谱性

At the same time, for the process additive and multiplicative uncertainties mostly encountered in practice, the sufficient and necessary conditions for holding the control system robust stability are analyzed, and thus, an intuitive determination method is provided based on the spectral radius criterion.

同时，对于实际中最常见的被控过程的加性和乘性不确定性，分析了控制系统保证鲁棒稳定性的充要条件，由此给出了基于谱半径判据的直观判定方法。

The paralytic shellfish poisoning toxicity levels of shellfish from alongshore sea area of the Guangxi province later years, determined with both Mouse Bioassay and HPLC.

通过对近年来广西近岸海域贝类样品的麻痹性贝毒素小白鼠生物法和高效液相色谱法检测结果的分析，表明广西近岸海域多处地区和多种生物含有麻痹性贝毒素；4-5 月及7-11月为两个毒性值的年高峰期；GTX4、GTX5和GTX3毒素成分的检出率较高等。

This conclusion can also be proved by spectrum-warping audio watermarking algorithm in MCLT domain. To discuss further deeply on why spectrum-warping technique does not have the required robustness, the studies are carried out upon the essentials of bilinear transformation. All the theoretical analysis and experiments results put the robustness of the spectrum-warping audio watermarking under questioning.

四、提出了基于量化的变换域音频水印算法中关于量化参数的选择方法量化变换系数的音频水印算法是以修改谱分量幅值为基础，算法的主要问题是如何选择量化参数以确保算法的鲁棒性和不可感知性，另外量化系数的区域选择也会影响算法的性能。

The chain structures of S SBR2305,Buna SL25 1 and E SBR1500 were analysed by FTIR,and the influences of these three SBRs on the wear resistance,heat build up,rolling resistance and wet traction of NR/SBR blend were investigated by the compression heat build up test with constant load,DMA etc..

采用傅立叶变换红外光谱分析了溶聚丁苯橡胶S SBR2 30 5、BunaSL2 5 1及乳聚丁苯橡胶E SBR15 0 0 3种SBR的链化学结构，采用定负荷压缩生热、动态力学谱等方法研究了 3种SBR对NR/SBR并用胶耐磨性、生热、滚动阻力及抗湿滑性的影响。

With the application of Partial Least Square technique and the input need of only 2-D molecular structure, it overcomes the difficulty of conformer alignment for 3D-QSAR techniques and avoids the multiple collinearity for traditional Multiple Linear Regression.

本文应用基于分子全息的QSAR技术研究了联苯以及209种氯代同系物的水溶解度、正辛醇水分配系数、总分子表面积、水活度系数和亨利常数等5种与生物累积性有关的理化性质以及气相色谱相对保留时间，建立了一批具有高度预测性的QSAR模型。

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。

Results 7 lung cancer patients were detected three marker VOCs in their breath: Benzene,Propyl benzene and Decane.

使用TEDLAR气袋收集此8例患者的呼吸气体，然后使用固相微萃取－气相色谱对呼吸气体进行分析，根据其出峰时间的不同对VOCs定性，测得患肺癌的患者的呼吸气体中含有苯、丙基苯和癸烷三种特征性气体，而炎症患者的呼吸气体中则没有出现这样的特征性气体。

Finally, we study the eventual differentiability of a C_0-semigroup associated to a waveequation with boundary dissipation.

最后，我们讨论了一类具边界耗散的线性双曲型方程生成的算子半群的最终可微性，并利用这个结果得到了方程的解具有最终正则性以及半群满足谱决定增长条件。

Some economic and practical polysaccharide-based chiral stationary phases for HPLC were prepared and applied to the enantiomeric resolution of a variety of racemates.

本论文选择高效液相色谱手性分离为研究目标，制备了一些经济、实用的多糖类手性固定相，并对多种手性化合物的拆分进行了研究。

The model considers as many factors as possible, including nonuniform distribution of photon intensity and carrier density along active region, gain spectral dispersion, spontaneous emission spectrum and facet reflectivity, and is applicable under the condition that the pulse width of injecting signal is wider than 10 picoseconds. It provides a convenient and effective theoretical platform for SOA dynamic characteristic study.

该模型考虑光子密度和载流子浓度沿有源区的非均匀分布、增益谱色散性、自发辐射噪声谱和端面反射率，适用于脉冲宽度高于10ps的信号输入的情况，为后续研究SOA动态特性提供了方便而有效的理论验证平台。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。