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Magnetic Switching Dynamics and Tunnel Magnetoresistance Effect Based on Spin-Splitting Noncollinear Antiferromagnet Mn_(3)Pt

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Chinese Physics Letters 2024年第4期41卷 132-138页

作者：朱蒙董建艇李新录郑凡星周晔吴琨张佳 school of Physics and Wuhan National high Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074China

In comparison to ferromagnets,antiferromagnets are believed to have superior advantages for applications in next-generation magnetic storage devices,including fast spin dynamics,vanishing stray fields and robust against external magnetic field,***,unlike ferromagnetic orders,which could be detected through tunneling magnetoresistance effect in magnetic tunnel junctions,the antiferromagnetic order(i.e.,Néel vector)cannot be effectively detected by the similar mechanism due to the spin degeneracy of conventional *** discovered spin-splitting noncollinear antiferromagnets,such as Mn_(3)Pt with momentum-dependent spin polarization due to their special magnetic space group,make it possible to achieve remarkable tunneling magnetoresistance effects in noncollinear antiferromagnetic tunnel *** first-principles calculations,we demonstrate that the tunneling magnetoresistance ratio can reach more than 800% in Mn_(3)Pt/perovskite oxides/Mn_(3)Pt antiferromagnetic tunnel *** also reveal the switching dynamics of Mn_(3)Pt thin film under magnetic fields using atomistic spin dynamic *** study provides a reliable method for detecting Néel vector of noncollinear antiferromagnets through the tunnel magnetoresistance effect and may pave its way for potential applications in antiferromagnetic memory devices.

关键词： tunneling magnetoresistance momentum

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Perception field based imitation learning for unlabeled multi-agent pathfinding

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Science China(Information Sciences) 2024年第5期67卷 115-135页

作者： Wenjie CHU Ailun YU Wei ZHANG Haiyan ZHAO Zhi JIN school of Computer Science Peking University Key Laboratory of high-Confidence Software Technologies (Peking University) Ministry of Education

This paper proposes an imitation learning method to learn a universal agent policy for unlabeled multi-agent pathfinding(unlabeled MAPF) in grid environments. The method transforms the unlabeled MAPF problem into a series of temporal-independent homogeneous classification problems for each *** on this transformation, a neural network is designed to imitate a distance-optimal expert *** neural network consists of two successive modules: perception field learner and field integrating *** former refines and encodes the current system state into a perception field for each agent by combining a set of learnable field-generating functions. The latter takes an agent's perception field as input and decides the agent's next action based on a triplet cross-attention mechanism. We evaluate our method on a diverse set of unlabeled MAPF tasks. Compared with state-of-the-art counterparts, the experimental results manifest the superiority of the proposed method in both generalization ability and scalability.

关键词： unlabeled multi-agent pathfinding perception field triplet cross-attention multi-agent imitation learning learning-based planning

Formal Verification of Data Modifications in Cloud Block Storage Based on Separation Logic

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Chinese Journal of Electronics 2024年第1期33卷 112-127页

作者： Bowen ZHANG Zhao JIN Hanpin WANG Yongzhi CAO Key Laboratory of high Confidence Software Technologies (MOE) School of Computer Science Peking University school of Computer and Artificial Intelligence Zhengzhou University school of Computer Science and Cyber Engineering Guangzhou University

Cloud storage is now widely used, but its reliability has always been a major concern. Cloud block storage(CBS) is a famous type of cloud storage. It has the closest architecture to the underlying storage and can provide interfaces for other types. Data modifications in CBS have potential risks such as null reference or data *** verification of these operations can improve the reliability of CBS to some extent. Although separation logic is a mainstream approach to verifying program correctness, the complex architecture of CBS creates some challenges for verifications. This paper develops a proof system based on separation logic for verifying the CBS data modifications. The proof system can represent the CBS architecture, describe the properties of the CBS system state, and specify the behavior of CBS data modifications. Using the interactive verification approach from Coq, the proof system is implemented as a verification tool. With this tool, the paper builds machine-checked proofs for the functional correctness of CBS data modifications. This work can thus analyze the reliability of cloud storage from a formal perspective.

关键词： Cloud computing Behavioral sciences Reliability Formal verification

Hole mobility enhancement in monolayer WSe2 p-type transistors through molecular doping

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Science China(Information Sciences) 2024年第6期67卷 207-213页

作者： Shiyuan LIU Xiong XIONG Xin WANG Xinhang SHI Ru HUANG Yanqing WU school of Integrated Circuits and Beijing Advanced Innovation Center for Integrated Circuits Peking University Wuhan National high Magnetic Field Center and school of Integrated Circuits Huazhong University of Science and Technology

Two-dimensional （2D） transition metal dichalcogenide （TMDC） semiconductor materials exhibit extraordinary electrical properties,holding promise for the realization of next-generation complementary metal-oxide-semiconductor （CMOS） devices at ultimate ***,constrained by effective device doping strategies,the hole mobility and device performance of tungsten diselenide （WSe2） p-type transistors,especially monolayer chemical vapor deposition （CVD）-grown WSe2,have not met *** this paper,an effective performance enhancement of monolayer WSe2p-type transistor was achieved through a molecular doping *** monolayer WSe2directly on SiO2back-gated substrates and leveraging energy band alignment design,4-nitrobenzenediazonium tetrafluoroborate （4-NBD） molecular dopant with a concentration of 10 m M was utilized to modulate the Fermi level position of monolayer WSe2for hole *** devices demonstrated a more than 98%increase in hole mobility,reaching up to 97 cm2·V-1·s-1while maintaining the current on/off ratio of *** p-type WSe2transistors with 1μm channel length exhibit a high drive current surpassing 176μA·μm-1,exceeding previous CVD-WSe2devices with similar channel *** straightforward and effective approach to improving the electrical performance of WSe2transistors paves the way for advanced logic technologies based on transition metal dichalcogenide semiconductors.

关键词： CVD-grown WSe$_2$ molecular doping 4-NBD p-type transistors hole mobility

highly efficient 1D p-Te/2D n-Bi_(2)Te_(3) heterojunction self-driven broadband photodetector

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Nano Research 2024年第3期17卷 1864-1874页

作者： Chenchen Zhao Dongbo Wang Jiamu Cao Zhi Zeng Bingke Zhang Jingwen Pan Donghao Liu Sihang Liu Shujie Jiao Tianyuan Chen Gang Liu Xuan Fang Liancheng Zhao Jinzhong Wang school of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China school of Astronautics Harbin Institute of TechnologyHarbin 150001China Center for high Pressure Science and Technology Advanced Research Shanghai 201203China State Key Laboratory of high Power Semiconductor Lasers Changchun University of Science and TechnologyChangchun 130022China

Broadband photodetectors with self-driven functions have attracted intensive scientific interest due to their low energy consumption and high optical ***,high-performance broadband self-driven photodetectors are still a significant challenge due to the complex fabrication processes,environmental toxicity,high production costs of traditional 3D semiconductor materials and sharply raised contact resistance,severe interfacial recombination of 2D materials and 2D/3D mixed dimension ***,1D p-Te/2D n-Bi_(2)Te_(3) heterojunctions are constructed by the simple and low-cost hydrothermal method.1D p-Te/2D n-Bi_(2)Te_(3) devices are applied in photoelectrochemical(PEC)photodetectors,with their high performance attributed to the good interfacial contacts reducing interface *** device demonstrated a broad wavelength range(365–850 nm)with an Iph/Idark as high as *** R_(i),D^(*),and external quantum efficiency(EQE)values of the device were as high as 12.07 mA/W,5.87×10^(10) Jones,and 41.05%,respectively,which were significantly better than the performance of the prepared Bi_(2)Te_(3) and Te devices.A comparison of the freshly fabricated device and the device after 30 days showed that 1D p-Te/2D n-Bi_(2)Te_(3) had excellent stability with only 18.08%decay of *** is anticipated that this work will provide new emerging material for future design and preparation of a high-performance self-driven broadband photodetector.

关键词： topological insulating states interfacial recombination self-driven 1D p-Te/2D n-Bi_(2)Te_(3) photodetector

"Suspending Classes Without Stopping Learning":An Initiative to Ensure Learning in Japan During the Pandemic

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ECNU Review of Education 2024年第1期7卷 195-206页

作者：于普姉崎敬吾 Eotvos Lorand University Keigo Anezaki Tokiwagi Gakuen high school

Purpose:During Japan's initial pandemic prevention and control period,the Ministry of Education,Culture,Sports,Science,and Technology of Japan(MEXT)issued several notifications to ensure students'continuous learning according to the"leave no one behind"*** study focused on the comprehensive measures comprising top-level arrangements to implement the"suspending classes without stopping learning"***/Approach/Methods:The study reviewed MEXT's guide on ensuring learning for Japanese primary and secondary school students during the ***:The pandemic has accelerated the development of the information and communications technology educational environment and the implementation of the Global and Innovation Gateway for All(GIGA)schools *** developments laid the foundation for the evolution of diverse pedagogical models and feasible methods for promoting *** home schooling experience during the pandemic provided a natural base for students to practice and foster ***/Value:This paper provides scholars with an understanding of the opportunities and challenges encountered in educational innovation in *** provides insights into the future direction of pedagogical development,capability development,and effective educational arrangements for extraordinary circumstances to facilitate educational development from a broader perspective,particularly under the new normal.

关键词： Continuous learning educational informatization GIGA school Program Japan MEXT pandemic

Cutting performance of saw blades with microtextured rougher and finisher sawteeth

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Advances in Manufacturing 2024年第2期12卷 317-334页

作者： Yang Lu Jian-Xin Deng Zhi-Hui Zhang Jia-Xing Wu Ran Wang Yi-Chen Bao Key Laboratory of high Efficiency and Clean Mechanical Manufacture of MOE School of Mechanical EngineeringShandong UniversityJinan250061People’s Republic of China

The problems of severe sawtooth wear,harsh sawing noise,and low surface quality during the processing of circular saw blades need to be *** improve the cutting performance of TiC-based cermet saw blades,microtextures parallel to the cutting edge were fabricated on rough and fine sawteeth by laser *** cutting tests were performed on a sawing platform under lubricated *** of the sawing arc length and working sawtooth cutting force variations were developed for sawing steel pipes,and the accuracy of the sawing force model was verified *** results indicate that the variations in the sawing force are proportional to the sawing arc *** circular saw blades with microtextures that did not penetrate the sawtooth rake face exhibited the lowest cutting force,sawing noise,and highest machined surface ***,the worn-out distance of the rougher and finisher sawteeth was reduced by approximately 7.4%and 44.1%,respectively,compared with conventional circular saw *** main failure modes of sawteeth were tip wear,rake face adhesion,and oxidative *** addition,the mechanism by which the textures improve the cutting and wear properties of TiC-based circular saw blades was *** study provided a significant concept for enhancing the cutting performance of circular saw blades and improving the machined surface quality.

关键词： Circular saw blades Micro textures Cutting performance Wear performance

Synergistic effect of Co and Co_(6)Mo_(6)C for electroreduction of nitrate to ammonia on Co-MOF derived Co_(6)Mo_(6)C/Co/NC

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Nano Research 2024年第7期17卷 5807-5816页

作者： Xinyan Wang Yue Cao Yan Hai Xiaoman Li Min Luo State Key Laboratory of high-efficiency Utilization of Coal and Green Chemical Engineering School of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021China

Electrocatalytic nitrate reduction reaction(e-NO_(3)RR)offers a promising alternative method for nitrogen cycling and ammonia(NH3)production under ambient ***,the method is still in the dilemma of lowering the reaction overpotential and increasing the reaction *** successfully developed the composition-adjustable Co_(6)Mo_(6)C/Co/N-doped carbon(NC)catalysts by in situ carbonization of Co-based metal-organic framework(MOF)with the constrained phosphomolybdic *** adjusting the ratio of Co0 and Co_(6)Mo_(6)C,Co_(6)Mo_(6)C/Co/NC-3 could satisfy both NO_(3)−conversion at low potential and NH_(x)hydrogenation,and synthesize ammonia efficiently through the synergistic effect of Co0 and Co_(6)Mo_(6)*** achieved an ammonia yield rate as 1233.2μg·h^(−1)·mgcat^(−1)and Faradaic efficiency of NH4+93.6%at−0.33 V *** hydrogen electrode(RHE).Importantly,density functional theory(DFT)calculations and experimental results have demonstrated for the first time the excellent adsorption of nitrite(NO_(2)^(−))by the Mo sites of Co_(6)Mo_(6)C during e-NO_(3)RR,avoiding the undesirable accumulation of NO_(2)^(−).

关键词： synergistic effect nitrate electroreduction Co_(6)Mo_(6)C ammonia synthesis

Interface Design Strategy for GNS/AZ91 Composites with Semi-Coherent Structure

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 467-483页

作者： Jing-Peng Xiong Yi-Qi Zeng Jin-Long Liu Wei-Cheng Wang Lan Luo Yong Liu Key Laboratory of Lightweight and high Strength Structural Materials of Jiangxi Province School of Advanced ManufacturingNanchang UniversityNanchang 330031China school of Physics and Materials Science Nanchang UniversityNanchang 330031China

The interfacial structure plays an important role in the mechanical properties of magnesium matrix composite(MMCs)reinforced with graphene nanosheet(GNS)due to their poor wettability with the Mg *** interface design strategy was proposed to form the semi-coherent interfacial structure with superior bonding *** lattice mismatch and interfacial bonding strength between Mg/rare earth oxide/carbon were utilized as key characteristics to evaluate the interfacial *** oxide(La2O3)was selected as the intermediate candidate due to its low lattice mismatch and high interfacial bonding *** identify the interfacial structure of Mg/La2O3/graphene,first-principles calculations were conducted to calculate the ideal work of separation and electronic structure of the *** demonstrated the presence of strong ionic and covalent interactions at the interface,which theoretically verified the strong interfacial bonding strength among Mg/La2O3/graphene *** experimentally validate the interface strength,MMCs with the interface structure of Mg/La2O3/GNS were *** formation of in-situ La2O3 led to the successful attainment of semi-coherent structures between Mg/La2O3 and La2O3/GNS,resulting in high strength and good ductility of the ***,this work proposes a new approach to interface design in MMCs with an enhancement of mechanical properties.

关键词： Interface design strategy Magnesium matrix composite Graphene nanosheets Semi-coherent interface Mechanical properties