城市化影响地下水水质的正负效应

以石家庄市为例, 通过城市化水平和地下水污染态势的定量计算、分析, 对城市化影响地下水水质的机理及其正负效应进行了探讨.结果表明: 石家庄城市化发展处于初级阶段; 城市化影响地下水水质有正负两方面的效应, 城市化水平的提高, 有助于改善地下水水质, 但却易于加剧地下水盐污染.本研究为以地下水作为主要、甚至唯一供水水源城市的可持续发展提供了一种理论和根本途径.      

可变电荷土壤和恒电荷土壤与氢离子相互作用机理

研究了可变电荷土壤和恒电荷土壤与H相互作用的机理，并比较了它们之间的差别，研究结果表明，氢离子输入土壤后可以转化为表面正电荷，可溶性铝和可交换性酸，但是由于土壤的组成和性质不同，不同土壤中H＋三种去向的贡献不同。H＋转化为表面正电荷是由于土壤表面Fe-OH,Al-OH的质子化造成的，因此H＋转化为表面正电荷的能力与土壤中氧化铁的含量密切相关，从而可变电荷土壤中H＋转化为表面正电荷的贡献比恒电荷土壤中的大。H＋转化为可溶性铝的能力与土教育部 的矿物组成密切相关，随着H＋输入量的增加，土壤中可溶性铝的含量也增加。可变电荷土壤中可溶性铝增加的顺序为红壤＞赤红壤＞铁质砖红壤，在H＋的加入量小于15mmol/kg时，黄棕壤的可溶性铝介于红壤和赤红壤之间，当H＋的加入量大于约15mmol/kg时，黄棕壤的可溶性铝略小于赤红壤，棕壤的可溶性铝明显小于红壤和赤红壤，但比铁质砖红壤高，恒电荷土壤的可变性酸量明显大于可变电荷土壤，但从总的看来，H＋加入量的变化对可交换性酸量的影响不大。     

塔西南坳陷甫沙构造带正反转构造及其石油地质意义

塔西南坳陷甫沙构造带褶皱冲断强烈,古近系膏泥岩下层构造变形复杂,具有正反转构造变形特征。侏罗纪—白垩纪区域伸展环境发育大量正断层,后期在喜马拉雅运动中受挤压反转。南部发育高角度基底卷入正反转断层,中部发育叠瓦式逆冲断层,北部边缘变形微弱。相应地将甫沙构造带划分为反转断隆背斜带、楔状叠瓦构造带和逆冲前缘构造带;反转程度南强北弱、西强东弱。对区域构造变形环境的分析表明,西昆仑山隆升引发水平挤压叠加垂直向上的剪切作用,使先存高角度正断层容易被迁就利用进而发生正反转。对正反转相关构造圈闭评价认为:反转断隆背斜带发育的圈闭规模大,幅度低,埋藏浅,落实程度高,但上覆膏泥岩层薄,被断层破坏强烈,油气散失严重;楔状叠瓦构造带发育的圈闭规模小,幅度大,埋藏深,落实程度低,上覆膏泥岩层厚,有利于油气保存;逆冲前缘构造带发育低幅度隆起和地层岩性圈闭。     

Representations of inverse covariances by differential operators

In the cost function of three- or four-dimensional variational data assimilation, each term is weighted by the inverse of its associated error covariance matrix and the background error covariance matrix is usually much larger than the other covariance matrices. Although the background error covariances are traditionally normalized and parameterized by simple smooth homogeneous correlation functions, the covariance matrices constructed from these correlation functions are often too large to be inverted or even manipulated. It is thus desirable to find direct representations of the inverses of background error correlations. This problem is studied in this paper. In particular, it is shown that the background term can be written into f dx|Dv(x)|^2, that is, a squared L2 norm of a vector differential operator D, called the D-operator, applied to the field of analysis increment v(x). For autoregressive correlation functions, the D-operators are of finite orders. For Gaussian correlation functions, the D-operators are of infinite order. For practical applications, the Gaussian D-operators must be truncated to finite orders. The truncation errors are found to be small even when the Gaussian D-operators are truncated to low orders. With a truncated D-operator, the background term can be easily constructed with neither inversion nor direct calculation of the covariance matrix. D-operators are also derived for non-Gaussian correlations and transformed into non-isotropic forms.     

FURTHER STUDY ON THE PROPERTIES OF OPERATORS OF ATMOSPHERIC EQUATIONS AND THE EXISTENCE OF ATTRACTOR

The equivalent operator equation is derived from the full primitive nonlinear equations of theatmospheric motion and the properties and physical senses of the operators are studied.In theinfinite dimensional Hilbert space,the global asymptotic behavior of the atmosphere system withthe non-stationary external forcing is studied under the assumption of the bounded externalforcing.The existence theorems of the global absorbing set and the global attractor are obtained.Thus,the conclusions deduced from the large-scale atmosphere(Li and Chou 1996 a;1996 b)areextended to the general atmosphere.     

Nonlinear coupled analysis of a single point mooring system

Coupled effects on a single point mooring(SPM) system subjected to the combined action of wind,waves and current are studied in this paper. Due to the complicatedness of the sea state and the huge size of the vessel,physical experimental study is both time consuming and uneconomical,whereas the numerical study is cost-effective and DNV software provides powerful SESAM software in solving the issues. This paper focuses on the modeling process of the SPM system,catenary equilibrium calculation,static analysis of the vessel in three different scenarios,and dynamic response simulation of the SPM system under environmental excitations. The three scenarios in study are as follows:the SPM is under the combined function of(a) wind,waves and current,(b) wind and waves,(c) current and waves. They are so set that one can compare the contributions of different types of loads in both static and dynamic studies. Numerical study shows that wind and current are the two major factors contributing to the mooring line tension,and surge and sway are the two dominant motions of the moored vessel subjected to environmental excitations.     

基于VB的测量坐标正算与反算研究

坐标正反算在测量实际工作中经常用到,本文介绍了测量坐标正算与反算的数学模型,采用VB开发语言,设计了测量坐标正算与反算程序,为测绘工作中坐标转换提供了思路。     

机载碘化银发生器燃烧室残留物成分分析

通过对碘化银发生器残留物样本化学分析,残留物附着规律及其成因研究,最后提出了减少残留物的对策。     

一种基于角点特征的遥感影像自动配准方法

本文通过对Harris算子进行改进,自适应地提取角点特征,然后基于角点特征进行由粗到精的匹配,完成影像的配准;并利用MODIS影像、TM影像和HJ-1卫星影像3种不同分辨率的遥感影像进行配准实验,结果表明该自动配准方法能够达到亚像素级的配准精度,是一种高精度的影像配准方法。     

浙江省沿海陆域与舟山海域地闪回击特征分析

采用2016-2020年浙江省闪电定位资料,利用Access和MATLAB对浙江省陆域、舟山海域地闪回击特征进行分析.结果显示:浙江省陆域年平均地闪回击密度为1.97次·km-2·a-1,正地闪回击密度为0.10次·km-2·a-1,正地闪回击占总地闪回击的5.1％,正地闪回击平均电流强度为42.49 kA,负地闪为3...