二元半规范双小波框架滤波器的构造

多元双小波框架的构造由于其较大的自由度和计算的复杂性，一直是小波框架研究内容的难点问题之一。本文提出了一类具有规范滤波器的二元双小波框架的构造方案。具体地，对给定的一对低通滤波器组，利用混合酉扩展原理，首先建立可以生成半规范双小波框架的高通滤波器对的最小数目，然后根据滤波器和多相矩阵之间的关系，给出了构造双小波框架滤波器的具体方案。     

From deep basin gas to diagenetic trap—An example from the Yulin Gas Field in the Ordos Basin

In the updip portion of the Yulin Gas Field in the Ordos Basin, there are no any structural, stratigraphic and sedimentary lithologic seals. Using thin-section petrography, ultraviolet fluorescence microscopy, micro-thermometry and Raman microspectrometry, this paper finds out the diagenetic trap and studies the diagenetic history of this field. It was revealed that three phases of diagenesis and hydrocarbon charging happened in late Triassic, late Jurassic and the end of early Cretaceous respectively. In the first two phases, acid geofluid entered the reservoir and caused dissolution and cementation. Although the porosities had been increased, further compaction accompanying re-subsidence resulted in tight sandstone and conglomerates. Till the end of the early Cretaceous, bulk of gas migrated into the tight reservoir. Cementation, however, kept on in the updip portion of this field due to low gas saturation and formed the diagenetic trap. The mechanism for gas accumulation was changed from deep basin gas to diagenetic trap, which offers a sealing condition that can retain gas for much longer time.     

基于弹性力学的超构材料

近年来以微结构为基本构造单元的人工超构材料,由于具有自然材料所不具备的可设计的奇异物性,在材料学、声学、光学、电磁学以及信息能源等领域具有巨大的发展潜力.超构材料的研究脱胎于电磁超构材料,但是近年来在声学、热学、静电、静磁学以及弹性力学领域取得了飞跃的发展,大大拓展了超构材料的研究领域.借助Milton图重点阐述了基于弹性力学的新型超构材料的超常特性及其主要类别：例如具有负的质量密度和负弹性模量的声学超构材料,具有负泊松比的拉胀超构材料,具有剪切模量G=0的反胀超构材料,以及高强度的超轻材料等新奇的人工超构材料.不仅如此,还结合变换力学着重描述了声波和弹性波在这类弹性力学超构材料中的传播特性,以及详细阐述了负弹性参数超构材料界面的声表面波的特征及其物理效应.最后结合弹性力学超构材料在我国的研究现状,对利用弹性力学超构材料和声波超构材料操纵弹性波和声波的传播以及开发设计新型弹性力学超构材料等问题作了总结与展望,希望推进此类材料在诸多研究领域的应用.     

一种动态的客户端负载均衡机制

互联网应用的并发用户数量不仅多变并且这种变化常常不可预测．将系统容量配置为固定值的惯用做法在面临多变的请求时常常会导致两种结果,一种是因为配置过低而弓l起用户的不满,另一种则因为配置过高而造成计算资源的浪费．而通过运用云架构按需提供、按使用收费的能力,系统具有了实时地按需配置计算资源的能力．然而静态的客户端负载均衡方法作为一种主要的负载均衡技术很难适应云架构条件下更加易变的集群结构．本文提出了一种动态的客户端负载均衡机制．通过引入分布式的集群视图更新、控制流等技术,该机制在保持客户端负载均衡机制分布式、可伸缩性强的基础上,又为集群节点的动态加入与退出和负载均衡策略的动态调整提供了有效的支持．同时,本文分析了该机制在一个开源JEE应用服务器PKUAS中的关键实现问题,并通过实验从多方面验证了该机制的有效性．     

Levels and distributions of polychlorinated naphthalenes in sewage sludge of urban wastewater treatment plants

Over seventy congeners of polychlorinated naphthalenes （PCNs） in sewage sludge of 8 urban waste- water treatment plants （WWTPs） in Beijing were analyzed by isotope dilution, and high resolution gas chromatography/high resolution mass spectrometry （HRGC/HRMS） method, The total PCN concentrations determined in the samples range from 1.48 to 28.21 ng/g dw （dry weight） with TEQ concentrations of 0.11--2.45 pg/g dw. These levels were lower than those found in other regions, DiCNs and TrCNs were the most dominant homologues of PCNs, The similar congener profiles in all the samples suggest the similarity in certain sources, Contamination from industrial input might be the most significant source of PCNs in the sludges in this study, and thermal processes such as waste incineration and coal combustion may be another source of the PCNs contamination.     

Magnetically assisted fluorescence ratiometric assays for adenosine deaminase using water-soluble conjugated polymers

A magnetically assisted fluorescence ratiometric technique has been developed for adenosine deaminase assays with high sensitivity using water-soluble cationic conjugated polymers (CCPs). The assay contains three elements: a biotin-labeled aptamer of adenosine (biotin-aptamer), a signaling probe single-stranded DNA-tagged fluorescein at terminus (ssDNA-Fl) and a CCP. The specific binding of adenosine to biotin-aptamer makes biotin-aptamer and ssDNA-Fl unhybridized, and the ssDNA-Fl is washed out after streptavidin-coated magnetic beads are added and separated from the assay solution under magnetic field. In this case, after the addition of CCP to the magnetic beads solution, the fluorescence resonance energy transfer (FRET) from CCP to fluorescein is inefficient. Upon adding adenosine deaminase, the adenosine is converted into inosine, and the biotin-aptamer is hybridized with ssDNA-Fl to form doubled stranded DNA (biotin-dsDNA-Fl). The ssDNA-Fl is attached to the magnetic beads at the separation step, and the addition of CCP to the magnetic beads solution leads to efficient FRET from CCP to fluorescein. Thus the adenosine deaminase activity can be monitored by fluorescence spectra in view of the intensity decrease of CCP emission or the increase of fluorescein emission in aqueous solutions. The assay integrates surface-functionalized magnetic particles with significant amplification of detection signal of water-soluble cationic conjugated polymers. Supported by the “100 Talents” Program of the Chinese Academy of Sciences, and the National Natural Science Foundation of China (Grant No. 20574073)     

Mechanism and operation parameters of a plasma-driven micro-particle accelerator

There is a large amount of micro debris ranging between millimeters and micrometers in space, which has significant influence on the reliability and life of spacecrafts through long-duration integrated impacts and has to be considered in designing a vehicle’s suitability to the space environment. In order to simulate the micro-impacts on exposed materials, a plasma-driven micro-particle accelerator was developed. The major processes, including the acceleration, compression and ejection of plasmas, were mode...     

Nonlinear dynamics of angle-ply composite laminated thin plate with third-order shear deformation

An asymptotic perturbation method is presented based on the Fourier expansion and temporal rescaling to investigate the nonlinear oscillations and chaotic dynamics of a simply supported angle-ply composite laminated rectangular thin plate with parametric and external excitations. According to the Reddy’s third-order plate theory, the governing equations of motion for the angle-ply composite laminated rectangular thin plate are derived by using the Hamilton’s principle. Then, the Galerkin procedure is applie...     

利用地震海洋学方法研究南海东北部东沙海域内孤立波的结构特征

主要利用地震海洋学方法研究了南海东北部东沙海域内孤立波的结构特征,内孤立波的类型是第一模态下沉型,最大振幅有85.5 m.内孤立波自最大振幅所处深度向下,其振幅大体呈线性减小趋势,振幅随深度的减小率为0.2左右.海底对内孤立波的波形会产生一些影响,一方面海底可能会"切割"内孤立波底部,使之出现间断,另一方面海底的"摩擦"会导致近海底的内孤立波处会发育有较多次一级尺度的波动.横向上看,由地震剖面所得到的内孤立波视宽度,需经过一定的校正才能获得真实宽度,本文所研究的两个内孤立波视宽度分别是4.52和3.36 km,校正后的宽度为0.5~3 km.另外内孤立波处存在的垂向噪音反映出内孤立波具有很强的垂向剪切力.内孤立波水平波数谱与GM模型谱的对比研究表明,其能量在低波数段比GM谱大两个数量级左右.