The structure transition of nanoparticles has a significant effect on their practical applications. In this study, the transition
temperature of CdS nanoparticles with the size of 3–5 nm from sphalerite to wurtzite structure is significantly reduced to
150 °C under a high pressure of 1 GPa, much lower than that 300–400 °C for CdS nanoparticles and 600 °C for bulk CdS under
room pressure. The lower transition temperature leads to an ultrafine grain size d = 5 nm for the formed wurtzite phase as compared with that d = 33 nm yielded under room pressure with a similar transition volume fraction of ~80%. The underlying physical mechanism
is discussed. 相似文献
A new rotational band has been identified and assigned to 188Au for the first time using the 173Yb(19F,4nγ) reaction at the beam energies of 86 and 90 MeV. This band is proposed to be built on the πh9/2 ⊗ νi13/2 configuration by comparing the band properties with known bands in neighboring nuclei. The prolate-to-oblate shape transition through triaxial shape has been proposed to occur around 188Au for the ηh9/2 ⊗ νi13/2 bands in odd-odd Au isotopes on the basis of total Routhian surface (TRS) calculations.
The growth and morphology of two-dimensional (2-D) gold islands on a single-layer graphene supported on Ru(0001) have been studied by scanning tunneling microscopy (STM). Our findings show that gold exhibits 2-D structures up to a gold dosage of 0.75 equivalent monolayers, and that these 2-D gold islands are thermally stable at room temperature. Parallel polarization modulation infrared reflection absorption spectroscopic (PM-IRAS) and high resolution electron energy loss spectroscopic (HREELS) studies indicate that carbon monoxide (CO) adsorbs on these 2-D gold islands at 85 K, showing a characteristic CO stretching feature at 2095 cm? 1 for a saturation coverage of CO. The red shift of the CO stretching frequency compared to that on charge neutral gold is consistent with electron transfer from graphene to gold, i.e., an electron-rich gold overlayer. Preliminary data obtained by dosing molecular oxygen onto this CO pre-covered surface suggest that the 2-D gold islands catalyze the oxidation of CO. 相似文献
Knockout reaction experiment was carried out by using the 6He beams at 61.2 MeV/u impinging on a CH2 target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism can be distinguished by the relation between the polar angles of the core fragments and the recoiled protons, respectively. It is demonstrated that the core knockout mechanism may result in some strong contamination to the real invariant mass spectrum.