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  1. Free, publicly-accessible full text available May 1, 2023
  2. Glasses are nonequilibrium solids with properties highly dependent on their method of preparation. In vapor-deposited molecular glasses, structural organization could be readily tuned with deposition rate and substrate temperature. Here, we show that the atomic arrangement of strong network-forming GeO 2 glass is modified at medium range (<2 nm) through vapor deposition at elevated temperatures. Raman spectral signatures distinctively show that the population of six-membered GeO 4 rings increases at elevated substrate temperatures. Deposition near the glass transition temperature is more efficient than postgrowth annealing in modifying atomic structure at medium range. The enhanced medium-range organization correlates with reduction of the room temperature internal friction. Identifying the microscopic origin of room temperature internal friction in amorphous oxides is paramount to design the next-generation interference coatings for mirrors of the end test masses of gravitational wave interferometers, in which the room temperature internal friction is a main source of noise limiting their sensitivity.
  3. We present the optical and structural characterization of films ofTa2O5,Sc2O3, andSc2O3dopedTa2O5with a cation ratio around 0.1 grown by reactive sputtering. The addition ofSc2O3as a dopant induces the formation of tantalum suboxide due to the “oxygen getter” property of scandium. The presence of tantalum suboxide greatly affects the optical properties of the coating, resulting in higher absorption loss atλ<#comment/>=1064nm. The refractive index and optical band gap of the mixed film do not correspond to those of a mixture ofTa2O5andSc2O3, given the profound structural modifications induced by the dopant.

  4. Amorphous tantala (Ta2O5) thin films were deposited by reactive ion beam sputtering with simultaneous low energy assistAr+orAr+/O2+bombardment. Under the conditions of the experiment, the as-deposited thin films are amorphous and stoichiometric. The refractive index and optical band gap of thin films remain unchanged by ion bombardment. Around 20% improvement in room temperature mechanical loss and 60% decrease in absorption loss are found in samples bombarded with 100-eVAr+. A detrimental influence from low energyO2+bombardment on absorption loss and mechanical loss is observed. Low energyAr+bombardment removes excess oxygen point defects, whileO2+bombardment introduces defects into the tantala films.

  5. Most approaches to automatic facial action unit (AU) detection consider only spatial information and ignore AU dynamics. For humans, dynamics improves AU perception. Is same true for algorithms? To make use of AU dynamics, recent work in automated AU detection has proposed a sequential spatiotemporal approach: Model spatial information using a 2D CNN and then model temporal information using LSTM (Long-Short-Term Memory). Inspired by the experience of human FACS coders, we hypothesized that combining spatial and temporal information simultaneously would yield more powerful AU detection. To achieve this, we propose FACS3D-Net that simultaneously integrates 3D and 2D CNN. Evaluation was on the Expanded BP4D+ database of 200 participants. FACS3D-Net outperformed both 2D CNN and 2D CNN-LSTM approaches. Visualizations of learnt representations suggest that FACS3D-Net is consistent with the spatiotemporal dynamics attended to by human FACS coders. To the best of our knowledge, this is the first work to apply 3D CNN to the problem of AU detection.