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Science China(physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 109-123页

作者： Mingshan Xie Yuchen Wang Haiping Huang PMI lab School of Physics Sun Yat-sen University Guangdong Provincial Key lab.ratory of Magnetoelectric physics and Devices Sun Yat-sen University

Distinct from human cognitive processing, deep neural networks trained by backpropagation can be easily fooled by adversarial examples. To design a semantically meaningful representation learning, we discard backpropagation, and instead, propose a local contrastive learning, where the representations for the inputs bearing the same lab.l shrink(akin to boson) in hidden layers,while those of different lab.ls repel(akin to fermion). This layer-wise learning is local in nature, being biologically plausible.A statistical mechanics analysis shows that the target fermion-pair-distance is a key parameter. Moreover, the application of this local contrastive learning to MNIST benchmark dataset demonstrates that the adversarial vulnerability of standard perceptron can be greatly mitigated by tuning the target distance, i.e., controlling the geometric separation of prototype manifolds.

关键词： machine learning statistical mechanics adversarial robustness neural networks

Studies of Structure Evolution of Nanostructured Hf_(11)Ni_(89) Alloy

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Journal of Materials Science & Technology 1998年第3期14卷 205-210页

作者： Zhenfu DONG and Lianmao PENG(Beijing lab. of Electron Microscopy, Institute of physics and Center for Condensed Matter physics,Chinese Academy of Sciences, P.O.Box 2724, Beijing 100080, China)Ke LU and Zhuangqi HU(State Key lab. for RSA, Institute of Meta Beijing lab. of Electron Microscopy Institute of Physics and Center for Condensed Matter Physics Chinese Academy of Sciences Beijing 100080 P.O.Box 2724 China State Key lab. for RSA Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

A nanostructured Hf11Ni89 ribbon sample was prepared by melt-spinning. It was found that the as-quenched sample is composed of a major HfNi5 compound nanophase and an interfacial magnetic Ni(Hf) solid solution phase. The structure evolution of the sample was studied by using X-ray difFraction (XRD), transmission electron microscopy (TEM), difFerential scanning calorimetry (DSC), resistivity and magnetothermal analysis. Upon heating, a second precipitation process of the Ni(Hf) phase prior to grain growth wa5 detected by means of both structural analysis and physical property measurements. The measurement results are discussed based on the relationship between microstructure and physical properties.

关键词： Studies of Structure Evolution of Nanostructured Hf Alloy Ni

Magnetic transitions and butterfly-shaped hysteresis of Sm-Fe-Al-based perovskite-type orthoferrite

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Journal of Rare Earths 2015年第9期33卷 965-971页

作者： M.A.Ahmed N.G.Imam M.K.Abdelmaksoud Y.A.Saeid Materials Science lab. physics Department Faculty of Science Cairo University Materials Science lab. Experimental physics Department Nuclear Research Center Atomic Energy Authority

A1 doped SmFeO3 （SmFel_xmlxO3; 0.0〈x〈0.15; step 0.05） were prepared by double sintering ceramic technique. The obtained samples were crystallized in single phase structure except the sample with x=0.15. The unit cell volume was found to decrease with increasing AI substitution in orthoferrite. The effective magnetic moment （μeff） and the Curie constant （C） were calculated from the reciprocal of the molar magnetic susceptibility （Z-1） versus absolute temperature plot and found to attain maximum value for the parent sample. The magnetic behavior showed two different magnetic transitions, viz, N6el temperature （TN） and spin reorientation （TsR） transitions. The M-H hysteresis loop of the parent sample took butterfly-shape as a result of different contributions anisotropies. From the magnetic properties measurements, it was obviously found that B-site cation dilution resulted in a drastic decrease in the magnetization. Surprisingly large value of the coercive field was obtained for the undoped sample;Hc=6198.80e. Based on the mentioned results, one can recommend the use of such orthoferrite in magnetic recording media and as pining layer in spin valve for spin- tronic applications.

关键词： SmFeO3 magnetization FESEM crystal structure spintronics spin reorientation butterfly-shaped hysteresis anisotropy rare earths

Surface Degradation of Bulk AlN+Al Nano-composites

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Journal of Materials Science & Technology 1997年第4期13卷 312-314页

作者： Sun, XC Ye, F Song, XP Yang, MC Sun, XK State Key lab. for RSA Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

Bulk AIN + Al nanocomposite materials were synthesized by sintering the compacts of AIN and Al nanoparticles, which were produced by an active plasma-metal reaction method. The surfaces of as-prepared nanocomposite was investigated by X-ray photoelectron spectroscopy (XPS). Results show the surfaces are much degraded and the degradation products are alumina(Al2O3), boehmite(AlOOH), bayerite(AI(OH)(3)) layer. The mechanism of degradation behaviour in moist environment was also discussed.

关键词： Nanostructured materials

Size Distribution of Ti-Fe Nanoparticles

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Journal of Materials Science & Technology 1997年第4期13卷 318-320页

作者： Ye, F Yang, MC Sun, XK Wei, WD State Key lab. for RSA Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

Ti-Fe nanoparticles with different concentrations were synthesized by gas condensation method. It is found that the size distribution of single phase nanoparticles obeys log normal distribution, and that of multiple phase nanoparticles is quite different. If it is assumed that the size distribution of each phase in multiple phase nanoparticles obeys log normal distribution as that of single phase particles, the calculated distribution curve is agreeable to the empirical curve. The inferences from the hypothesis are also supported by experimental results.

关键词： Nanotechnology

ROOM TEMPERATURE D-D FUSION REACTION RATE--A STRONG-COUPLING PLASMA MODEL

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Chinese physics Letters 1989年第8期6卷 343-346页

作者： YAN Xinzhong TSAI Shihtung GUO Shichong ZHANG Zhaoqing Institute of physics Academia SinicaBeijing Center of Theoretical physics CCAST(World Lab.)

A strong-coupling plasma model with ion screening and electron polarization was used to study the room temperature D-D fusion reaction *** using the ground state harmonic-oscillator wave,function,we evaluated the nearest-neighbor penetration probability by WKB *** D-D nuclear fusion re-action rate was *** deuteron density is found to be crucial for the occurrence of fusion reaction while the temperature is much less important.

关键词： method. harmonic RATE

Classical Limit of Quantum Mechanics

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Science China Mathematics 1993年第2期36卷 181-190页

作者：黄湘友 Center of Theoretical physics CCAST (World lab.) Department of Physics Peking University Beijing 100871 PRC

Because of the use of different limiting procedures, there are two conflict conclusions on wave function. One is that a wave function can describe a single particle and the other is that it can only describe an ensemble in the classical limit. In this paper the limiting procedures have been compared. We put the synthesized limit n→∞, (?)→0 but keep E(n,(?)) to be the actual measured value of energy. Under this limit condition, we can not only prove that a wave function can only describe an ensemble, but also can make clear the dynamical behavior of the particles of the ensemble. Calculations show that the reason why quantum mechanics cannot describe a particle is not because of the motion equation but because of the definition of state for the particle.

关键词： classical limit homogeneous ensemble distribution function.

SOLID-STATE HIGH RESOLUTION NMR STUDY ON POLY (2, 6-DIMETHYL-1,4-PHENYLENE OXIDE)

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Chinese Journal of Polymer Science 1995年第3期13卷 252-258页

作者：晏欣胡建治姚树人叶朝辉张宝真 lab. of Polymer Research Naval Academy of Engineering Wuhan 430033 lab. of Magnetic Resonance and Atomic and Molecular physics The Chinese Academy of Sciences Wuhan 430071

Experiments including C-13 spin-lattice relaxation, C-13 heteronuclear dipolar dephasing and H-1 spin diffusion are performed on poly (2,6-dimethyl-1,4-phenylene oxide) (PPO). The results show that the rotation of the methyl groups in solid PPO is partially restricted, which results in a surprisingly efficient spin diffusion between the aromatic proton and methyl proton characterized by a diffusion time of 150 mu s. The results also show that the aromatic ring in solid PPO is rigid and twisted, which causes all aromatic carbons to be chemically unequivalent.

关键词： SOLID-STATE HIGH RESOLUTION NMR C-13 SPIN-LATTICE RELAXATION C-13 HETERONUCLEAR DIPOLAR DEPHASING H-1 SPIN DIFFUSION POLY (2,6-DINIETHYL 1,4-PHENYLENE OXIDE)

A Fast Algorithm for Phase Grating Preparation by Real Space Method

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Journal of Materials Science & Technology 2001年第2期17卷 240-242页

作者： Qiuxiang LIU and Yuanming WANG lab.ratory of Atomic Imaging of Solids, Institute of metal Research, Chinese Academy of Sciences, Shengyang 110015, China Qibin YANG and Xiaohong YAN Institute of Modern physics, Xiangtan University, Xiangtan 411105, China lab. of Atomic Imaging of Solids Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110015 China

Making use of this expression to calculate the phase grating in high resolution image simulation can greatly reduce the calculating time. In this paper, the derivation of the expression is introduced, and then the computer routine is explained in details. Finally the potential projection map of Mg44Rh7 along [001] direction is shown as an illustration. All operations are carried out in real space, so we call the calculation method as the real space method.

关键词： A Fast Algorithm for Phase Grating Preparation by Real Space Method

Microstructural Characteristics of La_(0.7)Ca_(0.3)MnO_3 Films and Multilayers

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Journal of Materials Science & Technology 2000年第6期16卷 601-604页

作者： Mingguang WANG, DouXing LI, Lianlong HE and Hengqiang YE (lab.ratory of Atomic Imaging of Solid, Institute of metal Research, Chinese Academy of Sciences, Shenyang 110015, China) Guangcheng XIONG (Department of physics and Mesoscopic physics National lab. lab. of Atomic Imaging of Solid Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110015 China

La0.7Ca0.3MnO3 (LCMO) films and La0.7Ca0.3MnO3/Gd0.7Ca0.3MnO3 (LCMO/GCMO) multilayers have been prepared by pulsed laser deposition. The microstructures of both systems were investigated by transmission electron microscopy (TEM). The main structure of the films and the multilayers was monoclinic with a unit cell of size 2ap x-2ap. x -2ap, where ap is the lattice constant of single perovskite crystal. The LCMO films were composed of three-dimension multitwinning domains, while the LCMO/GCMO multilayers showed two-domain structure. In LCMO/GCMO multilayers, LCMO layers were coherent with GCMO layers and the interfaces between LCMO and GCMO layers were free from mismatch dislocation, which resulted in highly strained multilayerd structures.

关键词： LCMO Microstructural Characteristics of La MnO3 Films and Multilayers Ca