成层的

Objective: To study the method and clinical application value of multi-slice CT in brain blood vessel resemble .

目的：探讨多层螺旋CT脑血管成像的方法与临床应用价值。

Firstly, a balance equation is erected, And then,on the basis of the predecessor formula and with the Convolution Theorem and Fourier inverse transforms,a semi-analytical solution of the velocity response in time-domain under semi-sine exciting force is given.

建立成层土中桩纵向振动平衡方程，利用卷积定理和傅立叶逆变换求得半正弦脉冲激振作用下桩顶速度响应的半解析解。

Objective To evaluate the clinical values of 16?slice spiral computed tomography coronary angiography.

目的评价16层CT冠状动脉成像的临床价值。

Concept data model of MRGISDM analyses entity's character and relationship. Logic data model designs logical and geometric representation of entity and relathionship; physical data model designs the schema of classification and coding ,orgnization of layers,and physical storage structure.

在MRGISDM概念模型中确定了市政道路中需要表达的要素实体，提取出每个要素实体的属性，并描述出实体之间的关系；MRGISDM逻辑模型则把市政道路实体以及实体之间的关系表达成地理信息系统所能识别的方式，并用UML语言等工具描述成UML逻辑模型图；MRGISDM物理模型从市政道路要素的分类与编码、图层的组织以及物理表结构等几个方面来设计市政道路要素的组织和存储结构。

Early diagenesis has broad and bright prospects not only in theory but also in application, and three future trends are predicted. First, the area of early diagenesis study will be enlarged widely to lake, delta, soil. Then, the stable or nonstable one-dimensional, two-dimensional or three-dimensional multi-layer early diagenesis models will be established, and the methods and theoretical achievements of early diagenesis will be widely applied in environmental sedimentology to supervise and treat environment pollution.

早期成岩作用研究具有广阔的发展前景，未来可能在以下3方面快速取得突破：研究区域将进一步扩大，湖泊、三角洲及土壤中的相应研究将得以加强；多层的稳态或非稳态的一维、二维或三维的早期成岩数学模型将得以建立；其研究方法和理论成果将被广泛应用于环境沉积学及环境监测和治理等领域中。

Hierarchical linear modeling is the most frequently used technique for analyzing multilevel data. In this paper, the twelve key issues in multilevel research and/or using HLM software were reviewed, and provided their exact meanings and feasible solutions. The 12 key issues included intraclass correlation coefficient, sample sizes, formation of organizational constructs, centering problems, fixed effect and random effect, estimation methods, goodness of fit index, explained variation, multicollinearity, robust standard error, level one variance equation, and empirical Bayes estimates.

本文针对阶层线性模式在多层次研究上有关於技术、测量与方法论所遭遇的问题，进行文献整理并讨论其实务意涵，并依据使用时机、抽样议题、资料汇总、分析方法、与模式评估与估算等五方面整理出十二项重要议题与解决之道，包括：组内相关系数的意义与判断准则、多层次研究各层的样本数问题、变数聚合成组织层次问题、中心化的意义、固定效果与随机效果的设定、估计法的选择、适配度的比较、解释变异量的计算、多元共线性的分析、强韧性标准误、第一层误差项变异数与实证贝氏估计值的运用。

Based on above studies, some main conclusions were obtained as follows : 1 the diatoms forming mats in low latitude west pacific is"shade flora"diatom Ethmodiscus rex Hendey; 2 the sites found diatom mats are zone distributed, the direction is NW-SE and most distribute in the deep water area with flat seafloor, between 17°N～20°N and the water depth 4837-6150 m below Carbonate Compensation Depth (CCD 3) AMS 14C dates show that the sediments rich in diatom mats occurred during 16.0 ~ 28.6 ka B.P., which means the bloom mainly occurred in last glacial maximum, while there are not diatom mats deposits in other layers; 4 A total of 101 diatom taxa belonging to 40 genera had been identified from the 155 samples in the two cores WPD 03 and WPD 12, and the relative percentage of Thalassionema frauenfeldii are the highest, Thalassionema nitzschioides、Azpeitia nodulifera、Hemidiscus cuneiformis、Nitzschia marina take the second place.

14C年期间，即&勃发&发生于末次冰期最盛期；4在WPD 03和WPD 12两个岩芯共155个样品中共鉴定硅藻40属101种，且Thalassionema frauenfeldii的相对百分含量最高，Thalassionema nitzschioides、Azpeitia nodulifera、Nitzschia marina、Hemidiscus cuneiformis等次之，这五种硅藻占整个硅藻物种相对百分含量的85%左右，说明在该海域表层水体硅藻席沉积过程中，这五种硅藻最容易与成席硅藻在同时期的环境中生存，形成勃发；5MIS3期的晚期，该区域表层海水盐度降低，这有助于该区水体的成层化，从而使&树荫种&硅藻开始勃发，导致&秋季倾泻&；6末次冰期由于南极中层水北扩，南大洋中层水将富含硅酸盐的海水带入了研究区，即南大洋的&硅溢漏&作用，使该区域硅藻得以勃发，同时，铁输入的增多，可能也是造成硅藻勃发的主要原因之一。

Notch1 is expressed by stem cells resided in the cervical loop epithelium, and Notch signaling pathway play a central role in fate decision of those stem cells. Notch receptors and their ligands are involved in both patterning and cell fate determination during odontogenesis. Moreover, many cell factors, which are closely related with odontogenesis, could regulate expression of Notch receptors or their ligands.

既往研究显示：早在牙齿发育期，Notch1就表达于颈环星网状层的干细胞中，是其保持干细胞性质的重要机制；Notch-Delta信号还与成釉细胞、成牙本质细胞分化有关，被认为是牙齿发育细胞分化多样性的原因之一；另外，目前已明确与牙胚细胞分化有关的生长因子如TGFβ、FGF、BMPs等均可诱导Notch受、配体的表达。

In the process of building and using the mass concrete structures, because of the effect of out-side condition and themselves, some faults will form in the structure, these faults will effect the bearing capability and endurance Using nondestructive testing method to test the concrete"s quality and diagnose its healthy, which has the significant sense in assessing the safety stability and research of the administering diseasesThis dissertation mostly researched the testing methods in the mass concrete structure, discussed the principles, methods, features, sphere of application of the ultrasonic testing in the mass concrete structure with faults, used dynamic FEM to simulate the testing process, discussed when the concrete structure with cracks is under the effect of the pulse, how the elastic waves propagate and what are their changing feature, Researched the principles of the first-arriving waves" phase when the cracks" depths are not same, obtained the relation between the inversion point and the cracks" depth, which has the direction sense in the application of projects,The second part of this dissertation is CT , which used the ultrasonic wave running through the tested-substance to get arriving-time of the ultrasonic wave, then inverse the image This dissertation drawed one CT program which can well present the different little cells ultrasonic wave velocity profiles of the substance, thereby to diagnose the quality of the part of the tested-substance, CT has the better using foreground..

在混凝土结构的施工及使用过程中，由于受其自身及外界各种因素的影响，常常会产生一些缺陷，对结构物的承载能力和耐久性造成严重影响，采用无损检测技术进行质量检测和健康诊断，这对混凝土结构开展安全、稳定性评估以及病害隐患治理研究具有重要意义。本论文主要针对大体积混凝土结构缺陷的检测方法展开研究工作，重点讨论了超声波法检测混凝土结构裂缝的基本原理和方法及其特点、适用范围，运用动力有限元数值模拟其检测过程，探讨了有裂缝缺陷的混凝土结构在脉冲荷载作用下弹性波的传播及其变化特征，研究了不同裂缝深度下首波相位变化规律，得出了反转临界点与裂缝深度之间的关系，这对实际工程应用具有指导意义。声波CT是一种新的无损检测技术，它是利用声波穿透被检测体获取声波接收时间，来进行计算机反演成像的技术。本文利用直射线法编制了层析成像程序，能较好地呈现被检测物体各微小单元的声波速度分布图像，从而对检测体的质量状况作出诊断评估，具有较好的应用发展前景。

The relationships between large igneous rock province, mantle plume and petroleum show that there is a low velocity-high conductive layer of mid-crust in the basin and this layer is the main source of oil and gas. Weathered granites and volcanic rocks are the best reservoir beds for hydrocarbon accumulation and the faults are the main migration pathway. It is suggested that granite and volcanic reservoirs be the future exploration targets.

通过研究花岗岩和火山岩油气藏的形成模式，指出大火成岩省、地幔柱与油气的关系表明盆地中地壳的低速－高导层可能是油气的主要来源，而花岗岩、火山岩的风化壳是油气成藏的最佳储集层，断裂则是其最主要的运移通道，花岗岩和火山岩油气藏将是未来勘探的重要目标。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失