Tailoring cotton fabric with wettability gradient and anisotropic penetration of liquid by spray coating

Abstract

Comfort has been one of the most important features of clothing, particularly for sportswear, which requires an effective transport of heat and moisture from the inner to the outer side of clothing. We herein report the use of a simple technique of spray coating and commercially available water repellents for a one-sided hydrophobic and self-initiated one-way water transport cotton fabric. The highlight of this work is the simplicity of the process and choice of chemicals that can be adopted easily by any textile finishing industry. On this fabric, water was able to diffuse and penetrate the fabric structure in one direction from the hydrophobic to the hydrophilic side but was unable to go the opposite direction. The directional transport improved with smaller droplets and lower add-on achievable by higher air pressure and longer distance of spray coating. From moisture management tests, the best result was obtained with the spray coating of Phobol NB-NH at an air pressure of 3.0?kgf/cm² and a distance of 120?cm. Phobol NB-NH gave better result of transport and overall comfort properties than Phobotex RSY.     

表面微结构金属干式电极制造及细菌粘附性能研究

为开发出高性能生物医用干式电极,提出了利用激光微铣-重铸加工方法,实现了表面具有微结构阵列特征的新型金属干式电极的制造成形。在分析电极表面微观形貌的基础上,研究了电极表面的润湿性能,并重点研究了扫描间距、扫描速度和扫描次数等加工参数对大肠杆菌粘附性能的影响规律。研究结果表明：在一定工艺参数条件下所加工出具有微结构阵列特征的电极的接触角可达150°以上,表现出超疏水的特性。在不同扫描间隙和扫描次数条件下加工出的电极对大肠杆菌的粘附性能具有较大影响,在选择0.1 mm扫描间隙时,电极表面粘附的大肠杆菌数量最少,适当增加扫描次数,也能够有效地减少电极表面大肠杆菌的粘结,从而发挥较好的抗菌效果。通过改变扫描速度加工出的电极则对大肠杆菌的粘附性能影响不大。     

Brazing of absorbers of planar solar heating collectors produced from materials of the Cu–CuZn system

The technology of brazing the absorber of planar solar heating collectors, consisting of a ray-receiving panel, produced from copper sheets with a composite selective coating and a tubular part, produced from L63 brass, is examined. The design of the absorber developed by the authors is described. The requirements on brazing technology to preserve the selective multilayer coating during heating of the Sun ray collector panel are determined. The experimental results are used for selecting the brazing alloys, fluxes and temperature–time parameters used in the development of the industrial technology of brazing the Sun ray collector panel of the absorber.     

Role of water wettability,water transport,and adhesion in vision

Water plays an important role in life processes, although the specifics are not always known. In the past 25 years, major progress has been made in vision science by applying the principles and techniques of interface science to tear film physiology and pathophysiology, to novel surgical techniques, and to contact lens wear. In this paper, the role and structure of the preocular tear film are discussed, as well as the factors affecting its stability. This double-layered fluid film plays an important role not only in vision and the health of the exposed ocular tissues, but also in deciding contact lens tolerance and functioning. The little-known, misunderstood, and often misdiagnosed dry eye syndrome that is effected by the compromised stability of the tear film is also discussed. A newly recognized role of water as a bioabhesive in ocular tissue adhesion and its failure in terms of disjoining pressure and weak boundary layer are examined in the vision-threatening and painful adhesion failure of corneal epithelium and epithelial trauma during routine ophthalmic procedures such as tonography. The modalities to prevent undesirable contact adhesion in intraocular surgery that could result in surgical complications arc explored. Retinal tears are thought to result from the adhesion failure of the retina to the underlying tissues. A concentric double membrane model of retinal adhesion is proposed that analyzes the role of certain biophysical factors such as elasticity and hydraulic conductivity in promoting or diminishing the adhesion of retina to the choroid.     

La在A1_2O_(3(sf))/Al-5.0%Cu复合材料界面的分布及界面结构研究

挤压铸造A12O3(sf)/Al-5.0%Cu复合材料时添加适量稀土La,并研究了界面附近La元素的分布。添加稀土后能明显的改善纤维与基体的润湿性,并促进了界面反应的发生,在纤维与基体合金之间生成致密的厚度约2μm的过渡层,并建立了界面的生成及结构模型。     

SrTiO3微纳米线的制备与亲疏水性

采用水热法，使用层状钛酸盐纳米线和氢氧化锶作为前驱物，在一定反应温度和反应时间的条件下简单地制备出了超细SrTiO3粉体。结果表明，只有在反应条件和反应物配比合适时才能得到纯的SrTiO3粉体。用X-射线粉末衍射仪和扫描电镜对SrTiO3粉体进行了表征。结果表明，所制备的SrTiO3粉体绝大部分为线状，长度约20μm，直径100～500nm。用接触角仪对所制备的SrTiO3粉体的亲疏水性进行了研究。结果表明，随着反应时间的延长，反应产物SrTiO3的纯度逐渐增加，由原来的完全亲水性转变为疏水性，接触角为36．820。     

Sn-Cu系无铅钎料的研究现状与发展

介绍了无铅钎料应用时应该满足的基本要求和Sn-Cu系无铅钎料的国内外研究和应用现状,概述了Sn-Cu系无铅钎料润湿性能、物理性能、力学性能等方面的一些特点,分析探讨了Sn-Cu系无铅钎料存在的不足,详细阐述了添加不同合金元素(如Bi、Ag、Ni、RE等元素)对Sn-Cu系无铅钎料性能的影响规律,并对Sn-Cu系无铅钎料的应用前景和发展方向进行了展望.     

Cr与B对镍基高温钎料在Cf/SiC陶瓷基复合材料上润湿性的影响

研究了Cr和B元素对镍基高温钎料在3D-Cf/SiC陶瓷基复合材料上的润湿性的影响.试验结果发现,在真空度小于10-3 Pa,工作温度1100 ℃,保温时间10 min条件下,当钎料中的Cr元素含量为15%,B元素含量为0.6%时,镍基钎料在Cf/SiC上的润湿角为10°,然而B元素含量增加到2.4%后,润湿角增大到62°,表明钎料中的元素B降低钎料在Cf/SiC上的润湿性.钎料中的活性元素Cr对润湿有重要影响.镍基钎料在Cf/SiC上的润湿过程属于反应润湿,润湿界面生成多种碳化物和硅化物.采用扫描电镜与能谱仪分析界面的微观结构与成分,通过X射线衍射仪检测界面产物.     

石墨烯纳米片对AgCuTi钎料熔点与润湿性的影响

采用球磨法在AgCuTi钎料中添加不同质量分数的石墨烯纳米片(GNSs)制备出复合钎料,利用差示扫描量热仪(DSC),SEM以及XRD等方法研究了微量的石墨烯纳米片对AgCuTi钎料微观形貌、熔点以及在蓝宝石表面润湿性的影响. 结果表明,球磨法对GNSs-AgCuTi复合钎料的物相没有影响,石墨烯均匀地分散在AgCuTi颗粒周围;复合钎料熔点随着石墨烯含量的增加而降低,当石墨烯含量为0.5%,熔点降低了3.2 ℃;微量的石墨烯,改善钎料在蓝宝石表面的润湿性,0.3%GNSs-AgCuTi复合钎料的润湿角减小了4.4°,铺展面积增加了10 mm²,而过多的石墨烯也使得复合钎料的润湿性变差;石墨烯与元素Ti反应生成TiC,复合钎料与蓝宝石界面反应产物为Ti₃Cu₃O相.     

不同预处理方法对稻秸纤维表面性质的影响

通过对稻秸原料进行水热、酸碱和冷等离子体预处理,分析了纤维表面的浸润性及表面自由基浓度的变化。研究表明,经水热及酸碱预处理后,纤维与水的接触角为90o,稻秸纤维的浸润性改善不明显,经冷等离子改性后,稻秸纤维表面浸润性改善非常明显。水热及乙酸处理有利于提高稻秸纤维的表面自由基浓度,碱处理则降低了稻秸纤维的表面自由基浓度。