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Low‑Temperature Oxidation Induced Phase Evolution with Gradient Magnetic Heterointerfaces for Superior Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第1期17卷 191-204页

作者： Zizhuang He Lingzi Shi Ran Sun Lianfei Ding Mukun He Jiaming Li Hua Guo Tiande Gao Panbo Liu School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an 710129People’s Republic of China School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072People’s Republic of China

Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching,adjusting dielectric/magnetic resonance and promoting electromagnetic(EM)wave absorption,but still exist a significant challenging in regulating local phase ***,accordion-shaped Co/Co_(3)O_(4)@N-doped carbon nanosheets(Co/Co_(3)O_(4)@NC)with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and lowtemperature oxidation *** results indicate that the surface epitaxial growth of crystal Co_(3)O_(4) domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components,which are beneficial for optimizing impedance matching and interfacial ***,gradient magnetic heterointerfaces simultaneously realize magnetic coupling,and long-range magnetic ***,the synthesized Co/Co_(3)O_(4)@NC absorbents display the strong electromagnetic wave attenuation capability of−53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz,both are superior to those of single magnetic domains embedded in carbon *** design concept provides us an inspiration in optimizing interfacial polarization,regulating magnetic coupling and promoting electromagnetic wave absorption.

关键词： Magnetic heterointerfaces Phase evolution Interfacial polarization Magnetic coupling Electromagnetic wave absorption

Effects of the extrusion parameters on microstructure,texture and room temperature mechanical properties of extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 136-146页

作者： Chenjin Zhang Guangyu Yang Lei Xiao Zhiyong Kan Jing Guo Qiang Li Wanqi Jie State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108China College of Chemistry and Environmental Science Qujing Normal UniversityQujing 655011China

Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed *** dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)*** the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical-rare-earth(RE)*** alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening *** results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.

关键词： Mg-rare earth alloys extrusion temperature extrusion ratio extrusion speed strengthening mechanisms

Stochastic Resonance in an Asymmetric Bistable System Subject to Frequency Mixing Periodic Force and Noise

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Chinese Physics Letters 2005年第5期22卷 1061-1064页

作者：靳艳飞徐伟徐猛 DepartmentofAppliedMathematics NorthwesternPolytechnicalUniversityXi'an710072 DepartmentofAutomaticControl NorthwesternPolytechnicalUniversityXi'an710072 DepartmentofAppliedMathematics NorthwesternPolytechnicalUniversityXi'an710072

The phenomenon of stochastic resonance (SR) in an asymmetric bistable systemsubject to the multiplicative and additive white noises and two periodic fields is *** the two-state theory, analytic expressions of the signal-to-noise ratio (SNR) for fundamentalharmonics and higher harmonics are derived. It is found that SR appears at both fundamentalharmonics and mixed harmonics (of second- and third-order approximation). Moreover, the higher theorder of mixed harmonics is, the larger the SNR values are. The effects of static asymmetry on theSNR (of second- and third-order approximation) are different, and the noise intensity ratio canenhance the SNR for higher harmonics.

关键词： SINGLE-MODE LASER ADDITIVE NOISE LINEAR-SYSTEMS

Defects‑Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第1期17卷 528-547页

作者： Jiaolong Liu Siyu Zhang Dan Qu Xuejiao Zhou Moxuan Yin Chenxuan Wang Xuelin Zhang Sichen Li Peijun Zhang Yuqi Zhou Kai Tao Mengyang Li Bing Wei Hongjing Wu Mengyang Li Bing Wei Hongjing Wu School of Physics Xidian UniversityXi’an 710071People’s Republic of China School of Advanced Materials and Nanotechnology State Key Discipline Laboratory of Wide Band Gap Semiconductor TechnologyXidian UniversityXi’an 710071People’s Republic of China School of Microelectronics Xidian UniversityXi’an 710071People’s Republic of China School of Telecommunication Engineering Xidian UniversityXi’an 710071People’s Republic of China MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary School of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China The Ministry of Education Key Laboratory of Micro and Nano Systems forAerospace School of Mechanical EngineeringNorthwestern PolytechnicalUniversityXi’an 710072People’s Republic of China

Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic *** methods,however,constrain their delicate ***,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon *** unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial ***“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first ***,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric *** defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.

关键词： Defects-rich heterointerfaces Sulfides Polarization coupling Electromagnetic wave absorption

Computer Simulation of the Interphase Boundary Evolution in Ni_(75)Al_xV_(25-x) Alloy

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Journal of Materials Science & Technology 2005年第3期21卷 395-398页

作者： YongshengLI ZhengCHEN YanliLU YongxinWANG SchoolofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi'an710072China SchoolofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXiran710072China//StateKeyLaboratoryofSolidificationProcessingNorthwesternPolytechnicalUniversityXi'an710072China SchoolofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi'an710072China

The interphase boundary evolution of ordered phase in Ni75AlxV25-x alloy during precipitation was simulated on atomic-scale based on the microscopic phase-field dynamic model. The results show that the second phase precipitated from the interphase boundary formed by the first phase and the disordered matrix at high temperature, and from the interphase boundaries of the first phase at low temperature. L12 phase had obvious selective orientation when precipitated from the interphase boundaries of D022- L12 phase nucleated easily at the interphase boundaries formed by [10] and [01] directions of D022 projection along [001] direction, and grew easily at [10] direction. There was no the selective orientation when L12 phase precipitated from the interphase boundary formed by D022 and the disordered matrix. D022 phase had the selective orientation when precipitated from the interphase boundaries of L12, and grew along the [10] direction.

关键词： Microscopic phase-field Atomic-scale Interphase boundary Simulation Ni75AlxV25-x

CdZnTe Energy Levels Induced by Doping of Indium

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Chinese Physics Letters 2004年第2期21卷 367-369页

作者：李国强介万奇谷智杨戈王涛 StateKeyLaboratoryofSolidificationProcessing NorthwesternPolytechnicalUniversityXi'an710072 StateKeyLaboratoryofSolidificationProcessing NorthwesternPolytechnicalUniversityXi'an710072

Photoluminescence (PL) and infrared transmission spectra are used to characterize the In-doped Cd0.9Zn0.1Te (CdZnTe: In). The PL spectrum reveals that there are two other strong emissions situated at 1.54 eV and 1.62 eV except the near band edge emission. This indicates that the doped In can lead to two donor levels of 0.12 eV and 0.04 eV in the CdZnTe band construction, respectively. The IR transmission spectra show that when the wavenumber is larger than 1000cm-1, the CdZnTe: In was almost opaque to the IR emission. Then its IR transmission rapidly increases to 52% when the wavenumber is decreased to 350cm-1 and then keeps to be constant. This confirms the existence of the donor level of 0.12 eV.

关键词： Condensed matter: electrical magnetic and optical

Direct Measurement of the Metastable Liquid Miscibility Gap in Fe-Co-Cu Ternary Alloy System

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Chinese Physics Letters 2005年第2期22卷 482-484页

作者：曹崇德 GeorgP.GOERLER DepartmentofAppliedPhysics NorthwesternPolytechnicalUniversityXi'an710072 DepartmentofAppliedPhysics NorthwesternPolytechnicalUniversityXi'an710072

The metastable liquid-liquid phase separation in undercooled Fe-Co-Cu ternaryalloy melts (X-Cu = 0.10-0.84; X-Co:X-Fe = 1:3, 1:1 and 3:1) is investigated by differentialthermal analysis in combination with glass fluxing technique. In almost every case, the undercoolingof the homogeneous alloy melt was sufficient to reach the boundary line of the submergedmiscibility gap. The differential-thermal-analysis signals indicate that this separation into a(Fe,Co)-rich liquid phase L-1 and a Cu-rich liquid L-2 is exothermic and proceeds until the rapidsolidification of the L-1 phase occurs. At a given Cu concentration and with the increase of Cocontent, the phase separation temperatures decrease monotonically between the corresponding valuesof the boundary systems Fe-Cu and Co-Cu. The boundary lines of the miscibility gap, which aredetermined for the three quasi-binary cross-sections of the (Fe,Co)-Cu alloy system, show remarkablyflat domes. The occurrence of the liquid phase separation shows an evident influence on thesubsequent gamma-Fe(Co,Cu)--> alpha-Fe(Co,Cu) solid phase transformation.

关键词： PHASE-SEPARATION

Computer simulation of interface evolution for an Al-Li alloy during early aging stage

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Rare Metals 2004年第3期23卷 279-285页

作者： TANGLiying WANGYongxin CHENZheng LUYanli ZHANGJianjun DepartmentofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi＇an710072China DepartmentofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi＇an710072China

The nucleation of ordered phase was simulated based on microscopic diffusionequation and the assumptions of the classical nucleation theory were examined. The quantitativecalculations of interface thickness evolution were accomplished for the first time. It was foundthat the interfaces between ordered phase and disordered matrix were diffuse. The interfacethickness decreased with time, from the initial 1.2 nm to an equilibrium value 0.6 nm. The ratios ofthe radius of ordered particles and the interface thickness monotonously increased, but they wereof the same order of magnitude all the time. The sharp interface assumption should not be adopted inthis stage. For the Al-10% Li (atom fraction) alloy aged at 192℃, the assumptions of the classicalnucleation theory disagreed with the facts. The phase transformation followed the non-classicalnucleation mechanism and the applicable scope of the classical nucleation should be confined.

关键词： metal material interface computer simulation non-classical nucleationtheory

掺杂单层MoS_(2)电子结构与光催化性质的第一性原理计算

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原子与分子物理学报 2025年第1期42卷 35-40页

作者：徐启远高朋刘正堂九江学院机械与智能制造学院九江332005 西北工业大学材料学院西安710072

为了提高MoS_(2)的光催化能力,本研究基于第一性原理平面波赝势方法,对Cr、W、Fe、Co、Ni替换单层MoS_(2)晶格中的Mo进行研究.结果表明:W的替换能为正值,Cr、Fe、Co、Ni的替换能为负值.Cr、W掺杂晶格产生畸变主要是杂质原子的共价半径... 详细信息

为了提高MoS_(2)的光催化能力,本研究基于第一性原理平面波赝势方法,对Cr、W、Fe、Co、Ni替换单层MoS_(2)晶格中的Mo进行研究.结果表明:W的替换能为正值,Cr、Fe、Co、Ni的替换能为负值.Cr、W掺杂晶格产生畸变主要是杂质原子的共价半径引起的;Fe、Co、Ni掺杂晶格产生畸变主要是掺杂原子的自旋导致的.Cr、W、Fe、Co、Ni掺杂单层MoS_(2)带隙类型没有发生改变,仍然为直接带隙,但禁带宽度变小,吸收带红移,尤其Fe、Co、Ni掺杂,导带下方有杂质能级使费米能级向高能方向移动,可以作为捕获电子陷阱,增加电子密度,减少光激发电子-空穴对的复合,有利于提升光催化能力.

关键词：掺杂单层二硫化钼光催化电子结构