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Metal Dusting-Mechanisms and Preventions

中国腐蚀与防护学报 2009年第4期29卷 262-276页

作者： j. Q. ZHANG D. j. YOUNG School of Materials Science and Engineering University of New South Wales Sydney NSW 2052 Australia

Metal dusting attacks iron,low and high alloy steels and nickel-or cobalt-base alloys by disintegrating bulk metals and alloys into metal particles in a coke *** occurs in strongly carburising gas atmospheres(carbon activity a_C>1) at elevated temperatures(400℃～1000℃).This phenomenon has been studied for decades,but the detailed mechanism is still not well *** methods of protection against metal dusting are either directed to the process conditions-temperature and gas composition-or to the development of a dense adherent oxide layer on the surface of the alloy by selective ***,metal dusting still occurs by carbon dissolving in the base metal via defects in the oxide *** research work at UNSW is aimed at determining the detailed mechanism of metal dusting of both ferritic and austenitic alloys,in particular the microprocesses of graphite deposition,nanoparticle formation and underlying metal *** work was carried out using surface observation,crosssection analysis by focused ion beam and electron microscopic examination of coke deposits at different stages of the *** was found that surface orientation affected carbon deposition and metal dusting at the initial stage of the *** dusting occurred only when graphite grew into the metal interior where the volume expansion is responsible for metal disintegration and *** was also found that the metal dusting process could be significantly changed by alterations in alloy *** was found to affect the iron dusting process by destabilising Fe_3C but increasing the rate of carbon deposition and dusting,which questions the role of cementite in ferritic alloy *** adding copper to iron did not change the carburisation kinetics,cementite formation and coke morphology,copper alloying reduced nickel and nickel-base alloy dusting rates *** of these fundamental results to the dusting behaviour of engineering al

关键词：金属腐蚀氧化防护机械装置

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Small extrachromosomal circular DNA in amyotrophic lateral sclerosis matter

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Neural Regeneration Research 2025年第5期20卷 1411-1413页

作者： Marcos j.Arauzo-Bravo Daniela Gerovska Matthias Schwab Alexandra Kretz Computational Biology and Systems Biomedicine Biodonostia Health Research InstituteSan SebastianSpain Basque Foundation for Science IKERBASQUEBilbaoSpainMax Planck Institute for Molecular BiomedicineComputational Biology and Bioinformatics GroupMünsterNorth Rhine-WestphaliaGermany Department of Cell Biology and Histology Faculty of Medicine and NursingUniversity of Basque Country(UPV/EHU)LeioaSpain Department of Neurology Jena University HospitalJenaThuringiaGermany

Comprehensive studies identify motor neuron spectrum disorders including amyotrophic lateral sclerosis(ALS)as globally rising fatal disorders with the highest prevalence in aging populations,influenced by ethnicity and ancestry(GBD 2016 Motor Neuron Disease Colla borators,2018).While~10% of diagnoses involve a family history(fALS),most cases are considered sporadic(sALS).However,population-based studies suggest that even cases without a common index mutation impart heritability(Ryan et al.,2019),indicating a crucial role of rare and as yet unknown genetic denominators.

关键词： amyotrophic sclerosis

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Stochastic SIS metapopulation models for the spread of disease among species in a fragmented landscape

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International j.urnal of Biomathematics 2016年第4期9卷 97-119页

作者： Amy j. Ekanayake Department of Mathematics Western Illinois University 1 University Circle Maeomb Illinois 61455 USA

Two stochastic models are derived for a susceptible-infectious-susceptible epidemic spreading through a metapopulation： a continuous time Markov chain （CTMC） model and an It6 stochastic differential equation （SDE） model. The stochastic models are numerically compared. Close agreement suggests that computationally intense CTMC simulations can be approximated by simpler SDE simulations. Differential equations for the moments of the SDE probability distribution are also derived, the steady states are solved numerically using a moment closure technique, and these results are compared to simulations. The moment closure technique only coarsely approximates simulation results. The effect of model parameters on stability of the disease-free equilibrium is also numerically investigated.

关键词： Epidemic metapopulation Ito stochastic differential equation Markov chain moment closure.

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A chaotic neural network mimicking an olfactory system and its application on image recognition

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j.urnal of Bionic Engineering 2004年第3期1卷 191-198页

作者： Walter j. Freeman Department of Molecular & Cell Biology UCB LSA 142 Berkeley CA 94720-3200 USA

Based on the research of a biological olfactory system, a novel chaotic neural network model - K set model has been es- tablished. This chaotic neural network not only simulates the real brain activity of an olfactory system, but also presents a novel chaotic concept for signal processing and pattern recognition. The characteristics of the K set models are investigated and show that a KIII model can be used for image pattern classification.

关键词： olfactory system pattern recognition neural networks image classification

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Chromate and selenate hydrocalumite solid solutions and their applications in waste treatment

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Science China(Life Sciences) 2005年第z1期48卷 165-173页

作者： Eric j. Reardon Department of Earth Sciences University of Waterloo Waterloo Ontario Canada N2L 3G1

Hydrocalumite, a calcium aluminate hydrate phase, consists of positively-charged structure units, and is therefore an ideal candidate for accommodating anionic contaminants. In this study, a series of batch experiments was carried out to examine the uptake of chromate and selenate by hydrocalumite. To determine the uptake capacity and long-term stability, hydrocalumite solid solutions between chromate/selenate and hydroxyl were synthesized over a reaction time of more than one year. At a ratio of water to initial solids added (CaAl2O4+CaO) of 75: 1, the maximum uptake capacities were over 77 and 114 g/kg for Cr and Se, *** values are very close to the theoretical uptake capacities of chromate and selenate hydrocalumite end-members (81 and 118 g/kg, respectively). The oxyanion removal efficiency from solution was above 95%. Due to the high uptake capacity and anion removal efficiency of hydrocalumites, their application in wastewater treatment is promising. Hydrocalumites are also important hydration products of cementitious materials and the long-term stability of these phases is of significance for application in solidification/stabilization technology.

关键词： chromate, selenate, hydrocalumite, uptake capacity, stability.

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Does disruptive camouflage conceal edges and features？

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Current Zoology 2015年第4期61卷 708-717页

作者： Richard j. WEBSTER Department of Biology Carleton University Ottawa K1S 5B6 Canada

Camouflage is ubiquitous in the natural world and benefits both predators and prey. Amongst the range of conceal- ment strategies, disruptive coloration is thought to visually fragment an animal＇s＇ outline, thereby reducing its rate of discovery. Here, I propose two non-mutually exclusive hypotheses for how disruptive camouflage functions, and describe the visual me- chanisms that might underlie them. （1） The local edge disruption hypothesis states that camouflage is achieved by breaking up edge information. （2） The global feature disruption hypothesis states camouflage is achieved by breaking up the characteristic features of an animal （e.g., overall shape or facial features）. Research clearly shows that putatively disruptive edge markings do increase concealment; however, few tests have been undertaken to determine whether this survival advantage is attributable to the distortion of features, so the global feature disruption hypothesis is under studied. In this review the evidence for global feature disruption is evaluated. Further, I address if obj.ct recognition processing provides a feasible mechanism for animals＇ features to influence concealment. This review concludes that additional studies are needed to test if disruptive camouflage operates through the global feature disruption and proposes future research directions [Current Zoology 61 （4）： 708-717, 2015].

关键词： Antipredator Background matching Contour Crypsis Camouflage Disruptive coloration Edge detection Obj.ctrecognition

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Throughput maximization in UWB-based ad-hoc networks

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Science China(Information Sciences) 2010年第12期53卷 2538-2547页

作者： HAAS Zygmunt j. School of Electrical and Computer Engineering Cornell University

In this paper,we study the problem of radio resource allocation,both transmission rates and transmission powers,so as to maximize the throughput of UWB wireless ad-hoc *** analysis is based on the packet-success function(PSF),which is defined as the probability of a data packet being successfully received as a function of the receiver’s signal-to-interference-and-noise-ratio(SINR).We find an optimal link transmission rate,which maximizes the link’s throughput and is dependent on the all active links transmission *** each link transmission rate is adapted to this optimal link transmission rate,then,with single-link operation(i.e.,no other interference sources are present),the link’s throughput is directly proportional to the transmitter’s power and increases indefinitely with increasing transmission ***,with multiplelinks operation and interference each other,as each link transmitting power increases,so does the interference level,and the total network throughput approaches a constant other than ***,for sufficiently small transmission power,the total network throughput of the multiple-links case exceeds the throughput of the single-link case,but the reverse happens for high *** addition,this paper reveals that,as the number of concurrently transmitting links increases,regardless of the power level,the maximal total network throughput approaches a constant,with each link’s throughput approaching *** maximize the network throughput,for the case of small maximal transmission power with weak interference levels,the optimal transmission scheduling allocates simultaneous transmissions of multiple links,but for the case of large maximal transmission power with strong interference levels,the optimal policy assigns separate time for transmission on each *** breakpoint of when to use one link or multiple links is termed the critical *** an example of the analytical calculation of the critical link’s power,we present here so

关键词： UWB impulse radio ad-hoc networks throughput rate power resource allocation

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Numerical Analysis of Unsteady Natural Convection Flow and Heat Transfer in the Existence of Lorentz Force in Suddenly Expanded Cavity Using OpenFOAM

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j.urnal of Thermal Science 2020年第6期29卷 1513-1530页

作者： SINGH Ranj.t j. GOHIL Trushar B. Department of Mechanical Engineering Visvesvaraya National Institute of TechnologyNagpur 440010India

The present study reveals the significance of the magnetic field or Lorentz force on the unsteady natural convection flow and heat transfer in the suddenly expanded *** Lorentz force based magnetohydrodynamics(MHD)solver using electric potential formulation coupled with the energy equation by the means of Boussinesq approximation is developed in the open-source CFD tool *** unsteady flow is generated by the buoyancy force keeping the Rayleigh number(Ra)at 109,at the fixed Prandtl number(Pr)of *** effects of the magnetic field on the flow and heat transfer are explained for various orientations of magnetic field(Bx,B45,and By)in terms of Hartmann number(Ha=0,50,100,300 and 500).The increase in the magnetic field increases the strength of the Lorentz force,which regulates the flow pattern and suppresses down the unsteady nature of flow and heat transfer into the *** is perceived that the average Nusselt number decreases as the intensity of Bx and B45 magnetic field ***,for By magnetic field the average Nusselt number increases up to Ha of 100 as compared to the non-MHD case(Ha=0).The distribution of Lorentz force in the domain plays a significant role in the governing of the fluid flow and heat transfer.

关键词： OpenFOAM Lorentz force Boussinesq approximation natural convection

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FIBONACCI SEQUENCE AND CANTOR'S TERNARY SET

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Chinese Annals of Mathematics,Series B 1998年第1期19卷 129-132页

作者： TONG j.NGCHENG SAMONS ,j. Univ N Florida Dept Math & Stat Jacksonville FL 32224 USA

Let N be the set of positive integers and C be Cantor's ternary set. A function xi : N --> [0, 1] is established by the help of the Fibonacci sequence such that , the closure of the set xi(N), is homeomorphic to the s... 详细信息

关键词： Fibonacci sequence Cantor′s ternary set Homeomorphic

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Mountain Water Tower and Ecological Risk Estimation of the Mesta-Nestos Transboundary River Basin (Bulgaria-Greece)

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j.urnal of Mountain Science 2007年第3期4卷 209-220页

作者： K. Grunewald j. Scheithauer j.-M. Monget N. Nikolova Landscape Research Centre Dresden Ecole des Mines de Paris South-West University Blagoevgrad

The Mesta-Nestos river basin in Bulgaria and Greece is a case study for transboundary decision-making support in south-eastern Europe and a show-case for the development of methodologies and information-gathering for the integrated regional planning of water resources. Land-use conflicts in this water-scarce region cover a wide spectrum of activities like agricultural irrigation, drinking water production, diversions for industrial water, and risk of pollution from mining, to name a few examples. Measurements of the water quality were carried out in the upper basin. Results will be illustrated by the example of the environmental situation in the alpine region of the Pirin National Park as well as in the Razlog Basin with a stronger anthropogenic impact and pollution around a former uranium mine near the village of Elesnica. The social and economic development of this transboundary region is a recently established priority for mean an increase in water usage the water resources if regional the future. It will and more stress for impacts of global climate change are verified. Problem-focused management of the catchment area as a whole on the basis of proved geo-data sets is needed for the future.

关键词： Environment interactions nutrients pollutants resource management Southeast Europe uranium water quality Pirin high Mountains

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