ARM嵌入式系统在纳米操作系统中的应用研究

近年来，随着微纳米科技的迅速发展，机电产品有望向更微观化、高性能化发展，这将促进材料、制造、电子、生物医学、信息等领域新的科学技术出现，在新的科学技术层次上为可持续发展的理论提供物质和技术保障。微纳米科技最终目标是研究和发现微纳尺度物质所具有的新颖的物理、化学和生物学现象与特性。并以此为基础来设计、制作、组装成新的材料、组件或系统，实现与之相应的特定功能，促进新的科学技术发展与变革，这无疑具有十分重要的科学意义和经济价值。而实现这个目标的使能技术便是微纳米尺度下观测、操作和装配的科学方法与相关的技术和装备，因此开展微纳米操作研究具有特别重要的意义。微纳米操作是微纳米制造科学技术的重要内容之一，使用探针模式的机器人化微纳操作方法，实现在微纳米尺度物体的可控操作，对促进我国微纳米科学技术发展具有特别重要的意义。 目前已有的基于探针的纳米技术装置如SPM (Scanning Probe Microscope)是基于探针模式的纳米观测基本装置。在此基础上研究发展的基于探针的纳米操作已成为纳米科技研究的新领域，是目前世界上各国正在大力开发的前沿研究课题。但目前市场上的SPM等纳米观测设备缺乏驱动控制与信息交互功能和开放界面，限制了用户在此基础上开发纳米操作、装配等功能的能力，因而研究具有信息交互能力的、可进行在线操作控制与宏-微-纳观信息交互的纳米操作监控系统，进而发展成具有自动化/机器人化功能的纳米作业系统队纳米科学技术发展、纳米制造的实现无疑具有重要意义。本论文的科研内容是以面向纳米制造的机器人化系统为研究背景，在自主技术的基础上，开展应用ARM嵌入式系统构成纳米作业系统的实时控制器研究。实时多任务的操作控制系统是纳米作业系统的核心技术，可以实时进行基于探针的传感信息采集、状态反馈控制、形貌观测数据生成、作业运动轨迹生成、位置反馈控制等功能的数据处理与实现。本论文重点介绍以SAMSUNG公司的ARM9处理器芯片S3C2410为嵌入式控制器系统的核心，在移植嵌入式Linux作为操作系统的基础上，开发具有实时数据采集与控制指令、通信功能的人机交互界面。基于ARM的实时控制器的研究为探针模式的纳米观测与操作系统开发提供了关键技术，可以提供开放的AFM系统，促进操作型纳米系统的研究与实现，可以保证纳米观测与操作控制的实时性，可以为纳米作业控制方法提供方便的编程、开发功能。本论文主要研究了面向纳米作业的基于ARM嵌入式实时控制器硬件结构及软件系统的研究与开发过程。首先介绍嵌入式系统的基本概念和特点；其次介绍基于SPM模式的纳米操作系统性能与技术特点；第三，根据纳米作业系统的技术功能要求，详细介绍了具有实时多任务管理功能的硬件系统的设计，重点解决核心板和扩展板各部分功能模块的设计；第四，详细介绍了嵌入式Linux操作系统下的应用程序开发模式及开发过程；最后，详细介绍了嵌入式Linux操作系统下的应用程序开发，主要工作是完成SPM纳米操作系统中的ARM开发平台的功能接口模块的调试及Linux系统下多线程技术在本系统中的应用。本次毕业设计已完成ARM开发平台在整个SPM纳米操作系统中要实现的各个功能模块，结合SPM纳米操作系统的实时性问题，进行了ARM开发平台的系统软件架构分析和利用多线程技术的以太网通信实验，在一定程度上提高了纳米操作系统中的实时性和成像质量。

黄东海及朝鲜海峡冰后期陆架沉积物的环境磁学研究

There are four chapters in this dissertation. The first chapter briefly synthesizes the basic theories, methods and present-day applying situation of environmental magnetism. The second chapter probes into the magnetic mineral diagenesis in the post-glacial muddy sediments from the southeastern South Yellow Sea and its response to marine environmental changes, using the muddy sediment of Core YSDP103 formed in the shelf since about 13 ka BP. The third chapter illustrates the high-resolution early diagenetic processes by investigating the rapidly deposited muddy sediments during the last 6 ka in Cores SSDP-102 and SSDP-103 from the near-shore shelf of Korea Strait. The fourth chapter presents the results of detailed rock magnetic investigation of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea in an attempt to provide environmental magnetic evidence for the provenance of the fine-grained deposit. Core YSDP103 was retrieved in the muddy deposit under the cold eddy of the southeastern South Yellow Sea, and the uppermost 29.79 m core represents the muddy sediments formed in the shelf since about 13 ka BP. The lower part from 29.79 to 13.35 m, called Unit A2, was deposited during the period from the post-glacial transgression to the middle Holocene (at about 6 ~(14)C ka BP) when the rising sea level reached its maximum, while the upper part above 13.35 m (called Unit Al) was deposited in a cold eddy associated with the formation of the Yellow Sea Warm Current just after the peak of post-glacial sea level rise. For the the uppermost 29.79 m core, detailed investigation of rock-magnetic properties and analyses of grain sizes and geochemistry were made. The experimental results indicate that the magnetic mineralogy of the core is dominated by magnetite, maghemite and hematite and that, except for the uppermost 2.35 m, the magnetic minerals were subject to reductive diagenesis leading to significant decline of magnetic mineral content and the proportion of low-coercivity component. More importantly, ferrimagnetic iron sulphide (greigite) is found in Unit A2 but absent in Unit Al, suggesting the control of marine environmental conditions on the magnetic mineral diagenesis. Magnetic parameters show abrupt changes across the boundary between the Unit Al and A2, which reflects a co-effect of environmental conditions and primary magnetic components of the sediments on the diagenesis. Alternating zones of high and low magnetic parameters are observed in Unit A2 of Core YSDP103, which is presumably due to periodic changes of the concentration and/or grain size of magnetic minerals carried into the study area. Cores SSDP-102 and SSDP-103, two studied sediment cores from the Korea Strait contain mud sequences (14 m and 32.62 m in thickness) that were deposited during the last 6,000 years. Analyses of grain sizes and geochemistry of the cores have demonstrated that the sediments have uniform lithology and geochemical properties, however, marked down-core changes in magnetic properties suggest that diagenesis has significantly impacted the magnetic properties. An expanded view of early diagenetic reactions that affect magnetic mineral assemblages is evident in these rapidly deposited continental shelf sediments compared to deep-sea sediments. The studied sediments can be divided into four descending intervals, based on magnetic property variations. Interval 1 is least affected by diagenesis and has the highest concentrations of detrital magnetite and hematite, and the lowest solid-phase sulfur contents. Interval 2 is characterized by the presence of paramagnetic pyrite and sharply decreasing magnetite and hematite concentrations, which suggest active reductive dissolution of detrital magnetic minerals, the absolute minimum abundance of magnetite is reached at the end of this interval. Interval 3 is marked by a progressive loss of hematite with depth, and at the base of this interval, 82% to 88% of the hematite component was depleted and the bulk magnetic mineral concentration was reduced to the lowest value in the entire studied mud section. Interval 4 has an increasing down-core enhancement of authigenic greigite, which is interpreted to have formed due to arrested pyritization resulting from consumption of pore water sulfate with depth. This is the first clear demonstration from an active depositional environment for a delay of thousands of years for acquisition of a magnetization carried by greigite. This detailed view of diagenetic processes in continental shelf sediments suggests that studies of geomagnetic field behavior from such sediments should be conducted with care. Paleoceanographic and paleoclimatic studies based on the magnetic properties of shelf sediments with high sedimentation rates like those in the Korea Strait are also unlikely to provide a meaningful signature associated with syn-depositional environmental processes. The rock magnetic properties of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea, an area surrounded by sands, are investigated with a view to providing information on the sediment provenance. Multiple magnetic parameters such as magnetic susceptibility (%), anhysteretic remanent magnetization (ARM), saturation rernanent magnetization (SIRM), coercivities of SIRM (Her), and S ratios (relative abundance of low-coercivity magnetic minerals) are measured for all 179 surface samples, and partial representative samples are examined for their magnetic hysteresis parameters, temperature-dependence of magnetic susceptibility and x-ray diffraction spectra. Our research indicates that the magnetic mineralogy is dominated by magnetite with a small amount of hematite and is primarily of pseudo-single domain (PSD) to multidomain (MD) nature with a detrital origin. In the surface sediments, the granulometry of magnetic fractions is basically independent of grain sizes of the sediment containing the magnetic grains, and the composition of magnetic minerals remains almost homogeneous, that is, with a relatively constant ratio of low to high coercivity fraction throughout the area. The magnetic concentration in the study area generally decreases to the east or southeast accompanied by magnetic-particle fining to the east or to the northeast. The geographic pattern of magnetic properties is most reasonably explained by a major source of sediment jointly from the erosion of the old Huanghe River deposit and the discharge of the Changjiang River. The rock magnetic data facilitate understanding of the transport mechanism of fine-grained sediments in the outer shelf of the East China Sea.

西北太平洋某海域40ka来的地磁场相对强度研究

Paleointensity changes of geomagnetic field help us to understand the evolutionprocess of earth completely and provide further constraints for earth interior process and geodynamo model. Marine sediments are good carriers for relative paleointensity of geomagnetic field. But in most cases, deep sea sediments that conform with magnetic "uniformity" usually have low sedimentation rate about l-2cm/ka and lie under the Carbonate Compensate Depth with little carbonate content. Therefore, the number of relative paleointensity records with detailed oxygen stratigraphy is still rare. This thesis focus on four cores from east of Ryukyu Trench which have foraminiferal content of 5-30% and sedimentation rate of lOcm/ka and wish to get centennial -millennial changes of relative paleointensity.The sediments from east of Ryukyu Trench conform with magnetic "uniformity" and remanences of four cores all show single component with stable direction and faithfully record the magnetic field. The NRM301T1T/ARM and NRMsomT/ x are still affected by grain size and concentration changes although the sediments are "uniform" , indicating the uniformity might not enough for relative paleointensity. After renomalized by grain size parameter MDF, the intensities remove the effect of grain size changes to different degrees and show coherency in 1-1 Oka scale with results from ODP983/984. The characteristics of paleointensity of geomagnetic field arefrom 32-24kaBP, paleointensity of geomagnetic field is low;24-12kaBP, paleointensity of geomagnetic field is high and shows two peaks boundary with 19kaBP.3) 12-5.3ka, paleointensity is low. Then increase from 5,3kaBP until a small trough at 2.7kaBP, then increase till now.