Silicon nanocrystals were in situ grown in a silicon nitride film by plasma-enhanced chemical vapor deposition. The size and structure of silicon nanocrystals were confirmed by high-resolution transmission electron microscopy. Depending on the size, the photoluminescence of silicon nanocrystals can be tuned from the near infrared (1.38eV) to the ultraviolet (3.02eV). The fitted photoluminescence peak energy as E(eV)=1.16+11.8∕d2 is evidence for the quantum confinement effect in silicon nanocrystals. The results demonstrate that the band gap of silicon nanocrystals embedded in silicon nitride matrix was more effectively controlled for a wide range of luminescent wavelengths.

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X-ray diffraction data were collected from human rhinovirus 14 crystals a few minutes after exposure to acid vapor and prior to excessive crystalline disorder. Conformational changes occurred (i) in the GH loop of viral protein (VP) 1, (it) at the ion binding site on the outer surface of the pentamer center, and (us) in VP3 and VP4 on the virion's interior in the vicinity of the fivefold axis. Amino acid substitutions in mutants resistant to low pH, or to drugs that inhibit uncoating, were concentrated in the vicinity of the GH loop. It is proposed that the acid-induced changes reflect processes that trigger uncoating.