National Institute of Standards and Technology

Proudly serving the scientific community for over a century, this 95th edition of the CRC Handbook of Chemistry and Physics is an update of a classic reference, mirroring the growth and direction of science. This venerable work continues to be the most accessed and respected scientific reference in the world. An authoritative resource consisting of

Proudly serving the scientific community for over a century, this 97th edition of the CRC Handbook of Chemistry and Physics is an update of a classic reference, mirroring the growth and direction of science. This venerable work continues to be the most accessed and respected scientific reference in the world. An authoritative resource consisting of tables of data and current international recommendations on nomenclature, symbols, and units, its usefulness spans not only the physical sciences but also related areas of biology, geology, and environmental science. The 97th edition of the Handbook includes 20 new or updated tables along with other updates and expansions. It is now also available as an eBook. This reference puts physical property data and mathematical formulas used in labs and classrooms every day within easy reach.

This second edition of this very successful book is a welcome update which should benefit both the rapidly growing user community and researchers who want to keep track of active recent developments and some hot topics in the growing area of statistical learning and data mining. When the book first appeared in 2002, it was a shock to see many techniques inspired from the computer science literature being embraced side by side with modern multivariate regression techniques, many of which were developed either by the third author, either individually or in collaboration with others, or the first two authors together. It was probably due to the late Leo Breiman who brought V. Vapnik’s work on the support vector machine to the attention of the statistical community, which is covered in Chapter 12 (‘Support vector machines and flexible discriminants’) (see Vapnik (1999)), which led to the revival of a key statistical area with a new catchy name, and inspired much recent interest in sparse modelling, though his work is very close to the familiar smoothing spline formulation by Wahba and others (see Wahba (1990)). The influence of computer and information sciences is apparent throughout the book. For example, the 1993 National Institute of Standards and Technology database as a benchmark inspired development of many methods discussed in Chapter 11 and Chapter 13. Vapnik (1999), page 173, discussed the superior performance of the support vector machine on these benchmark data, building on earlier work using variants of neural network methods. Many algorithms that are covered in the book are taken directly from the computer science literature such as those in Chapter 10 (‘Boosting and additive trees’) and many in Chapter 14 (‘Unsupervised learning’). Of the four new chapters, Chapter 15 (‘Random forests’) is based directly on Leo Breiman’s application of the ideas of bagging and boosting (which are discussed earlier in Chapter 8 and Chapter 10) to improve the tree methodology (which is discussed in Chapter 9). Chapter 16 (‘Ensemble learning’) covers more recent developments of applying boosting ideas to many other machine learning methods. Although choosing new topics to add to an already successful book is a difficult task, however, I feel that the choice of topics in Chapter 17 could have been done better, as it does not fit well with the rest of the book and does a poor service to the large area of graphical modelling. Instead, some mention of causality concepts such as Pearl (2009) may be more pertinent to the prediction flavour of the book. The last new chapter (Chapter 18, ‘High-dimensional problems: P≫N’) provides a welcome survey of some recent statistical thinking on selected topics on the theory of analysing high dimensional data. However, because this is an area of much current statistical research interest I think it left much more to be desired, which I shall explain later. Various other changes have been made throughout the book. However, the authors have chosen to leave most of the earlier chapters intact to preserve the familiarity for current readers. Indeed, Chapters 1–8 present a nice set of materials for a basic statistical introduction to regression modelling and model inference. The authors have clearly demonstrated their expertise and great insights in various places such as sections 3.4 (‘Shrinkage methods and Lasso’), 3.5 (‘Partial least squares’) and 3.8 (‘New developments on Lasso’) and Chapter 7 (‘Model assessment and selection’). Chapter 7 and Chapter 8 (‘Model inference and averaging’) comprise an important part of the book on the statistical principles for data mining, though model validation is rarely based on within-data assessment alone. Although I think that the strength of the book is to provide several statistical themes as guiding principles for algorithmic developments in statistical learning, further theoretical study of why or when these techniques should work in practice on high dimensional data sets is still very much in demand. Ripley (1996) contains more theoretical discussions which should complement this book well, in addition to Vapnik’s (1999) far-reaching discussions. Ye (1998) is an important reference which I am surprised is not cited in Chapter 7. Another example is the notion of the curse of dimensionality which is central to motivating many of the multivariate regression techniques that are discussed in the book, but which is poorly explained in pages 22–23 of the book. The recent book by Clarke et al. (2009) gives more attention to this issue. Because multivariate data often lie in a low dimensional manifold, as alluded to in section 13.3.3 (pages 471–475), the hopeless situation of the curse of dimensionality as discussed in pages 22–23 of the book may not happen in many commonly encountered situations. Indeed, real problems are more promising, and I hope that statisticians realize that it may be more realistic to assume much more structure with multivariate data. An example is functional data, a framework in which the shape invariance considerations in section 13.1.3 should fit very well. When there is strong underlying dependence between covariates in a multivariate regression model so that the underlying probability measure for the covariates may not have a joint density function and may have a much lower (possibly fractal) intrinsic dimensionality than the number of covariates, Lu (1999) and Ferraty and Vieu (2000) demonstrate a much more auspicious statistical theory of high dimensional non-parametric regression. I am not a fan of big books and the second edition has become heavy on the hand with over 750 pages. I hope that the authors will seriously consider eliminating some repetitive material and trimming down a little in a future edition (such as removing most of Chapter 8 and Chapter 17). Despite my misgivings, I think that the new edition should continue to enjoy the success of its path breaking predecessor, as more people are attracted to learning about this important area in this information rich age.

ClassiJed by Test Individuals Positive Negative Total Known .ab a f b diseased False negatives Healthy or C d c+d control False positives From the National Bureau of Standards, Wash-

The interference of a discrete autoionized state with a continuum gives rise to characteristically asymmetric peaks in excitation spectra. The earlier qualitative interpretation of this phenomenon is extended and revised. A theoretical formula is fitted to the shape of the $2s2p^{1}P$ resonance of He observed in the inelastic scattering of electrons. The fitting determines the parameters of the $2s2p^{1}P$ resonance as follows: $E=60.1$ ev, $\ensuremath{\Gamma}\ensuremath{\sim}0.04$ ev, $f\ensuremath{\sim}2 \mathrm{to} 4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. The theory is extended to the interaction of one discrete level with two or more continua and of a set of discrete levels with one continuum. The theory can also give the position and intensity shifts produced in a Rydberg series of discrete levels by interaction with a level of another configuration. The connection with the nuclear theory of resonance scattering is indicated.

A description and justification of the EXPGUI program is presented. This program implements a graphical user interface and shell for the GSAS single-crystal and Rietveld package. Use of the Tcl/Tk scripting language allows EXPGUI to be platform independent. Also included is a synopsis of how the program is implemented.

The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years).\nAll five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules.\nThe HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition.

A Bose-Einstein condensate was produced in a vapor of rubidium-87 atoms that was confined by magnetic fields and evaporatively cooled. The condensate fraction first appeared near a temperature of 170 nanokelvin and a number density of 2.5 x 10(12) per cubic centimeter and could be preserved for more than 15 seconds. Three primary signatures of Bose-Einstein condensation were seen. (i) On top of a broad thermal velocity distribution, a narrow peak appeared that was centered at zero velocity. (ii) The fraction of the atoms that were in this low-velocity peak increased abruptly as the sample temperature was lowered. (iii) The peak exhibited a nonthermal, anisotropic velocity distribution expected of the minimum-energy quantum state of the magnetic trap in contrast to the isotropic, thermal velocity distribution observed in the broad uncondensed fraction.

We have observed a metallic solid (Al-14-at.%-Mn) with long-range orientational order, but with icosahedral point group symmetry, which is inconsistent with lattice translations. Its diffraction spots are as sharp as those of crystals but cannot be indexed to any Bravais lattice. The solid is metastable and forms from the melt by a first-order transition.

As one of the most successful applications of image analysis and understanding, face recognition has recently received significant attention, especially during the past several years. At least two reasons account for this trend: the first is the wide range of commercial and law enforcement applications, and the second is the availability of feasible technologies after 30 years of research. Even though current machine recognition systems have reached a certain level of maturity, their success is limited by the conditions imposed by many real applications. For example, recognition of face images acquired in an outdoor environment with changes in illumination and/or pose remains a largely unsolved problem. In other words, current systems are still far away from the capability of the human perception system.This paper provides an up-to-date critical survey of still- and video-based face recognition research. There are two underlying motivations for us to write this survey paper: the first is to provide an up-to-date review of the existing literature, and the second is to offer some insights into the studies of machine recognition of faces. To provide a comprehensive survey, we not only categorize existing recognition techniques but also present detailed descriptions of representative methods within each category. In addition, relevant topics such as psychophysical studies, system evaluation, and issues of illumination and pose variation are covered.

An approach for genome analysis based on sequencing and assembly of unselected pieces of DNA from the whole chromosome has been applied to obtain the complete nucleotide sequence (1,830,137 base pairs) of the genome from the bacterium Haemophilus influenzae Rd. This approach eliminates the need for initial mapping efforts and is therefore applicable to the vast array of microbial species for which genome maps are unavailable. The H. influenzae Rd genome sequence (Genome Sequence DataBase accession number L42023) represents the only complete genome sequence from a free-living organism.

This is an advanced text for higher degree materials science students and researchers concerned with the strength of highly brittle covalent–ionic solids, principally ceramics. It is a reconstructed and greatly expanded edition of a book first published in 1975. The book presents a unified continuum, microstructural and atomistic treatment of modern day fracture mechanics from a materials perspective. Particular attention is directed to the basic elements of bonding and microstructure that govern the intrinsic toughness of ceramics. These elements hold the key to the future of ceramics as high-technology materials - to make brittle solids strong, we must first understand what makes them weak. The underlying theme of the book is the fundamental Griffith energy-balance concept of crack propagation. The early chapters develop fracture mechanics from the traditional continuum perspective, with attention to linear and nonlinear crack-tip fields, equilibrium and non-equilibrium crack states. It then describes the atomic structure of sharp cracks, the topical subject of crack-microstructure interactions in ceramics, with special focus on the concepts of crack-tip shielding and crack-resistance curves, and finally deals with indentation fracture, flaws, and structural reliability.

Two of the most critical requirements in support of producing reliable face-recognition systems are a large database of facial images and a testing procedure to evaluate systems. The Face Recognition Technology (FERET) program has addressed both issues through the FERET database of facial images and the establishment of the FERET tests. To date, 14,126 images from 1,199 individuals are included in the FERET database, which is divided into development and sequestered portions of the database. In September 1996, the FERET program administered the third in a series of FERET face-recognition tests. The primary objectives of the third test were to 1) assess the state of the art, 2) identify future areas of research, and 3) measure algorithm performance.

International audience

A self-consistent real-space multiple-scattering (RSMS) approach for calculations of x-ray-absorption near-edge structure (XANES) is presented and implemented in an ab initio code applicable to arbitrary aperiodic or periodic systems. This approach yields a quantitative interpretation of XANES based on simultaneous, self-consistent-field (SCF) calculations of local electronic structure and x-ray absorption spectra, which include full multiple scattering from atoms within a small cluster and the contributions of high-order MS from scatterers outside that cluster. In addition, the code includes a SCF estimate of the Fermi energy and an account of orbital occupancy and charge transfer. We also present a qualitative, scattering-theoretic interpretation of XANES. Sample applications are presented for cubic BN, ${\mathrm{UF}}_{6},$ Pu hydrates, and distorted ${\mathrm{PbTiO}}_{3}.$ Limitations and various extensions are also discussed.

This book offers a concise introduction to the angular momentum, one of the most fundamental quantities in all of quantum mechanics. Beginning with the quantization of angular momentum, spin angular momentum, and the orbital angular momentum, the author goes on to discuss the Clebsch-Gordan coefficients for a two-component system. After developing the necessary mathematics, specifically spherical tensors and tensor operators, the author then investigates the 3-j, 6-j, and 9-j symbols. Throughout, the author provides practical applications to atomic, molecular, and nuclear physics. These include partial-wave expansions, the emission and absorption of particles, the proton and electron quadrupole moment, matrix element calculation in practice, and the properties of the symmetrical top molecule.

The index of refraction of optical quality fused silica (SiO2) was determined for 60 wavelengths from 0.21 to 3.71 μ at 20°C. The dispersion equation n2-1=0.6961663λ2λ2-(0.0684043)2+0.4079426λ2λ2-(0.1162414)2+0.8974794λ2λ2-(9.896161)2.where λ is expressed in microns was found to yield an absolute residual of 10.5×10−6. The variation in index between 12 specimens was determined. Dispersive properties of the material and thermal coefficient of index are graphically presented. A comparison with previous NBS index data is discussed.

An e valua ted compil ation of equilibrium rela ti ve humiditi es in a ir ve rsus tempe rature from pure phase to a pproximatel y l OS pascal (1 a tm) in press ure is present ed fo r 28 bina ry saturated aqueous so luti ons .Th e relative humiditi es of th e solutio ns ra nge from about 3 to 98 pe rcent.Us ing a da ta base from 2 1 sepa ra te in vesti gati ons compris ing 1106 indi vidu al meas ure me nts, fits we re made by the me thod of least s qua res to regula r po lynomia l equ ati ons with two through four coeffi c ie nts.Equa ti ons a nd ta bles a re presented a long with the estima ted uncert a inti es in the correla ted res ults.

Feshbach resonances are the essential tool to control the interaction between atoms in ultracold quantum gases. They have found numerous experimental applications, opening up the way to important breakthroughs. This review broadly covers the phenomenon of Feshbach resonances in ultracold gases and their main applications. This includes the theoretical background and models for the description of Feshbach resonances, the experimental methods to find and characterize the resonances, a discussion of the main properties of resonances in various atomic species and mixed atomic species systems, and an overview of key experiments with atomic Bose-Einstein condensates, degenerate Fermi gases, and ultracold molecules.

Rate constants have been compiled for reactions of various inorganic radicals produced by radiolysis or photolysis, as well as by other chemical means in aqueous solutions. Data are included for the reactions of ⋅CO2 −, CO3⋅−, O3, ⋅N3, ⋅NH2, ⋅NO2, NO3⋅, ⋅PO32−, PO4⋅2−, SO2⋅ −, ⋅SO3 −, SO4⋅−, SO5⋅−, SeO3⋅ −, (SCN)2⋅ −, CL2⋅−, Br2⋅ −, I2⋅ −, ClO2⋅, BrO2⋅, and miscellaneous related radicals, with inorganic and organic compounds.