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951.
The set of solutions for Boolean equations are required in certain classes of bivalent programming and deterministic scheduling problems. The purpose here is to determine the set of solutions in a general manner. The aim is not directed toward an optimal solution. General truth table concepts are reviewed and extended.The extensions are threefold: (a) a reinterpretation of the truth table concepts for the designation numbers that identify the vertices of the unit hypercube, (b) a statement of a primitive algorithm for the computation of the set of designation numbers which correspond to the vertices of the solution space and (c) an extension of this primitive algorithm.  相似文献   
952.
Protolytic equilibria often have profound effects on chemical activity, since protolytic species usually behave quite differently. It is therefore important to characterize the protolytic properties of important chemicals. Here we present a new approach to study protolytic equilibria of fluorescent species that is extremely accurate and relies on minimum assumptions. We show that by measuring 2-dimensional excitation/emission scans of samples at different pH. the 3-dimensional experimental data set, I(lambda(ex), lambda(em), C(pH)), can be unambiguously decomposed into the spectral responses of the protolytic species present as well as their concentration. The approach is demonstrated on the protolytic equilibrium of fluorescein. Although the fluorescein monoanion cannot be obtained in pure form, the spectra and concentrations of both fluorescein species, as well as the protolytic constant, are determined with excellent accuracy. The proposed method is general and can be applied not only for studies of protolytic equilibria, but on any chemical equilibria and chemical reactions involving fluorescent species.  相似文献   
953.
The total mass attenuation coefficients for Co, Cu, Ni elements and CoCu, CoCuNi alloys were measured at different energies with 11.88, 13.93, 17.59, 21.09 and emitted an point source using transmission arrangement. The gamma rays were counted by a Si(Li) detector with a resolution of at . Also the mass attenuation coefficients of each alloy (CoCu, CoCuNi) were estimated using mixture rule. The measured values were compared with estimated values for alloys.  相似文献   
954.
Effects of ultrasonic energy on the wash fastness of reactive dyes   总被引:10,自引:0,他引:10  
Akalin M  Merdan N  Kocak D  Usta I 《Ultrasonics》2004,42(1-9):161-164
The field of ultrasonic is still making strides towards perfection, but already many applications of ultrasonic energy have been found in science and technology. There is also a field called sonochemistry where ultrasonic energy is used to create some chemical and mechanical effects on matter immersed or solved in liquids. It was presumed that ultrasonic textile washing could be a competitive alternative to conventional textile washing techniques; and as such the following experiments were conducted. In this study, the effects of ultrasonic energy on the wash fastness of reactive dyes, which have three different reactive groups, were investigated. After dyeing with the conventional method, the samples were applied with three types of washing processes simultaneously (conventional, ultrasonic probe and ultrasonic bath) and comparisons were made. Three different fixing agents were used in the washing processes. Colourfastness, staining fastness, magnitude of total colour difference (DeltaE) and lightness difference of the colour (DeltaL) values of dyed samples were measured.  相似文献   
955.
The synthesis of gamma-functionalized cyclopentenones was carried out in a few steps, starting firstly with the preparation of nitroketonic intermediates 2, which were readily transformed into 1,4-diketones using the Nef conversion. The intramolecular cyclization of the gamma-diketones 3 in a basic medium, led to the functionalized cyclopentenones 4.  相似文献   
956.
Ar2(+) ions produced in a cooled supersonic expansion by electron-impact ionization are accelerated at 2.5 keV and kept during few milliseconds inside a linear electrostatic trap. The lifetime of the metastable Ar2(+) ion is determined from the measurement of the rate of the argon atoms escaping the trap. The lifetime and the relative metastable populations are measured as a function of the pressure and temperature in the supersonic expansion, i.e., of the mean cluster size. Possible mechanisms responsible for the metastable formation are discussed.  相似文献   
957.
958.
The intersubband optical absorption in an asymmetric double quantum well for different barrier widths and the right well widths are theoretically calculated within the framework of effective mass approximation. The results obtained show that the intersubband transitions and the energy levels in an asymmetric double quantum well can be importantly modified and controlled by the barrier width and the well width. The sensitivity to the barrier and well widths of the absorption coefficient can be used in various optical semiconductor device applications.  相似文献   
959.
A space X is called C-closed if every countably compact subset of X is closed in X. We study the properties of C-closed spaces. Among other results, it is shown that countably compact C-closed spaces have countable tightness and under Martin's Axiom or 2ω0<2ω1, C-closed is equivalent to sequential for compact Hausdorff spaces. Furthermore, every hereditarily quasi-k Hausdorff space is Fréchet-Urysohn, which generalizes a theorem of Arhangel'sk in [4]. Also every hereditarily q-space is hereditarily of pointwise countable type and contains an open dense first countable subspace.  相似文献   
960.
The concentration of 18 elements in different cane sugar products, i.e., cane sugar plants, crude and syrup juices, molasses, and the end products of the consumer sugar, were analyzed and processed. The samples were collected from five citics, i.e., Kom Ombo, Edfu, Armant, Deshna and Naga Hammady in Upper Egypt where the main Egyptian sugar industry factories are located. INAA was applied for the determination of Al, Ca, Cl, Co, Cr, Fe, Mg, Mn, Na and Sc, while Cu, Li, P, Sn, V and Zn were determined by ICP-AES and Pb and As were determined by AAS. These three analytical methods were applied to optimize the sensitivity and the accuracy of the measurements in order to provide a sound basis for the obtention of reliable clustering results.  相似文献   
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