996 resultados para Spectrofluorimetry, Nitrofurans, Kinetics, way, Nonlinear, Chemometrics


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Una historia sobre el acoso en la escuela que cuenta con dos personajes principales; una niña y un muchacho que es un matón La escuela es multi-cultural, pero los personajes principales no lo son. Jane tiene un gato llamado Furlong que la acompaña a la escuela todos los días, y luego vuelve a casa por su propio camino. Ella es feliz en la escuela hasta que William, el nuevo alumno, comienza a intimidarla, entonces decide volver a casa por el mismo camino que su gato Furlong. Para lectura en grupo.

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Una historia sobre el acoso en la escuela que cuenta con dos personajes principales; una niña y un muchacho que es un matón La escuela es multi-cultural, pero los personajes principales no lo son. Jane tiene un gato llamado Furlong que la acompaña a la escuela todos los días, y luego vuelve a casa por su propio camino. Ella es feliz en la escuela hasta que William, el nuevo alumno, comienza a intimidarla, entonces decide volver a casa por el mismo camino que su gato Furlong. Para lectura en grupo.

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Caja con cien tarjetas de conceptos clave y más de trescientas preguntas y respuestas. Cada tarjeta se centra en un tema o concepto, con hasta cuatro preguntas breves en un lado y las respuestas en el reverso, junto con una nota del examinador.

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Guía de apoyo para alumnos de educación secundaria de segundo ciclo que sigan la especificación de AQA (Assessment and Qualifications Alliance) en el nivel A2 del área de química. Está dividida en tres secciones: una introducción con consejos y técnicas para la realización del examen; una guía de contenido con los principales conceptos y temas (cinética, equilibrio, ácidos y bases, nomenclatura e isomería en química orgánica, compuestos del grupo carbonilo, química aromática, aminas, aminoácidos, polímeros, análisis y síntesis orgánica y determinación de estructura); y una sección con preguntas de examen y respuestas comentadas por un examinador.

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CD audio con ejercicios de vocabulario en inglés para el nivel intermedio bajo o intermedio. Contiene veintitrés lecciones con una duración total aproximada de veintinueve minutos. Su objetivo es permitir a los profesores enseñar vocabulario de una forma más comunicativa y permitir a los alumnos desarrollar habilidades de aprendizaje que les ayudarán a ser más eficaces al organizar, almacenar y recordar el vocabulario nuevo.

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Resumen tomado de la publicación

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Resumen basado en el de la publicaci??n

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Three conjugated organic molecules that span a range of polarity and valence-bond/charge transfer characteristics were studied. It was found that dispersion can be insignificant, and that adequate treatment can be achieved with frequency-dependent field-induced vibrational coordinates (FD-FICs)

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Electrical property derivative expressions are presented for the nuclear relaxation contribution to static and dynamic (infinite frequency approximation) nonlinear optical properties. For CF4 and SF6, as opposed to HF and CH4, a term that is quadratic in the vibrational anharmonicity (and not previously evaluated for any molecule) makes an important contribution to the static second vibrational hyperpolarizability of CF4 and SF6. A comparison between calculated and experimental values for the difference between the (anisotropic) Kerr effect and electric field induced second-harmonic generation shows that, at the Hartree-Fock level, the nuclear relaxation/infinite frequency approximation gives the correct trend (in the series CH4, CF4, SF6) but is of the order of 50% too small

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A general reduced dimensionality finite field nuclear relaxation method for calculating vibrational nonlinear optical properties of molecules with large contributions due to anharmonic motions is introduced. In an initial application to the umbrella (inversion) motion of NH3 it is found that difficulties associated with a conventional single well treatment are overcome and that the particular definition of the inversion coordinate is not important. Future applications are described

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The vibrational configuration interaction method used to obtain static vibrational (hyper)polarizabilities is extended to dynamic nonlinear optical properties in the infinite optical frequency approximation. Illustrative calculations are carried out on H2 O and N H3. The former molecule is weakly anharmonic while the latter contains a strongly anharmonic umbrella mode. The effect on vibrational (hyper)polarizabilities due to various truncations of the potential energy and property surfaces involved in the calculation are examined

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A variational approach for reliably calculating vibrational linear and nonlinear optical properties of molecules with large electrical and/or mechanical anharmonicity is introduced. This approach utilizes a self-consistent solution of the vibrational Schrödinger equation for the complete field-dependent potential-energy surface and, then, adds higher-level vibrational correlation corrections as desired. An initial application is made to static properties for three molecules of widely varying anharmonicity using the lowest-level vibrational correlation treatment (i.e., vibrational Møller-Plesset perturbation theory). Our results indicate when the conventional Bishop-Kirtman perturbation method can be expected to break down and when high-level vibrational correlation methods are likely to be required. Future improvements and extensions are discussed

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The level of ab initio theory which is necessary to compute reliable values for the static and dynamic (hyper)polarizabilities of three medium size π-conjugated organic nonlinear optical (NLO) molecules is investigated. With the employment of field-induced coordinates in combination with a finite field procedure, the calculations were made possible. It is stated that to obtain reasonable values for the various individual contributions to the (hyper)polarizability, it is necessary to include electron correlation. Based on the results, the convergence of the usual perturbation treatment for vibrational anharmonicity was examined

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Initial convergence of the perturbation series expansion for vibrational nonlinear optical (NLO) properties was analyzed. The zero-point vibrational average (ZPVA) was obtained through first-order in mechanical plus electrical anharmonicity. Results indicated that higher-order terms in electrical and mechanical anharmonicity can make substantial contributions to the pure vibrational polarizibility of typical NLO molecules