La réparation des cassures double brin (CDB) de l'ADN par recombinaison est essentielle au maintien de l'intégrité du génome de tous les être vivants. Ce processus doit cependant être finement régulé puisque la recombinaison peut générer des mutations ou des réarrangements chromosomiques, parfois extrêmement délétères pour la cellule. Les CDB peuvent être réparées par deux mécanismes : la recombinaison non homologue (ou jonction des extrémités d'ADN) ou la recombinaison homologue (impliquant une homologie de séquence entre les molécules recombinantes). Dans les cellules somatiques, les deux voies principales de recombinaison homologue (RH) sont la voie Synthesis Dependent Strand Annealing (SDSA) dépendante de la recombinase RAD51 et la voie Single Strand Annealing (SSA) indépendante de RAD51. Nos résultats ont d'abord mis en évidence un rôle inattendu de XRCC2, RAD51B et RAD51D - trois paralogues de RAD51 - dans la voie SSA. Nous avons confirmé que la fonction de la protéine XRCC2 dans la voie SSA ne dépend pas de RAD51, ce qui démontre que certains paralogues de RAD51 ont acquis des fonctions indépendantes de la recombinase. La différence de sévérité des phénotypes des mutants individuels ainsi que les analyses d'épistasie menées sur le double et le triple mutant suggèrent des fonctions individuelles de ces protéines au cours du SSA. Nous proposons qu'elles facilitent l'étape d'hybridation des deux séquences complémentaires situées de part et d'autre de la cassure, bien que ceci reste à confirmer par des études in vitro. L'étude des fonctions de l'hétérodimère XPF-ERCC1 - un complexe impliqué dans le clivage des extrémités d'ADN non homologues au cours des voies de RH - a révélé un rôle inhibiteur de ce complexe sur la voie SDSA. Cette action est dépendante de son activité endonucléasique et serait liée au clivage des longues extrémités 3' sortantes réalisant l'invasion d'un duplex d'ADN homologue, l'étape initiale de la voie SDSA. Notre étude a de plus confirmé que le rôle du complexe dépend de la longueur des extrémités non homologues chez Arabidopsis, comme chez les mammifères et la levure. Bien que le complexe XPF-ERCC1 soit essentiel au clivage des longues extrémités d'ADN non homologue, il n'est pas requis à l'élimination des courtes extrémités au cours de la RH. / The repair of DNA double-strand breaks (DSB) by recombination is essential for the maintenance of genome integrity of all living organisms. However, recombination must be finely regulated as it can generate mutations or chromosomal rearrangements, sometimes extremely deleterious to the cell. DSB can be repaired by two classes of recombination mechanism: non-homologous recombination (or DNA End Joining) or homologous recombination (implicating DNA sequence homology between the recombining molecules). In somatic cells, the two main pathways of homologous recombination (HR) are RAD51-dependent Synthesis Dependent Strand Annealing (SDSA) and RAD51-independent Single Strand Annealing (SSA). Our results have demonstrated an unexpected role of XRCC2, RAD51B and RAD51D - three RAD51 paralogues – in the SSA pathway. We confirmed that the function of XRCC2 in SSA does not depend upon RAD51, thus demonstrating that some RAD51 paralogues have acquired RAD51 recombinase-independent functions. The different severities of individual mutant phenotypes and epistasis analyses carried out on the double and triple mutants suggest individual functions of these proteins in SSA recombination. We propose that they facilitate hybridization of the two complementary sequences located on both sides of the break, although this remains to be confirmed by in vitro experiments. Study of the roles of XPF-ERCC1 - a complex involved in the cleavage of non-homologous DNA ends during HR - revealed an inhibitory role of this complex on the SDSA pathway. This is dependent on its endonuclease activity and is probably due to the cleavage of long 3' ends performing the homologous DNA duplex invasion, the initial step of the SDSA pathway. Our analyses also confirmed that the role of the complex depends on the length of the nonhomologous ends, as seen in mammals and yeasts. Although XPF-ERCC1 is essential for the cleavage of long nonhomologous DNA ends, it is not required for the elimination of short ends during HR.

Este trabalho trata da proposta de um processo de otimização para o problema do posicionamento rotacional e translacional de formas irregulares em recipientes de dimensões fixas baseado em heurísticas probabilísticas sem o uso de penalização externa. Para tanto, é empregado o polígono de obstrução, acoplado a uma heurística baseada no Recozimento Simulado. O comportamento discreto da função custo em problemas com recipientes de dimensões limitadas foi mitigado através de uma heurística de \"desempate\", que busca diferenciar soluções com valores idênticos através de uma estimativa de quão próxima está uma determinada solução de conseguir encaixar uma forma não-encaixada em seu leiaute. A comparação de resultados deste trabalho com resultados publicados na literatura comprova a validade da abordagem aqui adotada. / This work deals with the proposal of an optimization process for the packing problem with free translations and rotations of irregular shapes on containers with limited dimensions based on probabilistic heuristics without use of extern penalty techniques. For such, the no-fit polygon is used, coupled with an heuristic based on Simulated Annealing. The discrete behavior of the objective function in problems with limited containers is mitigated by a \"tie breaker\" heuristic that sorts solutions with identical values by estimating how close a given solution is of fitting an unplaced shape on its layout. The comparison of these work\'s results with results published on the literature validates the approach here adopted.

by Sau-yuen Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 77-82). / Acknowledgement --- p.i / Abstract --- p.ii / List of Tables --- p.ii / List of Figures --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Review of Previous Work --- p.4 / Chapter 2.1 --- Optimization of Delay and Layout Design --- p.4 / Chapter 2.2 --- Simulated Annealing --- p.8 / Chapter 3 --- Definition of Circuit Model --- p.12 / Chapter 4 --- Evaluation of Delay --- p.16 / Chapter 4.1 --- RC-tree and Elmore Delay --- p.16 / Chapter 4.2 --- Exponential Decayed Polynomial Function --- p.17 / Chapter 4.3 --- Two-pole Approximation --- p.18 / Chapter 4.4 --- AWE and Adopted Delay Model --- p.19 / Chapter 5 --- Delay Minimization by Simulated Annealing --- p.28 / Chapter 5.1 --- Cost Function --- p.28 / Chapter 5.2 --- Neighbor Moves --- p.30 / Chapter 5.2.1 --- Logical models --- p.31 / Chapter 5.2.2 --- Discretization of Solution Space --- p.32 / Chapter 5.2.3 --- Valid Configurations --- p.35 / Chapter 5.2.4 --- Valid Moves --- p.39 / Chapter 5.2.5 --- Modification to the Newly Generated Graph --- p.41 / Chapter 5.2.6 --- Access to Neighbor configuration --- p.43 / Chapter 5.2.7 --- Reduction of Solution Space --- p.45 / Chapter 5.2.8 --- Correctness of the Algorithm --- p.48 / Chapter 5.2.9 --- Completeness of the Algorithm --- p.49 / Chapter 6 --- Experimental result --- p.56 / Chapter 6.1 --- Optimization of Overall Performance --- p.58 / Chapter 6.2 --- Optimization on Individual Delay --- p.70 / Chapter 7 --- Conclusion --- p.74 / A --- p.76 / Bibliography

by Li Chi Pui. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves [105]-[109]). / Abstracts in English and Chinese. / Abstract / Acknowledgement --- p.Page no / Chapter Chapter 1. --- Introduction / Chapter 1.1 --- Metal silicides --- p.1 / Chapter 1.2 --- Cobalt silicides --- p.3 / Chapter 1.3 --- Ion beam synthesis of metal silicides by metal implantation into silicon --- p.4 / Chapter 1.4 --- Feature of MEVVA implantation --- p.5 / Chapter 1.5 --- Motivation and organisation of this thesis --- p.6 / Chapter Chapter 2. --- Sample Preparation and Characterisation Methods / Chapter 2.1 --- MEVVA implantation --- p.7 / Chapter 2.2 --- Simulation by TRIM --- p.9 / Chapter 2.3 --- Sample preparation --- p.12 / Chapter 2.4 --- Sheet resistivity measurements --- p.14 / Chapter 2.5 --- Rutherford backscattering spectroscopy (RBS) --- p.17 / Chapter 2.6 --- Transmission electron microscopy (TEM) --- p.19 / Chapter 2.6.1 --- Transmission electron microscopy (TEM) sample preparation --- p.21 / Chapter 2.7 --- Atom force microscopy (AFM) and conducting AFM --- p.31 / Chapter Chapter 3. --- Characterisation of As-implanted Samples / Chapter 3.1 --- Experimental details / Chapter 3.1.1 --- Sheet resistance measurements --- p.33 / Chapter 3.1.2 --- Rutherford backscattering spectroscopy (RES) --- p.36 / Chapter 3.1.3 --- Sputtering depth measurements --- p.43 / Chapter 3.1.4 --- Transmission electron microscopy (TEM) --- p.44 / Chapter 3.1.5 --- Spreading resistance profiling (SRP) --- p.61 / Chapter 3.1.6 --- Atom force microscopy (AFM) and conducting AFM --- p.64 / Chapter 3.2 --- Results and discussion --- p.71 / Chapter 3.3 --- Summary --- p.81 / Chapter Chapter 4. --- Characterisation of Annealed Samples / Chapter 4.1 --- Experimental details / Chapter 4.1.1 --- Rutherford backscattering spectroscopy (RBS) --- p.82 / Chapter 4.1.2 --- Transmission electron microscopy (TEM) --- p.87 / Chapter 4.1.3 --- Sheet resistance measurements --- p.98 / Chapter 4.2 --- Summary --- p.101 / Chapter Chapter 5. --- Conclusion --- p.102 / Appendix / Reference

Wong Yuk Chun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 71-74). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgments --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.2 / Chapter 1.2 --- The Scope of the Project --- p.2 / Chapter 1.3 --- An Outline of the Thesis --- p.3 / Chapter 2 --- Related Work --- p.5 / Chapter 2.1 --- Percolation Effect --- p.5 / Chapter 2.2 --- Percolation Models --- p.6 / Chapter 2.2.1 --- Site Percolation --- p.6 / Chapter 2.2.2 --- Bond Percolation --- p.8 / Chapter 2.3 --- Simulated Annealing --- p.8 / Chapter 3 --- Electrical Property --- p.11 / Chapter 3.1 --- Electrical Conductivity --- p.11 / Chapter 3.2 --- Physical Model --- p.13 / Chapter 3.3 --- Algorithm --- p.16 / Chapter 3.3.1 --- Simulated Annealing --- p.18 / Chapter 3.3.2 --- Neighborhood Relation and Objective Function --- p.19 / Chapter 3.3.3 --- Configuration Space --- p.21 / Chapter 3.3.4 --- Annealing Schedule --- p.22 / Chapter 3.3.5 --- Expected Time Bound --- p.23 / Chapter 3.4 --- Results --- p.26 / Chapter 3.5 --- Discussion --- p.27 / Chapter 4 --- Thermal Properties --- p.30 / Chapter 4.1 --- Thermal Expansivity --- p.31 / Chapter 4.2 --- Physical Model --- p.32 / Chapter 4.2.1 --- The Physical Properties --- p.32 / Chapter 4.2.2 --- Objective Function and Neighborhood Relation --- p.37 / Chapter 4.3 --- Algorithm --- p.38 / Chapter 4.3.1 --- Parallel Simulated Annealing --- p.39 / Chapter 4.3.2 --- The Physical Annealing Schedule --- p.42 / Chapter 4.4 --- Results --- p.43 / Chapter 4.5 --- Discussion --- p.47 / Chapter 5 --- Scaling Properties --- p.48 / Chapter 5.1 --- Problem Define --- p.49 / Chapter 5.2 --- Physical Model --- p.50 / Chapter 5.2.1 --- The Physical Properties --- p.50 / Chapter 5.2.2 --- Bond Stretching Force --- p.50 / Chapter 5.2.3 --- Objective Function and Configuration Space --- p.51 / Chapter 5.3 --- Algorithm --- p.52 / Chapter 5.3.1 --- Simulated Annealing --- p.52 / Chapter 5.3.2 --- The Conjectural Method --- p.54 / Chapter 5.3.3 --- The Physical Annealing Schedule --- p.56 / Chapter 5.4 --- Results --- p.57 / Chapter 5.4.1 --- Case I --- p.59 / Chapter 5.4.2 --- Case II --- p.60 / Chapter 5.4.3 --- Case III --- p.60 / Chapter 5.5 --- Discussion --- p.61 / Chapter 6 --- Conclusion --- p.62 / Chapter A --- An Example on Studying Electrical Resistivity --- p.64 / Chapter B --- Theory of Elasticity --- p.67 / Chapter C --- Random Number Generator --- p.69 / Bibliography

by Wong Kin Sang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 61-62). / Text in English; abstract also in Chinese. / by Wong Kin Sang. / Table of contents --- p.I / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Interest in ZnxCd1-x Se/InP --- p.1 / Chapter 1.2 --- Conditions of thermal annealing --- p.2 / Chapter 1.3 --- Advantages of using photoluminescence (PL) --- p.3 / Chapter 1.4 --- Our work --- p.4 / Chapter Chapter 2 --- Experimental setup and procedures / Chapter 2.1 --- PL measurements --- p.6 / Chapter 2.1.1 --- Setup --- p.6 / Chapter 2.1.2 --- Types of PL measurements --- p.6 / Chapter 2.2 --- Annealing experiments --- p.8 / Chapter 2.2.1 --- Setup --- p.8 / Chapter 2.2.2 --- Types of annealing --- p.10 / Chapter 2.2.3 --- Procedures --- p.11 / Chapter Chapter 3 --- Results and discussions / Chapter 3.1 --- Room temperature PL studies of ZnxCd1-xSe/InP --- p.12 / Chapter 3.1.1 --- As-grown ZnxCd1-x Se/InP --- p.12 / Chapter 3.1.1.1 --- Peak energy vs concentration --- p.12 / Chapter 3.1.2 --- Annealing studies --- p.15 / Chapter 3.1.2.1 --- Isothermal annealing --- p.15 / Chapter 3.1.2.2 --- Isochronal annealing --- p.20 / Chapter 3.2 --- PL studies of ZnxCd1-xSe/InP at 10 K temperature --- p.22 / Chapter 3.2.1 --- As-grown ZnxCd1-xSe/InP --- p.22 / Chapter 3.2.1.1 --- Excitation power density dependence --- p.22 / Chapter 3.2.1.2 --- Peak energy vs Zn concentration --- p.26 / Chapter 3.2.2 --- Annealing studies --- p.29 / Chapter 3.2.2.1 --- Isothermal annealing --- p.29 / Chapter 3.2.2.2 --- Isochronal annealing --- p.33 / Chapter 3.3 --- Temperature dependent PL studies of ZnxCd1-xSe/InP --- p.37 / Chapter 3.3.1 --- As-grown ZnxCd1-xSe/InP --- p.37 / Chapter 3.3.1.1 --- Peak energy vs temperature --- p.37 / Chapter 3.3.1.2 --- Peak width vs temperature --- p.46 / Chapter 3.3.2 --- Annealing studies --- p.50 / Chapter 3.3.1.1 --- Peak energy vs temperature --- p.50 / Chapter 3.3.1.2 --- Peak width vs temperature --- p.55 / Chapter Chapter 4 --- Conclusions --- p.59 / References --- p.61

No description available.

Les revêtements GalvAnnealed (GA), constitués de phases Fe-Zn, sont utilisés pour protéger les aciers contre la corrosion. Ces revêtements sont réalisés en trois étapes principales: le recuit de recristallisation, l'immersion dans un bain de zinc contennant de 0,11 à 0,13% poids d'aluminium et le traitement thermique du revêtement de zinc. Lors de la première étape, l'oxydation sélective des éléments d'alliage se produit à la surface de l'acier. Dans le cas des aciers chargés en éléments d'alliage (TRansformation Induced-Plasticity), les oxydes sélectifs sont connus pour créer des problèmes de réactivité entre l'acier et le zinc liquide. L'état d'oxydation sélective dépend du point de rosée (PR) de l'atmosphère de recuit. La formation du revêtement Fe-Zn implique des réactions complexes: la formation de la couche d'inhibition, sa rupture, la consommation du zinc et l'enrichissement en fer. Dans ce travail, l'effet du PR de l'atmosphère de recuit sur l'oxydation sélective et la formation du revêtement sur un acier TRIP MnAl a été étudié. Il a été montré que l'atmosphère de recuit influe principalement sur la morphologie (films ou nodules) et la localisation des oxydes par rapport à la surface de l'acier (externe / interne). Les résultats expérimentaux sont en accord avec les calculs thermodynamiques. Indépendamment du PR, la couche d'inhibition est constituée de deux phases, δ (FeZn7) et Fe2Al5Znx. Les oxydes externes formés lors du recuit sont incrustés dans ces phases. La couche d'inhibition ne bloque les réactions Fe-Zn que temporairement. Lors du traitement galvannealing, la rupture de la couche d'inhibition se produit par deux mécanismes réactionnels qui dépendent de l'état d'oxydation sélective. Globalement, les films d'oxyde (bas PR) incrustés dans la couche d'inhibition ont un effet retardateur sur les réactions Fe-Zn par rapport aux oxydes nodulaires (haut DP). / GalvAnnealed (GA) coatings, composed of Fe-Zn phases, are used to protect steels against corrosion. These coatings are produced in three main steps, namely recrystallization annealing, immersion in a zinc bath with 0.11 to 0.13 wt.% aluminum and heat treatment of the zinc coating. In the first step, the selective oxidation of the alloying elements occurs at the steel surface. In the case of high alloyed steels (e.g. TRansformation-Induced Plasticity), the selective oxides are known to be detrimental for the reactions between the steel substrate and liquid zinc. The selective oxidation state depends on the dew point (DP) of the annealing atmosphere. The coating formation involves complex reactions: the inhibition layer formation, its breakdown, the liquid zinc consumption and the iron enrichment. In this work, the effect of the DPof the annealing atmosphere on the selective oxidation and the coating formation on a TRIP MnAl steel was investigated. It was shown that the annealing atmosphere mainly affects the morphology (films or nodules) and the location of the selective oxides with respect to the steel surface (external / internal). The experimental results are in line with the thermodynamic calculations. The inhibition layer is composed of two phases, δ (FeZn7) and Fe2Al5Znx, irrespective of the DP. In addition, it contains the external oxides formed during the first step. The inhibition layer hinders the Fe-Zn reactions only temporarily. Depending on the selective oxidation state, during galvannealing treatment the inhibition layer rupture occurs by two different reaction mechanisms. Globally, the oxide films (low DP) embedded in the inhibition layer, delay the Fe-Zn reactions compared to nodular oxides (high DP).

Phase transitions and their associated critical phenomena are of fundamental importance and play a crucial role in the development of statistical physics for both classical and quantum systems. Phase transitions embody diverse aspects of physics and also have numerous applications outside physics, e.g., in chemistry, biology, and combinatorial optimization problems in computer science. Many problems can be reduced to a system consisting of a large number of interacting agents, which under some circumstances (e.g., changes of external parameters) exhibit collective behavior; this type of scenario also underlies phase transitions. The theoretical understanding of equilibrium phase transitions was put on a solid footing with the establishment of the renormalization group. In contrast, non-equilibrium phase transition are relatively less understood and currently a very active research topic. One important milestone here is the Kibble-Zurek (KZ) mechanism, which provides a useful framework for describing a system with a transition point approached through a non-equilibrium quench process. I developed two efficient Monte Carlo techniques for studying phase transitions, one is for classical phase transition and the other is for quantum phase transitions, both are under the framework of KZ scaling. For classical phase transition, I develop a non-equilibrium quench (NEQ) simulation that can completely avoid the critical slowing down problem. For quantum phase transitions, I develop a new algorithm, named quasi-adiabatic quantum Monte Carlo (QAQMC) algorithm for studying quantum quenches. I demonstrate the utility of QAQMC quantum Ising model and obtain high-precision results at the transition point, in particular showing generalized dynamic scaling in the quantum system. To further extend the methods, I study more complex systems such as spin-glasses and random graphs. The techniques allow us to investigate the problems efficiently. From the classical perspective, using the NEQ approach I verify the universality class of the 3D Ising spin-glasses. I also investigate the random 3-regular graphs in terms of both classical and quantum phase transitions. I demonstrate that under this simulation scheme, one can extract information associated with the classical and quantum spin-glass transitions without any knowledge prior to the simulation.

Computer Numerical Control (CNC) is widely used in many industries that needs high speed machining of the parts with high precision, accuracy and good surface finish. In order to avail this the generation of the CNC part program size will be immensely big and leads to an inefficient process, which increases the delivery time and cost of products. This work presents the automation of high-accuracy CNC tool trajectory planning from CAD to G-code generation through optimal NURBs surface approximation. The proposed optimization method finds the minimum number of NURBS control points for a given admissible theoretical cord error between the desired and manufactured surfaces. The result is a compact part program that is less sensitive to data starvation than circular and spline interpolations with potential better surface finish. The proposed approach is demonstrated with the tool path generation of an involute gear profile and a topologically optimized structure is developed using this approach and then finally it is 3D printed.