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931.
932.
Hsuan‐Ming Huang I‐Chun Liu Ching‐Yu Chang Hung‐Chieh Tsai Chuan‐Hsiao Hsu Raymond Chien‐Chao Tsiang 《Journal of polymer science. Part A, Polymer chemistry》2004,42(22):5802-5810
A new method was developed for preparing polystyrene‐functionalized multiple‐walled carbon nanotubes (MWNTs) through the termination of anionically synthesized living polystyryllithium with the acyl chloride functionalities on the MWNTs. The acyl chloride functionalities on the MWNTs were in turn obtained by the formation of carboxyls via chemical oxidation and their conversion into acyl chlorides. The polystyrene‐functionalized MWNTs had good dispersion in common organic solvents, and this indicated good compatibility for the preparation of styrenic nanocomposite materials. The synthesis results and characterization data for the functionalized MWNTs, collected via Fourier transform infrared, thermogravimetric analysis, solid‐state NMR, and electron microscopy, are presented and discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5802–5810, 2004 相似文献
933.
Chun-Min Hung Yueh-Min Huang Ming-Shi Chang 《Nonlinear Analysis: Theory, Methods & Applications》2006
A hybrid evolutionary model is used to propose a hierarchical homology of protein sequences to identify protein functions systematically. The proposed model offers considerable potentials, considering the inconsistency of existing methods for predicting novel proteins. Because some novel proteins might align without meaningful conserved domains, maximizing the score of sequence alignment is not the best criterion for predicting protein functions. This work presents a decision model that can minimize the cost of making a decision for predicting protein functions using the hierarchical homologies. Particularly, the model has three characteristics: (i) it is a hybrid evolutionary model with multiple fitness functions that uses genetic programming to predict protein functions on a distantly related protein family, (ii) it incorporates modified robust point matching to accurately compare all feature points using the moment invariant and thin-plate spline theorems, and (iii) the hierarchical homologies holding up a novel protein sequence in the form of a causal tree can effectively demonstrate the relationship between proteins. This work describes the comparisons of nucleocapsid proteins from the putative polyprotein SARS virus and other coronaviruses in other hosts using the model. 相似文献
934.
Chien-Lun Hung Yi Sheng Yeh 《International Journal of Infrared and Millimeter Waves》2005,26(1):29-39
Overmoded coaxial waveguides have been used in coaxial gyrotrons as a key interaction structure. To achieve the required mode selectivity, the resistivity of the center conductor is properly chosen to damp unwanted modes. Considering attenuation due to conductor loss, this study employs the perturbational method to determine the propagation constants of higher-order modes in the coaxial waveguide. The validity of the theoretical model is confirmed by comparison with results obtained using the high-frequency structure simulator (HFSS). Moreover, the method proposed herein is applied to analyze the ohmic mode selection of the coaxial waveguide. 相似文献
935.
Hybrid microspheres of poly(methyl acrylate‐co‐divinylbenzene) (PMADVB) with a thin and porous nickel–phosphorus (Ni–P) alloy layer were prepared via suspension polymerization and electroless nickel plating. The characterization of pristine and nickel‐coated microspheres was carried out with a differential scanning calorimeter and a scanning electron spectroscope equipped with an energy‐dispersive system. The glass‐transition range of Ni–P‐coated PMADVB was broadened and extended in the higher temperature direction. This effect allowed the PMADVB network to embrace more diversified energy states of the segment motion, this being a desired feature for damping sound waves. The low‐frequency (100–1000‐Hz) sound absorption behavior of the microspheres was tested with a sound attenuation kit. Besides the testing of their low‐frequency damping performance, an investigation into the ultrasonic‐wave (~35 kHz) absorption feature of the microspheres was conducted through chemical means; that is, the attenuation to the ultrasonic wave with respect to the unprotective situation was assessed through the chemisorption extent of copper ions on a biomass adsorbent. The Ni–P deposition layer was found to augment the damping capacity of the polymer network. The alloy layer was determined to cause an expansion of the glass‐transition range of PMADVB and its wave‐scattering capability because this layer was made up of submicrometer metallic grains. In this work, the particulars of the metal–polymer interactions were associated with a core–shell structure. The metal outer layer was thought to create a spherical temperature field inside the PMADVB network, and concerted motions of the polymer segments resulted. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2710–2723, 2004 相似文献
936.
The mitigating effect of a water wall on the generation and propagation of blast waves of a nearby explosive has been investigated
using a numerical approach. A multimaterial Eulerian finite element technique is used to study the influence of the design
parameters, such as the water-to-explosive weight ratio, the water wall thickness, the air-gap and the cover area ratio of
water on the effectiveness of the water mitigation concept. In the computational model, the detonation gases are modelled
with the standard Jones–Wilkins–Lee (JWL) equation of state. Water, on the other hand, is treated as a compressible fluid
with the Mie–Gruneisen equation of state model. The validity of the computational model is checked against a limited amount
of available experimental data, and the influence of mesh sizes on the convergence of results is also discussed. From the
results of the extensive numerical experiments, it is deduced that firstly, the presence of an air-gap reduces the effectiveness
of the water mitigator. Secondly, the higher the water-to-explosive weight ratio, the more significant is the reduction in
peak pressure of the explosion. Typically, water-to-explosive weight ratios in the range of 1–3 are found to be most practical.
PACS 47.40.-x; 47.40.Nm; 02.60.Cb
This paper was based on work that was presented at the 19th Interna-tional Colloquium on the Dynamics of Explosions and Reactive
Sys-tems, Hakone, Japan, July 27 - August 1, 2003 相似文献
937.
In order to investigate the photochemical tuning capability of chiral monomers and polymers containing end-capped menthyl groups, a new series of chiral dopants was synthesized and added to commercially available nematic liquid crystals to induce cholesteric liquid crystal (LC) phases. The addition of chiral dopants with azo structure led to phototunability of the reflection colour of the LC cells. Photochromic variation of the LC cells due to photoisomerization of the azo compound was investigated. After photopolymerization of the monomers inside the cholesteric LC cells, the centre wavelength of the reflected band of the incident light was found to be fixed and the reflected bandwidth was broadened, resulting in a red shift. A schematic representation of both the photoisomerization of the azo dopants and its effect on variation of twisting pitches is proposed. Real image recording was performed using 365 nm UV through a mask with text. The top and side views of the morphological network structures of a fabricated cholesteric LC cell were investigated using scanning electron microscopy. The results of this investigation demonstrated that RGB reflected colours of LC cells can easily be achieved through the addition of the menthyl-containing synthesized chiral compounds to nematic LCs. The addition of synthesized AzoM helped further in recording the patterns onto cholesteric LC films using 365 nm UV exposure. 相似文献
938.
Yuan‐Jyh Lee Shiao‐Wei Kuo Wu‐Jang Huang Hung‐Yen Lee Feng‐Chih Chang 《Journal of Polymer Science.Polymer Physics》2004,42(6):1127-1136
The miscibility of a phenolic resin with polyhedral oligomeric silsesquioxane (POSS) hybrids and the specific interactions between them were investigated with Fourier transform infrared (FTIR) spectroscopy and wide‐angle X‐ray diffraction (WAXD). An analysis of the morphology and microstructure was performed with polarized optical microscopy and atomic force microscopy (AFM). The interassociation equilibrium constant between the phenolic resin and POSS (38.7) was lower than the self‐association equilibrium constant of pure phenolic (52.3) according to the Painter–Coleman association model. This result indicated that POSS was partially miscible with the phenolic resin. A polarized optical microscopy image of a phenolic/POSS hybrid material (20 wt % POSS) indicated that the crystals of POSS were arranged evenly in the phenolic matrix; the self‐assembled array of POSS crystals was also confirmed by AFM. This phenomenon was consistent with the FTIR spectroscopy and WAXD analyses. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1127–1136, 2004 相似文献
939.
Coordination of a bulky pyridinyl‐phosphine ( P?N ) ligand toward CuBr was investigated. However, this P?N donor behaves as a monodentate via the coordination of phosphine to form a bromide bridged dimeric [( P?N )Cu(μ‐Br)2Cu( P?N )], which was characterized by spectral and crystal structural analysis. It appeared that the “PCu(μ‐Br)2CuP” unit is planar with a short distance between Cu…Cu' [2.7585(9) Å]. The catalytic activity on Sonogashira coupling of phenylacetylene with aryl halides was studied. 相似文献
940.
In this paper, the necessary and sufficient conditions for the existence of cyclic 2q‐cycle and m‐cycle systems of the complete graph with q a prime power and 3 ≤ m ≤ 32 are given. © 2005 Wiley Periodicals, Inc. J Combin Designs 相似文献