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Synthesis and nitrogen content regulation of diamond in a high-pressure hydrogen-rich environment
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作者 黄国锋 陈良超 房超 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期541-546,共6页
The regulating nitrogen content of diamond in a hydrogen-rich high-temperature and high-pressure(HPHT) growth environment was systematically investigated in this work by developing three growth systems,namely, "F... The regulating nitrogen content of diamond in a hydrogen-rich high-temperature and high-pressure(HPHT) growth environment was systematically investigated in this work by developing three growth systems,namely, "FeNi+Ti", "FeNi+G_(3)N_(6)H_(6)",and "FeNi+Ti+C_(3)N_(6)H_(6)".Optical microscopy,infrared spectroscopy,and photoluminescence(PL)spectroscopy measurements were conducted to analyze the spectroscopic characteristics of diamonds grown in these three systems.From our analysis,it was demonstrated that the presence of hydrogen in the sp^(3) hybrid C-H does not directly affect the color of the diamond and facilitates the increase of the nitrogen-vacancy(NV) center concentration in a highnitrogen-content diamond.In addition,titanium plays an important role in nitrogen removal,while its impact on hydrogen doping within the diamond lattice is insignificant.Most importantly,by regulating the ratio of nitrogen impurities that coexist in the nitrogen and hydrogen HPHT environment,the production of hydrogenous Ⅱa-type diamond,hydrogenous Ib-type diamond,and hydrogenous high-nitrogen-type diamonds was achieved with a nitrogen content of less than 1 ppm to 1600 ppm. 展开更多
关键词 DIAMOND HPHT superhard material hydrogen-rich environment
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Simulation and test of the SLEGS TOF spectrometer at SSRF 被引量:8
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作者 Kai-Jie Chen Long-Xiang Liu +11 位作者 Zi-Rui Hao Yu-Gang Ma Hong-Wei Wang Gong-Tao Fan Xi-Guang Cao Hang-Hua Xu Yi-Fei Niu Xin-Xiang Li Xin-Rong Hu Yu-Xuan Yang Sheng Jin Pan Kuang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第3期171-184,共14页
The Shanghai laser electron gamma source(SLEGS)is a powerful tool for exploring photonuclear physics,such as giant dipole resonance(GDR)and pygmy dipole resonance,which are the main mechanisms of collective nuclear mo... The Shanghai laser electron gamma source(SLEGS)is a powerful tool for exploring photonuclear physics,such as giant dipole resonance(GDR)and pygmy dipole resonance,which are the main mechanisms of collective nuclear motion.The goal of the SLEGS neutron time-of-flight(TOF)spectrometer is to measure GDR and specific nuclear structures in the energy region above the neutron threshold.The SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and LaBr3 detectors.Geant4 was used to simulate the efficiency of each detector and the entire spectrometer,which provides a reference for the selection of detectors and layout of the SLEGS TOF spectrometer.Under the events of 208Pb,implementations of coincidence and time-of-flight technology for complex experiments are available;thus,and neutron decay events can be separated.The performance of SLEGS TOF spectrometer was systematically evaluated using offline experiments,in which the time resolution reached approximately 0.9 ns. 展开更多
关键词 SLEGS TIME-OF-FLIGHT Photoneutron nuclear reaction
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Diamond growth in a high temperature and high pressure Fe–Ni–C–Si system:Effect of synthesis pressure 被引量:1
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作者 刘杨 王志文 +5 位作者 李博维 赵洪宇 王胜学 陈良超 马红安 贾晓鹏 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第12期602-608,共7页
Pressure is one of the necessary conditions for diamond growth.Exploring the influence of pressure on growth changes in silicon-doped diamonds is of great value for the production of high-quality diamonds.This work re... Pressure is one of the necessary conditions for diamond growth.Exploring the influence of pressure on growth changes in silicon-doped diamonds is of great value for the production of high-quality diamonds.This work reports the morphology,impurity content and crystal quality characteristics of silicon-doped diamond crystals synthesized under different pressures.Fourier transform infrared spectroscopy shows that with the increase of pressure,the nitrogen content in the C-center inside the diamond crystal decreases.X-ray photoelectron spectroscopy test results show the presence of silicon in the diamond crystals synthesized by adding silicon powder.Raman spectroscopy data shows that the increase in pressure in the Fe-Ni-C-Si system shifts the Raman peak of diamonds from 1331.18 cm^(-1)to 1331.25 cm^(-1),resulting in a decrease in internal stress in the crystal.The half-peak width decreased from 5.41 cm^(-1)to 5.26 cm^(-1),and the crystallinity of the silicon-doped diamond crystals improved,resulting in improved quality.This work provides valuable data that can provide a reference for the synthesis of high-quality silicon-doped diamonds. 展开更多
关键词 silicon-doped diamond crystal quality pressure effect nitrogen content
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Revealing the atomic mechanism of diamond–iron interfacial reaction 被引量:1
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作者 Yalun Ku Kun Xu +6 位作者 Longbin Yan Kuikui Zhang Dongsheng Song Xing Li Shunfang Li Shaobo Cheng Chongxin Shan 《Carbon Energy》 SCIE EI CAS CSCD 2024年第3期255-263,共9页
Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide attention.However,researchers found emergent reactions at the interfaces between diamond and ferrous ... Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide attention.However,researchers found emergent reactions at the interfaces between diamond and ferrous materials,which significantly affects the performance of diamond-based devices.Herein,combing experiments and theoretical calculations,taking diamond–iron(Fe)interface as a prototype,the counter-diffusion mechanism of Fe/carbon atoms has been established.Surprisingly,it is identified that Fe and diamond first form a coherent interface,and then Fe atoms diffuse into diamond and prefer the carbon vacancies sites.Meanwhile,the relaxed carbon atoms diffuse into the Fe lattice,forming Fe_(3)C.Moreover,graphite is observed at the Fe_(3)C surface when Fe_(3)C is over-saturated by carbon atoms.The present findings are expected to offer new insights into the atomic mechanism for diamondferrous material's interfacial reactions,benefiting diamond-based device applications. 展开更多
关键词 coherent interface counter-diffusion DIAMOND IRON phase transition
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Tuning Lithiophilicity and Stability of 3D Conductive Scaffold via Covalent Ag-S Bond for High-Performance Lithium Metal Anode
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作者 Xue Liang Li Shaozhuan Huang +8 位作者 Dong Yan Jian Zhang Daliang Fang Yew Von Lim Ye Wang Tian Chen Li Yifan Li Lu Guo Hui Ying Yang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第1期234-241,共8页
Li metal anode holds great promise to realize high-energy battery systems.However,the safety issue and limited lifetime caused by the uncontrollable growth of Li dendrites hinder its commercial application.Herein,an i... Li metal anode holds great promise to realize high-energy battery systems.However,the safety issue and limited lifetime caused by the uncontrollable growth of Li dendrites hinder its commercial application.Herein,an interlayer-bridged 3D lithiophilic rGO-Ag-S-CNT composite is proposed to guide uniform and stable Li plating/stripping.The 3D lithiophilic rGO-Ag-S-CNT host is fabricated by incorporating Ag-modified reduced graphene oxide(rGO)with S-doped carbon nanotube(CNT),where the rGO and CNT are closely connected via robust Ag-S covalent bond.This strong Ag-S bond could enhance the structural stability and electrical connection between rGO and CNT,significantly improving the electrochemical kinetics and uniformity of current distribution.Moreover,density functional theory calculation indicates that the introduction of Ag-S bond could further boost the binding energy between Ag and Li,which promotes homogeneous Li nucleation and growth.Consequently,the rGO-Ag-S-CNT-based anode achieves a lower overpotential(7.3 mV at 0.5 mA cm^(−2)),higher Coulombic efficiency(98.1%at 0.5 mA cm^(−2)),and superior long cycling performance(over 500 cycles at 2 mA cm−2)as compared with the rGO-Ag-CNT-and rGO-CNT-based anodes.This work provides a universal avenue and guidance to build a robust Li metal host via constructing a strong covalent bond,effectively suppressing the Li dendrites growth to prompt the development of Li metal battery. 展开更多
关键词 Ag-S covalent bond electrochemical performances Li dendrite suppression Li metal anode
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Performance analysis of single-focus phase singularity based on elliptical reflective annulus quadrangle-element coded spiral zone plates
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作者 臧华平 王宝珍 +7 位作者 郑程龙 魏来 范全平 王少义 杨祖华 周维民 曹磊峰 郭海中 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期441-448,共8页
Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we pr... Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we propose an efficient methodology to combine the merit of elliptical reflective zone plates(ERZPs) and the advantage of spiral zone plates(SZPs) in establishing a specific single optical element, termed elliptical reflective annulus quadrangle-element coded spiral zone plates(ERAQSZPs) to generate single-focus phase singularity. Differing from the abrupt reflectance of the ERZPs, a series of randomly distributed nanometer apertures are adopted to realize the sinusoidal reflectance. Typically, according to our physical design, the ERAQSZPs are fabricated on a bulk substrate;therefore, the new idea can significantly reduce the difficulty in the fabrication process. Based on the Kirchhoff diffraction theory and convolution theorem, the focusing performance of ERAQSZPs is calculated. The results reveal that apart from the capability of generating optical vortices,ERAQSZPs can also integrate the function of focusing, energy selection, higher-order foci elimination, as well as high spectral resolution together. In addition, the focusing properties can be further improved by appropriately adjusting the parameters, such as zone number and the size of the consisted primitives. These findings are expected to direct a new direction toward improving the performance of optical capture, x-ray fluorescence spectra, and forbidden transition. 展开更多
关键词 optical vortex single-focus spiral zone plate topological charges
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Effect of multiple coulomb scattering on the beam tests of silicon pixel detectors
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作者 Lan-Kun Li Ming-Yi Dong +2 位作者 Ze Gao Liang-Cheng-Long Jin Shu-Jun Zhao 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第4期200-207,共8页
In the research and development of new silicon pixel detectors,a collimated monoenergetic charged-particle test beam equipped with a high-resolution pixel-beam telescope is crucial for prototype verification and perfo... In the research and development of new silicon pixel detectors,a collimated monoenergetic charged-particle test beam equipped with a high-resolution pixel-beam telescope is crucial for prototype verification and performance evaluation.When the beam energy is low,the effect of multiple Coulomb scattering on the measured resolution of the Device Under Test(DUT)must be considered to accurately evaluate the performance of the pixel chips and detectors.This study aimed to investigate the effect of multiple Coulomb scattering on the measured resolution,particularly at low beam energies.Simulations were conducted using Allpix^(2) to study the effects of multiple Coulomb scattering under different beam energies,material budgets,and telescope layouts.The simulations also provided the minimum energy at which the effect of multiple Coulomb scattering could be ignored.Compared with the results of a five-layer detector system tested with an electron beam at DESY,the simulation results were consistent with the beam test results,confirming the reliability of the simulations. 展开更多
关键词 Silicon Pixel Detectors Beam Telescope Multiple Coulomb Scattering Spatial Resolution
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Hole-Doped Nonvolatile and Electrically Controllable Magnetism in van der Waals Ferroelectric Heterostructures
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作者 姜新新 王智宽 +5 位作者 李冲 孙雪莲 杨磊 李冬梅 崔彬 刘德胜 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第5期107-119,共13页
Electrical control of magnetism in van der Waals semiconductors is a promising step towards development of two-dimensional spintronic devices with ultralow power consumption for processing and storing information.Here... Electrical control of magnetism in van der Waals semiconductors is a promising step towards development of two-dimensional spintronic devices with ultralow power consumption for processing and storing information.Here, we propose a design for two-dimensional van der Waals heterostructures(vdWHs) that can host ferroelectricity and ferromagnetism simultaneously under hole doping. By contacting an In Se monolayer and forming an InSe/In_(2)Se_(3) vd WH, the switchable built-in electric field from the reversible out-of-plane polarization enables robust control of the band alignment. Furthermore, switching between the two ferroelectric states(P_↑ and P_↓)of hole-doped In_(2)Se_(3) with an external electric field can interchange the ON and OFF states of the nonvolatile magnetism. More interestingly, doping concentration and strain can effectively tune the magnetic moment and polarization energy. Therefore, this provides a platform for realizing multiferroics in ferroelectric heterostructures,showing great potential for use in nonvolatile memories and ferroelectric field-effect transistors. 展开更多
关键词 polarization FERROELECTRIC DOPING
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Phase reconfiguration of heterogeneous CoFeS/CoNiS nanoparticles for superior battery-type supercapacitors
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作者 Lina Ma Fan Li +7 位作者 Min Zhou Jidong Dong Hao Luo Wei Zhang Wenchao Zhao Xinliang Li Zaixing Jiang Yudong Huang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第9期217-225,共9页
Developing advanced battery-type materials with abundant active sites,high conductivity,versatile morphologies,and hierarchically porous structures is crucial for realizing high-quality hybrid supercapacitors.Herein,h... Developing advanced battery-type materials with abundant active sites,high conductivity,versatile morphologies,and hierarchically porous structures is crucial for realizing high-quality hybrid supercapacitors.Herein,heterogeneous FeS@NiS is synthesized by cationic Co doping via surface-structure engineering.The density functional theory(DFT)theoretical calculations are firstly performed to predict the advantages of Co dopant by improving the OH^(−)adsorption properties and adjusting electronic structure,benefiting ions/electron transfer.The dynamic surface evolution is further explored which demonstrates that CoFeS@CoNiS could be quickly reconstructed to Ni(Co)Fe_(2)O_(4)during the charging process,while the unstable structure of the amorphous Ni(Co)Fe_(2)O_(4)results in partial conversion to Ni/Co/FeOOH at high potentials,which contributes to the more reactive active site and good structural stability.Thus,the free-standing electrode reveals excellent electrochemical performance with a superior capacity(335.6 mA h g^(−1),2684 F g^(−1))at 3 A g^(−1).Furthermore,the as-fabricated device shows a quality energy density of 78.1 W h kg^(−1)at a power density of 750 W kg^(−1)and excellent cycle life of 92.1%capacitance retention after 5000 cycles.This work offers a facile strategy to construct versatile morphological structures using electrochemical activation and holds promising applications in energy-related fields. 展开更多
关键词 In-situ reconfiguration Heterogeneous design Battery-type supercapacitors Superior performance Sulphide
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Preparation of fluorescence starch-nanoparticle and its application as plant transgenic vehicle 被引量:6
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作者 刘俊 王凤华 +4 位作者 王玲玲 肖苏尧 童春意 唐冬英 刘选眀 《Journal of Central South University of Technology》 EI 2008年第6期768-773,共6页
Starch-nanoparticles were synthesized in water-in-oil microemusion at room temperature, and the starch-nanoparticles were coated with poly-L-lysine. The surface of the starch-nanoparticles was combined with fluorescen... Starch-nanoparticles were synthesized in water-in-oil microemusion at room temperature, and the starch-nanoparticles were coated with poly-L-lysine. The surface of the starch-nanoparticles was combined with fluorescence material Ru(bpy)32+·6H2O, and then the particles were characterized via transmission electron microscope. The fluorescence nanoparticles were conjugated with plasmid DNA to form complexes, and then treated with ultrasound and DNase I. pEGAD plasmid DNA-nanoparticle complexes were co-cultured with plant suspension cells of Dioscrea Zigiberensis G H Wright, and treated with ultrasound. The results show that the diameter of the fluorescence starch-nanoparticles is 50-100 nm. DNA-nanoparticle complexes can protect DNA from ultrasound damage as well as from DNase I cleavage. Mediated by ultrasound, pEGAD plasmid DNA-nanoparticle complexes can pierce into the cell wall, cell membrane and nucleus membrane of plant suspension cells. The green fluorescence protein(GFP) gene at a high frequency exceeds 5%. This nano-biomaterial can efficiently solve the problem that exterior genes cannot traverse the plant cell wall easily. 展开更多
关键词 fluorescence nanoparticle PLANT gene vehicle ultrasound-mediation transformation
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Fabrication of PdSe2/GaAs Heterojunction for Sensitive Near-Infrared Photovoltaic Detector and Image Sensor Application 被引量:3
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作者 Lin-bao Luo Xiu-xing Zhang +6 位作者 Chen Li Jia-xiang Li Xing-yuan Zhao Zhi-xiang Zhang Hong-yun Chen Di Wu Feng-xia Liang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第6期733-742,I0003,共11页
In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaA... In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaAs heterojunction device exhibited obvious photovoltaic behavior to 808 nm illumination,indicating that the near-infrared photodetector can be used as a self-driven device without external power supply.Further device analysis showed that the hybrid heterojunction exhibited a high on/off ratio of 1.16×10^5 measured at 808 nm under zero bias voltage.The responsivity and specific detectivity of photodetector were estimated to be 171.34 mA/W and 2.36×10^11 Jones,respectively.Moreover,the device showed excellent stability and reliable repeatability.After 2 months,the photoelectric characteristics of the near-infrared photodetector hardly degrade in air,attributable to the good stability of the PdSe2.Finally,the PdSe2/GaAs-based heterojunction device can also function as a near-infrared light sensor. 展开更多
关键词 van der Waals heterojunction Two dimensional materials Near-infrared light photodetector Image sensor RESPONSIVITY
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Analysis and simulation of lateral PIN photodiode gated by transparent electrode fabricated on fully-depleted SOI film 被引量:2
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作者 谢海情 曾云 +1 位作者 曾健平 王太宏 《Journal of Central South University》 SCIE EI CAS 2011年第3期744-748,共5页
A novel device, lateral PIN photodiode gated by transparent electrode (LPIN PD-GTE) fabricated on fully-depleted SOI film was proposed. ITO film was adopted in the device as gate electrode to reduce the light absorp... A novel device, lateral PIN photodiode gated by transparent electrode (LPIN PD-GTE) fabricated on fully-depleted SOI film was proposed. ITO film was adopted in the device as gate electrode to reduce the light absorption. Thin Si film was fully depleted under gate voltage to achieve low dark current and high photo4o-dark current ratio. The model of gate voltage was obtained and the numerical simulations were presented by ATLAS. Current-voltage characteristics of LPIN PD-GTE obtained in dark (dark current) and under 570 nm illumination (photo current) were studied to achieve the greatest photo-to-dark current ratio for active channel length from 2 to 12 /am. The results show that the photo-to-dark current ratio is 2.0×10^7, with dark current of around 5×10^-4 pA under VGK=0.6 V, PrN=5 mW/cm2, for a total area of 10μm×10μm in fully depleted SOI technology. Thus, the LPIN PD-GTE can be suitable for high-grade photoelectric systems such as blue DVD. 展开更多
关键词 lateral PIN photodiode transparent electrode physical model photo-to-dark current ratio SILICON-ON-INSULATOR
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Structural and electronic properties of Fe-doped BaTiO3 and SrTiO3 被引量:2
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作者 张超 王春雷 +1 位作者 李吉超 杨鲲 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第5期1422-1428,共7页
We have performed first principles calculations of Fe-doped BaTiO3 and SrTiO3. Dopant formation energy, structure distortion, band structure and density of states have been computed. The dopant formation energy is fou... We have performed first principles calculations of Fe-doped BaTiO3 and SrTiO3. Dopant formation energy, structure distortion, band structure and density of states have been computed. The dopant formation energy is found to be 6.8eV and 6.5eV for Fe-doped BaTiO3 and SrTiO3 respectively. The distances between Fe impurity and its nearest O atoms and between Fe atom and Ba or Sr atoms are smaller than those of the corresponding undoped bulk systems. The Fe defect energy band is obtained, which mainly originates from Fe 3d electrons. The band gap is still an indirect one after Fe doping for both BaTiO3 and SrWiO3, but the gap changes from Γ-R point to Γ-X point. 展开更多
关键词 the first-principles IMPURITY BATIO3 SRTIO3
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Surface rumples and band gap reductions of cubic BaZrO_3 (001) surface studied by means of first-principles calculations 被引量:2
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作者 张超 王春雷 +3 位作者 李吉超 杨鲲 张艳飞 吴清早 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第1期274-280,共7页
Electronic properties of the (001) surface of cubic BaZrO3 with BaO and ZrO2 terminations have been studied using first-principles calculations. Surface structure, partial density of states, band structure and surfa... Electronic properties of the (001) surface of cubic BaZrO3 with BaO and ZrO2 terminations have been studied using first-principles calculations. Surface structure, partial density of states, band structure and surface energy have been obtained. We find that the largest relaxation appears in the first layer of atoms, and the relaxation of the BaO-terminated surface is larger than that of the ZrO2-terminated surface. The surface rumpling of the BaO-terminated surface is also larger than that of the ZrO2-terminated surface. Results of surface energy calculations reveal that the BaZrO3 surface is likely to be more stable than the PbZrO3 surface. 展开更多
关键词 SURFACE band gap BaZrO3 FIRST-PRINCIPLES
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Effect of platform temperature on microstructure and corrosion resistance of selective laser melted Al-Mg-Sc alloy plate 被引量:2
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作者 LI Meng-jia LIAN Juan +4 位作者 CAO Ling-fei SHI Yun-jia ZHANG Guo-peng WANG Jie-fang ROMETSCH Paul 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第3期999-1014,共16页
The Al-3.40Mg-1.08Sc alloy plates were manufactured by selective laser melting(SLM) at platform temperatures of 35 ℃ and 200 ℃, respectively, and the corrosion performance of them was studied along height direction.... The Al-3.40Mg-1.08Sc alloy plates were manufactured by selective laser melting(SLM) at platform temperatures of 35 ℃ and 200 ℃, respectively, and the corrosion performance of them was studied along height direction. The results show that the corrosion resistance of the alloy plate built at platform temperature of 35 ℃ along height direction is basically the same due to a uniform microstructure;While the corrosion resistance of the alloy plate built at platform temperature of 200 ℃ along height direction is different. The evolution of microstructure and the distribution of secondary phases are investigated, and the results show that the Cu-rich phases in alloy play a key role on corrosion performance. At higher platform temperature, the cooling rate is relative slow and a certain degree of in situ ageing leads to the significantly different distribution of Cu-rich phases along grain boundary. Specimens built at the platform temperature of 200 ℃ are inclined to locate at the crossed grain boundary, rather than continuous segregation of Cu-rich phases along grain boundary that is built at platform temperature of 35 ℃. Therefore, the corrosion resistance of Al-3.40Mg-1.08Sc alloy plate manufactured at platform temperature of 200 ℃ is higher, and presents a gradually decreasing trend along height direction. 展开更多
关键词 selective laser melting aluminum alloys MICROSTRUCTURE corrosion resistance platform temperature
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Magnetic and Transport Properties of La_(0.5-x)Nd_xBa_(0.5) CoO_3 Compounds 被引量:1
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作者 张汝贞 刘宜华 +3 位作者 王成建 黄宝歆 季刚 梅良模 《Journal of Rare Earths》 SCIE EI CAS CSCD 2003年第5期558-562,共5页
Substituting effects of Nd for La in La 0.5 Ba 0.5 CoO 3 compounds were studied systematically. The results show that Nd doping does not change the itinerant properties of the Co3d electrons. The molecular ma... Substituting effects of Nd for La in La 0.5 Ba 0.5 CoO 3 compounds were studied systematically. The results show that Nd doping does not change the itinerant properties of the Co3d electrons. The molecular magnetic moment of the materials decreases monotonically with increasing Nd dopant. When Nd content x ≥0.45, a magnetic phase separation appears in the materials. When x ≤0.45, the Curie temperature decreases monotonically with increasing Nd dopant. This is due to the size effects of the rare earth ions. The electric resistance measurements show that in the studied temperature range, the conduction of the materials belongs to the thermo diffusion conduction below the Curie temperature, while it belongs to the variable range hopping conduction of polarons over the Curie temperature. 展开更多
关键词 metal materials La 0.5- x Nd x Ba 0.5 CoO 3 compounds size effect itinerant electrons charge transfer rare earths
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Nonlinear Electrical Characteristics of Antimony and Copper Doped Tin Oxide Based Varistor Ceramics 被引量:1
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作者 王春明 王矜奉 苏文斌 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第3期728-731,共4页
The novel CuO-doped dense tin oxide varistor ceramics are investigated. The densification of tin oxide varistor ceramics could be greatly improved by doping copper oxide additives. The introduction of antimony additiv... The novel CuO-doped dense tin oxide varistor ceramics are investigated. The densification of tin oxide varistor ceramics could be greatly improved by doping copper oxide additives. The introduction of antimony additives into a SnO2. CuO ceramic system would make it possess excellent nonlinearity. The sample doped with 0.05 mol% Sb2 03 possesses the highest nonlinearity coefficient (α = 17.9) and the lowest leakage current density ( JL = 52μA cm^-2) among all the samples. A modified defect barrier model is introduced to explain the formation of the grainboundary barrier. The nonlinear behaviour of (Cu, Sb)-doped SnO2 varistor system could be explained by the barrier model. 展开更多
关键词 GRAIN-BOUNDARIES SYSTEM BEHAVIOR OXYGEN SIZE
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Synthesis and biochemical properties of fluorescent/magnetic bifunctional starch particles 被引量:1
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作者 王凤华 刘俊 +6 位作者 唐冬英 薛昌刚 肖苏尧 郑元青 童春义 王玲玲 刘选明 《Journal of Central South University》 SCIE EI CAS 2010年第2期211-217,共7页
Magnetic starch particles (MSPs) were synthesized in water-in-oil mieroemulsion at room temperature. MSPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FTI... Magnetic starch particles (MSPs) were synthesized in water-in-oil mieroemulsion at room temperature. MSPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FTIR), zeta potential system, thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM). The average diameter of the MSPs was 220 nm, dispersed with well-proportioned size and magnetic resonance, the saturation magnetization was 3.64 A.mR/kg. MSP was coated with poly-L-lysine (PLL), and then the surface of PLL-MSP was combined with fluorescein isothiocynate (FITC). Results show that fluorescent/magnetic starch particles (FMSPs) are of stable photo-bleaching capability compared with free FITC, with low bio-toxicity and certain function of magnetic separation. It is expected that FMSPs are bifimctional nano-materials including fluorescence labelling and magnetic separation. 展开更多
关键词 starch-particles NANO-MATERIALS SYNTHESIS fluorescent properties magnetic properties biochemical properties
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Synthesis and Field Emission of ZnO Nanostructures on CuO Catalyzed Porous Silicon Substrate 被引量:1
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作者 郁可 张永胜 +6 位作者 欧阳世翕 张清杰 罗来强 张秋香 常中坤 李立君 朱自强 《Chinese Physics Letters》 SCIE CAS CSCD 2005年第9期2411-2414,共4页
Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon (PS) using a simple vapour-solid (VS) growth method. A comparison of their morphologies is ... Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon (PS) using a simple vapour-solid (VS) growth method. A comparison of their morphologies is investigated by scanning electron microscopy (SEM). The transmission electron microscopy (TEM) confirms that ZnO nanobelts and nanorods are single crystalline with the growth direction of (0110) and (0001), respectively. Field emission tests indicate that the ZnO nanostructures on porous silicon have low turn-on field of about 3.6 V/μm (at 1.0μA/cm^2) and the threshold field of about 8.3 V/μm (at 1.0mA/cm^2), high emission site density (ESD) of approximately 104 cm^-2. 展开更多
关键词 ZINC-OXIDE NANOWIRES ROOM-TEMPERATURE GROWTH PHOTOLUMINESCENCE NANORODS FILMS
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Microstructures and corrosion behaviors of Al−6.5Si−0.45Mg−xSc casting alloy 被引量:1
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作者 Yu-kun MA Ming-xing WANG +1 位作者 Ya-nan LIU Bin CAI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第2期424-435,共12页
The microstructures and corrosion behaviors of the Al−6.5Si−0.45Mg casting alloys with the addition of Sc were investigated by using scanning electron microscopy,X-ray diffraction,electrochemical measurement technique... The microstructures and corrosion behaviors of the Al−6.5Si−0.45Mg casting alloys with the addition of Sc were investigated by using scanning electron microscopy,X-ray diffraction,electrochemical measurement techniques and immersion corrosion tests and compared with those of Sr-modified alloy.The results show that Sc has evident refining and modifying effects on the primaryα(Al)and the eutectic Si phase of the alloy,and the effects can be enhanced with the increase of Sc content.When the Sc content is increased to 0.58 wt.%,its modifying effect on the eutectic Si is almost same as that of Sr.Sc can improve the corrosion resistance of the test alloy in NaCl solution when compared with Sr,but the excessively high Sc content cannot further increase the corrosion resistance of the alloy.The corrosion of the alloys mainly occurs in the eutectic region of the alloy,and mostly the eutecticα(Al)is dissolved.This confirms that Si phase is more noble thanα(Al)phase,and the galvanic couplings can be formed between the eutectic Si andα(Al)phases. 展开更多
关键词 Al−Si−Mg casting alloy scandium(Sc) α(Al)phase eutectic Si phase corrosion resistance
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