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Cross-Linked Alginate Film Pore Size Determination Using Atomic Force Microscopy and Validation Using Diffusivity Determinations
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作者 Cheryl Simpliciano Larissa Clark +5 位作者 Behrokh Asi Nathan Chu Maria Mercado Steven Diaz Michel Goedert Maryam Mobed-Miremadi 《Journal of Surface Engineered Materials and Advanced Technology》 2013年第4期1-12,共12页
The deficit of organ donors has fueled the need for advances in tissue engineering and regenerative medicine. Microencapsulation in alginate immuno-isolation membranes has been used to treat many disabling metabolic d... The deficit of organ donors has fueled the need for advances in tissue engineering and regenerative medicine. Microencapsulation in alginate immuno-isolation membranes has been used to treat many disabling metabolic disorders, namely, phenylketonuria, kidney failure and diabetes mellitus. Systematic nutrient flux determinations are hindered by the lack of experimental data on alginate-based membrane topography and the pore size thus preventing the full therapeutic potential of the bio-membranes to be reached. In this study, samples of cross-linked alginate membranes were subjected to the following analytical characterization: 1) pore size characterization using atomic force microscopy operated in contact mode to detect and measure pore size;2) differential scanning calorimetry to confirm biopolymer cross-linking;and 3) diffusivity measurements using spectrophotometry and fluorescence microscopy to confirm the presence of through pores and to calculate reflection coefficients. The pore sizes for the pre-clinical standard formulation of 1.5% (w/v) medium viscosity alginate cross-linked with 1.5% CaCl2 and 0.5% (w/v) alginate and chitosan cross-linked with 20% CaCl2 are 5.2 nm ± 0.9 nm and 7.0 nm ± 3.1 nm, respectively. An increase in the glass transition temperatures as a function of cross-linker concentration was observed. Diffusivity values obtained from the inward diffusivity of creatinine into macrocapsules (d = 1000 μm ± 75 μm) and the outward diffusivity of FITC dextrans from macrocapsules (d = 1000 μm ± 75 μm) and microcapsules (d = 40 μm ± 5 μm) were shown to correlate strongly (R2 = 0.9835) with the ratio of solute to pore sizes, confirming the presence of through pores. Reflection coefficients approaching and exceeding unity correlate with the lack of permeability of the membranes to MW markers that are 70 kDa and greater. 展开更多
关键词 ALGINATE atomic Force Microscopy Pore size Stokes’ Radius DIFFUSIVITY Cross-linking Differential Scanning CALORIMETRY Reflection Coefficient
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Size Effects for the Adsorption of Alkali Metal Atoms on the Si(001) Surface
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作者 NI Bi-Lian HU Jian-Ming +1 位作者 ZHAO Yong-Gang LI Yi 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第6期837-852,共16页
The adsorptions of a series of alkali metal (AM) atoms, Li, Na, K, Rb and Cs, on a Si(001)-2 × 2 surface at 0.25 monolayer coverage have been investigated systematically by means of density functional theory ... The adsorptions of a series of alkali metal (AM) atoms, Li, Na, K, Rb and Cs, on a Si(001)-2 × 2 surface at 0.25 monolayer coverage have been investigated systematically by means of density functional theory calculations. The effects of the size of AM atoms on the Si(001) surface are focused in the present work by examining the most stable adsorption site, diffusion path, band structure, charge transfer, and the change of work function for different adsorbates. Our results suggest that, when the interactions among AM atoms are neglectable, these AM atoms can be divided into three classes. For Li and Na atoms, they show unique site preferences, and correspond to the strongest and weakest AM-Si interactions, respectively. In particular, the band structure calculation indicates that the nature of Li-Si interaction differs significantly from others. For the adsorptions of other AM atoms with larger size (namely, K, Rb and Cs), the similarities in the atomic and electronic structures are observed, implying that the atom size has little influence on the adsorption behavior for these large AM atoms on the Si(001) surface. 展开更多
关键词 size effects ADSORPTION alkali metal atoms Si(001) surface
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一种紧凑型微雾喷嘴雾化特性的试验研究
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作者 闫锦东 陈华 +1 位作者 周睿 程文龙 《流体机械》 北大核心 2026年第1期1-9,共9页
针对目前喷雾装置内部流道结构复杂、供液管路及接口多、占用空间大导致难以轻量化、紧凑化问题,提出基于入口流道、旋流腔和喷孔集成化的喷嘴结构设计理念,设计厚度5 mm的紧凑型微雾喷嘴,并搭建喷雾特性测量实验台,研究了紧凑型微雾喷... 针对目前喷雾装置内部流道结构复杂、供液管路及接口多、占用空间大导致难以轻量化、紧凑化问题,提出基于入口流道、旋流腔和喷孔集成化的喷嘴结构设计理念,设计厚度5 mm的紧凑型微雾喷嘴,并搭建喷雾特性测量实验台,研究了紧凑型微雾喷嘴几何结构参数对雾化特性影响的规律。研究表明,流量和雾化角受喷孔直径影响较大;增大旋流腔直径会减小液膜破碎长度,有利于实现更短距离内的一次雾化过程;在15 mm的喷雾高度,紧凑型微雾喷嘴轴向速度峰值均大于10 m/s,出现在喷雾锥内部;旋流腔直径较小时,喷雾中心处的液滴轴向速度占比最大;喷孔直径较大时,轴向速度占比沿径向衰减放缓;紧凑型微雾喷嘴的液滴索特平均粒径小于40μm,粒径和液滴数密度分布受旋流腔影响较小,喷孔直径的增大使得20μm以下粒径占比增加了25%。研究为实现雾化装置一体化、高度集成化设计提供了新的思路。 展开更多
关键词 紧凑型喷嘴 雾化特性 集成化设计 微雾雾化 粒径分布
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元素掺杂SmFe_(12)稀土合金铸锭的热力学分析
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作者 王婉婷 张紫辰 +3 位作者 柳昆 王书桓 冯运莉 温哥华 《中国冶金》 北大核心 2026年第2期161-167,181,共8页
通过采用合适的合金制备方法和元素掺杂调控合金铸锭的成分与组织结构、进而对金属材料进行改性,是改善SmFe_(12)系稀土合金中Sm元素易挥发、制备稳定性差、微观组织调控难等问题的重要手段。结合试验现象确定了感应熔炼法比电弧熔炼法... 通过采用合适的合金制备方法和元素掺杂调控合金铸锭的成分与组织结构、进而对金属材料进行改性,是改善SmFe_(12)系稀土合金中Sm元素易挥发、制备稳定性差、微观组织调控难等问题的重要手段。结合试验现象确定了感应熔炼法比电弧熔炼法更适合SmFe_(12)基稀土合金铸锭的制备。利用Zr、Co、Cu、Ti元素掺杂SmFe_(12)合金铸锭并将其在1100℃下进行36h的均匀化热处理,采用XRD和SEM对合金的相组成及微观组织进行表征分析,研究元素掺杂对合金相组成的影响机理。从混合焓、混合熵、吉布斯自由能及原子尺寸差等热力学参数角度对元素掺杂得到的效果进行分析。结合试验结果和热力学分析得出,SmFe_(12)合金铸锭稳定性差,难以制备,通过元素掺杂得以改善;在原子间作用力的作用下,Sm_(0.8)Zr_(0.2)Fe_(8.5)Co_(2)Cu_(0.5)Ti合金由SmFe_(11)Ti相、SmCu_(5)相和α-Fe相组成;Zr、Ti原子以固溶的形式存在于SmFe_(11)Ti相,且α-Fe相周围的SmFe_(11)Ti相中Zr、Ti的固溶度较高;在Cu原子对Sm原子的吸引力和对Fe、Co原子的排斥力的作用下,Cu元素以SmCu_(5)相的形式析出,促进了SmFe_(11)Ti相的分解,进而导致SmFe_(11)Ti相含量降低和α-Fe相含量升高。研究结果表明,Zr、Co、Cu、Ti元素的掺杂提高了SmFe_(12)基合金主相稳定性,同时析出了有望进一步优化合金磁性能的SmCu_(5)相,为今后的粉体制备提供了优质原料,调控SmCu_(5)相的晶粒尺寸及分布将成为新的研究方向。 展开更多
关键词 元素掺杂 稀土合金 相组成 热力学 原子尺寸差
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基于微孔雾化的禽舍免疫机器人精量喷雾控制方法
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作者 赵宇 宁泽婷 +4 位作者 李奇峰 魏一博 冯青春 高荣华 赵辉 《农业工程学报》 北大核心 2026年第2期105-113,共9页
针对传统禽舍压力雾化免疫方式存在噪声大、雾滴粒径分布不均及有效吸入率低等问题,该研究设计了一种基于压电微孔超声雾化的免疫机器人雾化部件,改善笼养禽舍喷雾免疫机器人作业效果。采用有限元仿真分析软件对雾化片进行多物理场耦合... 针对传统禽舍压力雾化免疫方式存在噪声大、雾滴粒径分布不均及有效吸入率低等问题,该研究设计了一种基于压电微孔超声雾化的免疫机器人雾化部件,改善笼养禽舍喷雾免疫机器人作业效果。采用有限元仿真分析软件对雾化片进行多物理场耦合建模,分析其振动模态与频率响应特性,确定最佳谐振频率113 kHz;提出了基于PI频率跟踪控制的精量喷雾控制方法,实现雾化片自身振动特性衰变的动态补偿。集成设计了模块化免疫雾化部件和禽舍喷雾免疫机器人系统,并开展了单喷嘴雾化试验以及免疫机器人应用验证。静态喷雾试验结果表明,距离免疫喷雾部件30~50 cm作业范围达到喷雾免疫要求粒径的雾滴数量占比90.81%,且相较于恒定频率驱动控制,采用频率跟踪精量雾化控制平均雾化效率提升1.57%。禽舍内机器人动态免疫喷雾作业过程中动态气流场促进雾滴聚合,雾滴平均粒径相较于静态喷雾增加42.81μm,总体达到免疫喷雾要求粒径的雾滴数量占比90.2%,满足禽舍喷雾免疫对雾滴粒径的要求,研究结果可为禽舍喷雾免疫机器人的研发和应用提供技术支撑。 展开更多
关键词 禽舍 免疫 喷雾 压电微孔雾化 谐振频率 频率跟踪控制 雾滴粒径
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植保机械分体式喷嘴材质与结构对雾化性能影响研究
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作者 曹胜瀚 邓建新 +2 位作者 戎世耀 包一琛 张志慧 《节水灌溉》 北大核心 2026年第3期1-6,共6页
传统一体化结构喷嘴存在参数固定、维护成本高的缺陷;分体式喷嘴通过可替换喷片实现结构参数灵活调节,其雾化性能直接由喷片决定。以空心锥形喷嘴为基体,通过控制单一变量探究喷片材料与结构参数对雾化质量的影响。结果表明:材料方面,YG... 传统一体化结构喷嘴存在参数固定、维护成本高的缺陷;分体式喷嘴通过可替换喷片实现结构参数灵活调节,其雾化性能直接由喷片决定。以空心锥形喷嘴为基体,通过控制单一变量探究喷片材料与结构参数对雾化质量的影响。结果表明:材料方面,YG6硬质合金喷片的性能优于304不锈钢及TiN涂层喷片;结构方面,雾化角随出口等径段长度减小而增大,随入口锥度增大而减小。当出口等径段长度为0.5 mm及以下、压力范围在0.2~0.5MPa时,雾滴体积中值直径保持在105~150μm,相对跨度因子均小于1.1,雾化效果细腻均匀。60°入口锥度喷片在0.5 MPa时可获得最大雾化角(64.28°),且其雾滴粒径和均匀性表现较好。推荐喷片采用YG6硬质合金材质配合0.5mm出口等径段长度及60°入口锥角组合,可同步实现雾化角最大化、粒径精细化与分布均匀化,为植保喷嘴精细化设计与精准施药提供直接选型依据。 展开更多
关键词 雾滴粒径 雾化角 喷嘴结构 雾化性能 植保机械 喷嘴材料
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水雾化法制备镍基自熔合金粉末工艺研究
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作者 李旺 张国锋 +3 位作者 张梦凡 李史星 孙朋 杨跃 《福建冶金》 2026年第2期22-25,共4页
本文采用水雾化工艺制备镍基自熔合金粉末,通过调整雾化工艺参数,研究了漏嘴直径、喷射顶角及雾化压力对粉末形貌、粒度分布、空心粉率等特性的影响。结果表明:在喷射顶角为32°、雾化压力为12 MPa、漏嘴直径为6 mm的条件下,制备的... 本文采用水雾化工艺制备镍基自熔合金粉末,通过调整雾化工艺参数,研究了漏嘴直径、喷射顶角及雾化压力对粉末形貌、粒度分布、空心粉率等特性的影响。结果表明:在喷射顶角为32°、雾化压力为12 MPa、漏嘴直径为6 mm的条件下,制备的合金粉末性能优异,松装密度为4.22 g/cm^(3),空心粉率25.8%,氧含量为0.032%,流动性为16.5 s/50 g,可满足螺杆、球阀表面喷焊用金属粉末的性能要求。 展开更多
关键词 水雾化 合金粉末 雾化参数 粒度分布 粉末形貌
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尘-雾最佳润湿粒径比确定及磁化活性水浸润煤尘机理研究
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作者 郝晋辉 王林芝 +2 位作者 宋军 葛少成 徐彬 《煤》 2026年第2期65-70,共6页
为增强湿式喷雾技术对微细煤尘的沉降效率,采用水磁化处理结合表面活性剂增效润湿技术,深入探究了磁化活性水对煤尘的润湿效果及降尘机制。首先,通过数值模拟确定了液滴捕集难浸润无烟煤尘的最佳润湿雾-尘粒径比,之后对最佳润湿粒径比... 为增强湿式喷雾技术对微细煤尘的沉降效率,采用水磁化处理结合表面活性剂增效润湿技术,深入探究了磁化活性水对煤尘的润湿效果及降尘机制。首先,通过数值模拟确定了液滴捕集难浸润无烟煤尘的最佳润湿雾-尘粒径比,之后对最佳润湿粒径比下的磁化活性液滴对煤尘的表面润湿行为机制及浸润效果进行了对比研究。结果表明,对于1μm、2.5μm、5μm、20μm、40μm、80μm的煤尘,其最佳润湿的雾尘粒径比分别为K=4、K=3、K=3、K=0.5、K=1、K=1;相比于普通水,磁化处理后的活性液滴在接触煤尘颗粒时表现出更高的润湿度和浸润效果;磁化活性水对无烟煤尘的沉降效率显著提高,对全尘及呼吸性粉尘的降尘效率高达89.71%、83.68%,较普通水提高40.16%、53.67%.研究证明了磁化活性水的降尘高效性,为湿式降尘喷雾技术的现场应用提供了理论支撑与指导。 展开更多
关键词 磁化活性水 多孔介质煤尘 固液粒径比 增效润湿
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加压工作条件下预膜空气雾化喷嘴燃油粒径预测模型研究
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作者 王波 苗家铭 +1 位作者 任光明 甘晓华 《推进技术》 北大核心 2026年第2期141-150,共10页
由于加压工作条件下雾化粒径数据的稀缺以及基于物理机制粒径预测模型的缺乏,本文开展了加压工作条件下预膜空气雾化喷嘴燃油粒径预测模型研究。通过试验设计(Design of Experiment,DOE),采用激光粒度仪测试了空气压力、空气温度、空气... 由于加压工作条件下雾化粒径数据的稀缺以及基于物理机制粒径预测模型的缺乏,本文开展了加压工作条件下预膜空气雾化喷嘴燃油粒径预测模型研究。通过试验设计(Design of Experiment,DOE),采用激光粒度仪测试了空气压力、空气温度、空气压降、燃油温度、油气比等多参数交叉影响下的雾化粒径数据,基于表面波不稳定理论构建了包含韦伯数、雷诺数、奥内佐格数等无量纲参数的预测模型。通过试验数据的验证,发现预测模型最大误差为14.1%,平均误差为5.2%,且残差符合正态分布。敏感性分析表明,预测模型准确捕捉了无量纲参数以及试验工况参数对粒径的影响。 展开更多
关键词 航空发动机 空气雾化喷嘴 加压工作条件 雾化粒径 多参数交叉影响 预测模型
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Microscopic and macroscopic atomization characteristics of a pressure-swirl atomizer, injecting a viscous fuel oil 被引量:6
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作者 Seyed Mohammad Ali Najafi Pouria Mikaniki Hojat Ghassemi 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第1期9-22,共14页
Combustion of heavy fuels is one of the main sources of greenhouse gases, particulate emissions, ashes, NOxand SOx. Gasification is an advanced and environmentally friendly process that generates combustible and clean... Combustion of heavy fuels is one of the main sources of greenhouse gases, particulate emissions, ashes, NOxand SOx. Gasification is an advanced and environmentally friendly process that generates combustible and clean gas products such as hydrogen. Some entrained flow gasifiers operate with Heavy Fuel Oil(HFO) feedstock. In this application, HFO atomization is very important in determining the performance and efficiency of the gasifiers.The atomization characteristics of HFO(Mazut) discharging from a pressure-swirl atomizer(PSA) are studied for different pressures difference(Δp) and temperatures in the atmospheric ambient. The investigated parameters include atomizer mass flow rate( _m), discharge coefficient(CD), spray cone angle(θ), breakup length(Lb), the unstable wavelength of undulations on the liquid sheet(λs), global and local SMD(sauter mean diameter) and size distribution of droplets. The characteristics of Mazut sheet breakup are deduced from the shadowgraph technique. The experiments on Mazut film breakup were compared with the predictions obtained from the liquid film breakup model. Validity of the theory for predicting maximum unstable wavelength was investigated for HFO(as a highly viscous liquid). A modification on the formulation of maximum unstable wavelength was presented for HFO. SMD decreases by getting far from the atomizer. The measurement for SMD and θ were compared with the available correlations. The comparisons of the available correlations with the measurements of SMD andθ show a good agreement for Ballester and Varde correlations, respectively. The results show that the experimental sizing data could be presented by Rosin-Rammler distributions very well at different pressure difference and temperatures. 展开更多
关键词 GASIFIER Heavy fuel oil atomIZATION Pressure-swirl atomIZER Mazut size distribution Wavelength Viscosity
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Effects of combinatorial water atomization on microstructures and properties of Cu-Sn powder 被引量:1
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作者 JIAChengchang MAHongqiu +1 位作者 JINChenghai GELiqiang 《Rare Metals》 SCIE EI CAS CSCD 2004年第2期143-146,共4页
A couple of additional cooling nozzles were assembled under traditionalatomization nozzles in order to improve the process and produce the powder with fine microstructureand low oxygen. The influence of the process pa... A couple of additional cooling nozzles were assembled under traditionalatomization nozzles in order to improve the process and produce the powder with fine microstructureand low oxygen. The influence of the process parameters on the properties of the powder wasinvestigated. The results show that finer powders with lower oxygen content and more irregular shapecan be achieved by combinatorial atomizing process comparing with normal one under the sameatomizing pressure. 展开更多
关键词 powder metallurgy combinatorial nozzle water atomization rapidsolidification particle size
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Experimental study of a heavy fuel oil atomization by pressure-swirl injector in the application of entrained flow gasifier 被引量:2
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作者 Pouria Mikaniki Seyed Mohammad Ali Najafi Hojat Ghassemi 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第4期765-771,共7页
The available SMD(Sauter mean diameter) correlations on pressure-swirl injectors predict droplet sizing very different from each other, especially for heavy fuels. Also there was a lack in the literature for comparing... The available SMD(Sauter mean diameter) correlations on pressure-swirl injectors predict droplet sizing very different from each other, especially for heavy fuels. Also there was a lack in the literature for comparing available correlations. So an experimental study was conducted on a heavy fuel oil(HFO) spray, Mazut 380. A pressure swirl injector was designed and fabricated. The experiments for Mazut at 40℃ and 80℃ were compared with the results for water, including spray half cone angle, breakup length and mean droplet diameter,at different injection pressures. Lower spray angle, higher breakup length and larger droplets were observed for lower injection pressures and higher liquid viscosity. SMD was about 75 μm for water and about 87 μm for Mazut at 80℃. The results for droplet mean diameter were also compared with correlations from previous studies on pressure swirl atomizers. The SMD results show that for water spray, LISA method was in good agreement,also Babu and Ballester correlations were successful when high viscosity fluid was injected. 展开更多
关键词 atomIZATION Pressure-swirl INJECTOR Mazut size distribution FUEL VISCOSITY
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Effect of closed-couple gas atomization pressure on the performances of Al-20Sn-1Cu powders 被引量:2
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作者 ZHAO Xinming XU Jun ZHU Xuexin ZHANG Shaoming 《Rare Metals》 SCIE EI CAS CSCD 2008年第4期439-443,共5页
Al-20Sn-1Cu powders were prepared by gas atomization in an argon atmosphere with atomizing pressures of 1.1 and 1.6 MPa. The characteristics of the powders are determined by means of dry sieving, scanning electron mic... Al-20Sn-1Cu powders were prepared by gas atomization in an argon atmosphere with atomizing pressures of 1.1 and 1.6 MPa. The characteristics of the powders are determined by means of dry sieving, scanning electron microscopy (SEM), optical microscopy (OM), and X-ray diffractometry (XRD). The results show that the powders exhibit a bimodal size distribution and a higher gas pressure results in a broad size distribution. All particles in both cases are spherical or nearly spherical and satellites form on the surface of coarse particles. Dendritic and cellular structures coexist in the particle. With decreasing particle diameter, the secondary dendrite arm spacing (SDAS) decreases and the cooling rate increases. The particles processed under high gas atomization pressure (1.6 MPa) exhibit a lower SDAS value and a higher cooling rate than those of the same size under low gas atomization pressure (1.1 MPa). The XRD results show that the Sn content increases with decreasing particle size. 展开更多
关键词 powder production Al-Sn-Cu alloy gas atomization rapid solidification particle size distribution
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Effects of atomization parameters of dust removal nozzles on the de-dusting results for different dust sources 被引量:7
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作者 Cheng Weimin Ma Youying +1 位作者 Yang Junlei Sun Biao 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第6期1025-1032,共8页
In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumptio... In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumption and droplet size are taken into account. The dust characteristics from different mines and atomization parameters of different pressure nozzles were measured. It was found that the internal pressure of coal cutters and roadheaders should be kept at 2 MPa, which could ensure large droplet size, large spraying angle and low water consumption and hence realizing a large-area covering and capture for large particle dusts. However, the external spray pressure should be kept at 4 MPa for smaller droplet size and longer effective spraying range, leading to effective dust removal in the operator zone. The spray pressure of support moving, drawing opening, and stage loader on a fully mechanized caving face and stage loader on a fully mechanized driving face should be kept at 8 MPa, under which the nozzles have long effective spraying range, high water flow and small droplet size for the rapid capture of instantaneous, high-concentration and small size dust groups. From the applications on the caving and driving faces in the coal mines, it is indicated that the optimization of spray pressure in different spraying positions could effectively enhance dust removal efficiency. Selecting appropriate nozzles according to the dust characteristics at different positions is also favorable for dust removal efficiency. With the selected nozzles under optimal pressures, the removal rates of both total dust and respirable dust could reach over70%, showing a significant de-dusting effect. 展开更多
关键词 Dust sources Dust size Types of spraying nozzle Spray pressure atomization parameters
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Revealing the atomistic deformation mechanisms of face-centered cubic nanocrystalline metals with atomic-scale mechanical microscopy: A review 被引量:1
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作者 Duohui Li Xinyu Shu +2 位作者 Deli Kong Hao Zhou Yanhui Chen 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2018年第11期2027-2034,共8页
Nanocrystalline metals have many functional and structural applications due to their excellent mechanical properties compared to their coarse-grained counterparts. The atomic-scale understanding of the deformation mec... Nanocrystalline metals have many functional and structural applications due to their excellent mechanical properties compared to their coarse-grained counterparts. The atomic-scale understanding of the deformation mechanisms of nanocrystalline metals is important for designing new materials, novel structures and applications. The review presents recent developments in the methods and techniques for in situ deformation mechanism investigations on face-centered-cubic nanocrystalline metals. In the first part,we will briefly introduce some important techniques that have been used for investigating the deformation behaviors of nanomaterials. Then, the size effects and the plasticity behaviors in nanocrystalline metals are discussed as a basis for comparison with the plasticity in bulk materials. In the last part, we show the atomic-scale and time-resolved dynamic deformation processes of nanocrystalline metals using our in-lab developed deformation device. 展开更多
关键词 In situ atomic-scale NANOCRYSTALLINE Deformation mechanisms size effect
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Influence of melt superheat on breakup process of close-coupled gas atomization 被引量:3
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作者 欧阳鸿武 陈欣 黄伯云 《中国有色金属学会会刊:英文版》 EI CSCD 2007年第5期967-973,共7页
In close-coupled gas atomization(CCGA), the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheatin... In close-coupled gas atomization(CCGA), the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size (D50) decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties, and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased from 250 K to 300 K, leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced. However, the log-normal distribution feature of particle size has not been substantially improved. 展开更多
关键词 气体雾化 耦合 喷嘴 颗粒尺寸 金属融化
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Preconcentration and Separation of Trace Copper in Water Samples with Nanometer-Size TiO_2 Colloid and Determination by FAAS 被引量:3
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作者 QIAN Shahua LIN Han LI Xueqin XIAO Mei DENG Hongbing XIANG Luojing 《Wuhan University Journal of Natural Sciences》 CAS 2007年第2期349-352,共4页
A new absorbent of nanometer-size TiO2 colloid for Cu(Ⅱ ) was studied in this work. The adsorption rate could reach above 99% when the pH values were at the range of 5-6. The adsorption balance time, adsorption cap... A new absorbent of nanometer-size TiO2 colloid for Cu(Ⅱ ) was studied in this work. The adsorption rate could reach above 99% when the pH values were at the range of 5-6. The adsorption balance time, adsorption capacities, and the eluent were investigated. A novel method of trace Cu( Ⅱ ) preconcentration and separation with nanometer-size titanium dioxide colloid and determination by flame atomic absorption spectrometry (FAAS) was advanced. The detection limit (3a) of the method was 1.15 μg · L^-1, and the relative standard deviation (R.S.D) was 1.53% (n=6). Environmental sample experiments were also conducted to test the feasibility of the method, and it came out that the recovery rates were between 95.9% and 97.8%. 展开更多
关键词 Cu( nanometer-size TiO2 colloid preconcentra-tion flame atomic absorption spectrometry (FAAS)
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Influence of Viscosity in Fluid Atomization with Surface Acoustic Waves
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作者 Andreas Winkler Paul Bergelt +1 位作者 Lars Hillemann Siegfried Menzel 《Open Journal of Acoustics》 2016年第3期23-33,共11页
In this work, aqueous glycerol solutions are atomized to investigate the influence of the viscosity on the droplet size and the general atomization behavior in a setup using standing surface acoustic waves (sSAW) and ... In this work, aqueous glycerol solutions are atomized to investigate the influence of the viscosity on the droplet size and the general atomization behavior in a setup using standing surface acoustic waves (sSAW) and a fluid supply at the boundary of the acoustic path. Depending on the fluid viscosity, the produced aerosols have a monomodal or polymodal size distribution. The mean droplet size in the dominant droplet fraction, however, decreases with increasing viscosity. Our results also indicate that the local wavefield conditions are crucial for the atomization process. 展开更多
关键词 Surface Acoustic Waves atomIZATION AEROSOL High Viscosity Droplet size Distribution Wavefield
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Atomic force microscopy study on eucaryotic ribosomes
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作者 徐磊 吴晓华 +1 位作者 刘望夷 李民乾 《Nuclear Science and Techniques》 SCIE CAS CSCD 1996年第1期10-15,共6页
AtomicforcemicroscopystudyoneucaryoticribosomesXuLei(徐磊),WuXiao-Hua(吴晓华),LiuWang-Yi(刘望夷)andLiMin-Qian(李民乾)(L... AtomicforcemicroscopystudyoneucaryoticribosomesXuLei(徐磊),WuXiao-Hua(吴晓华),LiuWang-Yi(刘望夷)andLiMin-Qian(李民乾)(LaboratoryofNuclea... 展开更多
关键词 真核生物 核蛋白体 原子力显微镜
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