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991.
An equivalent circuit model of millimeter wave second harmonic oscillator stabilized with a transmission cavity has been proposed
for constructing analytical formulations between performance parameters of the oscillator and parameters of the circuit. The
model consists of an equivalent circuit of fundamental wave and that of second harmonic wave. Each of the circuits comprises
circuit models of main cavity, transmission waveguide, and transmission cavity. Absorbing material placed between the transmission
waveguide and the transmission cavity can suppress additional resonances originated from transmission cavity. The behavior
of the second harmonic oscillator can be effectively described by the circuit model. Furthermore, based on this model, mechanical
tuning characteristics have been studied at first, and then analytical formulas for quality factor and efficiency depending
on circuit parameters have been derived. The circuit parameters can be conveniently extracted by electromagnetic field simulation.
Hence the formulas exhibit both compact form and enough accuracy. Thereafter, general rules of performance parameters varying
with circuit parameters have been deduced for the harmonic oscillators. Then some design considerations have been derived
according to the corresponding analysis. The equivalent circuit model is useful for designing and adjusting millimeter wave
second harmonic stabilizing oscillator with a transmission cavity. 相似文献
992.
Atsushi Kubo Tomoo Katsura Eiji Ito 《Journal of Physics and Chemistry of Solids》2008,69(9):2261-2264
By applying the numerical tensor analysis proposed by Yoneda and Kubo [Simultaneous determination of mean pressure and deviatoric stress based on numerical tensor analysis: a case study for polycrystalline X-ray diffraction of gold enclosed in a methanol-ethanol mixture. J. Phys.: Condens. Matter 18(2006)S979], we have determined deviatoric stress and mean pressure of polycrystalline MgO compressed in the Kawai-type apparatus. After the compression at room temperature, the mean pressure and the deviatoric stress in MgO were determined as 34.5 and 3.2 GPa, respectively. The mean pressure is significantly lower than the nominal pressure of 37.2 GPa determined by the conventional pressure determination method. By heating the sample to 1850 K with the constant press load, the deviatoric stress dramatically decreased to 0.1 GPa with a mean pressure of 34.2 GPa at room temperature after the heating. These results show both the importance of stress analysis to determine pressure more accurately and the effectiveness of annealing to reduce deviatoric stress in the sample. 相似文献
993.
The influence of single defects within a periodic structure on the nonlinear transmission of optical pulses through the structure is investigated numerically. A stack of alternating linear and cubically nonlinear layers of submicron thicknesses is considered. The simulations are based on a modified equation for the pulse envelope. Diffraction of the pulse has been taken into account, too. The results of simulations have been demonstrated as an essential influence of defects within the periodic structure on the nonlinear propagation of optical pulses, when the carrier frequency is chosen within the stop band of the structure with the defect. 相似文献
994.
Mechanisms of active control of sound transmission through a linked double-wall system into an acoustic cavity 总被引:2,自引:0,他引:2
The mechanism of active control on sound transmission through a mechanically linked double-wall structure into an acoustic cavity is investigated in this paper. Two control methods, i.e., structural control and acoustic control under two linkage cases (soft and hard) are investigated to analyze the effect of the links on the selection of control strategies and the corresponding control mechanisms. Simulations are performed to examine the dominant control mechanism (modal suppression or modal rearrangement) in different frequency ranges for each control case. The alteration in the structural-acoustic coupling is also analyzed so as to explain the mechanisms of sound attenuation. In addition, the dominance of the acoustic mode (0, 0, 0) in the energy transmission process as well as its use in designing a more effective sensor/actuator arrangement is discussed. 相似文献
995.
C. Orquiz-Muela J.A. Matutes-Aquino 《Journal of magnetism and magnetic materials》2008,320(14):e55-e57
Starting from arc-melted alloys, nanostructured Pr0.5Sm0.5Co5 powders were synthesized by mechanical milling and subsequent vacuum annealing during short times to develop an optimal microstructure with high hard magnetic properties. The best magnetic properties were obtained for the stoichiometric Pr0.5Sm0.5Co5 powders milled for 4 h and annealed at 800 °C for 1 min with a high coercitivity of 13.5 kOe, a high Mr/Mmax ratio of 0.72 and a maximum energy product of 11 MGOe. From X-ray diffraction and transmission electron microscopy, CaCu5-type phase and an average grain size of about 12 nm were determined in the annealed powders, and we calculated that 59% of the volume of the grains/crystallites are exchange-coupled. The observed magnetic hardening is associated to the high magnetic anisotropy field of the PrCo5 and SmCo5 phases and also to the microstructure developed by the processing used. 相似文献
996.
Fast sinter-crystallization of a glass from waste materials 总被引:1,自引:0,他引:1
E. Bernardo 《Journal of Non》2008,354(29):3486-3490
A glass belonging to the CaO-Al2O3-SiO2 system and corresponding to the melting of a mixture of industrial inorganic waste (feldspar mining residues, lime from fume abatement systems of the glass industry and recycled soda-lime glass) has been successfully transformed into dense and strong sintered glass-ceramics, even for very short holding times (30 min at 960 °C) and a very rapid heating, consisting of direct insertion of pressed fine glass powders in furnace (‘fast sinter-crystallization’). The addition of kaolin clay, conceived as binder for pressed glass powders, proved to positively influence the phase balance, the homogeneity and the degree of crystallization of fast sintered glass-ceramics, thus justifying the achievement of remarkable mechanical properties (bending strength exceeding 100 MPa, micro-hardness exceeding 7 GPa). 相似文献
997.
998.
制备了不同单体浓度的聚合物稳定铁电液晶器件,测试了震动实验和热稳定实验前后样品的排列织构、电光特性和对比度.用原子力显微镜研究了各样品的聚合物形貌,表明在器件内部形成了沿摩擦方向延伸的聚合物网络,并且随着单体含量的增加聚合物网络更加致密.由于聚合物网络体锚定的引入,使得铁电液晶分子在外力和温度场下的运动受到限制,聚合物体锚定的增强使聚合物稳定铁电液晶的稳定性也逐渐提高.实验结果表明,单体含量为4%时,聚合物稳定铁电液晶的抗震性和热稳定性良好,电光曲线为无阈值“V”字型,对比度达150∶1. 相似文献
999.
基于分步傅里叶法研究了艾里-高斯光束在三次聚焦和五次散焦竞争型非线性介质中交互作用的调控.结果表明:当入射角度为零时,同相位艾里-高斯光束相互吸引,五次散焦非线性强度较弱时,可形成周期逐渐缩短的呼吸孤子或强度不变的孤子.五次散焦非线性强度较强时,呼吸孤子的平均宽度变大甚至出现光束分叉现象,形成孤子对.反相位艾里-高斯光束相互排斥,排斥力随五次散焦非线性强度单调递增.当入射角度不为零时,通过控制光束入射角度的正负和初始间距.同相位和反相位艾里-高斯光束交互作用时可以同时表现出相互吸引和排斥的现象. 相似文献
1000.
Logic qubit plays an important role in current quantum communication. In this paper, we propose an efficient entanglement concentration protocol (ECP) for a new kind of logic Bell state, where the logic qubit is the concatenated Greenber–Horne–Zeilinger (C-GHZ) state. Our ECP relies on the nondemolition polarization parity check (PPC) gates constructed with cross-Kerr nonlinearity, and can distill one pair of maximally entangled logic Bell state from two same pairs of less-entangled logic Bell states. Benefit from the nondemolition PPC gates, the concentrated maximally entangled logic Bell state can be remained for further application. Moreover, our ECP can be repeated to further concentrate the less-entangled logic Bell state. By repeating the ECP, the total success probability can be effectively increased. Based on above features, this ECP may be useful in future long-distance quantum communication. 相似文献