高温高压实验及原位测量技术

文中简述了高温高压实验技术及其发展现状,主要涉及高温高压实验装置及高温高压原位实验测量技术两方面内容。重点介绍了:(1)金刚石压腔、大体积压力机、高压釜等静态高压实验技术和动高压实验技术及其特征;(2)拉曼、红外、X-射线衍射及同步辐射等高温高压原位谱学研究;(3)超声波、布利渊散射、核共振非弹性X-射线散射等高压物质弹性波速原位测量技术研究现状及其进展;(4)金刚石压腔、大压力机中高温高压电导率的原位测量技术研究现状及其进展。     

导线环垂直激发场高精度数值模拟

导线环垂直激发场是导线环在地下产生的激发场中垂直于地磁场的分量,在地面核磁共振找水方法中,垂直激发场在地下的分布直接决定地面核磁共振响应,探讨影响垂直激发场地下分布的诸因素进而研究这些因素对地面核磁共振响应的作用,对核磁共振找水正确野外施工具有一定的指导意义,有助于采集更高质量的野外数据.利用经典Chave算法对含有贝塞尔函数的强振荡积分核进行了数值积分试验,将其计算结果和对应的解析解进行了对比,试验结果显示该算法用于强震荡函数无穷积分的计算具有良好的收敛性、较高的精度和较快的计算速度,采用Chave算法对含有贝塞尔函数的强振荡函数进行积分是可行的.在此基础上,进一步计算并数值模拟了导线环垂直激发场及其相位,分别从地磁倾角、磁偏角、地下介质导电性、深度等方面探讨了影响垂直激发场及其相位分布的主要因素.     

A vortex-tube model of eddies in the inertial range

Abstract

A vortex-tube geometry of the cascade of energy to small-scale eddies, in the inertial range of fully-developed turbulence, is proposed. The model is a special case of the beta model of Frisch, Sulem and Nelkin (1978). We require that the cascade conserve the principal invariants of inviscid, incompressible flow, namely volume, topological knottedness, circulation, and, at discrete times marking the termination of steps in the cascade, energy. The process terminates in a finite time, as in any beta model, leaving behind a self-similar network of “inactive” tubes. We associate a self-similar scaling dimension D with the structure, equal to the Hausdorff dimension of the set of “active” tubes at the termination of the cascade. Because circulation Λ plays a key role in the analysis of the cascade, we refer to these vortex-tube geometries as “gamma models”. The viewpoint throughout is entirely deterministic.

We describe two examples of gamma models. In the ring geometry, an eddy is a vortex ring, and the cascade produces “rings upon rings”, so we allow cutting and fusing of tubes while conserving total helicity. In the preferred helical model, no cutting is needed, and the cascade produces an infinite progression of braided “coils upon coils”. We suggest that latter geometry as a candidate for the topology of a singularity of the inviscid limit of a Navier-Stokes flow, when modeled by discrete vortex tubes.

A crucial ingredient of a gamma model, not explicitly present in a beta model, is the possibility of “splitting” a vortex tube into sub-tubes carrying smaller circulation. We suggest a dynamical basis for this process, as an instability of tubes whose cores violate the Rayleigh criterion.

The parameters describing a gamma model are not uniquely determined by our study, but there is a “simplest” helical gamma model, involving minimal splitting and distortion of tubes. The dimension D of the structure is 13/5, with a scale factor Λ = 2^?5/4. This value of D agrees with that suggested by Hentschel and Procaccia (1982), by analogy with established results for certain branched polymers.     

Reconstruction of a flash flood with large wood transport and its influence on hazard patterns in an ungauged mountain basin

The reconstruction of past flash floods in ungauged basins leads to a high level of uncertainty, which increases if other processes are involved such as the transport of large wood material. An important flash flood occurred in 1997 in Venero Claro (Central Spain), causing significant economic losses. The wood material clogged bridge sections, raising the water level upstream. The aim of this study was to reconstruct this event, analysing the influence of woody debris transport on the flood hazard pattern. Because the reach in question was affected by backwater effects due to bridge clogging, using only high water mark or palaeostage indicators may overestimate discharges, and so other methods are required to estimate peak flows. Therefore, the peak discharge was estimated (123 ± 18 m³ s^–1) using indirect methods, but one‐dimensional hydraulic simulation was also used to validate these indirect estimates through an iterative process (127 ± 33 m³ s^–1) and reconstruct the bridge obstruction to obtain the blockage ratio during the 1997 event (~48%) and the bridge clogging curves. Rainfall–Runoff modelling with stochastic simulation of different rainfall field configurations also helped to confirm that a peak discharge greater than 150 m³ s^–1 is very unlikely to occur and that the estimated discharge range is consistent with the estimated rainfall amount (233 ± 27 mm). It was observed that the backwater effect due to the obstruction (water level ~7 m) made the 1997 flood (~35‐year return period) equivalent to the 50‐year flood. This allowed the equivalent return period to be defined as the recurrence interval of an event of specified magnitude, which, where large woody debris is present, is equivalent in water depth and extent of flooded area to a more extreme event of greater magnitude. These results highlight the need to include obstruction phenomena in flood hazard analysis. Copyright © 2012 John Wiley & Sons, Ltd.     

Dynamic model of mesoscale eddies. Eddy parameterization for coarse resolution ocean circulation models

In the framework of the eddy dynamic model developed in two previous papers (Dubovikov, M.S., Dynamical model of mesoscale eddies, Geophys. Astophys. Fluid Dyn., 2003, 97, 311–358; Canuto, V.M. and Dubovikov, M.S., Modeling mesoscale eddies, Ocean Modelling, 2004, 8, 1–30 referred as I–II), we compute the contribution of unresolved mesoscale eddies to the large-scale dynamic equations of the ocean. In isopycnal coordinates, in addition to the bolus velocity discussed in I–II, the mesoscale contribution to the large scale momentum equation is derived. Its form is quite different from the traditional down-gradient parameterization. The model solutions in isopycnal coordinates are transformed to level coordinates to parameterize the eddy contributions to the corresponding large scale density and momentum equations. In the former, the contributions due to the eddy induced velocity and to the residual density flux across mean isopycnals (so called Σ-term) are derived, both contributions being shown to be of the same order. As for the large scale momentum equation, as well as in isopycnal coordinates, the eddy contribution has a form which is quite different from the down-gradient expression.     

基于大比例尺数字高程模型DEM制作方法的经验和体会

大比例尺DEM更能够清晰详细地表述地面高程信息,它在测绘、水文、气象、地貌、地质、土壤、工程建设、通讯、气象、军事等国民经济和国防建设以及人文和自然科学领域有着广泛的应用。针对大比例尺DEM的制作精度要求比较高、制作成本高的特点,本文提供大比例尺数字高程模型DEM制作方法的一些经验和体会。     

新型堵漏工具——拦截式堵漏工具的研究

针对大溶洞或裂缝漏失,利用研究的拦截式堵漏工具将堵漏浆拦截在一定位置,对大裂缝漏失地层、溶洞性漏失地层进行有效封堵,从而解决该类恶性漏失问题,提高钻探施工质量和钻探效率,降低钻探成本,为钻探工程特种漏失堵漏提供新途径。     

AQK嵌岩扩底钻头的结构特点

论述了AQK大直径嵌岩扩底钻头的结构设计特点,阐述了新型扩底钻头的适应性和可靠性,对扩底钻头制造及钻扩施工过程中的关键问题提出了几点要求。     

Stratigraphic records of the dynamic uplift of the Emeishan large igneous province

Abstract

Fluid dynamical and numerical modelling predicts a large-scale regional domal uplift prior to basalt eruptions in large igneous provinces, which can be readily measured when a plume head rises below a shallow marine sedimentary basin. Research on the sedimentology, biostratigraphy, and isotopic chronology of the Emeishan large igneous province demonstrates that the sedimentary environment in the Maokou stage is not uniform carbonate platform facies, but rather sedimentary facies with a north–south linear alignment and west–east different distribution controlled by the syn-depositional normal faulting of the Changhai and Xiaojiang faults, which are the result of underwater dynamic uplift induced by deep mantle activity. The dynamic uplift started in the Maokou stage. Thus, thinning of the Maokou limestone was the product of the difference in the initial depositional thickness caused by the underwater uplift and post-depositional surface uplift and erosion, but post-depositional uplift was much less than kilometre scale. Sedimentary facies differentiation and tectonic–sedimentary evolution in the Maokou stage provide a constraint for the time of the initial eruption and eruption environment before and during the Emeishan basalt eruption. Small-scale magmatic activity might have already begun in the middle of the Maokou stage, whereas submarine and terrestrial sedimentary environments coexisted before and during Emeishan basalt eruption.     

内蒙古磨石山沉积变质型锐钛矿矿床：一个大型新类型钛矿床的发现、勘查和研究

前人把内蒙古正蓝旗磨石山南部的羊蹄子山矿床确定为铁矿床,通过我们近几年的研究和勘查,发现了北部的磨石山新钛矿带,认为这不是一个铁矿,而是一个以锐钛矿为主的大型沉积变质型钛矿床,是钛矿床的一个新类型。矿体产于中元古代(1751Ma)片岩、变质石英(粉)砂岩和斜长角闪岩中,呈似层状、透镜状产出。富矿石具有细纹状构造,表现为以石英和锐钛矿为主的条纹互层。矿石矿物主要为锐钛矿,次有金红石和钛铁矿(赤铁矿),脉石矿物以石英为主,含一定量直闪石和黑云母(石榴子石)。锐钛矿、金红石和钛铁矿的粒度很细,为0.01～0.1mm。富矿含TiO23.14%～15.46%,平均6.91%,而贫矿的TiO2含量为1.2%～2.97%,平均1.76%。矿石含较高的Fe和V。锐钛矿和金红石的微量元素Nb和Cr的含量很低,说明矿物的源区来自变质基性岩。围岩斜长角闪岩恢复其原岩,大致相当于玄武岩、苦杆玄武岩等。岩石化学揭示其生成构造条件,为岛弧或岛弧和洋脊的过渡带。硅同位素组成研究结果,不同锐钛矿矿石、石英岩和片岩等的δ30Si值为0.1‰～-0.9‰,与海底热液喷气沉积矿床的数据相似。所有上述矿床的地质和地球化学特征表明,锐钛矿矿石和斜长角闪岩都是海底基性火山活动的产物,矿石具有化学沉积特征,后来遭到中(偏低)级区域变质作用,金红石主要形成于区域变质作用。矿床在燕山晚期(118Ma),由于花岗岩的侵位,又局部受到热液改造。