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分层结构中兰姆波二次谐波发生的模式展开分析 总被引:1,自引:3,他引:1
采用二阶微扰近似和模式展开方法,对分层结构中兰姆波的二次谐波发生问题进行了深入研究,得到了二次谐波声场的一般表达式。兰姆波在分层结构中传播时,固体板材的体弹性非线性效应导致在各固体层的内部及表面出现二倍频的体驱动力及面驱动应力,其作用是在分层结构中激发出一系列二倍频兰姆波的简正模式,这些简正模式的叠加即构成分层结构中兰姆波的二次谐波声场。当构成二次谐波声场的某一二倍频兰姆波简正模式的相速度等于基频兰姆波的相速度时,该二倍频兰姆波简正模式分量表现出随传播距离积累增长的性质。本文还就铝板-环氧粘接层-铝板结构中兰姆波的二次谐波声场进行了数值分析,结果显示,软粘接层性质对二次谐波声场的影响很大。 相似文献
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The metastable phase of well-faceted, hexagonal, prism-like molybdenum oxide hydrate (MoO3·0.55H2O) was successfully synthesized by evaporating molybdic acid solution prepared through cation membrane electrolysis of Na2MoO4·2H2O aqueous solution. The obtained crystals were characterized by X-ray diffraction (XRD), thermogravimetric (TG), scanning electronic microscopy (SEM) and photoluminescence (PL) spectrophotometry. The as-prepared MoO3·0.55H2O rods were of 2–4 μm in width and 5–12 μm in length. The MoO3·0.55H2O microrods displayed photoluminescence properties at room temperature and were transformed into stable orthorhombic α-MoO3 after air annealing at 380 °C. Moreover, the influence of temperature factor on the phase transformation process, morphology and photoluminescence properties of MoO3·0.55H2O was investigated in detail. 相似文献
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Fengfeng Chi Yanguang Qin Shaoshuai Zhou Xiantao Wei Yonghu Chen Changkui Duan Min Yin 《Current Applied Physics》2017,17(1):24-30
In order to clarify the site occupancy of rare-earth ions in rare-earth doped perovskite materials, the un-doped pure CaTiO3 and Eu3+-doped CaTiO3 samples with a series of Ca/Ti ratio were synthesized via high-temperature solid-state reaction method. X-ray diffraction (XRD) powder patterns confirm that the crystal structure keeps invariant at various Ca/Ti ratios. Measurement results of unit-cell parameters and X-ray photoelectron spectroscopy (XPS) indicate that Eu3+ ions enter into the Ca2+ site. The high-resolution photoluminescence spectra of Eu3+ ions at 20 K in all samples did not witness a significant change under the excitation at different wavelength, implying that Eu3+ ions occupy only one type of site. Considering the small spectral splitting range of 5D0 → 7F2 transition and the large intensity ratio of 5D0 → 7F2/5D0 → 7F1, it can be concluded that Eu3+ occupies Ca2+ site with larger coordinate numbers rather than Ti4+ site. 相似文献
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LIU Ge LU YuanRong YIN XueJun ZHANG XiaoHu DU Heng JIANG PeiYong LI ZhongShan LI XiaoNi HE Yuan WANG Zhi GAO ShuLi YANG YaQing ZHU Kun YAN XueQing CHEN JiaEr YUAN YouJin XIA JiaWen ZHAO HongWei 《中国科学:物理学 力学 天文学(英文版)》2014,57(7):1311-1317
The 53.667 MHz continuous-wave heavy ion RFQ has been designed and manufactured for the SSC-LINAC project.This four-rod RFQ accelerates ions with maximum mass to charge ratio of 7 from 3.728 keV/u to 143 keV/u.Measurements have been carried out to check the RF performance of the cavity and the quality of the electric field.The S11 of the power coupler is adjusted to better than-44 dB,and the Q0 of the cavity is 6440.The quality of the electric field is evaluated by the perturbation method.The measurement procedure and data analysis will be discussed in detail.The error due to gravity of the perturbation bead has been corrected by averaging the fields in different quadrants.As a result,the unflatness of the electric field is±2.5%,and the dipole field component distributes from 0%to 20%in different longitudinal positions,which indicates the asymmetry of the quadrupole field.The unflatness of the quadrupole field distribution represents a good agreement with the simulation results.High power RF test and beam commissioning of the RFQ are on schedule in early 2014. 相似文献
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ZaiHong Yang YanLin Ye ZhiHuan Li JianLin Lou FuRong Xu JunCheng Pei ZhengYang Tian KuoAng Li YeLei Sun Jie Chen Jing Li Wei Jiang Biao Yang SiDong Chen Qiang Liu HongLiang Zang Jun Feng ZheWei Yin 《中国科学:物理学 力学 天文学(英文版)》2014,57(9):1613-1617
From an inelastic excitation and breakup experiment with a 12Be beam at 29 MeV/u, a large 4He+8He cluster decay width of 1.1(2) MeV is determined for a state at an excitation energy of 10.3 MeV and with a spin parity of 0+. By using the R-matrix analysis, a cluster spectroscopic factor of 0.53(10) is extracted from the cluster partial width, providing a strong support for the clustering structure in 12Be. A specially designed zero-degree telescope played an essential role in the present experiment and has been demonstrated to be a promising tool in future studies of the molecular-like resonances near the cluster separation threshold. 相似文献
100.
We demonstrate the continuous wave p-polarized single longitudinal mode (SLM) operation of an Er:YAG laser at 1617.6nm pumped by a diode-laser with three inserted Fabry-Perot (FP) etalons at room temperature. The Brewster angle inserted FP is applied to obtain the p-polarized laser. For free running, the maximum output power is 570 m W with a pump power of 12.5 W. An incident pump power of 12.5 W is used to generate the maximum p-polarized single longitudinal mode output power of 78.5 m W, corresponding to a slope efficiency of 1.6% and an optical-to-optical efficiency of 0.61%. The beam quality M2 is measured to be 1.15 at the highest SLM output power. This stable polarized SLM oscillation is encouraging due to its application for an injection-locked system used as a master laser. 相似文献