大渡河安宁水电站深厚覆盖层勘探技术与方法

介绍了大渡河上游安宁水电站可研阶段河床深厚覆盖层勘探所用的技术与方法：φ130植物胶钻具钻进工艺、φ139厚壁套管跟管钻进工艺、多级跟管钻头钻进工艺;还介绍了覆盖层钻孔孔内旁压试验和原状砂样的采取技术。本阶段深厚覆盖层勘探中应用的技术与方法保证了勘探工作的圆满完成,为计算和设计提供了详实、可靠、全面的参数,同时也完善勘探技术与内容,提高了勘探水平,为今后的勘探工作作了相应的技术储备。     

甘肃文县阳山矿区复杂地层用冲洗液研究

介绍了甘肃文县阳山矿区泡沫冲洗液和HJ-YS系列冲洗液的研制与应用。以42线ZK706孔和51线ZK3002、ZK3016、ZKN3084、ZK0204钻孔为例,首先介绍了泡沫冲洗液在孔壁失稳地层的应用效果;其次介绍了低固相植物胶HJ-YS系列冲洗液对破碎强烈、多溶洞、易漏失、水敏性强、采心困难的复杂地层所具有的良好的润滑减阻和护壁堵漏效果。     

Numerical modeling of heterogeneous flow fields around rigid objects with special reference to particle paths, strain shadows and foliation drag

With the help of two-dimensional numerical models this paper investigates three aspects of heterogeneous deformation around rigid objects: (1) the nature of particle paths; (2) the development of strain shadow zones; and (3) the drag patterns of passive markers. In simple shear, spherical objects develop typically a concentric vortex motion, showing particle paths with an eye (double-bulge)-shaped separatrix. The separatrix has no finite dimension along the central line, parallel to the shear direction. Under a combination of pure shear and simple shear, the particle paths assume a pattern with a bow-tie shaped separatrix. With increase in the ratio of pure shear to simple shear (S_r), the separatrix around the object shrinks in size. The axial ratio of the object (R) is another important factor that controls the geometry of particle paths. When R<1.5, the loci of a particle close to the object form an elliptical shell with the long axis lying along the central line. With increase in axial ratio R, the loci form a doublet elliptical shell structure. Objects with R>3 do not show closed particle paths, but give rise to elliptical or circular spiral particle paths.

The development of strain shadow zones against equant rigid bodies depends strongly on the strain ratio S_r. When S_r=0 (simple shear), they develop opposite to the extensional faces of the object, forming a typical σ-type tail. The structure has a tendency to die out with an increase in the pure shear component of the bulk deformation (S_r). The initial angle of the long axis of the object with the shear direction (φ) and the axial ratio of the object (R) determine the development of strain shadow zones near inequant rigid objects. Objects with large R and φ between 60 and 120° form pronounced zones of low finite strain, giving rise to strain shadow structures. A geometrical classification of diverse drag patterns of passive markers around rigid objects is presented along with their conditions of formation.     

陆上纵波源VSP资料中的纯横波

常规陆上VSP(Vertical Seismic Profiling)勘探普遍采用纵波震源激发,三分量检波器接收,主要利用的是纵波和转换横波信息。已有的研究表明,炸药震源在井下激发、可控震源在地面垂向振动,均会产生较强的纯纵波和一定强度的纯横波;泊松比差别较大的分界面有利于形成较强的透射转换横波。本文通过对激发形成的纯横波和下行转换形成的横波进行对比分析,认为纯横波的主频往往低于纯纵波的主频,而下行转换横波的主频通常接近纵波的主频。本文分别对两个陆上纵波源零偏和非零偏VSP资料进行分析,结果表明这些资料中普遍存在纯横波,只是横波的强弱存在不同程度的变化。利用纵波源零偏VSP资料,可以获得横波速度信。最后对VSP纵波和横波联合应用前景进行了分析,应该充分利用纵波源VSP资料中的横波信息。     

当前矿泉水界需要重视的几个问题

判别真假矿泉水的主要责任应该在行政主管部门和执法管理部门，矿泉水应具备国家标准中指列的要求。瓶装矿泉水“宜冷藏不宜冷冻”，冷冻出现沉淀也无土方。矿泉水不存在“有害元素含量的抑制”问题，偏离规定的矿泉水开发是非法的。纯净水应有准确的定义或含义，目前市场上的纯净水具有可变性，“纯净”的跨度很大，名称繁多，商家的广告缺乏科学性，使人莫明其解，瓶装水都应在平等条件下竞争，行政主管部门应加强管理。     

基于MODIS GPP产品的冬小麦保险费率厘定方法研究

农作物保险是国内外减少灾害造成的种植户经济损失,保障农民基本生产收入的重要手段。国内传统的农作物保险费率是基于行政单元的统计数据厘定的,忽略了行政单元内部灾害的空间风险差异,因此如何获得行政单元内部农户级农作物纯保险费率,成为精细化农作物保险的关键问题。本文针对农户级的冬小麦纯保险费率,以河南省周口市为实验区,利用2005—2015年MODIS MOD17 A2 GPP总初级生产力数据产品生成2005—2015年冬小麦生长季的GPP数据,同时利用Landsat5/7/8 TM/ETM/OLI数据计算2005—2015年公里级的冬小麦种植面积比。通过Bühlmann-Straub模型和经验费率法厘定得到2016年实验区基于格网单元的冬小麦纯保险费率。研究表明：遥感数据可以为农作物保险空间精细费率厘定提供数据保障,利用遥感数据可以得到公里级格网单元的冬小麦纯保险费率。将利用遥感数据得到的农作物纯保险费率用于农作物保险中,提高了农作物保险的空间精细水平,可以进行基于地块的空间差异化农户投保,有利于政府针对不同农户制定合理的农作物保险政策,保险公司合理的收取保费。     

基于动态NDSI阈值的每日积雪监测方法

准确掌握积雪覆盖信息对于气象、水文和全球气候变化研究都具有重要的意义。遥感技术在进行大范围、高频率的积雪覆盖监测中发挥着重要的作用。目前,SNOMAP算法是用于积雪遥感监测最普遍的技术手段,其核心是利用固定阈值的归一化差分积雪指数（Normalized Difference Snow Index,NDSI）进行积雪识别,但这种方法忽略了积雪光谱信息的时相变化,会产生积雪监测的误差。本文提出了一种动态NDSI阈值方法,以纯永久积雪像元的平均NDSI值作为参照系调整固定的NDSI阈值,从而削减影像光谱值波动对积雪识别的影响。以三江源地区作为研究区域,将基于每日MODIS数据进行积雪监测最佳的NDSI阈值与同日纯永久积雪像元的平均NDSI值作线性回归,通过每日纯永久积雪像元平均NDSI值的变化来调整用于积雪识别的NDSI阈值。结果表明：① 基于每日MODIS数据进行积雪覆盖监测最佳的NDSI阈值与同日纯永久积雪像元的平均NDSI值之间存在较好的线性关系,决定系数R ²达到0.86;② 三江源地区动态NDSI阈值的范围为0.29~0.37,其平均值在0.33左右,说明MODIS全球积雪面积产品中将NDSI阈值取为0.40会低估三江源地区的积雪面积;③ 与采用固定NDSI阈值0.33的监测方法相比,动态NDSI阈值法近似率、总体分类精度和F值的平均值分别提高了5.17%、0.70%、1.14%。     

Formation of dome and basin structures: Results from scaled experiments using non-linear rock analogues

Dome and basin folds are structures with circular or slightly elongate outcrop patterns, which can form during single- and polyphase deformation in various tectonic settings. We used power-law viscous rock analogues to simulate single-phase dome-and-basin folding of rocks undergoing dislocation creep. The viscosity ratio between a single competent layer and incompetent matrix was 5, and the stress exponent of both materials was 7. The samples underwent layer-parallel shortening under bulk pure constriction.Increasing initial layer thickness resulted in a decrease in the number of domes and basins and an increase in amplitude, A, arc-length, L, wavelength, λ, and layer thickness, H_f. Samples deformed incrementally show progressive development of domes and basins until a strain of e_Y=Z = −30% is attained. During the dome-and-basin formation the layer thickened permanently, while A, L, and λ increased. A dominant wavelength was not attained. The normalized amplitude (A/λ) increased almost linearly reaching a maximum of 0.12 at e_Y=Z = −30%. During the last increment of shortening (e_Y=Z = −30 to −40%) the domes and basins did not further grow, but were overprinted by a second generation of non-cylindrical folds. Most of the geometrical parameters of the previously formed domes and basins behaved stable or decreased during this phase. The normalized arc-length (L/H_f) of domes and basins is significantly higher than that of 2D cylindrical folds. For this reason, the normalized arc length can probably be used to identify domes and basins in the field, even if these structures are not fully exposed in 3D.