近似法

The so-called plasticity seal, the seal is the sealing surface pressure is equal Sealing than the soft material yield limit, so that Pressure sealing globe valve joint surface in close contact, use the plastic deformation of soft materials, blockage hardware uneven surface, giving rise to approximate the ideal plane, and produce equivalent soft material yield limit of the reaction and remain sealed.

所谓塑性法密封，就是密封面的密封比压等于密封副软材料的屈服极限，使结合面紧密接触，利用软材料的塑变而堵塞硬件表面的不平处，形成近似理想平面，并产生等于软材料屈服极限的反力而保持密封。

With methods of limited areas, root systems of plant individuals were limited in a specific range, providing definite spatial boundary and solid basis for calculation of water requirement needed by plant individuals. On the basis of calculation of amount of water requirement, areas needed by every species to ensure enough water requirement are as follows: Populus simonii is 80.3m〓, Ulmus macrocarpa is 35. 4m〓, Artemisia halodendron is 7. 0m〓, Salix gordejvii is 11. 2m〓. Prunus armeniaca is 15. 2m〓, and Caragana microphylla is 15. 6m〓. The corresponding rational density of plantation which can maintain soil water balance and can ensure plantation stability is 125 individuals/ha for Populus simonii, 285 individuals/ha for Ulmus macrocarpa, 625 individuals/ha for Prunus armeniaca, 625 individuals/ha for Caragana microphylla, 833 individuals/ha for Salix gordejvii, and 1428 individuals/ha for Artemisia halodendron, respectively.

运用有限面积法将植物根系限制在明确的边界内，为植物耗水量的计算提供了一个明确的空间边界范围和可靠的基础，探索性和尝试性地得出了近似野外真实状态下植物个体的耗水量，以此为基础计算得出小叶锦鸡儿、山杏、黄柳、差巴嘎蒿、榆树、杨树等树种的水分营养面积分别是15.6m〓、15.2m〓、11.2m〓、7.0m〓、35.4m〓和80.3m〓，与此对应的能够维持林地土壤水分平衡和林分稳定性的各树种人工林的合理密度为：杨树125株/公顷，榆树285株/公顷，杏树625株/公顷，小叶锦鸡儿625株/公顷，黄柳833株/公顷，差巴嘎蒿1428株/公顷。

In this paper, the following progress has been discussed:(1) the improved conjugate gradient algorithm which combines the inversion equation;(2) the formulation for velvet gene at all directions and the approximation method of Jacobian matrics based on disturbance method;(3) the model is adjusted by analyzing the influence of damp coefficient and correction factor to inversion result ;(4) the influence of damp coefficient to the resolution of inversion is studied. to some degree, we improved the problem of "barycenter ascending shift" to electric anomalous body in 3-D resistivity inversion.

本文主要讨论了以下几个方面的内容：（1）结合反演方程式改进的共轭梯度算法；（2）基于扰动法的线源Jacobi矩阵的近似计算方法及光滑系数矩阵在各个方向上的光滑因子的计算公式；（3）通过分析阻尼系数与修改量校正量对反演结果的影响，提出了利用校正系数对模型修正量进行校正；（4）较为系统的讨论了阻尼系数λ对反演分辨能力的影响，较好的改善了三维电阻率反演中的电性异常体重心的&上漂&现象。

Additionally, the approximate flattening of surface strip using lines linking midpoints on perpendicular lines between geodesic curves and the unconditional extreme value method are discussed.

提出了用测地线方程、曲面上两点间短程线来计算膜结构曲面测地线的方法，同时，采用测地线间垂线的中点连线和用无约束极值法进行空间条状曲面近似展开的分析。

Reactive flux also provide a nearly disoxygen environment which is good for the synthesis of group-5-metal sulfides and selenides.

但是第5族元素极易与氧结合而难以得到硫硒化合物，尤其是多元化合物，而反应性融盐法提供了一个近似绝氧的环境。

The formula calculating the first frequence of the bridge with the pile foundation is derived by using the Rayleigh Principle.

用Rayleigh法推导了桩基桥梁的第一自振频率的近似计算公式；在动力学效的原则下建立了桩—上—上部结构体系的等代简化模型，导出了动力等效嵌固深度l〓的计算公式，并与静力等效嵌固长度Z〓的计算公式进行对比分析，给出了静力公式的误差范围。

The inverse problem is solved using conjugate gradient method of minimization based on discrete ordinates method of radiative transfer equation.

该方法是在辐射传递方程离散坐标近似的基础上，用求目标函数极小值的共轭梯度法进行反演计算。

Based on the technology of machining the tooth profile of hobbing shaving cutter for cutting hardened gear, the approximate forming of the tooth profile on normal section is carried out by means of straight line fitting, arc fitting and hyperbola fitting.

基于硬齿面滚剃刀齿形的制造方法，分别采用直线、圆弧、双曲线拟合法对滚剃刀法截面齿形进行了近似造型。

The following are main contents studied: A finite element method for Navier-Stokes equation with ALE formulation is considered and by combined with theNewmark method of numerical intergration a pressure correction scheme is obtained for the solution of the FE formulation of N-S equation. Because the incompressibility condition can be satisfied approximately in this scheme, the interpolation functions of elements can be equalorder for the velocity field and pressure field. In the ALE formulation the fluid-solid interaction analysis became a three-field coupling problem of the fluid field, the solid field and the fluid dynamic mesh. The properties and charactiristices of this three-field coupling problem are deeply discussed.

研究的主要内容有：主容器中流体大晃动是一种强非线性问题，文中研究了求解ALE描述的粘性流体N-S方程的有限元方法，以有利于大晃动自由液面的跟踪和流体大晃动中非线性现象的描述；并结合Newmark数值积分法推出了求解ALE型N-S方程的压力修正解法，由于这种解法可以近似满足不可压条件，因此可以采用速度场和压力场等阶插值的有限元离散格式，从而较好地解决了普遍采用的不等阶插值解法中，速度场和压力场数值精度不一致、程序编制不便等的不足。

The hot helium temperature follows HTR-10's nuclear power changes slowly, and there is a large coupling between them, so the RPHHT system adopts cascade control, the minor loop is fast, and the major loop is hot helium temperature control loop whose dynamic response is slow; there is also a large coupling between main helium loop and steam-water loop, and both the main steam temperature measure signal and the heating process of the once-through steam generator are delayed, therefore, the MHFMST applies cascade control, the minor is main helium flow control loop whose dynamic response is fast, and the major is the main steam temperature control loop whose dynamic response is slow.

本文运用机理建模法，建立了HTR-10系统动态控制模型，然后进行了动态性能仿真，将堆芯用集中参数表示，冷却剂按一维流动处理；直流蒸汽发生器按二回路工质不同的相分为预热段、蒸发段和过热段，建立了三环节控制模型，得到HTR-10系统控制模型；仿真结果与数值计算结果对比表明，本文所建立的控制模型，能近似地反映HTR-10的动态特性，适合设计控制系统。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。