过冷大水滴结冰多参数敏感性分析

过冷大水滴结冰现象对飞机的安全运行造成了严重的威胁。本文采用Sobol序列采样法、径向基函数法、Sobol’s敏感性指数分析法对结冰表面粗糙度、冰密度、有无蒸发、水滴尺寸分布、步长数进行分析,通过单一参数的一阶敏感性指数表征其对冰形参数的影响程度,通过总敏感性指数比较上述参数之间的相互作用对结冰冰形或结冰量的影响。研究发现,翼型前缘冰形特征参数对上述各参数的敏感性存在一致性规律,均受结冰表面粗糙度影响最大,总敏感指数大于0.4761,而受步长数影响最小,约为0.2,其余参数的影响程度从大到小依次为蒸发、水滴尺寸分布和冰密度.

应用特征性几何参数研究髋关节发育不良导致骨性关节炎的生物力学机制

目的：探讨发育性髌关节脱位（DDH）的特征性几何参数、髋关节生物力学的改变导致骨性关节炎的机制，为临床诊治发育性髋关节发育不良、防止骨性关节炎的发生提供依据。方法：通过Pubmed、中国知网等检索近几年国内外关于正常髋关节、DDH的特征性几何参数与接触应力的相关文献，对发育性髋关节发育不良导致骨性关节炎的生物力学机制的相关研究进行汇总分析。结果：DDH患者的髋关节的特征性几何参数变化导致髋关节力学环境发生变化，并最终导致骨性关节炎。结论：对于发育性髋关节发育不良患者，早期纠正其特征性几何参数，可以延缓或阻止骨性关节炎的发生。

高凝油藏水淹层精细评价的分析处理方法

针对辽河沈 84块沙三段高含水期高凝油藏储层水淹状况和特征 ,依据灰色系统油田开发分析方法及准则 ,利用测井、钻井取心、试油及有关地质资料 ,匹配、拟合和提取参数 ,分别以其特征性参数对高含水期油藏岩性、物性和水淹状况进行统计 ,提出和建立了精细评价高凝油藏水淹层的参数、标准、权系数和解释系统。通过该区沙三下 174口井水淹层的精细评价处理 ,阐明了区块沙三下高凝油藏水淹状况及剩余油纵向分布规律。还给出了该方法、软件的主要处理和实际应用的例子。

Self-heating tendency evaluation of sulfide ores based on nonlinear multi-parameters fusion

In order to reveal the nonlinear dynamics characteristics of unsteady self-heating process of sulfide ores, nine different kinds of sulfide ore samples from a pyrite mine in China were taken as experimental materials and their self-heating characteristics were measured in laboratory. Furthermore, the measured temperature was studied by integrating wavelet transform, nonlinear characteristic parameters extraction and fuzzy comprehensive evaluation. The results indicate that only the ore samples 1, 2, 6 and 9 have obvious self-heating phenomenon, and their self-heating initiative temperatures are 220 ℃, 239 ℃, 220 ℃ and 220 ℃, respectively, which means that they are difficult to produce self-heating under normal mining conditions. The correlation dimension of self-heating process is fraction and the maximum Lyapunov exponent is positive, which means that it is feasible to study the self-heating process based on chaotic dynamics theory. The nonlinearities of self-heating process of these four samples （ore samples 1, 2, 6 and 9） are 0.8227, 0.7521, 0.9401 and 0.8827 respectively and the order of the samples according to these results is： sample 6, sample 9, sample 1, sample 2, which is consistent with the measured results of self-heating characteristics. Therefore, the nonlinearity method can be used to evaluate the self-heating tendency of sulfide ores, and it is an effective verification of the reliability of measured results.

谷间软弱土路基稳定性计算方法研究

山区谷间路基的稳定性计算,目前仍沿用传统极限平衡的方法,未考虑山谷对路基的约束及谷间软弱土对路基稳定性的影响.依据谷间锅底状软弱土层存在形式,以及邻近山体等对路基稳定性约束的影响,确定了谷间软弱土路基稳定性的特征性描述参数以及修正系数计算方案,并得到了在山体与坡脚的距离和不同软弱土形式下的路基稳定性修正系数计算公式.通过工况对比,发现计算结果与采用本文中提出的稳定性修正系数计算出的安全系数两者相近,论证了本文提出的稳定性修正系数计算公式的可行性.

Characteristics of turbulent flow distribution in branch piping system

Flow distribution in branch piping system is affected by flow characteristics and different geometric variations. Most of the flow distribution studies are performed with one-dimensional analysis to yield overall information only. However, detailed analysis is required to find effects of design parameters on the flow distribution. For this aspect, three-dimensional turbulent flow analysis was performed to assess turbulence model performance and effects of upstream pressure and branch pipe geometry. Three different turbulence models of standard k-e model, realizable k-e model and standard k-co yield similar results, indicating small effects of turbulence models on flow characteristics analysis. Geometric variations include area ratio of main and branch pipes, branch pipe diameter, and connection shape of main and branch pipes. Among these parameters, area ratio and branch diameter and shape show strong effect on flow distribution due to high friction and minor loss. Uniform flow distribution is one of common requirements in the branch piping system and this can be achieved with rather high total loss design.

Inverse Eigenvalue Problems for a Structure with Linear Parameters

The inverse design method of a dynamic system with linear parameters has been studied. For some specified eigenvalues and eigenvectors, the design parameter vector which is often composed of whole or part of coefficients of spring and mass of the system can be obtained and the rigidity and mass matrices of an initially designed structure can be reconstructed through solving linear algebra equations. By using implicit function theorem, the conditions of existence and uniqueness of the solution are also deduced. The theory and method can be used for inverse vibration design of complex structure system.

Asymptotic Behavior of Soliton Solutions with a Double Spectral Parameter for Principal Chiral Field

The soliton solutions with a double spectral parameter for the principal chiral field are derived by Darboux transformation. The asymptotic behavior of the solutions as time tends to infinity is obtained and the speeds of the peaks in the asymptotic solutions are not constants.

THE STATISTIC ANALYSIS OF SCREEN PARAMETERS ON PERFORMANCE CHARACTERISTICS

A series of laboratory screening tests have been performed with the objective of evalu-ating the effect of feed rate, screen length and screen motion on the quality of separation achieved. The statistic analysis and results derived from it are discussed. Suggestions for future work with the objective of assessing the industrial significance of the research to the optimisation and design of screening processes are presented.

Optimization of Performance and Emission Characteristics of PPCCI Engine fuelled with Ethanol and Diesel blends Using Grey-Taguchi Method

The performance and emission characteristics of a PPCCI engine fuelled with ethanol and diesel blends were car- ded out on a single cylinder air cooled CI engine. In order to achieve the optimal process response with a limited number of experimental cycles, multi objective grey relational analysis had been applied for solving a multiple response optimization problem. Using grey relational grade and signal-to-noise ratio as a performance index, a combination of input parameters was prefigured so as to achieve optimum response characteristics. It was observed that 20% premixed ratio of blend was most suitable for use in a PPCCI engine without significantly affecting the engine performance and emissions characteristics.

Local multifractal detrended fluctuation analysis for tea breeds identification

In recent years, the popular multifractal detrended fluctuation analysis （MF-DFA） is extended to two-dimensional （2D） version, which has been applied in some field of image processing. In this paper, based on the 2D MF-DFA, a novel multifractal estimation method for images, which we called the local multifractal detrended fluctuation analysis （LMF-DFA）, is proposed to recognize and distinguish 20 types of tea breeds. A set of new multifractal descriptors, namely the local multifractal fluctuation exponents is defined to portray the local scaling properties of a surface. After collecting 10 tea leaves for each breed and photographing them to standard images, the LMF-DFA method is used to extract characteristic parameters for the images. Our analysis finds that there are significant differences among the different tea breeds＇ characteristic parameters by analysis of variance. Both the proposed LMF-DFA exponents and another classic parameter, namely the exponent based on capacity measure method have been used as features to distinguish the 20 tea breeds. The comparison results illustrate that the LMF-DFA estimation can differentiate the tea breeds more effectively and provide more satisfactory accuracy.