A Rationalization of Sympathetic Nucleation-Ledgewise Growth Theory of Bainite Transformation in Fe-C Alloys

Based on the classic diffusion controlled nucleation and goth theory, the sympathatic nucleation- ledgewise growth mechanism of bainite was studied theoretically for low carbon Fe-C alloys. The rationality of the occurrence of sympathetic nucleation on the terraces of ledges compating with lateral ledge growth and other sites nucleation was demonstrated by the present work quantita- tively The calculations indicated that low reaction temperatures and high carbon concentrations may favor the sympathetic nucleation, thus accounting for the formation of multilayer structures of bainite.

Multisphere Tectonics of the Earth System

The fundamental theoretical framework of the Multisphere Tectonics of the Earth System is as follows:(1)It intends to extend the geotectonic studies from the crustal and lithospheric tectonics to the multisphere tectonics of the Ear th system as a whole.(2)The global dynamics driven by both the Earth system and the cosmic celestial system:solar energy,multispheric interactions of the Earth system and the combined effects of the motions of celestial bodies in the cosmos syste m are the driving forces of various geological processes.(3)The Continent-Ocean transformation theory:the continent and ocean are two opposite yet unified geological units,which can be transformed into each other;neither continent nor ocean wi ll survive forever;there is no one-way development of continental accretion or ocean extinction;the simple theory of one-way continental accretion is regarded as invalid.(4)The continental crust and mantle are characterized by multiple layers,with different layers liable to slide along the interfaces between them,but corroboration is needed that continents move as a who le or even drift freely.(5)The cyclic evolution theory:the development of Earth’s tectonics is not a uniform change,but a spiral forward evolution,characterized by a combination of non-uniform,non-linear,gradual and catastrophic changes;different evolutionary stages(tectonic cycles)of Earth have distinctive global tectonic patterns and characteristics,one tectonic mo del should not be applied to different tectonic cycles or evolutionary stages.(6)The structure and evolution of Earth are asymmetric and heterogeneous,thus one tectonic model cannot be applied to different areas of the world.(7)The polycyclic evolution of the continental crust:the continental crust is formed by polycyclic tectonics and magmatism,rather than simply lateral or vertical accretion.(8)The role of deep faults:the deep fault zones cutting through different layers of the crus t a nd mantle usually play important roles in tectonic evolution.For example,the present-day mid-ocean ridge fault zones,transform fault zones and Benioff zones outline the global tectonic framework.Different tectonic cycles and stages of Earth’s evolutio n must have their own distinctive deep fault systems which control the global tectonic framework and evolutionary processes during different tectonic cycles and stages.Starting from the two mantle superplumes Jason(Pacific)and Tuzo(Africa),the study of the evolutionary process of the composition and structure of the crust and mantle during the great transformation an d reorganization of the Meso-Cenozoic tectonic framework in China and the other regions of Asia is a good demonstration of theory of Multisphere Tectonics of the Earth System.

Rough singular integrals associated with surfaces of Van der Corput type

In this paper, the authors establish the LV-mapping properties for a class of singular integrals along surfaces in Rn of the form {Ф（lul）u＇ ： u ε ]t^n} as well as the related maimal operators provided that the function Ф satisfies certain oscillatory integral estimates of Van der Corput type, and the integral kernels are given by the radial function h E ε△γ（R＋） for γ 〉 1 and the sphere function ΩεFβ（S^n-1） for someβ 〉 0 which is distinct from HI（Sn-1）.