值分布
- 与 值分布 相关的网络例句 [注:此内容来源于网络,仅供参考]
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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。
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The main work can be summed up as follows: Firstly, we studied the thermal-field properties of VCSELs, and analyzed the influences of current spreading, material parameters and operating conditions on the temperature distributions. Secondly, we began with the electrode voltage and calculated the equipotential s distributions, compared the distributions of voltages and current densities in different depths of VCSELs, and then studied the influences of the oxide-confining region with different position or thickness, and the different sizes of the gain-guided aperture and emitting window on the distributions of the injected current density, carrier concentration and temperature in the active region. Thirdly, we realized the coupling of electricity, optical and thermal-fields, worked out the threshold voltage, calculated the distributions of the injected current density, carrier concentration and temperature under different offset voltages, and analyzed the impacts of temperature profile and carrier density on the refractive index, Fermi levels and optical-field. Finally, we gave the equipotential line distributions with considering N-DBR and double oxidized-confining regions, and analyzed theinfluences of N-DBR and double oxide-confining regions on the distributions of the current density, carrier concentration, temperature and optical-field.
具体工作可以概括如下:首先,研究了VCSEL的热场特性,分析了电流扩展,材料参数和工作条件对于温度分布的影响;其次,从电极电压入手,计算出激光器中的等势线分布,并对不同深度处的电压和电流分布进行比较,研究了高阻区的不同位置和不同厚度、限制层和出射窗口半径的大小对电流密度、载流子浓度和温度分布的影响;再次,实现了电、光、热耦合,求出了阈值电压,计算了不同偏置电压下的电流密度分布、载流子浓度分布和热场分布,分析了温度和载流子浓度变化对折射率、费米能级和光场的影响;最后,给出了考虑N-DBR和双氧化限制层时激光器中的等势线分布,分析了N-DBR和双氧化限制层对VCSEL电流密度、载流子浓度、温度和光场分布的影响。
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Based on expansion of ODF in series of Generalized Spherical Harmonics by Bunge, we design programming in Orientation Distribution Function for polycrystal which contained five thousands crystals based on increment arithmetic of Voronoi. Geometrical data information, ODF of every crystal in polycrysal are imported to Open Graphics Library to draw, that means we implement visualization of ODF for every crystal in polycrystal.
主要针对具有立方结构的多晶体材料,采用Bunge级数展开法模型计算取向分布函数的理论模型,利用C语言在VC++环境下对ODF值进行了计算,并以Voronoi增量算法为基础生成包含有5000个晶粒的多晶体材料各晶粒的几何数据信息,与计算得到的ODF值一起导入OpenGL进行可视化处理,直观显示了多晶体材料中ODF值在各晶粒内的分布。
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Studied present measuring methods" advantages and disadvantages, and presented the necessity and importance of researching propellant transient heat transfer.2.according to 130 and aeronautic 90 rocket projectiles" structure, analysed and acquired physical and mathematical models for propellant transient heat transfer, also designed propellant temperature field simulation units for test.3.acquired discrete transient heat balance equation and temperature calculation program, and gave contrasting curves between experimental temperature values and program calculating temperature values as well as maximum errors and average square root errors between them.4.by programs based on the first class boundary condition, worked out temperature distribution in propellant temperature field simulation units at different time, analysed temperature field distribution law and main elements affecting heat transfer, acquired propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.5.established transient heat transfer mathematical model and temperature calculation program for the third class boundary condition, drew contrasting curves between temperature experimental values and calculation values and gave maximum errors and average square root errors between them, got temperature distribution in the simulation unit at different time and main elements affecting heat conduction, figured out propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.
分析了现有测试方法的优缺点,提出了研究推进剂瞬态导热的必要性和重要性。 2。根据130和航90两种火箭弹的结构,分析得到了推进剂传热的物理模型和数学模型,设计了推进剂温度场模拟实验装置。 3。得到了离散形式的瞬态热平衡方程和温度场计算程序,给出了实验温度与程序计算温度值的对比曲线及其最大偏差与均方差。 4。利用程序求出了第一类边界条件下、不同时刻推进剂温度场模拟装置中的温度分布,分析了温度场的分布规律和影响传热的主要因素,求出了推进剂质量加权平均温度和最大肉厚1/2处的温度时间曲线并给出了两者之间的最大偏差与均方差。 5。建立了第三类边界条件下的瞬态导热数学模型和温度计算程序,求出了温度实测值与计算值的对比曲线并给出了两者之间的最大偏差与均方差,得到了不同时刻温度场模拟装置的温度分布与影响导热的主要因素,求出了推进剂质量加权平均温度和最大肉厚1/2处温度及两者之间的最大偏差与均方差,讨论并确定了能代表130和航90推进剂温度的特征点的位置。
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The tensile strength and the elastic modulus were assumed to obey Weibull and logarithmic normal distribution and the other mechanical parameters were taken as constant values in the simulations of three-graded-concrete supported beam. The random aggregate random parameters model was established, which is very close to the actual structure. The results show that the nonlinear behavior of higher homogeneous specimen appears later obviously; the influence of random distribution of elastic modulus on the mechanical character is very little in linear range, while great in nonlinear range; random distribution of tensile strength affects the strength and the damage threshold of concrete obviously.
对三级配混凝土简支梁进行数值模拟时,假定各相材料的抗拉强度和弹性模量服从Weibull、对数正态两种随机分布,其他力学参数取定值,生成和实际结构比较接近的随机骨料随机参数模型,数值模拟结果表明材料均质度较高的试件出现非线性行为的时间要明显滞后于均质度较低的试件;弹性模量分布的随机性对材料线弹性段力学性能的影响极小,而对非线性区域的影响较大;材料强度分布的随机性对混凝土的强度和损伤阈值有较大的影响。
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Initially the following measures are taken for association of the angle positions to physical reflectors, and for determination of the position of the vehicle (10): i at least three angle values with a suitable distribution over the search sector is selected, ii the angle values are associated to reflectors and a position is determined for the vehicle on the basis of the known position of the assumed reflectors, iii if the vehicle position determined in this way is within a certain part of the transport area the other angle values are associated to reflectors, iv for each angle value, existing deviation is determined between detected angle values and angle values expected between the vehicle position and known reflectors, v the measures taken are repeated for each possible combination of selected angle values.
最初使用下列步骤使这些角位与反射器关联以便确定车辆(10)的位置:i)在该搜索扇形上选择至少三个合适分布的角度值,ii)使各角度值与各反射器关联,根据假设反射器的已知位置确定车辆的位置,iii)如果如此确定的车辆位置在该运输区的某一部分中,则使其他角度值与反射器关联,iv)对于每一角度值,确定所检测角度值与车辆位置与己知反射器之间预期角度值之间的偏差,v)对于所选择的角度值的每一种可能组合反复进行这些步骤。
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This article analyses the application conditions of freezing method, current research status and the problems in this field. It points that it's necessary to study deep freezing temperature field deeply and discusses the factors which influence the freezing wall such as soil's nature, moisture content, geological conditions, etc. It introduces the theory, process of freezing method, the distribution of temperature field of freezing method and key thermotics parameters influencing freezing temperature field. It simplifies the deep freezing temperature field model. Through ANSYS, this article founds the deep freezing temperature field model, and simulates the field on vary heat conductivities. It analyzes the results of ANSYS simulation, gains the theoretical value of thermometric holes which is needed by back-analysis. Using the simulation temperature and actual value, it gets the equivalent heat conductivity. Then it solves the deep freezing temperature field by the equivalent value, simulates the freezing wall development process and temperature change curve. Against the actual project, the results are favorable.
文中分析了冻结法施工的应用条件,目前对冻结法施工的研究现状和在此领域内存在的问题,指出了对深土冻结温度场进行深入研究分析的必要性;对影响冻结壁形成发展的因素如冻土土性、含水量、地质条件及施工方法等因素进行了论述;对冻结法施工的原理、过程,冻结法温度场的分布情况,影响冻结温度场分布的主要热学参数进行了综述;对深土冻土温度场模型进行了合理的简化,通过ANSYS大型有限元分析软件,建立了深土冻结温度场的模型,对不同导热系数情况下的深土冻结温度场进行了模拟;对ANSYS的模拟结果进行了定性的分析,通过对ANSYS结果的后处理取得了反分析时需要用到的测温孔理论温度值;经过对测温孔模拟温度值和实测温度值的分析,得到了冻结温度场的等效导热系数;使用等效导热系数对深土冻结温度场进行了求解,模拟了冻结壁发展情况和温度场中的温度变化曲线,用所得结果对比工程实际情况,取得了较好的效果。
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This article analyses the application conditions of freezing method, current research status and the problems in thisiold. It, points that it" s necessary to study deep freezing temperature field deeply and discusses the factors which influence the freezing wall such as soil" s nature, moisture content, geological conditions, etc. It introduces the theory, process of freezing method, the distribution of temperature field of freezing method and key thermotics parameters influencing freezing temperature field, it simplifies the deep freezing temperature field model. Through ANSYS, this article founds the deep freezing temperature field model, and simulates the field on vary heat conductivities. It analyzes the results of ANSYS simulation, gains the theoretical value of thermometric holes which is needed by back analysis. Using the simulation temperature and actual value, it gets the equivalent heat conductivity. Then it solves the deep freezing temperature field by the equivalent value, simulates the freezing wall development process and temperature change curve. Against the actual project, the results are favorable.
文中分析了冻结法施工的应用条件,目前对冻结法施工的研究现状和在此领域内存在的问题,指出了对深土冻结温度场进行深入研究分析的必要性;对影响冻结壁形成发展的因素如冻土土性、含水量、地质条件及施工方法等因素进行了论述;对冻结法施工的原理、过程,冻结法温度场的分布情况,影响冻结温度场分布的主要热学参数进行了综述;对深土冻土温度场模型进行了合理的简化,通过ANSYS大型有限元分析软件,建立了深土冻结温度场的模型,对不同导热系数情况下的深土冻结温度场进行了模拟;对ANSYS的模拟结果进行了定性的分析,通过对ANSYS结果的后处理取得了反分析时需要用到的测温孔理论温度值;经过对测温孔模拟温度值和实测温度值的分析,得到了冻结温度场的等效导热系数;使用等效导热系数对深土冻结温度场进行了求解,模拟了冻结壁发展情况和温度场中的温度变化曲线,用所得结果对比工程实际情况,取得了较好的效果。
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To a one-dimension case, the solution to the distribution of non-monotone function is given; to a two-dimension case, the transformation of random variable and the computation formula of its probability density are given when inverse transform has one value and multiple value, meanwhile, several deductive conclusions are obtained.
从一维与二维随机变量函数的分布的一般求法出发,对一维情形,给出了当随机变量函数非单调时其分布的求法;对二维情形,用随机变量变换的方法分别给出了当逆变换单值与多值时其分布密度的计算公式,并得到了若干推论。
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An assumed Gaussian tail is addedonto the HO distribution. The calculations for〓 of the protron-rich isotones 〓〓 and 〓 and for 〓 the neutron-rich isotopes 〓were finished by theGlauber Model along with the modified density distrution. The calculated resultsshow that d values of these nuclei along with the modified density distribution arelower than the calculated ones along with the only HO density distribution.
为减小Glauber模型计算的反应截面与实验值的差别,本论文还对Glauber模型的输入密度形式进行了修改,在原单-HO分布基础上加一个高斯分布的尾巴,并对丰质子的同中子素核〓及〓与〓靶以及〓和丰中子的C同位素核〓与〓靶的反应截面重新进行了计算,结果显示在中能区的计算值比原来单一密度分布的计算结构有明显改善。
- 推荐网络例句
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But we don't care about Battlegrounds.
但我们并不在乎沙场中的显露。
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Ah! don't mention it, the butcher's shop is a horror.
啊!不用提了。提到肉,真是糟透了。
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Tristan, I have nowhere to send this letter and no reason to believe you wish to receive it.
Tristan ,我不知道把这信寄到哪里,也不知道你是否想收到它。