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The Fourier Transform and Principles of Quantum Mechanics 被引量:2
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作者 Do Tan Si 《Applied Mathematics》 2018年第4期347-354,共8页
From the hypotheses that the position-representation of a physical state is the Fourier transform of its momentum-representation and that the timerepresentation is the inverse Fourier transform of its energy-represent... From the hypotheses that the position-representation of a physical state is the Fourier transform of its momentum-representation and that the timerepresentation is the inverse Fourier transform of its energy-representation, we are able to obtain the Planck relation E = hν , the de Broglie relation p = h /λ , the Dirac fundamental commutation relation, the Schr?dinger equations, the Heisenberg uncertainty principle in quantum mechanics, and the annihilation/creation of a photon from excitation/de-excitation of an atom following Bohr. 展开更多
关键词 Fourier transform of BRA Obtaining DIRAC COMMUTATION Relation and principleS of Quantum Mechanics
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Uncertainty Principle for the Quaternion Linear Canonical Transform in Terms of Covariance 被引量:2
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作者 Yanna Zhang 《Journal of Beijing Institute of Technology》 EI CAS 2021年第3期238-243,共6页
An uncertainty principle(UP),which offers information about a signal and its Fourier transform in the time-frequency plane,is particularly powerful in mathematics,physics and signal processing community.Under the pola... An uncertainty principle(UP),which offers information about a signal and its Fourier transform in the time-frequency plane,is particularly powerful in mathematics,physics and signal processing community.Under the polar coordinate form of quaternion-valued signals,the UP of the two-sided quaternion linear canonical transform(QLCT)is strengthened in terms of covariance.The condition giving rise to the equal relation of the derived result is obtained as well.The novel UP with covariance can be regarded as one in a tighter form related to the QLCT.It states that the product of spreads of a quaternion-valued signal in the spatial domain and the QLCT domain is bounded by a larger lower bound. 展开更多
关键词 uncertainty principle quaternion linear canonical transform quaternion-valued signals COVARIANCE
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Uncertainty Principles for the Generalized Fourier Transform Associated with Spherical Mean Operator
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作者 Hatem Mejjaoli Youssef Othmani 《Analysis in Theory and Applications》 2013年第4期309-332,共24页
The aim of this paper is to establish an extension of qualitative and quantitative uncertainty principles for the Fourier transform connected with the spherical mean operator.
关键词 Generalized Fourier transform Hardy's type theorem Cowling-Price's theorem Beurling's theorem Miyachi's theorem Donoho-Stark's uncertainty principle.
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Heisenberg Uncertainty Principle for n-Dimen-sional Linear Canonical Transforms
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作者 Yonggang Li Chuan Zhang Huafei Sun 《Journal of Beijing Institute of Technology》 EI CAS 2021年第3期249-253,共5页
The uncertainty principle proposed by German physicist Heisenberg in 1927 is a basic principle of quantum mechanics and signal processing.Since linear canonical transformation has been widely used in various fields of... The uncertainty principle proposed by German physicist Heisenberg in 1927 is a basic principle of quantum mechanics and signal processing.Since linear canonical transformation has been widely used in various fields of signal processing recently and Heisenberg uncertainty principle has been endowed with new expressive meaning in linear canonical transforms domain,in this manuscript,an improved Heisenberg uncertainty principle is obtained in linear canonical trans-forms domain. 展开更多
关键词 Heisenberg uncertainty principle linear canonical transforms Pitt inequality
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Possible Martensitic Transformation in Heusler Alloy Pt_2MnSn from First Principles
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作者 冯琳 郭辰辰 +4 位作者 张雪颖 轩海成 王文洪 刘恩克 吴光恒 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第3期97-100,共4页
Using density functional theory calculations, we investigate the tetragonal distortion, electronic structure and magnetic property of Pt2MnSn. The results indicate that, when the volume-conserving tetragonal distortio... Using density functional theory calculations, we investigate the tetragonal distortion, electronic structure and magnetic property of Pt2MnSn. The results indicate that, when the volume-conserving tetragonal distortion occurs, the energy minimum appears at c/a = 0.84, and the energy difference between the minimum and cubic phase is as high as 107 me V/f. u. Thus from the point of view of thermodynamics, martensitie transformation may occur in Pt2MnSn with decreasing the temperature. The electronic structure of its cubic and martensitic phases also approves this. Moreover, both the cubic and tetragonal phases of Pt2MnSn are ferromagnetic structures and their total magnetic moments are 4.26 μB and 4.12 μB, respectively. 展开更多
关键词 PT Possible Martensitic transformation in Heusler Alloy Pt2MnSn from First principles MN SN
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RELATIVE PRINCIPLE COMPONENT AND RELATIVE PRINCIPLE COMPONENT ANALYSIS ALGORITHM 被引量:2
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作者 Wen Chenglin Wang Tianzhen Hu Jing 《Journal of Electronics(China)》 2007年第1期108-111,共4页
In this letter,the new concept of Relative Principle Component (RPC) and method of RPC Analysis (RPCA) are put forward. Meanwhile,the concepts such as Relative Transform (RT),Ro-tundity Scatter (RS) and so on are intr... In this letter,the new concept of Relative Principle Component (RPC) and method of RPC Analysis (RPCA) are put forward. Meanwhile,the concepts such as Relative Transform (RT),Ro-tundity Scatter (RS) and so on are introduced. This new method can overcome some disadvantages of the classical Principle Component Analysis (PCA) when data are rotundity scatter. The RPC selected by RPCA are more representative,and their significance of geometry is more notable,so that the application of the new algorithm will be very extensive. The performance and effectiveness are simply demonstrated by the geometrical interpretation proposed. 展开更多
关键词 Relative principle Component (RPC) Relative transform (RT) Rotundity Scatter (RS)
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STUDY OF THE EQUIVALENT THEOREM OF GENERALIZED VARIATIONAL PRINCIPLES IN ELASTICITY
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作者 张国清 余建星 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第3期347-357,共11页
The relations of all generalized variational principles in elasticity are studied by employing the invariance theorem of field theory. The infinitesimal scale transformation in field theory was employed to investigate... The relations of all generalized variational principles in elasticity are studied by employing the invariance theorem of field theory. The infinitesimal scale transformation in field theory was employed to investigate the equivalent theorem. Among the results found particularly interesting are those related to that all generalized variational principles in elasticity are equal to each other. Also studied result is that only two variables are independent in the functional and the stress-strain relation is the variational constraint condition for all generalized variational principles in elasticity. This work has proven again the conclusion of Prof. Chien Wei-zang. 展开更多
关键词 ELASTICITY generalized variational principle equivalent theorem scale transformation INVARIANCE
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First principles study of post-boron carbide phases with icosahedra broken
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作者 Ming-Wei Chen Zhao Liang +3 位作者 Mei-Ling Liu Uppalapati Pramod Kumar Chao Liu Tong-Xiang Liang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第10期214-221,共8页
Boron carbide (B4C) is a rhombic structure composed of icosahedra and atomic chains, which has an important application in armored materials. The application of B4C under super high pressure without failure is a hot s... Boron carbide (B4C) is a rhombic structure composed of icosahedra and atomic chains, which has an important application in armored materials. The application of B4C under super high pressure without failure is a hot spot of research. Previous studies have unmasked the essential cause of B4C failure, i.e., its structure will change subjected to impact, especially under the non-hydrostatic pressure and shear stress. However, the change of structure has not been clearly understood nor accurately determined. Here in this paper, we propose several B4C polymorphs including B4C high pressure phases with non-icosahedra, which are denoted as post-B4C and their structures are formed due to icosahedra broken and may be obtained through high pressure and high temperature (HPHT). The research of their physical properties indicates that these B4C polymorphs have outstanding mechanical and electrical properties. For instance, aP10, mC10, mP20, and oP10-B4C are conductive superhard materials. We hope that our research will enrich the cognition of high pressure structural deformation of B4C and broaden the application scope of B4C. 展开更多
关键词 boron carbide structural transformation icosahedra broken physical properties first principles
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Special Relativity with a Preferred Frame and the Relativity Principle
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作者 Georgy I. Burde 《Journal of Modern Physics》 2018年第8期1591-1616,共26页
The purpose of the present study is to develop a counterpart of the special relativity theory that is consistent with the existence of a preferred frame but, like the standard relativity theory, is based on the relati... The purpose of the present study is to develop a counterpart of the special relativity theory that is consistent with the existence of a preferred frame but, like the standard relativity theory, is based on the relativity principle and the universality of the (two-way) speed of light. The synthesis of such seemingly incompatible concepts as the existence of preferred frame and the relativity principle is possible at the expense of the freedom in assigning the one-way speeds of light that exists in special relativity. In the framework developed, a degree of anisotropy of the one-way speed acquires meaning of a characteristic of the really existing anisotropy caused by motion of an inertial frame relative to the preferred frame. The anisotropic special relativity kinematics is developed based on the symmetry principles: 1) Space-time transformations between inertial frames leave the equation of anisotropic light propagation invariant and 2) a set of the transformations possesses a group structure. The Lie group theory apparatus is applied to define groups of transformations between inertial frames. Applying the transformations to the problem of calculating the CMB temperature distribution yields a relation in which the angular dependence coincides with that obtained on the basis of the standard relativity theory but the mean temperature is corrected by the terms second order in the observer velocity. 展开更多
关键词 principle of RELATIVITY Anisotropy of the One-Way Speed of Light LIE GROUPS of transformATIONS CMB
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基于双目视觉的输送带表面损伤定量分析方法
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作者 李杰 王卫红 《天津工业大学学报》 CAS 北大核心 2024年第4期60-66,共7页
为了对输送带表面损伤进行定量分析以有效判断其损伤程度,并根据损伤程度选择检修方法和时间,为工作人员检修提供依据,提出了一种基于双目立体视觉的输送带表面损伤定量分析方法。该方法首先对双目相机进行相机标定,对输送带表面损伤图... 为了对输送带表面损伤进行定量分析以有效判断其损伤程度,并根据损伤程度选择检修方法和时间,为工作人员检修提供依据,提出了一种基于双目立体视觉的输送带表面损伤定量分析方法。该方法首先对双目相机进行相机标定,对输送带表面损伤图像进行图像处理校正、立体匹配,基于视差原理根据三角测量原理获取目标点的三维空间信息,通过数学计算模型对损伤程度进行定量分析,提出了改进的Census变换和SGM(semi-global matching)算法相结合的立体匹配算法。结果表明:提出的改进算法匹配效果有所提升,和Census变换算法及梯度算法进行对比,误匹配率分别降低了5.26百分点和3.92百分点,得出的视差图精度最高;通过提出的方法对输送带表面损伤进行定量分析,在输送带损伤长度、宽度、深度三者误差中,损伤深度误差最大为8.5%,仍在可接受范围。 展开更多
关键词 输送带表面损伤 定量分析 双目立体视觉 Census变换 SGM算法 立体匹配 三角测量原理
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基于傅里叶变换的不确定性原理
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作者 于海燕 郑神州 《大学物理》 2024年第1期1-4,共4页
以波函数的规范化模平方积分作为概率密度函数,我们给出了在L 2意义下的位移函数与速度函数的方差乘积有正下界的海森伯不等式;并用傅里叶变换的微分性质、Plancherel等式以及Cauchy-Schwarz不等式作了证明.另外,Hardy不确定性原理表明... 以波函数的规范化模平方积分作为概率密度函数,我们给出了在L 2意义下的位移函数与速度函数的方差乘积有正下界的海森伯不等式;并用傅里叶变换的微分性质、Plancherel等式以及Cauchy-Schwarz不等式作了证明.另外,Hardy不确定性原理表明可积函数和它的傅里叶变换不能同时迅速衰减,其最优的衰减方式是取高斯函数形式达到等式;基于Phragmen-Lindelof定理(无界区域上的最大模原理),给出了Hardy不确定性的复分析方法证明;最后我们给出了推广的Morgan不等式和Beurling不确定性. 展开更多
关键词 傅里叶变换 海森伯不确定性 Hardy不确定性 Morgan不等式 Beurling不确定性
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基于能量系数的电力变压器热故障严重性评估方法 被引量:2
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作者 范慧芳 咸日常 +3 位作者 刘兴华 张冰倩 陈蕾 高鸿鹏 《电测与仪表》 北大核心 2024年第2期83-88,共6页
运行电力变压器内部的热点温度直接影响其使用寿命和运行可靠性。为准确评估电力变压器内部过热故障的严重程度,文章借助焓变理论提出一种计算故障能量系数的方法,为故障赋予一定的权值系数;并基于能量系数这一概念,以电力变压器各类不... 运行电力变压器内部的热点温度直接影响其使用寿命和运行可靠性。为准确评估电力变压器内部过热故障的严重程度,文章借助焓变理论提出一种计算故障能量系数的方法,为故障赋予一定的权值系数;并基于能量系数这一概念,以电力变压器各类不同程度的热故障为研究对象,建立其严重程度分级评估基准,此基准是以563组电力变压器热故障油色谱分析数据所计算出的能量系数值作为样本数据,利用最大熵原理得出最符合实际分布的电力变压器热故障能量系数概率分布函数,并求取其分位值Q_(20)、Q_(70)和Q_(95)作为热故障严重程度的分级评估值。经实际算例分析,采用文中所提方法,不仅可以实现对热故障严重程度的量化评估,还可以合理地划分其严重等级,可为检修人员制定和执行维护计划提供参考。 展开更多
关键词 电力变压器 热故障 严重程度 能量系数 最大熵原理
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约束Green函数与非线性地基梁模态分析 被引量:1
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作者 赵翔 王琦 +1 位作者 朱伟东 李映辉 《动力学与控制学报》 2024年第2期77-84,共8页
在生物和医学领域,微机电系统(MEMS)中的微梁结构在植入人体的使用时,由于体内的细胞环境类似于水凝胶,在这种环境下工作,设备和仪器的精度和稳定性很大程度上受到细胞弹性的影响.为了分析此类地基梁的动力学问题,本文建立了非线性基础... 在生物和医学领域,微机电系统(MEMS)中的微梁结构在植入人体的使用时,由于体内的细胞环境类似于水凝胶,在这种环境下工作,设备和仪器的精度和稳定性很大程度上受到细胞弹性的影响.为了分析此类地基梁的动力学问题,本文建立了非线性基础上的梁振动模型,研究了任意位置弹簧和非线性弹簧基础上的梁模态.通过Laplace变换和线性叠加原理,得到了一种约束Green函数,利用数值计算验证方案的有效性,并研究了各种重要物理参数的影响,发现弹簧位置向跨中移动时,模态对称性被打破,弹簧刚度增加,模态阶数改变. 展开更多
关键词 约束Green函数 LAPLACE变换 非线性弹簧基础 模态分析 叠加原理
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Transformation and assessment of Chinese pine pure plantations for soil and water conservation in western Liaoning Province,P. R. China 被引量:1
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作者 曾德慧 姜凤岐 +2 位作者 郭浩 范志平 杜晓军 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第2期127-134,i002,i003,共10页
Western Liaoning Province is characterized by huge areas of lowly-efficient Chinese pine (Pinus tabulaeformis Carr.) pure plantations. How to transform these plantations has become an increasingly significant manageme... Western Liaoning Province is characterized by huge areas of lowly-efficient Chinese pine (Pinus tabulaeformis Carr.) pure plantations. How to transform these plantations has become an increasingly significant management problem. In this study, the authors summarized the approaches, which are based on close-to-nature silvicultural system, to transform the pure pine plantations. Native broadleaved trees were planted in three methods: 1) after strip clearcutting, 2) after patch clearcutting; 3) on the open forestland and the forest edge. The transformation targets and the selection of tree species were expatiated in this paper. The key techniques and their application conditions for each method were analyzed and discussed. Through investigation and contrastive analysis, the assessment was made to the stands transformed by strip method. Results showed that the mixed stands at 16 years after transformation had an obvious layered structure and the species richness of understorey vegetation increased by 23.5%–52.9%. Soil enzyme activities of urease, phosphatase and sucrase increased by 6%–142%, 46%–99% and 31%–200%, respetively. Moreover, the transformed stands could effectively control the occurrence of pine caterpillars in plantations. Consequently the transformations enhanced the function of soil and water conservation. Keywords Pinus tabulaeformis - Monoculture - Transformation - Principles and methods - Assessment CLC number S791.254 - S727.22 Document code A Foundation item: This research was supported by grants from the Chinese Academy of Sciences (KZCX3-SW-418), National Natural Science Foundation of China (30100144), and National Key Technologies R & D Program of China (96-007-01-06).Biography: ZENG De-hui (1965-), male, Ph.D. professor in the Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. ChinaResponsible editor: Zhu Hong 展开更多
关键词 Pinus tabulaeformis MONOCULTURE transformATION principles and methods ASSESSMENT
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破解“科林格里奇困境”:教育数字化转型风险治理的向度、原则与进路 被引量:5
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作者 赵书琪 于洪波 《中国电化教育》 CSSCI 北大核心 2024年第3期53-60,共8页
教育数字化转型的“科林格里奇困境”揭示了数字技术在教育场域应用中普遍存在的潜在风险与治理难题,并以算法决策诱发师生认知坎陷、技治主义导致主体价值僭越、数字孪生加剧教育信任危机为具体表征。为有效规制教育数字化转型风险,治... 教育数字化转型的“科林格里奇困境”揭示了数字技术在教育场域应用中普遍存在的潜在风险与治理难题,并以算法决策诱发师生认知坎陷、技治主义导致主体价值僭越、数字孪生加剧教育信任危机为具体表征。为有效规制教育数字化转型风险,治理方案应将社会价值预设于技术设计之中,以韧性建构、多元共治、数字福祉为价值导向,以安全可靠、共生协同、相称认责为基本原则。基于此,我国教育数字化转型风险治理应遵循“刚性底线”与“柔性边界”相统一的治理逻辑,“人性复归”与“良法善治”相交融的治理理念,“责任规制”与“融通联动”相结合的治理策略。 展开更多
关键词 教育数字化转型 风险治理 向度 原则 进路
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Auto-Bcklund transformation and exact solutions of Wick-type stochastic Burgers equation 被引量:1
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作者 陈彬 《Journal of Southeast University(English Edition)》 EI CAS 2005年第4期513-516,共4页
Burgers equation in random environment is studied. In order to give the exact solutions of random Burgers equation, we only consider the Wick-type stochastic Burgers equation which is the perturbation of the Burgers e... Burgers equation in random environment is studied. In order to give the exact solutions of random Burgers equation, we only consider the Wick-type stochastic Burgers equation which is the perturbation of the Burgers equation with variable coefficients by white noise W(t)=Bt, where Bt is a Brown motion. The auto-Baecklund transformation and stochastic soliton solutions of the Wick-type stochastic Burgers equation are shown by the homogeneous balance and Hermite transform. The generalization of the Wick-type stochastic Burgers equation is also studied. 展开更多
关键词 Wick-type stochastic Burgers equation auto-Baecklund transformation stochastic soliton solution white noise Hermite transform homogeneous balance principle
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智能时代深度学习教学法的核心要义与行动框架 被引量:2
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作者 杨南昌 梁慧芳 《电化教育研究》 CSSCI 北大核心 2024年第5期5-12,共8页
智能时代的教学范式面临从“消费模式”向“生成模式”转型的挑战。促进教学范式成功转型的关键在于深度学习方式的变革,并通过重构深度学习教学法实现“化知识为素养”。在考察国际典型深度学习项目的基础上,归结出深度学习教学法的七... 智能时代的教学范式面临从“消费模式”向“生成模式”转型的挑战。促进教学范式成功转型的关键在于深度学习方式的变革,并通过重构深度学习教学法实现“化知识为素养”。在考察国际典型深度学习项目的基础上,归结出深度学习教学法的七大关键特征以及从理解世界、参与世界到改变世界进阶转换的设计要义,并构建了“课堂—学校”系统联动变革课堂的行动框架。深度学习没有固定模式,而现实教学情境又复杂多元。研究认为,为一线教师提供一种由“核心要义+行动框架”组成的、更具情境指导力量的“解释性教学法框架”,将更有助于他们超越具体教学模式的应用局限,有效推动深度学习的实践落地,并更有可能创建更多富有成效且个性多彩的深度学习课堂。 展开更多
关键词 智能时代 深度学习教学法 范式转型 核心要义 行动框架
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北京某剧院加固改造设计 被引量:1
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作者 豆晓汪 吕猛 《工程质量》 2024年第6期13-17,共5页
以实际工程为例,对原结构进行整体计算分析,发现原结构层间位移角超过规范限值,基础承载力不满足,部分框架柱、框架梁配筋不足,底层柱部分轴压比超限。加固方法有加大基础截面,框架柱加固采用加大截面法和外包钢法及粘贴碳纤维方法,框... 以实际工程为例,对原结构进行整体计算分析,发现原结构层间位移角超过规范限值,基础承载力不满足,部分框架柱、框架梁配筋不足,底层柱部分轴压比超限。加固方法有加大基础截面,框架柱加固采用加大截面法和外包钢法及粘贴碳纤维方法,框架梁加固采用外包钢粘贴碳纤维法,板通过粘贴碳纤维方法进行加固。改造的难点在于增加升降乐池,原结构拆除后新建结构结合钢结构的方案的优势达到功能要求。改造过程遵循了结构检测、鉴定、加固、改造的设计原则和设计思路。加固改造后该结构满足现行规范标准要求,并且体现了经济性、安全性、适用性,可为类似工程的加固改造设计提供参考。 展开更多
关键词 加固方法 改造难点 设计原则 设计思路
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钆、氟掺杂二氧化钒的晶体结构演变行为与相变机理
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作者 曲道宇 栾敬德 +3 位作者 刘文刚 可欣 烟征 陶佳璐 《原子与分子物理学报》 北大核心 2024年第4期159-166,共8页
二氧化钒(VO_(2))是一种热致相变材料,其过高的相变温度制约了其潜在应用.元素掺杂能够使VO2的能带结构、态密度、键长和晶胞体积等晶格参数改变,引起其相变行为的变化.借助Materials Studio软件,基于第一性原理和分子轨道理论研究了钆... 二氧化钒(VO_(2))是一种热致相变材料,其过高的相变温度制约了其潜在应用.元素掺杂能够使VO2的能带结构、态密度、键长和晶胞体积等晶格参数改变,引起其相变行为的变化.借助Materials Studio软件,基于第一性原理和分子轨道理论研究了钆、氟掺杂二氧化钒的晶体结构演变行为与相变机理.结果表明,无论F掺杂于VO_(2)(M型)中间O的位置还是两侧O位置,都会引起O-O键收缩,V-V键增长,β角增大,体系亥姆霍自由能增加,带隙相对减小,F侧位掺杂效果最好,随着V^(4+)-V^(4+)同极结合的减少,在1 at%F掺杂时相变温度达到最低;当Gd以0-1.8 at%掺杂于VO_(2)(M)中V位置时,O-O键和V—V键发生收缩,β角减小,亥姆霍自能增加,带隙减小,Gd 4f态与tⅡ轨道重合,使相变能垒变低,相变温度显著降低.钆、氟两种元素掺杂VO2相变机理更符合Peierls-Mott协同相变. 展开更多
关键词 二氧化钒 元素掺杂 晶体结构演变 第一性原理 密度泛函理论 相变机理
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基于三比值法的变压器油色谱分析
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作者 万前宏 叶开迪 张师 《电气开关》 2024年第3期65-67,共3页
研究变压器的在线监测是一项重要的工作,可及时发现变压器的异常状态并进行故障诊断,在减少人力、财力的消耗的同时,又有效保障了变压器的安全可靠运行。研究了油中气体产生的原理和变压器油的取样过程、脱气过程,基于三比值法分析了变... 研究变压器的在线监测是一项重要的工作,可及时发现变压器的异常状态并进行故障诊断,在减少人力、财力的消耗的同时,又有效保障了变压器的安全可靠运行。研究了油中气体产生的原理和变压器油的取样过程、脱气过程,基于三比值法分析了变压器不同运行状态的油色谱。研究表明,采用三比值法可以有效诊断出变压器故障类型。 展开更多
关键词 变压器 油色谱 故障类型 产气原理
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