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Planar hexacoordination (ph) is only rarely reported in the literature. So far, only a few neutral and cationic molecules possessing phE (E = C, Si, B, Al, Ga) in the most stable isomer are predicted theoretically. Present electronic structure calculations report hitherto unknown anionic planar hexcoordinate beryllium and magnesium, phBe/Mg, as the most stable isomer. Global minimum searches show that the lowest energy structure of BeC6M3− (M = Al, Ga) and MgC6M3− (M = Ga, In, Tl) is the D3h symmetric phBe/Mg clusters, where beryllium/magnesium is covalently bonded with six carbon centers and M is located in a bridging position between two carbon centers. These global minimum phBe/Mg clusters are highly kinetically stable against isomerization, facilitating the experimental confirmation by photoelectron spectroscopy. Noteworthy is the fact that the phBe/Mg center is linked with carbon centers through three 7c–2e delocalized σ bonds and three 7c–2e π bonds, making the cluster double aromatic (σ + π) in nature. The bonding between the Be/Mg and outer ring moiety can be best expressed as an electron-sharing σ-bond between the s orbital of Be+/Mg+ and C6M32− followed by three dative interactions involving empty pπ and two in-plane p orbitals of Be/Mg. Furthermore, Lewis basic M centers of the title clusters can be passivated through the complexation with bulky Lewis acid, 9-boratriptycene, lowering the overall reactivity of the cluster, which can eventually open up the possibility of their large-scale syntheses. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations using ab initio methods at the MRCI+Q(8,9)/def2‐QZVPPD and CCSD(T)/def2‐QZVPPD levels as well as using density functional theory are reported for the diatomic molecules AeN− (Ae=Ca, Sr, Ba). The anions CaN− and SrN− have electronic triplet (3Π) ground states with nearly identical bond dissociation energies De ~57 kcal/mol calculated at the MRCI+Q(8,9)/def2‐QZVPPD level. In contrast, the heavier homologue BaN− has a singlet (1Σ+) ground state, which is only 1.1 kcal/mol below the triplet (3Σ−) state. The computed bond dissociation energy of (1Σ+) BaN− is 68.4 kcal/mol. The calculations at the CCSD(T)‐full/def2‐QZVPPD and BP86‐D3(BJ)/def2‐QZVPPD levels are in reasonable agreement with the MRCI+Q(8,9)/def2‐QZVPPD data, except for the singlet (1Σ+) state, which has a large multireference character. The calculated atomic partial charges given by the CM5, Voronoi and Hirshfeld methods suggest small to medium‐sized Ae←N− charge donation for most electronic states. In contrast, the NBO method predicts for all species medium to large Ae→N− electronic charge donation, which is due to the neglect of the (n)p AOs of Ae atoms as genuine valence orbitals. Neither the bond orders nor the bond lengths correlate with the bond dissociation energies. The EDA−NOCV calculations show that the heavier alkaline earth atoms Ca, Sr, Ba use their (n)s and (n‐1)d orbitals for covalent bonding. [ABSTRACT FROM AUTHOR]

Background: Helicobacter pylori (H. pylori) is closely associated with gastric diseases and has a high prevalence in China. Public platforms are considered common and important tools to publicize H. pylori‐related information. This study aimed to assess and compare the content and quality of H. pylori‐related videos on TikTok and Bilibili. Materials and Methods: A search was performed on the TikTok and Bilibili platforms using the keyword "H. pylori". The source of upload was categorized as for‐profit organizations, general users, health professionals, news agencies, nonprofit organizations, and science communicators. The Journal of American Medical Association (JAMA), Global Quality Scale (GQS), and modified DISCERN scores were used to evaluate the quality of the included videos. Results: A total of 93 TikTok videos and 79 Bilibili videos were included and analyzed. TikTok videos had a significantly shorter duration than Bilibili videos (64 vs. 149 s, respectively; p < 0.001). The duration of the video showed a positive correlation with the modified DISCERN and GQS scores (p < 0.001, r = 0.388 and r = 0.437, respectively). The JAMA and modified DISCERN scores of the TikTok video were significantly higher in health professionals and nonprofit organizations than in other sources (p < 0.05). For Bilibili, science communicators had a significantly higher JAMA score than the other video sources (p < 0.001). The videos uploaded by news agencies received more views, comments, shares, and favorites than any other organization or individual (p < 0.001). Conclusions: In China, H. pylori‐related videos from TikTok and Bilibili tended to provide the information regarding the transmission and eradication of H. pylori. However, many videos scored an average rating in content and quality and need to be improved. We recommend that the public obtain H. pylori‐related information through videos uploaded by health professionals, nonprofit organizations, and science communicators. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations using ab initio methods at the MRCI+Q(6,8)/def2‐QZVPP and CCSD(T)/def2‐QZVPP levels as well as density functional theory are reported for the diatomic molecules AeB− and isoelectronic AeC (Ae=Ca, Sr, Ba). The boride anions AeB− have an electronic triplet (3Σ−) ground state. The quintet (5Σ−) state is 5.8–12.3 kcal/mol higher in energy and the singlet (1Δ) state is 13.1–15.3 kcal/mol above the triplet. The isoelectronic AeC molecules are also predicted to have a low‐lying triplet (3Σ−) state but the quintet (5Σ−) state is only 2.2 kcal/mol (SrC) and 2.9 kcal/mol (CaC) above the triplet state. The triplet (3Σ−) and quintet (5Σ−) states of BaC are nearly isoenergetic. All systems have rather strong bonds. The calculated bond dissociation energies of the triplet (3Σ−) state are between De=38.3–41.7 kcal/mol for AeB− and De=49.4–57.5 kcal/mol for AeC. The barium species have always the strongest bonds whereas the calcium and strontium compounds have similar BDEs. The bonding analysis indicates that there is little charge migration in AeB− in the direction Ae→B− where the alkaline earth atoms carry positive charges between 0.09 e–0.22 e. The positive charges at the Ae atoms are much larger in AeC where the charge migration Ae→C is between 0.90 e–0.91 e. A detailed analysis of the interatomic interactions with the EDA‐NOCV method shows that all diatomic species AeB− and AeC are built from dative interactions between Ae (1S, ns2) and B− or C (3P, 2 s22pπ12pπ′1). The eventually formed bonds in AeC are better described in terms of interactions between the ions Ae+ (2S, ns1)+C− (4S, 2 s22pπ12pπ′12pσ1). Inspection of the orbital interactions suggests that the alkaline earth atoms Ca, Sr, Ba use mainly their (n‐1)d AOs besides the (n)s AOs for the covalent bonds. This creates a second energetically low‐lying σ‐bonding MO in the molecules, which feature valence orbitals with the order ϕ1 (σ‐bonding)<ϕ2 (σ‐bonding)<ϕ3 (degenerate π‐bonding). All four occupied valence MOs of AeB− and AeC are bonding orbitals. Since the degenerate π orbitals ϕ3 are only singly occupied, the formal bond order is three. [ABSTRACT FROM AUTHOR]

To accurately diagnose the XLPE power cable insulation fault, this research proposed a novel hybrid algorithm combined with Convolutional Probabilistic Neural Network (CPNN) based on Discrete Wavelet Transform (DWT) and Symmetrized Dot Pattern (SDP) analysis. First, it built seven different power cable insulation defect models to measure partial discharge signals of power cable insulation faults. Then, a discrete wavelet transform was used for noise filtering. The time‐domain partial discharge signal was directly converted into the point coordinate feature image of visual polar coordinates by SDP analyses. Finally, the feature image was trained and recognized by CPNN. After the important feature information of the feature‐image was extracted by convolution layer and pooling layer operations, it is applied to the power cable insulation fault state diagnosis system based on the rapid learning and highly parallel computing of Probabilistic Neural Network (PNN). The experimental results proved that the method proposed in this research could accurately diagnose the power cable insulation fault type and the recognition accuracy is higher than 96%. The proposed method has a short detection time and high diagnostic accuracy. This proves that it can be applied to detect the power cable insulation fault type. [ABSTRACT FROM AUTHOR]

The global power demand is increasing year by year. Power quality fault recognition plays an important role in determining the fault type when a fault occurs, so as to maintain power quality and supply stability. Therefore, this paper proposed using the symmetrized dot pattern (SDP) algorithm plus the convolutional neural network (CNN) to study power quality fault recognition. Six common power quality fault models were taken as the subjects of discussion, including normal voltage, voltage sag, voltage swell, voltage interruptions, voltage flickers, and voltage harmonics. First, the voltage variation data of five cycles were extracted from a 60 Hz power supply and introduced into the SDP. Afterwards, the data were converted into graph data, which could be used for fault recognition. Lastly, the power quality fault type was identified by CNN. In this study, 600 random fault data (100 data per fault) were imported into the algorithm, and the recognition rate reached as high as 92.9%. Additionally, SDP could reduce the mass original data. After the subtle changes in the output signals were captured, they could be observed by images. The power quality fault state could thus be accurately recognized by CNN. [ABSTRACT FROM AUTHOR]

Because of the electron deficiency of boron, a triangular network with planar hexacoordination is the most common structural and bonding property for isolated boron clusters and two-dimensional (2D) boron sheets. However, this network is a rule-breaking structure and bonding case for all other main-group elements. Herein, the Be2M (M = Al and Ga) 2D monolayer with P6/mmm space group was found to be the lowest-energy structure with planar hexacoordinate Be/Al/Ga motifs. More interestingly, Be2Al and Be2Ga were observed to be intrinsic phonon-mediated superconductors with a superconducting critical temperature (Tc) of 5.9 and 3.6 K, respectively, where compressive strain could further enhance their Tc. The high thermochemical and kinetic stability of Be2M make a promising candidate for experimental realization, considering its high cohesive energy, absence of soft phonon modes, and good resistance to high temperature. Moreover, the feasibility of directly growing Be2M on the electride Ca2N substrate was further demonstrated, where its intriguing electronic and superconducting properties were well maintained in comparison with the freestanding monolayer. The Be2M monolayer with rule-breaking planar hexacoordinate motifs firmly pushes the ultimate connection of the "anti-van't Hoff/Le Bel" structure with promising physical properties. [ABSTRACT FROM AUTHOR]