利用重磁异常场研究东海深部构造

基于布格重力异常数据和磁力异常数据分析,研究了东海地区的深部构造。研究表明,东海地区的布格重力异常主体有正异常背景,局部有些负值重力低圈闭,异常幅值在-160~460mGa之间变化,走向以NE,NNE向为主体走向;东海地区磁力异常主体呈异常正负交替的特征,主体走向为NE向,磁异常值在-200~+500nT之间变化。对重磁异常数据进行了向上延拓数据处理工作,去掉了浅部的异常,深部构造明显。根据重磁异常综合分析,东海深部构造自西向东依次为浙闽隆起带、东海陆架盆地、钓鱼岛隆褶带、冲绳海槽盆地、琉球隆褶带和菲律宾海盆地。     

一种抑制EMD端点效应新方法及其在信号特征提取中的应用

经验模式分解(EMD)的端点效应一直是困扰其工程实用性的难点问题,结合端点效应产生机理和现有的研究成果,提出了一种基于端点优化对称延拓(End Optimization Symmetric Extension,EOSE)的抑制EMD端点效应新方法.通过对信号和其包络线的偏差评价函数的最小化计算,获取最佳的信号端点值,在此基础上延拓信号的上、下包络线将最大化地逼近原始信号两端点,在EMD后续"筛选"固有模态分量(IMF)过程中抛弃两端延拓的数据,将端点效应释放到原始信号的以外.将原EMD、基于EOSE改进EMD和基于时间序列建模(ARMA)改进EMD3种方法进行对比分析,仿真和实验结果表明,基于EOSE方法抑制EMD端点效应的效果最好,能够精确提取出旋转机械振动信号的典型故障特征,运算效率较高.     

风道结构对地板下送风型数据中心气流组织的影响(1)数值设计

本文以排布奇数列机柜冷通道封闭的数据中心子模块为研究对象(3列机柜为例),采用CFD模拟将静压层高度与地板穿孔率对数据中心气流组织的联合影响进行可视化,并分析了两种参数组合的25个典型模型的温度场,选出最佳静压层高度与地板穿孔率的范围分别为600~700 mm,20%~50%。对比了最佳静压层高度与地板穿孔率组合范围内的8个数据中心气流组织模型,选出机柜内部温度分布较均匀的气流组织模型。在此基础上,在静压层内架设挡板,并在-15°~45°的挡板角度中选择最佳角度以获得最优冷却效果。结果表明:静压层高度为600 mm,穿孔地板穿孔率为20%,设置15°挡板的数据中心子模块为最优模型。     

营口-宽甸地区里尔峪组地层的T△磁场分析及远景预测

通过对区域磁场特征与矿产分布关系的研究发现：铁、硼矿产分布在区域异常带内或其边部的位置。根据za分量上延拓800米（从飞行高度算起）的磁异常带的特征和铁、硼矿产及局部磁异常的分布,大致划分为八个“蕴矿区”。同时,用统计的方法,对局部磁异常进行了筛选,共筛选出六个局部异常,提出了今后区域性普查找矿工作的重点工作区域;同时提出了找寻硼、铁矿产的具体地区。     

登月飞行器软着陆发动机持续工作初始点选择研究

完成了推力幅值恒定的登月飞行器时间最优和燃料最优的软着陆轨道研究。文中将飞行器在月球表面软着陆的轨道分为开普勒下降轨道和制动发动机持续工作轨道两个阶段进行了综合研究。并着重研究了当飞行器从高度为100km的轨道下降到15km近月点时,在近月点附近是否存在一点,在该点软着陆发动机开始持续工作能够更加节省燃料。     

PDLLA/PCL共混医用材料的表面形貌和防粘连性能研究

采用熔融共混制备了5种聚乳酸(PDLLA)/聚己内酯(PCL)共混医用材料,并进行挤出流延制备薄片。采用原子力显微镜研究薄片的表面形貌和截面高度曲线,与纯PDLLA相比,共混物的表面相对光滑、截面高度曲线振幅减小,最高凸起从800 nm下降到180 nm以下。PCL的加入提高了共混物的表面平整度,获得更加光滑的外观,原因在于分子量相对较小的PCL产生润滑和增塑效应所致。PCL含量为30%时共混物的柔性较好、半衰期为90 d,与肌腱手术的临床要求相匹配,适合用于制备肌腱吻合器。细胞培养实验表明,成纤细胞在PDLLA/PCL(70/30)共混物薄片表面的数量很少,说明其不容易粘附在材料表面,具有较好的防粘连作用。     

基于“云预算”的高校专项资金项目库管理系统构建的研究

云预算在企业财务数据分析中有重要的作用,从会计电算化情况的来看,大多数高校存在人力物力资源消耗大、系统效率低以及智能化程度不高等问题。因此,该文提出基于“云预算”的高校专项资金项目库管理系统构建的研究,采用神经网络和数据挖掘方法对高校异常数据进行监测处理,其中采用数据挖掘对财务数据处理,对高校专项项目信息进行筛选,并对数据进行标准化处理,进而解决高校专项资金项目管理消耗大的问题。同时,采用神经网络算法对异常数据进行识别,加强对高校专项资金异常数据预警。结果表明：云预算具有效率高、智能程度高以及成本低等特点,云预算能在高校专项资金项目库管理系统上对异常数据进行识别,监测正确率能达到90%以上,证明了云预算的有效性。     

基于PIV的大豆蛋白液双枪喷涂速度场的研究

目的 为了在保证喷涂雾化表征均匀性的前提下实现宽幅覆膜,提高覆膜的效率,以期得到均匀一致的大豆蛋白覆膜。方法 利用粒子图像速度场仪（Particle Image Velocimetry,PIV）,对不同干涉程度下的大豆蛋白液双枪喷涂雾化场进行拍摄,利用PIV和Origin软件处理图像,得到速度数据并对比。结果 随着双枪间偏转角的增大,基线上的平均速度减小;偏转角为0°时,两喷雾粒子流在干涉线处碰撞,少有透过干涉线的粒子;在不同偏转角下,基线上的速度峰值从大到小为偏转角7°时的速度峰值、偏转角0°时的速度峰值、偏转角15°时的速度峰值;当偏转角为0°时,随着液压的增大,基线上的第2个速度谷值会右移,并且会增大直至消去。结论 当偏转角为0°、液压为0.24 MPa时,在基线上干涉区域内的速度最均匀。     

利用超声波图像检测提取钻孔参数

利用超声波对钻成孔进行检测,可以直观地给出钻孔的垂直度、孔径等参数。但是,目前的超声波钻孔检测设备只能给出钻孔的观测图像,而要得到孔径和垂直度等参数,需要从回放的数据中读取（比如中科院东海研究站研制的UDM100Q钻孔检测仪）,或从打印输出的图纸上测量（比如进口的超声波钻孔检测仪）。通过对超声波成孔检测记录图用数字图像处理方法进行处理,提取出钻孔的孔壁线,并使其坐标映射到实际测量的坐标范围,从而能通过提取壁线的坐标计算出孔径、垂直度等参数。     

近海山地台风风场特性实测研究

基于2017年台风“海棠”和台风“纳沙”登陆近海山地时的实测数据,选取10 min平均风速≥10 m/s的强风样本,研究了平均风速、湍流度、阵风因子和地面粗糙度指数的变化规律,并分析了不同风速区间的风剖面和湍流剖面的变化规律。结果表明:台风登陆过程中风速时程呈双“M”型四峰分布,平均风向发生了260°的转变,10 m高度处湍流强度在0.15~0.34波动,并随地貌粗度指数增大有增大的趋势。实测得到风剖面和湍流剖面与规范GB 50009?2012进行了对比,不同高度处的平均风速变化符合指数率的变化趋势;两个测风塔实测得到台风风场的风剖面指数α均值为0.15和0.14大于季风风场的风剖面指数,接近GB 50009?2012中B类地貌规定值,但台风风场中的湍流强度剖面参数要大于GB 50009?2012中B类地貌规定参数值,该文结果可为近海山区工程结构抗台风设计提供参考。     

具有两个偏差变元的Rayleigh方程的周期解的存在性

本文研究了一类具有两个偏差变元的Rayleigh方程的T-周期解的存在性问题.这是首次针对该类方程在其阻尼项满足Lipschitz条件的情况下进行的研究工作.通过一个改进的先验估计、运用一些分析技巧并利用迭合度的延拓定理,我们获得了方程存在周期解的新的结果.     

DGH方程的持久性和唯一连续性

本文研究了DGH方程的持久性和唯一连续性.我们证明:如果DGH方程的强解与它的空间导数在初始时刻指数递减,而且在以后的任一时刻解本身也指数递减,那么解必然恒为零.     

Continuous design transmutation method for problems in engineering analysis

Many problems in engineering analysis and design involve searching solutions of a system of equations. In most cases, because these equations are highly coupled and non‐linear and thus unlikely to yield close‐form solutions, researchers seek possible solutions using numerical techniques. In this paper, we present a ‘Continuous Design Transmutation Method’, a numerical method based on the polynomial continuation theory that has been discussed in recent works appearing in engineering literature. Our model departs from similar approaches in that its start system and homotopy are based on physical design and not pure mathematical equations. To avoid singularity on real paths, we introduce a heuristic disturbance mechanism. First, we simplify target design in order to construct a design that possesses both a similar structure and known solutions. Then, we construct a homotopy between the governing equations of the simplified design and those of the target design. The solutions of the target problem emerge as one tracks the solutions of the simplified design's governing equations as these incrementally evolve from the simplified design into the target design. Using our method, one tracks only isolated solutions of the simplified problem. All of the extraneous paths have been eliminated before the solution‐tracking procedure begins. As a result, not only can one easily interpret, in physical terms, the transmutation process, but one can also monitor the design feature changes. In this paper, we demonstrate our method as applied to two sample problems: a five‐point position‐generation problem for a planar four‐bar mechanism and a function‐generation problem for an RSSR linkage. Copyright © 2004 John Wiley & Sons, Ltd.     

An exact thermopiezoelasticity solution for a three-phase composite cylinder

An exact solution is first derived for the stress field in a three-phase piezoelectric composite cylinder induced by a uniform heat flux together with an anti-plane shear and in-plane electric field applied at infinity. Based on the method of analytical continuation in conjunction with the alternating technique, the general expressions of the temperature and stress functions are derived explicitly in each medium of a three-phase composite cylinder. It is discovered that the stress and the electric displacement in the inclusion is always linearly proportional to the coordinate. The numerical results demonstrates that the continuity conditions at the interface are indeed satisfied and shows the effects of material mismatch on the stress and electric displacement fields.     

Handling high-dimensional problems with multi-objective continuation methods via successive approximation of the tangent space

In many applications, several conflicting objectives have to be optimized concurrently leading to a multi-objective optimization problem. Since the set of solutions, the so-called Pareto set, typically forms a (k?1)-dimensional manifold, where k is the number of objectives considered in the model, continuation methods such as predictor–corrector (PC) methods are in certain cases very efficient tools for rapidly computing a finite size representation of the set of interest. However, their classical implementation leads to trouble when considering higher-dimensional models (i.e. for dimension n>1000 of the parameter space). In this work, it is proposed to perform a successive approximation of the tangent space which allows one to find promising predictor points with less effort in particular for high-dimensional models since no Hessians of the objectives have to be calculated. The applicability of the resulting PC variant is demonstrated on a benchmark model for up to n=100, 000 parameters.     

Revisit of an elliptic hole problem by using complex variable method

In this paper, the problem of an elliptic hole embedded in an infinite plate interacting with an arbitrary point load is revisited by using the complex variable method. Based on analytical continuation theorem, the continuity conditions across the interface are automatically satisfied in a straightforward manner. It is shown that the solution for an infinite domain with an elliptic hole can be obtained from the solution of the corresponding homogeneous problem merely by a simple algebraic expression. This relation is universal in the sense of being independent of the loading considered. The solution of the corresponding homogeneous problem is considered as the principal part of the complex potentials while the complementary part of the complex potentials can be obtained by using analytical continuation theorem. Different expressions of the complementary part of the complex potentials are presented in this paper which are all proved to be the same result.     

On the continuation of the limit distributions of the extreme and central terms of a sample

We consider the situation where the distribution functions (d.f.'s) of the suitably normalized extreme and central order statistics on an interval [c,d] converge to arbitrary nondecreasing functions. The continuation of these convergences (weak) on the whole real line to the extreme and central value distributions is then proved under general conditions.     

The effect of the small-aspect-ratio approximation on canonical electrostatic MEMS models

The mathematical modeling and analysis of electrostatically actuated micro- and nanoelectromechanical systems (MEMS and NEMS) has typically relied upon simplified electrostatic-field approximations to facilitate the analysis. Usually, the small aspect ratio of typical MEMS and NEMS devices is used to simplify Laplace’s equation. Terms small in this aspect ratio are ignored. Unfortunately, such an approximation is not uniformly valid in the spatial variables. Here, this approximation is revisited and a uniformly valid asymptotic theory for a general “drum shaped” electrostatically actuated device is presented. The structure of the solution set for the standard non-uniformly valid theory is reviewed and new numerical results for several domain shapes presented. The effect of retaining typically ignored terms on the solution set of the standard theory is explored     

Exact solutions of the cubic–quintic Swift–Hohenberg equation and their bifurcations

Many systems of physical interest may be modelled by the bistable Swift–Hohenberg equation with cubic–quintic nonlinearity. We construct a two-parameter family of exact meromorphic solutions of the time-independent equation and use these to construct a one-parameter family of exact periodic solutions on the real line. These are of two types, differing in their symmetry properties, and are connected via an exact heteroclinic solution. We use these exact solutions as initial points for numerical continuation and show that some of these lie on secondary branches while others fall on isolas. The approach substantially enhances our understanding of the solution space of this equation.