10,000 publications from this institution
Carrier distribution and dynamics in semiconductor materials often govern their physical properties that are critical to functionalities and performance in industrial applications. The continued miniaturization of electronic and photonic devices calls for tools to probe carrier behavior in semiconductors simultaneously at the picosecond time and nanometer length scales. Here, we report pump-probe optical nanoscopy in the visible-near-infrared spectral region to characterize the carrier dynamics in silicon nanostructures. By coupling experiments with the point-dipole model, we resolve the size-dependent photoexcited carrier lifetime in individual silicon nanowires. We further demonstrate local carrier decay time mapping in silicon nanostructures with a sub-50 nm spatial resolution. Our study enables the nanoimaging of ultrafast carrier kinetics, which will find promising applications in the future design of a broad range of electronic, photonic, and optoelectronic devices.
En Castigar a los pobres, mostré que el ascenso del Estado Penal en los Estados Unidos y otras sociedades avanzadas en el último cuarto de siglo es una respuesta a la creciente inseguridad social y no a la inseguridad criminal, que los cambios en la asistencia social y las políticas judiciales están vinculados entre sí, el tan restrictivo workfare y el tan expansivo prisonfare se unen en un artefacto único de organización para la disciplina de las fracciones precarizadas de la clase trabajadora en la era post-industrial, y que un sistema carcelario diligente no es una desviación, sino un elemento constitutivo del Leviatán neoliberal. En este artículo, extraigo las consecuencias teóricas de ese diagnóstico respecto al gobierno emergente de la inseguridad social. Utilizo el concepto de campo burocrático de Bourdieu para revisar la tesis clásica de Piven y Cloward sobre la regulación de la pobreza a través de la asistencia público, y contrastar el modelo de penalización como técnica para la gestión de la marginalidad urbana con la visión de Michel Foucault sobre la sociedad disciplinaria, las consideraciones de David Garlad sobre la cultura del control y la caracterización de David Harvey acerca de la política neoliberal. Contra la concepción estrecha del neoliberalismo como una regla del mercado, se propone una especificación de mayor densidad sociológica que implica prestaciones sociales de supervisión, un estado penal proactivo y el tropo cultural de la responsabilidad individual. Esto sugiere que es necesario teorizar, no respecto a la prisión como una técnica práctica para aplicar la ley, sino como un núcleo cuya capacidad política selectiva y agresiva descargada sobre las regiones inferiores del espacio social viola los ideales de la ciudadanía democrática.<br>In Punishing the Poor, I show that the ascent of the penal state in the United States and other advanced societies over the past quarter-century is a response to rising social insecurity, not criminal insecurity; that changes in welfare and justice policies are interlinked, as restrictive ''workfare'' and expansive ''prisonfare'' are coupled into a single organizational contraption to discipline the precarious fractions of the postindustrial working class; and that a diligent carceral system is not a deviation from, but a constituent component of, the neoliberal Leviathan. In this article, I draw out the theoretical implications of this diagnosis of the emerging government of social insecurity. I deploy Bourdieu's concept of ''bureaucratic field'' to revise Piven and Cloward's classic thesis on the regulation of poverty via public assistance, and contrast the model of penalization as technique for the management of urban marginality to Michel Foucault's vision of the ''disciplinary society,'' David Garland's account of the ''culture of control,'' and David Harvey's characterization of neoliberal politics. Against the thin economic conception of neoliberalism as market rule, I propose a thick sociological specification entailing supervisory workfare, a proactive penal state, and the cultural trope of ''individual responsibility.'' This suggests that we must theorize the prison not as a technical implement for law enforcement, but as a core political capacity whose selective and aggressive deployment in the lower regions of social space violates the ideals of democratic citizenship.
A model based on the movement of point defects in an electrostatic field is proposed to interpret the growth behavior of a passive film on a metal surface. This model results in a logarithmic growth law. The theoretical equations derived from the model readily account for experimental data for the growth of a passive film on iron. It is found that the field strength of the film is . The dependence of film/solution interface potential difference on the applied potential (α) was found to be 0.743, and is independent of the identity of the anion in solution. However, the dependence of the potential difference across the film/solution interface on the solutionpH (β) is strongly dependent on the identity of the solution anion.
We introduce a model for joint texture classification and segmentation that learns not only how to classify accurately, but when to classify efficiently. This model, combined with a complementary efficient feature representation that we describe, allows us to move beyond naive slidingwindow classification strategies into sub-linear coarse-tofine classification of an entire image. Recognition is formulated as a scale-space traversal through the image in which we can “stop short ” at coarse scales, dramatically increasing both the speed and the accuracy of classification. Unlike other models, ours is constructed such that the classification produced when stopping-short is exact (that is, equivalent to the classification produced when not stopping-short), because coarse-to-fine efficiency is directly incorporated into the model. Classification is demonstrated on partially- and fully-annotated datasets of satellite and medical imagery. for accurate classification that is, on average, of sub-linear complexity relative to the size of the image. A quad-tree[5] is used as a medium for multiresolution inference, and we features inspired by the integral image technique in [1] for efficient feature generation. The output of this system is shown in Figure 1, and a cartoon depiction of classification is shown in Figure 2. Multiresolution models have long been used for compact image representation[6], motion estimation[7], as well as classification and segmentation[8]. In [9], multiscale random fields are used for belief propagation through a quadtree hierarchy over an image. In [10], mixtures of treestructured belief networks are used for structural scene de-1.
CBTI-BP was associated with reduced risk of mood episode relapse and improved sleep and functioning on certain outcomes in bipolar disorder. Hence, sleep disturbance appears to be an important pathway contributing to bipolar disorder. The need to develop bipolar disorder-specific sleep diary scoring standards is highlighted.
