高放处置罐铁释放诱发膨润土矿物相变研究进展

作为高放废物处置罐候选金属材料,低碳钢在处置库服役期间,其腐蚀产物侵入缓冲屏障,导致缓冲材料矿物相变与性能变异,威胁多重屏障体系的长期安全稳定。本文详细综述了国内外处置库深部还原环境所处的弱碱性化学场与中低温度场的变化趋势,认为处置库深部化学-温度还原条件可导致处置罐Fe腐蚀释放Fe~(2+)。在处置库长期运行过程中,蒙脱石与Fe~(2+)接触发生矿物相变,一方面Fe~(2+)置换蒙脱石八面体晶格中的Al~(3+)和Mg~(2+),还原Fe~(3+)或直接占据空位,生成次生矿物;另一方面Fe~(2+)交换蒙脱石层间的Na~+、K~+和Ca~(2+),转化为铁基蒙脱石。矿物相变可诱发缓冲屏障性能变异甚至退化。基于\"抗矿物转化\"理念,提出了下一阶段缓冲材料矿物相变研究方向,为地下实验室碳素钢选型、缓冲屏障验证试验设计以及屏障体系安全评价提供科学依据。     

Diffusive wave solutions for open channel flows with uniform and concentrated lateral inflow

The diffusive wave equation with inhomogeneous terms representing hydraulics with uniform or concentrated lateral inflow into a river is theoretically investigated in the current paper. All the solutions have been systematically expressed in a unified form in terms of response function or so called K-function. The integration of K-function obtained by using Laplace transform becomes S-function, which is examined in detail to improve the understanding of flood routing characters. The backwater effects usually resulting in the discharge reductions and water surface elevations upstream due to both the downstream boundary and lateral inflow are analyzed. With a pulse discharge in upstream boundary inflow, downstream boundary outflow and lateral inflow respectively, hydrographs of a channel are routed by using the S-functions. Moreover, the comparisons of hydrographs in infinite, semi-infinite and finite channels are pursued to exhibit the different backwater effects due to a concentrated lateral inflow for various channel types.     

多相离散随机介质模型及其探地雷达波场特征研究

沥青混凝土是由骨料、沥青胶浆、空气按照一定的体积百分比混合而成的多相非匀质混合物, 其骨料、沥青胶浆和空气的体积不等、形状各异、介电特性不同、空间位置随机分布, 具有明显的多相、离散、随机介质特征.本文基于随机介质模型理论, (1)测量与统计了介电常数在典型沥青混凝土芯样空间上的随机分布统计特征; (2)估算了沥青混凝土介质的自相关函数及其特征参数(自相关长度、自相关角度等), 确定其随机介质类型; (3)提出了量化约束下的多相离散随机介质建模算法, 以混合型椭圆自相关函数为基础, 构建了不同粗糙度因子的多相离散随机介质模型; (4)构建了不同空隙率的多相离散随机介质模型, 正演模拟与对比分析了探地雷达波在均匀介质、连续型随机介质和多相离散随机介质中的传播特征.结果表明:多相离散随机介质模型不仅描述了沥青混凝土的多相、离散与空间随机分布统计特征, 而且进一步描述了其各组成物质体积百分比, 能更全面、准确地描述沥青混凝土的介质特征, 同时也为描述其他类似材料或介质提供了新的方法和途径; 在多相离散随机介质模型中, 探地雷达波散射强烈, 随机、无序传播的散射波相互叠加干涉, 形成了明显的随机扰动和"噪声", 致使异常体反射波扭曲变形、不连续, 降低了探地雷达回波的信噪比和分辨率.研究探地雷达波的随机扰动特征与多相离散随机介质模型参数之间的关系, 将为定量评价多相离散随机介质的属性参数提供参考和帮助.     

Two steps forward,two steps back: The role of innovation in transforming towards community-based marine resource management in Solomon Islands

In many coastal nations, community-based arrangements for marine resource management (CBRM) are promoted by government, advocated for by non-government actors, and are seen by both as one of the most promising options to achieve sustainable use and secure inshore fisheries and aquatic resources. Although there is an abundant literature on what makes CBRM effective, is it less clear how CBRM is introduced or develops as an idea in a community, and the process of how the idea leads to the adoption of a new resource management approach with supporting institutions. Here we aim to address this gap by applying an explicit process-based approach drawing on innovation history methodology by mapping and analysing the initiation and emergence of CBRM in five fishing-dependent communities in Solomon Islands. We use insights from the literatures on diffusion of innovation and transformability to define phases of the process and help guide the inductive analysis of qualitative data. We show the CBRM institutionalisation processes were non-linear, required specific strategies to move from one phase to the next, and key elements facilitated or hindered movement. Building active support for CBRM within communities depended on the types of events that happened at the beginning of the process and actions taken to sustain this. Matching CBRM to known resource management ideas or other social problems in the community, developing legitimate institutions and decision-making processes, strong continual interactions between key actors and the rest of the community (not necessarily NGO actors), and community members witnessing benefits of CBRM, all contributed to the emergence and diffusion of CBRM in the communities, and helped to overcome barriers to transformative change.     

运用GPS测量对自贡市城市控制网点的改算

本文通过对运用GPS测量改算自贡市各等级城市控制网点成果的过程及结果的论述分析,证实了运用GPS测量改算城市控制网点成果具有精度好、效率高等特点。在此基础上探讨其可行性,并提出一些看法。     

空间坐标系变换的函数梯度描述方法

为了将空间坐标系变换由静态的、不随时间发生变换的情况推广到动态的、随时间发生变换以及任意角度发生变换的情况,基于单位四元数构造的旋转矩阵和罗德里格矩阵的完全等价性,揭示出空间坐标系（空间直角坐标系）变换与函数梯度的数学关系,推导出由函数梯度表示的空间坐标系变换的数学公式,在理论上说明了用函数梯度描述空间坐标系变换的方法。研究表明：在数学意义上,空间坐标系变换的本质是"场",可以用"场"的概念统一以任意角度发生旋转变换的空间坐标系变换特例。为进一步研究空间坐标系随时间发生连续变换的情况或以新的思路为运动载体定姿奠定了理论基础。     

On the multivariate total least-squares approach to empirical coordinate transformations. Three algorithms

The multivariate total least-squares (MTLS) approach aims at estimating a matrix of parameters, Ξ, from a linear model (Y−E _Y = (X−E _X ) · Ξ) that includes an observation matrix, Y, another observation matrix, X, and matrices of randomly distributed errors, E _Y and E _X . Two special cases of the MTLS approach include the standard multivariate least-squares approach where only the observation matrix, Y, is perturbed by random errors and, on the other hand, the data least-squares approach where only the coefficient matrix X is affected by random errors. In a previous contribution, the authors derived an iterative algorithm to solve the MTLS problem by using the nonlinear Euler–Lagrange conditions. In this contribution, new lemmas are developed to analyze the iterative algorithm, modify it, and compare it with a new ‘closed form’ solution that is based on the singular-value decomposition. For an application, the total least-squares approach is used to estimate the affine transformation parameters that convert cadastral data from the old to the new Israeli datum. Technical aspects of this approach, such as scaling the data and fixing the columns in the coefficient matrix are investigated. This case study illuminates the issue of “symmetry” in the treatment of two sets of coordinates for identical point fields, a topic that had already been emphasized by Teunissen (1989, Festschrift to Torben Krarup, Geodetic Institute Bull no. 58, Copenhagen, Denmark, pp 335–342). The differences between the standard least-squares and the TLS approach are analyzed in terms of the estimated variance component and a first-order approximation of the dispersion matrix of the estimated parameters.     

点苍山-哀牢山变质杂岩带变沉积岩的变质演化

点苍山-哀牢山变质杂岩带位于青藏高原东南缘大理-元江-元阳-河口一带,出露规模达数百千米,是扬子板块和印支陆块之间的一条重要构造带.该变质杂岩带主要由各类正片麻岩、副片麻岩、大理岩所组成,夹有斜长角闪岩、石榴辉石岩和超镁铁质岩石的透镜体或团块.其中,变沉积岩如含夕线石和蓝晶石的片麻岩类岩石保存了多阶段的矿物组合及异常复杂的矿物相转变关系.详细的岩相学、成因矿物学以及矿物相转变关系分析表明,变沉积岩系经历了早期进变质阶段(M1)、峰期角闪-麻粒岩相变质阶段(M2)、峰后近等温减压(脱水熔融)阶段(M3)以及晚期退变质阶段(M4)的变质演化.其中,M1阶段的稳定矿物组合为石榴石+斜长石+白云母+石英+十字石±蓝晶石±黑云母±钾长石,M2阶段的稳定矿物组合为石榴石+黑云母+蓝晶石/夕线石+斜长石+石英、石榴石+黑云母+斜长石+石英±钾长石±夕线石,M3阶段的共生矿物组合为石榴石+黑云母+夕线石+斜长石+石英,M4阶段的矿物组合为黑云母+白云母+斜长石+石英±钾长石±石榴石等.通过传统GB-GASP温压计和二云母温度计的估算结果,配合P-T视剖面定量计算,确定早期进变质阶段(M1)的温压条件为T=560 ～ 590℃,P=5.5 ～6.3kb,峰期角闪-麻粒岩相阶段(M2)的温压条件为T=720～ 760℃、P=8.0～9.3kb,峰后近等温减压阶段(M3)的温度压力条件为T=640～760℃,P=5.0～7.3kb,晚期退变阶段(M4)的温压条件为T=521～648℃,P=4.0～5.0kb.上述研究结果表明,点苍山-哀牢山变沉积岩记录了典型碰撞造山带型式的顺时针P-T演化轨迹,表明点苍山-哀牢山变质杂岩带的形成与印度板块和欧亚板块之间的俯冲-碰撞存在密切的成因关系.     

坐标转换中大地高对平面坐标和高程的影响

验证大地高的不确定性对高程的影响和对平面坐标的影响,为具体工程实际应用提供参考依据.通过改变选定的重合点上的大地高,求得两套转换参数,并比较这两套转换参数求得的高斯平面坐标.通过不同数据验证,得出结论.     

Application of perfectly matched layers in the transient analysis of dam–reservoir systems

The transient analysis of dam–reservoir systems by employing perfectly matched layers has been investigated. In previous studies, boundary conditions of the PML region in the reservoir have been neglected. In this paper, they are incorporated completely in the formulation. Moreover, a technique is introduced to involve the effect of incident waves caused by vertical ground motions at the reservoir bottom in the analysis. Performing several numerical experiments indicates that applying boundary conditions of the PML domain and utilizing the proposed method for vertical excitation cases reduce the computational cost significantly and make the PML method a very efficient approach for the transient analysis of dam–reservoir systems.