988 resultados para dilute Temperley-Lieb algebra


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Freezing point depressions (¿Tf) of dilute solutions of several alkali metal chlorides and bromides were calculated by means of the best activity coefficient equations. In the calculations, Hückel, Hamer and Pitzer equationswere used for activity coefficients. The experimental ¿Tf values available in the literature for dilute LiCl, NaCl and KBr solutions can be predicted within experimental error by the Hückel equations used. The experimental ¿Tf values for dilute LiCl and KBr solutions can also be accurately calculated by corresponding Pitzer equations and those for dilute NaCl solutions by the Hamer equation for this salt. Neither Hamer nor Pitzer equations predict accurately the freezing points reported in the literature for LiBr and NaBr solutions. The ¿Tf values available for dilute solutions of RbCl, CsCl or CsBr are not known at the moment accurately because the existing data for these solutions are not precise. The freezing point depressions are tabulated in the present study for LiCl, NaCl and KBr solutions at several rounded molalities. The ¿Tf values in this table can be highly recommended. The activity coefficient equations used in the calculation of these values have been tested with almost allhigh-precision electrochemical data measured at 298.15 K.

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In this paper we propose an approach to homotopical algebra where the basic ingredient is a category with two classes of distinguished morphisms: strong and weak equivalences. These data determine the cofibrant objects by an extension property analogous to the classical lifting property of projective modules. We define a Cartan-Eilenberg category as a category with strong and weak equivalences such that there is an equivalence of categories between its localisation with respect to weak equivalences and the relative localisation of the subcategory of cofibrant objects with respect to strong equivalences. This equivalence of categories allows us to extend the classical theory of derived additive functors to this non additive setting. The main examples include Quillen model categories and categories of functors defined on a category endowed with a cotriple (comonad) and taking values on a category of complexes of an abelian category. In the latter case there are examples in which the class of strong equivalences is not determined by a homotopy relation. Among other applications of our theory, we establish a very general acyclic models theorem.

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This Master's thesis is devoted to semiconductor samples study using time-resolved photoluminescence. This method allows investigating recombination in semiconductor samples in order to develop quality of optoelectronic device. An additional goal was the method accommodation for low-energy-gap materials. The first chapter gives a brief intercourse into the basis of semiconductor physics. The key features of the investigated structures are noted. The usage area of the results covers saturable semiconductor absorber mirrors, disk lasers and vertical-external-cavity surface-emittinglasers. The experiment set-up is described in the second chapter. It is based on up-conversion procedure using a nonlinear crystal and involving the photoluminescent emission and the gate pulses. The limitation of the method was estimated. The first series of studied samples were grown at various temperatures and they suffered rapid thermal annealing. Further, a latticematched and metamorphically grown samples were compared. Time-resolved photoluminescence method was adapted for wavelengths up to 1.5 µm. The results allowed to specify the optimal substrate temperature for MBE process. It was found that the lattice-matched sample and the metamorphically grown sample had similar characteristics.

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The theory of electrolyte solutions was described by explaining Debye–Hückel theory and deriving the Debye–Hückel equation for the mean activity coefficient. Simple two-parameter Hückel equation was used for the calculation of the activity coefficients of aqueous hydrobromic and hydriodic acids up to 0.5 mol/kg at temperatures from (0 to 60) °C and from (0 to 50) °C, respectively. The parameters were observed to be independent of the temperature. The Hückel equation for the osmotic coefficients of water in the studied solutions was compared to that of Pitzer model by predicting the vapor pressures up to 1 mol/kg at 25 °C. The experimental vapor pressures over the reference electrolyte solutions were calculated with the Pitzer equation for the osmotic coefficients for isopiestic data in this comparison. The simple Hückel model was found to be equally good as the Pitzer model for both hydrobromic and hydriodic acids up to 0.5 mol/kg at 25 °C but applies also to other temperatures studied.

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Konserttitaltiointi Sommerliche Musiktage Hitzacker -festivaaleilta 1973.

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Traduction Chinoise par Alexander Wylie (1815-1887), rédigée par Li Shan lan, de Hai ning. Préface Chinoise par Wylie (1859) ; préface anglaise, écrite par le même à Shang hai (octobre 1859), contenant un historique des mathématiques en Chine. Imprimé en caractères mobiles, dans la maison Mo hai (1859).Livre préliminaire + 13 livres.

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This thesis reports on the optical properties of the dilute magnetic semiconductors, Sb1.97 V 0.03 Te3 and Sb1.94Cr0.06Te3, along with the parent compound Sb2Te3' These materials develop a ferromagnetic state at low temperature with Curie temperatures of 22 K and 16 K respectively. All three samples were oriented such that the electric field vector of the light was perpendicular to the c-axis. The reflectance profile of these samples in the mid-infrared (500 to 3000 cm-1) shows a pronounced plasma edge which retracts with decreasing temperature. The far-infrared region of these samples exhibits a phonon at ~ 60 cm-1 which softens as temperature decreases. Kramers-Kronig analysis and a Drude-Lorentz model were employed to determine the optical constants of the bulk samples. The real part of the optical conductivity is shown to consist of intraband contributions at frequencies below the energy gap (~0.26 eV) and interband contributions at frequencies above the energy gap. The temperature dependence of the scattering rate show that a mix of phonon and impurity scattering are present, while the signature of traditional spin disorder (magnetic) scattering was difficult to confirm.

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Tesis (Maestría en Ingenieria Industrial con Especialidad en Sistemas) UANL

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UANL

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UANL

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UANL

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UANL