Heterogeneity of water in garnets from UHP eclogites, eastern Dabieshan, China

Garnets in UHP eclogites from Bixiling in Dabieshan were investigated by Fourier transform infrared spectroscopy (FTIR). The results indicate that all garnets contain structural water that occurs as hydroxyl (OH⁻) and non-structural molecular water (H₂O) possibly in the form of sub-microscopic fluid inclusions. The structural hydroxyl contents range from 92 to 1735 ppm (H₂O wt.) and most are between 200 and 1000 ppm. Therefore, garnet in eclogite can recycle surface water into the mantle. Various water contents were observed among different samples of the same outcrop (∼150 m) and in different domains of the same sample (∼1 cm). This variability in structural H₂O contents suggests that the mobility of fluids during UHP metamorphism was very limited, and that both subduction and exhumation processes of UHP rocks occurred in a short time interval.     

鄱阳盆地构造—沉积特征及其演化史

鄱阳盆地是发育在江南—九岭和怀玉—官帽基底拆离造山带上的白垩-古近纪张扭性断陷盆地,明显受近南北走向的赣江走滑断裂系和前白垩系逆冲断裂系晚期反转的双重因素控制,呈“两坳夹一隆”的区域构造格局。受赣江、进贤—石门街走滑断裂夹持的南昌凹陷,呈近南北向凹凸相间展布格局。进贤—石门街走滑断裂以东地区,“南断北超”型断陷自南而北由北东走向渐转为北北东向展布,其源于晚印支-燕山期北东向逆冲断裂在晚期的反转作用,西缘和北部受赣江断裂系东枝走滑断裂影响明显而发生转向。鄱阳盆地经历了早白垩世晚期(冷水坞组沉积期)拉分盆地、晚白垩世早-中期(周家店组—南雄组沉积早期)走滑张扭断(坳)陷盆地、晚白垩世晚期(南雄组沉积中-晚期)走滑伸展盆地和古近纪坳陷盆地等演化阶段,东南部断陷区(江埠—二甲村凹陷)由于喜马拉雅期的隆升剥蚀而只残存周家店组早期坳陷和周家店组中期—南雄组中期断陷两个发育阶段的沉积。     

基于多时相Landsat数据的城市扩张及其驱动力分析

 以长沙市为例，在多时相Landsat遥感数据支持下，采用监督分类、非监督分类和归一化裸露指数(NDBI)等方法提取城市用地信息。通过对比多期城市用地的熵值变化，定量分析城市扩张的时空特性； 运用叠加、缓冲区分析等方法，分析城市扩张和中心城区的关系，绘制城市扩张速度玫瑰图。研究结果表明，长沙市建成区总面积不断扩展，其中，1973~1986年扩张主要表现在东南方向，1987~1993年为西部方向，1994~2001年南和东南方向成为快速扩张方向； 对长沙城市扩张驱动力进行分析，认为人口迅速增加是城市扩张的最主要驱动力。     

The Alpine evolution of the Southern Alps around the Giudicarie faults: A Late Cretaceous to Early Eocene transfer zone

Data supporting relevant Late Cretaceous–Early Eocene sinistral displacement along the Giudicarie fault zone and a minor Neogene dextral displacement along the Periadriatic lineament are discussed. The pre-Adamello structural belt is present only in the internal Lombardy zone, located W of the Adamello massif. This belt is unknown in the Dolomites and surrounding areas located to the E of the Giudicarie lineament. Upper Cretaceous–Early Eocene thick syntectonic Flysch deposits of Lombardy and Giudicarie are well preserved along the southern and eastern border of the pre-Adamello belt (S-vergent Alpine orogen). Towards the E, in the Dolomites and in the Carnic Alps and external Dinarides, only incomplete remnants of Flysch deposits, Aptian–Albian and Turonian–Maastrichtian in age, are present. They can be considered as equivalent to those of Lombardy and Giudicarie formerly in connection to each other along the N-Giudicarie corridor. To the S, the syntectonic Flysch deposits are laterally replaced by the calcareous red pelagites of the Scaglia Rossa and by the carbonate shelf deposits of the Friuli (to the E) and Bagnolo (to the S) carbonate platforms. The different location in the southern structural accretion of the eastern and western opposite blocks (the Dolomites versus the pre-Adamello belt) can be related to the Cretaceous–Eocene convergence. In this frame, the N-Giudicarie fault has been considered as part of a former transfer zone, which produced the sinistral lateral displacement of the Southern Alps front for an amount of some 50 km. During the Late Eocene to Early Oligocene the transfer zone was mostly sealed by the Paleogene Adamello batholith. Oligocene to Neogene compressional evolution inverted the N-Giudicarie fault into a backthrust of the Austroalpine units over the South-Alpine chain.     

Structural evolution of zeolite levyne under hydrostatic and non-hydrostatic pressure: geometric modelling

This is an exploratory study on the high-pressure (HP) structural evolution of a zeolitic framework (with LEV topology) on the basis of geometric modelling and previously published accurate unit-cell constants measured by means of single-crystal X-ray diffraction. The geometric simulations for 11 P values from 0 to 5 GPa gives more insight into the HP-behaviour of levyne, showing that the anomalous elastic behaviour of this zeolite observed under hydrostatic conditions at low P (P<1 GPa) is due to a double change in the compressional mechanism. Since the geometric simulation is not restricted to using the experimentally determined cell parameters, simulations of uniaxial compression along the [001] direction and of compression in the (001) plane have been performed, shedding more light on the compression mechanisms under non-hydrostatic regimes, which are difficult to access experimentally. The mechanisms associated with compressions along different axes provide insight into the hydrostatic compression mechanisms leading to the anomalous elastic behaviour.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

On the relative performance of spectrum superposition methods considering modal interaction effects

The contribution of modal interaction in the various available spectrum superposition methods is accounted via the modal cross-correlation coefficient, which has been defined in several different approximate ways. Further, in these methods, to define the final expressions directly in terms of the response spectrum amplitudes, the peak factors for all the modal responses are approximated to be equal to the peak factor for the total structural response. However, these assumptions have been found to be violated significantly in many cases and do not hold good in general. Therefore, some recent studies have attempted to improve upon these assumptions. In this paper, detailed investigations are made to study the relative performance of the various available methods considering the modal interaction effects. To find out which of the available methods, in general, gives the better results, the response of a five-storey asymmetric hypothetical building, characterized by significant interaction effects, has been computed from different methods for several widely differing input excitations and the results have been compared with the exact time-history solution.     

用主动调频质量阻尼器控制高层建筑的风致振动

本文提出了用于高层建筑风振动控制的主动调频质量阻尼器（ＡＴＭＤ）设计的一种简单方法。从ＴＭＤ的工作原理出发,在物理意义上显式定义主动控制力的构成,基于结构的ＳＤＯＦ模型和广义脉动风力的高斯白噪声假定,在频域的以最小化结构顶层位移方差为设计目标,对控制力增益进行参数优化,得出控制力增益的封闭解,文中提出了以维持ＴＭＤ行程恒定为目标进行参数选择的设计方案,一超高层建筑作为算例给出,数值分析表明,所设计     

部分输入未知条件下的结构系统识别研究

本文研究输入信息不完备条件下结构的参数识别问题,在对传统识别算法的特点进行分析的基础上提出了一种新的识别方法－全量补偿法。文中给出了算法理论证明和具体的数值算例。     

岩石古流变性质的构造研究进展

岩石古流变性质研究是大陆动力学研究的一个重要方面。岩石古流变性质研究的一个发展方向是通过比例模型,建立流变参数与构造变形几何参数之间的定量关系,再利用天然岩石构造变形几何参数的定量测定,反推在形成这些变形时所处物理化学条件下的岩石流变参数。对利用露头尺度地质构造的定量测量研究岩石古流变性质的方法与进展做了重点介绍。     

盾构隧道衬砌结构受力分析的梁—弹簧系统模型

盾构隧道衬砌结构由若干管片及其间的连接螺栓组成。在其断面受力的工程设计中,目前普遍采用梁-弹簧系统模型来模拟其受力性态。其中,梁可分成直梁和曲梁两类。本文在考虑弹簧刚度的轴向、切向和转动效应的同时,从卡氏（Castigliano）第二定理出发,给出了梁-弹簧模型的矩阵式,并论证了直梁-弹簧模型与曲梁-弹簧模型的一致性关系。在数值模拟计算过程中,还考虑了地层反作用力非线性情形和管片接头转动刚度正、负弯矩时的非对称性问题。