Segmentation of Planar Surfaces from Laser Scanning Data Using the Magnitude of Normal Position Vector for Adaptive Neighborhoods

Diverse approaches to laser point segmentation have been proposed since the emergence of the laser scanning system. Most of these segmentation techniques, however, suffer from limitations such as sensitivity to the choice of seed points, lack of consideration of the spatial relationships among points, and inefficient performance. In an effort to overcome these drawbacks, this paper proposes a segmentation methodology that: (1) reduces the dimensions of the attribute space; (2) considers the attribute similarity and the proximity of the laser point simultaneously; and (3) works well with both airborne and terrestrial laser scanning data. A neighborhood definition based on the shape of the surface increases the homogeneity of the laser point attributes. The magnitude of the normal position vector is used as an attribute for reducing the dimension of the accumulator array. The experimental results demonstrate, through both qualitative and quantitative evaluations, the outcomes’ high level of reliability. The proposed segmentation algorithm provided 96.89% overall correctness, 95.84% completeness, a 0.25 m overall mean value of centroid difference, and less than 1° of angle difference. The performance of the proposed approach was also verified with a large dataset and compared with other approaches. Additionally, the evaluation of the sensitivity of the thresholds was carried out. In summary, this paper proposes a robust and efficient segmentation methodology for abstraction of an enormous number of laser points into plane information

Mechanical Fatigue Resistance of Piezoelectric PVDF Polymers

The fatigue resistance of piezoelectric PVDF has been under question in recent years. While some report that a significant degradation occurs after 106 cycles of repeated voltage input, others report that the reported degradation originates from the degraded metal electrodes instead of the piezoelectric PVDF itself. Here, we report the piezoelectric response and remnant polarization of PVDF during 107 cycles of repeated compression and tension, with silver paste-based electrodes to eliminate any electrode effect. After applying repeated tension and compression of 1.8% for 107 times, we do not observe any notable decrease in the output voltage generated by PVDF layers. The results from tension experiments show stable remnant polarization of 5.5 μC/cm2, however, the remnant polarization measured after repeated compression exhibits a 7% decrease as opposed to the tensed PVDF. These results suggest a possible anisotropic response to stress direction. The phase analyses by Raman spectroscopy reveals no significant change in the phase content, demonstrating the fatigue resistance of PVDF

Growth Enhancement and Nitrogen Loss in ZnO_<i>x</i>N_<i>y</i> Low-Temperature Atomic Layer Deposition with NH₃

The growth behavior and properties of ZnO_<i>x</i>N_<i>y</i> (ZnON) films grown by atomic layer deposition (ALD) with diethylzinc (DEZ), H₂O, and NH₃ were investigated. Although no growth of a ZnN_<i>x</i> film occurs at 150 °C from DEZ and NH₃, the ZnON film thickness is increasingly saturated by increasing ZnN_<i>x</i> subcycles in a supercycle up to three successive ZnN_<i>x</i> subcycles. The adsorbed NH₃ during the injection step of NH₃ induces the chemisorption of DEZ on the surface, consequently resulting in the growth enhancement. The optical band gap of the films decreases from 3.25 to 3.0 eV with increasing ZnN<i>_x</i> subcycles. The resistivity of the films is tuned in the range from 4 × 10^–2 to 1 × 10² Ω·cm by the variation of the ZnN_<i>x</i> subcycles. However, the nitrogen concentration in the films is limited to approximately 2 at. % even at very high ZnN_<i>x</i> cycles. The low nitrogen concentration is attributed to the exchange reaction of NH₃ on the ZnON surface with H₂O injected during the following step. These intriguing phenomena are not observed in the ALD of Al₂O_<i>x</i>N_<i>y</i> with trimethylaluminum, which has a similar ligand structure as DEZ, H₂O, and NH₃. This finding demonstrates that the catalytic effect of NH₃ adsorbed on the ZnO surface is critical for the growth enhancement in the ALD of ZnON

Synthesis of SnS Thin Films by Atomic Layer Deposition at Low Temperatures

Two-dimensional (2-D) metal chalcogenides have received great attention because of their unique properties, which are different from bulk materials. A challenge in implementing 2-D metal chalcogenides in emerging devices is to prepare a well-crystallized layer over large areas at temperatures compatible with current fabrication processes. Tin monosulfide, a <i>p</i>-type layered semiconductor with a high hole mobility, is a promising candidate for realizing large-area growth at low temperatures because of its low melting point. However, tin sulfides exist in two notable crystalline phases, SnS and SnS₂. Therefore, it is imperative to control the oxidation state of Sn to achieve a pure SnS film. Here, the synthesis of SnS thin films by atomic-layer-deposition (ALD) is demonstrated using bis­(1-dimethylamino-2-methyl-2-propoxy)­tin­(II) and H₂S as Sn and S sources, respectively, over a wide temperature window (90–240 °C). Impurities such as carbon, oxygen, and nitrogen were negligibly detected. The morphological evolution of plate-like orthorhombic SnS grains was observed above 210 °C. Moreover, properties of thin film transistors and gas sensors using SnS films as the active layers were investigated. The SnS ALD process would provide promising opportunities to exploit the intriguing properties of the 2-D metal chalcogenides for realizing emerging electronic devices

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

non present