Turbulence resulting from Kelvin–Helmholtz instability in layers of localized stratification and shear is studied by means of direct numerical simulation. Our objective is to present a comprehensive description of the turbulence evolution in terms of simple, conceptual pictures of shear–buoyancy interaction that have been developed previously based on assumptions of...
Models for surface gravity wave propagation in the presence of currents often assume the current field to be quasi-stationary, which implies that the absolute wave frequency is time invariant. However, in the presence of unsteady currents or time-varying water depth, linear wave theory predicts a time variation of the absolute...
This article was originally published online and in print with an incorrect version of Fig. 1. AIP apologizes for this error. All online versions of the article have been corrected.
We demonstrate a surface enhanced Raman scattering (SERS) substrate by integrating plasmonic-active SiO₂ nanotubes into Si₃N₄ gratings. First, the dielectric grating that is working under guided mode resonance (GMR) provides enhanced electric field for localized surface plasmon polaritons on the surface of metallic nanoparticles. Second, we use SiO₂ nanotubes with...
Low temperature atomic layer deposition (ALD) of monolayer to few layer MoS₂ uniformly across 150mm diameter SiO₂/Si and quartz substrates is demonstrated. Purge separated cycles of MoCl5 and H₂S precursors are used at reactor temperatures of up to 475 °C. Raman scattering studies show clearly the in-plane (E¹₂g) and out-of-plane...
We compare characteristics of electron impact ionization (EI) and multiphoton ionization (MPI) of doped super fluid helium droplets using the same droplet source. Selected dopant ion fragments from the two ionization schemes demonstrate different dependence on the doping pressure, which could be attributed to the different ionization mechanisms. While EI...
The kinetics of laser-induced, liquid-mediated crystallization of amorphousGe thin films were studied using multi-frame dynamic transmission electron microscopy (DTEM), a nanosecond-scale photo-emission transmission electron microscopy technique. In these experiments, high temperature gradients are established in thin amorphousGe films with a 12-ns laser pulse with a Gaussian spatial profile. The hottest...
The authors present a facile, low-cost methodology to fabricate high-performance In-Ga-Zn-O (IGZO) bottom contact, bottom gate thin-film transistors (TFTs) by soft lithography. The IGZO channel and indium tin oxide (ITO) source and drain were patterned using microcontact printing of an octadecylphosphonic acid self-assembled monolayer (SAM). A polymer stamp was used...
We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He₂ ⁺ and He₄ ⁺, which...
We report a facile method of doping cations from an electrospray ionization (ESI) source into superfluid helium droplets. By decelerating and stopping the ion pulse of reserpine and substance P from an ESI source in the path of the droplet beam, about 10⁴ ion-doped droplets (one ion per droplet) can...