Hiển thị các bài đăng có nhãn density. Hiển thị tất cả bài đăng
Hiển thị các bài đăng có nhãn density. Hiển thị tất cả bài đăng

Thứ Hai, 20 tháng 4, 2015

Material Designs and New Physical Properties in MX- and MMX-Chain Compounds

Material Designs and New Physical Properties in MX- and MMX-Chain Compounds



This is the first book to comprehensively address the recent developments in both the experimental and theoretical aspects of quasi-one-dimensional halogen-bridged mono- (MX) and binuclear metal (MMX) chain complexes of Pt, Pd and Ni. These complexes have one-dimensional electronic structures, which cause the various physical properties as well as electronic structures. In most MX-chain complexes, the Pt and Pd units are in M(II)-M(IV) mixed valence or charge density wave (CDW) states due to electron-phonon interactions, and Ni compounds are in Ni(III) averaged valence or Mott-Hubbard states due to the on-site Coulomb repulsion. More recently, Pd(III) Mott-Hubbard (MH) states have been realized in the ground state by using the chemical pressure. Pt and Pd chain complexes undergo photo-induced phase transitions from CDW to MH or metal states, and Ni chain complexes undergo photo-induced phase transitions from MH to metal states. Ni chain complexes with strong electron correlations show tremendous third-order optical nonlinearity and nonlinear electrical conductivities. They can be explained theoretically by using the extended Peierls-Hubbard model. For MMX-chain complexes, averaged valence, CDW, charge polarization, and alternating charge polarization states have been realized by using chemical modification and external stimuli, such as temperature, photo-irradiation, pressure, and water vapor. All of the electronic structures and phase transitions can be explained theoretically.




Chủ Nhật, 1 tháng 3, 2015

Visualization of Hydrogen-Bond Dynamics

Visualization of Hydrogen-Bond Dynamics



The hydrogen bond represents an important interaction between molecules, and the dynamics of hydrogen bonds in water create an ever-present question associated with the process of chemical and biological reactions. In spite of numerous studies, the process remains poorly understood at the microscopic level because hydrogen-bond dynamics, such as bond rearrangements and hydrogen/proton transfer reactions, are extremely difficult to probe. Those studies have been carried out by means of spectroscopic methods where the signal stems from the ensemble of a system and the hydrogen-bond dynamics were inferred indirectly. This book addresses the direct imaging of hydrogen-bond dynamics within water-based model systems assembled on a metal surface, using a scanning tunneling microscope (STM). The dynamics of individual hydrogen bonds in water clusters, hydroxyl clusters, and water-hydroxyl complexes are investigated in conjunction with density functional theory. In these model systems, quantum dynamics of hydrogen bonds, such as tunneling and zero-point nuclear motion, are observed in real space. Most notably, hydrogen atom relay reactions, which are frequently invoked across many fields of chemistry, are visualized and controlled by STM. This work presents a means of studying hydrogen-bond dynamics at the single-molecule level, providing an important contribution to wide fields beyond surface chemistry.




Thứ Hai, 23 tháng 2, 2015

FEFLOW

FEFLOW



FEFLOW is an acronym of Finite Element subsurface FLOW simulation system and solves the governing flow, mass and heat transport equations in porous and fractured media by a multidimensional finite element method for complex geometric and parametric situations including variable fluid density, variable saturation, free surface(s), multispecies reaction kinetics, non-isothermal flow and multidiffusive effects. FEFLOW comprises theoretical work, modeling experiences and simulation practice from a period of about 40 years. In this light, the main objective of the present book is to share this achieved level of modeling with all required details of the physical and numerical background with the reader. The book is intended to put advanced theoretical and numerical methods into the hands of modeling practitioners and scientists. It starts with a more general theory for all relevant flow and transport phenomena on the basis of the continuum approach, systematically develops the basic framework for important classes of problems (e.g., multiphase/multispecies non-isothermal flow and transport phenomena, discrete features, aquifer-averaged equations, geothermal processes), introduces finite-element techniques for solving the basic balance equations, in detail discusses advanced numerical algorithms for the resulting nonlinear and linear problems and completes with a number of benchmarks, applications and exercises to illustrate the different types of problems and ways to tackle them successfully (e.g., flow and seepage problems, unsaturated-saturated flow, advective-diffusion transport, saltwater intrusion, geothermal and thermohaline flow).




Thứ Hai, 19 tháng 1, 2015

Advanced Methods of Fatigue Assessments

Advanced Methods of Fatigue Assessments



In five chapters, this volume presents recent developments in fatigue assessment. In the first chapter, a generalized Neuber concept of fictitious notch rounding is presented where the microstructural support factors depend on the notch opening angle besides the loading mode. The second chapter specifies the notch stress factor including the strain energy density and J-integral concept while the SED approach is applied to common fillet welded joints and to thin-sheet lap welded joints in the third chapter. The forth chapter analyses elastic-plastic deformations in the near crack tip zone and discusses driving force parameters. The last chapter discusses thermomechanical fatigue, stress, and strain ranges.




Thứ Bảy, 17 tháng 1, 2015

Quasicrystals

Quasicrystals



The book provides an introduction to all aspects of the physics of quasicrystals. The chapters, each written by an expert in this field, cover quasiperiodic tilings and the modeling of the atomic structure of quasicrystals. The electronic density of states and the calculation of the electronic structure play a key role in this introduction, as does an extensive discussion of the atomic dynamics. The study of defects in quasicrystals by high resolution electron microscopy and the computer simulations of defects and fracture in decorated tilings are important subjects for the application of these aperiodic crystals.




Thứ Ba, 30 tháng 12, 2014

Handbook of VLSI Microlithography

Handbook of VLSI Microlithography



This handbook gives readers a close look at the entire technology of printing very high resolution and high density integrated circuit (IC) patterns into thin resist process transfer coatings– including optical lithography, electron beam, ion beam, and x-ray lithography. The book’s main theme is the special printing process needed to achieve volume high density IC chip production, especially in the Dynamic Random Access Memory (DRAM) industry.