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Height-diameter models for King Boris fir(Abies borisii regis Mattf.) and Scots pine(pinus sylvestris L.) in Olympus and pieria Mountains, Greece

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Journal of Mountain Science 2024年第5期21卷 1475-1490页

作者： Dimitrios i.RApTiS Dimitra pApADOpOULOU Angeliki pSARRA Athanasios A.FALLiAS Aristides G.TSiTSANiS Vassiliki KAZANA Renewable Natural Resource Management and Bioeconomy Laboratory Department of Forest and Natural Environment SciencesInternational Hellenic University66100 DramaGreece

in forest science and practice, the total tree height is one of the basic morphometric attributes at the tree level and it has been closely linked with important stand attributes. in the current research, sixteen nonlinear functions for height prediction were tested in terms of their fitting ability against samples of Abies borisii regis and pinus sylvestris trees from mountainous forests in central Greece. The fitting procedure was based on generalized nonlinear weighted regression. At the final stage, a five-quantile nonlinear height-diameter model was developed for both species through a quantile regression approach, to estimate the entire conditional distribution of tree height, enabling the evaluation of the diameter impact at various quantiles and providing a comprehensive understanding of the proposed relationship across the distribution. The results clearly showed that employing the diameter as the sole independent variable, the 3-parameter Hossfeld function and the 2-parameter N?slund function managed to explain approximately 84.0% and 81.7% of the total height variance in the case of King Boris fir and Scots pine species, respectively. Furthermore, the models exhibited low levels of error in both cases(2.310m for the fir and 3.004m for the pine), yielding unbiased predictions for both fir(-0.002m) and pine(-0.004m). Notably, all the required assumptions for homogeneity and normality of the associated residuals were achieved through the weighting procedure, while the quantile regression approach provided additional insights into the height-diameter allometry of the specific species. The proposed models can turn into valuable tools for operational forest management planning, particularly for wood production and conservation of mountainous forest ecosystems.

关键词： Generalized nonlinear weighted regression Monte Carlo cross-validation Mountainous ecosystems Quantile regression Central Greece

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Ultrafast optical modulation of the fluorescence from a single-photon emitter in silicon carbide

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photonics Research 2024年第5期12卷 941-946页

作者： MeNGTiNG He YUJiNG CAO JUNJie LiN ZHipiNG JU BOTAO WU e WU State Key Laboratory of precision Spectroscopy East China Normal UniversityShanghai 200241China photon Technology(Zhejiang)Co. Ltd.Jiaxing 314100China National Key Laboratory of Materials for integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200000China Department of physics and Shanghai Key Laboratory for Magnetic Resonance East China Normal UniversityShanghai 200241China Chongqing Key Laboratory of precision Optics Chongqing Institute of East China Normal UniversityChongqing 401120China Collaborative innovation Center of extreme Optics Shanxi UniversityTaiyuan 030006China

The quest for the room-temperature optical transistor based on nonlinearities in single atoms or molecules is attracting a lot of *** this work,a single-photon emitter in cubic silicon carbide is verified that can operate as an optical switch at room temperature under pulsed green laser illumination with a near-infrared pulsed laser as the control *** demonstrated an ultrafast and reversible optical modulation with a high photoluminescence intensity suppression ratio up to 97.9%and a response time as short as 287.9±5.7 *** current development provides insights for high-precision and ultrafast optical switches,with possibilities for integration with emerging electronic installations to realize more intelligent photoelectric integrated devices.

关键词： emitter carbide photon

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Anthropogenic influence on Decadal Changes in Concurrent Hot and Dry events over China around the Mid-1990s

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Advances in Atmospheric Sciences 2024年第2期41卷 233-246页

作者： Qin SU Buwen DONG Fangxing TiAN Nicholas p.KLiNGAMAN Yunnan Key Laboratory of Meteorological Disasters and Climate Resources in the Great Mekong Subregion Yunnan UniversityKunming 650500China Department of Atmospheric Sciences Yunnan UniversityKunming 650500China National Centre for Atmospheric Science Department of MeteorologyUniversity of ReadingReadingRG66BBUK Geofysisk institut University of BergenBergen 5007Norway Citadel investment Group Moor House120 London WallLondonRG66BBUK

The frequency and duration of observed concurrent hot and dry events(HDes) over China during the growing season(April–September) exhibit significant decadal changes across the mid-1990s. These changes are characterized by increases in HDe frequency and duration over most of China, with relatively large increases over southeastern China(SeC), northern China(NC), and northeastern China(NeC). The frequency of HDes averaged over China in the present day(pD,1994–2011) is double that in the early period(ep, 1964–81);the duration of HDes increases by 60%. Climate experiments with the Met Office Unified Model(MetUM-GOML2) are used to estimate the contributions of anthropogenic forcing to HDe decadal changes over China. Anthropogenic forcing changes can explain 60%–70% of the observed decadal changes,suggesting an important anthropogenic influence on HDe changes over China across the mid-1990s. Single-forcing experiments indicate that the increase in greenhouse gas(GHG) concentrations dominates the simulated decadal changes,increasing the frequency and duration of HDes throughout China. The change in anthropogenic aerosol(AA) emissions significantly decreases the frequency and duration of HDes over SeC and NC, but the magnitude of the decrease is much smaller than the increase induced by GHGs. The changes in HDes in response to anthropogenic forcing are mainly due to the response of climatological mean surface air temperatures. The contributions from changes in variability and changes in climatological mean soil moisture and evapotranspiration are relatively small. The physical processes associated with the response of HDes to GHG and AA changes are also revealed.

关键词： concurrent hot and dry events decadal variation greenhouse gases aerosol emissions

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Brain dysfunctions and neurotoxicity induced by psychostimulants in experimental models and humans:an overview of recent findings

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Neural Regeneration Research 2024年第9期19卷 1908-1918页

作者： Marcello Serra Nicola Simola Alexia e.pollack Giulia Costa Department of Biomedical Sciences Section of NeuroscienceUniversity of CagliariCagliariItaly Department of Biology University of Massachusetts-BostonBostonMAUSA

preclinical and clinical studies indicate that psychostimulants,in addition to having abuse potential,may elicit brain dysfunctions and/or neurotoxic *** toxicity induced by psychostimulants may pose serious health risks since the recreational use of these substances is on the rise among young people and *** present review provides an overview of recent research,conducted between 2018 and 2023,focusing on brain dysfunctions and neurotoxic effects elicited in experimental models and humans by amphetamine,cocaine,methamphetamine,3,4-methylenedioxymethamphetamine,methylphenidate,caffeine,and *** elucidation of factors and mechanisms that underlie psychostimulant-induced brain dysfunction and neurotoxicity is crucial for understanding the acute and enduring noxious brain effects that may occur in individuals who use psychostimulants for recreational and/or therapeutic purposes.

关键词： 3,4-methylenedioxymethamphetamine amphetamine caffeine cell cultures cocaine methamphetamine methylphenidate neurotoxicity nicotine

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A novel method for modeling the phase change of iron ore particles in the cohesive zone of a blast furnace

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particuology 2024年第3期86卷 252-261页

作者： Dianyu e Yingming Wen Jiayun Dan Youyuan Jiang Guangchao Wei Jiaxin Cui Jiangxi provincial Key Laboratory for Simulation and Modelling of particulate Systems Jiangxi University of Science and TechnologyNanchang330013China international institute for innovation Jiangxi University of Science and TechnologyNanchang330013China ironmaking plant Xiangtan Iron and Steel Corporation of Hunan HualingXiangtan411101China Schoolof Transportation and Vehicle enginering Shandong University of TechnologyZibo255000China

Cohesive zone plays a vital role in the stable operation of a blast furnace(BF),yet the complex phase change process of iron ore particles in this zone is still not well *** this study,a novel one-dimensional(1D)unsteady phase change model was developed to elucidate the heat transfer and melting mechanisms of iron ore *** model validation,the effects of several key operating parameters(e.g.,particle diameter,gas velocity,initial temperature)on the phase change behavior of iron ore particles were analyzed,and the joint effect of multiple parameters was *** results show that larger-sized iron ore particles possess lower specific surface areas,which in turn reduces their convective heat absorption ***,the distance from the solid-liquid phase interface to the particle surface increases,thereby slowing down the movement of the phase interface and pro-longing the melting duration of the *** the gas velocity and the initial temperature does not have a significant impact on reducing the duration of the complete melting *** the specified conditions,it is observed that increasing the gas velocity by 3-fold and 9-fold results in a reduction of the melting duration by 2.4%and 8.3%,*** the initial temperature of iron ore particles results in a decrease in the core-to-surface temperature difference,a slower heating rate,and a shorter duration to achieve *** the factors affecting the melting process,the particle diameter is found to be the most significant in terms of the liquid phase precipitation,mushy zone thickness,and core-to-surface temperature difference of iron ore particles.

关键词： Blast furnace iron ore melting Cohesive zone Heat transfer phase change

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Cavitation research with computational fluid dynamics:From euler-euler to euler-Lagrange approach

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Journal of Hydrodynamics 2024年第1期36卷 1-23页

作者： Bin Ji Zi-yang Wang Huai-yu Cheng Rickard e.Bensow State Key Laboratory of Water Resources engineering and Management Wuhan UniversityWuhan430072China Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGothenburgSweden

Unsteady cavitating flow often contains vapor structures with a wide range of different length scales,from micro-bubbles to large cavities,which issues a big challenge to precisely investigate its evolution mechanism by computational fluid dynamics(CFD)*** present work reviews the development of simulation methods for cavitation,especially the emerging euler-Lagrange ***,the progress of the numerical investigation of hot and vital issues is discussed,including cavitation inception,cloud cavitation inner structure and its formation mechanism,cavitation erosion,and cavitation *** is indicated that the euler-Lagrange method can determine cavitation inception point *** cloud cavitation,the euler-Lagrange method can reveal the source of microbubbles and their distribution law inside the shedding *** method also has advantages and great potential in assessing cloud cavitation-induced erosion and *** the ever-growing demands of cavitation simulation accuracy in basic research and engineering applications,how to improve the euler-Lagrange method’s stability and applicability is still an open *** further promote the application of this advanced CFD simulation technology in cavitation research,some key issues are to be solved and feasible suggestions are put forward for further work.

关键词： numerical simulation euler-euler method euler-Lagrange method bubble dynamicsgy,Gothenburg,Sweden

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Artificial ground freezing of underground mines in cold regions using thermosyphons with air insulation

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international Journal of Mining Science and Technology 2024年第5期34卷 643-654页

作者： Ahmad F.Zueter Mohammad Zolfagharroshan Navid Bahrani Agus p.Sasmito Department of Civil and Resource engineering Dalhousie UniversityHalifax B3H4R2Canada Department of Mining engineering McGill UniversityMontreal H3A0E8Canada

Current practice of underground artificial ground freezing(AGF)typically involves huge refrigeration systems of large economic and environmental *** this study,a novel AGF technique is proposed deploying available cold wind in cold *** is achieved by a static heat transfer device called thermosyphon equipped with an air insulation layer.A refrigeration unit can be optionally integrated to meet additional cooling *** introduction of air insulation isolates the thermosyphon from ground zones where freezing is not needed,resulting in:(1)steering the cooling resources(cold wind or refrigeration)towards zones of interest;and(2)minimizing refrigeration *** design is demonstrated using well-validated mathematical models from our previous work based on two-phase enthalpy method of the ground coupled with a thermal resistance network for the *** Canadian mines are considered:the Cigar Lake Mine and the Giant *** results show that our proposed design can speed the freezing time by 30%at the Giant Mine and by two months at the Cigar Lake ***,a cooling load of 2.4 GWh can be saved at the Cigar Lake ***,this study provides mining practitioners with sustainable solutions of underground AGF.

关键词： Artificial ground freezing Underground mining Sustainable mining Thermosyphon Air insulation Cold regions

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performance and emission Characteristics of a CRDi Diesel engine Fuelled by SiO_(2) Nanoparticle-Waste Fat Biodiesel Blends

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China petroleum processing & petrochemical Technology 2024年第1期26卷 56-66页

作者： Babu Aurtherson p Dinesh Babu Munuswamy Ravikumar Jayabal Yuvarajan Devarajan Department of Mechanical engineering Mahat Amma Institute of Engineering and TechnologyPudukkottaiTamil NaduIndia Department of Mechanical engineering Rajalakshmi Institute of TechnologyChennaiTamil NaduIndia Department of Thermal engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical SciencesChennaiTamil NaduIndia

This study investigates the use of waste fat biodiesel(WFB)from the leather industry as a substitute for diesel ***,it examines the diesel engine performance of WFB,a blend of WFB and diesel(B50),and different blends of WFB and silicon dioxide(SiO_(2))nanoparticles(B50SiO_(2)40,B50SiO_(2)80,and B50SiO_(2)120μg/g).The results indicate that the B50SiO_(2)120 blend increases brake thermal efficiency by 10.03%compared to pure biodiesel but falls 1.93%short of neat ***,the B50SiO_(2)120 mixture reduces smoke,hydrocarbon,and carbon monoxide emissions by 31.87%,34.14%,and 43.97%respectively,compared to ***,the B50SiO_(2)120 blend shows a 4.91%increase in nitrogen oxide emissions compared to diesel.

关键词： waste fat transesterification biodiesel silicon dioxide emission

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pressurized environments directly influence friction and wear of dry steel contacts—investigations in a novel high fluid pressure tribometer

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Friction 2024年第7期12卷 1599-1617页

作者： paul ReiCHLe Jakob BARZ Georg UMLAUF Günter e.M.TOVAR institute of interfacial process engineering and plasma Technology(iGVp) University of StuttgartStuttgart 70569Germany Fraunhofer institute for interfacial engineering and Biotechnology(iGB) Stuttgart 70569Germany

To reduce the usage of classical lubricants in deep drawing,a new tribological system based on volatile lubricants was ***,a volatile medium is injected under high pressure into the interstice between drawing tool and sheet *** on temperature and pressure,the temporary lubricant may exist in its gaseous or liquid *** this study,a novel high fluid pressure tribometer was designed to investigate the friction and wear of dry steel contacts under comparable conditions like in dry deep ***,a new ball-on-disc tribometer was designed and integrated into a high-pressure *** specifically investigate the effects of different environments(technical air,liquid and gaseous carbon dioxide,nitrogen,argon)at atmospheric and high pressure(0.1 Mpa,6 Mpa)on tribology,the specimens and all components were operating *** the experiments,the friction was measured *** show that the highest friction occurs in air and the lowest in carbon dioxide *** to the experiments,the wear of the specimens was assessed along with changes in surface chemistry related to tribochemical ***,the tribology of the dry sliding contacts is correlated to changes of the surface *** differences as well as similarities regarding the different fluid environments are *** the results show,the differences between the media used are most pronounced at elevated ***,this work gives clear indications on the suitability of volatile lubricants in dry friction or rather gas lubrication,especially for dry deep drawing.

关键词： dry friction and dry wear gas lubrication carbon dioxide tribo-layer dry metal forming

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A low-noise,high-gain,and large-dynamic-range photodetector based on a JFeT and a charge amplifier

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Frontiers of information Technology & electronic engineering 2024年第2期25卷 316-322页

作者： Jinrong WANG Shuang'e WU Chengdong Mi Yaner QiU Xin'ai BAi Department of physics Lyuliang UniversityLvliang033001China Guangdong provincial Key Laboratory of Fiber Laser Materials and Applied Techniques South China University of TechnologyGuangzhou510640China

We demonstrate a low-noise,high-gain,and large-dynamic-range photodetector(pD)based on a junction field-effect transistor(JFeT)and a charge amplifier for the measurement of quantum noise in Bell-state detection(BSD).particular photodiode junction capacitance allows the silicon N-channel JFeT 2sk152 to be matched to the noise requirement for charge amplifier *** electronic noise of the pD is effectively suppressed and the signal-to-noise ratio(SNR)is up to 15 dB at the analysis frequency of 2.75 MHz for a coherent laser power of 50.08µ*** combining of the inductor and capacitance,the alternating current(AC)and direct current(DC)branches of the pD can operate linearly in a dynamic range from 25.06µW to 17.50 *** pD can completely meet the requirements of SNR and dynamic range for BSD in quantum optics experiments.

关键词： Quantum noise Bell-state detection(BSD) photodetector(pD) Junction field-effect transistor(JFeT) Charge amplifier

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