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The biological function of a protein is mainly maintained by its three-dimensional structure. Protein folds support the three-dimensional structure of a protein, and then the inter-residue contacts in the protein impact the formation of protein folds and the stability of its protein structure. Therefore, the protein contact plays a critical role in building protein structures and analyzing biological functions. In this thesis, we propose a methodology to predict the residue-residue contacts of a target protein and develop a new measurement to evaluate the accuracy of prediction. With three prediction tools, the support vector machine (SVM), the k-nearest neighbor algorithm (KNN), and the penalized discriminant analysis (PDA), we compare these classifiers based on the self-testing of the training set, which are derived from representative protein chains from PDB (PDB-REPRDB), and apply the best (SVM) to predict a testing set of 173 protein chains derived from previous study. The experimental results show that the accuracy of our prediction achieves 24.84%,15.68%, and 8.23% for three categories of different contacts, which greatly improves the result of random exploration (5.31%, 3.33%, and 1.12%, respectively).

This study calculate the frictional temperature of the dissimilar metal pair by theoretical analysis. Analyze the frictional temperature rise at interface dividing into the flash temperature rise and the bulk temperature rise. According the frictional temperature rise, establish the model of the temperature rise at the first cycle and the quasi-steady state cycle. And then discuss the condition of asperity contact by the measurement of experimental temperature rise. In the bulk temperature rise and the flash temperature rise, compare with the exact solution, the approximate solution of the average temperature rise that we derived have little error in specific range of Peclet number. Combine the approximate solution of the bulk temperature rise and the flash temperature rise to calculate the temperature rise of asperity contact at rubbing interface. We can evaluate the average contact length of asperity by measured values.

Abstract The interaction among the tooth wear, dynamic loads, and its corresponding frequency spectrum variation in a spur gear pair is investigated in the dissertation. A mathematical model for the dynamic responses of a profile shifting involute gear pair is derived. For simplicity, a two-step mesh stiffness model is proposed to approximate the load sharing and the time-varying stiffness effects in a mating gear pair. The analytic solutions for the dynamic responses of this simplified dynamic model are derived in both time and frequency domains. The effect of the tooth wear on the spectrum variation has been illustrated analytically. The amplitude and frequency modulations introduced from the periodic load fluctuation have also been discussed. In order to characterize the time-varying mesh stiffness, frictional coefficient, damping ratio, temperature rise and load sharing effects between engaged teeth, a computational algorithm with the quasi-linear iteration procedure is developed to include above instantaneous parameters in the teeth engagement process. The tooth wear equation proposed by Flodin and Andersson (1997) is employed to simulate the mild wear process for an engaging gear pairs. The interactions between the tooth wear and the dynamic loads for the Steel/Steel, POM/POM, Nylon/Nylon and Steel/Nylon gears pair have been studied numerically. Numerical examples indicate that the proposed models are valid for gear pairs with different materials.

Diss.--Duisburg, 2001. / Bibliogr. p. 303-334.

Texte remanié de: Dissertation--Halle-Wittenberg--Martin-Luther Universität, 2005. / Bibliogr. p. 327-346.

Avhandling--Göteborg, 1997. / Bibliogr. p. 405-422. Résumé en anglais.

Texte remanié de: Thèse de doctorat--Sciences du langage--Grenoble 3, 2006. / Bibliogr. p. 529-538.

Thèse d'exercice : Pharmacie : Université de Nantes : 2003. / Bibliogr. f. 78-85 [113 réf.].

Thèse doctorat : Mécanique : Villeurbanne, INSA : 2005. / Titre provenant de l'écran-titre. Bibliogr. p. 155-162.