埋深对恐龙化石的影响效果研究

已发现的恐龙化石大多数埋藏在不同深度的地层中,不同埋深化石所受风化破坏程度不尽相同。为深入研究恐龙化石的风化机理,探究恐龙化石的保护措施和方法,重点分析埋深产生的侧向压力对恐龙化石强度和破坏特性的影响。通过有限差分软件FLAC3D进行数值模拟,揭示埋深因素对恐龙化石保存的影响程度。试验结果表明:围岩对恐龙化石施加的侧向压力是影响恐龙化石变形和强度特性的一个重要因素。在弹性变形阶段,恐龙化石的初始强度、峰值强度随侧向压力的增大而不断增大。当应力超过了恐龙化石极限强度后进入塑性变形,其初始强度、峰值强度逐渐减小,最终达到残余强度。     

BOC调制信号多径误差分析

针对导航信号的多径误差分析,在多径误差包络曲线分析方法基础上提出了多径误差包络期望分析方法。与包络曲线分析方法相比,包络期望分析方法能够定量分析导航信号多径误差。基于包络期望分析方法,对同码速率的二进制偏移载波(BOC)调制导航信号与二进制相位控键(BPSK)调制导航信号的多径误差进行了对比分析。结果表明,BOC调制导航信号具有更小的典型多径误差。     

Impact of soil and water conservation measures on catchment hydrological response—a case in north Ethiopia

Impact studies of catchment management in the developing world rarely include detailed hydrological components. Here, changes in the hydrological response of a 200‐ha catchment in north Ethiopia are investigated. The management included various soil and water conservation measures such as the construction of dry masonry stone bunds and check dams, the abandonment of post‐harvest grazing, and the establishment of woody vegetation. Measurements at the catchment outlet indicated a runoff depth of 5 mm or a runoff coefficient (RC) of 1·6% in the rainy season of 2006. Combined with runoff measurements at plot scale, this allowed calculating the runoff curve number (CN) for various land uses and land management techniques. The pre‐implementation runoff depth was then predicted using the CN values and a ponding adjustment factor, representing the abstraction of runoff induced by the 242 check dams in gullies. Using the 2006 rainfall depths, the runoff depth for the 2000 land management situation was predicted to be 26·5 mm (RC = 8%), in line with current RCs of nearby catchments. Monitoring of the ground water level indicated a rise after catchment management. The yearly rise in water table after the onset of the rains (ΔT) relative to the water surplus (WS) over the same period increased between 2002–2003 (ΔT/WS = 3·4) and 2006 (ΔT/WS >11·1). Emerging wells and irrigation are other indicators for improved water supply in the managed catchment. Cropped fields in the gullies indicate that farmers are less frightened for the destructive effects of flash floods. Due to increased soil water content, the crop growing period is prolonged. It can be concluded that this catchment management has resulted in a higher infiltration rate and a reduction of direct runoff volume by 81% which has had a positive influence on the catchment water balance. Copyright © 2010 John Wiley & Sons, Ltd.     

Daily variability of river concentrations and fluxes: indicators based on the segmentation of the rating curve

The variability of water chemistry on a daily scale is rarely addressed due to the lack of records. Appropriate tools, such as typologies and dimensionless indicators, which permit comparisons between stations and between river materials, are missing. Such tools are developed here for daily concentrations (C), specific fluxes or yields (Y) and specific river flow (q). The data set includes 128 long‐term daily records, for suspended particulate matter (SPM), total dissolved solids (TDS), dissolved and total nutrients, totalling 1236 years of records. These 86 river basins (10³–10⁶ km²) cover a wide range of environmental conditions in semi‐arid and temperate regions. The segmentation—truncation of C–q rating curves into two parts at median flows (q₅₀) generates two exponents (b_50inf and b_50sup) that are different for 66% of the analysed rating curves. After segmentation, the analysis of records results in the definition of nine major C–q types combining concentrating, diluting or stable patterns, showing inflexions, chevron and U shapes. SPM and TDS are preferentially distributed among a few types, while dissolved and total nutrients are more widely distributed. Four dimensionless indicators of daily variability combine median (C₅₀, Y₅₀), extreme (C₉₉, Y₉₉) and flow‐weighted (C*, Y*) concentrations and yields (e.g. C₉₉/C₅₀, Y*/Y₅₀). They vary over two to four orders of magnitude in the analysed records, discriminating stations and river material. A second set of four indicators of relative variability [e.g. (Y*/Y₅₀)/(q*/q₅₀)], takes into account the daily flow variability, as expressed by q*/q₅₀ and q₉₉/q₅₀, which also vary over multiple orders of magnitude. The truncated exponent b_50sup is used to describe fluxes at higher flows accounting for 75% (TDS) to 97% (SPM) of interannual fluxes. It ranges from ? 0·61 to + 1·86 in the database. It can be regarded as the key amplificator (positive b_50sup) or reductor (negative b_50sup) of concentrations or yields variability. C₅₀, Y₅₀, b_50sup can also be estimated in discrete surveys, which provides a new perspective for quantifying and mapping water quality variability at daily scale. Copyright © 2011 John Wiley & Sons, Ltd.     

小秦岭含金石英脉中包裹体的热爆曲线特征及其找矿意义

应用自制的高性能爆裂仪能探测到小秦岭地区脉型金矿微小包裹体的热爆温度,探测到金矿成矿热流体的存在及其活动强度;根据包裹体热爆曲线特征判别岩石的含金性及区分富金矿石和贫金矿石,为金矿找矿与评价提供重要依据。     

航空摄影最佳曝光量的选择

分解力是评定影象质量的重要指标。本文介绍利用改进后的国产9 w测微密度仪,测定航空软片静态分解力与曝光量的关系。以最大分解力所相应的曝光量作为确定航摄软片感光度的基准,以此为基础,确定航摄底片的最大密度(D_(max))、最小密度(D_(min))、影象反差(△D)和平均密度(D_R)本文对国产1022T、1022P、柯达2402、2412等航摄软片进行了研究,其试验结果可作为今后修改航摄规范的基础。     

砂岩风化晕厚度在广东晚更新世测年中的应用

广东地区河流阶地和冲积扇沉积物中砂岩砾石风化晕随时间增厚。风化晕生长速度呈指数衰减,并拟合于下列公式:T 1485D4.13这里T=时间,以年表示,D=沉积物表部约50块砾石风化晕厚度的加权平均值,以毫米表示。利用风化晕厚度确定出广东地区河流第一和第二级阶地分别为1000—13300年和8600—26500年,肇庆盆地北部山前地带第Ⅰ和第Ⅱ级冲积扇分别为51500年和24400年。同时,在构造地貌变形分析的基础上,估算出本区三条主要北东向断裂带在晚更新世—中全新世的垂直断层作用速度为0.6—1.6毫米/年,中全新世甚或晚更新世晚期以来的活动速度极小     

非接触极化曲线视反应电位差区分矿体矿物成分及确定其边界的实验研究

本文用非接触极化曲线视反应电位差区分矿体矿物成分和确定矿体边界的基本原理，着重阐述矿物非接触极化曲线视反应电位差特征的实验研究方法和结果，并指出非接触极化曲线视反应电位差区分矿体矿物成分和确定矿体边界是有可能的。     

广东房地产业发展现状与前景分析

房地产开发热潮令理论界，新闻界和广大民众所关注，本文试图对广东省房地产发展的现状、特点及其主要问题作全面的分析，并提出解决问题的对策和建议，以及对广东省房地产业的发展前景作尝试性的探讨。     

机载合成孔径雷达图像频谱分析技术地质应用评价

频谱分析是空间滤波的一种。本文使用光学傅里叶变换分析SAR图像的空间频率特征。从取得的功率谱与功率谱角分布数据中可以:(1)确定与雷达后向散射方向有关面的走向最大(最小)方位角;(2)分析频谱曲线两个峰的夹角及其地学意义;(3)推算其水系密度;(4)研究样区地形基本特征。 这些资料有助于研究线性构造区域展布特征,岩类识别和地貌分类等。