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Books > Science & Mathematics > Physics > Applied physics & special topics
This book on pressure-induced phase transitions in AB2X4 chalcogenide compounds deals with one important AmBnXp material. The interest in these materials is caused by their properties. The results are discussed for three main groups of structural families: cubic-spinel structures, defective tetragonal structures, and other structures like layered and wurtzite-type modifications. A systematic analysis of the behavior of cubic (spinel), tetragonal (defect chalcopyrites and stannites) and other crystal modifications of AB2X4 compounds under hydrostatic pressure is performed. The behavior of AIIAl2S4, AIIGa2S4, AIIAl2Se4 and AIIGa2Se4 compounds with defective tetragonal structures, compounds with layered and wurtzite structures under hydrostatic pressure and the pressure dependence of the band gap, lattice parameters, interatomic distances, vibrational modes and pressure-induced phase transitions is discussed. Many of these compounds, except oxide spinels, undergo a pressure-induced phase transition towards the rocksalt-type structure. The phase transition is preceded by disorder in the cation sublattice. The dependence of the transition pressure to the rocksalt-type structure as a function of the compound ionicity and the size criterion is analyzed. At high pressures, all ordered-vacancy compounds are found to exhibit a band anticrossing between several conduction bands that leads to a strong decrease of its pressure coefficient and consequently to a strong non-linear pressure dependence of the direct bandgap energy. Theoretical studies of phase transitions in several ordered-vacancy compounds reveal that the existence of ordered vacancies alter the cation-anion bond distances and their compressibilities. The book is written for students, Ph D. students and specialists in materials science, phase transitions and new materials.
"Mechanobiology of Cell-Matrix Interactions" focuses on characterization and modeling of interactions between cells and their local extracellular environment, exploring how these interactions may mediate cell behavior. Studies of cell-matrix interactions rely on integrating engineering, (molecular and cellular) biology, and imaging disciplines. Recent advances in the field have begun to unravel our understanding of how cells gather information from their surrounding environment, and how they interrogate such information during the cell fate decision making process. Topics include adhesive and integrin-ligand interactions; extracellular influences on cell biology and behavior; cooperative mechanisms of cell-cell and cell-matrix interactions; the mechanobiology of pathological processes; (multi-scale) modeling approaches to describe the complexity or cell-matrix interactions; and quantitative methods required for such experimental and modeling studies.
This thesis describes an in-depth study of an indolizine-based fluorophore, from understanding of its structure-photophysical property relationship to its application as a useful biological reporter. Organic fluorophores have been extensively used in the field of molecular biology owing to their excellent photophysical property, suitable cell permeability, and synthetic flexibility. Understanding of the structure-photophysical property relationship of a given fluorophore often paves the road to the development of valuable molecular probes to visualize and transcribe biological networks. In this thesis, respective chapters deal with molecular design, organic synthesis, structure-property analysis, and quantum-mechanical interpretation of unexplored family of indolizine-based molecules. This systematic exploration has led to rational development of a new microalgae lipid droplet probe, colorful bioorthogonal fluorogenic probes, and a bright mitochondrial probe, working under live cell conditions. Harnessing the optical properties of a given fluorophore has been an important topic for a couple of decades, both in industry and in academia. This thesis provides useful insights for the improvement and development of unique small fluorescent materials, or optical materials.
It all began with Markus Jochum approaching one of us (HvS) - "when you guys are doing interviews with senior scientists from oceanography and related sciences, why are you not doing Walter Munk?" Indeed, why not? Walter Munk, an icon in oceanography, had just given a wonderful talk in a symposium in honor of his 90th birthday, sweeping a grand circle from his earliest work with Chip Cox on airborne measurements of ocean surface roughness to the latest satellite data - not simply a review, but the struggle of an active scientist opening up new perspectives - as inspiring and stimulating as when one of us (KH) rst met him at the Ocean Waves Conference in Easton in 1961 (Fig. I. 1). Walter immediately agreed to share with us his recollections on the nearly seventy years of his path-breaking contributions in a sheer amazing range of topics, from ocean waves, internal waves, ocean currents, tides, tsunamis, sea level, microseisms and the rotation of the earth to ocean acoustic tomography. With "you guys" Markus was referring to HvS and the various partners HvS had 1 invited to join him in conducting a series of interviews of retired colleagues.
Driven in part by the development of genomics, proteomics, and
bioinformatics as new disciplines, there has been a tremendous
resurgence of interest in physical methods to investigate
macromolecular structure and function in the context of living
cells. This volume in "Methods in Cell Biology" is devoted to
biophysical techniques "in vivo" and their applications to cellular
biology. The volume covers methods-oriented chapters on fundamental
as well as cutting-edge techniques in molecular and cellular
biophysics. This book is directed toward the broad audience of cell
biologists, biophysicists, pharmacologists, and molecular
biologists who employ classical and modern biophysical technologies
or wish to expand their expertise to include such approaches. It
will also interest the biomedical and biotechnology communities for
biophysical characterization of drug formulations prior to FDA
approval.
Astronomical jets are key astrophysical phenomena observed in gamma-ray bursts, active galactic nuclei or young stars. Research on them has largely occurred within the domains of astronomical observations, astrophysical modeling and numerical simulations, but the recent advent of high energy density facilities has added experimental control to jet studies. Front-line research on jet launching and collimation requires a highly interdisciplinary approach and an elevated level of sophistication. Bridging the gaps between pure magnetohydrodynamics, thermo-chemical evolution, high angular resolution spectro-imaging and laboratory experiments is no small matter. This volume strives to bridge those very gaps. It offers a series of lectures which, taken as whole, act as a thorough reference for the foundations of this discipline. These lectures address the following: - laboratory jets physics from laser and z-pinch plasma
experiments, In addition to the lectures, the book offers, in closing, a
presentation of a series of observational diagnostics, thus
allowing for the recovery of basic physical quantities from jet
emission lines.
This book covers topics on mechanosensing, mechanotransduction, and actin cytoskeletal dynamics in cell motility. It will contribute to a better understanding of how cells functionally adapt to their mechanical environment as well as highlighting fundamental concepts for designing material niches for cell manipulation. With topics from multidisciplinary fields of the life sciences, medicine and engineering, the book is the first of its kind, providing comprehensive, integrated coverage of innovative approaches to cell biomechanics. It provides a valuable resource for seniors and graduate students studying cell biomechanics and is also suitable for researchers interested in the application of methods and strategies in connection with the innovative approaches discussed. Each section of the book has been supplemented with concrete examples and illustrations to facilitate understanding even for readers unfamiliar with cell biomechanics.
This thesis sheds new light on the worldwide first electrical manipulation of a single nuclear spin. Over the last four decades, the size of a bit, the smallest logical unit in a computer, has decreased by more than two orders of magnitude and will soon reach a limit where quantum phenomena become important. Inspired by the power of quantum mechanics, researchers have already identified pure quantum systems, having, analog to a classical bit, two controllable and readable states. In this regard, the inherent spin of electrons or nuclei with its two eigenstates, spin up and spin down, is a promising candidate. Using expertise in the field of single-molecule magnets, the author developed a molecular transistor, which allows quantum information to be written onto a single nuclear spin by means of an electric field only, and, in addition, enables the electronic read-out of this quantum state. This novel approach opens a path to addressing and manipulating individual nuclear spins within a very confined space (a single molecule), at high speed. Thus, the author was able to show that single molecule magnets are promising candidates for quantum information processing, which is triggering a new field of research towards molecular quantum electronics.
This volume is a collection of articles from the ISSBMR 7th Course: Structure and Biophysics - New Technologies for Current Challenges in Biology and Beyond. This NATO Advanced Institute (ASI) was held at the Ettore Majorana Foundation and Centre for Scientific Culture in Sicily. The ASI brought together a diverse group of experts in the fields of Structural Biology, Biophysics and Physics. Prominent lecturers, from seven different countries, and students from around the world participated. The session addressed the treatment and detection of bioterrorism agents, and focused on critical partner country priorities in biotechnology, materials and drug discovery. The range of topics represents the diversity of critical problems between structural biology, biochemistry and biophysics, in which lies the fertile ground of drug development, biotechnology and new materials.
This book provides an introduction to the physics of interstellar gas in the Galaxy. It deals with the diffuse interstellar medium which supplies a complex environment for exploring the neutral gas content of a galaxy like the Milky Way and the techniques necessary for studying this non-stellar component. After an initial exposition of the phases of the interstellar medium and the role of gas in a spiral galaxy, the authors discuss the transition from atomic to molecular gas. They then consider basic radiative transfer and molecular spectroscopy with particular emphasis on the molecules useful for studying low-density molecular gas. Observational techniques for investigating the gas and the dust component of the diffuse interstellar medium throughout the electromagnetic spectrum are explored emphasizing results from the recent Herschel and Planck missions. A brief exposition on dust in the diffuse interstellar medium is followed by a discussion of molecular clouds in general and high-latitude molecular clouds in particular. Ways of calibrating CO observations with the molecular hydrogen content of a cloud are examined along with the dark molecular gas controversy. High-latitude molecular clouds are considered in detail as vehicles for applying the techniques developed in the book. Given the transient nature of diffuse and translucent molecular clouds, the role of turbulence in the origin and dynamics of these objects is examined in some detail. The book is targeted at graduate students or postdocs who are entering the field of interstellar medium studies.
This interdisciplinary thesis introduces a systems biology approach to study the cell fate decision mediated by autophagy. A mathematical model of interaction between Autophagy and Apoptosis in mammalian cells is proposed. In this dynamic model autophagy acts as a gradual response to stress (Rheostat) that delays the initiation of bistable switch of apoptosis to give the cells an opportunity to survive. The author shows that his dynamical model is consistent with existing quantitative measurements of time courses of autophagic responses to cisplatin treatment. To understand the function of this response in cancer cells, he has provided a systems biology experimental framework to study quantitative and dynamical aspects of autophagy in single cancer cells using live-cell imaging and quantitative fluorescence microscopy. This framework can provide new insights on function of autophagic response in cancer cells.
This book on multiscale seismic tomography, written by one of the leaders in the field, is suitable for undergraduate and graduate students, researchers, and professionals in Earth and planetary sciences who need to broaden their horizons about seismotectonics, volcanism, and interior structure and dynamics of the Earth and Moon. It describes the state-of-the-art in seismic tomography, with emphasis on the new findings obtained by applying tomographic methods in local, regional, and global scales for understanding the generating mechanism of large and great earthquakes such as the 2011 Tohoku-oki earthquake (Mw 9.0), crustal and upper mantle structure, origin of active arc volcanoes and intraplate volcanoes including hotspots, heterogeneous structure of subduction zones, fate of subducting slabs, origin of mantle plumes, mantle convection, and deep Earth dynamics. The first lunar tomography and its implications for the mechanism of deep moonquakes and lunar evolution are also introduced.
This thesis makes two important contributions to plasma physics. The first is the extension of the seminal theoretical works of Spitzer and Braginskii, which describe the basics of particle interactions in plasma, to relativistic systems. Relativistic plasmas have long been studied in high-energy astrophysics and are becoming increasingly attainable in the laboratory. The second is the design of a new class of photon-photon collider, which is the first capable of detecting the Breit-Wheeler process. Though it offers the simplest way for light to be converted into matter, the process has never been detected in the 80 years since its theoretical prediction. The experimental scheme proposed here exploits the radiation used in inertial confinement fusion experiments and could in principle be implemented in one of several current-generation facilities.
A complete solution for problems of vibration control in structures that may be subject to a broadband primary vibration field, this book addresses the following steps: experimental identification of the dynamic model of the structure; optimal placement of sensors and actuators; formulation of control constraints in terms of controller frequency response shape; controller design and simulation; and controller implementation and rapid prototyping. The identification procedure is a gray-box approach tailored to the estimation of modal parameters of large-scale flexible structures. The actuator/sensor placement algorithm maximizes a modal controllability index improving the effectiveness of the control. Considering limitations of sensors and actuators, the controller is chosen as a stable, band-pass MIMO system resulting from the closed-form solution of a robust control problem. Experimental results on an aeronautical stiffened skin panel are presented using rapid-prototyping hardware.
This outstanding thesis by Dominic Bowman provides a thorough investigation of long-standing questions as to whether amplitude modulation is astrophysical, whether it offers insights into pulsating stars, and whether simple beating of modes with stable amplitudes is unrecognised because of a lack of frequency resolution. In this thesis, the author studied a uniform sample of 983 delta Scuti stars-the most common type of main-sequence heat engine pulsator-that were observed nearly continuously for 4 years at stunning photometric precision of only a few parts per million by the Kepler space mission. With no mission planned to supersede the Kepler 4-year data set, this thesis will stand as the definitive study of these questions for many years. With revolutionary photometric data from the planet-hunting Kepler space mission, asteroseismic studies have been carried out on many hundreds of main-sequence solar-type stars and about 10,000 red giants. It is easy to understand why those stochastically driven stars have highly variable amplitudes. Over much of the rest of the Hertzsprung-Russell (HR) diagram, stellar pulsations are driven by heat mechanisms, which are much more regular than the stochastic driving in solar-like pulsators. Yet for decades, amplitude and frequency modulation of pulsation modes have been observed in almost all types of heat-driven pulsating stars. The author shows that the amplitude and frequency modulation are astrophysical, and he has investigated their implications and prospects to provide new insights into the delta Scuti stars and the many other types of heat-engine pulsators across the HR diagram.
This book makes good background reading for much of modern magnetospheric physics. Its origin was a Festspiel for Professor Jim Dungey, former professor in the Physics Department at Imperial College on the occasion of his 90th birthday, 30 January 2013. Remarkably, although he retired 30 years ago, his pioneering and, often, maverick work in the 50's through to the 70's on solar terrestrial physics is probably more widely appreciated today than when he retired. Dungey was a theoretical plasma physicist. The book covers how his reconnection model of the magnetosphere evolved to become the standard model of solar-terrestrial coupling. Dungey's open magnetosphere model now underpins a holistic picture explaining not only the magnetic and plasma structure of the magnetosphere, but also its dynamics which can be monitored in real time. The book also shows how modern day simulation of solar terrestrial coupling can reproduce the real time evolution of the solar terrestrial system in ways undreamt of in 1961 when Dungey's epoch-making paper was published. Further contributions on current Earth magnetosphere research and space plasma physics included in this book show how Dungey's basic ideas have remained explanative 50 years on. But the Festspiel also introduced some advances that possibly Dungey had not foreseen. One of the contributions presented in this book is on the variety of magnetospheres of the solar system which have been seen directly during the space age, discussing the variations in spatial scale and reconnection time scale and comparing them in respect of Earth, Mercury, the giant planets as well as Ganymede.
This book describes how biologically available free energy sources (ATP, chemical potential, and membrane potentials, among others) can be used to drive synthetic reactions, signaling in cells, and various types of motion such as membrane traffic, active transport, and cell locomotion. As such, it approaches the concept of the energy cycle of life on Earth from a physical point of view, covering topics ranging from an introduction to chemical evolution, to an examination of the catalytic activity of enzymes associated with the genome in Darwinian evolution. The author introduces the relationship between functions and physical properties in biomembranes, explaining the methods and equipment used in biophysics research to help researchers unravel the still-unsolved mysteries of life. The physical principles needed to understand the cellular functions are provided; these functions are associated with biomembranes and regulated by physical properties of the lipid bilayer such as membrane fluidity, phase transition, and phase separation, as shown in lipid rafts. Other key dynamic aspects of life (cell locomotion, cytoskeletal dynamics, and sensitivities of the cell to physical stimuli such as external forces and temperature) are also discussed. Lastly, readers will learn how life on Earth and its ecological system are maintained by solar energy, and be provided further information on the problems accompanying global warming.
The model-based investigation of motions of anthropomorphic systems is an important interdisciplinary research topic involving specialists from many fields such as Robotics, Biomechanics, Physiology, Orthopedics, Psychology, Neurosciences, Sports, Computer Graphics and Applied Mathematics. This book presents a study of basic locomotion forms such as walking and running is of particular interest due to the high demand on dynamic coordination, actuator efficiency and balance control. Mathematical models and numerical simulation and optimization techniques are explained, in combination with experimental data, which can help to better understand the basic underlying mechanisms of these motions and to improve them. Example topics treated in this book are * Modeling techniques for anthropomorphic bipedal walking systems * Optimized walking motions for different objective functions * Identification of objective functions from measurements * Simulation and optimization approaches for humanoid robots * Biologically inspired control algorithms for bipedal walking * Generation and deformation of natural walking in computer graphics * Imitation of human motions on humanoids * Emotional body language during walking * Simulation of biologically inspired actuators for bipedal walking machines * Modeling and simulation techniques for the development of prostheses * Functional electrical stimulation of walking.
Mass spectrometry is fast becoming an indispensable field for
medical professionals. The mass spectrometric analysis of
metabolites and proteins promises to revolutionize medical research
and clinical diagnostics. As this technology rapidly enters the
medical field, practicing professionals and students need to
prepare to take full advantage of its capabilities.
The thesis represents the development of an entirely new experimental platform for generating and studying converging radiative shock waves. It was discovered that the application of large magnetic pressures to gas-filled cylindrical metallic tubes could sequentially produce three shocks within the gas. A comprehensive set of instrumentation was devised to explore this system in detail and an exceptionally thorough experimental and theoretical study was carried out in order to understand the source of the shock waves and their dynamics. The research is directed towards some of the most interesting topics in high energy density physics (HEDP) today, namely the interaction of HED material with radiation and magnetic fields, with broad applications to inertial confinement fusion (ICF) and laboratory plasma astrophysics. The work has already generated significant international interest in these two distinct research areas and the results could have significant importance for magnetic ICF concepts being explored at Sandia National Laboratories in the US and for our understanding of the very strong shock waves that are ubiquitous in astrophysics.
The Workshop "Science with the VLT in the ELT Era" held in Garching from 8th to 12th October 2007 was organised by ESO, with support from its Scienti c and Technical Committee, to provide a forum for the astronomical community to debate the long term future of ESO's Very Large Telescope (VLT) and its interferometric mode (VLTI). In particular it was considered useful for future planning to evaluate how its science use may evolve over the next decade due to competition and/or synergy with new facilities such as ALMA, JWST and, hopefully, at least one next generation 30-40 m extremely large telescope whose acronym appears in the title to symbolise this wider context. These discussions were also held in the fresh light of the Science Vision recently developed within ASTRONET as the rst step towards a 20 year plan for implementing astronomical facilities-the rst such attempt within Europe. Speci c ideas and proposals for new, second generation VLT/I instruments were also solicited following a tradition set by several earlier Workshops held since the start of the VLT development. The programme consisted of invited talks and reviews and contributed talks and posters. Almost all those given are included here although, unfortunately not the several lively but constructive discussion sessions.
This prize-winning Ph.D. thesis by Chris Harrison adopts a multi-faceted approach to address the lack of decisive observational evidence, utilising large observational data sets from several world-leading telescopes. Developing several novel observational techniques, Harrison demonstrated that energetic winds driven by Active Galactic Nuclei (AGN) are found in a large number of galaxies, with properties in agreement with model predictions. One of the key unsolved problems in astrophysics is understanding the influence of AGN, the sites of growing supermassive black holes, on the evolution of galaxies. Leading theoretical models predict that AGN drive energetic winds into galaxies, regulating the formation of stars. However, until now, we have lacked the decisive observational evidence to confirm or refute these key predictions. Careful selection of targets allowed Harrison, to reliably place these detailed observations into the context of the overall galaxy population. However, in disagreement with the model predictions, Harrison showed that AGN have little global effect on star formation in galaxies. Theoretical models are now left with the challenge of explaining these results.
Nanoneuroscience is the study of computationally relevant biomolecules found inside neurons. Because of recent technological advances at the nanometer scale, scientists have at their disposal increasingly better ways to study the brain and the biophysics of its molecules. This book describes how biomolecules contribute to the operations of synapses and perform other computationally relevant functions inside dendrites. These biomolecular operations considerably expand the brain-computer analogy - endowing each neuron with the processing power of a silicon-based multiprocessor. Amazingly, the brain contains hundreds of billions of neurons.
This book presents the concepts and tools of ice mechanics, together with examples of their application in the fields of glaciology, climate research and civil engineering in cold regions. It starts with an account of the most important physical properties of sea and polar ice treated as an anisotropic polycrystalline material, and reviews relevant field observations and experimental measurements. The book focuses on theoretical descriptions of the material behaviour of ice in different stress, deformation and deformation-rate regimes on spatial scales ranging from single ice crystals, those typical in civil engineering applications, up to scales of thousands of kilometres, characteristic of large, grounded polar ice caps in Antarctica and Greenland. In addition, it offers a range of numerical formulations based on either discrete (finite-element, finite-difference and smoothed particle hydrodynamics) methods or asymptotic expansion methods, which have been used by geophysicists, theoretical glaciologists and civil engineers to simulate the behaviour of ice in a number of problems of importance to glaciology and civil engineering, and discusses the results of these simulations. The book is intended for scientists, engineers and graduate students interested in mathematical and numerical modelling of a wide variety of geophysical and civil engineering problems involving natural ice.
If science has the equivalent of a Bloomsbury group, it is the five
men born at the turn of the twentieth century in Budapest: Theodore
von Karman, Leo Szilard, Eugene Wigner, John von Neumann, and
Edward Teller. From Hungary to Germany to the United States, they
remained friends and continued to work together and influence each
other throughout their lives. As a result, their work was integral
to some of the most important scientific and political developments
of the twentieth century. |
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