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51.
预应力索网天线结构优化设计 总被引:1,自引:0,他引:1
索网预拉力设计是索网天线结构设计的一个重要内容.针对三向网格旋转抛物面索网天线结构,首先在不计桁架结构受力变形的条件下,从索网节点的力平衡方程出发,以索网结构的结构特征为依据,以网面索段最大拉力比最小为设计目标,给出了索网结构预拉力优化设计的有效方法;其次,考虑到在索网结构的拉力作用下,桁架结构的微小变形将导致网面索段的拉力均匀性变差,通过调节索网挂接节点的位置,对桁架结构的受力变形进行了有效补偿,改进了预应力索网天线结构的整体设计方案.算例分析结果表明,天线结构网面索段的实际设计最大拉力比为1.30,验证了方法的正确性及有效性. 相似文献
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We study the exponential sums involving l:burmr coeffcients ot Maass forms and exponential functions of the form e(anZ), where 0 ≠ α∈R and 0 〈 β 〈 1. An asymptotic formula is proved for the nonlinear exponential sum ∑x〈n≤2x λg(n)e(αnβ), when β = 1/2 and |α| is close to 2√ q C Z+, where Ag(n) is the normalized n-th Fourier coefficient of a Maass cusp form for SL2 (Z). The similar natures of the divisor function 7(n) and the representation function r(n) in the circle problem in nonlinear exponential sums of the above type are also studied. 相似文献
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Guowei Lu Yuwei Wang R. Yuanying Chou Hongming Shen Yingbo He Yuqing Cheng Qihuang Gong 《Laser \u0026amp; Photonics Reviews》2015,9(5):530-537
Directional side scattering of light by individual gold nanoparticles (AuNPs) trimers assembled by the atomic force microscope (AFM) nanomanipulation method is investigated in experiment and theory. The AFM nanomanipulation approach brings an active way to construct ultracompact and effective optical nanoantennas. Different configurations of the trimers are constructed in situ via AFM nanomanipulation. Unidirectional side scattering of light by a single trimer is demonstrated with a broad response bandwidth over 400 nm and directivity up to ∼7.8 dB in experiments. The near‐field plasmon coupling of the AuNPs is simulated with the 3D finite‐difference time‐domain method and the far‐field radiation patterns are calculated by employing near‐field‐to‐far‐field transformation methods. The calculated results are in agreement with the experiments qualitatively. The physical origin is revealed intuitively by employing a simple phenomenological “two‐dipole” model. The unidirectional light scattering is due to the interference between multiple plasmonic resonance modes of the trimers. The study contributes to the understanding of the optical response of complex nanostructures and optimizing nanoantenna performances for practical applications, e.g. increasing the detection efficiency of surface‐enhanced spectroscopy.
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用微波辐射法合成了(Ce0.67Tb0.33)MgAl11O19(PG)和BaMgAl10O17(PB)两种荧光体,经X射线粉末衍射分析,其d值和I/I0值与JCPDF3673和26163基本一致。计算得到PG的晶胞参数a=05582nm,c=21884nm;P-B的晶胞参数α=05616nm,c=22614nm。测定了两种荧光体的激发光谱和发射光谱。P-G的色坐标x=0316,y=0565;P-B的色坐标x=0156,y=0106。与市售同类荧光粉相比,P-G的相对发光强度为88%,P-B的相对发光强度为80%。 相似文献
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In this investigation new superporous hydrogels composites based on aqueous Carbopol® solution (SPHCcs) were prepared. SEM images indicated that the inner surface of SPHCcs contained a lot of pores connected each other and the outer surface of them was non-porous. The swelling ratio decreased with increasing the content of aqueous Carbopol® solution, and the final swelling ratio was similar to that of the SPH although the initial swelling ratio was lower. The density measurement revealed that the porosity increased when aqueous Carbopol® solution was incorporated. It was observed from in vitro bioadhesive force study that SPHCcs adhered to the intestinal mucosal more quickly and exhibited higher mucoadhesion as compared with SPH. It is evident that the hydrogels synthesized in this study could be a potential candidate for transmucosal drug delivery system. 相似文献