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201.
Shovsky A Bijelic G Varga I Makuška R Claesson PM 《Langmuir : the ACS journal of surfaces and colloids》2011,27(3):1044-1050
Adsorption properties of stoichiometric and nonstoichiometric polyelectrolyte complexes (PECs) have been investigated by means of dual polarization interferometry (DPI) and X-ray photoelectron spectroscopy (XPS). Poly(sodium styrenesulfonate) (NaPSS) of molecular weight 4300 g/mol was used as polyanion, and two bottle-brush copolymers possessing different molar ratios of the cationic segment methacryloxyethyltrimethylammonium chloride (METAC) and the nonionic segment poly(ethylene oxide) methyl ether methacrylate (PEO(45)MEMA) were used as polycations. They are referred to as PEO(45)MEMA:METAC-25 and PEO(45)MEMA:METAC-50, where the last digits denote the mol % of charged main-chain segments. The time evolution of the adsorbed amount, thickness, and refractive index of the PEC layers were determined in aqueous solution using DPI. We demonstrate that cationic, uncharged, and negatively charged complexes adsorb to negatively charged silicon oxynitride and that maximum adsorption is achieved when small amounts of PSS are present in the complexes. The surface composition of the adsorbed PEC layers was estimated from XPS measurements that demonstrated very low content of NaPSS. On the basis of these data, the PEC adsorption mechanism is discussed and the competition between PSS and negative surface sites for association with the cationic polyelectrolyte is identified as a key issue. 相似文献
202.
We developed an analysis method to evaluate the size and shape of particles of eye shadow cosmetics by applying the scanning electron microscopy (SEM) combined with the energy-dispersive spectroscopy (EDS). Backscattered electron (BE) and X-ray mapping images from the SEM-EDS measurements were interpreted to identify the size and shape of powder particles according to different factors such as 9 size and 5 shape indices established in this work. By using the developed method, we could classify the inorganic and organic particles of the eye shadow powder by composition, which can contribute to improving the product quality. 相似文献
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205.
Dr. Sebastijan Ričko Dr. Joseph A. Izzo Prof. Dr. Karl Anker Jørgensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(67):15727-15732
The use of pseudo enantiomers is a well-known method of achieving products of complementary stereochemistry. Only rarely can different enantiomers of a product be accessed without modulation of the catalyst. Recently, a system was reported wherein two different enantiomers of spirocycles were obtained by a cascade reaction of unsaturated pyrrolin-4-ones with mercaptoacetaldehyde catalyzed by a single optimized cinchona alkaloid squaramide-derived organocatalyst. It was originally proposed that the E/Z geometry of the unsaturated pyrrolin-4-one dictated the stereochemistry of the spirocycle product, but this was not investigated further. In the present work, we have investigated the nature of a pseudo-enantiomeric organocatalyst conformation applying density functional theory calculations for investigating the transition states for the reaction. Furthermore, the influence of the double-bond geometry of the pyrrolin-4-one has been studied beyond what is possible to test experimentally. The results provide a greater understanding for this class of reactions that may be applicable in future methodology development. 相似文献
206.
Ri Kwangchol Han Wonjin Pak Choljun Kim Kumchol Yun Cholil 《Nonlinear dynamics》2021,104(4):3347-3364
Nonlinear Dynamics - In this paper, the internal resonance phenomena of a composite shaft-disk system with multi-degrees-of-freedom are analyzed. The force caused by the unbalanced mass of the disk... 相似文献
207.
Hyperchaotic behaviours and controlling hyperchaos in an array of RCL-shunted Josephson junctions 下载免费PDF全文
This paper deals with dynamical behaviours in an array composed of two resistive-capacitive-inductive-shunted (RCL-shunted) Josephson junctions (RCLSJJs) and a shunted resistor. Numerical simulations show that periodic, chaotic and hyperchaotic states can coexist in this array. Moreover, a scheme for controlling hyperchaos in this array is presented by adjusting the external bias current. Numerical results confirm that this scheme can be effectively used to control hyperchaotic states in this array into stable periodic states, and different stable periodic states with different period numbers can be obtained by appropriately choosing the intensity of the external bias current. 相似文献
208.
Lee NY Lim JR Lee MJ Kim JB Jo SJ Baik HK Kim YS 《Langmuir : the ACS journal of surfaces and colloids》2006,22(21):9018-9022
Here, we introduce a nanopatternable hydrophilic composite elastomer highly desirable for both nanostructure patterning via solvent-assisted micromolding (SAMIM) and microcontact printing of polar inks. This composite precursor is prepared by blending two UV-curable materials, Norland Optical Adhesives (NOA) 63 and poly(ethylene glycol) diacrylate (PEGDA), in an appropriate ratio; upon UV polymerization, a nanopatternable elastomer with preferential permeability both to aqueous and organic solvent is fabricated. Using this composite mold, nanoscale SAMIM of poly(4-vinylpyridine) (P4VP) and microcontact printing of a polar biomolecule, bovine serum albumin (BSA), was successfully demonstrated, paving the way for facile and efficient reproduction of various nanopatterns and a biomolecule-printed array platform. 相似文献
209.
证明了 Burr分布和 Frechét分布的记录值序列的部分和是渐进对数正态的 ,从而解决了文[2 ]中的一个悬而未决的问题 相似文献
210.
It has been known since the pioneering works of Wim Vervaat in the early 70"s that the appropriately normalized Vervaat process asymptotically behaves like one half times the squared empirical process. In this paper we present a survey of the results concerning various distances between the Vervaat process and one half times the squared empirical process. In particular, the pointwise, Lp-, and sup-distances between these two processes are given full consideration. 相似文献