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1.
利用电弧炉熔炼法分别制备了LaFe11.2Co0.7Si1.1B0.2,LaFe11.1Co0.8Si1.1B0.2和LaFe11Co0.9Si1.1B0.2化合物。磁性测量和计算得到该系列化合物的等温磁熵变,利用直接测量法测量该系列化合物在外加磁场为0-1.5T下的绝热温变。最后分别计算基于等温磁熵变和绝热温变的相对制冷能力。 相似文献
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李福安 《黄山高等专科学校学报》2014,(3):13-16
利用电弧炉熔炼法分别制备了LaFe11.2Co0.7Si1.1B0.2,LaFe11.1Co0.8Si.iB0.2和LaFe11Co0.9Si1.1B0.2化合物.磁性测量和计算得到该系列化合物的等温磁熵变,利用直接测量法测量该系列化合物在外加磁场为0-1.5T下的绝热温变.最后分别计算基于等温磁熵变和绝热温变的相对制冷能力. 相似文献
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金属La部分取代MI（混合稀土）的贮氢合金电极Ml0.8La0.2Ni4.0Mn0.4Co0.4Al0.1（A）容易活化，其充电效率、放电容量、快速放电能力以及荷电保持能力比电极MlNi4.0Mn0.4Co0.4Al0.1（B）分别提高5．5％、7．0％、4．0％和8．2％。电极A放电过电位比电极增大，且循环稳定性下降。 相似文献
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金属La部分取代M l(混合稀土)的贮氢合金电极M l0.8La0.2N i4.0Mn0.4Co0.4A l0.1(A)容易活化,其充电效率、放电容量、快速放电能力以及荷电保持能力比电极M lN i4.0Mn0.4Co0.4A l0.1(B)分别提高5.5%、7.0%、4.0%和8.2%。电极A放电过电位比电极增大,且循环稳定性下降。 相似文献
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《宜宾学院学报》2016,(6):86-90
利用基于密度泛函理论的第一性原理方法对未掺杂的锶铁氧体SrFe_(12)O_(19)、Co掺杂SrFe_(12)O_(19)及Co与Nd共掺杂SrFe_(12)O_(19)的晶体结构、电子性质及磁性性质进行了计算.结果表明:未掺杂的SrFe_(12)O_(19)晶体为半导体,体系中Fe原子表现为高自旋态,2a、2b、12k晶位Fe原子的磁矩与4f1、4f2晶位Fe原子的磁矩反平行排列,总磁矩为40μB;Co掺杂SrFe_(12)O_(19)后体系表现出金属性,Co与Fe原子均表现出高自旋态,Co原子磁矩为2.5μB,Fe原子磁矩为3.58μB,总磁矩为34μB;Co与Nd共掺杂SrFe_(12)O_(19)后Fe原子表现为高自旋态,磁矩为3.55μB,Nd原子被局域为高自旋态,磁矩为3μB,Co原子表现为低自旋态,体系总磁矩为62μB,掺杂后体系磁性明显增强. 相似文献
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李彤 《天津工程师范学院学报》2009,19(3)
采用磁控溅射法在Si衬底上通过改变沉积顺序制备两类异质PN结:La0.8Sr0.2MnO3/TiO2和TiO2/La0.8Sr0.2MnO3,并时其进行电学性能研究.结果显示Si/La0.8Sr0.2MnO3/TiO2异质PN结中的Ⅰ-Ⅴ特性曲线呈现线性特征.这可能是TiO2薄膜区内垂直于生长界面的缺陷使得在垂直于衬底方向上产生载流子"通道",从而导致没有整流特性.而在Si/TiO2/La0.8Sr0.2MnO3异质PN结中的Ⅰ-Ⅴ特性曲线却呈现良好的整流特性.这可能是La0.8Sr0.2MnO3和TiO2生长的均很致密,没有给电流提供导通通道,使得呈现明显整流特性.变温电流电压特性曲线显示整流特性出现在一个50 K到350 K广泛温区,与此同时,随着测量温度的降低,扩散电压增大,这可能由于随着测量温度的变化导致了界面电子结构的变化. 相似文献
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研究了用桑色素的氧化来显色测定Co2++H2O2体系产生羟自由基(·OH)的方法,提出Co2++H2O2桑色素分析新体系并用于羟自由基(·OH)的测定.本方法利用Co2+与H2O2反应,类似Fenton试剂产生羟自由基(·OH),所产生的羟自由基与桑色素作用后使其吸光度降低,利用吸光度值的变化可间接测定所产生的羟自由基,确定了体系最佳实验条件.同时测定抗氧化剂清除羟自由基的实验,证明该体系可作为筛选抗氧化剂的方法之一. 相似文献
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以开发固体氧化物燃料电池（SOFC）新型阴极材料为目的,采用高温固相反应法合成了一系列钙钛矿型复合氧化物La0.8Sr0．2Mn1-yCOyO3-δ（LSMC,Y分别取0.3,0．5和0．7）,并对Mn位掺杂不同量过渡族元素Co后样品的高温电导率和热膨胀系数进行了研究,发现随着Co含量的增加,材料的电导率和热膨胀系数均增大,其中La0.8Sr0．2Mn0.3Co0.7O3-δ的电导率最高,700℃时,达270．89S·cm^-1。 相似文献
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采取三种方法合成了镍钴酸锂电极材料Lia Ni0.7Co0.3O2,用电化学实验方法研究了合成方法对材料的电化学性能的影响,材料用XRD表征.结果表明:通过预处理后合成的电极材料具有较好的电化学性能,首次充放电比容量可达到196.5和167.9 mAh·g-1. 相似文献
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WANG Xiu-li TU Jiang-ping CHEN Chang-pin ZHANG Xiao-bin ZHAO Xin-bing 《Journal of Zhejiang University. Science. B》2005,(3)
Mg2Ni0.8Cr0.2-x wt.% CoO/Al2O3 (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg2Ni0.8Cr0.2 alloy and CoO/Al2O3 compound for 45 h. The addition of CoO/Al2O3 compound resulted in the good kinetics properties of hydriding/dehydriding reaction of the composites. The composite with 1.0 wt.% CoO/Al2O3 catalyst could reach the maximum hydrogen absorption capacity (2.9 wt.%) within 5 min at 393 K under H2 pressure of 4 MPa, and can desorb rapidly at 493 K. The decomposition and synthesis of hydrogen molecule on Mg2Ni0.8Cr0.2 alloy surface was promoted by addition of CoO/Al2O3 catalyst. In addition, the formation of metallic Ni particles, strain and defects during the ball milling process also resulted in the improved hydrogenation performance of Mg2Ni-based alloys. 相似文献
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Wang XL Tu JP Chen CP Zhang XB Zhao XB 《Journal of Zhejiang University. Science. B》2005,6(3):208-212
INTRODUCTION Mg-based alloys are considered as potentialcandidates for hydrogen storage materials because oftheir large hydrogen capacity (Reilly and Wiswall,1968; Pedersen and Larsen, 1993). However, asMg-based alloys desorb hydrogen at temperatureshigher than 600 K, they are not applicable to practicaluse. Many researches have studied to improve hy-driding/dehydriding kinetics and to lower the workingtemperature (Wang et al., 2002; Tsushio et al., 1998;Spassov and K?ster, 1998; Orim… 相似文献
14.
Different ambient conditions for the synthesis of Ag（Nb0.8Ta0.2）O3 ceramics were investi- gated. The Ag（Nb0.8Ta0.2）O3 powder was synthesized at 950 ℃ under different ambient conditions, and then pressed into disks and sintered between 1060 ℃ and 1100 ℃ respectively. Samples were investigated by X-ray diffraction, scanning electron microscopy and dielectric measurement. The results show that perovskite Ag（Nb0.8Ta0.2）O3 powder was easier to be synthesized in air than in vacuum at 950℃. Grain size of ceramic samples sintered in air was uniform （about 1 μm） and its dielectric loss was small for its high density. However, the samples decomposed greatly and ceramics could hardly be densified when sintered in vacuum, Thus,. higher atmospheric pressure and oxygen atmosphere would benifit the synthesis of Ag （Nb0.8Ta0.2）O3, and suppress its decomposition at high temperature. 相似文献
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INTRODUCTION Liquid crystal light valves (LCLV) are devices whose function is to convert an input image pos-sessing specific wavelength, intensity and coher-ence to an output image in which some or all of these parameters are varied (Efron et al., 1985). Therefore, they can be used as image amplifiers for large screen projection display, image wavelength converters and incoherent-to-coherent image converters for optical data processing and correlation. The appli-cation potentialities ar… 相似文献
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The structural characteristics and optical and electrical properties of molecular-beam-epitaxy (MBE) grown ZnS0.8Se0.2 thin films on indium-tin-oxide (ITO) glass substrates were investigated in this work. The X-ray diffraction (XRD)results indicated that high quality polycrystalline ZnS0.8Se0.2 thin film grown at the optimized temperature had a preferred orientation along the (111) planes. The transmission electron microscopy (TEM) cross-sectional micrograph of the sample showed a well defined columnar structure with lateral crystal dimension in the order ofa few hundred angstroms. Ultraviolet (UV) photoresponsivity as high as 0.01 A/W had been demonstrated and for wavelengths longer than 450 nm, the response was down from the peak response by more than 3 orders of magnitude. The thin ZnS0.8Se0.2 photosensor layer, with a wide energy gap and anisotropic electrical property, makes a transmission UV liquid crystal light valve ( LCLV) with high resolution feasible. 相似文献
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The structural characteristics and optical and electrical properties of molecular-beam-epitaxy (MBE) grown ZnS0.8Se0.2 thin films on indium-tin-oxide(ITO) glas substrates were investigated in this work. TheX-ray diffraction (XRD) results indicated that high quality polycrystalline ZnS0.8Se0.2 thin film grown at the optimized temperature had a prefered orientation along the (111) planes. The transmission electron
microscopy (TEM) cross-sectional micrograph of the sample showed a well defined columnar structure with lateral crystal dimension
in the order of a few hundred angstroms. Ultraviolet (UV) photoresponsivity as high as 0.01 A/W had been demonstrated and
for wavelengths longer than 450 nm, the response was down from the peak response by more than 3 orders of magnitude. The thin
ZnS0.8Se0.2 photosensor layer, with a wide energy gap and anisotropic electrical property, makes a transmission UV liquid crystal light
valve (LCLV) with high resolution feasible.
Project supported by the National Natural Science Foundation of China (No. 59910161981) and RGC grant from the Hong Kong Government
Grant (No. NSFC/HKUST 35), China 相似文献
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Li Y Luo ZY Yu CJ Luo D Xu ZA Cen KF 《Journal of Zhejiang University. Science. B》2005,6(11):1124-1129
INTRODUCTION The solid oxide fuel cell (SOFC) has attracted much attention as a promising source of electrical power generation because of its high efficiency in converting chemical energy to electrical power. De- velopment of SOFC with operating temperature of less than 800 °C has been extensively studied. SOFC has the potential to have the cost of its materials, cell fabrication, and corrosion of its stack components dramatically reduced. Gadolinia-doped ceria with the chemical fo… 相似文献
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NixZn1-xFe2O4铁氧体具有高频中低损耗的特点,通过提高Ni含量至0.8降低起始磁导率,增加截止频率,应用于更高频率。通过固相反应法合成了Ni0.8Zn0.2Fe2O4,并测定了铁氧体样品在低频低磁通密度下的损耗特性,讨论了烧结温度对损耗的影响。 相似文献