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This chapter presents Reich's spontaneous reaction to the film “Wavelength” by Michael Snow. It was not published until it was included in the catalogue for a retrospective exhibition of Michael Snow's work: Presence and Absence-Films of Michael Snow, edited by Jim Shedden.

This chapter reviews the recent development of near-field biomolecule imaging systems. Near-field scanning optical microscopy (NSOM) offers a practical means of optical imaging at a resolution well beyond the diffraction limit of light. Applications are limited, however, due to strong attenuation of transmitted light through the sub-wavelength aperture. A variety of approaches to address this problem, such as apertureless NSOM and plasmonic near-field focusing devices, are covered in this chapter. These approaches provide an enhanced nanoscale imaging tool for cellular visualization, single molecule detection, and many other applications requiring high spatial and temporal resolution.

From a relatively small beginning, nearly two decades ago, phase calculation using multiple-wavelength anomalous diffraction (MAD) data has become more widespread and generally used. This chapter discusses the most recent developments and experimental details. Topics covered include the theoretical background of MAD phasing and some of the choices that need to be made in the design and implementation of MAD experiments.

This chapter describes the steps required to carry out the two-stage phasing process for proteins and illustrates these through the application of BnP program to the multiple-wavelength anomalous dispersion (MAD) data set for the selenomethionine derivative of methylmalonyl-coenzyme A epimerase from Propionibacterium shermanii. The BnP program has two operational modes, automatic and manual. In automatic mode, which is geared to routine high-throughput applications, the user needs only to specify a few parameters, and the entire two-stage phasing process from substructure determination through phase refinement and solvent flattening is chained together and started by clicking a single button. On the other hand, manual mode is available for large structures or difficult problems with marginal data, and it allows the user to control many parameters and to execute the major steps in the phasing process sequentially.

This chapter examines the genetic mechanisms responsible for the difference in long-wave (L) and middle-wave (M) cone ratio between monkeys and humans. It is possible that sequences of the L and M gene promoter regions influence the L versus M cone decision-making process during development. The similarity between the L and M promoters in Old World monkeys may be related to the nearly equal numbers of L and M cones in these animals, and that some of the additional differences between the human L and M promoters may play a role in producing the difference in L and M cone numbers in human retinas. It is also possible that other differences between L and M genes, for example differences within the introns, may play a role in determining the L:M ratio.

This chapter discusses how there are four general factors that contribute to the Sun's potential role in variations in the Earth's climate. First, the fusion processes in the solar core determine the solar luminosity and hence the base level of radiation impinging on the Earth. Second, the presence of the solar magnetic field leads to radiation at ultraviolet (UV), extreme ultraviolet (EUV), and X-ray wavelengths which can affect certain layers of the atmosphere. Third, the variability of the magnetic field over a 22-year cycle leads to significant changes in the radiative output at some wavelengths. Finally, the interplanetary manifestation of the outer solar atmosphere (the solar wind) interacts with the terrestrial magnetic field, leading to effects commonly called space weather.

This chapter presents the properties of thermal neutrons. Their wavelength (from the de Broglie equation) is well suited to the investigation of condensed matter, i.e., to the study of liquids, glasses (amorphous materials), and crystalline materials with varying degrees of order. That the neutrons carry magnetic moment also makes them well suited to the study of magnetic ordering. The theory of nuclear and magnetic scattering from individual atoms and from assemblies of atoms is presented, this leading to the definition of neutron scattering length and to the concepts of coherent and incoherent scattering. The focus then shifts to the direction and intensity of diffraction from crystalline materials (Bragg's law, structure factors), and to the description of this scattering when samples are presented in polycrystalline or powder form (Debye-Scherrer cones).

This chapter first gives the location of facilities for neutron powder diffraction. Constant wavelength (CW) and time-of-flight (TOF) diffractometers are introduced. The typical components (monochromators, collimators, neutron detectors) are described in some detail and a comparison of CW with TOF instruments is presented. The chapter includes advice on planning and executing measurements by neutron powder diffraction, as well as detail on the important matter of sample environment, that is, the furnaces, cryostats, pressure cells, electrochemical cells, etc., that the experiments might involve. Sample preparation is also a matter that demands quite careful attention, so important considerations are presented.

This chapter covers the rudiments of quantum theory, including the dual nature of light and matter, the Uncertainty Principle and probability concept, the electronic wavefunction, and the probability density function. Numerical examples are given to show that given the electronic wavefunction of a system, the probability of finding an electron in a volume element around a certain point in space can be readily calculated. Finally, the electronic wave equation, the Schrödinger equation, is introduced. This discussion is followed by the solution of a few particle-in-a-box problems, with the ‘box’ having the shape of a wire (one-dimensional), a cube, a ring, or a triangle. Where possible, the solutions of these problems are then applied to a chemical system.

This chapter discusses the electron wavelength, relativistic effects, ray diagram for a typical electron microscope, simple electron optics theory and approximations for ideal lenses. The constant field approximation, projector lenses, objective lenses, lens design, aberrations and the pre-field are also covered.

This chapter explores units and geometry in light measurement. For biologists not working on humans, it comes down to a few simple rules: use photons not watts; use wavelength not frequency, but be extremely careful when comparing the peaks of light spectra to sensitivity curves; stick to measuring radiance and irradiance, but be a pioneer and add scalar irradiance measurements to your papers; irradiance sometimes obeys the inverse-square law; radiance rarely does; do not use photometric units, except possibly for lux. However, the underlying principle of weighted integrals is useful for modeling animal vision and other wavelength-dependent processes.

This chapter derives the general solution for the electric and magnetic fields emitted by an accelerated relativistic charged particle using Maxwell’s equations as the starting point. This general solution is then applied to the case of a bending magnet and the photon flux and brightness levels found. Finally, it is shown that by using a special magnet called a wavelength shifter, it is possible to alter the output spectrum significantly to enhance the output at X-ray wavelengths.

This chapter uses simple interference arguments to derive the undulator wavelength equation and then explains why odd harmonics are dominant in such a device. The flux distribution is then found followed by the polarization characteristics. Additional properties that are explained, with the use of examples, are the output brightness, coherence, and the impact of near field effects.

This chapter discusses the construction of undulators and wigglers using electromagnets and compares their performance with those of permanent magnets. Alternative magnet geometries are examined such as planar, elliptical, and helical. In the last section, the application of superconducting magnets is examined and the advantages when applied to wavelength shifters, wigglers, and undulators are highlighted.

This chapter presents the basic aspects of the microscopic description of fluctuation phenomena in superconductors. The notion of fluctuation propagator as the vertex part of the electron: electron interaction in the Cooper channel, diagrammatic representation of fluctuation corrections, the method of their averaging over impurities, are introduced. The developed method of Matsubara temperature Green's functions applied to a description of the fluctuations allows the determination of the values of the phenomenological parameters of the GL theory. It also allows the determination of the treatment of fluctuation effects quantitatively, even far from the transition point, and for strong magnetic fields taking into account the contributions of dynamical and short wavelength fluctuations, as well as the quantum effects eluding from the phenomenological consideration.

This chapter analyzes the collection of data on a modern area-detector diffractometer, with respect to the contributory factors: characteristics of the X-ray detector, choice of radiation appropriate to the sample, temperature, pressure, and other conditions. The various kinds of detector system are reviewed, with their advantages and disadvantages, and CCD (charge-coupled device) detectors are described in more detail, including the necessary corrections for spatial and intensity distortions and background dark current effects. Methods of screening samples with X-rays are described, and consideration given to practical aspects of obtaining unit cell and orientation information, with advice for difficult cases. Data collection parameters and characteristics affecting speed and quality include the general level of diffraction intensity, crystal mosaicity, symmetry, and the use of low-temperature devices.

Crystal structure determination by diffraction uses X-rays or neutrons. X-rays are readily available in laboratories from a standard X-ray tube, in which electron kinetic energy is converted to X-rays by interaction with core electrons of a metal target, giving particular characteristic wavelengths (and much wasted heat). Enhancements of the basic X-ray tube include rotating anodes and microfocus tubes, and the extracted X-rays can be concentrated somewhat by modern optics methods. Far higher X-ray intensities, together with other special properties, are obtained from synchrotron storage rings, which are large-scale national and international facilities; some of the properties are described, and an account given of applications. Neutrons are available from nuclear reactors and spallation sources, in monochromatic or pulsed polychromatic modes. Some advantages and disadvantages of neutrons, compared with X-rays, are described, resulting from their different interaction with samples.

Since the aberrations of the lens are negligible, the resolution of the acoustic microscope is essentially limited by diffraction. If the lens has a high numerical aperture the resolution is comparable with the acoustic wavelength. The smallest wavelength which can be used is determined by attenuation in the coupling fluid, which generally varies as the square of the frequency. Of all the candidate fluids, one of the best is warm water, which has low attenuation and offers good coupling to the elastic properties of most samples. Superfluid helium offers lower attenuation, and a grating of period 200 nm has been imaged at 15.3 GHz, but for most practical purposes water is used.

Surface cracks and boundaries give contrast in acoustic microscopy even when they are so fine that by conventional resolution criteria they would be expected to be scarcely visible. The contrast arises from the scattering of Rayleigh waves, and the evidence for this is the tell‐tale presence of fringes parallel to cracks, with spacing equal to half a Rayleigh wavelength. Contrast theory based on separating the specular and Rayleigh components of the signal give a good account of the fringes which are observed. Time‐resolved measurements can be made of crack‐tip diffracted signals. The remarkable contrast from cracks is useful in the study of indentation and fracture of low‐ductility materials.

This 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.