表面亲疏水特性对毛细管内双组分渗流特性的影响

垫片密封泄漏预测模型一般基于Hagen-Poiseuille定律。该定律适用于气体或液体的单组分泄漏预测，而对于双组分或多组分介质的泄漏，其适用性有待进一步研究。在考虑泄漏通道亲疏水特性的基础上，采用格子玻尔兹曼方法（LBM）模拟矩形微通道内的双组分渗流过程，获得不同密度的双组分介质在毛细管内流动的基本规律。研究发现，通道的亲水和疏水特性对双组分渗流的影响显著，具体表现为黏滞在亲水性壁面上的重组分使流动通道的截面积缩小，从而使轻组分的流量下降。研究表明，双组分在亲水性壁面通道内的流动不同于一般的双组分混合流动，因此在利用Hagen-Poiseuille定律预测渗流时需对公式进行修正。     

Hydrophobic-associated polymer-based laponite nanolayered silicate composite as filtrate reducer for water-based drilling fluid at high temperature

Wellbore instability caused by water invasion is the main problem in oil and gas drilling operation. This study reports the utilization of a hydrophobic-associated polymer-based laponite nanolayered silicate composite as a filtrate reducer in water-based drilling fluids (WDFs). The thermal performance and micromorphology of the composite were analyzed by thermogravimetric analysis, transmission electron microscope, and field emission scanning electron microscopy. The results indicated that the composite possessed a “bean pod” structure and a good thermal stability. The rheological properties of the composite solution were evaluated. The results showed that the hydrophobic association interaction of the composite is weak but existent, and the crosslink network structure is variable. The applied performances of WDFs containing the composite were also evaluated. Evaluation results showed that the composite could improve the properties of the thermal stability, salt tolerance, and fluid loss control of WDFs. The particle size distribution of WDFs and the micrographs of filter cakes explained the improving. The composite was expected to be applied as an efficient filtrate reducer for developing high performance drilling fluids. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48608.     

Production of New Functionalized Polymer Nanoparticles and Use for Manufacture of Novel Nanobiocatalysts

New nanoparticles are synthesized through emulsion polymerization, using distinct comonomers (styrene, divinylbenzene, glycidyl methacrylate and pentafluorostyrene). Then, for the first time, two strategies are adopted to functionalize such nanoparticles using benzylamine and thiophenol: (i) after the manufacture of the nanoparticles; and (ii) in situ during the polymerization reaction. Afterwards, the functionalized nanoparticles are used as nanosupports for immobilization of lipase B from Candida antarctica and the performance of the novel nanobiocatalysts are evaluated. It is shown that the nanoparticles exhibit different properties (specific areas ranging from 34 m² g^?1 to 324 m² g^?1; and contact angles ranging from 29° to 126°), indicating that both procedures can be used to adjust the properties of the polymer supports. Moreover, the nanobiocatalysts are applied successfully in hydrolysis and esterification reactions, exhibiting higher activities than the non‐functionalized biocatalysts. It is also observed that more hydrophilic supports result in more active biocatalysts in hydrolysis (27 ± 1 U g^?1) and intermediate hydrophobic matrices conduct to more active biocatalysts in esterification reactions (1564 ± 50 U g^?1). It is shown that highly hydrophobic surfaces may cause a significant decrease in the activity of such biocatalysts, probably due to distortions on the enzyme active center and to more intense chemical partitioning effects.     

AH32钢表面等离子喷涂制备疏水涂层及其耐腐蚀性能研究

目的提高AH32海洋用钢表面的疏水性及耐蚀性,并给出最佳性能的喷涂涂层成分。方法采用大气等离子喷涂技术,在AH32钢表面制备了三种不同成分的涂层。利用微量进样器结合半球法测量了涂层的接触角,并利用Qwen-Wendt公式对涂层的表面能进行了计算,利用扫描电子显微镜观察涂层的表面形貌,利用表面粗糙度仪测量涂层的表面粗糙度,利用冲刷实验及电化学工作站测量了不同涂层的耐蚀性能,并讨论了不同涂层的疏水机制及相应的腐蚀机理。结果等离子喷涂涂层显著改善了AH32钢的疏水性能。相比而言,等离子喷涂Co基涂层及等离子喷涂Ni基涂层与水的静态接触角达到了130°以上,均具有较好的疏水效果。三种涂层均明显改善了AH32钢的耐海水冲刷腐蚀能力,其中AH32钢基体腐蚀30d后的失重为1.68×10^-2 g/cm^2,等离子喷涂Ni基涂层的腐蚀失重最小,约为4.2×10^-3 g/cm^2。极化曲线测试结果也表明,三种涂层的自腐蚀电位较基体提高了300 mV左右,并且腐蚀电流密度较基体降低了1个数量级以上,另外Co基涂层的腐蚀电流密度高于Ni基涂层的腐蚀电流密度,因此Co基涂层在腐蚀过程中表面会产生较多的羟基基团,导致其与水的静态接触角降低,最终导致其疏水性能下降。结论等离子喷涂Ni基涂层的疏水性能最好,腐蚀速率最小,耐冲刷腐蚀性能最佳,与基体相比,其腐蚀失重减小了1.26×10^-2 g/cm^2。     

Effects of slip length and hydraulic diameter on hydraulic entrance length of microchannels with superhydrophobic surfaces

This paper investigated effects of slip length and hydraulic diameter on the hydraulic entrance length of laminar flow in superhydrophobic microchannels. Numerical investigations were performed for square microchannels with Re ranging between 0.1 and 1000. It is found that superhydrophobic microchannels have a longer hydraulic entrance length than that of conventional ones by nearly 26.62% at a low Re. The dimensionless hydraulic entrance length slightly increases with the increasing slip length at approximately Re<10, and does not vary with the hydraulic diameter. A new correlation to predict the entrance length in square microchannels with different slip lengths was developed, which has a satisfying predictive performance with a mean absolute relative deviation of 5.69%. The results not only ascertain the flow characteristics of superhydrophobic microchannels, but also suggest that super hydrophobic microchannels have more significant advantages for heat transfer enhancement at a low Re.     

Bitter-tasting hydrophobic peptides prepared from soy sauce using aqueous ethanol solutions influence taste sensation

In this study, bitter-tasting hydrophobic peptides were prepared and purified from soy sauce using aqueous ethanol solutions and ion exchange resin, and analysed using RP-HPLC and UPLC-Q-TOF-MS/MS. Most of bitter fraction from soy sauce was obtained by treatments involving 80% ethanol and subsequent chromatographic separation. This fraction contained sixteen small peptides (molecular weight < 1000 Da; rich in hydrophobic amino acids with Lys-Pro (KP), Glu-Phe (EF), Glu-Val (EV), Asp-Leu (DL), Leu-Trp (LW) and Asp-Pro (DP)) capable of enhancing significantly (P < 0.05) umaminess and/or imparting kokumi effect in taste reconstitution experiments. Thus, the bitter peptides affected bitterness as well as other taste sensations like umaminess, kokuminess and saltiness. This was the first study to report the impacts of the bitter-tasting hydrophobic peptides on soy sauce and solutions of salt, monosodium l -glutamate.     

高疏水PAN的制备及其性能

以磷酸和环氧树脂E20制备了水性的磷酸改性环氧树脂(PAER)，考察了反应温度、反应时间、投料比等因素对环氧树脂转化率的影响，得到了制备PAER的最佳条件。采用傅里叶变换红外光谱和核磁共振波谱对PAER结构进行了表征。用KOH中和PAER得到磷酸改性环氧树脂的钾盐(PAERK)，测试了PAERK乳液的性质。使用含氟表面活性剂(FP?6812)与PAERK复配制得了含氟改性环氧树脂钾盐(PAERKF)，测试了PAERKF乳液施覆改性前后聚丙烯腈纤维(PAN)与水的接触角及纤维在环氧树脂中的分散性，并通过场发射扫描电子显微镜对纤维的表面形貌进行了观察。结果表明，PAERKF的最佳上浆浓度为0.6 %(质量分数，下同)，最佳施覆量为5.0 mg/g；经PAERKF施覆改性后的PAN纤维与水的接触角可达146.94°，纤维具备了高疏水特性；经PAERKF施覆改性后的PAN在环氧树脂基体中的分散系数(β)可达0.89，纤维在树脂基体中的分散性得到改善。     

疏水性金属-有机骨架材料的研究进展

金属-有机骨架（metal-organic frameworks, MOFs）材料是一种由金属离子和有机配体通过自组装形成的新型多孔材料，具有优异的物理及化学性能，因而在气体吸附储存、气体分离以及工业催化等方面表现出良好的应用潜力。但在应用的过程中，无处不在的水分子会影响MOFs骨架的稳定性和吸附性能，极大地制约了其实际应用。本文介绍了近年来疏水性MOFs材料的研究进展，重点论述了金属离子和有机配体对调控MOFs亲疏水性的影响以及通过配体后修饰和疏水性物质复合等提高疏水性的方法，分析了MOFs材料的亲疏水性机理，同时提出了实验结合计算机模拟技术筛选疏水性MOFs的手段。最后，指出目前疏水性MOFs材料合成存在的问题及解决方法，期望为今后拓宽MOFs材料在高湿环境中的应用提供一些有用的参考。     

A review on ice detection technology and ice elimination technology for wind turbine

Blade icing can affect wind turbines to generate electricity. In severe cases, 30% of power generation is lost in a year, and safety problems in the vicinity of wind power plants are also caused. Researchers have designed anti‐icing and de‐icing technologies to reduce these effects, and excellent ice‐detecting devices are a prerequisite for using anti‐icing and de‐icing technologies. Ultrasonic attenuation technology can effectively and reliably detect the presence of ice without affecting the aerodynamic performance of the blade, providing a reliable guarantee for anti‐icing and de‐icing systems. Deicing and anti‐icing systems are divided into active and passive, active heating blades are still the most effective anti‐icing and de‐icing methods, but their energy consumption is too high. Although there are many existing de‐icing methods, there are not many practical uses. This article introduces them separately and lists their advantages and disadvantages. The use of ultrasonic anti‐icing and de‐icing is an economical and reliable means that has been proven to be used for anti‐icing and de‐icing of blades. However, under normal circumstances, a single anti‐icing de‐icing system cannot completely solve the problem of icing of the blades. This paper suggests using both ultrasonic and hydrophobic coatings to cope with more icing conditions.