排序方式: 共有23条查询结果,搜索用时 15 毫秒
1.
Pamela Twu Jared L. Anderson Timothy W. Stephens Anastasia Wilson William E. Acree Jr. Michael H. Abraham 《Journal of solution chemistry》2013,42(4):772-799
Chromatographic retention data were measured for a wide range of organic solutes on 1-butyl-1-methylpyrolidinium tris(pentafluoroethyl)trifluorophosphate ([BMPyrr]+[FAP]?), 1-butyl-1-methylpyrrolidinium triflate, ([BMPyrr]+[Trif]?), and 1-methoxyethyl-1-methylmorpholinium tris(pentafluoroethyl)trifluorophosphate, ([MeoeMMorp]+[FAP]?), stationary phases at (323, 353 and 383) K. The measured retention factors were combined with published infinite dilution activity coefficient and gas-to-water partition coefficient data to yield gas-to-anhydrous ionic liquid (IL) and water-to-anhydrous IL partition coefficients. The three sets of partition coefficients were analyzed using the Abraham model. The derived Abraham model correlations describe the observed gas-to-IL (log10 K) and water-to-IL (log10 P) partition coefficient data to within average standard deviations of about 0.11 and 0.15 log10 units, respectively. 相似文献
2.
Yeong-Tarng Shieh Hong-Mao Wu Yawo-Kuo Twu Yi-Chang Chung 《Colloid and polymer science》2010,288(4):377-385
The dispersion of carbon nanotubes (CNT) in water of different pH and in chitosan aqueous solution of three acids, acetic
acid, formic acid, and hydrochloric acid, was investigated. Chitosan was soluble in water of pH ≤3 and could well disperse
untreated CNT and acid-treated CNT, both of which had poor dispersion in water of pH ≤3. With the presence of 0.1 wt% chitosan
in solution, particle sizes of the CNT dispersion were found to decrease with increasing COOH contents on the CNT. Particle
sizes of CNT, untreated and acid-treated, in the three acidic aqueous solutions were found to increase with increasing chitosan
contents in solutions. Among the three acids, hydrochloric acid gave the smallest particle size of the CNT dispersion. Without
chitosan, the dispersibility of the acid-treated CNT in aqueous solutions of three acids was in the order of acetic acid >
formic acid > hydrochloric acid. 相似文献
3.
Yeong‐Tarng Shieh Gin‐Lung Liu Yawo‐Kuo Twu Tzong‐Liu Wang Chien‐Hsin Yang 《Journal of Polymer Science.Polymer Physics》2010,48(2):145-152
Effects of carbon nanotubes (CNT) on the dynamic mechanical property, thermal property, and crystal structure of poly(L ‐lactic acid) (PLLA) were investigated. Dynamic mechanical analysis (DMA) found that CNT via grafting modification with PLLA (CNT‐g‐PLLA) could result in effective reinforcing effects. Tan δ of DMA found that CNT‐g‐PLLA was compatible with the PLLA matrix, giving a single Tg of the composite with a higher CNT‐g‐PLLA loading giving a higher Tg of the composite. Wide angle X‐ray diffraction (WAXD) data demonstrated that CNT could assist the disorder‐to‐order (α′‐to‐α) transition in PLLA crystals but did not lead to a more compact chain packing of the crystal lattice in PLLA composites than in pure PLLA. The equilibrium melting temperature (T) obtained from Hoffman‐Weeks plots were found to increase with increasing CNT‐g‐PLLA content. Small angle X‐ray scattering data revealed that thicknesses of crystal layer and amorphous layer of PLLA both decreased with increasing CNT contents. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 145–152, 2010 相似文献
4.
The mean squared torque on a molecule can be obtained from infra-red or Raman band moments, and provides a direct measure of the strength of the anisotropic intermolecular forces. The expression for the mean squared torque on a molecule of species α in a fluid mixture is given in terms of the intermolecular potential and the angular pair correlation functions. This relation is made tractable by introducing a perturbation expansion in powers of the anisotropic potential strength for the angular pair correlation functions. Monte Carlo calculations of the mean squared torque are presented for a liquid of linear molecules having dipolar, quadrupolar and anisotropic overlap interactions. Comparison of the perturbation expansion to second order with these ‘exact’ results shows good agreement for μ*=μ/(εσ3)1/2 and Q*=Q/(εσ5)1/2 values less than about 0·5, and for values of the dimensionless overlap constant |δ| less than about 0·2. Finally, experimental values of the mean squared torque for both pure and mixed liquids are compared to the Monte Carlo and to the perturbation theory results. 相似文献
5.
Chorng H. Twu 《Fluid Phase Equilibria》1984,16(2):137-150
Twu, C.H., 1984. An internally consistent correlation for predicting the critical properties and molecular weights of petroleum and coal-tar liquids. Fluid Phase Equilibria, 16: 137–150.The objective of this work was to use normal boiling points and specific gravities to develop simple but reliable and accurate methods for predicting the critical properties and molecular weights of petroleum and coal-tar liquids. The normal boiling points of the systems investigated range up to 1778 R and the specific gravities up to 1.436. This virtually covers the entire range of practical interest. The predictions of critical properties based on the above data show significant improvement over published correlations. 相似文献
6.
L. A. Bloomfield C. W. S. Conover Y. A. Yang Y. J. Twu N. G. Phillips 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,20(1):93-96
We have investigated the structures and properties of alkali halide cluster ions produced by laser vaporization of solid samples. In many alkali halide cluster ions, we observe the appearances of bulk-like characteristics even at sub-nanometer sizes:fcc crystalline structures (including surface terraces), ionic binding, and a susceptibility to common bulk defects such as F and H color-centers. To understand the origins of cluster structures, we have made calculations of ground state energetics, high-temperature molecular dynamics, and the electronic structure of clusters having excess electrons. 相似文献
7.
Yeong‐Tarng Shieh Yawo‐Kuo Twu Chean‐Cheng Su Rong‐Hsien Lin Gin‐Lung Liu 《Journal of Polymer Science.Polymer Physics》2010,48(9):983-989
Effects of carbon nanotubes (CNT) on the isothermal crystallization kinetics of poly(L ‐lactic acid) (PLLA) were quantitatively investigated using the Avrami equation and the secondary nucleation theory of Lauritzen and Hoffman. CNT via grafting modification with PLLA could well disperse in the PLLA matrix and give significantly enhanced crystallization rate and crystallinity of PLLA as analyzed by differential scanning calorimetry and polarized optical microscopy. Analysis of isothermal crystallization kinetics using the Avrami equation demonstrated that CNT significantly enhanced the bulk crystallization of PLLA. Analysis of spherulite growth kinetics using the secondary nucleation theory of Lauritzen and Hoffman found that CNT could expand the temperature range of the crystallization regime III of PLLA. Values of the nucleation constant (Kg) in crystallization regimes III and II of PLLA both increased with increasing CNT contents. The Kg III/Kg II ratios were found to be close to the theoretical value 2 but were not clearly found to depend on the CNT contents. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 983–989, 2010 相似文献
8.
9.
Pamela Twu Jared L. Anderson Dawn M. Stovall Shoshana Zhang Colleen Dai Amber Schmidt 《Physics and Chemistry of Liquids》2016,54(1):110-126
Gas–liquid chromatographic retention factors have been measured for 42 different organic probes on a 2-methoxyethyl(dimethyl)ethylammonium tris(pentafluoroethyl)trifluorophosphate, ([MeoeM2EAm]+[FAP]–), stationary phase capillary column at 323 and 353 K. The measured retention factors were combined with published gas-to-liquid partition coefficient data for solutes dissolved in ([MeoeM2EAm]+[FAP]–) and with published gas-to-water partition coefficient data to yield 107 gas-to-anhydrous ionic liquid and 105 water-to-anhydrous ionic liquid partition coefficients. Abraham model correlations for describing solute transfer into ([MeoeM2EAm]+[FAP]–) were derived from the three sets of experimental partition coefficient data. The derived correlations back-calculated the experimental gas-to-([MeoeM2EAm]+[FAP]–) and water-to-([MeoeM2EAm]+[FAP]–) partition coefficient data to within 0.13 and 0.15 log units, respectively. 相似文献
10.
J. D. Wynn R. F. Karlicek Jr. Y. Twu C. A. Burrus R. S. Tucker G. Raybon 《Fiber and Integrated Optics》2013,32(4):367-373
The fabrication and performance characteristics of coplanar contact etched mesa-buried heterostructure (EMBH) distributed feedback (DFB) lasers emitting at 1.3μm wavelength are described. The processing was designed such that the lasers could be evaluated as coplanar contact or conventional (top/bottom) contact devices. The threshold current was as low as 14mA and the 3dB small signal response was as high as 9.4 GHz. Both these properties showed negligible differences when the device was biased either coplanarly or conventionally. 相似文献