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Glycine-nitrate auto-combustion synthesis and magnetic properties of nanocrystalline ndAl_(x)Fe_(1-x)O_(3) perovskites

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Journal of Rare earths 2023年第1期41卷 108-115页

作者： e.A.nforna HJ.M.ngantchou J.n.Ghogomu Department of Fundamental Science Higher Technical Teacher Training CollegeUniversity of BamendaP.O.Box 39BambiliCameroon Department of Chemistry Faculty of SciencesUniversity of DoualaP.O.Box 24157DoualaCameroon Department of Chemistry The University of BamendaP.O.Box 39BambiliCameroon Department of Chemistry University of DschangP.O.Box 67DschangCameroon

The effect of substitution of Fe^(3+) by Al^(3+) on the structure and magnetic properties of ndAl_(x)Fe_(1-x)O_(3) perovskite nano-powders(x=0.0,0.1,0.2,0.3,0.4,and 0.5) prepared by the glycine-nitrate auto-combustion method was *** samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SeM),Fourier transform infrared spectroscopy(FT-IR),and energy dispersive X-ray spectroscopy(eDX).The magnetic properties of the samples were investigated using a vibrating sample magnetometer(VSM).The X-ray results for all samples reveal the formation of an orthorhombic perovskite phase(space group pbnm) with no secondary *** crystallite sizes of the nanoparticles are found to decrease with increasing Al content,and are in the range of 53-38 *** images show spherical nanoparticles with *** FT-IR spectra confirm the presence of metal oxygen *** M-H loop of the pristine ndFeO_(3) sample is antiferromagnetic in the a b plane with weak ferromagnetism in the *** AI inclusions in the pristine polycrystal thereby creating magnetic vacancies is seen to influence the magnetic *** magnetic dilution results in enhanced magnetisation at low Al content;x=0.1,0.2(saturation magnetisation being 2.08 and 2.05 emu/g,respectively) compared to the pristine sample with a saturation magnetisation of 1.43 emu/g due to increased exchange *** dilution with nonmagnetic dopant induces the phase transition from weak ferromagnetic to paramagnetic depending on the impurity *** coercive field for ndFeO_(3) is found to be equal to 1950 Oe and decreases with *** findings lay a ground work for research in tuning magnetic properties and in spintronics with potential applications in data storage,switches and electronic devices.

关键词： Anti-ferromagnetism Weak ferromagnetism Orthorhombic ndAl_(x)Fe_(1-x)O_(3) perovskite nanopowders Magnetic dilution

nonstationary fuzzy forecasting of wind and wave climate in very long-term scales

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Journal of Ocean engineering and Science 2018年第2期3卷 144-155页

作者： Ch.n.Stefanakos e.Vanem SInTeF Ocean Department of Energy and TransportPostboks 4762 TorgardenTrondheim NO-7465Norway DnV GL Group Technology and ResearchP.O Box 3001322HøvikNorway

Global climate change may have serious impact on human activities in coastal and other *** change may affect the degree of storminess and,hence,change the wind-driven ocean wave *** may affect the risks associated with maritime activities such as shipping and offshore oil and ***,there is a recognized need to understand better how climate change will affect such ***,such understanding comes from future projections of the wind and wave climate from numerical climate models and from the stochastic modelling of such *** work investigates the applicability of a recently proposed nonstationary fuzzy modelling to wind and wave climatic *** to this,fuzzy inference models(FIS)are coupled with nonstationary time series modelling,providing us with less biased climatic *** long-term datasets for an area in the north Atlantic Ocean are used in the present study,namely nORA10(57 years)and exWaCli(30 years in the present and 30 years in the future).Two distinct experiments have been performed to simulate future values of the time series in a climatic *** assessment of the simulations by means of the actual values kept for comparison purposes gives very good results.

关键词： Fuzzy time series Wind and wave data Forecasting nonstationary Ocean wind and wave climate

Context-Aware practice problem Recommendation Using Learners’ Skill Level navigation patterns

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Intelligent Automation & Soft Computing 2023年第3期35卷 3845-3860页

作者： p.n.Ramesh S.Kannimuthu Computer Science and engineering Karpagam Institute of TechnologyCoimbatore641105India Information Technology Karpagam College of EngineeringCoimbatore641032India

The use of programming online judges(pOJs)has risen dramatically in recent years,owing to the fact that the auto-evaluation of codes during practice motivates students to learn *** pOJs have greater number of pro-gramming problems in their repository,learners experience information *** systems are a common solution to information *** recommender systems used in e-learning platforms are inadequate for pOJ since recommendations should consider learners’current context,like learning goals and current skill level(topic knowledge and difﬁculty level).To overcome the issue,we propose a context-aware practice problem recommender system based on learners’skill level navigation *** system initially performs skill level navigation pattern mining to discover frequent skill level navigations in the pOJ and toﬁnd learners’learning ***ﬁltering(CF)and con-tent-basedﬁltering approaches are employed to recommend problems in the cur-rent and next skill levels based on frequent skill level navigation *** sequence similarity measure is used toﬁnd the top k neighbors based on the sequence of problems solved by the *** experiment results based on the real-world pOJ dataset show that our approach considering the learners’cur-rent skill level and learning goals outperforms the other approaches in practice problem recommender systems.

关键词： Recommender systems skill level navigation pattern programming online judge collaborativeﬁltering content-basedﬁltering

Assessing Sustainability of Land Management Using a Risk Identification Model

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pedosphere 2003年第1期13卷 41-48页

作者： p.R.STepHenS A.e.Hewitt 等 LandcareResearch PrivateBag11052PalmerstonNorth（NewZealand） LandcareResearch.p.O.Box69 Lincoln（NewZealand）

new Zealand is highly dependent on its soil resource for continued agricultural production. To avoiddepleting this resource, there is a need to identify soils and associated land management practices wherethere is a risk of soil degradation. environmental integrity and ecosystem services also need to be ***, to ensure sustainable production, the on- and off-site environmental impacts of land managementneed to be identified and managed. We developed a structural vulnerability index for new Zealand soils. Thisindex ranks soils according to their inherent susceptibility to physical degradation when used for agricultural(pasture, forestry and cropping) purposes. We also developed a rule-based model to assess soil compactionvulnerability by characterising the combined effects of resistance and resilience. Other soil attributes havebeen appraised using seven chemical, physical and biological indicators of soil quality. These indicators havebeen applied in a nation-wide project involving data collection from over 500 sites for a range of land *** soil quality data can be interpreted via the World Wide Web - through the interactive decision-support tool SInDI. The land-use impact model is a framework to assess agricultural land management andenvironmental sustainability, and may be applied to land units at any scale. Using land resource data andinformation the model explicitly identifies hazards to land productivity and environmental integrity. It utilisesqualitative expert and local knowledge and quantitative model-based evaluations to assess the potentialenvironmental impacts of land-management practices. The model is linked to a geographic informationsystem (GIS), allowing model outputs, such as the environmental impacts of site-specific best managementpractices, to be identified in a spatially explicit manner. The model has been tested in new Zealand in anarea of pastoral land use. Advantages of this risk identification model include: utilising

关键词： land-use planning soil quality resilience resistance sustainableagriculture

A new fast swelling poly[DApB-co-DMAAm-co-AASS] superabsorbent hydrogel for removal of anionic dyes from water

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Chinese Chemical Letters 2013年第11期24卷 1005-1007页

作者： Yatin n.patel Manish p.patel Department of Chemistry Sardar Patel University

The objective of this research is to utilize a new poly[n,n-diallyl pyrrolidinium bromide-co-n,ndimethyl acrylamide-co-acrylic acid sodium salt]superabsorbent hydrogel（SAH）for the removal of two anionic dyes,e.g.,Reactive Red 5B（RR5B）and Reactive Orange M2R（ROM2R）,from *** SAH was characterized by swelling in water,FTIR,TGA and *** SAH DDA6showed good swelling property and thermal *** have also investigated the parameters affecting dye adsorption such as pH,adsorbent dose,adsorption rate and initial dye *** experimental data were also analyzed by applying the well known Langmuir and Freundlich isotherm models.

关键词： Superabsorbent hydrogel Anionic dyes Dye adsorption Adsorption isotherm

endoscopic difficulties in the diagnosis of upper gastrointestinal bleeding

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World Journal of Gastroenterology 2001年第3期7卷 308-312页

作者： M.n.Appleyard C.p.Swain Department of Gastroenterology Barts and The London NHS TrustLondon E1 1BBUK

InTRODUCTIOnBleeding from the upper gastrointestinal ( GI ) tract remains common ,with a reported annual incidence of up to 172 per 100 000 [1],which has of anything increased from earlier series. Case fatality was recently reported as 14%[2] ,which has probably not changed over several decades .These figures may reflect a rising proportion of elderly patients and increasing non 杝teroidal anti-inflammatory use ,but occur despite apparently better treatments and understanding of the underlying pathophysiology of peptic ulcer disease.

关键词： Angiodysplasia endoscopy, Gastrointestinal Gastrointestinal Hemorrhage Humans

emission colour tuning in KLnF_(4):Yb^(3+),er^(3+)/Ho^(3+)phosphor

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Journal of Rare earths 2024年第1期42卷 57-65,I0002页

作者： Janani K Gayathri e Vijayatha V Ramasubramanian S Thiyagarajan p Department of Science and Humanities Nehru Institute of TechnologyKaliapuramThirumalayampalayamCoimbatoreIndia Department of Sciences Amrita School of Physical SciencesAmrita Vishwa VidyapeethamCoimbatoreIndia Department of physics Anna UniversityChennaiIndia

KLnF_(4):Yb^(3+),er^(3+)/Ho^(3+)(Ln=Y,Yb,Gd)phosphors were prepared by solid-state reaction *** each of the Yb^(3+)/er^(3+)and Yb^(3+)/Ho^(3+)co-doped phosphors independently,phase confirmation and morphological examination were accomplished using the X-ray diffraction technique and scanning electron microscope analysis.X-ray photoelectron spectroscopy analysis shows the charge state and existence of lanthanides and *** luminescence emissions of green and red colour were detected for the synthesized *** changes in the upconverted emission intensities and colour output pertaining to the change of the lanthanide host matrix along with dopants were investigated for the prepared *** the upconversion luminescence,erbium-doped samples exhibit a predominance of red emission while holmium-doped samples display a prevalence of green *** rare-earth er/Ho doped KYbF4shows strong red emission compared to other ***_(4):Yb,er/Ho exhibits relatively significant green upconve rsion emissions,while Yb,er-doped KGdF_(4)host displays a 10-fold increase in green/red emission ratio with an increase in the input power of 20-780 *** photoluminescence studies and decay curve analysis were carried out using UV light excitation for the developed phosphors.A higher lifetime of 2.2 ms was measured for the downshifting red emission in the Ho doped KYbF_(4)*** study suggests a potential for colour tunability in the upconversion and downshifting emissions through host modifications to the fluoride phosphor.

关键词： Rare earths energy transfer upconversion Downshifting Colour coordinates

One-Generated nilpotent Bicommutative Algebras

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Algebra Colloquium 2022年第3期29卷 453-474页

作者： Ivan Kaygorodov pilar páez-Guillán Vasily Voronin Centro de Matemática e Aplicacōes Universidade da Beira InteriorCovilhãPortugal Institute of Mathematics and Mathematical ModelingAlmatyKazakhstan University of Santiago de Compostela Santiago de CompostelaSpain University of ViennaViennaAustria novosibirsk State University NovosibirskRussia

We give a classification of 5-and 6-dimensional complex one-generated nilpotent bicommutative algebras.

关键词： bicommutative algebras nilpotent algebras algebraic classification central extension

Revealing microstructural evolution and mechanical properties of resistance spot welded niTi-stainless steel with ni or nb interlayer

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Journal of Materials Science & Technology 2024年第13期180卷 160-173页

作者： K.Zhang A.Shamsolhodaei A.Ghatei-Kalashami J.p.Oliveira C.Zang n.Schell J.Li A.R.H.Midawi J.G.Lopes J.Yan p.e.J.Rivera-Díaz-del-Castillo p.peng Y.n.Zhou Department of Mechanical and Mechatronics engineering University of Waterloo200 University Avenue WestWaterlooONN2L 3G1Canada CenIMAT/I3n Department of Materials ScienceNOVA School of Science and TechnologyUniversidade NOVA de Lisboa2829-516CaparicaPortugal Materials Research Group Department of Mechanical EngineeringUniversity of SouthamptonSouthamptonSO171BJUK Helmholtz-Zentrum Hereon Institute of Materials PhysicsMax-Planck-Str.1Geesthacht21502Germany UnIDeMI Department of Mechanical and Industrial EngineeringNOVA School of Science and TechnologyUniversidade NOVA de Lisboa2829-516CaparicaPortugal

Dissimilar welding of niTi and stainless steel(SS)for multifunctional device fabrication is challenging due to the brittle nature of intermetallic compounds(IMCs)that are formed in the weld *** this work,ni and nb interlayers were applied for the resistance spot welding(RSW)of niTi and SS to replace the harmful Fe_(2)Ti phase and to restrict the mixing of dissimilar molten metals,*** evolution and mechanical properties of the joints were *** was shown that a conventional weld nugget was created in the absence of any interlayer in the welded joint suffering from traversed cracks due to the formation of brittle IMCs network in the fusion zone(FZ).By the addition of ni from the interlayer,Fe_(2)Ti dominated weld nugget was efficaciously replaced by ni_(3)Ti phase;however,the presence of the large pore and cracks reduced the effective joining *** use of a nb interlayer resulted in a fundamentally different joint,in which FZs at niTi and SS sides separated by the unmolten nb would suppress the mixing of dissimilar molten ***-containing eutectic structures with low brittleness formed at the interfaces,contributing to the enhancement of joint strength(increased by 38%on fracture load and 460%on energy absorption).A high-melting-point interlayer showed great potential to realize a reliable and high-performing RSWed niTi-SS joint.

关键词： niTi Stainless steel Resistance spot welding Intermetallic compounds Mechanical properties