Mosaic and gradient SiGe single crystals for gamma ray Laue lenses

Both Ge_1−x Si _x mosaic crystals and Si_1−x Ge _x crystals with gradient of composition could be grown using the modified Czochralski technique to produce the diffracting elements for the MAX gamma ray telescope. Although many elements cut from the mosaic crystal and used before for CLAIRE gamma ray telescope had an efficiency up to 20%, the overall efficiency of the lens was about 8.1 ± 0.7 %, which is more than twice lower than the theoretically predicted efficiency. Some causes of this behaviour are discussed. In addition to mosaic crystals, the growth of Si_1−x Ge _x crystals with a gradient of composition and their properties are analysed. Such composition-gradient crystals could be a promising way to improve the diffraction efficiency of Laue lens for MAX.     

新发现7个X选 BL Lac天体和1个类星体(英文)

利用ROSAT－VLA方法筛选，从ROSATX射线源中选出了19个新BLLac天体和类星体的候选体．在1994年至1996年1月期间，利用北京天文台2．16m望远镜对其中16个进行光谱证认，发现了7个新的X选BLLac天体及一个类星体，类星体的红移值为：z＝0.331±0．0015．     

Public Participation in Rural Environmental Governance around the Water Source of Xiqin Water Works in Fujian

Public participation is an important way to improve the overall effect and social recognition of rural environmental governance in water source areas. Public participation makes environmental governance measures more targeted and effective, contributes to protecting the basic environmental rights of the public, and makes it easier to meet the livelihood needs of rural people. Public participation in rural environmental governance in water source areas is characterized by complex behavior and is dependent on public willingness to participate. Amongst other factors, it is subject to the combined influences of both internal (psychological cognition) and external (environmental regulation) conditions. This paper builds a theoretical framework for understanding public participation behavior in rural environmental governance, and uses it to analyze a case in the rural area surrounding the Xiqin Water Works in Fujian Province. In the case study, the public shows high willingness to participate, but low actual rates of participation. At the same time, the willingness of villagers to pay for the control of pollution from livestock and poultry breeding varies greatly from village to village, and there are also noticeable individual differences in public participation in the use of public collection points for rural household waste. We found that gender, understandings of environmental protection and perception of environmental regulation, play a key role in influencing the willingness of farmers to pay for the control of pollution from livestock and poultry breeding. Individual awareness of environmental protection, environmental protection facility conditions, and environmental service quality had a significant influence on public participation in the use of public collection points for rural household waste.     

Some geological-morphological features of the formation of gold-bearing placers in the Amur region

The intensity of placer formation is controlled by many factors, mainly by the erosion level of orebearing structures. Their deep erosion and long-term denudation resulted in the formation of numerous, often large placers with fine gold, which lost their relation with bedrocks and were derived mainly by rewashing of loose deposits from the depressions adjacent to the ore-bearing orogens. These placers are developed in many gold-bearing areas: Dambuki, Sutara, Erik, and others. Rich placers with coarse gold of high fineness were formed via erosion of gold mineralization that was previously metamorphosed by post-ore granitoids (Niman and Kerbi regions, Central Sikhote Alin).     

Isotopes in the Hueco Bolson aquifer, Texas (USA) and Chihuahua (Mexico): local and general implications for recharge sources in alluvial basins

Stable isotope data for the Hueco Bolson aquifer (Texas, USA and Chihuahua, Mexico) distinguish four water types. Two types relate to recharge from the Rio Grande: pre-dam (pre-1916) river water with oxygen-18 and deuterium (δ¹⁸O, δD, ‰) from (?11.9, ?90) to (?10.1, ?82), contrasts with present-day river water (?8.5, ?74) to (?5.3, ?56). Pre-dam water is found beneath the Rio Grande floodplain and Ciudad Juárez, and is mixed with post-dam river water beneath the floodplain. Two other types relate to recharge of local precipitation; evidence of temporal change of precipitation isotopes is present in both types. Recharge from the Franklin and Organ Mountains plots between (?10.9, ?76) and (?8.5, ?60) on the global meteoric water line (GMWL), and is found along the western side of the Hueco Bolson, north of the Rio Grande. Recharge from the Diablo Plateau plots on an evaporation trend originating on the GMWL near (?8.5, ?58). This water is found in the southeastern Hueco Bolson, north of the river; evaporation may be related to slow recharge through fine-grained sediment. Pre-dam water, recognizable by isotope composition, provides information on groundwater residence times in this and other dammed river basins.     

X射线荧光光谱法测定锌铝硅合金中硅和铁

采用岛津MXF-2400型多道X荧光光谱仪测定锌铝硅合金中硅及铁的含量,对样品分析面进行了选择,考察了分析面光洁度、样品放置时间对测定的影响条件。方法样品前期处理简便,分析速度快,灵敏度高,硅和铁的相对标准偏差(RSD,n=11)分别为1.15%和0.44%。与其他方法对照,结果相符。     

Identification of influencing factors for groundwater quality variation using multivariate analysis

This paper reports the results of multivariate analysis on the major-ions data present in groundwater collected in a hydrogeochemical survey of a hard rock terrain in Andhra Pradesh, India. The use of factor analysis is proposed, as a first step, for identifying the processes influencing the hydrogeochemical variations in groundwater. As a result of the application factor analysis, three factors were obtained, which explained characterization of groundwater quality and identified the sources for the presence of ions and its variations in concentrations and their geochemical processes. The natural dissolution of existing rocks of granites and granitic gneisses is the common influencing source for its hydrogeochemical character in the study area, but at some localized zones, the human-influenced sources of agricultural, industrial and urbanization are the dominating factors. The spatial and seasonal variation of the hydrogeochemical processes associated with the factor variables in the groundwater quality of the study area were analysed and evaluated.     

Magma sources and gold mineralisation in the Mount Leyshon and Tuckers Igneous Complexes, Queensland, Australia: U-Pb and Hf isotope evidence

In situ LAM-ICPMS U-Pb, Hf-isotope and trace-element analyses of zircon have been used to evaluate the relative contributions of juvenile mantle and crustal sources to the intrusive rocks of the mafic to intermediate, gold-poor Tuckers Igneous Complex (TIC), and the spatially and temporally related, felsic Mount Leyshon Igneous Complex (MLIC), which hosts a gold-rich porphyry system.

The TIC intrusions range in age from 304.2 ± 9.1 Ma to 288.5 ± 6.4 Ma, and the MLIC intrusions from 291.0 ± 4.8 Ma to 288 ± 6 Ma. Cross-cutting relationships define the intrusion sequence from oldest to youngest; Diorite, Monzodiorite, Mafic Granodiorite and Biotite Microgranite within the TIC; Early Dyke, Southern Porphyry and Late Dyke within the MLIC.

Zircons from the earliest rock type within each complex have a wide range in _Hf (5.2 to 14.8 for the TIC Diorite, 2.0 to 12.4 for the MLIC Early Dykes) suggesting the mixing of juvenile and crustal magmas. This interpretation is supported by trace-element data that show the presence of two distinct zircon populations in the MLIC Early Dyke. The later intrusive rocks have narrower ranges in _Hf (typically < 4 _Hf units) and trace-element patterns of zircon. This homogeneity suggests derivation from magmas produced by further mixing and fractional crystallisation of the TIC Diorite and the MLIC Early Dyke magmas respectively. A greater crustal contribution to the gold-rich MLIC is inferred from the range of median _Hf (3.2 to 4.5 for the MLIC, 5.4 to 8.7 for the TIC). We suggest that the MLIC was derived by melting of more felsic crustal rocks, and with less input from juvenile mantle, then the TIC; it was not derived by fractional crystallisation of an intermediate to mafic TIC-like magma. Modelling of Hf isotope data yields a mean model age of 1040 ± 10 Ma (at ¹⁷⁶Lu/¹⁷⁷Hf = 0.015) for the crustal component in both complexes.

Gold was precipitated in the MLIC Breccia during the emplacement of the Late Dykes. The isotopically homogenous nature of the Late Dykes suggests that no additional juvenile-mantle input was involved at the mineralisation stage. This supports a model in which gold and other metals were indigenous to the Late Dykes magma and were concentrated by magma differentiation and fluid-evolution processes.     

Sources of Mw 5+ earthquakes in northeastern Italy and western Slovenia: An updated view based on geological and seismological evidence

We present an overview of the seismogenic sources of northeastern Italy and western Slovenia, included in the last version of the Database of Individual Seismogenic Sources (DISS 3.0.2) and a new definition of the geometry of the Montello Source that will be included in the next release of the database. The seismogenic sources included in DISS are active faults capable of generating M_w > 5.5 earthquakes. We describe the method and the data used for their identification and characterization, discuss some implications for the seismic hazard and underline controversial points and open issues.In the Veneto–Friuli area (NE Italy), destructive earthquakes up to M_w 6.6 are generated by thrust faulting along N-dipping structures of the Eastern Southalpine Chain. Thrusting along the mountain front responds to about 2 mm/a of regional convergence, and it is associated with growing anticlines, tilted and uplifted Quaternary palaeolandsurfaces and forced drainage anomalies. In western Slovenia, dextral strike–slip faulting along the NW–SE trending structures of the Idrija Fault System dominates the seismic release. Activity and style of faulting are defined by recent earthquakes (e.g. the M_s 5.7, 1998 Bovec–Krn Mt. and the M_w 5.2, 2004 Kobarid earthquakes), while the related recent morphotectonic imprint is still a debated matter.We reinterpreted a large set of tectonic data and developed a segmentation model for the outermost Eastern Southalpine Chain thrust front. We also proposed the association of the four major shocks of the 1976 Friuli earthquake sequence with individual segments of three major thrust fronts. Although several sub-parallel active strike–slip strands exist in western Slovenia, we were able to positively identify only two segments of the Idrija Fault System. A comparison of the regional GPS velocity with long-term geological slip-rates of the seismogenic sources included in DISS shows that from a quarter to half of the deformation is absorbed along the external alignment of thrust faults in Veneto and western Friuli. The partitioning of the deformation in western Slovenia among the different strike–slip strands could not be quantified.     

地下水水质监测与评价

地下水由于分布广、水质好且开发费用低而成为全世界重要的供水水源。中国北方生活供水的一半来自地下水,地下水也是干旱期重要的农业灌溉水源。然而,地下水水质日益面临来自农业、工业和城市污染源的威胁。地下水水质监测是评价水质状况最可靠的方法,并可作为供水水源保护的早期预警系统。它为水管理部门和水用户提供可靠的科学数据以便更好地管理和保护地下水资源。世界上正在执行两个巨大的地下水质监测和评价项目:一个是欧盟的水框架计划;另一个是美国的国家水质评价计划。文章评述了地下水水质监测的现状,介绍了地下水易污性评价、地下水污染源分级和地下水污染风险评价的方法。地下水易污性分区图是土地利用规划和供水水源保护的基础。地下水污染源分级结果为污染源治理提供了优先顺序。地下水污染风险分区图圈划出地下水污染的高风险区,为地下水资源保护和地下水污染监测提供重要的依据。