子阵

Let R be an arbitrary commutative ring with identity, gl the general linear lie algebra over R consisting of all n × n matricesover R and with the bracket operation = xy -yx, t the lie subalgebraof gl consisting of all n×n upper triangular (resp., strictly upper triangular ) matrices over R and d the lie subalgebra of gl consisting of all n×n diagonal matrices over R.

在第三章中，对R是交换环的情形，讨论了典型李代数的导子代数的结构问题：设R是一个含幺交换环，gl是R上一般线性李代数。t是gl的所有n阶上三角矩阵(相应地，严格上三角矩阵)构成的子代数，d是gl的所有n阶对角阵构成的李代数。

In this section we have obtained some fundamental results on closure operator of poset matroids.

在这一节我们得到了偏序集拟阵闭包算子的一些基本结论。

The new heliostat has a mirror array capable of line-tilting in order to realize a type of dynamically change optical surface which has different radius of curvature in both tangential and sagittal direction.

这是一种新型的定日镜，其中包括一个由行和列组成的镜阵，其子镜可以进行行和列方向的自适应的运动，以实时根据太阳光的入射角的变化而改变整个镜阵的曲面，实现了类似Harald先生提出的曲面。

Cross-talk between the hemispheres may be important for remembering specific events, called episodic memory, so psychologists Stephen Christman and Ruth Propper of the University of Toledo, Ohio, reasoned that lefties and righties might differ in episodic memory skills.

大脑两个半球间的相互交流可能有利于记住特别事件的阵发式记忆，因此美国俄亥俄州托莱多大学的两位心理学家Stephen Christman和Ruth Propper推测，左撇子和右撇子在阵发式记忆上应该有所不同。

During the iterations the trial step is truncated when necessary in order to keep the strict feasibility of the iteration points. It is shown that the LMTI approach and the STI approach have global convergence properties under some reasonable assumptions and will achieve local quadratic convergence rate under some even stronger conditions.

LMTI方法主要利用由有限内存BFGS公式的紧致形式获取的目标函数海色阵的近似矩阵构造信赖域问题模型并对其进行求解；而STI方法在构造的低维子空间上求信赖域子问题的解。

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。

The arc array transmitter is composed of many ceramic flexural vibrators which are arranged in an annulus. Directional radiation is realized by controlling the vibrating phase of each vibrator.

声波测井圆弧阵发射换能器由多个压电振子沿着圆周排列，通过控制各个振子的激励时间可以实现向某个方位方向的声波辐射。

The electric current and potential distribution produced by dipoles in human brain was simulated by the finite element method.

讨论用有限元法计算电流源偶极子产生的电流与电位分布，推导出计算偶极子源在各向异性导电媒质中的有限元方程，并对其进行变形，使得在各向异性导电媒质中生成的有限元刚度阵对称。

The superior properties of antenna arrays composed of unequal dipoles are discovered and the method to modify the length of each element is described.

研究了由不等长的偶极子组成的天线阵的优越性，提出了调节偶极子的长度以达到设计目的的方法。

It is shown that the M×N ChG beams in turbulent undergo three stages of evolution with increasing propagation distance,and turbulence accelerates the evolution of three stages.The turbulence results in a spreading and degradation of the maximum intensity in the far field.But β-parameter decreases with increasing beam numbers M,separate distances xd and beam parameter δ.And there exists optimal values of xd and δ,and SR of the corresponding M×N ChG beams reaches its maximum.

研究表明：在湍流大气中，双曲余弦高斯列阵光束的传输将经历三个阶段的变化，并且湍流使得光束传输经历三阶段的进程加快；湍流导致双曲余弦高斯列阵光束扩展、最大峰值光强下降，但是，β参量随光束数目M、相邻子光束间距xd和光束参量δ的增加而减少，即光束扩展受湍流的影响减小；并且，存在最佳xd和δ值使得Strehl比取得极大值。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐