973 resultados para pre-emphasis technique
Resumo:
Inaccuracies in prediction of circulating viral strain genotypes and the possibility of novel reassortants causing a pandemic outbreak necessitate the development of an anti-influenza vaccine with increased breadth of protection and potential for rapid production and deployment. The hemagglutinin (HA) stem is a promising target for universal influenza vaccine as stem-specific antibodies have the potential to be broadly cross-reactive towards different HA subtypes. Here, we report the design of a bacterially expressed polypeptide that mimics a H5 HA stem by protein minimization to focus the antibody response towards the HA stem. The HA mini-stem folds as a trimer mimicking the HA prefusion conformation. It is resistant to thermal/chemical stress, and it binds to conformation-specific, HA stem-directed broadly neutralizing antibodies with high affinity. Mice vaccinated with the group 1 HA mini-stems are protected from morbidity and mortality against lethal challenge by both group 1 (H5 and H1) and group 2 (H3) influenza viruses, the first report of cross-group protection. Passive transfer of immune serum demonstrates the protection is mediated by stem-specific antibodies. Furthermore, antibodies indudced by these HA stems have broad HA reactivity, yet they do not have antibody-dependent enhancement activity.
Resumo:
Constant-volts-per-hertz induction motor drives and vector-controlled induction motor drives utilize pulsewidth modulation (PWM) to control the voltage applied on the motor. The method of PWM influences the pulsations in the torque developed by the motor. A space-vector-based approach to PWM facilitates special switching sequences involving the division of active state time. This paper proposes a space-vector-based hybrid PWM technique, which is a combination of the conventional and special switching sequences. The proposed hybrid PWM technique results in a lower peak-to-peak torque ripple than conventional space vector PWM(CSVPWM) at high speeds of an induction motor drive. Furthermore, the magnitude of the dominant torque harmonic due to the proposed hybrid PWM is significantly lower than that due to CSVPWM at high speeds of the drive. Experimental results from a 3.75-kW sensorless vector-controlled induction motor drive under various load conditions are presented to support analytical and simulation results.
Resumo:
Acoustic feature based speech (syllable) rate estimation and syllable nuclei detection are important problems in automatic speech recognition (ASR), computer assisted language learning (CALL) and fluency analysis. A typical solution for both the problems consists of two stages. The first stage involves computing a short-time feature contour such that most of the peaks of the contour correspond to the syllabic nuclei. In the second stage, the peaks corresponding to the syllable nuclei are detected. In this work, instead of the peak detection, we perform a mode-shape classification, which is formulated as a supervised binary classification problem - mode-shapes representing the syllabic nuclei as one class and remaining as the other. We use the temporal correlation and selected sub-band correlation (TCSSBC) feature contour and the mode-shapes in the TCSSBC feature contour are converted into a set of feature vectors using an interpolation technique. A support vector machine classifier is used for the classification. Experiments are performed separately using Switchboard, TIMIT and CTIMIT corpora in a five-fold cross validation setup. The average correlation coefficients for the syllable rate estimation turn out to be 0.6761, 0.6928 and 0.3604 for three corpora respectively, which outperform those obtained by the best of the existing peak detection techniques. Similarly, the average F-scores (syllable level) for the syllable nuclei detection are 0.8917, 0.8200 and 0.7637 for three corpora respectively. (C) 2016 Elsevier B.V. All rights reserved.
Resumo:
Present paper is the first one in the series devoted to the dynamics of traveling waves emerging in the uncompressed, tri-atomic granular crystals. This work is primarily concerned with the dynamics of one-dimensional periodic granular trimer (tri-atomic) chains in the state of acoustic vacuum. Each unit cell consists of three spherical particles of different masses subject to periodic boundary conditions. Hertzian interaction law governs the mutual interaction of these particles. Under the assumption of zero pre-compression, this interaction is modeled as purely nonlinear, which means the absence of linear force component. The dynamics of such chains is governed by the two system parameters that scale the mass ratios between the particles of the unit cell. Such a system supports two different classes of periodic solutions namely the traveling and standing waves. The primary objective of the present study is the numerical analysis of the bifurcation structure of these solutions with emphasis on the dynamics of traveling waves. In fact, understanding of the bifurcation structure of the traveling wave solutions emerging in the unit-cell granular trimer is rather important and can shed light on the more complex nonlinear wave phenomena emerging in semi-infinite trimer chains. (c) 2016 Elsevier B.V. All rights reserved.
Resumo:
The polyhedral model provides an expressive intermediate representation that is convenient for the analysis and subsequent transformation of affine loop nests. Several heuristics exist for achieving complex program transformations in this model. However, there is also considerable scope to utilize this model to tackle the problem of automatic memory footprint optimization. In this paper, we present a new automatic storage optimization technique which can be used to achieve both intra-array as well as inter-array storage reuse with a pre-determined schedule for the computation. Our approach works by finding statement-wise storage partitioning hyper planes that partition a unified global array space so that values with overlapping live ranges are not mapped to the same partition. Our heuristic is driven by a fourfold objective function which not only minimizes the dimensionality and storage requirements of arrays required for each high-level statement, but also maximizes inter statement storage reuse. The storage mappings obtained using our heuristic can be asymptotically better than those obtained by any existing technique. We implement our technique and demonstrate its practical impact by evaluating its effectiveness on several benchmarks chosen from the domains of image processing, stencil computations, and high-performance computing.
Resumo:
Measurement while drilling (MWD) has become a popular survey technology to monitor directional data, drilling data, formation evaluation data and safety data in the world. And closed loop drilling shows promise in recent years. Obviously, the method of tr
Resumo:
The property of crystal depends seriously on the solution concentration distribution near the growth surface of a crystal. However, the concentration distributions are affected by the diffusion and convection of the solution. In the present experiment, the two methods of optical measurement are used to obtained velocity field and concentration field of NaClO3 solution. The convection patterns in sodium chlorate (NaClO3) crystal growth are measured by Digital Particle image Velocimetry (DPIV) technology. The 2-dimentional velocity distributions in the solution of NaClO3 are obtained from experiments. And concentration field are obtained by a Mach-Zehnder interferometer with a phase shift servo system. Interference patterns were recorded directly by a computer via a CCD camera. The evolution of velocity field and concentration field from dissolution to crystallization are visualized clearly. The structures of velocity fields were compared with that of concentration field.
Resumo:
In the previous paper, a class of nonlinear system is mapped to a so-called skeleton linear model (SLM) based on the joint time-frequency analysis method. Behavior of the nonlinear system may be indicated quantitatively by the variance of the coefficients of SLM versus its response. Using this model we propose an identification method for nonlinear systems based on nonstationary vibration data in this paper. The key technique in the identification procedure is a time-frequency filtering method by which solution of the SLM is extracted from the response data of the corresponding nonlinear system. Two time-frequency filtering methods are discussed here. One is based on the quadratic time-frequency distribution and its inverse transform, the other is based on the quadratic time-frequency distribution and the wavelet transform. Both numerical examples and an experimental application are given to illustrate the validity of the technique.
Resumo:
The aggregation behaviors of two surfactants with the same hydrophobic tail, sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium bis(2-ethylhexyl)phosphate (NaDEHP), have been investigated by the fluorescence technique and z-potential (ζ) measurements. Five fine peaks of the pyrene molecule fluorescence spectroscopy appear in the surfactant solution, and the micropolarity at which pyrene locates is monitored from the intensity ratio of the first (I1) and the third peak (I3). A wide peak around 475 nm, the emission spectra of the excimer of pyrene molecules, is observed in the NaDEHP solution, while this is not found for the AOT system. The value of I1/I3 decreases in a more limited concentration range for the AOT system than for NaDEHP, indicating that small aggregates can be more easily formed by NaDEHP molecules. The z-potential results for the aggregates formed by the two surfactants show that the interaction between AOT and PVP is stronger than that between NaDEHP and PVP.
Resumo:
We report a detailed study of surface-bound chemical vapor deposition of carbon nanotubes and nanofibers from evaporated transition metal catalysts exposed to ammonia diluted acetylene. We show that a reduction of the Fe/Co catalyst film thickness below 3 nm results into a transition from large diameter (> 40 nm), bamboo-like nanofibers to small diameter (similar to 5 nm) multi-walled carbon nanotubes. The nanostructuring of ultrathin catalyst films critically depends on the gas atmosphere, with the resulting island distribution initiating the carbon nucleation. Compared to purely thermal chemical vapor deposition, we find that, for small diameter nanotube growth, DC plasma assistance is detrimental to graphitization and sample homogeneity and cannot prevent an early catalyst poisoning. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
En el presente trabajo se evaluó EX-ante la factibilidad técnica y financiera de una propuesta de desarrollo ganadero para la finca "El Garabato" planteada por los socios de la Cooperativa Ezequiel N24 en el Municipio de Tola, Departamento de Rivas. Para ello se realizó un diagnóstico general de la finca, donde se determinó los recursos disponibles y las características propias del sistema productivo, basados en esto se estimaron los diferentes coeficientes técnicos así como las posibles fuentes de ingresos y egresos, permitiendo realizar las proyecciones del hato así como las proyecciones financieras, Dentro de los aspectos técnicos se determinó la composición de las pasturas donde el 69% de los pastos son naturalizados, el 23% son pastos mejorados y el 8% está conformado por pastos naturales. Los canales de comercialización en la zona del proyecto para la leche están representados por los manteros, el Proyecto Juan Agustín Guillén de la Tienda Campesina y el Centro de Acopio de La Selecta. En el caso de la carne por los intermediarios (matarifes) y productores dedicados a la crianza y engorde de novillos. Al considerar las inversiones en pastura que conlleva la propuesta, la distribución de pastos varia, ocupando los pastos mejorados el 41%, el 3% por pastos naturales y el 56% corresponden a pastos naturalizados. A la par de esto el área ganadera se incrementa en 64 mz. como consecuencia de la reducción del área agricola por la misma cantidad de mz. Las disponibilidades de pastos se ven mejoradas por las inversiones, disminuyendo el déficit de alimento a partir del segundo año. El uso de la Caña de Azúcar más urea, durante el verano permitirá mejorar la oferta de alimento para esta época, resultando menores pérdidas en la producción. Como efecto de la propuesta se producirá un incremento promedio anual de 7.18% del hato total, este incremento se da esperando que los índices de mortalidad de adultos y terneros disminuyan de un 4 al. 2% y de 14 al 7% respectivamente y que la tasa de descarte de vacas se mantenga en 12%1 considerando que la finca mantenga un 67% en tasa de natalidad. Al estructurar los gastos se encontró que en el año base los gastos de mano de obra representan el 71%, la suplementación el 8%, los gastos en manejo fueron de 8%, impuestos 7%, mantenimiento de equipo e infraestructura de 4% y gastos varios de 1%, con el proyecto esta estructura de gastos se ve un poco alterada al disminuir los gastos por mano de obra a un 63% e incrementarse los gastos por suplementacion y gastos varios a 12% y 6% respectivamente, el resto de los gastos presentan leves modificaciones. En los ingresos del año base la producción de leche representa el 46%, la producción de carne el 53% y el 1% corresponde a otros ingresos. Con el proyecto el aporte en los ingresos por producción de leche asciende a 62% y en producción de carne es de 34%, en otros ingresos representa el 4% al finalizar el sexto año. De las inversiones que se realizaran el 60% ésta destinado para pastos y el 40% corresponde a inversiones en infraestructura. El monto total de la inversión asciende a C$96,905.70 de los cuales el 71% será solicitado en préstamo y el restante 29% será asumido por la Cooperativa. Del análisis financiero resultó que la propuesta de los socios con uso de financiamiento para las inversiones a una tasa de interés del 12.5% presenta un VAN de C$41996.65 y una TIR de 15.16%. En cambió la realización de la propuesta con recursos propios presentó resultados superiores al anterior siendo el VAN de C$18,506.01 y una TIR de 18.01%•. Considerando estos resultados la propuesta es rentable, pero debido al déficit de efectivo que se presenta en los primeros años podría alterar la realización de las inversiones, ésta situación puede compensarse haciendo uso de otros recursos de la Cooperativa.
Resumo:
In this paper, a nano-moiré fringe multiplication method is proposed, which can be used to measure nano-deformation of single crystal materials. The lattice structure of Si (111) is recorded on a film at a given magnification under a transmission microscope, which acts as a specimen grating. A parallel grating (binary type) on glass or film is selected as a reference grating. A multiplied nano-moiré fringe pattern can be reproduced in a 4f optical filter system with the specimen grating and the prepared reference grating. The successful results illustrate that this method can be used to measure deformation in nanometre scale. The method is especially useful in the measurement of the inhomogeneous displacement field, and can be utilized to characterize nano-mechanical behaviour of materials such as dislocation and atomic bond failure.
Resumo:
Con el objetivo de caracterizar la curva de lactancia y evaluar el comportamiento reproductivo se analizaron los registros mensuales (N=10) de vaquillas Holstein bajo la implementación y falta de implementación de medidas de manejo pre-parto en la Empresa Agropecuaria “San Ignacio” Mateare, Nicaragua. Para caracterizar la curva de lactancia, se utilizó el modelo de Wood (1967) de forma linealizada Ln Yx = Lna + b Lnx - ex , donde Yx es la producción diaria en el período x, a representa la producción inicial, b el ascenso al pico, c el descenso de producción, a partir del mismo se generaron la Persistencia (S), Rendimiento al pico (RP), Tiempo al pico (TP), también se evaluó el Intervalo parto - concepción (IPC) y el Número de servicios por concepción (NSPC) . Al presentar problemas reproductivos la proporción de curvas atípicas encontradas en este Trabajo fue de 40%. Al analizar la curva de lactancia del grupo experimental se observa un a= 11.00212 kg, b = 0.083528 kg, e = 0.00407148 kg, RP = 12.790 kg, TP = 29.54 días, S = 6.126. El grupo testigo presenta un a = 6.4384 kg, b = 0.193048 kg, e = 0.00466974 kg, RP = 9.49 kg, TP = 34.32 días, S = 6.421. En el análisis de varianza se encontró que el RP tiene diferencia significativa entre los tratamientos a un nivel de significancia (P<0.05). Los parámetros reproductivos IPC y NSPC para el grupo experimental fueron de 243.6 días y 3 servicios respectivamente, el grupo testigo presentó un IPC = 221.8 días y NSPC = 3.6 servicios .
Characterization of a Laser-Discrete Quenched Steel Substrate/Chromium System by Dissolving Coatings
Resumo:
A laser-discrete quenched steel (LDQS) substrate/as-deposited chromium (top high-contraction (HC) and underlying low-contraction (LC) chromium) system was investigated by dissolving coatings in order to reveal the mechanism that the service life of the coated parts is largely improved using the hybrid technique of laser pre-quenching plus chromium post-depositing. It was found that the surface characteristics of the substrate, LC and HC chromium layer can be simultaneously revealed owing to the dissolution edge effect of chromium coatings. Moreover, the periodical gradient morphologies of the LDQS substrate are clearly shown: the surfaces of laser transformation-hardened regions are rather smooth; a lot of fine micro-holes exist in the transition zones; there are many micro-dimples in the original substrate. Furthermore, the novel method of dissolving coatings with sharp interfaces may be used to reveal the structural features of a substrate/coating system, explore the effect of the substrate on the initial microstructure and morphologies of coatings, and check the quality of the coated-parts.