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991.
Low-threshold, high-efficiency, high-repetition-rate optical parametric generator based on periodically poled LiNbO3 下载免费PDF全文
We report a high-repetition-rate optical parametric generator (OPG) with a periodically poled lithium niobate (PPLN) crystal pumped by an acousto-optically Q-switched CW-diode-end-pumped Nd:YVO_4 laser. For the maximum 1064nm pump power of 970mW, the maximum conversion efficiency is 32.9% under the conditions of 250℃, 1064nm pulse repetition rate of 22.6kHz and pulse width of 12ns, and the PPLN OPG threshold in the collinear case is less than 23.7μJ. The output power increases with the increase of the crystal temperature. The 1485-1553nm signal wave and 3383-3754nm idler wave are obtained by changing the temperature and the angle of the PPLN crystal. 相似文献
992.
F. Despa R. S. Berry 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):37-40
Interpretive theoretical tools prove valuable in guiding
the analysis of experiments in the realm of atomic clusters.
Here, we review basic elements of an analytic approach that
makes it possible to find and visualize the effective
electrostatic potential and Coulomb correlations in multicenter
problems. To illustrate the utility of these concepts we apply
them to exploring molecular-doped metallic clusters. This study
is aiming at a systematic, visual assessment of changes induced
in screening, Coulomb correlation and effective potential by
varying the charge of the electronegative impurity and its
position in the cluster cage. 相似文献
993.
An O-bonded sulphito complex, Rh(OH2)5(OSO2H)2+, is reversibly formed in the stoppedflow time scale when Rh(OH2)
6
3+
and SO2/HSO
3
−
buffer (1 <pH< 3) are allowed to react. For Rh(OH2)5OH2++ SO2 □ Rh(OH2)5(OSO2H)2+ (k1/k-1), k1 = (2.2 ±0.2) × 103 dm3 mol−1 s−1, k−1 = 0.58 ±0.16 s−1 (25°C,I = 0.5 mol dm−3). The protonated O-sulphito complex is a moderate acid (K
d
= 3 × 10−4 mol dm−3, 25°C, I= 0.5 mol dm−3). This complex undergoes (O, O) chelation by the bound bisulphite withk= 1.4 × 10−3 s−1 (31°C) to Rh(OH2)4(O2SO)+ and the chelated sulphito complex takes up another HSO
3
−
in a fast equilibrium step to yield Rh(OH2)3(O2SO)(OSO2H) which further undergoes intramolecular ligand isomerisation to the S-bonded sulphito complex: Rh(OH2)3(O2SO)(OSO2)- → Rh(OH2)3(O2SO)(SO3)− (k
iso
= 3 × 10−4 s−1, 31°C). A dinuclear (μ-O, O) sulphite-bridged complex, Na4[Rh2(μ-OH)2(OH)2(μ-OS(O)O)(O2SO)(SO3) (OH2)]5H2O with (O, O) chelated and S-bonded sulphites has been isolated and characterized. This complex is sparingly soluble in water
and most organic solvents and very stable to acid-catalysed decomposition 相似文献
994.
Alick KT Law Deepak Gupta Shawn Levy Douglas C Wallace Robert J McKeon Charles R Buck 《BMC neuroscience》2004,5(1):1
Background
The adenine nucleotide translocator 1 (Ant1) is an inner mitochondrial membrane protein involved with energy mobilization during oxidative phosphorylation. We recently showed that rodent Ant1 is upregulated by transforming growth factor-beta (TGF-β) in reactive astrocytes following CNS injury. In the present study, we describe the molecular mechanisms by which TGF-β1 regulates Ant1 gene expression in cultured primary rodent astrocytes. 相似文献995.
不锈钢丝网上薄膜TiO2光催化剂的Raman光谱研究 总被引:1,自引:0,他引:1
用Raman光谱方法来研究用Sol Gel法负载于金属丝网的薄膜TiO2 光催化剂的物相结构、厚度以及粒径大小。研究结果显示 ,薄膜达到一定厚度能够阻止基底Fe元素向薄膜表层的扩散 ;在 4 0 0℃下灼烧制得的薄膜TiO2 光催化剂具有锐钛矿晶型 ,而高于 4 0 0℃时 ,将出现金红石相TiO2 ;锐钛矿晶型TiO2 的Raman特征峰产生偏移 ,表明薄膜粒径的变化 ,通过计算表明 ,薄膜TiO2 的粒径为 10nm左右 ,TEM的分析结果也与之一致。 相似文献
996.
Y.-D Feng Y.-S. Wang Z.-M. Zhang 《Archive of Applied Mechanics (Ingenieur Archiv)》2003,73(5-6):337-347
Summary A 2D time-domain Boundary Element Method (BEM) is applied to solve the problem of transient scattering of plane waves by an inclusion with a unilateral smooth contact interface. The incident wave is assumed strong enough so that localized separations take place along the interface. The present problem is indeed a nonlinear boundary value problem since the mixed boundary conditions involve unknown intervals (separation and contact regions). In order to determine the unknown intervals, an iterative technique is developed. As an example, we consider the scattering of plane waves by the cross section of a circular cylinder embedded in an infinite solid. Numerical results for the near field solutions are presented. The distortion of the response waves and the variation of the interface states are discussed.
The financial support by the China National Natural Science Foundation under Grant No. 19872001 and No. 59878004 is gratefully acknowledged. The second author is also grateful to the support of the National Science Fund for Distinguished Young Scholars under Grant No. 10025211. 相似文献
997.
Mechanisms of the self-organization of nanosystems at the condensation of the extremely weak steady flows of copper vapors
obtained in magnetron sputtering in an ultrapure argon are studied. It is shown that the free-energy minimization near equilibrium
condensation creates prerequisites for the self-organization of statistically homogeneous layers of nanoclusters and determines
the transition to the formation of nanosystems in the form of fractal networks.
Original Russian Text ? V.I. Perekrestov, A.S. Kornyushchenko, Yu.A. Kosminskaya, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ
i Teoreticheskoĭ Fiziki, 2007, Vol. 86, No. 12, pp. 879–883. 相似文献
998.
S. A. Klimin M. N. Popova E. P. Chukalina B. Z. Malkin A. R. Zakirov E. Antic-Fidancev Ph. Goldner P. Aschehoug G. Dhalenne 《Physics of the Solid State》2005,47(8):1425-1430
The absorption spectra of Yb2Ti2O7 single crystals and the luminescence and luminescence excitation spectra of Y2Ti2O7: Yb (1%) polycrystals were studied in the temperature range 4.2–300 K. The spectra were analyzed in terms of the crystal-field
theory and the exchange-charge model. Based on the set of crystal-field parameters found for Yb2Ti2O7, analogous sets of parameters were determined for other rare-earth titanates and proved to be in reasonable agreement with
all available experimental data.
__________
Translated from Fizika Tverdogo Tela, Vol. 47, No. 8, 2005, pp. 1376–1380.
Original Russian Text Copyright ? 2005 by Klimin, Popova, Chukalina, Malkin, Zakirov, Antic-Fidancev, Goldner, Aschehoug,
Dhalenne. 相似文献
999.
In the paper we obtain vector-valued inequalities for Calder6n-Zygmund operator, simply CZO on Herz space and weak Herz space. In particular.we obtain vector-valued inequalities for CZO on Lq(Rd, |x|αdμ) space, with 1< q <∞, -n <α< n(q -1), and on L1,∞(Rd,|x|αdμ) space, with -n <α< 0. 相似文献
1000.