Point source

The VIGRAL approach represents the reflecting surface of a defect as an ensemble of virtual point sources. At every measurement point of the B-Scan, the detecting transducer responds... 

Under ideal conditions (e.g., point sources producing spherical waves and no multiple reflections) a rectified backscattered signal represents line integrals of the ultrasonic reflectivity over concentric arcs centered at the transducer position. To reconstruct the reflection tomo-... 

The field radiated into the coupling medium by such a distribution of sources may be obtained by means of the well-known Rayleigh integral. The field at the considered point r is computed by a simple integral over the whole radiating surface of the contributions of each elementary source acting as a hemispherical point source. 

The diffraction pattern observed in LEED is one of the most connnonly used fingerprints of a surface structure. Witii XRD or other non-electron diffraction methods, there is no convenient detector tliat images in real time the corresponding diffraction pattern. Point-source methods, like PD, do not produce a convenient spot pattern, but a diffrise diffraction pattern that does not simply reflect the long-range ordermg. 

Existing methods for monitoring the transport of gases were inadequate for studying aerosols. To solve the problem, qualitative and quantitative information were needed to determine the sources of pollutants and their net contribution to the total dry deposition at a given location. Eventually the methods developed in this study could be used to evaluate models that estimate the contributions of point sources of pollution to the level of pollution at designated locations. 

Soft x-rays with wavelengths of 1—10 nm ate used for scanning x-ray microscopy. A zone plate is used to focus the x-ray beam to a diameter of a few tens of nanometers. This parameter fixes and limits the resolution. Holographic x-ray microscopy also utilizes soft x-rays with photoresist as detector. With a strong source of x-rays, eg, synchrotron, resolution is in the 5—20-nm range. Shadow projection x-ray microscopy is a commercially estabflshed method. The sample, a thin film or thin section, is placed very close to a point source of x-rays. The "shadow" is projected onto a detector, usually photographic film. The spot size is usually about 1 ]lni in diameter, hence the resolution cannot be better than that. 

Pipelines (qv) connect these large EOR projects to natural CO2 sources in Colorado and New Mexico. Industrial point sources of CO2 have also been used for projects in other areas. 

Part 403 general pretreatment regulations for existing and new sources of pollution Part 411 cement manufacturing point source category Part 413 electroplating point source category... 

Part 415 inorganic chemicals manufacturing point source category... 

Development Documentfor Effluent Eimitations Guidelines and Standards for the Inorganic Chemicals Manufacturing, Point Source Category (proposed), EPA Pubhcation 440/1-79/007, Washington, D.C., June 1990. 

The material vaporized from a small area (point source) leaves the surface with a cosine distribution and thermal energies of a few tenths of an eV. The vaporized material arrives at a substrate surface having a mass per unit area dm dA) given by... 

Fig. 6. Cosine distribution of vaporized material from a point source (a) distribution of deposited material from a point source, and (b) distribution of film...

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