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941.
Joseph S. Alper Robert I. Gelb Marietta H. Schwartz 《Journal of inclusion phenomena and macrocyclic chemistry》1991,11(4):349-360
In a previous paper [1] the complexation behavior of 1,4,8,12-tetraazacyclopentadecane with various anions was studied. This analysis depended on various assumptions involving the accuracy and the interpretation of the experimental data. In this paper these assumptions are examined using pH potentiometry,13C NMR, and conductometric techniques. The validity of each of the assumptions was confirmed. 相似文献
942.
Joseph R. Lakowicz Ignacy Gryczynski Józef Kuśba Eva Danielsen 《Journal of fluorescence》1992,2(4):247-258
We measured the fluorescence intensity and anisotropy decays of 1,6-diphenyl-1,3,5-hexatriene (DPH)-labeled membranes resulting from simultaneous two-photon excitation of fluorescence. Comparison of these two-photon data with the more usual one-photon measurements revealed that DPH displayed identical intensity decays, anisotropy decays, and order parameters for one- and two-photon excitation. While the anisotropy data are numerically distinct, they can be compared by use of the factor 10/7, which accounts for the two-photon versus one-photon photoselection. The increased time 0 anisotropy of DPH can result in increased resolution of complex anisotropy decays. Global analysis of the one- and two-photon data reveals consistency with a single apparent angle between the absorption and the emission oscillators. The global anisotropy analysis also suggests that, except for the photoselection factor, the anisotropy decays are the same for one-and two-photon excitation. This ideal behavior of DPH as a two-photon absorber, and its high two-photon cross section, makes DPH a potential probe for confocal two-photon microscopy and other systems where it is advantageous to use long-wavelength (680- to 760-nm) excitation. 相似文献
943.
This paper is a review of the present status of studies relating to occurrence of deterministic chaos and its characterization
in one-dimensional maps. As our primary aim is to introduce the nonspecialists into this fascinating world of chaos we start
from very elementary concepts and give sufficient arguments for clarity of ideas. The two main scenarios during onset of chaos
viz. the period doubling and intermittency are dealt with in detail. Although the logistic map is often discussed by way of
illustration, a few more interesting maps are mentioned towards the end. 相似文献
944.
David F. Bliss Robert M. Hilton Stephen Bachowski Joseph A. Adamski 《Journal of Electronic Materials》1991,20(12):967-971
We have used a combined magnetic liquid encapsulated Kyropoulos/Czochralski (MLEK/ MLEC) technique to produce twin-free indium
phosphide (InP) crystals. This technique has advantages over the standard LEC method used for commercial production of InP.
By stabilizing convective flows with a magnetic field and controlling the angle between solid and liquid, one can grow large
diameter twin-free (100) InP crystals; they are shaped with a flat top as is typical for Kyropoulos growth, and then pulled
from the magnetically stabilized melt as in Czochralski growth. This shaping method has the benefit of maximizing the number
of single crystal wafers which can be sliced from the boule. MLEK InP growth is distinguished from other methods such as LEC
and MLEC with respect to solid-liquid interface shape, dislocation density, and impurity distribution. This process has demonstrated
that twin-free InP (100) crystals can be consistently grown. 相似文献
945.
946.
Ralph E. Schlief Wlodzimierz Jarzeba Khalid A. M. Thakur Joseph C. Alfano Alan E. Johnson Paul F. Barbara 《Journal of Molecular Liquids》1994,60(1-3):201-220
Ultrafast pump - probe measurements have been made on the benzene - bromine atom charge transfer (CT) complex in CCl4 and cyclohexane solutions. Ultrafast optical excitation of the CT band of the complex yields an ion pair, which is comprised of a benzene cation and a bromide anion. The rate of charge recombination between the bromide and the benzene cation in the ion pair has been observed to be much faster than the rate of diffusion apart. The charge recombination rate is accelerated at high benzene concentrations as a result of the formation of a benzene dimer cation - bromide ion pair which undergoes much faster charge recombination than the benzene cation - bromide ion pair. 相似文献
947.
In this paper we consider scalar convex conservation laws in one space variable in a stripD =(x, t): 0 ≤x ≤1,t > 0 and obtain an explicit formula for the solution of the mixed initial boundary value problem, the boundary data being
prescribed in the sense of Bardos-Leroux and Nedelec. We also get an explicit formula for the solution of weighted Burgers
equation in a strip. 相似文献
948.
Joseph A. Scalise 《Microelectronics Reliability》1998,38(3):353
Microcircuit package qualification testing is used to establish the reliability of integrated circuit processes and devices as they relate to part packaging. This paper presents the results of package qualification tests conducted on plastic encapsulated microcircuits (PEMs) and plastic discrete devices (diodes, transistors) used in avionics applications. Highly accelerated stress test (HAST) and temperature cycle (TC) test results, including part failure mechanisms and associated failure rates, are provided. A variety of plastic package styles and integrated circuit functions have been tested. Examples of package styles tested include small outline (SO), plastic leaded chip carrier (PLCC), thin small outline package (TSOP), plastic quad flat package (PQFP) and plastic dual-in-line (PDIP).Manufacturers' devices have been evaluated and various plastic compounds have been compared to determine which provide optimum reliability. The testing showed that package qualification performance of PEMs is affected by type of compound, passivation (including die coat) and die size. HAST failures are caused by moisture penetration of the package while temperature cycle failures result from coefficient of thermal expansion (CTE) mismatch effects. 相似文献
949.
950.
Primal–dual interior point methods and the HKM method in particular have been implemented in a number of software packages
for semidefinite programming. These methods have performed well in practice on small to medium sized SDPs. However, primal–dual
codes have had some trouble in solving larger problems because of the storage requirements and required computational effort.
In this paper we describe a parallel implementation of the primal–dual method on a shared memory system. Computational results
are presented, including the solution of some large scale problems with over 50,000 constraints. 相似文献