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New black-to-white hole solutions with improved geometry and energy conditions

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 30-43页

作者： Zhongwen Feng Yi Ling Xiaoning Wu Qingquan Jiang School of Physics and Astronomy China West Normal UniversityNanchong 637009China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics University of Chinese Academy of SciencesBeijing 100049China Institute of Mathematics Academy of Mathematics and System Science and Hua Loo-Keng Key Laboratory of MathematicsChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100190China

We construct new black-to-white hole solutions which connect the geometry of spacetime at some gluing surface inside the horizon.The continuity of the metric can be guaranteed up to the arbitrary order which is controlled by the power factor n.This sort of black-to-white holes is characterized by the sub-Planckian scalar curvature,independent of the mass of black-to-white holes.More importantly,we show that the energy condition is only violated within a small region near the gluing surface.The geodesics of particles within the region from black hole to white hole is also analyzed.It turns out that the matter falling into the black hole may pass through the center without singularity and come out from the white hole.This scenario provides novel ideas for understanding the information loss paradox in traditional black hole physics.

关键词： regular black hole energy condition singularity quantum gravity

Three-dimensional nanoscale vortex line visualization and chiral nanostructure fabrication of tightly focused multi-vortex beams via direct laser writing

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Photonics Research 2024年第1期12卷 70-77页

作者： MENGDI LUO JISEN WEN PENGCHENG MA QIUYUAN SUN XIANMENG XIA GANGYAO ZHAN ZHENYAO YANG LIANG XU DAZHAO ZHU CUIFANG KUANG XU LIU Research Center for Intelligent Chips and Devices Zhejiang LabHangzhou 311100China State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and EngineeringZhejiang UniversityHangzhou 310027China ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311200China

Optical singularity is pivotal in nature and has attracted wide interest from many disciplines nowadays,including optical communication,quantum optics,and biomedical imaging.Visualizing vortex lines formed by phase singularities and fabricating chiral nanostructures using the evolution of vortex lines are of great significance.In this paper,we introduce a promising method based on two-photon polymerization direct laser writing(2PP-DLW)to record the morphology of vortex lines generated by tightly focused multi-vortex beams(MVBs)at the nanoscale.Due to Gouy phase,the singularities of the MVBs rotate around the optical axis and move towards each other when approaching the focal plane.The propagation dynamics of vortex lines are recorded by 2PP-DLW,which explicitly exhibits the evolution of the phase singularities.Additionally,the MVBs are employed to fabricate stable three-dimensional chiral nanostructures due to the spiral-forward property of the vortex line.Because of the obvious chiral features of the manufactured nanostructures,a strong vortical dichroism is observed when excited by the light carrying orbital angular momentum.A number of applications can be envisioned with these chiral nanostructures,such as optical sensing,chiral separation,and information storage.

关键词： vortex chiral singularity

基于singularity的超算资源容器化

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信息技术与信息化 2024年第6期 120-126页

作者：王祥凯山东正云信息科技有限公司山东济南250098

深度学习往往伴随着大量的计算,属于典型的高性能计算(HPC)应用。基于Python的深度学习中往往使用PyTorch或者TensorFlow库,环境的配置与管理极为复杂,可重复性低,导致代码的升级、管理、测试、迁移成为大难题。为此,诞生了容器化技术... 详细信息

深度学习往往伴随着大量的计算,属于典型的高性能计算(HPC)应用。基于Python的深度学习中往往使用PyTorch或者TensorFlow库,环境的配置与管理极为复杂,可重复性低,导致代码的升级、管理、测试、迁移成为大难题。为此,诞生了容器化技术。容器化技术以Docker为代表,通过在迁移代码的同时迁移代码运行环境,从而避免了代码在移植的时候存在繁杂的环境配置过程。但是超算服务器与普通的服务器又有很大的差别,如开发人员无root权限,测试代码时需要进行资源管理(内存,CPU)。这些问题都让Docker技术在HPC环境的应用受限,针对以上问题,使用singularity代替Docker,在神威蓝光II型超级计算机上尝试生成了Python3.7+Numpy+Pandas+Scipy数据科学计算环境的singularity镜像文件,在阿里云服务器上无root权限创建容器并成功运行了距离判别Python计算程序。结果表明,使用singularity可以解决Docker在服务器上面的root权限问题,有助于深度学习环境在不同HPC服务器上面的部署。

关键词：容器化技术高性能计算(HPC) Docker singularity

Universal Hyperthermal Model for Mass Extinctions

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Journal of Earth Science 2024年第2期35卷 704-707页

作者： Michael J.Benton Paleobiology Research Group School of Earth SciencesUniversity of BristolLife Sciences BuildingTyndall AvenueBristolBS81TQUK

INTRODUCTION Earth scientists have long sought universal features of past extinction crises.It can be argued that each past extinction event was a singularity,caused by combinations of circumstances that are unique in each case,and therefore that the search for common causes is futile.However,a key feature of the uniformitarian approach to geology is that past processes are the same as modern-day processes and,with that in mind,earth scientists are keen to use their knowledge to contribute some understanding to the study of the present and future climate crisis.

关键词： extinction singularity Extinction

Kinematics Analysis and singularity Avoidance of a Parallel Mechanism with Kinematic Redundancy

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Chinese Journal of Mechanical Engineering 2022年第5期35卷 244-261页

作者： Chaoyu Shen Haibo Qu Sheng Guo Xiao Li Robotics Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China China Waterborne Transport Research Institute Beijing 100088China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control TechnologyMinistry of EducationBeijing Jiaotong UniversityBeijing 100044China

The kinematic redundancy is considered as a way to improve the performance of the parallel mechanism.In this paper,the kinematics performance of a three degree-of-freedom parallel mechanism with kinematic redundancy(3-DOF PM-KR)and the influence of redundant parts on the PM-KR are analyzed.Firstly,the kinematics model of the PM-KR is established.The inverse solutions,the Jacobian matrix,and the workspace of the PM-KR are solved.Secondly,the influence of redundancy on the PM-KR is analyzed.Since there exists kinematic redundancy,the PM-KR possesses fault-tolerant performance.By locking one actuating joint or two actuating joints simultaneously,the fault-tolerant workspace is obtained.When the position of the redundant part is changed,the workspace and singularity will be changed.The results show that kinematic redundancy can be used to avoid singularity.Finally,the simulations are performed to prove the theoretical analysis.

关键词： Parallel mechanism Kinematic redundancy singularity Simulation analysis

Gravitation, Density Upper Limit and Quantization of Space

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Journal of High Energy Physics, Gravitation and Cosmology 2024年第2期10卷 534-545页

作者： Doron Kwiat Independent Researcher Mazkeret Batyia Israel

The singularity at distance r → 0 at the center of a spherically symmetric non-rotating, uncharged mass of radius R, is considered here. Under inverse square law force, the Schwarzschild metric, needs to be modified, to include Newton’s Shell Theorem (NST). By including NST for r, both Schwarzschild singularity at r = 2GM/c2 and at r → 0 singularities are removed from the metric. Near R → 0, the question of maximal density is considered based on Schwarzschild’s modified metric, and compared to the quantum limit of maximal mass density put by Planck’s quantum-based universal units. It is asserted, that General relativity, when combined with Planck’s universal units, inevitably leads to quantization of gravity.

关键词： Gravitation Shell Theorem singularity Schwarzschild Radius CGH Physics: Planck’s Scale

The Structure of Gravity Funnels and Stability Considerations of Matter in SI Units

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Journal of High Energy Physics, Gravitation and Cosmology 2024年第1期10卷 71-81页

作者： Tobias Bartusch Bartusch Plasma and Vacuum Kissing Germany

This article describes an extension of the theory of vortices to electromagnetic types with a start point from known fluid systems. From this, properties of gravity-generating objects (particles and black holes) can be derived, which can also describe their possible interior. This also leads to questions about stability, which are then addressed and ultimately lead to considerations of black holes and their possible internal structure. The results fit into the observable areas and can also be directly verified because they were analytically calculated in SI units.

关键词： Black Hole Dark Matter Electromagnetic Gravity singularity Vortex

singularity problem of control moment gyro cluster with vibration isolators

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Chinese Journal of Aeronautics 2016年第1期29卷 238-247页

作者： Cui Yinghui Zheng Gangtie School of Aerospace Tsinghua University

As powerful torque amplification actuators, control moment gyros （CMGs） are often used in the attitude control of many state-of-the-art high resolution satellites. However, the distur- bance generated by the CMGs can not only reduce the attitude stability of a satellite but also dete- riorate the performance of optic payloads. Currently, CMG vibration isolators are widely used to target this problem. The isolators can affect the singularity of the CMG system as they are placed between the CMGs and the satellite bus and provide additional freedoms to the CMG system due to their flexibility. The formulation of the output torque of a CMG is studied first considering the dynamic imbalance of its spin rotor and then the deformation angle as a result of the isolator＇s flex- ibility is calculated. With the additional freedoms, the influence of isolator on the singularity problem is studied and a new steering logic to escape from the singular states is proposed.

关键词： Satellite singularity Steering logic Torque error Vibration isolation

singularity Analsis of Geometric Constraint Systems

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Journal of Computer Science & Technology 2002年第3期17卷 314-323页

作者：彭小波 NationalCADSupportSoftwareEngineeringResearchCenterHauzhongUniversityofScienceandTechnology Wuhan4300

singularity analysis in an important subject of the geometric constraint satisfaction problem.In this paper,three kinds of singularities are described and corresponding identifcation methods are presented for both under0constrained systems and over-constrained systems,Another special but common singularity for under-constrained geometric systems,pseudo-singularity,is analyzed.Pseudo-singularity is caused by a variety of constraint mathching of under-constrained systems and can be removed by improving constraint distribution.To avoid pseudo-singularity and decide redundant constraints adaptively,a differentiaiton algorithm is proposed in the paper.Its corrctness and effciency have been validated through its practical applications in a 2D/3D geometric constraint solver CBA.

关键词： geometric constraint satisfaction parametric design singularity redundant constraint pseudo-singularity