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991.
We consider the stabilization of the transmission problem of Naghdi's model by boundary feedbacks where the model has a middle surface of any shape. The exponential decay rate for the problem is established under some checkable geometric conditions on the middle surface. 相似文献
992.
A new PVC membrane mercury(II) ion electrode based on N,N-dimethylformamide-salicylacylhydrazone (DMFAS) as an ionophore is described, which shows excellent potentiometric response characteristics and displays a linear log[Hg(2+)] versus EMF response over a wide concentration range between 6.2 x 10(-7) and 8.0 x 10(-2) M with a Nerstian slope of 29.6 mV per decade and a detection limit of 5.0 x 10(-7) M. The response time for the electrode is less than 30 s and the electrode can be used for more than 2 months with less than a 2 mV observed divergence in a potentials. The proposed electrode exhibits very good selectivity for mercury(II) ions over many cations in a wide pH range (pH 1 - 4). The electrode was also applied to the determination of a mercury(II) ion in vegetables and in Azolla filiculoides. 相似文献
993.
Xiaochang Ni Ching-yue Wang Li Yang Jianping Li Lu Chai Wei Jia Ruobing Zhang Zhigang Zhang 《Applied Surface Science》2006,253(3):1616-1619
Ablation process of 1 kHz rate femtosecond lasers (pulse duration 148 fs, wavelength 775 nm) with Au films on silica substrates has been systemically studied. The single-pulse threshold can be obtained directly. For the multiple pulses the ablation threshold varies with the number of pulses applied to the surface due to the incubation effect. From the plot of accumulated laser fluence N × ?th(N) and the number of laser pulses N, incubation coefficient of Au film can be obtained (s = 0.765). As the pulse energy is increased, the single pulse ablation rate is increasing following two ablation logarithmic regimes, which can be explained by previous research. 相似文献
994.
采用空心毛细管束缚强飞秒激光脉冲在高压强气体中产生的成丝时,空心毛细管芯径对光谱展宽有着重要的影响. 研究了空心毛细管束缚成丝时,空心毛细管芯径对光谱展宽的影响. 结果表明,在低能量(0.4mJ)入射时,光谱展宽主要由成丝引起,而在高能量(1.3mJ)入射时,空心毛细管起到光波导效应参与了光谱展宽. 当能量介于二者之间时,采用芯径较小的空心毛细管,可以获得更好的光谱展宽效果.
关键词:
毛细管
成丝
束缚
光谱展宽 相似文献
995.
Adaptive synchronization between two different chaotic systems with unknown parameters 总被引:5,自引:0,他引:5
A unified mathematical expression describing a class of chaotic systems is presented, for which the problem of adaptive synchronization between two different chaotic systems with unknown parameters has been studied. Based on Lyapunov stability theory, an adaptive synchronization controller is designed and analytic expression of the controller and the adaptive laws of parameters are developed. The adaptive synchronizations between Lorenz and Chen systems, a modified Chua's circuit and Rössler systems are taken as two illustrative examples to show the effectiveness of the proposed method. 相似文献
996.
B. Chai S.-C. Zhang C.-R. Qiu H.-B. Zhang Y.-X. Lai Q. Xin 《International Journal of Infrared and Millimeter Waves》2007,28(6):423-432
A linear theory based on Maxwell-Vlasov equations and the Laplace transform is presented to describe the large-orbit coaxial-waveguide
cyclotron autoresonance maser (CARM) amplifier. A 35-GHz, TE5,1-mode large-orbit coaxial-waveguide CARM amplifier is specifically analyzed. Good agreement between the linear theory and
the nonlinear simulations is found in the exponentially growing region of the wave. Results show that the operating magnetic
field and the electron-beam energy and average radius substantially affect the power, and especially, a small beam current
may be unsuitable to a large-orbit CARM amplifier operation. 相似文献
997.
Photonic crystal fibers are a new class of single-material optical fibers with wavelength-scale air holes running down the
entire fiber length. Photonic crystal fibers were first developed in 1996 and have subsequently been the focus of increasing
scientific and technological interest in the field of fiber optics. The manufacturing, principles, basic properties, and some
applications of photonic crystal fibers are briefly described in this paper. A review of our recent work on the nonlinear
effects in photonic crystal fibers is presented, and special emphasis is placed on such effects as supercontinuum generation,
frequency conversion, and solitons observed when femtosecond light pulses propagate in these fibers. 相似文献
998.
Excited state absorption and stimulated emission of Nd3+ in crystals. Part 2: YVO4, GdVO4, and Sr5(PO4)3F 总被引:1,自引:0,他引:1
L. Fornasiero S. Kück T. Jensen G. Huber B.H.T. Chai 《Applied physics. B, Lasers and optics》1998,67(5):549-553
3+ ion in the crystals YVO4, GdVO4, and Sr5(PO4)3F. The measurements were performed in the spectral region of the main laser transitions 4F3/2→4I9/2, 4F3/2→4I11/2, and 4F3/2→4I13/2by a continuous wave pump and probe technique. The calibrated gain and ESA spectra are presented and possible implications
of ESA on the laser performance are estimated. It is shown that ESA can be a small loss factor to the laser emission near
1060 nm but does considerably diminish the effective emission cross sections near 1340 nm especially in Nd:YVO4 and Nd:GdVO4.
Received: 29 January 1998/Revised version: 8 May 1998 相似文献
999.
本文对新疆的十字花科9属9种杂草种子形状、大小、颜色及内部特征进行了描述,对种子外形、种皮进行电镜扫描,发现种皮微形态特征在种与种之间有明显的差异,并根据种皮微形态特征编制了分种检索表. 相似文献
1000.