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Biophysical and spectral characteristics of cool- and warm-season grasslands under three land management practices in Eastern Kansas

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Natural Resources Research 2000年第4期9卷 321-331页

作者： Guo, Xulin Price, Kevin P. Stiles, James M. Kansas Applied Remote Sensing Program (KARS) Department of Geography University of Kansas Lawrence KS 66045 2335 Irving Hill Road United States Radar Systems and Remote Sensing Laboratory (RSL) Department of Electrical Engineering and Computer Science University of Kansas Lawrence KS 66045 2335 Irving Hill Road United States Lawrence KS 66045 2335 Irving Hill Road United States

Grasslands are the largest of the Earth's four major vegetation types and are among the most agriculturally productive lands. Grassland management practices alter biophysical factors, such as plant species composition, soil structure and chemistry, and primary productivity. Large-scale changes in land management practices can have significant impacts on available natural resources, therefore impacting a regional socioeconomics. For these reasons, an improved understanding of the geographic distribution of changing land management practices and how these changes affect grassland biophysical characteristics of an area is critical to improve land use planning and practices. This study investigated the spectral characteristics, as measured using satellite remotely sensed data, of three land management practices [grazing, haying, and management under Conservation Reserve program (CRP)] on areas dominated by cool- and warm-season grasslands. The satellite imagery was acquired in May, July, and September in 1997 over Douglas County, Kansas. Biomass, vegetation cover, and species richness data were collected around the satellite overflight periods. Our results indicate that the biophysical characteristics and spectral reflectances are significantly different among the three management practices over cool- and warm-season grasslands. Interestingly, sites grazed by livestock had the highest species richness and the highest forb cover, although the total cover is almost the same as the other practices, and they have the highest near-infrared reflectance throughout the growing season. © 2000 International Association for Mathematical Geology.

关键词： Landsat Tallgrass prairie Thematic Mapper (TM)

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All-solid-state Cr:forsterite laser generating 14-fs pulses at 1.3 /spl mu/m

All-solid-state Cr:forsterite laser generating 14-fs pulses ...

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Conference on Lasers and Electro-Optics (CLEO)

作者： C. Chudoba J.G. Fujimoto F.P. Ippen H.A. Haus U. Morgner F.X. Kartner V. Scheurer G. Angelow T. Tschudi Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA USA High-Frequency and Qumiam Electronics Laboratory University of Karlsruhe Germany Institute for Applied Physics Darmstadt Germany

14-fs pulses at 1.3μm were generated by an all-solid-state, Kerr-lens mode-locked Crforsterite laser using double chirped mirrors. The spectral bandwidth (FWHM) was 250 mm with an 80 mW average power and 100 MHz repe... 详细信息

ISBN: (纸本)1557526346

关键词： Optical pulse generation Mirrors Power lasers Large Hadron Collider Chirp Power generation Bandwidth Laser beams Nitrogen Sputtering

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Design considerations for a multi-megawatt coaxial cavity gyrotron at 170 GHz

Design considerations for a multi-megawatt coaxial cavity gy...

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International Conference on Infrared and Millimeter Waves

作者： O. Dumbrajs Ch.T. Iatrou A.B. Pavelyev B. Piosczyk M. Thumm Department of Engineering Physics and Mathematics Helsinki University of Technology Espoo Finland Department of Electrical and Computer Engineering National and Technical University of Athens Athens Greece Institute of Applied Physics Russian Academy of Science Nizhny Novgorod Russia Forschungszentrum Karlsruhe Association EURATOM-FZK Institut für Hochleistungsimpuls und Mikrowellentechnik Eggenstein Germany

Some design considerations related to wall losses and mode competition in an ITER relevant coaxial cavity gyrotron are presented. New possibilities of heat redistribution and of reduction of mode competition by means ... 详细信息

关键词： Coaxial components Gyrotrons Voltage Conductors Q factor Radio frequency Mathematics physics computing Electromagnetic heating Corrugated surfaces

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Study of a Cr doped TiO/sub 2/ derived from sol-gel process for gas sensing

Study of a Cr doped TiO/sub 2/ derived from sol-gel process ...

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Conference on Optoelectronic and Microelectronic Materials and Devices

作者： J.M. Booth L. Nguyen C.J. Rix D.E. Mainwaring Y.X. Li W. Wlodarski S.H. Moslih S.P. Russo School of Electrical & Computer Systems Engineering RMIT University Melbourne Australia Departments of Appl. Chem. R. Melbourne Inst. of Technol. Vic. Australia Applied Physics RMIT University Melbourne Australia Department of Applied Chemistry RMIT University Melbourne Australia

ISBN: (纸本)0780366980

The sol-gel route to thin bimetallic oxide sensor films was studied in terms of the evolution of a viscoelastic Ti gel precursor containing occluded Cr. The influence of Cr:Ti atomic ratio and annealing temperature was related to the resultant microstructure, morphology and oxygen sensing response of the annealed thin films. It was shown that progressive increase in Cr content changed the Ti-O properties from a n-type to a p-type semiconductor film with a commensurate reversal in sensor response.

关键词： Chromium Temperature sensors Thin film sensors Annealing Viscosity Elasticity Microstructure Morphology Semiconductor thin films Semiconductor films

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Compact Compton Scattering X-Ray Source for Advanced Cancer Research

Compact Compton Scattering X-Ray Source for Advanced Cancer ...

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2000 25～(th) International Conference on Infrared and Millimeter Waves Conference Digest

作者： N.C.Luhmann Jr. J.E.Boggan G.Caryotakis F.V.Hartemann J.P.Heritage E.Landahl D.L.Matthews A.Norman T.Solberg A.Vlieks Department of Applied Science University of CaliforniaDavis Electrical and Computer EngineeringUniversity of CaliforniaDavis Department of Neurosurgery University of CaliforniaDavis Stanford Linear Accelerator Center Stanford University Lawrence Livermore National Laboratory University of California Radiation Oncology and Biomedical Physics UCLA

The combination of a high repetition rate(1 kHz),high power (TW-class,100fsec) Ti:sapphire laser and a high gradi-ent (≌75 MeV/m) . high brightness (ε≌3π-mm-mrad) photoinjector/electron ac-celerator(15-100 MeV,≌lnC per pulse)is predicted to produce high intensity (≌10 photons/sec),monoenergetic (<10% BW)X-rays tunable from 10 to 100keV .The small source size (a≌10μm)permits significant magnification (up to8x)to be employed in imaging applica-tions.

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Compact Compton scattering X-ray source for advanced cancer research

Compact Compton scattering X-ray source for advanced cancer ...

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International Conference on Infrared and Millimeter Waves

作者： N.C. Luhmann J.E. Boggan G. Caryotakis F.V. Hartemann J.P. Heritage E. Landadl D.L. Matthews A. Norman T. Solberg A. Vlieks Electrical and Computer Engineering University of California Davis USA Department of Neurosurgery University of California Davis USA Stanford Linear Accelerator Center University of Stanford USA Department of Applied Science University of California Davis USA Lawrence Livermore National Laboratory University of California USA Radiation Oncology and Biomedical Physics University of California Los Angeles USA

The combination of a high repetition rate (1 kHz), high power (TW-class, 100 fs) Ti:sapphire laser and a high gradient (/spl cong/75 MeV/m), high brightness (/spl epsi//spl cong/ 3 /spl pi/-mm-mrad) photoinjector/electron accelerator (15-100 MeV, /spl cong/1 nC per pulse) is predicted to produce high intensity (/spl cong/10/sup 11/ photons/sec), monoenergetic (<10% BW) X-rays tunable from 10 to 100 keV. The small source size (a/spl cong/10 /spl mu/m) permits significant magnification (up to 8/spl times/) to be employed in imaging applications.

关键词： X-ray scattering Cancer X-ray lasers Electromagnetic scattering Particle scattering Power lasers Brightness Electron accelerators Optical pulses X-ray imaging

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Modelling and Identification with Rational Orthogonal Basis Functions

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IFAC Proceedings Volumes 2000年第15期33卷 445-455页

作者： Paul Van den Hof Bo Wahlberg Peter Heuberger Brett Ninness Jozsef Bokor Tomás Oliveira e Silva Department of Applied Physics Delft University of Technology Lorentzweg 1 2628 CJ Delft The Netherlands S3 - Automatic Control Royal Institute of Technology S-100 44 Stockholm Sweden. Department of Electrical and Computer Engineering The University of Newcastle Callaghan NSW 2308 Australia. Computer and Automation Research Institute Hungarian Academy of Sciences Kende u. 13-17 H-1502 Budapest Hungary Dept. Electrónica e Telecommunicações University of Aveiro 3810-183 Aveiro Portugal

Decomposing dynamical systems in terms of orthogonal expansions enables the modelling/approximation of a system with a finite length expansion. By flexibly tuning the basis functions to underlying system characteristics, the rate of convergence of these expansions can be drastically increased, leading to highly accurate models (small bias) being represented by few parameters (small variance). Additionally algorithmic and numerical aspects are favourable. A recently developed general theory for basis construction will be presented, that is a generalization of the classical Laguerre theory. The basis functions are applied in problems of identification, approximation, realization, uncertainty modelling, and adaptive filtering, particularly exploiting the property that basis function models are linearly parametrized. Besides powerful algorithms, they also provide useful analysis tools for understanding the underlying identification/approximation algorithms.

关键词： System identification orthogonal basis functions series expansions model reduction parametrization

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DESIGN CONSIDERATIONS FOR A MULTI-MEGAWATT COAXIAL CAVITY GYROTRON AT 170 GHz.

DESIGN CONSIDERATIONS FOR A MULTI-MEGAWATT COAXIAL CAVITY GY...

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2000 25～(th) International Conference on Infrared and Millimeter Waves Conference Digest

作者： O.Dumbrajs Ch.T.Iatrou A.B.Pavelyev B.Piosczyk M.Thumm Department of Engineering Physics and Mathematics Helsinki University of Technology FIN-02150 Espoo Finland Department of Electrical and Computer Engineering National Technical University of Athens 15773 Zografou Athens Greece. Institute of Applied Physics Russian Academy of Sciences 46 Ulyanov Street 603600 Nizhny Novgorod Russia. Forschungszentrum Karlsruhe Institut für Hochleistungsimpuls-und Mikrowellentechnik Association EURATOM-FZK Hermann-von-Helmholtz-Platz 1 D-76344 Eggenstein-Leopoldshafen Germany Forschungszentrum Karlsruhe Institut für Hochleistungsimpuls-und Mikrowellentechnik Association EURATOM-FZK Hermann-von-Helmholtz-Platz 1 D-76344 Eggenstein-Leopoldshafen Germany

Some design considerations related to wall losses and mode competition in an ITER relevant coaxial cav-ity gyrotron are *** possibilities of heat redistribution and of reduction of mode competition bymeans of an inser... 详细信息

关键词： DESIGN CONSIDERATIONS FOR A MULTI-MEGAWATT COAXIAL CAVITY GYROTRON AT 170 GHz

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Effective Localization of Quantum Well Excitons in InGaN Quantum Well Structures with High InN Mole Fraction

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physica status solidi (a) 2000年第1期180卷

作者： S.F. Chichibu A. Setoguchi T. Azuhata J. Müllhäuser M. Sugiyama T. Mizutani T. Deguchi H. Nakanishi T. Sota O. Brandt K.H. Ploog T. Mukai S. Nakamura Institute of Applied Physics University of Tsukuba 1-1-1 Tennodai Tsukuba Ibaraki 305-8573 Japan Department of Materials Science and Technology Hirosaki University 3 Bunkyo-cho Aomori 036-8561 Japan Paul-Drude-Institut für Festkörperelektronik Hausvogteiplatz 5–7 D-10117 Berlin Germany Department of Electrical Electronics and Computer Engineering Waseda University 3-4-1 Ohkubo Shinjuku Tokyo 169-8555 Japan Department of Electrical Engineering Science University of Tokyo 2641 Yamazaki Noda Chiba 278-8510 Japan Department of Research and Development Nichia Chemical Industries Ltd. 491 Oka Kaminaka Anan Tokushima 774-8601 Japan

In x Ga 1– x N quantum well (QW) structures having high InN mole fractions, x , of both hexagonal and cubic phases were investigated to verify the importance of localized QW excitons in their spontaneous emission mechanisms. The internal piezoelectric field ( F PZ ) across the QWs in the hexagonal phase naturally increases with increasing x since the in-plain strain increases. The field was confirmed to point from the surface to the substrate. Absorption spectra of both hexagonal and cubic InGaN QWs exhibited a broad band-tail regardless of the presence of F PZ normal to the QW plane. The emission lifetime of the InGaN single-quantum-well amber light emitting diode increased with increasing detection wavelength. Its electroluminescence (EL) did not show a remarkable energy shift between 20 and 300 K, and the higher energy portion of the spectra increased more rapidly than that of the lower energy one. This may reflect thermal distribution of the Fermi level within the tail states. Since the well thickness is only 2.5 nm, the device exhibited a reasonably efficient emission in spite of the presence of F PZ and large number of threading dislocations.

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Finite-difference time-domain simulation of light scattering from multiple cells

Finite-difference time-domain simulation of light scattering...

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Quantum Electronics and Laser Science Conference, QELS 1999

作者： Myakov, A.V. Sergeev, A.M. Dolin, L.S. Myakov, A.V. Richards-Kortum, R. Institute of Applied Physics Russian Academy of Sciences 46 Uljanov st Nizhny Novgorod603600 Russia Biomedical Engineering program Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78731 United States

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