基于FPGA的MDIO总线切换技术

为了在高速图像处理平台特定的网络结构中实现两片DSP与PHY芯片通过一个管理数据输入输出接口(Management Data Input/Output,MDIO)进行通信,利用VHDL语言实现了一个总线切换功能,并设计了一个MDIO总线信号捕获状态机,用该态机的输出来作为双向端口的控制信号,实现了MDIO总线信号在FPGA上实时透明双向传输和两条MDIO总线的实时切换。配合TI公司的网络开发套件,保证了平台正常的网络运行。     

含盐冻结粉质黏土应力-应变关系及强度特性研究

通过对含盐冻结粉质黏土进行三轴压缩试验,分析了该土质在加载至破坏过程中的应力-应变行为,并利用Duncan-Chang双曲线模型求得冻结盐渍粉质黏土的初始弹性模量和偏主应力的最大值。结果表明,初始弹性模量和偏应力最大值随着含盐量的减小和温度的降低而增加。为了分析含盐量对土体强度的作用机制,提出了“相对温度”这一概念,给出相对温度和抗压强度间的线性关系。以一综合指标“相对温度”来考虑盐分、试验温度等多种因素对冻土特性的影响,建立盐渍土和非盐渍土的关系,从而用非盐渍土的力学性质研究盐渍土的力学性质。     

以不完全脱水氯化镁电解制备稀土镁合金的相关技术问题

简述了我国镁和稀土资源的利用情况,以及国内外用电解法制备金属镁和稀土镁合金的情况。详细论述了以不完全脱水氯化镁电解制备稀土镁合金存在的问题、对策以及相关的技术问题。分析了水分及金属氯化物水解产物对电解过程的消极影响及消除方法;讨论了熔盐电解质中金属氯化物与氧化物的转化反应、电解质组成、加料方式、电解槽设计和尾气处理等问题。     

一种基于坡度分析的DEM数字水印算法

提出一种新的基于坡度分析的DEM数字水印算法.该算法以DEM坡度为主要研究对象,由于坡度误差主要集中在平坦地区,而经小波变换后的DEM低频系数信息可反映DEM区域的地形复杂度,因此,通过对DEM低频系数进行分析,可自适应地确定水印的嵌入位置;然后以加性法则将水印信息嵌入低频系数,再经小波逆变换,即可得到含水印信息的DEM数据.实验结果表明,该算法能完全满足水印的不可见性,对DEM数据的高程精度、坡度精度及等高线的提取精度影响都很小,能够满足一定的应用要求,且具有良好的抗噪能力.     

汽车防撞系统中视频图像采集系统的设计实现

提出一种用于汽车防撞系统的快速视频图像采集系统.利用PHILIPS公司的视频处理芯片SAA7111A作为图像采集芯片,在单片机和CPLD的控制下将采集到的图像数据写入帧存储器中供后续DSP对视频数据进行分析处理;针对汽车防撞系统对实时性的要求,帧存储器的设计采用两级级联的形式,达到了采集和数据处理的并行运行.     

The Petrology and Geochemistry of Volcanic Rocks on Jeju Island: Plume Magmatism along the Asian Continental Margin

The incompatible element signatures of volcanic rocks formingJeju Island, located at the eastern margin of the Asian continent,are identical to those of typical intraplate magmas. The sourceof these volcanic rocks may be a mantle plume, located immediatelybehind the SW Japan arc. Jeju plume magmas can be divided intothree series, based on major and trace element abundances: high-aluminaalkalic, low-alumina alkalic, and sub-alkalic. Mass-balancecalculations indicate that the compositional variations withineach magma series are largely governed by fractional crystallizationof three chemically distinct parental magmas. The compositionsof primary magmas for these series, using inferred residualmantle olivine compositions, suggest that the low-alumina alkalicand sub-alkalic magmas are generated at the deepest and shallowestdepths by lowest and highest degrees of melting, respectively.These estimates, together with systematic differences in traceelement and isotopic compositions, indicate that the upper mantlebeneath Jeju Island is characterized by an increased degreeof metasomatism and a change in major metasomatic hydrous mineralsfrom amphibole to phlogopite with decreasing depth. The originalplume material, having rather depleted geochemical characteristics,entrained shallower metasomatized uppermost mantle material,and segregated least-enriched low-alumina alkalic, moderatelyenriched high-alumina alkalic, and highly enriched sub-alkalicmagmas, with decreasing depth. KEY WORDS: Jeju Island; magma genesis; mantle plume; subcontinental mantle     

遥感影像纠正中GCP选取及自动化实现

地面控制点的选取是遥感影像几何纠正中的重要环节。控制点的数量、分布和精度直接影响影像纠正的精度和质量。本文较为系统地总结了控制点选取的诸多要素及注意事项,并对GCP选取的自动化技术进行了探索和实践。     

布曲河特大桥钻孔灌注桩施工工艺

在高原多年冻土地区，气候恶劣，生态环境脆弱，钻孔灌注桩施工中又不可避免地会遇到土层处于不同的冻结状态，施工中必须考虑并设法预防和消除由于冻土的变形、强度弱化及冻胀、融沉所引起的各种病害，因此钻孔灌注桩施工在质量、安全和环保等方面难度很大。介绍了布曲河特大桥钻孔灌注桩施工工艺，该工艺明显不同于内地通常的钻孔灌注桩施工工艺，在高原多年冻土地区是行之有效的，对高原多年冻土区钻孔灌注桩施工具有重要的参考意义。     

遥感影像纠正中控制点库建立相关技术

地面控制点的选取是遥感影像几何纠正中的重要环节。针对人工选取控制点的缺陷,根据控制点数据的特点提出了控制点属性数据和图像数据的一体化存储管理方案;设计了控制点库查询检索、匹配选点的使用流程;实现了一个控制点影像数据库的应用系统。系统的使用效果达到预期设想,大大提高了选点精度和效率。对控制点数据进行建库管理可以充分利用已有控制点成果,并能提高选点效率和精度。     

Characteristics and Dolomitization of Upper Cambrian to Lower Ordovician Dolomite from Outcrop in Keping Uplift, Western Tarim Basin, Northwest China

Late Cambrian to Early Ordovician sedimentary rocks in the western Tarim Basin, Northwest China, are composed of shallow-marine platform carbonates. The Keping Uplift is located in the northwest region of this basin. On the basis of petrographic and geochemical features, four matrix replacement dolomites and one type of cement dolomite are identified. Matrix replacement dolomites include (1) micritic dolomites (MD1); (2) fine–coarse euhedral floating dolomites (MD2); (3) fine–coarse euhedral dolomites (MD3); and (4) medium–very coarse anhedral mosaic dolomites (MD4). Dolomite cement occurs in minor amounts as coarse saddle dolomite cement (CD1) that mostly fills vugs and fractures in the matrix dolomites. These matrix dolomites have δ18O values of ?9.7‰ to ?3.0‰ VPDB (Vienna Pee Dee Belemnite); δ13C values of ?0.8‰ to 3.5‰ VPDB; 87Sr/86Sr ratios of 0.708516 to 0.709643; Sr concentrations of 50 to 257 ppm; Fe contents of 425 to 16878 ppm; and Mn contents of 28 to 144 ppm. Petrographic and geochemical data suggest that the matrix replacement dolomites were likely formed by normal and evaporative seawater in early stages prior to chemical compaction at shallow burial depths. Compared with matrix dolomites, dolomite cement yields lower δ18O values (?12.9‰ to ?9.1‰ VPDB); slightly lower δ13C values (?1.6‰–0.6‰ VPDB); higher 87Sr/86Sr ratios (0.709165–0.709764); and high homogenization temperature (Th) values (98°C–225°C) and salinities (6 wt%–24 wt% NaCl equivalent). Limited data from dolomite cement shows a low Sr concentration (58.6 ppm) and high Fe and Mn contents (1233 and 1250 ppm, respectively). These data imply that the dolomite cement precipitated from higher temperature hydrothermal salinity fluids. These fluids could be related to widespread igneous activities in the Tarim Basin occurring during Permian time when the host dolostones were deeply buried. Faults likely acted as important conduits that channeled dolomitizing fluids from the underlying strata into the basal carbonates, leading to intense dolomitization. Therefore, dolomitization, in the Keping Uplift area is likely related to evaporated seawater via seepage reflux in addition to burial processes and hydrothermal fluids.