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Impact of rewilding,species introductions and climate change on the structure and function of the Yukon boreal forest ecosystem

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Integrative Zoology 2018年第2期13卷 123-138页

作者： Rudy BOONSTRA Stan BOUTIN thomas S.jung Charles J.KREBS Shawn TAYLOR Department of Biological Sciences University of Toronto ScarboroughTorontoOntarioCanada Department of Biological Sciences University of AlbertaEdmontonAlbertaCanada Department of Environment Government of YukonWhitehorseYukonCanada Department of Zoology University of British ColumbiaVancouverBritish ColumbiaCanada

Community and ecosystem changes are happening in the pristine boreal forest ecosystem of the Yukon for 2 ***,climate change is affecting the abiotic environment(temperature,rainfall and growing season)and driving changes in plant productivity and predator-prey ***,simultaneously change is occurring because of mammal species reintroductions and *** key ecological question is the impact these faunal changes will have on trophic *** productivity in the boreal forest is increasing because of climatic warming,but plant species composition is unlikely to change significantly during the next 50-100 *** 9-10-year population cycle of snowshoe hares will persist but could be reduced in amplitude if winter weather increases predator hunting *** rodents have increased in abundance because of increased vegetation *** ground squirrels have disappeared from the forest because of increased predator hunting efficiency associated with shrub *** have occurred for 2 reasons:human reintroductions of large ungulates and natural recolonization of mammals and birds extending their geographic *** deliberate rewilding of wood bison(Bison bison)and elk(Cervus canadensis)has changed the trophic structure of this boreal ecosystem very *** natural range expansion of mountain lions(Puma concolor),mule deer(Odocoileus hemionus)and American marten(Martes americana)should have few ecosystem *** potential changes will require long-term monitoring studies and experiments on a scale we rarely deem *** affected by climate change,species reintroductions and human alteration of habitats cannot remain stable and changes will be critically dependent on food web interactions.

关键词： community stability introduced species population cycles trophic dynamics

Preface to the Special Issue:Towards Improving Understanding and Prediction of Arctic Change and its Linkage with Eurasian Mid-latitude Weather and Climate

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Advances in Atmospheric Sciences 2018年第1期35卷 1-4页

作者： Xiangdong ZHANG thomas jung Muyin WANG Yong LUO Tido SEMMLER Andrew ORR International Arctic Research Center University of Alaska FairbanksFairbanks AK 99775USA Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchBremerhaven 27570Germany joint Institute for the Study of the Atmosphere and Ocean University of WashingtonSeattleWA 98115USA Center for Earth System Science Tsinghua UniversityBeijing 100084China British Antarctic Survey Cambridge CB3 0ETUK

The dramatic changes in the Arctic climate system during recent decades are one of the most prominent features of global climate *** most striking and fundamental characteristics are the amplified near-surface warming at a rate twice the global average since the mid 20th century(e.g.,Blunden and Arndt,2012;Huang et al.,2017),and the rapid

关键词： Preface to the Special Issue:Towards Improving Understanding and Prediction of Arctic Change and Its Linkage with Eurasian Mid-latitude Weather and Climate

Preface to the Special Issue on Antarctic Meteorology and Climate:Past,Present and Future

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Advances in Atmospheric Sciences 2020年第5期37卷 421-422页

作者： Jiping LIU David BROMWICH Dake CHEN Raul CORDERO thomas jung Marilyn RAPHAEL John TURNER Qinghua YANG Department of Atmospheric and Environmental Sciences University at AlbanyState University of New YorkAlbanyNY 12222USA Polar Meteorology Group Byrd Polar and Climate Research CenterThe Ohio State UniversityColumbusOH 43210USA State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyHangzhou 310012China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China Departamento de Física University of SantiagoSantiago 3493Chile Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchBremerhaven 27570Germany Institute of Environmental Physics University of BremenBremen 28359Germany Department of Geography University of California-Los AngelesLos AngelesCA 90095USA British Antarctic Survey Natural Environment Research CouncilCambridgeCB30ETUK School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China

The Antarctic,including the continent of Antarctica and the Southern Ocean,is a critically important part of the Earth *** in Antarctic meteorology and climate has always been a challenging *** and predicting weather patterns in the Antarctic are important for understanding their role in local-to-global processes and facilitating field studies and logistical operations in the Antarctic(e.g.,Walsh et al.,2018).Studies of climate change in the Antarctic are comparatively neglected compared to those of the ***,significant climate changes have occurred in the Antarctic in the past several decades,i.e.,a strong warming over the Antarctic Peninsula even with a recent minor cooling,a deepening of the Amundsen Sea low,a rapid warming of the upper ocean north of the circumpolar current,an increase of Antarctic sea ice since the late 1970s followed by a recent rapid decrease,and an accelerated ice loss from the Antarctic ice shelf/sheet since the late 1970s(e.g.,Turner et al.,2005;Raphael et al.,2016;Sallée,2018;Parkinson,2019;Rignot et al.,2019).Investigating recent climate change in the Antarctic and the underlying mechanisms are important for predicting future climate change and providing information to policymakers.

关键词： Antarctic warming meteorology

Albedo of Coastal Landfast Sea Ice in Prydz Bay,Antarctica:Observations and Parameterization

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Advances in Atmospheric Sciences 2016年第5期33卷 535-543页

作者： Qinghua YANG Jiping LIU Matti LEPPRANTA Qizhen SUN Rongbin LI Lin ZHANG thomas jung Ruibo LEI Zhanhai ZHANG Ming LI Jiechen ZHAO Jingjing CHENG Key Laboratory of Research on Marine Hazards Forecasting National Marine Environmental Forecasting CenterBeijing 100081 Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchBremerhaven 27570Germany State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 University of Helsinki Helsinki 00014Finland University of Bremen 28334Germany Key Laboratory for Polar Science of the State Oceanic Administration Polar Research Institute of ChinaShanghai 200136 National Center of Ocean Standards and Metrology Tianjin 300112

The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica（off Zhongshan Station）during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters（e.g., snow thickness, ice thickness, surface temperature, and air temperature） were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed,which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo.

关键词： Antarctic sea ice albedo observation parameterization

The H∞ Robust Stability and Performance Conditions for Uncertain Robot Manipulators

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IEEE/CAA Journal of Automatica Sinica 2025年第1期 270-272页

作者： Geun Il Song Hae Yeon Park jung Hoon Kim the Department of Electrical Engineering Pohang University of Science and Technology (POSTECH) the Department of Electrical Engineering Pohang University of Science and Technology (POSTECH) the Institute for Convergence Research and Education in Advanced Technology Yonsei University

Dear Editor,H∞This letter develops a new framework for the robust stability and performance conditions as well as the relevant controller synthesis with respect to uncertain robot *** often exist model uncertainties between the nominal model and the real robot manipulator and disturbances. Hence, dealing with their effects plays a crucial role in leading to high tracking performances, as discussed in [1]–[5].

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Study on durability of Pt supported on graphitized carbon under simulated start-up/shut-down conditions for polymer electrolyte membrane fuel cells

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Journal of Energy Chemistry 2018年第1期27卷 326-334页

作者： Won Suk jung Department of Chemical Engineering University of South CarolinaColumbiaSC 29208USA

The primary issue for the commercialization of proton exchange membrane fuel cell（PEMFC） is the carbon corrosion of support under start-up/shut-down conditions. In this study, we employ the nanostructured graphitized carbon induced by heat-treatment. The degree of graphitization starts to increase between 900 and 1300 ℃ as evidenced by the change of specific surface area, interlayer spacing, and ID/IG value. Pt nanoparticles are deposited on fresh carbon black（Pt/CB） and carbon heat-treated at 1700 ℃（Pt/HCB17） with similar particle size and distribution. Electrochemical characterization demonstrates that the Pt/HCB17 shows higher activity than the Pt/CB due to the inefficient microporous structure of amorphous carbon for the oxygen reduction reaction. An accelerating potential cycle between 1.0 and 1.5 V for the carbon corrosion is applied to examine durability at a single cell under the practical start-up/shutdown conditions. The Pt/HCB17 catalyst shows remarkable durability after 3000 potential cycles. The Pt/HCB17 catalyst exhibits a peak power density gain of 3%, while the Pt/CB catalyst shows 65% loss of the initial peak power density. As well, electrochemical surface area and mass activity of Pt/HCB17 catalyst are even more stable than those of the Pt/CB catalyst. Consequently, the high degree of graphitization is essential for the durability of fuel cells in practical start-up/shut-down conditions due to enhancing the strong interaction of Pt and π-bonds in graphitized carbon.

关键词： Polymer electrolyte membrane fuel ceils Membrane electrolyte assembly Carbon corrosion Start-up/shut-down Durability

Tolerating Permanent State Transition Faults in Asynchronous Sequential Machines

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Journal of Computer Science & Technology 2016年第5期31卷 1028-1037页

作者： jung-Min Yang School of Electronics Engineering Kyungpook National University Daegu 41566 Korea

Corrective control theory lays a novel foundation for the fault-tolerant control of asynchronous sequential machines. In this paper, we present a corrective control scheme for tolerating permanent state transition faults in the dynamics of asynchronous sequential machines. By a fault occurrence, the asynchronous machine may be stuck at a faulty state, not responding to the external input. We analyze the detectability of the considered faults and present the necessary and sufficient condition for the existence of a controller that overcomes any permanent transition faults. Fault tolerance is realized by using potential reachability and asynchronous mechanisms in the machine. A case study on an asynchronous counter is provided to illustrate the proposed fault detection and tolerance scheme.

关键词： asynchronous sequential machine corrective control permanent fault fault tolerance

Next High Performance and Low Power Flash Memory Package Structure

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Journal of Computer Science & Technology 2007年第4期22卷 515-520页

作者： jung-Hoon Lee ERI Control Instrumentation EngineeringGyeongSang National UniversityJinju660-701Korea

In general, NAND flash memory has advantages in low power consumption, storage capacity, and fast erase/write performance in contrast to NOR flash. But, main drawback of the NAND flash memory is the slow access time for random read operations. Therefore, we proposed the new NAND flash memory package for overcoming this major drawback. We present a high performance and low power NAND flash memory system with a dual cache memory. The proposed NAND flash package consists of two parts, i.e., an NAND flash memory module, and a dual cache module. The new NAND flash memory system can achieve dramatically higher performance and lower power consumption compared with any conventionM NAND-type flash memory module. Our results show that the proposed system can reduce about 78% of write operations into the flash memory cell and about 70% of read operations from the flash memory cell by using only additional 3KB cache space. This value represents high potential to achieve low power consumption and high performance gain.

关键词： flash memory NAND-type NOR-type memory localities buffer or cache memory

Asymptotic T_u-Toeplitzness of weighted composition operators on H^2

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Science China Mathematics 2018年第5期61卷 881-896页

作者： Sungeun jung Department of Mathematics Hankuk University of Foreign Studies

Given a unilateral forward shift S acting on a complex,separable,infinite dimensional Hilbert space H,an asymptotically S-Toeplitz operator is a bounded linear operator T on H satisfying that{S^(*n)T S^n}is convergent with respect to one of the topologies commonly used in the algebra of bounded linear operators on *** this paper,we study the asymptotic T_u-Toeplitzness of weighted composition operators on the Hardy space H^2,where u is a nonconstant inner function.

关键词： Toeplitz operator asymptotically S-Toeplitz operator weighted composition operator inner function