基本域

In this paper, we summarize the foundations of Algebraic function fields, algebraic curves over finite fields and algebraic geometry codes, then we focus on the dimensions of codes on the quotient of the hermitian curves, by using the theory of weierstrass semigroup and the idea of Ho...

我们在系统地总结了代数函数域，有限域上的代数曲线和代数几何码的基本知识的基础上，利用Weierstrass子半群理论，使用Homma和Kim的方法，讨论了Hermite曲线商域上码的维数问题，得到的主要结果如下： 1。

Quadratic algebraic function fields are studied here.Fundamental units forseveral types of such fields are determined explicitly.

本文研究了二次代数函数域，明显决定了几类实二次函数域的基本单位，决定了多类二次函数域的理想类数的下界，给出了类。。。

This thesis has generalized the characteristics of displacement model's confidence region, inferenced the shapes of plane and space displacement confidence region, determined calculating formula of confidence region.

文中对位移模型置信域的基本特征进行了归纳、推导，确定了平面和空间位移置信域形状，给出了确定置信域的计算式。

In this paper, by using the kinematic measure for a segment of fixed length within a special convex domain, we obtain the Buffon probability formula of grid whose basic regional are two different convex domains, and its outreach to various convex domain cases.

本文通过利用凸域内定长线段的运动测度，给出了以两个不同凸域的并为基本区域的网格的Buffon概率公式，并将其推广到多个不同凸域的情形。

Then, for the first time, a finite element model of the cylindrical shell surface was bring forward and set up.

首次提出和建立了柱体坐标系下的曲面柱壳单元有限元模型，以及在柱坐标系下的边界元法基本方程和柱坐标系下无限域与半无限域基本解。

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

Based on Wilson\'s lemma on evenly distributed differences, elementary number theory and fundamental theory of finite field, the finite field construction for strict optimal OOCs is proposed and the basic idea of this construction is investigated. The main steps and flow chart of assistance design by computer are obtained.

3基于Wilson均匀分布差引理、初等数论及有限域的基本理论，提出一种严格最佳光正交码的有限域构造法，对该构造法的基本设计思想进行深入的理论分析，得到该构造法计算机辅助设计的主要步骤及流程。

Basic knowledge of digital watermarking such as background, fundamental theory, characteristics, algorithm evaluating is introduced in this thesis.

本文简介了数字水印背景、基本原理、特征、算法评测等基本知识，介绍了目前主流数字水印算法，给出了DCT域和DWT域两种数字盲水印算法。

It includes the basic structural theory of groups; groups'actions on sets and the applications of these actions; the basic structures of rings; the properties of uniquely factorized domains; the Chinese Remainder; the extensions of fields; finite fields with applications; the Galois theory with applications.

主要内容包括群的基本结构理论、群在集合上的作用及其应用、环的基本结构和因子分解理论、中国剩余定理、域的扩张理论、有限域及其应用、Galois 理论及其应用。

Active attack cryptanalysis based and fully scalable FGS encryption algorithm Aimed to the weakness of the current selective encryption algorithms in the sense of cryptanalysis, we design a active spacial—temporal correlation attack scheme and propose a both encryption strategies on base-layer and enhancement-layer. Not only the general FGS stream encryption is dealt with but also the case of FGST (fine granularity sealable temporal) is also well addressed.

2基于主动攻击安全的充分可扩展FGS加密算法针对目前压缩视频流加密算法所经常采用的选择加密方法，通过进行主动时域、空域相关性攻击，指出该类算法存在的问题，包括对于FGS基本层单独加密的安全分析，然后设计实现了基本层和增强层同时加密的安全策略，为保证FGS充分可扩展功能，算法同时还支持细粒度时域可扩展编码FGST(fine granularity scalable temporal)的情况。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。