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排序方式: 共有552条查询结果,搜索用时 981 毫秒
71.
Basel F. Abu-Sharkh Adam M. Giri Ibnelwaleed A. Hussein 《European Polymer Journal》2004,40(6):1177-1182
Microstructure of linear low-density polyethylene (LLDPE) with linear high-density polyethylene (HDPE) is investigated by molecular dynamics (MD) simulation. The branch content of LLDPE was varied from 10 to 60 branches/1000 C. An equimolar mixture of each of the two polymers is simulated in the NVT ensemble at 500 K and at average experimental densities of the two polymer melts. Initially, chains of LLDPE and HDPE were completely mixed and evolution of conformations with time was monitored. The blends were found to microphase separate when the branch content of LLDPE exceeded 30 branches/1000 C. At 40 branches/1000 C, the two polymers displayed partial microphase separation and complete microphase separation was observed at 60 branches/1000 C. Substantial short-range order and mismatch of molecular conformations is observed in the microphase-separated systems. 相似文献
72.
Functionalization of gold cysteamine (Au? CA) self‐assembled monolayer with 4‐formylphenylboronic acid (BA) via Schiff's base formation, through in situ method to fabricate Au‐CA‐BA electrode is presented and described. The fabricated electrode was used as a novel sensor for accumulation and determination of dopamine (DA). The accumulation of DA as a diol on the topside of Au‐CA‐BA as a Lewis acid, was performed via esterification (Au? CA? BA? DA), and followed for determination of DA. Functionalization, characterization, and determination steps were probed by electrochemical methods like cyclic voltammetry and electrochemical impedance spectroscopy. The data will be presented and discussed from which a new sensor for DA is introduced. 相似文献
73.
分析了平均孤子传输系统中用于能量补偿的掺铒光纤放大器增益超过或低于理想值时平均孤子传输特性的劣化,提出并证明了利用工作在饱和区的掺铒光纤放大器可实现平均孤子在能量补偿偏离时自稳定传输,讨论了这一措施的可行性及适用范围。 相似文献
74.
Investigation of the self association of higher fatty alcohols and acids on chromatographic sorbents
Summary Three different sorbents, one with high activity (silica gel), the second with medium activity (cellulose powder) and the third having low activity (chromatographic paper) were compared in respect of their usefulness for the evaluation of the self association of selected higher fatty alcohols and acids. The obtained results are correlated with IR spectroscopic data and theoretical considerations. 相似文献
75.
Ken-ichi Maruyama 《Transactions of the American Mathematical Society》2006,358(6):2335-2351
We study a filtration on the group of homotopy classes of self maps of a compact Lie group associated with homotopy groups. We determine these filtrations of and completely. We introduce two natural invariants and defined by the filtration, where is a prime number, and compute the invariants for simple Lie groups in the cases where Lie groups are -regular or quasi -regular. We apply our results to the groups of self homotopy equivalences.
76.
Hybrid nanofilms from zinc-peroxide/poly(acrylamide) (ZnO2/PAAm) and zinc-peroxide/poly(N-isopropyl-acrylamide) (ZnO2/PNIPAAm) were prepared using the photopolymerization procedure. The thin layers were prepared by the combination of the Layer-by-Layer (LbL) self-assembly method and photopolymerization using UV light in every step of the procedure. The hybrid multilayer films consisting of layers of zinc peroxide nanoparticles and hydrogel alternating in a sandwich-like fashion with thicknesses of 65-246 nm. The chemical structures of the hybrid films were investigated by FTIR spectroscopy, their morphology was studied by atomic force microscopy (AFM). The build up of the films was studied by measuring the optical reflection spectrum, and we have calculated the refractive index and layer thickness of the hybrid layers using simulating software. The adsorption properties of the ZnO2/hydrogel nanohybrid composite networks were investigated by measuring water and ethanol vapour adsorption by a quartz crystal microbalance (QCM). It was established that on partially hydrophobic ZnO2/PNIPAAm hybrids the adsorbed amounts were lower, against the hydrophilic ZnO2/PAAm film the vapour amount was higher. These results correspond to those of the bulk gel swelling results. 相似文献
77.
Qi Wang Jinghui Yang Weiwei Yao Ke Wang Rongni Du Qin Zhang Feng Chen Qiang Fu 《Applied Surface Science》2010,256(20):5843-4934
Self-assembly of block copolymer is an effective strategy to prepare periodic structures at nanoscale. In this paper an unique and very simple method to prepare inorganic silica nanopattern is demonstrated from self-assembling of poly(styrene-block-dimethylsiloxane) (PS-b-PDMS) on the surface of silicon wafer. To simplify the patterning process, at first we obtain highly ordered PDMS microdomains, which are covered with PS layer by controlling solvent vapor annealing conditions. Following exposure to UV/O3 irradiation, nanopatterned surface consisting of silicon oxide is fabricated directly via selectively etching PS phase and converting PDMS phase into silicon oxide. As tuning the composition of the block copolymer, hexagonally packing dot and straight stripe pattern can be obtained. Finally, the time evolution from spheres morphology to aligned long cylinders is discussed. These results hold promise for nanolithography and the fabrication of nanodevices. 相似文献
78.
79.
Wenxin Lin Jianqiu Gong Huizhong Zhou Yijia Wang Linhui Gao Hongliang Zhu Jianjun Chen 《无机化学与普通化学杂志》2019,645(20):1215-1219
In this work, two types of chromophore i.e. the pyrromethene and perylene families dyes were doped into elastic polymeric host materials based on polydimethylsiloxane (PDMS), which had been widely employed in various applications. The solubilities, spectroscopic and laser properties of these dyes doped into PDMS matrices were systematically investigated. Tunable laser output with high conversion efficiencies and low laser thresholds were observed and calculated. The laser longevity of pyrromethene dyes doped in PDMS matrices could exceed 1 × 105 pulses through a fast self‐recovery on the laser output with the elapse of aging time. The efficient and stable laser output of the dopants and the flexibility of the PDMS host provided the feasibility of such gain media as mechanically tunable laser sources, which might be employed as cost‐effective components on integrated bio‐chips. 相似文献
80.
《无机化学与普通化学杂志》2018,644(3):142-148
Three diacylthioureas 1,4‐C6H4[C(O)NHC(S)NHAr]2 (Ar = 2,6‐iPr2C6H3) ( L1 , 1 ), 1,3‐C6H4[C(O)NHC(S)NHAr]2 ( L2 , 2 ), and 1,3‐C6H4[C(O)NHC(S)NHAr′]2 (Ar′ = 2,6‐Me2C6H3) ( L3 , 3 ) were synthesized and characterized. The CuI complexes from the reactions of bipodal ligands Ln with CuX (X = Cl, Br, I) were structurally investigated by single‐crystal X‐ray diffraction methods. Treatment of L1 with CuX gave the metallamacrocyclic complexes ( L1 CuX)2 [X = Cl ( 4 ), Br ( 5 ), I ( 6 )] with the ligand to metal in a ratio of 2:2, where both sulfur and halide anions function as terminal substituents. In contrast, when L2 or L3 was reacted with CuBr, the two Ln ligands coordinate to four copper atoms each in a bridging and terminal fashion to yield [ Ln (CuBr)2]2 [n = 2 ( 7 ), 3 ( 8 )]. The obtained S4Cu4Br4 core contains all four bromide anions in bridging positions. The reaction of L3 with CuX (X = Cl, I) gave the 3:3 trinuclear complexes ( L3 CuX)3 [X = Cl ( 9 ) I ( 10 )], interconnected by halide bridges. The obtained diacylthioureas ( 1 – 3 ) and their CuI complexes ( 4 – 10 ) were also characterized by elemental analysis, FT‐IR, 1H and 13C NMR spectroscopy. 相似文献