The diversity of interface morphologies is observed for directionally solidified Sn-0.65%Cd alloy under a travelling magnetic field （TMF） in the 4 mm-diameter sample. Under an upward TMF, planar and cellular interfa...The diversity of interface morphologies is observed for directionally solidified Sn-0.65%Cd alloy under a travelling magnetic field （TMF） in the 4 mm-diameter sample. Under an upward TMF, planar and cellular interface morphologies transform alternately with increasing magnetic flux density （B≤10.3 mT）. The interface morphology transforms from shallow cellular to deep cellular morphology under a weak downward TMF （B=3.2 mT）. When the magnetic flux density increases further, both sides of the interface morphology appear to be slightly inconsistent, but they roughly tend to be planar under a strong downward TMF （BS10.3 mT）. The interface instability may be attributed to the flow driven by the TMF. Moreover, the shape of interface appears to be almost flat under an upward TMF, but deflective under a downward TMF.展开更多
The magnetic interface forward and inversion method is realized using the Taylor series expansion to linearize the Fourier transform of the exponential function. With a large expansion step and unbounded neighborhood,...The magnetic interface forward and inversion method is realized using the Taylor series expansion to linearize the Fourier transform of the exponential function. With a large expansion step and unbounded neighborhood, the Taylor series is not convergent, and therefore, this paper presents the magnetic interface forward and inversion method based on Pade approximation instead of the Taylor series expansion. Compared with the Taylor series, Pade＇s expansion＇s convergence is more stable and its approximation more accurate. Model tests show the validity of the magnetic forward modeling and inversion of Pade approximation proposed in the paper, and when this inversion method is applied to the measured data of the Matagami area in Canada, a stable and reasonable distribution of underground interface is obtained.展开更多
Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid ...Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.展开更多
Typical cationic and anionic surfactants were chosen and their interactions were calculated by quantum chemical method. Interaction energies are -0.2378 kJ·mol-1, -3.3394kJ·mol-1 and 0.1204kJ·mol-1 for ...Typical cationic and anionic surfactants were chosen and their interactions were calculated by quantum chemical method. Interaction energies are -0.2378 kJ·mol-1, -3.3394kJ·mol-1 and 0.1204kJ·mol-1 for the molecular pairs with fluocarbon and hydrocarbon chain: C4H10/C5H12, C4F10/C5H12, and C4F10 /C5F12, respectively. When hydrophilic group with cationic and anionicions is introduced, interaction energies are -287.40kJ·mol-1, -311.18kJ·mol-1 and -345.83kJ·mol-1. The results show that there is strong static interaction between cationic and anionic surfactants. It has been predicted that mixed monolayer may be formed and surface activity is enhanced favorably, especially for mixtures of cationic and anionic surfactants with fluocarbon and hydrocarbon chains. The anionic surfactants, sodium octadecylbenzenesulfonate perfluopolyetherbenzenesulonate(ANF-I) was synthesized, mixture effects of ANF-I with sodium octadecylbenzenesulfonate or dodecyldimethyl benzylammonium bromide were studied. The results indicate that the efficiency of mixing increased and the theoretical prediction was testified. These results can provide useful information for the design of new surfactants.展开更多
基于自旋转移矩的磁性随机存储器(Spin Transfer Torque-Based Magnetoresistive RAM,STT-MRAM)具有非易失性、可无限擦写和快速写入等优点而有望成为下一代低功耗通用存储器.尤其是近年来STT-MRAM商用芯片的成功问世进一步推动了该器...基于自旋转移矩的磁性随机存储器(Spin Transfer Torque-Based Magnetoresistive RAM,STT-MRAM)具有非易失性、可无限擦写和快速写入等优点而有望成为下一代低功耗通用存储器.尤其是近年来STT-MRAM商用芯片的成功问世进一步推动了该器件的研究与应用.本文首先阐述了MRAM的基本原理与发展历程,着重介绍了写入技术的演变以及磁各向异性的改善.然后总结了近期在3个领域的研究成果:(1)学术界开展了大量研究以探讨制备工艺和器件结构等因素对界面垂直磁各向异性的影响;(2)CoFeB-MgO双界面结构被提出,该结构在不增大写入电流的前提下增强了磁隧道结的热稳定性势垒;(3)新兴的自旋轨道矩写入方式引起了广泛的关注,该技术有望解决传统自旋转移矩所面临的速度瓶颈和势垒击穿风险.最后,本文扼要地介绍了STT-MRAM在芯片设计领域的最新进展.展开更多
Manipulation of spin states via purely electric means forms the research branch "all-electric spintronics".In this paper,we briefly review recent progress relating to the all-electric spintronics,including e...Manipulation of spin states via purely electric means forms the research branch "all-electric spintronics".In this paper,we briefly review recent progress relating to the all-electric spintronics,including electric-field control of Rashba spin-orbit coupling,magnetic anisotropy,exchange bias,ferromagnetism,and other forms of magnetoelectric coupling.Special focus is given to surface/interface systems,including semiconductor(oxide) heterostructures,magnetic/nonmagnetic surfaces,semiconductor-metal interfaces,and other nanostructures,which can be good candidates for functional materials for spintronic.展开更多
Water in the mantle transition zone and the core-mantle boundary plays a key role in Earth’s stratification,volatile cycling,and core formation.If water transportation is actively running between the aforementioned l...Water in the mantle transition zone and the core-mantle boundary plays a key role in Earth’s stratification,volatile cycling,and core formation.If water transportation is actively running between the aforementioned layers,the lower mantle should contain water channels with distinctive seismic and/or electromagnetic signatures.Here,we investigated the electrical conductivity and sound velocity ofε-FeOOH up to 71 GPa and 1800 K and compared them with global tomography data.An abrupt threeorder jump of electrical conductivity was observed above 50 GPa,reaching 1.24(12)×10^(3)S/m at 61 GPa.Meanwhile,the longitudinal sound velocity dropped by 16.8%in response to the high-to-low spin transition of Fe^(3+).The high-conductivity and low-sound velocity ofε-FeOOH match the features of heterogenous scatterers in the mid-lower mantle.Such unique properties of hydrousε-FeOOH,or possibly other Fe-enriched phases can be detected as evidence of active water transportation in the mid-lower mantle.展开更多
基金Project(50774061) supported by the National Natural Science Foundation of ChinaProject(28-TP-2009) supported by the Research Fund of State Key Laboratory of Solidification Processing(NWPU),China
文摘The diversity of interface morphologies is observed for directionally solidified Sn-0.65%Cd alloy under a travelling magnetic field （TMF） in the 4 mm-diameter sample. Under an upward TMF, planar and cellular interface morphologies transform alternately with increasing magnetic flux density （B≤10.3 mT）. The interface morphology transforms from shallow cellular to deep cellular morphology under a weak downward TMF （B=3.2 mT）. When the magnetic flux density increases further, both sides of the interface morphology appear to be slightly inconsistent, but they roughly tend to be planar under a strong downward TMF （BS10.3 mT）. The interface instability may be attributed to the flow driven by the TMF. Moreover, the shape of interface appears to be almost flat under an upward TMF, but deflective under a downward TMF.
基金supported by Sino Probe-09-01-Integrated geophysical data processing and integrated system for moving platform(No.201311192)Graduate innovation fund of Jilin University(No.2015025)
文摘The magnetic interface forward and inversion method is realized using the Taylor series expansion to linearize the Fourier transform of the exponential function. With a large expansion step and unbounded neighborhood, the Taylor series is not convergent, and therefore, this paper presents the magnetic interface forward and inversion method based on Pade approximation instead of the Taylor series expansion. Compared with the Taylor series, Pade＇s expansion＇s convergence is more stable and its approximation more accurate. Model tests show the validity of the magnetic forward modeling and inversion of Pade approximation proposed in the paper, and when this inversion method is applied to the measured data of the Matagami area in Canada, a stable and reasonable distribution of underground interface is obtained.
基金supported by the Natural Science Foundation of China(No.51706190)the State Scholarship Fund of China Scholarship Council。
文摘Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.
文摘Typical cationic and anionic surfactants were chosen and their interactions were calculated by quantum chemical method. Interaction energies are -0.2378 kJ·mol-1, -3.3394kJ·mol-1 and 0.1204kJ·mol-1 for the molecular pairs with fluocarbon and hydrocarbon chain: C4H10/C5H12, C4F10/C5H12, and C4F10 /C5F12, respectively. When hydrophilic group with cationic and anionicions is introduced, interaction energies are -287.40kJ·mol-1, -311.18kJ·mol-1 and -345.83kJ·mol-1. The results show that there is strong static interaction between cationic and anionic surfactants. It has been predicted that mixed monolayer may be formed and surface activity is enhanced favorably, especially for mixtures of cationic and anionic surfactants with fluocarbon and hydrocarbon chains. The anionic surfactants, sodium octadecylbenzenesulfonate perfluopolyetherbenzenesulonate(ANF-I) was synthesized, mixture effects of ANF-I with sodium octadecylbenzenesulfonate or dodecyldimethyl benzylammonium bromide were studied. The results indicate that the efficiency of mixing increased and the theoretical prediction was testified. These results can provide useful information for the design of new surfactants.
文摘基于自旋转移矩的磁性随机存储器(Spin Transfer Torque-Based Magnetoresistive RAM,STT-MRAM)具有非易失性、可无限擦写和快速写入等优点而有望成为下一代低功耗通用存储器.尤其是近年来STT-MRAM商用芯片的成功问世进一步推动了该器件的研究与应用.本文首先阐述了MRAM的基本原理与发展历程,着重介绍了写入技术的演变以及磁各向异性的改善.然后总结了近期在3个领域的研究成果:(1)学术界开展了大量研究以探讨制备工艺和器件结构等因素对界面垂直磁各向异性的影响;(2)CoFeB-MgO双界面结构被提出,该结构在不增大写入电流的前提下增强了磁隧道结的热稳定性势垒;(3)新兴的自旋轨道矩写入方式引起了广泛的关注,该技术有望解决传统自旋转移矩所面临的速度瓶颈和势垒击穿风险.最后,本文扼要地介绍了STT-MRAM在芯片设计领域的最新进展.
基金supported by the National Basic Research Program of China(Grant No.2013CB922300)the National Natural Science Foundation of China(Grant Nos.11004211,61125403 and 50832003)+1 种基金PCSIRT, NCET,ECNU Fostering Project for Top Doctoral DissertationsFundamental Research Funds for the central universities(ECNU)
文摘Manipulation of spin states via purely electric means forms the research branch "all-electric spintronics".In this paper,we briefly review recent progress relating to the all-electric spintronics,including electric-field control of Rashba spin-orbit coupling,magnetic anisotropy,exchange bias,ferromagnetism,and other forms of magnetoelectric coupling.Special focus is given to surface/interface systems,including semiconductor(oxide) heterostructures,magnetic/nonmagnetic surfaces,semiconductor-metal interfaces,and other nanostructures,which can be good candidates for functional materials for spintronic.
基金supported by the Research Start-up Funds of Talents of Sichuan University (1082204112667)China Postdoctoral Science Foundation (18NZ021-0213216308)+6 种基金supported by Spanish Mineco Project (FIS2017-83295-P)supported by the Strategic Priority Research Program of Chinese Academy of Sciences (XDB41000000)supported by the China Academy of Engineering Physics Research Project (CX20210048)a Tencent Xplorer Prizepartially supported by the National Natural Science Foundation of China (42074098)the United Laboratory of High-pressure Physics and Earthquake Science (HPPES202001)the China Academy of Engineering Physics Joint Fund (U1530402)
文摘Water in the mantle transition zone and the core-mantle boundary plays a key role in Earth’s stratification,volatile cycling,and core formation.If water transportation is actively running between the aforementioned layers,the lower mantle should contain water channels with distinctive seismic and/or electromagnetic signatures.Here,we investigated the electrical conductivity and sound velocity ofε-FeOOH up to 71 GPa and 1800 K and compared them with global tomography data.An abrupt threeorder jump of electrical conductivity was observed above 50 GPa,reaching 1.24(12)×10^(3)S/m at 61 GPa.Meanwhile,the longitudinal sound velocity dropped by 16.8%in response to the high-to-low spin transition of Fe^(3+).The high-conductivity and low-sound velocity ofε-FeOOH match the features of heterogenous scatterers in the mid-lower mantle.Such unique properties of hydrousε-FeOOH,or possibly other Fe-enriched phases can be detected as evidence of active water transportation in the mid-lower mantle.
