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851.
In high power laser systems, the stability of the seed laser is vitally important. This paper presents the work on the design and manufacture of a highly stable LD pumped solid state seed laser which has the advantages of being all solid state, compact, easy to manufacture and low cost. The laser was composed of two parts. One was an LD pumped 0.5 mm thin Nd: YLF laser system in which the instability was around±6% (3σ). The other was a close-looped laser power control system using external cavity power feedback. Using an electro-optic modulator, a 1×2 optical fiber splitter and a signal processing circuit, we successfully realized the highly stable LD pumped Nd: YLF laser in which the instability of laser output power was lower than±0.2 %/hour (3σ). A digital PID (Proportion, Integration and Differentiation) control method was used with a control frequency of 40 kHz. The 3 mW of highly stable laser power through the optical fiber was obtained. 相似文献
852.
Frank Jochmann 《Journal of Differential Equations》2009,246(6):2151-513
This paper deals with a class of first-order systems with generally multivalued damping terms including Bean's model for superconductors with displacement current. The main goal is to prove the convergence of solutions to stationary states as t→∞. 相似文献
853.
854.
Four-wave mixing in semiconductor laser amplifiers enables various applications in photonic switching including wavelength conversion, space and time switching, optical phase conjugation, and demultiplexing. Switching times faster than 1 ps are possible. 相似文献
855.
K. L. Vodopyanov 《Optics Communications》1998,150(1-6):210-212
Infrared pulses, continuously tunable in the 8–13 μm range, and with up to 1 MW peak power, have been achieved using single-stage frequency conversion in a CdSe travelling-wave optical parametric generator, pumped by 100 ps pulses from an actively mode-locked, Q-switched and cavity dumped 2.8 μm Cr,Er:YSGG laser. The external quantum conversion efficiency reached 10%. 相似文献
856.
Zi -Cai Li 《Numerical Algorithms》1996,13(2):225-263
Let an image be distorted by a nonlinear transformationT, and then be restored back to its original by the inverse transformationT
–1. Such a cycle conversion,T
–1
T, of digital images can be facilitated by the combination (CSIM) given in [6] using the splitting-shooting method and the splitting-integrating method forT andT
–1 respectively. Since there is no need to solve nonlinear equations, CSIM has been widely applied to specific areas of image processing and pattern recognition, even those with complicated transformations, e.g., the harmonic transformation [12]; however, no strict error analysis has been provided so far. In this paper, a priori error estimates and convergence rates are derived for pixel greyness obtained from CSIM; also the analytical results are extended to the harmonic transformation. Numerical and graphical experiments are provided to support the theoretical analysis.Some preliminary results of this paper were presented at the 40th anniversary meeting of SIAM, Los Angeles, July 20–24, 1992. This work was supported in part by the Natural Sciences and Engineering Research Council of Canada, the Fonds pour la Formation de Chercheurs et l'Aide à la Recherche of Quebec by the Ministère de l'Enseignement Supérieur et de la Science (Action Structurante), and the Science Council of Republic of China under Grant No. NSC-85-2121-M-008. 相似文献
857.
Using the RHF/6-31G method calculations have been carried out on the isomeric chlorophosphoric heterocyclic molecules C6H4O2PCl2N=CClX3 and C6H4O2PCl=NCCl2CX3 (X = F and Cl) with full optimization of their geometries. Conclusions are drawn regarding the chlorotropic conversion of
these isomers which contain phosphorus with coordination numbers V and IV. The relative stabilization energies of the isomeric
compounds have been determined for variation of X.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 294–298, February, 2007. 相似文献
858.
大型抽样调查总是采用分层多阶段抽样.分层多阶段抽样若采用自加权的抽样设计,则总体总量的估计量形式简单,易于计算.本文提出了分层三阶段及以上抽样的自加权抽样设计方法. 相似文献
859.
讨论线性变换T的拟线性内逆与拟线性投影的关系.证得拟线性内逆M与T的零空间N(T)上的拟线性投影P及T的值域R(T)上的拟线性投影Q之间是1-1对应的,且满足P=I-MT,Q=TM. 相似文献
860.
Ichirou Yamaguchi Masayuki Yokota Takasi Ida Mizuki Sunaga Koichi Kobayashi 《Optical Review》2007,14(6):362-364
The state of drying paint is monitored from the dynamic behaviors of the speckle pattern arising from laser illumination of
the region inspected. Temporal variation of the peak height of the cross-correlation function between successive frames taken
with a fixed interval is plotted until the peak maintains a stationary maximum value. We used a speckle pattern in the diffraction
field for monitoring of a single region and that in the image field for simultaneous monitoring of various regions. Both the
normal and the phase-only algorithms were compared for cross-correlation computation. The former showed more distinct variation
of peak height. 相似文献