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排序方式: 共有3696条查询结果,搜索用时 15 毫秒
61.
Natalya N. Barabanova Victor V. Belyaev Dmitriy L. Bogdanov Vladimir G. Chigrinov Artem K. Dadivanyan Artem P. Nazarov Olga V. Noah 《Journal of the Society for Information Display》2015,23(10):486-490
A method of controlling anchoring energy of surface interaction of liquid crystal photoaligning substances is considered to enhance the liquid crystal display performances. An important parameter of the dye's molecular structure that determines the ratio of polar and azimuthal anchoring energy is the ability to form dimers. The values of dimerization thermodynamic potentials have been found. The probability of the formation of dye molecules dimers is evaluated. The bonds conjugation transfer via intermolecular hydrogen bond is revealed, and anisotropy of polarizability of the hydrogen bond is evaluated. The effect of dimerization on polar and azimuthal anchoring energy of liquid crystal — azo dye system — is shown. 相似文献
62.
Extracting Microfacet‐based BRDF Parameters from Arbitrary Materials with Power Iterations 下载免费PDF全文
Jonathan Dupuy Eric Heitz Jean‐Claude Iehl Pierre Poulin Victor Ostromoukhov 《Computer Graphics Forum》2015,34(4):21-30
We introduce a novel fitting procedure that takes as input an arbitrary material, possibly anisotropic, and automatically converts it to a microfacet BRDF. Our algorithm is based on the property that the distribution of microfacets may be retrieved by solving an eigenvector problem that is built solely from backscattering samples. We show that the eigenvector associated to the largest eigenvalue is always the only solution to this problem, and compute it using the power iteration method. This approach is straightforward to implement, much faster to compute, and considerably more robust than solutions based on nonlinear optimizations. In addition, we provide simple conversion procedures of our fits into both Beckmann and GGX roughness parameters, and discuss the advantages of microfacet slope space to make our fits editable. We apply our method to measured materials from two large databases that include anisotropic materials, and demonstrate the benefits of spatially varying roughness on texture mapped geometric models. 相似文献
63.
Victor Picheny Tobias Wagner David Ginsbourger 《Structural and Multidisciplinary Optimization》2013,48(3):607-626
Responses of many real-world problems can only be evaluated perturbed by noise. In order to make an efficient optimization of these problems possible, intelligent optimization strategies successfully coping with noisy evaluations are required. In this article, a comprehensive review of existing kriging-based methods for the optimization of noisy functions is provided. In summary, ten methods for choosing the sequential samples are described using a unified formalism. They are compared on analytical benchmark problems, whereby the usual assumption of homoscedastic Gaussian noise made in the underlying models is meet. Different problem configurations (noise level, maximum number of observations, initial number of observations) and setups (covariance functions, budget, initial sample size) are considered. It is found that the choices of the initial sample size and the covariance function are not critical. The choice of the method, however, can result in significant differences in the performance. In particular, the three most intuitive criteria are found as poor alternatives. Although no criterion is found consistently more efficient than the others, two specialized methods appear more robust on average. 相似文献
64.
Fabrice Rousselle Petrik Clarberg Luc Leblanc Victor Ostromoukhov Pierre Poulin 《The Visual computer》2008,24(7-9):465-474
We present an efficient method for importance sampling the product of multiple functions. Our algorithm computes a quick approximation of the product on the fly, based on hierarchical representations of the local maxima and averages of the individual terms. Samples are generated by exploiting the hierarchical properties of many low-discrepancy sequences, and thresholded against the estimated product. We evaluate direct illumination by sampling the triple product of environment map lighting, surface reflectance, and a visibility function estimated per pixel. Our results show considerable noise reduction compared to existing state-of-the-art methods using only the product of lighting and BRDF. 相似文献
65.
This paper studies connectivity aspects that arise in image operators that process connected components. The focus is on morphological
image analysis (i.e., on increasing image operators) and, in particular, on a robustness property satisfied by certain morphological
filters that is denominated the strong property. The behavior of alternated compositions of openings and closings is investigated
under certain assumptions, particularly connectedness and a connected component preserving condition. It is shown that these
conditions cannot in general guarantee the strong property of certain connected alternated filters because of issues related
to the locality of the filters. As treated in the paper, there have been a series of misunderstandings in the literature concerning
this topic, and it is important to clarify them. The root cause of those problems is discussed, and a solution is indicated.
The class of connected openings and closings used to build connected alternated filters should therefore be defined to avoid
such situations, since the strong property of alternated filters should be a distinctive characteristic of this class.
相似文献
Victor MaojoEmail: |
66.
Continuity versus Discretization 总被引:1,自引:1,他引:0
The threefold interest in architecture, biology and mathematics motivated us to examine and justify new architectural forms.
We discuss some notions of rhythm: Euclidean, morphogenetic and morphologic. Contemporary relationships between structure
and form are based on the generation of shape by technological processes, thus the resulting objects are restricted to their
material expression. Here a phenomenological organisation of form and its continuity with the landscape arise out of the mathematical
and architectural creativity. The use of the computer is applied from outside to inside instead from inside to outside; this
means that we are dealing with the organisational processes via continuous methods instead of evolutionary processes given
by computer simulations, known as genetic algorithms, where the resulting configurations are reduced to a matter of routine. The role of design as an aesthetic component innovates
the theoretical framework of structural engineering to establish the architectural environments. 相似文献
67.
Spatial correlations define the statistical structure of any visual image. Two-point correlations inform the visual system about the spatial frequency content of an image. Higher-order correlations can capture salient features such as object contours. We studied "isodipole" texture discrimination in V1 to determine if higher-order spatial correlations can be extracted by early stages of cortical processing. We made epicortical, local field potential, and single-cell recordings of responses elicited by isodipole texture interchange in anesthetized monkeys. Our studies demonstrate that single neurons in V1 can signal the presence of higher-order spatial correlations in visual textures. This places a computational mechanism, which may be essential for form vision at the earliest stage of cortical processing. 相似文献
68.
Jibo Qin Yibo Dou Jianchi Zhou Victor M. Candelario Henrik Rasmus Andersen Claus Hélix-Nielsen Wenjing Zhang 《Advanced functional materials》2023,33(28):2214839
The conversion of waste plastic into high-value-added chemicals is regarded as a promising approach for relieving global plastic pollution and contributing to the circular economy. Herein, a partial calcination strategy is developed to fabricate a zinc oxide/UiO66-NH2 (ZnO/UiO66-NH2) heterojunction, in which ZnO is encapsulated in porous UiO66-NH2 for the photocatalytic valorization of plastic. This strategy preserves the framework structure of UiO66-NH2, thus enabling the formation of ZnO with ultra-small size distributed inside the skeleton. The synergistic effect of the obtained ZnO/UiO66-NH2 heterojunction facilitates providing an efficient channel for carrier/mass transfer and guarantees structural stability. As a result, ZnO/UiO66-NH2 exhibits high activity for converting polylactic acid (PLA) and polyvinyl chloride (PVC) into acetic acid, coupled with H2 production. This work provides a feasible strategy for rationally designing heterojunction photocatalysts, as well as an insight into understanding the process of photocatalytic valorization of plastic. 相似文献
69.
Composite Materials Based on Shape‐Memory Ti2NiCu Alloy for Frontier Micro‐ and Nanomechanical Applications 下载免费PDF全文
70.
Localized Synthesis of Iron Oxide Nanowires and Fabrication of High Performance Nanosensors Based on a Single Fe2O3 Nanowire 下载免费PDF全文
Oleg Lupan Vasile Postica Niklas Wolff Oleksandr Polonskyi Viola Duppel Victor Kaidas Eugen Lazari Nicolai Ababii Franz Faupel Lorenz Kienle Rainer Adelung 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(16)
A composed morphology of iron oxide microstructures covered with very thin nanowires (NWs) with diameter of 15–50 nm has been presented. By oxidizing metallic Fe microparticles at 255 °C for 12 and 24 h, dense iron oxide NW networks bridging prepatterned Au/Cr pads are obtained. X‐ray photoelectron spectroscopy studies reveal formation of α‐Fe2O3 and Fe3O4 on the surface and it is confirmed by detailed high‐resolution transmission electron microscopy and selected area electron diffraction (SAED) investigations that NWs are single phase α‐Fe2O3 and some domains of single phase Fe3O4. Localized synthesis of such nano‐ and microparticles directly on sensor platform/structure at 255 °C for 24 h and reoxidation at 650 °C for 0.2–2 h, yield in highly performance and reliable detection of acetone vapor with fast response and recovery times. First nanosensors on a single α‐Fe2O3 nanowire are fabricated and studied showing excellent performances and an increase in acetone response by decrease of their diameter was developed. The facile technological approach enables this nanomaterial as candidate for a range of applications in the field of nanoelectronics such as nanosensors and biomedicine devices, especially for breath analysis in the treatment of diabetes patients. 相似文献