The effect of preadsorbed Sm atoms on CO adsorption
has been studied over the Ru(001) surface, employing
temperature-programmed desorption and photoemission spectroscopy.
It was found that the presence of Sm
atoms yields more tightly bound CO species compared with CO molecules
adsorbed on clean Ru sites. The
tightly bound CO species interact attractively with coadsorbed Sm
atoms, and this attractive interaction leads
to a formation of two-dimensional Sm + CO coadsorption islands on the
surface. It seems that the Sm +
CO coadsorption island gives additional adsorption sites, which
interact very weakly with CO located upon
the island. Upon heating the Sm + CO coadsorbed layer, the
tightly bound CO located inside the Sm + CO
island subsequently dissociated and oxidized Sm to form two-dimensional
compounds.
Nitrogen was chemisorbed on an alumina ( Al2O3) surface by plasma discharge of N2, and the chemical behavior of chemisorbed nitrogen was studied by temperature-programmed desorption (TPD) and infrared (IR) spectroscopy. Molecular nitrogen N2(ad) chemisorbed on an Al2O3 surface showed a high reactivity with hydrogen even at room temperature, if Pt is present on the Al2O3 surface. Hydrogenated species, NH
x
(ad) (x=1 or 2) and NH3(ad), were formed on the Al2O3 surface, as evidenced by IR spectroscopy. It is suggested that hydrogen spill-over from the Pt surface onto the Al2O3 catalyst plays an important role in the mechanism of hydrogenation reaction.
Heat generation caused by high-amplitude ultrasonic vibrations at the interface has long been believed to be the most dominant factor for the mechanism of ultrasonic plastic joining. However, the authors have not found any conspicuous thermal effects in experiments of ultrasonic joining of thin very low density polyethylene (VLDPE) films using torsional vibrations. In the process of joining, the temperature at the interface of two VLDPE films of 0.1 mm thickness has increased up to 73 C only and no trace of melting of the material has been observed at this interface under a polarizing microscope. Investigation using a differential scanning calorimeter (DSC) has revealed that the ''melting point'' of VLDPE is about 110 C, and an ultrasonically joined specimen, unlike a heat-sealed specimen, shows no significant difference in thermal characteristics compared with an intact VLDPE film. The VLDPE films cannot be been joined, even after being pressed together for a period of 30 min or longer at a temperature approximately 80 C.
, carried out from 2010 to 2012, polyethylene reference sample (PE-RS) pieces and six types of polypropylene (PP) were subjected to accelerated weathering tests and outdoor exposure tests, resulting in the following findings. (1) The PE-RS was subjected to eight 100 h exposure tests in the same test machine. The accelerated weathering test machines of the participating institutes had high reproducibility. (2) The PE-RS CI values were greater when the temperature in the chamber was greater during accelerated weathering tests, and there was a high correlation with the average temperature in the outdoor exposure tests at 20 places in Japan. (3) By comparing the change in PP strength by normalizing the degradation environment using the PE-RS CI values, the accelerated weathering test with results showing the highest correlation with the outdoor exposure test results was the one with the xenon arc lamp at an irradiance of 60 W/m 2 and a BPT of 63 ∘ C.
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