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91.
提出把图象信息提取与光学内积关联技术结合起来识别图象的方法,并按照此原理,设计与组建了一个光电混合图象信息提取与关联识别系统。用0~9十个印刷体阿拉伯数字和八种中外飞机作为试验目标在系统上进行了识别实验。结果表明,印刷体数字和八种飞机的(可允许左右15°转动)识别率达100%,手写体数字的识别率也能达到70%左右。 相似文献
92.
熵在物理学中是一个十分重要的概念,但又是最为抽象的概念之一.本文从不同的角度出发给出熵的几种定义方法,并从多方面阐释熵的含义. 相似文献
93.
We demonstrate a diode-pumped passive Q-switched 946nm Nd: YAG laser with a diffusion-bonded composite laser rod and a co-doped Nd, Cr:YAG as saturable absorber. The average output power of 2.1 W is generated at an incident pump power of 14.3 W. The peak power of the Q-switched pulse is 643 W with 80kHz repetition rate and 40.8 ns pulse width. The slope efficiency and optical conversion efficiency are 17.6% and 14.7%, respectively. 相似文献
94.
Observation of stable bound soliton with dual-wavelength in a passively mode-locked Er-doped fiber laser 下载免费PDF全文
A phase-locked bound state soliton with dual-wavelength is observed experimentally in a passively mode-locked Erdoped fiber(EDF) laser with a fiber loop mirror(FLM). The pulse duration of the soliton is 15 ps and the peak-to-peak separation is 125 ps. The repetition rate of the pulse sequence is 3.47 MHz. The output power is 11.8 mW at the pump power of 128 mW, corresponding to the pulse energy of 1.52 nJ. The FLM with a polarization controller can produce a comb spectrum, which acts as a filter. By adjusting the polarization controller or varying the pump power, the central wavelength of the comb spectrum can be tuned. When it combines with the reflective spectrum of the fiber Bragg grating, the total spectrum of the cavity can be cleaved into two parts, then the bound state soliton with dual-wavelength at 1549.7 nm and 1550.4 nm is obtained. 相似文献
95.
Generation of 15 W femtosecond laser pulse from a Kerr-lens mode-locked Yb:YAG thin-disk oscillator 下载免费PDF全文
We demonstrated a robust power-scalable Kerr-lens mode-locked(KLM) operation based on a Yb:YAG thin-disk oscillator.15-W,272-fs pulses were realized at a repetition rate of 86.7 MHz with an additional Kerr medium and a 2.5 mm hard aperture in the cavity.247-fs pulses with an average power of 11 W could also be obtained by using a 2.4 mm hard aperture.Based on this shorter pulse,high efficient second-harmonic generation(SHG) was performed with a 1.7-mm-long Li B3O5(LBO) crystal.The SHG laser power was up to 5 W with the power fluctuation RMS of 1% measured over one hour. 相似文献
96.
Few-layer graphitic carbon nitride(g-C_3N_4) nanosheets were fabricated and utilized as a saturable absorber for mode-locking in an Er-doped fiber laser with net normal dispersion. The g-C_3N_4/polyvinyl alcohol(PVA) hybrid-film-based saturable absorber has a modulation depth of 4.01% and a saturation intensity of 7.5 MW/cm~2. By integrating g-C_3N_4-PVA mode-locker into the laser cavity, a mode-locked operation could be obtained. The achieved mode-locking pulse centered at 1530.3 nm has a pulse width of 530 ps. Its repetition rate is 40.8 MHz, and the corresponding signal-to-noise ratio is about 55 dB. 相似文献
97.
98.
Passively Mode-Locked Quasi-Three-Level Nd:LuVO4Laser with Semiconductor Saturable Absorber Mirror 下载免费PDF全文
We demonstrate a passively a Z-folded resonator. Using device, we achieve stable cw average output power under cw mode-locked Nd:LuVO4 laser operating on the quasi-three-level at 916nm with a semiconductor saturable absorber mirror (SESAM) as the passive mode-locking mode locking with 6.7ps pulse duration at repetition rate of 133 MHz and 88mW the pump power of 17.1 W. 相似文献
99.
100.
用修正的WCA状态方程和Ross变分微扰理论计算了液氩冲击压缩曲线,计算中体系分子间相互作用势选择EXP-6有效两体势模型,计算结果与Nellis等人的实验数据符合较好。 相似文献