查询词典 threshold friction

In order to reasonably depict four basic problems with friction, one Coulomb friction new form in first Kirchhoff stress is proposed to deal with finite deformation problems, other Coulomb friction form in incremental mode to elastoplastic flow theory; Hilbert function spaces concerning elastoplastical problems with friction are established, so it makes all operations and calculations in the treatise standardized within the scope of reasonably topologic structure; In view of functional extremum, the equivalence between generalized variational inequalities principles in elastoplasticity with friction and corresponding basic problems are testified by inducing Lagrangian multipliers, so it provides a rationally theoretical basis for numerical methods in elastoplasticity with friction; From the viewpoint of variational inequality, the theory of generalized variational inequalities in elasticity and elastoplasticity with frictional constraint is studied, and the uniqueness and existence of the solution of FEM is proofed under the proposed conditions of stress compatibility, and them FEM approximation and a discrete solution are discussed; Based on the principles of generalized variational inequalities in elastoplasticity with friction, direct generalized variational inequalities methods is pretended, which is a natural generalization and development of direct variational methods; Using generalized variational inequalities methods, some examples in metal forming including plane deformation, upset and extrusion are analyzed and the results prove that all the theories and methods in the paper are right, feasible, accurate and advanced.

主要内容有：为了合理地描述金属塑性成形中摩擦约束弹性、弹塑性基本问题，提出和研究了有限变形下以Kirchhoff第一应力表示的Coulomb摩擦定律形式和弹塑性流动理论下以增量形式表示的Coulomb摩擦定律表示形式；系统建立了摩擦约束弹塑性问题的Hilbert函数空间，使本文规范在一个具有合理的代数拓扑结构内进行一切操作和运算；利用Lagrange乘子，从泛函极值的角度系统地阐述和论证了一系列摩擦约束弹性、弹塑性广义变分不等原理与相应的实际问题之间的等价性，它为处理摩擦约束的弹塑性力学数值方法提供了合理的理论基础；从变分不等式的角度出发，阐述了对应于摩擦约束弹性、弹塑性问题的广义变分不等式理论，首次提出了在应力相容性条件下，它的有限元解具有存在唯一性，进而讨论了其有限元近似及离散解法；基于摩擦约束弹塑性广义变分不等式原理，首次提出了直接广义变分不等式方法，这一方法是直接变分法的合理推广和发展；利用直接广义变分不等式方法对金属压力加工中的平面变形问题、镦粗、挤压等塑性成形问题进行了分析计算，验证了该理论和数值算法的正确性、实用性、精确性和优越性。

Friction are many ways to fitness, with a dry towel friction body, known as "dry cloth friction"; with a soft brush friction, known as "brush friction"; with a cold towel wrung friction is called "cold-water friction"; also can be used "hand-rub the Law" and so on.

磨擦健身的方法很多，用干毛巾磨擦全身，叫作&干布磨擦&；用柔软的刷子磨擦，称为&刷子磨擦&；用拧干的冷毛巾磨擦叫&冷水磨擦&；此外还可以采用&手擦法&等等。

Based on much resolutional analysis wavelet threshold de-noising method ,an improved threshold function is proposed. it overcomes the shortcomings of the hard threshold with discontinuous function ang solves the problem of the permanent bias in soft threshold function,and it is more elastic than the soft threshold and hard threshold function.

在多分辨分析小波阈值去噪的基础上，采用了一种改进的阈值函数，克服了硬阈值函数不连续的缺点，解决了软阈值函数中存在的恒定偏差，并且具有软硬阈值函数不可比拟的灵活性。

The threshold determining device (10) determines a similarity of each data to others for each data, determines the threshold of the similarity satisfying a predetermined coincidence/incoincidence, for each data, determines an individual threshold distribution of the data for each threshold on each of the data, and determines the threshold common to the entire data, as overall data on the basis of the individual threshold distribution.

阈值确定设备针对每个数据确定每个数据相对于其它数据的相似性，针对每个数据确定满足预定假匹配率的相似性的阈值，针对每个数据的每个阈值确定数据的个体阈值分布，并且根据个体阈值分布将全部数据共用的阈值确定为整体数据。

The rule of dry sliding friction wear of vermicular iron was analyzed. The influence of working conditions, composition and structure on dry sliding friction characteristics was investigated, 3D morphologies of friction surfaces of vermicular iron and temperature characteristics of friction surface were discussed. The results showed that, compared with nodular and gray irons, vermicular iron has lowest wear rate, highest friction coefficient and lowest friction coefficient attenuation, so it is suitable to be as the material of braking device.

分析了蠕墨铸铁的干滑动摩擦磨损规律，研究了工况条件、成分、组织对蠕墨铸铁干滑动摩擦学特性的影响，探讨了蠕墨铸铁摩擦表面二维形貌与摩擦表面温度特性，结果表明：蠕墨铸铁与球墨铸铁和灰铸铁相比具有最低的磨损率和最高的摩擦系数与最低的摩擦系数衰减量，适合于作为制动器材料。

The law of factors' affecting degree, which influences the parameters between geogrids and soils in the pulling-out procedure, is obtained. With the concept of 'equivalent pull-out displacement' brought forward, the whole process of pull out tests is divided into two process-" main process (when x 1.0)" and "residual process (when x 1.0)", and three stages-static friction resistance stage, slip friction resistance stage, and residual friction resistance stage.2 The value of friction coefficient between reinforcement and soil varies with their definitions of friction, but each factor' s affecting degree influencing friction pa

将模糊控制理论引入了岩土工程过程分析，考虑影响因素影响程度的变化及其规律，提出了一套可供岩土工程过程分析中参数选择的分析方法，并在筋土界面相互作用参数选取的拉拔试验过程控制中获得实施，为应用有限元法对加筋土结构进行过程中南大学博士论文摘要分析提供了参数选择的新方法；将模糊聚类分析方法应用于加筋土陡边坡状态评定，并提出侧向位移可作为加筋土边坡状态评定的量化指标，而不同类型边坡的侧向位移允许控制值可仿效此法结合工程经验确定。

The new threshold function overcomes the shortcomings of the hard threshold with discontinuous function and solves the problem of the permanent bias in soft threshold function,and it is more flexible than the soft threshold and hard threshold function.

新阈值函数克服了传统硬阈值函数不连续的缺点，解决了软阈值函数中存在的恒定偏差，并且具有软硬阈值函数不可比拟的灵活性。

The plasma ignition threshold of metal is got through experimental and numerical study. The vapour and plasma ignition times of the target are got based on the equation of heat conduction and cascade model. We suppose that the plasma is ignited when generations of new electrons are born in vapour generation time. The influence of temperature on the thermodynamics and optics parameters of material also have been considered in the model. The resulting theory has good agreement with the experiment and overseas report. A blade method to measure the laser spot is given in this paper with validation and error analysis. The plasma threshold of metals in atmosphere and water ambients both are diagnosed with the light deflection and piezoelectric transducer. A Q-switched pulsed Nd:YAG laser operating at infrared (1064nm), visible(532nm) and ultraviolet (355nm) wavelengths has been used. Al、Fe、Cu are used as targets and get a similar results with both method. Theoretical and experimental analyses are applied on the influence of wavelength on the threshold have been done, both of which have shown that the plasma threshold of metals decrease as the laser wavelength increases; The plasma threshold of metals are higher in water than in air and the pressure of the shock wave in water is five times higher than in air .

从热传导方程和雪崩电离机制出发，假设当电子增值210倍时，考虑了温度对材料热力学和光学参数的影响时，得到了气化和等离子体点燃的时间，利用该模型进行计算得到的结果与国内外报道及自行通过实验测得的阈值基本一致；提出了利用刀刃法测量激光光斑面积的方法，并通过实验进行了验证和误差分析；利用光偏转装置和压电换能器分别对空气和水中金属等离子体点燃阈值进行了实验诊断，激光器均为调Q－YAG激光器（波长1064nm，532nm，355nm，脉宽10ns），靶材分别为Al、Fe和Cu，两种测试方法得到的等离子体点燃阈值基本一致；本文从实验和理论计算两个方面讨论了波长对等离子体点燃阈值的影响，均得到了等离子体点燃阈值随著波长的增加而减小的结论；对空气中和水中不同环境下金属等离子体的点燃阈值进行了比较研究，得到了金属在水中的等离子体点燃阈值比空气中的大，且水中产生的冲击波的压强是空气中的5倍左右的结论。

The friction performances of carbon face were investigated with an inertia friction tester. The torque curve of carbon face was ideal, the coefficient of static friction was lower than that of dynamic in 0.28 MPa, the friction coefficient of static and dynamic decreased with the braking pressure increasing. To the fiber face, the coefficient of dynamic friction of carbon face was more stable in cycle braking process, the wear rate was lower, and it was efficient to protect the couple plate not to be worn.

结果表明：碳质层的摩擦力矩在制动初期上升较快，中间过渡区平稳，尾部翘起较小；在制动压力小于0.28 MPa时静摩擦系数小于动摩擦系数，且动、静摩擦系数均随制动压力增加而减小；相对纤维层而言，采用碳质层摩擦时摩擦力矩曲线形态更好，连续制动时摩擦系数波动较小，磨损率低且能够有效保护偶件，是1种静/动摩擦系数比较低且适用于高载荷工况条件下使用的摩擦材料。

It is difficult to measure the static friction coefficient of the material like polyurethane. The state of friction under very low velocity with small sliding distance is a special state between static and dynamic friction. This state of friction can be called initial stages'friction.

聚氨酯弹性体材料的静摩擦系数是比较难以确定的，本文建议把滑动量较小而滑动速度又很低的这一时期的摩擦称为"初期摩擦"，它是界于静摩擦与动摩擦之间的一种特殊的摩擦状态。

Although translator has turned from being a crystal ball by which the original culture can unrestrainedly penetrate to another crystal ball by which the target culture can freely traverse, the translator's personal embodiment, in the process of cognitive act, are still absent in translation studies. Translators are still subjects without body or simply disembodied subjects.

译者虽然由原语文化可以自由穿透的玻璃球变成了译语文化可以自由穿越的玻璃球，但译者认知过程中的个体体验在翻译研究中依然缺席，译者依然仅仅是一个没有躯体体验的主体。

Chillingly, he claimed our technology is 'not nearly as sophisticated' as theirs and "had they been hostile", he warned 'we would be been gone by now'.

令人毛骨悚然的，他声称我们的技术是'并不那么复杂，像他们一样，和"如果他们敌意"，他警告说，'我们将现在已经过去了。