bluuebunny/crossref_metadata_2025_split huggingface dataset:
Space charge and instabilities
Authors: Wilson E. J. N. 
Published: January 2010

Abstract
This chapter treats collective effects of the beam upon individual particles. It first treats the transverse space charge forces and how they detune the beam. The effect is worst for non-relativistic particles. A tolerable limit is established. The concept of instabilities, in which beam fluctuations have a positive feedback causing growth, are introduced with the Negative Mass instability. Next, the A.C. component of the beam current is shown to excite fields in cavity-like objects. These react back on the beam. The growth rate of the instability is equivalent to an imaginary shift in synchrotron frequency equal to the square root of the beam current multiplied by an impedance—the energy increment seen by the beam—divided by the beam current itself. Contours of stability or growth rate are shown in a plot of the reactive versus resistive impedance. Landau damping produces an area of stability described by the Keil–Schnell Criterion.
Applications of accelerators
Authors: Wilson E. J. N. 
Published: January 2010

Abstract
Thousands of low and medium energy accelerators are used in industry, medicine, and for research. Applications include ion implantation for computer chips, hardening of plastics, surface treatment of metals, precision machining of miniature components and membranes, sterilisation of food, packaging, and in industrial waste disposal. Synchrotrons provide synchrotron light for studies of complex crystal structures, proteins, and other molecules. Protons are accelerated to produce neutrons by spallation for diffraction studies of similar structures. Principal medical applications include cyclotrons for isotope production as well as linacs, and proton and ion synchrotrons for advanced cancer therapy. Van der Graaf and other low emery accelerators are used for a variety of scattering experiments including carbon dating and material analysis. Future large-scale applications include energy production by heavy-ion fusion and accelerator-driven reactors.
Interatomic Forces in Condensed Matter
Authors: Finnis Mike 
Published: January 2010

AbstractThere is a continuing growth of interest in the computer simulation of materials at the atomic scale, using a variety of academic and commercial computer programs. In all such programs there is some physical model of the interatomic forces. For a student or researcher, the basis of such models is often shrouded in mystery. It is usually unclear how well founded they are, since it is hard to find a discussion of the physical assumptions that have been made in their construction. The lack of clear understanding of the scope and limitations of a given model may lead to its innocent misuse, resulting either in unfair criticism of the model or in the dissemination of nonsensical results. In this book, models of interatomic forces are derived from a common physical basis, namely the density functional theory. The book includes the detailed derivation of pairwise potentials in simple metals, tight-binding models from the simplest to the most sophisticated (self-consistent) kind, and ionic models. It provides a critical appreciation of the broad range of models in current use, and provides the tools for understanding other variants that are described in the literature. Some of the material is new, and some pointers are given to possible future avenues of model development.
Hybrid Schemes
Authors: Finnis Mike 
Published: January 2010

AbstractThis chapter discusses two types of interatomic potentials for metallic systems that take neither the approach of perturbing a free electron gas nor of superimposing atomic charge densities and doing tight binding. Rather they combine aspects of both. The first is generalized pseudopotential theory, which subsumes and generalizes the pair-potential approach, while systematically adding three-body and four-body contributions to the total energy. It has proved very useful for the simulation of transition metals. The second is effective medium theory, which after much simplification becomes identical to the embedded atom method. The relative merits of different approaches are discussed.
3 The basic theory of neutron scattering
Authors: Hempelmann Rolf 
Published: January 2010

Abstract
This chapter discusses ways to describe theoretically neutron scattering as a probe for condensed matter, first the scattering on a rigidly bound and isolated nucleus by the neutron-nucleus interaction as well as coherent and incoherent neutron scattering. Then the corresponding matrix element, in terms of perturbation theory of quantum mechanics, is derived which yields the double differential scattering cross-section of the sample as a function of momentum and energy transfer of the scattered neutrons. With the concept of the van Hove correlation functions, this matrix formulation is finally transformed into classical correlation functions, which are convenient if the particle motion can be described by classical dynamical models. In this way, the coherent scattering function S(Q, ω) is the double Fourier transform of the correlation function G(r,t), whereas the incoherent scattering function Si(Q, ω) is the double Fourier transform of the self-correlation function Gs(r,t). The convolution approximation relates S(Q, ω) to Si(Q, ω). The scattering intensity decreases with increasing Q due to the Debye–Waller factor which is directly connected to lattice vibrations.
11 Solid state proton conductors
Authors: Hempelmann Rolf 
Published: January 2010

Abstract
Aliovalently doped perovskite-type oxides (e.g., SrCeO3 doped with Yb2O3) contain, for reasons of charge neutrality, oxygen vacancies and become high temperature proton conductors in the presence of water. Proton conductivity is due to OH- ions on oxygen sites and to proton hopping from oxygen to oxygen according to the Grotthuss mechanism. This chapter examines aliovalently doped perovskites both by QENS and by muon spin rotation. It evaluates the QENS data in terms of the two-state model. Hydrogen bonded systems like CsHSO4 are another class of solid proton conductors. For these compounds, QENS also delivers an atomistic picture of proton diffusion. Another proton carrier is NH3 intercalated in molybdenum bronzes.
Long-wavelength emitters on GaAs
Authors: Ustinov Victor M. , Zhukov Alexey E. , Egorov Anton Yu. , Maleev Nikolai A. 
Published: January 2010

AbstractThis chapter is devoted to laser structures on GaAs substrates, which are capable of operating near the 1.3-um spectral window. Firstly, motivation for long-wavelength emitters on GaAs is discussed and possible semiconductor materials, suitable for 1.3-um application, are compared. The main part of the chapter is focused on long-wavelength quantum dot lasers. Various approaches for epitaxial deposition of long-wavelength QDs are described. The device characteristics of diode lasers comprising quantum dots formed either with atomic layer epitaxy or dots-in-a-well method are then compared. Efficiency, threshold, and temperature characteristics of long-wavelength QD lasers are also discussed. For the sake of comparison, data on non-QD laser structures are presented. InGaAsN quantum wells and diode lasers based on them are also discussed in detail.
14 Propagation of X-rays in highly deformed crystals
Authors: AUTHIER ANDRÉ 
Published: January 2010

Abstract
This chapter concerns highly deformed crystals where the Eikonal approximation is no longer valid. An expression is given for the limit of validity of this approximation. Takagi's equations are extended so as to apply to highly deformed crystals. Their resolution is the discussed and the principle of their numerical integration in an inverted Borrmann triangle given. The ray concept is generalized to the case of strong deformations by noting that new wavefields are generated in the highly strained regions; this is known as the interbranch scattering effect. The last part of the chapter is devoted to an account of the statistical dynamical theories for highly imperfect crystals, with emphasis on Kato's statistical theories. Examples of experimental test of the dynamical theory are also given.
17 X-ray diffraction topography
Authors: AUTHIER ANDRÉ 
Published: January 2010

Abstract
This chapter describes the various techniques for obtaining X-ray topographs: single-crystal reflection topography (Berg-Barrett), single crystal transmission topography (Lang, section and projection topographs, synchrotron white beam topographs), and double or multiple-crystal topography (plane-wave, synchrotron topography, high-resolution). The formation of the images of the different types of individual defects and their contrast are discussed for the different experimental settings: dislocations, stacking faults, planar defects, and twins. It is shown how long range strains and lattice parameter variations can be mapped. Equal-strain and equal lattice parameter contours are described. Many examples of the use of topography for the characterization of materials are given.
Accurate Clock Pendulums
Authors: Matthys Robert J. 
Published: January 2010

Abstract
The Shortt clock, made in the 1920s, is the most famous accurate clock pendulum ever known, having an accuracy of one second per year when kept at nearly constant temperature. Almost all of a pendulum clock's accuracy resides in its pendulum. If the pendulum is accurate, the clock will be accurate. This book describes many scientific aspects of pendulum design and operation in simple terms with experimental data, and little mathematics. It has been written, looking at all the different parts and aspects of the pendulum in great detail, chapter by chapter, reflecting the degree of attention necessary for making a pendulum run accurately. The topics covered include the dimensional stability of different pendulum materials, good and poor suspension spring designs, the design of mechanical joints and clamps, effect of quartz on accuracy, temperature compensation, air drag of different bob shapes and making a sinusoidal electromagnetic drive. One whole chapter is devoted to simple ways of improving the accuracy of ordinary low-cost pendulum clocks, which have a different construction compared to the more expensive designs of substantially well-made ones. This book will prove invaluable to anyone who wants to know how to make a more accurate pendulum or pendulum clock.
A short history of temperature compensation
Authors: Matthys Robert James 
Published: January 2010

Abstract
This chapter covers the temperature compensation of pendulum clocks. Temperature compensators can be divided into four groups: mercury for medium expansion pendulum rods (iron), gridiron for medium expansion pendulum rods (iron), sleeve for low expansion pendulum rods (invar, quartz), and miscellaneous low accuracy schemes (bimetal, length of the suspension spring, barometer on pendulum, and gears and levers). The story starts in the early 1700s, when people noticed that different metals expanded at different rates. Several clockrnakers independently measured the relative thermal expansions of different metals, with each using his own arbitrary scale of expansion.
Some practical properties of quartz
Authors: Matthys Robert James 
Published: January 2010

Abstract
The big attraction of quartz as a pendulum material is its good dimensional stability over time. Stability over time is the biggest and most needed characteristic in an accurate pendulum. In contrast to invar, which was known to be unstable almost from its beginning, quartz has a long history of being a stable material. Dimensional stability is not the same as low thermal expansion. If a pendulum is temperature compensated, as all accurate pendulums are, then it does not matter much what the thermal expansion coefficient is, so long as the compensation has been done accurately. The accuracy of temperature compensation is limited by factors other than the thermal expansion coefficient. Because of their low density, quartz pendulum rods do have one drawback: they have a much higher sensitivity to barometric pressure changes than invar.
Dimensional stability of pendulum materials
Authors: Matthys Robert James 
Published: January 2010

Abstract
The dimensional stability of a pendulum directly affects its accuracy. If the bob sags downward or warps upward, the clock slows down or speeds up. If the temperature compensator shrinks or expands in length, the same thing happens. If the pendulum rod gets longer or shorter, again the clock slows down or speeds up. It does not take much to disturb an accurate dock. Unless a pendulum is kept in a constant temperature room, it is apparent that heat treatment will improve the pendulum's stability by 2-8 times, the exact amount of improvement depending on the material. The combination of annealing plus temperature cycling is very effective in reducing the thermal hysteresis of pendulum materials, making a pendulum clock more stable and more accurate in the typical home environment where the temperature is not perfectly constant.
Stable connections to a pendulum’s suspension spring
Authors: Matthys Robert James 
Published: January 2010

Abstract
Chops, located on the ends of a pendulum's suspension spring, are designed to get a more solid grip on the spring. With a degree of helpfulness varying from outstanding to useless, chops give a constant fixed length to the suspension spring and prevent the suspension spring from rocking back and forth on the top edge of the crosspin through the top end of the suspension spring. This chapter discusses the rocking of the suspension spring on one of its crosspins. A typical suspension spring has its ends pinned in narrow slots and contains no chops, with the slots slightly wider than the thickness of the spring. As the pendulum swings back and forth, the spring's ends bend or wiggle back and forth a little in the slots. The wiggling is more pronounced in the top slot than in the bottom slot. There would be no rocking motion if the spring's ends were a tight fit in the slots.
The instability of invar
Authors: Matthys Robert James 
Published: January 2010

Abstract
Almost since its invention in 1896, invar has been known to be a dimensionally unstable pendulum rod material. A few articles have been published over the years, trying to address the dimensional instability and eliminate it. Data published in 1927 showed a dimensional growth of 50 ppm over a 27-year interval. The growth was exponential, gradually slowing down with time. Invar's growth today still follows the same exponential pattern, although shrinkage is occasionally observed. In 1950, invar's instability was tied to the presence of impurities, especially carbon. The lower the level of impurities, the more stable the invar is. Invar's impurity level has been reduced over the years, so that today's invar, using the traditional furnace melt process, is more stable than it was 20 years ago. Today's regular invar has a dimensional stability of 2-27 ppm per year, at room temperature. There are three types of invar available today: regular invar, free machining invar, and super invar. Super invar's thermal expansion coefficient is three times smaller than that of regular invar.
Position sensitivity along the pendulum rod
Authors: Matthys Robert James 
Published: January 2010

Abstract
Every clock's pendulum needs a fine trim to adjust its rate to the desired value. This is frequently done by adding small weights to a weight pan, which is usually located about one-third of the way down the pendulum rod. The clock literature says that the effect of adding a small weight to a pendulum will vary, depending on the weight's location along the pendulum rod. The literature also says that the weight will have maximum effect on the pendulum's rate if placed halfway between the bob and the suspension spring, and will have zero effect if placed at the center of the bob or at the suspension spring. This chapter describes an experiment that was carried out to measure the position sensitivity of a pendulum rod by clamping a 24-gram weight on the pendulum rod at a given location and calculating the change in clock rate.
Effect of the pendulum rod on Q
Authors: Matthys Robert James 
Published: January 2010

Abstract
A pendulum rod's air drag has a significant effect on the pendulum's Q. Many years ago, an experiment was carried out to determine the effect of bob shape on a pendulum's Q. The results showed that a football-shaped bob, pointed horizontally in the direction of swing, had the highest Q (least air drag) of any bob shape tested. The highest Q shape had a 2:1 length-to-diameter ratio. Spherical bobs had a little lower Q and right circular cylinders, with their cylindrical axis parallel to the pendulum rod's axis, had even lower Q. This chapter describes an experiment to measure the effect of the pendulum rod on Q. The pertinent rod variable is the rod's diameter. The data show that the Q decreases as the rod's diameter increases, and that the pendulum's Q with a spherical bob is 6-20% better than with a cylindrical bob. Better Q means proportionately better timekeeping.
Pendulum air movement: A failed experiment
Authors: Matthys Robert James 
Published: January 2010

Abstract
A previous experiment showed that the walls of a pendulum clock case can slow down the pendulum via air drag by about 1 second per day. The pendulum has a 2-second period. This chapter describes an experiment designed to find out if the walls' drag on the pendulum could be reduced or made more constant by shaping the walls' inside surface for easier air flow. The concept basically involved rounding the square corners inside the clock case. The results show that a spherical bob had the smoothest airflow, while a large cylindrical bob disturbed the most air. There was very little, if any, air movement near the clock case walls. Any further attempt to affect the airflow should be aimed at the bob's surface-to-air interface, and not at the case walls.
Pendulum air movement: A second try
Authors: Matthys Robert James 
Published: January 2010

Abstract
Air drag is the biggest energy loss in a pendulum. The bob generates most of the air drag because of its large size and its location at the end of the pendulum rod. In this chapter, the movement of air around four different pendulum bobs is shown by white smoke in a series of pendulum photographs. The photos provide general information on airflow around the pendulum bob, but not much specific information that can be used to reduce the air drag and the pendulum's energy losses. Changing from a cylindrical to a spherical bob shape will reduce the energy losses and improve the pendulum's Q by 6-20%. But it takes about twice as much material (doubling the cost) and about four times as much effort to make a spherical bob as it does to make a cylindrical one. The best solution is to operate the clock in a vacuum chamber, although vacuum chambers have problems of their own.
Sonine Polynomials Expansion of The Velocity Distribution Function
Authors: Brilliantov Nikolai V. , Pöschel Thorsten 
Published: January 2010

Abstract
The velocity distribution of function of a granular gas is different from the Maxwell distribution. It may be represented in the form of a Sonine polynomials expansion. This chapter shows that the coefficients of this expansion describe the moments of the velocity distribution function. The first non-trivial Sonine coefficient a2 is of particular interest for the gas kinetics.
Velocity Distribution Function and Temperature for Viscoelastic Particles
Authors: Brilliantov Nikolai V. , Pöschel Thorsten 
Published: January 2010

Abstract
This chapter shows that for granular gases of viscoelastic particles, the shape of the velocity distribution function cannot be described by a time-dependent function. Instead, it evolves along with decaying temperature. Its complicated time dependence allows the definition of the age of a granular gas.
Nonlinear Mechanisms of Structure Formation
Authors: Brilliantov Nikolai V. , Pöschel Thorsten 
Published: January 2010

Abstract
The enslaving temperature by the shear mode leads to an inverse dependence of pressure on density, that is, to a clustering instability. This chapter shows that for a granular gas of viscoelastic particles, the conditions of temperature enslaving by the shear mode are not satisfied after a period of gas evolution.
Methods in Theoretical Quantum Optics
Authors: Barnett Stephen M. , Radmore Paul M. 
Published: January 2010

AbstractThis book provides a firm grounding in those techniques needed to derive analytic solutions to relevant model problems. The book begins with a brief review of the mathematical foundations of quantum theory, especially those relevant to the description of atoms and optical fields and their coherent interactions. The following chapters treat the operators and states required, the rules for manipulating these, and the techniques commonly employed for calculating their statistical properties. A chapter is devoted to the important topic of dissipative processes and to the effects that these have on quantum optical systems. The final chapter discusses dressed states, that is, the eigenstates of interacting systems, including those that are dissipative. Fourteen short appendices summarize the more important topics in mathematics required in the book or present the lengthier calculations not included in the chapters. A selective bibliography is given at the end of the book.
Dissipative Processes
Authors: BARNETT STEPHEN M. , RADMORE PAUL M. 
Published: January 2010

AbstractThis chapter treats dissipation arising from coupling to the environment. Problems treated include photoionization, spontaneous emission, and cavity damping. A short-time perturbative analysis leads to decay of a single state coupled to a continuum at a rate determined by Fermi's golden rule. For longer times a non-perturbative solution of the amplitude equations leads to Weisskopf–Wigner decay. The final value theorem provides a simple method for obtaining the final state spectrum without first solving for the dynamics. A Heisenberg picture analysis leads to operator Langevin equations in which environment operators introduce quantum noise. A parallel analysis is possible working in the Schroedinger picture and leads to a master equation for the density operator of the damped system. This is solved to provide a complete description of the influence of dissipation on the system of interest. It is sometimes simpler to solve directly for the evolution of the field statistics.
Introduction to Lagrangian Mechanics
Authors: Johns Oliver 
Published: January 2010

Abstract
If modern mechanics began with Isaac Newton, modern analytical mechanics can be said to have begun with the work of the 18th-century mathematicians who elaborated his ideas. Without changing Newton’s fundamental principles, Leonhard Euler, Pierre-Simon Laplace, and Joseph Louis Lagrange developed elegant computational methods for the increasingly complex problems to which Newtonian mechanics was being applied. The Lagrangian formulation of mechanics is, at first glance, merely an abstract way of writing Newton’s second law: the law of angular momentum. This chapter discusses Lagrangian mechanics as well as configuration space, Newton’s second law in Lagrangian form, arbitrary generalised coordinates, generalised velocities in the q-system, generalised forces in the q-system, expression of Lagrangian mechanics in the q-system, invariance of the Lagrange equations, generalised momenta in the q-system, ignorable coordinates, generalised energy function, generalized energy and total energy, and velocity dependent potentials.