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Journal of Magnesium and Alloys 2021年第1期9卷 112-122页

作者： bjorn wiese Regine Willumeit-Römer Dietmar Letzig Jan Bohlen Division Metallic Biomaterials Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck-Str.1Geesthacht 21502Germany Magnesium Innovation Center(MagIC) Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck-Str.1Geesthacht 21502Germany

The effect of Ag in solid solution on the microstructure,texture and the deformation behaviour of indirectly extruded Mg was *** as a solid solution strengthener affects the behaviour during extrusion,resulting in enhanced deformation related heating and corresponding coarser grained *** substantial effect on the texture development is *** mechanical properties simultaneously increase in stress and strain levels with increasing Ag content,especially in tension as a result of the changing impact of the slip modes which can be associated with a decrease of the lattice parameters as well as the c/a ratio of the hcp lattice *** compression tests with twin dominated flow,the impact is much smaller on the compressive yield stress but higher with respect to the twinning related strain hardening *** solution strength functions for Fleischer and Labusch were determined,also confirming the anisotropic behaviour of the extruded Mg alloys.

关键词： Mg-Ag-alloys Lattice parameters Indirect extrusion Microstructure Mechanical properties

Pore characterization of PM Mg–0.6Ca alloy and its degradation behavior under physiological conditions

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Journal of Magnesium and Alloys 2021年第2期9卷 686-703页

作者： Eshwara Phani Shubhakar Nidadavolu Diana Krüger Berit Zeller-Plumhoff Domonkos Tolnai björn wiese Frank Feyerabend Thomas Ebel Regine Willumeit-Römer Division Metallic Biomaterials Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck-Str.1Geesthacht 21502Germany Magnesium Innovation Center(MagIC) Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck-Str.1Geesthacht 21502Germany

Several material parameters affect degradation characteristics of Mg and its alloys under physiological *** Mg materials are interesting for their simultaneous degradation and drug delivery ***,an increase in pore surface area is detrimental to both degradation resistance and subsequent mechanical *** present work aims at determining the threshold porosity value in Mg–0.6 Ca specimens produced by powder metallurgy(PM)below which low degradation rates persist with acceptable mechanical *** different porous Mg–0.6 Ca specimens containing both closed and open pore structures were fabricated with porosities ranging from 3%to 21%.Degradation profiles were obtained via a semi static immersion test over 16 days under physiological conditions using Dulbecco’s modified Eagle’s medium with Glutamax and 10%fetal bovine serum as *** results are related to morphological pore parameters like pore size distribution,pore interconnectivity and pore curvatures that were quantified using an ex situμCT *** general,with decreasing porosity a decrease in pore interconnectivity is seen followed by rounding of the *** degradation rates(MDR<0.3 mm/year)are observed in specimens until 10%porosity,however,the upper bound for reproducible degradation is observed to be in specimens until 12%*** porosity level also marks the transition from closed to open pore nature with a simultaneous change in pore interconnectivity from less than 10%to greater than 95%,below and above this porosity level,*** tensile strength and elongation to failure recorded for specimens with 10%porosity were 70 MPa and 2%,respectively displaying positive traits of both homogenous degradation and mechanical *** results suggest that high pore interconnectivity is the dominant factor controlling degradation and mechanical properties in porous Mg-0.6 Ca *** results also indicate a good sintering respons

关键词： Porous Mg-0.6Ca In vitro Degradation μCT Sintering

Assessing the microstructure and in vitro degradation behavior of Mg-xGd screw implants using μCT

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Journal of Magnesium and Alloys 2021年第6期9卷 2208-2223页

作者： Diana Krüger Berit Zeller-Plumhoff björn wiese Sangbong Yi Marcus Zuber D.C.Florian Wieland Julian Moosmann Regine Willumeit-Römer Institute of Metallic Biomaterials Helmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Institute of Material and Process Design Helmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Institute for Photon Science and Synchrotron Radiation Karlsruhe Institute of TechnologyHerrmann-von-Helmholtz-Platz 1Eggenstein-Leopoldshafen 76344Germany Laboratory for Applications of Synchrotron Radiation Karlsruhe Institute of TechnologyKaiserstr.12KarlsruheGermany Institute of Materials Physics Helmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany

Biodegradable implants are taking an increasingly important role in the area of orthopedic implants with the aim to replace permanent implants for temporary bone healing *** the implant preparation process,the material’s surface and microstructure are being changed by stresses induced by *** degradable metal implants need to be fully characterized in terms of the influence of machining on the resulting microstructure and corrosion *** this study,micro-computed tomography(μCT)is used for the quantification of the degradation rate of biodegradable *** our best knowledge,for the first time quantitative measures are introduced to describe the degradation homogeneity in *** information enables a prediction in terms of implant stability during the degradation in the *** magnesium gadolinium alloys,Mg-5Gd and Mg-10 Gd(all alloy compositions are given in weight%unless otherwise stated),in the shape of M2 headless screws have been investigated for their microstructure and their degradation performance up to 56 *** the microstructure investigations particular attention was paid to the localized deformation of the alloys,due to the machining *** vitro immersion testing was performed to assess the degradation performance quantified by subsequent weight loss and volume loss(usingμCT)*** differences were observed in the degree of screw’s near surface microstructure being influenced from machining,the degradation rates of both materials appeared to be suitable for application in orthopedic *** the degradation homogeneity point of view no obvious contrast was detected between both ***,the higher degradation depth ratios between the crests and roots of Mg-5Gd ratios may indicated a less homogeneous degradation of the screws of these alloys on contract to the ones made of Mg-10Gd *** to its lower degradation rates,its more homogeneous microstructure,its weaker texture

关键词： Magnesium alloys Biodegradable implant Degradation rate Degradation homogeneity Micro-comptued tomography

Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 516-529页

作者： Ting Chen Banglong Fu Junjun Shen Uceu F.H.R.Suhuddin björn wiese Yuanding Huang Min Wang Jorge F.dos Santos Jean Pierre Bergmann Benjamin Klusemann Solid State Materials Processing Institute of Material MechanicsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Functional Magnesium Materials Institute of Metallic BiomaterialsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong UniversityDongchuan Road 800Shanghai 200240China Applied Materials and Manufacturing Energy and Environment DivisionPacific Northwest National LaboratoryPO Box 999RichlandWA 99352USA Production Technology Group Technisiche Universität IlmenauGustav-Kirchhoff-Platz 2Ilmenau 98693Germany Institute for Production Technology and Systems Leuphana University of LüneburgUniversitätsallee 1Lüneburg 21335Germany

In order to obtain Mg alloys with fine microstructures and high mechanical performances,a novel friction-based processing method,name as“constrained friction processing(CFP)”,was *** CFP,defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were *** to the previous as-cast microstructure,the grain size was reduced from more than 1 mm to around 4μm within 3 s by a single process *** compressive yield strength was increased by 350%while the ultimate compressive strength by 53%.According to the established material flow behaviors by“tracer material”,the plastic material was transported by shear *** the base material to the rod,the material experienced three stages,*** by the tool,upward flow with additional tilt,followed by upward *** microstructural evolution was revealed by“stop-action”*** microstructural development at regions adjacent to the rod is mainly controlled by twinning,dynamic recrystallization(DRX)as well as particle stimulated nucleation,while that within the rod is related to DRX combined with grain growth.

关键词： Constrained friction processing Magnesium alloys Microstructure Mechanical properties Grain refinement Plastic deformation

Deteriorated corrosion performance of micro-alloyed Mg-Zn alloy after heat treatment and mechanical processing

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Journal of Materials Science & Technology 2021年第33期92卷 214-224页

作者： Yiming Jin Carsten Blawert Hong Yang bjorn wiese Jan Bohlen Di Mei Min Deng Frank Feyerabend Regine Willumeit Division of Metallic Biomaterials Helmholtz-Zentrum Geesthacht21502 GeesthachtGermany Southwest Technology and Engineering Research Institute 400039 ChongqingChina Magnesium Innovation Center Helmholtz-Zentrum Geesthacht21502 GeesthachtGermany State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing400044China National Engineering Research Center for Magnesium Alloys Chongqing University400044 ChongqingChina Faculty of Engineering Christian-Albrechts-Universität zu Kiel24143 KielGermany

The corrosion performances of the as-cast and solution-treated Mg-0.5Zn samples were investigated in 0.9%Na Cl solution and *** the electrochemical measurement results and corrosion morphology observations,it is found that the corrosion resistance of Mg-0.5Zn deteriorated with the extension of solution treatment *** main reason was the formation of Fe-Si precipitates with higher Fe concentrations during heat *** Fe-Si precipitates,especially the ones with high Fe contents influenced the corrosion initiation and propagation *** regard of corrosion performance,the solution-treated and then extruded sample was also performing not as good as the cast and then directly extruded sample.

关键词： Magnesium Alloy Internetallics SEM Inclusions Corrosion

Violent collisions can reveal hexadecapole deformation of nuclei

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Nuclear Science and Techniques 2024年第7期35卷 1-3页

作者： björn Schenke Physics Department Brookhaven National LaboratoryUptonNY 11973USA

A new observable in heavy ion collision experiments was identified to be sensitive to the hexadecapole deformation of the colliding *** deformation is difficult to measure in traditional nuclear electric transition measurements,as it is often overwhelmed by the nuclear quadrupole *** opens the door to gain new insight into nuclear structure with experiments that were designed to study hot and dense nuclear matter.

关键词： deformation collision insight

Norwegian oil and gas storage in rock caverns-Technology based on experience from hydropower development

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 479-486页

作者： bjørn Nilsen Department of Geoscience and Petroleum Norwegian University of Science and Technology(NTNU)TrondheimNorway

Underground storage in rock caverns is widely used in Norway for many different petroleum products,such as crude oil,fuel,propane and ***,the caverns for such storages are unlined,*** is ensured without using any steel lining or *** main basis for the storage technology originates from the extensive hydropower development in *** part of this activity,about 4500 km of tunnels and shafts have been excavated,and around 200 large powerhouse caverns have been *** hydropower tunnels are mainly unlined,with hydrostatic water pressure on unlined rock of up to 1000 *** of the projects also include air cushion chambers with volumes of up to 1×10^(5)m^(3)and air pressure up to 7.7 *** lessons which are valuable also for underground oil and gas storage have been learnt from these *** a storage project to become successful,systematic,well planned design and ground investigation procedures are *** main steps of the design procedure are first to define the optimum location of the project,and then to optimize orientation,shape/geometry and dimensions of caverns and *** part of the procedure,ground investigations have to be carried out at several steps integrated with the progress of *** investigation and design procedures,and the great significance of these for the project to become successful will be *** examples of oil and gas storage in unlined rock caverns are given,illustrating the relevancy of experience from high-pressure hydropower projects for planning and design of unlined caverns for oil and gas storage.

关键词： Underground storage Oil Gas Liquefied petroleum gas(LPG) Hydropower Air cushion chamber

Influence of amphiphilic structures on the stability of polyphenols with different hydrophobicity

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Science China Chemistry 2007年第1期50卷 121-126页

作者： Bergensthl bjrn Food Technology Center for Chemistry and Chemical EngineeringLund UniversityPO Box 124S-22100LundSweden

Autooxidation of five polyphenols representing range of different hydrophobicities(catechin gallate (CG),(-)catechin((-)C),epicatechin(EC),epigallocatechin gallate(EGCG)and epigallocatechin(EGC)) in three different aqueous solutions:molecular solution,micellar solution(Tween-20)and liposomal dispersion(soybean lecithin)was monitored by *** rate of oxidation of the five polyphenols was higher at pH 4.5 than at pH *** with the control,addition of Tween-20(micellar structure)and lecithin(liposomal structure)significantly decreased the degradation of *** the presence of lecithin the autooxidation of all the five polyphenols was slower than in the presence of Tween-20. The effective protection of the colloidal structures was compared with the hydrophobicity of the poly- phenols estimated from the partitioning between octanol and *** protection from oxidation in the presence of the colloidal structures(micellar or liposomal)increased with increasing partitioning of a polyphenol towards the hydrophobic *** protecting effect of the colloidal structures was more effective at pH 4.5 than at pH 3.5.

关键词： amphiphilic structures autooxidation polyphenols K value effective protection

Diagnosis and treatment of pancreatic exocrine insufficiency

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World Journal of Gastroenterology 2013年第42期19卷 7258-7266页

作者： bjrn Lindkvist Institute of Medicine Sahlgrenska AcademyUniversity of GothenburgSE-413 45 GothenburgSweden Division of Gastroenterology and Hepatology Department of Internal MedicineSahlgrenska University HospitalSE-413 45 GothenburgSweden

Pancreatic exocrine insufficiency is an important cause of maldigestion and a major complication in chronic *** digestion requires adequate stimulation of pancreatic secretion,sufficient production of digestive enzymes by pancreatic acinar cells,a pancreatic duct system without significant outflow obstruction and adequate mixing of the pancreatic juice with ingested *** in any of these steps may result in pancreatic exocrine insufficiency,which leads to steatorrhea,weight loss and malnutrition-related complications,such as *** evaluating digestion,such as fecal fat quantification and the13C-mixed triglycerides test,are the most accurate tests for pancreatic exocrine insufficiency,but the probability of the diagnosis can also be estimated based on symptoms,signs of malnutrition in blood tests,fecal elastase 1 levels and signs of morphologically severe chronic pancreatitis on *** for pancreatic exocrine insufficiency includes support to stop smoking and alcohol consumption,dietary consultation,enzyme replacement therapy and a structured follow-up of nutritional status and the effect of *** enzyme replacement therapy is administered in the form of enteric-coated minimicro-spheres during *** dose should be in proportion to the fat content of the meal,usually 40-50000 lipase units per main meal,and half the dose is required for a *** cases that do not respond to initial treatment,the doses can be doubled,and proton inhibitors can be added to the *** review focuses on current concepts of the diagnosis and treatment of pancreatic exocrine insufficiency.

关键词： Chronic pancreatitis Pancreatic exocrine insufficiency Pancreatic enzyme replacement therapy

Solanaceae pangenomes are coming of graphical age to bring heritability back

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aBIOTECH 2022年第4期3卷 233-236页

作者： björn Usadel Institute for Biological Data Science CEPLASHeinrich Heine UniversityDüsseldorfGermany IBG-4 Bioinformatics BioSCForschungszentrum JülichJülichGermany

Two recent articles describe a pangenome of potato and a graph-based pangenome for tomato,*** latter improves our understanding of the tomato genomics architecture even further and the use of this graph-based pangenom... 详细信息

关键词： Tomato Potato Pangenome Graph-based pangenome Heritability