搜索到2697篇“ MICRO-SCALE“的相关文章
微米尺度的规则拓扑结构对细胞和组织行为的影响
2024年
生物材料表面的物理性质,如拓扑结构,由于其易于加工和稳定的生物作用而受到广泛关注.虽然已有许多研究报道了材料表面拓扑结构与细胞的相互作用,但由于不同研究中使用的微结构和实验环境的多样性,生物材料表面不同微结构与细胞/组织行为之间的影响关系尚未得到很好的统一评价.在本研究中,我们设计了11种图案(三角形、矩形、圆形等),这些图案包含两种类型的形貌(微坑和微柱),这样一共得到22种表面拓扑结构.我们在体外和体内对这些微结构影响细胞和组织的生物作用进行了评估.我们的研究结果表明,由连续微坑形成的凹槽微结构促进细胞迁移效果相比其他微结构更强.其中,由三角形微坑组成的凹槽在体外对细胞迁移的促进作用最强.在大鼠皮下模型中,这种三角形微坑组成的凹槽结构减少了纤维组织的包封,促进了血管的形成.
王兴旺郑晗毅汪璟余红梅唐前傅国胜任科峰计剑于路
关键词:BIOMATERIALS
Investigation of micro-scale shear response of sand–rubber granule mixture in terms of particle shape and grain scale deformability effects
2024年
In this study,the effects of particle shape of rigid sand and soft rubber materials on macro-scale shear response were reasoned based on micro-scale parameters.For this purpose,first,the shape properties of three different sand and two different rubber samples were quantified using image processing techniques,and the contact model parameters were calibrated through physical experiments.The direct shear test was simulated in a two-dimensional discrete element software with realistic particle forms.The soft nature of rubber particles was reflected using body-centered cubic packing with a linear-parallel bond contact model.As a result,coordination number,distribution of contact forces(i.e.,strong contact,and fabric anisotropy),and contact sliding were derived by the numerical analyses.It has been observed that the particle shape leads to distinctive micro-scale responses due to the variations in the stiffness of the contacts.
Abdulmuttalip AriSuat Akbulut
关键词:SANDRUBBER
Coupled bio-chemo-hydro-mechanical modeling of microbially induced calcite precipitation process considering biomass encapsulation using a micro-scale relationship
2024年
Geomaterials with inferior hydraulic and strength characteristics often need improvement to enhance their engineering behaviors.Traditional ground improvement techniques require enormous mechanical effort or synthetic chemicals.Sustainable stabilization technique such as microbially induced calcite precipitation(MICP)utilizes bacterial metabolic processes to precipitate cementitious calcium carbonate.The reactive transport of biochemical species in the soil mass initiates the precipitation of biocement during the MICP process.The precipitated biocement alters the hydro-mechanical performance of the soil mass.Usually,the flow,deformation,and transport phenomena regulate the biocementation technique via coupled bio-chemo-hydro-mechanical(BCHM)processes.Among all,one crucial phenomenon controlling the precipitation mechanism is the encapsulation of biomass by calcium carbonate.Biomass encapsulation can potentially reduce the biochemical reaction rate and decelerate biocementation.Laboratory examination of the encapsulation process demands a thorough analysis of associated coupled effects.Despite this,a numerical model can assist in capturing the coupled processes influencing encapsulation during the MICP treatment.However,most numerical models did not consider biochemical reaction rate kinetics accounting for the influence of bacterial encapsulation.Given this,the current study developed a coupled BCHM model to evaluate the effect of encapsulation on the precipitated calcite content using a micro-scale semiempirical relationship.Firstly,the developed BCHM model was verified and validated using numerical and experimental observations of soil column tests.Later,the encapsulation phenomenon was investigated in the soil columns of variable maximum calcite crystal sizes.The results depict altered reaction rates due to the encapsulation phenomenon and an observable change in the precipitated calcite content for each maximum crystal size.Furthermore,the permeability and deformation of the soil mass were affected by the sim
Pavan Kumar BhukyaNandini AdlaDali Naidu Arnepalli
关键词:ENCAPSULATIONMICRO-SCALE
纳微尺度溶液体系的精确计算被引量:1
2024年
在纳微尺度上,分子性质、传质过程、化学反应等均与在宏观尺度表现不同.因此,近年来在生命科学、材料科学等领域对于纳微尺度下的液滴和溶液体系的研究蓬勃发展.采用计算模拟手段对相关体系的准确表征有助于揭示其在微观层面的分子机制,并为解开生命的奥秘、促进新材料的研发提供新的见解.本综述回顾了使用模拟方法,包括分子力场、量子化学方法以及结合机器学习等,研究此类体系的最新进展,重点关注纳微尺度下气液界面(包括空气/水、空气/溶液,以及大气/水)的溶液体系.此外,我们还对适用于纳微尺度溶液化学的计算模拟手段未来的发展进行了展望.
霍军张一健张开宇刘沛洪本坤董昊黎书华
关键词:气液界面液滴量子化学
Assessment of micro-scale heat exchangers efficiency using lattice Boltzmann method and design of experiments
2024年
The study is focused on the use of nanofluids in a micro-open tall cavity,which is a type of micro heat exchanger(MHE).The cavity is heated from the bottom sidewall in a sinusoidal pattern,and the effects of four input parameters(Ra,Ha,Kn,and Vf)on heat transfer and irreversibility are investigated using numerical simulations based on Lattice Boltzmann Method(LBM).The findings of the study suggest that the local heat transfer on the bottom sidewall is strongly influenced by Ra and Ha,while the surface distribution of entropy generation is mainly dependent on Kn.The study also shows that the optimization of the magnitude and wavelength of the sinusoidal temperature can improve both local heat transfer and surface distribution of entropy generation.The results of the study provide valuable insights into the design of micro heat exchangers and suggest that the optimization of micro-porous geometries using DOE could lead to increased energy efficiency.The study contributes to our understanding of the complex interactions between input parameters in micro heat exchangers and highlights the importance of considering multiple parameters in the design process.
Mokhtar FerhiSameh AbidiRidha DjebaliFateh Mebarek-Oudina
关键词:MHD
微量热泳动技术原理及实验条件优化
2024年
微量热泳动(MST)是一种用于检测分子相互作用的新兴生物物理技术,具有样品用量少、检测时间短及适用范围广等优势.然而,实际操作中会存在多种试验条件、因素,如目标分子的荧光标记、样品的质控、样品的浓度选择等,不仅会影响MST的数据质量,还可能导致亲和力测试结果偏离较大的情况.在简述MST技术原理的基础上,梳理了MST试验过程中需要重点注意的影响因素及试验条件.通过合理选择、优化,帮助实验人员获得真实、有效的MST试验数据及亲和力结果.
郭爽管祥辰
关键词:分子相互作用
微乳液化学驱油提高采收率微观可视化
2024年
化学驱技术在提高油田采收率方面起着重要作用,微乳液体系因其独特性能得到广泛的研究和应用。采用复配C5以下的醇作为助表面活性剂优选微乳液体系,通过微流控技术可视化分析微乳液驱油的动态驱替过程、剩余油形态和分布及驱油效果。首先优选助表面活性剂异丙醇和正丁醇的质量分数,再进一步优选NaCl的质量分数,最终结合微观可视化驱替实验选取最优配方。实验结果表明,固定油水两相比例1∶1、十二烷基硫酸钠(SDS)质量分数5%、8%正丁醇作为助剂、3%NaCl为最佳配方,最终采收率达98.8%;在高渗区剩余油饱和度为0.15%,低渗区剩余油饱和度为1.05%;NaCl可以通过改变水的极性降低界面张力;正丁醇作为助剂,因其独特性能,在微乳液驱油中与表面活性剂和NaCl协同可大幅度降低界面张力,改变芯片亲油性,促进油的剥离,大幅提高动用剩余油的能力。利用微流控技术研究微乳液原位乳化动态驱替过程为储层剩余油的高效开发提供了有效的理论指导和技术支撑。
朱哲涵何芬杨振航王辰于文强周毅
关键词:微乳液微流控芯片提高采收率可视化
航空模型燃料与氢气掺混微尺度燃烧数值模拟
2024年
对二维三级后台阶微燃烧器中以3种碳氢化合物(69%C_(10)H_(22)、11%C_(9)H_(18)、20%C_(9)H_(12))混合的Jet A-1模型燃料与氢气的掺混在纯氧中的燃烧进行了数值模拟,分析了燃料掺氢比、进气流速对微燃烧器内燃烧特性的影响。结果表明,所有火焰均可以稳定在微燃烧器第一后台阶(距离微燃烧器入口3 mm处)之前。随着掺氢比增加,火焰位置逐渐前移,火焰长度缩短,且微燃烧器内部的高温区面积减少,最高温度降低,上游燃烧强度更高但下游更低,CO和CH_(4)质量分数减小,裂解反应的发生位置前移且裂解产物的质量分数降低。随着入口进气流速增加,燃烧反应的高温区扩大,火焰中心位置和火焰前沿向微燃烧器出口移动和拉伸,掺氢比对壁面温度的影响减小,微燃烧器中心线OH质量分数整体增加,CO_(2)质量分数减小,CH_(4)质量分数增加,且裂解反应的发生位置后移且产物质量分数增加。结果表明:低速下可以掺混少量氢气得到更高的壁温从而获取更多能量。低速可能影响燃烧区燃料燃烧时的化学反应,从而造成上游的OH生成量减小。掺氢比的增加以及流速的降低会使CO质量分数波动更加明显。CO_(2)的质量分数最高时的掺氢比为25%。在高掺氢比和低进气流速下,乙炔大部分是靠燃料直接裂解生成,只有少量是通过丙烯的二次裂解生成。
陈星赫苏晟王娟
关键词:微尺度燃烧掺氢比燃烧特性裂解
A review on the synergism between corrosion and fatigue of magnesium alloys:Mechanisms and processes on the micro-scale
2024年
Understanding the interaction between cyclic stresses and corrosion of magnesium(Mg)and its alloys is increasingly in demand due to the continuous expansion of structural applications of these materials.This review is dedicated to exploring the corrosion-fatigue mechanisms of these materials,with an emphasis on microscale processes,and the possibility of expanding current knowledge on this topic using scanning electrochemical techniques.The interaction between fatigue and corrosion of Mg alloys is analyzed by considering the microstructural aspects(grain size,precipitates,deformation twins),as well as the formation of pits.Furthermore,in the case of coated alloys,the role of coating defects in these phenomena is also described.In this context,the feasibility of using scanning electrochemical microscopy(SECM),scanning vibrating electrode technique(SVET),scanning ion-selective electrode technique(SIET),localized electrochemical impedance spectroscopy(LEIS)and scanning Kelvin probe(SKP)methods to study the corrosion-fatigue interaction of Mg alloys is examined.A comprehensive review of the current literature in this field is presented,and the opportunities and limitations of consolidating the use of these techniques to study the microscale processes involved in Mg corrosion-fatigue are discussed.
Mara Cristina Lopes de OliveiraRejane Maria Pereira da SilvaRicardo M.SoutoRenato Altobelli Antunes
关键词:FATIGUE
重离子相对生物效应的双尺度模拟方法比较研究
2024年
重离子放射治疗是一种重要的癌症治疗手段,准确评估重离子的辐射生物效应对于提高粒子放疗的精细化水平具有重要意义。本研究基于双尺度剂量学方法和蒙特卡罗模拟,从宏观和微观两个尺度对^(12)C离子的相对生物效应(RBE)进行对比分析。本研究采用宏观的细胞存活线性平方模型(LQ)和微观的微剂量动力学模型(MKM)计算两个尺度的^(12)C离子RBE在体内的分布。蒙特卡罗模拟290 MeV/u的展宽^(12)C离子束在水模型内的宏观剂量及传能线密度(LET)分布,进而计算宏观^(12)C离子RBE。同时统计不同位置处体素内的粒子谱信息,并作为二次源项进行微剂量线能谱的模拟,进而计算微观尺度的^(12)C离子RBE。结果显示,10%细胞存活分数对应的物理剂量水平下,坪区两个尺度^(12)C离子RBE计算结果差异为16%,在布拉格峰处差异为25%。本研究提出了一种计算相同照射情况下宏观和微观两种尺度重离子RBE的模拟方法,并为重离子RBE模型的改进和临床应用提供参考。
胡子仪邱睿陈宜正胡安康武祯张辉张辉

相关作者

金钊
作品数:45被引量:399H指数:12
供职机构:中国科学院地球环境研究所
研究主题:黄土高原 土壤呼吸 淤地坝 人类活动影响 米槠
焦健
作品数:12被引量:10H指数:1
供职机构:清华大学
研究主题:微动 病毒 网络 网络病毒 雷达信号处理