Journal of Computational Electronics - Zigzag and armchair graphene nanoribbons (ZGNR and AGNR) have been investigated using the density functional theory (DFT) and nonequilibrium Green’s... 相似文献
Objective To investigate the kinetics of Iododeoxyuridine (IUdR)release from sodium alginate hydrogel cross-linked with varying amounts of calcium chloride, and to optimize sustained release for further periadventitial I125-labeled IUdR 相似文献
High-temperature superconductors (HTSs) are important for potential applications and for understanding the origin of strong correlations. Bi2Sr2CaCu2O8+δ (BSCCO), a van der Waals material, offers a platform to probe the physics down to a unit-cell. Guiding the flow of electrons by patterning 2DEGS and oxide heterostructures has brought new functionality and access to new science. Similarly, modifying superconductivity in HTS locally, on a small length scale, is of immense interest for superconducting electronics. A route to modify superconductivity locally by depositing metal on the surface is reported here by transport studies on few unit-cell thick BSCCO. Deposition of chromium (Cr) on the surface over a selected area of BSCCO results in insulating behavior of the underlying region. Cr locally depletes oxygen in CuO2 planes and disrupts the superconductivity in the layers below. This technique of modifying superconductivity is suitable for making sub-micrometer superconducting wires and more complex superconducting devices. 相似文献
We have investigated strain-induced spin lattice coupling in the CoFe2O4/0.65Pb (Mg1/3Nb2/3)O3–0.35PbTiO3(PMN-PT) composite system, evident by temperature-dependent Raman spectroscopy and magnetization measurements. The strain interactions lead to magneto-electric coupling, and the measured magneto-electric voltage coefficient is 40 mV/cm?1Oe?1 for the CoFe2O4/PMN-PT composite samples. X-ray magnetic circular dichroism (XMCD) analysis establishes modified spin structure in the electrically poled CoFe2O4/PMN-PT composite, further validating the coupling between magnetic and electric ordering in the composite. The magneto-electric coupling coefficient α vs dc magnetic field curves revealed hysteretic behavior and enhanced α values after electric poling, which originates from the strain-induced modifications in the magnetic structure of composite in the electrically poled samples. These findings suggest that the existence of spin lattice coupling may lead to the mechanism of strong magneto-electric effects via strain interactions in CoFe2O4/PMN-PT composite.
Tensile membrane structures (TMS) are light-weight flexible structures that are designed to span long distances with structural efficiency. The stability of a TMS is jeopardised under heavy wind forces due to its inherent flexibility and inability to carry out-of-plane moment and shear. A stable TMS under uncertain wind loads (without any tearing failure) can only be achieved by a proper choice of the initial prestress. In this work, a double-loop reliability-based design optimisation (RBDO) of TMS under uncertain wind load is proposed. Using a sequential polynomial chaos expansion (PCE) and kriging based metamodel, this RBDO reduces the cost of inner-loop reliability analysis involving an intensive finite element solver. The proposed general approach is applied to the RBDO of two benchmark TMS and its computational efficiency is demonstrated through these case studies. The method developed here is suggested for RBDO of large and complex engineering systems requiring costly numerical solution. 相似文献
We report single-molecule-transistor measurements on devices incorporating magnetic molecules. By studying the electron-tunneling spectrum as a function of magnetic field, we are able to identify signatures of magnetic states and their associated magnetic anisotropy. A comparison of the data to simulations also suggests that sequential electron tunneling may enhance the magnetic relaxation of the magnetic molecule. 相似文献
Polycrystalline nano BiFeO3 powders were synthesized by auto-combustion method using urea as fuel and metal nitrates (Fe(NO3)3·9H2O, Bi(NO3)3·5H2O) as oxidizers. In order to optimize the single-phase synthesis condition of BiFeO3, different fuel to oxidizer ratios have been investigated. The preliminary structural investigation using X-ray diffraction shows the samples were of single phase and crystallize in rhombohedral structure (R3c). The ferroelectric and antiferromagnetic ordering temperatures of BiFeO3 were found to be 832 °C and 364 °C respectively, from differential thermal analysis. The temperature dependent dielectric study shows an anomaly around 215 °C which corresponds to magneto-electric coupling in the material. Field-emission scanning electron micrographs show effect of fuel to oxidizer ratio on grain size evolution. The ferroelectric hysteresis loops for all the samples were measured at a frequency of 100 Hz confirming the ferroelectric nature. An evidence of magneto-electric coupling was also observed at room temperature from magneto-capacitance measurements. 相似文献
Hands-on inquiry-based educational modules were designed for two undergraduate geotechnical engineering courses at the University of Vermont. The modules were designed to achieve three objectives: (1) meet the goals of our ongoing civil and environmental engineering curricular reform (e.g., inquiry-based experiential learning and civic engagement through service-learning); (2) reach higher levels of Bloom’s taxonomy in specific topical areas addressed by the modules; and (3) help achieve Accreditation Board for Engineering and Technology (ABET) outcomes for civil and environmental engineering programs. All four modules were conducted within team settings and required students to write formal technical papers or reports followed by presentations. An additional underlying objective was the development of students’ interpersonal and communication skills. The educational modules included: (1) Atterberg limits using Casagrande and fall cone devices; (2) physical, analytical, and numerical modelings of steady-state seepage; (3) validation of undrained slope stability, bearing capacity of shallow foundations, and active and passive lateral earth pressure analytical solutions using centrifuge modeling; and (4) service-learning projects related to foundations, retaining structures, or slope stability for rehabilitation of historic structures. Student reflection and self-assessment activities were conducted. The student self-assessment results and assessments of student work indicated that many of the curricular reform objectives, ABET outcomes, and higher levels of Bloom’s taxonomy could be reached through these modules. Modules similar to these could be effective in other engineering disciplines and subdisciplines. 相似文献
Twitter (http://twitter.com) is one of the most popular social networking platforms. Twitter users can easily broadcast disaster-specific information, which, if effectively mined, can assist in relief operations. However, the brevity and informal nature of tweets pose a challenge to Information Retrieval (IR) researchers. In this paper, we successfully use word embedding techniques to improve ranking for ad-hoc queries on microblog data. Our experiments with the ‘Social Media for Emergency Relief and Preparedness’ (SMERP) dataset provided at an ECIR 2017 workshop show that these techniques outperform conventional term-matching based IR models. In addition, we show that, for the SMERP task, our word embedding based method is more effective if the embeddings are generated from the disaster specific SMERP data, than when they are trained on the large social media collection provided for the TREC (http://trec.nist.gov/) 2011 Microblog track dataset. 相似文献
Fragmentation of proppant particles in a pack subjected to compressive loading results in a loss of load bearing capacity. Addition of ductile particles to a brittle particle pack reduces particle fragmentation. Computational models simulating confined compression of a proppant pack with a mixture of brittle and ductile particles are developed. The effect of soft particle material, shape, and size on the fragmentation behavior of the brittle particle in a proppant pack is studied. The results showed that larger, nonuniform particles lead to higher incidence of particle fracture. More efficient pack compositions are proposed for further study and development. 相似文献