近似计算

Kinds of Schiff base derivatives of 2-N-benzylidene Furanmethanamine have been designed. The Net Charges of main atoms, bond lengths, bond angles, dihedral angles, IR have been calculated by means of HyperChem6. 0 program. 36 kinds of Schiff base derivatives of benzylidene adenine have been designed. Also the net charges of main atoms, bond lengths, bond angles, dihedral angles, IR, the energy gap △E between HOMO and LUMO and the nonlinear second-order polarizability β have been calculated by means of HyperChem6. 0 program. The calculated results indicated that the nonlinear second-order polarizability β were up in accordance with the △E down.

设计了腺嘌呤缩苯甲醛36种衍生物，计算了这些分子的气相几何，腺嘌呤缩苯甲醛中各原子的电荷分布，最高占有轨道HOMO和最低未占有轨道LUMO的能量以及它们之间的能量差△E，同时还计算了这些分子的二阶非线性极化率β，我们发现腺嘌呤缩苯甲醛的二阶非线性光学系数与△E有近似一致的变化关系，随着△E的减小，二阶非线性光学系数有增大的趋势。

By time-varying filtering, we realize the signal selectivity and interference suppression, especially for the signals with time-varying power spectrum. It is shown herein that conventional eigenstructure based methods are lower dimensional special case of the time-frequency subspace fitting method. The closed-form array response estimation algorithms for blind source separation in wireless communication is also developed in the dissertation by exploiting the data structure of second-order statistics of the array output in the presence of multipath. The proposed method achieves array response estimation with little constraint on signal property and propagation environment such as scatters or angular spread. Moreover, the array utilized here can be of arbitrary geometry and even uncalibrated. Since the closed-form solution is obtained, no misconvergency may occur and large amount of computation can be saved. The equivalent feed model and corresponding optimization designation are proposed to realize the downlink multi-user selective transmission. By coherent and non-coherent superposition of the electromagnetical field, multiple beams can be formed using a single array, so that each co-channel user signal is transmitted in each beam and will not interfered with each other. The proposed system scheme implements the digital beamforming and the channel allocation in the base band, therefore is suitable for the utilization of the radio software technology. The feasibility and effectiveness of the proposed model are proved by the RF experiment.

在窄带条件下，GSC－SSF方法还可以提高阵列的虚拟孔径，从而提高估计的性能；可以证明，Cyclic DOA 和SC-SSF方法可看作该方法的特例或近似； 3、提出了二维GSC－SSF方法和宽带谱相关DOA矩阵方法，利用信号的循环平稳特性解决了宽带条件下二维 DOA 估计问题，并具有阵元数少、计算量较小的特点； 4、提出了时频子空间拟合和宽带时频DOA估计算法，将联合时频分析的理论和方法引入到阵列信号的空间谱估计研究中，利用时变滤波实现信号选择性测向和干扰抑制，特别适合于谱时变信号；可以证明传统特征结构法可看作是时频子空间拟合方法的特例； 5、提出了多用户环境下阵列响应的估计方法——CARE方法，该方法对信号结构和传播参数（主要是散射源分布与角度散布）的约束较少，适用于各种几何结构的阵列甚至未校准的阵列，能够直接得到阵列响应的闭式解，因此计算量小、稳健性好，不存在收敛问题； 6、提出了针对多用户下行选择性发送的阵列等效激励模型、优化设计方法及其系统实现方案，通过空间场的相干叠加与非相干叠加使得单一阵列能够形成多个波束，并保证各波束内的用户信号各不相同且相互干扰最小；其系统方案具有在基带实现数字波束成形、信道分配并便于软件无线电实现的特点，其有效性已得到外场实测数据的证实。

Traditionally the natural frequencies of finned tubes are calculated by some approximate methods, however, which have an influence on the precision.

对于翅片管的固有频率计算一直采用近似的方法，影响了计算精度和使用。

Based on calculating the first-order corrections to the energy from relativistic and mass-polarization effects, we estimate the higher-order relativistic contribution and QED correction to the energy under a hydrogenic approximation. The transition energies, wavelengths and oscillator strengths for the 1s23s-1s2np transitions of this ion are calculated.

在计算相对论效应和质量极化效应对体系能量的一级修正的基础上，通过引入价电子的有效核电荷，在类氢近似下，估算了对能量的高阶相对论修正和QED修正，计算了该离子1s23s-1s2np的跃迁能，波长和在三种规范下的振子强度。

Z2Bn z$e0A0 Meshless method is a new numerical computation method that is developed rapidly in recent years. Without element mesh and based on the dispersed nodes to form approximate interpolative function dynamically, meshless method has distinct difference with traditional finite element method. Meshless method conquers the problems caused by mesh generation, mesh aberration and mesh move. With provides a new effective means to engineering problem, meshless method obtain highly recognition in international compute mechanics domain and engineering field.

6L！y6K1Q6h0k0 无网格方法是近年来迅速发展起来的一类新型数值计算方法，它们不借助单元网格而是基于离散结点动态构造近似插值函数，与传统的有限元方法有着显著的区别，克服了网格生成、网格畸变和网格移动引起的问题并为工程问题提供了一种新的有效分析方法，受到了国际计算力学界和工程界的高度重视。

By deducing the calculation formula of luminaire efficiency and illuminance on working face, and analyzing a case of lighting, the paper can help lighting designers design efficient and excellent lumination by aptly using luminous intensity distribution curve.

结果 推导出利用配光曲线计算灯具效率和工作面照度的近似公式。结论灯具的配光曲线能够反映出灯具的许多重要特性，配光曲线在照明计算中提供又一便捷工具，正确利用灯具的配光曲线，对建筑照明设计具有重要的指导作用。

In aim at the complicity and high-dimensional state-space for the controlled system, it simplifies the calculation of geometric polytope by optimize with ellipsoidal approximate techniques, and the robust control effectiveness near to the optimal.

本论文所提示的基于几何理论的约束非线性控制算法是建立在最大输出允许集合的基础上，运用状态空间的有界子集表达鲁棒时优离散时间控制问题的价值函数，通过逆序计算该价值函数的水平集合，求得其所需的控制量，针对被控系统的复杂性及高维状态空间问题，运用椭球近似技术予以优化，使得几何多面体的计算得以简化，且鲁棒控制效果接近最优。

The new expansions have advantage of being translationally invariant.

我们采用Lorentz规范，对三个常见的多点函数真空平均值作了展开，得到的展开式具有平移不变性，我们利用这些展开式，计算了胶子和夸克在链近似下的完全传播子，而包括非微扰效应的夸克完全传播子在固定点规范下是计算不出来的。

On the basis of analyzing the blasting characteristics of rock at bench slope in open-air blasting,this paper puts forward a calculation model of front-row burden,and deduces an approximate formula for calculation of reasonable front-row burden length for open-bench blasting ,which can be used as reference for blasting design.

在分析露天台阶爆破时台阶坡面岩石爆破特点的基础上，提出了台阶爆破前排抵抗线长度计算模型，从而推导出计算合理前排抵抗线长度的近似公式，可供爆破设计时参考。

On the basis of analyzing the blastingcharacteristics of rock at bench top in multi-row bench blasting, this paper puts forward a calculation model, deducces an approximate formula for calcualtion of reasonable stem length for multi-row bench blasting, which can be as reference for blasting design.

在分析台阶多排孔爆破时台阶顶部岩石爆破特点的基础上，提出了多排孔台阶爆破堵塞长度计算模型，从而推导出计算合理堵塞长度的近似公式，可供爆破设计时参考。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。