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This chapter discusses atomic force microscopy (AFM), focusing on the methods for atomic force detection. Although the force detection always requires a cantilever, there are two types of modes: the static mode and the dynamic mode. The general design and the typical method of manufacturing of the cantilevers are discussed. Two popular methods of static force detection are presented. The popular dynamic-force detection method, the tapping mode is described, especially the methods in liquids. The non-contact AFM, which has achieved atomic resolution in the weak attractive force regime, is discussed in detail. An elementary and transparent analysis of the principles, including the frequency shift, the second harmonics, and the average tunneling current, is presented. It requires only Newton's equation and Fourier analysis, and the final results are analyzed over the entire range of vibrational amplitude. The implementation is briefly discussed.

This chapter discusses atomic force microscopy (AFM), focusing on the methods for atomic force detection. Although the force detection always requires a cantilever, there are two types of modes: the static mode and the dynamic mode. The general design and the typical method of manufacturing of the cantilevers are discussed. Two popular methods of static force detection are presented. The popular dynamic-force detection method, the tapping mode is described, especially the methods in liquids. The non-contact AFM, which has achieved atomic resolution in the weak attractive force regime, is discussed in detail. An elementary and transparent analysis of the principles, including the frequency shift, the second harmonics, and the average tunneling current, is presented. It requires only Newton’s equation and Fourier analysis, and the final results are analyzed over the entire range of vibrational amplitude. The implementation is briefly discussed.

There are numerous observations of the spectral attenuation, absorption, and scattering of distilled water and seawater. Morel (1974) reviewed the literature with respect to the attenuation coefficient as a function of wavelength and published his seawater and distilled water scattering coefficients. Smith and Baker (1978b) critically reviewed measurements made by many investigators to estimate the relative accuracies in the published values for the total absorption coefficient and the diffuse attenuation coefficient, and found a large range. Early workers frequently did not make a careful distinction between the absorption coefficient, the diffuse attenuation coefficient, and the total beam attenuation coefficient. Preisendorfer (1976) derived a set of inequalities linking the total beam attenuation coefficient, the diffuse attenuation coefficient, the forward scattering coefficient, the average cosine, the backscattering coefficient, and the absorption coefficient. This treatment allows us to define the theoretical bounds for the inherent and apparent optical properties of optically pure water. Morel (1974) defined optically pure water as a medium devoid of dissolved and suspended material. Thus, optically pure water is a medium for which particle backscattering, particle absorption, and the absorption due to dissolved organic material are zero, so the attenuation due to the water is the absorption due to water plus molecular scattering; that is, . . . cw = aw+bm (12.1) . . . Using the relationship (Preisendorfer, 1976) one can derive an inequality for the fresh water diffuse attenuation coefficient, establishing the following limitation (in the absence of transpectral scattering): where one-half the molecular scattering is included since molecular scattering is isotropic.

Under the neo-Darwinian theory, selection is the potter and variation is the clay: peculiarities or regularities of variation may emerge from internal causes, but these are ultimately irrelevant, because selection governs the outcome of evolution. Chapter 6 addresses this sense of “randomness” as irrelevance or unimportance, featuring (1) an analogical-metaphysical argument in which mutation is equated with raw materials or fuel, or is said to act at the “wrong level” to be an evolutionary cause; (2) direct empirical arguments; (3) mechanistic claims, e.g., claims about the ability of the “gene pool” to maintain variation, or of selection to be creative; (4) methodological claims to the effect that selection is amenable to study, but not mutation; and (5) an explanatory claim to the effect that mutation, though perhaps influential, only affects the boring parts of evolution. Appendix D provides quotations on the theme of unimportance.