Everyday humans use cars to move faster, and the world is a chaotic place, and a little distraction or a mistake could be the reason for an accident and bring people great pain. An assistance system that can distinguish and detect signs on the roads and brings the driver's attention to road signs and make them aware of their meaning could be beneficial. The most important part of the Traffic Sign Recognition System is the algorithm. In this paper, a new way toward Traffic Sign Recognition algorithm taking the advantages of Color Segmentation, support vector machines, and histograms of oriented gradients on the GTSRB dataset is proposed. The unsupervised shuffled frog-leaping algorithm is employed for segmenting the images. The results show remarkable improvements by using meta-heuristic algorithms.
Understanding the behaviour of short-chain hydrocarbons confined to porous solids informs the targeted extraction of natural resources from geological features, and underpins rational developments in separation, storage and catalytic conversion processes. Herein, we report the application of low-field (12.7 MHz) 1H nuclear magnetic resonance (NMR) relaxation measurements to characterise ethane dynamics within mesoporous silica materials exhibiting mean pore diameters between 6 and 50 nm. Our measurements provide NMR-based adsorption isotherms within the range 25–50 bar and at ambient temperature, incorporating the ethane condensation point (40.7 bar at our experimental temperature of 23.6 °C). The quantitative nature of the acquired data is validated via a direct comparison of NMR-derived excess adsorption capacities with ex situ gravimetric ethane adsorption measurements, which are demonstrated to agree to within 0.2 mmol g−1 of the observed ethane capacity. NMR relaxation time distributions are further demonstrated as a means to decouple interparticle and mesopore dominated adsorption phenomena, with unexpectedly rapid relaxation rates associated with interparticle ethane gas confirmed via a direct comparison with NMR self-diffusion analysis. 相似文献
Nonlinear Dynamics - Rub–impact phenomenon occurring in hydrodynamic journal bearings is one of the main malfunctions in rotating machines and causes undesirable dynamic behavior. In order to... 相似文献
Ultrathin strained-Si/strained-Ge heterostructures on insulator have been fabricated using a bond and etch-back technique.
The substrate consists of a trilayer of 9 nm strained-Si/4 nm strained-Ge/3 nm strained-Si on a 400-nm-thick buried oxide.
The epitaxial trilayer structure was originally grown pseudomorphic to a relaxed Si0.5Ge0.5 layer on a donor substrate. Raman analysis of the as-grown and final transferred layer structures indicates that there is
little change in the strain in the Si and Ge layers after layer transfer. These ultrathin Si and Ge films have very high levels
of strain (∼1.8% biaxial tension and 1.4% compression, respectively), and are suitable for enhanced-mobility field-effect
transistor applications. 相似文献
We introduce the use of quantum dot (QD) nanoparticles for near-surface velocimetry and provide preliminary data to demonstrate its feasibility. Evanescent wave illumination is used to image the motion of water-soluble (CdSe)ZnS QDs with a core size of 6 nm within a region of order 100 nm of a surface . Results are presented for the two in-plane components of the velocity field. 相似文献
We present results for first molecular tagging velocimetry (MTV) measurements in water under resonant femtosecond excitation/emission process of a phosphorescent supramolecule. Both two-photon and three-photon absorption processes are examined, and the feasibility of measurements is demonstrated by single component velocimetry in a simple jet flow. The new capabilities enabled by FemtoMTV include elimination of the need for short wavelength UV excitation source and UV optical access in flow facilities, and potential for high rep-rate flow imaging. 相似文献
The equations governing plane steady-state flow in heterogeneous porous body containing cracks are presented first. Then,
a general transformation lemma is presented which allows extending a particular solution obtained for a given flow problem
to another configuration with different geometry, behaviour and boundary conditions. An existing potential solution in terms
of discharges along the cracks, established by Liolios and Exadaktylos (J Solids Struct 43:3960–3982, 2006) for non-intersecting
cracks in isotropic matrix, is extended to intersecting cracks in anisotropic matrix. The basic problem of a single straight
crack in an infinite body submitted to a pressure gradient at infinity is then investigated and a closed-form solution is
presented for the case of void cracks (infinite conductivity), as well as a semi-analytical solution for the case of cracks
with Poiseuille type conductivity. These solutions, derived first for an isotropic matrix, are then extended to anisotropic
matrices using the general transformation lemma. Finally, using the solution obtained for a single crack, a closed-form estimation
of the effective permeability of micro-cracked porous materials with weak crack density is derived from a self-consistent
upscaling scheme. 相似文献
Rock salt is considered as a pure aggregate of halite (mineral NaCl) crystals and its behaviour is investigated by a micro–macro approach. The behaviour of the polycrystalline aggregate is deduced from the properties of the constituent halite crystals. A model for the elastoplastic behaviour of halite crystal has been deduced from experimental data available in the literature. The basic equations of the micro–macro model for the polycrystalline medium and the calculation method are then presented and the elastoplastic behaviour of rock salt is investigated by this method. The hardening effects obtained for the polycrystal are found to be very different from those obtained for FCC metal polycrystals. The differences are explained as a consequence of differences of families of glide systems in these crystals. Finally, the internal stresses in the polycrystal are studied in order to elucidate the origin of cracking and damage of the rock salt. 相似文献
The potentiometric characteristics of a new Cu2+‐selective electrode based on 2‐(benzyliminomethyl)‐6‐methoxy‐4‐(4‐methoxyphenyl‐azo) phenol as an efficient ionophore has been evaluated. The effects of influential parameters on the potentiometric responses such as the amount of plasticizer, the amount of ionophore, pH of the sample solution, and the effect of coexisting ions on the electrode signal were subsequently investigated . The selectivity of the electrode was assessed by calculating the selectivity coefficients using the matched potential method. The optimum ratio of the amount of materials required for the preparation of the electrode was found to be 1.7: 32.1: 64.2: 2.0 corresponding to carboxylated PVC, dimethyl sebacate as solvent mediators, potassium tetrakis (p‐chlorophenyl) borate as the anion localizing agent, and ionophore, respectively. The electrode had a fast response (7s) as well as a satisfactory Nernstian slope (29.26±0.91 mV/decade) to Cu2+ over a wide concentration range of 2.0×10?6‐ 5.0×10?2 M with a low detection limit of 5.9×10?7 M. The developed sensor was successfully used for the potentiometric titration of Cu2+ ion with EDTA and subsequently, efficient determination of this metal ion in a mineral water sample was performed. 相似文献