Silicone-enriched surface of immersed polyurethane-POSS antifouling coating

Abstract

A series of waterborne polyurethane-polyhedral oligomeric silsesquioxane (WBPU-POSS) dispersions were synthesized. Different POSS contents were used to evaluate the effect of POSS content on silicone enrichment under both nonimmersed and immersed conditions. The impact of silicone enrichment under immersed conditions on antifouling properties was also evaluated. The structure of the WBPU-POSS coating was identified by FT-IR and ²⁹Si-NMR. X-ray photoelectron spectroscopy (XPS) analysis confirmed a silicone-enriched surface with a certain composition of the WBPU-POSS coating under both nonimmersed and immersed conditions. The mechanical properties, hydrophilicity and hydrolytic degradation of the coating all varied with POSS content. The long-term antifouling performance of immersed coatings depends on surface silicone enrichment, which was found to be above 0.0021?mole POSS content in WBPU-POSS coatings.     

Measurements of the oscillator strengths for the 6p7s (1/2,1/2)1 → 6pnp (1/2,3/2)2 Rydberg transitions of lead

We report experimentally determined oscillator strength distribution in the bound region of lead corresponding to the 6p7s (1/2, 1/2)₁ → 6pnp (1/2, 3/2)₂ (20 ≤ n ≤ 52) Rydberg transitions. The absolute value of the photoionization cross section from the 6p7s (1/2, 1/2)₁ excited state at the first ionization threshold 6p (²P_1/2) has been determined as 27 ± 4 Mb using the saturation absorption technique. The threshold value of the photoionization cross section is used to calibrate the oscillator strengths of the above mentioned Rydberg transitions. Moreover, oscillator strengths in the bound region smoothly connect with the differential oscillator strength density at the first ionization threshold, and verify the fundamental condition of quantum defect theory.     

Convective heat transfer and MHD effects on Casson nanofluid flow over a shrinking sheet

Current study examines the magnetohydrodynamic (MHD) boundary layer flow of a Casson nanofluid over an exponentially permeable shrinking sheet with convective boundary condition. Moreover, we have considered the suction/injection effects on the wall. By applying the appropriate transformations, system of non-linear partial differential equation along with the boundary conditions are transformed to couple non-linear ordinary differential equations. The resulting systems of non-linear ordinary differential equations are solved numerically using Runge-Kutta method. Numerical results for velocity, temperature and nanoparticle volume concentration are presented through graphs for various values of dimensionless parameters. Effects of parameters for heat transfer at wall and nanoparticle volume concentration are also presented through graphs and tables. At the end, fluid flow behavior is examined through stream lines. Concluding remarks are provided for the whole analysis.     

IRAS investigation of a catenane adsorption on Au(1 1 1)

The adsorption of a benzylic amide [2]catenane on a Au(1 1 1) single crystal has been studied using infrared reflection absorption spectroscopy. The evolution of the infrared spectra during catenane deposition at different temperatures of the gold substrate (300 and 90 K) has been compared. Evidence of the catenane deformation upon chemisorption have been found at 300 K only. At 90 K the catenane is weakly adsorbed without any deformation.     

Fenofibric acid

Unlike the related fenofibrate molecule [Henry, Zhang, Gao & Bruckner (2003). Acta Cryst. E 59 , o699–o700], fenofibric acid {systematic name: 2‐[4‐(4‐chlorobenzoyl)phenoxy]‐2‐methylpropanoic acid}, C₁₇H₁₅ClO₄, contains a carboxylic acid moiety instead of an ester moiety. This polar moiety plays an important role in the formation of a rare acid‐to‐ketone hydrogen‐bond‐type packing interaction. The lack of an isopropyl group in fenofibric acid aligns the carboxyl group on the same side as the ketone carbonyl group; this conformation may play an important role in discrimination between the acid and the fenofibrate mol­ecule in molecular recognition.     

怀孕期头发中一些元素含量的变化趋势

用同步辐射激发X射线荧光分析,对11个产妇怀孕期间头发内一些元素含量的变化趋势进行了测量,在各自对比的基础上,得到了一些结果。     

阳离子表面活性剂三甲基溴化铵与硝酸铵相互作用的表面和热力学研究

本文系统研究了阳离子表面活性剂三甲基溴化铵和硝酸铵盐的表面现象和自聚集行为. 采用电导法和表面张力法研究在不同温度下阳离子表面活性剂三甲基溴化铵的表面性质和热力学性质. 通过表面张力测定得到临界胶束浓度、吸附自由能、胶束化的自由能、最小分子面积和表面过量浓度. 该研究表明,胶束化过程是自发放热反应. 电导测定结果确定了临界胶束浓度、电离程度和反离子结合度. 加入硝酸铵盐至表面活性剂溶液后,临界胶束浓度降低,电离程度和反离子结合度增加,更加有利于胶束化过程的自发. 该研究对进一步理解电解质和表面活性剂之间相互作用具有重要意义.     

Bioactive Heteroleptic Bismuth(V) Complexes: Synthesis,Structural Analysis and Binding Pattern Validation

Heteroleptic triorganobismuth (V) complexes of general formula, R₃Bi(OOCR')₂ ( 1 – 7 ), where R = C₆H₅ ( 1 – 3 ), p‐CH₃C₆H₄ ( 4 – 7 ) and R' = 3,5‐Cl₂C₆H₃ ( 1 , 5 ); 3,4,5‐(OCH₃)₃C₆H₂ ( 2 , 6 ); 3‐CH₃C₆H₄ ( 3 , 7 ); 2‐OH‐3‐OCH₃C₆H₃ ( 4 ) have been synthesized and fully characterized by FT‐IR, ¹H &¹³C NMR spectroscopy, single crystal X‐ray crystallography and elemental analysis. The molecular geometry observed for the compounds is predominantly distorted trigonal bipyramidal, the fact which was subsequently authenticated through X‐ray analyses for ( 1 – 4 ). All the synthesized compounds have been bio‐assayed for antileishmanial (Leishmania tropica KWH23) and Jack beans urease inhibitory activity, and human Lymphocytes were used to measure the general toxicity. Of these, ( 4 ) proved to be highly effective against the target species (Leishmania tropica KWH23), while being non‐toxic towards the mammalian cells at levels below 0.74 μgmL^?1, making it highly promising drug candidate. The high activities for ( 2 , 4 , and 6 ) against Jack beans Urease as compared to the reference standard demonstrate their significance in searching of therapeutic agents in future programs. The significant binding score of ( 2 & 4 ) against H. pylori in molecular docking studies further revealed their importance in future drug discovery processes.