查询词典 depth of field

A new prestack depth migration method that is based on wave field continuation has been developed by combining physical model of plane wave synthesizing with Fourier finite difference operator for wave field continuation.

本文将平面波合成的物理模型与傅里叶有限差分波场延拓算子相结合，提出了一种新的基于波场延拓的叠前深度偏移方法。

Based on the well-know Pennes'' bioheat equation,we calculated theoretically temperature field of HIFU-induced BFR in tissue,and measured spatial temperature rise in BFR induced by HIFU in freshly excised cow liver at constant acoustic intensity and exposure time, and studied the effects of the physical parameters of focused ultrasound transducer such as frequency,outer radius and curvature radius,focal depth, and acoustic intensity and exposure time on the temperature field of HIFU-induced BFR.

采用生物热传导方程理论计算了HIFU生物学焦域温度场，采用微型热电偶探针测量了HIFU辐照离体牛肝时靶组织温度分布；研究了聚焦超声换能器的物理参数、辐照深度和治疗剂量对HIFU生物学焦域温度场的影响；研究了HIFU在牛肝组织中的传播衰减。

In order to avoid the repetition, we find a group of coefficients that are generated with field and its gradient data. To establish explicit linear relation between structural index based on the linear relation, depth is calculated when calculated parameters are given without touching the field data. Accordingly, it can avoid the repetition of Euler's equation calculation and greatly reduce the works load as well as enhance efficiency.

为了避免这种重复，这里找到了一组系数，该系数与场值及其梯度值有关，并直接建立起场源位置与构造指数N简单的对应关系，从而把解欧拉方程的最小二乘问题转化成了解线性方程的问题，避免了解欧拉方程组时的重复计算，大大地减少了计算工作量，有效地提高了工作效率。

The numerical calculation shows that the space distibution of the electromagnetic field in each sub-micro-layer changes with the varing transmission depth in the relief grating, the space distribution in each sub-micro-layer is uniformer than that in isotropic grating and the optical parameters of the anisotropic relief grating and the incident beam have a large impact on the space distribution of the electromagnetic field in relief grating and so on.

数值计算表明，光波场光强的空间分布随透射深度的变化而变化，各向异性介质光栅体内光波场的空间分布相对各向同性介质要均匀，光栅材料的性质参数和光束的入射参数对光波场光强的空间分布有较大的影响等。

This study takes the reservoir of the Kela 2 gas field of the Tariam basin, the western China, as an example for understanding the relationship between the porosity and permeability and autogenetic minerals and textures of the clastic rocks on the vertical depth scale. The secondary pores are essential reservoir space in this gas field, moreover, their origin is closely related to dissolution of the frame grain of plagioclase and the cements of calcite.

本文以克拉2气田储层为研究对象，探讨了该区纵向深度上孔隙度、渗透率与矿物组合、结构上的变化，发现次生孔隙是本区储层的重要储集空间，并且与长石骨架颗粒和方解石胶结物的溶蚀密切相关。

The maximum field is situated in main junction, maximum field increasers with the increase of ring spacing and decreases with the increase of lateral diffusible depth.

环右侧最大电场也出现在结处，随着环间距和横向扩散深度的增加，最大电场均减小。

The purpose of the primary field of study is to give the student an in-depth specialisation and expertise in a selected field.

该领域的研究的主要目的是让学生深入的专门知识和在选定的领域。

It focuses on journalists themselves and attempts to understand the interactive relationship of TV news workers, colleagues and managers though field study and in-depth interviews. Finally, I use grounded theory to analyze field information, concretizing the research subject and goals, with discussions of the model of news production in pack journalism.

本研究以「一窝蜂新闻学」为根基，并以以「记者一窝蜂动作」为经，「与同业、决策者的互动关系」为纬，并援引Bourdieu新闻场域理论与Giddens的结构行动论，解析造成一窝蜂新闻产制与新闻同质化的内、外在因素。

This paper makes the fitting analysis of the field test data according to the hyperbolic model established by the interface spring theory,and simulates the experiment of bolt upraising by means of the finite element method.After the comparison of the calculated results with the field test results,the paper draws the main conclusion that good fitting effect can be obtained when the hyperbolic model is adopted in fitting the relationship between axial force and depth.The interfacial shearing stiffness will so...

文章按照界面弹簧理论所建立的双曲线模型，对试验实测数据进行了拟合分析，并采用有限元法对锚杆上拔试验进行了模拟，对比计算结果和实测结果得出的主要结论为：采用双曲线模型拟合锚固轴力随深度变化的曲线，可以取得良好的拟合效果；在逐级加载的条件下，界面的剪切刚度呈软化的趋势；在锚固界面没有发生较大滑移的情况下，计算位移和实测位移比较接近。

For strengthening the supervision and management of temperature field of concrete and the temperature difference between inner face and surface,the heat sensors are buried in typical sections of concrete in different part and depth in order to test the temperature of each typical section and draw the temperature field graph and temperature drop graph which can guide the task of temperature lowering and thermal retardation.

为加强对浇筑体温度场与内表温差的监测与管理，通过采用在混凝土不同部位及深度的典型截面埋设热传感器，测试各典型截面的温度，及时绘出温度场、温降曲线图，一方面可指导降温、保温工作的进行；另一方面可通过测温总结出大体积混凝土的温度变化和分布规律，为以后在铁路客运专线桥梁工程的施工中防止大体积混凝土出现有害裂缝提供有价值的参考数据和方案。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。