Saalian to Weichselian stratigraphy and sedimentation along the Lågjæren – Høgjæren escarpment,southwest Norway

Quaternary sediments along a profile crossing the southern part of the Jæren escarpment, southwestern Norway, have been investigated with regard to their glacial history and sea-level variations. Deposits from at least three glaciations and two ice-free periods between Oxygen Isotope Stage 6 and the Late Weichselian have been identified. Subglacial till directly overlain by a glaciomarine regressional succession indicates a deglaciation, and amino acid ratios in Elphidium excavatum between 0.083 and 0.118 date this event to Oxygen Isotope Stage 6. Sea-level dropped from 130 to below 110 m a.s.l. Subsequently, a short-lived ice advance deposited a marginal moraine and a sandur locally on the escarpment. Stratigraphical position and luminescence dates around 148 ka BP suggest deposition during the final stage 6 deglaciation. A Late Weichselian till covers most of the surface of Jæren. In addition to a well documented westerly ice flow, glaciotectonic indications of ice flow towards the north have been found. Ice flow directions and a hiatus between Oxygen Isotope Stage 6 and the Weichselian indicate enhanced erosion along the escarpment and the influence of a Norwegian Channel ice-stream. Copyright © 1999 John Wiley & Sons, Ltd.     

Combined Effects of Molecular Size and Electroendosmotic Flow on the Capillary Electrophoretic Behaviour of Humic Substances

The electroendosmotic flow (EOF), generated by the migration of solvated ions near the charged capillary surface, is an important factor in determining the capillary electrophoretic behaviour of humic substances (HS). We investigated the electrophoretic mobilities of HS fractions of reduced molecular-weight polydispersity extracted from peat and from a spodosol either in the presence or after suppression of the EOF. When the EOF was not suppressed, HS migrated to the cathode in spite of their negative charge. Fractionation of HS according to molecular size was achieved in polyacrylamide-coated capillaries filled with 0.05 M tris-phosphate buffer. In uncoated capillaries filled with the same buffer, all fractions had very close mobilities. Addition of polyethylene glycol MW 4000 at concentrations above its entanglement threshold caused the migration times of larger molecules to increase more than those of smaller molecules. The separation was a linear function of molecular size up to 75000 g mol^–1 for peat HS and to 50000 g mol^–1 for HS extracted from the spodosol.     

Spectroscopic Characterization of Fulvic Acid Fractions of a Contaminated Groundwater

Two fulvic acid (FA) samples taken from a former gas production facility in the Southwest of Germany were characterized using advanced fluorescence techniques. Steady-state fluorescence (fluorescence excitation, synchronous fluorescence) as well as time-resolved fluorescence were applied. Distinct differences between the sample B22 FA taken within the contamination plume and the sample B53 FA taken downstream were found. Comparison with a model compound for metabolites and humic substances revealed that due to the downstream passage the characteristics of the dissolved organic matter became more humic-like. The assignment of single classes of compounds in the sample B22 FA is discussed in terms of their synchronous fluorescence spectra and fluorescence decay time distribution.     

基于钢筋锚杆接地电阻评价锚固质量研究

本文采用接地电阻作为评价钢筋锚杆锚固质量的标准.当锚杆、砂浆、围岩三者接触不密实、不均匀时必然会引起锚杆接地电阻的变化.因此将锚杆接地电阻的理论计算值作为评价锚固状态的参照,利用实际测量值与之作比较,从而对锚杆质量进行分级评价.在利用此方法评价锚杆质量时,准确测量锚杆的接地电阻则尤为重要,采用6极法可以消弱由于大地的各相异性对于接地电阻测量带来的误差,提高测量精度.     

利用6S模拟大气效应

遥感成像过程中由于大气辐射传输过程会导致遥感影像偏离真实地物影像。介绍了利用6S软件计算结果对这一情况进行模拟的详细步骤,是一种新的影像仿真方法和途径。     

Cr 135 revisited

In this paper we combine information on photometry, radial velocities and proper motions to study the nature of the suspected open cluster Cr 135. For the first time we introduce proper motions of a large number of stars in the region of Cr 135 into the discussion. The proper motions taken from the PPM catalogue favour the hypothesis that Cr 135 is a real open cluster with at least 12 members at a distance of 300 pc having a space motion U, V, W of (−11, −13, −15) km s⁻¹. But still more accurate observations are needed to separate it from the field stars without any doubt.     

Approaches to census mapping: Chinese solution in 2010 rounded census

China still use sketch maps as control devices that guarantees consistency and accuracy of population counting in previous census.Although the rapid advancement of geospatial technologies provides many possible solutions of digital census mapping,existing researches do not answer which solution is suitable to China.Subject to many constraints originated from characteristics of China,a practical solution of census mapping based on remote sensing imagery and auxiliary geographic information was proposed and proved to be feasible through evaluation analysis and a three-stage pilot study.Imagery with 2.5 meters and higher resolution,innovative workflow of census areas delineation,easy-to-use census mapping software packages and training organization all together provide the all-around supports for the 2010 rounded census (the 6th census) mapping activities.A digital census geographic framework detailed at the level of enumeration area was established in the 2010 rounded census which fills in the gaps in the field of modern geospatial census in China.The spatially referenced digital census database,especially the detailed census units,is of great value in successive census,sampling survey and many other census-related fields.Future work including quality evaluation of census areas,census mapping solution in the Tibet Autonomous Region are also discussed.     

地下水中稳定铬同位素的生物地球化学作用

铬是地下水中常见的一种变价重金属污染物,在自然界中广泛分布且应用广泛。将Cr(Ⅵ)还原为Cr(Ⅲ)是地下水铬污染防治中的主要策略。在Cr(Ⅵ)的非生物还原过程中存在铬同位素分馏现象,通过地下水中铬同位素组成的变化情况可以定量地指示Cr(Ⅵ)的还原程度和速率。这被认为是一个重要发现,在地下水铬污染防治中有着广阔的应用前景。文中对铬与铬的来源、地下水中铬同位素的测定方法、铬同位素的生物地球化学作用、铬同位素在地下水污染防治中的应用等进行了系统综述。研究认为：微生物广泛参与地下水中铬的氧化与还原作用,并有可能产生显著的铬同位素分馏。地下水中被还原的Cr(Ⅵ)在微生物作用下有可能被活化,用非生物还原条件下的铬同位素分馏规律指示地下水中Cr(Ⅵ)还原程度可能会产生较大的误差。开展地下水中铬同位素的生物地球化学作用研究,特别是生物氧化Cr(Ⅲ)过程中的铬同位素分馏规律研究,对于更全面地认识铬同位素的指示作用具有重要意义。     

RCP4.5情景下淮河流域气候变化的高分辨率模拟

利用CCLM高分辨率区域气候模式RCP4.5情景预估数据与淮河流域1960-2005年日尺度气象观测资料,对比分析模式在试验期（1960-2005年）和预估期（2006-2040年）的模拟能力。结果表明：①试验期模式数据能较准确地模拟流域逐月平均温度时间变化特征,相关系数达0.99（通过95%置信度检验）;日均温空间分布特征相关系数达0.72;但在南部高海拔地区（安徽省霍山县和金寨县）精度不高;极端最高（低）气温的空间相关性达0.77（0.88）。②模式在试验期模拟的逐月平均降水量总体趋势与实测值变化一致,相关系数达0.63（通过95%置信度检验）;对干旱的模拟与观测数据存在一定误差,但整体趋势与其一致;年均降水量和极端强降水空间分布相关系数分别达0.90和0.93,模拟效果较好;整体上,模式对温度的模拟效果要好于降水模拟。③RCP4.5情景下,空间尺度上淮河流域未来温度和降水与观测期相比变幅小,时间尺度上年均降水量无显著变化,平均气温年际变化率约0.21℃/10a,极端高温持续增长,低温持续下降。