Anisotropic Dielectric Breakdown Strength of Single Crystal Hexagonal Boron Nitride

Dielectric breakdown has historically been of great interest from the perspectives of fundamental physics and electrical reliability. However, to date, the anisotropy in the dielectric breakdown has not been discussed. Here, we report an anisotropic dielectric breakdown strength (EBD) for h-BN, which is used as an ideal substrate for two-dimensional (2D) material devices. Under a well-controlled relative humidity, EBD values in the directions both normal and parallel to the c axis (EBD+c & EBD//c) were measured to be 3 and 12 MV/cm, respectively. When the crystal structure is changed from sp3 of cubic-BN (c-BN) to sp2 of h-BN, EBD+c for h-BN becomes smaller than that for c-BN, while EBD//c for h-BN drastically increases. Therefore, h-BN can possess a relatively high EBD concentrated only in the direction parallel to the c axis by conceding a weak bonding direction in the highly anisotropic crystal structure. This explains why the EBD//c for h-BN is higher than that for diamond. Moreover, the presented EBD value obtained from the high quality bulk h-BN crystal can be regarded as the standard for qualifying the crystallinity of h-BN layers grown via chemical vapor deposition for future electronic applications

Point Cloud Denoising and Outlier Detection with Local Geometric Structure by Dynamic Graph CNN

The digitalization of society is rapidly developing toward the realization of the digital twin and metaverse. In particular, point clouds are attracting attention as a media format for 3D space. Point cloud data is contaminated with noise and outliers due to measurement errors. Therefore, denoising and outlier detection are necessary for point cloud processing. Among them, PointCleanNet is an effective method for point cloud denoising and outlier detection. However, it does not consider the local geometric structure of the patch. We solve this problem by applying two types of graph convolutional layer designed based on the Dynamic Graph CNN. Experimental results show that the proposed methods outperform the conventional method in AUPR, which indicates outlier detection accuracy, and Chamfer Distance, which indicates denoising accuracy.Comment: 2023 IEEE 12th Global Conference on Consumer Electronics (GCCE 2023

Prospective and retrospective values integrated in frontal cortex drive predictive choice

予測に基づいて行動を選ぶ脳の回路の発見 --2次運動野が担う予測的な行動選択--. 京都大学プレスリリース. 2023-01-30.Animals must flexibly estimate the value of their actions (action-value) to successfully adapt to a changing environment. The brain is thought to estimate action-values from two different sources, namely the action-outcome history (retrospective value) and the knowledge of the environment (prospective value), but how different estimates of action-values are reconciled to make a choice is not well understood. Here we found that as mice learn the state-transition structure of a decision-making task, retrospective and prospective values become jointly encoded in the preparatory activity of neurons in ALM. Suppressing this preparatory activity in expert mice returned their behavior to a naïve state. These results reveal the neural circuit that injects structural knowledge into action selection to promote predictive decision-making

Compositional Features of Japanese Humic Substances Society Standard Soil Humic and Fulvic Acids by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and X-Ray Diffraction Profile Analysis

The composition of humic acids (HAs) and Fulvic Acids (FAs) from Inogashira (Umbric Andosol) and Dando (Dystric Cambisol) soils authorized as standard samples by the Japanese Humic Substances Society was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and X-ray diffraction (XRD) 11 band profile analysis. In FTICR-MS, the number of peaks that molecular formulas were assigned to was 2549-2913 for the FAs and 1943-2457 for the HAs. Molecular formulas with H/C and O/C ratios similar to condensed hydrocarbons were dominant in both the HAs, while those with H/C and O/C ratios similar to lignin were more abundant in the Dando HAs than in the Inogashira HAs. In both the FAs, molecular formulas having H/C and O/C ratios similar to lignin, condensed hydrocarbons, and tannins were dominant. The double bond equivalent (DBE), an index of the degree of unsaturation, was in the range of 0-30. However, larger DBE values of 26-30 were observed only in the Inogashira HAs with a larger degree of humification. The XRD results also showed that the Inogashira HAs contain larger amounts of condensed aromatic structures with a higher condensation degree. Relative content of carbon layer planes estimated from the peak area of the 11 band profile analysis, which could be estimated only for HAs, was 0.48-1.68 nm (4-37 rings) in the Inogashira HAs and 0.48-1.20 nm (4-19 rings) in the Dando HAs

2-(2,7-Dimeth­oxy-1-naphtho­yl)benzoic acid

In the title compound, C20H16O5, the dihedral angle between the naphthalene ring system and the benzene ring is 67.43 (5)°. The bridging carbonyl C—C(=O)—C plane makes dihedral angles of 82.64 (6) and 41.79 (7)°, respectively, with the naphthalene ring system and the benzene ring. The dihedral angle between the carb­oxy O—C(=O)—C plane and the benzene ring is 36.38 (7)° and that between the bridging carbonyl C—C(=O)—C plane and the carb­oxy O—C(=O)—C plane is 51.88 (8)°. The crystal structure is stabilized by inter­molecular O—H⋯O and C—H⋯O hydrogen-bonding inter­actions. An intra­molecular C—H⋯O hydrogen bond occurs between a naphthalene H atom and the carbonyl O atom of the carb­oxy group

2,7-Dimethoxy­-1-(4-nitro­benzo­yl)-naphthalene

In the title compound, C19H15NO5, the dihedral angle between the naphthalene ring system and the benzene ring is 61.97 (5)°. The dihedral between the naphthalene ring system and the bridging carbonyl C—C(=O)—C plane is 54.68 (6)°, far larger than that [12.54 (7)°] between the phenyl group and the bridging carbonyl group. The nitro group and the phenyl ring are almost coplanar [O—N—C—C torsion angle = 2.94 (19)°]. In the crystal, mol­ecules are linked by C—H⋯π inter­actions and the phenyl rings are involved in a centrosymmetric π–π inter­action with a perpendicular distance of 3.523 Å and a lateral offset of 1.497 Å. In addition, weak inter­molecular C—H⋯O hydrogen bonds are formed between an H atom of one meth­oxy group and a nearby carbonyl O atom