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991.
Even if it were true that SAR (synthetic aperture radar) ocean surface imagery provides a perfect noiseless representation of ocean surface wave height, each spectrum computed from such imagery would be but a single realization of the ensemble-mean ocean spectrum. There would be sampling variability associated with the parameters of dominant wave number and propagation direction extracted from such a spectrum. The present study addresses two questions: (i) what statistical distribution is applicable to the spectra of SAR ocean images? and (ii) what are the consequences of such statistics on the precision with which wave number and propagation direction can be extracted? An examination is made of spectra computed from ocean imagery acquired during the SIR-B (Shuttle Imaging Radar-B) mission  相似文献   
992.
A method has been developed for the analysis of cimaterol and clenbuterol residues in liver, with detection limits of 0.25 micrograms/kg and 0.5 micrograms/kg, respectively. The recovery varied from 55% to 60%. After extraction, a clean-up procedure with Baker-spe C-18 columns was performed. The two chemical compounds of interest were eluted with methanol. Cimaterol and clenbuterol were quantitatively determined by high-performance liquid chromatography (HPLC) using an RP-Select B (5 microns) column and a post-column reaction procedure. The positive results were confirmed by high-performance thin-layer chromatography (HPTLC) as this technique reaches the same level of sensitivity as the HPLC method.  相似文献   
993.
The catalyst behaviour of titanium silicalite, which was found the most active and selective catalyst for liquid-phase ammoximation of cyclohexanone to the corresponding oxime with hydrogen peroxide, was investigated in the gas-phase ammoximation with molecular oxygen in and compared with those of pure silicalite and samples of vanadium and chromium silicalites. The results showed that Ti-silicalite is a selective catalyst not only in the reaction with hydrogen peroxide but also in the reaction with molecular oxygen. However, a big limitation was found in the poor activity of the silicalites which do not allow to reach high oxime yields.  相似文献   
994.
The number of circuit design iterations due to electrostatic discharge (ESD) failures increases with the complexity of VLSI technologies and their shrinking. In this paper, we show how TCAD and ESD SPICE modeling can be used to solve ESD protection issues in an analog CMOS technology.  相似文献   
995.
Performance on computer-simulated, everyday memory tasks was found to deteriorate with age in 434 Belgian (aged 14–88 yrs) and 434 American Ss matched on gender and age. This age-related memory decline was reasonably consistent across samples. Difficulties in cross-cultural research and the advantages of ecologically valid measurement instruments are discussed. Instruments included a grocery list selective reminding test, the Wechsler Memory Scale, the Benton Visual Retention Test, and the Wechsler Adult Intelligence Scale (WAIS). (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
996.
Acrosomal integrity of bovine spermatozoa was evaluated using naphthol yellow S-erythrosine B stain with bright-field microscopy, .2% glutaraldehyde fixation with Nomarski optics, and live wet smears with Nomarski optics to compare the evaluation techniques. Four ejaculates per two Holstein bulls were enriched through a Percoll gradient, capacitated with heparin, and acrosome-reacted with lysophosphatidylcholine to prepare spermatozoa for in vitro fertilization. Spermatozoa samples were taken after each preparatory step, and percentage of intact acrosomes was evaluated with the stain, .2% glutaraldehyde, and live wet smear. Acrosomal integrity decreased with each preparatory step across all techniques. The decrease in integrity from heparin to lysophosphatidylcholine indicated that all methods detected the acrosome reaction. Technique means across preparation steps showed no differences. Correlations between microscopy techniques were high. The live wet smear used no fixation methods. Both the naphthol yellow S-erythrosine B stain and the .2% glutaraldehyde techniques employed fixation steps that may have introduced artifacts that could influence the data. The live wet smear evaluated by Nomarski optics allowed a comparable evaluation of the acrosome-reacted bovine spermatozoa. Comparing brightfield with differential interference contrast microscopy for detecting the acrosome reaction in bovine spermatozoa showed that both methods were equally accurate.  相似文献   
997.
A novel wiggler design for use in free-electron lasers (FELs) is proposed, consisting of a staggered array of magnetic poles situated inside the bore of a solenoid. The resultant field pattern consists of a periodic transverse magnetic field on axis, as well as a longitudinal guide field. Such a wiggler has several advantages: the longitudinal field acts to confine the electrons near the FEL axis, high fields can be attained at short wiggler periods, the field strength is easily varied, and fabrication and testing of the wiggler are relatively easy. It is planned to use this wiggler design in a far infrared FEL to be built at Stanford University  相似文献   
998.
Oxidative Stability of Frozen Pork Patties. Effect of Light and Added Salt   总被引:3,自引:0,他引:3  
Salt (1%) and light effects on oxidative deterioration were followed during freezer storage (?18°C) in a display cabinet. Oxymyoglobin oxidation and lipid oxidation were strongly accelerated by added salt and more moderately by exposure to fluorescent light. The light-dependent lipid oxidation was prevented by using packaging material with incorporated UV-light absorber. However, a UV-light absorber only yielded partial protection against discoloration. The two oxidation processes showed similarities in progression. In contrast to color deterioration, lipid oxidation showed an initial lag period in agreement with previous indications that pigment oxidation was an initiator of lipid oxidation in beef during freezer storage.  相似文献   
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