查询词典 zero

Using properties of zero-divisors, regular elements and subdirectly irreducible ring , we obtain some results on the commutativity of semi-prime ring and Jacobson semi-simple ring as follows 1 Let R be a semi-prime ring ,a∈R and 2a is not zero-divisor,If R satisfies one of the conditions in this paper , then R is commutative.

在某些特殊环的交换性方面取得了进一步的结果，并得到了一些新的结论，主要有一设R 为半质环，a∈R ，且2a 为非零因子，如果R 满足论文中八个条件之一，则可以证明环R 为交换环。

In order to find a stable approximate solution of linear compact operator equation, the article introduces general theories about ill-posed problems, it bases on spectral theory of self-adjiont compact operators and the singular value decomposition for compact operators, avails singular system to give expression of the solution, and explains ill-posedness of compact operator equation roots in the property that the singular values trends to zero. Thereout, it is provided with theoretic support of building up regularization method by inducting regularization filter to weaken or filtrate the influence that the nature of the singular value being very close to zero has on the solutions stability.

为了得到线性紧算子方程稳定的近似解，介绍了不适定问题正则化的一般理论，以自伴紧算子的谱分析与紧算子奇异值分解为理论基础，利用奇异系给出了解的表达式，说明了紧算子方程不适定性的根源在于紧算子的奇异值趋于零的性质，由此通过引入正则化滤子函数来减弱或滤掉奇异值趋于零的性质对解的稳定性的影响，构造正则算子，从而提供了建立正则化方法的理论依据。

The study shows that in the radial direction the dynamic forces acting on the particle balance on the particle itself; there is not a so-called trajectory of the particle in which the composition of forces acting on the particles is zero, but there is a trajectory of the particle in which the radial slip velocity of particle is zero, the tra...

通过对固体颗粒的运动和受力分析发现固体颗粒在沉降过程中径向合力几乎处处为零，不存在所谓的径向合力为零的一个平衡轨迹面，但存在着一个径向沉降速度为零的轨迹面，这一轨迹面就是平衡轨迹面法所要寻找的；首次推导出了该轨迹面半径与固体颗粒直径、水力旋流器自身几何参数以及操作参数之间的定量表达式。

The rate of fall is dependent on the continuity of the scale function in time domain. Furthermore, it relates with the multiplicity of zero point at ω=π of the amplitude spectrum of the low pass filter. The distribution of zero points was investigated thoroughly. From the above statement, the dominant interval is deduced to be [0, 2π].

衰减性取决于尺度函数的连续性，进一步它与低通滤波器在ω＝π处零点重数有关；详细讨论了零点的分布及其重数；由零点的分布和衰减性推出尺度函数的幅值谱主导区间为[0，2π]；ω＝0处极大值性态与低通滤波器在该处性态相同。

The simulation floating zone modelwith zero temperature gradient in the middle of the hot rod is proposed to simulate thehalf part of the full floating zone convection,since the temperature gradient in the middleof a full floating zone approaches zero.

根据加热方式的不同，可以将半浮区液桥分为通常半浮区液桥模型、模拟半浮区模型以及改型半浮区模型。通常半浮区液桥模型，液桥热端材料一般选择为金属材料，使得热端温度分布均匀。液桥产生热毛细对流时，在液桥热端内侧存在较大的轴向温度梯度。而在全浮区热毛细对流中，浮区中间的轴向温度梯度在对称条件下应该接近于零。

PSO is a population-based optimization algorithm, which mimics the social behavior of animals in a flock. It makes use of individual and group memory to update each particle position allowing global and local search optimization. The objective function considered was the total weight of the structure subjected to stresses, displacements and forces constraints. The effects of the parameters were investigated as well and such combination of tuning parameters promote a better global search behavior avoiding premature convergence while rapidly converging to the optimal solution. Results showed the effectiveness of the proposed method by comparing with ANSYS Design Optimization Tool (zero-order method). The PSO with the tuning parameters makes it an ideal method for offshore wind turbines foundations optimization tasks.(2) A reliability analysis method for pile foundation bearing axial loads based PSOThe performance function of pile foundation's axially bearing capacity sometimes is nonlinear and complex, on the basis of geometric meaning of structural reliability index, an optimum model with PSO for structural reliability analysis under arbitrary random variables was established, The PSO algorithm is very efficient to solve global optimization problemsIts use in structural reliability field presents not only the advantage of its facility of implementation, but also the possibility to obtain the design point and the failure probability with a good accuracy. In addition, PSO is a zero order algorithm, for no derivative is necessary for its implementation.

本文的研究针对桩式海上风机基础结构的特点，在国内外有关研究成果的基础上对海上风机基础结构优化设计理论和可靠度方法一些相关问题进行了较为深入的研究，具体做了以下几个方面的工作：(1)基于粒子群优化的桩式海上风机基础确定性优化设计方法桩式海上风机基础的优化设计是一个复杂的、非线性约束的优化问题，针对传统的基于梯度信息的优化方法在处理非线性问题中易陷入局部最优解的问题，本文将一种耦合惩罚函数的PSO算法引入到海上风机基础结构概念设计中，PSO算法是从群体动物聚集觅食这一活动中受到启发而发展的，该算法利用个体和群体的信息共享不断改进自身的位置从而进行局部和全局最优搜索，本文中以桩和三脚架连接段直径及壁厚为设计变量，以基础总重量作为优化的目标函数，在给定的约束条件下建立了三脚架基础优化数学模型，另外本文还研究了PSO参数变化对结果的影响，协调的参数组合可以避免陷入早熟收敛而能够快速的获得全局的最优解，通过与ANSYS优化模块的计算结果比较验证了该方法的有效性，本方法为海上风机基础的确定性设计提供了一条有效的途径。

A zero - coupon bond;a zero - coupon certificate of deposit.

一张无收益的债券；一张无收益的银行存单

A zero crossing detection is synchronized which the zero crossing point of the line voltage of each of the three phases.

一个过零检测同步其中的三个阶段的每线电压过零一点。

Terminal voltage is determined by a cut-and-try solution such that the summation of reactive volt-amperes equals zero. Slip is determined from the relation that the summation of the real powers equals zero, and then frequency is obtained.

根据虚功率总合为零的原则，可求出感应发电机之端电压值，以及有效功率总合等於零的原则，求出转差率及频率来。

Can be seen, no overload is the essence of the centrifugal pump, pump shaft power curve peak, or shaft power with the increase of flow rate changes are small, relatively flat power curve that axis, so that the pump shaft power in the dead lift off to zero head (that is, from zero flow to maximum flow rate) are less than equal to the original context of the supporting motive power.

可见，无过载离心泵的实质是指，泵的轴功率曲线有峰值或轴功率随流量的增加而有较小的变化，即轴功率曲线比较平坦，使泵的轴功率在关死扬程到零扬程范围内都小于等于原动机的配套功率。

Salt is good, but if the salt becomes flat and tasteless, with what do you season it?

14：33 盐本是好的，盐若失了味，可用什么叫它再咸呢？

He reiterated that the PLA is an army of the people under the leadership of the Communist Party of China.

他重申，人民解放军是在中国共产党领导下的人民军队。