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Electrochemical top-down synthesis of C-supported Pt nanoparticles with controllable shape and size:mechanistic insights and application

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Nano Research 2021年第8期14卷 2762-2769页

作者： Batyr Garlyyev Sebastian Watzele Johannes Fichtner jan michalicka Alexander Schokel Anatoliy Senyshyn Andrea Perego Dingjie Pan Hany A.El-Sayed jan m.macak Plamen Atanassov Iryna V.Zenyuk Aliaksandr S.Bandarenka Physics of Energy Conversion and Storage Technical University of MunichJames Franck Strafle 185748 Garching Germany Central European Institute of Technology Brno University of TechnologyPurkynova 12361200 BrnoCzech Republic Deutsches Elektronen Synchrotron(DESY) Notkestr.8522607HamburgGermany Heinz maier-Leibnitz-Zentrum(mLZ) Technische Universitat MiinchenLichtenbergstr.185748 Garching Germany Department of Chemical Engineering National Fuel Cell Research Center University of CaliforniaIrvine92697-2580 CaliforniaUSA Department of material Science and Engineering University of CaliforniaIrvine92697-2580 CaliforniaUSA Chair of Technical Electrochemistry Technical University of MunichLichtenbergstrafie 485748 Garching Germany

In this work,we demonstrate the power of a simple top-down electrochemical erosion approach to obtain Pt nanoparticle with controlled shapes and sizes(in the range from-2 to-10 nm).Carbon supported nanoparticles with narrow size distributions have been synthesized by applying an alternating voltage to macroscopic bulk platinum structures,such as disks or *** using any surfactants,the size and shape of the particles can be changed by adjusting simple parameters such as the applied potential,frequency and electrolyte *** instance,application of a sinusoidal AC voltage with lower frequencies results in cubic nanoparticles;whereas higher frequencies lead to predominantly spherical *** the other hand,the amplitude of the,sinusoidal signal was found to affect the particle size;the lower the amplitude of the applied AC signal,the smaller the resulting particle ***/C catalysts prepared by this approach showed 0.76 A/mg mass activity towards the oxygen reduction reaction which is-2 times higher than the state-of-the-art commercial Pt/C catalyst(0.42 A/mg)from *** addition to this,we discussed the mechanistic insights about the nanoparticle formation pathways.

关键词： electrochemical synthesis platinum nanoparticles oxygen reduction reaction

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A LIOUVILLE THEOREm FOR STATIONARY INCOmPRESSIBLE FLUIDS OF VON mISES TYPE

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Acta mathematica Scientia 2019年第1期39卷 1-10页

作者： martin FUCHS jan müLLER Fachbereich 6.1 mathematik Universit?t des Saarlandes

We consider entire solutions u of the equations describing the stationary flow of a generalized Newtonian fluid in 2 D concentrating on the question, if a Liouville-type result holds in the sense that the boundedness of u implies its constancy. A positive answer is true for p-fluids in the case p > 1(including the classical Navier-Stokes system for the choice p = 2), and recently we established this Liouville property for the Prandtl-Eyring fluid model,for which the dissipative potential has nearly linear growth. Here we finally discuss the case of perfectly plastic fluids whose flow is governed by a von mises-type stress-strain relation formally corresponding to the case p = 1. It turns out that, for dissipative potentials of linear growth, the condition of μ-ellipticity with exponent μ m.

关键词： generalized Newtonian fluids perfectly plastic fluids von mises flow Liouville theorem

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BOUNDARY PROCEDURES FOR THE TImE-DEPENDENT BURGERS' EQUATION UNDER UNCERTAINTY

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Acta mathematica Scientia 2010年第2期30卷 539-550页

作者： Per Pettersson jan Nordstrm Gianluca Iaccarino mechanical Engineering and Institute for Computational mathematical Engineering Stanford University Division of Scientific Computing Department of Information TechnologyUppsala University School of mechanical Industrial and Aeronautical EngineeringUniversity of the Witvatersrand Department of Aeronautics and Systems Integration FOIThe Swedish Defense Research Agency

The Burgers＇ equation with uncertain initial and boundary conditions is approximated using a Polynomial Chaos Expansion （PCE） approach where the solution is represented as a series of stochastic, orthogonal polynomials. The resulting truncated PCE system is solved using a novel numerical discretization method based on spatial derivative operators satisfying the summation by parts property and weak boundary conditions to ensure stability. The resulting PCE solution yields an accurate quantitative description of the stochastic evolution of the system, provided that appropriate boundary conditions are available. The specification of the boundary data is shown to influence the solution; we will discuss the problematic implications of the lack of precisely characterized boundary data and possible ways of imposing stable and accurate boundary conditions.

关键词： stochastic Burgers' equation uncertainty quantification polynomial chaos

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A new design approach for the established flow region of vertical,dilute-phase pneumatic conveyors

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Particuology 2022年第7期20卷 10-20页

作者： John m.Wheeldon jan Baeyens Shuo Li Yimin Deng European Powder and Process Technology Longfellow DriveKetteringUnited Kingdom KU Leuven Department of Chemical EngineeringProcess and Environmental Technology LabJ.De Nayerlaan 52860 Sint-Katelijne-WaverBelgium Beijing University of Chemical Technology Beijing Advanced Centre of Smart Matter Science and EngineeringBeijingChina

An analysis has been completed for a comprehensive set of vertical,dilute-phase pneumatic conveying pressure drop data from an investigation by *** data were collected in the established flow region for eight different materials conveyed in 0.05-,0.10-,0.20-m internal diameter,20-m tall steel *** velocities derived from the pressure drop data were used to develop an equation of motion that includes terms for pipe diameter,terminal velocity,coefficient of restitution,and particle *** best data fit was achieved using the actual gas density and the actual gas velocity adjusted for *** the terminal velocity for voidage,an approach recommended by many investigators,did not improve the fit for reasons identified by the present *** the equation of motion,particle velocities were predicted and used to calculate total pressure drops that are within±15%of the measured *** calculated values also produce the characteristic trough-shaped total pressure drop curves allowing the minimum pressure drop gas velocity to be determined without recourse to a separate correlation.A comparison with other studies using shorter risers indicates that data from these studies likely include acceleration effects.A separate study will investigate this observation further.

关键词： Dilute-phase Vertical Pneumatic conveying Design equations Pressure drops

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Investigating the use cases of a novel heat battery in Dutch residential buildings

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Building Simulation 2023年第9期16卷 1675-1689页

作者： Shuwei Wang Pieter-jan Hoes jan L.m.Hensen Olaf C.G.Adan Pim A.J.Donkers Department of the Built Environment Eindhoven University of TechnologyEindhovenP.O.Box 5135600 MB Eindhoventhe Netherlands Department of Applied Physics Eindhoven University of TechnologyEindhovenP.O.Box 5135600 MB Eindhoventhe Netherlands TNO materials Solutions P.O.Box 62355600 HE Eindhoventhe Netherlands Cellcius BV Horsten 15612 AXEindhoventhe Netherlands

Recent advances in thermochemical storage technology have introduced a novel closed-loop thermal energy storage(TES)system,known as the heat battery(HB),which is believed to have great potential for aiding the energy transition in the built environment because of its higher energy density and neglectable storage loss compared to conventional TES *** order to investigate the potential use cases of the HB and provide practical feedback for its further development,this research employs a simulation-based approach to analyze its influence on building performance in various use cases within Dutch residential *** including the homeowner,distribution system operator,and district heating system operator are identified,and a preliminary list of use cases is defined based on relevant literature and input from the HB *** simulation approach is conducted to predict key performance indicators for each *** Kruskal-Wallis test was employed to sort and scrutinize the simulation outcomes and discern the significance of each use case *** findings demonstrated that the HB holds the potential to diminish both the operational energy cost by up to 30%for the homeowners and the peak heating load transmitted from the building to the district heating system.

关键词： thermochemical storage building performance simulation use case solar energy demand-side management

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DESIGN FOR AVAILABILITY:A HOLISTIC APPROACH TO CREATE VALUE FOR mANUFACTURERS AND CUSTOmERS OF CAPITAL GOODS

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Journal of Systems Science and Systems Engineering 2012年第4期21卷 403-421页

作者： Lydie P.m.SmETS Geert-jan van HOUTUm Fred LANGERAK School of Industrial & Systems Engineering Eindhoven University of Technologythe Netherlands

This research introduces a holistic framework called Design for Availablhty that uses me principles of Lean Sigma and Design for X to cost-effectively optimize the availability of capital goods （i.e., technical systems used in the production of end-products or -services such as medical systems, airplanes, and manufacturing equipment） throughout their entire lifetime. manufacturers require such a framework because users of capital goods increasingly insist on high system availability levels against reduced lifetime costs. The Design for Availability framework allows manufacturers to determine the current status of system availability and associated lifetime costs, and to identify opportunities to create additional value for themselves and their customers. A case study at a global manufacturer of capital goods in the food processing industry illustrates how the framework can be used in practice and to what extent the manufacturer and customers may profit from applying Design for Availability.

关键词： Design for X system availability mTTR mTTF mTTS lifecycle costs capital goods

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Comparative Study of Plasma Parameters in magnetic Pole Enhanced Inductively Coupled Argon Plasmas

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Plasma Science and Technology 2013年第4期15卷 329-334页

作者： F.jan A.W. KHAN A.SAEED m.ZAKAULLAH Department of Physics Quaid-i-Azam University Department of Physics Gomal University

Langmuir probe measurements of radio frequency （RF） magnetic pole enhanced inductively coupled （maPE-ICP） argon plasma were accomplished to obtain the electron number densities and electron temperatures. The measurements were carried out with a fixed RF frequency of 13.56 mHz in a pressure range of 7.5 mTorr to 75 mTorr at an applied RF power of 10 W and 100 W. These results are compared with a global （volume average） model. The results show good agreement between theoretical and experimental measurements. The electron number density shows an increasing trend with both RF power and pressure while the electron temperature shows decreasing trend as the pressure increases. The difference in the plasma potentim and floating potential as a function of electron temperature measured from the electrical probe and that obtained theoretically shows a linear relation with a small difference in the coefficient of proportionality. The intensity of the emission line at 750.4 nm due to 2pl → 1s2 （Paschen＇s notation） transition closely follows the variation of ne with RF power and filling gas pressure. measured electron energy probability function （EEPF） shows that electron occupation changes mostly in the high-energy tail, which highlights close similarity of 750.4 nm argon line to he.

关键词： maPE-ICP Langmuir probe global model

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Influence of nitrogen and sulfur fertilization on quality of canola(Brassica napus L.) under rainfed conditions

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2007年第10期8卷 731-737页

作者： AHmAD G. jan A. ARIF m. jan m.T. KHATTAK R.A. Cereal Crops Research Institute (CCRI) Pirsabak North West Frontier Province (NWFP) 25000 Pakistan Department of Agronomy Agricultural University Peshawar North West Frontier Province (NWFP) 25000 Pakistan Dean Faculty of Crop Production Sciences Agricultural University Peshawar North West Frontier Province (NWFP) 25000 Pakistan

Field experiments were conducted at Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan, during winter 2003～2004; 2004～2005 to evaluate the effect of nitrogen; sulfur levels; methods of nitrogen application on canola (Brassica napus L. cv. Bulbul-98) under rainfed conditions. Four levels of S (0, 10, 20,; 30 kg/ha); three levels of N (40, 60,; 80 kg/ha); a control treatment with both nutrients at zero level were included in the experiments. Sulfur levels were applied at sowing while N levels were applied by three methods (100% soil application, 90% soil+10% foliar application,; 80% soil +20% foliar application). The experiments were laid out in randomized complete block (RCB) design having four replications. Oil content increased significantly up to 20 kg S/ha but further increase in S level did not enhance oil content. Glucosinolate content increased from 13.6 to 24.6 μmol/g as S rate was increased from 0 to 30 kg/ha. Protein content increased from 22.4% to 23.2% as S rate was increased from 0 to 20 kg/ha. Oil content responded negatively to the increasing N levels. The highest N level resulted in the highest values for protein (23.5%); glucosinolate (19.9 μmol/g) contents. methods of N application had no significant impact on any parameters under study.

关键词： Canola Nitrogen (N) Sulfur (S) methods of N application Quality

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Removal of Rhodamine B from aqueous solutions and wastewater by walnut shells： kinetics, equilibrium and thermodynamics studies

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Frontiers of Chemical Science and Engineering 2013年第4期7卷 428-436页

作者： Jasmin Shah m. Rasul jan Attaul Haq Younas Khan Institute of Chemical Sciences University of Peshawar Peshawar Pakistan

An adsorption study ofRhodamine B （RB） dye from aqueous solutions was carried out using walnut shells pretreated by different methods. In addition to the effects of the pretreatment, the effects of various parameters like pH, adsorbent dose, contact time, initial dye concentration and temperature on the adsorption of RB was studied. The adsorption process was highly pH dependent and a maximum adsorption was achieved at pH 3.0. The best fit for the rates of dye adsorption was a pseudo-second- order kinetic model with good correlation coefficients （R2〉 0.99）. Langmuir isotherms were used to determine that the maximum loading capacity of the different walnut shells and the RB capacities ranged from 1.451-2.292 mg ~ gl. The dye adsorption was also evaluated thermodyna- mically. Positive standard enthalpy （m-P） values were obtained indicating that the RB adsorption process is endothermic as well as AG~ and AS~ values showed that adsorption process is spontaneous with an increased randomness at the solid-liquid interface~ Desorption studies were carried out to explore the feasibility of regenerating the used walnut shells and it was found that 97~71%-99.17% of the retained RB was recovered with 0.1 mol＂ L 1 NaOH solution. The walnut shells were also successfully used to remove RB from industrial effluents.

关键词： Rhodamine B walnut shell adsorption,kinetics isotherms regeneration

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Timings of early crustal activity in southern highlands of mars:Periods of crustal stretching and shortening

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Geoscience Frontiers 2019年第3期10卷 1029-1037页

作者： Trishit Ruj Goro Komatsu jan Hendrik Pasckert James m.Dohm International Research School of Planetary Sciences Università d'Annunzio Department of Earth and Planetary Science School of Science University of Tokyo Institut für Planetologie Westf?lische Wilhelms-Universit?t Foundation for Advancement of International Science

Extensional and compressional structures are globally abundant on mars. Distribution of these structures and their ages constrain the crustal stress state and tectonic evolution of the planet. Here in this paper, we report on our investigation over the distribution of the tectonic structures and timings of the associated stress fields from the Noachis-Sabaea region. Thereafter, we hypothesize possible origins in relation to the internal/external processes through detailed morphostructural mapping. In doing so, we have extracted the absolute model ages of these linear tectonic structures using crater size-frequency distribution measurements, buffered crater counting in particular. The estimated ages indicate that the tectonic structures are younger than the mega impacts events(especially Hellas) and instead they reveal two dominant phases of interior dynamics prevailing on the southern highlands, firstly the extensional phase terminating around3.8 Ga forming grabens and then compressional phase around 3.5-3.6 Ga producing wrinkle ridges and lobate scarps. These derived absolute model ages of the grabens exhibit the age ca. 100 ma younger than the previously documented end of the global extensional phase. The following compressional activity corresponds to the peak of global contraction period in Early Hesperian. Therefore, we conclude that the planet wide heat loss mechanism, involving crustal stretching coupled with gravitationally driven relaxation(i.e.,lithospheric mobility) resulted in the extensional structures around Late Noachian(around 3.8 Ga). Lately cooling related global contraction generated compressional stress ensuing shortening of the upper crust of the southern highlands at the Early Hesperian period(around 3.5-3.6 Ga).

关键词： martian dynamics Southern highlands Extensional tectonics Compressional tectonics Age of structures Buffer crater counting

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