In-plane–out-of-plane non-linear model of masonry infills in the seismic analysis of r.c.-framed buildings

The out-of-plane (OOP) behaviour of masonry infills (MIs), inserted in reinforced concrete (r.c.)–framed buildings, is recognized as one of the most important failure modes of this nonstructural element during an earthquake, which may be a consequence of simultaneous or prior in-plane (IP) damage. A five-element macro-model, with four diagonal OOP non-linear beams and one horizontal IP non-linear truss, with an equivalent mass of the infill panel divided between two central nodes, takes into account the IP and OOP failure modes occurring in the event of seismic loading. Pivot hysteretic models predict the non-linear IP and OOP force-displacement laws of the infill panel, based on geometrical rules defining loading and unloading branches. Firstly, a calibration of the proposed IP-OOP interaction model of MIs is carried out considering full-scale experimental results of traditional masonry typologies. Each specimen is initially subjected to in-plane quasi-static cyclic loading, until a maximum drift is reached, and then one-sided OOP cycles are imposed pushing in the horizontal direction and back to zero force. Then a numerical investigation considers masonry infills of an existing six-storey r.c.-framed building designed in compliance with a former Italian seismic code. To evaluate the interaction, the results of simultaneous IP and OOP cyclic tests on MIs at the top, intermediate, and lowest levels of the test structure are presented, assuming different displacement histories: (1) OOP loading faster than IP, at the sixth storey; (2) equal IP and OOP loading, at the third storey; (3) IP loading faster than OOP, at the first storey. Finally, attention is focused on the contribution of masonry infills to the IP and OOP energy dissipation of r.c.-framed structures.     

青岛地区坛张网生产情况的调查研究

本文对青岛地区坛张网生产情况进行深入广泛调查的基础上，结合国内外捕捞技术的研究新成果、新趋势，以及作者在渔船改造方面的研究，提出了青岛地区坛张网提高效率、保护资源的一些建议。     

Seismic response of three‐dimensional r/c multi‐storey frame building under uni‐ and bi‐directional input ground motion

This paper deals with seismic analysis of plan‐asymmetric r/c frame multi‐storey buildings. Non‐linear numerical analyses are carried out by using a lumped plasticity model for beams and a multi‐spring model for columns, the latter one introduced to account for axial force–biaxial bending moment interaction. A comparison between numerical analyses and experimental test results is reported in order to calibrate the numerical model, showing that the adopted model is very suitable. In order to study the effects of the earthquake orthogonal component, the seismic response of the modelled structure under uni‐directional excitation is compared to the one under bi‐directional excitation. Such comparison shows that the maximum base shear and the top displacement are not very sensitive to the presence of the orthogonal component, which, conversely, leads to large increase in the column plastic excursions. Copyright © 2007 John Wiley & Sons, Ltd.     

The Mel’nikov Subharmonic Function and the Non-existence of Analytic Integrals in Non-autonomous Systems

We consider a one-dimensional non-degenerate Hamiltonian system perturbed by a periodically time dependent non-Hamiltonian vector field and show that the non-vanishing of the Melnikov subharmonic function is strongly related to the non-existence of an analytic integral in the perturbed system.     

天山乌鲁木齐河流域冰川地貌与冰期研究的回顾与展望

乌鲁木齐河源于天山北列喀拉乌成山的北坡,区内保存着形态多样、较为清晰的第四纪冰川侵蚀与沉积地形.经过老中青数代人的考察研究,取得如下研究成果:1)查清了河源区冰川地形的分布与特征,运用冰川沉积学与地貌地层学原理对乌鲁木齐河出山口处的扇形地进行了冰川与非冰川成因的鉴别;2)基于地衣法、常规14 C与AMS14 C、TL、ESR、CRN(10Be)等多种定年方法的测年结果,并结合地貌地层学原理,建立了乌鲁木齐河流域小冰期、新冰期、末次冰期(MIS 2～4)、MIS 6与MIS12较完整的冰川演化序列,为我国第四纪冰川研究树立了一个典型范例.展望未来,乌鲁木齐河源区的冰川地貌演化模拟与古环境重建等需作进一步研究,喀拉乌成山南坡的冰川地形有待进行综合定年;若以乌鲁木齐河源流域冰期序列为参照,冰川发育与天山的构造抬升以及东、中与西段天山冰川发育是否具有一致性,天山地区是否保存有更老冰碛等科学问题尚待深入探讨.     

AGB星s-过程核合成相关问题的研究进展

综述了近年来AGB星核合成理论的研究情况,述及AGB星的结构与s-过程核合成有关的中子辐照量分布、人们比较关注的铅星与非铅星、后AGB星元素丰度分布及与AGB星核合成有关的s r星。     

Phylogenetic Diversity of Microorganisms from Chemocline of the Meromictic Soda Lake Doroninskoe(Zabaikalie,Russia)

正1 Introduction Many soda and salt lakes are characterized by the formation of the meromictic conditions under which a part of the water column is not involved in the annual process of mixing(Mac Intyre,Melack,1982).This creates an     

西藏果芒错蛇绿混杂岩中硅质岩的地球化学特征及其形成环境

果芒错蛇绿混杂岩位于狮泉河—永珠—嘉黎蛇绿混杂岩带中段,是该带中保存较好的一套蛇绿混杂岩,其形成环境是确定狮泉河—永珠—嘉黎蛇绿混杂岩带构造属性的重要依据。对果芒错蛇绿混杂岩中的硅质岩进行了地球化学分析,为判断蛇绿混杂岩的形成环境提供新的约束条件。硅质岩通常呈几十厘米夹层产于玄武岩中,含有大量晚三叠世—白垩纪放射虫化石。硅质岩SiO2含量为71.38%～77.67%,Al2O3含量为8.62%～11.51%,MnO/TiO2值为0.28～0.35,（Ce/Ce＊）SN值为0.92～0.94,（La/Ce）SN值为1.13～1.17,反映了陆源物质的影响,而V、Ni、Cu和V/Y值高于大陆边缘硅质岩,与洋中脊和大洋盆地硅质岩相似,说明果芒错硅质岩可能形成于受陆源物质影响且与大陆边缘有一定距离的环境中。结合变质橄榄岩、镁铁质岩墙和玄武岩的地球化学特征,初步认为果芒错蛇绿混杂岩的形成环境为靠近大陆边缘的弧后盆地。     

Comparative analysis of nonparametric change-point detectors commonly used in hydrology

ABSTRACT

Several commonly-used nonparametric change-point detection methods are analysed in terms of power, ability and accuracy of the estimated change-point location. The analysis is performed with synthetic data for different sample sizes, two types of change and different magnitudes of change. The methods studied are the Pettitt method, a method based on the Cramér von Mises (CvM) two-sample test statistic and a variant of the CUSUM method. The methods differ considerably in behaviour. For all methods the spread of estimated change-point location increases significantly for points near one of the ends of the sample. Series of annual maximum runoff for four stations on the Yangtze River in China are used to examine the performance of the methods on real data. It was found that the CvM-based test gave the best results, but all three methods suffer from bias and low detection rates for change points near the ends of the series.     

天山乌鲁木齐河源1号冰川1959-2009年物质平衡变化过程及特征研究

以天山乌鲁木齐河源1号冰川1958/1959—2008/2009年度物质平衡资料为基础,研究了冰川的物质平衡变化过程及特征.结果表明:51a来1号冰川物质平衡经历了9次负平衡波动和9次正平衡波动,负平衡年与正平衡年之比为35∶16,负平衡年平均物质平衡-450mm,正平衡年平均物质平衡130mm,多年平均物质平衡-267mm.1997—2008年,该冰川连续12a的物质平衡观测结果均为负平衡年,并且总体上处于数值很大的强负平衡,直至2008年出现了历史上最大的负平衡,物质平衡量为-999mm.1959—2009年,累积亏损达-13 646mm(约-2 402.6×104 m3),即冰川平均较之1959年减薄了15.2m,这种长时期连续物质亏损状态对1号冰川是一个严峻的考验.