检索结果-南通市图书馆

The‘skin effect’of subsurface damage distribution in materials subjected to high-speed machining

在线全文

学校读者我要写书评

暂无评论

International Journal of Extreme Manufacturing 2019年第1期1卷 126-137页

作者： Bi Zhang Jingfei Yin The Southern University of Science and Technology ShenzhenPeople’s Republic of China The University of Connecticut StorrsCTUnited States of America Dalian University of Technology DalianPeople’s Republic of China

This paper proposes the‘skin effect’of the machining-induced damage at high strain *** paper first reviews the published research work on machining-induced damage and then identifies the governing factors that dominate damage formation *** many influential factors,such as stress-strain field,temperature field,material responses to loading and loading rate,and crack initiation and propagation,strain rate is recognized as a dominant factor that can directly lead to the‘skin effect’of material damage in a loading *** paper elucidates that material deformation at high strain rates(>103 s−1)leads to the embrittlement,which in turn contributes to the‘skin effect’of subsurface *** paper discusses the‘skin effect’based on the principles of dislocation kinetics and crack initiation and *** provides guidance to predicting the material deformation and damage at a high strain-rate for applications ranging from the armor protection,quarrying,petroleum drilling,and high-speed machining of engineering materials(*** and SiC reinforced aluminum alloys).

关键词： skin effect strain rate dislocation embrittlement damage

Study on manufacturing freeform surface parts in micro EDM based on skin effect theory

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2011年第4期17卷 439-445页

作者：刘宇 Sundaram Murali Meenakshi Zhao Fuling Rajurkar Kamlakar P Key Laboratory for Precision ＆ Non-traditional Machining Technology of Ministry of Education Dalian University of Technology Dalian 116024 P.R. China School of Dynamic Systems University of Cincirmati Cincinnati OH 45221 USA Center for Nontraditional Manufacturing Research University of Nebraska-Lincoln Lincoln NE 68588 USA

Micro fabrication of freeform surface parts made of hard and brittle materials is always a tough job in micro machining field. This paper tries to fabricate freeform surface feature by using smooth surface of tool electrode after tool wear in micro EDM. According to the skin effect theory, the tool end shape in the stage of uniform wear can be changed by adjusting the frequency of discharge pulse. The electrical energy distributing rule of tool electrode section in RC circuit has been investigated under the influence of skin effect, and the law of spark location change has been summarized. The experimental studies demonstrate that different shapes of tool ends can be achieved by varying the pulse frequencies of discharge power supply. Additionally, a micro part of freeform surface feature with high precision and good surface quality has been successfully obtained by micro EDM through adopting the smooth surface after tool wear.

关键词： micro EDM freeform surface skin effect tool shape

skin effect in a DC Coil of Magnet during Startup Phase

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2001年第2期3卷 679-682页

作者：王龙 Institute of Physics the Chinese Academy of Sciences Beijing 100080 China

An analytic expression of effective resistance in a conductor has been obtained for thin skin layer approximation and a linearly rising current. The result can be used in the design of magnets in nuclear fusion research.

关键词： effective resistance direct current skin effect Thin skin conducting bodies nuclear fusion Coils MAGNETS Linearly

Parity-dependent skin effects and topological properties in the multilayer nonreciprocal Su−Schrieffer−Heeger structures

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第3期19卷 115-133页

作者： Jia-Rui Li Cui Jiang Han Su Di Qi Lian-Lian Zhang Wei-Jiang Gong College of Sciences Northeastern UniversityShenyang 110819China Basic Department Shenyang Institute of EngineeringShenyang 110136China

We concentrate on the skin effects and topological properties in the multilayer non-Hermitian Su−Schrieffer−Heeger (SSH) structure, by taking into account the nonreciprocal couplings between the different sublattices in the unit cells. Following the detailed demonstration of the theoretical method, we find that in this system, the skin effects and topological phase transitions induced by nonreciprocal couplings display the apparent parity effect, following the increase of the layer number of this SSH structure. On the one hand, the skin effect is determined by the parity of the layer number of this SSH system, as well as the parity of the band index of the bulk states. On the other hand, for the topological edge modes, such an interesting parity effect can also be observed clearly. Next, when the parameter disorders are taken into account, the zero-energy edge modes in the odd-layer structures tend to be more robust, whereas the other edge modes are easy to be destroyed. In view of these results, it can be ascertained that the findings in this work promote to understand the influences of nonreciprocal couplings on the skin effects and topological properties in the multilayer SSH lattices.

关键词： multilayer SSH lattice nonreciprocal couplings band structure skin effect

Anomalous time-reversal symmetric non-Hermitian systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第6期33卷 162-166页

作者：易益妃 Sichuan Normal University Chengdu 610066China

The conditions for the emergence of the non-Hermitian skin effect, as a unique physical response of non-Hermitian systems, have now become one of the hot research topics. In this paper, we study the novel physical responses of nonHermitian systems with anomalous time-reversal symmetry, in both one dimension and two dimensions. Specifically, we focus on whether the systems will exhibit a non-Hermitian skin effect. We employ the theory of generalized Brillouin zone and also numerical methods to show that the anomalous time-reversal symmetry can prevent the skin effect in onedimensional non-Hermitian systems, but is unable to exert the same effectiveness in two-dimensional cases.

关键词： skin effect symmetry non-Hermitian systems

Influence of External Magnetic Field on Anomalous skin effects in Inductively Coupled Plasmas

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2004年第3期21卷 511-513页

作者：毛明王友年 TheStateKeyLaboratoryofMaterialsModification DepartmentofPhysicsDalianUniversityofTechnologyDalian116024

Using a one-dimensional slab model, we study the influence of the external static magnetic field on the anomalous skin effects in the inductively coupled plasma. The rf electromagnetic field in the plasma is determined by solving the linearized Boltzmann equation incorporating the Maxwell equations. The numerical results show that, due to the existence of the external magnetic field, the anomalous skin effects are greatly enhanced and the number of regions with negative absorption is decreased.

关键词： skin effect Anomalous magnetostatic fields Boltzmann equation Inductively coupled plasma exterior magnetic field Maxwell's equations

Numerical investigation of a coupled moving boundary model of radial flow in low-permeable stress-sensitive reservoir with threshold pressure gradient

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第2期25卷 262-270页

作者：刘文超刘曰武牛丛丛韩国锋万义钊 Institute of Mechanics Chinese Academy of Sciences

The threshold pressure gradient and formation stress-sensitive effect as the two prominent physical phenomena in the development of a low-permeable reservoir are both considered here for building a new coupled moving boundary model of radial flow in porous medium. Moreover, the wellbore storage and skin effect are both incorporated into the inner boundary conditions in the model. It is known that the new coupled moving boundary model has strong nonlinearity. A coordinate transformation based fully implicit finite difference method is adopted to obtain its numerical solutions. The involved coordinate transformation can equivalently transform the dynamic flow region for the moving boundary model into a fixed region as a unit circle, which is very convenient for the model computation by the finite difference method on fixed spatial grids. By comparing the numerical solution obtained from other different numerical method in the existing literature, its validity can be verified. Eventually, the effects of permeability modulus, threshold pressure gradient, wellbore storage coefficient, and skin factor on the transient wellbore pressure, the derivative, and the formation pressure distribution are analyzed respectively.

关键词： threshold pressure gradient stress-sensitive effect wellbore storage skin effect

Low-loss wide-bandwidth planar transmission line with a laminated conductor

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2023年第5期66卷 248-256页

作者： Ken NING Xiao-Chun LI Yan SHAO Junfa MAO Key Laboratory of Ministry of Education of Design and Electromagnetic Compatibility of High-Speed Electronic Systems Shanghai Jiao Tong University

In this paper, the laminated conductor technology is first introduced to planar-integrated transmission lines. The laminated conductor is composed of multilayers of metal and insulator, which has a lower conductor loss than a solid conductor. Based on the silicon-based micro electromechanical system technology,a laminated coplanar waveguide(CPW) with wide bandwidth and low loss is proposed, which uses a laminated conductor for signal lines and grounds. A laminated CPW and its transition are designed, fabricated,and measured. The simulation results show that the laminated CPW with many insulator layers has a low conductor loss. The measurement results illustrate that the average insertion loss of the laminated CPW is0.65 d B from DC to 40 GHz, which is 44.4% smaller than that of the solid CPW.

关键词： coplanar waveguide (CPW) laminated conductor conductor loss skin effect silicon-based technology wide-bandwidth

Inhibiting bulging deformation of liquid metal free surface by magnetic pressure

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2021年第7期28卷 818-829页

作者： Yang Li An-yuan Deng Bin Yang Hao Xu En-gang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110004LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110004LiaoningChina

A new method was presented to inhibit bulging deformation and fluctuation of free surface by magnetic pressure.A research combined with numerical and experimental methods was conducted to investigate the feasibility and inhibition *** parameters including magnetic flux density,frequency and action area of magnetic pressure were *** results show that the method is feasible,and the bulged free surface is fully inhibited by the proper magnetic *** inhibition efficiency increases as the increase in magnetic flux density and frequency,which shows a linear rela-tionship with the magnetic flux *** frequency has a great influence on the inhibition efficiency when the frequency is changed from 0.15 to 5.00 ***,the frequency more than 5.00 kHz has little influence on the inhibition efficiency and is recommended in application *** the ratio of the action area to the area of bulged free surface is 0.8,the best inhibition is ***,when the ratio is more than 1.2,a distinct W-shaped free surface is *** surficial and internal flow is strengthened with proper magnetic pressure ***,under the action of magnetic pressure,the fluctuation amplitude of free surface decreases from 4.0 to 1.2 mm and the main fluctuation with frequency of 2.34 Hz is dispersed into several minor fluctuations with frequency of 0.4-4.3 Hz.

关键词： Magnetic pressure High-frequency electromagnetic field Level fluctuation Level deformation skin effect Electromagnetic metallurgy