共查询到18条相似文献,搜索用时 156 毫秒
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本文用固相反应烧结制备出Li2Mo2O6多晶材料。经X射线分析、红外光谱和电子顺磁共振谱(EPR)的研究,确定了它的结构是Li2Mo2O4和MoO2两个晶相组成的烧结体。钼离子以四价状态存在于MoO2晶相结构中。采用交流阻抗谱分析了晶界与温度变化的相关性。测得了样品的ln(σ总T)-1/T 曲线是由两段直线和一段曲线所组成;总电导率化能σ27℃=1.36×10-3(Ω·cm)-1,σ115℃=1.49×10-3(Ω·cm)-1,σ300℃=9.71×10-3(Ω·cm)-1,σ370℃=2.42×10-3(Ω·cm)-1;电导活化能E1=0.043eV,E2=0.235eV,E平均=0.76eV。采用维格纳极化电池法测得电子电导率σe,σe27℃=2.240×10-5(Ω·cm)-1,σe300℃=4.476×10-3(Ω·cm)-1。实验证明,室温下材料为固体电解质,300℃附近为良好的离子与电子混合导体。
关键词: 相似文献
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用最小偏向角法在20℃下精确测量了0.62Pb(Mg1/3Nb2/3)O3< /sub>-0.38PbTiO3( 0.62PMN-0.38PT)单晶的折射率,给出了该温度下折射率色散的Sellmeier方程.研究了能带 结构与折射率的关系,计算了样品的Sellmeier光学系数:对no,E0=5.50eV,λ0=0.2 26μm,S0=1.004×1014m-2,Ed=28.1 0eV;对ne,E0=5.57eV,λ 0=0.223μm,S0=1.017×1014m-2,Ed=28.10eV.A BO3型钙钛矿材料中,BO6八面体基元决定了晶体的能带结构,对折 射率产生重要影响.
关键词:
PMNT单晶
折射率
Sellmeier光学系数 相似文献
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本文研究了Lisicon(锗酸锌锂)单晶的Li+离子电导率。发现各结晶学方向电导率之间的关系为σb≤σa≤σc≤σ[110],但各向异性不强。晶体中Li含量对电导率有明显的影响,当Li/Zn比率由6.7变到9.2时,300℃a方向电导率由4.3×10-2Ω-1·cm-1增加到1.25×10-1Ω-1·cm-1,logσT对1/T的曲线显示出三个转变点,分别在~80℃,~140℃和~300℃。电导的激活能分别为0.50—0.58eV(25—80℃),0.92eV(~80—140℃),0.64eV(~140—300℃)和0.36eV(>300℃),极化实验表明单晶的电子电导可以忽略。
关键词: 相似文献
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通过两步固相反应烧结法制备了(1-x)Pb0.99Nb0.02[(Zr0.57Sn0.43)0.94Ti0.06]0.98O3:xAlN ((1-x)PNZST:xAlN,x=0,0.1,0.2,0.3,0.4))复合陶瓷,系统研究了复合陶瓷晶体结构、微观形貌、畴结构演变以及铁电、介电和热释电性能等.实验结果表明:基于两相之间热膨胀系数失配产生的局域应力场有效调控了畴结构组态和相结构演变,在室温附近构建了铁电/反铁电相界,继而在温度场作用下表现出优异的热释电性能;当x=0.1时,在近人体温度37℃时其热释电系数p达到最大值3.30×10-3 C/(m2·K),电流响应优值Fi=3.16×10-9 m/V,电压响应优值Fv=0.613 m2/C,探测率优值Fd=4... 相似文献
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采用Czochralski 法生长出光学质量的BaWO4:Tm3+单晶,利用X粉末衍射实验确定了不同掺杂浓度晶体的晶胞参数.测定了晶体的室温吸收光谱,应用Juud-Ofelt理论,拟合了光谱的3个强度参数,其值分别为Ω2=404×10-20cm2,Ω4=0509×10-20cm2,Ω关键词:
4:Tm3+单晶')" href="#">BaWO4:Tm3+单晶
吸收谱
光谱参数
上转换发光 相似文献
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本文采用由自由核子,α粒子及平均重核组成的核统计平衡模型描述由自由核子和许多种类原子核组成的系铣。由半径验核质量及核激发态熵公式描述核的性质,给定系统温度、密度及电子浓度ye,由系统自由能在电中性及强子数守恒约束下求极小得我们的物态方程EOS(Ⅰ),并与E1 Eid等物态方程(在密度ρ~109-1012g cm-3)和与Lgmb等物态方程(在ρ~1012-1014g cm-3,ye=0.3,σ=1.5k)作了比较,符合程度较好。本文对电子俘获率也作了更细致的考虑。 相似文献
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研究了一种新型掺Er3+碲酸盐玻璃的光谱性质;应用Judd-Ofelt理论计算了碲 酸盐玻璃中Er3+离子的强度参数Ω(Ω2=479×10-20 cm2,Ω4= 152×10-20cm2,Ω6=066×10-20cm2),计算了离子的自发跃迁概 率,荧光分支比;应用McCumber理论计算了Er3+的受激发射截面(σe=1040×1 0-21cm2),Er3+离子4I13/ 2→4I15/2发射谱的 荧光半高宽(FWHM=655nm)及各能级的荧光寿命(4I13/2 能级为τrad =399ms);比较了不同基质玻璃以及不同类型碲酸盐玻璃中Er3+离子的光谱 特性, 结果表明该掺铒碲酸盐玻璃具有更好的光谱性能,更适合于掺Er3+光纤放大 器实现宽带和高增益放大.
关键词:
碲酸盐玻璃
光谱性质
Judd-Ofelt理论 相似文献
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M. Luennemann U. Hartwig G. Panotopoulos K. Buse 《Applied physics. B, Lasers and optics》2003,76(4):403-406
The electrooptic effect in lithium niobate crystals (LiNbO3) for extremely high externally applied electric fields of up to 65 kV/mm is investigated. Homogeneous electrooptic refractive-index
changes of up to 4.8×10-3 are found for ordinarily polarized light. No quadratic electrooptic effect is observed. An upper bound for the quadratic
electrooptic coefficient of |s13|≤2.3×10-21 m2/V2 is determined. Electrooptic, angular, and wavelength tuning of the Bragg condition of a thermally fixed hologram are demonstrated.
Received: 29 October 2002 / Revised version: 14 January 2003 / Published online: 26 March 2003
RID="*"
ID="*"Corresponding author. E-mail: ml@uni-bonn.de 相似文献
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R.A. Graham 《Solid State Communications》1973,12(6):503-506
Measurements of the piezoelectric polarization of z-cut lithium niobate are accomplished for dynamic compressive strains of from 8.9 × 10?4 to 6 × 10?3. Values for the linear piezoelectric constant, 33 and its strain derivative are determined. The logarithmic strain derivatives of the longitudinal piezoelectric constants of x-cut quartz and z-cut lithium niobate are found to be approximately equal. 相似文献
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H. Tian Z. Zhou D. Gong H. Wang D. Liu Y. Jiang 《Applied physics. B, Lasers and optics》2008,91(1):75-78
We report the successful growth of an electroholographic crystal, potassium sodium tantalate niobate (KNTN), by a top-seeded
solution growth method. Both blue and colorless crystals were obtained. The structure, optical absorption, and refractive
dispersion properties of the as-grown crystals have been investigated. Furthermore, the Kerr coefficients R11 and R12 of paraelectric K0.95Na0.05Ta0.61Nb0.39O3 single crystal were determined by using an automated scanning Mach–Zehnder interferometer. The crystal has large Kerr coefficients
with R11= 2.8×10-16 m2/V2 and R12= -0.3×10-16 m2/V2 at the wavelength of 632.8 nm near its cubic–tetragonal phase boundary.
PACS 81.10.Dn; 42.70.Nq 相似文献
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采用飞片碰撞技术,在TNT/RDX(40/60)炸药中获得了2.5倍于正常爆轰的最大超压值,得到了超压爆轰下爆轰产物物态方程p=Aρk+A1(p-pJ)(p-爆压,单位GPa,ρ-密度,单位kg/m3,A=ρJ/ρkJ,pJ=27.06 GPa,ρJ=2.3×103 kg/m3,k=2.77,A1=2.7×10-3 GPa-1,下表J代表正常爆轰状态)。该方程还可以较好地描述超压爆轰产物的二次冲击状态。 相似文献
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We have measured the propagation velocities of bulk acoustic waves in the simple cubic transition-metal oxide ReO3 by ultrasonic pulse propagation. The elastic stiffness constants at 300 K are: C11 = (47.9 ± 1.4) × 1011 dyne/cm2; C44 = (6.1 ± 0.2) × 1011 dyne/cm2; C12 = (?0.7 ± 2.8) × 1011 dyne/cm2. These elastic constants indicate a crystal with highly anisotropic shear propagation. The Debye temperature of the compound from these measurements is 528 K. This value is somewhat higher than previous results from specific heat and resistivity determinations. 相似文献
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Thermo-electric method for nearly complete oxidization of highly iron-doped lithium niobate crystals
A new method is presented, allowing the nearly complete oxidization of lithium niobate crystals (LiNbO3), doped with large amounts of iron oxide (0.05–3 wt. % Fe2O3) utilizing annealing at 700 °C in the presence of externally applied electric fields. The treatment results in a concentration
ratio of Fe2+ and Fe3+ ions of less than 2×10-3. Strong oxidization of iron in LiNbO3 reduces the photorefractive effect and is therefore of particular interest for nonlinear-optical applications.
PACS 42.65.-k; 66.30.Hs; 71.55.-i 相似文献