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New Developments in Thermo-Chemical Diffusion Processes

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材料热处理学报 2004年第5期25卷 13-19页

作者： bernd Edenhofer Ipsen International GmbH Kleve Germany

Thermo-chemical diffusion processes like carburising, nitriding and boronizing play an important part in modern manufacturing technologies. They exist in many varieties depending on the type of diffusing element used and the respective process procedure. The most important industrial heat treatment process is case-hardening, which consists of thermochemical diffusion process carburising or its variation carbonitriding, followed by a subsequent quench. The latest developments of using different gaseous carburising agents and increasing the carburising temperature are one main area of this *** other area is the evolvement of nitriding and especially the ferritic nitrocarburising process by improved process control and newly developed process variations using carbon, nitrogen and oxygen as diffusing elements in various process steps. Also boronizing and special thermo-chemical processes for stainless steels are discussed.

关键词：热化学扩散高温渗碳渗氮位控制溶体渗氮

Effects of temperature and sodium carboxylate additives on mineralization of calcium oxalate in silica gel systems

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Science China Chemistry 2004年第4期47卷 311-319页

作者： bernd Tieke Institut fur Physikalische Chemie Universitt zu Kln Luxemburgerstr. 116 D-50939 Kln Germany

The effects of temperature and multifunctional sodium carboxylate additives on the phase composition and morphology of calcium oxalate (CaOxa) crystals grown in silica gel system were systematically investigated using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and Fourier-transform infrared spectra (FT-IR). The sodium carboxylates investigated include: monocarboxylate sodium acetate (NaAc), disodium tartrate (Na2tart), trisodium citrate (Na3cit), and the disodium salt of ethylenediaminetetraacetic acid (Na2edta). The temperature range was from 7°C to 67°C. The crystallization temperature affects the phase compositions, the growth rate, and the morphology of CaOxa. First, the logarithm of the percentage of calcium oxalate dihydrate (COD) formed at a certain temperature (T) is proportional to the reciprocal of temperature (1/T). Second, the weight of CaOxa crystals decreases as decreasing the temperature. At a given temperature, the ability of the sodium carboxylates to induce COD follows the order: Na2edta Na3cit Na2tart NaAc. Third, the multicarboxylates can decrease the surface area of calcium oxalate monohydrate (COM). It makes the edges and tips of COM crystals blunt and oval. All the three changes, an increase of the content of COD, a decrease of the weight of CaOxa crystals, and a decrease of the surface area of COM crystals, can inhibit the formation of CaOxa stones. These results support the clinical use of citrates and may be helpful in elucidating the mechanisms of the formation of CaOxa calculus. Keywords calcium oxalate - sodium carboxylate - gel - urinary calculi - crystallization - biomineralization

关键词： calcium oxalate sodium carboxylate gel urinary calculi crystallization biomineralization

Improvement,validation and application of CFD/DEM model to dense gas-solid flow in a fluidized bed

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Particuology 2013年第5期11卷 514-526页

作者： Falah Alobaid bernd Epple TU Darmstadt Energiesysteme und EnergietechnikPetersenstrasse 3064287 DarmstadtGermany

Dense gas-solid flow with solid volume fraction greater than 10% and at moderate Reynolds number is important in many industrial facilities such as fluidized beds. In this work, the Euler-Lagrange approach in combination with a deterministic collision model is applied to a laboratory-scale fluidized bed. The fluid-particle interaction is studied using a new procedure called the offset method, which results in several numbers of spatial displacements of the fluid grid. The proposed method is highly precise in determining porosity and momentum transfer, thus improving simutation accuracy. A validation study was carried out to assess the results using this in-house CFD/DEM code against 5-s operation of a Plex- iglas spouted-fluidized bed, showing good qualitative correlation of solid distribution in the bed and acceptable quantitative agreement of pressure drops at different positions in the bed. In view of high computing cost, special emphasis is placed on effective program design, such as application of advanced detection algorithm for particle-particle/wall collisions, the multi-grid method and parallel calculation. In this context, the influence of increasing the processor number, up to 36, on calculation efficiency was investigated.

关键词： Dense gas-solid flowComputational fluid dynamicsDiscrete element methodOffset methodParallelisation

Ferrimagnetic ceramic adsorbents for cleanup of H_2S from exhaust gases

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China Particuology 2007年第1期5卷 156-161页

作者： bernd Halbedel Apostolos Kontogeorgakos Institute of Materials Science Glass and Ceramic Technology Group Technische Universitt Ilmenau P.O. Box 10 05 65 D-98684 Ilmenau Germany NCSR "Demokritos" Institute of Materials Science 15310 Aghia Paraskevi Attiki Greece

Adsorbents that exhibit magnetic properties in addition to other required process-relevant characteristics open up new perspectives for the dry reduction and/or elimination of HES and other sulfur compounds from exhaust gases. These adsorbents eliminate the sulfur compounds from exhaust gases by virtue of their coatings and their magnetic property which makes it possible the use of magnetically assisted and stabilized fluidization in an externally applied magnetic field. In the present paper, the feasibility of the sorptive function of porous ceramic ferrimagnetic beads is ensured by sol-gel coating of zinc oxide without the formation of Zn-Fe-oxides and without considerable decrease of available pore volume. The results of material characterization by SEM, Auger electron spectroscopy, X-ray and mercury-porosity measurements and the loading capacity of a HES/N2 model gas are presented and discussed. The resulting HES loading of the functionalized adsorbent beads is more than 10 times larger than that of the starting material. @ 2007 Chinese Society of Particuolo^v and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.

关键词： Adsorption Adsorbents Ferrites Magnetic materials Magnetic properties Sol-gel Zinc oxide

New Zircon U-Pb Geochronology of the Post-kinematic Granitic Plutons in the Diancang Shan Metamorphic Massif along the Ailao Shan-Red River Shear Zone and Its Geological Implications

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Acta Geologica Sinica(English Edition) 2010年第6期84卷 1474-1487页

作者： bernd LEISS Geoscience Centre of the University of Gttingen Goldschmidt stress 337077 GttingenGermany

The Ailao Shan-Red River fault zone is the boundary between the Yangtze block to the northeast and the Indochina block to the *** is an important tectonic zone due to its role in the southeastward extrusion of the Indochina block during and subsequent to the Indian-Eurasian *** Shan(DCS) high-grade metamorphic complex,located at the northwest extension along the Ailao Shan-Red River(ASRR) shear zone,is a representative metamorphic complex of the ASRR tectonic *** and microstructural analysis of sheared rocks in the high-grade metamorphic rocks reveals that they are coherent with solid-state high-temperature ductile deformation,which is attributed to left-lateral shearing along the ASRR shear *** LA-ICP-MS zircon U-Pb geochronological and microstructural studies of the post-kinematic granitic plutons provide a straightforward time constraint on the termination ductile left-lateral shearing and exhumation of the metamorphic massif in the ASRR shear *** is suggested that the left-lateral shearing along the ASRR shear zone ended at ca.21 Ma at relative lower-temperature or decreasing temperature *** or after the emplacement of the young dikes at ca.21 Ma,rapid brittle deformation event occurred,which makes the DCS massif start fast uplift/exhumation and cooling to a shallow crustal level.

关键词： high-temperature mylonites Diancang Shan metamorphic massif Ailao Shan-Red River shear zone timing of left-lateral ductile shearing geochronology

A genome-wide screening for DNA repair genes:much more players than hitherto known

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Signal Transduction and Targeted Therapy 2020年第1期5卷 806-807页

作者： bernd Kaina Institute of Toxicology University Medical CenterObere Zahlbacher Str.67MainzGermany

Since the discovery of the structure of DNA and the statement by Francis Crick that DNA is“…so precious that probably many distinct repair mechanisms would exist”,1 a plethora of DNA alterations induced by exogenous and endogenous genotoxins has been identified,together with complex cellular processes that sense the damage,remove it from the macromolecule or tolerate it during ***-driven pathways signal downstream to complex networks,which regulate the balance between survival and death,and are collectively referred to as the DNA damage response(DDR).The classical DNA repair and DDR pathways have been elucidated in detail and a tight entanglement has been uncovered between ATM-ATR-DNA-PK driven pathways,chromatin remodeling,damage recruiting factors,and mechanisms removing or tolerating DNA damage in a simple(damage reversal)or more complex way(Fig.1).

关键词： networks damage removing

Surface chemistry of nanoscale Fe_3O_4 dispersed in magnetic fluids

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Science China Chemistry 2007年第6期50卷 754-758页

作者： bernd GüNTHER Fraunhofer Institut für Fertigungstechnik und Angewandte Materialforschung D-28359 Bremen Germany

The interaction between stabilizers and nanoparticles is one of the important factors to prepare stable magnetic fluids. The magnetic nano-size Fe3O4 core with single domain and the average grain size around 8-12 nm were prepared by chemical precipitation method. The O/Fe molar ratio of the particle surface was measured by X-ray photoelectron spectroscopy (XPS). The heat effects of stabilizers ad- sorption on nanoparticles were measured by solution calorimetry. The excess amount of oxygen was possibly the result of the hydroxygen formed on the surface of the nanoparticles. The heat effects showed that compounds containing carboxyl groups can be adsorbed chemically on magnetite by forming chemical bonds. The other stabilizers involving NH-groups, such as polyethylene-imine, can be adsorbed physically. The exothermic value is about half of the former case.

关键词： nanoscale materials heat effect magnetic fluids surface chemistry

Identification of digital technologies and digitalisation trends in the mining industry

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International Journal of Mining Science and Technology 2020年第6期30卷 747-757页

作者： Lars Barnewold bernd G.Lottermoser Institute of Mineral Resources Engineering RWTH Aachen University52062 AachenGermany

Digitalisation in mining refers to the use of computerised or digital devices or systems and digitised data that are to reduce costs,improve business productivity,and transform mining ***,it remains increasingly difficult for mining companies to decide which digital technologies are most relevant to their needs and individual *** paper provides an overview of digital technologies currently relevant to mining companies as presented and discussed by mining journals,the media and insight reports of leading consultancy *** technologies were systematically identified using text-mining techniques,and network analyses established the relations between significant *** demonstrated that currently 107 different digital technologies are pursued in the mining ***,an analysis of the actual implementation of digital technologies in 158 active surface and underground mines reveals a limited uptake of digital technologies in general and that the uptake increases with the run-of-mine ***-scale mining operations appear to select and apply digital technologies suitable to their needs,whereas operations with lower production rates do not implement the currently available digital technologies to the same *** minor producers may require other digital transformation solutions tailored to their capabilities and needs and applicable to their scale of operations.

关键词： Diffusion of digital technologies Automation Internet of things Big data Machine learning Artificial intelligence

A STUDY ON GRADIENT BLOW UP FOR VISCOSITY SOLUTIONS OF FULLY NONLINEAR,UNIFORMLY ELLIPTIC EQUATIONS

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Acta Mathematica Scientia 2012年第1期32卷 15-40页

作者： bernd Kawohl Nikolai Kutev Mathematisches Institut Universitt zu Kln Institute of Mathematics Bulgarian Academy of ScienceAcad.G.

We investigate sharp conditions for boundary and interior gradient estimates of continuous viscosity solutions to fully nonlinear, uniformly elliptic equations under Dirichlet boundary conditions. When these conditions are violated, there can be blow up of the gradient in the interior or on the boundary of the domain. In particular we de- rive sharp results on local and global Lipschitz continuity of continuous viscosity solutions under more general growth conditions than before. Lipschitz regularity near the boundary allows us to predict when the Dirichlet condition is satisfied in a classical and not just in a viscosity sense, where detachment can occur. Another consequence is this： if interior gra- dient blow up occurs, Perron-type solutions can in general become discontinuous, so that the Dirichlet problem can become unsolvable in the class of continuous viscosity solutions.

关键词： fully nonlinear elliptic equations viscosity solutions gradient estimates gra-dient blow up