Non uniform shrinkages of double-walled carbon nanotube as induced by electron beam irradiation

Electron beam-induced nanoinstabilities of pristine double-walled carbon nanotubes (DWCNTs) of two different configurations, one fixed at both ends and another fixed at only one end, were in-situ investigated in transmission electron microscope at room temperature. It was observed that the DWCNT fixed at both ends shrank in its diameter uniformly. Meanwhile, the DWCNT fixed at only one end intriguingly shrank preferentially from its free cap end along its axial direction whereas its diameter shrinkage was offset. A mechanism of "diffusion" along with "evaporation" at room temperature which is driven by the nanocurvature of the DWCNTs, and the athermal activation induced by the electron beam was proposed to elucidate the observed phenomena. The effect of the interlayer interaction of the DWCNTs was also discussed

Synthesis, properties, and optical applications of noble metal nanoparticle-biomolecule conjugates

Noble metal nanoparticles, such as gold or silver nanoparticles and nanorods, exhibit unique photonic, electronic and catalytic properties. Functionalization of noble metal nanoparticles with biomolecules (e. g., protein and DNA) produces systems that possess numerous applications in catalysis, delivery, therapy, imaging, sensing, constructing nanostructures and controlling the structure of biomolecules. In this paper, the recent development of noble metal nanoparticle-biomolecule conjugates is reviewed from the following three aspects: (1) synthesis of noble metal nanoparticle-biomolecule systems by electrostatic adsorption, direct chemisorption of thiol derivatives, covalent binding through bifunctional linkers and specific affinity interactions; (2) the photonic properties and bioactivation of noble metal nanoparticle-biomolecule conjugates; and (3) the optical applications of such systems in biosensors, and medical imaging, diagnosis, and therapy. The conjugation of Au and Ag nanoparticles with biomolecules and the most recent optical applications of the resulting systems have been focused on

Kinetics of solid phase epitaxy of amorphous Si induced by self-ion implantation into Si with nanocavities

The solid phase epitaxial regrowth of structurally modified amorphous silicon created by self-ion implantation into nanovoided crystalline silicon is investigated. It is demonstrated that although the modified amorphous silicon is fully reconstructed into single crystal during the epitaxial regrowth, both activation energy and atom attempt frequency for the regrowth are much higher than those of the typical amorphous Si induced by self-ion implantation into Si wafer without nanovoids. The novel regrowth kinetics indicates that the modified amorphous silicon would contain a very high concentration of dangling bonds, which are believed to result from dissociation of the nanovoids originally metastablized in crystalline silicon. The unparalleled sensitivity of SPEG provides an effective and simple way to detect and characterize the subtle structural changes at nanometer scale in amorphous Si

Effect of the blade outlet angle on unsteady characteristics of a single channel pump

To study the effect of β2 on energy performance and unsteady characteristics of the single-channel pump, the experimental tests about the energy characteristics, head pulsation, pressure fluctuation and radial force have been conducted by the synchronous test. 3 different impellers with the blade outlet angle β2 of 8°, 16° and 25° respectively are studied. The results show that with the increase of β2 from 8° to 25°, the head increases gradually and the maximum increase amplitude reaches 22.6 %. As β2 changes from 8° to 25°, there is a maximum efficiency. The mixing loss at the impeller outlet can be decreased by reducing β2. With the increasing of β2, the minimum head in time domain gradually lag and the maximum head gradually advances. The pressure fluctuation in each measuring point shows the trend of increasing first and then decreasing with the increasing of the flow rate. With β2 increasing, the radial force also increases and the maximum increase amplitude of minimum radial force is larger than 8 %. The research can provide some reference for the optimization of single channel pumps