一阶

The Lower/Upper Cretaceous boundary in Songliao Basin is,therefore,between the Quantou and Denglouku formations,instead of between the Quantou and Qingshankou formations.2.The dark mudstones and shales in the Member 1 of Qingshankou Formation are of high organic carbon and low diasteranes contents.Organic geochemical characters are illustrated by biomarkers of 28,30-bisnorhopane and gammacerane,and positive excursion of kerogen isotopes.It is suggested that the dark mudstones and shales in the Member 1 of Qingshankou Formation are the products of lake anoxic period.It corresponds to the oceanic anoxic event at Cenomanian-Turonian boundary in Cretaceous.3.Based on the study of biostratigraphy,chronostratigraphy,magnetostratigraphy and event stratigraphy,a correlation of the lacustrine sequence to marine standard has been proposed,i.e.,the Quantou Formation corresponds to Cenomanian stage,Qingshankou Formation correlates to Later Cenomanian-Early Turonian,Yaojia Formation to Later Turonian-Coniacian,Nenjiang Formation to Santonian-Campanian.Sifangtai and Minshui Formations to Maastrichtian. 4.Analysis of lithology,lithofacies and microfossils of Cretaceous in Songliao Basin, shows that shore and shallow lake facies yield the most abundant microfossil groups,and the predelta and deltaic distributary plain facies rich in fossils as well.In the shore and shallow lake areas during the high level periods(such as Qingshankou and Nenjiang sedimentary periods),the lacustrine biota are of high diversity and high abundance.

因此，松辽盆地上、下白垩统的界线应在泉头组的底界，即泉头组与登娄库组之间，而不是泉头组的顶界。2、青山口组一段黑色泥岩、页岩具有有机碳含量高、重排甾烷含量低，生物标志物出现28，30—双降藿烷和伽马蜡烷，干酷根碳同位素具有正向偏移等有机地球化学特征，表征为青山口组一段黑色页岩、油页岩是古湖泊缺氧事件的产物，它对应于白垩纪古海洋Cenomanian—Turonian期界线附近缺氧事件，二者具同步性。3、通过生物地层学、年代地层学、磁性地层学和事件地层学研究，认为泉头阶大体相当于Cenomanian阶，青山口阶相当于晚Cenomanian—早Turonian阶，姚家阶对应于晚Turonian—Coniacian阶，嫩江阶对应于Santonian—Campanian阶，四方台阶和明水阶相当于Maastrichtian阶。4、通过对松辽盆地上白垩统的岩性、岩相及微体化石分析，认为滨浅湖相是微体生物群最为发育的相带，其次为三角洲前缘相和三角洲分流平原相。

The paper has used concise methods of logical analysis and reasoning to describe the relation between the first-order quasilinear partial differential equation and its system of characteristic equation.

对一阶拟线性偏微分方程与其特征方程组的关系，文中给出了简洁的逻辑分析和推导方法。

In Chapter 4, by means of the result obtained in Chapter 2 and as in the autonomous case, the author adopts a direct constructive method and obtains the local exact controllability for general nonautonomous first order quasilinear hyperbolic systems.

在第四章，作者以第三章建立起来的半整体C~1解理论为基础，采用一个与自治系统情况相似的直接构造方法得到了非自治一阶拟线性双曲组的局部精确能控性。

The spreading mechanism of the Bragg lines in shipborne HFSWR is analyzed and mathematical spreading model is given.

理论分析了舰载 HFSWR 一阶海杂波谱的展宽机理，给出其展宽数学模型。

First,the 3-d dynamic equations in cylindrical coordinate for transversely isotropic saturated soil were transformed into a group of governing differential equations with 1-order by the technique of Fourier expanding with respect to azimuth,and the state equation was established by Hankel integral transform method,furthermore the transfer matrixes within layered media were deriv...

首先，通过方位角的Fourier变换，将圆柱坐标系下横观各向同性饱和土的三维动力方程转化为一阶常微分方程组，基于径向Hankel变换，建立问题的状态方程，求解状态方程后得到传递矩阵；其次，利用传递矩阵，结合层状饱和地基的边界条件、排水条件及层间接触和连续条件，给出了任意简谐激振力作用下层状横观各向同性饱和地基动力响应的通解；然后，按混合边值问题建立层状饱和地基上弹性圆板非轴对称振动的对偶积分方程，并将对偶积分方程化为易于数值计算的第二类Fredholm积分方程，并给出了算例。

In order to get the optimal solution of an inverse problem,we analyse systematically the double perturbation processing technique, the first order Bor...

为了得到反问题的最优解，文中系统地研究了层状介质中双摄动处理技术，以及层状介质中波场摄动的一阶 Born 近似解与理论重力异常摄动解。

Magnetotelluric field finite difference migration tomography Found on the researches of Zhdanov etc. in MT finite difference migration tomography, we analyze and summarize both fruits and limitation of foregone peoples' achievements. So more precise finite difference extrapolation equation can be deduced, and it can be easily applied into the migration tomography. New equation reserved the derivative terms of wave number both at vertical and horizontal direction, so that more exquisite geoelectric diversification can still be accommodated, that is the very requirement of practical data interpolation.

大地电磁有限差分偏移成像技术：在Zhdanov等人建立的有限差分偏移成像研究的基础上，总结分析了前人在 MT成像技术方面的研究成果和存在问题；推导更精确的有限差分波场延拓方程，采用改进的有限差分法进行大地电磁场偏移成像，差分延拓方程保留波数对水平方向和垂直方向的一阶导数项而提高求解精度，可适应电性纵横方向变化剧烈的地电构造，使成像分辨率得到增强。

Defining a Tapered Beam）.The beam elements are based on Timoshenko beam theory, which is a first

单元基于铁木辛哥梁理论，这个理论是一阶剪切变形理论；横向剪切应力在横截

In this paper, two-point ray tracing is studied for three-dimensional arbitrary interface. from Fermat's principle, traveltime is expanded in the initial ray path according to one order Taylor's incompletion expansion. Then, the algorithm of total iterative ray tracing in three dimension is derived.

作者在文中对三维任意界面情况下的两点间射线追踪问题进行了研究，从Fermat原理出发，对射线路径上的旅行时，采用一阶Taylor不完全展开等办法，推出了三维情况下计算射线路径的整体迭代算法。

Fermat's principle: The raypath which seismic energy will follow between two points is that for which the first order variation with all neighboring paths is zero.

费马原理：两点之间地震波传播的射线路径，它与相邻路径的一阶差分为零。

The labia have now been sutured together almost completely.The drains and the Foley catheter come out at the top.

此刻阴唇已经几乎完全的缝在一起了，排除多余淤血体液的管子和Foley导管从顶端冒出来。

To get the business done, I suggest we split the difference in price.

为了做成这笔生意，我建议我们在价格上大家各让一半。