最小密度

School of Electronic and Information Engineering,Dalian University of Technology,Dalian,Liaoning 116024,ChinaStable processes can better model the impulsive random signals and noises in physical observation.This paper briefly describes its spectral representation,proposes a new different spectral density from power spectrum density of second order processes,thus can get a new concept of stable white noise based on covariation spectrum,and a method of identification of nonlinear PAR system based on least p-norm.

描述了稳定分布的谱表示，提出了共变谱密度的概念，得到一种基于自共变序列与共变谱的稳定分布白噪声与有色噪声的概念及其判断标准，对传统意义上的白噪声进行了广义化，依据多项式自回归系统模型，对基于稳定白噪声输入的系统输出非线性稳定有色噪声建立其非线性PAR模型，提出基于最小P范数的EIRLP算法对非线性PAR系统进行辨识。

Experiment results indicated that the anodic processes of copper, cupronickel-welded joint and brass-welded joint were similar in artificial seawater. At the same electrode potential, the corrosion current of cupronickel was the lowest and the corrosion resistance was the best, which is consistent with the EIS result.

结果表明：紫铜、白铜焊缝和黄铜焊缝在人工海水中的阳极过程类似，相同电位下，白铜焊缝的电流密度最小，耐蚀性最佳，与阻抗测试结果一致。

By Minimum Directional Derivative analyzing,it was also found that the FTEs were of the quasi-2D structure,the direction of the current was almost parallel to the plasma flows and the axis of the flux tubes.

应用最小方向微分法，发现这些FTE事件具有准二维结构，即为圆柱形结构，其通量管轴线方向与管内电流方向及粒子运动方向基本平行。关键词：电流密度；磁通量管；磁层顶

Since most of the large molecules containing phosphorus element have double bonds, it is necessary to consider the special structures of double bonds in order to deal with these large systems more accurately. So, based on density functional theory and electronegativity equalization principle, applying a general atom-bond electronegativity equalization method , using separated program, through regression and least-squares optimization , the parameters of atoms and bonds in molecules are determined . By these parameters , the charge distributions and the energy of some molecules containing phosphorus element, especial the fragment of DNA, RNA, are calculated . The results are quite good.

由于这些含磷生物大分子体系都含有双键，为了明确的处理双键，进而更准确的解释带有双键和共轭双键的含磷生物大分子结构与性质的关系，我们以密度泛函理论~([1-4])和电负性均衡原理~([5-9])为基础，应用和开发原子-键电负性均衡方法中的σπ模型，利用最小二乘法，拟合确定了一些分子（含碳、氮、氧、氢以及磷等原子）的各种类型原子及化学键区域的参数，并利用上述参数计算了一些多聚核苷酸的电荷分布以及分子的总能量，进行了讨论，得到的结果可以和从头算相媲美。

On the basis of the power spectra of earthquake records, the parameters of the power spectral density function of the twice filtered Gaussian white noise process are determined by adopting the least squares procedure of a nonlinear function.

根据地震记录的功率谱，采用非线性函数的最小二乘法，确定了两次过滤Gauss白噪声过程的功率谱密度函数的参数。

For the minimum dry density test of sand, test devices are improved to simplify the procedures and the test steps are adjusted to reduce the measurement error. The reverse graduated cylinder method and the tilting graduated cylinder method are recommended as the best methods for minimum dry density test and for leveling sand surface respectively. The optimum sampling quantity and the times of reversing graduated cylinder are studied.

对最小干密度试验，改进了试验装置以简化操作手续；调整了试验步骤以减小测量误差；推荐只使用量筒倒转法测量，用量筒倾斜法整平砂面；研究了最佳取样量和量筒倒转次数。

In our study, at180W the inflexion of the minimum resistivity point is not found which might becontributed to the use of our ultra-density target.

试验中未出现180W处电阻率最小的拐点，与作者采用了超高密度的溅射靶材有关。

Therefore it ensures the availability of the abrasion-ablation model and the insensibility of the only adjustable parameter α.

总之为了提取可靠的弹核核子密度分布，必须挑选受核反应过程干扰最小的弹核碎片，以保证abrasion-ablation模型的适用性以及唯一可调参数α值的不灵敏性。

For the first time,Curve equations of flight profiles have been developed using differ-ential and integral calculus method and curve equation of three kinds of flights were giv-en:equal cross-section distribution flights,equal angular distribution flightsand equal horizontal diameter distribution flights.

提出更全面的评价抄板撒落物料特性的数学模型，完成了计算抄板撒落物料特性的计算机程序，绘制了抄板撒落物料的特性曲线，并且以单元撒落密度偏差总和最小为目标，对抄板的结构参数进行优化设计。

In order to avoid the local minimum and reduce redundant computation, the traditional MIL algorithm-diverse density was improved.

为了避免局部最小值和减少冗余计算量，对传统的多示例学习算法－多样密度算法进行了改进。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。