We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna ...consists of a thin gold microdisk separated from a planar gold layer by a few tens of nanometers thick dielectric layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending on the antenna geometry. Considering the double dipole structure of the emitters, this corresponds to a Purcell factor up to 80 for dipoles perpendicular to the disk.
The paper discusses the stress gradient effect on crack initiation in fretting in medium cycle fatigue. The stress gradient effect is highlighted through fretting experiments in partial slip. Crack ...initiation is studied with an Inconel 718 cylinder plane contact. Tests are performed using three cylinder radii to sweep a large range of stress gradients. The experimental results confirm the stress gradient effect on crack initiation. A proposal is developed in a multiaxial fatigue framework to predict the experimental results. The proposal is based on a usual multiaxial fatigue criterion weighted by a weight function depending on the stress gradient. The model shows good capabilities to predict the crack initiation conditions for all contact configurations. The proposal is compared to other approaches.
The emergence of nanotechnology has stimulated a great deal of research to detect engineered nanoparticles spread out in the environment. We address this issue here by designing quantum dot-imprinted ...polymers for the speciation of nanoparticles based on their size, shape and surface chemistry.
Correction for 'Quantum dot-imprinted polymers with size and shell-selective recognition properties' by S. Gam-Derouich
et al., Chem. Commun.
, 2015, DOI:
10.1039/c5cc05203c
.
We described the engineering and characterization of photonic colloidal crystals based on silica spheres with incorporated YVO
4:Eu luminescent nanoparticles. These structures exhibit strong ...angle-dependent luminescent properties. The controlled incorporation of a planar defect in the periodic structures gives rise to the creation of a pass band in the pseudo-gap. In the energy range of this pass band, we observed a strong increase in combination with a sharp width of the emission spectrum, which opens new possibilities for the design of low-threshold and/or single mode photonic crystal lasers.
Magneto-Optical Study of Opal Thin Films Dung, Phan Tien; Nga, Pham Thu; Nhat, Hoang ...
IEEE transactions on magnetics,
10/2011, Letnik:
47, Številka:
10
Journal Article, Conference Proceeding
The structure and optical properties of artificial opal thin films, which were synthesized from silica spheres by a modified self-assembly protocol, in the absence and under the applied magnetic ...field were studied. The surface characterization showed a homogeneous well-ordered face centered cubic structure of silica balls at average size 305 ± 5 nm. The reflection measurements showed the main reflection plane (1 1 1) besides a minor secondary (2 0 0) plane. The applied field (up to 1000 Oe) induced a systematical splitting of several lines which showed an increase in intensity according to the increase in applied field and thickness of substrate coating MnO 2 layer.
This paper presents an engineering method to predict the spring-back of aircraft thick composite structures produced through an autoclaving process. The model previously developed by the same authors ...is firstly enhanced to be used in an aeronautic case study: an Airbus A350 rib. Results show that the out-of-plane shear stress distribution in the interface and the through-thickness in-plane normal stress gradient of the laminate are correctly represented. The interface is shown to have only a small influence on the final deformation and therefore a global model of the structure can be proposed. Finally a methodology is proposed to predict complex structures through a global-local approach.
Recent Convolutional Neural Network (CNN) has shown great potential in image classification, segmentation and object detection. Land cover takes advantage of CNN development for a large type of ...applications as water management and urban growing. However, to perform a land cover with numerous features – classes in classical CNN terminology, CNN models require a significant number of layers and neurons, resulting in high computational costs. To address this problem, a methodology is proposed in this paper to build a land cover using the aggregation of several CNN models. The overall process is based on 7 steps. The first two steps are the dataset creation and arrangement in smaller dataset fit for the specific features to detect. Then, a CNN architecture is built and validated on each sub-dataset corresponding to each class. Post-processing is conducted on each prediction before assembling the results. In the last step, a data cleaning is performed, giving the final land cover. The land cover of a rural area in Thailand is performed as a demonstration of the method, using satellite images with a resolution of 0.15 m/pixel. A 5-class (buildings, crops, forests, roads, and wastelands) dataset is created, consisting of a total of 1 million tiles of 64 × 64 pixels. The prediction results using the developed CNN model show an accuracy greater than 90% for each class, except for the road class where the accuracy only reaches 72%. Post-processing is performed on each of the 5 predictions. Only the 4 best results are retained and assembled to obtain the land cover, which generally corresponds to buildings, crops, forests, and wastelands. This method enables to identify by substitution with improved accuracy the last class whose prediction is the least accurate, and which generally corresponds to roads due to their small width relative to the tile size. The proposed methodology to perform a land cover by aggregating the prediction of different CNN models is found to predict correctly the land cover of two areas, especially roads can be classified, demonstrating the usefulness of the approach.
•A method to create a land cover is performed by aggregating different Convolutional Neural Network models.•A five class land cover is performed on rural area in Thailand as example.•Accuracy higher than of 90% are obtained excepted for the road class.•Overlapping process is used to reduce the classification area from 92 m2 to 5.76 m2
PDF
