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	Diffraction
		Diffraction effects arise from the interference between wavelets originating from a wavefront that is restricted by an aperture or blocked by an obstruction.
		This is a characteristic of Fraunhofer diffraction patterns and is further illustrated in the fourth applet.
		Patterns due to the aperture (smaller because of the wavelength change) are superimposed on the diffraction pattern due to the array.
	www.kw.igs.net /~jackord/df/d1.html (2026 words)

	X-Ray Diffraction Pattern
		X-ray diffraction occurs during the interaction of x-ray waves with a regular structure with repeat distances about the same as the wavelength of the x-ray.
		Patterns produced by an x-ray diffraction device are processed into charts detailing information like lambda (the wavelength of the x-ray), the theta value, and the d-spacing.
		On the correspondence of the small-angle and wide-angle x-ray diffraction patterns of wood fibers by Martti Kantola
	www.iscid.org /encyclopedia/X-Ray_Diffraction_Pattern (239 words)

	Diffraction - Wikipedia, the free encyclopedia
		Diffraction from multiple slits, as described above, is similar to what occurs when waves are scattered from a periodic structure, such as atoms in a crystal or rulings on a diffraction grating.
		Bragg diffraction is used in X-ray crystallography to deduce the structure of a crystal from the angles at which X-rays are diffracted from it.
		The most common demonstration of Bragg diffraction is the spectrum of colors seen reflected from a compact disc: the closely-spaced tracks on the surface of the disc form a diffraction grating, and the individual wavelengths of white light are diffracted at different angles from it, in accordance with Bragg's law.
	en.wikipedia.org /wiki/Diffraction (1784 words)

	[No title]
		Diffraction is the tendency of a wave emitted from a finite source or passing through a finite aperture to spread out as it propagates.
		Diffraction results from the interference of an infinite number of waves emitted by a continuous distribution of source points.
		Diffraction of light through a rectangular aperture is a rather straightforward extension of 1-dimensional diffraction from a slit, as shown in the diagram below.
	electron9.phys.utk.edu /optics421/modules/m5/Diffraction.htm (1561 words)

	Olympus Microscopy Resource Center: Light and Color - Diffraction of Light
		Diffraction of light occurs when a light wave passes by a corner or through an opening or slit that is physically the approximate size of, or even smaller than that light's wavelength.
		The amount of diffraction depends on the wavelength of light, with shorter wavelengths being diffracted at a greater angle than longer ones (in effect, blue and violet light are diffracted at a higher angle than is red light).
		Diffraction describes a specialized case of light scattering in which an object with regularly repeating features (such as a diffraction grating) produces an orderly diffraction of light in a diffraction pattern.
	www.olympusmicro.com /primer/lightandcolor/diffraction.html (1405 words)

	Diffraction Summary
		Diffraction is the deviation from a straight path that occurs when a wave such as light or sound passes around an obstacle or through an opening.
		The diffraction pattern of the telescope's circular mirror or lens is known as Airy's disk, which is seen as a bright central disk in the middle of a number of fainter rings.
		Diffraction is the bending, spreading and interference of waves when they pass by an obstruction or through a gap.
	www.bookrags.com /Diffraction (3160 words)

	DoITPoMS TLP - Diffraction and imaging - Diffraction 1
		Light from the laser (of wavelength l) is diffracted by a mask (usually a small aperture or grating) and projected onto the screen, located at a large distance away, such that Fraunhofer geometry applies.
		The operation that directly predicts the amplitude of the diffraction pattern from the mask is known as a Fourier Transform (provided the conditions for Fraunhofer Diffraction are satisfied).
		The diffraction pattern from a complex mask such as a grating can be constructed from simplier patterns via the convolution theorem.
	www.doitpoms.ac.uk /tlplib/DD1-6/diffraction1.php (266 words)

	Dispersion, Diffraction and Diffraction Gratings
		The analysis of the resulting diffraction pattern from a single slit is similar to what we did for the double slit.
		The shape of the diffraction pattern is determined by the width (W) of the slits, while the shape of the interference pattern is determined by d, the distance between the slits.
		For a diffraction grating, then, with a large number of slits, the pattern is sharp because of all the destructive interference taking place between the bright peaks where constructive interference takes place.
	physics.bu.edu /py106/notes/Diffraction.html (1128 words)

	[No title] (Site not responding. Last check: 2007-10-10)
		The diffraction patterns of bone samples are characterized by a quite intense background that shows a marked halo at 2 15°.
		In the case of such simple LEED patterns, it is possible to explain the diffraction pattern in terms of scattering from rows of atoms on the surface.
		When a microscope objective forms a diffraction-limited image of an object, it produces a three-dimensional diffraction pattern that is periodic both along the optical axis (the z-axis) and laterally (the x- and y-axes) in the intermediate image plane.
	www.lycos.com /info/diffraction--diffraction-patterns.html (459 words)

	X-ray, Neutron, and Electron Simulation in MOE (Site not responding. Last check: 2007-10-10)
		Diffraction pattern analysis plays an important role in such divers applications as solving molecular structures, identifying compounds, and the fabrication of materials.
		The diffraction pattern generated from a single crystal is an array of sharp spots.
		Although, in theory, a diffraction pattern is a projection of the weighted crystal reciprocal lattice, in practice, the observed pattern is more complex, being affected by many factors including experimental setup, thermal vibration of the atoms in the crystal, internal reflections which cause interference, and so forth.
	www.chemcomp.com /feature/diffr.htm (1615 words)

	Laser Diffraction \| Mie Scattering Theory
		The pattern of lines is related to the wavelength of the illuminating light and the distance between the slits.
		The equation also established the concept of interference patterns that was used by Bragg to experimentally verify the concept of diffraction (bending) of light from layers of atoms in a crystal.
		Diffraction of light occurs at the edge of particles, but many substances have particles that are transparent and allow light to pass though.
	www.microtrac.com /laserdiffraction.cfm (1333 words)

	Mathcad Library
		Students record the diffraction pattern (using paper and pencil), index the pattern, calculate the dimensions o f the unit cell, and then select their pattern from a group of 8 possible ones.
		Record the diffraction pattern, distances between spots, angles, etc. (I would suggest that this be done be drawing the pattern produced and putting in measured distances.
		The horizontal distribution of the diffraction pattern will be produced by spacing between vertical rows on the diffraction pattern and will there for correspond to x-axis spacing or h indices.
	www.mathcad.com /library/LibraryContent/MathML/diffraction.htm (514 words)

	Fraunhofer Diffraction (Site not responding. Last check: 2007-10-10)
		The diffraction pattern at the right is taken with a helium-neon laser and a narrow single slit.
		These single slit diffraction patterns were photographed with a helium-neon laser as the light source and a micrometer-controlled single slit.
		The sketches of the slit widths at right were scaled to the difference between the first minima of the diffraction patterns.
	hyperphysics.phy-astr.gsu.edu /hbase/phyopt/fraungeo.html (98 words)

	diffraction
		Notice that as the pattern of the stocking is stretched larger, the diffraction pattern becomes smaller in the direction of the stretch
		The spacing of the changes in an object pattern is inversely related to the spacing of the changes in the diffraction pattern.
		The diffraction pattern on a distant screen is the two dimensional spatial fourier transform of the original object pattern.
	www.exo.net /~pauld/activities/lasers/laserdiffraction.htm (496 words)

	DoITPoMS TLP - Indexing Diffraction Patterns
		The diffraction spots are produced directly from the electron beam, which either hits or misses the Bragg angle for each plane; so the spot is either present or absent depending on the orientation of the crystal.
		Using the image to verify that the double dots in the diffraction pattern are being caused by the two crystal structures either side of the twin boundary, we can index the pattern and determine the twin plane and the crystal structures either side of it.
		Other reflections in the electron diffraction pattern can then be deduced from simple vector addition, with the proviso that the indices of the reciprocal lattice vectors are integers and that they are not forbidden by the lattice.
	www.msm.cam.ac.uk /doitpoms/tlplib/diffraction-patterns/printall.php (3196 words)

	Sarcomere Length Measurements
		The grating equation for light diffraction states that for the diffraction pattern that forms when light is passed through an array of regularly spaced openings, that the diffraction order number (n) times the wavelength of the light (λ;) is equal to the distance between slits (d) times the sine of the diffraction angle (λ), or:
		Because the diffraction angle (θ) is difficult to measure, it is easier to mathematically derive it.
		The diffraction technique exploits the fact that coherent laser light constructively interferes with the normal skeletal muscle striation pattern formed by the interdigitation of actin and myosin contractile filaments.
	muscle.ucsd.edu /musintro/diffraction.shtml (578 words)

	Melles Griot Optics Guide - Diffraction (Site not responding. Last check: 2007-10-10)
		Fresnel diffraction is primarily concerned with what happens to light in the immediate neighborhood of a diffracting object or aperture.
		The irradiance distribution in the diffraction pattern of a uniformly illuminated slit aperture is described by
		Apodization, or nonuniformity of aperture irradiance, alters diffraction patterns.
	www.mellesgriot.com /products/optics/fo_3_1.htm (947 words)

	Exploratorium: Science Snacks: Diffraction
		The diffraction pattern, the pattern of dark and light created when light bends around an edge or edges, shows that light has wavelike properties.
		In fact, the angle between two adjacent dark bands in the diffraction pattern is inversely proportional to the width of the slit.
		A piece of cloth or a feather, which are both made up of many smaller, thinner parts, produce complicated diffraction patterns.
	www.exploratorium.edu /snacks/diffraction.html (864 words)

	6.2 Low Energy Electron Diffraction ( LEED )
		Only the elastically-scattered electrons contribute to the diffraction pattern ; the lower energy (secondary) electrons are removed by energy-filtering grids placed in front of the fluorescent screen that is employed to display the pattern.
		The pattern shows the same rectangular symmetry as the substrate surface but is "stretched" in the opposite sense to the real space structure due to the reciprocal dependence upon the lattice parameter.
		The pattern is also centrosymmetric about the (00) beam - this is the central spot in the diffraction pattern corresponding to the beam that is diffracted back exactly normal to the surface (i.e.
	www.chem.qmul.ac.uk /surfaces/scc/scat6_2.htm (1391 words)

	Diffraction and interference
		Reflection, refraction, diffraction, and interference are phenomena observed with all waves.
		For 4 slits, there are three positions, for 5 slits there are four positions, etc. For a diffraction grating with a large number of slits, the pattern is sharp because of the many positions of completely destructive interference between the bright, constructive-interference fringes.
		The spectral pattern is repeated on either side of the main pattern.
	electron9.phys.utk.edu /phys136d/modules/m9/diff.htm (1293 words)

	[No title]
		The corona is the diffraction pattern seen in cloud droplets when looking towards the sun, the glory is the diffraction pattern seen in cloud or fog droplets when looking toward the antisolar point.
		As in other diffraction rings the blue halo is on the inside and the red on the outside.
		If there is a wide mixture of droplets of varying size then the diffraction rings will be of widely varying size, overlapping each other and blurring into a uniform illumination, leaving only the aureole visible.
	www.lycos.com /info/diffraction--light.html (493 words)

	X-Ray Powder Diffraction
		X-ray diffraction has been in use in two main areas, for the fingerprint characterization of crystalline materials and the determination of their structure.
		The diffraction pattern of copper metal was measured with x-ray radiation of wavelength of 1.315Å.
		The diffracted beam may be detected by using a moveable detector such as a Geiger counter, which is connected to a chart recorder.
	materials.binghamton.edu /labs/xray/xray.html (774 words)

	Surface Diffraction and the Reciprocal Lattice
		Unfortunately, the diffraction pattern is not a direct representation of the real-space arrangement of the atoms in a solid or on a surface.
		The angle of diffraction of the wave-particle is governed by the Bragg equation.
		It is possible to think of surface diffraction in terms of rows of atoms and draw a qualitative picture of the diffraction pattern merely by considering the spacing of these rows.
	www.cem.msu.edu /~cem924sg/Reciprocal.html (942 words)

	index.html
		The transision to scalar diffraction is made by saying "well, if the aperture from which we're diffracting is large, the effects of the boundary conditions at the edge of the aperture will be small and won't differ with the polarization of the dipole." This, then, is the basis behind Huygen's principle.
		The diffraction pattern of an arbitrary aperture can be approximated very quickly and yet accurately by computing the numerical approximation of the spatial convolution of the above kernel with the aperture.
		With the Fraunhofer approximation, diffraction is treated as a linear system with an impulse response characterized by some static kernel multiplied by a complex exponential with a linear phase proportional to the shift.
	www.mit.edu /~birge/diffraction (1772 words)

	Diffraction Lab (Site not responding. Last check: 2007-10-10)
		Diffraction of a wave by a periodic array is due to phase differences that result in constructive and destructive interference (illustrated in Figure 1).
		Observation of diffraction patterns when beams of electrons, neutrons, or X-rays pass through crystalline solids thus serves as evidence both for the wave nature of those beams and for the periodic nature of the crystalline solids.
		In this experiment, you will first check how the size and orientation of the diffraction pattern is related to the periodic array that produced it, and then you will measure distances in diffraction pattern spacings in order to calculate the repeat distance for the array in the slide.
	people.uis.edu /kdung1/che422/diffraction.htm (1132 words)

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