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Numerical simulation of precipitation kinetics in multicomponent alloys

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journal of Materials Science & Technology 2022年第33期128卷 98-106页

作者： K.Xu j.D.Liu S.van der Zwaag W.Xu j.G.Li School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Novel Aerospace Materials Group Faculty of Aerospace EngineeringDelft University of TechnologyKluyverweg 12629 HSDelftThe Netherlands State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

A universal numerical model based on the particle size distribution(PSD)approach has been developed for the simulation of precipitation kinetics in multicomponent alloys during isothermal *** was implemented utilizing the classical nucleation theory(CNT).Growth and coarsening were modeled by a single growth kinetics equation,which is constructed based on the interfacial diffusion flux balance and the capillarity *** partial off-diagonal terms in the diffusion matrix(diffusion of individual components in the matrix)were taken into account in the calculations to minimize the computational cost while coupling with CALPHAD to extract thermodynamics equilibrium around the interface.A new feature of the model is the incorporation of a more realistic spatial site distribution via a Voronoi construction in the characteristic cell,for the purpose of modifying the diffusion *** predictions of the precipitate dimensions and the precipitation kinetics were compared with the atom probe tomography(APT)measurements on ternary Ni-Al-Cr alloys isothermally aged at 873 *** is found that the temporal evolution of the dimensions and composition of the precipitates is well captured,as is the dependence on changes in the alloy *** new modification with Voronoi construction demonstrates that the overall precipitation kinetics depends on the density and the spatial site distribution of *** ability to handle sophisticated alloy chemistries by quantitative equations,the compositional sensitivity of microstructural characteristics emerging from the simulation results,and the ability to visualize the spatial distribution of precipitates make the work very promising for multicomponent alloy design and optimization.

关键词： Precipitation kinetics Thermodynamics Multicomponent PSD Voronoi construction

Late Quaternary sinistral slip rate along the Altyn Tagh fault and its structural transformation model

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Science China Earth Sciences 2005年第3期48卷 384-397页

作者： P. Tapponnier j. van der Woerd F. j. Ryerson A.S. Meriaux Laboratoire de Tectonique Institut de Physique du Globe de Paris FranceLaboratoire de Tectonique Institut de Physique du Globe de Paris FranceIGPP Lawrence Livermore Laboratory Livermore CA 94550 USALaboratoire de Tectonique Institut de Physique du Globe de Paris France

Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic surfaces by using carbon fourteen (14C), cos- mogenic nuclides (10Be+26Al) and thermoluminescence (TL) methods, the Holocene sinistral slip rates on different segments of the Altyn Tagh Fault (ATF) are obtained. The slip rates reach 17.5 ±2 mm/a on the central and western segments west of Aksay Town, 11±3.5 mm/a on the Subei-Shibaocheng segment, 4.8±1.0 mm/a on the Sulehe segment and only 2.2±0.2 mm/a on the Kuantanshan segment, an easternmost segment of the ATF. The sudden change points for loss of sinistral slip rates are located at the Subei, Shibaocheng and Shulehe triple junctions where NW-trending active thrust faults splay from the ATF and propagate southeastward. Slip vector analyses indicate that the loss of the sinistral slip rates from west to east across a triple junction has structurally transformed into local crustal shortening perpendicular to the active thrust faults and strong uplifting of the thrust sheets to form the NW-trending Danghe Nanshan, Daxueshan and Qilianshan Ranges. Therefore, the eastward extrusion of the northern Qing- hai-Tibetan Plateau is limited and this is in accord with “the imbricated thrusting transforma- tion-limited extrusion model”.

关键词： Altyn Tagh Fault, sinistral strike-slip rate, structural transformation, extrusion tectonics.

Osteopontin increases hepatocellular carcinoma cell growth in a CD44 dependant manner

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World journal of Gastroenterology 2012年第26期18卷 3389-3399页

作者： Renee j Phillips Karla j Helbig Kylie H van der Hoek Devanshi Seth Michael R Beard School of Molecular and Biomedical Science The University of Adelaide5000 AdelaideAustralia Centre for Cancer Biology SA Pathology 5000 AdelaideAustralia Drug Health Services Royal Prince Alfred Hospital2050 CamperdownAustralia

AIM:To investigate the role of osteopontin(OPN) and its splice variants in the proliferation of hepatocellular carcinoma(HCC).METHODS:The expression of OPN variants in HCC cell lines as well as HCC tissue samples and nontumour tissue was studied using polymerase chain *** variant cDNAs were cloned into a mammalian expression vector allowing both transient expression and the production of stable OPN expressing cell *** expression was studied in these cells using Western blotting,immunofluoresnce and enzyme linked immunosorbent assay.A CD44 blocking antibody and siRNA targeting of CD44 were used to examine the role of this receptor in the OPN stimulated cell growth observed in ***-7 cells stably expressing either OPN-A,-B or-C were injected subcutaneously into the flanks of nude mice to observe in vivo tumour *** of OPN mRNA and protein in these tumours was examined using reverse transcriptionpolymerase chain reaction and ***:OPN is expressed in HCC in 3 forms,the full length OPN-A and 2 splice variants OPN-B *** variant expression was noted in HCC tissue as well as cognate surrounding cirrhotic liver *** of these OPN variants in the HCC derived cell line Huh-7 resulted in secretion of OPN into the culture *** of OPN conditioned media to na ve Huh-7 and HepG2 cells resulted in significant cell growth suggesting that all OPN variants can modulate cell proliferation in a paracrine *** the OPN mediated increase in cellular proliferation was dependent on CD44 as only CD44 positive cell lines responded to OPN conditioned media while siRNA knockdown of CD44 blocked the proliferative *** expression also increased the proliferation of Huh-7 cells in a subcutaneous nude mouse tumour model,with Huh-7 cells expressing OPN-A showing the greatest proliferative ***:This study demonstrates that OPN plays a significant role in the proliferation of HCC thro

关键词： Osteopontin Hepatocellular carcinoma CD44 antigen Nude mice Xenograft

Folded MoS2 layers with reduced interlayer coupling

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Nano Research 2014年第4期7卷 572-578页

作者： Andres Castellanos-Gomez Herre S. j. van der Zant Gary A. Steele Kavli Institute of Nanoscience Delft University of Technology 2528 CJ Delft The Netherlands

We study molybdenum disulfide （MoS2） structures generated by folding single-layer and bilayer MoS2 flakes. We find that this modified layer stacking leads to a decrease in the interlayer coupling and an enhancement of the photoluminescence emission yield. We additionally find that folded single-layer MoS2 structures show a contribution to photoluminescence spectra of both neutral and charged excitons, which is a characteristic feature of single-layer MoS2 that has not been observed in multilayer MoS2. The results presented here open the door to fabrication of multilayered MoS2 samples with high optical absorption while maintaining the advantageous enhanced photoluminescence emission of single-layer MoS2 by controllably twisting the MoS2 layers.

关键词： molybdenum disulfide(MoS2) folded MoS2 twisted MoS2 interlayer coupling Raman spectroscopy photoluminescence

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富蕴断裂:低应变速率条件下断层滑动习性

地震地质 2012年第4期34卷 606-617页

作者：徐锡伟孙鑫喆谭锡斌李康于贵华 Marie Etchebes Yann Klinger Paul Tapponnier j.van der Woerd 中国地震局地质研究所活动构造与火山重点实验室北京100029 Tectonics Institut de Physique du Globe de ParisSorbone Paris CitéCNRS Earth Observatory of Singapore Singapore Institut de Physique du Globe StrasbourgFrance

富蕴断裂是阿尔泰地区低应变速率条件下的典型右旋走滑断层之一。野外考察和3个观测点的3D陆地LiDAR扫描DEM影像断错地貌恢复、重建,结合高分辨率卫星影像解译等进一步证实,1931年富蕴地震同震右旋走滑位移平均值为(6.3±1.2)m,且沿富... 详细信息

富蕴断裂是阿尔泰地区低应变速率条件下的典型右旋走滑断层之一。野外考察和3个观测点的3D陆地LiDAR扫描DEM影像断错地貌恢复、重建,结合高分辨率卫星影像解译等进一步证实,1931年富蕴地震同震右旋走滑位移平均值为(6.3±1.2)m,且沿富蕴断裂向南北两端缓慢、平稳衰减,中部同震位移最大值为(6.7±0.5)m,而不是前人给出的10～14m;包含2～5次地震的同震累积位移值为1931年富蕴地震相同地点同震位移的整数倍,表明富蕴断裂大地震复发服从特征地震模型。2个观测点多级地貌面宇宙成因核素(10Be)系统测年数据,进一步限定富蕴断裂晚更新世以来的右旋走滑速率为(0.76±0.24)mm/a,大地震复发间隔(9700±3300)a。低滑动速率和长周期特征地震复发模型可能为板块间相互作用产生的远程应变效应的基本特征。

关键词：富蕴断裂同震右旋走滑位移特征地震复发模型阿尔泰地区

Dispersal of invasive species by drifting

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Current Zoology 2011年第6期57卷 818-827页

作者： M.C. van RIEL G. van der VELDE A. BIj DE VAATE Radboud University Nijmegen Institute for Water and Wetland Research Department of Animal Ecology and Ecophysiology Section Aquatic Animal Ecology Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands Team Freshwater Ecology DLO-Alterra P.O. Box 47 6700 AA Wageningen The Netherlands Netherlands Centre for Biodiversity Naturalis EO. Box 9517 2300 RA Leiden The Netherlands Waterfauna Hydrobiologisch Adviesbureau Oostrandpark 30 8212 AP Lelystad The Netherlands

Drifting can be an effective way for aquatic organisms to disperse and colonise new areas. Increasing connectivity between European large rivers facilitates invasion by drifting aquatic macroinvertebrates. The present study shows that high abundances of invasive species drift in the headstream of the river Rhine. Dikerogammarus villosus and Chelicorophium cur- vispinum represented up to 90% of the total of drifting macroinvertebrates. Drift activity shows seasonal and diel patterns. Most species started drifting in spring and were most abundant in the water column during the summer period. Drift activity was very low during the winter period. Diel patterns were apparent; most species, including D. villosus, drifted during the night. Drifting macroinvertebrates colonised stony substrate directly from the water column. D. villosus generally colonised the substrate at night, while higher numbers of C. curvispinum colonised the substrate during the day. It is very likely that drifting functions as a disper- sal mechanism for crustacean invaders. Once waterways are connected, these species are no longer necessarily dependent on dispersal vectors other than drift for extending their distribution range

关键词： Amphipods Invaders Colonization Drift Daily rhythms Seasonal variation

Postoperative surgical site infection in cholesteatoma surgery with and without mastoid obliteration, what can we learn?

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journal of Otology 2022年第1期17卷 25-30页

作者： F.L.j.Cals H.F.E.van der Toom R.M.Metselaar A.van Linge M.P.van der Schroeff R.j.Pauw Department of Otorhinolaryngology and Head and Neck Surgery Erasmus Medical CenterRotterdamthe Netherlands

Introduction:This study aims to describe the occurrence of postoperative complications related to cholesteatoma surgery and to determine factors influencing the most common complication,*** surgical site infection(SSI)in cases with and without mastoid *** and methods:Retrospective analyses were performed on surgically treated cholesteatomas in our hospital between 2013 and *** characteristics,peri-and postoperative management and complications were *** cases were divided into two groups based on whether mastoid obliteration was performed or ***:A total of 336 cholesteatoma operations were performed,of which 248 cases received mastoid *** total 21 complications were observed,of which SSI was the most common(15/21).No difference in occurrence of any postoperative complication was seen between the obliteration and noobliteration group(p=0.798),especially not in the number of SSI(p=0.520).Perioperative and/or postoperative prophylactic antibiotics were not associated to the development of an SSI in both *** the no-obliteration group a younger age(p=0.015),as well as primary surgery(p=0.022)increased the risk for *** the obliteration group the use of bioactive glass(BAG)S53P4 was identified as independent predictor of SSI(p=0.008,OR 5.940).Discussion:SSI is the most common postoperative complication in cholesteatoma *** causes of SSI are multifactorial,therefore further prospective research is needed to answer which factors can prevent the development of an SSI in cholesteatoma surgery.

关键词： Cholesteatoma Mastoid obliteration Postoperative surgical site infection Complications Bioactive glass S53P4

Osteoblast integration of dental implant materials after challenge by sub-gingival pathogens: a co-culture study in vitro

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International journal of Oral Science 2015年第4期7卷 250-258页

作者： Bingran Zhao Henny C van der Mei Minie Rustema-Abbing Henk j Busscher Yijin Ren Department of Orthodontics University of Groningen and University Medical Center Groningen Department of Biomedical Engineering University of Groningen and University Medical Center Groningen

Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium （Ti）, titanium-zirconium （TiZr） alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.

关键词： biofilm co-culture dental implant osteoblasts sub-gingival pathogens titanium-zirconium alloy

In vivo biofilm formation on stainless steel bonded retainers during different oral health-care regimens

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International journal of Oral Science 2015年第1期7卷 42-48页

作者： Marije A jongsma Henny C van der Mei jelly Atema-Smit Henk j Busscher Yijin Ren Department of Orthodontics University of Groningen and University Medical Centre Department of Biomedical Engineering University of Groningen and University Medical Centre

Retention wires permanently bonded to the anterior teeth are used after orthodontic treatment to prevent the teeth from relapsing to pre-treatment positions. A disadvantage of bonded retainers is biofilm accumulation on the wires, which produces a higher incidence of gingival recession, increased pocket depth and bleeding on probing. This study compares in vivo biofilm formation on single-strand and multi-strand retention wires with different oral health-care regimens. Two-centimetre wires were placed in brackets that were bonded to the buccal side of the first molars and second premolars in the upper arches of 22 volunteers. Volunteers used a selected toothpaste with or without the additional use of a mouthrinse containing essential oils. Brushing was performed manually. Regimens were maintained for 1 week, after which the wires were removed and the oral biofilm was collected to quantify the number of organisms and their viability, determine the microbial composition and visualize the bacteria by electron microscopy. A 6-week washout period was employed between regimens. Biofilm formation was reduced on single-strand wires compared with multi-strand wires; bacteria were observed to adhere between the strands. The use of antibacterial toothpastes marginally reduced the amount of biofilm on both wire types, but significantly reduced the viability of the biofilm organisms. Additional use of the mouthrinse did not result in significant changes in biofilm amount or viability. However, major shifts in biofilm composition were induced by combining a stannous fluoride- or triclosan-containing toothpaste with the mouthrinse. These shifts can be tentatively attributed to small changes in bacterial cell surface hydrophobicity after the adsorption of the toothpaste components, which stimulate bacterial adhesion to the hydrophobic oil, as illustrated for a Streptococcus mutans strain.

关键词： antimicrobials biofilm bonded retention wires mouthrinse orthodontics