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861.
Fu-Shun Lai Cheng Kuang Liu Jan-Ji Jou 《Photonics Technology Letters, IEEE》1999,11(5):545-547
The closed-form expressions of nonlinear Fourier transfer functions are presented for the analyzes of distortions and cross modulations in erbium-doped fiber amplifier (EDFA) systems. Based upon Volterra series and the time-dependent perturbation theory, the transfer functions are obtained after taking account of both the EDFA nonlinearity and chirping effect. Their applications to an AM-SCM and an eight-channel wavelength-division-multiplexed systems are demonstrated 相似文献
862.
Teh-Long Lai Yuan-Lung Lai Jen-Wei Yu Youn-Yuen Shu Chen-Bin Wang 《Materials Research Bulletin》2009,44(10):2040-2044
Coralloid nanostructured nickel hydroxide hydrate has been successfully synthesized by a simple microwave-assisted hydrothermal process using nickel sulfate hexahydrate as precursor and urea as hydrolysis-controlling agent. A pure coralloid nanostructured nickel oxide can be obtained from the nickel hydroxide hydrate after calcination at 400 °C. The thermal property, structure and morphology of samples were characterized by thermogravimetry (TG), temperature-programmed reduction (TPR), X-ray (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). 相似文献
863.
The coupled bridge foundation-superstructure finite-element code FLPIER was employed to predict the lateral response of the single piles and 3 × 3 to 7 × 3 pile groups founded in both loose and medium dense sands. The p-multiplier factors suggested by McVay et al. for laterally loaded pile groups with multiple pile rows were implemented for the predictions. The soil parameters were obtained through a back-analysis procedure based on single pile test results. The latter, as well as the numerical predictions of both the single and group tests, are presented. It was found that the numerical code FLPIER did an excellent job of predicting the response of both the single piles and the 3 × 3 to 7 × 3 pile groups. The latter involved the predictions of lateral load versus lateral deflection of the group, the shears and bending moments developed in the individual piles, and the distributions of the lateral loads in each pile row, which were all in good agreement with the measured results. 相似文献
864.
For mining extra-steep-thick coal seam, the sublevel top coal caving is a high efficient method in practical engineering.
However, major challenges associated with mining high-section top-coal-caving (HSTCC) are related to the resulting high ground
stresses. Inevitability, using the high-section sublevel top coal caving for extra-steep-thick coal seam, the large scale
of mined-out area appears. If the prefracture blasting and hydraulic fracture techniques are utilized, the top coal damage
and cracks will develop, and the mining complexity will increase, such as seam inclination, continuity, mechanical characteristics
of roof and susceptibility of top coal, etc. First, the field conditions of B1+2 seam were investigated at the +588 level of the Weihuliang Underground Mine of China. Subsequently, according to caving mechanism
of strata response obtained from several special models including physical simulation tests and numerical simulation models,
the prefracture process including blasting and injecting water were analyzed. Then, the prefracture blasting technique was
successfully applied to the caving of 52 m-sublevel seam. Finally, the effects were verified by advanced detecting instruments,
and the results show these methods and measurements are feasible and valid. 相似文献
865.
Kao H.L. Hung B.F. Chin A. Lai J.M. Lee C.F. McAlister S.P. Chi C.C. 《Microwave and Wireless Components Letters, IEEE》2005,15(11):757-759
A very low minimum noise figure (NF/sub min/) of 1.2 dB and a high associated gain of 12.8 dB at 10 GHz were measured for six-finger, 0.18-/spl mu/m radio frequency (RF) metal-oxide semiconductor field-effect transistors mounted on insulating plastic following substrate-thinning (/spl sim/30 /spl mu/m) and wafer transfer. Before this process, the devices had a slightly better RF performance of 1.1-dB NF/sub min/ and a 13.7-dB associated gain. The small RF performance degradation of the active transistors transferred to plastic shows the potential of integrating electronics onto plastic. 相似文献
866.
We study the bidirectional lightwave propagations in an erbium-doped fiber ring laser and an inverted-S fiber ring laser, and observe their optical bistability behaviors. We develop a model for the inverted-S fiber ring laser using nonlinear optical loop mirror and nonlinear amplifying loop mirror (NOLM-NALM) principle, which operates in the nonlinear region. Good agreements between the laser experimental performance and the developed model are achieved. The laser shows good switching and pulse compression capabilities. In addition, the laser model illustrates the route to chaotic operation via period doubling bifurcation, when the input power increases. We also obtain quasi-periodic operation when the laser is amplitude modulated experimentally. 相似文献
867.
Xiaoming Lai Torp H. Kristoffersen K. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1997,44(6):1332-1342
The conventional autocorrelation method (AM) to estimate the blood velocity for color flow imaging (CFI) is based on the phase estimation of the autocorrelation function. In this paper, a new extended autocorrelation method (EAM) that uses both phase and magnitude of the two dimensional (depth and temporal direction) autocorrelation function for estimating the blood velocity is presented. It is shown that the EAM has similar performance as the cross-correlation method (CCM). Both of them have smaller estimation variance than the AM and have the ability to estimate velocities beyond the Nyquist velocity, but the EAM is more computationally efficient than the CCM. A 2-D blood flow signal with rectilinear velocity including the transit time effect has also been simulated and the results are presented in this paper. For comparison, the EAM and the CCM have been applied to the simulated signals in which the flow velocities are up to four times the Nyquist velocity. The EAM has been further verified by experimental RF data from the subclavian artery 相似文献
868.
869.
京九铁路加筋土挡墙的离心模型试验验证了其总体设计方案的稳定性。对加施材料、墙体、面板等的模拟技术及其相似牢进行了探讨。同时,对NHRI—50gt离心机数据来集系统及测试技术进行了介绍。 相似文献
870.