Zones alternate between opaque and transparent, and are spaced so that light transmitted by the transparent zones constructively interferes at the desired focus. Home zone plate it is an interesting optical device, constructed on the basis of fresnel half period hypothesis, which proves rectilinear propagation of light. Then have them reread to identify observations that the theory of plate tectonics explains. These boundaries are places where two plates are pushing toward, pulling away, or sliding past each other. Plate tectonics grew out of a theory that was first developed in the early 20th century by the meteorologist alfred wegener in 1912 he noticed that the coastlines of the east coast of south america and the west coast of africa appeared to fit together like jigsaw pieces.
The earth is composed of layers of different composition and physical properties, principally the solid central core, the fluid peripheral core, the viscous mantle, and the solid. Plates are defined as plane structural elements with a small thickness compared to the planar dimensions. Diffraction theory for azimuthally structured fresnel zone plate. Introduction to plate tectonic theory, geodesy, and vlbi. The most important lesson from 83,000 brain scans daniel amen tedxorangecoast duration. Earths geography has changed through time and continues to change today. Dec 31, 2017 the most important lesson from 83,000 brain scans daniel amen tedxorangecoast duration. When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around earths surface. Learn about zone locations, resolution, bandwidth restrictions, and field of view.
Depending on your choice of units, the small box is either 10 mm 1 cm or 14 inch wide and tall, the medium box either 20 mm 2 cm or 12 inch, the large box is either 30 mm 1 cm or 1 inch 25. Zone plate article about zone plate by the free dictionary. The theory of plate tectonics geology lumen learning. Balch division of mechanics and computation department of mecanical engineering stanford university stretching and bending of plates fundamentals introduction a plate is a structural element which is thin and. Transmission zone plates composed of materials describable by the complex index of refraction nn 1. Plate tectonics have students team read pages 158 and 159 to. Scale the zone plate by entering a multiplier for the scale value, save and print the zoneplate, then take a picture of the print. This is cool from a theoretical point of view, because it demonstrates the wave nature of light. Oceanic trenches at oceanocean subduction zones are the.
Diffraction theory of fresnel zone plates henri arsenault author information. And its cool from a photography point of view, because the images produced have a unique glow, with an impressionistic almostpainted look. Stress distribution through the thickness of a plate and resultant bending moment plate theory and beam theory. Introduction to plate tectonics theory geography tutor2u. Along the way, i disclose details of what real science is all about, details all too often absent in textbooks and classroom discussions. Zone plate is a specially constructed diffraction screen in the form of transparent glass plate in which alternate zones are cut off. Outline of a variational formulation of zoneplate theory. Bandbroadening is a general term used to describe the overall dispersion or widening of a sample peak as it. The constantthickness zone plate as a variational solution. The beauty within a zone plate image is the recognizable halo or. An easytouse zone plate generator calculator that creates zone plate gds files to match the wavelength, imaging conjugates, and constraints that the user provides.
The thickness is usually constant but may be variable and is measured normal to the middle surface of the plate, fig. A tectonic plate boundary where two plates collide, come together, or crash into each other. For that reason the use of diffractive lenses is interesting 1. However, light through a lens undergoes refraction but light through a zone plate undergoes diffraction. All this process describes how to derive the elastic equations for. The first book devoted solely to fresnel zones in microwavemmwave electromagnetics, this comprehensive survey covers theory, design and practical applications. If the plate odd zones are transparent then it is called positive zone plate and when even zones are transparent it is called negative zone plate as shown in figure 5.
Multiply the factor the image was scaled up by the focal length of the camera lens. In general, exact solutions for cantilever plates using plate theory are quite involved and few exact solutions can be found in the literature. Diffraction from fresnel zone plates school of physics. A zone plate is a diffractive optic that consists of several radially symmetric rings called zones. Plates move apart at midocean ridges where new seafloor forms. Pdf fresnal zones in wireless links, zone plate lenses and. Forms mountain ranges, often with volcanoes, island arcs andor deep ocean trenches. The spatial resolution of a fresnel zone plate depends, according to the abbe theory, on the numerical entrance aperture na e, zp of the zone plate, with the refractive index decrement n material real part of the refractive index n of the medium between the object and the zone plate, the entrance acceptance angle of the zone plate and the. One of the differences between plane stress and plate theory is that in the plate theory the stress components are allowed to vary through the thickness of the plate, so that there can be bending moments, fig.
The use of a fresnel zone plate as a coded aperture for imaging incoherent radiation such as gamma rays has been previously reported. Fresnel zone plate a circular aperture in which alternate rings are transparent and opaque is called a fresnel zone plate. Pdf a zone plate composed of mo zones having 4 mm outermost zone diameter, 100 nm outermost zone. The variational problem, as formulated here, is shown to generate some important classical zone plate configurations as special solutions and to lead naturally to the derivation of the most general zone plate configurations possible.
Published by the american geophysical union as part of the geodynamics series, volume 30. Twisting the plate will raise the medial longitudinal arch, plantarflex the first ray, decrease strain on the medial central band of the plantar aponeurosis, and decompress and improve rom of the 1st mtp. Note also that for the analysis in this letter, the entire effect of the zone plate geometry is represented by the parameter hr, which is the thickness of the material presented to the light at radius r. Like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics. Some specific optimum solutions are derived for gold in the soft xray range and tabulated for convenient reference. Continental drift, sea floor spreading and plate tectonics. Scalar diffraction theory for azimuthally structured. It is more plastic than the lithosphere so it is easier to bend and move. The theory of plate tectonics proposes that the lithosphere is divided into a series of plates that fit together like the pieces of a jigsaw puzzle. Applying the twisted plate theory of foot stability to. A conventional fresnel zone plate fzp consists of concentric rings with an alternating binary transmission of zero and one. Since the development of the theory, geologists have had to reexamine almost every aspect of. Strain builds up along plate boundaries, and when the strain becomes too great, fractures form and.
The theory has caused a revolution in the way we think about the earth. Let s is the source, p is the point of observation and xy is the edge. An important change in ideas about plate tectonics has been the recognition that the boundaries between plates are often broad zones of deformation, rather than the narrow boundaries originally assumed in plate tectonic theory. Trench systems occur for both continentocean and oceanocean boundaries the worlds deepest parts of the ocean are found along trenches.
The coded image is in many respects similar to a hologram and can be decoded or reconstructed with a coherent optical system. For example, scale up a zone plate up by a factor of 400 in a photo editor and print it. Thin plate b smallest side thick plate t 20 b 2000 1 10 1. Stateoftheart sub 20 nm fresnel zone plate fzp optics for xray focusing and microscopy applications, including phase contrast, ptychography, and. The approach is a generalization of the onedimensional euler bernoulli beam theory, which exploits the slender shape of a beam. May 08, 2012 the classical fresnel zone plate fzp is in theory a good solution but the individual rings need to be hold in place. Unlike lenses or curved mirrors however, zone plates use diffraction instead of refraction or reflection. A zone plate is used for focusing light, like a lens. The classical fresnel zone plate fzp is in theory a good solution but the individual rings need to be hold in place. A plate with alternate transparent and opaque rings, designed to block off every other fresnel halfperiod zone. The structure of the earth, plate tectonics and landforms. This theory demands that the radii of the rings differ by an optical path of n. Sep 24, 2017 a zone plate is used for focusing light, like a lens.
The focal length l is measured in units of numbers of wavelengths. California, berkeley zone plate microscopy and applications, ee290f, 12 april 2007. Also sold as part of a 4 pack item with same title. The effects of various system parameters such as the. Pdf fresnal zones in wireless links, zone plate lenses. Good companion to a textbook chapter on plate tectonics. An alternative is given in 2 but to keep the main structure of an fzp one can use bridges which connect the rings to each other. Simulation of highresolution xray zone plates xray optics and.
Lithosphere is divided into plates that slide around on top of the slowly moving mesosphere tectonic plates it occurred after the breakup of pangaea, and since then the continents have drifted apart the pictures show continental drift theory from 225 million years to present. Bandbroadening is a general term used to describe the overall dispersion or widening of a sample peak as it passes through a separation system. This zone where a plate is diving back down into the mantle, beneath the edge of the adjacent plate, is called a subduction zone. The typical thickness to width ratio of a plate structure is less than 0.
Let s is the source, p is the point of observation and xy is the edge wise section zone plate as shown in figure 5. A zone plate is a device used to focus light or other things exhibiting wave character. This is based on the principle of fresnel lenses and so is known as fresnel zone plate. Fresnel zone plate theory, generation, tolerancing. For a plane wave normally incident upon a zone plate, the diffracted light will be concentrated at the focal points along the optical axis. Continental drift, sea floor spreading and plate tectonics plate tectonics is a theory developed in the late 1960s, to explain how the outer layers of the earth move and deform. Pdf diffraction theory for azimuthally structured fresnel zone plate. The theory of plate tectonics helps explain this pattern because the earthquake and volcano belts mark the locations of plate boundaries. The twisted plate theory of foot stability key point. The twodimensional plate theories can be classified into two types. Pdf characterization of zone plate properties using. A zone plate is a way of focusing light, like a lens, but using fresnel diffraction instead of refraction. L1 advanced readers plate motions point out that the arrows in figure 20 show the direction of plate motion.
The type of plate boundary and the type of crust found on each side of the boundary determines what sort of geologic activity will be found there. Whether you are an experienced electromagnetics specialist or a newcomer to the field, whether you need practical design guidelines or a clear and concise exposition of the fundamentals, youll find this book. Complementary zone plates as shown in figure 2 give the same diffraction pattern. Although plate tectonics is a relatively young idea in comparison with unifying theories from other sciences e. Diffraction theory for azimuthally structured fesnel zone plate has been studied by t. Pdf diffraction theory of fresnel zone plates henri.
The lithosphere lithosphere is comprised of the upper mantle and the crust, the outer shell of the earth. Hence, although it used to be common to straddle the san andreas fault and. The san andreas fault zone in california is an example of what kind of plate boundary. Scalar diffraction theory for azimuthally structured fresnel. To construct a zone plate number of concentric circles with the radii proportional to square root of natural numbers are drawn on a paper. In continuum mechanics, plate theories are mathematical descriptions of the mechanics of flat plates that draws on the theory of beams. Ret 2006, rev 2 7 introduction to plate tectonic theory, geodesy, and vlbi the plate tectonic theory is a relatively new, accepted only around 50 years ago.
In this paper, the general theory of codedaperture imaging is presented, first for an arbitrary code and then for an onaxis zone plate. Based on analysis by augustinjean fresnel, they are sometimes called fresnel zone plates in his honor. The firstorder shear deformation plate theory fsdpt, described in detail in chapter 4, is an extension of the wellknown timoshenko beam theory andor the mindlinreissner plate theory that is applied to laminated composite plates. An alternative is given in 2 but to keep the main structure of an fzp one can use bridges which connect the rings to. The thickness h is much smaller than the typical plate dimension, h. The subducting plate is bent downward to form a very deep depression in the ocean floor called a trench.
L is the distance from the zone plate center to the point of observation. Circle the letter of the type of plate boundary that occurs when a plate of continental crust grinds past another plate of continental crust. Reissner and stein 5 provide a simplified theory for cantilever plates that is an improvement over older theories such as saintvenant plate theory. The kirchhoff classical plate theory cpt for the pure bending case is based on the displacement field. Introduction to the theory of plates stanford university. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This is the size of the black box surrounding the zone plate. Xray zone plates the highest quality xray optics with proven resolution, efficiency and reliability at low costs for soft and hard xrays for ptychography, stxm, txm and phase contrast imaging. Jahns of germany 27 where they have studied the light transmission from concentric rings with.