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Effect of Anion Surface Active Agent on the Preparation of SrTiO_3 Nano-Crystals 被引量:1
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作者 Qingli Ren Qiang Luo Quanxi Cao 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第A03期603-604,共2页
SrTiO_3 nano-crystal samples with floccule or flake crystal morphology,which were indexed as a perovskite-type crystal structure based on the results of XRD and TEM,were successfully prepared by one-step liquid reacti... SrTiO_3 nano-crystal samples with floccule or flake crystal morphology,which were indexed as a perovskite-type crystal structure based on the results of XRD and TEM,were successfully prepared by one-step liquid reaction method.And the growth mechanism of the SrTiO_3 nano-crystals under the liquid condition with/without adding the surface active agent was investigated.It was found that adding the surface active agent contributes to the processing in which the ions gathering bodies transit to a more stable phase through the chemical reaction and form the flake SrTiO_3 nano-crystals. 展开更多
关键词 nano-crystals SRTIO3 anion surface active agent technology processing
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Up-conversion luminescence properties and energy transfer of Er^(3+)/Yb^(3+)co-doped oxyfluoride glass ceramic containing CaF_2 nano-crystals 被引量:1
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作者 马辰硕 焦清 +4 位作者 李龙基 周大成 杨正文 宋志国 邱建备 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第5期574-578,共5页
The Er^3+/yb^3+ co-doped transparent oxyfluoride glass-ceramics containing CaF2 nano-crystals were successfully prepared. After heat treatments, transmission electron microscopy (TEM) images showed that CaF2 nano-... The Er^3+/yb^3+ co-doped transparent oxyfluoride glass-ceramics containing CaF2 nano-crystals were successfully prepared. After heat treatments, transmission electron microscopy (TEM) images showed that CaF2 nano-crystals of 20-30 nm in diameter precipitated uniformly in the glass matrix. luminescence of Er^3+ at 540 nm and 658 nm was observed in Comparing with the host glass, high efficiency upconversion the glass ceramics under the excitation of 980 nm. Moreover, the size of the precipitated nano-crystals can be controlled by heat-treatment temperature and time. With the increase of the nano-crystal size, the intensity of the red emission increased more rapidly than that of the green emission. The energy transfer process of Er^3+ and Yb^3+ was convinced and the possible mechanism of Er^3+ up-conversion was discussed. 展开更多
关键词 nano-crystals up-conversion luminescence Er^3+/Yb^3+ co-doped glass ceramics
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Fabrication and Characteristics of Nano-Floating Gate Memories with ZnO Nano-Crystals as Charge-Storage Layer
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作者 Lu Liu Yong Su +1 位作者 Jing-Ping Xu Yi-Xian Zhang 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第6期102-105,共4页
Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force ... Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force microscopy and scanning electron microscopy reveal the morphology of discrete ZnO nano-crystals.For capacitance-voltage measurements,it is found that the memory device with 1.5 nm ZnO and annealed at 700℃shows a larger memory window of 4.3 V(at±6 V)and better retention characteristics than memoriy devices with2.5 nm ZnO or annealed at other temperatures.These results indicate that the nano-floating gate memory with ZnO nano-crystals can obtain good trade-off memory properties. 展开更多
关键词 ZNO Fabrication and Characteristics of Nano-Floating Gate Memories with ZnO nano-crystals as Charge-Storage Layer
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Grain evolution of nano-crystals ZnO under HP and HT 被引量:1
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作者 SHAO Guangjie1, QIN Xiujuan1, LIU Riping1, WANG Wenkui1,2 & YAO Yushu2 1. Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China 2. Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2006年第3期281-290,共10页
Grain evolution of nano-crystals ZnO under high temperature and pressure is studied using a cubic high pressure apparatus. The structure, grain sizes and morphology of the samples are characterized by X-ray diffractio... Grain evolution of nano-crystals ZnO under high temperature and pressure is studied using a cubic high pressure apparatus. The structure, grain sizes and morphology of the samples are characterized by X-ray diffraction and field emission scanning electron microscopy. The results show that the grain sizes of ZnO grow rapidly at temperature 200℃ under pressure. At temperature lower than 300 ℃ (including 300 ℃), the grain sizes of the samples first increase with the pressure increasing from 1 to 3 GPa and later de- crease from 4 to 6 GPa. The activation volume from 1 to 3 GPa and from 4 to 6 GPa is calculated respectively using the phenomenological kinetic grain growth equation at temperature 300 ℃. At temperature higher than 400℃ (including 400 ℃), the grain sizes of the samples increase with the pressure increasing from 1 to 6 GPa. ZnO nano-bulks with good quality can be obtained under the specific conditions. 展开更多
关键词 nano-crystals ZnO high temperature and pressure grain EVOLUTION
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Improving the colloidal stability of Cellulose nano-crystals by surface chemical grafting with polyacrylic acid
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作者 Dong Cheng Yangbing Wen +4 位作者 Xingye An Xuhai Zhu Xiaojuan Cheng Linqiang Zheng Joseph E Nasrallah 《Journal of Bioresources and Bioproducts》 EI 2016年第3期114-119,共6页
Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the im... Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the improvement of CNC colloidal stability by surface chemical grafting with polyacrylic acid(PAA)was investigated,and the zeta potential and the charge density of the chemically modified CNC were analyzed.The results showed that an acrylic dosage of 1%(based on the dry weight of CNC)was sufficient to significantly enhance the colloidal stability.CNC,after chemical grafting with PAA,showed better stability against the increase in storage time or solid content of the aqueous medium,compared with the un-modified CNC. 展开更多
关键词 cellulose nano-crystals(CNC) colloidal stability acrylic acid particle size zeta potential charge density
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A novel synthesis method and up-conversion properties of hexagonal-phase NaYF_4:Er nano-crystals 被引量:4
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作者 罗显佳 Ryosuke Yuminami +1 位作者 Takeaki Sakurai Katsuhiro Akimoto 《Journal of Rare Earths》 SCIE EI CAS CSCD 2013年第3期267-270,共4页
A novel synthesis method for hexagonal (]3)ophase NaYF4:Er nano-crystals (NCs) which showed up-conversion (UC) from infrared to visible spectral region was developed. The NaYF4:Er NCs were synthesized in oleie... A novel synthesis method for hexagonal (]3)ophase NaYF4:Er nano-crystals (NCs) which showed up-conversion (UC) from infrared to visible spectral region was developed. The NaYF4:Er NCs were synthesized in oleie acid (OA) and 1-0ctadeeene (ODE) with Y2(COa)3'xH20, Er2(COa)3xH20, Na2CO3 and NH4F as precursors. This proposed method was simple and less toxic compared with generally used method so far. The XRD results showed that the molar ratio of OA/ODE and the temperature were key factors for phase control ofNaYF4:Er NCs. The UC emission spectra were obtained with the emission wavelength at about 980 nm (4111/2--4115/2), 800 nm (41912--415/2), 660 nm (4F912--4115/2) and 540 nm (453/2----4115/2) from Er3+ ions, by excitation wavelength of 1550 nm. The slope values, n, in the pump-power dependence, showed that the emission at 980 and 800 um were generated by 2-step UC and at 660 nm and 540 um were 3-step UC. The optical process for the UC excitation was discussed. 展开更多
关键词 rare earths luminescence UP-CONVERSION nano-crystAL NAYF4
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Krypton ion irradiation-induced amorphization and nano-crystal formation in pyrochlore Lu_2Ti_2O_7 at room temperature 被引量:1
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作者 谢秋荣 张建 +2 位作者 尹东明 郭奇勋 李宁 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第12期426-430,共5页
Polycrystalline pyrochlore Lu2Ti2O7 pellets are irradiated with 600-keV Kr^3+ions up to a fluence of 1.45 ×10^16Kr^3+/cm^2. Irradiation induced structural modifications are examined by using grazing incidence x... Polycrystalline pyrochlore Lu2Ti2O7 pellets are irradiated with 600-keV Kr^3+ions up to a fluence of 1.45 ×10^16Kr^3+/cm^2. Irradiation induced structural modifications are examined by using grazing incidence x-ray diffraction(GIXRD) and cross-sectional transmission electron microscopy(TEM). The GIXRD reveals that amorphous fraction increases with the increase of fluences up to 2 × 10^15Kr^3+/cm^2, and the results are explained with a direct-impact model.However, when the irradiation fluence is higher than 2 × 10^15Kr^3+/cm^2, the amorphous fraction reaches a saturation of-80%. Further TEM observations imply that nano-crystal is formed with a diameter of -10 nm within the irradiation layer at a fluence of 4 × 10^15Kr^3+/cm^2. No full amorphization is achieved even at the highest fluence of 1.45 × 10^16Kr^3+/cm^2(-36 displacement per atom). The high irradiation resistance of pyrochlore Lu2Ti2O7 at higher fluence is explained on the basis of enhanced radiation tolerance of nano-crystal structure. 展开更多
关键词 radiation damage amorphization nano-crystals ceramics
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Storage Characteristics of Nano-Crystal Si Devices Using Different Measurements for MOS Capacitors
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作者 李蔚 张志刚 +3 位作者 梁仁荣 何洋 王柳笛 朱钧 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第8期1169-1172,共4页
The storage characteristics of nano-crystal Si (NC-Si) devices,especially for MOS capacitors,are studied by cross sectional transmission electron microscopy (TEM) and capacitance-voltage (C-V) measurement under ... The storage characteristics of nano-crystal Si (NC-Si) devices,especially for MOS capacitors,are studied by cross sectional transmission electron microscopy (TEM) and capacitance-voltage (C-V) measurement under different conditions,including programming and erasing at different temperatures and gate voltages,as well as using +/-bias-temperature (BT) measurements.Physical mechanisms such as carrier trapping,interface state filling,and temperature related deterioration are revealed.The experimental results demonstrate that the degradation of the program window and threshold voltage (VT) shift at high temperature,large voltage sweep range,and bias applied to sweep voltage is strongly related to the type of majority carriers. 展开更多
关键词 nano-crystAL STORAGE MEASUREMENT
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The Transmission Modes and Losses of the Poled Nano-crystal and Polymer Composite PbTiO_3 / PEK-c Thin-film Waveguides
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作者 任诠 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第1期66-69,共4页
Composite thin films of PbTiO3 nano-crystals and high transparency polymer polyetherketone (PEK-c) for application of non-linear optical devices were prepared by spin coating. The size of PbTiO3 nano-crystals was es... Composite thin films of PbTiO3 nano-crystals and high transparency polymer polyetherketone (PEK-c) for application of non-linear optical devices were prepared by spin coating. The size of PbTiO3 nano-crystals was estimated to be 30-40 nm using a transmission electron microscope. The refractive index and the mode propagation losses at 633 nm were measured using the prism coupling technique and improved photographic technique respectively. They were found to be 1.6545 and 2.00 dB cm^-1 (fundamental mode),respectively. Moreover, it is observed that this loss is increased at higher mode indices. 展开更多
关键词 optical properties nano-crystals thin-film waveguides mode propagation losses
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A METHOD OF PREPARING SPHERICAL NANO-CRYSTAL CELLULOSE WITH MIXED CRYSTALLINE FORMS OF CELLULOSE Ⅰ AND Ⅱ 被引量:12
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作者 Xiao-fang Li En-yong Ding +1 位作者 Guo-kang Li Laboratory of Cellulose and Lignocellulosics Chemistry, Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650 China College of Material Science and Engineering South China University of Technology, Guangzhou 510641, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2001年第3期291-296,共6页
A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our prod... A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are preparedfrom natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose I and II. The preparationconditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products arealso strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, theultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gelpermeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy(TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the panicle. 展开更多
关键词 Spherical nano-crystal cellulose Mixed crystal forms of cellulose and Ultrasonic agitation
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Modified Scherrer Equation to Estimate More Accurately Nano-Crystallite Size Using XRD 被引量:41
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作者 Ahmad Monshi Mohammad Reza Foroughi Mohammad Reza Monshi 《World Journal of Nano Science and Engineering》 2012年第3期154-160,共7页
Scherrer Equation, L=Kλ/β.cosθ, was developed in 1918, to calculate the nano crystallite size (L) by XRD radiation of wavelength λ (nm) from measuring full width at half maximum of peaks (β) in radian located at ... Scherrer Equation, L=Kλ/β.cosθ, was developed in 1918, to calculate the nano crystallite size (L) by XRD radiation of wavelength λ (nm) from measuring full width at half maximum of peaks (β) in radian located at any 2θ in the pattern. Shape factor of K can be 0.62 - 2.08 and is usually taken as about 0.89. But, if all of the peaks of a pattern are going to give a similar value of L, then β.cosθ must be identical. This means that for a typical 5nm crystallite size and λ Cukα1 = 0.15405 nm the peak at 2θ = 170° must be more than ten times wide with respect to the peak at 2θ = 10°, which is never observed. The purpose of modified Scherrer equation given in this paper is to provide a new approach to the kind of using Scherrer equation, so that a least squares technique can be applied to minimize the sources of errors. Modified Scherrer equation plots lnβ against ln(1/cosθ) and obtains the intercept of a least squares line regression, ln=Kλ/L, from which a single value of L is obtained through all of the available peaks. This novel technique is used for a natural Hydroxyapatite (HA) of bovine bone fired at 600°C, 700°C, 900°C and 1100°C from which nano crystallite sizes of 22.8, 35.5, 37.3 and 38.1 nm were respectively obtained and 900°C was selected for biomaterials purposes. These results show that modified Scherrer equation method is promising in nano materials applications and can distinguish between 37.3 and 38.1 nm by using the data from all of the available peaks. 展开更多
关键词 X-Ray DIFFRACTION nano-crystAL Scherrer EQUATION HYDROXYAPATITE
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Characteristic Investigation of Nano-Crystal Hydrogen Storage Alloys
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作者 Xiao Fangming Huang Lili +3 位作者 Tang Renheng Lu Qiyun Peng Neng Wang Ying 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第z1期232-234,共3页
A Ml (NiCoMnA1)5 hydrogen storage alloys was prepared by double-roller rapid quenching.Its microstructure, electrochemically and kinetic characteristic were studied.A uniform crystal phase with CaCu5 structure could b... A Ml (NiCoMnA1)5 hydrogen storage alloys was prepared by double-roller rapid quenching.Its microstructure, electrochemically and kinetic characteristic were studied.A uniform crystal phase with CaCu5 structure could be detected by XRD analyses, whose average grain size is 30 ~ 50 nm and the ratio of c/a of nano-crystal hydrogen storage alloy is larger.The hydrogen absorption/desertion p - C isotherms of alloy show that its fiat-performance is perfect and the magnetic stagnant effect is very little.An simulate cell is used for electrochemical measurement.Electrode is 10C, the capacity decreasing rate via the 450 cycles at 7C is less than 20%. 展开更多
关键词 nano-crystAL hydrogen storage alloys electrochemically characteristic
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Determination of the Nucleation Region Location of Si Nano-Crystal Grains Prepared by Pulsed Laser Ablation through Changing Position of Substrates
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作者 Zechao Deng Qingshan Luo +4 位作者 Ziqiang Hu Xiaolong Zhang Xuecheng Ding Lizhi Chu Yinglong Wang 《Journal of Surface Engineered Materials and Advanced Technology》 2013年第2期133-137,共5页
To determine the nucleation region location of Si nano-crystal grains, pulsed laser ablation of Si target is performed in Ar gas of 10 Pa at room temperature with laser fluence of 4 J/cm2, the substrates are located h... To determine the nucleation region location of Si nano-crystal grains, pulsed laser ablation of Si target is performed in Ar gas of 10 Pa at room temperature with laser fluence of 4 J/cm2, the substrates are located horizontal under ablation spot with different vertical distance. Characteristics of deposited grains are described by scanning electron microscopy, Raman scattering and X-ray diffraction spectra, the results indicate that deposition position on substrates in a certain range is relative to target surface, which changes according to different vertical distance of substrates to ablation spot. Grain size increased?at first and then decreased with addition of lateral distances to target in the range, but the integral distribution rule was independent of position of substrates. Combining with hydrodynamics model, nucleation division model, thermokinetic equation and flat parabolic motion, spatial nucleation region location of grains is obtained through numerical calculations, which is 2.7 mm-43.2 mm to target surface along the plume axis. 展开更多
关键词 NUCLEATION REGION LOCATION SI nano-crystAL Grains Pulsed Laser Ablation
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Diffusion behavior of Ni in Zr_(48)Cu_(36)Ag_8Al_8 bulk metallic glass within supercooled liquid region 被引量:1
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作者 孙琳琳 王军 +3 位作者 寇宏超 唐斌 李金山 张平祥 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1171-1175,共5页
Diffusion behavior of Ni in Zr48Cu36Ag8Al8 metallic glass was investigated in the temperature range of 683-723 K by secondary ion mass spectrum(SIMS) and transmission electron microscope(TEM). The diffusivity of Ni in... Diffusion behavior of Ni in Zr48Cu36Ag8Al8 metallic glass was investigated in the temperature range of 683-723 K by secondary ion mass spectrum(SIMS) and transmission electron microscope(TEM). The diffusivity of Ni in Zr48Cu36Ag8Al8 is reasonably fitted by a single Arrhenius relation with small effective activation energy. The diffusivity of Ni in Zr48Cu36Ag8Al8 is an instantaneous function of annealing time in the supercooled liquid region. In addition, a large number of nano-crystals are detected near the interface of Ni-Zr48Cu36Ag8Al8 diffusion couple, and its width is broader than the Ni diffusion depth determined by SIMS. The results indicate that atomic inter-diffusion is an important factor to promote the formation of nano-crystals within the diffusion zone. 展开更多
关键词 metallic glasses diffusion behavior interface nano-crystAL
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<i>Ab Initio</i>Molecular Orbital Calculation for Optical and Electronic Properties Evaluation of Small and Medium Size Silicon Nano-Clusters Found in Silicon Rich Oxide Films
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作者 Néstor David Espinosa Torres José Francisco Javier Flores Gracia +5 位作者 José Alberto Luna López Juan Carlos Ramírez García Alfredo Morales Sánchez José Luis Sosa Sánchez David Hernández de la Luz Francisco Morales Morales 《Journal of Modern Physics》 2013年第11期1-26,共26页
In systems in atomic and nano scales such as clusters or agglomerates constituted of particles from a few to less than one hundred of atoms, quantum confinement effects are very important. Their optical and electronic... In systems in atomic and nano scales such as clusters or agglomerates constituted of particles from a few to less than one hundred of atoms, quantum confinement effects are very important. Their optical and electronic properties are often dependent on the size of the systems and the way in which the atoms in these clusters are bonded. Generally, these nano-structures display optical and electronic properties significantly different of those found in corresponding bulk materials. Silicon agglomerates found in Silicon Rich Oxide (SRO) films have optical properties, which have reported as depended directly on nano-crystal size. Furthermore, the room temperature photoluminescence (PL) of Silicon Rich Oxides (SRO) has repeatedly generated a huge interest due to their possible applications in optoelectronic devices. However, a plausible emission mechanism has not yet widespread acceptance of the scientific community. In this research, we employed the Density Functional Theory with a functional B3LYP and a basis set 6 - 31G* to calculate the optical and electronic properties of small (six to ten silicon atoms) and medium size clusters of silicon (constituted of eleven to fourteen silicon atoms). With the theoretical calculation of the structural and optical properties of silicon clusters, it is possible to evaluate the contribution of silicon agglomerates in the luminescent emission mechanism experimentally found in thin SRO films. 展开更多
关键词 nano-crystals SILICON Clusters Silicon-Rich Oxide Luminescence Magic-Number
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SYNTHESIS OF Ni-Mo ALLOYS BY MECHANICAL ALLOYING
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作者 LIANG Guoxian WANG Erde HUO Wencan Harbin Institute of Technology,Harbin,China Post Box 435,Harbin Institute of Technology,Harbin 150006,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1993年第12期437-441,共5页
Ni_(100-x)Mo_x(x=20,30,38)alloys have been synthesized by mechanical alloying.The structure evolution of powders in mechanical alloying process has been monitored by X-ray diffraction,scanning electron microscopy and ... Ni_(100-x)Mo_x(x=20,30,38)alloys have been synthesized by mechanical alloying.The structure evolution of powders in mechanical alloying process has been monitored by X-ray diffraction,scanning electron microscopy and transmission electron microscopy analyses.The results show that the Ni_(62)Mo_(38)sample becomes partially amorphous after high energy ball milling,while the Ni_(80)Mo_(20)and Ni_(70)Mo_(30)become non-equilibrium nanocrystals. 展开更多
关键词 mechanical alloying Ni-Mo alloy amorphization nano-crystAL
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Structural and mechanical properties of nano-crystal TiN coatings
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作者 ZHANG Chenhui PAN Guoshun LUO Jianbin LI Wenzhi CHEN Darong 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2004年第z1期1-7,共7页
The structural and mechanical properties of TiN coatings prepared by ion beam assisted deposition (IBAD) were studied. The coatings have a polycrystal structure with grain size of ~10 nm or less. The hardness of the ... The structural and mechanical properties of TiN coatings prepared by ion beam assisted deposition (IBAD) were studied. The coatings have a polycrystal structure with grain size of ~10 nm or less. The hardness of the coatings increases with increasing grain size of TiN crystallites. The coating with grain size of 10.3 nm even has a superhardness of 44.7GPa. The relationship between the hardness and the grain size in the nano-crystalline coatings was discussed on the basis of grain-boundary triple junctions. 展开更多
关键词 TiN nano-crystal microstructure hardness GRAIN-BOUNDARY TRIPLE junctions.
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A novel 2 T P-channel nano-crystal memory for low power/high speed embedded NVM applications
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作者 张君宇 王永 +4 位作者 刘璟 张满红 许中广 霍宗亮 刘明 《Journal of Semiconductors》 EI CAS CSCD 2012年第8期67-70,共4页
We introduce a novel 2 T P-channel nano-crystal memory structure for low power and high speed embedded non-volatile memory(NVM) applications.By using the band-to-band tunneling-induced hot-electron (BTBTIHE) injec... We introduce a novel 2 T P-channel nano-crystal memory structure for low power and high speed embedded non-volatile memory(NVM) applications.By using the band-to-band tunneling-induced hot-electron (BTBTIHE) injection scheme,both high-speed and low power programming can be achieved at the same time. Due to the use of a select transistor,the "erased states" can be set to below 0 V,so that the periphery HV circuit (high-voltage generating and management) and read-out circuit can be simplified.Good memory cell performance has also been achieved,including a fast program/erase(P/E) speed(a 1.15 V memory window under 10μs program pulse),an excellent data retention(only 20%charge loss for 10 years).The data shows that the device has strong potential for future embedded NVM applications. 展开更多
关键词 P-CHANNEL select transistor nano-crystal memory EMBEDDED
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Preparation and luminescence properties of BaWO_4:Yb^(3+)/Tm^(3+) nano-crystal
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作者 贺超 杨魁胜 +1 位作者 刘磊 司振君 《Journal of Rare Earths》 SCIE EI CAS CSCD 2013年第8期790-794,共5页
This research investigated the effect of different contents of Tm3+ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4:yb3+/Tm3+ nano-crystal synthesized by the hydrothermal metho... This research investigated the effect of different contents of Tm3+ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4:yb3+/Tm3+ nano-crystal synthesized by the hydrothermal method. The results indicated that lumines- cence intensity reached the strongest when CTm=1.0 mol.% and Cyb/CTm=2:1. X-ray diffraction revealed the tetragonal system of BaWO4:Yb3+/Tm3+ and the grain sizes were between 31 and 45 nm according to Scherrer equation. The results of X-ray diffraction and scanning electron microscopy were similar. Four emission peaks at 454, 475, 647 and 790 nm including two blue emission peaks and two red emission peaks, corresponding to ID2→3F4, 1G4→3H6, IG4→3F4 and 3H4→3H6 transitions of Tm3+, were observed under excitation of 980 nm semiconductor laser. Blue emissions at 454 and 475 um were four-photon and three-photon absorption respec- tively in accordance with the relationship between luminescence intensity and pump power. 展开更多
关键词 hydrothermal method BaWO4:Yb3+ /Tm3+ nano-crystal UP-CONVERSION rare earths
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纳米晶Ti(CN)基金属陶瓷的研究 被引量:2
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作者 周书助 卓海宇 胡茂中 《硬质合金》 CAS 北大核心 2006年第1期5-7,共3页
对纳米晶Ti(CN)基金属陶瓷进行了初步的研究;与较粗Ti(CN)基金属陶瓷相比,纳米Ti(CN)基金属陶瓷表现更加均匀的球形结构;由于细化的结构和强化的粘结相,纳米结构金属陶瓷具有不同的韧化机理,其断裂韧性要比微米金属陶瓷提高50%。
关键词 Ti(CN) 金属陶瓷 纳米晶 球形结构
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