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Corotating drift-bounce resonance of plasmaspheric electron with poloidal ULF waves

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Earth and Planetary Physics 2017年第1期1卷 2-12页

作者： Qiu-Gang Zong YongFu Wang Jie Ren XuZhi Zhou SuiYan Fu Robert Rankin Hui Zhang Institute of Space Physics and Applied Technology Peking University Department of Physics University of Alberta Physics Department and Geophysical Institute University of Alaska Fairbanks

The purpose of this paper is to understand how low energy plasmaspheric electrons respond to ULF waves excited by interplanetary shocks impinging on magnetosphere. It is found that both energy and pitch angle dispersed plasmaspheric electrons with energy of a few eV to tens of eV can be generated simultaneously by the interplanetary shock. The subsequent period of successive dispersion signatures is around 40 s and is consistent with the ULF wave period(third harmonic). By tracing back the energy and pitch angle dispersion signatures, the position of the electron injection region is found to be off-equator at around -32° in the southern hemisphere. This can be explained as the result of injected electrons being accelerated by higher harmonic ULF waves(e.g. third harmonic) which carry a larger amplitude electric field off-equator. The dispersion signatures are due to the flux modulations(or accelerations) of " local" plasmaspheric electrons rather than electrons from the ionosphere. With the observed wave-borne large electric field excited by the interplanetary shock impact, the kinetic energy can increase to a maximum of 23 percent in one bouncing cycle for plasmaspheric electrons satisfying the drift-bounce resonance condition by taking account of both the corotating drift and bounce motion of the local plasmaspheric electron.

关键词： drift-bounce resonance plasmaspheric electron poloidal mode ULF wave

3D porous PTFE membrane filled with PEO-based electrolyte for all solid-state lithium-sulfur batteries

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Rare Metals 2022年第8期41卷 2834-2843页

作者： Zhen-Chao Li Teng-Yu Li Yi-Rui Deng Wen-Hao Tang Xiao-Dong Wang Jin-Lin Yang Qiang Liu Lei Zhang Qiang Wang Rui-Ping Liu Department of Materials Science and Engineering China University of Mining&Technology(Beijing)Beijing100083China School of Materials Science and Engineering Tsinghua UniversityBeijing100083China Department of Mechanical Engineering University of Alaska FairbanksPO Box 755905FairbanksAK99775USA Chongqing Key Laboratory of Green Aviation Energy and Power Chongqing Jiaotong UniversityChongqing401135China

Owing to the low cost and high theoretical energy density,lithium-sulfur battery has become one of the most promising energy storage battery ***,the inherent cycle instability and safety problems of traditional liquid lithium-sulfur batteries greatly limit their commercial *** this work,polytetrafluoroethylene(PTFE)membrane was introduced into Li_(7)La_(3)Zr_(2)O_(12)(LLZO)@poly(ethylene oxide)(PEO)-based composite electrolyte as a supporting framework to prepare a new PTFE@LLZO@PEO composite electrolyte for lithium-sulfur *** introduction of PTFE membrane further improved the mechanical properties and thermal stability of the *** ionic conductivity of the prepared PTFE@LLZO@PEO solid electrolyte was5.03×10^(-5)S·cm^(-1)at 30℃and 2.54×10^(-4)S·cm^(-1)at60℃.Moreover,the symmetric battery exhibited high cycle stability(300 h).The Li-S battery based on PTFE@LLZO@PEO electrolyte exhibited excellent electrochemical performance.

关键词： Lithium-sulfur battery All solid-state battery Composite electrolyte Shuttle effect Lithium dendrite

Bed Forms and Sediment Characteristics along the Thalweg on the Tanana River near Nenana, alaska, USA

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Natural Resources 2013年第1期4卷 20-30页

作者： Horacio Toniolo Civil and Environmental Engineering Department University of Alaska Fairbanks Fairbanks USA

Sediment sampling and longitudinal river-bottom surveys were conducted along the thalweg on the Tanana River near the city of Nenana, alaska, USA, to provide basic information for the engineering design requirements of hydrokinetic devices to be deployed in the area. The study reach was located at approximately 64°33'50'N and 149°04'W. The Tanana is a large glacier-fed river, with open-water flow conditions from May to October. The river presents a single channel in the study area. Granulometric analyses of sediment moving near the riverbed reveals the coexistence of three distinctive types of sediment along the study reach: 1) nearly uniform fine sand;2) bimodal distributions containing fine sand and medium gravel;and 3) medium gravel. Preliminary relationships between sediment loads and discharge were developed. Dunes with small superimposed dunes were found along the reach. The basic geometric parameters (i.e., wavelength and height) of dunes were measured, and steepness was calculated. In general, dune wavelength increased with increasing discharge. Dune wavelengths ranged from 41 to 67 m, while small-dune wavelengths ranged from 13 to 16 m. Steepness increased slightly with increasing discharge.

关键词： Sand-Gravel Riverbeds Dunes Steepness Thalweg Suspended-Sediment Load Bed Load

Hydraulic Characteristics and Suspended Sediment Loads during Spring Breakup in Several Streams Located on the National Petroleum Reserve in alaska, USA

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Natural Resources 2013年第2期4卷 220-228页

作者： Horacio Toniolo Dragos Vas Peter Prokein Richard Kenmitz Erica Lamb Dave Brailey Brailey Hydrologic Consultants Anchorage USA Bureau of Land Management Arctic Field Office Fairbanks USA Civil and Environmental Engineering Department University of Alaska Fairbanks Fairbanks USA Institute of Northern Engineering University of Alaska Fairbanks Fairbanks USA Water and Environmental Research Center University of Alaska Fairbanks Fairbanks USA

This article presents results from a broad field campaign involving discharge and surface-water slope measurements, water sampling, and longitudinal river-bed profile surveys. During the spring breakup of 2011, fieldwork was carried out in several pristine streams located in the National Petroleum Reserve in alaska;the studied streams cover two main regions: 1) foothills (Ikpikpuk River, Seabee Creek, Prince Creek, and Otuk Creek);2) coastal plain (Fish Creek, Judy Creek, and Ublutuoch River). Reported data includes basic geometric and hydraulic characteristics such as channel width and depth, cross-sectional area, average velocity, friction factor, shear stress, suspended sediment concentrations from autosamplers and grab samples, and dune dimensions and steepness ratios. The measured discharge in different streams ranged from 2 to 853 m3/s, which corresponded to post-breakup and near peak conditions, respectively. The temporal variation of Manning’s n was in phase with measured discharge, with high values of n associated with the presence of floating ice during the measurements. Calculations indicate that sediment particle sizes ≤2 mmmoved during the measurements. In general, variations in discharge were accompanied by changes in suspended sediment concentrations.

关键词： Suspended Sediment Concentration Bedforms Resistance Coefficient Spring Breakup Arctic Hydrology

Indoor and Outdoor Particulate Matter Exposure of Rural Interior alaska Residents

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Open Journal of Air Pollution 2020年第3期9卷 37-60页

作者： Stanley G. Edwin Nicole Mölders Council of Athabascan Tribal Governments Fort Yukon USA university of alaska fairbanks College of Natural Science and Mathematics Fairbanks USA university of alaska fairbanks Geophysical Institute Fairbanks USA

To assess the exposure of residents in rural communities in the Yukon Flats to particulate matter of 2.5 μm or less in diameter (PM2.5), both indoor and outdoor concentration observations were carried out from March to September 2019 in Ft. Yukon, Alaska. Indoor concentrations were measured at 0.61 m (breathing level during sleeping) in homes and at 1.52 m heights (breathing level of standing adult) in homes and office/commercial buildings. Air quality was better at both heights in cabins than frame homes both during times with and without surface-based inversions. In frame houses, concentrations were higher at 0.61 m than 1.52 m, while the opposite is true typically for cabins. Differences between shoulder season and summer indoor concentrations in residences were related to changes in heating, subsistence lifestyle and mosquito repellents. In summer, office and commercial buildings, air quality decreased due to increased indoor emissions related to increased use of equipment and mosquito pics as well as more merchandise. During summer indoor concentrations reached unhealthy for sensitive groups to hazardous conditions for extended times that even exceeded the high outdoor concentrations. Due to nearby wildfires, July mean outdoor concentrations were 55.3 μg·m-3 which exceeds the 24-h US National Ambient Air Quality Standard of 35 μg·m-3. Indoor and outdoor concentrations correlated the strongest with each other for office/commercial buildings, followed by frame houses and cabins. Office/commercial buildings with temperature monitors had one to two orders of magnitude lower concentrations than those without.

关键词： Indoor Air Quality Yukon Flats alaska Fine Particulate Matter PM2.5 Exposure in Rural alaska Tribal Air Quality Study

L-Band InSAR Penetration Depth Experiment, North Slope alaska

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Journal of Geoscience and Environment Protection 2017年第3期5卷 14-30页

作者： Reginald R. Muskett Geophysical Institute University of Alaska Fairbanks USA

Since the first spacecraft-based synthetic aperture radar (SAR) mission NASA’s SEASAT in 1978 radars have been flown in Low Earth Orbit (LEO) by other national space agencies including the Canadian Space Agency, European Space Agency, India Space Research Organization and the Japanese Aerospace Exploration Agency. Improvements in electronics, miniaturization and production have allowed for the deployment of SAR systems on aircraft for usage in agriculture, hazards assessment, land-use management and planning, meteorology, oceanography and surveillance. LEO SAR systems still provide a range of needful and timely information on large and small-scale weather conditions like those found across the Arctic where ground-base weather radars currently provide limited coverage. For investigators of solid-earth deformation attention must be given to the atmosphere on Interferometric SAR (InSAR) by aircraft and spacecraft multi-pass operations. Because radar has the capability to penetrate earth materials at frequencies from the P- to X-band attention must be given to the frequency dependent penetration depth and volume scattering. This is the focus of our new research project: to test the penetration depth of L-band SAR/InSAR by aircraft and spacecraft systems at a test site in Arctic alaska using multi-frequency analysis and progressive burial of radar mesh-reflectors at measured depths below tundra while monitoring environmental conditions. Knowledge of the L-band penetration depth on lowland Arctic tundra is necessary to constrain analysis of carbon mass balance and hazardous conditions arising from permafrost degradation and thaw, surface heave and subsidence and thermokarst formation at local and regional scales.

关键词： alaska Tundra SAR/InSAR Aircraft Spacecraft

US-China Relations:Nationalism,the Trade War,and COVID-19

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Fudan Journal of the Humanities and Social Sciences 2021年第1期14卷 23-40页

作者： Brandon M.Boylan Jerry McBeath Bo Wang university of alaska fairbanks(UAF) 603 C/D Gruening Building1747 South Chandalar DriveFairbanksAK 99775USA Emeritus of Political Science University of Alaska Fairbanks(UAF)1777 Red Fox DriveFairbanksAK 99709USA School of International Relations China University of International Business and Economics(UIBE)Mail Box 100No.10 Huixin East StreetChangyang DistrictBeijing 100029People’s Republic of China

The trade war between the USA and China has shocked many across the world.A disruption to the interdependence of the two largest economies seemed ***,in an effort to thwart China’s economic practices and boost the US economy,President Trump’s administration levied tariffs on Chinese imports shortly after taking office,moving US foreign economic policy from liberalism,practiced for decades,to *** has retaliated,and the trade war continues *** conceptual insights from the nationalism literature,we explore the nationalist roots of the trade war from both the US and Chinese *** the USA,the Trump administration’s plan to achieve energy autonomy,decrease reliance on foreign resources,and reinvigorate the manufacturing sector has led to protectionist policies,the othering of China,and hence the trade *** reluctant to enter the conflict,China has rebuffed the USA,resisting and counterattacking US actions,owing to a long-felt sense of persecution in the global space and an eagerness to participate fully,and lead in some issue areas,in international *** conflict continues into the COVID-19 era,marked by US scapegoating of China and hits to economic *** both sides are convinced they have achieved their goals,or the USA undergoes an administration change,the conflict will likely continue.

关键词： US-China relations Nationalism International trade Natural resources Energy Political economy COVID-19

Particulate Matter Exposure of Rural Interior Communities as Observed by the First Tribal Air Quality Network in the Yukon Flat

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Journal of Environmental Protection 2018年第13期9卷 1425-1448页

作者： Stanley G.Edwin Nicole Molders Council of Athabascan Tribal Governments Fort YukonUSA College of Natural Science and Mathematics University of Alaska FairbanksFairbanksUSA Geophysical Institute University of Alaska FairbanksFairbanksUSA

A tribal-owned network of aerosol monitors and meteorological stations was installed at Ts’aahudaaneekk’onh Denh (Beaver), Gwichyaa Zheh (Fort Yukon), Jalgiitsik (Chalkyitsik), and Danzhit Khànlaii (Circle) in the Yukon Flats, alaska. Surface inversions occurred under calm wind conditions due to radiative cooling. In May, local emissions governed air quality with worst conditions related to road and river dust. As the warm season progressed, worst air quality was due to transport of pollutants from upwind wildfires. During situations without smoke or when smoke existed at layers above the surface inversion, concentrations of particulate matter of less than 2.5 micrometer in diameter or less (PM2.5) were explainable by the local emissions;24-h means remained below 25 μg·m-3. Absorption of solar radiation in the smoke layer and upward scattering enhanced stability and fostered the persistence of the surface inversions. During smoke episodes without the presence of a surface inversion, daily mean concentrations exceeded 35 μg·m-3 often for several consecutive days, at all sites. Then concentrations temporally reached levels considered unhealthy.

关键词： Summer Surface Inversions in the Yukon Flats PM_(2.5) Concentrations in Rural alaska Villages First Tribal Air-Quality Network in the Yukon Flats

Towards superior lithium-sulfur batteries with metal-organic frameworks and their derivatives

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Tungsten 2022年第4期4卷 269-283页

作者： Ning Yuan Yi-Rui Deng Shan-Hu Wang Li Gao Jin-Lin Yang Na-Chuan Zou Bing-Xin Liu Jun-Qing Zhang Rui-Ping Liu Lei Zhang School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing100083China School of Mechanical Engineering Qinghai UniversityXining810016China School of Materials Science and Engineering Tsinghua UniversityBeijing100083China Department of Mechanical Engineering University of Alaska FairbanksFairbanksAK99775-5905USA

Lithium-sulfur batteries(LSBs)are one of the most promising energy storage devices in the future due to their high theoretical specific capacity(1675 mA·h·g^(-1))and energy density(2600 W·h·kg^(-1)).However,the severe capacity decay caused by the shuttle effect of polysulfides needs to be addressed before the practical ***-organic frameworks(MOFs)and their derivatives are known for their large specific surface area,high porosity,abundant functional groups,and good chemical ***,they have been widely investigated in *** review introduces the principles of the LSBs and origination of the shuttle effect first summarizes various methods of limiting polysulfide diffusion by MOFs and their derivatives both in cathodes and separators,and provides an in-depth discussion of the immobilization mechanisms,which helps to understand the advantages and disadvantages of each *** mechanisms,such as structure and pore size tuning,chemical absorption,and catalytic conversion,are ***,based on the method of MOFs and their derivatives to inhibit the diffusion of polysulfides,the application prospect of MOFs and their derivatives in LSBs technology are proposed.

关键词： Metal-organic frameworks Lithium-sulfur batteries Cathode Separator Shuttle effect