准周期

摘要： 利用耗散结构理分析了蜡烛在有限开放区域内的准周期燃烧现象。通过建立一维对称模型和引入等效扩散系数简化了数学运算,得到浓度时变方程组。证明了模型定常解和对应稳定态的存在性,验证了火焰到边界的距离和对应的扩散约束影响蜡烛燃烧行为的结论。

摘要： 运用四阶Runge-Kutta求取了Lorenz系统的时间序列,采用小波分解与信息熵计算了时间序列的小波熵值,并用来测度系统准周期运动过程中的复杂度.计算结果表明,系统的三个运动复杂度分量均由许多大小不一、形状相似、山峰状的循环窗口组成,并且在不同的尺度上具有自相似特征,系统的小波熵序列也具有混沌性质,其运动具有准周期特性,进一步研究发现,在Lorenz系统运动的整个准周期过程中,运动复杂度的大小不同,复杂度大时,对应短准周期,复杂度小时对应于长准周期,系统的演变过程由各种不同的长准周期和短准周期交替组成.

摘要： 运用四阶Runge-Kutta求取了Lorenz系统的时间序列,采用小波分解与信息熵计算了时间序列的小波熵值,并用来测度系统准周期运动过程中的复杂度。计算结果表明,系统的三个运动复杂度分量均由许多大小不一、形状相似、山峰状的循环窗口组成,并且在不同的尺度上具有自相似特征,系统的小波熵序列也具有混沌性质,其运动具有准周期特性,进一步研究发现,在Lorenz系统运动的整个准周期过程中,运动复杂度的大小不同,复杂度大时,对应短准周期,复杂度小时对应于长准周期,系统的演变过程由各种不同的长准周期和短准周期交替组成。

摘要： 本文在循环频率域内分析心电信号的特性,解决了心电信号循环平稳度与其分段采集时长关系的问题.以德国PTB数据库采集的三导联心电信号为例,首先对原始心电数据进行预处理操作,随后利用二阶循环统计量,研究心电信号的循环平稳特性,并比较分析不同采集时长的心电信号的循环平稳特性,揭示了循环频率与多个时域周期一一对应的关系.本文仿真结果表明,心电信号的循环平稳特性并非时时刻刻都有所体现,只有在采集时间足够长的情况下,才会在循环频域内出现足够数量的循环频率点,即在时域内具有准周期性.

摘要： 利用1951-2016年河南省17个气象站及1870-1950年中国东、中部地区14个站点建站以来的逐月平均气温资料,采用多元线性回归法重建了1870-2016年河南省逐年平均气温序列,并分析了其变化特征.结果表明:(1)过去147a河南省气候经历了"冷-暖-冷-暖"的多年代波动.(2)1870年以来,河南省年均温最快30a和50a增暖速率发生于1900-1929年(0.046±0.018°C/a)和1883-1932年(0.031±0.008°C/a);最快30a和50a降温速率出现在1928-1957年(-0.043±0.024°C/a)和1923-1972年(-0.026±0.010°C/a).20世纪后期的变化速率均未超过以前水平.(3)1870-2016年河南省年平均气温的变化周期以2~4a和64a为主.前者变化可能受海气相互作用(如ENSO事件)及平流层准2a震荡(QBO)驱动,后者可能受太平洋年代际震荡(PDO)的影响.

摘要： 为揭示摆线钢球行星传动的非线性动力学行为,建立包括外部激励、啮合副啮合状态及啮合刚度等非线性因素的纯扭转强非线性耦合动力学模型.建立能够描述啮合副所处状态的预紧非线性函数,根据静力学分析获得啮合点静态变形量,建立非线性动力学微分方程组,利用数值分析方法获得系统随压缩量、阻尼系数变化的分叉图,并绘制不同参数下的相图和庞加莱图,研究不同参数对系统分叉特性的影响规律.结果表明:轴向压缩量对系统稳定性影响较大;轴向压缩量和旋转阻尼系数增加,高速运转的系统最终稳定于短周期运动,低速运转的系统最终稳定于准周期运动;阻尼较小时系统在低速状态下的稳定性较高,阻尼较大时系统在高速状态下的稳定性较高.%In order to reveal the nonlinear dynamic behavior of cycloid ball planetary transmission,a pure torsion strengthening nonlinear coupling dynamic model was established and external excitation and meshing pair meshing state and meshing stiffness of the nonlinear factors were included in the model.The nonlinear function of the preload was established to describe the state of the meshing pair.According to the static analysis,the static deformation of the meshing point was obtained,and then the nonlinear dynamic differential equations were achieved.,MATLAB was used to obtain the system with pressure shrinking,damping coefficient of variation of the bifurcation diagram and draw different parameters of phase diagram and Poincare map.The effects of different parameters on the bifurcation characteristics of the system were studied.The results show that the axial compression has a great influence on the stability of the system.Increase of axial compression and rotational damping coefficient,the system at high speed operation is stable in short period;the system at low speed operation is stable in the quasi periodic motion.The stability of the small damping system is higher in low speed state and the stability of the high damping system is high in the high speed state.

摘要： Based on the idea of multiple photonic bandgap (PBG) overlapping for a one-dimensional photonic crystal heterostructure, a novel hybrid quasiperiodic heterostructure is proposed to enlarge the omnidirectional photonic bandgap (OPBG). The heterostructure is formed by combining Fibonacci and Thue-Morse quasiperiodic structure. The results show that the OPBG of the heterostructure is enlarged obviously, which increases about three times compared with that of Fibonacci quasiperiodic structure, and twelve times compared with that of Thue-Morse quasiperiodic structure. The influences of structural parameters, such as period number and generation number, on PBGs of Fibonacci and Thue-Morse quasiperiodic structure are studied respectively. The results show that the parameters have little effects on PBG widths of the two quasiperiodic structures. The influences of the refractive indexes and thickness values of the high and low refractive index materials on OPBG of the heterostructure are also investigated. The results show that the OPBG of the heterostructure can be further broadened by increasing the refractive index ratios and thickness values of the high and low refractive index materials. The reason why the quasiperiodic structure can easily realize the multiple band gap overlapping is analyzed by comparing the bandgap properties of periodic structure. The number of PBGs of the quasiperiodic structure in the same wavelength range is more than that of the periodic structure. Moreover, with the increase of generation number of the quasiperiodic structure, due to the occurrence of PBG split, the number of PBGs increases obviously, and each PBG width is less than that of the periodic structure. Owing to this kind of PBG characteristic of the quasiperiodic structure, the heterostructure formed by cascading the two quasiperiodic structures is more prone to realizing the multiple PBG overlapping than other heterostructures, thus more easily achieving the expansion of OPBG. These results lay the design foundation for the compensation and broadening of the more complex bandgap structure.

摘要： Based on observed data, substitutive data, and scientific literature, this paper analyzes the main characteristics of precipitation variations over the last 60 years, 130 years, and 280 years and discusses the possible mechanism influencing precipitation variations on multi-decadal scales. Results showed the following: ( 1 ) The average annual precipitation anomaly percentage in the Haihe River Basin exhibited a decreasing trend during the period from 1956 to 2013, with a rate of decrease of 2.6% per 10 years, but the decreasing trend was weak during the period from 1880 to 2012. (2) During the period from 1736 to 2012, the average annual precipitation anomaly percentage in the Haihe River Basin did not show a significant long-term trend. A reduction in the trend of the average annual precipitation anomaly percentage in the Haihe River Basin appears to be a normal, but the fluctuation still existed on decadal and multi-decadal scales. (3) The period from the late 1940s to the early 1960s had the wettest climate conditions of the last 280 years. There have been several periods of persistent drought since the beginning of the 20th century, including the severe one, which has not been rare over the last 280 years, during the period from 1997 to 2003. The longest period of severe drought occurred from 1826 to 1843. (4) The average annual precipitation in the Haihe River Basin showed a characteristic of quasi-periodical fluctuation, and the relatively significant quasi-periods of fluctuation were 2 to 7 years, 11 years, 22 to 23 years, 33 years, and 63 to 65 years. (5) The reduction in the tendency of the precipitation in the Haihe River Basin after 1960s was a component of the natural low-frequency periodical fluctuation over 63 to 65 years in the regional climate. It is predicted that the annual precipitation in the Haihe River basin will increase over the next few decades, and it will probably reach its peak value during the period from 2035 to 2040.%根据器测资料、代用资料和文献资料,综合分析海河流域1956年以来、1880年以来和1736年以来降水量变化的主要特征,探讨影响降水多年代尺度变化的可能机制。结果表明：①海河流域平均年降水量距平百分率在1956-2013年表现出较明显下降趋势,每10 a下降速率为2.6%,但在1880-2012年期间下降趋势很弱；②1736-2012年,海河流域平均年降水量距平百分率未表现出任何长期趋势变化,1956年以来和1880年以来的趋势性减少现象也不再显得异常,但存在一系列年代到多年代尺度振动；③20世纪40年代后期到60年代早期是1736年以来最湿润阶段,但20世纪初以来几次持续性干旱,包括1997-2003年的严重干旱,在1736年以来历史上并非罕见,1826-1843年曾出现持续时间最长的严重干旱；④海河流域平均年降水量具有准周期性振动特点,较明显的准周期包括2~7 a、11 a、22~23 a、33 a和63~65 a；虞20世纪60年代后期以来海河流域降水的趋势性减少,是区域气候63~65 a自然低频周期性振动的组成部分,预计未来几十年整个流域降水量总体上将呈增多趋势,并可能在2035-2040年达到峰值区间。

摘要： We study the quantum pseudocritical points in the unbounded quasiperiodic transverse field Ising chain of finite-size systematically. Firstly, we study the derivatives of averaged magnetic moment and the averaged concurrence with transverse fields. Both of them show two visible peaks, with are nearly not raised when the length of chain is increased. Moreover, the places where the peaks occur in the transverse field are obviously different from that of the quantum phase transition point in the thermodynamic limit. These results are very different from those of the bounded quasiperiodic transverse field Ising chain and the disordered transverse field Ising chain. Then, we analyze the origin of the two visible peaks. For that we study the derivative of magnetic moment for each spin with transverse field. For all spins, the single magnetic moment only show one peak. However, the places where the peaks occur are not random. The peaks always occur in two regions. Thus, the derivatives of averaged magnetic moment reveal two peaks. Furthermore, we study the probability distribution of the pseudocritical points through finding out the peaks of the single magnetic moment in 1000 samples. The distribution is not Guassian. This result is obviously different from that of the disordered case. Besides, the pseudocritical points nearly do not occur at the quantum phase transition point. Finally, we analyze the origin of the pseudocritical points. For that we study the relationship between the spin places and the corresponding places of pseudocritical points. It is found that the pseudocritical points are caused by the two groups that exist in the nearest neighboring interactions of the unbounded quasiperiodic structure. When a spin is in one group, this group will decide the probable place of the pseudocritical point. Through this study, we find that although the quantum phase transition behaviors of the unbounded quasiperiodic transverse field Ising chain and the disordered transverse field Ising chain belong to the same universal class in the thermodynamic limit, the thermodynamic behaviors of the two Ising chains are very different as in finite sizes. The differences are caused by the special structure in the unbounded quasiperiodic system.

摘要： 本发明公开了一种准同步非周期扩频信号的快速捕获系统及方法，包括信号捕获功能模块、信号跟踪调节功能模块和预处理及下变频模块，所述预处理及下变频模块输入AD采样信号，输出数字基带信号，所述数字基带信号分别输入信号捕获功能模块和信号跟踪解调功能模块，所述信号捕获功能模块输出捕获结果到信号跟踪解调功能模块。本发明通过多个相关累加器对接收扩频信号进行捕获，充分利用了信号到达时刻先验信息，只有在信号到达时刻前才启动信号捕获流程。本发明通过例化多个相关累加器实现了一定时间范围内的并行捕获能力。

摘要： 本实用新型公开了一种中空式错位式周期分布准直器光纤滑环,本实用新型涉及光纤滑环技术领域，包括旋转构件、静止构件、扫描构件和信号传输系统，所述扫描构件包括扫描器，所述扫描器安装与旋转构件内；所述旋转构件包括旋转动态轴，所述旋转动态轴中部开设有第一贯穿孔；所述静止构件包括静态接收轴，所述静态接收轴的中部开设有与第一贯穿孔相互匹配的第二贯穿孔,所述旋转动态轴和静态接收轴之间同轴设置且通过轴承转动连接；所述信号传输系统包括光电转换组件和光信号旋转传递组件。本实用新型通过设置的旋转构件、静止构件、扫描构件和信号传输系统能够有效的解决工件位于轴心处信号传递的问题。

摘要： 本发明涉及一种具有多方向多波长准相位匹配倍频的二维准周期光子晶体，采用铁电晶体材料，其表面上转印成二维n重准周期图案，外加高压脉冲极化该晶体，晶体的超晶格格点被极化制成极化反转圆柱，超晶格形状为二维n重准晶排列；超晶格对应的倒格矢也是二维n重准晶形状；晶体的极化方向与二维准晶结构的中心轴平行。该光子晶体可以在不同的角度对多束不同波长的光波进行倍频；同时旋转一定的角度可得到相同的结果，降低了频率转换中转换效率对角度的敏感性；利用具有高重对称性的二维准晶结构可为实现准连续波长的倍频转换奠定一定的理论和实验基础。

摘要： 本发明涉及一种基于遗传算法优化的准周期超透镜。包括：基底和在基底上按黄金螺旋排序的纳米圆柱体，基于采用的介质材料，所述基底和纳米圆柱体通过基于等效介质理论进行初始结构参数的设计，并通过改进遗传算法进行结构参数的深度优化，提高整个超透镜的光学性能；其中对遗传算法的改进包括：改用三进制编码表达纳米圆柱直径的变化，以及采用分层迭代的方法来降低计算的样本空间。本发明是由纳米圆柱体按黄金螺旋排序组成的准周期超透镜，并引入遗传算法进行优化。该透镜集成度高，尺寸小，厚度薄，可以在微米量级，质量特别轻，因此特别适合设备系统小型化和快速定位与扫描。

摘要： 本发明涉及一种具有多方向多波长准相位匹配倍频的二维准周期光子晶体，采用铁电晶体材料，其表面上转印成二维n重准周期图案，外加高压脉冲极化该晶体，晶体的超晶格格点被极化制成极化反转圆柱，超晶格形状为二维n重准晶排列；超晶格对应的倒格矢也是二维n重准晶形状；晶体的极化方向与二维准晶结构的中心轴平行。该光子晶体可以在不同的角度对多束不同波长的光波进行倍频；同时旋转一定的角度可得到相同的结果，降低了频率转换中转换效率对角度的敏感性；利用具有高重对称性的二维准晶结构可为实现准连续波长的倍频转换奠定一定的理论和实验基础。

摘要： 本发明公开一种准周期大面积耐高温的红外热辐射器及其制备方法，该辐射器由多层膜结构组成，包括衬底、金属层、介质a、介质b，介质层厚度由遗传算法优化得出，每层厚度为100‑600nm，膜系的制备方法可以采用磁控溅射、离子束溅射、电子束蒸发、热蒸发、脉冲激光沉积、原子层沉积等其中的一种或者多种组合。这种红外辐射器具有高辐射率，峰值辐射率接近100％的优势，并且结构简单，易于大面积制备、波长可调控，可制备在柔性衬底上，能耐1000K高温等一系列优点，在红外光源、化学分子特征峰探测、红外成像、光电特征标识和新型红外光谱仪上有良好的应用前景。

摘要： 本申请涉及细胞排列技术领域，特别涉及一种基于声体波的实现细胞准周期图案排列的装置及方法。本申请提供的基于声体波的实现细胞准周期图案排列的方法包括以下步骤：将多个压电陶瓷片分别粘接在一多边形壳体的各个外壁上，得到声流控芯片；利用导线将各压电陶瓷片与信号发生器连接；将经离心后去除上清液的细胞加入到溶解成液态的水凝胶中，重新悬浮10～20次至混合均匀，得到细胞水凝胶溶液；将细胞水凝胶溶液滴加在多边形壳体围合成的容纳腔中，使细胞水凝胶溶液均匀铺展且无气泡，待液体稳定，启动信号发生器，向各压电陶瓷片施加信号，即实现细胞按照准周期图案排列。本申请提供的方法实现了微型化和集成化的细胞准周期结构图案化。

摘要： 本发明提供了一种可实现七种逻辑状态的六重准周期光子晶体全光逻辑门，包括若干介质柱，若干介质柱呈六重准周期型排列，形成若干同心圆环，从逻辑门的中心逆时针沿着0°、180°、240°和300°方向各删除一排介质柱构建出四条波导，其中两个波导作为输入端口，另外两个波导作为输出端口，输入端口的逻辑状态用BPSK技术控制；本发明在不改变光子晶体结构的情况下，通过改变两输入端口的初始相位，使不同相位的信号光在光子晶体内部发生干涉，从而可以产生七种不同的逻辑状态。

摘要： 本发明提供了一种基于Fabonacci准周期结构的非互易热辐射器，所述热辐射器包括由下到上依次设置的电介质衬底、金属反射镜和Fabonacci准周期磁光晶体结构层，所述Fabonacci准周期磁光晶体结构层包括设于金属反射镜上的电介质平板层和堆叠设于电介质平板层上的周期性堆叠层，所述周期性堆叠层包括磁光材料层和堆叠设于磁光材料层上的多层电介质平板层。本发明的基于Fabonacci准周期结构的非互易热辐射器，可以由镀膜工艺加工而成，取材方便，造价小，能大批量生产，具有重要的实用前景。

摘要： 本发明公开了一种基于双色准周期势场的高品质因子铌酸锂光子晶体微腔，涉及光信息处理技术领域。此双色准周期势场光子晶体微腔由多个A型微腔单元、多个B型微腔单元及两个线缺陷密铺而成，微腔单元由铌酸锂薄膜刻蚀圆台空气孔构成。微腔的品质因子主要由空气孔圆锥的侧面倾角，工作物质厚度，与光子晶体的晶格常数等参数决定。本发明提供的光子晶体微腔可在通讯波段工作；体积小、具有高的品质因子且设计简单，可应用于高次谐波产生、电光调制及光力振荡等过程。