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Wildfire effects on permafrost and soil moisture in spruce forests of Interior Alaska

Journal of Forestry Research 2020年第2期31卷 553-563页

作者： Christopher Potter charles Hugny NASA Ames Research Center Moffett FieldCA 94035USA Interior Alaska Wilderness Consultants NenanaAKUSA

In the summer of 2015,hundreds of forest fires burned across the state of *** uncontrolled wildfires near the town of Tanana on the Yukon River were responsible for the largest portion of the area burned *** July 2017,field measurements were carried out in both unburned and burned forested areas nearly adjacent to one another,all within 15 miles of the village of *** surveys were used to first visually verify locations of different burn severity classes,(low,moderate,or high),estimated in 2016 from Landsat images(collected before and after the 2015 Tanana-area wildfires).Surface and soil profile measurements to 30-cm depth at these same locations were collected for evidence of moss layer and forest biomass *** temperature and moisture content were measured to 30-cm depth,and depth to permafrost was estimated by excavation wherever *** thermal infra-red images of the soil profiles were taken at each site location,and root-zone organic layer samples were extracted for further chemical *** supported the hypothesis that the loss of surface organic layers is a major factor determining post-fire soil water and temperature changes and the depth of permafrost *** the most severely burned forest sites,complete consumption of the living moss organic layer was strongly associated with both warming at the surface layer and increases in soil water content,relative to unburned forest *** temperatures at both 10-cm and 30-cm depths at burned forest sites were higher by 8-10C compared to unburned *** 15 cm,temperatures of unburned sites dropped gradually to frozen levels by 30 cm,while soil temperatures at burned sites remained above 5C to 30-cm *** water content measured at 3 cm at burned sites was commonly in excess of 30%by volume,compared to unburned *** strong correlation between burn index values and depth to permafrost measured across all sites sampled in July 2017 showed tha

关键词： Alaska Landsat Permafrost RdNBR Soil temperature Soil water Wildfire

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Homological behavior of idempotent subalgebras and Ext algebras

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Science China Mathematics 2020年第2期63卷 309-320页

作者： Colin Ingalls charles Paquette School of Mathematics and Statistics Carleton UniversityOttawaON K1S 5E6Canada Department of Mathematics and Computer Science Royal Military College of CanadaKingstonON K7K 7B4Canada

Let A be a(left and right) Noetherian ring that is semiperfect. Let e be an idempotent of A and consider the ring Γ :=(1-e)A(1-e) and the semi-simple right A-module Se := e A/e rad A. In this paper, we investigate the relationship between the global dimensions of A and Γ, by using the homological properties of Se. More precisely, we consider the Yoneda ring Y(e) := Ext_A~*(Se, Se) of e. We prove that if Y(e) is Artinian of finite global dimension, then A has finite global dimension if and only if so does Γ. We also investigate the situation where both A and Γ have finite global dimension. When A is Koszul and finite dimensional, this implies that Y(e) has finite global dimension. We end the paper with a reduction technique to compute the Cartan determinant of Artin algebras. We prove that if Y(e) has finite global dimension, then the Cartan determinants of A and Γ coincide. This provides a new way to approach the long-standing Cartan determinant conjecture.

关键词： global dimension Noetherian ring semiperfect ring idempotent subalgebra Cartan determinant

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Review on signal-by-wire and power-by-wire actuation for more electric aircraft

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Chinese Journal of Aeronautics 2017年第3期30卷 857-870页

作者： Jean-charles MAR Jian FU Institut National des Sciences Appliquees Institut Clement Ader (CNRS UMR 5312) Toulouse 31077 France School of Mechanical Engineering and Automation Beihang University Beijing 100083 China

The huge and rapid progress in electric drives offers new opportunities to improve the performances of aircraft at all levels：fuel burn,environmental footprint,safety,integration and production,serviceability,and *** for safety-critical applications like flight-controls,landing gears,and even engines is one of the major consumers of non-propulsive *** actuation with centralized hydraulic power generation and distribution and control of power by throttling has been well established for decades,but offers a limited potential of *** this context,electric drives become more and more attractive to remove the natural drawbacks of conventional actuation and to offer new opportunities for improving *** paper takes the stock,at both the signal and power levels,of the evolution of actuation for safety-critical applications in *** focuses on the recent advances and the remaining challenges to be taken toward full electrical actuation for commercial and military aircraft,helicopters,and *** logically starts by emphasizing the specificity of safety-critical actuation for *** following section addresses in details the evolution of aerospace actuation from mechanically-signaled and hydraulically-supplied to all electric,with special emphasis on research and development programs and on solutions entered into ***,the last section reviews the challenges to be taken to generalize the use of all-electric actuators for future aircraft programs.

关键词： Actuator Aerospace Electrohydrostatic Electromechanical Hydraulic More electric aircraft Power-by-wire Signal-by-wire

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Contribution of different granulometric populations to powder reactivity

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Particuology 2009年第1期7卷 39-44页

作者： Jean-charles Benezet Ali Benhassaine Ecole des Mines d’Alès 6 Avenue de Clavieres 30319 ALES CedexFrance Ecole des Mines d’Alès 6 Avenue de Clavieres 30319 ALES CedexFrance

In this article, different population contributions of quartz powders to chemical reactivity in pozzolanic reaction were studied. Deconvolution software was used to show the different particle populations of each product. Reaction of quartz powder with lime in the pozzolanic reaction at 20 ℃ shows that reactivity of each powder population depends on its particle size. Adsorbed fine particles on coarse particle surfaces have a significant role in the first term of the reaction. In a second term, the micropowders react. The mesopowders react only in the last reaction terms. Until now, the reactivity of adsorbed powder has been attributed to amorphization of the particle surface.

关键词： Quartz population Reaction rate Curve deconvolution Powder granulometry Specific surface area

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The roles of black phosphorus in performance enhancement of halide perovskite solar cells

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Journal of Energy Chemistry 2022年第4期31卷 672-683页

作者： Damir Aidarkhanov charles Surya Annie Ng Department of Electrical and Computer Engineering School of Engineering and Digital SciencesNazarbayev UniversityKabanbay Batyr Ave.53Nur-Sultan 010000Kazakhstan Innovation and Technology Commission Central Government Offices2 Tin Mei AvenueHong Kong 999077China

Hybrid organic-inorganic perovskite solar cells(PSCs) are considered to be the most promising thirdgeneration photovoltaic(PV) technology with the most rapid rate of increase in the power conversion efficiency(PCE). To date, their PCE values are comparable to the established photovoltaic technologies such as crystalline silicon. Intensive research activities associated with PSCs have been being performed,since 2009, aiming to further boost the device performance in terms of efficiency and stability via different strategies in order to accelerate the progress of commercialization. The emerging 2 D black phosphorus(BP) is a novel class of semiconducting material owing to its unique characteristics, allowing them to become attractive materials for applications in a variety of optical and electronic devices, which have been comprehensively reviewed in the literature. However, comprehensive reviews focusing on the application of BP in PSCs are scarce in the community. This review discusses the research works with the incorporation of BP as a functional material in PSCs. The methodology as well as the effects of employing BP in different regions of PSCs are summarized. Further challenges and potential research directions are also highlighted.

关键词： Perovskite solar cells Black phosphorus Power conversion efficiency Stability Low dimensional materials

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Could contact lens dryness discomfort symptoms sometimes have a neuropathic basis?

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Eye and Vision 2021年第1期8卷 101-108页

作者： charles W.McMonnies School of Optometry and Vision Science Faculty of Medicine and HealthUniversity of New South Wales77Cliff AvenueNorthbridge Sydney 2063Australia

Symptoms of dryness discomfort in soft contact lens wearers frequently lead to discontinuation from *** negative influence of pre-fitting tear dysfunctions appears likely to be exacerbated by the challenges to tear homeostasis caused by contact *** corneal mechanisms for symptoms in contact lens wearers are different to those for dry eye disease because the cornea is insulated by the lens from ambient conditions as well as from lid wiper friction during *** of dryness discomfort might be the consequence of increased lid wiper friction during blinking when the lens front surface becomes soiled and dry and exhibits very rapid tear break *** is possible that some cases of contact lens intolerance and discontinuation could be a function of lid wiper *** relation to the possibility of corneal neuropathy,a stagnant post-lens tear pool with the possibility of increased concentrations of metabolic by-products,cellular debris,and bacterial exotoxins,might have the potential to disturb the corneal epithelial and sub-basal *** by contact lens-induced inflammation to any neuropathic changes may partly depend on the degree to which inflammatory mediators are concentrated in a stagnant post-lens tear *** does not appear to be known if corneal neuropathic changes could develop under these *** chances of neuropathic involvement may be greater if discomfort develops after a significant period of successful wear and there is a history of comorbid pain *** and in vivo confocal microscopy in discontinued contact lens wearers may support a diagnosis of contact lens-related corneal neuralgia.

关键词： Contact lens Symptoms Neuropathy Sub-basal nerve plexus

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Apatite fission track and (U-Th)/He thermochronology from the Archean Tanzania Craton: Contributions to cooling histories of Tanzanian basement rocks

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Geoscience Frontiers 2017年第5期8卷 999-1007页

作者： charles H. Kasanzu Department of Geology University of Dar es Salaam P.O.Box 35052 Dar es Salaam Tanzania

Borehole and surface samples from the Archean Tanzania Craton were analysed for apatite fission track(AFT) and(U-Th)/He data with the aim of deciphering cooling histories of the basement rocks. Fission track dates from borehole and outcrop samples are Carboniferous-Permian(345± 33.3 Ma to271±31.7 Ma) whereas(U-Th)/He dates are Carboniferous-Triassic(336±45.8 Ma to 213±29 Ma) for outcrop grains and are consistently younger than corresponding AFT dates. Single grain(U-Th)/He dates from the borehole are likely to be flawed by excessive helium implantation due to their very low effective uranium contents, radiation damage and grain sizes. All AFT and(U-Th)/He dates are significantly younger than the stratigraphic ages of their host rocks, implying that the samples have experienced Phanerozoic elevated paleo-temperatures. Considerations of the data indicate removal of up to 9 km overburden since the *** modelling reveals a protracted rapid cooling event commencing during the early Carboniferous(ca. 350 Ma) at rates of 46 m/Ma ending in the Triassic(ca. 220 Ma). The model also suggests minor cooling during the Cretaceous of the samples to surface temperatures. The suggested later cooling event remains to be tested. The major cooling phase during the Carboniferous is interpreted to be associated with compressional tectonics during the Variscan Orogeny sensu far field induced stresses. Coeval sedimentation in the Karoo basins in the region suggests that most of the cooling of cratonic rocks during the Carboniferous was associated with denudation.

关键词： Thermochronology Exhumation Tanzania Craton

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Application of a water quality model for determining instream aeration station location and operational rules:A case study

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Water Science and Engineering 2018年第1期11卷 8-16页

作者： charles S.Melching Melching Water Solutions LLC GreenfieldWI 53221USA

Instream aeration has been used as a supplement to secondary treatment or a substitute for tertiary treatment for meeting dissolved oxygen （DO） standards in rivers. Many studies have used water quality models to determine the number, location, and capacity of instream aeration stations （IASs） needed to meet DO standards in combination with other pollution control measures. DO concentrations have been improved in the North Shore Channel and North Branch Chicago River by the Devon Avenue IAS for more than 35 years. A study was initiated to determine whether it was better to rehabilitate or relocate this station and to determine appropriate operational guidance for the IAS at the selected location. A water quality model capable of simulating DO concentrations during unsteady flow was used to evaluate the proper location for an IAS and operational guidance for this IAS. Three test years, a dry year, a wet year, and an extreme year, were considered in the evaluation. The study found that the Devon Avenue IAS should be rehabilitated as this location performed as well as or better than any of 10 alternative locations. According to the new operational guidance for this IAS, the amount of time with blowers operating could be substantially reduced compared to traditional operations while at the same time the attainment of the DO standards could be increased. This study shows that a carefully designed modeling study is key to effective selection, location, and operation of IASs such that attainment of DO standards can be maximized while operation hours of blowers can be minimized.

关键词： Instream aeration Dissolved oxygen Water quality modeling Water quality management Computer simulation

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One hundred years of population ecology:Successes,failures and the road ahead

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Integrative Zoology 2015年第3期10卷 233-240页

作者： charles J.KREBS Department of Zoology University of British ColumbiaVancouverCanada and Institute for Applied EcologyUniversity of CanberraCanberraAustralia

Population ecology is the most mature of the three subdisciplines of ecology partly because it has a solid mathematical foundation and partly because it can address the primary questions of distribution and abundance with experimental *** there is much left to do to integrate our population knowledge into community and ecosystem ecology to help address the global issues of food security and the conservation of *** different approaches are now being developed to bring about this integration and much more research will be necessary to decide which if any will be most useful in achieving our goals of explaining the changes we see in the distribution and abundance of animals and *** web ecology would appear to be the best approach at present because it uses the detailed information of the population ecology of particular species in combination with data on consumer-resource interactions to apply to the applied problems of biodiversity conservation,food security,pest management and disease *** we can use our understanding of population ecology to address the practical problems of our time in a creative way,we will benefit both the human population and the Earth’s *** remains to be done.

关键词： abundance geographic distributions history of ecology population models

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Updates on esophageal and gastric cancers

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World Journal of Gastroenterology 2006年第20期12卷 3237-3242页

作者： Amy Gallo charles Cha Resident Department of Surgery Yale University School of Medicine333 Cedar St.FMB 121New HavenCT 06520United States Department of Surgery Yale University of School of Medicine 333 Cedar St.FMB 121New HavenCT 06520United States

Esophageal and gastric cancers are both common and deadly. Patients present most often after disease progression and survival is therefore poor. Due to demographic variability and recent changes in disease incidence, much emphasis has been placed on studying risk factors for both esophageal and gastric cancers. However, with increasing understanding of these diseases, low survival rates persist and continued intensive studies are necessary to optimize treatment plans. This review article discusses updates in the evolving epidemiology, clinical presentation, risk factors, and diagnostic and treatment modalities of esophageal and gastric cancers.

关键词： Gastric cancer Esophageal cancer Surgery Treatment

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