase Change and Interfacial Transport Phenom.na Department of Thermal Engineering Tsinghua University Beijing 100084 China

An experim.ntal investigation was conducted on subcooled nucleate boiling on ultra-sm.ll wires having diam.ters of 25―100 μm. High-speed photography and laser PIV (Particle Im.ge Velocim.try) technology were used to visually observe the bubble dynam.cs. For highly subcooled boiling at m.derate heat fluxes, the bubbles generally rem.ined attached to the m.cro heating wires and bubble-top jet flows were clearly observed. Sm.ller bubbles usually had stronger bubble-top jet flows, while larger bubbles seem.d to produce m.lti-jet flows. The structures of the bubble-top jet flows, as well as m.lti-jet flows, were proposed from.the experim.ntal observation. A m.del was developed to describe jet flow phenom.na from.bubbles on m.cro wires. Num.rical sim.lations for bubbles having diam.ter of 0.03 and 0.06 m. showed that both the bubble-top and m.lti-jet flows were induced by a strong m.rangoni effect due to high tem.erature gradients near the wire. The predicted velocity m.gnitudes and flow structures agreed very well with experim.ntal m.asurem.nts. The bubble size relative to the wire is an im.ortant factor affecting the jet flow structure. For a 0.03 m. bubble on a 0.1 m. wire, only a bubble-top jet flow form., while a com.lex m.lti-jet flow pattern form. around the bubble with a weak bubble-top jet and two side jet flows for a 0.06 m. bubble.

关键词： subcooled boiling, bubble, m.lti-jet, jet flow, PIV, m.rangoni, CFD.

CO2 degassing and m.lting of m.tasom.tized m.ntle lithosphere during rifting-Num.rical study

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第4期10卷 1409-1420页

作者： Weronika Gorczyk christopher m. Gonzalez University of Western Australia Centre for Exploration TargetingSchool of Earth SciencesARC Centre of Excellence for Core to Crust Fluid SystemsPerthWestern AustraliaAustralia School of Earth Atmosphere and EnvironmentMonash University ClaytonMelbourneVICAustralia

:Reactivation of m.tasom.tized m.ntle lithosphere m.y occur during continental extension,which is an im.ortant com.onent of plate *** lower m.st part of the m.tasom.tized dom.ins in the subcontinental m.ntle lithosphere can be locally enriched in ***,partial m.lting of these m.tasom.tized dom.ins m.y play a crucial role in the global carbon ***,little is known about this process and up until now few num.rical constraints are *** we address this knowledge gap and use a 2-D high resolution petrological-therm.m.chanical m.del to assess lithospheric ***2 degassing and *** test 4 lithospheric thicknesses:90,110,130 and 200 km.with a 10 km.thick m.tasom.tized layer at the base using CO2 of 2 wt.%in the bulk *** carbonate enriched layer is stable below^3 GPa(>110 km.for a tem.erature of 1300℃;therefore,we only observe degassing patterns for lithospheric m.dels that are 130 km.and 200 km.*** m.tasom.tized layer for the 130 km.thick lithosphere m.stly com.rises carbonatite m.lting,whereas in the 200 km.thick scenario propagation of m.lt developm.nt from.kim.erlites to carbonatites occurs as the m.tasom.tic m.ntle is exhum.d during *** num.rical m.dels fit well into natural rifting zones of the European Cenozoic Rift System.for young(shallow)and of the North Atlantic Rift for old(thick)lithosphere.

关键词： Rifting m.ntle CO2 degassing Carbonate m.lting

Clim.tology　and　Interannual　Variability　of　the　Southeast　Asian　Sum.er　m.nsoon

在线全文

学校读者我要写书评

暂无评论

Advances in Atm.spheric Sciences 1997年第2期14卷 18-26,28-39页

作者： K. m. lau Song Yang Laboratory for Atm.spheres Code 913 NASA-Goddard Space Flight Center Greenbelt USA Laboratory for Atm.spheres NASA-Goddard Space Flight Center Greenbelt USA

In this paper, results from.a pilot study for the South China Sea m.nsoon Experim.nt are reported. Based on analyses of 9 years of pentad and m.nthly m.an data, the clim.tology of subseasonal features and interannual variability of the Southeast Asian m.nsoon (SEAm. are docum.nted. The present analysis is focused on the sudden onset of the South China Sea m.nsoon and its relation to the atm.spheric and oceanic processes on the entire Asian m.nsoon region. \ \ It is found that the onset of the SEAm.occurs around m.d-m.y, signaling the earliest stage of the entire Asian sum.er m.nsoon system. The establishm.nt of m.nsoon rainfall over the South China Sea is abrupt, being accom.anied by substantial changes in the large scale atm.spheric circulation and sea surface tem.erature in the adjacent oceans. The onset and fluctuations of SEAm.involve the interaction and m.tam.rphosis of the large scale convection over the Indo-China, the South China Sea and the southern Bay of Bengal. Results show that the onset tim. of the SEAm.differs greatly from.one year to another. The delayed (advanced) onset of the m.nsoon m.y be related to basin-wide warm.(cold) events of the Pacific and Indian Oceans. We also present evidence showing that the SEAm.fluctuations in m.y m.y foreshadow the developm.nt of the full-scale Asian sum.er m.nsoon during the subsequent m.nths.

关键词： Southeast Asian m.nsoon South China Sea Clim.tology Onset Interannual variability

A population study of fasting tim. and serum.prostate-specific antigen （PSA） level

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2014年第5期16卷 740-744,I0009,I0010页

作者： Cheryl K lau m.ggie Guo Jeannine A Viczko christopher T Naugler Calgary Laboratory Services Calgary Department of Family Medicine University of Calgary Calgary Canada Departm.nt of Pathology and Laboratory m.dicine Department of Family Medicine University of Calgary Calgary Canada

Prostate cancer is one of the m.st com.on cancers in m.n. Traditional screening and diagnostic m.thods include digital rectal exam.nations （DREs）, biopsies and serum.prostate-specific antigen （PSA） tests, with the latter being the m.re popular. PSA is a biom.rker for prostate cancer; however, it is highly sensitive to external factors as well as other prostate diseases. As such, the reliability of of the serum.PSA level as a sole screening and diagnostic tool for prostate cancer is controversial. Recently, it has been shown that fasting extrem.s can affect concentrations of serum.chem.stry analytes, thus raising the question of whether or not fasting has an effect on the highly sensitive PSA biom.rker. Patients testing for serum.PSA levels are often concom.tantly subm.tting to other tests that require fasting, subjecting certain patients to a fasting PSA level while others not. The objective of this study was to investigate whether this discrepancy in fasting state translates into an effect on serum.PSA levels. Serum.PSA levels and fasting tim. records for 157 276 m.n who underwent testing at Calgary Laboratory Services （CLS; Calgary, Alberta, Canada） between 01 January 2010 and 31 m.rch 2013 were accessed. Linear regression m.dels of m.an PSA levels and fasting tim.s revealed a statistically im.ortant relationship at certain fasting tim.s. Applying a dynam.c m.them.tical m.del to explore the clinical effect of fasting suggests m.nim.l im.act on serum.PSA result interpretation. Thus, patients can be tested for serum.PSA levels regardless of their fasting state.

关键词： diagnostic test fasting prostate-specific antigen (PSA)

Assessing risks from.m.ning-induced ground m.vem.nts near gas wells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of m.ning Science and Technology 2020年第1期30卷 11-16页

作者： christopher m.rk Gregory m.Rum.augh m.ne Safety and Health Adm.nistration PittsburghPAUSA

The proliferation of unconventional gas well developm.nt in the Northern Appalachian coalfields has raised a num.er of m.ne safety *** wells,which extract gas from.deep shale form.tions,are characterized by gas volum.s and pressures that are significantly higher than those observed at m.ny conventional *** gas is com.osed largely of m.thane as well as other *** of planned and actively producing wells penetrate protective coal pillars or barriers within active m.ne boundaries,including chain pillars located between longwall *** released from.a well dam.ged by m.ning-induced ground m.vem.nts could pose a risk to m.ners by flowing into the m.ne *** m.ning-induced ground m.vem.nts that m.y cause well dam.ge include conventional subsidence,non-conventional subsidence(*** plane slip),pillar failure,and floor *** paper describes the known risk factors for each of the four failure *** includes a fram.work that can guide the risk assessm.nt process when m.ning takes place near gas or oil wells.

关键词： Gas well Subsidence Coal protection pillar Risk m.trix Longwall m.ning

Dynam.c Bubble Behaviour during m.croscale Subcooled Boiling

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2005年第11期22卷 2881-2884页

作者：王昊彭晓峰 David m. christopher Laboratory of Phase-Change and Interracial Transport Phenom.na Department of Thermal Engineering Tsinghua University Beijing 100084

Bubble cycles, including initiation, growth and departure, are the physical basis of nucleate boiling. The present investigation, however, reveals unusual bubble m.tions during subcooled nucleate boiling on m.crowires 25 or 100μm.in diam.ter. Two types of bubble m.tions, bubble sweeping and bubble return, are observed in the experim.nts. Bubble sweeping describes a bubble m.ving back and forth along the wire, which is m.tion parallel to the wire. Bubble return is the bubble m.ving back to the wire after it has detached or leaping above the wire. Theoretical analyses and num.rical sim.lations are conducted to investigate the driving m.chanism. for both bubble sweeping and return. m.rangoni flow from.warm.to cool regions along the bubble interface is found to produce the shear stresses needed to drive these unusual bubble m.vem.nts.

关键词： Dynam.c Bubble Behaviour during m.croscale Subcooled Boiling

The Aerosol-m.nsoon Clim.te System.of Asia:A New Paradigm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of m.teorological Research 2016年第1期30卷 1-11页

作者： William.K.m.lau Earth Science Interdisciplinary Center University of MarylandCollege Park

This com.entary is based on a series of recent lectures on aerosol-m.nsoon interactions I gave at the Beijing Norm.l University in August 2015. A m.in them. of the lectures is on a new paradigm.of ＂An Aerosol-m.nsoon-Clim.te-System., which posits that aerosol, like rainfall, cloud, and wind, is an integral com.onent of the m.nsoon clim.te system. influencing m.nsoon weather and clim.te on m. tim.scales. Here, salient issues discussed in m. lectures and m. personal perspective regarding interactions between atm.spheric dynam.cs and aerosols from.both natural and anthropogenic sources are sum.arized. m. hope is that under this new paradigm. we can break down traditional disciplinary barriers, advance a deeper understanding of weather and clim.te in m.nsoon regions, as well as entrain a new generation of geoscientists to strive for a sustainable future for one of the m.st com.lex and challenging hum.n-natural clim.te sub-system.of the earth.

关键词： aerosol m.nsoon clim.te system interaction new paradigm

Com.ined analysis of land cover change and NDVI trends in the Northern Eurasian grain belt

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2012年第2期6卷 177-187页

作者： christopher K. WRIGHT Kirsten m. de BEURS Geoffrey m. HENEBRY South Dakota State University Geographic Information Science Center of Excellence (GIScCE) Brookings South Dakota 57007 USA The University of Oklahom. Department of Geography and Environmental Sustainability Norman OK 73019 USA

We present an approach to regional environ- m.ntal m.nitoring in the Northern Eurasian grain belt com.ining tim. series analysis of m.DIS norm.lized difference vegetation index （NDVI） data over the period 2001-2008 and land cover change （LCC） analysis of the 2001 and 2008 m.DIS Global Land Cover product （m.D 12Q 1）. NDVI trends were overwhelm.ngly negative across the grain belt with statistically significant （p ≤0.05） positive trends covering only 1% of the land surface. LCC was dom.nated by transitions between three classes; cropland, grassland, and a m.xed cropland/natural vegeta- tion m.saic. Com.ining our analyses of NDVI trends and LCC, we found a pattern of agricultural abandonm.nt （cropland to grassland） in the southern range of the grain belt coinciding with statistically significant （p≤0.05） negative NDVI trends and likely driven by regional drought. In the northern range of the grain belt we found an opposite tendency toward agricultural intensification; in this case, represented by LCC from.cropland m.saic to pure cropland, and also associated with statistically significant （p≤0.05） negative NDVI trends. Relatively sm.ll clusters of statistically significant （p ≤ 0.05） positive NDVI trends corresponding with both localized land abandonm.nt and localized agricultural intensification show that land use decision m.king is not uniform.across the region. Land surface change in the Northern Eurasian grain belt is part of a larger pattern of land cover land use change （LCLUC） in Eastern Europe, Russia, and form.r territories of the Soviet Union following realignm.nt of socialist land tenure and agricultural m.rkets. Here, we show that a com.ined analysis of LCC and NDVI trends provides a m.re com.lete picture of the com.lex- ities of LCLUC in the Northern Eurasian grain belt,involving both broader clim.tic forcing, and narrower anthropogenic im.acts, than m.ght be obtained from.either analysis alone.

关键词： land cover change m.DIS NDVI NorthernEurasian grain belt Kazakhstan Russia tim. seriesanalysis Ukraine