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Alternative expressions for stand diameter in complex forests

Forest Ecosystems 2023年第3期10卷 328-336页

作者： mark j.Ducey john A.Kershaw jr. Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA Faculty of Forestry and Environmental Management University of New BrunswickFrederictonNBCanada

Quadratic mean diameter is the most frequently reported descriptor of the diameter distribution of *** such,it is often used as an indicator of forest stand structure,developmental stage,and ecological and economic ***,quadratic mean diameter can be heavily influenced by the presence or absence of large numbers of small stems in lower canopy strata,and it is also sensitive to left-truncation of the diameter distribution,making its interpretation across inventories with different protocols ***,we examine three alternative expressions of stand diameter:the arithmetic and quadratic mean diameter of the thickest 100 trees per hectare,and the basal area-weighted mean *** data from the United States Forest Inventory and Analysis program for New York and New England,these alternative expressions showed closer correlation with multiple stand structural variables than did quadratic mean diameter,including merchantable cubic and board foot volume per hectare,aboveground live tree carbon per hectare,and total number of live and dead standing trees greater than 40 cm diameter at breast height per hectare(previously proposed as an index of old-growth structure).Arithmetic and quadratic mean diameter of the thickest 100 trees per hectare showed nearly identical performance,and the strongest correlations across the *** develop closed-form expressions for these variables when the diameter distribution is a Weibull,and illustrate their behavior relative to quadratic mean diameter for that *** the reasons for prevalence of quadratic mean diameter as an indicator remain valid,we suggest that these alternative measures should be more widely reported and analyzed to give a more informative depiction of stand structure and development in complex forests.

关键词： Forest structure Diameter at breast height Weibull distribution

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Boosting energy-storage capability in carbon-based supercapacitors using low-temperature water-in-salt electrolytes

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journal of Energy Chemistry 2022年第7期31卷 521-530,I0013页

作者： joao Pedro A.Santos Manuel j.Pinzón érick A.Santos Rafael Vicentini Cesar j.B.Pagan Leonardo M.Da Silva hudson Zanin Brazilian Renewable Energies Center for Innovation on New EnergiesSchool of Electrical and Computer EngineeringUniversity of CampinasSao Paulo 13083-852Brazil Department of Semiconductors Instruments and PhotonicsSchool of Electrical and Computer EngineeringUniversity of CampinasSao Paulo 13083-852Brazil Laboratory of Fundamental and Applied Electrochemistry Department of ChemistryFederal University of Jequitinhonha e Mucuri’s ValleyMinas Gerais 39100-000Brazil

Supercapacitors(SCs) are high-power energy storage devices with ultra-fast charge/discharge *** using concentrated aqueous-based electrolytes can work at low temperatures due to their intrinsic properties, such as higher freezing point depression(FPD) and robustness. Besides the traditional organic-and aqueous-based(salt-in-water) electrolytes used in SCs, water-in-salt(WISE) sodium perchlorate electrolytes offer high FPD, non-flammability, and low-toxicity conditions, allowing the fabrication of safer, environmentally friendly, and more robust devices. For the first time, this work reports a comprehensive study regarding WISE system’s charge-storage capabilities and physicochemical properties under low-temperature conditions(T < 0 ℃) using mesoporous carbon-based electrodes. The effect of temperature reduction on the electrolyte viscosity and electrical properties was investigated using different techniques and the in-situ(or operando) Raman spectroscopy under dynamic polarization *** cell voltage, equivalent series resistance, and specific capacitance were investigated as a function of the temperature. The cell voltage(U) increased ~ 50%, while the specific capacitance decreased ~20%when the temperature was reduced from 25 ℃ to -10 ℃. As a result, the maximum specific energy(E = CU^(2)/2) increased ~ 100%. Therefore, low-temperature WISEs are promising candidates to improve the energy-storage characteristics in SCs.

关键词： Carbon supercapacitors Water-in-salt electrolytes Low-temperature charge-storage Specific energy improvement at low temperatures

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Are sperm capacitation and apoptosis the opposite ends of a continuum driven by oxidative stress？

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Asian journal of Andrology 2015年第4期17卷 633-639页

作者： Robert j Aitken mark A Baker Brett Nixon Priority Research Centre in Reproductive Science Discipline of Biological Sciences and Hunter Medical Research Institute University of Newcastle NSW 2308 Australia.

This chapter explores the possibility that capacitation and apoptosis are linked processes joined by their common dependence on the continued generation of reactive oxygen species （ROS）. According to this model capacitation is initiated in spematozoa following their release into the female reproductive tract as a consequence of intracellular ROS generation, which stimulates intracellular cAMP generation, inhibits tyrosine phosphatase activity and enhances the formation of oxysterols prior to their removal from the sperm surface by albumin. The continued generation of ROS by capacitating populations of spermatozoa eventually overwhelms the limited capacity of these cells to protect themselves from oxidative stress. As a result the over-capacitation of spermatozoa leads to a state of senescence and the activation of a truncated intrinsic apoptotic cascade characterized by enhanced mitochondrial RO$ generation, lipid peroxidation, motility loss, caspase activation and phosphatidylserine externalization. The latter may be particularly important in instructing phagocytic leukocytes that the removal of senescent, moribund spermatozoa should be a silent process unaccompanied by the generation of proinflammatory cytokines. These observations reveal the central role played by redox chemistry in defining the life and death of spermatozoa. A knowledge of these mechanisms may help us to engineer novel solutions to both support and preserve the functionality of these highly specialized cells.

关键词： apoptosis reactive oxygen species sperm capacitation

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Robust Adaptive Model Tracking for Distributed Parameter Control of Linear Infinite-dimensional Systems in Hilbert Space

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IEEE/CAA journal of Automatica Sinica 2014年第3期1卷 294-301页

作者： mark j.Balas Susan A.Frost the Embry-Riddle Aeronautical University the NASA Ames Research Center

This paper is focused on adaptively controlling a linear infinite-dimensional system to track a finite-dimensional reference *** a linear continuous-time infinite-dimensional plant on a Hilbert space with disturbances of known waveform but unknown amplitude and phase,we show that there exists a stabilizing direct model reference adaptive control law with the properties of certain disturbance rejection and *** plant is described by a closed,densely defined linear operator that generates a continuous semigroup of bounded operators on the Hilbert space of *** central result will show that all errors will converge to a prescribed neighborhood of zero in an infinitedimensional Hilbert *** result will not require the use of the standard Barbalat’s lemma which requires certain signals to be uniformly *** result is used to determine conditions under which a linear infinite-dimensional system can be directly adaptively controlled to follow a reference *** particular,we examine conditions for a set of ideal trajectories to exist for the tracking *** results are applied to adaptive control of general linear diffusion systems described by self-adjoint operators with compact resolvent.

关键词： Adaptation models Adaptive control Hilbert space Learning (artificial intelligence) Robustness Trajectory adaptive control algorithm adaptive theory distributed parameter system Distributed parameter systems Hilbert space trajectory Adaptation models reference model adaptive control Robustness Computer algorithms

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Protecting miners from coal bursts during development above historic mine workings in Harlan County,KY

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International journal of Mining Science and Technology 2021年第1期31卷 111-116页

作者： Christopher mark Mine Safety and Health Administration PittsburghPA 15236USA

In order to reach a large,untapped reserve of high-quality coal,D8 Cloverlick Mine proposed to mine a corridor nearly 600 m deep beneath the Benham Spur of Black Mountain,Kentucky’s highest peak.D8 Cloverlick Mine was extracting the Owl seam,but the corridor’s route lay approximately 20 m above century-old mine workings in the C–(Darby)*** to the concern,three serious coal bursts had recently occurred in nearby Owl seam *** of the old workings seemed to indicate that the underlying C–seam had been fully ***,two of the coal bursts had occurred above areas where the C–Seam was also shown as mined *** Safety and Health Administration(MSHA)Technical Support therefore investigated the records of past mining to better understand the old mine *** conditions observed in current Owl seam workings were also compared with the maps of the old C–seam *** study concluded that the presence of hazardous underlying remnants could not be ruled *** mitigate the burst risk,D8 Cloverlick Mine adopted a strategy of stress probe drilling.A self-propelled coal drill was used to auger 11.5-m-long,small diameter holes in advance of *** each hole was drilled,the cuttings were measured to detect the presence of highly stressed *** the crossing was successfully completed without incident.

关键词： Coal bursts Underground mining Room-and-pillar Destressing

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Performance analysis and design of loitering munitions: A comprehensive technical survey of recent developments

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Defence Technology（防务技术） 2022年第3期18卷 325-343页

作者： mark Voskuijl Faculty of Military Sciences Netherlands DefenceAcademyDenHelderThe Netherlands

Loitering munitions are increasingly used in armed *** extensive database of loitering munitions is developed based on information available in the public *** database includes dimensions,weights,and performance parameters such as flight endurance and communication *** upon this dataset,6 categories of loitering munitions are identified and statistical trends in the form of equations are provided for each *** statistical trends are supported by aircraft performance theory tailored to loitering munitions ***,the combination of the database,statistical trends and aircraft performance theory can be used to analyse the flight performance and design considerations of new loitering munitions of which only limited non-technical information is available in the public domain such as pictures and news *** on the statistical trends and aircraft performance theory it is concluded that for long range applications,the preferred design solution is the conventional *** cruciform configuration is beneficial in case precision flight path control is of prime *** tandem wing configuration combines the benefits of a canister launch and relatively high aspect ratio wings suitable for long range ***,the delta wing design provides a large internal volume and a high terminal attack *** example case studies are included to illustrate the flight performance capabilities of two types of loitering munitions used in the current conflict in Yemen(a long range conventional design and a delta wing configuration).

关键词： Loitering munition Unmanned aerial vehicle Flight performance Design

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An updated empirical model for ground control in *** coal mines

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International journal of Mining Science and Technology 2021年第2期31卷 163-174页

作者： Christopher mark Mine Safety and Health Administration PittsburghPA 15217USA

Multiple seam interactions are a major source of ground instability in several *** methods are well suited for this problem,because while the mechanics multiple seam interactions are very complex and poorly understood,many mining case histories are available for *** study makes use of an updated database that includes 356 multiseam case histories,including 67 unsuccessful *** paper describes in detail the process used to design the study,collect the data,conduct the statistical analysis,and develop the quantitative *** model can be used for mine planning in multiple seam situations,and has been made available as a module within the Analysis of Coal Pillar Stability(ACPS)computer program.

关键词： Underground Coal Multiseam Ground control Pillar design Empirical

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Assessment of oxide nanoparticle stability in liquid phase transmission electron microscopy

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Nano Research 2019年第9期12卷 2355-2363页

作者： mark j. Meijerink Krijn P. de jong jovana Zecevic Inorganic Chemistry and Catalysis Debye Institute of Nanomaterials ScienceUtrecht UniversityUniversiteitsweg 993584 CG UtrechtThe Netherlands

Studying liquid phase nanoscale dynamic processes of oxide nanoparticles is of considerable interest to a wide variety of *** developed liquid phase transmission electron microscopy(LP-TEM)is a promising technique,but destabilization of oxides by solid-liquid?electron interactions remains an important *** this work we present a methodology to assess LP-TEM oxide stability in an aqueous phase,by subjecti ng several oxides of tech no logical importa nee to a controlled electr on dose in *** show a correlati on based on the Gibbs free en ergy of oxide hydrati on that can be used to assess the stability of oxides and dem on strate the existenee of several remarkably stable oxides,with no observable structural changes after one hour of electron beam irradiation in *** such destabilization phenomena combined with the identification of stable oxides allows for designing LP-TEM experiments free from adverse beam effects and thus in vestigati ons of numerous releva ntnano scale processes in water.

关键词： liquid phase transmission electron microscopy(LP-TEM) transmission electron microscopy electron beam damage metal oxide nano materials oxide stability

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Keratinized Nuptial Spines Are Used for Male Combat in the Emei Moustache Toad(Leptobrachium boringii)

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Asian Herpetological Research 2011年第3期2卷 142-148页

作者： Cameron M. hudson Xianjin HE jinzhong FU Department of Integrative Biology University of Guelph50 Stone Road East College of Life Science and Technology Southwest University for Nationalities

We describe the natural history and reproductive behaviour of the Emei Moustache Toad(Leptobrachium boringii) with an emphasis on the development of keratinized nuptial spines in males and document combat behaviour for the first time in this species. Between February and March of 2011, 19 female and 43 male L. boringii from Mount Emei UNESCO World Heritage Site, Sichuan, China were observed throughout the breeding season. This species exhibits male-biased sexual size dimorphism(SSD) with limited evidence of paternal care(nest guarding by males). Prior to the breeding season males grow 10 – 16 keratinized spines on their upper lip, which fall off once the season has ended. Throughout the breeding season males construct and defend aquatic nests where they produce advertisement calls to attract females. During this time we documented 14 cases involving a total of 22 males where males used their moustaches for aggressive interaction. Combat typically occurred at the beginning of the season when males would compete for a limited number of available nest sites. Neither male body size, nor body condition significantly affects the outcome of an aggressive interaction, suggesting that size may not be the only factor influencing an individual’s chance of victory. Our evidence for male competition and aggression, along with observed paternal care are potential mechanisms to explain the evolution of male-biased SSD observed in this species.

关键词： reproductive behaviour territoriality Leptobrachium boringii secondary sexual characters

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Three-dimensional steep wave impact on a vertical cylinder

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journal of Hydrodynamics 2016年第4期28卷 523-533页

作者： Ioannis K.CHATjIGEORGIOU Alexander A.KOROBKIN mark j.COOKER School of Mathematics University of East Anglia School of Naval Architecture and Marine Engineering National Technical University of Athens

In the present study we investigate the 3-D hydrodynamic slamming problem on a vertical cylinder due to the impact of a steep wave that is moving with a steady *** linear theory of the velocity potential is employed by assuming inviscid,incompressible fluid and irrotational *** the problem is set in 3-D space,the employment of the Wagner condition is *** set of equations we pose,is presented as a mixed boundary value problem for Laplace＇s equation in *** from the mixedtype of boundary conditions,the problem is complicated by considering that the region of wetted surface of the cylinder is a set whose boundary depends on the vertical coordinate on the cylinder up to the *** make some simple assumptions at the start but otherwise we proceed *** find closed-form relations for the hydrodynamic variables,namely the time dependent potential,the pressure impulse,the shape of the wave front（from the contact point to beyond the cylinder） and the slamming force.

关键词： cylinder hydrodynamic incompressible steep Wagner employment otherwise coordinate analytically assumptions

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