研究生知识库

It is well known that high temperature and high pressure water-fluid is widely found in earth’s interior, especially in the crust and upper mantle,the compaction of diagenetic processes, magmatic differentiation, metamorphic dehydration, atmospheric precipitation, plate subduction and seawater seepage and other geological processes all can produce high tepmerature and high pressure water-fluid in the crust, even in the interspace, pores and cracks of rocks in the upper mantle. High temperature and high pressure water-fluid in the interior of the earth is the most effective transmission medium for materials and energy in earth’s interior, it is also the most active chemical reaction medium in the earth, the interaction between it and other materials(minerals, rocks, ores, solid organic matter and melt) inside the earth is the most important ones in the crust and upper mantle, These kinds of interactions seriously restricts the occurrence and development of various thermodynamics and dynamics in the earth.High temperature and high pressure hydrothermal simulation experiment and in situ observation is one of the most important way to understand the high temperature and high pressure water-flow in the earth’s interior, and to know the composition, structure, characteristics and evolution of other materials of earth’s interior under the condition of high pressure hydrothermal environment, they are also the most direct way to reveal the interaction process of high temperature and high pressure water-flow in the earth’s interior with other materials of earth’s interior. In all kinds of high pressure hydrothermal in situ observation technique, the in situ micro-Raman spectroscopy measurement and the in situ microscopic observation are considered to be the most common and most important in-situ technique, the former can reveal composition, microstructure, property and evolution processing of the high temperature and high pressure water-flow and its coexisting phase; the latter can direct show the spatial morphology, position and evolution of water-flow coexisting phase and flow-flow’s interface.Due to the in situ micro-Raman spectroscopy measurement and the in situ microscopic observation in high pressure hydrothermal experiments, even in high pressure hydrothermal-related engineering and industrial production has a very wide range of applications. scientists and engineers in different areas make great effores to research these two types of in situ technologies and achieve good developments. However, making a general survey of various fields, there are still many problems to be solved. These problems are mainly as follows:(1) As the temperature endurance of the general objectives is quite limited, the high temperature pressure vessel docked with objectives due to the structural requirements of the structure usually need to have a certain size and occupy a larger space, so that the current two types of systems can only be taken to build the distant external objective optical path, which led to the Raman signal intensity and white light imaging resolution has been greatly limited.(2) In addition to individual reports, the confocal technique has not been successfully achieved between the in situ micro-Raman spectroscopy measurement system and the in situ microscopic observation system. which makes the excitation of the Raman signal by laser on the sample surface of samples have a great blindness.(3) In order to maximize the strength of the Raman signal and the resolution of the micro-image, the size and space occupied by the high temperature pressure vessel are minimized. However, the small size of the high temperature pressure vessel severely limits the compatibility between these two in situ techniques and other in situ measurement systems.(4) As fluorescence excited by the laser along the optical path greatly increases the background noise of Raman spectrum, so when temperature inside the high pressure vessels higher than 350℃，it is difficult to get the ideal Raman signal for the in situ Raman measurement systems used in the vast majority of high-pressure hydrothermal vessels All of these defects severely limit the application of these two types of in situ technology in related fields. In order to solve these problems, based on the autoclave experiment system of our laboratory, we developed a set of in-situ microscopic observation and confocal Raman spectroscopy on the basis of mechanical principle, geometric optics, laser physics, Raman spectroscopy, principle of optical design, micro-nano matching, and the high temperature and high pressure experimental geochemistry and hydrothermal autoclave experimental technology principle, the main achievements are as follows:(1)The resolution of our in situ microscopic observation system can reach to 2 microns.(2)The Raman signal obtained by the in situ micro-Raman spectroscopy system we developed in this work have high signal-to-noise ratio, even if the samples measured are at the temperature of 400℃.(3)In this work, we successfully achieve the confocal technique between the in situ micro-Raman spectroscopy measurement system and the in situ microscopic observation system.Thus the in situ micro-Raman spectroscopy measurement system we developed in this work have the function of providing the accurate positioning of Raman signal on the surface of solid samples.(4)The in situ Raman spectroscopy measurement system and the in situ microscopic observation system developed in this work can work under the condition of 600℃ and 100 MPa，and currently it can have worked under the condition of temperature higher than 400℃ and pressure higher than 30 MPa.(5)The in situ Raman spectrum measurement system and in situ microscopic observation system developed in this work can be installed on the pressure vessels for high temperature, it does not interfere with other in situ measurement systems installed on the pressure vessels for high temperature when it works. 

众所周知，高温高压水流体在地球内部尤其是地壳和上地幔广泛存在，沉积物的压实成岩过程、岩浆分异、变质脱水、大气降水、板片封装俯冲以及海水渗流等地质过程均可在地壳甚至上地幔岩石空隙（孔隙和裂隙）中产生高温高压水流体。地球内部的高温高压水流体是地球内部物质和能量最有效的传输介质，同时还是地球内部最活跃的化学反应介质，其与地球内部其它物质（矿物、岩石、矿石、固体有机质和熔体等）间的相互作用是地壳和上地幔最重要的物质间相互作用，该类相互作用严重制约着地球内部各种热力学与动力学过程的发生与发展。高温高压水热模拟实验与原位观测是人们认知地球内部高温高压水流体以及处于高压水热环境中的其它地球内部物质的组成、结构、构造、性状和演化过程最重要的途径之一，同时亦是揭示地球内部高温高压水流体与其它地球内部物质间相互作用过程最直接的研究手段。在各种高压水热原位观测技术中，显微拉曼光谱原位测量和微区白光像原位观察则被认为是最常见和最重要的两种原位技术，前者包含了高温高压水流体及其共存相丰富而细致的物质组成、微观结构、性状和过程信息，后者则直接展示水流体共存相表面以及流体-流体相界面的空间形貌、位置及两者的演化。正由于高温高压显微拉曼光谱原位测量和微区白光像原位观察在高压水热科学实验甚至在与高压水热有关的工程技术和工业生产中具有非常广泛的应用，迄今为止不同领域的科学家和工程师因此在该两类原位技术的研发上付出了不懈努力，也取得了较好的进展但综观各领域现状。但是但综观各领域现状，该两类技术目前仍存在不少亟待突破的瓶颈，主要包括：（1）由于一般的物镜镜头耐受温度相当有限，而对接的高温压力容器由于结构构造的要求通常需具备一定的尺寸和占用较大的空间，从而使得目前该两类系统的搭建基本都只能采取物距较远的外置物镜型光路，由此导致拉曼信号的强度和白光成像的分辨率受到了很大的限制。（2）除极个别报道外，目前已报道研发成功的显微拉曼原位测量系统基本都未实现与白光成像系统两者之间的同聚焦，从而使得激发拉曼信号的激光光斑落在样品表面上的位置有很大的盲目性；（3）为最大限度提高拉曼信号的强度和白光像的分辨率，与之对接的高温压力容器其尺寸和所占空间被要求最小，然而小尺寸的高温压力容器则严重限制了高温压力容器上其它原位测量系统的兼容；（4）由于激光沿光路的荧光激发大大增加了拉曼信号的背景噪音，使得目前绝大多数高压水热拉曼原位测量系统在压力容腔内温度超过约350℃时即难以获得理想的拉曼信号。所有这些缺陷，严重限制了该两类技术的应用场合和在相关领域中发挥的作用。为了解决上述难题，本论文在作者所属实验室已有高压釜实验系统的基础上，基于高压机械、几何光学、激光物理、拉曼谱学、光学零部件设计原理、微纳加工、高温高压实验地球化学以及水热高压釜实验技术等原理，研制出一套可以用于高压釜实验系统的显微拉曼光谱原位测量系统，取得的主要成果如下：（1）本工作研发出的微区白光像原位观察系统其分辨率已高达2微米。（2）本工作中研发出的显微拉曼光谱原位测量系统所获得的拉曼信号即使被测量物温度已超过400 ℃仍具有很好的信噪比。（3）本工作成功实现了显微拉曼光谱原位测量系统与微区白光像原位观察系统两者之间的同聚焦，从而使得本工作中研发出的显微拉曼光谱原位测量系统拥有在固体样品表面定位拉曼信号激发位置的精准定位功能。（4）本工作中研发出的显微拉曼光谱原位测量系统和微区白光像原位观察系统的设计工作温度与压力最高可达600℃、约100 MPa以上，目前实际工作温度与压力已超过400℃、30 MPa。（5）本工作研发出的显微拉曼光谱原位测量系统和微区白光像原位观察系统在高温压力容器上的安装和运行可以兼容在高温压力容器上布局其它原位测量系统，对其它原位测量系统没有排斥作用。