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阳极极化条件下碳钢在3.5% NaCl溶液中的氢渗透行为

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阳极极化条件下碳钢在3.5% NaCl溶液中的氢渗透行为

Laser-induced plasma formation in water with up to 400 mj double-pulse LIBS

2018年全国腐蚀电化学及测试方法学术交流会

作者：黄彦良刘相局张琦超 hans-j?rg kunte Wolfgang Sand 中国科学院海洋研究所中国科学院海洋坏境腐蚀与生物污损重点实验室中国科学院海洋大科学研究中心青岛海洋科学与技术国家实验室海洋腐蚀与防护开放工作室中国科学院大学 Federal Institute for Materials Research and Testing Donghua University College of Environmental Science and Engineering Technical University and Mining Academy Freiberg University Duisburg-Essen

氢对钢铁材料的环境敏感断裂起着重要作用。氢致开裂(HAC)问题一直是高强度钢发展的主要技术问题之一,因为HAC问题的发生与其强度水平成正比[1]。在许多领域为降低建筑材料总重量对高强度钢需求增加[2]。由于绿色发展战略的实施,高强度...

氢对钢铁材料的环境敏感断裂起着重要作用。氢致开裂(HAC)问题一直是高强度钢发展的主要技术问题之一,因为HAC问题的发生与其强度水平成正比[1]。在许多领域为降低建筑材料总重量对高强度钢需求增加[2]。由于绿色发展战略的实施,高强度钢在海上设施中的应用也将具有相同的发展趋势,即通过使用较少的材料来满足相同的强度要求。由于碳钢在海洋环境中的腐蚀较严重,钢结构一般要采用阴极保护进行防护[3]。然而,不适当的阴极保护可能导致这些高强度钢在海水中因氢脆失效,这是由于施加的过负电位导致的氢渗透。在本文作者最近进行的实验研究中,通过在3.5%NaCl溶液和在含有耗氢微生物的溶液中对碳钢施加不同的极化电位确定氢渗透明显增加的电位时发现,阳极电位下氢渗透电流也增加,如图1所示。这一现象引起了作者的关注和兴趣。阴极电位下的氢渗透研究得较多[4],但阳极极化下的氢渗透研究很少见。文献检索表明,Flis和Zakrozymyski等人在铁薄膜于弱碱和中性溶液(碳酸盐/碳酸氢盐,磷酸盐,乙酸盐溶液)中弱阳极极化下观察到氢渗透电流峰,但增强的氢渗透之前阴极预极化。认为由于加速的阳极氧化使金属表面得到更新、由于铁氧化引起近金属表面溶液的酸化以及可能催化析氢反应的氧化物/氢氧化物的形成促进了氢进入金属中[5]。我们所用的溶液和实验方法不同于等人采用的方法[5]。我们所采用的极化电位是强阳极极化电位。强阳极极化下的氢渗透电流无法用Flis和Zakrozymyski等人提出的机理来解释[5]。碳钢在3.5%NaCl溶液中的腐蚀产物多孔疏松,不能附着在试样表面。溶液中微量的腐蚀产物使表观pH降低是值得怀疑的。更重要的是,随着阳极电位的增加,析氢反应受到抑制。为了确认在3.5%NaCl溶液中阳极极化下的氢渗透现象,使用供应态和真空退火的片状试样仔细进行了实验。结果和分析表明,阳极极化下观察到的氢渗透电流来源于阳极极化下试样中氢的释放。所观察到的现象有望发展为确定钢中氢浓度测量的新技术。

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来源： cnki会议评论

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Plasma Science and Technology 2024年第1期26卷 93-100页

作者： Marion HENKEL Michelle SIEMENS Ralf METHLING Benjamin EMDE jörg HERMSDORF Steffen FRANKE Diego GONZALEZ Leibniz Institute for Plasma Science and Technology(INP) Felix-Hausdorff-Straße 2Greifswald 17489Germany Laser Zentrum Hannover e.V.(LZH) Hollerithallee 8Hannover 30419Germany

Double-pulse LIBS is a promising technique for deep-sea *** measurements in shallow water with up to 400 mj each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can *** emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic *** has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.

关键词： double-pulse LIBS underwater plasma formation emission spectrosocpy

Graphene-calcium carbonate coating to improve the degradation resistance and mechanical integrity of a biodegradable implant

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journal of Magnesium and Alloys 2024年第1期12卷 394-404页

作者： Lokesh Choudhary Parama Chakraborty Banerjee R.K.Singh Raman Derrek E.Lobo Christopher D.Easton Mainak Majumder Frank Witte jörg F.Löffler Department of Mechanical and Aerospace Engineering Monash UniversityClayton CampusMelbourneVIC 3800Australia Department of Chemical and Biological Engineering Monash UniversityClayton CampusMelbourneVIC 3800Australia Nanoscale Science and Engineering Laboratory(NSEL) Bldg 37Monash UniversityClayton CampusMelbourneVIC 3800Australia CSIRO Materials Science and Engineering Bayview AvenueClaytonVIC 3168Australia julius Wolff Institute and Berlin Brandenburg Center for Regenerative Therapies Charité–Universitätsmedizin BerlinAugustenburger Platz 113353 BerlinGermany Laboratory of Metal Physics and Technology Department of MaterialsETH Zurich8093 ZurichSwitzerland

Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body *** necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical *** this study,an AZ91 magnesium alloy,as a representative for a biodegradable Mg implant material,was modified with a thin reduced graphene oxide(rgO)-calcium carbonate(CaCO_(3))composite *** analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity,and thus has the potential to greatly extend the related application field.

关键词： Graphene coating Biodegradable implant Hydroxyapatite Corrosion Magnesium alloy

From Single Droplet to Column Design

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Tsinghua Science and Technology 2006年第2期11卷 212-216页

作者： hans-jrg Bart Institute of Thermal Process Engineering TU Kaiserslautern D-67653 Kaiserslautern Germany

The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the dispersion coefficient accounts for all hydrodynamic non-idealities. A new approach uses single droplet experiments to obtain the basic laws and functions governing droplet breakage, coalescence, relative velocity, and axial dispersion when using droplet populance balance models （DPBM）. The hydrodynamics simulation results show that the mean Sauter diameter, hold-up, and concentration profiles could be well predicted, which promotes the use of DPBM models for further applications in industrial scale.

关键词： single droplet column design countercurrent extraction droplet populance balance model

Dynamics and functions of E‑cadherin complexes in epithelial cell and tissue morphogenesis

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Marine Life Science & Technology 2023年第4期5卷 585-601页

作者： Na Zhang Matthias Häring Fred Wolf jörg Großhans Deqing Kong Department of Biology Philipps University35043 MarburgGermany Göttingen Campus Institute for Dynamics of Biological Networks(CIDBN) Georg August University Göttingen37073 GöttingenGermany

Cell–cell adhesion is at the center of structure and dynamics of epithelial tissue.E-cadherin–catenin complexes mediate Ca^(2+)-dependent trans-homodimerization and constitute the kernel of adherens *** the basic function of cell–cell adhesion,recent progress sheds light the dynamics and interwind interactions of individual E-cadherin–catenin complex with E-cadherin superclusters,contractile actomyosin and mechanics of the cortex and *** nanoscale architecture of E-cadherin complexes together with cis-interactions and interactions with cortical actomyosin adjust to junctional tension and mechano-transduction by reinforcement or weakening of specific features of the *** post-translational modifications such as phosphorylation and glycosylation have been implicated,their role for specific aspects of in E-cadherin function has remained ***,we provide an overview of the E-cadherin complex in epithelial cell and tissue morphogenesis focusing on nanoscale architectures by super-resolution approaches and post-translational modifications from recent,in particular in vivo,***,we review the computational modelling in E-cadherin complexes and highlight how computational modelling has contributed to a deeper understanding of the E-cadherin complexes.

关键词： Nanoscale architectures Phosphorylation Glycosylation Computational modelling

Conditional Generative Adversarial Networks for modelling fuel sprays

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能源与人工智能(英文) 2023年第2期12卷 62-75页

作者： Cihan Ates Farhad Karwan Max Okraschevski Rainer Koch hans-jörg Bauer Karlsruhe Institute of Technology(KIT) Institute of Thermal TurbomachineryGermany Karlsruhe Institute of Technology(KIT) Machine Intelligence in Energy SystemsGermany

In this study, the probabilistic, data driven nature of the generative adversarial neural networks (GANs)was utilized to conduct virtual spray simulations for conditions relevant to aero engine combustors. Themodel consists of two sub-modules: (i) an autoencoder converting the variable length droplet trajectories intofixed length, lower dimensional representations and (ii) a Wasserstein GAN that learns to mimic the latentrepresentations of the evaporating droplets along their lifetime. The GAN module was also conditioned withthe injection location and the diameters of the droplets to increase the generalizability of the whole *** training data was provided from highly resolved 3D, transient Eulerian–Lagrangian, large eddy simulationsconducted with OpenFOAM. Neural network models were created and trained within the open source machinelearning framework of PyTorch. Predictive capabilities of the proposed method was discussed with respect tospray statistics and evaporation dynamics. Results show that conditioned GAN models offer a great potentialas low order model approximations with high computational efficiency. Nonetheless, the capabilities of theautoencoder module to preserve local dependencies should be improved to realize this potential. For the currentcase study, the custom model architecture was capable of conducting the simulation in the order of secondsafter a day of training, which had taken one week on HPC with the conventional CFD approach for the samenumber of droplets (200,000 trajectories).

关键词： Generative Adversarial Networks Generative learning Fuel injection Aero engines Multivariate time series

High-dimensional neural network potentials for magnetic systems using spin-dependent atom-centered symmetry functions

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npj Computational Materials 2021年第1期7卷 1541-1551页

作者： Marco Eckhoff jörg Behler Universität Göttingen Institut für Physikalische ChemieTheoretische ChemieTammannstrasse 637077 GöttingenGermany Universität Göttingen International Center for Advanced Studies of Energy Conversion(ICASEC)Tammannstrasse 637077 GöttingenGermany

Machine learning potentials have emerged as a powerful tool to extend the time and length scales of first-principles quality ***,most machine learning potentials cannot distinguish different electronic spin arrangements and thus are not applicable to materials in different magnetic *** we propose spin-dependent atom-centered symmetry functions as a type of descriptor taking the atomic spin degrees of freedom into *** used as an input for a high-dimensional neural network potential(HDNNP),accurate potential energy surfaces of multicomponent systems can be constructed,describing multiple collinear magnetic *** demonstrate the performance of these magnetic HDNNPs for the case of manganese oxide,*** method predicts the magnetically distorted rhombohedral structure in excellent agreement with density functional theory and *** efficiency allows to determine the Néel temperature considering structural fluctuations,entropic effects,and *** method is general and is expected to be useful also for other types of systems such as oligonuclear transition metal complexes.

关键词： magnetic symmetry neural

Development of ^(18)F-labeled radiotracers for neuroreceptor imaging with positron emission tomography

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Neuroscience Bulletin 2014年第5期30卷 777-811页

作者： Peter Brust jrg van den Hoff jrg Steinbach Helmholtz-Zentrum Dresden-Rossendorf Institute of Radiopharmaceutical Cancer ResearchPermoserstrasse 15Leipzig04318Germany

Positron emission tomography （PET） is an in vivo molecular imaging tool which is widely used in nuclear medicine for early diagnosis and treatment follow-up of many brain diseases. PET uses biomolecules as probes which are labeled with radionuclides of short half-lives, synthesized prior to the imaging studies. These probes are called radiotracers. Fluorine-18 is a radionuclide routinely used in the radiolabeling of neuroreceptor ligands for PET because of its favorable half-life of 109.8 min. The delivery of such radiotracers into the brain provides images of transport, metabolic, and neurotransmission processes on the molecular level. After a short introduction into the principles of PET, this review mainly focuses on the strategy of radiotracer development bridging from basic science to biomedical application. Successful radiotracer design as described here provides molecular probes which not only are useful for imaging of human brain diseases, but also allow molecular neuroreceptor imaging studies in various small-animal models of disease, including genetically- engineered animals. Furthermore, they provide a powerful tool for in vivo pharmacology during the process of pre-clinical drug development to identify new drug targets, to investigate pathophysiology, to discover potential drug candidates, and to evaluate the pharmacokinetics and pharmacodynamics of drugs in vivo.

关键词： Alzheimer's disease autoradiography blood-brain barrier brain tumor cholinergic system kinetic modeling metabolism molecular imaging neurodegeneration positron emission tomography precursor psychiatric disorder radiotracer sigma receptor

Tracking moving magnetic features in the photosphere

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Science China(Physics,Mechanics & Astronomy) 2009年第11期52卷 1737-1748页

作者： BCHNER jrg Max-Planck-Institut fr Sonnensystemforschung

This research aims for an objective identification, tracking, and a statistical analysis of the Moving Magnetic Features (MMFs) around sunspots using SOHO/MDI high-resolution magnetograms. To this end, we develop a computerized tracking program and study the motion and magnetism of the outflows of MMFs around 26 sunspots. Our method locates 4-27 MMFs per hour, with higher counts for large sunspots. We differentiate MMFs into type α that have a polarity opposite to the parent sunspots, and type β that share the sunspot's polarity. These sunspots' MMF subsets exhibit a wide range of central tendencies which have distinctive correlations with the sunspots. In general, α-MMFs emerge farther from the sunspot, carry less flux, and move faster than β-MMFs. The typical α/β-MMFs emerge at 2.2 - 8.1/0.1 - 3.2 Mm outside the penumbra limb, with lifetimes of 1.1 - 3.1/1.3 - 2.0 h. They are 1.1 - 6.6/1.4 - 3.6 Mm2 in area and carry 1.4 - 12.5/4.8 - 11.4 ×1018 Mx of flux. They travel a distance of 2.7 - 5.9/2.8 - 3.6 Mm with the speed of 0.5 - 0.9/0.4 - 0.7 km/s. Compared to the α-MMFs produced by large sunspots, those of small spots are smaller. They emerge closer to sunspot, move farther, live longer, and carry less flux. β-MMFs show much less correlation with the sunspots. The flux outflow carried by the MMFs ranges from 0.2 to 8.3 × 1019Mx· h-1 and does not show obvious correlation with the sunspots' evolution. The frequency distributions of the MMFs' distance traveled, area, and flux are exponential. This suggests the existence of numerous small, weak, and short-timescale magnetic objects which might contribute to the sunspot flux outflow.

关键词： sun activity magnetic fields photosphere sunspots moat moving magnetic features