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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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Experimental measurements of gamma-photon production and estimation of electron/positron production on the PETAL laser facility

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Matter and Radiation at Extremes 2024年第5期9卷 32-47页

作者： F.Brun L.Ribotte G.Boutoux X.davoine P.E.Masson-Laborde Y.Sentoku N.Iwata N.Blanchot d.Batani I.Lantuéj.ul L.Lecherbourg B.Rosse C.Rousseaux B.Vauzour d.Raffestin E.d’Humières X.Ribeyre Centre Lasers Intenses et Applications UMR 5107Universitéde Bordeaux-CNRS-CEA33405 TalenceFrance CEA DAMCESTAF-33116 Le BarpFrance CEA DAMDIFF-91297 ArpajonFrance CEA LMCEUniversitéParis-Saclay91680 Bruyères-le-ChâtelFrance Institute of Laser Engineering Osaka University2-6 YamadaokaSuitaOsaka 565-0871Japan

This article reports the first measurements of high-energy photons produced with the high-intensity PETawatt Aquitaine Laser(PETAL)*** experiments were performed during the commissioning of the *** laser had an energy of about 400 j.an intensity of 8×10^(18)W cm^(−2),and a pulse duration of 660 fs(FWHM).It was shot at a 2 mm-thick solid tungsten *** high-energy photons were produced mainly from the bremsstrahlung process for relativistic electrons accelerated inside a plasma generated on the front side of the *** paper reports measurements of electrons,protons and *** electrons up to35 MeV with a few-MeV temperature were recorded by a spectrometer,called SESAME(SpectreÉlectronS Angulaire MoyenneÉnergie).K-and L-shells were clearly detected by a photon spectrometer called SPECTIX(Spectromètre PetalàCristal en TransmIssion pour le rayonnnement X).High-energy photons were diagnosed by CRACC-X(Cassette de RAdiographie Centre Chambre-rayonnement X),a bremsstrahlung *** cannon analysis is strongly dependent on the hypothesis adopted for the spectral *** shapes can exhibit similar reproductions of the experimental *** eliminate dependence on the shape hypothesis and to facilitate analysis of the data,simulations of the interaction were *** model the mechanisms involved,a simulation chain including hydrodynamic,particle-in-cell,and Monte Carlo simulations was *** simulations model the preplasma generated at the front of the target by the PETAL laser prepulse,the acceleration of electrons inside the plasma,the generation of MeV-range photons from these electrons,and the response of the detector impacted by the energetic photon *** this work enabled reproduction of the experimental *** high-energy photons produced have a large emission angle and an exponential distribution *** addition to the analysis of the photon spectra,positron production was also ***,if high

关键词： process. positron hypothesis

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Stochastic seismic inversion and Bayesian facies classification applied to porosity modeling and igneous rock identification

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Petroleum Science 2024年第2期21卷 918-935页

作者： Fábio j.nior damasceno Fernandes Leonardo Teixeira Antonio Fernando Menezes Freire Wagner Moreira Lupinacci Exploratory Interpretation and Reservoir Characterization Group(GIECAR) Department of Geology and GeophysicsFederal Fluminense UniversityNiter oiRJ24210-346Brazil Petrobras Rio de JaneiroRJ20231-030Brazil National Institute of Science and Technology of Petroleum Geophysics(INCT-GP/CNPQ) Niter oiRJ24210-346Brazil

We apply stochastic seismic inversion and Bayesian facies classification for porosity modeling and igneous rock identification in the presalt interval of the Santos Basin. This integration of seismic and well-derived information enhances reservoir characterization. Stochastic inversion and Bayesian classification are powerful tools because they permit addressing the uncertainties in the model. We used the ES-MdA algorithm to achieve the realizations equivalent to the percentiles P10, P50, and P90 of acoustic impedance, a novel method for acoustic inversion in presalt. The facies were divided into five: reservoir 1,reservoir 2, tight carbonates, clayey rocks, and igneous rocks. To deal with the overlaps in acoustic impedance values of facies, we included geological information using a priori probability, indicating that structural highs are reservoir-dominated. To illustrate our approach, we conducted porosity modeling using facies-related rock-physics models for rock-physics inversion in an area with a well drilled in a coquina bank and evaluated the thickness and extension of an igneous intrusion near the carbonate-salt interface. The modeled porosity and the classified seismic facies are in good agreement with the ones observed in the wells. Notably, the coquinas bank presents an improvement in the porosity towards the top. The a priori probability model was crucial for limiting the clayey rocks to the structural lows. In Well B, the hit rate of the igneous rock in the three scenarios is higher than 60%, showing an excellent thickness-prediction capability.

关键词： Stochastic inversion Bayesian classification Porosity modeling Carbonate reservoirs Igneous rocks

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High power generation of adaptive laser beams in a Nd：YVO4 MOPA system

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Chinese Optics Letters 2017年第12期15卷 24-28页

作者： S. H. Noh d. j. Kim j. W. Kim department of Photonics and Nanoelectronics Hanyang University ERICA Ansan 15588 South Korea

We report efficient power scaling of the laser output with an adaptive bemn profile from an Nd：YAG dual-cavity master oscillator using a three-stage end-pumped Nd：YVO4 amplifier. We succeed ill the last switching of an excited laser mode by modulating an acousto-optic modulator loss in a dual-cavity master oscillator, thereby achieving temporal modulation of the output beam profile. The outputs from the master oscillator are amplified via a three-stage power amplifier yielding 36.6, 40.5, and 45.4 W of the maximum output at 116.8 W of incident pump power for the transverse electromagnetic, Laguerre-Gaussian, and quasi-top-hat beam, respectively. The prospects for further power scaling and applications via the dual-cavity master-oscillator power-amplifier （MOPA） system are considered.

关键词： High power generation of adaptive laser beams in a Nd:YVO4 MOPA system Nd

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Granger causal representation learning for groups of time series

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Science China(Information Sciences) 2024年第5期67卷 56-68页

作者： Ruichu CAI Yunj.n WU Xiaokai HUANG Wei CHEN Tom Z.j.FU Zhifeng HAO School of Computer Science Guangdong University of Technology Peng Cheng Laboratory College of Science Shantou University

discovering causality from multivariate time series is an important but challenging *** existing methods focus on estimating the Granger causal structures among multivariate time series,while ignoring the prior knowledge of these time series, e.g., the group of the time series. Focusing on discovering the Granger causal structures among groups of time series, we propose a Granger causal representation learning method to solve this problem. First, we use the multiset canonical correlation analysis method to learn the Granger causal representation of each group of time series. Then, we model the Granger causal relationships among the learned Granger causal representations using a recurrent neural network with temporal information. Finally, we formulate the above two stages into one unified optimization problem, which is efficiently solved using the augmented Lagrangian method. We conduct extensive experiments on synthetic and real-world datasets to validate the correctness and effectiveness of the proposed method.

关键词： Granger causal discovery Granger causal representation learning time series data recurrent neural network multiset canonical correlation analysis

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Lighting up aggregate emission of perylene diimide by leveraging polymerization-mediated through-space charge transfer and π-π stacking

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Science China Chemistry 2024年

作者： Suiying Ye désirée Füglistaller Tian Tian Anj.y Manian Sudhir Kumar Celine Nardo Andrew j.Christofferson Salvy P.Russo Chih-j.n Shih j.an-Christophe Leroux Yinyin Bao Institute of Pharmaceutical Sciences Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 3 Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1-5 ARC Centre of Excellence in Exciton Science School of Science RMIT University School of Science STEM College RMIT University

The molecular engineering of fluorescent organic/polymeric materials, specifically those emitting in the deep red to near-infrared spectrum, is vital for advancements in optoelectronics and biomedicine. Perylene diimide(PdI), a well-known fluorescent scaffold, offers high thermal and photophysical stability but suffers from fluorescence quenching in solid or aggregate states due to intense π-π interactions. To mitigate this, simple and versatile methods for strong PdI aggregate emission without extensive synthetic demands are highly desirable but still lacking. Here, we report a straightforward strategy to enhance the solid-state emission of PdI by introducing certain degree of through-space charge transfer(TSCT) via controlled radical polymerization,which can efficiently distort the typical face-to-face PdI stacking, enabling greatly enhanced deep red emission. This is achieved by growing electron-donating star-shape styrenic(co)polymers from a multidirectional electron-accepting PdI initiator. The incorporation of polycyclic aromatic monomers further shifted the emission into the near-infrared region, albeit with a reduced intensity. Overall, the emission of the PdI-based TSCT polymers can be systematically manipulated by leveraging the balance between PdI stacking and the TSCT degree, as confirmed by both experimental study and theoretical calculations. Our approach circumvents complex synthetic procedures, offering highly emissive materials with large Stokes shifts and showing broad potential for optoelectronic technology.

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dissecting the dendritic cell controversy in chronic hepatitis B virus infection

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Cellular & Molecular Immunology 2015年第3期12卷 283-291页

作者： Adam j. Gehring j.ne Ann d'Angelo Molecular Microbiology and Immunology Saint Louis University School of Medicine Saint Louis MO USA Saint Louis University Liver Center SaintLouis University School of Medicine Saint Louis MO USA

Therapeutic vaccines to boost endogenous T-cell immunity rely on the stimulatory capacity of dendritic cells （dCs）. The functionality of dCs in chronic hepatitis B virus （HBV） infection has been a long-standing debate. Therefore, we have attempted to summarize multiple studies investigating dC function in chronic HBV patients to determine whether common observations can be drawn. We found that the frequency and function of ex vivo-tested myeloid and plasmacytoid dCs were largely intact in patients with HBV infection and similar to those of healthy donor dCs. The main exception was reduced IFN-a production by plasmacytoid dC from chronic HBV patients. This reduced IFN-a production correlated with liver inflammation in multiple studies but not with viral load, suggesting that viral antigens have little effect on dC function. The maj.rity of the confusion about dC function arises from studies reporting the reduced function of healthy donor dCs exposed to various sources of H BV in vitro. These direct effects of viral antigens are in contrast to data from HBV-infected patients. The variations in the assays used and areas that reauire further investigation are also covered

关键词： Hepatitis B virus dendritic Cell Vaccination

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A Room-Temperature Chloride-Conducting Metal-Organic Crystal[Al(dMSO)_(6)]Cl_(3) for Potential Solid-State Chloride-Shuttle Batteries

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Energy & Environmental Materials 2024年第1期7卷 107-113页

作者： Bing Wu j.n Luxa j.ří Šturala Shuangying Wei Lukáš děkanovský Abhilash Karuthedath Parameswaran Min Li Zdenek Sofer department of Inorganic Chemistry University of Chemistry and Technology PragueTechnická 516628Prague Czech Republic

The growing demand for substitutes of lithium chemistries in battery leads to a surge in budding novel anion-based electrochemical energy storage,where the chloride ion batteries(CIBs)take over the *** application of CIBs is limited by the dissolution and side reaction of chloride-based electrode materials in a liquid *** the flipside,its solid-state electrolytes are scarcely reported due to the challenge in realizing fast Cl^(-)*** present study reports[Al(dMSO)_(6)]Cl_(3),a solid-state metal-organic material,allows chloride ion *** strong Al-Cl bonds in AlCl_(3)are broken down after coordinating of Al^(3+)by ligand dMSO,and Cl^(-)in the resulting compound is weakly bound to complexions[Al(dMSO)_(6)]^(3+),which may facilitate Cl^(-)*** partial replacement of Cl^(-)with PF_(6)^(-),the room-temperature ionic conductivity of as-prepared electrolyte is increased by one order of magnitude from 2.172×10^(-5)S cm^(-1)to 2.012×10^(-4)S cm^(-1).When they are assembled with Ag(anode)/Ag-AgCl(cathode)electrode system,reversible electrochemical redox reactions occur on both sides,demonstrating its potential for solid-state chloride ion *** strategy by weakening the bonding interaction using organic ligands between Cl^(-)and central metallic ions may provide new ideas for developing solid chloride-ion conductors.

关键词： [Al(dMSO)_(6)]Cl_(3) chloride-ion batteries ionic conductivity metal-organic solid-state electrolytes

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Agglomeration Mechanism of Rich Hematite Sinter with Lowering SiO_2 Content

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International j.urnal of Minerals,Metallurgy and Materials 2000年第4期14卷 256-260页

作者： duan d. Gong Y. Wang j. Metallurgy School University of Science and Technology Beijing Beijing 100083 China High Technology and Research development Center Ministry of Science and Technology Beijing 100862 China

The mini-sintering test was introduced. The experiments of specimens of rich hematite with lowering SiO2 content were carried out by the mini-sintering test. The strength and mechanism of agglomeration were studied mainly when silica content in sintered specimens was decreased gradually. The relationships between SiO2 volume and morphology of sinter were also investigated. It is considered that high grade sinter can be developed by raising sinter basicity so as to enhance complex calcium ferrite content or lowering sinter basicity so as to make Fe2O3 bonding for strength.

关键词： SiO Rich Agglomeration Mechanism of Rich Hematite Sinter with Lowering SiO2 Content

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A Bayesian Network Approach for Offshore Risk Analysis Through Linguistic Variables

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China Ocean Engineering 2007年第3期21卷 371-388页

作者： Ren j. Wang j. j.nkinson I. Xu d. L. Yang j. B. School of Engineering Liverpool John Moores University Liverpool L 3 3 AF UK Manchester Business School The University of Manchester Manchester M 60 1 QD UK

This paper presents a new approach for offshore risk analysis that is capable of dealing with linguistic probabilities in Bayesian networks （ BNs）. In this paper, linguistic probabilities are used to describe occurrence likelihood of hazardous events that may cause possible accidents in offshore operations. In order to use fuzzy information, an f-weighted valuation function is proposed to transform linguistic j.dgements into crisp probability distributions which can be easily put into a BN to model causal relationships among risk factors. The use of linguistic variables makes it easier for human experts to express their knowledge, and the transformation of linguistic j.dgements into crisp probabilities can significantly save the cost of computation, modifying and maintaining a BN model. The flexibility of the method allows for multiple forms of information to be used to quantify model relationships, including formally assessed expert opinion when quantitative data are lacking, or when only qualitative or vague statements can be made. The model is a modular representation of uncertain knowledge caused due to randomness, vagueness and ignorance. This makes the risk analysis of offshore engineering systems more functional and easier in many assessment contexts. Specifically, the proposed f-weighted valuation function takes into account not only the dominating values, but also the a-level values that are ignored by conventional valuation methods. A case study of the collision risk between a Floating Production, Storage and Off-loading （FPSO） unit and the anthorised vessels due to human elements during operation is used to illustrate the application of the proposed model.

关键词： Risk analysis fiweighted valuation function Bayesian networks fuzzy number linguistic probability off-shore engineering systems

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