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ON THE STRUCTURE OF CONTACT BINARIES .4. HIGH-MASS MODELS
No full text[[abstract]]Interior models for zero-age contact binaries of high total mass are constructed on the basis of the contact discontinuity hypothesis. The contact discontinuity in systems with a total mass greater than about 4 solar masses is shown to occur on the side of the primary rather than the secondary. Results for two models, one with masses of 4 + 2 solar masses and the other with 8 + 4 solar masses, are presented, along with the properties of the corresponding single stars. These results indicate that the most significant change introduced by the contact configuration is the appearance of a convection zone beneath the contact discontinuity at the Roche lobe of the primary. A proof is given that zero-age main-sequence radiative stars in thermal equilibrium cannot be expanded to fill their Roche lobes in a contact binary.
--------------------------------------------------------------------------------[[fileno]]2010118010115[[department]]物理
GAS-DYNAMICS OF SEMIDETACHED BINARIES .2. VERTICAL STRUCTURE OF THE STREAM
No full text[[abstract]]The letter considers the three-dimensional dynamics of the stream in semidetached binaries undergoing Roche-lobe overflow. Results of an earlier communication are generalized to include the dynamic effects in the direction perpendicular to the orbital plane. It is found that the scale height of the stream characteristically exceeds its corresponding hydrostatic value by a significant factor because the inertia of the gas prevents it from responding instantaneously to the changing gravitational field. This effect is important for the interpretation of observations relating to stream-disk impacts in cataclysmic variables and in binary X-ray sources of low total mass.
--------------------------------------------------------------------------------[[fileno]]2010118010123[[department]]物理
GAS-DYNAMICS OF SEMIDETACHED BINARIES
No full text[[abstract]]The gas dynamics of semidetached binary systems is analyzed in the context of the Roche model. It is shown that the steady flow can be formulated in terms of a problem with multiple length scales if it is assumed that the contact component rotates synchronously and the flow occurs isothermally with the thermal speed being a small fraction of the relative orbital speed of the two stars. This concept and semianalytical methods are used to demonstrate that material escapes from the surface of the contact component in a highly anisotropic stellar wind, that the wind throttles into a narrow stream of material whose width is a function of the orbital separation and whose density is a function of the mass transfer rate and the relative orbital speed of the two stars, and that the stream results in the formation of a disk of material of prescribed size orbiting the detached component if the latter is smaller than a specified size.
--------------------------------------------------------------------------------[[fileno]]2010118010124[[department]]物理
NONLINEAR GASEOUS DENSITY WAVES AND GALACTIC SHOCKS
No full text[[abstract]]We follow the perturbations in the flow of interstellar gas which result from steady forcing by spiral gravitational fields of various strengths. The density response is quite nonlinear even if the amplitude of the spiral field maintained by the disk stars is only a small fraction of the basic axisymmetric field. An analytical study of the properties of slightly nonlinear flows yields certain results which are qualitatively similar to those found numerically for fully nonlinear flows. Galactic shocks arise naturally, indeed necessarily, if the strength of the underlying spiral gravitational field exceeds a certain critical value. The breadth of the zone of high gas compression depends critically on whether the Doppler-shifted phase-velocity of the stellar density wave is greater than or less than the “effective acoustic speed” of the gas. In the former case, very narrow compression zones result; in the latter, quite broad zones. This distinction may explain why some galaxies have narrow optical arms while others have broad optical arms. In addition, a certain range of values for the intrinsic frequency of the wave gives rise to ultra-harmonic reasonances which can introduce secondary compressions of the interstellar gas. This result may relate directly to the origin of the Carina spiral feature in our own Galaxy as well as to the phenomena of branches, spurs, and feathers which are often seen in external spiral galaxies.[[fileno]]2010118010129[[department]]物理
Rates of Adsorption of Metal Ions on Natural and Substituted Celluloses
No full text[[abstract]]The rates of adsorption of zinc and cobalt ions from ethyl ether solutions on a number of substituted celluloses have been studied. The data indicate that a chemical retention of the metals is superimposed on a physical adsorption. The retention depends on the nature of the functional groups of the cellulose, on the tempetature and the concentration of the solution, and on time. The amount of the metal ions physically adsorbed has been determined by measuring the uptake of diethylamine on celluloses previously treated with zinc or cobalt solutions. Applications of the results in chromatography are suggested.[[fileno]]2010311010001[[department]]化學
The Preparation and Structural Study of Nickel (II) Complexes of N,N'-(8-quinolyl)trimethylenediamines
No full text[[abstract]]A number of Ni(II) complexes of N,N′-bis(8-quinolyl)trimethylenediamines are synthesized both as perchlorate salts and neutral amino complexes. Substitutions on the 2 and 6 positions of the quinolyl ligands are introduced for various reasons concerning the structural studies. The structural informations are obtained by studies of the magnetic properties, electronic spectra and NMR spectra. Structural changes effected by acid/base property of the medium are followed by NMR spectroscopy.[[fileno]]2010311010023[[department]]化學
Stereochemical Nonrigidity in Six-Coordinate Monochelate Complexes via Polytopal Rearrangement
No full text[[abstract]]Analysis of the F-19, C-13, and P-31 NMR data for F2 activated SiC(t-Bu) = CHSiF2Fe(CO)3(phosphine) (phosphine = PMe3, PPh2Me,PPh3, and PEt3, for compounds 3-6, respectively) over a temperature range covering slow and fast exchange characterizes those complexes as stereochemically nonrigid on the NMR time scale. The activation parameters for the rearrangement process are DELTA-G double-ended daggar = 16.8, 15.0, 12.5, and 13.2 kcal/mol for complexes 3-6, respectively. The crystal and molecular structures of 3b and 5a were determined. The molecular structures are best described as distorted octahedra. The space group of both 3b and 5a is Pca2(1): a = 15.617 (3) angstrom, b = 8.161 (3) angstrom, c = 29.858 (4) angstrom, and Z = 8 for 3b; a = 17.409 (8) angstrom, b = 9.439 (2) angstrom, c = 17.332 (5) angstrom, and Z = 4 for 5a. The intramolecular ligand permutations are interpreted in terms of the "trigonal-twist" mechanism.[[fileno]]2010311010049[[department]]化學
Highly Efficient Red Phosphorescent Osmium (II) Complexes for OLED Applications
No full text[[abstract]]The nonionic, red-emitting complexes [Os(fppz)(2)L-2] (L = PPh2Me (1), PPhMe2 (2)) and [Os(bptz)(2)L-2] (L = PPh2Me (3)) were synthesized, showing highly intense red phosphorescent emission in CH2Cl2 solution at lambda(max) 617, 632, and 649 nm, respectively. The electroluminescent properties of these compounds on OLEDs showed promising device efficiencies required for future OLED applications.[[fileno]]2010311010081[[department]]化學
國立清華大學簡訊第840期
Get PDF[[abstract]]‧ 102 學年度第 1 學期書卷獎頒獎典禮
‧ 賀 核工所施純寬教授榮獲行政院原子能委員會放射性物料管理局放射性物料研究發展 傑出貢獻獎：個人獎
‧ 賀 核工所謝志威同學、周孫安同學、喻冀平教授、黃嘉鴻教授榮獲 TACT2013 國際薄膜 會議海報論文獎
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‧ 演講資訊─102 學年下學期－化學系 專題演講清單[[fileno]]JA02_2014_84
