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Classifying forest inventory data into species-based forest community types at broad extents： exploring tradeoffs among supervised and unsupervised approaches

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Forest Ecosystems 2018年第1期5卷 91-107页

作者： jennifer k.costanza don faber-langendoen john w.coulston david n.wear Department of Forestry and Environmental Resources North C arolina State University3041 Cornwalis RdResearch Triangle ParkRaleighNC 27709USA NatureServe 4600 N.Fairfax Dr7th FloorArlingtonVA 22203USA Southern Research Station USDA Forest ServiceBlacksburgVAUSA Southern Research Station USDA Forest ServiceRaleighNCUSA

Background： Knowledge of the different kinds of tree communities that currently exist can provide a baseline for assessing the ecological attributes of forests and monitoring future changes. Forest inventory data can facilitate the development of this baseline knowledge across broad extents, but they first must be classified into forest community types. Here, we compared three alternative classifications across the United States using data from over 117,000 U.S. Department of Agriculture Forest Service Forest Inventory and Analysis （FIA） plots. Methods： Each plot had three forest community type labels：（1）＂FIA＂ types were assigned by the FIA program using a supervised method; （2）＂USNVC＂ types were assigned via a key based on the U.S. National Vegetation Classification; （3）＂empirical＂ types resulted from unsupervised clustering of tree species information. We assessed the degree to which analog classes occurred among classifications, compared indicator species values, and used random forest models to determine how well the classifications could be predicted using environmental variables. Results： The classifications generated groups of classes that had broadly similar distributions, but often there was no one-to-one analog across the classifications. The Iongleaf pine forest community type stood out as the exception： it was the only class with strong analogs across all classifications. Analogs were most lacking for forest community types with species that occurred across a range of geographic and environmental conditions, such as Ioblolly pine types, indicator species metrics were generally high for the USNVC, suggesting that LJSNVC classes are floristically well-defined. The empirical classification was best predicted by environmental variables. The most important predictors differed slightly but were broadly similar across all classifications, and included slope, amount of forest in the surrounding landscape, average minimum temperature, and other climate variab

关键词： Big data Correspondence analysis Dominant species Forest communities Global change,Hierarchical classification Indicator species Random forests Species assemblages

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Electronictization-A Foundation for Grid Modernization

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Chinese Journal of Electrical Engineering 2015年第1期1卷 1-8页

作者： don Tan IEEE Power Electronics Society New JerseyUSA

Smart grid is the flag under which the US DoE has been mobilizing efforts to modernize the *** is the first step towards a smart modern *** is a process that transforms the grid from electrical and electromechanical(EE)to electronic,electrical and electromechanical(EEE),laying down the very basic foundation for the modern *** things grid connected(ATGC)has five groups of essential hardware:1)Grid interface(smart)inverters;2)Hardware for flexible AC transmissions;3)Intelligent electronic power transformers(grid scale);4)Solid-state circuit breaker,current limiters,smart fuses and sensors;and 5)Multi-port bidirectional power&control *** and deployment of ATGC will be a grassroots drive to transform the grid from an old passive technology to a new active technology based on electronic power transmission,distribution,processing and *** modernization represents a win-win-win situation for the environment(Government),consumers,and grid owners/operators.

关键词： Grid modernization electronictization fractal grid structure energy system resiliency fault management fault isolation renewable energy integration all things grid connected

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Approximate equivalence in von Neumann algebras

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Science China Mathematics 2005年第2期48卷 239-247页

作者： DING Huiru don Hadwin Department of Mathematics University of New HampshireDurhamNH03824USA Department of MathematicsUniversity of New HampshireDurhamNH03824USA

One formulation of D. Voiculescu's theorem on approximate unitary equivalence is that two unital representations π and ρ of a separable C*-algebra are approximately unitarily equivalent if and only if rank οπ = rank ορ. We study the analog when the ranges of π and ρ are contained in a von Neumann algebra R, the unitaries inducing the approximate equivalence must come from R, and 'rank' is replaced with 'R -rank' (defined as the Murray-von Neumann equivalence of the range projection).

关键词： approximate equivalence, R-rank.

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CFD investigation of dense phase pneumatic conveying at a pipeline enlargement

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Particuology 2012年第2期10卷 176-183页

作者： don McGlinchey Andrew Cowell Ryan Crowe School of Engineering and Computing Glasgow Caledonian University Glasgow Scotland UK

The practice of stepping a conveying line is not new and there are many examples in industry; however, the details of the flow behaviour at the step have not been extensively studied. Three step geometries were modelled： an ＇abrupt＇ step and two ＇gradual＇ step-up geometries from a pipe bore of 75-100 ram. The flow behaviour of a single plug of material passing through these geometries was investigated using the ＇Eulerian＇ CFD model from Fluent. Solids volume fractions were recorded at 0.01 s time steps at several point locations, and visualised throughout the pipe.

关键词： Pneumatic conveyingStepped pipelinePlug flowCFD

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Theory of phonon-modulated electron spin relaxation time based on the projection reduction method

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Chinese Physics B 2014年第8期23卷 436-443页

作者： Nam Lyong Kang Sang don Choi Department of Applied Nanoscience Pusan National University Department of Physics Kyungpook National University

This paper introduces a new method for a formula for electron spin relaxation time of a system of electrons interacting with phonons through phonon-modulated spin-orbit coupling using the projection-reduction method. The phonon absorption and emission processes as well as the photon absorption and emission processes in all electron transition processes can be explained in an organized manner, and the result can be represented in a diagram that can provide intuition for the quantum dynamics of electrons in a solid. The temperature （T） dependence of electron spin relaxation times （T1） in silicon is T1 ∝ T-1.07 at low temperatures and T1 ∝ T-3.3 at high temperatures for acoustic deformation constant Pad = 1.4 × 10^7 eV and optical deformation constant Pod = 4.0 × 10^17 eV/m. This means that electrons are scattered by the acoustic deformation phonons at low temperatures and optical deformation phonons at high temperatures, respectively. The magnetic field （B） dependence of the relaxation times is T1 ∝ B-2.7 at 100 K and T1 ∝ B-2.3 at 150 K, which nearly agree with the result of Yafet, T1 ∝ B-3.0- B -2.5.

关键词： electron spin resonance spin-orbit coupling projection-reduction method phonon scattering

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The effects of indigenous prescribed fire on riparian vegetation in central California

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Ecological Processes 2013年第1期2卷 245-253页

作者： don L Hankins Department of Geography and Planning California State University-ChicoChicoCAUSA

Introduction:Fire has a long history,but little documented role,as a process in riparian *** millennia California Indians have applied fire to riparian ecosystems for a variety of purposes,but the effects of such fires on riparian vegetation are poorly known outside of traditional knowledge structures of indigenous ***:This study involved the seasonal application of fire based on traditional ecological knowledge versus alternate burn methods to assess fire effects on riparian vegetation in central ***:While the annual variation amongst treatments was not significant,the results of this study suggest that fall burns support higher overall richness and native species richness;spring burns yield a decrease in overall richness,but an increase in native species richness;and summer burns contribute to an initial decline in overall and native species *** evenness indices of treatments increase most with spring and summer ***:These findings are key to understanding the seasonal role of fire in managing native species in areas prone to non-native or other invasive *** research demonstrates the application of traditional ecological knowledge to facilitate an understanding of how prescribed fire could aid in the management and conservation of riparian ecosystems.

关键词： Riparian California Indian Fire Indigenous Traditional ecological knowledge

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Geomicrobiological processes in extreme environments： A review

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Episodes 2007年第3期30卷 202-216页

作者： Hailiang don BingsongYu Geomicrobiology Laboratory China University of Geosciences Beijing 100083 China. Department of Geology Miami University Oxford OH 450561 USA. Email： dongh@muohio.edu School of Earth Sciences China University of Geosciences Beijing 100083 China.

The last decade has seen an extraordinary growth of Geomicrobiology. Microorganisms have been studied in numerous extreme environments on Earth, ranging from crystalline rocks from the deep subsurface, ancient sedimentary rocks and hypersaline lakes, to dry deserts and deep-ocean hydrothermal vent systems. In light of this recent progress, we review several currently active research frontiers： deep continental subsurface micro- biology, microbial ecology in saline lakes, microbial formation of dolomite, geomicrobiology in dry deserts, fossil DNA and its use in recovery of paleoenviron- mental conditions, and geomicrobiology of oceans. Throughout this article we emphasize geomicrobiological processes in these extreme environments.

关键词：地理微生物学极端环境环境保护探险

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What can computational modeling offer for studying the Ca^(2+) dysregulation in Alzheimer's disease:current research and future directions

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Neural Regeneration Research 2018年第7期13卷 1156-1158页

作者： Jingyi Liang don Kulasiri Centre for Advanced Computational Solutions(C-fACS) Lincoln University

Ca^2＋ dysregulation is an early event observed in Alzheimer＇s disease（AD） patients preceding the presence of its clinical *** of neuronalCa^2＋ will cause synaptic loss and neuronal death,eventually leading to memory impairments and cognitive *** targetingCa^2＋ signaling pathways are potential therapeutic strategies against *** complicated interactions make it challenging and expensive to study the underlying mechanisms as to how Ca^2＋ signaling contributes to the pathogenesis of *** modeling offers new opportunities to study the signaling pathway and test proposed *** this mini-review,we present some computational approaches that have been used to study Ca^2＋ dysregulation of AD by simulating Ca^2＋signaling at various *** also pointed out the future directions that computational modeling can be done in studying the Ca^2＋ dysregulation in AD.

关键词： Alzheimer's disease amyloid-beta Ca^2+ hypothesis Ca^2+ dysregulation computational modeling computational neuroscience

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Universal C*-algebras Defined by Completely Bounded Unital Homomorphisms

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Acta Mathematica Sinica,English Series 2015年第12期31卷 1825-1844页

作者： Wen Hua QIAN don HADWIN Department of Mathematics East China University of Science and Technology Department of Mathematics and Statistics University of New Hampshire

Suppose A is a unital C＊-algebra and r *** this paper,we define a unital C＊-algebra C（cb）＊（A,r） and a completely bounded unital homomorphism αr：A → C（cb）＊（A,r）with the property that C（cb）＊（A,r）=C＊（αr（A））and,for every unital C＊-algebra B and every unital completely bounded homomorphism φ：A→ B,there is a（unique）unital ＊-homomorphism π：C（cb）＊（A,r）→B such thatφ=πoα*** prove that,if A is generated by a normal set {tλ：λ∈Λ},then C（cb）＊（A,r）is generated by the set {αr（tλ）：λ∈Λ}.By proving an equation of the norms of elements in a dense subset of C（cb）＊（A,r）we obtain that,if Β is a unital C＊-algebra that can be embedded into A,then C（cb）＊（B,r）can be naturally embedded into C（cb）＊（A,r）.We give characterizations of C（cb）＊（A,r）for some special situations and we conclude that C（cb）＊（A,r）will be ＂nice＂ when dim（A）≤ 2 and ＂quite complicated＂ when dim（A）≥ *** give a characterization of the relation between K-groups of A and K-groups of C（cb）＊（A,r）.We also define and study some analogous of C（cb）＊（A,r）.

关键词： Completely bounded unital homomorphisms universal C*-algebras K-groups

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A Bishop-Stone-Weierstrass Theorem for (M_2(C))~n

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Acta Mathematica Sinica,English Series 2013年第8期29卷 1515-1534页

作者： Qi Hui LI don HADWIN Department of Mathematics East China University of Science and Technology Department of Mathematics and Statistics University of New Hampshire

In this paper, we shall give an elementary proof of a Bishop–Stone–Weierstrass theorem for （M2（C））n with respect to its pure states. To be more precise, we shall show that the pure-state Bishop hull of a unital ... 详细信息

关键词： Bishop–Stone–Weierstrass theorem pure states C*-algebras

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