一维非线性链自由能的计算

研究了一维非线性链孤立子的统计性质．引进平移模作为完备基，把系统作为无相互作用的孤立子（反孤立于）一声子组成的“理想气体”，采用巨正则系综计算了低温条件下系统的自由能密度．

基于非线性磁链动态模型的无速度传感器矢量控制系统

在实际工况下,异步电机参数变动会导致基于转子磁场定向的矢量控制系统定向出现偏差。针对此问题提出了一种非线性磁链动态模型的数学模型。该模型在高速运行时采用电压模型进行磁链估计,低速时采用电流模型补偿,在不同范围内各自的比例不同。结合异步电机数学模型,推导了闭环观测器的非线性磁链动态模型,在对其做近似线性化处理后建立了在不同速度范围内的切换机制,利用稳定性理论分析了误差相关因素,并对电机参数进行敏感性分析和补偿。仿真和实验结果验证了理论分析的正确性。

一维非线性双原子链晶格振动的色散关系

在小振动情况下 ,讨论非简谐项对一维双原子链晶格振动色散关系的影响 ;对于三次方在位非线性力的作用 ,得到一维双原子非线性链晶格振动的色散关系 ,分析了光频支和声频支色散关系在非线性作用下的变化 ;色散关系的频隙在非线性力的作用下发生变化 ,且频隙的位置将降低 (非线性系数为正 )或升高 (非线性系数为负 ) .

测度链上的非线性微分方程的正解

应用锥理论和不动点指数方法，在与相应的线性算子第一特征值有关的条件下，获得了测度链上的非线性微分方程Lx（t）=-[τ（t）x^△（t）]^△=f（t，z（σ（t）））的正解的存在性．

应用微分方程解非线性尺寸链

平面尺寸链中,封闭环尺寸可以为非线性函数。对于非线性尺寸链,既有长度尺寸变量,又有角度尺寸变量,不能运用简单的代数和求解。为了简化问题,往往忽略角度误差的影响,把角度视为常量,简化为线性尺寸链求解。事实上,角度误差对封闭环尺寸的影响是不应忽视的。应用全微分概念,不忽略角度误差的影响,解非线性尺寸链,概念清晰,计算精确。

非线性平面尺寸链中封闭环求解方法探讨

本文在合理假设的基础上运用近似计算，利用极大极小法原理和概率与数理统计理论推导出非线性平面尺寸链中求得封闭环的基础表达式，并通过应用实例说明求得方法及表达式的有效性和适应性。

非线性弹簧链在自洽场理论中的应用

传统的高斯链自洽场理论不适用于聚合物链高度强伸展的体系。为了弥补这一缺陷,发展了一种基于聚合物珠链模型的自洽场理论方法,其中聚合物链上的珠子通过非线性Warner弹簧势(Warner spring potential)连接。通过赝谱方法求解自洽场方程,并将该方法应用于两嵌段共聚物的微相行为研究,验证了方法的有效性。研究中,构建了层状结构周期与Flory-Huggins参数、非键势作用范围及聚合度的标度关系,发现所得的标度关系与强分离理论预测的结果吻合。此外,研究了极限键长对微相行为的影响,研究表明通过改变极限键长可以将自由结合链模型和高斯链模型关联起来。该方法可应用于传统高斯链自洽场理论不适合的体系,如低盐浓度下的强聚电解质体系等。

基于非线性正交磁链观测器的交流电动机直接转矩控制

高性能直接转矩控制系统的关键之一是磁链的准确观测,结合一种适合交流电动机直接转矩控制的非线性正交反馈补偿定子磁链观测器,该观测器从确保磁链和反电势正交的角度出发,保证了电机在宽运行范围定子磁链观测的准确性,仿真和实验表明,该观测器能在宽速度范围内精确地估算电机定子磁链,实现感应电机直接转矩控制系统的高性能控制。

基于迁移学习的快速多边响应法

针对基于多边响应的快速时域仿真计算中,需要通过瞬态仿真得到所有边沿响应的时间花费问题,提出了基于迁移学习的多响应预测方法。首先,根据非线性链路的响应特点,将拖尾响应划为线性区和非线性区分别处理,以减少所需测量的响应长度;其次,以“0电平”响应作为源域数据构建预训练模型网络;然后,利用预训练模型的网络参数训练其他三种响应的迁移学习模型;最后,将所有非线性区响应绘制在一个单位间隔内,并将线性区的积累电压扩充至眼图轮廓。实验结果表明,该方法能以更少的响应数据,更全面且准确预测其余响应,从而提高快速多边响应法的计算速率。

关于φ~4-链的一种新的变分近似及量子统计修正

该文给出一种新的变分形式计算配分函数，与通常的方法不同，我们导出自由能的下界。应用这一方法，我们讨论了φ４－链经典配分函数的计算。

永磁同步电机直接转矩控制的磁链观测研究

对永磁同步电机直接转矩控制中磁链观测这一关键技术进行了研究,设计了一种新型磁链观测器——非线性正交反馈补偿磁链观测器,分析了其在永磁同步电机直接转矩控制中的优势,建立了基于Simulink(Matlab)软件的永磁同步电机直接转矩控制仿真模型,对所提出的磁链观测方案进行了仿真分析,仿真结果验证了该方案的可行性。

阻尼作用下一维非线性单原子链中的孤子

利用多重尺度法 ,研究了弱阻尼作用下一维非线性单原子链中的波动行为 ,发现在O(ε)级阻尼作用下其格波幅度减小 ,群速变慢 .在晶格动力学中导出了参数耗散型非线性Schr dinger方程 ,对方程进行解析求解 .结果表明 :在O(ε)级阻尼作用下一维非线性单原子链中的格孤波为传播的包络孤子 ;在O(ε2 )级阻尼作用下 ,格孤波为钟状或扭结的孤子 .

两约束路由问题的近似解法

首先回顾了一些重要的QoS路由算法,然后对关于两约束路由问题(BCP,bi-constraintpath problem)的线性搜索算法进行了数学分析,确定了搜索因子的范围和最佳搜索因子的值。基于以上分析,我们给出了BCP和单约束最短路径问题(RSP,restricted shortest path problem)的近似算法,并对算法性能进行了分析;最后,本文研究了采用非线性链路代价函数求解BCP。测试结果表明本文提出的算法是求解BCP和RSP的有效算法。

“瞬间结构”与斯托克豪森的《瞬间》

瞬间结构是20世纪下半叶音乐中出现的一种重要结构概念,由斯托克豪森首次提出并广泛运用于他及后人的音乐创作中。文章从术语概念、历史形成、形态特征、技术细节等方面梳理了瞬间结构的有关情况,具体分析了斯托克豪森的同名大型管弦乐作品《瞬间》的结构程序,归纳出3种核心结构素材:K-素材、M-素材与D-素材,与4种主要结构组织手段:树形结构、移动设计、插入程序与非线性链接,并指出瞬间结构与物理时间相对性的内在联系。

Nonlinear Coupled Analysis of a Single Point Mooring System

Coupled effects on a single point mooring(SPM) system subjected to the combined action of wind,waves and current are studied in this paper. Due to the complicatedness of the sea state and the huge size of the vessel,physical experimental study is both time consuming and uneconomical,whereas the numerical study is cost-effective and DNV software provides powerful SESAM software in solving the issues. This paper focuses on the modeling process of the SPM system,catenary equilibrium calculation,static analysis of the vessel in three different scenarios,and dynamic response simulation of the SPM system under environmental excitations. The three scenarios in study are as follows:the SPM is under the combined function of(a) wind,waves and current,(b) wind and waves,(c) current and waves. They are so set that one can compare the contributions of different types of loads in both static and dynamic studies. Numerical study shows that wind and current are the two major factors contributing to the mooring line tension,and surge and sway are the two dominant motions of the moored vessel subjected to environmental excitations.

Nonlinear Analysis of Flexible and Steel Catenary Risers with Internal Flow and Seabed Interaction Effects

Flexible risers and steel catenary risers often provide unique riser solutions for today’s deepwater field development. Accurate analysis of these slender structures, in which there are high-speed HP/HT internal flows, is critical to ensure personnel and asset safety. In this study, a special global coordinate-based FEM rod model was adopted to identify and quantify the effects of internal flow and hydrostatic pressure on both flexible and deepwater steel catenary risers, with emphasis on the latter. By incorporating internal flow induced forces into the model, it was found that the internal flow contributes a new term to the effective tension expression. For flexible risers in shallow water, internal flow and hydrostatic pressure made virtually no change to effective tension by merely altering the riser wall tension. In deep water the internal pressure wielded a dominant role in governing the riser effective tension and furthering the static configuration, while the effect of inflow velocity was negligible. With respect to the riser seabed interaction, both the seabed support and friction effect were considered, with the former modeled by a nonlinear quadratic spring, allowing for a consistent derivation of the tangent stiffness matrix. The presented application examples show that the nonlinear quadratic spring is, when using the catenary solution as an initial static profile, an efficient way to model the quasi-Winkler-type elastic seabed foundation in this finite element scheme.

Distribution of Vibrational Energy Levels of Protein Molecular Chains

The distributions of the quantum vibrational energy levels of the protein molecular chain are found by the discretely nonlinear Schr?dinger equation appropriate to protein obtained from the Davydov theory. The results calculated by this method are basically consistent with the experimental values. Furthermore, the energy spectra at high excited states have also been obtained for the molecular chain which is helpful in researching the properties of infrared absorption and Raman scattering of the protein molecules.

A Novel Resource Allocation Algorithm based on Downlink and Uplink Decouple Access Scheme in Heterogeneous Networks

Traditional cellular network requires that a user equipment(UE) should associate to the same base station(BS) in both the downlink(DL) and the uplink(UL). Based on dual connectivity(DC) introduced in LTE-Advanced R12, DL/UL decouple access scheme has been proposed, which is especially suitable for heterogeneous networks(Het Nets). This paper is the pioneer to take the DL/UL decouple access scheme into consideration and develop a novel resource allocation algorithm in a two-tier Het Net to improve the total system throughput in the UL and ease the load imbalance between macro base stations(MBSs) and pico base stations(PBSs). A model is formulated as a nonlinear integer programming, and the proposed algorithm is a sub-optimal algorithm based on the graph theory. First, an undirected and weighted interference graph is obtained. Next, the users are grouped to let users with large mutual interferences to be assigned to different clusters. Then, the users in different clusters are allocated to different resource blocks(RBs) by using the Hungarian algorithm. Simulation results show that the proposed algorithm can provide great promotions for both the total system throughput and the average cell edge user throughput and successfully ease the load imbalance between MBSs and PBSs.

Exact Solutions of Nonlinear Dynamics Equation in a New Double—Chain Model of DNA

The exact solutions of the general nonlinear dynamic system in a new double-chain model of DNA are studied by using both the Conte's Painlevé truncation expansion and the Pickering's truncation expansion. The symmetric kink-kink shape excitations can be found in both the Conte's truncation expansion and the Pickering's truncation expansion. Three types of new localized excitations, the asymmetric kink-kink excitations, the soliton-kink excitation, and the kink-soliton excitations, are found by using the Pickering's nonstandard truncation expansion.

Generalized Nonlinear Irreducible Auto-Correlation and Its Applications in Nonlinear Prediction Models Identification

There is still an obstacle to prevent neural network from wider and more effective applications, i.e., the lack of effective theories of models identification. Based on information theory and its generalization, this paper introduces a universal method to achieve nonlinear models identification. Two key quantities, which are called nonlinear irreducible auto-correlation (NIAC) and generalized nonlinear irreducible auto-correlation (GNIAC), are defined and discussed. NIAC and GNIAC correspond with intrinstic irreducible auto-(dependency) (IAD) and generalized irreducible auto-(dependency) (GIAD) of time series respectively. By investigating the evolving trend of NIAC and GNIAC, the optimal auto-regressive order of nonlinear auto-regressive models could be determined naturally. Subsequently, an efficient algorithm computing NIAC and GNIAC is discussed. Experiments on simulating data sets and typical nonlinear prediction models indicate remarkable correlation between optimal auto-regressive order and the highest order that NIAC-GNIAC have a remarkable non-zero value, therefore demonstrate the validity of the proposal in this paper.