نتایج جستجو برای: vls mechanism
تعداد نتایج: 565830 فیلتر نتایج به سال:
We present the design of an ultrafast monochromator explicitly designed for extreme-ultraviolet FEL sources, in particular the upcoming FLASH II at DESY. The design originates from the variable-line-spaced (VLS) grating monochromator by adding a second grating to compensate for the pulse-front tilt given by the first grating after the diffraction. The covered spectral range is 6-60 nm, the spec...
Four kinds of nanostructures, nanoneedles, nanohooks, nanorods, and nanotowers of In2O3, have been grown by the vapor transport process with Au catalysts or without any catalysts. The morphology and structure of the prepared nanostructures are determined on the basis of field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM). The ...
Selective growth of boron nitride nanotubes (BNNTs) was demonstrated by plasma-enhanced pulsed laser deposition (PE-PLD). Although PLD is a physical vapor deposition technique for the growth of boron nitride (BN) thin films, ion sputtering induced by the plasma can eliminate the formation of BN thin films and lead to the so-called total resputtering region, in which, a pure phase of BNNTs can b...
Peculiar and unique growth mechanisms involved in semiconductor nanowires (NWs) pave the way to achievement of new crystallographic phases remarkable material properties, hence, studying polytypism NWs arouses a strong interest for next generation electronic photonic applications. In this context, ZnS has been investigated, as bulk compound exhibits numerous unstable polytypes at high temperatu...
Polymer-derived ultra-high-temperature ceramic (UHTC) nanocomposites have attracted growing attention due to the increasing demands for advanced thermal structure components in aerospace. Herein, hafnium carbide (HfC) whiskers are successfully fabricated carbon fiber preforms via polymer-derived (PDC) method. A novel nanotube (CNT) template growth mechanism combined with PDC method is proposed ...
The radicals and atoms generated by a plasma have the effect, among others, of changing surface energies materials, which allows one to prepare nano-objects that would not stabilise in other conditions. This is case Sn catalysed silicon nanowires (NWs) we present this paper: without plasma, liquid at top NWs unstable (because naturally wets Si) so no growth allowed, while presence H balance dra...
ii ABSTRACT Surface energetics play an important role in processes on the nanoscale. Nanowire growth via vapor-liquid-solid (VLS) mechanism is no exception in this regard. Interfacial and line energies are found to impose some fundamental limits during three-phase nanowire growth and lead to formation of stranded nanowires with fascinating characteristics such as high responsiveness towards ion...
Elevated intracellular levels of cyclic guanosine monophosphate (cGMP) may induce apoptosis, and at least some cancer cells seem to escape this effect by increased efflux of cGMP, as clinical studies have shown that extracellular cGMP levels are elevated in various types of cancer. The human ATP binding cassette (ABC) transporter ABCC5 transports cGMP out of cells, and inhibition of ABCC5 may h...
The morphological phase diagram is reported for InP nanostructures grown on InP (111)B as a function of temperature and V/III ratio. Indium droplets were used as the catalyst and were generated in situ in the metalorganic vapor-phase epitaxy reactor. Three distinct nanostructures were observed: wires, cones, and pillars. It is proposed that the shape depends on the relative rates of indium phos...
The potency of 2 nucleoside reverse transcriptase inhibitors (NRTIs) and efavirenz in patients with higher viral loads (VLs) or low CD4 cell counts remains uncertain. Virologic failure and changes in CD4 count in relation to pretreatment VL and CD4 count were evaluated in treatment-naive patients randomized to treatment groups that received 2 or 3 NRTIs with efavirenz. Over 3 years, the risk of...
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