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solutions to semilinear p-Laplacian Dirichlet problem in population dynamics

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Applied Mathematics and Mechanics(English Edition) 2010年第2期31卷 247-254页

作者： R.A.MAsHIYEV1 G.ALIsOY s.OGRAs Department of Mathematics Dicle University Department of Mathematical sciences Inonu University

In this article, we study a semilinear p-Laplacian Dirichlet problem arising in population dynamics. We obtain the Morse critical groups at zero. The results show that the energy functional of the problem is trivial. ... 详细信息

关键词： p-Laplacian sign-changing weight function Morse critical groups

A hyperbolic Lindstedt-Poincare method for homoclinic motion of a kind of strongly nonlinear autonomous oscillators

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Acta Mechanica sinica 2009年第5期25卷 721-729页

作者： Y.Y.Chen s.H.Chen K.Y.sze Department of Applied Mechanics and Engineering sun Yat-sen University Department of Mechanical Engineering The University of Hong Kong Department of Applied Mechanics and Engineering Sun Yat-sen University

A hyperbolic Lindstedt-Poincare method is presented to determine the homoclinic solutions of a kind of nonlinear oscillators, in which critical value of the homoclinic bifurcation parameter can be determined. The generalized Lienard oscillator is studied in detail, and the present method＇s predictions are compared with those of Runge-Kutta method to illustrate its accuracy.

关键词： Lindstedt-Poincare method Hyperbolic function Nonlinear autonomous oscillator - Homoclinic orbit

Anthropogenic mineral generation and its potential resource supply:The case of niobium

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science China Earth sciences 2024年第8期67卷 2583-2591页

作者： Xianlai ZENG Moisés Gómez Mahmoud BAKRY Yong GENG Jinhui LI school of Environment Tsinghua UniversityBeijing 100084China school of Environmental science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China school of International and Public Affairs Shanghai Jiao Tong UniversityShanghai 200030China

The strategy of carbon neutrality is reshaping the global landscape of resource flow and *** the final sink of geological minerals,the proliferated anthropogenic minerals,also called secondary resources,play an increasingly important role in resource supply *** is a critical metal that lacks full concern for its *** fundamental principle of niobium circularity is to recycle and maintain the material as close to the manufacturing process as *** we estimate the niobium-containing applications lost at their end-of-life,underscoring the imperative to minimize such ***,we elucidate the extraction processes for scrap and alloy quantities throughout the industry's *** from anticipated waste generated by the majority of niobium applications,a forecast indicates a potential loss of approximately 168 kt by 2090 in the absence of ***,with a recycling efficiency of 90%for niobium,the projected loss diminishes to approximately 16 *** delve into the significance of niobium's circular economy and explore various aspects that demand further investigation for a seamless transition from linear to circular practices.

关键词： Niobium Anthropogenic mineral Circular economy Recycling sustainability

Predicting the effect of climate change on a range-restricted lizard in southeastern Australia

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Current Zoology 2018年第2期64卷 165-171页

作者： Bezeng s. BEZENG solomon G. TEsFAMICHAEL Buddhi DAYANANDA African Centre for DNA Barcoding Department of Botany and Plant Biotechnology University of Johannesburg P0Box 524 APK Campus 2006 Johannesburg South Africa Department of Geography Environmental Managementand Energy Studies University of Johannesburg P0 Box 524 APK Campus 2006 Johannesburg South Africa school of Life sciences University of Technology Sydney Broadway NSW 2007 Australia

Climate change is ranked as one of the most severe threats to global biodiversity. This global phenomenon is particularly true for reptiles whose biology and ecology are closely linked to climate. In this study, we used over 1,300 independent occurrence points and different climate change emission scenarios to evaluate the potential risk of changing climatic conditions on the current and future potential distribution of a rock-dwelling lizard; the velvet gecko. Furthermore, we investigated if the current extent of protected area networks in Australia captures the full range distribution of this species currently and in the future. Our results show that climate change projections for the year 2075 have the potential to alter the distribution of the velvet gecko in southeastern Australia. specifically, climate change may favor the range expansion of this species to encompass more suitable habitats. The trend of range expansion was qualitatively similar across the different cli- mate change scenarios used. Additionally, we observed that the current network of protected areas in southeast Australia does not fully account for the full range distribution of this species currently and in the future. Ongoing climate change may profoundly affect the potential range distribution of the velvet gecko population. Therefore, the restricted habitat of the velvet geckos should be the focus of intensive pre-emptive management efforts. This management prioritization should be extended to encompass the increases in suitable habitats observed in this study in order to maximize the microhabitats available for the survival of this species.

关键词： bioclirnatic variables climate change environmental niche models range expansion reptiles.

An Efficient stacked-LsTM Based User Clustering for 5G NOMA systems

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Computers, Materials & Continua 2022年第9期72卷 6119-6140页

作者： s.Prabha Kumaresan Chee Keong Tan Yin Hoe Ng Faculty of Engineering Multimedia UniversityCyberjaya63100Malaysia school of Information Technology Monash UniversitySubang Jaya47500Malaysia

Non-orthogonal multiple access(NOMA)has been a key enabling technology for the fifth generation(5G)cellular *** on the NOMA principle,a traditional neural network has been implemented for user clustering(UC)to maximize the NOMA system’s throughput performance by considering that each sample is independent of the prior and the subsequent ***,the prediction of UC for the future ones is based on the current clustering information,which is never used again due to the lack of memory of the ***,to relate the input features of NOMA users and capture the dependency in the clustering information,time-series methods can assist us in gaining a helpful insight into the *** its mathematical complexity,the essence of time series comes down to examining past behavior and extending that information into the ***,in this paper,we propose a novel and effective stacked long short term memory(s-LsTM)to predict the UC formation of NOMA users to enhance the throughput performance of the 5G-based NOMA *** the proposed strategy,the s-LsTM is modelled to handle the time-series input data to improve the predicting accuracy of UC of the NOMA users by implementing multiple LsTM layers with hidden *** implemented LsTM layers have feedback connections that help to capture the dependency in the clustering information as it propagates between the ***,we develop,train,validate and test the proposed model to predict the UC formation for the futures ones by capturing the dependency in the clustering information based on the time-series *** results demonstrate that the proposed scheme effectively predicts UC and thereby attaining near-optimal throughput performance of 98.94%compared to the exhaustive search method.

关键词： Non-orthogonal multiple access(NOMA) deep neural network(DNN) long short term memory(LsTM) temporal channel user clustering

Wind power potential over northern south America using ERA5-Land global reanalysis

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Clean Energy 2024年第2期8卷 104-112页

作者： Heli A.Arregocés Guillermo J.Bonivento Roberto Rojano Grupo de Investigación GIsA Facultad de IngenieríaUniversidad de La GuajiraRiohachaColombia Grupo Procesos Fisicoquímicos Aplicados Facultad de IngenieríaUniversidad de Antioquia SIU/UdeACalle 70 No.52-21MedellínColombia

The northernmost region of south America has great potential for wind energy production and is a strategic area for the energy tran*** analysed data from ERA5-Land global reanalysis from 1980 to 2020 to determine the wind power potential in this *** aim was to identify areas with a high potential for wind energy that could be used to supply energy in case of drought in the region or increases in fuel *** compared data from 19 meteorological stations located in Colombia with ERA5-Land reanalysis data to generate reliable information for the feasibility and operation of wind *** to our analysis,the Colombian Caribbean and Coastal Plain have monthly average wind speeds at 90 m ranging from 4.85 to 10.34 m/s and 3.79 to 6.62 m/s,*** on wind power density calculations,these regions have the highest wind power density in our study,with a monthly average of between 250 and 399 W/m^(2).The Caribbean Region had a 69%increase in wind power density from January to July compared with the annual *** wind power density in the plains increased from January to March,while the Mountain Region had higher anomalies from May to *** Alta Guajira and ParaguanáPeninsula have great potential to generate wind energy due to their privileged geographical *** ERA5 offers valuable information about wind availability in time and space,it cannot represent the influence of local effects on wind patterns for the Mountain Region.

关键词： onshore wind power wind power potential ERA5-Land global reanalysis wind speed

Effect of External Forced Flow and Boiling Film on Heat Transfer of AIsI 4140 steel Horizontal Rod During Direct Quenching

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Journal of Iron and steel Research International 2011年第10期18卷 34-41页

作者： A H Meysami R Ghasemzadeh s H seyedein M R Aboutalebi Department of Metallurgy and Material Engineering Golpayegan University Centre of Excellent for Advanced Material and Processing School of Metallurgy and Material EngineeringIran University of Science and Technology

The effects of rod falling and moving, external flow field, boiling film and radiation were investigated on fluid flow and heat transfer of AIsI 4140 steel horizontal rod during direct quenching by mathematical modeling. The flow field and heat transfer in quenching tank were simulated by computational fluid dynamics （CFD） method considering falling and moving of rods during process. Therefore, modeling of flow field was done by a fixed-mesh method for general moving objects equations, and then, energy equation was solved with a numerical approach so that effeet of boiling film heat flux was considered as a source term in energy equation for solid-liquid boundary. simulated results were verified by comparing with published and experimental data and there was a good agreement between them. Also, the effects of external forced flow and film boiling were investigated on heat flux output, temperature distribution and heat transfer coefficient of rod. Also simulated results determined optimum quenching time for this process.

关键词： direct quenching AIsI 4140 moving object heat transfer modeling

Infectious disease-resistant pigs: Will they fly?

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Journal of Integrative Agriculture 2021年第1期20卷 1-3页

作者： Tad s.sONsTEGARD Perry B.HACKETT Acceligen 3388 Mike Collins Drive suite#1 EaganMN 55121USA Center for Genome Engineering Deptement of GeneticsCell Biology and DevelopmentUniversity of MinnesotaMinneapolisMN 55455USA

Cloven hoof animals have been a major source of nutritious animal protein for humans for at least 10 000 years. Over this time many were domesticated into livestock and some were put under selection for traits of importance or cultural preference. Accompanying domestication, diseases were transmitted from livestock to humans as a result of living in close quarters.

关键词： diseases resistant livestock

Diffusion behavior of Cr in gradient nanolaminated surface layer on an interstitial-free steel

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Journal of Materials science & Technology 2019年第3期35卷 460-464页

作者： s.L.Xie Z.B.Wang K.Lu shenyang National Laboratory for Materials science Institute of Metal Research Chinese Academy of Sciences school of Materials science and Engineering University of Science and Technology of China

Nanolaminated structures composed of low-angle grain boundaries(LAGBs) possess high thermal stability. In this paper, a gradient nanolaminated(GNL) surface layer with smooth finish was fabricated on an interstitial-free steel by means of surface mechanical rolling treatment. Microstructural observations demonstrated that the average lamellar thickness is about 80 nm in the topmost surface layer and increases with increasing depth. High thermal stability was confirmed in the GNL surface layer after annealing at 500℃. Diffusion measurements showed that effective diffusivity of Cr in GNL layer is 4–6 orders of magnitude higher than lattice diffusivity within the temperature range from 400 to 500℃. This might be attributed to numerous LAGBs or dislocation structures with a higher energy state in the GNL surface layer. This work demonstrates the possibility to advanced chromizing(or other surface alloying)processes of steels with formation of GNL surface layer, so that a thicker alloyed surface layer with a stable nanostructure is achieved.

关键词： Gradient nanolaminated structure Interstitial-free steel Diffusion Low-angle grain boundary surface mechanical rolling treatment