Highly ordered monoclinic K-feldspars from Haut Boréon anatexites,Argentera Massif,Maritime Alps

Summary In microperthitic alkali feldspars from the Haut Boréon anatexites in the Argentera Massif, Maritime Alps, the dominant K-rich phases are devoid of grid twinning but usually show weak uneven extinction. They consist of monoclinic forms characterized by (a) highly ordered Si,Al distributions in theT-sites, (b) weak but systematic residual strain due to coherency with the exsolved Na-rich phase, and (c) not very pure compositions ranging from 0.85 to 0.88 mole fraction KAlSi₃O₈. Weak triclinic peaks in X-ray powder patterns and the evidence of incipient formation of M-twinning and the diagonal association in single-crystal X-ray photographs indicate that the dominant monoclinic K-rich phases have undergone a partial transformation into triclinic material. The microperthites investigated appear to be the expression of a relatively rapid thermal history which started and terminated at temperatures higher than those experienced by the microperthites from the Mt. Pélago anatexites, which are exposed to the West of the Haut Boréon anatexites.

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Monokline K-Feldspäte mit hohem Ordnungsgrad aus Anatexiten des Haut Boréon, Argentera Massiv Seealpen

Zusammenfassung In den mikroperthitischen Alkalifeldspäten der Anatexite des Haut Boréon im Argentera Massiv (Seealpen) zeigen die vorherrschenden monoklinen Phasen keine Zwillingsgitterung, aber gewöhnlich schwach unregelmäßige Auslöschung. Sie bestehen aus monoklinem Kali-feldspat, der 1, durch eine weitgehend geordnete Si,Al-Verteilung auf denT-Positionen, 2. durch schwache aber systematische Spannungen, welche durch die Kohärenz mit der entmischten Na-reichen Phase verursacht sind, und 3, durch eine nicht sehr scharfe Zusammensetzung, die von 0,85 bis 0,88 Molenbruch KAlSi₃O₈ schwankt, charakterisiert ist. Schwache trikline Maxima in den Röntgen-Pulverdiagrammen sowie der Hinweis auf beginnende M-Verzwilligung und diagonale Assoziation in Röntgen-Einkristallaufnahmen weisen darauf hin, daß die vorherrschenden monoklinen Phasen partiell in triklines Material umgewandelt wurden. Die untersuchten Mikroperthite scheinen eine relativ rasche thermische Geschichte zu widerspiegeln, die bei höheren Temperaturen begann und endete als jene, welche die westlich des Haut Boréon aufgeschlossenen Anatexite des Mt. Pélago erlitten.

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With 6 Figures     

1730年夏季黄淮地区暴雨极端事件研究

1730年（清雍正八年）7—8月,我国黄淮地区连续暴雨17 d,引起黄河、大运河和淮河暴涨、决堤的大范围洪涝灾害。这是小冰期中相对温暖时段气候背景下的极端气候事件。本文依据历史文献记载复原了1730年夏季暴雨时段的天气实况,绘制了暴雨区域图显示强降雨中心移动动态和水灾地域分布图,概述当年气候特点,指出暴雨事件与台风活动的关联。1730年是太阳活动周极小年的前3年、有重大火山活动,是极强的厄尔尼诺事件后的第2年。这些天气特点和背景条件与现代罕见的1975年河南“75?8暴雨”相似。     

Evolution of sand waves in the Messina Strait, Italy

In the present paper the morphodynamics of sand waves in the Messina Strait, Italy, is analysed by comparing data gathered during two different surveys carried out in 1991 and 2001, respectively. In particular, a morphometric analysis on the most recent data and a qualitative analysis of the differences between bottom bedform patterns, are carried out. At locations characterised by greater depths, only minor changes to the planimetric configuration of the field, i.e. crest orientation (which is seen to be orthogonal to the direction of net gross sand transport) and wave length are observed, while differences in wave length and crest direction are more evident in more shallow areas. On the other hand, wave height has significantly increased in the whole field. A possible explanation of such a change, based on the previsions of a theory which relates sand-wave growth and migration to the main components of the tidal ellipse, is provided.Responsible Editor: Jens Kappenberg     

Wavelet Spectrum Analysis Of Eit/Soho Images

The extreme ultraviolet imaging telescope (EIT) of SOHO offers a unique record of the solar atmosphere for its sampling in temperature, field of view, resolution, duration, and cadence. To investigate globally and locally its topology and evolution during the solar cycle, we consider a multi-scale approach, and more precisely we use the wavelet spectrum. We present three results among the applications of such a procedure. First, we estimate the typical dimension of the supergranules as seen in the 30.4 nm passband, and we show that the evolution of the characteristic network scale is almost in phase with the solar cycle. Second, we build pertinent time series that give the evolution of the signal energy present in the corona at different scales. We propose a method that detects eruptions and post-flaring activity in EUV image sequences. Third, we introduce a new way to extract active regions in EIT images, with perspectives in, e.g., long-term irradiance analysis.     

A review of research on seismic behaviour of irregular building structures since 2002

The paper presents an overview of the progress in research regarding seismic response of plan and vertically irregular building structures. Three areas of research are surveyed. The first is the study of the effects of plan-irregularity by means of single-storey and multi-storey building models. The second area encompasses passive control as a strategy to mitigate torsional effects, by means of base isolation and other types of devices. Lastly, the third area concerns vertically irregular structures and setback buildings. Although fewer papers have been published in this last area with respect to the former ones, this state-of-the-art reports extensively on research efforts and progress into the seismic behaviour of irregular buildings in elevation to show the growing interest among specialists in the field.     

中国西北地区石羊河流域农业生态系统能值评价

通过能值方法分析了石羊河流域农业生态系统的资源环境基础和经济特征。结果表明,石羊河流域中下游凉州区和民勤绿洲的能值总投入呈降低趋势,能值投资率都偏高,生产成本较大;能值产出率低,对购买能值的利用效率不高;但能值自给率有所提高;环境载荷率高,农业生态环境所受压力较大,系统可持续发展指标表明两个绿洲经济系统极为不发达,属于消费型经济系统,并且人均可用能值和能值密度都呈降低趋势。     

基于虚拟监控技术的机器人系统

介绍了一种虚拟现实技术(VR)与智能机器人监控技术协同作业的机器人系统,该系统使用虚拟现实技术建造具有良好交互性的人机界面,并且结合智能机器人监控技术,实现了虚拟监控操作。通过机器人系统,将虚拟操作结果作为一个整体对象投射到工作现场,完成了实际作业,并以水下机器人检查钻井平台水下部分的焊缝工作为背景,说明了本系统各种功能的实现过程。