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与图像内容无关的聚焦程度评价方法

西安交通大学学报 2025年第1期59卷 116-124页

作者：夏晓华柴玉琳岳鹏举杨治秦绪芳长安大学道路施工技术与装备教育部重点实验室西安710000

针对现有的聚焦程度评价方法在图像场景内容改变时不能正确评价图像聚焦程度的问题,基于“分类+拟合”的思想,提出了一种与高斯模糊标准差完全等价的图像聚焦程度评价方法。首先,建立了以有限高斯模糊标准差为标记的图像聚焦程度分类数... 详细信息

针对现有的聚焦程度评价方法在图像场景内容改变时不能正确评价图像聚焦程度的问题,基于“分类+拟合”的思想,提出了一种与高斯模糊标准差完全等价的图像聚焦程度评价方法。首先,建立了以有限高斯模糊标准差为标记的图像聚焦程度分类数据集;然后,构建了用于提取图像高斯模糊标准差分类分数的非对称核卷积神经网络(AKC-net);最后,采用三次样条插值函数拟合AKC-net全连接层输出的分类分数以及对应的高斯模糊标准差,以最大分数对应的标准差作为图像的聚焦程度评价结果,并在Waterloo数据集和实际拍摄图像上分别进行仿真实验和实拍实验。结果表明:所提方法在不同聚焦图像上分类的平均准确率可达到97.7%,得到的评价结果与高斯模糊标准差真值的均方根误差和平均绝对误差均小于0.07,且实际拍摄图像的聚焦测度值与图像内容无关,实现了图像聚焦程度的绝对评价。

关键词：聚焦程度评价高斯模糊标准差非对称核卷积神经网络三次样条插值

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Global Optimization of Polynomials over Real Algebraic Sets

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Journal of Systems Science & Complexity 2019年第1期32卷 158-184页

作者： WANG Chu yang zhi-Hong zhi Lihong Beijing Jinghang Computation and Communication Research Institute KLMM Academy of Mathematics and Systems Science Chinese Academy of Sciences University of Chinese Academy of Sciences

Let f, g_1, ···, g_s be polynomials in R[X_1, ···, X_n]. Based on topological properties of generalized critical values, the authors propose a method to compute the global in?mum f~? of f over an arbitrary given real algebraic set V = {x ∈ R^n| g_1(x) = 0, ···, g_s(x) = 0}, where V is not required to be compact or smooth. The authors also generalize this method to solve the problem of optimizing f over a basic closed semi-algebraic set S = {x ∈ R^n| g_1(x) ≥ 0, ···, g_s(x) ≥ 0}.

关键词： Polynomial optimization real algebraic set generalized critical value

On the surface brightness radial profile of the extendedγ-ray sources

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Science China(Physics,Mechanics & Astronomy) 2022年第1期65卷 84-91页

作者： Rui-zhi yang Bing Liu Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Key Labrotory for Research in Galaxies and Cosmology University of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210093China

The morphology of the extendedγ-ray source is governed by the propagation process of parent relativistic *** this paper,we investigate the surface brightness radial profile of extendedγ-ray sources illuminated by cosmic ray protons and electrons,considering the radiation mechanisms,projection effects,and the response of *** find that the parent particle species and the propagation process can cause considerable differences in the observed radial ***,the surface brightness profile can be used as a unique tool to identify the radiation mechanism and the propagation process of the parent *** addition,we also discuss the possible implications regarding the latest discoveries from very/ultra-high energyγ-ray instruments like LHAASO and HAWC.

关键词： cosmic rays γ-ray sources diffuse emission

SiS_(2)/ZnO范德华异质结光催化水分解第一性原理研究

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原子与分子物理学报 2025年第6期42卷 31-36页

作者：李家豪黄欣杨志红南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院南京210023 南京邮电大学理学院南京210023

基于第一性原理方法,研究了SiS_(2)/ZnO范德华异质结的电子结构和光催化性质.结果表明,SiS_(2)/ZnO异质结是带隙值为1.32 eV的半导体材料,表现出交错排列的能带结构.在异质结界面处,形成了从ZnO指向SiS_(2)的内置电场,该内置电场的存在... 详细信息

基于第一性原理方法,研究了SiS_(2)/ZnO范德华异质结的电子结构和光催化性质.结果表明,SiS_(2)/ZnO异质结是带隙值为1.32 eV的半导体材料,表现出交错排列的能带结构.在异质结界面处,形成了从ZnO指向SiS_(2)的内置电场,该内置电场的存在使得SiS_(2)/ZnO异质结中形成了特殊的“Z-型”载流子迁移模式,有利于电子空穴对的有效分离,同时增强了载流子的氧化还原能力.异质结构具有良好的热力学稳定性,且带边位置跨越水的氧化还原电位.与单层材料相比,SiS_(2)/ZnO异质结光吸收谱出现红移现象,表现出更宽的光吸收范围(从可见光到紫外光)及更强的光吸收强度(达到10~5 cm^(-1)量级).另外,通过施加双轴应变,可以有效调控SiS_(2)/ZnO异质结的带隙值.以上结果表明SiS_(2)/ZnO异质结有潜力成为新型光催化剂用于全解水.

关键词： SiS_(2)/ZnO Z-型范德华异质结光催化电子结构第一性原理

应为、难为与可为:新时期乡村教师新乡贤角色承担的多维分析

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黄冈师范学院学报 2025年第1期45卷 76-82页

作者：朱广兵辛治洋马鞍山师范高等专科学校安徽和县238200 安徽师范大学教育科学学院安徽芜湖241000

通过对乡村教师在乡村建设中的历史经验和现代实践进行系统梳理,发现学术界关于乡村教师与乡村社区治理之间关系的探讨主要可归纳为三种视角:乡村教师治村论、治教论以及助村论。在美丽乡村建设的背景下,乡村教师被赋予了新乡贤角色,这... 详细信息

通过对乡村教师在乡村建设中的历史经验和现代实践进行系统梳理,发现学术界关于乡村教师与乡村社区治理之间关系的探讨主要可归纳为三种视角:乡村教师治村论、治教论以及助村论。在美丽乡村建设的背景下,乡村教师被赋予了新乡贤角色,这一角色以乡建精英和文化使者的身份为标志,同时新乡贤角色的扮演亦能促进乡村青年教师的专业成长。然而,在实际工作中,乡村教师在扮演新乡贤角色时遭遇了角色定位模糊、工作负担过重以及能力单一等多重障碍。为促进乡村教师有效实现新乡贤角色的内生型构建,本研究认为需从教育管理的顶层设计、师范教育中的专业培训以及教师履职过程中的主观能动性三个层面着手,提供相应的支持与改进措施。

关键词：乡村教师新乡贤角色乡村振兴乡村文化乡村教育

DISCUSSION ON MECHANISM OF CAVITATION DAMAGE ON SUPER HIGH DAMS

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Journal of Hydrodynamics 2000年第4期12卷 84-87页

作者： yang zhi-ming Wuhan University of Hydraulic and Electric Engineering Wuhan 430072P.R.China

In this short paper the following viewpoints are discussed: it is possible in super high dams that the discharge flow, either in discharge tunnel or in open channel, may be an air water mixtures (two phase flow) in which the sound speed could reduce sharply depending on concentration of air, and the shock wave could be caused somewhere in super high flow while the flow velocity reaches or exceeds the sound speed in it. Besides bubble collapse, the correlation between shock wave and cavitation bubble collapse should be considered as the main mechanism of serious damage on discharge structures of super high dams.

关键词： cavitation damage shock wave super high dam

Wind tunnel simulation of wind loading on a solid structure of revolution

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Acta Mechanica Sinica 2010年第4期26卷 551-558页

作者： Le-Tian yang zhi-Fu Gu State Key Laboratory of Turbulence and Complex Systems and College of Engineering Peking University 100871 Beijing China

The wind tunnel simulations of wind loading on a solid structure of revolution with one smooth and five rough surfaces were conducted using wind tunnel tests. Timemean and fluctuating pressure distributions on the surface were obtained, and the relationships between the roughness Reynolds number and pressure distributions were analyzed and discussed. The results show that increasing the surface roughness can significantly affect the pressure distribution, and the roughness Reynolds numbers play an important role in the change of flow patterns. The three flow patterns of subcritical, critical and supercritical flows can be classified based on the changing patterns of both the mean and the fluctuating pressure distributions. The present study suggests that the wind tunnel results obtained in the supercritical pattern reflect more closely those of full-scale solid structure of revolution at the designed wind speed.

关键词： Wind tunnel simulation Roughness Reynolds number Pressure distribution Solid structure of revolution

Effects of Cinnamic Acid on Bacterial Community Diversity in Rhizosphere Soil of Cucumber Seedlings Under Salt Stress

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Agricultural Sciences in China 2010年第2期9卷 266-274页

作者： LIU Jing WU Feng-zhi yang yang Horticulture College Northeast Agricultural University Harbin 150030 P.R.China

To investigate the effects of a plant autotoxin, cinnamic acid, on bacterial communities in the rhizosphere soil of cucumber seedlings under salt stress, we used cucumber as the experimental material, cinnamic acid as the autotoxin, and NaCl to apply salt stress. Bacterial communities in the rhizosphere soil were analyzed using polymerase chain reaction （PCR）, denaturing gradient gel electrophoresis （DGGE）, and clone sequencing. Salt stress decreased the diversity of bacterial species in rhizosphere soil of cucumber seedlings at several growth stages. Cinnamic acid exacerbated the effects of salt stress at high concentrations, but alleviated its effects at low concentrations. Cloning and sequencing results indicated that DGGE bands amplified from soil samples showed high homology to uncultured bacterial species. Cinnamic acid at 50 mg kg^-1 soil improved cucumber growth and was the most effective treatment to alleviate the effects of salt stress on bacterial communities.

关键词： bacteria cinnamic acid cucumber salt stress PCR-DGGE

Influence of Prior Austenite Deformation and Non-Metallic Inclusions on Ferrite Formation in Low-Carbon Steels

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Journal of Iron and Steel Research International 2010年第6期17卷 36-42页

作者： ZHANG Chi XIA zhi-xin yang zhi-gang LIU zhi-hao Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Effects of prior austenite deformation and non-metallic inclusions on the ferrite nucleation and grain refine- ment of two kinds of low-carbon steels have been studied. The ferrite nucleation on MnS and V（C, N） is observed. The combination of thermomeehanical processes with adequate amounts of non-metallic inclusions formed in low-car- bon steels could effectively refine the grain size and the microstructure. Ferrite nucleated on the single MnS or V（C, N） inclusions and complex MnS＋V（C,N） inclusion. The proper addition of elements S and V could effectively promote the formation of ferrite and further refinement of ferrite grains.

关键词： austenite deformation non-metallic inclusion ferrite nucleation low-carbon steel