다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

This is a review of Collected Works of John Tate. Parts I, II, edited by Barry Mazur and Jean-Pierre Serre. American Mathematical Society, Providence, Rhode Island, 2016. For several decades it has been clear to the friends and colleagues of John Tate that a “Collected Works” was merited. The award of the Abel Prize to Tate in 2010 added impetus, and finally, in Tate’s ninety-second year we have these two magnificent volumes, edited by Barry Mazur and Jean-Pierre Serre. Beyond Tate’s published articles, they include five unpublished articles and a selection of his letters, most accompanied by Tate’s comments, and a collection of photographs of Tate. For an overview of Tate’s work, the editors refer the reader to [4]. Before discussing the volumes, I describe some of Tate’s work. 1. Hecke L-series and Tate’s thesis Like many budding number theorists, Tate’s favorite theorem when young was Gauss’s law of quadratic reciprocity. When he arrived at Princeton as a graduate student in 1946, he was fortunate to find there the person, Emil Artin, who had discovered the most general reciprocity law, so solving Hilbert’s ninth problem. By 1920, the German school of algebraic number theorists (Hilbert, Weber, . . .) together with its brilliant student Takagi had succeeded in classifying the abelian extensions of a number field K: to each group I of ideal classes in K, there is attached an extension L of K (the class field of I); the group I determines the arithmetic of the extension L/K, and the Galois group of L/K is isomorphic to I. Artin’s contribution was to prove (in 1927) that there is a natural isomorphism from I to the Galois group of L/K. When the base field contains an appropriate root of 1, Artin’s isomorphism gives a reciprocity law, and all possible reciprocity laws arise this way. In the 1930s, Chevalley reworked abelian class field theory. In particular, he replaced “ideals” with his “idèles” which greatly clarified the relation between the local and global aspects of the theory. For his thesis, Artin suggested that Tate do the same for Hecke L-series. When Hecke proved that the abelian L-functions of number fields (generalizations of Dirichlet’s L-functions) have an analytic continuation throughout the plane with a functional equation of the expected type, he saw that his methods applied even to a new kind of L-function, now named after him. Once Tate had developed his harmonic analysis of local fields and of the idèle group, he was able prove analytic continuation and functional equations for all the relevant L-series without Hecke’s complicated theta-formulas. Received by the editors September 5, 2016. 2010 Mathematics Subject Classification. Primary 01A75, 11-06, 14-06. c ©2017 American Mathematical Society

The collected works

Liquid phase sintering (LPS) is a process for forming high performance, multiple-phase components from powders. It involves sintering under conditions where solid grains coexist with a wetting liquid. Many variants of LPS are applied to a wide range of engineering materials. Example applications for this technology are found in automobile engine connecting rods and high-speed metal cutting inserts. Scientific advances in understanding LPS began in the 1950s. The resulting quantitative process models are now embedded in computer simulations to enable predictions of the sintered component dimensions, microstructure, and properties. However, there are remaining areas in need of research attention. This LPS review, based on over 2,500 publications, outlines what happens when mixed powders are heated to the LPS temperature, with a focus on the densification and microstructure evolution events.

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Review: liquid phase sintering

Grain refinement of aluminium and its alloys is common industrial practice. The field has been extensively investigated by many workers over the past 50 years, not only to develop efficient grain refiners for different aluminium alloys, but also to achieve an understanding of the mechanism of grain refinement. The present review confines itself to the literature on grain refinement by heterogeneous nucleation and alloying. Initially, the fundamentals of grain refinement by inoculants are outlined. The types of grain refiner, Al-Ti-B master alloys in particular, and their methods of manufacture are next discussed. The grain refining tests to assess the efficiency of the grain refiners and the grain refining behaviour of aluminium alloys are also discussed in brief. The performance of a grain refiner, as well as the response of an aluminium alloy to grain refinement, is influenced by the microstructure of the grain refiner as controlled by the process parameters involved in its preparation and the alloying elements present in the aluminium alloy. The roles of these factors, and particularly the roles of poisoning elements such as Si, Cr, Zr, Li, are reviewed. The paper also reviews the mechanisms of grain refinement, the fading and poisoning phenomena, and the trends in the development of new grain refiners for aluminium alloys containing poisoning elements.

Grain refinement of aluminium and its alloys by heterogeneous nucleation and alloying

The superalloy INCONEL 718 (IN718) is a commonly used material in aerospace and turbine components. The advantage of this type of material with sluggish precipitation-hardening kinetics is that IN718 is readily weldable. Both wrought and cast parts are used and welded together. While the alloy has been studied previously, new production processes such as laser treatment demand better knowledge of the solidification process in IN718, especially at high cooling rates. In this investigation, the solidification process was studied over a wide range of cooling rates by three different experimental techniques: differential thermal analysis (DTA), mirror furnace (MF), and levitation casting. The solidification sequence and the reaction temperatures were identified. The microstructure and the change in growth morphology were also studied. Segregation measurements were performed, and the distribution of Nb was analyzed in detail for the different types of samples, because of its strong impact on the solidification sequence and microstructure. New observations are that the latent heat decreases and the effective partition coefficient increases with increasing cooling rate. The diffusion rate also seems to be enhanced in the first part of primary solidified dendrites. It is suggested that the new observations can be explained by an increased number of lattice defects formed in the solid as the cooling rate increases.

The effect of cooling rate on the solidification of INCONEL 718

Preface Chapter 1 Thermodynamic Concepts and Relationships 1.1 Introduction 1.2 Thermodynamic Concepts and Relationships 1.3 Thermodynamics of Single Component Systems 1.4. Thermodynamics of Multiple Component Systems 1.5 Thermodynamics of Alloys 1.6 Thermodynamics of Ideal Binary Solutions 1.7 Thermodynamics of Non-Ideal Binary Solutions 1.8 Experimental Determination of Thermodynamic Quantities of Binary Alloys Summary Chapter 2 Thermodynamics Analysis of Solidification Processes in Metals and Alloys 2.1 Introduction 2.2 Thermodynamics of Pure Metals 2.3 Thermodynamics of Binary Alloys 2.4 Equilibrium between Phases in Binary Solutions. Phase Diagrams of Binary Alloys 2.5 Driving Force of Solidification in Binary Alloys 2.6 Thermodynamics of Ternary Alloys 2.7 Thermodynamics of Vacancies in Pure Metals and Alloys Summary Exercises References Chapter 3 Properties of Interfaces 3.1 Introduction 3.2 Classical Theory of Interface Energy and Surface Tension 3.3 Thermodynamics of Interfaces 3.4 Structures of Interfaces 3.5 Equilibrium Shapes of Crystals Summary Exercises References Chapter 4 Nucleation 4.1 Introduction 4.2 Homogeneous Nucleation 4.3 Heterogeneous Nucleation. Inoculation 4.4 Nucleation of Bubbles 4.5 Crystal Multiplication Summary Exercises References Chapter 5 Crystal Growth in Vapours 5.1 Introduction 5.2 Crystal Morphologies 5.3 Chemical Vapour Deposition 5.4 Crystal Growth 5.5 Normal Crystal Growth of Rough Surfaces in Vapours 5.6 Layer Crystal Growth of Smooth Surfaces in Vapours 5.7 Influence of Impurities on Crystal Growth in Vapours 5.8 Epitaxial Growth 5.9 Whisker Growth 5.10 Mechanical Restrictions on Thin Films Summary Exercises References Chapter 6 Crystal Growth in Liquids and Melts 6.1 Introduction 6.2 Structures of Crystals and Melts 6.3 Growth Methods 6.4 Crystal Growth 6.5 Volume Changes and Relaxation Processes during Anelastic Crystal Growth in Metal Melts 6.6 Normal Crystal Growth in Pure Metal Melts 6.7 Layer Crystal Growth of Smooth Surfaces in Liquids 6.8 Normal Crystal Growth in Binary Alloys 6.9 Diffusion Controlled Growth of Planar Crystals in Binary Alloys 6.10 Diffusion Controlled Growth of Spherical Crystals in Alloys 6.11 Impingement 6.12 Precipitation of Pores Summary Exercises References Chapter 7 Heat Transport during Solidification Processes.Thermal Analysis 7.1 Introduction 7.2 Basic Concepts and Laws of Heat Transport 7.3 Convection 7.4 Theory of Heat Transport at Unidirectional Solidification 7.5 Production of Single Crystals by Unidirectional Solidification 7.6 Thermal Analysis 7.7 Variable Heat of Fusion of Metals and Alloys 7.8 Variable Heat Capacitivity of Metals and Alloys Summary Exercises References Chapter 8 Crystal Growth Controlled by Heat and Mass Transport 8.1 Introduction 8.2 Heat and Mass Transports in Alloys during Unidirectional Solidification 8.3 Zone Refining 8.4 Single Crystal Production by Czochralski Technique 8.5 Cellular Growth. Constitutional Undercooling. Interface Stability Summary Exercises References Chapter 9 Faceted and Dendritic Solidification Structures 9.1 Introduction 9.2 Formation of Faceted Crystals 9.3 Growth of Faceted Crystals in Pure Metal Melts 9.4 Growth of Faceted Crystals in Alloy Melts 9.5 Growth of Dendritic Crystals 9.6 Development of Dendrites 9.7 Transitions between Structure Types in Alloys Summary Exercises References Chapter 10 Eutectic Solidification Structures 10.1 Introduction 10.2 Classification of Eutectic Structures 10.3 Normal Eutectic Growth 10.4 Degenerate and Coupled Eutectic Growth 10.5 Structures of Ternary Alloys 10.6 Solidification of Fe-C Eutectics 10.7 Solidification of Al-Si Eutectics 10.8 Transitions between Normal Lamellar and Rod Eutectic Growths Summary Exercises References Chapter 11 Peritectic Solidification Structures 11.1 Introduction 11.2 Peritectic Reactions and Transformations 11.3 Peritectic Reactions and Transformations in Iron-Base Alloys 11.4 Metastable Reactions in Iron-Base Alloys 11.5 Metatectic Reactions and Transformations 11.6 Microsegregation in Iron-Base Alloys 11.7 Transition between Peritectic and Eutectic Reactions in in Iron-Base Alloys Summary Exercises References Chapter 12 Metallic Glasses and Amorphous Alloy Melts 12.1 Introduction 12.1 History and Development of Amorphous Alloys 12.2 Basic Concepts and Definitions 12.3 Production of Metallic Glasses 12.4 Experimental Methods for Structure Determination of Metallic Glasses and Amorphous Alloy Melts 12.5 Structure of Metallic Glasses 12.6 Comparison of the Structures of Metallic Glasses and Amorphous Alloy Melts. Rough Model of Metallic Glasses and Amorphous Alloy Melts 12.7 Casting of Metallic Glasses. Crystallization Processes in Amorphous Alloy Melts 12.8 Classification of Metallic Glasses 12.9 Properties and Applications of Metallic Glasses Summary Exercises References Answers to Exercises Index

Solidification and Crystallization Processing in Metals and Alloys

The energetic chemical and structural properties of interfaces between solid and liquid metals are of great interest in numerous applications. However, solid-liquid interfacial energies of metals a ...

Correlations between Surface and Interface Energies with Respect to Crystal Nucleation

Preface. Chapter 1: Component Casting. 1.1 Introduction. 1.2 Casting of Components. Chapter 2: Cast House Processes. 2.1 Introduction. 2.2 Ingot Casting. 2.3 Continuous Casting. 2.4 From Ladle to Chill-mould in Continuous Casting of Steel. 2.5 Near Net Shape Casting. 2.6 The ESR Process. Chapter 3 Casting Hydrodynamics. 3.1 Introduction. 3.2 Basic Hydrodynamics. 3.3 Gating Systems in Component Casting. 3.4 Gating System in Ingot Casting. 3.5 Gating System in Continuous Casting. 3.6 Inclusion Control in Gating Systems - Ceramic Filters. 3.7 Maximum Fluidity Length. Summary. Exercises. Chapter 4: Heat Transport during Component Casting. 4.1 Introduction. 4.2 Basic Concepts and Laws of Heat Transport. 4.3 Theory of Heat Transport in Casting of Metals and Alloys. 4.4 Heat Transport in Component Casting. Summary. Exercises. Chapter 5: Heat Transport in Cast House Processes. 5.1 Introduction. 5.2 Natural Convection in Metal Melts. 5.3 Heat Transport in Ingot Casting. 5.4 Water Cooling. 5.5 Heat Transport during Continuous Casting of Steel. 5.6 Heat Transport in the ESR Process. 5.7 Heat Transport in Near Net Shape Casting. 5.8 Heat Transport in Spray Casting. Summary. Exercises. Chapter 6: Structure and Structure Formation in Cast Materials. 6.1 Introduction. 6.2 Structure Formation in Cast Materials. 6.3 Dendrite Structure and Dendrite Growth. 6.4 Eutectic Structure and Eutectic Growth. 6.5 Cooling Curves and Structure. 6.6 Unidirectional Solidification. 6.7 Macrostructures in Cast Materials. 6.8 Macrostructures in Ingot Cast Materials. 6.9 Macrostructures in Continuously Cast Materials. 6.10 Macrostructures in Near Net Shape Cast Materials. 6.11 Amorphous Metals. Summary. Exercises. Chapter 7: Microsegregation in Alloys - Peritectic Reactions and Transformations. 7.1 Introduction. 7.2 Cooling Curves, Dendritic Growth, and Microsegregation. 7.3 Scheil's Segregation Equation - a Model of Microsegregation. 7.4 Solidification Processes in Alloys. 7.5 Influence of Back Diffusion in the Solid Phase on Microsegregation of Alloys. 7.6 Solidification Processes and Microsegregation in Iron-base Alloys. 7.7 Peritectic Reactions and Transformations in Binary Iron-base Alloys. 7.8 Microsegregation in Multicomponent Alloys. 7.9 Microsegregation and Peritectic Reactions and Transformations in Multicomponent Iron-base Alloys. Summary. Exercises. Chapter 8: Heat Treatment and Plastic Forming. 8.1 Introduction. 8.2 Homogenization. 8.3 Dissolution of Secondary Phases. 8.4 Change of Casting Structure During Cooling and Plastic Deformation. 8.5 Cooling Shrinkage and Stress Relief Heat Treatment. 8.6 Hot Isostatic Pressing. Summary. Exercises. Chapter 9: Precipitation of Pores and Slag Inclusions during Casting Processes. 9.1 Introduction. 9.2 Units and Laws. 9.3 Precipitation of Gases in Metal Melts. 9.4 Precipitation of Inclusions in Metal Melts. 9.5 Aluminium and Aluminium Alloys. 9.6 Copper and Copper Alloys. 9.7 Steel and Iron Alloys. 9.8 Cast Iron. 9.9 Nickel and Nickel-Base Alloys. Summary. Exercises. Chapter 10: Solidification and Cooling Shrinkage of Metals and Alloys. 10.1 Introduction. 10.2 Solidification and Cooling Shrinkage. 10.3 Concepts and Laws. Methods of Measurement. 10.4 Solidification and Cooling Shrinkage during Casting. 10.5 Solidification Shrinkage during Ingot Casting. 10.6 Solidification and Cooling Shrinkage during Continuous Casting. 10.7 Thermal Stress and Crack Formation during Solidification and Cooling Processes. Summary. Exercises. Chapter 11: Macrosegregation in Alloys. 11.1 Introduction. 11.2 Macrosegregation due to Solidification Shrinkage. 11.3 Macrosegregation during Unidirectional Solidification. 11.4 Inverse Macrosegregation. 11.5 Macrosegregation during Continuous Casting. 11.6 Centre Segregation during Continuous Casting. 11.7 Freckles. 11.8 Macrosegregation during Horizontal Solidification. 11.9 Macrosegregations in Steel Ingots. Summary. Exercises. Answers to Exercises. Index.

Materials processing during casting

The directional solidification technique was applied in order to investigate the complicated solidification sequence in a commercial austenitic stainless steel which was known to yield a primary precipitation of § ferrite when cast into a 5 tons ingot. Three stages of solidification were found. The first precipitation of § ferrite was interrupted by precipitation of austenite and at the end of the solidification there was a transition back to precipitation of § ferrite. The competition between the first two stages is affected by the cooling rate and the nitrogen content. The precipitation of austenite from the melt results in the usual coring whereas o ferrite forms with a very homogeneous composition, presumably due to rapid diffusion in this phase. On cooling austenite forms from the § ferrite and this reaction also results in coring, presumably due to rapid diffusion in § ferrite.

Hasse Fredriksson

Papers

The effect of cooling rate on the solidification of INCONEL 718

Solidification and Crystallization Processing in Metals and Alloys

Correlations between Surface and Interface Energies with Respect to Crystal Nucleation

Materials processing during casting

The solidification sequence in an 18-8 stainless steel, investigated by directional solidification