Surface irradiation

Figure Bl.25.6. Energy spectrum of electrons coming off a surface irradiated with a primary electron beam. Electrons have lost energy to vibrations and electronic transitions (loss electrons), to collective excitations of the electron sea (plasmons) and to all kinds of inelastic process (secondary electrons). The element-specific Auger electrons appear as small peaks on an intense background and are more visible in a derivative spectrum.

One other technique has become central in surface research this is X-ray photoelectron spectrometry, earlier known as ESCA, electron spectroscopy for chemical analysis . Photoelectrons are emitted from a surface irradiated by X-rays. The precautions which have to be taken to ensure accurate quantitative analysis by this much-used technique are set out by Seah (1980). 

Figure 5.19 Formation of amino acids on ice surfaces irradiated in the laboratory (Nature Nature 416, 403-406 (28 March 2002) doi 10.1038/416403a-permission granted). Data were obtained from analysis of the room temperature residue of photoprocessed interstellar medium ice analogue taken after 6 M HCl hydrolysis and derivatization (ECEE derivatives, Varian-Chrompack Chirasil-L-Val capillary column 12 m x 0.25 mm inner diameter, layer thickness 0.12 pirn splitless injection, 1.5 ml min-1 constant flow of He carrier gas oven temperature programmed for 3 min at 70°C, 5°C min-1, and 17.5 min at 180°C detection of total ion current with GC-MSD system Agilent 6890/5973). The inset shows the determination of alanine enantiomers in the above sample (Chirasil-L-Val 25 m, single ion monitoring for Ala-ECEE base peak at 116 a.m.u.). DAP, diaminopentanoic acid DAH, diaminohexanoic acid a.m.u., atomic mass units.

CASRN 51707-55-2 molecular formula C9H8N4OS FW 220.20 Soil. The reported half-life in soil is approximately 26-144 d (Hartley and Kidd, 1987). Photolytic. Klehr et al. (1983) studied the photolysis of thiadiazuron on adsorbed soil surfaces. Irradiation was conducted using artificial sunlight having a wavelength <290 nm. The amount of thiadiazuron remaining after irradiation times of 0.25, 0.5, 1, 2, 3.75, and 18.0 h were 56.4, 42.8, 35.7, 23.8, 25.0, and 67.2%, respectively. The primary photoproduct identified was l-phenyl-3-(l,2,5-thiadiazol-3-yl)urea and five unknown polar compounds. The unknown com pounds could not be identified because the quantities were too small to be detected. 

Murcray, F. J A. Goldman, J. C. Landry, and T. M. Stephen, 02 Continuum A Possible Explanation for the Discrepancies between Measured and Modeled Shortwave Surface Irradiances, Geophys. Res. Lett., 24, 2315-2317 (1997). 

Justus C.G. and B.B. Murphey, Temporal trends in surface irradiance at ultraviolet wavelengths, J. Geophys. Res., 99,1389-1394, 1994... 

High light intensity may have decreased the concentration of secondary metabolites if the plants were stressed by the high irradiance (see the environmental stress theory, Section IV.D). The plants grown at 100% of surface irradiance probably received high doses of ultraviolet radiation as well as photosynthetically active radiation. Ultraviolet radiation can stress Dictyota ciliolata, leading to decreased concentrations of secondary metabolites.183... 

Figure 23.10 Representation of photocontrolled ion-binding at an SP-modified surface, (a) Colorless SP-immobilized surface, (b) On illumination with UV light, the surface becomes active and bright purple due to the photoisomerizalion of SPto MC. On illumination of this surface with visible light MC is switched back to SP. (c) Exposure of activated surface to an aqueous solution of divalent metal ions leads to formation of the complex MC-M+ and further color change of the surface. Irradiation of this surface with green light leads to transformation of MC-M+ to SP. The cycle is closed and the surface is returned to the passive, colorless state.

Dr. Honle AG UV-Technologie (Planegg/Miinchen, Germany), P. Wind information and a photograph concerning the surface irradiation system used for bottle screw cap disinfection. 

The radiation balance of a layer with the thickness d having an infinitely large surface, irradiated homogeneously from one side with exciting radiation, is given by the solution of four coupled linear first-order differential equations (Eqs. 3.5-1...4). This is a boundary value problem, with the definitions given in Fig. 3.5-2. We are discussing... 

Figure 1. Infrared spectrum of surface irradiated carbonate protected polyvinyl phenol/onium salt resist.

Figure 2. Infrared spectra of surface irradiated resist A and the dye modified masked resist B.

Figure 3. UV spectra of the carbonate protected phenolic, after surface irradiation with 500 fjJ/220 nm light, and after reaction with phenyl isocyanate. Note the extreme absorptivity at the flood exposure wavelength of 254 nm.

Beef is aged at 4°C and is tenderized. A process involving surface irradiation controls microbial growth and permits somewhat higher temperatures to accelerate tenderization. 

Figure 11.7 Time course of nutrients and chlorophyll a in the nutrient-addition hioassay performed on a Chesapeake Bay ahove-pycnocline water sample from stationTF1.5 (Patuxent Tidal Fresh Region) in September 2000. Nutrients were added as one dose just after the initiation of the hioassay (0 days). N was added as NFI4 (NFI4CI) and P was added as P04 (NaH2P04). Added NH4 was rapidly depleted, whereas excess P was present in all treatments except +N. The hioassay was incubated at 60% of surface irradiance. Chlorophyll a responded strongly to any N addition, but not in the control nor to P additions (adapted from Fisher and Gustafson, 2004).

Figure 12.2 SOFeX depth profiles of biomass (PN)-specific NO/ uptake rates, determined during 24-h incubations in Plexiglas acrylic incubators under simulated in-situ light and temperature conditions. Ultra-clean trace-metal techniques were used for sample collection within and outside (control waters) of the Fe-enriched patch north and south of the Antarctic Polar Front zone. The/-values [f = Fn03/(1 n03 + 1 nH4 + F n02 + F Urea)] were determined at the isolume depths of 47 and 16% surface irradiance, using tracer-level isotopic enrichments, and are not corrected for the effects of isotopic dilution. Error bars represent the range of duplicate samples (n = 2). Corrected from Coale et al. (2004).

In the Indian sector, Slawyk (1979) demonstrated that both NH and NO uptake could be described by a hyperboHc relationship, NH uptake required less light than NO to support the maximal uptake rates reahzed (the Klx for NH was less than the Klt for NOJ), and irradiances in excess of 25% of the surface irradiance did not enhance specific rates of NH and NO uptake. During a series of NO uptake versus irradiance experiments conducted in the Ross Sea during austral spring and summer, Hu and Smith (1998) also showed that relatively low irradiances... 

N, 155°W Mar-Apr integrated to 1% surface irradiance Total photo-autotrophic N assimilation Uptake of " C-HCOs 58.7-84.9 Laws et al. (1989)... 

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