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4D imaging of void nucleation,growth,and coalescence from large and small inclusions in steel under tensile deformation

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journal of Materials Science & Technology 2022年第28期123卷 168-176页

作者： Yi Guo Timothy L.Burnett Samuel A.McDonald Michael Daly Andrew H.Sherry Philip j.withers Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Henry Royce Institute Department of MaterialsUniversity of ManchesterM139PLUK European Synchrotron Radiation Facility(ESRF) 6 rue J Horowitz38000 GrenobleFrance National Nuclear Laboratory Chadwick HouseBirchwood ParkWarringtonWA36AEUK

Samples of SA508 grade 3 nuclear pressure vessel ferritic steel were subjected to tensile straining whilst being simultaneously imaged in 3D in real time using high resolution,high frame rate time-lapse synchrotron computed tomography(CT).This enabled direct observation of void development from nucleation,through growth to coalescence and final failure validating many inferences made post-mortem or by theoretical models,as well as raising new *** sparse,large inclusions were found to nucleate voids at essentially zero plastic strain(consistent with zero interfacial strength);these became increasingly elongated with *** contrast,a high density of small spherical voids were found to nucleate from the sub-micron cementite particles at larger strains(>200%)only in the centre of the necked(high triaxiality)*** interfacial strength approaching 2100 MPa was inferred and soon after their nucleation,these small voids coalesce to form internal microcracks that lead to the final failure of the *** surprisingly,under these conditions of generally low triaxial constraint the large voids are simply cut across and appear to play no significant role in determining the final *** implications of these results are discussed in terms of ductile fracture behaviour and the Gurson model for ductile fracture.

关键词： Void growth Ductile fracture Synchrotron X-ray tomography 4D imaging Bainitic steel

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Recurrent gene flow between Neanderthals and modern humans over the past 200,000 years

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四川生理科学杂志 2024年第7期46卷 1621-1621页

作者： Akey, joshua M Li, Liming Comi, Troy j Bierman, rob F Department of Medical Genetics and Developmental Biology School of Medicine The Key Laboratory of Developmental Genes and Human Diseases Ministry of Education Southeast University Nanjing 210009 China The Lewis-Sigler Institute for Integrative Genomics Princeton University Princeton NJ 08540 USA The Lewis-Sigler Institute for Integrative Genomics Princeton University Princeton NJ 08540 USA

Although it is well known that the ancestors of modern humans and Neanderthals admixed,the effects of gene flow on the Neanderthal genome are not well *** develop methods to estimate the amount of human-introgressed s... 详细信息

关键词： flow modern apply

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Compressive property and energy absorption characteristic of interconnected porous Mg-Zn-Y alloys with adjusting Y addition

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journal of Magnesium and Alloys 2024年第1期12卷 171-185页

作者： j.A.Liu S.j.Liu B.Wang W.B.Sun X.j.Liu Z.W.Han College of Materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of Bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China Weihai Institute for Bionics-jilin University Weihai 264205PR China

In this study,interconnected porous Mg-2Zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous Mg-Zn-Y and describe the details of the second *** tests were performed at room temperature(rt),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different Mg-Zn-Y ternary phases appear:I-phase(Mg_(3)Zn_(6)Y),W-phase(Mg_(3)Zn_(3)Y_(2)),and LPSO phase(Mg_(12)ZnY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 Mj/m^(3)to 10.97 Mj/m^(3)at rt,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous Mg-Zn-Y are altered by the testing *** compressive strength and energy absorption capacity of the porous Mg-Zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic

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Expansions for the Distribution and the Maximum from Distributions with an Asymptotically Gamma Tail When a Trend Is Present

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Acta Mathematica Sinica,English Series 2015年第3期31卷 526-542页

作者： Christopher S.withers Saralees NADARAjAH Industrial Research Limited University of Manchester

We give expansions about the Gumbel distribution in inverse powers of n and logn for Mn, the maximum of a sample size n or n ＋ 1 when the j-th observation is μ（j/n）＋ ej, μ is any smooth trend flmction and the residuals {ej} are independent and identically distributed with P（e〉r）≈exp（-δx）x^do ∑k=1 ∞ckx^-kβ as -x→∞. We illustrate practical value of the expansions using simulated data sets.

关键词： Bell polynomials expansions exponential and gamma tails Gumbel maximum trend

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An Investigation of Freezing of Supercooled Water on Anti-Freeze Protein Modified Surfaces

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journal of Bionic Engineering 2013年第2期10卷 139-147页

作者： Thibaut V j Charpentier Anne Neville Paul Millner rob Hewson Ardian Morina Institute of Engineering Thermofluids Surfaces and Interfaces (iETSI) Mechanical Engineering University of Leeds LS2 9JT Leeds UK

This work investigates how functionalization of aluminium surfaces with natural type III Anti-Freeze Protein （AFP） affects the mechanism of heterogeneous ice nucleation. First the bulk ice nucleation properties of distilled water and aqueous solution of AFP were evaluated by differential scanning calorimetry. Then the modified surface was characterized by Secondary Ions Mass Spectroscopy （SIMS）, Fourier Transform InfraRed （FTIR） spectroscopy and contact angle measurement. Freezing experiments were then conducted in which water droplets underwent a slow controlled cooling. This study shows that compared to uncoated aluminium, the anti-freeze proteins functionalized surfaces exhibit a higher and narrower range of freezing temperature. It was found that these proteins that keep living organisms from freezing in cold environment act in the opposite way once immobilized on surfaces by promoting ice nucleation. Some suggestions regarding the mechanism of action of the observed phenomena were proposed based on the Classical Nucleation Theory （CNT）.

关键词： anti-freeze protein surface functionalization ice nucleation temperature ice-like monolayer

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Phosphorus recovery:a need for an integrated approach

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Ecosystem Health and Sustainability 2018年第2期4卷 22-32页

作者： Suriyanarayanan Sarvajayakesavalu Yonglong Lu Paul.j.A.withers Paulo Sergio Pavinato Gang Pan Pisit Chareonsudjai State Key Lab ofUrban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijingChina SCOPE(Scientific Committee on Problems of the Environment) BeijingChina Department of Water and Health Faculty of Life SciencesJSS Academy of Higher Education and Research(Deemed to be University)MysuruIndia School of Environment Natural Resources and GeographyBangor UniversityBangorUK "Luiz de Queiroz"College of Agriculture Department of Soil SdienceUniversity of Sao PauloPiracicabaBrazi School of Animal Ruraland Environmental SciencesNottingham Trent UniversityNottinghamUK Department of Environmental Science Faculty of ScienceKhonKaen UniversityKhonKaenThailand

Introduction:Phosphorus(P)is an essential element in food production.P consumption is increasing over the years due to increasing population and increasing demand for agricultural *** the agricultural P through the understanding of bioav ailability,transport,and runoff will maximize the soil productivity and minimize the environmental *** management in agriculture,governance,and lack of integrated international govern-ance need to be addressed to overcome the P scarcity *** and Discussions:This article is focusing one such efficient management of P resource addressing the major portion of phosphorus which is unnoticed in agricultural residues,manures,and other *** cost of phosphate fertilizer,a scarcity of high-quality phosphate rock(PR),and increasing surface water pollution are driving a need to accelerate the recovery and reuse of phosphorus(P)from various waste *** to recover P occur all along the open P cycle from mining to households to ***,P recovery as a regional and global strategy toward P sustainability and future food,bio energy,and water security are in its infancy because of a number of technological,socioeconomic,and institutional *** these constraints requires concerted colla boration between relevant stakeholders and an integrated approach combining successful business models with socioeconomic and institutional changes.

关键词： Phosphorus recovery and reuse phosphatic fertilizers depletion eutrophication

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Distributed Secondary Control Based on Dynamic Diffusion Algorithm for Current Sharing and Average Voltage Regulation in DC Microgrids

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journal of Modern Power Systems and Clean Energy 2024年第2期12卷 597-607页

作者： Dawei Liao Fei Gao Daniel j.Rogers Wentao Huang Dong Liu Houjun Tang Department of Electrical Engineering Shanghai Jiao Tong UniversityShanghaiChina Department of Engineering Science University of OxfordOxford OX12JDU.K. IEEE

This paper introduces a distributed secondary control scheme for achieving current sharing and average voltage regulation objectives in a DC *** proposed scheme employs a dynamic diffusion algorithm(DDA)instead of the consensus algorithm to enable distributed communication among *** help understand DDA,the relation of DDA and other diffusion algorithms is discussed in detail and its superiority is shown by comparison with diffusion and consensus ***,considering the discrete nature and different sampling time of the digital controller and communication network,a z-domain model of the entire DC microgrid is *** influence of communication and secondary control parameters on the system stability is *** on the established model,the tolerable communication rates are ***-time simulations conducted on the OPAL-rt platform validate the effectiveness of the proposed scheme,showcasing its advantages in terms of convergence speed and stability.

关键词： Cooperative control DC microgrid diffusion algorithm discrete-time modeling distributed secondary control

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Current Injection Provokes Rapid Expansion of the Guard Cell Cytosolic Volume and Triggers Ca^2＋ Signals

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Molecular Plant 2016年第3期9卷 471-480页

作者： Lena j. Voss Rainer Hedrich M. rob G. Roelfsema Molecular Plant Physiology and Biophysics Julius-von-Sachs Institute for Biosciences Biocenter Werzburg University Julius-von-Sachs-Platz 2 97082 Werzburg Germany

High-resolution microscopy opens the door for detailed single-cell studies with fluorescent reporter dyes and proteins. We used a confocal spinning disc microscope to monitor fluorescent dyes and the fluorescent protein Venus in tobacco and Arabidopsis guard cells. Multi-barreled microelectrodes were used to inject dyes and apply voltage pulses, which provoke transient rises in the cytosolic Ca^2＋ level. Voltage pulses also caused changes in the distribution of Lucifer Yellow and Venus, which pointed to a reversible increase of guard cell cytosolic volume. The dynamic cytosolic volume changes turned out to be provoked by current injection of ions. A reduction of the clamp current, by blocking K^＋ uptake channels with Cs^＋, strongly suppressed the cytosolic volume changes. Cs^＋ not only inhibited the expansion of the cytosol, but also inhibited hyperpolarization-induced elevations of the cytosolic Ca^2＋ concentration. A complete loss of voltage-induced Ca^2＋ signals occurred when Ca^2＋-permeable plasma membrane channels were simultaneously blocked with La^3＋. This shows that two mechanisms cause hyperpolarization-induced elevation of the cytosolic Ca^2＋-concentration：（i） activation of voltage-dependent Ca^2＋-permeable channels, （ii） osmotically induced expansion of the cytosol, which leads to a release of Ca^2＋ from intracellular stores.

关键词： guard cell cytosolic Ca^2+ cytosolic volume voltage clamp current injection ion channel

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用被动地震监测确定切割注入裂缝的发育

用被动地震监测确定切割注入裂缝的发育

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美国勘探地球物理学家学会第66届年会

作者： rob.rt j．withers Shirley Rieven 高林 ARCO Exploration and Production Technology Massachusetts Institute of Technology

1993年底,大约400万1b模拟废弃固体物质被注入到得克萨斯jasper附近4500ft深度处的下Frio砂岩中。随后在5d时间内记录了2400多个地震事件。注入分四步进行,一步是压裂,其它三步都是固体物质注入,每步注入量相等,持续时间都为24h左右。...

1993年底,大约400万1b模拟废弃固体物质被注入到得克萨斯jasper附近4500ft深度处的下Frio砂岩中。随后在5d时间内记录了2400多个地震事件。注入分四步进行,一步是压裂,其它三步都是固体物质注入,每步注入量相等,持续时间都为24h左右。本文概述了地震特征在不同位置和不同时间的变化。在注入期间引发的地震在空间和时间上的分布是复杂的,它不同于脆性介质简单断裂的预期特征。我们认为,将充满泥浆的固体物质间歇式注入软地层可通过多种机制引起断裂。地震事件的发生时间和强度表明,在裂缝重新膨胀期间,裂缝系统中贮存了能量,能量聚集达到顶峰时发生大的地震事件,破裂处的裂缝迅速增大。注入的晚期阶段,在远离主裂缝轴向位置处只有较少且较小的事件发生,晚期的这些事件从400ft深处的裂缝开始朝注入井偏移。它们可能是因流体压力效应引起的剪切断裂所致。

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Reduction of epinephrine in the lumbar spinal cord following repetitive blast-induced traumatic brain injury in rats

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Neural Regeneration Research 2024年第7期19卷 1548-1552页

作者： Shigeharu Tsuda Mustafa Golam jiamei Hou Kevin K.W.Wang Floyd j.Thompson Prodip Bose Brain Rehabilitation Research Center Malcom Randall VA Medical CenterNorth Florida/South Georgia Veterans Health SystemGainesvilleFLUSA Department of Anesthesiology College of MedicineUniversity of FloridaGainesvilleFLUSA Department of Emergency Medicine University of FloridaGainesvilleFLUSA Department of Neuroscience University of FloridaGainesvilleFLUSA Department of Neurology University of FloridaGainesvilleFLUSA

Traumatic brain inju ry-induced unfavorable outcomes in human patients have independently been associated with dysregulated levels of monoamines,especially epinephrine,although few preclinical studies have examined the epinephrine level in the central nervous system after traumatic brain *** has been shown to regulate the activities of spinal motoneurons as well as increase the heart rate,blood pressure,and blood flow to the hindlimb ***,the purpose of the present study was to determine the impact of repeated blast-induced traumatic brain injury on the epinephrine levels in seve ral function-s pecific central nervous system regions in *** three repeated blast injuries at 3-day intervals,the hippocampus,motor cortex,locus coeruleus,vestibular nuclei,and lumbar spinal cord were harvested at post-injury day eight and processed for epinephrine assays using a high-sensitive electrochemical detector cou pled with high-performance liquid *** results showed that the epinephrine levels were significantly decreased in the lumbar spinal cord tissues of blast-induced traumatic brain injury animals compared to the levels detected in age-and sex-matched sham *** other function-specific central nervous system regions,although the epinephrine levels were slightly altered following blast-induced tra u matic brain injury,they were not statistically *** results suggest that blast injury-induced significant downregulation of epinephrine in the lumbar spinal cord could negatively impact the motor and cardiovascular *** is the first repo rt to show altered epinephrine levels in the spinal cord following repetitive mild blast-induced traumatic brain injury.

关键词： balance blood flow cardiovascular system central nervous system epinephrine ischemic damage lumbar spinal cord muscle tone repeated blast spasticity traumatic brain injury

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