固体介质中孤立波的传播及演化特征

由于地球介质中广泛存在断裂、微裂缝等地质现象,实际地震资料中会出现形似孤立波的非线性地震现象。因此,对固体介质中孤立波的研究有利于解释这些非线性地震现象的形成机制。本文基于KdV方程,以雷克子波作为初始条件,采用伸缩子机理构建体力模型,利用有限差分的方法模拟了孤立波的演化过程。理论结果表明,非线性地震纵波可以从雷克子波逐渐演化成孤立波,而且地震波的初始振幅和频散系数对模拟结果也有重要影响。通过与实际资料的对比也能说明这种演化的可能性。同时根据方程系数矩阵中元素带状分布的特征,采用稀疏矩阵的存取方法,可以减小计算内存,提高计算效率。     

用于地球物理反演的均匀设计优化算法

将均匀设计、模拟退火和单纯形方法相结合，提出一种全局优化迭代算法．数值模拟表明，它具有搜索速度快、搜索能力强和不需要求导数的特点，可用于地球物理反演研究．     

内蒙古河套地区土壤环境质量评价

土壤污染已成为抑制农业可持续发展的一个重要因素,土壤环境质量与研究区的地质条件、自然物理化学条件和人类活动有关。以河套地区多目标区域地球化学调查取得的表层土壤元素资料为依据,参照《土壤环境质量标准》(GB15618—1995)中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn分级标准,对研究区土壤的单元素环境质量进行分级并评价。以单元素土壤环境质量分级为基础,以单元素中最差的级别作为该单元土壤环境质量综合分级,评价研究区的土壤综合环境质量。通过单元素评价及综合评价认为,研究区内土壤环境质量总体状况优良,大部分地区为绿色、无公害的环境。     

京津冀夏季强降水下冰云宏微观特征

根据Aqua MODIS 2级云产品和Cloudsat的2级产品资料,结合降水数据和MODIS L1B级辐射率数据,对发生在京津冀地区夏季的三次强降水过程中冰云的宏微观物理量的特征进行分析,并探究这些物理量和降水强度的关系。结果表明：在水平分布中,强降水过程中降水强度高值区内云相为冰云,冰云云顶高度在8~17 km,冰云粒子有效半径、冰云光学厚度、冰水路径分别最高可达60 μm、 150、 5 000 g?m^-2;冰云光学厚度、冰水路径、冰云云顶高度随降水强度增大而增大。在垂直分布中,冰云主要分布在3.5 km以上,发生强降水站点的冰云为深对流云,冰云粒子有效半径、冰水含量、冰云粒子数浓度分别最高可达150 μm、 3 000 mg?m^-3 、 500 L^-1;冰云粒子有效半径高值区存在于云层中下部,且随高度上升而减小,冰云粒子数浓度高值区存在于云层中上部,且随高度上升而增加,冰水含量高值区则存在于云层中部;冰云粒子有效半径、冰水含量、冰云粒子数浓度在9 km以上随降水强度增大而增大。     

A generalized transformation approach for simulating steady-state variably-saturated subsurface flow

A numerical method is proposed to accurately and efficiently compute a direct steady-state solution of the nonlinear Richards equation. In the proposed method, the Kirchhoff integral transformation and a complementary transformation are applied to the governing equation in order to separate the nonlinear hyperbolic characteristic from the linear parabolic part. The separation allows the transformed governing equation to be applied to partially- to fully-saturated systems with arbitrary constitutive relations between primary (pressure head) and secondary variables (relative permeability). The transformed governing equation is then discretized with control volume finite difference/finite element approximations, followed by inverse transformation. The approach is compared to analytical and other numerical approaches for variably-saturated flow in 1-D and 3-D domains. The results clearly demonstrate that the approach is not only more computationally efficient but also more accurate than traditional numerical solutions. The approach is also applied to an example flow problem involving a regional-scale variably-saturated heterogeneous system, where the vadose zone is up to 1 km thick. The performance, stability, and effectiveness of the transform approach is exemplified for this complex heterogeneous example, which is typical of many problems encountered in the field. It is shown that computational performance can be enhanced by several orders of magnitude with the described integral transformation approach.     

Estimating open boundary conditions from coastal tidal observations by adjoint approach

A numerical study for estimating the tidal open boundary conditions of a shelf current modrl from tb coastal tidal observations is presented. The method is based on the optimal control/adjoint method. A lrast square fitting of the model state to simulated data is used. Two ideal domains and coastlines are considered. Using the IAP shallow. water model and its adjoint model, some identical twin experiments are carried out to test efficiency and lirnilsd of the method. The results show that the adjoint method can efficiently estimate the open boundary conditions well for gulf/bay like domains. The adjoint method seems to have great potential to improve the accuracy of tide and shelf current modeling in coastal regions. Project supported hy the National Natural Science Fuundation of China (Grant No. 49376256)     

FS方法及其在综合多项震兆中的应用

本文提出了一种模式识别方法--FS方法.该方法的特征取为某些论域上的模糊子集.先以每三个原始特征组成子分类器的特征集,“训练”这些分类器,然后对子分类器进行筛选,最后用筛选出的子分类器的“软”分类结果的加权平均作为判别函数,形成总的分类决策.将FS方法应用于综合多项震兆,并进行了一系列控制试验,还与地震学中几种常用的方法进行了对比试验.结果表明,FS方法是稳定和有效的.     

A synthetic aperture radar sea surface distribution estimation by n-order Bézier curve and its application in ship detection

To dates,most ship detection approaches for single-pol synthetic aperture radar(SAR) imagery try to ensure a constant false-alarm rate(CFAR).A high performance ship detector relies on two key components:an accurate estimation to a sea surface distribution and a fine designed CFAR algorithm.First,a novel nonparametric sea surface distribution estimation method is developed based on n-order Bézier curve.To estimate the sea surface distribution using n-order Bézier curve,an explicit analytical solution is derived based on a least square optimization,and the optimal selection also is presented to two essential parameters,the order n of Bézier curve and the number m of sample points.Next,to validate the ship detection performance of the estimated sea surface distribution,the estimated sea surface distribution by n-order Bézier curve is combined with a cell averaging CFAR(CA-CFAR).To eliminate the possible interfering ship targets in background window,an improved automatic censoring method is applied.Comprehensive experiments prove that in terms of sea surface estimation performance,the proposed method is as good as a traditional nonparametric Parzen window kernel method,and in most cases,outperforms two widely used parametric methods,K and G0 models.In terms of computation speed,a major advantage of the proposed estimation method is the time consuming only depended on the number m of sample points while independent of imagery size,which makes it can achieve a significant speed improvement to the Parzen window kernel method,and in some cases,it is even faster than two parametric methods.In terms of ship detection performance,the experiments show that the ship detector which constructed by the proposed sea surface distribution model and the given CA-CFAR algorithm has wide adaptability to different SAR sensors,resolutions and sea surface homogeneities and obtains a leading performance on the test dataset.     

Preparation of Mg/Al Layered Double Hydroxides by Buffer Solution Method and Cr（Ⅵ） Adsorption Characteristics

利用氨水-氯化铵体系在pH 9～10时具有缓冲能力的特点,以其作为沉淀剂成功合成了镁铝水滑石（Mg3Al-Cl-LDHs）,采用XRD、FT-IR、TG-DTA等手段对材料结构进行表征,并测试了合成Mg3Al-Cl-LDHs样品对溶液中Cr（Ⅵ）的吸附性能。研究结果表明,缓冲溶液法制备的Mg3Al-Cl-LDHs材料晶相单一,晶面生长的有序程度较高,结晶度较好。晶胞参数a=0.3106 nm,c=2.367 nm,粒子尺寸约为36.44 nm。其热分解过程包括水滑石层间结构水脱除和层板羟基脱水、氯离子分解两个步骤。Mg3Al-Cl-LDHs对Cr（Ⅵ）的吸附主要发生在0～1 h内,随着时间的增长吸附量先增加后趋于平缓;温度对Cr（Ⅵ）吸附量影响不大,在常温下即可进行;随着pH值的减小,饱和吸附量先增大后减小,在pH 6时吸附效果较好;2价与3价竞争阴离子比1价阴离子对吸附性能的影响更大。在最佳吸附条件下,Mg3Al-Cl-LDHs对Cr（Ⅵ）的饱和吸附量可达58.73 mg/g,有望应用于实际Cr（Ⅵ）废水处理。     

大港滩海区埕北断阶带古近系层序界面的识别方法

通过对大港滩海区埕北断阶带层序地层的研究，将研究区古近系划分为3个三级层序，总结了5种识别层序界面的方法：①地震识别法；②钻井识别法；③测井识别法；④古生物组合识别法；⑤地球化学识别法。在研究区，方法①表现为区域性的上超和削截；方法②表现为岩性和泥岩颜色的突变；方法③表现为各种曲线和地层倾角的突变；方法④表现为古生物组合类型的变化；方法⑤表现为Fe^2＋／Mn^2＋值由下向上由逐渐增大，转为突然变小。其中方法①、③、④是层序界面的主要识别标志，方法②可作为参考标志，而方法⑤的应用效果较差。