检索结果-南通市图书馆

Speculations on the mechanisms for the formation and breakup of supercontinents

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2013年第2期4卷 185-194页

作者： J.Brendan murphy R.Damian Nance Department of Earth Sciences.St.Francis Xavier University Antigonish.Nova Scotia B2G 2W5Canada Department of Geological Sciences Ohio UniversityAthensOH 45701USA

The supercontinent cycle has had a profound effect on the Earth＇s evolution since the Late Archean but our understanding of the forces responsible for its operation remains *** appear to form by two end-member processes：extroversion,in which the oceanic lithosphere surrounding the supercontinent（exterior ocean） is preferentially subducted（***）,and introversion in which the oceanic lithosphere formed between dispersing fragments of the previous supercontinent（interior ocean） is preferentially subducted（***）.Extroversion can be explained by ＂top-down＂ geodynamics, in which a supercontinent breaks up over a geoid high and amalgamates above a geoid low. Introversion,on the other hand,requires that the combined forces of slab-pull and ridge push（which operate in concert after supercontinent break-up） must be overcome in order to enable the previously dispersing continents to turn *** may begin when subduction zones are initiated along boundaries between the interior and exterior oceans and become trapped within the interior *** speculate that the reversal in continental motion required for introversion may be induced by slab avalanche events that trigger the rise of superplumes from the core-mantle boundary.

关键词： Supercontinent cycle Introversion Extroversion Pangea Rodinia Pannotia

Origins of the supercontinent cycle

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2013年第4期4卷 439-448页

作者： R.Damian Nance J.Brendan murphy Department of Geological Sciences.316 Clippinger Laboratories.Ohio University.Athens.OH 45701.USA Department of Earth Sciences st.Francis Xavier UniversityAntigonishNova Scotia B2G 2W5.Canada

The supercontinent cycle, by which Earth history is seen as having been punctuated by the episodic assembly and breakup of supercontinents, has influenced the rock record more than any other geologic phenomena, and its recognition is arguably the most important advance in Earth Science since plate tectonics. It documents fundamental aspects of the planet＇s interior dynamics and has charted the course of Earth＇s tectonic, climatic and biogeochemical evolution for billions of years. But while the widespread realization of the importance of supercontinents in Earth history is a relatively recent development, the supercontinent cycle was first proposed thirty years ago and episodicity in tectonic processes was recognized long before plate tectonics provided a potential explanation for its occurrence. With interest in the supercontinent cycle gaining momentum and the literature expanding rapidly, it is instructive to recall the historical context from which the concept developed. Here we examine the supercontinent cycle from this perspective by tracing its development from the early recognition of long-term epi- sodicity in tectonic processes, through the identification of tectonic cycles following the advent of plate tectonics, to the first realization that these phenomena were the manifestation of episodic superconti- nent assembly and breakup.

关键词： Supercontinent cyclePlate tectonicsTectonic episodicitySecular trends

BUCKLING LOADS AND EIGENFREQUENCIES OF A BRACED BEAM RESTING ON AN ELASTIC FOUNDATION

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2011年第6期24卷 510-518页

作者： Yin Zhang Yun Liu Peng Chen Kevin D murphy State Key Laboratory of-Nonlinear Mechanics （LN M） Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China Faculty of Information and Automation Kunming University of Science and Technology Kunming 650051 China Department of Civil Engineerning Guangdong Technical College of Water Resources and Electric Engineering Guangzhou 510635 China Department of Mechanical Engineering University of Connecticut Storrs CT 06269 USA

The eigenvalue problems of the buckling loads and natural frequencies of a braced beam on an elastic foundation are investigated. sented. The eigenvalues vary with the different The exact solutions for the eigenvalues are preparameters and are especially sensitive to the brace location. As the beam of a continuous system has infinite eigenvalues and these eigenvalues are influenced differently by a brace, the eigenvalues show rich variation patterns. Because these eigenvalues physically correspond to the structure buckling loads and natural frequencies, the study on the eigenvalues variation patterns can offer a design guidance of using a lateral brace of translation spring to strengthen the structure.

关键词： beam elastic foundation buckling eigenfrequency curve crossing curve veering

Natural Killer Cells:Biology and Clinical Use in Cancer Therapy

在线全文

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2004年第1期1卷 12-21页

作者： William H.D.Hallett William J.murphy Department of Microbiology and Immunology University of Nevada School of Medicine.University of Nevada.Reno.Reno.NV.USA.

Natural killer (NK) cells have the ability to mediate both bone marrow rejection and promote engraftment,as well as the ability to elicit potent anti-tumor *** the clinical results for these processes are still *** understanding of NK cell biology,from activating and inhibitory receptor functions to the role of NK cells in allogeneic transplantation,needs to be appreciated in order to draw out the clinical potential of NK *** of bone marrow cell (BMC) rejection are known to be dependant on inhibitory receptors specific for major histocompatibility complex (MHC) molecules and on activating receptors that have many potential *** modulation of activating and inhibitory receptors may hold the key to clinical success involving NK ***-clinical studies in mice have shown that different combinations of activating and inhibitory receptors on NK cells can reduce graft-versus-host disease (GVHD),promote engraftment,and provide superior graft-versus-tumor (GVT) *** clinical data have shown that the use of KIR-ligand incompatibility produces tremendous graft-versus-leukemia effect in patients with acute myeloid leukemia at high risk of *** review will attempt to be a synthesis of current knowledge concerning NK cells,their involvement in BMT,and their use as an immunotherapy for cancer and other hematologic *** & Molecular Immunology.2004;1(1):12-21.

关键词： NK cell BMT GVHD GVT

Effect of dilution gas composition on the evolution of graphite electrode characteristics in the spark gap switch

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2021年第6期23卷 74-82页

作者：戴宏宇李黎任帅郭景润宫鑫 Anthony Bruce murphy State Key Laboratory of Advanced Electromagnetic Engineering and Technology Key Laboratory of Pulsed Power Technology(Ministry of Education)School of Electrical and Electronic EngineeringHuazhong University of Science&TechnologyWuhan 430074People's Republic of China CSIRO Manufacturing Lindfield NSW 2070Australia

As the widely implemented electrode material,graphite has the characteristic of sublimation by the thermal shock of the switching arc,and the produced carbon vapor is easy to condense into carbon powders and deposit in the *** impact of the type of dilution gas in a mixture of20%oxygen and 80%dilution gas on the sublimation and oxidation characteristics of the graphite electrode is *** is found that when nitrogen dilution gas was replaced by argon,the heat flux to the electrodes decreased,which led to a 63%reduction of graphite *** the same time,the cooling rate of the arc was slower in argon,which promotes oxidation of the carbon *** residual solid carbon can be reduced by 70%–85%by using argon as the dilution ***,it is demonstrated that the stability and working life of the switch could be increased by appropriate selection of the dilution gas.

关键词： pulsed discharge graphite electrode thermal arc dilution gas electrode erosion

The role of organic electron donors in the initiation of BHAS base-induced coupling reactions between haloarenes and arenes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2019年第11期62卷 1425-1438页

作者： Andrew J.Smith Darren L.Poole John A.murphy Department of Pure and Applied Chemistry University of StrathclydeStrathclydeGlasgow G11XLUnited Kingdom Flexible Discovery Unit GlaxoSmithKline Medicines Research CentreStevenageSG12NYUnited Kingdom

Coupling reactions between haloarenes and arenes(including heteroarenes)that are conducted without added transition metals but in the presence of KOtBu or NaOtBu,have been a topic of great interest since their discovery in *** organic structures act as additives that assist these *** additives are converted into organic electron donors by the butoxide base and this leads to initiation of the coupling reactions,which proceed by radical chain *** review provides an overview of the initiation stages of these reactions.

关键词： organic electron donor potassium tert-butoxide electron transfer base-promoted homolytic aromatic substitution(BHAS) coupling benzyne

Cyclin-dependent kinase inhibitors in brain cancer:current state and future directions

在线全文

学校读者我要写书评

暂无评论

Cancer Drug Resistance 2020年第1期3卷 48-62页

作者： Viktorija Juric Brona murphy Department of Physiology and Medical Physics Royal College of Surgeons in IrelandDublin D02Ireland

Cyclin-dependent kinases(CDKs)are important regulatory enzymes in the normal physiological processes that drive cell-cycle transitions and regulate *** all cancers harbour genomic alterations that lead to the constitutive activation of CDKs,resulting in the proliferation of cancer *** inhibitors(CKIs)are currently in clinical use for the treatment of breast cancer,combined with endocrine *** this review,we describe the potential of CKIs for the treatment of cancer with specific focus on glioblastoma(GBM),the most common and aggressive primary brain tumour in *** intense effort to combat GBM with surgery,radiation and temozolomide chemotherapy,the median survival for patients is 15 months and the majority of patients experience disease recurrence within 6-8 months of treatment *** therapeutic approaches are urgently needed for both newly diagnosed and recurrent GBM *** this review,we summarise the current preclinical and clinical findings emphasising that CKIs could represent an exciting novel approach for GBM treatment.

关键词： Cyclin-dependent kinases cyclin-dependent kinase inhibitors gliomas glioblastoma clinical trials resistance

Crustacean parasites associated with hermit crabs from the western Mediterranean Sea,with first documentation of egg predation by the burrowing barnacle Trypetesa lampas(Cirripedia:Acrothoracica:Trypetesidae)

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2011年第1期6卷 13-27页

作者： Jason D.WILLIAMS Alejandra GALLARDO Angela E.murphy Department of Biology Hofstra UniversityHempsteadNYUSA

Parasitic isopods(family Bopyridae)and burrowing barnacles(family Trypetesidae)infesting hermit crabs were investigated from shallow subtidal collections made along the southeastern coast of Spain in 2009.A total of 713 specimens of Clibanarius erythropus(Latreille,1818)and 82 Calcinus tubularis(L.,1767)were *** shells and worm tubes inhabited by hermit crabs were collected by hand while snorkeling and were cracked to determine host species,size,sex and presence of *** species of bopyrid isopods were found on ***:the branchial parasite Bopyrissa fraiseii(Carayon,1943)and the abdominal parasite Parathelges cardonae Codreanu and Codreanu in Codreanu,*** all *** examined,Bopyrissa fraiseii was found on 0.6%of hermit crabs and *** was found on 0.3%.A redescription of *** is provided and the species is documented with light and scanning electron microscopy for the first *** Calcinus tubularis harbored parasitic isopods,but one specimen was parasitized by an unidentified rhizocephalan barnacle of the genus Septosaccus(1.2%).The burrowing barnacle Trypetesa lampas(Hancock,1849)was found associated with both hermit crab species and evidence of predation on host eggs by this barnacle is shown for the first *** lampas was found in 4.2%of the shells *** present study expands our knowledge of the parasite fauna of hermit crabs from the Mediterranean Sea and indicates that additional research is needed to determine the impact of trypetesid egg predators on hermit crab populations.

关键词： Bopyridae egg predator Isopoda parasitism Rhizocephala

An Unusual, Fangless Short-tailed Snake(Squamata, Serpentes, Homalopsidae) from Sumatra, Indonesia

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Herpetological Research 2013年第2期4卷 140-146页

作者： John C.murphy Harold K.VORIS Science and Education Field Museum

Two genera of fangless homalopsid snakes Brachyorrhos and Calamophis from eastern Indonesia have been described as basal members of the clade. A third genus belonging to this group from Sumatra, Indonesia is described here based upon morphology. Fangless homalopsid snakes share 19 dorsal scale rows at mid-body, fused dorsal scales above the cloaca, 5 to 7 upper labials, divided anal plate, divided subcaudals, 15-21 teeth on the dentary, frontal bone about 23% of skull length and other morphological characters that suggest they are related. All the three genera are known only from Indonesia. The new genus and species have a distinctive skull morphology with an absent premaxilla, a more depressed skull, and a larger eye than are present in Brachyorrhos.

关键词： Brachyorrhos Calamophis Karnsophis basal homalopsids skull osteology