一种基于SPIHT的分层图像压缩方法

提出一种利用SPIHT算法进行图像分层压缩的编码方法,该方法首先利用图像平滑技术将图像分解为平滑部分和轮廓部分,然后以一定的编码率分别对它们进行编码.实验结果表明,合理分配各层的编码率,能够获得视觉效果比单独采用SPIHT编码更好的编码图像.     

Effects of hyaluronic acid－chitosan－gelatin complex on the apoptosis and cell cycle of L929 cells

With the development in the field of tissue engineering, the interaction between biomaterials and cells has been deeply studied. Viewing the cells seeded on the surface of materials as an organic whole, cell cycle and apoptosis are analyzed to deepen the study of cell compatibility on biomaterials, while cell proliferation and differentiation are studied at the same time. In this paper, hyaluronic acid is incorporated into the chitosan-gelatin system. Propidium iodide (PI) was used in cell cycle analysis and the double-staining of cells with annexin-V and PI was applied in cell apoptosis analysis. The results show that incorporated hyaluronic acid shortens the adaptation period of cells on the material surface, and then cells enter the normal cell cycle quickly. In addition, added hyaluronic acid inhibits cell apoptosis triggered by the membranes. Therefore, hyaluronic acid improves the cell compatibility of chitosan-gelatin system and benefits the design of biomimetic materials.     

Evolution of the South China Sea and monsoon history revealed in deep-sea records

As the third summary report of ODP Leg 184 to the South China Sea (SCS), this paper discusses the evolution of the East Asian monsoon and the SCS basin. A multi-proxy approach, involving geochemistry, micropale-ontology, pollen and other analyses, was adopted for reconstructing the evolutionary history of the East Asian monsoon, which was characterized by a series of paleo-climate events especially at 8, 3.2, 2.2 and 0.4 Ma. The new record indicates similar stages in the development of the East and South Asian monsoons, with an enhanced winter monsoon over East Asia being the major difference. The rich spectrums of monsoon variability from the southern SCS also reveal other characteristic features of the low latitude ocean. Evidence for the evolution of the SCS includes the hemipelagic Oligocene sediments, implying the existence of deep water environments during the early seafloor spreading stage of the SCS basin. The four major unconformities and some remarkabl ediagenetic features in upper Oligocene deposits indicate the strongest tectonic events in the region. From a careful comparison of lithologies and sedimentation rates, we conclude that the prominent differences in sedimentary environments between the southern and northern SCS were established only by ～3 Ma.     

低含水率沙床的临界起沙风速

针对目前对风沙起动机制的认识有限的现状，采用量钢分析法推导出对湿沙床的起沙有影响的4个无量纲数。经分析得到起沙风速与沙床沙粒粒径和沙床粘结力间的数量关系。通过建立沙床粘结力与含水率、沙粒粒径的关系式，得到临界起沙风速和沙粒粒径，含水率间的定量关系式。认为低含水率沙床的风沙起动风速与颗粒粒径的一次方和沙床含水率的1／4次方成线性关系，此结论与前人的实验结果符合得很好。     

在Newman型结点上Lagrange插值多项式的发散性

191 8年 ,Bernstein证明了对于函数 |x|,由闭区间 [-1 ,1 ]上的等距结点所构成的 Lagrange插值多项式序列 ,除了 -1 ,0 ,1以外 ,在闭区间 [-1 ,1 ]上的其他任何点都发散 .1 995年 ,L.Brutman和 E.Passow将Bernstein的结论推广到一类 Newman型的结点上 .本文考虑了比 |x|更好性质的函数 ,它的 Lagrange插值多项式仍旧处处发散 ,进一步指出了 |x|的发散性并不是孤立的现象 .     

基于等距结点的Lagrange插值多项式在零点的收敛速度

S.M.Lozinskii指出了函数 |x|基于等距结点的 Lagrange插值多项式在零点的收敛速度 .2 0 0 0年 ,M.Revers把 S.M.Lozinskii的结果推广到 |x|α( 0 <α≤ 1 ) .在此中考虑了α>1的特殊情况 f ( x) =|x|5,对其基于等距结点 Lagrange插值多项式在零点收敛速度进行估计     

墙梁计算方法

本文通过某工程实例的计算，充分表达了新规范中墙梁计算的原理与方法。这对于广大设计人员正确计算墙梁将起到一定指导作用     

论地质体几何造型

首次提出了地质体几何造型的概念及地质体建模的几何造型方法．运用几何造型技术和方法，导出了各种地质体（点状、线状、面状和复杂）的几何造型模型，这些模型包括地质体的几何、属性和拓扑3个方面的信息，可完整地实现地质体的信息存储、模型构造、几何分析、图形表达与构型运算．地质体几何造型从理论上和方法上解决了地学各领域中的基础性问题──地质体的模型构造和表示．长期以来未取得任何进展的地测图件自动生成难题的解决即是其实例之一．     

地质体几何造型应用

作者提出的地质体几何造型理论和方法实现了地质体的信息存储、模型构造、几何分析与图形表达，可应用于涉及地质体形态的各个地学领域（构造地质、矿床地质、矿床勘探、矿山开采等）．地测图件自动生成系统AutoGDPS的开发成功是其典型应用．基于地质体几何造型理论和方法，通过矿体边界人工圈定和勘探线剖面图手工编绘过程分析，将勘探剖面图等地测图件中各种地质体及工程元素（如断层基点、钻孔、矿带边界线、矿体、储量分析）表述为相应的地质体几何造型模型，进而给出了矿体边界自动圈定和勘探线剖面图自动生成的基本过程、定量准则和几何造型模型的建立方法，其成果AutoGDPS已应用于攀钢集团朱矿、兰矿、设计研究院和生产处等单位的生产中，大幅度地提高了地测工作效率．