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41.
Jong‐Woon Ha Yuntae Kim Jeongkyun Roh Fei Xu Jong Il Park Jeonghun Kwak Changhee Lee Do‐Hoon Hwang 《Journal of polymer science. Part A, Polymer chemistry》2014,52(22):3260-3268
New low‐temperature curable organic/inorganic hybrid polymers were designed and synthesized as gate dielectrics for organic thin‐film transistors (OTFTs). Allyl alcohols were introduced to polyhedral oligomeric silsesquioxane (POSS) via hydrosilyation to produce an alcohol‐functionalized POSS derivative (POSS‐OH). POSS‐OH was then reacted with hexamethoxymethylmelamine at carrying molar ratios at 80 °C in the presence of a catalytic amount of p‐toluenesulfonic acid to give highly cross‐linked network polymers (POSS‐MM). The prepared thin films were smooth and hard after the thermal cross‐linking reaction and had very low leakage currents (<10?8 A/cm2) with no significant absorption over the visible spectral range. Pentacene‐based OTFTs using the synthesized insulators as gate dielectric layers had higher hole mobilities (up to 0.36 cm2/Vs) than a device using thermally cross‐linked poly(vinyl phenol) and melamine as the gate dielectric layer (0.18 cm2/Vs). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3260–3268 相似文献
42.
The diastereomeric isomerization of the ZE isomers of (2Z, 2′E)-2,2′-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives were examined by 1H NMR spectroscopy in various organic solvents. In non-polar solvents, such as benzene, THF, and chloroform, the ZE isomers of these molecules equilibrated into a mixture of ZE/EE or ZE/EE/ZZ isomers with time, whereas the isomers were inert in polar organic solvents, such as acetone and DMSO. Theoretical calculations of the energies and dipole moments of the diastereomers in different media were performed using the Jaguar program. 相似文献
43.
Wookyoung Jang Do Yeon Kim Seok Joon Mun Jun Hee Choi Yoon Ho Roh Ki Wan Bong 《Journal of polymer science. Part A, Polymer chemistry》2022,60(11):1767-1777
Polyethylene glycol (PEG) hydrogel microparticles generated via stop-flow lithography can be utilized for efficient microparticle-based cell culture processes because of their high biocompatibility, the molecular diffusion capability in the gel structure, and the tunability of their shape and size. However, the typical functionalization process of PEG microparticles with cell-adhesion promoters has inevitable limitations, requiring additional linker molecules and the preconjugation of linkers to cell-adhesion promoters and microparticles. In this study, a simple and direct cell-adhesion promoter functionalization process of the PEG microparticles is presented by use of aza-Michael reaction between remnant unreacted acrylate groups in particles and amine groups in cell-adhesion promoters. On the basis of proposed process, particles are directly conjugated with poly-l -lysine (PLL), a typical cell-adhesion promoter that can electrostatically interact with cellular membranes, in a controllable manner. We demonstrate enhanced cell-adhesion capabilities of the particles along with the increased amount of conjugated PLL in the particles. Furthermore, to validate extended applicability, the particles are directly conjugated with Gly-Arg-Gly-Asp-Ser (GRGDS) peptides, in which RGD sequence is involved in the cell-adhesion behavior of extracellular matrix proteins, including fibronectin. The introduced GRGDS peptides increase the cell-adhesion capacity of the microparticles binding to integrin proteins in cellular membranes. 相似文献
44.
The (1)H and (13)C NMR spectra of dicondensed indolinobenzospiropyrans as precursors of thermo- and photochromic spiropyrans, DC1-DC5, were completely assigned. Especially, the (1)H assignment and coupling characteristics of the diastereotopic protons at the carbon-3 position of the benzopyran rings were achieved by conducting (1)H-(1)H COSY and nOe experiments. The dihedral angles (theta(1), theta(2) and theta(3)) calculated from the experimental values of the vicinal coupling constants ((3)J) of DC5 are in good agreement with the observed values in the solid state. All of the carbons in the DC dye molecules were investigated through a combination of heteronuclear 2D-shift correlation spectroscopy (HETCOR) and DEPT135. 相似文献
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Triphasic nanocolloids, that is, nanocolloids with three distinct compartments, were successfully produced by use of electrified co-jetting. Simultaneous manipulation of the three parallel liquid with laminar flows yielded a liquid droplet with three interfaces between the jetting liquids. Under a high electric potential, a single liquid jet was produced from the triple point of the droplet. Separation between the phases was maintained throughout the jetting process and resulted in triphasic nanocolloids. Poly(ethylene oxide), poly(acrylic acid), and poly(acrylamide-co-acrylic acid) solutions were used and verified to be compatible with the process. Fluorescent-labeled biomolecules were selectively incorporated in each phase of the nanocolloids, and confocal laser scanning microscopy was employed for the characterization. Scanning electron microscopy results verified that the sizes of the colloids are in the range of nanocolloids. This simple and versatile technique to fabricate multicompartment nanocolloids is expected to have great impact on drug delivery, molecular imaging, and smart displays. 相似文献
47.
The performance of an acoustic transducer is determined by the effects of many structural variables, and in most cases the influences of these variables are not linearly independent of each other. To achieve optimal performance of an acoustic transducer, we must consider the cross-coupled effects of its structural variables. In this study, with the finite-element method, the variation of the operation frequency and sound pressure of a flextensional transducer in relation to its structural variables is analyzed. Through statistical multiple regression analysis of the results, functional forms of the operation frequency and sound pressure of the transducer in terms of the structural variables were derived, with which the optimal structure of the transducer was determined by means of a constrained optimization technique, the sequential quadratic programming method of Phenichny and Danilin. The proposed method can reflect all the cross-coupled effects of multiple structural variables, and can be extended to the design of general acoustic transducers. 相似文献
48.
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50.
Yu.Ts. Oganessian A.V. Yeremin G.G. Gulbekian S.L. Bogomolov V.I. Chepigin B.N. Gikal V.A. Gorshkov M.G. Itkis A.P. Kabachenko V.B. Kutner A.Yu. Lavrentev O.N. Malyshev A.G. Popeko J. Roháč R.N. Sagaidak S. Hofmann G. Münzenberg M. Veselsky S. Saro N. Iwasa K. Morita 《The European Physical Journal A - Hadrons and Nuclei》1999,5(1):63-68
The reaction 48Ca+238U was investigated at the recoil separator VASSILISSA at the Flerov Laboratory of Nuclear Reactions, JINR Dubna, in attempts
to synthesize new isotopes of element 112. The experiments were performed at two beam energies resulting in excitation energies
of the compound nucleus of 33 and 39 MeV. The collected beam dose was 3.5 × 1018 and 2.2 × 1018, respectively. Two spontaneous fission events were observed at the lower beam energy, which tentatively were assigned to
the new neutron rich isotope 283112 produced in the reaction 238U(48Ca,3n)283112. The measured cross-section is (5.0+6.3
−3.2) pb and the half–life is (81+147
−32) s. No event was observed at the higher beam energy resulting in the upper cross–section limit of 7.3 pb.
Received: 12 October 1998 / Revised version: 12 January 1999 相似文献