Facile Formation of Hierarchical Textures for Flexible,Translucent, and Durable Superhydrophobic Film

Flexible superhydrophobic surfaces have recently attracted extensive interest not only in the field of burgeoning flexible electronics, but also for the practicability toward various situations. Herein, a cost-effective and environment-friendly approach is demonstrated to realize the durable, flexible, and superhydrophobic film with optical transparency. Without sophisticated facilities, the essential hierarchical architecture to render a low-adhesive surface is achieved via magnetic field-assisted polydimethylsiloxane microcilia, followed with the swelling process to decorate nanoscaled particles with excellent robustness. This tight connection between the microcilia and decorated nanoparticles renders the mechanical robustness with resistance to ultrasonic treatment, sandpaper abrasion, and high-speed water impact. The film further exhibits outstanding stabilities when exposed to organic contamination, hot water, and chemical corrosions. Water repellency is well preserved when the film is under various mechanical deformations including cyclic stretching, bending, and squeezing. For practical demonstrations, the film is applied as the protective film for touch screen owing to the intrinsic optical transmittance, or serves as the water-proof covers for sorts of complex/curved surfaces. These stated features reveal the convincing potential of the methodology to be applied for the circumstances where simultaneous addressing of robustness, flexibility, and adaptability is highly appreciated.     

Gel-cast hierarchical porous B4C/C preform and its role in fabricating reaction bonded boron carbide composites

The resorcinol-formaldehyde (RF) gel-casting system is employed for the first time to fabricate a hierarchical porous B₄C/C preform, which was subsequently used for the fabrication of reaction bonded boron carbide (RBBC) composites via a liquid silicon infiltration process. The effect of the carbon content and carbon structures of this perform on the microstructures and mechanical properties of B₄C/C preform and the resultant RBBC composites is reported. The B₄C/C preform (16 wt% carbon) exhibit a strength of 34±1 MPa. The obtained RBBC composites shown uniform microstructure is consisted of SiC particles bonded boron carbide scaffold and an interpenetrating residual silicon phase. The Vickers hardness, flexural strength and fracture toughness of the RBBC composites (16 wt% carbon) are 24 GPa, 452 MPa and 4.32 MPa m^1/2, respectively.     

High performance MnO2 nanoflower supercapacitor electrode by electrochemical recycling of spent batteries

MnO₂ nanoflower is prepared by electrochemical conversion of Mn₃O₄ obtained by heat treatment of spent zinc‒carbon batteries cathode powder. The heat treated and converted powders were characterized by TGA, XRD, FTIR, FESEM and TEM techniques. XRD analyses show formation of Mn₃O₄ and MnO₂ phases for the heat treated and converted powders, respectively. FESEM images indicate the formation of porous nanoflower structure of MnO_2, while, condensed aggregated particles are obtained for Mn₃O₄. The energy band gap of MnO₂ is obtained from UV‒Vis spectra to be 2.4 eV. The electrochemical properties are investigated using cyclic voltammetry, galvanostatic charge‒discharge and electrochemical impedance techniques using three-electrode system. The specific capacitance of MnO₂ nanoflower (309 F g⁻¹ at 0.1 A g⁻¹) is around six times higher than those obtained from the heat treated one (54 F g⁻¹ at 0.1 A g⁻¹). Moreover, it has high capacitance retention up to 93% over 1650 cycles. Impedance spectra of MnO₂ nanoflower show very small resistances and high electrochemical active surface area (340 m² g⁻¹). The present work demonstrates a novel electrochemical approach to recycle spent zinc-carbon batteries into high value supercapacitor electrode.     

分子电性作用矢量用于合成产率预测

应用分子电性作用矢量(molecular electronegativity interaction vector,MEIV)建立了42种Wittig反应产率的定量构效关系模型,考察了反应物分子结构对合成产率的内在影响。结合多元线性回归、逐步回归变量筛选方法和QSAR建模技术,得到7参数QSAR模型,交互校验的复相关系数分别为0.985、0.973;选用外部集对模型健壮性、预测能力进行考察,亦获得良好结果:R=0.984、R=0.965。模型稳定性良好,预测能力颇强。     

High efficient corrosion inhibition of steel by nano-micro aggregates of Sapindus mukorossi Gaertn peel extracts

To seek green, sustainable and natural plant extracts with the potential for large-scale application as corrosion inhibitors, this article selects the extracts of the Sapindus mukorossi Gaertn peels with surfactant properties as the research object. Hence, this article uses Sapindus mukorossi Gaertn peel extracts (SMGPE) with surfactant properties as the study candidate. This survey presents efficient extraction of Sapindus mukorossi Gaertn peels by simply refluxing ethanol solution. It is shown that SMGPE can process orderly nano-micro meters aggregation in DMF/HCl (volume ratio: 50/50, 1.0 mol/L HCl solution) mixed solution through self-organization at the room temperature.The results show that the predominantly strong chemical adsorption of formed SMGPE aggregates on the studied Q235 steel specimens is suggested through the detection of FT-IR, Raman as well as XPS spectroscopy. This study further determines the corrosion inhibition effect of the stable SMGPE aggregates for the studied steel specimens in 1.0 mol/L HCl aqueous solution based on electrochemical method. The results suggest that the SMGPE aggregates can inhibit corrosion of the steel specimens in HCl solution efficiently, and the greatest corrosion inhibition efficiency is over 90%.     

改善明胶生产废水污染的磷酸氢钙回收工艺

在考察明胶生产工艺、废水水质特性的基础上,提出一改进的磷酸氢钙清洁回收工艺。在浸灰工段后设一沉淀池,沉淀分离石灰沉渣,将上层饱和的氢氧化钙浸灰废液送至浸酸工序,处理浸酸废液,调pH至4.7左右,回收磷酸氢钙。而原工艺是用灰乳处理浸酸废液回收磷酸氢钙,大量饱和Ca(OH)_2浸灰废液外排,造成了难于治理的明胶生产废水高碱、高钙、高悬浮有机物污染。实验证明,该改进工艺能消耗大量的浸灰废液,有效降低明胶生产废水的高碱特性,对悬浮COD的去除效果与使用普通净水剂效果相当,且对磷钙复合肥的收率无重大影响,所排废液不再是饱和的氢氧化钙溶液,钙污染也得到一定控制,与原废水相比生化处理难度大大降低,具有显著的环境效益。     

Study of the behavior of adsorbing CS2 by activated carbon

The adsorption of carbon disulfide on one raw and three modified activated carbon samples at different temperatures from 303 K to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus. The amounts of carbon disulfide adsorbed by three modified carbon samples are all larger than that of the raw one. It is found that organic amine is more effective than KOH as active ingredient for modification of activated carbon. The Freundlich equation is found to be the best model to fit the isotherm data for the four carbon samples at different temperatures studied.The isosteric heats of adsorption on the four carbon samples, derived from the adsorption isotherms using the Clapeyron equation, decrease with increase of surface loading. The heat of adsorption lies between 17.7 and 51.4 kJ/mol, where the carbon sample modified with KOH and ethylenediamine has the highest value with the exception of the case of high surface coverage (> 3.5 mmol/g). It is also found that the choice of adsorption isotherm has a significant influence on the values of isosteric heat of adsorption calculated. The isosteric heats of adsorption at zero surface loadings for the four carbon samples are 53.93, 53.87, 45.17 and 65.54 kJ/mol respectively and the carbon sample modified with KOH and ethylenediamine has the highest value. Analysis of the thermodynamic data shows the mobility of adsorbed carbon disulfide increases with increase of surface loading in all cases. The observed entropy change associated with the adsorption is higher than the theoretical value for the mobile adsorption but lower than the theoretical value for the localized adsorption in all cases except the carbon sample modified with KOH and ethylenediamine at higher surface coverage (> 4 mmol/g). The observed entropy change also decreases with increase of surface loading in all cases.     

原子电性作用矢量和杂化状态指数用于酮类化合物核磁共振QSSR研究

从分子二维结构出发,采用反映分子局部化学微环境结构表述指数———原子电性相互作用矢量(AEIV)和原子杂化状态指数(AHSI)对201个酮分子中的1 373个碳原子的13CNMR谱建模模拟,取得了满意结果。所得定量结构波谱关系(QSSR)的多元线性回归模型复相关系数RMM及留一法交互检验相关系数RCV分别为0.966和0.965。进一步随机抽出5个化合物中共计196个13CNMR化学位移用于模型外部验证,预测结果复相关系数Rpred=0.965,上述结果表明所建模型有良好的稳定性和泛化能力。     

油润滑纳米添加剂摩擦学设计及研究中几个值得商榷的问题

从材料学、化学、摩擦学、表面工程角度分析阐述了纳米润滑油添加剂组分选择、分散稳定修饰剂设计、摩擦学性能评价和机理研究方面存在的几个问题和认识上的一些误区．指出在作油润滑纳米润滑材料的摩擦学设计时，所选择的纳米材料应对酸、氧特别是热氧和纳米修饰剂表现出惰性；对普通摩擦副来说，纳米粒子的“分子轴承”作用机制其作用微乎其微的。当摩擦副相互接近程度达到介观或微观尺度时．纳米微球的“分子轴承”作用才明显，产生润滑甚至超润滑；对普通摩擦副而言，纳米粒子在短时间内的机械抛光作用并不会太明显，而长期抛光作用则取决于摩擦过程中纳米粒子机械抛光作用和机械摩擦磨损作用两者之间的竞争。     

微波闪速合成纳米ZrO_2/ZnO复合材料及其光催化性能研究

以硝酸锆和硝酸锌为原料,尿素为助燃剂,采用微波闪速法合成纳米ZrO2/ZnO复合材料,研究了纳米ZrO2/ZnO复合材料分别对甲基橙和罗丹明B的光催化降解性能。结果表明,在紫外光条件下,纳米ZrO2/ZnO复合材料光催化降解甲基橙效果明显优于罗丹明B。