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361.
362.
A series of fully three-dimensional(3 D) numerical simulations of flow past a free-to-oscillate curved flexible riser in shear flow were conducted at Reynolds number of 185–1015. The numerical results obtained by the two-way fluid–structure interaction(FSI) simulations are in good agreement with the experimental results reported in the earlier study. It is further found that the frequency transition is out of phase not only in the inline(IL) and crossflow(CF) directions but also along the span direction. The mode competition leads to the non-zero nodes of the rootmean-square(RMS) amplitude and the relatively chaotic trajectories. The fluid–structure interaction is to some extent reflected by the transverse velocity of the ambient fluid, which reaches the maximum value when the riser reaches the equilibrium position. Moreover, the local maximum transverse velocities occur at the peak CF amplitudes, and the values are relatively large when the vibration is in the resonance regions. The 3 D vortex columns are shed nearly parallel to the axis of the curved flexible riser. As the local Reynolds number increases from 0 at the bottom of the riser to the maximum value at the top, the wake undergoes a transition from a two-dimensional structure to a 3 D one. More irregular small-scale vortices appeared at the wake region of the riser, undergoing large amplitude responses. 相似文献
363.
New multi-color BV RcIcphotometric observations are presented for the W UMa type eclipsing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124(±0.011). We collected all available times of light minima spanning 119 yr,including CCD data to construct the O-C curve, and performed detailed O-C analysis. The O-C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic variation exist. The period is decreasing at a rate of P =-1.04(±0.18) × 10~(-10) d cycle~(-1) and, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P_3= 82.7(±3.6) yr and an amplitude of A = 0.028(±0.002) d may be explained by magnetic activity of one or both components or the light travel time effect caused by a distant third companion with M_3(i′= 90?) = 0.511 M_⊙. 相似文献
364.
Humans and livestock have always dwelling together, especially in rural areas. Based on a multi-method approach of ethnographic fieldwork, grounded theory and one-way multivariate analysis of variance, this paper explores human and livestock dwelling. The findings show that human and livestock dwelling form a special type of human dwelling place, with forms defined as co-, mix- and dis-dwelling. Then, from co-, mix- to dis-dwelling constructed a story line to the evolution of human and livestock dwelling forms, which further explains the entire dwelling situation of humans and livestock, including the dimensions of human dweller, livestock dweller, the rural environment and special events. Among co-, mix- and dis-dwelling significant differences existed between human and livestock individuals, the nature of rural environment, vernacularity and rural tourism development. Between co- and dis-dwelling, significant differences existed in seventeen aspects; between mix- and dis-dwelling, significant differences existed in eleven aspects; meanwhile, no significant differences existed between co- and mix-dwelling. Accordingly, this suggested that human and livestock dwelling forms can be divided into mix- and dis-dwelling. This study on humans and livestock dwelling relationship offer a new perspective on rural and animal geography. This paper is an exploratory foray into rural dwelling geography as part of the Anthrozoology study and broadens the scope of extant scholarship on human dwelling morphology, as well as analyses the spatial relationships between human and livestock dwelling. 相似文献
365.
深弹发射装置安装在甲板部位,使用环境恶劣,过去均采用传统的试验方法进行环境适应性考核。最近几年,随着三维设计的广泛应用,仿真技术也开始发挥作用,以发射装置接线箱的冲击响应为例,介绍仿真技术在发射装置环境适应性分析中的应用。通过案例分析可知,仿真分析对于发现机械结构设计中的薄弱环节还是非常有效的,它突破了环境试验受限于试验样机和特定环境条件的限制,可以在较短的时间内得到仿真结果,对装备模型进行及时修正。 相似文献
366.
利用扫描近场光学显微镜观测并分析了两种表面等离子体激元纳米结构对表面等离子体激元(SPP)的激发和聚焦现象. 用线偏振光照射有半个周期相位差的环状沟槽结构与有半个周期位相差的环状狭缝结构,得到了单点的SPP聚焦. 有限时域差分法的模拟结果验证了实验中观测的现象. 这两种相位错位的表面等离子体激元纳米结构,突破了由于干涉导致的线偏振光不能得到单个聚焦点的限制. 与采用径向偏振光激发而得到单个聚焦点的方法相比,线偏振光不需要聚焦,也不需要将光束中心对准纳米结构的几何中心即可得到单点聚焦. 相似文献
367.
This paper studies the average fidelity of teleportation and thermal entanglement for a two-qubit Heisenberg XYZ chain in the presence of both an inhomogeneous magnetic field and a Dzyaloshinski--Moriya interaction. It shows that for a fixed Dz, the increase of bz will broaden the critical temperature at the cost of decreasing the thermal entanglement. And it can modulate the inhomogeneous magnetic field and the Dzyaloshinski--Moriya interaction for the average fidelity of teleportation to be optimal. 相似文献
368.
As the feature size of the CMOS integrated circuit continues to shrink, the more and more serious scattering effect has a serious impact on interconnection performance, such as delay and bandwidth. Based on the impact of the scattering effect on latency and bandwidth, this paper first presents the quality-factor model which optimises latency and bandwidth effectively with the consideration of the scattering effect. Then we obtain the analytical model of line width and spacing with application of curve-fitting method. The proposed model has been verified and compared based on the nano-scale CMOS technology. This optimisation model algorithm is simple and can be applied to the interconnection system optimal design of nano-scale integrated circuits. 相似文献
369.
动态外部性视角的企业再地方化效应及地区影响 ——以皖江产业承接示范区为例 总被引:3,自引:2,他引:1
基于动态外部性视角,提出再地方化效应的测度及对地区转型发展的作用机理,以皖江产业承接示范区为研究对象,从MAR外部性、Jacobs外部性和Porter外部性3方面分析企业再地方化效应的时空演化特征,运用双向固定效应模型验证其对皖江示范区转型发展的影响。研究表明:① 时间演化特征与各城市的产业承接政策和转入的产业类型不同有关;② 空间上MAR外部性呈现出“总体均衡-向西增强-向南增强”的演化特征,Jacobs外部性由西南向东北逐渐增强,Porter外部性整体呈增强态势;③ MAR外部性对区域经济绩效和创新水平的效应均表现为“倒U”型;Jacobs外部性能够显著促进地区经济发展,但对区域创新的效应为“U”型;Porter外部性能够推动地区经济发展,但不利于区域创新。 相似文献
370.
基于2000~2015年中国省(市、区)土地行政复议案件数量、案由与复议结果等数据,定量探究中国土地行政复议案件的分布特征、格局演变与宏观驱动机制。研究表明:中国年度土地行政复议案件数量整体呈连续增加态势,行政相对人复议成功率先下降后上升。土地行政复议案件的空间分布与中国宏观人口-经济格局基本匹配,整体具有东南多西北少的分异特征,以中部主要省份为核心,经历了先向东部沿海、后向西北与西南地区蔓延的演进过程。中国土地行政复议案件的时空格局演变由经济发展水平、城市化水平、产业结构升级、城市建成区面积、土地财政收入状况、土地市场化水平、区位条件等因素共同驱动。 相似文献