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Science China(Technological Sciences) 2024年第1期67卷 330-334页

作者： ZHANG DanTong QIAN BinBin XUE DongFeng Multiscale crystal Materials Research Center Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Near-surface cluster active centers(NSCAC)are pivotal functional units in the catalysis of oxygen evolution reaction(OER),which exceeds the limitations imposed by the diverse coordination environments experienced in atomic and molecular active centers,thereby serving as an exceptional medium for exploring the dynamic catalytic processes of metal active sites[1,2].In the OER,the NSCAC primarily consist of the catalytic site and the first neighboring coordinating *** investigation of NSCAC surpasses the exclusive reliance on the electron state regulation mechanism at the atomic level.

关键词： cluster centers exceptional

Growth,optical dispersion and magnetic behavior of Dy^(3+) doped yttrium iron garnet crystals

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Journal of Rare Earths 2024年第6期42卷 1110-1117,I0004页

作者： Yating Fang Hui Shen Yudie Ma Shijie Liao Shuang Xia Tian Tian Ding Zhou Yunfeng Ma Jiayue Xu Institute of crystal Growth School of Materials Science and EngineeringShanghai Institute of Technology National Engineering Center of Electromagnetic Radiation Control Materials School of Electronic Science and EngineeringUniversity of Electronic Science and Technology of China

Y_(3)Fe_(5)O_(12)(YIG)crystals are highly desirable for the fabrication of mid-infrared isolators with the rapid growth of optical communications,although it is rather challenging to grow large size and high-quality single ***^(3+)doping is expected to improve the optical and magneto-optical prope ***,high quality Dy:YIG crystals and the adjustment of Dy^(3+)on the structure and optical behavior of YIG crystal remain unclear,impeding its practical ***,a series of Y_(3-x)Dy_(x)Fe_(5)O_(12)(x=0,0.5,1.0,1.5,3)solid solution crystals was grown by the flux-Bridgman method and single crystals up to 25 mm were *** the introduction of Dy^(3+),lattice parameters are gradually enlarged from 1.2379 nm(YIG)to 1.2420 nm(DyIG).Typical Dy^(3+)absorption peaks are observed around 1070,1265 and 1670 *** refractive index decreases from 2.37(500 nm)to 2.10(2500 nm)for YIG crystal,and it reduces from 2.47(500 nm)to 2.16(2500 nm)for DyIG *** optical bandgaps remain almost unchanged for Dy:YIG *** optical dispersion of the refractive indices was finely fitted by the Wemple and DiDomenico(WDD)and the Sellmeier models,*** the increase of Dy^(3+)content,the saturation magnetization(Ms)decreases significantly from 23.62 emu/g(YIG)to 5.33 emu/g(DyIG).Small coercive field is persisted for this system,endowing small external magnetic *** results provide valuable references for the manipulation of rare earths on the properties of magnetooptical crystals,which is beneficial to the design of high-performance garnet crystals for the application of optical switching and non-reciprocal related devices.

关键词： Magneto-optical crystal Yttrium iron garnet Dy^(3+)doping crystal growth Optical dispersion Rare earths

Simple substituents make big differences in photophysical performances of 2,1,3-benzothiadizole-conjugated spiropyrans

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Chinese Journal of Chemical Engineering 2024年第8期72卷 53-59页

作者： Xiaoming Zhu Yunting Liu Mingyue Cao Guangle Niu State Key Laboratory of crystal Materials Shandong UniversityJinan 250100China School of Chemistry and Chemical Engineering Beijing Institute of TechnologyBeijing 100081China

Developing multifunctional spiropyran dyes is of particular importance in diverse *** the present study,we synthesized two 2,1,3-benzothiadiazole-conjugated spiropyrans(BT-SP-NO2and BTSP-NMe2)with distinct *** donor-acceptor-structured spiropyrans exhibited typical twisted intramolecular charge transfer features and strong emissions in low-polarity solvents with fluorescence quantum yields(QYs)of up to 90.7%.Like traditional spiropyrans,the electron-acceptor-substituted BT-SP-NO2exhibited excellent photochromic behavior under multiple alternating UV—Vis irradiation,while the electron-donor-substituted BT-SP-NMe2was an acidochromic *** addition,the substituent groups distinctly affected the packing modes of these spiropyrans in the solid ***-NMe2showed a much stronger solid-state emission(QY of 59.0%)than ***,these two dyes were utilized as biocompatible probes for the specific light-up imaging of lipid droplets.

关键词： Spiropyran 2,1,3-Benzothiadiazole Photochromism Fluorescent dye Fluorescence imaging

Influence of Nd^(3+) concentration on mid-infrared emission in PbF_(2) crystal co-doped with Ho^(3+) and Nd^(3+) ions

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Journal of Rare Earths 2024年第3期42卷 479-487,I0002页

作者： Yan Chen Juncheng Tan Peixiong Zhang Weibi Zheng Lin Li Lianhan Zhang Zhen Li Yin Hang Zhenqiang Chen Department of Optoelectronic Engineering Jinan UniversityGuangzhou510632China Guangdong Provincial Engineering Research Centerof crystal and Laser technology.Guangzhou 510632China Research Center of Laser crystal Key Laboratory of High Power Laser MaterialsShanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai201800China

A promising series of Ho_(y)Nd_(x)Pb_((1-x-y))F_2(x = 0, 0.01, 0.02, 0.03, 0.04;y = 0.02) crystals was grown by the Bridgman method. The influence of the Nd^(3+)ions concentration on mid-infrared(~2.0, ~2.9 and ~3.9 μm)fluorescence emissions of Ho^(3+)ions in the PbF_(2) crystal excited by 808 nm laser diode was investigated in this work. The energy transfer mechanism between Nd^(3+)ions and Ho~(3+)ions under different concentrations of the Nd^(3+)ions was systematically analyzed. The results show that the Nd^(3+)ions have good sensitization and deactivation effect on the Ho^(3+)ions to stimulate the mid-infrared fluorescence emissions. The experimental analysis proves that the sensitization efficiency of the Nd^(3+)ions is relatively stable at around 93.45% with varying Nd^(3+)-doping concentrations. Concentration dependence studies indicate that the concentration of the Nd^(3+)ions has significant influence on mid-infrared *** the doping concentration of the Nd^(3+)ions is up to 2.0 at%, the intensity of ~2.0, ~2.9 and ~3.9 μm emissions all reach the maximum. The output characteristics of a 3.9 μm laser are simulated, and it is found that with the increase of the Nd^(3+)-doping concentration, the peak power, pulse width, and peak energy all meet the trend of first increasing and then decreasing, and Ho_(0.02)Nd_(0.02)Pb_(0.96)F_(2) crystal displays the best performance. All the results show that the Nd^(3+)/Ho^(3+)co-doped PbF_(2) crystals might act as a useful optical medium for mid-infrared laser applications.

关键词： crystal growth Mid-infrared PbF_(2) Rare earth ions

Shape and composition evolution of Pt and Pt_(3)M nanocrystals under HCl chemical etching

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Chinese Chemical Letters 2024年第9期35卷 403-407页

作者： Lian Sun Honglei Wang Ming Ma Tingting Cao Leilei Zhang Xingui Zhou State Key Laboratory of NBC Protection for Civilian Beijing 102205China Science and technology on Advanced Ceramic Fibers and Composites Laboratory College of Aerospace Science and EngineeringNational University of Defense TechnologyChangsha 410073China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of crystal Materials and Institute of crystal Materials Shandong UniversityJi’nan 250100China

Controlling the shape and composition of Pt-based nanocrystals is essential to improve electrocatalytic *** this work,we have carefully investigated the evolution process of morphology and composition for Pt and Pt_(3)M(M=Ni,Co)nanocrystals by hydrochloric acid(HCl)*** a result,only Pt_(3)Ni nanocrystals successfully formed unsaturated step-like atoms on the surface and then constructed high-index facets(HIFs),while Pt and Pt_(3)Co preserved a good octahedron *** functional theory(DFT)calculation suggests that Cl-ions can be tightly adsorbed on the surface of Pt_(3)Ni rather than other nanocrystals,which hinders the deposition of newly-reduced atoms and thus regulating the surface ***,the etching of surface transitional metals further accelerates the formation of *** by the active sites on the surface,HCl-Pt-Ni exhibited a~10.8 and~11.3 times higher oxygen reduction reaction(ORR)mass and specific activities than commercial Pt/C catalyst,and possessed a good durability after 10,000 cycles *** work gives a deep insight into the design of high-performance Pt-based ORR catalysts.

关键词： Electrocatalysts Nanocrystals Platinum Oxygen reduction reaction DFT calculation

Advancing mid-infrared microdisk laser emission with Tm:YAG

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 91-96页

作者： Zhaocong Wang Huiqi Li Lei Wang Yang Tan Feng Chen School of Physics State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100China

Mid-infrared microcavity lasers have important applications in biosensing,mid-infrared spectroscopy,and environmental ***,the low output power of existing mid-infrared microcavity lasers hinders their practical *** drawback is attributed to the insufficient laser gain medium,which limits the development of mid-infrared whispering-gallerymode(WGM)*** address this issue,we have employed ion implantation-enhanced etching to fabricate Tm:YAG thin films as effective gain media for mid-infrared WGM *** Tm:YAG thin film,with a thickness of 2μm,exhibits excellent fluorescence ***,the Tm:YAG thin film is processed using focused ion beam to form microdisks with a diameter of 30μ*** 785 nm laser pumping,the maximum output power of the Tm:YAG microdisk at 2023.1 nm is229μW,with a slope efficiency of 2.9%.This work demonstrates the outstanding potential of Tm:YAG as a mid-infrared laser gain medium,providing a new option for the development of mid-infrared lasers.

关键词： microdisk microlaser ultrathin film

Parametric investigation of railway fastenings into the formation and mitigation of short pitch corrugation

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Railway Engineering Science 2024年第3期32卷 286-306页

作者： Pan Zhang Shaoguang Li Rolf Dollevoet Zili Li section of Railway Engineering Delft University of TechnologyStevinweg 12628 CN Delftthe Netherlands

Short pitch corrugation has been a problem for railways worldwide over one *** this paper,a parametric investigation of fastenings is conducted to understand the corrugation formation mechanism and gain insights into corrugation mitigation.A three-dimensional finite element vehicle-track dynamic interaction model is employed,which considers the coupling between the structural dynamics and the contact mechanics,while the damage mechanism is assumed to be differential *** fastening models with different configurations,boundary conditions,and parameters of stiffness and damping are built up and *** models may represent different service stages of fastenings in the ***,the effect of train speeds on corrugation features is *** results indicate:(1)Fastening parameters and modelling play an important role in corrugation formation.(2)The fastening longitudinal constraint to the rail is the major factor that determines the corrugation *** fastening vertical and lateral constraints influence corrugation features in terms of spatial distribution and wavelength components.(3)The strengthening of fastening constraints in the longitudinal dimension helps to mitigate ***,the inner fastening constraint in the lateral direction is necessary for corrugation alleviation.(4)The increase in fastening longitudinal stiffness and damping can reduce the vibration amplitudes of longitudinal compression modes and thus reduce the track corrugation *** simulation in this work can well explain the field corrugation in terms of the occurrence possibility and major wavelength *** can also explain the field data with respect to the small variation between the corrugation wavelength and train speed,which is caused by frequency selection and jump between rail longitudinal compression modes.

关键词： Short pitch corrugation Fastening modelling and parameters Corrugation formation and mitigation Rail longitudinal compression modes Finite element vehicle-track interaction model

Angular and planar transport properties of antiferromagnetic V5S8

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Chinese Physics B 2024年第2期33卷 83-88页

作者：吴晓凯王彬吴德桐陈博文弭孟娟王以林沈冰 Center for Neutron Science and technology and School of Physics Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devicesand Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-Sen University School of Integrated Circuits Shandong Technology Center of Nanodevices and Integration State Key Laboratory of Crystal MaterialsShandong University

Systemically angular and planar transport investigations are performed in layered antiferromagnetic(AF) V5S8. In this AF system, obvious anomalous Hall effect(AHE) is observed with a large Hall angle of 0.1 compared to that in ferromagnetic(FM) system. It can persist to the temperatures above AF transition and exhibit strong angular field *** phase diagram reveals various magnetic states by rotating the applied field. By analyzing the anisotropic transport behavior, magnon contributions are revealed and exhibit obvious angular dependence with a spin-flop vanishing line. The observed prominent planar Hall effect and anisotropic magnetoresisitivity exhibit two-fold systematical angular dependent oscillations. These behaviors are attributed to the scattering from spin–orbital coupling instead of nontrivial topological origin. Our results reveal anisotropic interactions of magnetism and electron in V5S8, suggesting potential opportunities for the AF spintronic sensor and devices.

关键词： antiferromagnetism planar Hall effect magnetic and topological properties

Structural,optical and dielectric investigations on RECr_(0.85)Mn_(0.15)O_(3)(RE=Ho,Gd and Pr) nanoparticles

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Journal of Rare Earths 2024年第2期42卷 399-408,I0006页

作者： Komal Kanwar Sonali Pradhan S.Satapathy Yugandhar Bitla Neeraj Panwar Department of Physics Central University of Rajasthan BandarsindrAjmer305817RajasthanIndia Laser Material section HBNIRaja Ramanna Centre for Advanced TechnologyIndore452013India

We hereby report the room-temperature structural and optical characterization of RECr_(0.85)Mn_(0.15)O_(3)(RECMO,RE=Ho,Gd and Pr) compounds synthesized by the auto-combustion sol-gel *** low temperature dielectric properties are also *** RECMO compounds crystallize in an orthorhombic Pbnm symmetry with an average grain size range of 51-80 *** analysis reveals an increase in the structural distortion compared to that of the undoped bulk *** measurements exhibit a significant reduction in bandgap values for RECMO nanoparticles when compared with their undoped bulk ***,from the absorbance measurements various optical parameters such as skin depth,extinction coefficient,refractive index and optical conductivity were also *** dielectric analysis confirms the lower values of the dielectric permittivity and dielectric loss than those of their corresponding bulk *** conductivity versus frequency and temperature data are fitted according to the Jonscher's power law and Arrhenius law,*** small polaron hopping is responsible for the electric conduction in these *** tunability of the optical and dielectric properties as a result of substitution and particle size reduction makes these materials useful for various potential applications in photocatalysis,optoelectronics and low permittivity dielectrics.

关键词： Rare-earth orthochromites Nanoparticles Optical properties Dispersion parameters Dielectric properties Small polaron hopping

Optical edge-to-screw singularity state conversions

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Photonics Research 2024年第8期12卷 1689-1695页

作者： HAOLIN LIN JUNHUI JIA GUOHUA LIU YANWEN HU ZHEN LI ZHENQIANG CHEN SHENHE FU Department of Optoelectronic Engineering Jinan UniversityGuangzhou 510632China Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Guangzhou 510632China Guangdong Provincial Engineering Research Center of crystal and Laser technology Guangzhou 510632China

Optical singularity states,which significantly affect propagation properties of light in free space or optical medium,can be geometrically classified into screw and edge *** different types of singularity states do not exhibit direct connection,being decoupled from each other in the absence of external *** we demonstrate a novel optical process in which a higher-order edge singularity state initially nested in the propagating Gaussian light field gradually involves into a screw singularity with a new-born topological charge determined by order of the edge *** considered edge state comprises an equal superposition of oppositely charged vortex and antivortex *** theoretically and experimentally realize this edge-to-screw conversion process by introducing intrinsic vortex–antivortex *** also present a geometrical representation for mapping this dynamical process,based on the higher-order orbital Poincaré*** this framework,the edge-to-screw conversion is explained by a mapping of state evolution from the equator to the north or south pole of the Poincaré*** demonstration provides a novel approach for manipulating singularity state by the intrinsic vortex–antivortex *** presented phenomenon can be also generalized to other wave systems such as matter wave,water wave,and acoustic wave.

关键词： interaction Poincaré wave