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排序方式: 共有320条查询结果,搜索用时 15 毫秒
1.
V. Iakovlev G. Suruceanu A. Caliman A. Mereuta A. Mircea C.-A. Berseth A. Syrbu A. Rudra E. Kapon 《Photonics Technology Letters, IEEE》2005,17(5):947-949
High-performance vertical-cavity surface-emitting lasers (VCSELs) emitting in the 1310-nm waveband are fabricated by bonding AlGaAs-GaAs distributed Bragg reflectors on both sides of a InP-based cavity. A 2-in wafer bonding process is optimized to produce very good on-wafer device parameter uniformity. Carrier injection is implemented via double intracavity contact layers and a tunnel junction. A 1.2-mW single-mode output power is obtained in the temperature range of 20/spl deg/C-80/spl deg/C. Modulation capability at 3.2 Gb/s is demonstrated up to 70/spl deg/C. Overall VCSEL performance complies with the requirements of the 10 GBASE-LX4 IEEE.802.3ae standard, which opens the way for novel applications of VCSELs emitting in the 1310-nm band. 相似文献
2.
Chorda tympani nerve (CT) transection in rats severely impairs NaCl taste detection. These rats can detect higher concentrations of NaCl, however, suggesting that remaining oral nerves maintain some salt sensibility. Rats were tested in a gustometer with a 2-response operant taste-detection task before and after sham surgery (n = 5), combined transection of the CT and the greater superficial petrosal nerves (GSP; 7x, n = 6), or transection of the glossopharyngeal nerve (GL; 9x, n = 4). Thresholds did not significantly change after sham surgery. Although the GL responds to NaCl and innervates nearly 60% of total taste buds, 9x surgery had no effect. However, 7x surgery increased NaCl detection threshold by ~2.5 log?? units, greater than that reported for CT transection alone. These results suggest that the GSP contributes to NaCl sensitivity in rats and also demonstrate that the GL and perhaps the superior laryngeal and lingual nerve proper can maintain some NaCl detectability at high concentrations. These findings confirm the primacy of the 7th nerve relative to the 9th nerve in sensibility of NaCl in the rat model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Aniello Leonardo Halak Basel Chai Peter Dhall Riddhi Mihalea Mircea Wilczynski Adrian 《International Journal of Information Security》2021,20(3):445-460
International Journal of Information Security - The complexity of today’s integrated circuit (IC) supply chain, organised in several tiers and including many companies located in different... 相似文献
4.
The paper treats the control problem of a class of robots constituted by a chain of continuum segments. The technological model basis is a central, long and thin, highly flexible and elastic backbone. The segment control system is a decoupled one. The main parameters of the arm control are determined by the curvature and curvature gradient. The dynamic model is inferred. The primary benefit of the proposed method is that the dynamic equations are represented by a set of ODE’s in time instead of PDE’s in time and space, and the new curvature gradient lumped parameter model is used. A sliding mode control system is used in order to achieve the desired shape of the arm. The stability of the closed-loop control system is proven. Numerical simulations and an experimental platform are also provided to verify the effectiveness of the presented approach. 相似文献
5.
Alireza Tavakkoli Mircea Nicolescu George Bebis Monica Nicolescu 《Machine Vision and Applications》2009,20(6):395-409
Most methods for foreground region detection in videos are challenged by the presence of quasi-stationary backgrounds—flickering
monitors, waving tree branches, moving water surfaces or rain. Additional difficulties are caused by camera shake or by the
presence of moving objects in every image. The contribution of this paper is to propose a scene-independent and non-parametric
modeling technique which covers most of the above scenarios. First, an adaptive statistical method, called adaptive kernel
density estimation (AKDE), is proposed as a base-line system that addresses the scene dependence issue. After investigating
its performance we introduce a novel general statistical technique, called recursive modeling (RM). The RM overcomes the weaknesses
of the AKDE in modeling slow changes in the background. The performance of the RM is evaluated asymptotically and compared
with the base-line system (AKDE). A wide range of quantitative and qualitative experiments is performed to compare the proposed
RM with the base-line system and existing algorithms. Finally, a comparison of various background modeling systems is presented
as well as a discussion on the suitability of each technique for different scenarios. 相似文献
6.
This paper presents a test platform for the scale modeling of electromagnetic pulse effects. The different elements of the installation, i.e. a vertical conical antenna placed on a metallic reference plane, a fast rise time supply generator and a data acquisition and processing facility are described. The field of the antenna has also been studied using a Numerical Electromagnetic Code (Nec)based on the moments method and a comparison with the measurements has been performed. Conclusions resulting from this first stage in the construction of the scale modeling installation are presented. 相似文献
7.
Mircea Popescu 《Electrical Engineering (Archiv fur Elektrotechnik)》2006,89(2):117-125
For the calculation of torque in synchronous motors a local method is analysed, based on the Maxwell stress theory and the
filtered contributions due to the harmonics of the magnetic vector potential in the motor air-gap. By considering the space
fundamental field only, the method can efficiently estimate the average synchronous torque for a variety or motor topologies,
including concentrated winding designs. This approach employs an analytical filter for the Maxwell stress tensor and `frozen
permeability' technique. The proposed method is validated by comparison with FE results for several synchronous motor types:
interior permanent magnet motors, wound field motor, synchronous reluctance motor. 相似文献
8.
A two part probabilistic model for polycrystalline microstructures is described. The model utilizes a Poisson–Voronoi tessellation for the grain geometry and a vector random field model for the crystallographic orientation. The grain geometry model is calibrated to experimental data through the intensity of the Poisson point field underlying the Poisson–Voronoi tessellation and the orientation random field is calibrated to experimental data through its marginal distributions and second moment properties. Realizations of the random microstructure are generated by use of translation methods and are used, with simplified mechanical models, to investigate the problem of intergranular fracture. It is found that intergranular cracks exhibit some statistical properties of a scaled Brownian motion process. 相似文献
9.
Federico Waisman Kurtis Gurley Mircea Grigoriu Ahsan Kareem 《Canadian Metallurgical Quarterly》2002,128(7):730-741
Significant interest has been shown in identifying the nonlinear mechanisms that induce a ringing type response in offshore structural systems. This high frequency transient type response has been observed in offshore systems, particularly in tension leg platforms (TLPs). Given the implications of this behavior on the fatigue life of TLP tendons, it is essential that ringing be considered in the overall response evaluation. This study presents two non-Gaussian probabilistic models of nonlinear viscous hydrodynamic wave forces that induce ringing. The response of a single-degree-of-freedom system exposed to these non-Gaussian wave force models is then evaluated using analytical and numerical studies based on the It? differentiation rule and the Monte Carlo simulation procedure, respectively. The results demonstrate that the proposed models induce ringing type response in a simplified structure. This study provides a probabilistic framework for modeling ringing type phenomenon which will serve as a building block for more refined hydrodynamic load models. 相似文献
10.
Claudia Mihaela Ninciuleanu Raluca Ianchi Elvira Alexandrescu Ctlin Ionu Mihescu Sabina Burlacu Bogdan Tric Cristina Lavinia Nistor Silviu Preda Cristina Scomoroscenco Ctlina Gîfu Cristian Petcu Mircea Teodorescu 《International journal of molecular sciences》2022,23(18)
The present work aims to show how the main properties of poly(methacrylic acid) (PMAA) hydrogels can be engineered by means of several silicon-based fillers (Laponite XLS/XLG, montmorillonite (Mt), pyrogenic silica (PS)) employed at 10 wt% concentration based on MAA. Various techniques (FT-IR, XRD, TGA, SEM, TEM, DLS, rheological measurements, UV-VIS) were used to comparatively study the effect of these fillers, in correlation with their characteristics, upon the structure and swelling, viscoelastic, and water decontamination properties of (nano)composite hydrogels. The experiments demonstrated that the nanocomposite hydrogel morphology was dictated by the way the filler particles dispersed in water. The equilibrium swelling degree (SDe) depended on both the pH of the environment and the filler nature. At pH 1.2, a slight crosslinking effect of the fillers was evidenced, increasing in the order Mt < Laponite < PS. At pH > pKaMAA (pH 5.4; 7.4; 9.5), the Laponite/Mt-containing hydrogels displayed a higher SDe as compared to the neat one, while at pH 7.4/9.5 the PS-filled hydrogels surprisingly displayed the highest SDe. Rheological measurements on as-prepared hydrogels showed that the filler addition improved the mechanical properties. After equilibrium swelling at pH 5.4, G’ and G” depended on the filler, the Laponite-reinforced hydrogels proving to be the strongest. The (nano)composite hydrogels synthesized displayed filler-dependent absorption properties of two cationic dyes used as model water pollutants, Laponite XLS-reinforced hydrogel demonstrating both the highest absorption rate and absorption capacity. Besides wastewater purification, the (nano)composite hydrogels described here may also find applications in the pharmaceutical field as devices for the controlled release of drugs. 相似文献