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1.
Nano Lett ; 22(21): 8541-8549, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36287197

RESUMO

Addressable quantum states well isolated from the environment are of considerable interest for quantum information science and technology. Carbon nanotubes are an appealing system, since a perfect crystal can be grown without any missing atoms and its cylindrical structure prevents ill-defined atomic arrangement at the surface. Here, we develop a reliable process to fabricate compact multielectrode circuits that can sustain the harsh conditions of the nanotube growth. Nanotubes are suspended over multiple gate electrodes, which are themselves structured over narrow dielectric ridges to reduce the effect of the charge fluctuators of the substrate. We measure high-quality double- and triple-quantum dot charge stability diagrams. Transport measurements through the triple-quantum dot indicate long-range tunneling of single electrons between the left and right quantum dots. This work paves the way to the realization of a new generation of condensed-matter devices in an ultraclean environment, including spin qubits, mechanical qubits, and quantum simulators.

2.
Phys Rev Lett ; 108(12): 120801, 2012 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-22540567

RESUMO

A cavity optomechanical magnetometer is demonstrated. The magnetic-field-induced expansion of a magnetostrictive material is resonantly transduced onto the physical structure of a highly compliant optical microresonator and read out optically with ultrahigh sensitivity. A peak magnetic field sensitivity of 400 nT Hz(-1/2) is achieved, with theoretical modeling predicting the possibility of sensitivities below 1 pT Hz(-1/2). This chip-based magnetometer combines high sensitivity and large dynamic range with small size and room temperature operation.


Assuntos
Magnetometria/instrumentação , Óptica e Fotônica/instrumentação , Modelos Teóricos
3.
Arch Gynecol Obstet ; 283(3): 469-74, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20174814

RESUMO

OBJECTIVE: The purpose of this retrospective study was to find a method of improving the accuracy of fetal birth weight estimation on the basis of traditional ultrasonographic measurements of the head, thorax, and femur at term. In this context, we analyzed a novel regression method comparing to existing algorithms. METHODS: The delivery records of two hospitals were searched for women who delivered macrosomic infants, and the patients' medical records were retrospectively reviewed in order to derive clinical and ultrasonographic data at term. A total of 223 patients with macrosomic infants (birth weight > 4,000 g) were identified. These patients were complemented by data for 212 women who had ultrasound fetal assessments of less than 4,000 g. We used the method of isotonic regression to construct a birth weight prediction function that increases monotonically with each of the input variables and which minimizes the empirical quadratic loss. RESULTS: A suspicion of macrosomia was based on a history of macrosomia, fundal height, and sonographic weight estimation >4,000 g. The mean period between ultrasound weight estimation and delivery was 7.2 days. The ability of the biometric algorithms developed to predict fetal weight at term ranged between a mean absolute error of 312 and 344 g, given a confidence interval of 95%. We demonstrate that predictions of birth weight on the basis of ultrasound data can be improved significantly, if an isotonic regression model is used instead of a linear regression model. CONCLUSIONS: This study demonstrates that ultrasound detection of macrosomia can be improved using the isotonic regression method.


Assuntos
Algoritmos , Macrossomia Fetal/diagnóstico por imagem , Peso Fetal , Adolescente , Adulto , Peso ao Nascer , Feminino , Humanos , Gravidez , Estudos Retrospectivos , Ultrassonografia Pré-Natal , Adulto Jovem
4.
Water Res ; 44(12): 3725-33, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20546837

RESUMO

A Water Framework Directive pilot project combines measured data and model approaches to calculate fluxes and mass balance of the pesticide bentazone in an 81 km section of the river Main (Germany). During the study period (six weeks in spring 2004) the observed bentazone inflow and outflow in the river section amounted to 52.8 and 53.1 kg, respectively; the maximum concentrations reached 220 and 290 ng l(-1). Based on sampling of seven sewage treatment plants a specific loss of 0.87 g bentazone per farm was calculated. Extrapolation to the entire sub-basin results in 2.6 kg bentazone in total as point source contribution from farms. Diffuse input into the surface water network occurred after an intensive rainfall event on May 7th. Total bentazone load was simulated with the pesticide emission model DRIPS to be 23.2 kg. One third of this load was estimated to be degraded by photolysis before reaching the main waterway, the river Main. The ATV water quality model was applied to predict the concentration profile of bentazone in river Main between Schweinfurt and Würzburg with reasonable results. The difference between total measured and modeled fluxes amounted to 1.5 kg corresponding to 2% of the overall input. The combined approach of monitoring and modeling appears to be a valuable strategy to quantify the relevance of point and non-point sources and to focus effective mitigation measures to the most relevant origins within a river basin.


Assuntos
Benzotiadiazinas/isolamento & purificação , Modelos Químicos , Rios/química , Benzotiadiazinas/química , Simulação por Computador , Geografia , Alemanha , Laboratórios , Praguicidas/isolamento & purificação , Projetos Piloto , Esgotos/química , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água
5.
Nahrung ; 35(10): 1013-21, 1991.
Artigo em Alemão | MEDLINE | ID: mdl-1800904

RESUMO

A flavour profile analysis has been developed for the evaluation of carbon dioxide extracts of marjoram. On the basis of the commercial quality of various proveniences of marjoram a first flavour profile was established. Components which decisively influence the flavour were examined for the determination of relevance factors. The taste profile is the basis for the calculation of the quality coefficient as measure of the sensory quality. The expert profile as a theoretical model is based on optimum intensities of individual taste components. Differences from the expert profile are considered by corrected intensities and lead to a decrease of the quality coefficient. The method used for the development of a high pressure extraction technology is quite suitable for the characterization of marjoram extracts as well as for the evaluation of commercial marjoram samples.


Assuntos
Condimentos/análise , Paladar , Dióxido de Carbono , Humanos , Modelos Biológicos , Pressão
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