检索结果-南通市图书馆

Science China Mathematics 2024年第2期67卷 315-338页

作者： Shengda Zeng Akhtar A.khan Stanislaw Migórski Guangxi Colleges and Universities Key Laboratory of Complex System Optimization and Big Data Processing Yulin Normal UniversityYulin 537000China Faculty of Mathematics and Computer Science Jagiellonian University in Krak´owKrak´ow 30348Poland Center for Applied and Computational Mathematics School of Mathematical SciencesRochester Institute of TechnologyRochesterNY 14623USA College of Sciences Beibu Gulf UniversityQinzhou 535000China

In this paper, we study a generalized quasi-variational inequality (GQVI for short) with twomultivalued operators and two bifunctions in a Banach space setting. A coupling of the Tychonov fixedpoint principle and the Katutani-Ky Fan theorem for multivalued maps is employed to prove a new existencetheorem for the GQVI. We also study a nonlinear optimal control problem driven by the GQVI and givesufficient conditions ensuring the existence of an optimal control. Finally, we illustrate the applicability of thetheoretical results in the study of a complicated Oseen problem for non-Newtonian fluids with a nonmonotone andmultivalued slip boundary condition (i.e., a generalized friction constitutive law), a generalized leak boundarycondition, a unilateral contact condition of Signorini’s type and an implicit obstacle effect, in which themultivalued slip boundary condition is described by the generalized Clarke subgradient, and the leak boundarycondition is formulated by the convex subdifferential operator for a convex superpotential.

关键词： generalized quasi-variational inequality existence theorem optimal control Kakutani-Ky Fan theorem Oseen problem non-Newtonian fluid nonmonotone slip boundary condition

Development of anti-corrosive coating on AZ31 Mg alloy modified by MOF/LDH/PEO hybrids

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第2期12卷 586-607页

作者： Muhammad Ali khan Ananda Repycha Safira Mohammad Aadil Mosab Kaseem Corrosion and Electrochemistry Laboratory Department of Nanotechnology and Advanced Materials EngineeringSejong UniversitySeoul 05006Republic of Korea

The self-assembly of hybrid inorganic-organic materials on stationary platforms plays a critical role in improving their structural stability and wide *** this work,a novel two-step hydrothermal approach is proposed for synthesizing stable and advanced hybrid coatings on metal-oxide platforms through the surface modification of layered double hydroxide(LDH)films using novel metal-organic frameworks(MOFs).Initially,Mg-Al LDH nanocontainers,grown on a magnesium oxide layer produced through plasma electrolytic oxidation(PEO)of AZ31 Mg alloy substrate,were intercalated with cobalt via an oxidation route,providing the metallic coordination center for the MOF *** the subsequent step,a pioneering technique is introduced,utilizing tryptophan as the organic linker for the first time at a pH of *** self-assembly of cobalt-tryptophan complex,driven by the strong bonding between electrophilic sites of monomers and nucleophilic sites,facilitated the formation of a MOF network having a cloud-like structure on the surface of MgAl LDH's *** resulting MOF-LDH encapsulation containers demonstrate exceptional electrochemical stability when exposed to a 3.5 wt.%NaCl solution,surpassing the performance of PEO and pure LDH *** enhanced stability is attributed to the development of a dense top layer and a stable composition within the self-assembled MOF,effectively sealing flaws and preventing the infiltration of corrosive ions into the underlying metallic *** formation mechanism of MOFs on LDH galleries is investigated using density functional theory calculations.

关键词： Mg alloy Layered double hydroxide Metal-organic frameworks Corrosion DFT

Green hydrogen production from photovoltaic power station as a road map to climate change mitigation

在线全文

学校读者我要写书评

暂无评论

Clean Energy 2024年第2期8卷 156-167页

作者： Kehinde Ridwan Kamil Bassey Okon Samuel Umar khan Department of Computer Science and Engineering Edge Hill UniversityUK Enel Green Power Rome Italy Materials Research Laboratory Steelagon Engineering LimitedKaduna StateNigeria

The increasing recognition of hydrogen as a critical element in the global net-zero transition and its clear role in decarbonizing challenging sectors coincide with the growing urgency to address climate ***'s favourable renewable-energy capacity,ranging from 28%to 36%for solar,has been reported by the global solar irradiance ***,the majority of hydrogen production today relies on fossil fuels(96%),with only a small fraction(4%)being produced through water *** though there have been many studies on climate change mitigation with a focus on Africa,a green hydrogen production from a photovoltaic power station approach has not been ***,literature with a focus on Nigeria is *** study focuses on the African green hydrogen production industry,utilizing Nigeria as a case study to explore the feasibility of generating clean hydrogen vectors from a percentage of photovoltaic power output in various regions of the country through stand-alone solar grid electrification *** of the usage and effectiveness of the produced hydrogen fuel in each region are carried out,with the highest region having an annual output of 12247278 kg of green hydrogen and 8573094 kg of ammonia and the lowest region having an output of 511245 kg of green hydrogen and 357871 kg of ammonia,and the expected production from the proposed usage of 50%of the power generation output of the installed 1.6-MWp and 80-kWp solar power minigrids in the regions is *** analyses were repeated for the other considered regions in the *** results showcased the enormous advantages of the electrolytic production of hydrogen and how the greener economy project can play a major role in mitigating climate change effects and overreliance on fossil fuels as the driver of the economy in many African countries.

关键词： renewable energy photovoltaic climate change green hydrogen vector fossil fossil fuels decarbonization electrolysis

A new model of flow over stretching(shrinking)and porous sheet with its numerical solutions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2024年第3期39卷 381-397页

作者： Azhar Ali Dil Nawaz khan Marwat Saleem Asghar Department of Mathematics Islamia College Peshawar 25120Jamrod roadPeshawarKhyber PakhtunkhwaPakistan Department of Mathematics COMSATS Institute of Information TechnologyPark RoadTarlai KalanIslamabad 45550Pakistan

The viscous fluid flow and heat transfer over a stretching(shrinking)and porous sheets of nonuniform thickness are investigated in this *** modeled problem is presented by utilizing the stretching(shrinking)and porous velocities and variable thickness of the sheet and they are combined in a ***,the new problem reproduces the different available forms of flow motion and heat transfer maintained over a stretching(shrinking)and porous sheet of variable thickness in one *** a result,the governing equations are embedded in several parameters which can be transformed into classical cases of stretched(shrunk)flows over porous sheets.A set of general,unusual and new variables is formed to simplify the governing partial differential equations and boundary *** final equations are compared with the classical models to get the validity of the current simulations and they are exactly matched with each other for different choices of parameters of the current problem when their values are properly adjusted and ***,we have recovered the classical results for special and appropriate values of the parameters(δ_(1),δ_(2),δ_(3),c,and B).The individual and combined effects of all inputs from the boundary are seen on flow and heat transfer properties with the help of a numerical method and the results are compared with classical solutions in special *** is noteworthy that the problem describes and enhances the behavior of all field quantities in view of the governing *** result shows that the dual solutions can be found for different possible values of the shrinking parameter.A stability analysis is accomplished and apprehended in order to establish a criterion for the determinations of linearly stable and physically compatible *** significant features and diversity of the modeled equations are scrutinized by recovering the previous problems of fluid flow and heat transfer from a uniformly heated sheet

关键词： permeable stretching(shrinking)sheets sheet of variable thickness heat transfer numerical(dual)solutions stability analysis

Assessing gully erosion and rehabilitation using multi temporal LiDAR DEMs:Case study from the Great Barrier Reef catchments,Australia

在线全文

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2024年第1期12卷 184-199页

作者： Sana khan Rebecca Bartley Anne Kinsey-Henderson Aaron Hawdon The Commonwealth Scientific and Industrial Research Organisation(CSIRO) Environment1 James Cook DrDouglas4814Australia The Commonwealth Scientific and Industrial Research Organisation(CSIRO) EnvironmentGPO Box 2583BrisbaneQLD4001Australia

Millions of dollars are being spent on gully rehabilitation to help reduce excess fine sediment delivery to the Great Barrier Reef(GBR).There is an urgent need for(i)prioritisation of active gullies for rehabilitation and(ii)the development of methodologies to inform the effectiveness of *** this study we analyse DEMs of Difference derived from 0.5 m resolution 2-3 year interval multi-temporal LiDAR data collected pre and post rehabilitation at three variable gully morphologies in the Burdekin *** analysis indicates that the highest annual average fine sediment erosion rates for the untreated control gullies occur at the linear gully(53.38 t ha^(-1)y^(-1))followed by linear-alluvial gully(34.24 t ha^(-1)y^(-1))and least at the alluvial gully(14.41 t ha^(-1)y^(-1)).The proportional loss or export of fine sediment from the gullies in their un-treated condition ranges from∼68 to 90%of what is eroded,and when the gullies are treated the proportion of fine sediment that is retained in the gully proportional to what is eroded increases to∼60%at all *** pre-treatment baseline erosion rates,and additional post treatment LiDAR captures,it is difficult to quantify the treatment *** results offer insights in the erosion mechanisms within different geomorphic gully morphologies and rehabilitation effects in these erosional *** study provides crucial knowledge of gully dynamics that can be coupled with other lines of evidence for better prioritisation of rehabilitation in the GBR catchments.

关键词： Digital elevation models (dis)connectivity Restoration Geomorphic change detection Geomorphic effectiveness GIS

Flexible perovskite light-emitting diodes for display applications and beyond

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第5期45卷 8-25页

作者： Yongqi Zhang Shahbaz Ahmed khan Dongxiang Luo Guijun Li Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Huangpu Hydrogen Innovation Center/Guangzhou Key Laboratory for Clean Energy and Materials School of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou 510006China

The flexible perovskite light-emitting diodes(FPeLEDs),which can be expediently integrated to portable and wearable devices,have shown great potential in various *** FPeLEDs inherit the unique optical properties of metal halide perovskites,such as tunable bandgap,narrow emission linewidth,high photoluminescence quantum yield,and particularly,the soft nature of *** present,substantial efforts have been made for FPeLEDs with encouraging external quantum efficiency(EQE)of 24.5%.Herein,we summarize the recent progress in FPeLEDs,focusing on the strategy developed for perovskite emission layers and flexible electrodes to facilitate the optoelectrical and mechanical *** addition,we present relevant applications of FPeLEDs in displays and ***,perspective toward the future development and applications of flexible PeLEDs are also discussed.

关键词： metal halide perovskite flexible light-emitting diodes optical properties mechanical flexibility display

Energy-Efficient Implementation of BCD to Excess-3 Code Converter for Nano-Communication Using QCA Technology

在线全文

学校读者我要写书评

暂无评论

China Communications 2024年第6期21卷 103-111页

作者： Nuriddin Safoev Angshuman khan Khudoykulov Zarif Turakulovich Rajeev Arya Department of Cybersecurity&Criminology Tashkent University of Information TechnologiesTashkent 100084Uzbekistan Department of Electronics and Communication Engineering University of Engineering and ManagementJaipurRajasthan 303807India Department of Cryptology Tashkent University of Information TechnologiesTashkent 100084Uzbekistan Department of Electronics and Communication Engineering National Institute of Technology PatnaBihar 800005India

Code converters are essential in digital nano communication;therefore,a low-complexity optimal QCA layout for a BCD to Excess-3 code converter has been proposed in this paper.A QCA clockphase-based design technique was adopted to investigate integration with other complicated *** a unique XOR gate,the recommended circuit’s cell complexity has been *** findings produced using the QCADesigner-2.0.3,a reliable simulation tool,prove the effectiveness of the current structure over earlier designs by considering the number of cells deployed,the area occupied,and the latency as design *** addition,the popular tool QCAPro was used to estimate the energy dissipation of the proposed *** proposed technique reduces the occupied space by∼40%,improves cell complexity by∼20%,and reduces energy dissipation by∼1.8 times(atγ=1.5EK)compared to the current scalable *** paper also studied the suggested structure’s energy dissipation and compared it to existing works for a better performance evaluation.

关键词： BCD code converter Excess-3 nano communication QCA circuits

Assessing the impact of heat mitigation measures on thermal performance and energy demand at the community level:A pathway toward designing net-zero energy communities

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2024年第8期17卷 1379-1400页

作者： khan Rahmat Ullah Veljko Prodanovic Gloria Pignatta Ana Deletic Mattheos Santamouris School of Built Environment Faculty of ArtsDesign&ArchitectureUniversity of New South WalesSydney2052 NSWAustralia School of Civil and Environmental Engineering University of New South WalesSydney2052 NSWAustralia Institute for Artificial Intelligence Research and Development of Serbia 21000 Novi SadSerbia Institute for Multidisciplinary Research University of BelgradeKneza Višeslava 111000 BelgradeSerbia School of Civil and Environmental Engineering Engineering FacultyQueensland University of TechnologyQLD 4001Australia

In the context of escalating global energy demands,urban areas,specifically the building sector,contribute to the largest energy consumption,with urban overheating exacerbating this *** urban modelling for heat-mitigation and reduction of energy demand is crucial steps towards a sustainable built-environment,complementing onsite energy generation in the design and development of Net-zero Energy(NZE)Settlement,especially in the context of Australian weather *** a significant gap in existing literature,this study offers empirical analysis on the climate and energy efficacy of integrated heat mitigation strategies applied in 14 neighbourhood typologies located in Sydney,*** the application of cool materials on roads,pavements,and rooftops,alongside urban vegetation enhancement,the analysis demonstrates scenario effectiveness on heat mitigation that leads to reduce ambient temperature and energy demands along with CO_(2)emissions within the *** building arrangement,built-area ratio,building height,and locations,ENVI-met and CitySim are utilized to assess the heat-mitigation and the energy demand of neighbourhoods,*** indicate that mitigation measures can lead up to a 2.71℃reduction in ambient temperature and over 25%reduction in Cooling Degree Hours,with a 34.34%reduction in cooling energy demand and overall energy savings of up to 12.49%.In addition,the annual energy-saving yields a CO_(2)reduction of approximately 141.12 tonnes,where additional vegetation further amplifies these reductions by enhancing CO_(2)*** study showcases the pathway towards achieving NZE goals in climates similar to that of Australia,highlighting significant benefits in heat-mitigation,environmental impact,and energy-savings.

关键词： urban overheating cool materials vegetation,heat mitigation energy savings CO_(2)reduction

Effects of grain's shape-and size-polydispersities,orientation,and area fraction on tortuosity and permeability of 2D granular media

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第7期90卷 535-557页

作者： Ke Cao Huisu Chen Mohammad Iqbal khan Mingqi Li Lin Liu Jiangsu Key Laboratory of Construction Materials School of Materials Science and EngineeringSoutheast UniversityNanjing 211189China Department of Civil Engineering College of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia School of Civil and Transportation Engineering Hebei University of TechnologyTianjin 300401China College of Civil and Transportation Engineering Hohai UniversityNanjing210098China

The microstructure of granular media, including grain's shape- and size-polydispersities, orientation, and area fraction can potentially affect its permeability. However, few studies consider the coupling effects of these features. This work employs geometrical probability and stereology to establish quantitative relationships between the above microstructural features and the geometric tortuosity of the two-dimensional granular media containing superellipse, superoval, and polygon grains. Then the lattice Boltzmann method (LBM) is used to determine the permeabilities of these granular media. By combining the tortuosity model and the LBM-derived permeabilities, modified K–C equations are formulated to predict the permeability and the shape factor, considering the grain's shape- and size-polydispersities, orientation, and area fraction. The reliability of these methods can be verified by comparing them with both our simulations and available experimental, theoretical, and numerical data reported in the literature. The findings implicate that the tortuosity and permeability of the granular media are strongly correlated with the grain's shape, orientation, and area fraction but unaffected by the size polydispersity and spatial arrangement of grains. Only circularity is not enough to derive a unified formula for considering the impact of grain shape on tortuosity and permeability, other shape parameters need to be explored in the future.

关键词： Geometric tortuosity Konzey-Carman equation Shape and size ploydispersities Grain orientation Lattice Boltzmann method Granular media

Deciphering the role of rGO in tuning dielectric properties of Er_(2)O_(3)/ZnO/rGO nanocomposites synthesized via facile approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第3期42卷 578-585,I0006页

作者： Saiqa Hafeez Saima Perveen Muhammad Zarrar khan Awab Hashmi Fahad Azad School of Natural Sciences(SNS) National University of Sciences and Technology(NUST)IslamabadPakistan Electronic and Magnetic Materials Laboratory School of Chemical and Materials Engineering(SCME)National University of Sciences and Technology(NUST)IslamabadPakistan

The present research investigated the effect of reduced graphene oxide(rGO) integration with assynthesized Er_(2)O_(3)/ZnO nanocomposites on dielectric properties. The samples were characterized by Xray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), diffuse reflectance spectroscopy(DRS), and energy dispersive spectroscopy(EDS). Complex impedance spectroscopy was utilized to characterize dielectric relaxation phenomena in Er_(2)O_(3)/ZnO and Er_(2)O_(3)/ZnO/rGO nanocomposites. All the samples exhibit single relaxation phenomena which are ascribed to grain boundaries. The addition of rGO to Er_(2)O_(3)/ZnO nanocomposite results in the enhancement of dielectric response due to increased local field intensity caused by the formation of conductinginsulating interfaces. Furthermore, the AC conductivity of the Er_(2)O_(3)/ZnO/rGO is increased at higher frequencies due to the presence of free charge carriers in rGO. At higher frequencies, Er_(2)O_(3)/ZnO/rGO nanocomposite with increased concentration of ZnO exhibits a more stable dielectric constant with extremely low dielectric loss. Hence, the inclusion of rGO in Er_(2)O_(3)/ZnO nanocomposites makes it a novel prospective candidate in the field of energy storage devices.

关键词： Erbium oxide(Er_(2)O_(3)) Rare earths Stable dielectric constant Impedance Polarization Grain boundaries