Weak compositional zonation in a silicic magmatic system: Incesu ignimbrite,Central Anatolian Volcanic Province (Kayseri – Turkey)

The Central Anatolian Volcanic Province (CAVP), one of four major volcanic provinces in Turkey, plays a significant role in the interpretation of the tectonic evolution of Central Anatolia. The CAVP developed within a complex collisional system involving the African, Arabian and Eurasian plates during the Miocene. The volcanism exhibits complicated variations in mineralogical, petrological and geochemical compositions resulting from post-collisional lithospheric dynamics. The Incesu ignimbrite has 5–20 m thick and covers an area of ～7800 km². It is composed of three stratigraphic levels. The lower level (LL) shows blackish brown and glassy welded structure. The middle level (ML) is a well-welded, reddish pink in color and has large amounts of fiamme. The upper level (UL) is grayish pink, weakly welded and has rock fragments of different compositions. The Incesu ignimbrite is composed of plagioclase (oligoclase, andesine) + pyroxene (augite, clinoenstatite) + opaque minerals and low amount of amphibole, biotite and quartz. Eutaxitic texture is dominant in ML and LL samples; these levels are more strongly and contain more flattened pumice fragments and volcanic glass shards than in the UL. A sharp color contrast defines the contact between LL and ML.Major, trace and rare earth element of the Incesu ignimbrite, characterized by their rhyolite, rhyodacite–dacite composition, medium–high K, calcalkaline and peraluminous nature, show fractional crystallization primarily controlled by plagioclase, clinopyroxene, magnetite, ilmenite and titanomagnetite. Sr and Nd isotopic ratios of Incesu ignimbrite display isotopic variations between the ignimbrite levels; they exhibit a limited range in ⁸⁷Sr/⁸⁶Sr (0.7043–0.7049) and ¹⁴³Nd/¹⁴⁴Nd (0.512716–0.512760). The Sr–Nd isotopic ratio of Incesu ignimbrite reveals an age of 3 Ma. The ignimbrite evolved through fractional crystallization and crystal contamination of the parent magma derived from Ocean Island Basalt (OIB) like magma. This suggestion is supported by the AFC modeling based on the trace elements and Sr isotope data.Variation of several major oxide concentrations (Fe₂O₃, TiO₂, CaO and K₂O), trace element concetrations (V, Sr, Cs and Rb) and trace element ratios (Ba/Rb, Sr/, K/Sr, K/Nb, Rb/Sr, Rb/Y and Rb/Nb) versus SiO₂ concentration show the magma chamber that generated the Incesu ignimbrite was compositionally zoned. All geochemical and Sr–Nd isotpic datas can be interepreted to be the result of a subduction related source.     

A Fine Structure of the Perseid Meteoroid Stream

A fine structure of the Perseid stream in the range of photographic magnitudes is studied using the method of indices. A new completed 2003 version of the IAU Meteor Data Center Catalogue of 4581 photographic orbits is used. The method of indices is used to acquire a basic data set for the Perseids. Subsequently, the method is applied on the chosen Perseids to study their structure. Sixty four percent of chosen Perseids taken into account are attached to one of the 17 determined filaments of orbits. The filaments are not distributed in the space accidentally, but they form a higher structure consisting of at least four well-defined and distinguished “branches”.     

车载三维数据采集系统的绝对标定及精度分析

针对GPS/INS/CCD相机集成的车载三维数据采集系统,给出了系统精确的直接定位方程,并将罗德里格矩阵用到系统的绝对标定中,推导了定位方程中所需的相机坐标系和惯导载体坐标系之间的平移与旋转参数的求解公式.然后,根据误差传播定律,推导了X、Y、Z三个方向上的坐标误差公式及点位误差公式.实验结果表明,本标定方法意义明确,计算过程简单,具有较高的标定精度,对实际应用具有重要的价值.     

High temperature extremes in the Czech Republic 1961–2010 and their synoptic variants

Our research focuses on the analysis of extreme high maximum air temperature events (EXHTEs) in the Czech Republic in the period 1961–2010, their climatological characteristics, and on the identification of synoptic-scale circulation conditions conductive to them. EXHTEs are detected using the Weather Extremity Index (WEI) combining return periods of daily maximum air temperature, duration of events, and the extent of the affected area. We selected 37 EXHTEs as non-overlapping periods with the highest WEI. Some long EXHTEs were divided into several shorter synoptically homogeneous episodes. Using the two-level divisive clustering of 700 hPa air temperature and wind field anomalies, we obtained four main variants of synoptic-scale circulation conditions. The most frequent variant associated with extreme episodes is characterized by a westerly flow connected with a high pressure ridge extending northeastward from North Africa over Central Europe or with an anticyclone centered over the Central Mediterranean. The most extreme episodes occurred during the variant characterized by an easterly flow between a high pressure area to the northeast and a low pressure area to the southeast.     

基于正交实验的卧式浪流发电轮机叶片分析

基于现有波浪能和潮流能发电装置研究现状,为达到波浪和潮流同时利用的目的,设计了一种以卧式轮机形式同时吸收水平波浪螺旋力和潮流能动力的新型浪流发电装置。通过正交试验设计得到三指标最佳叶片参数组合后,进行FLUENT流场分析,从流体角度出发,在其扭矩、推力以及轮机功率三方面对比分析,阐明了叶片参数对于轮机流场的作用趋势,并以此趋势为参考择出最佳模型。后期水槽实验有效验证了该卧式浪流轮机的浪流结合吸收的可行性。     

Histological alterations observed in Idotea balthica basteri audouin 1827 (Crustacea,Isopoda) exposed to the chronic effect of non-ionic detergents

Following extended exposure to eight non-ionic compounds, the crustacean isopod Idotea balthica basteri was studied by light microscopy and histoautoradiography. Cellular modifications were found in the nervous system, the gill pleopods, the digestive system, the gonads and the moulting gland. It is suggested that these modifications may eventually cause a variation in function and may even lead to the extinction of the species.     

Groundwater nitrate pollution in an alluvium aquifer, Eskişehir urban area and its vicinity, Turkey

 A large amount of the water requirement (municipal, industrial, etc.) of Eskişehir city, Turkey, is supplied from groundwater via wells in the urban area. The groundwater in the Eskişehir Plain alluvium has been polluted by municipal and industrial wastewater, and agricultural activities. The nitrate concentrations at nine sampling points on Porsuk River, the main water course in the plain, ranged from 1.5 to 63.3 mg/l during the period from July 1986 to August 1988. In the same period, the nitrate concentrations measured in water from 51 wells ranged between 2.2–257.0 mg/l. The nitrate content of the groundwater samples was 34.2% above 45 mg/l, the upper limit for nitrate in drinking water standards. High nitrate levels were observed in water from wells in the central and eastern parts of the urban area. The nitrate content of the well water is subject to seasonal fluctuation. In general, low nitrate concentrations were observed in wet seasons, and high ones in dry seasons. Received: 16 April 1996 · Accepted: 2 October 1996     

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in sediments from Hong Kong

Concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in 14 sediment samples collected from four sites in the Mai Po Marshes Nature Reserve (within a RAMSAR Site) and from another six sites in Victoria Harbour and along the Hong Kong coastline. Elevated levels of PCDDs, and particularly OCDD, were detectable in all samples collected from the Mai Po Marshes and five of the six sites. In contrast to PCDDs, PCDFs were mainly found in sediment samples collected from industrial areas (Kwun Tong and To Kwa Wan) in Victoria Harbour. PCDD/F levels and congener profiles in the samples from the Mai Po Marshes Nature Reserve in particular show strong similarities to those reported in studies which have attributed similar elevated PCDD concentrations to nonanthropogenic PCDD sources.     

Entwurf Eines Zweckmässigen Koordinatensystems auf der Approximativen Geoid—Fläche zur Bestimmung Ihres Verlaufes

Было быведено уравнение поверхости и отдельных вокторов ее сопровождающефо трсх-гранника, с параметрами, представляющими собой дуги основных парметрических кривых. Параметрическими кривыми здесь криволинейные линии поверхности (2), (3). Дальше был намечен вывод уравнений трансформирования аналогичных параметров для случая общей ортогональной системы с общим началом, в выше приведенную систему (4). Система пря-моугольных криволинейных координат, соответствующих направлениям экстремальных искажений длин в случае общего отображения первоначальной поверхности на другой, была применена к определению трансформационных формул (отображения) для дуг криволинейных линий (6). Было выведено уравнение поверхности отображения с параметрами, представляю-щими собой дути криволинейных линий на первоначальной плоскости (7). Этот способ был использован также в случае единичных векторов сопровождающего трехгранника в отобра-жении (8). В результате зтого получены для обеих поверхностей одинаковые параметры, чем окжется возможным, например, сравнение нормалей поверхности отображения—считаемой приближением геоида—с системой нормалей, полученных по целесообразно редуцирован-ным астрономическим широте и долготе, или же сравнение нормалей и координат обеих поверхностей. Поверхностью относимости считается первоначальная поверхность. Так как результирующие уравнения содержат—кроме констант, определяющих отображение не зависимо от формы поверхности—также и инвариантные выражения, имеющие геометри-ческое значение, то они применимы к определению формы поверхности отображения.