共查询到20条相似文献,搜索用时 93 毫秒
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探讨了利用普通光谱型椭偏仪对各向异性液晶层进行综合性测量的可行性. 并利用法国Jobin Yvon公司的UVISEL SPME(Spectroscopic Phase Modulated Ellipsometer)光谱型椭偏仪测量了光学各向异性液晶层的折射率no和ne及液晶层厚d,进一步利用椭偏仪在透射方式下测量了平行排列液晶层的光延迟特性Δnd,二者取得了很好的一致性,说明利用光谱型椭偏仪可以实现对光学单轴性液晶层及其他材料的测量,测厚精度为纳米量级.
关键词:
光谱型椭偏仪
各向异性
折射率
相位延迟 相似文献
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讨论了把单长TP-77型随偏仪改装成椭偏光谱仪的原理,并用改装后的椭偏仪测量多个波长下GaAs的光学参量,测量结果与参考文献的结果符合较好,改进后的实验提高了学生的动手能力,加深了学生对椭偏技术的了解。 相似文献
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利用KNSBN掺Cu晶体实现了自泵浦位相共轭;掺Cu量0.04wt%的晶体自泵浦位相共轭反射率高达65%;测量了自泵浦位相共轭反射率,响应时间和氩离子激光波长的关系。 相似文献
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通过数值计算,研究了强短波(400—600 nm)激光场中H2+分子高次谐波辐射的椭偏率性质.研究表明,H2+分子在不同激光强度、不同激光波长、不同核间距及不同取向角下高次谐波的椭偏率性质是不同的;特别是在两中心干涉区,激发态在高次谐波产生中起着重要作用,但在不同取向角下,激发态对谐波椭偏率的影响不同;分析表明,这些不同的影响源于沿平行和垂直于激光偏振方向辐射的高次谐波的相对产量,以及激发态对平行和垂直谐波产量的影响;此外,椭偏率的测量检验了强场近似和平面波近似在强短波激光场中是成立的,并对强短波激光场中分子动力学做了更充分的研究. 相似文献
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本文提出了予测稠苯芳杂环及其烷基链上质子化学位移的计算方法。
将稠苯芳杂环化合物用凯库勒式表示,计算式为为需考虑的苯环内的乙烯基效应。σmi,ci为各苯环的环流效应。σ1,Hc为各芳杂环的屏蔽效应,对杂环上质子它就是该单独芳杂环上相应质子的δ值,对苯环上质子要将它分解为各结构因素的效应,即:σ1,He=(1/2)d-1δx=y(或σz)+σc-c·σm,H.
σx-y与σz为杂原子或其基团的屏蔽效应,σc=c为存在于芳杂环中的乙烯基的效应,σm,Hc为芳杂环的环流效应,d为对不同质子所考虑的键数。有取代基时需考虑取代基的效应。计算环上烷基质子的公式为:δ=σp,CH3+ασc,CH3+βσt,CH3+σl,G
σl,G为稠苯芳杂环基的某级效应。 相似文献
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Shuji Hasegawa Yasuyoshi Nagai Toshio Oonishi Nobuhiko Kobayashi Takashi Miyake Shuuichi Murakami 《Phase Transitions》2013,86(2-4):87-114
Structural phase transitions between various kinds of superlattice structures formed on a Si(111) surface have been investigated by spot analysis of reflection high-energy electron diffraction (RHEED). Reversible transitions induced by temperature changes and irreversible ones induced by metal depositions were observed. Detailed discussions on the dynamics of the phase transitions are made by quantitative analyses of integrated spot intensity and profile. For a phase transition of 7′7 1′1 structures on a clean Si(111) surface, a hysteresis with temperature difference of 5°C. between in heating and cooling processes was found in the spot intensity change, indicating a first-order transition. Hysteresis was hardly recognized, on the other hand, for transitions of Au-induced superstructures (5×2-Au or ×-Au) 1×1-Au. The spot profiles were found to be broadened during the transition of Si(111)-×-Au 1×1-Au, which was a signature of a continuous transition, while the profiles remained unchanged during the transitions of the 7×7 1×1 and 5×2-Au 1×1-Au phases. Structural conversions induced by In adsorption on the Si(111) surface kept at constant temperatures were also analyzed. The conversions at room temperature were totally dependent on the initial substrate surface structures; the 7×7 surface did not show any structural conversion with In adsorption, while the ×-In surface successively converted to a 2×2 and a × phase with coverage increase. The structural transitions at elevated temperatures were sensitively dependent on the temperatures. Sequences of transitions among the 7×7, 4×1, ×, 1×, and ×4 were quantitatively revealed as changes in RHEED spot intensity. 相似文献
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研究了Er1.0P5O14铒非晶玻璃的红外量子剪裁现象. 从吸收谱和激发光谱的计算比较中肯定了Er1.0P5O14非晶 玻璃的1537.0 nm红外荧光为多光子量子剪裁荧光. 从Er1.0P5O14非晶玻璃的可见和红外荧光发射光谱中发现激发2H11/2, 4G11/2和4G9/2能级所导致的4I13/2→4I15/2量子剪裁红外荧光很强;基于自发辐射速率、无辐射弛豫速率和能量传递速率等参数的计算,对其量子剪裁机理进行了分析.发现起源于基态的强下转换能量传递{2H11/2→4I9/2,4I15/2→4I13/2},{4G11/2→4I13/2, 4I15/2→2H11/2},{4G9/2→4F7/2,4I15/2→4I13/2}和{4G9/2→4I13/2, 4I15/2→2H11/2}是导致Er1.0P5O14非晶玻璃具有强的三光子和四光子量子剪裁红外荧光的原因.研究结果对改善太阳能电池效率有一定意义. 相似文献
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Helga Baum 《Journal of Geometry and Physics》1987,4(4):503-522
Let
(P) be the moduli space of irreducible connections of a G-principal bundle P over a closed Riemannian spin manifold M. Let DA be the Dirac operator of M coupled to a connection A of P and f a smooth function on M. We consider a smooth variation A(u) of A with tangent vector ω and denote Tω:=
(DA(u)−f) (u=0. The coefficients of the asymptotic expansion of trace (Tω · e-t(DA−f)2) near t=0 define 1-forms a(k)f, K=0, 1, 2, … on
(P). In this paper we calculate aa(0)f, a(1)f, a(2)f and study some of their properties. For instance using the 1-form a(2)f for suitable functions f we obtain a foliation of codimension 5 of the space of G-instantons of S4. 相似文献
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An attempt is made to synthesize Nd2Co14C compound by mechanical alloying Nd16Co76B8−xCx (0x8) alloys and subsequent annealing. Phase formation and magnetic properties of Nd2Fe14B-type Nd16Co76B8−xCx alloys and their hydrides are investigated. The Nd2Co14(B,C) phase with Nd2Fe14B-type structure is formed for Nd16Co76B8−xCx (0x7) alloys, while NdCo7Cδ phase with TbCu7-type structure is observed in Nd16Co76C8 alloy. The lattice parameter c of the Nd2Co14(B,C) phase decreases with increasing the carbon content. A limit volume of the unit cell to form the Nd2Fe14B-type structure is estimated to be 0.870 nm3. The spin-reorientation temperature TSR increases with increasing the carbon content, due to an enhancement of magnetocrystalline anisotropy caused by carbon substitution for boron. After hydrogenation, the lattice expansion is observed for Nd16Co76B8−xCx (0x7) alloys. The spin-reorientation temperature of Nd16Co76B8−xCxHy (0x7) is much lower than that of the host alloys. Some structural and magnetic properties of hypothetic Nd2Co14C and Nd2Co14CHy compounds are estimated by extrapolation. 相似文献