Since its founding in 1949, the CAS has been in duty bound to settle key S&T problems posed during national economic and defense construction,and has devoted itself to the renewal of China’s traditional industry ...Since its founding in 1949, the CAS has been in duty bound to settle key S&T problems posed during national economic and defense construction,and has devoted itself to the renewal of China’s traditional industry and the development of new technology.In June 1950, the State authorities stipulated that the main tasks for the CAS were "to cultivate versatile S&T workers and a competent work force for national construction, striving to draw close the ties between academic research and actual demands so that science can really serve the country’s industry, agriculture, national defense,展开更多
Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching a...Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching angle shift”, where the applied direct current is assumed to shift, via domain wall depinning during anti-domain expansion, the switching angle of a perpendicular magnetization in a linear proportional manner under a large rotating magnetic field. Here, we report that, for the most commonly employed perpendicular magnetization heterostructures in spintronics(e.g., those based on FeCoB, Co, and Co/Ni multilayers), the switching angle shift considerably misestimates the SOT within the domain wall depinning analysis of the slope of linear-in-current scaling and may also have a non-zero residual value at zero direct current. Our experiments and simulations unveil that the switching angle shift is most likely dominated by chiral asymmetric nucleation rather than expansion of anti-domains. The in-plane field from external magnets and current-induced SOTs lowers the perpendicular nucleation field and thus reduces the required switching angle, ultimately leading to an underestimation of SOTs by domain wall depinning analysis. These results have advanced our understanding of magnetization switching in spintronic devices.展开更多
The empirically reported values of the critical current density (j<sub>c</sub>) of Bi-2212 as 2.4 × 10<sup>5</sup> (j<sub>c</sub><sub>1</sub>;Sample 1) and 1.0 ...The empirically reported values of the critical current density (j<sub>c</sub>) of Bi-2212 as 2.4 × 10<sup>5</sup> (j<sub>c</sub><sub>1</sub>;Sample 1) and 1.0 × 10<sup>6</sup> A/cm<sup>2</sup> (j<sub>c</sub><sub>2</sub>;Sample 2) are intriguing because both of them correspond to the same values of the temperature T = 4.2 K and the applied magnetic field H = 12 × 10<sup>4</sup> G. This difference is conventionally attributed to such factors—not all of which are quantifiable—as the geometry, dimensions and the nature of dopants and the manners of preparation of the samples which cause their granular structures, grain boundaries, alignment of the grains and so on to differ. Based on the premise that the chemical potential μ subsumes most of these features, given herein is a novel explanation of the said results in terms of the values of μ of the two samples. This paper revisits the problem that was originally addressed in [Malik G.P., Varma V.S. (2020) WJCMP, 10, 53-70] in the more accurate framework of a subsequent paper [Malik G.P., Varma V.S. (2021) JSNM, 34, 1551-1561]. Besides, it distinguishes between the contributions of the electro-electron (e-e) and the hole-hole (h-h) pairs to j<sub>c</sub>—a feature to which no heed was paid earlier. The essence of our findings is that the j<sub>c</sub>s of the two samples differ because they are characterized by different values of the primary variables μ<sub>i</sub><sub> </sub>and <img src="Edit_e1b831e9-dc51-4c3b-bd84-fa905e3e62b5.png" alt="" />, where <img src="Edit_1f775a80-30ab-447d-861f-afb4ba8fba6a.png" alt="" /> is the effective mass of a charge-carrier and m<sub>e</sub><sub> </sub>is the free-electron mass and i = 1 and 2 denote Sample 1 and Sample 2, respectively. In the scenario of the charge-carriers being predominantly h-h pairs, the values of these parameters are estimated to be: μ<sub>1</sub> ≈ 12.3 meV, η<sub>1</sub> ≈ 0.58;μ<sub>2</sub> ≈ 22.7 meV, η<sub>2</sub> ≈ 0.94. Following from these and similar estimates when the charge-carriers are e-e pairs, given below for each sample are the detailed results for the values of the secondary variables viz. the number density of the charge-carriers and their critical velocity, the number of occupied Landau levels and the magnetic interaction parameter.展开更多
Electrochemical polishing is the anodic dissolution process without contact with tools,is a surface treatment method to make a surface planarization using an electrochemical reaction with low applied current.The surfa...Electrochemical polishing is the anodic dissolution process without contact with tools,is a surface treatment method to make a surface planarization using an electrochemical reaction with low applied current.The surface quality is mainly affected by the many process parameters.To improve the surface quality,the control of parameters is very important.The aim of this study is to investigate the characteristic of electrochemical polishing effect for inner diameter of Stainless Steel Tube.In order to analyze the characteristics of surface quality were measured in terms of temperature, applied current and machining time.The investigation can enhance the surface quality of inner diameter Stainless Steel Tube.Therefore,we have verified improved results by using selected optimal conditions.展开更多
Transcranial alternating current stimulation(tACS)is a noninvasive neuromodulation technique that regulates brain function by applying sinusoidal alternating currents of specific frequencies to targeted brain regions ...Transcranial alternating current stimulation(tACS)is a noninvasive neuromodulation technique that regulates brain function by applying sinusoidal alternating currents of specific frequencies to targeted brain regions through the scalp electrodes.[1]This guideline aims to evaluate and summarize the efficacy and safety of tACS in clinical applications.We conducted a structured literature search across major databases using the terms“tACS”or“transcranial alternating current stimulation”to identify all relevant literature up to June 2022.展开更多
文摘Since its founding in 1949, the CAS has been in duty bound to settle key S&T problems posed during national economic and defense construction,and has devoted itself to the renewal of China’s traditional industry and the development of new technology.In June 1950, the State authorities stipulated that the main tasks for the CAS were "to cultivate versatile S&T workers and a competent work force for national construction, striving to draw close the ties between academic research and actual demands so that science can really serve the country’s industry, agriculture, national defense,
基金supported by the National Key Research and Development Program of China (Grant No.2022YFA1204000)partly by the National Natural Science Foundation of China (Grant Nos.12274405,12304155,and 12393831)the Beijing Natural Science Foundation (Grant No.Z230006)。
文摘Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching angle shift”, where the applied direct current is assumed to shift, via domain wall depinning during anti-domain expansion, the switching angle of a perpendicular magnetization in a linear proportional manner under a large rotating magnetic field. Here, we report that, for the most commonly employed perpendicular magnetization heterostructures in spintronics(e.g., those based on FeCoB, Co, and Co/Ni multilayers), the switching angle shift considerably misestimates the SOT within the domain wall depinning analysis of the slope of linear-in-current scaling and may also have a non-zero residual value at zero direct current. Our experiments and simulations unveil that the switching angle shift is most likely dominated by chiral asymmetric nucleation rather than expansion of anti-domains. The in-plane field from external magnets and current-induced SOTs lowers the perpendicular nucleation field and thus reduces the required switching angle, ultimately leading to an underestimation of SOTs by domain wall depinning analysis. These results have advanced our understanding of magnetization switching in spintronic devices.
文摘The empirically reported values of the critical current density (j<sub>c</sub>) of Bi-2212 as 2.4 × 10<sup>5</sup> (j<sub>c</sub><sub>1</sub>;Sample 1) and 1.0 × 10<sup>6</sup> A/cm<sup>2</sup> (j<sub>c</sub><sub>2</sub>;Sample 2) are intriguing because both of them correspond to the same values of the temperature T = 4.2 K and the applied magnetic field H = 12 × 10<sup>4</sup> G. This difference is conventionally attributed to such factors—not all of which are quantifiable—as the geometry, dimensions and the nature of dopants and the manners of preparation of the samples which cause their granular structures, grain boundaries, alignment of the grains and so on to differ. Based on the premise that the chemical potential μ subsumes most of these features, given herein is a novel explanation of the said results in terms of the values of μ of the two samples. This paper revisits the problem that was originally addressed in [Malik G.P., Varma V.S. (2020) WJCMP, 10, 53-70] in the more accurate framework of a subsequent paper [Malik G.P., Varma V.S. (2021) JSNM, 34, 1551-1561]. Besides, it distinguishes between the contributions of the electro-electron (e-e) and the hole-hole (h-h) pairs to j<sub>c</sub>—a feature to which no heed was paid earlier. The essence of our findings is that the j<sub>c</sub>s of the two samples differ because they are characterized by different values of the primary variables μ<sub>i</sub><sub> </sub>and <img src="Edit_e1b831e9-dc51-4c3b-bd84-fa905e3e62b5.png" alt="" />, where <img src="Edit_1f775a80-30ab-447d-861f-afb4ba8fba6a.png" alt="" /> is the effective mass of a charge-carrier and m<sub>e</sub><sub> </sub>is the free-electron mass and i = 1 and 2 denote Sample 1 and Sample 2, respectively. In the scenario of the charge-carriers being predominantly h-h pairs, the values of these parameters are estimated to be: μ<sub>1</sub> ≈ 12.3 meV, η<sub>1</sub> ≈ 0.58;μ<sub>2</sub> ≈ 22.7 meV, η<sub>2</sub> ≈ 0.94. Following from these and similar estimates when the charge-carriers are e-e pairs, given below for each sample are the detailed results for the values of the secondary variables viz. the number density of the charge-carriers and their critical velocity, the number of occupied Landau levels and the magnetic interaction parameter.
基金Item Sponsored by INHA UNIVERSITY Research Grant
文摘Electrochemical polishing is the anodic dissolution process without contact with tools,is a surface treatment method to make a surface planarization using an electrochemical reaction with low applied current.The surface quality is mainly affected by the many process parameters.To improve the surface quality,the control of parameters is very important.The aim of this study is to investigate the characteristic of electrochemical polishing effect for inner diameter of Stainless Steel Tube.In order to analyze the characteristics of surface quality were measured in terms of temperature, applied current and machining time.The investigation can enhance the surface quality of inner diameter Stainless Steel Tube.Therefore,we have verified improved results by using selected optimal conditions.
基金supported by grants from the National Key Research and Development Program of China(Nos.2021YFC2501400,2021YFC2501404).
文摘Transcranial alternating current stimulation(tACS)is a noninvasive neuromodulation technique that regulates brain function by applying sinusoidal alternating currents of specific frequencies to targeted brain regions through the scalp electrodes.[1]This guideline aims to evaluate and summarize the efficacy and safety of tACS in clinical applications.We conducted a structured literature search across major databases using the terms“tACS”or“transcranial alternating current stimulation”to identify all relevant literature up to June 2022.
