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排序方式: 共有236条查询结果,搜索用时 328 毫秒
1.
Tallison O. Abreu Roterdan F. Abreu Felipe F. do Carmo Wellington V. de Sousa Helenilson de O. Barros José E.V. de Morais João P.C. do Nascimento Marcelo A.S. da Silva Sergei Trukhanov Alex Trukhanov Larissa Panina Charanjeet Singh Antonio S.B. Sombra 《Ceramics International》2021,47(11):15424-15432
This work presents the dielectric properties of YNbO4 (YNO)–TiO2 composites in the microwave range. X-ray diffraction analysis demonstrates that the addition of TiO2 to YNO results in the formation of a Y(Nb0.5Ti0.5)2O6 phase. In the microwave range, the values of permittivity and dielectric loss did not present major changes with the increment of TiO2. Moreover, the addition of TiO2 results in an improvement in the thermal stability of YNO, with YNO63 demonstrating a resonant frequency of ?8.96 ppm.°C?1. We utilised numerical simulations to evaluate the behaviour of these materials as dielectric resonator antennae and it is found that they exhibit a reflection coefficient below ?10 dB at the resonant frequency, with a realised gain of 4.94 – 5.76 dBi, a bandwidth of 665–1050 MHz and a radiation efficiency above 84%. Our results indicate that YNO–TiO2 composites are interesting candidates for microwave operating devices. 相似文献
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Magossi Maiara S. Maraldi Vitor A. Magossi Mariana S. DA Costa Fabíola M. Alves Kamilla Franco Fernanda D. S. DO Carmo Devaney R. 《SILICON》2021,13(7):2243-2255
Silicon - This study describes the preparation and characterization of 3-chloropropyl silica gel with 4-amino-5-(4pyridyl)-4H-1,2,4-triazole-3-thiol (SGA) for copper adsorption in different media.... 相似文献
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The goal of this paper is twofold : at first, to present the stochastic timed Pétri nets model by emphasizing its ability to express the main characteristics of real time distributed systems (parallelism, synchronization by message exchange, time attributes and in particular time constraints) and to allow both qualitative and quantitative analysis (concept of randomized states graph); second, to show a modeling methodology based on this model that allows a rigorous modeling of theDqdb protocol (Qa access, bwb mechanism role,Pa access influence). A new contribution to theQa mechanism has been done (1). 相似文献
6.
Electrocatalysts: Guided Evolution of Bulk Metallic Glass Nanostructures: A Platform for Designing 3D Electrocatalytic Surfaces (Adv. Mater. 10/2016)
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Gustavo Doubek Ryan C. Sekol Jinyang Li Won‐Hee Ryu Forrest S. Gittleson Siamak Nejati Eric Moy Candy Reid Marcelo Carmo Marcelo Linardi Punnathat Bordeenithikasem Emily Kinser Yanhui Liu Xiao Tong Chinedum O. Osuji Jan Schroers Sundeep Mukherjee André D. Taylor 《Advanced materials (Deerfield Beach, Fla.)》2016,28(10):1902-1902
7.
Luci Pirmez Jaime C. Carvalho Flávia C. Delicato Fábio Protti Luiz F.R.C. Carmo Paulo F. Pires Marcos Pirmez 《Computer Networks》2010,54(13):2117-2136
This work presents SUTIL, a mechanism for network selection in the context of next generation networks (NGN). SUTIL selection mechanism prioritizes networks with higher relevance to the application and lower energy consumption and it enables full and seamless connectivity to mobile user devices and applications. Consequently, SUTIL contributes to realize the vision of ubiquitous computing, in which services, devices, and sensor-enriched environments interact anytime, anywhere to accomplish human designed tasks. The provided solution is based on utility function and integer linear programming and it aims at: (i) maximizing the user satisfaction while meeting application QoS and (ii) minimizing the energy consumption of devices when connecting to a target network. The solution is global since it considers for a given base station all devices that are simultaneously candidate for handoff. Simulation results showed the benefits of SUTIL usage in NGN environments. 相似文献
8.
J. P. Carmo M. F. Silva J. F. Ribeiro R. F. Wolffenbuttel P. Alpuim J. G. Rocha L. M. Gon?alves J. H. Correia 《Microsystem Technologies》2011,17(8):1283-1291
This paper presents an approach for generating a well-defined cooling pattern over an area of tissue. An array of solid-state
microcoolers is used, which could be included in a probe that provides local cooling. This medical instrument can be used
for removal of scar tissue in the eye or for the rapid stopping of bleeding due to micro-cuts, which makes it a useful tool
to medical doctors and could make surgery more secure to the patient. The array of microcoolers is composed of 64 independent
thermo-electric elements, each controlled using an integrated circuit designed in CMOS. The independent control allows the
flexible programming of the surface temperature profile. This type of control is very suitable in case abrupt temperature
steps should be avoided. Cooling by lateral heat flow was selected in order to minimize the influence of heat by dissipation
from the electronic circuits. Moreover, a thermo-electric component with lateral heat allows fabrication of the cooling elements
using planar thin-film technology, lithography and wet etching on top of the silicon wafer. This approach is potentially CMOS
compatible, which would allow for the fabrication of the thermo-electric elements on top of a pre-fabricated CMOS wafer as
a post-process step. Each pixel is composed of thin-films of n-type bismuth telluride, Bi2Te3 and p-type antimony telluride, Sb2Te3, which are electrically interconnected as thermocouple. These materials have excellent thermoelectric characteristics, such
as thermoelectric figures-of-merit, ZT, at room temperatures of 0.84 and 0.5, respectively, which is equivalent to power-factors, PF, of 3.62 × 10−3 W K−1 m−2 and 2.81 × 10−3 W K−1 m−2, respectively. The theoretical study presented here demonstrates a cooling capability of 15°C at room temperature (300 K ≈ 27°C).
This cooling performance is sufficient to maintain a local tissue temperature at 25°C, which makes it suitable for the intended
application. A first prototype was successfully fabricated to demonstrate the concept. 相似文献
9.
Paulo Anselmo da Mota Silveira Neto Ivan do Carmo Machado John D. McGregorEduardo Santana de Almeida Silvio Romero de Lemos Meira 《Information and Software Technology》2011,53(5):407-423
Context
In software development, Testing is an important mechanism both to identify defects and assure that completed products work as specified. This is a common practice in single-system development, and continues to hold in Software Product Lines (SPL). Even though extensive research has been done in the SPL Testing field, it is necessary to assess the current state of research and practice, in order to provide practitioners with evidence that enable fostering its further development.Objective
This paper focuses on Testing in SPL and has the following goals: investigate state-of-the-art testing practices, synthesize available evidence, and identify gaps between required techniques and existing approaches, available in the literature.Method
A systematic mapping study was conducted with a set of nine research questions, in which 120 studies, dated from 1993 to 2009, were evaluated.Results
Although several aspects regarding testing have been covered by single-system development approaches, many cannot be directly applied in the SPL context due to specific issues. In addition, particular aspects regarding SPL are not covered by the existing SPL approaches, and when the aspects are covered, the literature just gives brief overviews. This scenario indicates that additional investigation, empirical and practical, should be performed.Conclusion
The results can help to understand the needs in SPL Testing, by identifying points that still require additional investigation, since important aspects regarding particular points of software product lines have not been addressed yet. 相似文献10.
This paper presents a flexible thin-film (FTF) composed by a photovoltaic (PV) cell, a flexible solid-state rechargeable battery and power management electronics. A flexible printed circuit board (fPCB) was used for providing physical support to the electronics and to the battery, whereas a PDMS (polydimethylsiloxane) layer was used for providing mechanical adhesion between the PV cell and the fPCB. The high elasticity of the PDMS makes this material an excellent candidate for adapting two materials with different thermal expansions (fPCB and PV). The physical measurements showed a prototype with a thickness in the range 1.52 ± 0.10 mm, 10 g of weight and 37 × 114 mm of size. The electrical measurements showed ability to provide an output voltage of 3.8 V in a continuously form under these conditions: the PV providing DC power for solar irradiations higher than 6 W m−2, and the battery providing DC power for solar irradiations above bellow 6 W m−2 (value that has emerged during the twilight between sunset and dusk). 相似文献