不可分对称正交小波紧框架的构造

与可分小波相比,不可分小波更能捕捉高维信号的高频信息,正交框架在处理高维信号时能避免预滤波.为了更有效地处理高维信号,本文研究了不可分正交小波紧框架的构造,提出了一种由一维小波紧框架来构造高维不可分正交小波紧框架的方法,即先用张量积的方法构造高维小波紧框架,然后乘上一个具有一定性质的三角多项式.如果一维小波紧框架是对称的,用本文提出的方法构造的高维不可分的正交小波紧框架也是对称的.最后给出了一个构造算例.     

紧支撑正交复小波的参数化

近年来,紧支撑对称正交复小波被广泛应用到不同领域。本文给出一简单的方法对紧支撑的正交复小波进行参数化。该方法可以用来构造一类紧支撑、满足高阶求和法则的正交实值或复值小波。最后给出了具有不同性质的正交复小波的构造例子。     

紧支撑正交小波的构造

给出了尺度因子α=4时，紧支撑正交小波构造的方法，根据所提供的方法构造出一个紧支撑正交小波，该小波具有较小的支撑区间。     

紧支集正交小波基的构造

分析了小波变换及其多尺度分析方法的基本性质，揭示了有限长双尺度方程在紧支集小波基构造中的重要地位，并从正交共轭滤波器的构造入手，提出了一种紧支集正交小波基的构造方法，构造出一系列特性不同的紧支集正交小波基。文章给出了一组性质较好的共轭滤波器系数，并就Ｎ＝４的情况对两种小波基的性质进行了对比分析。     

紧支撑二元正交小波

高维小波是处理多维信号的有力工具,张量积小波有其自身的缺点.本文给出构造矩阵伸缩为2I的紧支撑二元正交尺度函数的一种算法,得到相应的小波函数.当参数l1,l2不全为零时,构造出的小波函数为不可分的,最后给出算例.     

一类向量值正交小波的构造算法

引进向量值多分辨分析与向量值正交小波的概念。运用矩阵理论与仿酉向量滤波器理论,给出了向量值正交小波存在的充要条件。提供了一类紧支撑向量值正交小波的构造算法。     

一种紧支集双正交小波基的构造

基于对偶尺度函数及对偶小波，提出了一种构造紧支集双正交小波基的算法，并给出严密的证明和推导过程。应用该算法，结合函数优化方法，构造出一系列包括样条小波、接近正交的双正交小波及其它具有特殊性质的双正交小波。该构造算法丰富了小波理论，可以广泛应用于信号分析、图像处理等领域。     

正交复滤波器与小波的数值构造

研究了参数化正交复滤波器与小波的数值构造方法.在以往研究成果的基础上,建立了构造正交复滤波器的蝶形算法,该算法便于计算任意长度紧支集复滤波器,便于优化参数设计所需的滤波器与小波.并且研究了参数变化与复滤波器性质的关系,给出相关定理并加以证明.最后给出不同参数下复滤波器、复尺度函数和复小波的计算实例,通过参数优化得到具有对称性和近似线性幅频特性的复小波函数.     

一类紧支撑对称双正交小波(英文)

摘要:研究伸缩因子为3紧支撑对称双正交小波的构造问题.任给一个插值对称的加细函数,本文提供 一个构造其对偶尺度函数的迭代算法,其对偶尺度函数的正则性可以达到任意水平,讨论了它的一些性 质,如对称性和衰减性.最后,给出构造算例.     

半正交小波包

给出紧支撑多元半正交小波包的构造算法。该小波包的特点是：分解系数的选取具有多样性，并且该小波包是基本小波包推广的广义小波包。利用该小波包可使L^2(R^s)中小波基的选择更灵活。     

${\mathbb{Z}}$ 上框架小波包的构造方案及算法实现（英）

为了进一步推动小波理论的应用,近些年来在离散数据环境中开始了对框架小波（也称为framelets）和框架小波包的研究工作．在$\ell^2(Z)$中构造$J$-级框架小波包的方法已经由鲁大勇和易华给出．然而,如何去使用这类小波包的细节却没有给出．为了进一步丰富由鲁和易提出的$J$-级框架小波包理论体系,该文给出了快速的分解和重构算法,运用该算法可以建立不同尺度层之间小波框架系数的关系．另外,为了方便该类框架小波包的应用,文中给出了$\ell^2(Z)$中一些实用框架小波包的具体数据．文中最后通过一个数值实验展示了该类框架小波包的完美重构性质．     

Graphene nanomesh-based devices exhibiting a strong negative differential conductance effect

Using atomistic quantum simulation based on a tight binding model, we have investigated the transport characteristics of graphene nanomesh-based devices and evaluated the possibilities of observing negative differential conductance. It is shown that by taking advantage of bandgap opening in the graphene nanomesh lattice, a strong negative differential conductance effect can be achieved at room temperature in pn junctions and n-doped structures. Remarkably, the effect is improved very significantly (with a peak-to-valley current ratio of a few hundred) and appears to be weakly sensitive to the transition length in graphene nanomesh pn hetero-junctions when inserting a pristine (gapless) graphene section in the transition region between n and p zones. The study therefore suggests new design strategies for graphene electronic devices which may offer strong advantages in terms of performance and processing over the devices studied previously.     

Comparison of curing compounds to reduce volume change from differential drying in concrete pavement

Curing compounds are used to retain moisture which promotes hydration to develop a tight microstructure. Because of the large surface-to-volume ratio of these structures, differential moisture loss can cause unwanted deflections, reduction in ride quality, and cracking. This paper quantitatively compares the effectiveness of different curing methods with an emphasis on curing compounds to resist moisture loss and subsequent volume changes caused by differential shrinkage. This work provides a quantitative comparison between different curing compounds, wet, sealed and no curing not made in previous publications. A performance-based cost analysis over the different curing compounds is also included. The result shows that the poly-alphamethylstyrene curing compound causes the lowest mass loss and subsequent deflections compared to the water–resin and water–wax-based curing compounds at equal coverage rates at equal costs. The work also shows that a double application of curing compound shows greater benefit than a single layer with the same volume for water–wax-based curing compounds. The results show that if adequate amounts of curing compounds are used then they are a useful curing method for members sensitive to differential drying such as concrete pavements.     

中美致密砂岩气成藏分布异同点比较研究与意义

致密砂岩气已成为全球非常规天然气勘探的重点领域。中国致密砂岩气分布范围广,目前已在鄂尔多斯、四川等盆地实现了规模开发;美国落基山地区是致密砂岩气十分发育和勘探相对成熟的地区。对比研究中美致密砂岩气的形成条件和成藏特征是加快中国致密气开发利用与开拓勘探思路的有效途径。中国与美国致密气藏对比研究表明,中美致密砂岩气具有以煤系地层为主要烃源岩、储层致密、存在异常地层压力、源储紧邻与气藏大面积分布等共性特征;差异性主要体现在致密气源岩沉积环境与热演化程度,储层非均质性及其致密化因素,气藏纵向和平面分布特征等方面;控制中美致密砂岩气成藏条件和特征差异性的主要因素是沉积盆地性质、沉积环境和后期构造作用。针对中国致密砂岩气的特殊性,加强储层非均质性、优质储层预测、气藏的分布规律的研究以及加强工程技术攻关提高单井累计产量是致密砂岩气勘探开发工作的重点。     

全球致密气勘探开发进展及中国发展趋势预测

致密气已成为全球非常规天然气勘探开发的重要领域之一,特别是美国致密气大规模开发利用,推动了许多国家进行致密气勘探开发的进程。从全球致密气勘探开发进展情况入手,对我国致密气的勘探开发历程、主要致密气田勘探开发成效、发展趋势及对策建议进行了系统研究。研究表明,我国致密气大致经历了三大发展阶段,目前已进入快速发展阶段。近年来在鄂尔多斯盆地上古生界、四川盆地须家河组、塔里木盆地库车深层发现了一批大型致密气田,致密气储量、产量均呈现出快速增长趋势,2011年致密气产量占我国天然气总产量的1/4左右,预计2020年致密气产量比例将进一步提升到1/3左右,成为支撑我国天然气工业快速、健康、稳定发展的生力军。     

TiO2/活性炭复合体的制备及其表征

以活性炭(AC)为载体,采用溶胶-凝胶法制备纳米TiO2/AC复合型催化剂.利用SEM,TG-DTA,XRD,等手段对其组成、结构、尺寸等进行分析和表征,结果表明,该复合材料由碳、钛、氧等3种元素组成,其中TiO2纳米粒子尺寸在2O-50nm之间,比本体TiO2纳米粒子尺寸小;在该纳米复合材料中,活性炭作为载体与TiO2结合牢固,存在着某种化学键,TiO2纳米颗粒间不发生团聚,并且活性炭载体的比表面积变化不大.     

我国致密砂岩气资源潜力、分布与未来发展地位

系统分析了我国鄂尔多斯、四川和塔里木等主要盆地致密砂岩气成藏条件和主控因素,提出斜坡岩性型和深层构造型是两种最重要的致密砂岩气藏。采用多因素叠合法预测有利含气范围,并通过对已知重点致密砂岩气田的解剖研究,刻度出储量丰度、含气面积系数等关键参数,采用类比法来计算主要盆地的致密砂岩气资源量。研究表明,我国致密砂岩气技术可采资源量为9.2万亿～13.4万亿m3,主要分布于含煤系地层的盆地中;致密砂岩气资源开发利用现实性最好,在国家政策扶持和工程技术进步的推动下,再经过10～20年的发展,有望成为我国天然气开发利用的主导资源之一。     

Non-invasive Glucose Measurements Using Wavelength Modulated Differential Photothermal Radiometry (WM-DPTR)

Wavelength-modulated differential laser photothermal radiometry (WM-DPTR) is introduced for potential development of clinically viable non-invasive glucose biosensors. WM-DPTR features unprecedented glucose-specificity and sensitivity by combining laser excitation by two out-of-phase modulated beams at wavelengths near the peak and the baseline of a prominent and isolated mid-IR glucose absorption band. Measurements on water?Cglucose phantoms (0 to 300?mg/dl glucose concentration) demonstrate high sensitivity to meet wide clinical detection requirements ranging from hypoglycemia to hyperglycemia. The measurement results have been validated by simulations based on fully developed WM-DPTR theory. For sensitive and accurate glucose measurements, the key is the selection and tight control of the intensity ratio and the phase shift of the two laser beams.     

鄂尔多斯盆地致密气勘探开发形势与未来发展展望

鄂尔多斯盆地致密气主要分布在上古生界石炭—二叠系,致密气资源量10.37×1012m3,占盆地天然气总资源量的68%,1995年以来先后发现了米脂、乌审旗、大牛地、神木、苏里格5个致密大气田,致密气地质储量3.78×1012m3,目前已进入储量产量快速增长阶段,近5年来储量年均增幅超过5 000×108m3,致密气产量年均增幅30×108m3,建成了以苏里格气田为代表的致密气生产基地,集成创新形成了以全数字地震、优化钻井、储层改造、井下节流、排水采气、数字管理等为核心的致密气勘探开发关键技术,转变发展方式形成了以"标准化设计、模块化建设、数字化管理、市场化运作"为重点的致密气田开发模式,2011年苏里格气田生产致密气137×108m3,成功地向北京、上海、西安、银川、呼和浩特等重点城市供气。综合评价认为:苏里格南部、靖边—高桥、神木—米脂、盆地西南部是近期致密气增储上产的主要地区,预计2015年以前,盆地致密气储量规模将超过4.5×1012m3,致密气产量将达到255×108m3,并持续长时间稳产。     

One- and two-sided assembly line balancing problems with real-world constraints

In this study, we consider balancing problems of one- and two-sided assembly lines with real-world constraints like task or machine incompatibilities. First, we study the one-sided assembly line balancing problem (ALBP) with a limited number of machine types per workstation. Using a genetic algorithm (GA), we find optimal results for real-world instances. A set of larger test cases is used to compare two well-established solution approaches, namely GA and tabu search (TS). Additionally, we apply a specific differential evolution algorithm (DE), which has recently been proposed for the considered ALBP. Our computational results show that DE is clearly dominated by GA. Furthermore, we show that GA outperforms TS in terms of computational time, if capacity constraints are tight. Given the algorithm’s computational performance as well as the fact that it can easily be adapted to additional constraints, we then use it to solve two-sided ALBP. Three types of constraints and two different objectives are considered. We outperform all previously published methods in terms of solution quality and computational time. Finally, we are the first to provide feasible test instances as well as benchmark results for fully constrained two-sided ALB.