查询词典 element of best approximation

The stopband error of prototype filter is used to be the objective function for optimization. Instead of the method of least square approximation, this paper introduce the method of best uniformity approximation.

选择低通原型滤波器最大阻带衰减为优化的目标函数，通常的优化目标函数选用最小平方逼近的方法，本文提出了使用最佳一致逼近的方法。

By analysing the compute result of the quadratic approximation formula, we educe the conclusion that 3 is the best rank code for the quadratic approximation formula.

通过对最小二乘拟合公式实际计算结果的分析，得出了"拟合公式阶数取3为最佳"的结论。

In the second chapter, elementary theories and ideas of one step forming inverse approach were described and warped modification method, implemented by Cook, was introduced into one step forming simulation and based on idea of surface spreading; new quadrilateral element modification arithmetic was put forward. By spreading warped quadrilateral onto plane in local coordinate system, a plane quadrilateral element whose shape and area were equal to original warped quadrilateral element was gotten and internal force vectors of four nodes and stiffness matrix of elements were improved to increase precision of simulations on this plane element.

第二章从一步成形逆有限元法的基本理论和思想出发，将Cook基于弹性理论的四边形单元的翘曲修正算法引入基于塑性的一步成形，并且基于曲面展开的思想，本文提出一种新的四节点单元翘曲修正方案，通过把翘曲的单元展开的方法在局部参考系中得到一个与实际翘曲单元的形状与面积非常接近的平面单元，在该平面单元中进行单元刚度及内力向量的计算，进一步改善模拟结果的精度。

Firstly it describes the development ,basic principle and application and propagation characteristic of mobile channel , then investigates the system structure of DAB transmitter and receiver separately and the key technology of realization of the digital audio broadcast system.And then discusses the system component of FFT －the demodulation module of OFDM .The 409- points FFT module employs a radix-4 decimation-in-frequency algorithm, includes arithmetic element , read and write address element ,twiddle factor element and control element , is realized by FPGA. In the end , the result is verified in the matlab .

首先概述了OFDM的发展、基本原理和应用以及移动信道的传播特性，接着分别研究了数字音频广播接收机和发射机的系统结构，以及数字音频广播系统实现的关键技术，然后详细论述了OFDM解调模块FFT的系统结构，主要研究了4096点FFT采用基－4按频率抽取实现的算法，整个FFT模块包括了运算单元、读写地址单元、旋转因子单元以及控制单元，并且在FPGA中进行了硬件实现，并在matlab环境下对结果进行了验证。

The invention also discloses a system of searching path, the said system is composed of an establishing element of auxiliary chart and arithmetic element. The said establishing element of auxiliary chart is used to establish an auxiliary chart for reflecting all the usable link resource in network and established path pair of minimum cost. The said arithmetic element is used to search a path for satisfying the reliability constraint in the auxiliary chart after receiving the service connection request.

本发明还公开了一种寻找路径的系统，该系统包括辅助图建立单元和运算单元：所述辅助图建立单元用于建立反映了网络中所有能够使用链路资源及能够建立的最小代价路径对的辅助图；所述运算单元用于在收到业务连接请求后，在所述辅助图建立单元建立的辅助图中寻找到满足可靠度约束的路径。

The results indicate that the effect of alloying elements V and Cr on mechanical properties at room-temperature, creep behavior and microstructures are similar. With increasing contents of V and Cr, their mechanical properties produce little change, the creep resistant property decreases and microstructure grows, which is mainly due to their characteristics of β-stability element and smaller atomic radius compared with Ti. On the contrary, the effects of V and Cr on the thermal stability are quite different. With increasing V content or decreasing Cr content the thermal stability for the alloy becomes better, which may be due to the different solution characteristics of V and Cr element in titanium alloy that V belongs to isomorphous β-stability element and Cr belongs to eutectoid β-stability element.

结果表明：合金元素V和Cr对Ti40合金室温力学性能、蠕变行为和组织的影响具有相似性，即随V和Cr含量的降低，合金室温综合力学性能变化不明显、抗蠕变能力减弱、组织粗化：这与V和Cr同属于β稳定元素、且原子半径都小于Ti原子有关；而V和Cr对于热稳定性能的影响则完全相反，V含量的增加或Cr含量的降低含金热稳定性能优化，其主要原因可能与V属于同品型β稳定元素而Cr属于共析型β稳定元素有关。

The blood pressure of.1 of pathology physiology mechanism that SAS causes CVD breathes time-out to be able to bring about airframe in elevatory Morpheus anoxic, sympathetic is excessive and excited, element of serous catechu phenolic amine, kidney and hemal endodermis element are elevatory, bring about hemal easy of hemal convulsion; to shrink the function is disorder, can make blood-vessel flowing flesh happening reframes and fleshy, systemic blood-vessel obstruction adds element of the kidney when; is chronic and anoxic, system of hemal and nervous element is activationed, bring about blood pressure to lift. Obstruction of way of energy of life of patient of OSAS of disease of blood of 1.2 low oxygen increases, cause air current to interrupt, breath pauses, at the same time airframe gets used to low oxygen environment gradually, breathing centre drops to low oxygen and sensitivity of disease of blood of tall carbonic acid, breath suspends a frequency increasing, farther aggravating airframe is anoxic. 1.3 heads are self-adjusting the function drops normal person changes quickly in systematic circulation blood pressure when, the head can be passed adjust independently functional generation protects effect, make change of cerebral blood flow not big.

SAS诱发CVD的病理生理机制。1血压升高睡眠中呼吸暂停可导致机体缺氧，交感神经过度兴奋，血浆儿茶酚胺、肾素以及血管内皮素升高，导致血管痉挛；血管舒缩功能紊乱，可使血管平滑肌发生重构和肥厚，全身血管阻力增加；慢性缺氧时肾素—血管紧张素系统被激活，导致血压升高。1.2低氧血症OSAS患者气道阻力增加，造成气流中断、呼吸暂停，同时机体逐渐适应低氧环境，呼吸中枢对低氧和高碳酸血症敏感性下降，呼吸暂停次数增加，进一步加重机体缺氧。1.3脑自动调节功能下降正常人在体循环血压快速变化时，脑可通过自主调节功能产生保护效应，使脑血流量变化不大。

Based on the shell element degraded from the continuous body, concrete and configured steels are modeled by the layered shell element, and the vertical steels burdened with added loads are completed by the combined shell element. Then, with the smeared crack model, associated flow rule and Madrid hardening model, the material nonlinearity of the concrete is depicted. The stiffness matrix of nonlinear thin-walled shell element is deduced. As for RC multi-T girders subjected to transverse loads, the properties, such as crack expanding and steel yielding, are studied.

基于实体退化壳单元理论，采用分层单元模拟了混凝土和构造钢筋，采用组合单元模拟了受力纵筋；并利用弥散裂缝模型、关联流动法则和Madrid强化准则等来描述了混凝土的材料非线性，推导了非线性薄壁壳单元的统一单元模式，研究了横向荷载作用下RC多T梁上部结构的裂缝发展和钢筋屈服等性能。

Ii The parallel computing of spectral element methods by element-by-element strategy is analyzed deeply, and we design a high-performance spectral element parallel software package named PSES.

ii将有限元方法中的逐元素策略应用于谱元素方法的并行计算，在PC机群上设计实现了并行应用软件PSES。

The model consists of an improved Bingham element(a frictional element in parallel with a nonlinear dashpot) in series with a nonlinear spring element and a mass element.

该力学模型由改进的Bingham单元(库仑摩擦单元与非线性粘滞单元并联)、非线性弹簧单元和质量单元串联而成。

A historical region of southwest France between the Pyrenees and the Garonne River. The duchy of Aquitaine was joined with France after the marriage of Eleanor of Aquitaine to King Louis VII in1137, but its possession was disputed after her subsequent marriage to Henry II of England.

阿基坦法国西南部一个历史地区，位于比利牛斯山和加隆河之间，在1137年阿基坦的埃莉诺与国王路易斯七世结婚之后阿基坦公国加入法国，但当她再嫁英国亨利二世后，其归属权便受到争议

There are moments when I look at the smiling , happy faces of my expectant staff and wonder how they will cope when confronted by an outraged housemaster along with an unrepentant and recalcitrant bleached blond teenager in 18 years ' time .

有时候，我看着那些满怀期待的员工微笑，幸福的脸，想着当他们遇到一位愤怒的宿舍管理员和一位不知悔改，叛逆，而且将头发染成白色的18岁少年时，他们会如何处理。