Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency domains.Three different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into account.Also,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss factor.Following the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COMSOL software.Subsequent parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse modes.The results show that considering the rubber viscoelasticity enhances the wave attenuation performance.Moreover,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal counterpart.The 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

THE 2-ERROR LINEAR COMPLEXITY OF 2~n-PERIODIC BINARY SEQUENCES WITH LINEAR COMPLEXITY 2~n-1

Linear complexity and k-error linear complexity of the stream cipher are two important standards to scale the randomicity of keystreams. For the 2n -periodicperiodic binary sequence with linear complexity 2n 1and k = 2,3,the number of sequences with given k-error linear complexity and the expected k-error linear complexity are provided. Moreover,the proportion of the sequences whose k-error linear complexity is bigger than the expected value is analyzed.

The k-Error Linear Complexity and the Linear Complexity for pq^n-Periodic Binary Sequences

The k-error linear complexity and the linear complexity of the keystream of a stream cipher are two important standards to scale the randomness of the key stream. For a pq^n-periodic binary sequences where p, q are two odd primes satisfying that 2 is a primitive root module p and q^2 and gcd（p-1, q-1） = 2, we analyze the relationship between the linear complexity and the minimum value k for which the k-error linear complexity is strictly less than the linear complexity.

ON A PROBLEM IN COMPLEX OSCILLATION THEORY OF PERIODIC HIGHER ORDER LINEAR DIFFERENTIAL EQUATIONS

In this article, the zeros of solutions of differential equation f^（k）（z）＋A（z）f（z） = 0, are studied, where k 2, A（z） = B（e^z）, B（ζ） = g1（1/ζ） ＋ g2（ζ）, g1 and g2 being entire functions with g2 transcendental and σ（g2） not equal to a positive integer or infinity. It is shown that any linearly independent solutions f1, f2, . . . , fk of Eq.（＊） satisfy λe（f1 . . . fk） ≥ σ（g2） under the condition that fj（z） and fj（z＋ 2πi） （j = 1, . . . , k） are linearly dependent.

Statistical Characteristics of the Complexity for Prime-Periodic Sequences

Using the fact that the factorization of x^N — 1 over GF(2) is especiallyexplicit, we completely establish the distributions and the expected values of the lineal complexityand the k-error linear complexity of the N-periodic sequences respectively,where N is an odd primeand 2 is a primitive root modulo N. The results show that there are a large percentage of sequenceswith both the linear complexity and the k-enor linear complexity not less than N, quite close totheir maximum possible values.

THE DISTRIBUTION FUNCTIONS FOR THE LINEAR COMPLEXITY OF PERIODIC SEQUENCES

Linear complexity is an important standard to scale the randomicity of stream ciphers. The distribution function of a sequence complexity measure gives the function expression for the number of sequences with a given complexity measure value. In this paper, we mainly determine the distribution function of sequences with period over using Discrete Fourier Transform (DFT), where and the characteristics of are odd primes, gcd and is a primitive root modulo The results presented can be used to study the randomness of periodic sequences and the analysis and design of stream cipher.

Fast algorithm for determining the minimal polynomial of up^n-periodic sequence

A fast algorithm for determining the minimal polynomial and linear complexity of a upn-periodic sequence over a finite field Fq is given.Let p,q,and u be distinct primes,q a primitive root modulo p2,m the smallest positive integer such that qm≡1 mod u,and gcd（m,p（p-1））=1.An algorithm is used to reduce a periodic upn sequence over Fq to several pn-periodic sequences over Fq（ζ）,where ζ is a u-th primitive root of unity,and an algorithm proposed by Xiao et al.is employed to obtain the minimal polynomial of each pn-periodic sequence.

Effect of incubation period on epidemic spreading in complex networks

We study the effect of incubation period on epidemic spreading in the Barabasi-Albert scale-free network and the Watts-Strogatz small world network by using a Suspectable-Incubated-Infected-Suspectable model. Our analytical investigations show that the epidemic threshold is independent of incubation period in both networks, which is verified by our large-scale simulation results. We also investigate the effect of incubation period on the epidemic dynamics in a supercritical regime. It is found that with the increase of incubation period Ω, a damped oscillation evolution of ρT （the ratio of persons in incubated state） appears and the time needed to reach a saturation value increases. Moreover, the steady value of ρT increases and approaches to an asymptotic constant with the value of Ω increasing. As a result, the infected ratio ρI decreases with the increase of Ω according to a power law.

Synthesis and Characterization of the Alkali Periodate Complexes of Rare Earths: M_2LnIO_6·xH_2O

The novel eomplexes of alkali and rare earth metal with periodate have been prepared for the first time. Chemical analysis indicates that the composition of the complexes is M_2LnIO_6·xH_2O(M=Li,Na,K;Ln=Pr, Tb),and all of the complexes have been characterized by UV-Visible,IR spectroscopic studies,susceptibility measurements and thermal analysis.

PERTURBATION RESULTS OF SECOND ORDER LINEAR DIFFERENTIAL EQUATIONS WITH PERIODIC COEFFICIENTS

Two perturbation results on the linear differential function f″ ＋ Π（z）A（z）f = 0 are obtained, where Π（z） and A（z） are periodic entire functions with period 2πi and σe（Π） 〈 σe（A）.

Periodate Oxidation of a Ternary Complex of Nitrilotriacetatochromium(III) Involving ß-Alanine as Co-Ligand

The kinetics of the periodate oxidation of chromium(III)-complex, [CrIII(NTA)(Ala)(H2O)]-(NTA = Nitrilotriacetate and Ala = ß-alanine) to Cr(VI) have been carried out for the temperature range 15°C - 35°C under pseudo-first order conditions, >>?[complex]. Reaction obeyed first order dependence with respect to and [Cr(III)], and the rate of reaction increases with increasing of pH for the range 3.40 - 4.45. Experimentally, the mechanism of this reaction is found to be consistent with the rate law in which the hydroxo species, [CrIII(NTA)(Ala)(OH)]2- is considerably much more reactive than their conjugate acid. ΔH* and ΔS* have been calculated. It is proposed that electron transfer occurs through an inner-sphere mechanism via coordination of to chromium(III).

Multipeaked Solitons in Parity-Time Complex Superlattice with Dual Periods

The existence and stability of multipeaked solitons are investigated in a parity-time symmetric superlattice with dual periods under both self-focusing and self-defocusing nonlinearity. For self-defocusing nonlinearity, dipole solitons with low power and all the odd-peak solitons can exist stably in the first gap, while dipole solitons with high power and even-peak （except two） solitons are unstable. For self-focusing nonlinearity, even-peak out-of-phase solitons can propagate stably in the infinite gap, while odd-peak in-phase solitons are unstable.

Ultrashort optical pulse shaper based on complex-modulated long-period-grating coupler

In this paper,we present a novel ultrashort pulse shaper based on complex-modulated long-period-grating coupler（CM-LPGC）.Temporal rectangular waveform with 2-ps full width at half maximum（FWHM） is obtained by transforming the input Gaussian pulse.Tolerances of the CM-LPGC-based shaper to various non-ideal excitation conditions and fabricating errors are investigated.Results confirm that CM-LPGC is stable and suitable for optical pulse shaping operation.

NUMERICAL ANALYSIS OF BIFURCATION BUCKLING FOR ROTATIONALLY PERIODIC STRUCTURES UNDER ROTATIONALLY PERIODIC LOADS

By considering the characteristics of deformation of rotationally periodic structures under rotationally periodic loads, the periodic structure is divided into some identical substructures in this study. The degrees-of-freedom (DOFs) of joint nodes between the neighboring substructures are classified as master and slave ones. The stress and strain conditions of the whole structure are obtained by solving the elastic static equations for only one substructure by introducing the displacement constraints between master and slave DOFs. The complex constraint method is used to get the bifurcation buckling load and mode for the whole rotationally periodic structure by solving the eigenvalue problem for only one substructure without introducing any additional approximation. The finite element (FE) formulation of shell element of relative degrees of freedom (SERDF) in the buckling analysis is derived. Different measures of tackling internal degrees of freedom for different kinds of buckling problems and different stages of numerical analysis are presented. Some numerical examples are given to illustrate the high efficiency and validity of this method.

高含水复杂断块油藏单层系边外注水开发模式

复杂断块油藏在开发后期面临综合含水率高、地层能量不足、剩余油分布复杂、井网适应性差等问题。以济阳坳陷沾化凹陷中部垦71断块油藏为例,基于水驱油藏的油包水和水包油2种油水分布状态,利用理论模型推导和数值模拟方法,开展了单层系边外注水开发模式研究。结果表明:从采液端和注水端的受力分析可获得单层系开发的合理注水量、合理采液量和合理注采井距,单层系开发的合理注水压差、合理注水量、合理采液量是影响其剩余油饱和度、含水饱和度的关键因素,对油层合理地层压力水平及剩余油二次富集起主要控制作用。通过加大注采井距至油水边界外围,以2.9倍含油条带宽度为合理注采井距的临界值,采用短注长静置的非对称周期注采方式,建立单层系边外注水开发模式,有利于保持单层系的压力系统稳定和提高剩余油波及率,从而提高原油采收率。矿场实践表明,采用单层系边外注水开发模式后,垦71断块油藏日产油量提高至254 t/d,含水率控制在93.7%,采收率提高至31.53%,采油速率提高4.9%,显示出良好的增产效果。单层系边外注水开发模式解决了高含水复杂断块油藏开发中的剩余油分布分散、水驱波及率低和井网适应性差等难题,可为复杂断块油藏开发提供指导和借鉴。

三维二十面体准晶弹性半平面周期接触问题研究

借助平面弹性复变方法,研究了周期刚性压头作用下三维二十面体准晶弹性半平面的周期有限摩擦和周期粘结接触问题.从应力、位移分量的复变函数形式表达式出发,利用半平面Hilbert核积分公式、Plemelj公式,得到两类周期接触问题的解答.针对周期有限摩擦接触问题,得到了三类周期刚性压头(直水平、直倾斜和圆形基底)作用在准晶体半平面上接触应力的封闭解.针对半平面周期粘结接触问题,求得接触边界上作用周期尖劈形位移时接触应力的显式解答.当不考虑相位子场的作用时,文中求得的理论结果可退化到正交各向异性材料平面弹性周期接触问题的对应结果.数值算例说明准晶弹性常数对接触应力分布规律及大小的影响.本文结论可为分析准晶材料压痕实验结果及准晶材料性能提供一定理论依据.

几类具有交织级联结构的伪随机序列的线性复杂度

为构造用于流密码的新的密钥流生成器,本文研究了结合交织和级联技术的伪随机序列的生成.通过计算多项式零点的个数,在特征为2的有限域上,获得了由Legendre序列和Hall序列构造的二元交织序列的线性复杂度.结果表明这些序列的线性复杂度大于其周期的一半,可抵抗Berlekamp-Massey(B-M)算法的攻击.

时变时滞奇异复杂动态网络的间歇控制与同步

利用周期性间歇控制策略研究了具有时变时滞的奇异复杂动态网络的指数同步问题.通过构建Lyapunov-Krasovskii泛函,推导出驱动系统和响应系统的指数同步判据;然后运用LMI工具箱求解线性矩阵不等式,得出了控制增益矩阵.最后,利用Runge-Kutta算法求解具有时变时滞微分代数方程,并通过数值仿真验证了结论的有效性.

铁-三联吡啶配合物活化高碘酸盐体系构建及其对染色废水的催化降解机制

为开发新型、高效的染色废水处理方法,通过铁-三联吡啶(Fe^(Ⅲ)(tpy)C_(l3))配合物活化高碘酸盐(PI)构建了Fe^(Ⅲ)(tpy)C_(l3)/PI催化氧化体系。在此基础上,采用酸性红1(AR1)作为染色废水模型污染物测试了该体系的催化降解性能,并通过捕获和探针实验研究了Fe^(Ⅲ)(tpy)C_(l3)配合物活化PI降解酸性红1的机制。结果表明:Fe^(Ⅲ)(tpy)C_(l3)配合物能够高效活化PI实现酸性红1的快速降解,15 min内对AR1的去除率高达98%;Fe^(Ⅲ)(tpy)C_(l3)/PI体系对酸性红1的降解符合伪一级动力学模型,同时酸性红1的降解速率常数随Fe^(Ⅲ)(tpy)C_(l3)配合物和PI浓度的增加而呈线性增加;在Fe^(Ⅲ)(tpy)C_(l3)/PI体系中包含超氧自由基、单线态氧以及高价铁,这些活性物质共同促进酸性红1的降解;该体系不仅对多种有机物的降解表现出普适性,同时催化降解过程不受溶液pH值以及常见无机盐离子的干扰。

DFA-ODENets:面向周期多阶段复杂系统的预测仿真框架

部分复杂系统受内外部因素影响在运行时会呈现出周期性的阶段变化,且在不同阶段具有完全不同的动态特性.因此在使用数据驱动方法解决此类系统的预测和仿真问题时,使用单一结构模型难以准确地学习系统在不同阶段的动态特性.本研究提出了基于确定性有限状态机-常微分方程网络的预测仿真框架(DFA-ODENets),以建模周期多阶段系统.该模型由多个ODENet组成,每个ODENet能够从不规则采样的序列数据中学习系统在各个阶段内的动态特性.同时模型集成了基于确定性有限状态自动机思想的阶段转换预测器以实现模型预测时在不同阶段之间自动转换.最后,将DFA-ODENet框架应用于某计算中心制冷系统的预测仿真场景中.模型能够在给定系统运行过程中的服务器负载和环境温度下模拟系统运行过程,并对系统的制冷功率、进气口温度等主要输出变量进行预测.其中,对于制冷系统能耗预测的平均相对误差在5%以内.同时,利用制冷系统仿真模型优化了系统停止制冷时的温度设定值,通过仿真实验表明该优化最高可以节省18%的制冷能耗.