仿生亲水微轨道-超疏水复合表面液滴可控定向引导研究

目的 实现液滴在超疏水表面定向可控滑动.方法 通过一种简单而有效的方法制备复合仿水稻叶亲水微轨道的超疏水表面.首先使用NaOH腐蚀铝合金表面形成微纳结构,然后浸泡硬脂酸溶液使得粗糙表面自生长硬脂酸超疏水层,最后使用纳秒激光系统去除局部超疏水层,形成用于引导液滴的仿水稻叶微轨道.利用超疏水表面的超强憎水特性及亲水微轨道的亲水性,得到水滴运动各向异性的微结构化表面.通过优化微轨道参数,改变液滴各向异性润湿及滑动特性.结果 随着相邻亲水微轨道间隔的减小,平行微轨道方向接触角也明显减小,液滴沿轨道方向的滑动阻力明显增加.当相邻微轨道间距为500μm时,达到平行亲水微轨道方向和垂直亲水微轨道方向滑动角的差值超过50°,为液滴可控定向引导最佳间距.进一步提出了具有变密度亲水微轨道和曲线排列亲水微轨道的超疏水表面,其具有在特定单方向液滴可控引导的特性,并引导水滴沿微轨道聚集到亲水末端点.通过机理分析得出,液滴在复合表面的各向异性润湿和定向滑动,是由于超疏水表面和亲水微轨道之间的表面能性质差异,以及毛细作用引起的预润湿效应等.结论 本研究制备的复合亲水微轨道超疏水表面可实现液滴定向引导,在集水、水滴混合及污渍去除等领域具有应用潜力.     

NIR驱动MWCNT修饰的超滑PI光热响应膜表面液滴定向输运

目的 制备多壁碳纳米管(MWCNT)修饰的超滑聚酰亚胺(PI)光热响应膜表面,实现近红外光(NIR)驱动液滴定向输运.方法 基于静电纺丝结合喷涂法制备MWCNT修饰的超滑PI光热响应膜表面,分别通过扫描电子显微镜、接触角测量仪、红外热成像仪表征样品的微观形貌、润湿特性及光热特性,分析液滴大小与润滑油黏度对液滴定向输运的影响规律,研究NIR驱动液滴在MWCNT修饰的超滑PI光热响应膜表面定向输运的作用机理.结果 MWCNT修饰PI膜表面的疏水性提高,液滴静态接触角从115°增大至160°.NIR连续照射MWCNT修饰的超滑PI光热响应膜表面90 s,表面温度的最大上升速率为42.6℃/s,表面最大温度达到123.6℃.通过NIR照射超滑PI纳米纤维膜表面,表面局部温度上升,产生润湿梯度力,驱动液滴在表面定向输运.液滴定向输运与润湿梯度力及粘滞阻力有关.超滑PI光热响应膜表面的润滑油黏度相同时,液滴体积越小,粘滞阻力越小,液滴定向输运的速度越快.5μL液滴在润滑油黏度为0.65 mm2/s的超滑PI光热响应膜表面的运动速度最大,运动速度为1.64 mm/s.液滴体积相同时,超滑PI光热响应膜表面的润滑油黏度越大,液滴受到的润湿梯度力越小.5μL液滴在润滑油黏度为100 mm2/s的超滑PI光热响应膜表面的润湿梯度力Fwet-grad最小,润湿梯度力为6.39×10?6 N.结论 MWCNT修饰的超滑PI光热响应膜表面具有良好的光热效应,NIR可精准驱动单液滴及多液滴在表面的定向输运.     

激光图案化铝合金表面的润湿性和各向异性研究

目的 研究水滴在超亲/超疏水图案化铝合金表面润湿性、滚动阻力各向异性和定向运输特性。方法 采用激光刻蚀和氟硅烷修饰的方法,加工出具有微网格图案的超疏水6061铝合金表面。在超疏水铝合金表面再次激光刻蚀加工出长方形、平行四边形和圆形的超亲水微流体通道。研究了亲水沟槽宽度和深度对超亲/超疏水表面各向异性润湿和各向异性滚动的影响,分析了重力作用下水滴沿微流体通道的运动情况。利用SEM、三维轮廓仪观察铝合金表面形貌。利用接触角测量仪观测水滴与表面的接触角与滚动角大小。利用高速摄像机观察水滴的运动情况。结果 水滴在超亲/超疏水铝合金表面表现出明显的润湿性各向异性和滚动阻力各向异性。10μL水滴在0.1 mm宽度的直线型沟槽上铺展,平行接触角θ_cp仅为93.9°;而垂直于线型沟槽方向,垂直接触角θ_cv却为152.6°。平行滚动角θ_rp为21.5°,而垂直滚动角θ_rv大于90°,水滴无法滚落。基于超亲/超疏水表面滚动阻力各向异性的特性,制备了依靠重力驱动实现微流体定向运输的铝合金表面。结论 亲水沟槽宽度对水滴在超...     

润湿性表面液滴导向运动的研究进展

润湿性表面的液滴操控技术由于其在微流控系统设计、生物医学分析、淡水收集、喷墨打印以及换热器等领域具有广阔的应用而备受学者关注.详细介绍了液固接触和液滴运动的基本理论.综述了近年来国内外学者对于润湿性表面上液滴导向传输技术的研究进展,按不同的润湿性表面涉及的不同驱动力,归纳了液滴在润湿性梯度表面上受表面梯度驱动、在超疏水基底异性轨道表面上受重力驱动、在超疏水表面上受外场驱动的三种导向运动,着重阐述了从理论分析到实验实现润湿梯度表面驱动液滴的发展脉络、超疏水基底异性轨道表面的制备方法、液滴运输实验研究和受光、电、热、磁外场响应的不同液滴驱动传输机制,分析对比了各种液滴传输技术的优缺点.最后,提出了对润湿性表面上液滴做曲线运动过程中深入到离心力、表面张力等影响运输可控性的力学特性研究,展望了耦合多外场结合固体润湿性表面的优化设计,来控制多液滴独立导向运动的重要方向,并简要介绍了未来的应用前景.     

可切换润湿性超疏水表面制备方法及应用

目的 制备可切换润湿性的智能超疏水表面,并探索该表面潜在的应用前景。方法 利用模板法,基于热响应形状记忆聚合物（Shape Memory Polymer,SMP）制备具有条状微结构阵列的可切换润湿性智能超疏水表面,并对其润湿性可逆转换能力及循环使用稳定性进行测试。结果 通过扫描电子显微镜观察到所制备表面微结构完整且轮廓清晰,液滴接触角在该表面可达到（150±3）°。通过加热使该表面达到玻璃化转变温度,此时对其施加外载荷使表面上条状微结构向一侧倾倒,由于微结构形态的改变,SMP表面疏水性减弱、水黏附性增强,再通过简单加热就可以使表面形态恢复至原始状态。通过试验测得环氧SMP的形状固定率为98.8%、形状回复率为96.3%,均达到95%以上,由于其优异的形状记忆特性,条状微结构的形态可以在原始直立状态和受到外载荷时的倾倒状态之间产生热响应而自由转变,且这种润湿性转换循环10次以上后,该表面依然保持着相对良好的润湿性可逆转换能力。结论 基于形状记忆聚合物制备出的可切换润湿性智能超疏水表面具有良好的润湿性可逆转换能力和循环使用能力,且在液滴微反应器、生物检测、可重写液体图案、无损失液滴转移和芯...     

不同润湿性液体在粗糙表面的润湿滞后现象

润湿滞后是表征液体脱离固体表面难易程度的核心参数。为了研究不同润湿性状态下的润湿滞后现象,在定量描述固体表面粗糙度的基础上,首次在3种不同粗糙度固体表面上对强亲水到疏水范围内的液体进行系统的Wenzel接触角及润湿滞后实验,在通过Wenzel理论及静摩擦力理论验证座滴法与体积法实验结果准确性的前提下,进一步研究不同润湿性状态下杨氏接触角、粗糙度与润湿滞后之间的定性关系。结果表明:固体样品1(固体表面粗糙度,r=1.15)的润湿滞后效应在不同润湿状态下保持一常数,而固体样品2(r=1.64)及固体样品3(r=2.29)的润湿滞后效应在θ_e=90°附近达到最大,随着亲水和疏水程度的增加,润湿滞后效应均不断减小;粗糙度与润湿滞后的关系也并不单调,在亲水状态下,润湿滞后效应随着粗糙度的增加而减小,而在中性润湿状态下未发现明显规律。     

基于MATLAB分析不同形貌对金属表面润湿性能的影响

目的 研究不同形貌的微结构表面对金属表面润湿性能的影响。方法 首先在金属材料表面建立一级与二级微结构模型,然后整理得出不同微结构模型评定参数的公式,最后利用Matlab对不同形貌表面相关公式进行模拟计算,绘制得到不同形貌表面润湿特性三维曲线。结果 一级微结构中,球形微结构模型表面表观接触角θ皆为定值,即完全润湿θc=74.443°,不完全润湿θw=131.720°。其余微结构模型利用Matlab模拟计算,均可以得到光滑的三维曲线,其中在铜基表面设计制备三维方柱阵列微结构,可获得超疏水特性。二级微结构中,比较完全润湿状态,不完全润湿状态粗糙因子f远小于Υ。在不完全润湿状态中,粗糙因子f趋近于0,与完全润湿状态模拟的表观接触角结果相比,不完全润湿状态下,采用三维阵列微结构研究金属表面微结构对表观接触角的影响最为合适。结论 模拟条件相同的情况下,改变金属表面微观形貌会引起润湿性能的改变。金属表面润湿性能与表面微细结构以及微结构参数均存在映射关系,但是表面微结构的维度并非越高越好,一级微结构同样也可以得到所需疏水性能。在外在影响因素相同的条件下,若要研究分析金属表面微结构参数的改变对表观接触角的影响,采用三维阵列微结构最为合适。     

透明超疏水表面的研究进展

对于太阳能电池系统、汽车挡风玻璃、相机镜头等光学器件,高透明性是其功能的最重要指标之一.由于这些设备经常暴露在室外,大量的灰尘污垢会严重影响其性能.透明超疏水表面由于具有优异的光学和抗污性能,在光学器材领域有着很高的应用前景.首先总结了表面润湿性理论,主要包括Young润湿方程、Wenzel润湿模型和Cassie润湿模型,通过润湿性理论指出制备超疏水表面的条件——低表面能物质和粗糙结构二者缺一不可.其次,讨论了粗糙度和透明度之间的竞争关系,通过瑞利散射和米氏散射理论,得出制备透明超疏水表面还需要同时满足材料表面粗糙度小于100 nm.然后,归纳总结了近十年来透明超疏水表面常见的制备方法,如溶胶凝胶法、化学气相沉积法、模板法、相分离等方法,并对这些制备思路和方法进行了分析,概括了这些方法当前存在的一些问题.最后,简单介绍了透明超疏水表面在太阳能电池、光学元器件、光催化材料等领域的应用,并对透明超疏水表面的未来研究方向和应用前景进行了展望.     

超疏水表面微结构的设计及其注射成型

目的 从超疏水表面的功能设计出发,主动设计三种深宽比的微结构阵列并洞察其在不同润湿接触状态下的疏水性能。方法 首先,采用热力学分析方法,建立三种深宽比微结构的系统自由能与其接触角、结构几何参数之间的函数关系,探明自主设计微结构表面的润湿性能。继而,在热力学分析的基础上,采用紫外光刻、电铸和注射成型技术相结合的方法实现三种深宽比微结构聚丙烯（PP）超疏水表面的制备。最后,进一步测量与分析聚丙烯（PP）微结构表面的润湿性能。结果 三种深宽比微结构表面的静态接触角测量值均大于150?,滚动角分别为12?、14?和15?,基本达到设计目标;同时,微结构表面的表观接触角测量值与理论计算值基本符合。表面的接触角滞后分别为15?、21?、22?,且接触角滞后随着深宽比的增加而变大,使液滴在PP表面的流动性也变差。结论 在设计微结构超疏水表面的过程中,可以适当降低微结构的深宽比,以获取更好的超疏水特性。自主设计的微结构表面基本实现超疏水性,为高聚物超疏水表面的功能设计与高效制备提供了理论依据与技术支撑。     

超疏水性聚合物表面宏观结构对液滴撞击行为影响∗

超疏水性表面的液滴撞击是普遍存在的现象,研究具有不同尺寸和形状宏观结构的超疏水性表面对液滴撞击行为和接触时间的影响,对于其潜在应用具有重要的理论指导作用。 采用等离子体纳米织构化方法在平整与具有矩形、半圆形和三角形宏观结构的聚乙烯表面上制备超疏水性纳米线结构,通过高速摄像机观察超疏水性聚乙烯表面的液滴撞击行为,分析撞击液滴的形状演变和接触时间变化。 研究表明:超疏水性聚乙烯表面的矩形、半圆形和三角形宏观结构可显著改变液滴的撞击行为,液滴铺展后回缩过程的缩减加速了超疏水性表面液滴的弹离,有效降低了超疏水性表面的固液接触时间。 超疏水性聚乙烯表面的矩形、半圆形和三角形宏观结构尺寸小于液滴直径时,均可造成高速撞击液滴分裂,液滴的分裂回弹导致固液接触时间进一步降低,接触时间最低可达到约 4. 8 ms。 疏水性表面的宏观结构有利于固液接触时间降低,具有宏观结构的疏水表面展现出抗水滴高速撞击的去润湿性能。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.