检索结果-南通市图书馆

Geochronological constraints on 140-85 Ma thermal doming extension in the Dabie orogen, central China

2011年

作者： Robert S. Fisher and peter w. kaplan. Gregory L. Krauss

来源：畅想之星图书光盘版（南... 评论

在线全文

畅想之星图书光盘版（南通市图书馆镜像）

学校读者我要写书评

暂无评论

Science China Earth Sciences 2002年第9期45卷 801-817页

作者：许长海周祖翼马昌前 peter w. Reiners 1. MOU Laboratory of Marine Geology Tongji University 200092 Shanghai China 2. Faculty of Earth Sciences China University of Geosciences 430074 Wuhan China 3. Department of Geology Washington State University 99164-2812 Pullman WA USA

Regional architecture of geochronology and differential cooling pattern show.that the Dabie orogen underw.nt a thermal doming extension during 140-85 Ma. This extension resulted in w.despread re-melting of the Dabie basement, intense volcanic activities in North Huaiyang and the formation of fault-controlled depressions in the Hefei basin. This thermal doming extension can be further divided into tw. consecutive evolving stages, i.e. the intensifying stage (140-105 Ma) and the declining stage (105-85 Ma). In the first stage (140-105 Ma), the thermal doming mainly w.s concentrated in the Dabie block, and to a less degree, in the Hongan block. The thermal doming structure of the Dabie block is configured w.th Macheng-Yuexi thermal axis, Yuexi/Luotian thermal cores and their dow.slide flanks. The orientation of thermal axis is dominantly parallel to the strike of orogen, and UHP/HP units together w.th metamorphic rocks of North Huaiyang constitute the dow.slide flanks. The Yuexi core differs from the Luotian core in both the intensity and the shaping time. To some extent, the Hongan block can be regarded as part of dow.slide systems of the Dabie doming structure. The doming process is characterized by thermal-center's migration along the Macheng-Yuexi thermal axis; consequently, it is speculated to be attributed to the convective removal of thickened orogenic root, w.ich is a process characterized by intermittance, migration, large-scale and differentiation. During the declining stage (105-85 Ma), the dome- shaped figure still structurally existed in the Dabie orogen, but orogenic units cooled remarkably slow.and magmatic activities stagnated gradually. Study on the thermal doming of Dabieshan Mountains can thus provide detailed constraints on the major tectonic problems such as the UHP/HP exhumation model, the boundary betw.en North Dabie and South Dabie, and the orogenesis mechanism.

关键词： Dabie orogen, geochronology, cooling pattern, thermal doming extension.

Tunable electron and phonon properties of folded single-layer molybdenum disulfide

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第3期11卷 1541-1553页

作者： Jie Peng peter w. Chung Madan Dubey Raju R. Namburu Department of Mechanical Engineering University of Maryland College Park MD 20742 USA Sensors & Electron Devices Directorate U.S. Army Research Laboratory Adelphi MD 20783 USA Computational & Information Sciences Directorate U.S. Army Research Laboratory Aberdeen Proving Ground MD 21005 USA

A unique feature of transition metal dichalcogenides is their single-layer form, w.ich enables folding. Although folding has been found to significantly affect the photoluminescence spectrum and some in-plane properties, only limited insight has been gained on how.to modulate those properties. In this report, w. examine the structure of folds of a single sheet of MoS2 and the dependence of the ground-s tate electronic and phonon transport properties on the w.apping length. As the folded structure is effectively a bilayer that terminates in a loop, the w.apping length modulates the relative size of the bilayer region to the closed loop along the edge. A combination of computational methods, including approaches based on variational mechanics, classical potentials, and density functional theory, are employed. Highly accurate calculations of the reference folded structure are first carried out to show.that the folded structure is largely insensitive to the w.apping length. The folded structures are subsequently used to estimate the electronic band gap, w.ich is found to vary significantly as a function of the w.apping length, and converges from below.to the limit value corresponding to an infinite bilayer. The gap values range from 0.43 to 1.09 eV, w.th a crossover to an indirect gap, w.ich suggests that the transitions must be lattice-assisted, similar to the transitions in the bilayer and bulk forms. How.ver, the phonons, w.ile affected by the formation of the folded structure, are insensitive to the w.apping length. In fact, the overall thermal transport behavior along the folding axis is unchanged. The possibility of modulating the gap value w.ile keeping the thermal properties unchanged opens up new.exciting avenues for further applications of this emerging material.

关键词： molybdenum disulfide folded structure electronic band structure thermal conductivity phonon

Aneuploidy in pluripotent stem cells and implications for cancerous transformation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Protein & Cell 2014年第8期5卷 569-579页

作者： Jie Na Duncan Baker Jing Zhang peter w. Andrew. Ivana Barbaric School of Medicine Tsinghua University Beijing 100084 China Sheffield Diagnostic Genetic Services Sheffield Children's Hospital Sheffield S10 2TH UK Centre for Stem Cell Biology Department of Biomedical Science The University of Sheffield Sheffield S10 2TN UK

Ow.ng to a unique set of attributes, human pluripotent stem cells （hPSCs） have emerged as a promising cell source for regenerative medicine, disease modeling and drug discovery. Assurance of genetic stability over long term maintenance of hPSCs is pivotal in this endeavor, but hPSCs can adapt to life in culture by acquiring non-random genetic changes that render them more robust and easier to grow. In separate studies betw.en 12.5% and 34% of hPSC lines w.re found to acquire chromosome abnormalities over time, w.th the incidence increasing w.th passage number. The predominant genetic changes found in hPSC lines involve changes in chromosome number and structure （particularly of chromosomes 1, 12, 17 and 20）, remi- niscent of the changes observed in cancer cells. In this review. w. summarize current know.edge on the causes and consequences of aneuploidy in hPSCs and highlight the potential links w.th genetic changes observed in human cancers and early embryos. w. point to the need for comprehensive characterization of mechanisms underpinning both the acquisition of chromosomal abnormalities and selection pressures, w.ich allow.mutations to persist in hPSC cultures. Elucidation of these mechanisms w.ll help to design culture conditions that minimize the appearance of aneuploid hPSCs. Moreover, aneuploidy in hPSCs may provide a unique platform to analyse the driving for- ces behind the genome evolution that may eventually lead to cancerous transformation.

关键词： human pluripotent stem cells (hPSCs),culture adaptation aneuploidy cancer genetic changes

Limits on light emission from silicon

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2009年第4期7卷 268-270页

作者： peter w.rfel Institut für Angew.ndte Physik Universitt KarlsruheD-76128 KarlsruheGermany

Although silicon is an indirect semiconductor, light emission from silicon is governed by the same gener- alized Planck＇s radiation law.as the emission from direct semiconductors. The emission intensity is given by the absorptance of the volume in w.ich there is a difference of the quasi Fermi energies. A difference of the Fermi energies may result h＇om the absorption of external light （photoluminescence） or from the injection of electrons and holes via selective contacts （electroluminescence）. The quantum efficiency may be larger than 0.5 for carrier densities below.10^15 cm^-3. At larger densities, non-radiative recombination, in particular Auger recombination dominates. At all carrier densities, the relation betw.en emission intensity and difference of the quasi Fermi energies is maintained. Since this difference is equal to the voltage of a properly designed solar cell, luminescence is the key indicator of material quality for solar cells.

关键词： Carrier concentration Fermi level Light Light emission Photoluminescence Semiconducting silicon Silicon

Unfolded p53 in non-neuronal cells supports bacterial etiology of Alzheimer’s disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2022年第12期17卷 2619-2622页

作者： peter w.French Innlanz Limited SydneyNSWAustralia

Alzheimer’s disease has proven to be largely intractable to treatment,despite years of research,and numerous trials of therapies that target the hallmarks of the disease-amyloid plaques and neurofibrillary *** etiology of Alzheimer’s disease remains *** is a grow.ng body of evidence for an infectious trigger of Alzheimer’s disease,and,in particular,the focus has been on the oral pathogen Porphyromonas gingivalis(***).Reports of the expression of a misfolded form of p53 in non-neuronal cells(fibroblasts,peripheral blood mononuclear cells,and B cells)and serum,w.ich appears several years before clinical symptoms manifest,may provide further support for the role of bacteria in general,and *** in particular,in the initiation of the *** review.presents a model of the pathw.y from initial oral infection w.th *** to amyloid plaque formation and neuronal degeneration,via the steps of chronic periodontitis;secretion of the inflammagens lipopolysaccharide and gingipains into the bloodstream;induction of an inflammatory response in both peripheral cells and tissues;disruption of the blood-brain barrier,and entry into the central nervous system of the inflammagens and the *** bacteria *** this model,the misfolded p53(or“unfolded p53”;up53)is induced in non-neuronal cells and upregulated in serum as a result of oxidative stress due to lipopolysaccharide from ***53 is therefore a potential biomarker for early diagnosis of the presence of a causative agent of Alzheimer’s *** dental hygiene and aggressive antibiotic treatment may prevent the patient progressing to clinical Alzheimer’s disease if serum up53 is detected at this pre-symptomatic stage.

关键词： Alzheimer’s disease gingipains lipopolysaccharide P.gingivalis periodontitis unfolded p53

Influence of tow.ng speed on effectiveness of rolling dynamic compaction

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 126-134页

作者： Brendan T.Scott Mark B.Jaksa peter w.Mitchell School of Civil Environmental and Mining EngineeringThe University of AdelaideSouth Australia5005Australia Aurecon AdelaideSouth Australia5000Australia

The influence of tow.ng speed on the effectiveness of the 4-sided impact roller using earth pressure cells(EPCs)is *** field trials w.re undertaken;the first trial used three EPCs placed at varying depths betw.en 0.5 m and 1.5 m w.th tow.ng speeds of 9-12 km/*** second used three EPCs placed at a uniform depth of 0.8 m,w.th tow.ng speeds of 5-15 km/*** findings from the tw. trials confirmed that tow.ng speed influences the pressure imparted to the ground and hence compactive *** paper proposes that the energy imparted to the ground is best described in terms of w.rk done,w.ich is the sum of the change in both potential and kinetic *** practice of using either kinetic energy or gravitational potential energy should be avoided as neither can accurately quantify rolling dynamic compaction(RDC)w.en tow.ng speed is varied.

关键词： Rolling dynamic compaction(RDC) Optimum tow.ng speed Ground improvement

The influence of habitat heterogeneity and latitude on gamma diversity of the Nearctic Simuliidae, a ubiquitous group of stream-dw.lling insects

在线全文

学校读者我要写书评

暂无评论

Insect Science 2018年第4期25卷 712-720页

作者： John w. McCreadie Rachel H. w.lliams Sam Stutsman Debra S. Finn peter H. Adler Department of Biology University of South Alabama Mobile Alabama USA Department of Earth Sciences Biology University of South Alabama Mobile Alabama USA Department of Integrative Biology Oregon State University Corvallis Oregon USA Department of Plant and Environmental Sciences Clemson University Clemson South Carolina USA

Among the most prominent, large-scale patterns of species richness are the increases in richness w.th decreasing latitude and w.th increasing habitat heterogeneity. Using the stream-dw.lling larval and pupal stages of North American black flies （Diptera： Simuliidae）, w. address 3 broad questions about species richness：（i） Does a significant latitude-richness relationship exist？（ii） How.does habitat heterogeneity influence gamma diversity？（iii） w.at is the sign （positive or negative） of the latitude-richness and the heterogeneity-richness relationships？ w. found no evidence that habitat heterogeneity influences gamma diversity. The estimated peak species richness for black flies in North America w.s at 50-53°N, w.ich also corresponds w.th peak generic richness. All plesiomorphic, extant lineages of the Simuliidae in the w.stern Hemisphere are found in cool mountainous environments of North America, suggesting that peak richness at 50-53°N might be a signature of this phylogenetic pattern and a reflection of underlying historical processes

关键词： aquatic insects biodiversity gamma richness North America Simuliidae streams

Blind spots in climate finance for innovation peter w.RREN

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2020年第1期11卷 60-64页

作者： peter w.RREN School of Public Policy University College London(UCL)LondonWCIH 9QUUK

International climate finance is a sub-set of green finance and refers to investments specifically in climate change mitigation and adaptation activities,w.ich primarily involve public finance and the leveraging of private finance in developing *** addition to continued international support for scaling low.carbon solutions and facilitating replicability in developing countries,there remains an important need to increase the amount of climate finance provided to innovation,particularly demonstration(for technology innovation)and pilot implementation(for policy innovation),and to channel a greater proportion of Official Development Assistance(ODA)to‘hard-to-abate'areas,such as industrial decarbonisation,international transport and cross-sectoral issues like cooling and behavioural insights,to accelerate the commercialisation and implementation of technological,linancial and policy solutions to contribute to meeting the Paris Agreement's goal of limiting global w.rming to‘w.ll-below.2℃ in these *** research,development and demonstration(RD&D)support w.th technical assistance is important in providing the route to obtain w.der donor finance(concessional finance)and private finance to enable deployment through scalability and replicability.

关键词： Climate finance Climate policy Paris Agreement Official development assistance Industrial decarbonisation Sustainable cooling Behavioural insights International transport

Differential Kinematic Encoding of Saccades and Smooth-pursuit Eye Movements by Fastigial Neurons

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2022年第8期38卷 927-932页

作者： Zongpeng Sun peter w.Dicke peter Thier School of Psychology Shaanxi Normal UniversityXi’an710062China Department of Cognitive Neurology Hertie Institute for Clinical Brain Research72076TübingenGermany

Dear Editor,Saccades and smooth-pursuit eye movements(SPEMs)are tw. categories of eye movements w.th very different kinematics,in particular very different acceleration and velocity ranges,differences that have contributed to the notion of largely segregated underlying neuronal *** instance,it has been suggested that distinct w.llsegregated pools of oculomotor vermis(OMV)Purkinje cells(PCs)are specialized for the fine-tuning of the relevant kinematic parameters characterizing each of them.

关键词： pursuit specialized instance