21 research outputs found

    Impact and Inspiration of Tonga volcanic Eruption in 2022

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    People have been puzzled by the problem of volcanic eruptions since ancient times. Because volcanic eruptions are difficult to predict accurately, if people can't take some precautions in advance, sometimes volcanic eruptions will cause great injuries and deaths and hazards. In this context, this review selects the Tonga Volcano as the research object, summarizes the hazards during the eruption of the volcano and the symptom before the eruption, in order to get inspiration for predicting volcanic eruptions. This paper firstly introduces that Tonga volcano is located on the Tonga-Kermadec volcanic arc. When Tonga volcano erupted, it tended to an explosive eruption, which Surtseyan eruption dominated. Secondly, the author analyzes the impact on the capital of Tonga, the surrounding area and the world through the primary disaster, such as the collapse of crater, volcanic ash and SO2. Then, the global impact of secondary disasters after primary disasters is analyzed, such as tsunami and climate change. Thirdly, the author concludes the pre-eruption symptoms, such as surface deformation and ionospheric anomaly. The observation of these anomalies and the establishment of a volcano monitoring system will help people to predict the next volcanic eruption. In addition, it remains to be seen how to detect the symptoms of volcanic eruption in time. Finally, this paper emphasizes that there are few practical applications of volcano monitoring system, and more volcanoes need to be monitored in time. If volcano monitoring systems were made more common around the world, people could minimize the damage caused by volcanoes

    PTB-INRIM comparison of novel digital impedance bridges with graphene impedance quantum standards

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    This paper describes an onsite comparison of two different digital impedance bridges when performing measurements on a quantum Hall resistance standard with the purpose of realizing the SI unit of capacitance, the farad. In the EMPIR Joint Research Project 18SIB07 GIQS, graphene impedance quantum standards, the Physikalisch-Technische Bundesanstalt (PTB), Germany, developed a Josephson impedance bridge, and the Istituto Nazionale di Ricerca Metrologica (INRIM) and the Politecnico di Torino (POLITO), Italy, developed an electronic digital impedance bridge. The former is based on Josephson waveform generators and the latter on an electronic waveform synthesizer. The INRIM–POLITO impedance bridge was moved to PTB and the two bridges were compared by measuring both temperature-controlled standards and a graphene AC quantized Hall resistance (QHR) standard. The uncertainties for the calibration of 10 nF capacitance standards at 1233 Hz are within 1 × 10−8 for the PTB's bridge and around 1 × 10−7 for the INRIM–POLITO's bridge. The comparison mutually validates the two bridges within the combined uncertainty. The result confirms that digital impedance bridges allow the realization of the SI farad from the QHR with uncertainties comparable with the best calibration capabilities of the BIPM and the major National Metrology Institutes

    Development of a Bridge Management System Based on the Building Information Modeling Technology

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    With the development of the Chinese transportation industry, the number of bridges has increased significantly, but this results in high pressure of structural maintenance and management. Bridge management system (BMS) is critical for efficient maintenance and ensured safety of bridge structures during long-term operation. Building information modeling (BIM) is an emerging technology with powerful visualization and informatization capability, making it an ideal tool for developing modern management systems. This paper introduces the development of a bridge management system based on the BIM technology. Industry Foundation Classes (IFC) and International Framework for Dictionaries (IFD) standards are studied and extended, and coding rules are proposed for the Chinese bridge industry. Also, a standard structural modeling method is proposed to fast build the bridge BIM model. Web-BIM oriented bridge management is proposed, and portable devices are introduced into the system. Collaborative management is realized for different users. The BIM-based maintenance management system is designed. Finally, a practical BIM-based BMS is established for a long-span cable-stayed bridge in China. This system integrates the BIM with the geographic information system (GIS) and contains information management, inspection management, technical condition evaluation, and enables users to cooperate with each other. Such a BMS could help to improve the management efficiency and ensure its normal operation, providing a useful platform for the maintenance of massive bridges in China

    Gibberellic Acid Inhibits <i>Dendrobium nobile</i>—<i>Piriformospora</i> Symbiosis by Regulating the Expression of Cell Wall Metabolism Genes

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    Orchid seeds lack endosperms and depend on mycorrhizal fungi for germination and nutrition acquisition under natural conditions. Piriformospora indica is a mycorrhizal fungus that promotes seed germination and seedling development in epiphytic orchids, such as Dendrobium nobile. To understand the impact of P. indica on D. nobile seed germination, we examined endogenous hormone levels by using liquid chromatography–mass spectrometry. We performed transcriptomic analysis of D. nobile protocorm at two developmental stages under asymbiotic germination (AG) and symbiotic germination (SG) conditions. The result showed that the level of endogenous IAA in the SG protocorm treatments was significantly higher than that in the AG protocorm treatments. Meanwhile, GA3 was only detected in the SG protocorm stages. IAA and GA synthesis and signaling genes were upregulated in the SG protocorm stages. Exogenous GA3 application inhibited fungal colonization inside the protocorm, and a GA biosynthesis inhibitor (PAC) promoted fungal colonization. Furthermore, we found that PAC prevented fungal hyphae collapse and degeneration in the protocorm, and differentially expressed genes related to cell wall metabolism were identified between the SG and AG protocorm stages. Exogenous GA3 upregulated SRC2 and LRX4 expression, leading to decreased fungal colonization. Meanwhile, GA inhibitors upregulated EXP6, EXB16, and EXP10-2 expression, leading to increased fungal colonization. Our findings suggest that GA regulates the expression of cell wall metabolism genes in D. nobile, thereby inhibiting the establishment of mycorrhizal symbiosis

    Tailoring Permanent Charge Carrier Densities in Epitaxial Graphene on SiC by Functionalization with F4‐TCNQ

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    Abstract The outstanding properties and the potential for large‐scale fabrication open a wide field for electronic applications of epitaxial graphene on silicon carbide substrates. However, reliable doping methods to permanently control and tailor the carrier concentration to the desired value without applying an electrostatic gate are challenging and still under investigation. In this study, a post‐growth molecular doping technique is investigated that compensates for the high electron density of pristine epitaxial graphene by using the acceptor F4‐TCNQ. By precise adjustment of the dopant concentration, the carrier density can be tuned in a wide range from intrinsic n‐ to the p‐type regime. The fabricated quantum Hall devices are ready‐to‐use, and no further treatments are required. High‐precision resistance measurements of graphene‐based devices with different doping levels show a quantization accuracy of 10−9 that underlines the high quality of the fabricated devices and the suitability of this method for device applications. The experimentally observed correlation between the carrier density and the onset of the quantum Hall plateau gives a reliable criterion for the choice of devices in quantum resistance metrology

    The EMPIR Project GIQS:Graphene Impedance Quantum Standard

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    GIQS: Graphene Impedance Quantum Standard is a Joint Research Project of the European Metrology Programme for Innovation and Research (EMPIR). The project objective is to combine novel digital impedance measurement bridges with graphene-based ac quantum Hall resistance standards in a simplified cryogenic environment, to achieve simple, user-friendly quantum impedance standards suitable for primary realisation of impedance units in national metrology institutes, calibration centers, and the industry

    Clinical characteristics and risk factors of an outbreak with scrub typhus in previously unrecognized areas, Jiangsu province, China 2013.

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    Scrub typhus, caused by Orientia tsutsugamushi, has emerged recently in Jingjiang City, China where the disease had not been known to exist. We analyzed epidemiological data, clinical characteristics and risk factors of scrub typhus outbreak in Jingjiang City, 2013. The 271 clinically diagnosed patients were predominantly farmers 50 to 69 years old and the peak of onset was early to mid-November. For the 187 laboratory-confirmed cases, the major clinical manifestations of the patients were fever (100%), eschar (88.2%), rash (87.7%), chills (87.7%), and headache (66.8%). A community-based case-control study was carried out to investigate the risk factors of the scrub typhus outbreak. Bundling or moving waste straw (OR=9.0, 95%CI 4.6-17.8) and living at the edge of village (OR=0.6, 95%CI 0.4-0.9) posed the highest risks through single- and multi-variable conditional logistic regression. Phylogenetic analysis of the 56-kDa TSA gene showed that the new cluster (GB-C2) and the previously reported cluster (GB-C1) of O. tsutsugamushi were associated with this outbreak. These findings are useful for the establishment of a detailed control strategy for scrub typhus infection in previously unrecognized areas of Jiangsu Province, China
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