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991.
Yong Seok Lee Young Chan Bae 《Journal of polymer science. Part A, Polymer chemistry》2000,38(22):4128-4136
A new model has been proposed that takes into account the specific interaction between nematic liquid crystal and polymer. A generalized lattice fluid model was employed to describe the specific interaction between liquid crystal and polymer. The proposed model postulates that a specific interaction between dissimilar components in a mixture has both an energetic and an entropic component. A degeneracy parameter and an interaction parameter are also discussed, followed by a comparison of the experimental data to the model. The results show that that a specific interaction plays an important role in the phase behaviors of the given systems. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4128–4136, 2000 相似文献
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993.
We propose a stress model to account for the thermal stress caused by a mismatch of isobaric expansivity, solvent evaporation, and imidization. The evaporation strain term is given as functions of a viscosity, and solvent weight fraction. The proposed model is in very good agreement with experimental data and gives useful information about the analysis of the thermal stress caused in polymeric films. 相似文献
994.
Chi‐Ming Chan Lin Li Kai‐Mo Ng Jianxiong Li Lu‐Tao Weng 《Macromolecular Symposia》2000,159(1):113-122
Two series of polyethers were synthesized by the polymerization of 1, n‐dibromoalkane (n = 4, 6, 8, 10, 12, 14 and 18) with bisphenol‐A (BA) and 4, 4'‐(hexafluoroisopropylidene) diphenol‐A. The length of the flexible aliphatic segment changes from 4 Å to 21 Å (corresponding to 4 to 18 CH2 groups). X‐ray photoelectron spectroscopy (XPS), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and atomic force microscopy (AFM) were used to characterize the surfaces of the polyethers. The influence of the length of the flexible aliphatic segments on the surface composition of the BA and 6FBA polyethers was investigated. The intensity ratios of the characteristic SIMS peaks of the flexible segments to those of the rigid segments were related to the length of the flexible segments and the XPS results confirmed that the SIMS intensity ratios can be used to determine the surface compositions. AFM was utilized to investigate the crystallization process of the BA polymer with n = 8. The appearance of nuclei, the generation of primary lamellae and the formation of spherulites were observed dynamically. Nuclei appeared first as 10 nm dots, some disappeared and a few could grow into lamellae. The lamellae that developed from the nuclei bred more lamellae, which in turn induced secondary nucleation and branching of lamellae and finally led to a spherical appearance. 相似文献
995.
Yongkwan Dong Hoseop Yun Chan Sun Park Won Koo Lee Hyun‐Joon Ha 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(12):o659-o660
In the title compound, C13H14BN3O, the aziridine ring is an almost equilateral triangle, the C—C distance being slightly shorter than the C—N distances, probably because of the dative B—N bond. The five‐membered ring, composed of two C atoms and N, B and O atoms, is fused with the aziridine ring to form a six‐membered ring with a chair conformation. 相似文献
996.
997.
998.
The chiral phosphorus derivatizing agent (CDA) 1 was prepared from optically pure (S)‐1,1‐bis‐2‐naphthol. It was first used in the determination of the enantiomeric excess of chiral alcohols and amines by means of 31P NMR spectroscopy. It showed that, for the chiral aromatic alcohols, no apparent kinetic resolution was noted and good base‐line separation was observed. Furthermore, the chemical shift difference (Δδ) of 31P NMR spectroscopy was much larger than those determined by the use of other chiral phosphorus derivatizing agents reported previously. However, for aliphatic alcohols, it showed not only obvious kinetic resolutions but incomplete base‐line separation. Moreover, we also found that the use of CDA 1 was suitable for the determination of enantiomeric excess of chiral primary amines. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:93–95, 2002; DOI 10.1002/hc.10018 相似文献
999.
Synthesis of Unsymmetric Bipyridine–PtII–Alkynyl Complexes through Post‐Click Reaction with Emission Enhancement Characteristics and Their Applications as Phosphorescent Organic Light‐Emitting Diodes 下载免费PDF全文
Dr. Yongguang Li Dr. Daniel Ping‐Kuen Tsang Dr. Carmen Ka‐Man Chan Dr. Keith Man‐Chung Wong Dr. Mei‐Yee Chan Prof. Dr. Vivian Wing‐Wah Yam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13710-13715
Two unsymmetric bipyridine–platinum(II)–alkynyl complexes have been synthesised by a post‐click reaction. These metal complexes are found to exhibit emission enhancement properties. The photoluminescence quantum yield can be significantly increased from 0.03 in solution to 0.72 in solid‐state thin films. Efficient solution‐processable organic light‐emitting diodes have been fabricated by utilizing these complexes as phosphorescent dopants. A high external quantum efficiency of up to 5.8 % has been achieved. 相似文献
1000.
Prabal Datta Barua Wai Yee Chan Sengul Dogan Mehmet Baygin Turker Tuncer Edward J. Ciaccio Nazrul Islam Kang Hao Cheong Zakia Sultana Shahid U. Rajendra Acharya 《Entropy (Basel, Switzerland)》2021,23(12)
Optical coherence tomography (OCT) images coupled with many learning techniques have been developed to diagnose retinal disorders. This work aims to develop a novel framework for extracting deep features from 18 pre-trained convolutional neural networks (CNN) and to attain high performance using OCT images. In this work, we have developed a new framework for automated detection of retinal disorders using transfer learning. This model consists of three phases: deep fused and multilevel feature extraction, using 18 pre-trained networks and tent maximal pooling, feature selection with ReliefF, and classification using the optimized classifier. The novelty of this proposed framework is the feature generation using widely used CNNs and to select the most suitable features for classification. The extracted features using our proposed intelligent feature extractor are fed to iterative ReliefF (IRF) to automatically select the best feature vector. The quadratic support vector machine (QSVM) is utilized as a classifier in this work. We have developed our model using two public OCT image datasets, and they are named database 1 (DB1) and database 2 (DB2). The proposed framework can attain 97.40% and 100% classification accuracies using the two OCT datasets, DB1 and DB2, respectively. These results illustrate the success of our model. 相似文献