bluuebunny/crossref_metadata_2025_split huggingface dataset:
X-ray crystallography: an introduction
Authors: Glusker Jenny P , Domenicano Aldo 
Published: November 2023

Abstract
The chemist would like to be able to visualize molecules and the atoms in them and so obtain a direct three-dimensional view. For example, when considering reaction mechanisms it is difficult to determine the extent of steric hindrance or the accessibility of functional groups if one does not have a three-dimensional view of the system. The electron microscope can, as was shown, for example, by Labaw and Wyckoff (1958), be used to view macromolecules such as those of viruses. It can also be used to image the lattice defects in certain stable inorganic compounds (Iijima 1973). But when one needs precise geometrical data on molecules, an excellent method to choose is an analysis of the X-ray or neutron diffraction patterns obtained from single crystals of the substance of interest. The result of such an analysis is a vast wealth of data on the relative positions of atoms, ions or molecules in a crystal, and a measure of the variability of these positions.
Diffraction studies of molecular motion in crystals
Authors: Trueblood Kenneth N 
Published: November 2023

Abstract
Debye (1913) recognized almost immediately after the discovery of X-ray diffraction that diffraction experiments could make possible determination of the mean-square vibration amplitudes of atoms in crystals. Until the advent of high-speed computing in the 1950s, however, it was not possible to determine atomic vibration amplitudes sufficiently well to permit analysis of the motion of molecules in crystals. Then, in a remarkable series of papers, Cruickshank showed how to determine parameters to describe the anisotropic motion of atoms (Cruickshank 1956a), how to use these parameters to describe rigid-body motion of molecules (Cruickshank 1956b), and how to correlate this motion with the thermodynamic and spectroscopic properties of molecular crystals (Cruickshank 1956d, e, f). Furthermore he showed (Cruickshank 1956c, 1961) that librational molecular motion (i.e. rotational oscillation) could lead to apparent foreshortening of intramolecular distances, an important conclusion reached independently by Busing and Levy (1957, 1964).
Crystallographic databases: retrieval and analysis of precise structural information from the Cambridge Structural Database
Authors: Allen Frank H 
Published: November 2023

Abstract
X-ray crystallography is the most widely used technique for the study of molecular structure at atomic resolution. Developments in theory, instrumentation and computer technology, described in earlier chapters of this volume, have led to a dramatic increase in the number of diffraction analyses over the past twenty years. A single-crystal study now takes days rather than months with the result that X-ray analysis is now a method of choice rather than a method of last resort. This is borne out by the data embodied in Table 15.1 and Fig. 15.1: over 100 000 full three-dimensional analyses have been reported in the literature, over 50 per cent of these have been published since 1980. The improved precision of routine data collection methods has also led to significant improvements in the precision of the resultant structures.
The importance of accurate structure determination in organic chemistry
Authors: Wipff Georges , Boudon Stéphane 
Published: November 2023

Abstract
Structural information is essential in chemistry not only for determining the geometrical arrangement of atoms within a molecule or a crystal, but also because every structure may tell us something about the electron distribution, the type and properties of bonds connecting the atoms in their potential energy minima, and, to some extent, about their reactivity (Dunitz 1979). Chemists have not waited for structure determinations to develop a structural theory of the chemical bond and to write down chemical formulae which account for the reactivity and the presumed structure of molecules. It has been a great success of chemical reasoning to think in terms of structure before it had been established by physical methods. In many cases, these formulae and speculated structures derived by deductive reasoning from chemical phenomena correspond closely to the observed atomic arrangements; a detailed example is given in Chapter 1.
Structure correlations, reaction pathways, and energy surfaces for chemical reactions
Authors: Ferretti Valeria , Dubler-Steudle Katharina C , Bürgi Hans-Beat 
Published: November 2023

Abstract
The use of spectroscopy and diffraction experiments, of ab initio MO and molecular mechanics calculations to study molecular structure has been described in detail in Chapters 3-14. These techniques are based on the elementary physical laws describing the interactions of nuclei, electrons, neutrons and electromagnetic radiation and, at least in principle, on a theoretical definition of the concept of molecular structure, namely the Born-Oppenheimer energy surface (Chapter 2). Over the years a host of information on equilibrium structures and molecular vibrations, mainly in the solid and gaseous states, has accumulated and part of it is compiled in several data banks (Chapter 15). The information is of a physical nature in so far as it is being obtained by physical methods and to the extent that it pertains to individual compounds.
Effect of crystal environment on molecular structure
Authors: Bernstein Joel 
Published: November 2023

Abstract
In a book on accurate molecular structures, it seems appropriate to address the problem of the effect of crystal forces on molecular geometry. Perhaps we should inquire at the outset as to whether there is a problem at all. Many of the previous chapters in this book have introduced a variety of techniques for the theoretical study and experimental determination of molecular structure in various media. Certainly the most widely used experimental technique today is X-ray crystallography and the information obtained from crystal structure analyses is often used directly to interpret and understand molecular phenomena which take place in media and molecular environment differing significantly from that of the molecule in the crystal. As a result, the molecular geometric parameters found in the crystal may, and often do, differ from those determined experimentally by other methods; likewise they may differ from the results of theoretical treatments in which we have sufficient basis for confidence in our models and methods to provide us with reliable information on the geometry of molecules.
Structural variability in metal cluster compounds
Authors: Albano Vincenzo G , Braga Dario 
Published: November 2023

Abstract
This chapter deals with the rationalization of some structural characteristics of the transition-metal cluster compounds containing carbon monoxide as principal ligand. The discussion has been confined to a few (in our opinion) relevant topics with the aim of developing them in some depth. This choice is made necessary by the enormous structural variability shown by the organometallic solid-state chemistry with respect to the type of molecules found in the organic area. Attention will also be focused on some aspects of the interplay between the molecular geometry determined by X-ray diffraction and the structural information obtainable by spectroscopic techniques.Metal cluster species are among the largest organometallic molecules currently studied, an average structural study usually implying treatment of several tens, if not hundreds, of atoms, a relevant proportion of which are transition metals (Chini et al. 1976). The size and nature of these molecules represent by themselves an a priori drawback for research work aimed at a high level of accuracy. It is hardly necessary to point out that some of the usual problems (absorption, anomalous dispersion, crystal decay, etc.) crystallographers are used to facing in the course of their work, are often considerably aggravated when large numbers of heavy atoms are present (Angermund et al. 1985). Last but not least, the light atoms make a limited contribution to the total scattering power of these molecules.
Cancer: radiotherapy
Authors: Bensasson R v. , Land E J , Truscott T G 
Published: November 2023

Abstract
Both normal and malignant cells are sensitive to high energy radiation. Although a long-term effect of high energy irradiation can be cancer induction, such radiation can also be used to treat cancer. Cancer is characterized by a pro gressive accumulation of malignant cells and the object of radiotherapy is to sterilize cancer cells so that they lose their capacity for unlimited proliferation. One of the important aims of radiation chemical and radiation biological studies is to provide information which may lead to the optimization of radiotherapy.
Oxygen, hydrogen peroxide, and water
Authors: Symons M C R , Gutteridge J M C 
Published: November 2023

Abstract
In Chapter 3 we spend some time with the system O2, O. 2 -HO. 2, HO- 2, H2O2, .OH, and H2O. This is because these simple chemical entities are at the heart of a wide range of important biological processes (see Fig. 3.1 for the four-electron reduction of 02), which often centre around iron.
The Fenton reaction
Authors: Symons M C R , Gutteridge J M C 
Published: November 2023

Abstract
In Chapter 5 we at last look the famous ‘Fenton reaction’ squarely in the face, by outlining the two major alternative mechanisms that are currently proposed. In section 5.5 we do our best to support the "OH radical as the major intermediate, whilst in Section 5.6 the case for Fe(IV) is outlined. Attention is then given to other metals, especially copper, and to other peroxides besides H202. In Section 5.9 possible reactions of the primary organic radicals are discussed. The difficult problem of Fenton processes occuring in membranes is then faced in Section 5.10. We end with a discussion of the Haber-Weiss process and some of the alternatives, and in a final tailpiece (‘coda’) we consider ways in which Nature protects against these reactions. (This aspect is fully described in Part II, Chapter 7.)
In-parallel Actuation I: Simple and Direct
Authors: Davidson Joseph K , Hunt Kenneth H 
Published: November 2023

Abstract
In-parallel actuated devices, often erroneously said to be recent developments, have a pedigree far more ancient than that of the serial robot-arms examined in earlier chapters. One precursor is the common adjustable tripod used by surveyors and, more recently, by photographers; it comprises a small triangular platform with straight supporting-legs of variable length which are hinged to it along its three sides. With the pointed feet well splayed out and firmly located on the ground, the platform can be raised, levelled, or tilted as desired by sliding the joints on the legs and then locking them. The tripod is light, yet sturdy; it is an ideal mount for a precision instrument. Nobody would ever have given a moment’s thought to designing an adjustable stand for a theodolite, say, along the lines of a serial robot-arm.
Circuit Description of Single Waveguide Structures
Authors: FachÉ Niels , Olyslager Frank , De Zutter Daniël 
Published: November 2023

Abstract
The goal of this chapter is to derive the circuit model of an arbitrary single waveguide structure starting from the Maxwell equations which govern the electromagnetic behaviour of the structure. The circuit model is associated with the fundamental mode of the waveguide structure. The model must be extended in the case when the waveguide structure behaves as a multimode waveguide. However, this extension is not addressed in this book.
Circuit Description of Two Coupled Lossless Waveguide Structures
Authors: FachÉ Niels , Olyslager Frank , De Zutter Daniël 
Published: November 2023

Abstract
In Chapter 2 the circuit model for a general waveguide structure supporting a single fundamental mode was derived. The circuit model is based upon the power equivalence and circuit principles. In the present chapter these two principles will be applied to construct the circuit model of two coupled lossless waveguide structures. The extension of the approach for single waveguide structures to two coupled waveguide structures was first presented in [1] The general case of an arbitrary number of coupled lossy or lossless waveguide structures will be discussed in Chapter 4.
General Introduction to the Full-Wave Analysis of Multiconductor Lines in a Planar Stratified Medium
Authors: FachÉ Niels , Olyslager Frank , De Zutter Daniël 
Published: November 2023

Abstract
In the first part of this book we examined in detail how a circuit model can be derived for a set of multiconductor transmission lines. The discussion was restricted to the propagating fundamental modes. The equivalent circuit model turned out to be a set of coupled transmission lines. The relation between the typical circuit quantities, that is, voltages, currents, (coupling) impedances, and signal velocities, and the original field quantities, that is, the modal fields 2.nd associated modal propagation constants, was determined.
For microstrip and stripline types of multiconductor structures the circuit models are based on the modal propagation constants, on the power propagated by the actual structure, and on the total longitudinal current flowing along each conductor. The modal propagation constants also become the propagation constants of the modes in the circuit model. The power equivalence principle ensures that the complex power propagated by the waveguide structure is the same as the one propagated by the circuit model. Finally, we identified the total longitudinal current flowing along each conductor with the circuit current. In this way we arrived at the power-current definition of the impedances.
Infinitely Thin Strip Transmission Line Structures
Authors: FachÉ Niels , Olyslager Frank , De Zutter Daniël 
Published: November 2023

Abstract
Single and coupled strip transmission line structures of which the microstrip is the best-known example are widely used in circuit design. A large body of literature has been devoted to the quasi-static and full-wave analysis of the circuit parameters of these structures. For an overview of the different quasi-static techniques used for microstrip design and the presentation of the most advanced techniques we refer the reader to [1] and [2].
Conditions Influencing The Performance Of Boiling And Condensing Systems
Authors: Collie John G , Eng F R S F , John R , Phil Thome D 
Published: November 2023

Abstract
In this chapter consideration will be given to methods of improving the performance of boiling and condensing heat transfer surfaces. Two aspects will be considered; firstly, methods of improving the heat transfer coefficient in boiling and condensing systems, and secondly, methods of increasing the critical heat flux for a boiling system. The latter part of the chapter is taken up with the problem of including the non-linear behaviour of the boiling side heat transfer characteristic in design methods and also a short comment on the related problems of corrosion and deposition in boiling systems, and their interaction with the hydraulic and thermal characteristics.
Contact-impact Problems with Material non-linearities
Authors: Zhong Zhi-Hua 
Published: November 2023

Abstract
In the preceding chapter, it was assumed that contact bodies consist of linearly elastic materials. The linearly elastic material model is valid for most materials only under a certain loading level. When the stress or the strain within the material reaches a certain level, the deformation of the material will no longer be linearly elastic, and non-linearly elastic and/or plastic deformation will occur. With plastic deformation, the stress–strain relation is no longer unique and will depend on the deformation history. In fact, even when the global deformation of a structure can be regarded as elastic, local plastic deformation can often be found in the structure. This is especially true when contacts are present, since contacts can often produce high local pressures on contacting boundaries as can be seen from some examples in the preceding chapter. More importantly, many contact-impact problems of great interest involve plastic deformation. In metal-forming processes, for example, plastic deformation of the workpiece is involved without exception. Another important case in which plastic deformation is involved is structural crashworthiness analysis in which structures are often subjected to heavy loadings. Owing to their practical importance, contact-impact problems involving plastic deformation are now considered in this chapter.
Contact-impact Problems with Large Displacements and Large Rotations
Authors: Zhong Zhi-Hua 
Published: November 2023

Abstract
In Chapters 4 to 6 it was assumed that contact bodies undergo only small displacements and thus small rotations and small deformation. Consequently, we restricted ourselves to only a special class of contact-impact problems. In engineering applications, however, there are many extremely important contact-impact problems that cannot be included in that special class. In metal-forming processes, for example, workpieces may undergo quite large displacements, large rotations, and large deformation. Thus the behaviour of the workpiece presents both geometric non-linearity and material non-linearity. Many assumptions made in Chapters 4 to 6 no longer apply. Instead, we have to use the more general formulation in Chapter 3.
Miscellaneous Topics
Authors: Zhong Zhi-Hua 
Published: November 2023

Abstract
We have discussed several important aspects of contact-impact problems, to each of which a whole chapter was devoted. There are, however, other topics which can be important in some engineering applications but have not been discussed or have not been discussed sufficiently in the previous chapters. As examples of those topics, we mention dynamic relaxation techniques, explicit — implicit procedures, adaptive meshes and re-zoning techniques, and vectorization and multitasking. These aspects can be crucial for some engineering applications, especially when the problem scale is large and complicated, and the deformation of the contact system is severe, as in the crashworthiness analysis of engineering structures and in the numerical simulation of metal-forming processes. Thus, this chapter is devoted to discussion of those topics which have received intensive study by many researchers as indicated by numerous publications. A comprehensive study of the topics cannot be contained in a single chapter and our discussion here will be brief and will only concern basic ideas and main procedures. Sample references to research work on these topics will be given when appropriate.
Bitransmission Lines For Full-Wave Fields
Authors: Olyslager Frank 
Published: November 2023

Abstract
This chapter is the natural extension of the previous three chapters. It is devoted to the representation of a general bianisotropic waveguide at arbitrary frequencies by transmission lines. In the previous chapter it was seen that the quasi-TEM analysis of electric bianisotropic waveguides yielded bitransmission lines. Hence, it is no surprise, that for the representation of the mode propagation in a bianisotropic waveguide at arbitrary frequencies, bitransmission lines are also needed.
Some classes of Sobolev spaces
Authors: Donato Patrizia 
Published: November 2023

Abstract
In this chapter we introduce the functional setting, essentially based on the distribution theory and Sobolev spaces, which is the natural framework for the homogenization results we present in this book. Distributions and Sobolev spaces have been widely studied in the last fifty years. We refer the reader for instance to Schwartz (1951), Nečas (1967), Lions and Magenes (1968a,b), Adams (1975), and Mazya (1985). We will quote here just the main results which will be used later. We also present, in the same context, some specific spaces of periodic functions as well as their main properties.
Bessel Functions of Other Kinds
Authors: Andrews Larry C 
Published: November 2023

Abstract
The Bessel functions of the first and second kinds studied in Chap. 6 are often referred to as the standard Bessel or cylinder functions. In addition to these, there are a host of related functions also belonging to the general family of cylinder functions, the most notable of which are the modified Bessel functions of the first and second kinds. Although similar in definition to the standard Bessel functions, the modified Bessel functions are most clearly distinguished by their nonoscillatory behavior. For this reason, they often appear in ap plications that are different in nature from those for the standard functions.
Applications Involving Bessel Functions
Authors: Andrews Larry C 
Published: November 2023

Abstract
Bessel functions are prominent in a variety of applications, some of which were discussed in Chaps. 6 and 7. Now we wish to consider some additional examples typical of those occurring in more than one field of application. To provide some variety in our discussions, we have chosen examples from the fields of mechanics, wave propagation and scattering, fiber optics, heat conduction in solids, and vibration phenomena.
The Confluent Hypergeometric Functions
Authors: Andrews Larry C 
Published: November 2023

Abstract
Whereas Gauss was largely responsible for the systematic study of the hypergeometric function, E. E. Kummer (1810-1893) is the person most associated with developing properties of the related confluent hypergeometric function. Kummer published his work on this function in 1836,* and since that time it has been commonly referred to as Kummer’s function. Like the hypergeometric function, the confluent hypergeometric function is related to a large number of other functions.
Forced oscillations: harmonic and subharmonic response, stability, entrainment
Authors: Jordan D W , Smith P 
Published: November 2023

Abstract
There are two parts combined additively. One part, the ‘free oscillation’ is a linear combination of the solutions of the homogeneous equation and involves the initial conditions. The second part, the ‘forced solution’, is proportional to F and is independent of initial conditions. When damping is present the free oscillation dies away in time. This independence of the free and the forced components, and the ultimate independence of initial conditions when there is damping allows a very restricted range of phenomena: typically the only things to look at are the amplitude and phase of the ultimate response, the rate of decay of the free oscillation, and the possibility of resonance. When the equation is nonlinear, on the other hand, there is no such simple separation possible, and the resulting interaction between the free and forced terms, especially when a self-excited motion is possible, and the enduring importance of the initial conditions in some cases, generates a range of entirely new phenomena. The present Chapter is concerned with using the method of harmonic balance (Chapter 4) and the perturbation method (Chapter 5) to obtain approximate solutions which clearly show these new features.
Stability
Authors: Jordan D W , Smith P 
Published: November 2023

Abstract
The word ‘stability’ has been used freely as a descriptive term in earlier Chapters. In Chapter 2 equilibrium points are classified as stable or unstable according to their appearance in the phase diagram. Roughly speaking, if every initial state close enough to equilibrium leads to states which continue permanently to be close, then the equilibrium is stable. Some equilibrium states may be thought of as being more stable than others: for example, all initial states near a stable node lead ultimately into the node, but in the case of a center there always remains a residual oscillation after disturbance of the equilibrium. Limit cycles are classified as stable or unstable according to whether or not ‘nearby’ paths ‘spiral’ into the limit cycle. In Chapter 7 we considered the stability of forced periodic oscillations, reducing the question to that of the stability of the corresponding equilibrium points on a van der Pol plane.