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基于磁梯度场超高分辨的高灵敏加速度传感方法
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作者 王磊 郭浩 +1 位作者 唐军 刘俊 《微纳电子技术》 北大核心 2018年第3期172-177,共6页
报道了一种基于永磁体磁梯度场超高分辨检测机理的加速度传感方法。实验中,通过在聚二甲基硅氧烷(PDMS)柔性薄膜材料中心上表面嵌入永磁体,固定PDMS薄膜周边,悬空永磁体结构,制备了悬臂梁式永磁体质量块结构。通过仿真得到永磁体磁梯... 报道了一种基于永磁体磁梯度场超高分辨检测机理的加速度传感方法。实验中,通过在聚二甲基硅氧烷(PDMS)柔性薄膜材料中心上表面嵌入永磁体,固定PDMS薄膜周边,悬空永磁体结构,制备了悬臂梁式永磁体质量块结构。通过仿真得到永磁体磁梯度场线性分布区域,并在磁梯度场线性分布区域固定磁检测单元,通过检测永磁体在加速度作用下的微位移引起的磁场变化,实现对加速度信息的传感检测。静态测试结果表明在0.866g-1g的测试范围内,加速度传感灵敏度为4.68 Gs/g,加速度的检测分辨能力近似为93μg。 展开更多
关键词 加速度传感方法 磁梯度场 聚二甲基硅氧烷(PDMS)薄膜 重力梯度
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Growth Rate of a-Si∶H Film Influenced by Magnetic Field Gradient in MWECR CVD Plasma System 被引量:2
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作者 胡跃辉 吴越颖 +3 位作者 陈光华 王青 张文理 阴生毅 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第6期613-619,共7页
The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic ... The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic field profiles is obtained quantitatively by using Lorentz fit.The results indicate that the gradient value of the magnetic field profile near by the substrate,which is produced by a coil current with 137.7A if a SmCo permanent magnet is equipped under the substrate holder,is the largest;when the SmCo permanent magnet is taken away,the larger one is produced by the coil current with 137.7A and the smallest one produced by a coil current with 115.2A.High deposition rate of a-Si∶H film is observed near by the substrate with high magnetic field gradient.But uneven deposition rate along the radius of the sample holder is also found by infrared analysis technology when sample is deposited in magnetic field profile,which is produced by the coil current with 137.7A if the SmCo permanent magnet is equipped under the substrate holder. 展开更多
关键词 magnetic field gradient Lorentz fit a-Si∶H film deposition rate MWECR CVD deposition system
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Directional growth behavior of a(Al) dendrites during concentration-gradientcontrolled solidification process in static magnetic field 被引量:2
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作者 李磊 徐博 +6 位作者 佟伟平 何立子 班春燕 张辉 左玉波 朱庆丰 崔建忠 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第7期2438-2445,共8页
The large and small sized Cu(solid)/Al(liquid) couples were prepared to investigate the directional growth behavior of primary a(Al) phase during a concentration-gradient-controlled solidification process under ... The large and small sized Cu(solid)/Al(liquid) couples were prepared to investigate the directional growth behavior of primary a(Al) phase during a concentration-gradient-controlled solidification process under various static magnetic fields(SMFs).The results show that in the large couples,the α(Al) dendrites reveal a directional growth character whether without or with the SMF.However,the 12 T magnetic field induces regular growth,consistent deflection and the decrease of secondary arm spacing of the dendrites.In the small couples,the α(Al) dendrites still reveal a directional growth character to some extent with a SMF of ≤5 T.However,an 8.8 T SMF destroys the directional growth and induces severe random deflections of the dendrites.When the SMF increases to 12 T,the a(Al) dendrites become quite regular despite of the consistent deflection.The directional growth arises from the continuous long-range concentration gradient field built in the melt.The morphological modification is mainly related to the suppression of natural convections and the induction of thermoelectric magnetic convection by the SMF. 展开更多
关键词 α(Al) dendrite diffusion couple concentration gradient field static magnetic field directional growth thermoelectric magnetic convection
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Magnetic field characteristics analysis of a single assembled magnetic medium using ANSYS software 被引量:6
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作者 Ren Liuyi Zeng Shanglin Zhang Yimin 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第3期479-487,共9页
The section shape of an assembled magnetic medium is the most important structural parameter of a high gradient magnetic separator, which directly affects the induction distribution and magnetic field gradient of the ... The section shape of an assembled magnetic medium is the most important structural parameter of a high gradient magnetic separator, which directly affects the induction distribution and magnetic field gradient of the magnetic separator. In this study, equilateral triangle, square, hexagonal, octagon, dodecagon, and round shape sections of the assembled magnetic medium are chosen to study their influence on magnetic field distribution characteristics using the ANSYS analysis. This paper utilizes a single assembled magnetic medium to understand the relationship between the geometry of the assembled magnetic medium and its magnetic field distribution characteristics. The results show that high magnetic field,regional field, magnetic field gradient, and magnetic force formed by the different sections of the assembled magnetic medium in the same background magnetic field reduce in turn based on the triangle,square, hexagonal, octagon, dodecagon, and round. Based on the magnetic field characteristics analytic results, the magnetic separation tests of the ilmenite are carried out. The results indicate that the section shape of the toothed plate compared with the section shape of cylinder can improve the recovery of ilmenite up to 45% in the same magnetizing current condition of 2A, which is consistent with magnetic field characteristics analysis of different assembled magnetic medium section shapes. 展开更多
关键词 Magnetic separation Magnetic medium Magnetic field character High gradient magnetic separator ANSYS
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Three-dimensional conjugate gradient inversion of magnetotelluric full information data 被引量:9
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作者 Lin Chang-Hong Tan Han-Dong Tong Tuo 《Applied Geophysics》 SCIE CSCD 2011年第1期1-10,94,共11页
Based on the analysis of impedance tensor data, tipper data, and the conjugate gradient algorithm, we develop a three-dimensional (3D) conjugate gradient algorithm for inverting magnetotelluric full information data... Based on the analysis of impedance tensor data, tipper data, and the conjugate gradient algorithm, we develop a three-dimensional (3D) conjugate gradient algorithm for inverting magnetotelluric full information data determined from five electric and magnetic field components and discuss the method to use the full information data for quantitative interpretation of 3D inversion results. Results from the 3D inversion of synthetic data indicate that the results from inverting full information data which combine the impedance tensor and tipper data are better than results from inverting only the impedance tensor data (or tipper data) in improving resolution and reliability. The synthetic examples also demonstrate the validity and stability of this 3D inversion algorithm. 展开更多
关键词 MAGNETOTELLURIC full information data 3D inversion conjugate gradient
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Gravitational Shielding Effect in Gauge Theory of Gravity 被引量:1
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作者 WUNing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第4期567-572,共6页
In 1992,E.E.Podkletnov and R.Nieminen found that under certain conditions,ceramic superconductor with composite structure reveals weak shielding properties against gravitational force.In classical Newton's theory ... In 1992,E.E.Podkletnov and R.Nieminen found that under certain conditions,ceramic superconductor with composite structure reveals weak shielding properties against gravitational force.In classical Newton's theory of gravity and even in Einstein's general theory of gravity,there are no grounds of gravitational shielding effects.But in quantum gauge theory of gravity,the gravitational shielding effects can be explained in a simple and natural way.In quantum gauge theory of gravity,gravitational gauge interactions of complex scalar field can be formulated based on gauge principle.After spontaneous symmetry breaking,if the vacuum of the complex scalar field is not stable and uniform,there will be a mass term of gravitational gauge field.When gravitational gauge field propagates in this unstable vacuum of the complex scalar field,it will decays exponentially,which is the nature of gravitational shielding effects.The mechanism of gravitational shielding effects is studied in this paper,and some main properties of gravitational shielding effects are discussed. 展开更多
关键词 gravitational shielding effect symmetry breaking quantum gravity gauge field
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Primary Results of Liquid Metal Free Surface Jet Research
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作者 XU Zengyu PAN Chanjie KANG Weishan 《Southwestern Institute of Physics Annual Report》 2004年第1期101-102,共2页
The liquid metal free surface innovation concept have been considered as liquid metal devices of divertor/limiter and tile of first wall in fusion device because it can withstand over 50 MW·m^2 heating load, is e... The liquid metal free surface innovation concept have been considered as liquid metal devices of divertor/limiter and tile of first wall in fusion device because it can withstand over 50 MW·m^2 heating load, is easily renewed by circulation and many overcome neutron irradiation damage life time limit. There are three types of free surface in the innovation concept as film, curtain (jets or drops) and capillary. The free surface jet is played a more attention at present. But it is no so clear and only a few available data that their magneto-hydrodynamics (MHD) instabilities, interaction with plasma and exclusion of the particles (ions, Alpha particles and so on) from liquid metal, in despite of many liquid metal free surface facilities built and operated especially in US in last two years. Recently, some primary results are carried out at LMEL facility at Southwestern Institute of Physics. 展开更多
关键词 LM free surface MHD instability The gradient magnetic field
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Gradient Microstructure of K4169 Superalloy Prepared by Low Voltage Pulsed Magnetic Field Combined with Directional Solidification 被引量:1
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作者 Li Yingju Zhang Kuiliang +3 位作者 Zhu Cheng Zheng Ce Feng Xiaohui Yang Yuansheng 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2024年第8期2152-2155,共4页
The influence of the low voltage pulsed magnetic field(LVPMF)on the microstructure transition of K4169 superalloy was investigated.The gradient microstructure of K4169 superalloy composed of columnar grains,coarse gra... The influence of the low voltage pulsed magnetic field(LVPMF)on the microstructure transition of K4169 superalloy was investigated.The gradient microstructure of K4169 superalloy composed of columnar grains,coarse grains,and fine grains was prepared through the combined method of LVPMF with directional solidification,which provided a new approach for the preparation of superalloy with gradient microstructure.The distribution of the Lorentz force and flow field under LVPMF effect was simulated,and therefore the microstructure transition mechanism was revealed.Results show that the microstructure transition should be attributed to the coupling effects of the Lorentz force and forced convection. 展开更多
关键词 pulsed magnetic field gradient microstructure SUPERALLOY Lorentz force forced convection
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Investigation of the correlation between internal gradients and dephasing effect in inhomogeneous field 被引量:1
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作者 AN TianLin XIAO LiZhi +2 位作者 LI Xin LIU HuaBing ZHANG ZongFu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第9期1676-1683,共8页
Internal magnetic gradient plays a significant role in Nuclear Magnetic Resonance(NMR)measurements of fluid saturated porous media.The quantitative characterization and application of this physical phenomenon could ef... Internal magnetic gradient plays a significant role in Nuclear Magnetic Resonance(NMR)measurements of fluid saturated porous media.The quantitative characterization and application of this physical phenomenon could effectively improve the accuracy of NMR measurements and interpretations.In this paper,by using the equivalent magnetic dipole method,the three-dimensional distribution of internal induced magnetic field and its gradients in the randomly packed water saturated glass beads are quantitatively characterized.By simulating the diffusive motion of water molecules in porous media with random walk method,the computational dephasing effects equation related to internal gradients is deduced.Thereafter,the echo amplitudes are obtained and the corresponding T2-G spectrum is also inverted.For the sake of verifying the simulation results,an experiment is carried out using the Halbach core analyzing system(B0=0.18 T,G=2.3 T/m)to detect the induced internal field and gradients.The simulation results indicate the equivalent internal gradient is a distribution of 0.1-0.3 T/m,which matched well with the experimental results. 展开更多
关键词 porous media NMR internal gradients dephasing effect inhomogeneous field
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A Novel Magnetic Separation Oxygen-enriched Method and the Influence of Temperature and Magnetic Field on Enrichment 被引量:1
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作者 Li WANG Jun CAI Ping WU Lige TONG Shufeng SUN 《Journal of Thermal Science》 SCIE EI CAS CSCD 2007年第1期79-83,共5页
A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the... A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow without hindrance. Thereby the continuous oxygen enrichment is realized. The results show that the maximum increment of oxygen concentration reaches 0.49% at 298 K when the maximum product of magnetic flux density and field intensity gradient is 563T^2/m. The enrichment level is significantly influenced by the gas temperature and the magnetic field. The maximum increment of oxygen concentration drops to 0.16% when the gas temperature rises to 343 K, and drops to 0.09% when the maximum product of magnetic flux density and gradient is reduced to 101 T^2/m from 563 T^2/m. 展开更多
关键词 magnetic separation oxygen enrichment oxygen separation gradient magnetic field magnetizing force
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Magnetic control: Switchable ultrahigh magnetic gradients at Fe3O4 nanoparticles to enhance solution-phase mass transport 被引量:1
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作者 Kamonwad Ngamchuea Kristina Tschulik Richard G. Compton 《Nano Research》 SCIE EI CAS CSCD 2015年第10期3293-3306,共14页
Enhancing mass transport to electrodes is desired in almost all types of electrochemical sensing, electrocatalysis, and energy storage or conversion. Here, a method of doing so by means of the magnetic gradient force ... Enhancing mass transport to electrodes is desired in almost all types of electrochemical sensing, electrocatalysis, and energy storage or conversion. Here, a method of doing so by means of the magnetic gradient force generated at magnetic-nanoparticle-modified electrodes is presented. It is shown using Fe3O4-nanoparticle-modified electrodes that the ultrahigh magnetic gradients (〉10^8 T·m^- 1) established at the magnetized Fe3O4 nanoparticles speed up the transport of reactants and products at the electrode surface. Using the Fe(Ⅲ)/ Fe(Ⅱ)-hexacyanoferrate redox couple, it is demonstrated that this mass transport enhancement can conveniently and repeatedly be switched on and off by applying and removing an external magnetic properties of magnetite nanoparticles field, owing to the superparamagnetic Thus, it is shown for the first time that magnetic nanoparticles can be used to control mass transport in electrochemical systems. Importantly, this approach does not require any means of mechanical agitation and is therefore particularly interesting for application in micro- and nanofluidic systems and devices. 展开更多
关键词 superparamagneficmagnetite nanoparficles nanoparticle-modifiedelectrodes magnetic field effects MAGNETOELECTROCHEMISTRY
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Reversal of Magnetisation in Ising Ferromagnet by the Field Having Gradient
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作者 Abyaya Dhar Muktish Acharyya 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第11期563-570,共8页
We have studied the reversal of magnetisation in Ising ferromagnet by the field having gradient along a particular direction. We employed the Monte Carlo simulation with Metropolis single spin nip algorithm. The avera... We have studied the reversal of magnetisation in Ising ferromagnet by the field having gradient along a particular direction. We employed the Monte Carlo simulation with Metropolis single spin nip algorithm. The average lifetime of the metastable state was observed to increase with the magnitude of the gradient of applied field. In the high gradient regime, the system was observed to show two distinct region of up and down spins. The interface or the domain wall was observed to move as one increases the gradient. The displacement of the mean position of the interface was observed to increase with the gradient as hyperbolic tangent function. The roughness of the interface was observed to decay exponentially as the gradient increases. The number of spin flip per site was observed to show a discontinuity in the vicinity of the domain wall. The amount of the discontinuity was found to diverge with the system size as a power law fashion with an exponent 5/3. 展开更多
关键词 Ising ferromagnet metastable lifetime Monte Carlo simulation metropolis algorithm
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