Space charge dynamics in oil-impregnated pressboard under AC electric field

Space charge has been a general concern related with the reliability and the life-time of HVDC components. In this present work, the space charge profiles in oil-impregnated pressboards are investigated by the means of the pulsed electroacoustic (PEA) technique under AC voltage with 50 Hz at the room temperature. It has been observed that the ageing status of the mineral oil and the presence of the oil gap can influence the charge accumulation significantly. In the fresh oil impregnated pressboard, considerable negative charges are accumulated near the aluminium electrode. However, only little or no space charge can be detected in the aged oil impregnated pressboard and the oil gap and pressboard composite insulation system. The results may suggest that the amount of the AC space charge is highly dependent on the charge mobility within the dielectrics. The higher charge mobility can result in a smaller amount of AC space charge

Quarkyonic matter and quarkyonic stars in an extended RMF model

By combining RMF models and equivparticle models with density-dependent quark masses, we construct explicitly ``a quark Fermi Sea'' and ``a baryonic Fermi surface'' to model the quarkyonic phase, where baryons with momentums ranging from zero to Fermi momentums are included. The properties of nuclear matter, quark matter, and quarkyonic matter are then investigated in a unified manner, where quarkyonic matter is more stable and energy minimization is still applicable to obtain the microscopic properties of dense matter. Three different covariant density functionals TW99, PKDD, and DD-ME2 are adopted in our work, where TW99 gives satisfactory predictions for the properties of nuclear matter both in neutron stars and heavy-ion collisions and quarkyonic transition is unfavorable. Nevertheless, if PKDD with larger slope of symmetry energy $L$ or DD-ME2 with larger skewness coefficient $J$ are adopted, the corresponding EOSs are too stiff according to both experimental and astrophysical constraints. The situation is improved if quarkyonic transition takes place, where the EOSs become softer and can accommodate various experimental and astrophysical constraints

Language Embedded 3D Gaussians for Open-Vocabulary Scene Understanding

Open-vocabulary querying in 3D space is challenging but essential for scene understanding tasks such as object localization and segmentation. Language-embedded scene representations have made progress by incorporating language features into 3D spaces. However, their efficacy heavily depends on neural networks that are resource-intensive in training and rendering. Although recent 3D Gaussians offer efficient and high-quality novel view synthesis, directly embedding language features in them leads to prohibitive memory usage and decreased performance. In this work, we introduce Language Embedded 3D Gaussians, a novel scene representation for open-vocabulary query tasks. Instead of embedding high-dimensional raw semantic features on 3D Gaussians, we propose a dedicated quantization scheme that drastically alleviates the memory requirement, and a novel embedding procedure that achieves smoother yet high accuracy query, countering the multi-view feature inconsistencies and the high-frequency inductive bias in point-based representations. Our comprehensive experiments show that our representation achieves the best visual quality and language querying accuracy across current language-embedded representations, while maintaining real-time rendering frame rates on a single desktop GPU

Breakdown voltage of ultrathin dielectric film subject to electrostatic discharge stress

Ultrathin silicon oxide film for nano-electromechanical system (NEMS) applications is investigated under electrostatic discharge (ESD) stress using a transmission line pulse (TLP) tester. The measured breakdown voltage and transient response are analyzed. The results show that the voltage stress time has a significant effect on the breakdown voltage. By shortening the stress time, the breakdown voltage increases by 2–3 times. With the area shrinking breakdown voltage increases, and there is a critical value, below which the breakdown voltage increases dramatically with decreasing area. It is possible to enhance the ESD robustness by using a multiple small-area dielectric layer structure. Shorten ESD pulse rise-time induces a higher overshoot current and then accelerates oxide failure, resulting in a lower breakdown voltage for a faster pulse

BakedAvatar: Baking Neural Fields for Real-Time Head Avatar Synthesis

Synthesizing photorealistic 4D human head avatars from videos is essential for VR/AR, telepresence, and video game applications. Although existing Neural Radiance Fields (NeRF)-based methods achieve high-fidelity results, the computational expense limits their use in real-time applications. To overcome this limitation, we introduce BakedAvatar, a novel representation for real-time neural head avatar synthesis, deployable in a standard polygon rasterization pipeline. Our approach extracts deformable multi-layer meshes from learned isosurfaces of the head and computes expression-, pose-, and view-dependent appearances that can be baked into static textures for efficient rasterization. We thus propose a three-stage pipeline for neural head avatar synthesis, which includes learning continuous deformation, manifold, and radiance fields, extracting layered meshes and textures, and fine-tuning texture details with differential rasterization. Experimental results demonstrate that our representation generates synthesis results of comparable quality to other state-of-the-art methods while significantly reducing the inference time required. We further showcase various head avatar synthesis results from monocular videos, including view synthesis, face reenactment, expression editing, and pose editing, all at interactive frame rates.Comment: ACM Transactions on Graphics (SIGGRAPH Asia 2023). Project Page: https://buaavrcg.github.io/BakedAvata

Evaluation of geo-hazard risks in the pearl river delta based on geographic information system and weighted informativeness approach

The implementation of the provincial geo-hazard risk survey in China holds significant guiding importance in assessing disaster risks on a large scale and across different regions. Taking the Pearl River Delta (PRD) in Guangdong Province as a case study, characterized by a highly developed economy and dense population yet facing challenges from geo-hazard, this study utilizes the risk assessment system for geo-hazard along with a substantial dataset on hidden dangers. The hazardousness levels, vulnerability, and overall risk are evaluated by applying the risk matrix method, Weighted Informativeness method, and grey correlation analysis method. The results indicate that: (1) The level of hazardousness posed by geo-hazards in the PRD is typically more pronounced in the central and eastern areas, while it is lower in the western regions. The severity of geo-hazards is primarily influenced by rainfall factors, while there is no direct correlation between slope factors and the occurrence of geo-hazards. The relationship between altitude and the likelihood of geo-hazards typically indicates that higher altitudes pose a greater risk. However, this pattern does not hold for the PRD; (2) The susceptibility to geo-hazard in the PRD is intricately linked to the level of regional economic advancement, with areas of medium to high vulnerability predominantly clustered around Guangzhou, Shenzhen, and Dongguan; (3) The likelihood of geo-hazard in the PRD, with a higher risk observed in the central part and lower risk in the surrounding areas, displaying a radial distribution pattern. Rainfall patterns and the level of economic development in the region significantly influence the assessment of geo-hazard risks in the PRD

Use of serial analysis of gene expression to reveal the specific regulation of gene expression profile in asthmatic rats treated by acupuncture

<p>Abstract</p> <p>Background</p> <p>Asthma has become an important public health issue and approximately 300 million people have suffered from the disease worldwide. Nowadays, the use of acupuncture in asthma is increasing. This study intended to systematically analyze and compare the gene expression profiles between the asthmatic and acupuncture-treated asthmatic rat lung, and tried to gain insight into the molecular mechanism underlying the early airway response (EAR) phase of asthma treated by acupuncture.</p> <p>Methods</p> <p>Four tag libraries of serial analysis of gene expression (SAGE) were established from lung tissues of control rats (CK), asthmatic rats (AS), asthmatic rats treated by acupuncture (ASAC), and control rats treated by acupuncture (CKAC). Bioinformatic analyses were carried out by using the methods including unsupervised hierarchical clustering, functional annotation tool of the database for annotation, visualization, and integrated discovery (DAVID), gene ontology (GO) tree machine, and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis.</p> <p>Results</p> <p>There were totally 186 differentially expressed tags (P < 0.05, P_CK/AS) between the libraries of CK and AS, 130 differentially expressed tags between libraries of AS/ASAC (P < 0.05, P_AS/ASAC), and 144 differentially expressed tags between libraries of CK/CKAC (P < 0.05, P_CK/CKAC). The gene expression profiles of AS and ASAC were more similar than other libraries via unsupervised SAGE clustering. By comparison of P_CK/ASand P_AS/ASAC, the DAVID genes functional classification was found to be changed from "immune response" to "response to steroid hormone stimulus", and the GO term "antigen processing and presentation of peptide antigen" disappeared in P_AS/ASAC. Totally 3 same KEGG pathways were found among the three groups. Moreover, 21 specific tags of the acupuncture in treating asthma were detected using Venn diagrams.</p> <p>Conclusion</p> <p>Our SAGE research indicates that the gene expression profile of the EAR phase of asthma could be effectively and specifically regulated by acupuncture, which suggests that the gene expression of immune response and steroid hormone may play an important role in the treatment.</p