Competitive effect between roughness and mask pattern on charging phenomena during plasma etching

In plasma etching process, the edge roughness and mask pattern usually play a significant role in the deformation of holes under the influence of charging effect. The competitive effect between these two factors has been investigated, focusing on the surface charging in a hexagonal array, with various values of roughness parameters (amplitude (A) and wavelength (W)) and distances between holes (L). A series of classical particle dynamic simulations of surface charging, surface etching and profile evolution were used to investigate the effect of roughness and pattern on charging. This study showed that various roughness and patterns (represented by different values of L) can significantly influence surface distributions of the electric-field (E-field) and the etching rates on the mask surface. The simulations also showed that (1) the shape of the pattern array influences the mask hole profile during etching process, i.e. a hexagonal array pattern tends to deform the profile of a circular mask hole into a hexagonal hole; (2) pattern roughness is aggravated during etching process. These factors were found to be significant only at a small feature pitch and may be ignored at a large feature pitch. Possible mechanisms of these results during etching process are discussed. This work sheds light on the ways to maintain pattern integrity and further improve the quality of the pattern transfer onto the substrate.

Application of Direct Numerical Simulation to Determine the Correlation Describing Friction Losses during the Transverse Flow of Fluid in Hexagonal Array Pin Bundles

This paper presents the results of a numerical simulation to determine the hydraulic resistance for a transverse flow through the bundle of hexagonal rods. The calculations were carried out using the precision CFD code CONV-3D, intended for direct numerical simulation of the flow of an incompressible fluid (DNS-approximation) in the parts of fast reactors cooled by liquid metal. The obtained dependencies of the pressure drop and the coefficient of anisotropy of friction on the Reynolds number can be used in the thermal-hydraulic codes that require modeling of the flow in similar structures and, in particular, in the inter-wrapper space of the reactor core.

Photodegradation Behaviour of Nitrogen-Containing Graphene Derivatives Towards Pollutant Dyes and Real-TimeAssessment on Aquatic Weed

Discharge of dyes in the aquatic system is ubiquitous environmental chaos, and combating this particular anthropogenic issue with graphene-based materials via photodegradation process has been a radiant approach in recent times. In this work, 3-aminophenol produced nanosheets of N-graphene (NG) in the presence of urea in a single step at a relatively low temperature of ~ 120 – 125°C in contrast to nitrogen-containing graphene oxide (NGO) produced in the absence of urea. The V- shape of urea facilitated the formation of a poly-hexagonal array of rings and prevented the attack of oxygen at normal atmospheric conditions. During the comparison of the photodegradation ability of both NG and NGO against MG, MB, and MO, the degradation efficiency was found to be 92 - 99%. Further LC-MS/MS studies proved that NGO was capable of mineralizing the complex structures of the dyes via the demethylation route initially followed by asymmetric cleaving at neutral pH. The in-vitro real-time application of an aquatic weed (Lemna minor) was also compared against the 1:1:1 ratio of MG, MB, MO, and NGO-treated dye water. No substantial growth of Lemna minor was found in the case of using the dye mixture even up to the 20th day, whereas rapid growth of this aquatic weed was observed within 15 days in the case of NGO treated dye mixture.

16-element CPW Series Fed Millimeter-wave Hexagonal Array Antenna for 5G Femtocell Applications

A 16-element coplanar waveguide series fed hexagonal array antenna is proposed at millimeter-wave frequency range. In this paper, the analysis is initiated from a single-element hexagonal patch then extended to 1×2 array, 1×4 array, and 4×4 series fed hexagonal patch array antennas. The idea behind this design is to improve fractional bandwidth stage-wise with improved gain maintaining constant efficiency with all the structures. The 16-element array antenna is fabricated on Rogers RT Duriod 5880™ substrate with ɛ r = 2.2 and 0.508 mm thickness. This array antenna exhibits low return loss at 28 GHz with a reflection coefficient value of −31.02 dB including almost 102% radiation efficiency and attained a maximum gain value of 8.98 dBi. The results are quite comparable with simulated 4×4 array antenna using the HFSS tool. The size of the proposed antenna is quite small which will be best suited for 5 G Femtobase stations to provide indoor communications at millimeter-wave frequencies.

Structural Basis for Capsid Recruitment and Coat Formation during HSV-1 Nuclear Egress

During herpesvirus infection, nascent viral capsids egress the nucleus into the cytoplasm by an unusual mechanism whereby capsids bud at the inner nuclear membrane. This process is mediated by the conserved heterodimeric nuclear egress complex (NEC), anchored to the inner nuclear membrane, that deforms the membrane around the capsid by forming a hexagonal array. However, how the NEC coat interacts with the capsid and how proper curvature of the coat is achieved to enable budding are yet unclear. Here, we show that the binding of a capsid protein, UL25, promotes the formation of a pentagonal rather than hexagonal NEC arrangement. Our results suggest that during nuclear budding interactions between the UL25 bound to the pentagonal capsid vertices and the NEC introduce pentagonal insertions into the hexagonal NEC array to yield an NEC coat of the appropriate size and curvature, leading to the productive budding and egress of UL25-decorated capsids.

Structural basis for capsid recruitment and coat formation during HSV-1 nuclear egress

During herpesvirus infection, egress of nascent viral capsids from the nucleus is mediated by the viral nuclear egress complex (NEC). NEC deforms the inner nuclear membrane (INM) around the capsid by forming a hexagonal array. However, how the NEC coat interacts with the capsid and how curved coats are generated to enable budding is yet unclear. Here, by structure-guided truncations, confocal microscopy, and cryoelectron tomography, we show that binding of the capsid protein UL25 promotes the formation of NEC pentagons rather than hexagons. We hypothesize that during nuclear budding, binding of UL25 situated at the pentagonal capsid vertices to the NEC at the INM promotes formation of NEC pentagons that would anchor the NEC coat to the capsid. Incorporation of NEC pentagons at the points of contact with the vertices would also promote assembly of the curved hexagonal NEC coat around the capsid, leading to productive egress of UL25-decorated capsids.