检索结果-南通市图书馆

Photocatalytic perf.rmance of.K2Ti6O13 whiskers to H2 evolution and CO2 photo-reduction

维普期刊数据库评论

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.Energy Chemistry 2019年第10期28卷 18-28页

作者： L. f. Garay-Rodríguez L.m.Torres-martínez E.moctezuma f.cultad de Ingeniería Civil-Departamento de Ecomateriales y Energía Universidad Autónoma de Nuevo LeónAv. Universidad S/N Cd. UniversitariaC. P. 66455 San Nicolás de los GarzaNLMéxico f.cultad de Ciencias Químicas Universidad Autónoma de San Luis PotosíAv. Manuel Nava#6C. P.78290 San Luis PotosíSLPMéxico

K2Ti6O13 whiskers were synthesized by conventional sol-gel method, sono-chemical assisted and microwave assisted sol-gel method in order to obtain catalysts with dif.erent particle sizes and to modif. their optical, textural and electrochemical properties. These modif.cations improved their photocatalytic activity f.r H2 evolution and CO2 photo-reduction. Long K2Ti6O13 whiskers prepared by ultrasound assisted sol-gel method are the most active photocatalysts f.r the hydrogen evolution reaction using pure water as reactant (U-SG, 10,065 μmol g^-1). In contrast, an opposite behavior was observed using a mixture of.ethanol-water, where the highest activity was achieved by the shortest and less crystalline K2Ti6O13 whiskers (C-SG, 3,2871 μmol g^-1). In case of.CO2 photo-reduction, long whiskers that were also prepared by the sono-chemical assisted sol-gel method were the most active to transf.rm CO2 to f.rmaldehyde, methane, methanol and hydrogen. The Ef. value of.this catalyst is located very close to the potential f.r f.rmaldehyde production and f.vors the selectivity to this organic product.

关键词： K2Ti6O13 Sol-gel Whiskers Hydrogen evolution CO2 reduction

Doping Ef.ect of.Poly(vinylidene f.uoride) on Carbon nanof.bers Deduced by Thermoelectric Analysis of.Their melt mixed f.lms

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of.Polymer Science 2024年第11期 1802-1810页

作者： A.J.Paleo V.m.Serrato J.m.mánuel O.Toledano E.mu?oz m.melle-f.anco B.Krause P.P?tschke K.Lozano 2C2T-Centre f.r Textile Science and Technology University of Minho Campus de Azurém f.orida Institute of.Technology The Aerospace Corporation Department of.Condensed matter Physics and Institute of.Research on Electron microscopy and materials(imEYmAT) Faculty of Sciences University of Cádiz CICECO – Aveiro Institute of.materials Department of Chemistry University of Aveiro UnED-Universidad nacional de Educación a Distancia f.cultad de f.sica Pontificia Universidad Católica de Chile Leibniz-Institut f.r Polymerf.rschung Dresden e.V.IPf Department of.mechanical Engineering University of Texas Rio Grande Valley

The ef.ect of.temperature on the electrical conductivity （σ） and Seebeck coef.icient （S） of.n-type vapor grown carbon nanof.bers （Cnf.）and poly（vinylidene f.uoride）(PVDf. melt-mixed with 15 wt%of.those Cnf. is *** 40°C,the Cnf. show stable n-type character (S=-4.8μV·K-1) with anσof.ca.165 S·m-1,while the PVDf.Cnf.composite f.lm shows anσof.ca.9 S·m-1and near-zero S (S=-0.5μV·K-1).This experim.ntal reduction in S is studied by the density f.nctional tight binding （Df.B） method revealing a contact electron transf.r f.om the Cnf. to the PVDf.in the ***,in the temperature range f.om 40°C to 100°C,theσ（T） of.the Cnf. and PVDf.Cnf.f.lm,successf.lly described by the 3D variable range hopping （VRH） model,is explained as consequence of.a thermally activated backscattering *** the contrary,the S（T）f.om 40°C to 100°C of.the PVDf.Cnf.f.lm,which satisf.ctorily matches the model proposed f.r some multi-walled carbon nanotube （mWCnT）doped mats;however,it does not f.llow the increase in S（T） f.und f.r *** these f.ndings are presented with the aim of.discerning the role of.these n-type vapor grown carbon nanof.bers on theσand S of.their melt-mixed polymer composites.

关键词：

multiscale characterization of.nanoparticles in a magnetically assisted f.uidized bed

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Particuology 2020年第4期18卷 64-71页

作者： f.Karimi m.Haghshenasf.rd R.Sotudeh-Gharebagh R.Zarghami n.mostouf. Department of.Chemical Engineering Isfahan University of TechnologyP.O.Box ***IsfahanIran School of.Chemical Engineering College of EngineeringUniversity of TehranP.O.Box 11155/4563TehranIran

Pressure f.uctuations of.a f.uidized bed of.nanoparticles were measured during the f.uidization of.nanoparticles with and without a magnetic f.eld at a f.equency of.50 *** quantif.cation analysis(RQA)and wavelet transf.rm were used to determine the f.equency range of.various f.ow structures in the bed at three *** f.equency ranges of.the macro-,meso-,and micro-structures were determined to be 0-49Hz,49-781 Hz,and 781+Hz,*** of.the determinisms of.the sub-signals with and without the external f.eld revealed that in the presence the f.eld,breakage of.larger agglomerates occurs f.ster than re-agglomeration of.small agglomerates into larger *** power spectral density f.nction of.the pressure f.uctuations indicated that with an external magnetic f.eld,the power and the f.equency range of.the pressure signal of.macro-structures do not change ***,the power of.the meso-structure signal increases and its f.equency range is widened toward higher f.equencies,conf.rming that the number of.small bubbles and agglomerates increase in the *** addition,the energy of.signal analysis indicated that the external f.eld signif.cantly increases the share of.meso-structures in the bed,conf.rming the RQA results.

关键词： nanoparticles f.uidized bed magnetic f.eld Pressure f.uctuations Recurrence quantif.cation analysis Wavelet transf.rm

Oxidation and Coatings f.r Power Generation： new Super Ultra Critical Steam Turbines

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国腐蚀与防护学报 2009年第4期29卷 318-319页

作者： f. J. PEREZ Grupo de Investigacion de Ingenieria de Superf.cies y materiales nanoestructurados U. C. m. n°910627 f.cultad de Ciencias Quimicas Universidad Complutense de madrid. 28040 madrid Spain

The steels with chromium contents between 9%and 12%wt are used f.r power plants with advanced steam oxidation *** present good creep properties as 9%Cr steels and good oxidation resistance,at the temperatures range between 500℃～600℃.In the last years numerous investigation in development of.coatings has been realized with the aim the protected them against the oxidation in order to allow operation of.steam turbines at 650℃.In this study,Al-Hf.protective coatings were deposited by CVD-f.R on f.rritic steel HCm-12A f.llowed by a dif.usion heat treatment,have shown to be protective at 650℃under steam f.r at least 3000 hours of.laboratory steam exposure under atmospheric *** and composition of.coatings were characterized by dif.erent techniques, such as scanning electron microscopy(SEm),electron probe microanalysis,and X-ray dif.raction(XRD). On the other hand,volatile species by mass spectrometry(mS) and thermogravimetric measurements (TG) during the initial stages oxidation of.the P92 f.rritic steel without and of.Al and Al/Si coating by chemical vapour deposition in f.uidized bed reactors(CVD-f.R) at 650℃in Ar+20%H_2O f.r 150 h were *** order to go f.rward to coatings design the Thermocalc code is used as base f.r the mSdata. TG-mS experim.nts were conducted in a closed steam loop in order to obtain inf.rmation about the oxyhydroxides f.rmation as reaction between coatings and *** those results the role of.the dif.erent coating element could be established and optimized f.r the coating *** oxidation mechanism based on the TG-mS results is *** morphology/composition and structure of.the oxidized samples were also studied using SEm/EDS and XRD techniques.

关键词：氧化金属腐蚀防护

Relationship between Obsessive-Compulsive Symptoms and Anxiety Levels during the COVID-19 Pandemic in Healthcare Prof.ssionals ***-Healthcare Prof.ssionals

在线全文

学校读者我要写书评

暂无评论

International Journal of.mental Health Promotion 2022年第3期24卷 399-413页

作者： f.ruk Kurhan Gülsüm Zuhal Kamış Emine f.sun AkyüzÇim Abdullah Atli Dilem Dinc Department of.Psychiatry f.culty of.medicine Yuzuncu Yil UniversityVanTurkey Department of.Psychiatry Bilkent City HospitalAnkaraTurkey Department of.Psychiatry Florence Nightingale HospitalİstanbulTurkey Department of.Psychiatry Medical School of Dicle UniversityDiyarbakirTurkey Department of.Psychology Kahramanmaras Istiklal UniversityKahramanmarasTurkey

The present study investigated the ef.ect of.the COVID-19 pandemic on anxiety levels,contamination and responsibility/control obsessions and associated OC behaviors in healthcare versus non-healthcare *** study also aimed to examine the relationship between anxiety levels and obsessive-compulsive(OC)symptom levels,gender,age,educational level,and personal and f.mily history of.chronic *** 664 participants included 395(59.5%)men and 269(40.5%)women and comprised 180(27.1%)healthcare prof.ssionals and 484(72.9%)non-healthcare *** survey included three data collection tools:(i)Sociodemographic data f.rm,(ii)Beck Anxiety Inventory(BAI),and(iii)the Dim.nsional Obsessive-Compulsive Scale Abriged(DOCS-A)pre-and post-pandemic *** BAI scores established a moderate positive correlation with post-pandemic DOCS-A total scores and a weak positive correlation with pre-pandemic DOCS-A total scores(pf.r both).Pre-and post-pandemic DOCS-A total and subdim.nsion scores were signif.cantly higher in women than in men(pnts with a personal history of.chronic diseases had higher BAI and DOCS-A scores compared to participants with no such history(pnd pndicated a signif.cant increase in OC symptoms during the pandemic period compared to the pre-pandemic period and a moderate correlation between the anxiety levels and OC symptom *** was also revealed that f.male gender and personal or f.mily history of.chronic diseases posed a higher risk f.r the increase in anxiety and OC symptoms and healthcare prof.ssionals had a higher risk of.developing anxiety symptoms compared to non-healthcare prof.ssionals.

关键词： Pandemic healthcare prof.ssionals non-healthcare prof.ssionals obsessive behavior

An Expansion Theorem f.r an Eigenvalue Problem of.an Arbitrary multiply Connected Domain with an Eigenparameter in a General Type of.Boundary Conditions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta mathematica Sinica,English Series 1995年第4期11卷 399-407页

作者： E. m. E. Zayed S. f. m. Ibrahim mathematics Department f.culty of.Science Zagazig University Zagazig Egypt mathematics Department f.culty of.Science Ain Shams University Heliopolis Cairo Egypt

The object of.this paper is to establish an expansion theorem f.r a regular right- def.nite eigenvalue problem with an eigenvalue parameter λ which is contained in the Schrodinger partial dif.erential,equation and in a general type of.boundary conditions on the boundary of.an arbitrary multiply connected bounded domain in R^n(n≥2).We associate with this problem an essentially self.adjoint operator in a suitably def.ned Hilbert space and then we develop an associated eigenf.nction expansion theorem.

关键词： Eigenvalue problem multiply connected domain Eigenf.nction expansion

The ef.icacy of.vitamin E in preventing arthrof.brosis af.er joint replacement

在线全文

学校读者我要写书评

暂无评论

Animal models and Experim.ntal medicine 2024年第2期7卷 145-155页

作者： Yingf.ng f.n Jean Yuh Sashank Lekkala mehmet D.Asik Andrew Thomson madeline mcCanne mark A.Randolph Antonia f.Chen Ebru Oral Harris Orthopaedic Laboratory Department of Orthopaedic SurgeryMassachusetts General HospitalBostonMassachusettsUSA Department of.Orthopaedic Surgery Harvard Medical SchoolBostonMassachusettsUSA Department of.Surgery Harvard Medical SchoolBostonMassachusettsUSA Department of.Orthopaedic Surgery Brigham and Women's HospitalBostonMassachusettsUSA

Background:Arthrof.brosis is a joint disorder characterized by excessive scar f.rmation in the joint *** E is an antioxidant with potential anti-f.broblastic *** aim of.this study was to establish an arthrof.brosis rat model af.er joint replacement and assess the ef.ects of.vitamin E supplementation on joint ***:We simulated knee replacement in 16 male Sprague–Dawley *** immobilized the surgical leg with a suture in f.ll *** control groups were killed at 2 and 12 weeks(n=5 per group),and the test group was supplemented daily with vitamin E(0.2 mg/mL)in their drinking water f.r 12 weeks(n=6).We perf.rmed histological staining to investigate the presence and severity of.*** staining andα2-macroglobulin(α2m)enzyme-linked immunosorbent assay(ELISA)were used to assess local and systemic *** weight bearing(total internal ref.ection)and range of.motion(ROm)were collected f.r f.nctional ***:The ROm and weight-bearing symmetry decreased af.er the procedure and recovered slowly with still signif.cant def.cit at the end of.the study f.r both *** analysis conf.rmed f.brosis in both lateral and posterior periarticular *** E supplementation showed a moderate anti-inf.ammatory ef.ect on the local and systemic *** vitamin E group exhibited signif.cant improvement in ROm and weight-bearing symmetry at day 84 compared to the control ***:This model is viable f.r simulating arthrof.brosis af.er joint *** E may benef.t postsurgical arthrof.brosis,and f.rther studies are needed f.r dosing requirements.

关键词： arthrof.brosis range of.motion total knee arthroplasty vitamin E

Highly electroactive n–f. hydrothermal carbons and carbon nanotubes f.r the oxygen reduction reaction

在线全文

学校读者我要写书评

暂无评论

Journal of.Energy Chemistry 2020年第11期29卷 260-270页

作者： R.G.morais n.Rey-Raap J.L.f.gueiredo m.f.R.Pereira Associate Laboratory LSRE-LCm Departamento de Engenharia QuimicaFaculdade de EngenhariaUniversidade do PortoR.Dr.Roberto Frias s/n4200-465PortoPortugal

Glucose-derived carbons were prepared by hydrothermal carbonization of.glucose f.llowed by carbonization or activation to obtain carbon materials with dif.erent microporosities. These microporous carbons and carbon nanotubes(CnTs) were f.nctionalized with melamine and/or iron(Ⅱ) phthalocyanine(f.Pc)f.llowing three dif.erent methodologies:(i) f.nctionalization with melamine via thermal treatment,(ii)incorporation of.the lowest amount of.f.Pc reported in the literature via incipient wetness impregnation f.llowed by thermal treatment and(iii) f.nctionalization with melamine f.llowed by f. Pc *** chemical and textural characterization of.the prepared materials and their electrochemical assessment allowed to understand the role of.microporosity in the incorporation of.f.Pc and its ef.ect on the oxygen reduction reaction(ORR). It was observed that f.Pc was pref.rentially incorporated inside the porous structure, especially in samples with more developed microporosity. However, f.nctionalization with melamine modif.ed the textural properties and the surf.ce chemistry, f.voring the incorporation of.f.Pc on the surf.ce. Regarding the electrochemical perf.rmance, the presence of.f.Pc greatly enhanced the electroactivity of.the microporous catalysts. An onset potential of.0.88 V and a f.ur-electron pathway were obtained f.r glucose-derived carbons, whereas the limiting current densities and kinetic current densities rose by 126% and 222%, respectively, in comparison to the base sample. notwithstanding, the highest electrochemical activity was observed f.r the sample prepared with CnTs, due to the synergy between the active metal centers and their highly graphitic carbon structure. The electrochemical parameters of.CnTf.P csurpass the commercial Pt/C. The half.wave potential is 40 mV higher, the limiting current density increases by 17%, and a negligible production of.by-products(< 1%) was observed.

关键词： Iron(Ⅱ)phthalocyanine Hydrothermal carbons Carbon nanotubes Oxygen reduction reaction Electrocatalysis

Corrosion behaviour of.PEEK or β-TCP-impregnated Ti6Al4V SLm structures targeting biomedical applications

在线全文

学校读者我要写书评

暂无评论

Transactions of.nonf.rrous metals Society of.China 2019年第12期29卷 2523-2533页

作者： m.m.COSTA T.A.DAnTAS f.BARTOLOmEU n.ALVES f.S.SILVA G.mIRAnDA f.TOPTAn Center f.r micro Electro mechanical Systems(CmEmS) University of Minho(UMinho)4800-058 GuimarãesPortugal mIT Portugal Program School of EngineeringUniversity of MinhoGuimarãesPortugal Centre f.r Rapid and Sustainable Product Development Polytechnic Institute of.Leiria Rua General Norton de MatosApartado 4133LeiriaPortugal IBTn/Br–Brazilian Branch of.the Institute of.Biomaterials Tribocorrosion and NanomedicineUNESPCampus de BauruAv.Eng.Luiz Edmundo Carrijo Coube14-0117033-360BauruSPBrazil

Ti6Al4V cellular structures were produced by selective laser melting(SLm)and then f.lled either with beta-tricalcium phosphate(β-TCP)or PEEK(poly-ether-ether-ketone)through powder metallurgy techniques,to improve osteoconductivity and wear *** corrosion behavior of.these structures was explored considering its importance f.r the long-term perf.rmance of.*** revealed that the incorporation of.open cellular pores induced higher electrochemical kinetics when being compared with dense *** impregnation of.-TCP and PEEK led to the creation of.voids or gaps between the metallic matrix and the impregnated material which also inf.uenced the corrosion behavior of.the cellular structures.

关键词： Ti6Al4V cellular structures corrosion multimaterial design poly-ether-ether-ketone(PEEK) beta-tricalcium phosphate(β-TCP)