RESUMEN
The phase-mismatch effect due to polarization-dependent mode confinement factor has been shown to be not a crucial problem in semiconductor optical amplifiers (SOAs) and is usually not accounted for. The phase-mismatch four-wave mixing (FWM) process in SOA devices is experimentally reported. The results reveal a sinc-like behavior in the intensity of FWM conjugate as a function of wavelength separation between transverse electric (TE)/transverse magnetic (TM) pumps due to induced confinement factors difference. Efficient FWM occurred for a detuning shift of about 500 GHz, limited by phase-mismatch conditions and determined by coherence length required for low and high frequencies to complete a full phase-match cycle. Phase-match FWM with an infinity coherence length can be fulfilled by proper alignments of co-polarized TE/TM modes of input waves with respect to the birefringent axes of the device structure.
RESUMEN
Hydrocarbon resins are used to modify polymer products to achieve desired functional properties for a diverse range of products. These complex hydrocarbon-based mixtures are typically poorly soluble in water. However, resins may leach lower-molecular-weight monomers or impurities upon contact with water, thus posing a potential hazard to the aquatic environment. The bioavailability and toxicity of leachable constituents of four solid and three liquid resins were evaluated by analyzing water-accommodated fractions prepared with each resin, using biomimetic solid phase microextraction (SPME) techniques. Liquid resins exhibited concentrations of bioavailable constituents that were sufficiently elevated to cause acute toxicity to the aquatic organism Daphnia magna. All solid resins exhibited lower bioavailable concentrations of leachable constituents that were unlikely to pose an aquatic toxicity concern. Since observed toxicity of both resin types was generally consistent with bioavailable concentrations determined using SPME fiber measurements, it is concluded that this approach provides a convenient in vitro screening tool that can help reduce the use of animal testing in environmental hazard assessment of complex hydrocarbon-based substances.
Asunto(s)
Alternativas a las Pruebas en Animales , Resinas Sintéticas/toxicidad , Pruebas de Toxicidad/métodos , Contaminantes Químicos del Agua/toxicidad , Animales , Disponibilidad Biológica , Materiales Biomiméticos , Daphnia , Dimetilpolisiloxanos , Femenino , Hidrocarburos/toxicidad , Reproducción/efectos de los fármacos , Dióxido de Silicio , SiliconasRESUMEN
An all-optical AND gate based on optically induced nonlinear polarization rotation of a probe light in a bulk semiconductor optical amplifier is realized at a bit rate of 2.5Gbit/s. By operating the AND gate in an up and inverted wavelength conversion scheme, the extinction ratio is improved by 8dB compared with previously published work.
Asunto(s)
Hospitales Urbanos/economía , Servicio de Mantenimiento e Ingeniería en Hospital/organización & administración , Eliminación de Residuos Sanitarios/métodos , Conservación de los Recursos Naturales/economía , Ahorro de Costo/métodos , Equipo Reutilizado/economía , Administradores de Hospital , Eliminación de Residuos Sanitarios/economía , Ciudad de Nueva YorkRESUMEN
Nurses in this ambulatory care center recognized a need for a systematic, planned approach to health education, and developed a health education model. The nurses on the committee serve as inhouse consultants to help other nurses develop, implement, and evaluate health education programs.