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1.
The effect of different combinations of size and orientation of rectangular blades of a wet land puddler, on puddling index, force requirement and performance index was investigated under controlled conditions in a soil-bin from the study. It was observed with the blade size of 15-cm width × 8.5-cm depth and a blade angle of 30° with respect to shaft gave better performance than other combinations in terms of minimum puddling index, minimum horizontal force, vertical force, specific energy and maximum performance index. The values are, respectively, 67.95%, 105.12 N, 33.85 N, and 9.71 kJ/m3 and 6.69. The above-mentioned parameters of the blade were found to be very close to the predicted values obtain through MREG computer programme for optimization of size and orientation of puddler blades. 相似文献
2.
一种新的铁谱磨损监测定量参数 总被引:2,自引:1,他引:2
在工程实际中,铁谱磨损监测技术已经获得广泛应用,但其主要缺点是所用特征参数不能直接反映机械设备的磨损劣化程度.为了弥补现用铁谱定量分析参数的不足,提出了一种新的铁谱磨损监测定量参数——劣化值.这种参数的优点是使被监测对象的磨损劣化程度具有直观性和可比.为了避免使用一种铁谱定量参数的劣化值进行磨损状态判别时存在的片面性,运用模糊评判理论,引入综合劣化值概念,建立了评判标准;针对引入的劣化值,开发了相应的数据处理系统,用于劣化值计算及磨损状态判别.应用实例表明,劣化值的引入,不仅提高了铁谱定量参数的直观性,而且还实现了不同机械铁谱定量参数的可比性,能够反映机械设备磨损劣化状态的轻重程度 相似文献
3.
袁镒吾 《应用数学和力学(英文版)》1992,13(7):649-655
In ref I, under the condition that the components of velocity are only the functions of time and polar angle θ, Drornikov solved eqss. (1.1) (1.3) of the ideal gas unsteady planar parallel potential flow. It was pointed out in ref. [1] that in general cases, the evident solutions could not he obtained. Only for two especial cases, the evident solutions were obtained.In this paper, the author studies the same prohlein as that in ref. [1]. In the first section we obtain the evident solution of equations (1.1)-(1.3) under the condition that the sonic velocity is restricted by some complemental conditions. In the second section, we obtain the first-order approximate solutions of the fundamental equation for the case that γ>>1 相似文献
4.
结构可靠指标矢量及其计算与应用 总被引:5,自引:0,他引:5
从结构可靠指标的几何意义出发 ,提出了可靠指标矢量 ,并给出了它的计算方法。理论分析和算例结果表明 :可靠指标矢量既可表达可靠指标 ,又可方便地表示各失效模式之间的相关性。可靠指标矢量可较好地解决长期困扰结构体系可靠度分析和应用的难点之一——怎样计算各失效模式之间的相关性。 相似文献
5.
Marian Mrozek 《Journal of Dynamics and Differential Equations》1999,11(4):711-734
We introduce a class of representable sets which is closed under the operations of set theoretical union, intersection, difference, and topological interior and closure. We use this class to construct an algorithm which verifies if for a given dynamical system a given set is an isolating neighborhood. In the case of a positive answer the algorithm constructs an index pair. 相似文献
6.
7.
The wettability of a crude oil/brine/rock system is of central importance in determining the oil recovery efficiency of water displacement processes in oil reservoirs. Wettability of a rock sample has traditionally been measured using one of two experimental techniques, viz. the United States Bureau of Mines and Amott tests. The former gives the USBM index, I
USBM, and the latter yields the Amott–Harvey index, I
AH. As there is no well-established theoretical basis for either test, any relationship between the two indices remains unclear.Analytical relationships between I
AH and I
USBM for mixed-wet and fractionally-wet media have been based on a number of simplifying assumptions relating to the underlying pore-scale displacement mechanisms. This simple approach provides some guidelines regarding the influence of the distribution of oil-wet surfaces within the porous medium on I
AH and I
USBM. More detailed insight into the relationship between I
AH and I
USBM is provided by modelling the pore-scale displacement processes in a network of interconnected pores. The effects of pore size distribution, interconnectivity, displacement mechanisms, distribution of volume and of oil-wet pores within the pore space have all been investigated by means of the network model.The results of these analytical calculations and network simulations show that I
AH and I
USBM need not be identical. Moreover, the calculated indices and the relationship between them suggest explanations for some of the trends that appear in experimental data when both I
USBM and I
AH have been reported in the literature for tests with comparable fluids and solids. Such calculations should help with the design of more informative wettability tests in the future. 相似文献
8.
本文分析了旋转载体上离心力造成的干涉测量光路中空气介质压强的不均匀变化,给出了与光路介质折射率相应的分布规律,分析了由此引起的干涉测量系统动态测量的示值偏差,据此分析计算的结果可用于测量结果的精密修正。本文的讨论结果为精密离心机及类似的运动载体上的动态干涉测量系统的分析设计提供了依据。 相似文献
9.
云天铨 《应用数学和力学(英文版)》2001,(1)
1 MeaningandMethodsofStudyingofFinancialDerivativesFinancialderivativesarethosefinancialproductswhicharederivedfrombasicasserts (orunderlyinginstrucments) (e .g .stock ,bond ,currency ,interestrate,etc.)oftraditionalmarkets(e.g .stockmarket,bond’smarket,currency… 相似文献
10.
云天铨 《应用数学和力学(英文版)》2001,22(1):118-125
Similar to the method of continuum mechanics, the variation of the price of index futures is viewed to be continuous and regular. According to the characteristic of index futures, a basic equation of price of index futures was established. It is a differential equation, its solution shows that the relation between time and price forms a logarithmic circle. If the time is thought of as the probability of its corresponding price, then such a relation is perfectly coincided with the main assumption of the famous formula of option pricing, based on statistical theory, established by Black and Scholes, winner of 1997 Nobel’ prize on economy. In that formula, the probability of price of basic assets (they stand for index futures here) is assummed to be a logarithmic normal distribution. This agreement shows that the same result may be obtained by two analytic methods with different bases. However, the result, given by assumption by Black-Scholes, is derived from the solution of the differential equation. 相似文献
11.
在基于光杠杆原理检测微悬臂梁变形的生化传感实验系统中,液体折射率的变化会导致PSD上光斑的位移,从而影响系统的检测信号。本文从理论上分析了在不同检测光束的入射角度、微梁的放置角度等参数条件下,液体折射率的变化对系统检测信号的影响。结果表明:在传统的光路下,液体折射率改变10-3引起的光斑位移与一般的生化反应引起的位移相当,即液体折射率的改变严重影响系统的检测信号。通过理论分析还发现在适合的参数配置下,可以忽略折射率变化对系统检测信号的影响。同时,参数的改变不影响系统的检测灵敏度。理论分析的结果得到了实验验证。 相似文献
12.
Numerical simulation on micromixer based on synthetic jet 总被引:1,自引:0,他引:1
This paper studied a concept of micromixer with a synthetic jet placed at the bottom of a rectangular channel. Due to periodic ejections from and suctions into the channel, the fluids are mixed effectively. To study the effects of the inlet velocity, the jet intensity and frequency, and the jet location on the mixing efficiency, 3-D numerical simulations of the micromixer have been carried out. It has been found that when the jet intensity and the frequency are fixed, the mixing efficiency increases when Re 〈 50, and decreases when Re 〉 50 with the best mixing efficiency achieved at Re = 50. When the ratio of the jet velocity magnitude to the inlet velocity is taken as 10 and the jet frequency is 100 Hz, the mixing index reaches the highest value. It has also been found that to get better mixing efficiency, the orifice of the synthetic jet should be asymmetrically located away from the channel's centerline. 相似文献
13.
Shunsaku Nii 《Journal of Dynamics and Differential Equations》1996,8(4):549-572
We study bifurcations, calledN-homoclinic bifurcations, which produce homoclinic orbits roundingN times (N2) in some tubular neighborhood of original homoclinic orbit. A family of vector fields undergoes such a bifurcation when it is a perturbation of a vector field with a homoclinic orbit.N-Homoclinic bifurcations are divided into two cases; one is that the linearization at the equilibrium has only real principal eigenvalues, and the other is that it has complex principal eigenvalues. We treat the former case, espcially that linearization has only one unstable eigenvalue. As main tools we use a topological method, namely, Conley index theory, which enables us to treat more degenerate cases than those studied by analytical methods. 相似文献
14.
In recent years, water disasters have increased in Japan. In water disaster, remote controlled vehicles which work for disaster recovery must run in water environment. Since underwater ground is likely to be soft, the vehicle has a risk of stuck. If a vehicle gets stuck at disaster sites, rescue work is difficult because it is not easily to access to that area. We must make a method for judging whether to run or not. For this purpose, we must quantitatively clarify the relationship between the trafficability and the strength, bearing capacity, etc. of underwater ground. We measured the cone index of underwater ground. From results, we confirmed that fragile layer was formed on the surface layer in underwater ground. We measured drawbar pull of a tracked carrier in test field. As a result, maximum drawbar pull of underwater ground was lower than on the ground. After slip occurs, drawbar pull of underwater ground was smaller than ground significantly. 相似文献
15.
一种结构可靠性指标的搜索方法 总被引:1,自引:0,他引:1
提出了一种计算结构可靠性指标的搜索方法,即自动变步长搜索方法。该方法克服一次二阶矩方法的缺点,对于非线性功能函数非常有效。数值例题表明:这种方法具有很好的收敛性和较高的计算精度,且其收敛性与初始步长无关,可以用于复杂问题可靠度的分析。 相似文献
16.
In this paper, we prove that a stable isolated fixed point of an orientation preserving local homeomorphism onR
2 has fixed point index 1. We also give a number of applications to differential equations. In particular, we deduce that a number of existence methods for producing periodic solutions of differential equations in the plane always produce unstable solutions. 相似文献
17.
Jos E. F. Rubio Jesús M. Arsuaga Mercedes Taravillo Valentín G. Baonza Mercedes Cceres 《Experimental Thermal and Fluid Science》2004,28(8):511-891
Measurements of the refractive index from 288 to 318 K at five fixed wavelengths, from 656.3 to 404.7 nm, are reported for benzene, toluene (methylbenzene), o-xylene (1,2-dimethylbenzene), m-xylene (1,3-dimethylbenzene), and p-xylene (1,4-dimethylbenzene). We also report the temperature and wavelength dependencies of the refractive index obtained from a least-squares routine. The agreement between the measured and calculated refractive indices lies within the experimental uncertainty. 相似文献
18.
Correlation dimension of paddy soil strength in China 总被引:2,自引:0,他引:2
Embedding phase space Rm is reconstructed from the spatial series g(x) of cone indices measured in two paddy fields near Nanjing, China. The correlation dimension D2m for each field is derived from the correlation integral Cm(r) and the neighbours distance r in log–log scale. Results show D2m increases as m, and tends to 5.0, which expresses the estimate of correlation dimension for each soil strength profile measured. 相似文献
19.
Tomáš Gedeon Hiroshi Kokubu Konstantin Mischaikow Hiroe Oka 《Journal of Dynamics and Differential Equations》2002,14(1):63-84
We study a slowly varying planar Hamiltonian system modeling shallow water sloshing. Using the Conley index theory for fast-slow systems of ODEs, we prove the existence of complicated dynamics in the system which is described in terms of symbolic sequences of integers. This includes the solutions proven by Hastings and McLeod as well as those conjectured by them. 相似文献