Showing papers by "National Tsing Hua University published in 1979"
TL;DR: In this article, a modified α-test method was adopted to examine the new type zeolite ZSM-5 which was synthesized in our laboratory and the results show that HZ SM-5 has superb activity on n-hexane cracking, lower aging rate, and better steam stability than other zeolate-type catalysts.
64 citations
TL;DR: In this paper, a backscattering technique was used to study the reaction of titanium thin films with silicon and with SiO 2 in the temperature range 500-600°C.
46 citations
TL;DR: This paper results from an attempt to unify several different file system design theories and shows that for both partial and best match queries, the file systems exhibit a common characteristic: similar records are grouped together.
Abstract: This paper results from an attempt to unify several different file system design theories. We define a term "partial match pattern" and show that in order to produce file systems optimal with respect to partial match patterns, both the multikey hashing (MKH) method [16] and the multidimensional directory (MDD) method [11] must be in such a form that the number of subdivisions is the same for all domains of keys. We show the conditions for the string homomorphism hashing (SHH) method [15], the MKH method, and the MDD method to be equivalent to one another. We define the so-called Cartesian product files and show that if all records are present, the records in a Cartesian product file form a shortest spanning path in which the Hamming distance between every pair of consecutive records is 1. Thus the SHH method, the MKH method, the MDD method, and the multikey sorting (MKS) method [10] are linked together. Finally, we show that for both partial and best match queries, the file systems exhibit a common characteristic: similar records are grouped together.
44 citations
TL;DR: In this paper, a modified form of local gauge invariance and minimal coupling was used to obtain a dynamic torsion theory which allows propagation of torsions in vacuo.
Abstract: Considering a modified form of local gauge invariance and minimal coupling, Hajman, Rosenbaum, Ryan, and Shepley obtained a dynamic torsion theory which allows propagation of torsion in vacuo. In this theory, the torsion is determined by the gradient of a scalar field $\ensuremath{\varphi}$. For the Sun, $\ensuremath{\varphi}=0.67\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}U$ where $U$ is the Newtonian potential. In this field, test bodies with different electromagnetic energy contents behave differently. For aluminum and gold (or platinum), the gravitational accelerations would differ by $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}{\stackrel{\ensuremath{\rightarrow}}{\ensuremath{
abla}}}^{U}$. This implication disagrees with the null experiments of precisions ${10}^{\ensuremath{-}11}{\stackrel{\ensuremath{\rightarrow}}{\ensuremath{
abla}}}^{U}$ and ${10}^{\ensuremath{-}12}{\stackrel{\ensuremath{\rightarrow}}{\ensuremath{
abla}}}^{U}$ performed respectively by Roll, Krotkov, and Dicke and by Braginsky and Panov.
32 citations
TL;DR: In this article, the continuous-slowingdown-approximation range and range straggling for electrons with energies? 10 keV in Al, Au, Ag, and Cu are calculated.
Abstract: The continuous-slowing-down-approximation range and range straggling for electrons with energies ? 10 keV in Al, Au, Ag, and Cu are calculated. The mean energy loss per unit pathlength, or the stopping power, is described by a statistical electron gas model. A correction to the stopping power due to the Z31 effect is included. Comparisons of the calculated CSDA ranges with experimental data are made.
21 citations
TL;DR: In this paper, a mathematical model which is based on different charge transfer rates between the following two reactions was formulated to describe the behaviour of a Cu/CuSO4 system under pulsed current conditions on a rotating disc electrode.
Abstract: The investigation is concerned with the drop of current efficiency (CE) of copper deposition under pulsed current conditions. A mathematical model which is based on different charge transfer rates between the following two reactions,
$$Cu^{2 + } + e \to Cu^ + $$
(1)
and
$$Cu^ + + e \to Cu$$
(2)
has been formulated to describe the behaviour of a Cu/CuSO4 system under pulsed current conditions on a rotating disc electrode. The results indicate that the CE drops continuously as the difference between the exchange current densities of the two reactions increases. The exchange current densities of Reactions 1 and 2 were estimated to be 0.034 mA cm−2 and 0.024 mA cm−2, respectively. Prediction of CE using the mathematical model agreed to within 3.5% with experimental data over a range 80.4–93.7%.
20 citations
TL;DR: In this article, the authors analyzed the stability and multiplicity of autocatalytic reactions of the type A + R R R + R with overall rate expression in a continuous stirred-tank reactor (CSTR) in a rigorous way.
Abstract: Concentration multiplicity and stability for autocatalytic reactions of the type A + R R + R with overall rate expression in a continuous stirred-tank reactor (CSTR) is analyzed in a rigorous way in this paper. Important parameters for multiplicity criteria are reaction orders m and n, dimensionless space time Θ, and the ratio P of feed concentration of R to that of A. Necessary conditions for the system to have multiple exit concentrations (conversions) are defined in the (m, n, P) space. Multiplicity is guaranteed by limiting the dimensionless space time in a proper range in addition to the necessary conditions. Stability analysis shows that there is no periodic oscillation for the system. The upper and lower steady states of multiple solutions are both asymptotically stable. A unique steady state is globally stable.
On analyse d'une maniere rigoureuse, dans le present travail, la multiplicite et la stabilite des concentrations dans le cas de reactions auto-catalytiques du type A + R R + R, qui se produisent dans un reacteur continu et a reservoir agite (CSTR) et impliquant l'expression globale de vitesse Les parametres importants pour les criteres de multiplicite des concentrations sont: (a) les ordres de reaction m et n; (b) l'espace-temps sans dimensions (θ) et le rapport P entre la concentration d'alimentation de R et celle de A. Les conditions requises pour que le systeme ait des concentrations multiples a la sortie (transformations) sont definies dans l'espace (m, n, P). La multiplicite des concentrations est assuree en restreignant l'espace-temps sans dimensions sur un domaine approprie, en plus des conditions necessaires. L'analyse de la stabilite indique qu'il n'existe aucune oscillation periodique pour le systeme. Les regimes permanents superieurs et inferieurs des solutions multiples sont stables d'une maniere asymptotique. Un seul regime permanent est totalement stable.
20 citations
18 citations
TL;DR: In this article, the cross section and anisotropy of 2pσ molecular-orbital X-ray emission were calculated for 35- to 75-MeV Nb + Nb collisions.
Abstract: The cross section and anisotropy of 2pσ molecular-orbital X-ray emission is calculated for 35- to 75-MeV Nb + Nb collisions. The calculated intensities are a factor of 1.5 lower than the measured ones. The 2pσ molecular-orbital X-ray anisotropy is in good agreement with experiment. When one includes the Coriolis coupling between the 2pσ and 2pπ and between the 3dσ, 3dπ, and 3dδ molecular orbitals, the 2pσ-line-tail intensity is greatly reduced below that calculated by Jager et al., neglecting the Coriolis coupling. The implications of these calculations to the possible spectroscopy of superheavy quasi-molecules are discussed, and some suggestions are made to improve the accuracy of the spectroscopy measurements.
12 citations
TL;DR: In this paper, the Coulomb deflection correction factor for subshell vacancy-production cross sections was measured in equal-velocity (0.3-to 1.25 MeV/a.m.u.) proton and deuteron bombardments of Au, Pb, Th, and U targets.
Abstract: L -subshell vacancy-production cross sections were measured in equal-velocity (0.3- to 1.25 MeV/a.m.u.) proton and deuteron bombardments of Au, Pb, Th, and U targets, allowing a unique determination of the Coulomb deflection correction factor. Corrections to the measured cross sections for the energy loss of the projectile in ionizing the inner-shell electron are made. The measured Coulomb deflection factors are compared with various theories. Previously measured Coulomb deflection factors for K -vacancy production are re-evaluated, taking into account projectile-energy loss.
11 citations
TL;DR: In this paper, the self-association of imidazole and its hydrogen bonding to N, N-dimethylacetamide (DMA), tri-n-butyl phosphate (TBP) and tri n-octyl phosphine oxide (TOPO) in chloroform has been investigated by PMR method.
TL;DR: A new method for implementing frequency multiplication of square waves is presented, which is simpler and more flexible than any other method, and the accuracy of the output square wave can be improved easily by increasing the reference frequency.
Abstract: A new method for implementing frequency multiplication of square waves is presented. It is simpler and more flexible than any other method. The frequency multiplication parameter n can be programmable, therefore there is no need to change hardware when the parameter n is varied. In particular. the accuracy of the output square wave can be improved easily by increasing the reference frequency, in contrast with the conventional method which is subject to practical limitations, such as the linearity of the IC elements, especially the integrator.
TL;DR: In this paper, the local L 2 norm of the solution of the generalized Korteweg-de Vries equation has been shown to be the same as the local norm for the generalized k-means.
Abstract: We prove that the local L2 norm of the solution of the generalized Korteweg-de Vries equation
$$u_t + (F(u) + \sum\limits_{s = 0}^m {( - 1)^s D_x^{2s} u)_x = 0,m \geqslant 2,} $$
with nice initial datum, where F satisfies certain general conditions, for example, P(u) = up, where p is an odd integer ≧3, decays t o zero as time goes to infinity.
TL;DR: In this article, the distribution ratios of tet a tet b and cyclam in several solvent systems at 25°C as functions of hydrogen ion concentration were determined by spectrophotometric method.
Abstract: The distribution ratios of tet a tet b and cyclam in several solvent systems at 25°C as functions of hydrogen ion concentration were determined by spectrophotometric method. The protonation constants and the distribution constants or these macrocyclic ligands and their protonated species were obtained from the variations of the distribution ratios in the range of 5<-log[H+]<13.
TL;DR: In this article, a monoclinic space group P21/n compound was solved primarily by heavy atom method, and the final R value was 0.067, where R = 0.
Abstract: C18H19N2I, Mr=366.24, monoclinic, space group P21/n, a=6.298, b=7.659, c=32.579 A,β=101.54° (from Syntex Pl diffractometer), Z=4. Dc=1.59, Dx=1.58(2)gm cm−2 (by flotation), m. p. 253°C. The compound was solved primarily by heavy atom method. The final R value was 0.067.
TL;DR: In this article, a shell model calculation of the N = 51, 39 ≦ Z ≦ 42 nuclei is presented, where the 88 Sr nucleus is assumed to be an inert closed core and the extra-core protons are restricted to the 2 p 1 2, 1 g 9 2 and 1 g 7 2 configurations.
TL;DR: In this article, asymptotic expansions for the multivariate noncentral F distribution and for the distribution of latent roots in MANOVA and discriminant analysis are given for large error degrees of freedom.
TL;DR: In this article, the interactions of the ligand N, N -bis-(β-carbamoylethyl)-ethylenediamine (BCEN) with copper (II) in aqueous solution have been investigated by potentiometric and spectrophotometric techniques.
Abstract: The interactions of the ligand N, N -bis-(β-carbamoylethyl)-ethylenediamine (BCEN) with copper (II) in aqueous solution have been investigated by potentiometric and spectrophotometric techniques. The two protonation constants of the ligand at 25° in 0.2 M NaNO3are 105-51and 105-44 The quantitative equilibrium studies of the stepwise reactions which precede the formation of CuBCEN2+ and the Cu-O to Cu-N bond rearrangements at the two amide sites are described in detail. Electronic spectra of the copper (II) chelates formed are measured and discussed.
TL;DR: In this article, the Hartree-Fock-Roothaan method was used to obtain potential energy and dipole moment functions for the ground state of the water molecule, which were transformed and analyzed in terms of the normal symmetric stretching (v 1 ) and bending (v 2 ) coordinates for the calculation of i.r. transition matrix elements.
Abstract: Using the Hartree-Fock-Roothaan method, symmetric potential energy and dipole moment functions have been obtained for the ground state of the water molecule. These functions were transformed and analyzed in terms of the normal symmetric stretching ( v 1 ) and bending ( v 2 ) coordinates for the calculation of i.r. transition matrix elements. There is satisfactory agreement between this work and the experimental values for the transition matrix element of the v 2 fundamental. However, a discrepancy of a factor of 2.5 is observed between calculated and experimental matrix elements for the v 1 fundamental.
TL;DR: In this article, a smooth solution of utt − Δu + q(x) ¦ u ¦p−1u = 0 x ϵ R3, q ⩾ 0 and is C1, and 1 0, c > 1, and for simplicity, qr ⩽ 0.
TL;DR: In this article, the optimization of parameters controlling the fabrication of zinc electrodes, by the slurry paste method, has been carried out, and the optimum values obtained by a factorial experimental programme were: a zinc material that contains 2 −4 wt% HgO, 0·5 −2% PVA, and 94 −97·5% ZnO; a compression of 500 −1500 psi applied to the zinc electrode; and an electrode thickness of 0·265-0·35 mm.
Abstract: The optimization of parameters controlling the fabrication of zinc electrodes, by the slurry paste method, has been carried out. The parameters varied were active material composition, applied compression and electrode thickness. The optimum values obtained by a factorial experimental programme were: a zinc material that contains 2–4 wt% HgO, 0·5–2% PVA, and 94–97·5% ZnO; a compression of 500–1500 psi applied to the zinc electrode; and an electrode thickness of 0·265-0·35 mm.
01 Sep 1979
TL;DR: In this paper, the authors derived Lambert's formulas for the time of orbital flight between two points in space by first establishing a universal differential equation governing the time function, independent of the conic type of the trajectory, the focal characteristics of trajectory sector, and the range angle.
Abstract: Lambert's formulas for the time of orbital flight between two points in space are rederived by first establishing a universal differential equation governing the time function, independent of the conic type of the trajectory, the focal characteristics of the trajectory sector, and the range angle. A unified form of Lambert's formulas is then obtained as the general solution of the differential equation, and the various forms of the classical Lambert's formulas are obtained as its particular solutions under different boundary conditions. Following this basic treatment, various hypergeometric expansions for Lambert's time function and its derivatives are developed, and the behavior of the function and its implications in the solution of Lambert's problem and the isochronous trajectories are briefly reviewed. Finally, a short comparison of the present treatment with those found in current literature on Lambertian Mechanics is made and briefly discussed.
TL;DR: In this paper, a solid uranium amalgam containing as high as 1.7 g U/ml Hg was prepared electrolytically using a two-compartment electrolyzer separated with a cation exchange membrane at a kilogram scale.
Abstract: A solid uranium amalgam containing as high as 1.7 g U/ml Hg was prepared electrolytically using a two-compartment electrolyzer separated with a cation exchange membrane at a kilogram scale. The design and operation characteristics of the electrolyzer is described. The results indicate that ca. 170 g of uranium ion in an aqueous solution could be reduced to metallic state by forming amalgam within 4h with a current efficiency of 30% and uranium recovery of more than 80%
TL;DR: In this paper, all-valence-electron IEHT and CNDO/2 molecular orbital calculations and an infrared vibrational normal coordinate analysis were carried out for the study of the bonding in the title compound with its six-membered ring, repeating, all-four-coordinated NBC sequence.
TL;DR: In this paper, the average concentrations of the trace elements of air particulates were made among industrial, heavy-traffic and residential areas, and the pollution level of Hong Kong with other cities was also made.
Abstract: Nondestructive neutron activation analysis employing reactor neutrons and a Ge(Li) gamma-spectrometer has been used to determine the trace element level of air particulates in various areas of Hong Kong. Comparison of the average concentrations of the trace elements of air particulates was made among industrial, heavy-traffic and residential areas. It was found that industrial areas have higher concentrations of Co, Cr, Hg, Mn and Zn, while heavy-traffic areas have very high concentrations of Br. Comparison of the pollution level of Hong Kong with other cities was also made. The average concentrations of Co, Cr, Hg, Zn and Br of air particulates in Hong Kong were found to have higher values than those of other cities. Finally, daily variation of the trace element level in a special area (Hung Hom) had been studied, but no significant variation was found.
TL;DR: In this article, the authors provide a rigorous incremental finite element procedure using both the conventional and hybrid displacement model to analyze in-service situations of two-dimensional eleastic-plastic fracture mechanics problems under large-scale yielding with arbitrary strain hardening material behaviors.
Abstract: This paper provides a rigorous incremental finite element procedure using both the conventional and hybrid‐displacement model to analyze in‐service situations of two‐dimensional eleastic‐plastic fracture mechanics problems under large‐scale yielding with arbitrary strain hardening material behaviors. To account for both the geometric nonlinearity and material nonlinearity, a tangent modulus incremental numerical method is employed. The fracture center‐cracked test specimen made of Ni‐Cr‐Mo—V rotor steel is solved. An acceptable JIC ductile fracture initiation criterion with finite deformation assumptions is constructed. Excellent correlations between the directly computed results and available experimental data are noted.
TL;DR: In this article, the ion damaged effect and subsequent isothermal annealing in boron-implanted Si was studied by positron annihilation lifetime measurements, and the mean positron lifetime in preimplanted n-type Si is 243 psec.