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Strain-induced modulation of magnetic anisotropy in Co/BaTiO_3 composite

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Chinese Science Bulletin 2014年第36期59卷 5191-5193页

作者： Li Shu ya gao Cewen Nan School of Materials Science and Engineering State Key Laboratory of New Ceramics and Fine Processing Tsinghua University

A uniaxial magnetic anisotropy Co film was grown on a single-crystal Ba Ti O3(BTO) substrate. The strain yielded by the voltage-induced ferroelastic domain switching in the BTO substrate was recorded by atomic force microscope and modulated the magnetism of the Co film. The manipulation of the magnetism of the Co film is experimentally demonstrated by voltage dependence of magnetic hysteresis loops measured via magneto-optic Kerr effect.

关键词：磁各向异性应变诱导调制钛酸钡电压依赖性复合原子力显微镜磁光克尔效应

Resonances for positron–helium and positron–lithium systems in kappa-distribution plasma

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Chinese Physics B 2018年第12期27卷 244-249页

作者： Zi-Shi Jiang ya-Chen gao Key Laboratory of Electronics Engineering College of Heilongjiang ProvinceHeilongjiang Universityand College of Physical Science and TechnologyHeilongjiang UniversityHarbin 150080China Department of Physics Harbin Institute of TechnologyHarbin 150001China Department of Mathematics University of MalayaKuala LampurMalaysia

S-wave resonances of positron–helium and positron–lithium systems in kappa-distribution plasmas are investigated using Hylleraas-type wave functions in the framework of the stabilization method. A model potential approach is used to represent the interactions between the outer electron, the positron and the core. The resonance parameters(position and width) of positron–helium and positron–lithium systems below the Ps(2s) threshold are reported as a function of screening parameter and spectral index of plasma.

关键词： positron–atom scattering kappa-distribution plasmas model potential approach variational method

Probabilistic Teleportation of an Unknown One-Particle State by a Three-Particle General W State

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Communications in Theoretical Physics 2007年第4期47卷 625-628页

作者： XIU Xiao-Ming DONG Li gao ya-Jun Department of Physics Bohai University Jinzhou 121000 China

Two schemes for teleporting an unknown one-particle state are proposed when a general W state is utilized as quantum channel. In the first scheme, after the sender （Alice） makes a Bell-state measurement on her particles, the recipient （Bob） performs a Von Neumann measurement and introduces an auxiliary particle, and carries out a unitary transformation on his particle and the auxiliary particle, and performs a Von Neumann measurement on the auxiliary particle to confirm whether the teleportation succeeds or not. In the second scheme, the recipient （Bob） does not need to perform the first Von Neumann measurement or introduce the auxiliary particle, which is necessary in the first scheme. It is shown that the maxima/probabilities of successful teleportation of the two schemes are identical if the recipient （Bob） performs an appropriate unitary transformation and adopts a proper particle on which he recovers the quantum information of state to be teleported.

关键词： quantum information probabilistic teleportation entanglement general W state

Preparation and Characterization of Fe3O4 Magnetic Nano-particles by ^（60）Co γ-ray Irradiation

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Journal of Materials Science & Technology 2007年第2期23卷 182-184页

作者： Mingcheng yaNG Hongyan SONG Chengshen ZHU Suqin HE ya gao School of Material Science and Engineering Zhengzhou University Zhengzhou 450052 China Isotope Institute of Henan Academy of Sciences Zhengzhou 450015 China

By using a new method, ^60Co γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM） and vibrating sample magnetometer （VSM）, respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation （10 kGy） is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation （10 kGy） are mainly in small cubic shape and the size uniformity of these particles is good.

关键词： ^60Co γ-ray Irradiation Fe304 nano-particles Super-paramagnetism

Grain and dendrite refinement of A356 alloy with Al-Ti-C-RE master alloy

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Rare Metals 2013年第1期32卷 12-17页

作者： Hong-Liang Zhao Jin-Sheng Yue ya gao Kang-Rong Weng College of Materials Science and Engineering Zhengzhou University

Commercial A356 alloy was refined with a homemade A1-5Ti-0.25C-2RE master alloy, and the microstructure and macrostructure of the refined alloy were investigated. The results show that the grain refining effect of A356 is poor by the addition level of 0.5 wt% master alloy, but when the level reaches 3.0 wt% the grain can get a satisfactory refining effect. Dendrite of A356 can be effectively refined by addition of 0.5 wt% master alloy; however, the refining effect is not significantly improved by further increasing the addition of master alloy. Grain and dendrite refining effects are compared in this article, and the results show that the grain and dendrite exhibit different refining effects with the same addition level of master alloy. Dendrite is easier to reach the optimal refining effect than grain.

关键词： A1-Ti-C-RE A356 Grain refiner Secondary dendrite arm spacing (SDAS)

Phase-error restraint with the empirical mode decomposition method in phase measurement profilometry

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Chinese Science Bulletin 2012年第14期57卷 1648-1654页

作者： WEN YongFu CHENG HaoBo gao ya ZHANG HuiJing School of Optoelectronics Beijing Institute of Technology Beijing 100081 China

Phase measurement profilometry(PMP) uses a digital projector and a camera for 3D shape ***,the nonlinear response of the measurement system causes the captured perfect sinusoidal fringe patterns to become non-sinusoidal waveforms,which results in phase and measurement *** perform a theoretical analysis of the phase error resulting from non-sinusoidal fringe *** on a derived phase-error expression,the empirical mode decomposition(EMD) method is introduced to restrain nonlinear phase error and improve the precision in evaluating the phase distribution.A computer simulation and experimental results prove that the proposed method can eliminate possible phase-error in PMP.

关键词：相位测量轮廓术相位误差模式分解法非线性响应三维形状测量经验模式分解数字投影仪计算机仿真

Blockchain-based multi-hop permission delegation scheme with controllable delegation depth for electronic health record sharing

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High-Confidence Computing 2022年第4期2卷 14-22页

作者： ya gao Aiqing Zhang Shu Wu Jindou Chen School of Physics and Electronic Information Anhui Normal UnivresityWuhu 241002China Anhui Provincial Engineering Laboratory on Information Fusion and Control of Intelligent Rabot Wuhu 241002China

Permission delegation has become a new way for data sharing by delegating the authorized permission to other users.A flexible authorization model with strict access control policies is promising for electronic health record(EHR)sharing with *** this paper,a blockchain-based multi-hop permission delegation scheme with controllable delegation depth for EHR sharing has been *** use the interplanetary file system(IPFS)for storing the original *** contracts and proxy re-encryption technology are implemented for permission *** order to ensure data security,we use attribute-based encryption to provide fine-grained access ***,blockchain is used to achieve traceability and *** deploy smart contracts so that the delegation depth can be set by *** analysis of the proposed protocol shows that our solution meets the designed ***,we evaluate the proposed algorithm and implement the scheme on the Ethereum test *** scheme outperforms the competition in terms of performance,according to the results of our experiments.

关键词： Blockchain Data security Permission delegation Access control Smart contract

Hexagonal MBenes-Supported Single Atom as Electrocatalysts for the Nitrogen Reduction Reaction

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Energy Material Advances 2023年第1期4卷 331-343页

作者： ya gao Erpeng Wang yazhuo Zheng Jian Zhou Zhimei Sun School of Materials Science and Engineering Beihang UniversityBeijing 100191China

The electrocatalytic nitrogen reduction reaction(NRR)is currently constrained by sluggish reaction kinetics and poor selectivity because of the difficulties in activating inert N≡N triple bonds and the existence of competing hydrogen evolution reaction(HER).Therefore,electrocatalysts with high activity,selectivity,and stability are highly ***,by means of first-principles calculations,we investigated the electrocatalytic NRR performance of a series of transition metal atoms(e.g.,3d,4d,and 5d)embedded in defective hexagonal MBene nanosheets[h-Zr(Hf)_(2)B_(2)O_(2)]and identified that h-Zr(Hf)_(2)B_(2)O_(2) could be an excellent platform for electrocatalytic *** the basis of our proposed screening criteria,16 candidates are efficiently selected out from 50 systems,among which,Zr_(2)B_(2)O_(2)-Cr stands out with high selectivity to NRR against HER and the ultralow limiting potential(−0.10 V).The value is much lower than that of the well-established stepped Ru(0001)surface(−0.43 V).The origin of the high activity toward NRR is attributed to the synergistic effect of the single atom(SA)and the M atoms in the *** impressively,a composition descriptor is further proposed on the basis of the inherent characteristics of the catalysts[number of valence electrons of SA and electronegativity of the SA and Zr(Hf)atoms],which helps to better predict the catalytic *** work not only contributes to the development of highly efficient NRR electrocatalysts but also extend the application of h-MBenes in electrocatalysis.

关键词： selectivity bonds kinetics

Joint Computation Offloading and Resource Allocation for Mobile-Edge Computing Assisted Ultra-Dense Networks

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Journal of Communications and Information Networks 2022年第1期7卷 96-106页

作者： ya gao Haoran Zhang Fei Yu Yujie Xia Yongpeng Shi School of Physics and Electronic Information Luoyang Normal UniversityLuoyang 471934China

Mobile-edge computing(MEC),enabling to offload computing tasks on mobile devices towards edge servers,can reduce the terminals ***,a single MEC sever usually has limited computing capabilities,which can not meet a large number of terminals’*** this paper,we consider an ultra-dense networks(UDN)scenario where the macro base stations(MBSs)are assisted by MEC *** particular,we first construct system model for MEC assisted UDN,and build the system overhead ***,in order to solve the problem,we transform the problem into three sub-problems,i.e.,offloading strategies subproblem,channel assignments subproblem,and power allocation ***,employing joint offloading and resource allocation algorithms,we obtain the optimal joint strategy for the MEC assisted ***,simulations are conducted to evaluate the performance of our proposed *** results show that obtained algorithms can effectively reduce the energy consumption of the system and improve the overall performance of the system.

关键词： mobile-edge computing(MEC) ultra-dense networks(UDN) task offloading power allocation