理论模型

An explicit formula for the enhancement factor in gas-liquid absorption with irreversible chemical reactions is presented.

提出气液化学吸收增大因子β的显函数式，并分别同膜理论、渗透理论模型以及可vanKrevelen—Hoftijzer隐函数式的数值解比较，证明显函数式相当逼近该二理论模型，同时在准确性和方便性方面都优于隐函数式。

In this paper the feasibility of taking the boundary of the theoretical model as adiabatic is firstly studied.

本文在实验研究的基础上，通过"模型分割"，并结合一维理论模型的结果，给出脉冲红外热成像无损检测三维理论模型的一种近似解法。

In order to prove the reliability, test studies have been primarily carried out in the indoor soil bin. The data of the vehicle driving state parameters under the same or different terrain are analyzed. The process curves are compared by different control schemes. The theoretical model of the optimum driving state is reliable and fuzzy control scheme is feasible. The disturbances and unknown factors of control system are analyzed. Test results prove that the half-tracked air-cushion vehicle can drive steadily under control of the computer. At the same time the sensors used to measure soil mechanics characteristics on line need to be developed. And it is the important problem to be solved in the future study. The necessary regulation and correction are put up. So the studies in this paper provide some instruction for the further research work.

为了验证本文提出的最佳工作状态及最佳垫压理论，并分析控制系统的可靠性和稳定性，本文在半履带式气垫车的模型车上，在室内土槽中进行了初步的实车性能和理论验证试验，考察了在同种和不同土壤条件下气垫车的行驶状态参数的测量数据，比较了采用不同控制方法下的过程曲线，验证了最佳工作状态的理论模型和模糊控制系统方案的可行性与可靠性，从而保证了采用自整定模糊PID控制器能够使半履带式气垫车在稳定行驶最佳工作状态下；同时通过试验研究，分析了系统中各干扰与未知因素，对控制方案进行了相应的调整和修正，为今后进一步的研究工作提供了一定的指导。

The second is to propose an "open-cell" concept and derive a model on better theoretical basis to overcome the defects of the cell theory.

用模型，以满足工程上的需要；其二是针对胞腔理论的缺点，提出"开放胞腔"的概念，建立了一个理论基础和精度更好的理论模型。

Based on the assumption that the heating floor radiation agrees with Lambert's cosine law and the outdoor human body could be equivalent to a "human cylinder", the mathematical model and formula to describe the thermal radiation from the floor to human body are established.

在基本假设和"人体柱"模型的基础上，建立采暖地板对室内人体热辐射的理论计算模型。利用该理论模型，对矩形等温地板的采暖辐射特性进行计算分析。

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。

Followed from the currency reserve structure to optimize the structure of the main factors affecting research, this paper introduces the three theoretical models: Asset Portfolio Theory, Heller—Knight Model and Dooly Model. Portfolio Theory stresses the returns and risks in arranging the structure of foreign exchange reserves.

紧接着从优化储备货币结构入手，对影响结构的几个主要因素进行了研究，并介绍了外汇储备币种结构选择的三大理论模型，即资产组合理论、海勒——奈特模型和杜利模型。

In the paper, theoretic transfer heat model of HHCHP is established. After comparing experimental value and estimative value, we deduce that theoretic transfer heat model accords with actual condition, so we can estimate the heat performance of HHCHP by theoretic calculation formula.

同时建立了蜂窝热管平板式太阳能热水器的理论传热模型，通过对实验值和理论值的比较，得出进行简化后的理论模型在一般情况下与实际的情况是符合的，因此可以用理论计算公式对蜂窝热管平板式太阳能热水器的热性能进行估算。

Based on Euler equation, a mathematical formula of this method is derived and a algorithm for calculating parameters of multiple sources is provided. Model studies show that the method can locate or outline multiple sources with remarkable accuracy in two or three dimension.

推导出了组合模型二维和三维欧拉反演方法的理论计算公式，提出了相关的计算步骤，并通过理论模型演算证实了该方法对于组合模型反演的正确性和可靠性。

2Theory of pulse combustion was analyzed and its mechanism were discussed with planewave transferring theory in the thesis.Models of pulse combustor were reviewed and analyzed.Theone-dimensional unsteady nonlinear model of pulse combustor was simplified with lineal method.The phase relation between pulse pressure and combustion heat discharge which may prompt ordamp pulse combustion process were discussed.

对脉动燃烧理论进行了分析探讨，从平面波的传递理论出发，分析了脉动燃烧的机理；在归纳综合现有的脉动燃烧器理论模型的基础上，采用线性化分析方法，对一维非线性脉动燃烧器理论模型进行了简化，并定性分析了脉动压力与燃烧放热之间的相位关系对脉动燃烧过程的激励和阻尼作用。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。