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微米颗粒撞击液滴表面动力学行为特性研究
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作者 谢俊 赵冰姿 +2 位作者 李晨曦 付峥 李润东 《大连理工大学学报》 CAS CSCD 北大核心 2024年第2期138-147,共10页
颗粒撞击液滴表面的过程广泛存在于日常生活和工业生产中,且国内外对微米颗粒撞击液滴表面过程的研究较少,因此采用数值计算法对微米颗粒撞击液滴表面的行为进行了研究.建立了颗粒撞击液滴表面的动力学模型,对颗粒的撞击过程进行研究,... 颗粒撞击液滴表面的过程广泛存在于日常生活和工业生产中,且国内外对微米颗粒撞击液滴表面过程的研究较少,因此采用数值计算法对微米颗粒撞击液滴表面的行为进行了研究.建立了颗粒撞击液滴表面的动力学模型,对颗粒的撞击过程进行研究,深入分析了不同初始撞击速度下,撞击过程中颗粒受力、位移和三相接触角的变化情况.研究发现,颗粒在撞击液滴表面的过程中,表面张力和形状阻力是最主要的作用力.对于10μm颗粒,沉没和反弹之间的临界速度为9.080 m/s,反弹和振荡之间的临界速度为1.323 m/s,在沉没过程中,主导作用力由形状阻力变为表面张力.在反弹和振荡过程中,其运动分为下沉和回弹两部分.下沉过程中,主导作用力由形状阻力变为表面张力;回弹过程中,主导作用力先由表面张力变为形状阻力,然后又变回表面张力.初始撞击速度越大,颗粒在撞击过程中受到的作用力越强,速度、位移和三相接触角的变化速度越快,颗粒越容易沉没到液滴之中. 展开更多
关键词 颗粒 撞击 表面 表面张力 形状阻力
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基于表面力模型的液滴冲击弹性基底SPH模拟 被引量:1
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作者 董祥伟 李静 +1 位作者 黄小平 刘建林 《计算力学学报》 EI CAS CSCD 北大核心 2020年第4期486-495,共10页
采用光滑粒子动力学SPH方法建立液滴冲击弹性基底的流固耦合数值模型,给出描述粘性流体和弹性固体运动的SPH离散方程和数值处理格式,引入人工耗散项来抑制标准SPH方法的数值震荡。为模拟液滴的表面张力效应,通过精确检测边界粒子,采用... 采用光滑粒子动力学SPH方法建立液滴冲击弹性基底的流固耦合数值模型,给出描述粘性流体和弹性固体运动的SPH离散方程和数值处理格式,引入人工耗散项来抑制标准SPH方法的数值震荡。为模拟液滴的表面张力效应,通过精确检测边界粒子,采用拉格朗日插值方法计算表面法向量和曲率,结合界面理论中的连续表面力CSF方法,建立了适用于自由表面液滴的表面力模型,方形液滴变形的模拟结果与拉普拉斯理论解吻合较好。随后,采用SPH流固耦合模型模拟1.0 mm直径水滴以不同速度(0.2 m/s^3.0 m/s)冲击两种薄板型基底,分析了基底弹性变形对液滴铺展、收缩以及回弹行为的影响。 展开更多
关键词 SPH数值算法 自由表面液滴 流固耦合 弹性基底
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采用液滴萃取表面分析-串联质谱法检测真武汤中有效成分在心力衰竭模型大鼠体内的分布 被引量:9
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作者 仇琪 曹景琳 +2 位作者 郝晓艳 张芸楠 林阳 《中国医药》 2020年第2期207-211,共5页
目的采用液滴萃取表面分析-串联质谱法(LESA-MS/MS)对真武汤中有效成分进行检测,初步探讨真武汤对心力衰竭模型大鼠的治疗作用及其有效成分在模型大鼠体内的分布。方法雄性SD大鼠40只,采用冠状动脉左前降支结扎的方式制备心肌梗死后心... 目的采用液滴萃取表面分析-串联质谱法(LESA-MS/MS)对真武汤中有效成分进行检测,初步探讨真武汤对心力衰竭模型大鼠的治疗作用及其有效成分在模型大鼠体内的分布。方法雄性SD大鼠40只,采用冠状动脉左前降支结扎的方式制备心肌梗死后心力衰竭模型30只;另制作假手术动物10只(假手术组),只穿线不结扎。成功造模的大鼠(20只)完全随机分为模型对照组和真武汤组,每组10只。术后当天开始给药,真武汤组以羧甲基纤维素钠溶解方式灌胃给予真武汤粉剂,假手术组和模型对照组灌胃给予同体积羧甲基纤维素钠,连续给药60 d。其后对大鼠进行超声心动图检测。取大鼠心脏边缘区、肝脏和肾脏组织制备冰冻切片,通过LESA-MS/MS测定真武汤成分(茯苓酸、次乌头碱、去甲乌药碱)在不同组织中的分布。结果给药60 d后,模型对照组和真武汤组的左心室射血分数(LVEF)和左心室短轴缩短率(FS)均明显低于假手术组[(0.28±0.13)%、(0.39±0.08)%比(0.67±0.04)%,(0.27±0.02)%、(0.36±0.07)%比(0.50±0.03)%](均P<0.01);真武汤组的LVEF和FS均明显高于模型对照组(均P<0.05)。LESA-MS/MS结果显示,与模型对照组比较,真武汤组茯苓酸、次乌头碱和去甲乌药碱在大鼠心脏边缘区、肝脏、肾脏组织中的信号强度均明显增加(均P<0.01);真武汤有效成分在以上组织中的信号强度均为:去甲乌药碱>茯苓酸>次乌头碱。结论真武汤对心力衰竭大鼠的心功能有明显改善作用。真武汤的有效成分茯苓酸、次乌头碱和去甲乌药碱在心力衰竭大鼠的心脏边缘区、肝脏和肾脏均有分布,与中药理论中附子的归心、肾经和茯苓归心、肝经的记载相印证。心主血脉,肾主水,肝主疏泄,提示真武汤有效成分发挥作用可能与水液代谢相关。 展开更多
关键词 心力衰竭 真武汤 萃取表面分析 心功能 体内分布
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考虑结壳现象的液滴干燥过程数值模拟 被引量:1
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作者 张丽丽 周慎杰 史岩彬 《化学工程》 EI CAS CSCD 北大核心 2008年第12期10-13,共4页
为更清楚地了解液滴的干燥过程,文中综合考虑溶剂扩散系数与溶液质量分数,溶液质量分数与液滴表面蒸汽压和滴径变化与传热传质之间的耦合关系,建立了包含液滴内部径向热传导方程,液滴内部的传质方程及液滴质量变化方程的液滴蒸发的完整... 为更清楚地了解液滴的干燥过程,文中综合考虑溶剂扩散系数与溶液质量分数,溶液质量分数与液滴表面蒸汽压和滴径变化与传热传质之间的耦合关系,建立了包含液滴内部径向热传导方程,液滴内部的传质方程及液滴质量变化方程的液滴蒸发的完整模型。用所建模型对不同操作工况下液滴的挥发过程进行了模拟,描述了干燥过程中液滴质量损失,滴径的变化及液滴表面到中心的溶液组分变化,并对影响液滴干燥速度的重要因素进行了分析。模型模拟结果跟实验结论比较一致。 展开更多
关键词 扩散系数 质量分数 表面蒸汽压 径变化 传热传质 耦合 蒸发
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功能层负偏压对AlCrN/TiSiN多层涂层力学性能的影响
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作者 梁小彪 陈亚奋 张家权 《工具技术》 北大核心 2024年第9期42-46,共5页
通过电弧离子镀和高功率脉冲磁控溅射复合技术制备了功能层负偏压为40V,80V,120V和150V的多层AlCrN/TiSiN复合纳米涂层,通过SEM观察表面液滴,测量涂层硬度、结合力和应力,并进行切削测试,以此探究功能层负偏压变化对涂层性能的影响。测... 通过电弧离子镀和高功率脉冲磁控溅射复合技术制备了功能层负偏压为40V,80V,120V和150V的多层AlCrN/TiSiN复合纳米涂层,通过SEM观察表面液滴,测量涂层硬度、结合力和应力,并进行切削测试,以此探究功能层负偏压变化对涂层性能的影响。测量结果表明,随着功能层负偏压的升高,涂层的液滴数量先减少后增加,硬度和结合力先升高后降低,硬度和结合力在120V时达到最大,分别为34.6GPa和117.5N,内应力随功能层负偏压的升高而升高。切削测试结果显示,功能层负偏压在120V时刀具达到8h的最长寿命。 展开更多
关键词 功能层负偏压 表面液滴 纳米硬度 结合力 切削性能
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基于异形微结构表面的低表面能工质液滴润湿特性研究
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作者 王小伟 贾力 +1 位作者 李昊 党超 《工程热物理学报》 EI CAS CSCD 北大核心 2023年第7期1897-1903,共7页
尺寸效应是探索异形微结构表面液滴润湿特性的研究基础。本文以单凹角异形微结构和双凹角异形微结构为研究对象,通过数值模拟,得到了微结构的几何参数尺寸与低表面能液滴润湿特性间的变化规律。对于单凹角异形微结构,临界本征接触角随... 尺寸效应是探索异形微结构表面液滴润湿特性的研究基础。本文以单凹角异形微结构和双凹角异形微结构为研究对象,通过数值模拟,得到了微结构的几何参数尺寸与低表面能液滴润湿特性间的变化规律。对于单凹角异形微结构,临界本征接触角随着悬臂长度减小呈指数增加,微结构间的间距直接影响着表观接触角的大小,悬臂高度的增加不利于疏液状态的实现。对于双凹角异形微结构,悬臂长度和悬臂高度不是影响液滴润湿的主要因素,微结构间的间距和支柱高度共同作用下决定了液滴润湿状态。 展开更多
关键词 尺寸效应 异形微结构 表面 润湿状态
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基于气液相界面捕捉的统一气体动理学格式 被引量:5
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作者 王昭 严红 《力学学报》 EI CSCD 北大核心 2018年第4期711-721,共11页
气液相界面运动的研究无论是在科学还是工程领域都是非常重要的.其中,非平衡流动的计算尤其受到关注.基于此,我们构造了捕捉气液相界面的统一气体动理学格式.由于统一气体动理学格式将自由输运和粒子碰撞耦合起来更新宏观物理量和微观... 气液相界面运动的研究无论是在科学还是工程领域都是非常重要的.其中,非平衡流动的计算尤其受到关注.基于此,我们构造了捕捉气液相界面的统一气体动理学格式.由于统一气体动理学格式将自由输运和粒子碰撞耦合起来更新宏观物理量和微观分布函数,故而可以求解非平衡流动.具体思路是,通过将范德瓦尔斯状态方程所表达的非理想气体效应引入统一气体动理学格式之中来捕捉气液相界面,两相的分离与共存通过范德瓦尔斯状态方程描述.由于流体在椭圆区域是不稳定的,因此气液相界面可以通过蒸发和凝结过程自动捕捉.如此,一个锋锐的相界面便可以通过数值耗散和相变而得到.利用该方法得到麦克斯韦等面积律(Maxwell construction)对应的数值解,并与其相应的理论解相比较,二者符合良好.而后,通过对范德瓦尔斯状态方程所描述的液滴表面张力进行数值计算,验证了Laplace定理.此外,通过模拟两个液滴的碰撞融合过程,进一步证明了该格式的有效性.但是,由于范德瓦尔斯状态方程的特性,其所构造的格式仅适用于液/气两相密度比小于5的情况. 展开更多
关键词 统一气体动理学格式 范德瓦尔斯状态方程 相界面捕捉 麦克斯韦等面积律 表面张力
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液滴撞击固体表面铺展特性的实验研究 被引量:48
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作者 毕菲菲 郭亚丽 +2 位作者 沈胜强 陈觉先 李熠桥 《物理学报》 SCIE EI CAS CSCD 北大核心 2012年第18期295-300,共6页
利用高速摄影仪记录了不同液滴撞击固体表面的形态变化过程,并探讨了液滴撞击参数对撞击过程液滴形态的影响.结果表明:液滴黏度对液滴铺展过程起着决定性作用,液滴表面张力对液滴铺展后的回缩起到主导作用,两者的共同作用决定着液滴的... 利用高速摄影仪记录了不同液滴撞击固体表面的形态变化过程,并探讨了液滴撞击参数对撞击过程液滴形态的影响.结果表明:液滴黏度对液滴铺展过程起着决定性作用,液滴表面张力对液滴铺展后的回缩起到主导作用,两者的共同作用决定着液滴的震荡特性;撞击速度的提高会增大液滴的最大铺展因子,但达到最大铺展的时间因表面张力的不同呈现不同变化规律. 展开更多
关键词 撞击 铺展 表面张力
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液滴萃取表面分析-质谱法用于新鲜与蒸制三七根切片中皂苷成分的快速鉴别 被引量:4
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作者 田妹 李林楠 +2 位作者 杨远贵 杨莉 王峥涛 《药学学报》 CAS CSCD 北大核心 2020年第1期123-130,共8页
三七为五加科植物三七(Panax notoginseng)的干燥根及根茎,为我国传统珍贵中药材,具有止血散瘀、消肿止痛等功效。相比于新鲜三七,蒸制三七对治疗肿瘤和心血管疾病等表现出更好的疗效。皂苷是三七主要的化学和药效成分,本研究基于表面... 三七为五加科植物三七(Panax notoginseng)的干燥根及根茎,为我国传统珍贵中药材,具有止血散瘀、消肿止痛等功效。相比于新鲜三七,蒸制三七对治疗肿瘤和心血管疾病等表现出更好的疗效。皂苷是三七主要的化学和药效成分,本研究基于表面萃取结合芯片多通道纳喷质谱技术,建立了液滴萃取表面分析-质谱方法 (LESAMS),能够直接、快速地对新鲜与蒸制三七根切片中木质部、韧皮部和形成层中皂苷成分进行鉴别。实验结果表明,新鲜与蒸制三七根中皂苷成分及其含量具有一定的差异,表现为在新鲜三七根切片中,人参皂苷Rg1、Rb1、Re、Rd,三七皂苷R1及其丙二酰类成分较高。而在蒸制三七根切片中,人参皂苷Rg5、Rk1等弱极性成分能被检测到,大极性成分则相对含量较低。本方法具有快速、稳健且灵敏度高的优势,且操作过程无需破碎、萃取、色谱分离等繁琐的步骤,实现了对鲜三七与蒸三七根切片所含化学成分及二者差异的无损分析。 展开更多
关键词 萃取表面分析 质谱 三七 皂苷 快速鉴别
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油浸绝缘纸局部放电损伤产物分析 被引量:13
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作者 严家明 廖瑞金 +2 位作者 杨丽君 郝建 孙才新 《电工技术学报》 EI CSCD 北大核心 2011年第5期184-191,198,共9页
文章对局部放电损伤过程中油浸绝缘纸的表面生成物及气隙气体进行了分析。利用显微镜和扫描电镜分析了绝缘表面形貌;利用红外光谱仪和X射线光电子能谱仪研究了绝缘表面生成物及其组分;同时分析了气隙气体体积变化,并利用气质联动仪研究... 文章对局部放电损伤过程中油浸绝缘纸的表面生成物及气隙气体进行了分析。利用显微镜和扫描电镜分析了绝缘表面形貌;利用红外光谱仪和X射线光电子能谱仪研究了绝缘表面生成物及其组分;同时分析了气隙气体体积变化,并利用气质联动仪研究了气体组分及其含量。研究结果表明:局部放电损伤过程中,气隙气体体积和电负性气体含量交替下降上升,放电形式在脉冲放电和亚辉光(或辉光)放电之间交替转换;绝缘表面相继出现"表面液滴"和"晶状固体","表面液滴"主要为含C=O基团化合物,"晶状固体"主要为羧酸类物质,同时纤维素链中也有羧基生成;表面产物主要是裂解产物在局部放电作用下逐渐氧化的结果。 展开更多
关键词 局部放电 油浸绝缘纸 损伤 表面液滴 晶状固体 电负性气体
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低表面张力液滴类超疏悬浮状态实验 被引量:1
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作者 刘鑫源 贾力 +2 位作者 徐金柱 党超 丁艺 《科学通报》 EI CAS CSCD 北大核心 2021年第30期3916-3924,共9页
低表面能工质被广泛应用于各种工业和先进技术领域,如制冷剂喷雾冷却和微流控系统等,其润湿性和动力学行为的有效调控对提高分析过程的效率具有非常重要的作用.本文利用表面规则微孔的气流作用,调控低表面张力液滴的润湿行为,形成类超... 低表面能工质被广泛应用于各种工业和先进技术领域,如制冷剂喷雾冷却和微流控系统等,其润湿性和动力学行为的有效调控对提高分析过程的效率具有非常重要的作用.本文利用表面规则微孔的气流作用,调控低表面张力液滴的润湿行为,形成类超疏悬浮状态,并对该现象中液滴运动行为及润湿性变化规律开展研究.类超疏悬浮状态中,液滴的运动行为演变可以分为悬停、振荡、弹跳、脱离4个阶段,本文探究了弹跳阶段液滴重力势能与表面能之间的转换关系.类比Young’s方程,提出了类超疏悬浮状态中的类接触角概念,用于研究液滴不同阶段的润湿行为变化规律,分析了在惯性力和表面张力影响下液滴类接触角与韦伯数的关系. 展开更多
关键词 表面张力 类超疏悬浮状态 动力学行为 润湿性
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Transition of super-hydrophobic states of droplet on rough surface 被引量:2
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作者 叶霞 周明 +2 位作者 蒋大林 李健 蔡兰 《Journal of Central South University》 SCIE EI CAS 2010年第3期554-559,共6页
Twelve samples with periodic array square pillars microstructure were prepared on the silicon wafer by plasma etching techniques, on which space b of the square pillars increased from 5 to 60 μm. In order to study th... Twelve samples with periodic array square pillars microstructure were prepared on the silicon wafer by plasma etching techniques, on which space b of the square pillars increased from 5 to 60 μm. In order to study the effect ofb on the wettability of the rough surface, the effects of apparent contact angle (CA) and sliding angle (a) of the droplet on the rough surface were measured with the contact angle meter. The results show that the experimental values of CA well agree with the classical wetting theory and a decreases with the increase of b. Two drop shapes exist on the samples' surface, corresponding to the Cassie state and the Wenzel state respectively. The contact state in which a drop would settle depends typically on the size of b. On the role of gravitation, the irreversible transition of a drop from Cassie state to Wenzel state should occur at a certain space of the square pillars. Since the transition has implications on the application of super-hydrophobic rough surfaces, theoretically, the prediction of wetting state transition on square pillar array micro-structured surfaces provides an intuitionistic guidance for the design of steady superhydrophobic surfaces. 展开更多
关键词 square pillar microstructure wetting mode transition apparent contact angle sliding angle
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Unsteady Motion of a Single Droplet in Surfactant Solutions 被引量:2
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作者 李晓锦 毛在砂 费维扬 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第6期715-725,共11页
A numerical investigation of the unsteady motion of a deformed drop released freely in another quiescent liquid contaminated by surfactant is presented in this paper. The finite difference method was used to solve num... A numerical investigation of the unsteady motion of a deformed drop released freely in another quiescent liquid contaminated by surfactant is presented in this paper. The finite difference method was used to solve numerically the coupled time-dependent Navier-Stokes and convective-diffusion equations in a body-fitted orthogonal coordinate system. Numerical simulation was conducted on the experimental cases, in which MIBK drops with the size ranging from 1.24 mm to 1.97 mm rose and accelerated freely in pure water and in dilute sodium dodecyl sulphate (SDS) aqueous solution. The applicability of the numerical scheme was validated by the agreement between the simulation results and the experimental data. Both the numerical and experimental results showed that the velocitytime profile exhibited a maximum rising velocity for drops in SDS solutions, which was close to the terminal velocity in pure water, before it dropped down to a steady-state value. The effect of the sorption kinetics of surfactant on the accelerating motion was also evaluated. It is also suggested that introduction of virtual mass force into the formulation improved obviously the precision of numerical simulation of transient drop motion. 展开更多
关键词 SURFACTANT single drop unsteady motion sorption kinetics numerical simulation
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Investigation of droplet breakup in liquid–liquid dispersions by CFD–PBM simulations:The influence of the surfactant type 被引量:5
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作者 Dongyue Li Antonio Buffo +2 位作者 Wioletta Podgórska Daniele L.Marchisio Zhengming Gao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第10期1369-1380,共12页
The accurate prediction of the droplet size distribution(DSD)in liquid–liquid turbulent dispersions is of fundamental importance in many industrial applications and it requires suitable kernels in the population bala... The accurate prediction of the droplet size distribution(DSD)in liquid–liquid turbulent dispersions is of fundamental importance in many industrial applications and it requires suitable kernels in the population balance model.When a surfactant is included in liquid–liquid dispersions,the droplet breakup behavior will change as an effect of the reduction of the interfacial tension.Moreover,also the dynamic interfacial tension may be different with respect to the static,due to the fact that the surfactant may be easily desorbed from the droplet surface,generating additional disruptive stresses.In this work,the performance of five breakup kernels from the literature is assessed,to investigate their ability to predict the time evolution of the DSD and of the mean Sauter diameter,when different surfactants are employed.Simulations are performed with the Quadrature Method of Moments for the solution of the population balance model coupled with the two-fluid model implemented in the compressible Two Phase Euler Foam solver of the open-source computational fluid dynamics(CFD)code Open FOAM v.2.2.x.The time evolution of the mean Sauter diameter predicted by these kernels is validated against experimental data for six test cases referring to a stirred tank with different types of surfactants(Tween 20 and PVA 88%)at different concentrations operating under different stirrer rates.Our results show that for the dispersion containing Tween 20 additional stress is generated,the multifractal breakup kernel properly predicts the DSD evolution,whereas two other kernels predict too fast breakup of droplets covered by adsorbed PVA.Kernels derived originally for bubbles completely fail. 展开更多
关键词 Breakup Stirred tank Liquid–liquid dispersions Interfacial tension CFD–PBM
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SPH Modeling of Droplet Impact on Solid Boundary
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作者 李大鸣 白玲 +1 位作者 李玲玲 赵明宇 《Transactions of Tianjin University》 EI CAS 2014年第2期112-117,共6页
A droplet undergoes spreading,rebounding or splashing when it impacts solid boundary,which is a typical phenomenon of free surface flow that exists widely in modern industry.Smoothed particle hydrodynamics(SPH)method ... A droplet undergoes spreading,rebounding or splashing when it impacts solid boundary,which is a typical phenomenon of free surface flow that exists widely in modern industry.Smoothed particle hydrodynamics(SPH)method is applied to numerically study the dynamical behaviors of the droplet impacting solid boundary,and both the spreading and rebounding phenomena of the droplet are reproduced in the simulation.The droplet deformation,flow fields and pressure fields inside the droplet at different moments are analyzed.Two important factors,the initial velocity and diameter,are discussed in determining the maximum spreading factor,revealing that the maximum spreading factor increases with the increase of the impact velocity and droplet diameter respectively. 展开更多
关键词 SPH model droplet impact solid boundary maximum spreading factor
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建立同时检测大鼠组织中真武汤有效成分的LESA-MS/MS方法研究 被引量:7
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作者 仇琪 曹景琳 +2 位作者 张芸楠 李静 林阳 《中华中医药杂志》 CAS CSCD 北大核心 2020年第3期1476-1479,共4页
目的:建立同时检测大鼠组织中真武汤有效成分的表面液滴萃取-质谱联用(LESA-MS/MS)方法,为中药体内分布研究探索新的检测方法。方法:清洁级健康雄性SD大鼠40只,随机分为两组:正常对照组、真武汤组。真武汤组给予真武汤粉剂9.1g/kg,每日... 目的:建立同时检测大鼠组织中真武汤有效成分的表面液滴萃取-质谱联用(LESA-MS/MS)方法,为中药体内分布研究探索新的检测方法。方法:清洁级健康雄性SD大鼠40只,随机分为两组:正常对照组、真武汤组。真武汤组给予真武汤粉剂9.1g/kg,每日早晚各1次,均以0.5%羧甲基纤维素钠溶液灌胃给药,灌胃体积为10mL/kg,正常对照组大鼠根据体质量给予0.5%羧甲基纤维素钠溶液,连续灌胃给药60d。给药60d后取两组大鼠心脏、肾脏和肝脏组织制备冰冻切片。本研究以甲醇、水和氨水作为萃取溶液,采用LESA-MS/MS方法进行检测:通过工作站控制机器人在多重反应监测(MRM)模式下进行检测,负离子扫描模式,扫描范围120到1000Da,分辨率100000,采集时间2min。监测离子对:去甲乌药碱m/z 270.1→135.1,茯苓酸m/z 527.3→221.2,次乌头碱m/z 616.3→338.1。结果:稳定性考察显示,心脏、肾脏和肝脏组织中的待测物在反复复融3次后检测结果稳定,在-80℃冰箱中冷冻保存14d后检测结果稳定,在室温下放置24h后检测结果稳定。结论:本研究建立了同时测定大鼠组织中去甲乌药碱、茯苓酸和次乌头碱3种真武汤中有效成分的LESA-MS/MS分析方法。该方法样品前处理简单,省时省力,稳定性好,适于在临床医学领域推广和应用。 展开更多
关键词 表面液滴萃取-质谱联用 真武汤 有效成分 同时检测
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Rebound behaviors of droplets impacting on a superhydrophobic surface 被引量:4
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作者 HU HaiBao CHEN LiBin +1 位作者 HUANG SuHe SONG BaoWei 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第5期960-965,共6页
The rebound behaviors of droplets impacting on a self-fabricated superhydrophobic brass surface (WCA=I64.5°) were ob- served and studied by using high-speed-camera. In accordance with energy conversion, theoret... The rebound behaviors of droplets impacting on a self-fabricated superhydrophobic brass surface (WCA=I64.5°) were ob- served and studied by using high-speed-camera. In accordance with energy conversion, theoretical analysis of different behav- iors and rebound mechanism were given. At lower velocities, three behaviors in different velocity ranges were observed: par- tial rebounding, entire rebounding and ejecting during rebounding. At higher velocities, such two behaviors as rebound after splashing and rebound, ejecting after splashing, occurred alternately and exhibited certain periodicity. A function to predict the critical impact velocity is derived from energy conservation condition, and the prediction values tally with the experimental values, with the maximum relative error about 14%. 展开更多
关键词 SUPERHYDROPHOBIC droplets REBOUND critical impact velocity
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Numerical simulation of droplet impacting liquid surface by SPH 被引量:6
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作者 LI DaMing LI XiaoYu LIN Yi 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第7期1873-1880,共8页
Droplet impacting liquid surface is not only the extremely prevalent phenomenon in the nature and industrial production but also the extremely complicated problem of strong non-linear transient impact and free-surface... Droplet impacting liquid surface is not only the extremely prevalent phenomenon in the nature and industrial production but also the extremely complicated problem of strong non-linear transient impact and free-surface flow. On the basis of the two-dimensional viscous incompressible N-S equations, this paper conducts a study of numerical simulation on the problem of droplet impacting liquid surface (water beads) of water container in certain initial velocity by the method of SPH (smoothed particle hydrodynamics). The effect of surface tension is considered between surface particles by searching the free surface particles in the course of study; the effect of initial impact has been solved by use of artificial viscosity; at the same time, the side-wall virtual particles and image virtual particles are both introduced to deal with the boundary condition, which has solved the boundary defects quite well and eliminated the instability of real particles dropped to the comer of container. The calculated results form the distribution chart of particles, flow field chart, pressure chart and the displacement and velocity variation curve of different particles. The comparison between simulated results and experimental photos shows that the simulation is effective. This paper compares the variational curves for fluctuations of liquid surface qualitatively through adopting the methods of level-set, BEM and SPH, respectively at last. The simulated results show that it will produce strong non-linear phenomena, such as the splash of liquid, discrete liquid surface, and strong wave of free liquid surface, when the droplet impacts liquid surface; in the course of impacting, the movement of liquid particles exhibits the characteristic of oscillation; the method of SPH has certain advantages of dealing with the large deformation problem of free surface. 展开更多
关键词 SPH the process of droplet impact free surface numerical simulation
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Sessile droplet freezing and ice adhesion on aluminum with different surface wettability and surface temperature 被引量:1
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作者 OU JunFei SHI QingWen +4 位作者 WANG ZhiLe WANG FaJun XUE MingShan LI Wen YAN GuiLong 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第7期67-74,共8页
This paper focused on the sessile droplet freezing and ice adhesion on aluminum with different wettability (hydrophilic, com- mon hydrophobic, and superhydrophobic surfaces, coded as HIS, CHS, SHS, respectively) ove... This paper focused on the sessile droplet freezing and ice adhesion on aluminum with different wettability (hydrophilic, com- mon hydrophobic, and superhydrophobic surfaces, coded as HIS, CHS, SHS, respectively) over a surface temperature range of -9℃ to -19℃. It was found that SHS could retard the sessile droplet freezing and lower the ice adhesion probably due to the interfacial air pockets (IAPs) on water/SHS interface. However, as surface temperature decreasing, some IAPs were squeezed out and such freezing retarding and adhesion lowering effect for SHS was reduced greatly. For a surface temperature of-19℃, ice adhesion on SHS was even greater than that on CHS. To discover the reason for the squeezing out of lAPs, forces applied to the suspended water on IAPs were analyzed and it was found that the stability of IAPs was associated with surface mi- cro-structures and surface temperature. These findings might be helpful to designing of SHS with good anti-icing properties. 展开更多
关键词 SUPERHYDROPHOBIC ANTI-ICING ice adhesion interfacial air pockets
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Wetting transition energy curves for a droplet on a square-post patterned surface 被引量:3
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作者 Wei Gong Yingqing Zu +1 位作者 Sheng Chen Yuying Yan 《Science Bulletin》 SCIE EI CAS CSCD 2017年第2期136-142,共7页
Due to the property of water repellence, biomimetic superhydrophobic surfaces have been widely applied to green technologies, in turn inducing wider and deeper investigations on superhydrophobic surfaces. Theoretical,... Due to the property of water repellence, biomimetic superhydrophobic surfaces have been widely applied to green technologies, in turn inducing wider and deeper investigations on superhydrophobic surfaces. Theoretical, experimental and numerical studies on wetting transitions have been carried out by researchers, but the mechanism of wetting transitions between Cassie-Baxter state and Wenzel state, which is crucial to develop a stable superhydrophobic surface, is still not fully understood. In this paper, the flee energy curves based on the transition processes are presented and discussed in detail. The exis- tence of energy barriers with or without consideration of the gravity effect, and the irreversibility of wet- ting transition are discussed based on the presented energy curves. The energy curves show that different routes of the Cassie-to-Wenzel transition and the reverse transition are the main reason for the irre- versibility. Numerical simulations are implemented via a phase field lattice Boltzmann method of large density ratio, and the simulation results show good consistency with the theoretical analysis. 展开更多
关键词 Wetting transition Energy curves Lattice Boltzmann method
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