搜索到66209篇“ ROTATING“的相关文章
The Whole Theory of This Universe—A Step Forward to Einstein. Part-4: “Concept Map of Rotating Universe”
2024年
The article collectively proposes a revolutionary perspective on the universe, intertwining concepts of time, spatial positioning, and cosmic dynamics. We introduce the idea of a rotating universe centered around Mega Central Energy Pools (MCEPs), where time varies relative to the distance from the universe’s center, potentially enabling time travel. This model challenges conventional notions of time and cosmology, suggesting that black holes and white holes act as cosmic recycling factories. Additionally, this model unveils a novel theory of dark matter, positing photons as its constituents and highlighting their role in energy transfer across the cosmos. Furthermore, the investigation into Venus’s unique day-length-to-year-length ratio unveils a microscopic mechanism involving swirling energy droplets, charged particles, and field interactions, offering insights into planetary dynamics on both micro and macro scales.
Rehana Kousar
基于旋转粒化的逻辑回归算法
2024年
逻辑回归(LR)作为监督学习的二元分类广义线性分类器,在处理线性数据方面表现出结构简单、解释性强,拟合效果好的特点。然而,当面对高维、不确定性和线性不可分数据时,逻辑回归的分类效果受到限制。针对逻辑回归的固有缺陷,引入粒计算理论,借助粒化的优势提出一种新型的逻辑回归模型:旋转粒逻辑回归。通过引入旋转粒化理论,在特征两两组合形成的平面坐标系上旋转不同角度,构建旋转粒子,多平面坐标系上粒化构造旋转粒向量。进一步定义粒的大小、度量和运算规则,提出旋转粒逻辑回归的损失函数。通过求解损失函数,得到旋转粒逻辑回归的优化解。最后,采用多个UCI数据集进行实验,从多个评价指标比较的结果表明旋转粒逻辑回归模型的有效性。
孔丽茹陈玉明傅兴宇江海亮许进程
关键词:逻辑回归粒计算损失函数
Exploring the shadow of a rotating charged ModMax black hole
2024年
The research presented in this paper discusses the impact that the parameters of charge(Q)and screening factor(γ)have on properties of the horizon and silhouette of rotating charged Mod Max black holes which were reviewed in[Eur.Phys.J.C(2022)82:1155]recently,building upon previous findings in the field.Furthermore,the study explores the behavior of null geodesics,which can help us better understand the apparent shape of the black hole’s silhouette,as well as the distortion parameter and approximate radii of the silhouette that are influenced by the aforementioned parameters,and there are some values of parameter Q which corresponds to data from the Event Horizon Telescope(EHT).Notably,we explore the distortion parameter and approximate radii of the silhouette,revealing that while an increase inγleads to a growth in silhouette radius(Rs),it simultaneously reduces the distortion rate(δs).Conversely,heightened Q charge results in a reduction of Rsaccompanied by an increase inδs.Lastly,the paper analyzes the effects of the black hole’s parameters on the effective potential and energy emission:the peak value of the energy emission rate experiences a decrease as the screening factor(γ)increases,while it increases with higher values of the charge parameter(Q).
Khurshid KarshiboevFarruh AtamurotovAhmadjon AbdujabbarovAli ÖvgünAnvar Reyimberganov
Preliminary analyses of the dynamics and thermodynamics of rotating regular black holes
2024年
We investigate the dynamic and thermodynamic laws governing rotating regular black holes.By analyzing dynamic properties,i.e.,the interaction between scalar particles and rotating regular black holes,we establish the criteria that determine whether such black holes satisfy the laws of thermodynamics.In addition,we provide the general form of conserved quantities related to rotating regular black holes,including the relevant flows associated with neutral scalar particles.Meanwhile,we reexamine the relationship between the third law of thermodynamics and weak cosmic censorship conjecture for rotating regular black holes.Based on the abovementioned criteria,we discuss the laws of thermodynamics for three models of rotating regular black holes:Rotating Hayward black holes,Kerr black-bounce solutions,and loop quantum gravity black holes.Our findings indicate that none of the three models satisfies the first law of thermodynamics.In particular,the first and third models fail to comply with the three laws of thermodynamics,whereas the second model satisfies only the second and third laws of thermodynamics.Finally,we attempt to rescue the laws of thermodynamics by modifying entropy or extending the phase space.However,the two scenarios cannot ensure the three laws of thermodynamics in the three models,which reveals an unusual property of rotating regular black holes.
杨昊余长江缪炎刚
自复位转动摩擦阻尼器弯矩-转角恢复力性能研究
2024年
为了满足减震结构对可恢复功能的要求,针对传统摩擦阻尼器不具备自复位能力震后存在较大残余变形的问题,提出了一种基于形状记忆合金的自复位转动摩擦阻尼器,由摩擦耗能装置和形状记忆合金自复位装置组合而成。介绍了该SCRF(self-centering rotating friction)阻尼器的构造形式、工作原理,通过理论推导建立了SCRF阻尼器的弯矩-转角恢复力模型,通过ABAQUS软件有限元数值分析结果对弯矩-转角恢复力模型进行了验证,分析了低周往复荷载作用下SCRF阻尼器的滞回性能,并进行了参数分析。结果表明:有限元计算结果与阻尼器恢复力模型结果吻合良好;提高接触面间的摩擦因数与斜面高度可以提高阻尼器的最大承载力、耗能能力、有效刚度,但是超过一定限值的斜面高度会降低阻尼器的自复位能力;施加SMA螺栓预紧力可以提高阻尼器的摩擦启动弯矩,对于阻尼器的耗能能力与最大承载力影响不大。
史庆轩王朴臻戎翀王朋王斌
对转螺旋桨气动力和气动噪声风洞试验技术
2024年
针对对转螺旋桨气动力和气动噪声性能评估和优化研究需求,依托声学风洞,研发了1套大功率对转螺旋桨动力模拟试验装置,并发展了对转螺旋桨气动力和气动噪声风洞试验数据处理方法。对转螺旋桨动力模拟试验装置由300 kW电动机提供动力输入,由齿轮箱实现增速和内外传动轴反向旋转,由旋转轴天平测量气动力。装置完成研制后,在5.5 m×4 m声学风洞开展了对转螺旋桨气动力和气动噪声试验。结果表明对转螺旋桨动力模拟试验装置的转速控制精度优于0.5 r/min,传动效率达到97.7%,装置运行平稳、可靠;对转螺旋桨试验的拉力系数重复性精度优于0.002 1,功率系数重复性精度优于0.002 2,气动噪声重复性精度优于0.5 dB。
陈正武姜裕标赵昱卢翔宇仝帆
关键词:对转螺旋桨气动噪声声学风洞
Observational signatures of rotating black holes in the semiclassical gravity with trace anomaly
2024年
In a recent work by Fernandes[Phys.Rev.D 108(6),L061502(2023)],an exact stationary and axisymmetric solution was discovered in semiclassical gravity with type-A trace anomaly.This was identified as a quantum-corrected version of the Kerr black hole.In this study,we explore the observational signatures of this black hole solution.Our investigation reveals that prograde and retrograde light rings exist,whose radii increase monotonically with the coupling parameterα.Whenαis negative,the shadow area for the quantum-corrected black hole is smaller than that of the Kerr black hole,whereas whenαis positive,the area is larger.For a near-extremal black hole,its high-spin feature(the NHEKline)is found to be highly susceptible to disruption byα.Furthermore,we discuss the images of the quantum-corrected black hole in the presence of a thin accretion disk and compare them to those of the Kerr black hole.Our study highlights the importance of near-horizon emission sources in detecting the effects of quantum corrections by black hole images.
Zhenyu ZhangYehui HouMinyong Guo
Dynamics of a rotating ring-stiffened sandwich conical shell with an auxetic honeycomb core
2024年
The free vibration analysis of a rotating sandwich conical shell with a reentrant auxetic honeycomb core and homogenous isotropic face layers reinforced with a ring support is studied.The shell is modeled utilizing the first-order shear deformation theory(FSDT)incorporating the relative,centripetal,and Coriolis accelerations alongside the initial hoop tension created by the rotation.The governing equations,compatibility conditions,and boundary conditions are attained using Hamilton’s principle.Utilizing trigonometric functions,an analytical solution is derived in the circumferential direction,and a numerical one is presented in the meridional direction via the differential quadrature method(DQM).The effects of various factors on the critical rotational speeds and forward and backward frequencies of the shell are studied.The present work is the first theoretical work regarding the dynamic analysis of a rotating sandwich conical shell with an auxetic honeycomb core strengthened with a ring support.
S.JAHANGIRIA.GHORBANPOUR ARANIZ.KHODDAMI MARAGHI
超宽超重曲线高架桥转体施工关键力学性能分析
2024年
以西北地区某桥面单幅宽36.5 m、重近20000 t曲线T构梁转体施工为研究对象,通过建立有限元模型,分析在大温差条件下桥梁上部结构变形情况、承台受力情况、承台温度效应,并对施工安全风险进行合理评估。研究表明:上、下球铰圆形接触面端部较大的水平压力会导致球铰部分区域出现主拉应力,设计时需增大球铰半径或降低球铰高度以减小或消除拉应力;转动球铰对悬臂梁变形有较大影响,将不平衡重量控制在0.8%以内时,可较好降低转动球铰对悬臂梁变形的影响;温度应力引起的承台最大拉应力值满足规范限值要求。
王土
关键词:转体施工大温差
具有内阻的旋转锥形复合材料刀杆铣削过程稳定性的仿真分析
2024年
研究考虑材料内阻的旋转圆锥形复合材料刀杆铣削系统的再生颤振稳定性。基于复合材料粘弹性本构关系、Hamilton原理和Rayleigh梁理论,结合再生时滞铣削力模型,分别导出旋转坐标以及惯性坐标表示的颤振偏微分方程。采用Galerkin法对颤振偏微分方程进行离散化。基于自由振动分析和能量法计算复合材料刀杆的模态损耗因子;基于特征值分析技术计算旋转复合材料刀杆的临界速度和失稳阈。采用时域半离散法和频域零阶近似解法,预测切削系统的稳定性。分析锥度比、长径比、铺层角、铺层方式,以及内、外阻对切削稳定性的影响。计算结果表明,轴对称旋转刀杆铣削过程在两种坐标系下的稳定性预测结果是一致的。研究发现,在高转速下,由于旋转复合材料刀杆内阻的作用,切削系统出现新的不稳定区域。这些新的不稳定区域的起始转速等于旋转复合材料刀杆的失稳阈。
任勇生张玉环张金峰
关键词:铣削颤振

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侯英
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供职机构:清华大学
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纪升伟
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供职机构:昆明理工大学
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高娟
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研究主题:OECD国家 高职教育 经济合作与发展组织 影响因素 KANO模型
陈次星
作品数:13被引量:5H指数:1
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梁宝社
作品数:14被引量:18H指数:3
供职机构:河北建筑科技学院数理系
研究主题:格点 相干结构 剪切流 自相关 COUETTE