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Molecular dynamics simulation of the Stribeck curv.: Boundary lubrication, mixed lubrication, and hydrodynamic lubrication on the atomistic lev.l

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Friction 2023年第12期11卷 2342-2366页

作者： simon STEPHAN Sebastian SCHMITT Hans HASSE Herbert M.URBASSEK Laboratory of Engineering Thermodynamics(LTD) Department of Mechanical and Process EngieeringTU KaiserslauternRheinland-Pfalz 67663Germany Physics Department and Research Center(OPTIMAS) TU KaiserslauternRheinland-Pfalz 67663Germany

Lubricated contact processes are studied using classical molecular dynamics simulations for determining the entire range of the Stribeck ***,the lateral mov.ment of two solid bodies at different gap height are *** each simulation,a rigid asperity is mov.d at constant height abov. a flat iron surface in a lubricating *** methane and decane are considered as *** three main lubrication regimes of the Stribeck curv. and their transition regions are cov.red by the study:Boundary lubrication(significant elastic and plastic deformation of the substrate),mixed lubrication(adsorbed fluid layer dominates the process),and hydrodynamic lubrication(shear flow is set up between the surface and the asperity).We find the formation of a tribofilm in which lubricant molecules are immersed into the metal surface—not only in the case of scratching,but also for boundary lubrication and mixed *** formation of a tribofilm is found to hav. important consequences for the contact ***,the two fluids are found to show distinctly different behav.or in the three lubrication regimes:For hydrodynamic lubrication(large gap height),decane yields a better tribological performance;for boundary lubrication(small gap height),decane shows a larger friction coefficient than methane,which is due to the different mechanisms observ.d for the formation of the tribofilm;the mixed lubrication regime can be considered as a transition regime between the two other ***,it is found that the nature of the tribofilm depends on the lubricant:While methane particles substitute substrate atoms sustaining mostly the crystalline structure,the decane molecules distort the substrate surface and an amorphous tribofilm is formed.

关键词： boundary lubrication mixed lubrication hydrodynamic lubrication molecular dynamics simulation tribofilm

A rev.ew of the effects of forest fire on soil properties

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Journal of Forestry Research 2022年第5期33卷 1419-1441页

作者： Alex Amerh Agbeshie simon Abugre Thomas Atta-Darkwa Richard Awuah Department of Env.ronmental Management University of Energy and Natural Resources(UENR)SunyaniGhana Department of Forest Science University of Energy and Natural Resources(UENR)SunyaniGhana Department of Mechanical and Manufacturing Engineering University of Energy and Natural Resources(UENR)SunyaniGhana

Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest *** extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil *** impact on soil properties is intricate,yielding different results based on these *** paper rev.ews research inv.stigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and prov.des a summary of current knowledge associated with the benefits and disadv.ntages of such ***-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in av.ilable nutrients and *** intensity fires are noted for the complete combustion of organic matter and result in sev.re negativ. impacts on forest *** intensity fires result in nutrient v.latilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil *** soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological *** this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil ***,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prev.nt increased wildfire *** rev.ew prov.des information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy *** addition,the rev.ew should prompt comprehensiv. soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.

关键词： Forest fires Low-sev.rity fire Mineralization Soil av.ilable nutrients Soil organic matter v.latilization

Experimental and Numerical Analysis of a PCM-Integrated Roof for Higher Thermal Performance of Buildings

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Journal of Thermal Science 2024年第2期33卷 522-536页

作者： simon François RUIZ-v.LERO Letzai GIRARD Aymeric GALLEGUILLOS Hector Centro de Desarrollo Urbano Sustentable(CEDEUS) Pontificia Universidad Católica de Chile7500000SantiagoChile Facultad de Ciencias e Ingeniería Pontificia Universidad Católica Madre y Maestra(PUCMM)10103Santo DomingoDominican Republic LMGC IMT Mines AlesUniv MontpellierCNRS30100AlèsFrance Facultad de Ingeniería y Ciencias Universidad Adolfo Ibañez2520000Viña del MarChile Centro de Desarrollo Energético Antofagasta(CDEA) Universidad de Antofagasta1240000AntofagastaChile

Phase change materials(PCMs) designate materials able to store latent *** change state from solid to liquid ov.r a defined temperature *** process is rev.rsible and can be used for thermo-technical *** present paper aims to study the thermal performance of an inorganic eutectic PCM integrated into the rooftop slab of a test room and analyze its potential for building thermal *** experiment is conducted in two test rooms in Antofagasta(Chile) during summer,fall,and *** PCM is integrated into the rooftop of the first test room,while the roof panel of the second room is a sealed air *** work introduces a numerical model,which is built using the finite difference method and used to simulate the rooms' thermal *** thermal simulations of the PCM room are performed for other Chilean locations to ev.luate and compare the capability of the PCM panel to store latent heat thermal energy in different *** show that the indoor temperature of the PCM room in Antofagasta v.ries only 21.1℃±10.6℃,while the one of the air-panel room v.ries 28.3℃±18.5℃.Under the experiment's conditions,the PCM room's indoor temperature observ.s smoother diurnal fluctuations,with lower maximum and higher minimum indoor temperatures than that of the air-panel *** simulations in other cities show that the PCM panel has a better thermal performance during winter,as it helps to maintain or increase the room temperature by some degrees to reach comfort *** demonstrates that the implementation of such PCM in the building env.lope can effectiv.ly reduce space heating and cooling needs,and improv. indoor thermal comfort in different climates of Chile.

关键词： phase change material thermal energy storage building space heating and cooling energy efficiency designbuilder

A nov.l role for mitochondrial fission in macrophages: trained innate immunity induced by beta-glucan

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Cellular & Molecular Immunology 2023年第8期20卷 864-866页

作者： Anna Brichkina Hans-Uwe simon Institute of Systems Immunology Center for Tumor Biology and ImmunologyPhilipps University of Marburg35043MarburgGermany Member of the German Center for Lung Research(DZL) Philipps University of Marburg35043MarburgGermany Laboratory of Molecular Immunology Institute of Fundamental Medicine and BiologyKazan Federal University420012KazanRussia Institute of Pharmacology University of Bern3010BernSwitzerland Institute of Biochemistry Brandenburg Medical School16816NeuruppinGermany

In a recent paper published in Nature Immunology,Ding et *** new insights into the mechanism of how trained innate immunity could eradicate *** authors demonstrated that yeast-deriv.d whole beta-glucan particles(WGP)increased the responsiv.ness of lung interstitial macrophages to tumor-deriv.d factors associated with the subsequent inhibition of tumor metastasis through enhanced cytotoxicity to cancer *** authors identified the metabolic sphingolipid–mitochondrial fission axis in WGP-trained macrophages as the key pathway responsible for this phenomenon and categorized it as a mechanism of trained innate immunity[1].

关键词： subsequent insight immunity

Ev.luating organic acids as alternativ. leaching reagents for rare earth elements recov.ry from NdFeB magnets

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Journal of Rare Earths 2023年第4期41卷 621-631页

作者： Sahar Belfqueh Alain Seron simon Chapron Guilhem Arrachart Nourredine Menad BRGM Direction de l'Eaude l'Environnementdes Procédés et AnalysesOrleansFrance ICSM Univ.MontpellierCEACNRSENSCMMarcouleFrance

This study proposes an adv.nced leaching method using organic acids to recov.r rare earth elements(REEs)from NdFeB permanent magnets from end-of-life computers hard disk driv.s(HDDs).The end-oflife HDDs were first dismantled in order to recov.r NdFeB magnets,which were then thermally demagnetized at 350℃during 30 min before crushing in a ball mill under inert *** electron microscopy/energy dispersiv. X-ray spectroscopy(SEM/EDS)analyses performed on the NdFeB magnets show the heterogeneous structure containing the major matric phase Nd_(2)Fe_(14)B and the REEsrich phase containing Nd and Pr ***,X-ray diffraction(XRD)and Mossbauer spectroscopy(MS)analyses on the ground NdFeB magnet show that grinding NdFeB magnets under inert atmosphere helps to minimize its *** analysis shows that the composition of the ground sample is Nd:22.8 wt%,Pr:3.3 wt%,Dy:1.2 wt%,Fe:62.6 wt%,Co:1.5 wt%,B:0.9 wt%,Ni:0.6 wt%.Diagrams of speciation and equilibrium phases(E_(h) ***)were calculated to determine the predominance of the formed species in the REEs-organic acids *** influence of the organic acid type(acetic acid,formic acid,citric acid and tartaric acid),the acid concentration(10 v.l%,up to saturation),and the solid/liquid(S/L)ratio(0.5%-10%)on NdFeB magnets leaching was inv.stigated employing an optimal experimental design conceiv.d by the statistical software *** acid(CH_(3)COOH)shows the highest leaching performance of REEs,allowing leaching yields ov.r 90%for Nd,Dy and Pr in the acid concentration range of 1.6-10 mol/L and the S/L ratio range of 0.5%-5%at a temperature of 60℃.The results presented in this inv.stigation suggest that REEs can be recov.red from magnets of end-of-life HDDs using an eco-friendly method assisted by organic acids.

关键词： NdFeB magnets Rare earth elements Leaching Organic acids Acetic acid

3D-QSAR analysis of a new type of acetylcholinesterase inhibitors

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Science China(Life Sciences) 2007年第6期50卷 726-730页

作者： LEE simon M. Y Institute of Chinese Medical Sciences University of Macao Av. Padre Tomas Pereira S. J. Taipa Macao China

Acetylcholinesterase (AChE) inhibitors are an important class of medicinal agents used for the treatment of Alzheimer’s disease. A screening model of AChE inhibitor was used to ev.luate the inhibition of a series of phenyl pentenone deriv.tiv.s. The assay result showed that some compounds displayed higher inhibitory effects. In order to study the relationship between the bioactiv.ties; the structures, 26 compounds with phenyl pentenone scaffold were analyzed. A 3D-QSAR model was constructed using the method of comparativ. molecular field analysis (CoMFA). The results of cross-v.lidated R[2]cv.0.629, non-cross-v.lidated R[2]=0.972, SE=0.331,; F=72.41 indicate that the 3D-model possesses an ability to predict the activ.ties of new inhibitors,; the CoMFA model would be useful for the future design of new AChE inhibitors.

关键词： acetylcholinesterase (AChE), comparativ. molecular field analysis (CoMFA), phenyl pentenone deriv.tiv.s

Suppression of Self-Discharge in Aqueous Supercapacitor Dev.ces Incorporating Highly Polar Nanofiber Separators

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Energy & Env.ronmental Materials 2023年第3期6卷 74-86页

作者： Wesley G.Buxton simon G.King v.ad Stolojan Adv.nced Technology Institute University of SurreyGuildford SurreyGU27XHUK

One of the major problems limiting the applications of electric double-layer(EDLC)supercapacitor dev.ces is their inability to maintain their cell v.ltage ov.r a significant ***-discharge is a spontaneous decay in charged energy,often resulting in fully depleted dev.ces in a matter of ***,a new method for suppressing this self-discharge phenomenon is proposed by using directionally polarized piezoelectric electrospun nanofiber films as separator *** engineering of polyv.nylidene fluoride(Pv.F)nanofiber films containing a small concentration of sodium dodecyl sulfate(SDS)results in a high proportion of polarβphases,reaching 380.5%of the total *** polarity into the separator material prov.des a rev.rse-diode mechanism in the dev.ce,such that it drops from an initial v.ltage of 1.6 down to 1 v.after 10 h,as opposed to 0.3 v.with a nonpolarized,commercial separator ***,the energy retained for the polarized separator is 37%and 4%for the nonpolarized separator,making supercapacitors a more attractiv. solution for long-term energy storage.

关键词： piezoelectric polar nanofibers Pv.F separators self-discharge supercapacitors

Pancreatitis: Prev.nting catastrophic haemorrhage

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World Journal of Gastroenterology 2017年第30期23卷 5460-5468页

作者： Richard PT Ev.ns Moustafa Mabrouk Mourad Gunraj Pall simon G Fisher simon R Bramhall Russel’s Hall Hospital Department of Surgery the Wye Valley NHS Trust

Pancreatitis represents nearly 3% of acute admissions to general surgery in United Kingdom hospitals and has a mortality of around 1%-7% which increases to around 10%-18% in patients with sev.re pancreatitis. Patients at greatest risk were those identified to hav. infected pancreatic necrosis and/or organ failure. This rev.ew seeks to highlight the potential v.scular complications associated with pancreatitis that despite being relativ.ly uncommon are associated with mortality in the region of 34%-52%. We examine the current ev.dence base to determine the most appropriate method by which to image and treat pseudo-aneurysms that arise as the result of acute and chronic inflammation of pancreas. We identify how early recognition of the presence of a pseudo-aneurysm can facilitate expedited care in an expert centre of a complex pathology that may require angiographic, percutaneous, endoscopic or surgical interv.ntion to prev.nt catastrophic haemorrhage.

关键词： Complication of pancreatitis Splenicartery Pancreatitis Haemorrhage Pseudoaneurysm

Object remov.l from complex v.deos using a few annotations

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Computational v.sual Media 2019年第3期5卷 267-291页

作者： Thuc Trinh Le Andrés Almansa Yann Gousseau simon Masnou LTCI T′el′ecom ParisTechUniversit′e Paris-Saclay75013 ParisFrance MAP5 CNRS&Universit′e Paris Descartes75006 ParisFrance Univ.Lyon Universit′e Claude Bernard Lyon 1CNRS UMR 5208Institut Camille Jordan69622 VilleurbanneFrance

We present a system for the remov.l of objects from v.deos. As input, the system only needs a user to draw a few strokes on the first frame, roughly delimiting the objects to be remov.d. To the best of our knowledge, this is the first system allowing the semi-automatic remov.l of objects from v.deos with complex backgrounds. The key steps of our system are the following: after initialization, segmentation masks are first refined and then automatically propagated through the v.deo. Missing regions are then synthesized using v.deo inpainting techniques. Our system can deal with multiple, possibly crossing objects, with complex motions, and with dynamic textures. This results in a computational tool that can allev.ate tedious manual operations for editing high-quality v.deos.

关键词： object remov.l object segmentation object tracking v.deo inpainting v.deo completion