检索结果-南通市图书馆

A review of dielectric optical metasurfaces for spatial differentiation and edge detection

Frontiers of Optoelectronics 2021年第2期14卷 187-200页

作者： Lei WAN Danping PAN Tianhua FENG Weiping LIU alexander a.potapov Department of Electronic Engineering College of Information Science and TechnologyJinan UniversityGuangzhou 510632China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China JNU-IREE RAS Joint Laboratory of Information Techniques and Fractal Signal Processing Jinan UniversityGuangzhou 510632China Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes Jinan UniversityGuangzhou 510632China Institute of Radio Engineering and Electronics Russian Academy of SciencesMoscow 125009Russia

Dielectric metasurfaces-based planar optical spatial differentiator and edge detection have recently been proposed to play an important role in the parallel and fast image processing *** the development of dielectric metasurfaces of different geometries and resonance mechanisms,diverse on-chip spatial differentiators have been proposed by tailoring the dispersion characteristics of subwavelength *** review focuses on the basic principles and characteristic parameters of dielectric metasurfaces as first-and second-order spatial differentiators realized via the Green's function *** spatial bandwidth and polarization dependence are emphasized as key properties by comparing the optical transfer flinctions of metasurfaces for different incident wavevectors and *** present the operational capabilities of a two-dimensional spatial differentiator in image information acquisition,edge detection is described to illustrate the practicability of the *** an application example,experimental demonstrations of edge detection for different biological cells and a flower mold are discussed,in which a spatial differentiator and objective lens or camera are integrated in three optical pathway *** realization of spatial differentiators and edge detection with dielectric metasurfaces provides new opportunities for ultrafast information identification in biological imaging and machine vision.

关键词： dielectric metasurfaces spatial differentiator edge detection optical transfer function

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Laplace metasurfaces for optical analog computing based on quasi-bound states in the continuum

引用

Photonics Research 2021年第9期9卷 1758-1766页

作者： DANPING PAN LEI WAN MIN OUYANG WEI ZHANG alexander a.potapov WEIPING LIU ZIXIAN LIANG TIANHUA FENG ZHAOHUI LI Department of Electronic Engineering College of Information Science and TechnologyJinan UniversityGuangzhou 510632China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Institute of Microscale Optoelectronics Shenzhen UniversityShenzhen 518060China State Key Laboratory of Optoelectronic Materials and Technologies and School of Electronics and Information Technology Sun Yat-sen UniversityGuangzhou 511400China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519000China

Laplace operation,the isotropic second-order differentiation,on spatial functions is an essential mathematical calculation in most physical equations and signal *** the Laplace operation in a manner of optical analog computing has recently attracted attention,but a compact device with a high spatial resolution is still ***,we introduce a Laplace metasurface that can perform the Laplace operation for incident lightfield *** exciting the quasi-bound state in the continuum,an optical transfer function for nearly perfect isotropic second-order differentiation has been obtained with a spatial resolution of wavelength *** a Laplace metasurface has been numerically validated with both 1D and 2D spatial functions,and the results agree well with that of the ideal Laplace *** addition,the edge detection of a concerned object in an image has been demonstrated with the Laplace *** results pave the way to the applications of metasurfaces in optical analog computing and image processing.

关键词： surface quasi continuum

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Clipping versus coiling in posterior circulation intracranial aneurysms: a meta-analysis

引用

Chinese Neurosurgical Journal 2019年第3期5卷 151-162页

作者： Eleni Tsianaka Abdullah Al-Shawish alexander potapov Kostas Fountas Michael Spyrou Nikolay Konovalov Department of Neurosurgery University Hospital of LarissaViopolis41111LarissaGreece Department of Neurosurgery Ibn Sina HospitalSabahMedical AreaShuwaikhKuwait Department of Neurotraumatology “N.N.Burdenko”Neurosurgery Institute164th Tverskaya–Yamskaya Str.MoscowRussia Department of Neurosurgery Ygeia Private HospitalGolgon333025LimassolCyprus Department of Spine Neurosurgery “N.N.Burdenko”Neurosurgery Institute164th Tverskaya–Yamskaya Str.MoscowRussia.

Posterior circulation intracranial aneurysm (IA) treatment remains challenging, due to the anatomy of the area and the high rupture possibility. Endovascular treatment seems to be more suitable for these aneurysms, but studies focused on endovascular treatment demonstrate a high rate of re-intervention needing. A meta-analysis might offer a clearer view, being useful in a more effective treatment planning. Methods: A systematic search was performed, using the PubMed database platform. The final article pool contained 20 articles. Studied parameters were operative mortality, late mortality, permanent neurologic deficit (PND), and the need for re-intervention (Re-int). We divided patients into two subgroups, those with ruptured and those with unruptured aneurysm. Statistical analysis was performed using appropriate software. Results: In the total population (645 patients), there was a superiority of coiling over clipping in terms of PND and of coiling in terms of Re-int. As regards mortality, there was no clear superiority of one method over the other. Conclusions: The current study came to the conclusion that there is a superiority of coiling over clipping in terms of PND. On the other hand, clipping seems to be superior to coiling in terms of the need for re-intervention. As regards mortality (both operative and late), there is no clear superiority of one method over the other. Studying subgroups of patients (ruptured and unruptured posterior circulation IAs), in terms of PND, there is no superiority of one method over the other. The same goes for Op-Mo on ruptured aneurysms.

关键词： Clipping Coiling Intracranial aneurysms Meta-analysis Posterior circulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Was Polchinski Wrong? Colombeau Distributional Rindler Space-Time with Distributional Levi-CivitàConnection Induced Vacuum Dominance. Unruh Effect Revisited

引用

Journal of High Energy Physics, Gravitation and Cosmology 2018年第2期4卷 361-440页

作者： Jaykov Foukzon alexander potapov Elena Men’kova Center for Mathematical Sciences Israel Institute of Technology Haifa Israel IRE RAS Moscow Russia All-Russian Research Institute for Optical and Physical Measurements Moscow Russia

The vacuum energy density of free scalar quantum field in a Rindler distributional space-time with distributional Levi-Cività connection is considered. It has been widely believed that, except in very extreme situations, the influence of acceleration on quantum fields should amount to just small, sub-dominant contributions. Here we argue that this belief is wrong by showing that in a Rindler distributional background space-time with distributional Levi-Cività connection the vacuum energy of free quantum fields is forced, by the very same background distributional space-time such a Rindler distributional background space-time, to become dominant over any classical energy density component. This semiclassical gravity effect finds its roots in the singular behavior of quantum fields on a Rindler distributional space-times with distributional Levi-Cività connection. In particular we obtain that the vacuum fluctuations have a singular behavior at a Rindler horizon . Therefore sufficiently strongly accelerated observer burns up near the Rindler horizon. Thus Polchinski’s account doesn’t violate the Einstein equivalence principle.

关键词： Vacuum Energy Density Rindler Distributional Space-Time Levi-Cività Connection Semiclassical Gravity Effect Einstein Equivalence Principle Space-Time Einstein Equivalence Principle

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Solution Cosmological Constant Problem

引用

Journal of Modern Physics 2019年第7期10卷 729-794页

作者： Jaykov Foukzon Elena Men’kova alexander potapov Department of Mathematics Israel Institute of Technology Haifa Israel All-Russian Research Institute for Optical and Physical Measurement Moscow Russia Kotel’nikov Institute of Radioengineering and Electronics Russian Academy of Sciences Moscow Russia

The cosmological constant problem arises because the magnitude of vacuum energy density predicted by the Quantum Field Theory is about 120 orders of magnitude larger then the value implied by cosmological observations of accelerating cosmic expansion. We pointed out that the fractal nature of the quantum space-time with negative Hausdorff-Colombeau dimensions can resolve this tension. The canonical Quantum Field Theory is widely believed to break down at some fundamental high-energy cutoff and therefore the quantum fluctuations in the vacuum can be treated classically seriously only up to this high-energy cutoff. In this paper we argue that the Quantum Field Theory in fractal space-time with negative Hausdorff-Colombeau dimensions gives high-energy cutoff on natural way. We argue that there exists hidden physical mechanism which cancels divergences in canonical QED4, QCD4, Higher-Derivative-Quantum gravity, etc. In fact we argue that corresponding supermassive Pauli-Villars ghost fields really exist. It means that there exists the ghost-driven acceleration of the universe hidden in cosmological constant. In order to obtain the desired physical result we apply the canonical Pauli-Villars regularization up to Λ*. This would fit in the observed value of the dark energy needed to explain the accelerated expansion of the universe if we choose highly symmetric masses distribution between standard matter and ghost matter below the scale Λ*, i.e., The small value of the cosmological constant is explained by tiny violation of the symmetry between standard matter and ghost matter. Dark matter nature is also explained using a common origin of the dark energy and dark matter phenomena.

关键词： Cosmological Constant Problem Quantum Field Theory Vacuum Energy Density Quantum Space-Time Hausdorff-Colombeau Dimension Quantum Fluctuations High-Energy Cutoff Canonical Pauli-Villars Regularization Universe

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Electrodynamics in Noninertial Reference Frames

引用

Journal of Applied Mathematics and Physics 2016年第4期4卷 806-843页

作者： Stanislav A. Podosenov Jaykov Foukzon alexander potapov Elena Men’kova All-Russian Research Institute for Optical and Physical Measurements Moscow Russia Center for Mathematical Sciences Israel Institute of Technology Haifa Israel Kotel’nikov Institute of Radioengineering and Electronics Russian Academy of Sciences Moscow Russia

The electrodynamics both in RF with prescribed law of motion and in FR with prescribed structure is considered. Parallel comparison for solutions in “uniformly accelerated” NRF M?ller system and in uniformly accelerated rigid NFR in the space of the constant curvature is carried out. The stationary criterion is formulated. On the basis of this criterion, one of the “eternal physical problems” concerning the field at uniformly accelerated charge motion is considered. The problems of electromagnetic wave spreading, Doppler’s effect and field transformations are discussed.

关键词： Noninertial Reference Frame (NFR) Möller System Space-Time Curvature Anholonomic Transformations Doppler’s Effect Electromagnetic Wave

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：