No abstract

The thermal stability in structural and electrical properties of HfO 2 , HfAlO x alloy, and Al 2 O 3 /HfO 2 stack thin films prepared by atomic layer deposition were comparatively investigated. Both HfAlO x and Al 2 O 3 /HfO 2 exhibit improved property against thermal degradation compared to the HfO 2 film. However, the incorporation of Al in alloy form provides characteristics superior to that in stack structure by retaining an amorphous structure up to 1000°C, which suppresses the leakage current and retards the growth of interfacial layer giving rise to lower increment of equivalent-oxide-thickness and interface trap density.

The polymerization experiments were carried out in a calorimeter modified for UV irradiation [22]. The samples were prepared by adding 1 wt.-% photoinitiator, Irgacure 651 (Ciba-Geigy), and 200 ppm of inhibitor p-methoxyphenol to the monomer to avoid thermal polymerization (81.To prepare the polymer films, the monomers, provided with initiator and inhibitor, are pressed at 120-125°C between glass plates coated with polyimide. They are left at this temperature until a defect-free homeotropic alignment, with disks parallel to the substrate, is obtained (black films between crossed polarizers in optical microscopy). The films, from 4 to 15 pm thick, are then exposed to UV radiation for 15 min at varied polymerization temperatures. The resulting materials are defect-free, transparent and colorless.The ordinary (no) and extraordinary (n,) refractive indices of 2 and poIy(2) are measured with an Abbe refractometer. Wide-angle X-ray diffraction experiments were carried out on a Siemens Hi-Star Area Detector, using CuKa radiation.

SARS-CoV-2 infects humans through the binding of viral S-protein (spike protein) to human ACE2 (angiotensin I converting enzyme 2). The structure of the ACE2-S-protein complex has been deciphered and we focused on the 27 ACE2 residues that bind to S-protein. From human sequence databases, we identified 9 ACE2 variants at ACE2-S-protein binding sites. We used both experimental assays and protein structure analysis to evaluate the effect of each variant on the binding affinity of ACE2 to S-protein. We found one variant causing complete binding disruption, two and three variants, respectively, strongly and mildly reducing the binding affinity, and two variants strongly enhancing the binding affinity. We then collected the ACE2 gene sequences from 57 non-human primates. Among the six apes and 20 Old World monkeys (OWMs) studied we found no new variants. In contrast, all 11 New World monkeys (NWMs) studied share four variants each causing a strong reduction in binding affinity, the Philippine tarsier also possesses three such variants, and 18 of the 19 prosimian species studied share one variant causing a strong reduction in binding affinity. Moreover, one OWM and three prosimian variants increased binding affinity by > 50%. Based on these findings we proposed that the common ancestor of primates was strongly resistant to and that of NWMs was completely resistant to SARS-CoV-2 and so is the Philippine tarsier, whereas apes and OWMs, like most humans, are susceptible. This study increases our understanding of the differences in susceptibility to SARS-CoV-2 infection among primates.

The charge storage characteristics of metal-oxide-semiconductor structures containing Au nanocrystals in atomic-layer-deposited high-k gate dielectrics were studied. Cross-sectional high-resolution transmission electron microscopy reveals that the Au nanocrystals are self-assembled in the high-k dielectric matrix after high temperature annealing in N2 ambient. The memory effect was observed from capacitance-voltage (C-V) relations and a satisfactory charge retention characteristic was obtained in the sample using Al2O3 as the gate dielectric than in the one using Hf2AlOx. Moreover, a saturation of electron storage in the metal-oxide-semiconductor capacitors was also observed.