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Plasma characteristics and material erosion mechanism in multi-channel wire electrical discharge machining

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Chinese Journal of Aeronautics 2024年第10期37卷 508-525页

作者： Guokang SU Chuanyun ZHANG Junfei LI Xiaolei CHEN Guixian LIU Yongjun ZHANG State key laboratory of Precision Electronic Manufacturing technology and Equipment Guangdong University of TechnologyGuangzhou 510006China Guangdong key laboratory of Advanced Manufacturing technology of marine Energy Equipment Guangdong University of TechnologyGuangzhou 510006China Guangzhou key laboratory of Nontraditional Machining technology and Equipment Guangdong University of TechnologyGuangzhou 510006China School of Mechanical Engineering Xi’an Technological UniversityXi’an 710021China

Multi-channel wire electrical discharge machining(MC-WEDM)is an advanced and high-efficiency machining technology,but its material erosion mechanism remains *** this study,dual-channel wire electrical discharge machining was utilized as a case study to investigate the impact of the plunging current on both the plasma characteristics and material erosion under complex discharge *** analysis was conducted on the charged particles in the plasma,revealing that the plunging current can influence the trajectory of the plasma by modifying the selfmagnetic *** particle tracking method was employed to simulate the motion of electrons,revealing that in MC-WEDM,electrons exhibited a larger and more uniform *** evolution of the plasma within a single-pulse discharge was observed using high-speed photography technology,and the discharge signals collected from different channels were *** was observed that the plasma in MC-WEDM experienced more intense back-and-forth sweeping on the workpiece surface,facilitating the ejection of molten metal from the molten *** oscillating plasma exhibits a larger processing area and a more uniform distribution of energy,resulting in the formation of larger and shallower discharge ***,the influence of the amplitude and time point of the plunging current on the volume and area of the discharge craters was ***,MC-WEDM significantly reduced the occurrence of holes and micro-cracks and exhibited a thinner recast layer in the continuous discharge experiment.

关键词： Multi-channel WEDM Discharge observation Plunging current Plasma characteristics Material erosion Discharge crater

Microstructure Features and the Macroscopic Acoustic Behavior of Gassy Silt in the Yellow River Delta

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Journal of Ocean University of China 2024年第2期23卷 371-382页

作者： LIU Tao GUO Zhenqi ZHANG Yan WU Chen LIU Lele DENG Shenggui laboratory for marine Geology Pilot National Laboratory for Marine Science and TechnologyQingdao 266061China Shandong Provincial key laboratory of marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China College of Civil Engineering Anhui Jianzhu UniversityHefei 230601China The key laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266071China College of marine Geosciences Key Laboratory of Submarine Geosciences and ProspectingOcean University of ChinaQingdao 266100China

The morphological changes in isolated bubbles in gassy silt play a critical role in the microscopic structures between soil particles and bubbles and macroscopic physical *** on X-ray CT scanning experiments under various vertical loads(four levels),self-designed acoustic macro experiments,and a series of formula revisions to the macro-air-bearing silt sound-velocity prediction model,this paper discusses the macro-and micro-scale features of gassy silts from the Yellow River *** samples consisted of different proportions of silt from the Yellow River Delta and porous media,and they were used to form two types of aerosol silts with initial gas contents of 4.23%and 7.67%.The results show that the air bubble content and external load considerably affect the microstructural parameters and acoustic behavior of gassy silt in the Yellow River *** macroscopic sound velocity showed a linear positive correlation with vertical load and relation to microstructural parameters in varying manners and *** on the traditional Biot-Stoll acoustic model,the gas-phase medium coefficient was introduced for the proper calculation and prediction of the sound velocity of air-bearing *** errors of the overall prediction varied between 5.6%and 9.6%.

关键词： gassy silt vertical load microstructure parameters bubble vibration Biot-Stoll acoustic model

The hydrophobic cluster on the surface of protein is the key structural basis for the SDS-resistance of chondroitinase VhChlABC

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marine Life Science & technology 2024年第1期6卷 93-101页

作者： Juanjuan Su Hao Wu Chengying Yin Fengchao Zhang Feng Han Wengong Yu School of Medicine and Pharmacy Ocean University of ChinaQingdao 266003China laboratory for marine Drugs and Bioproducts Qingdao Marine Science and Technology CenterQingdao 266237China key laboratory of marine Drugs Ministry of EducationQingdao 266003China Shandong Provincial key laboratory of Glycoscience and Glycoengineering Qingdao 266003China

The application of chondroitinase requires consideration of the complex microenvironment of the *** previous research reported a marine-derived sodium dodecyl sulfate(SDS)-resistant chondroitinase *** study further investigated the mechanism of VhChlABC resistance to *** on the hydrophobic cluster on its strong hydrophilic surface,it was found that the reduction of hydrophobicity of surface residues Ala181,Met182,Met183,Ala184,Val185,and Ile305 significantly reduced the SDS resistance and *** dynamics(MD)simulation and molecular docking analysis showed that I305G had more conformational flexibility around residue 305 than wild type(WT),which was more conducive to SDS insertion and *** affinity of A181G,M182A,M183A,V185A and I305G to SDS was significantly higher than that of *** conclusion,the surface hydrophobic microenvironment composed of six residues was the structural basis for SDS *** feature could prevent the binding of SDS and the destruction of hydrophobic packaging by increasing the rigid conformation of protein and reducing the binding force of *** study provides a new idea for the rational design of SDS-resistant proteins and may further promote chondroitinase research in the targeted therapy of lung diseases under the pressure of pulmonary surfactant.

关键词： Hydrophobic cluster Protein surface SDS-resistance Chondroitinase

Changes in the Boreal Summer Intraseasonal Oscillation under Global Warming in CMIP6 Models

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Advances in Atmospheric Sciences 2024年第10期41卷 1984-1998页

作者： Zhefan GAO Chaoxia YUAN key laboratory of Meteorological disaster of Ministry of Education Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersInstitute for Climate and Application Research(ICAR)Nanjing University of Information Science&TechnologyNanjing 210044China Application laboratory Japan Agency of Marine-Earth Science and TechnologyYokohama 231-0017Japan

Changes in the activities of the Boreal Summer Intraseasonal Oscillation(BSISO)at the end of 21st century under the SSP5-8.5 scenario are assessed by adopting 17 CMIP6 models and the weak-temperature-gradient *** show that the intraseasonal variations become more *** BSISO-related precipitation anomaly shows a larger zonal scale and propagates further ***,there is no broad agreement among models on the changes in the eastward and northward propagation speeds and the frequency of individual *** the western North Pacific(WNP),the BSISO precipitation variance is significantly increased,at 4.62%K^(−1),due to the significantly increased efficiency of vertical moisture transport per unit of BSISO apparent *** vertical velocity variance is significantly decreased,at−3.51%K^(−1),in the middle troposphere,due to the significantly increased mean-state static *** in the lower-level zonal wind variance are relatively complex,with a significant increase stretching from the northwestern to southeastern WNP,but the opposite in other *** is probably due to the combined impacts of the northeastward shift of the BSISO signals and the reduced BSISO vertical velocity variance under global *** in strong and normal BSISO events in the WNP are also *** show same-signed changes in precipitation and large-scale circulation anomalies but opposite changes in the vertical velocity *** is probably because the precipitation anomaly of strong(normal)events changes at a rate much larger(smaller)than that of the meanstate static stability,causing enhanced(reduced)vertical motion.

关键词： Boreal Summer Intraseasonal Oscillation global warming CMIP6 weak-temperature-gradient assumption

Provenance of colorless and brown volcanic glass in late Pleistocene tephra layers in the Western Philippine Sea

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Journal of Oceanology and Limnology 2024年第5期42卷 1438-1449页

作者： Fuqing JIANG Zhishun ZHANG Zhaohui ZHANG Guoliang ZHANG Peng HUANG Xiaojing ZHOU Zhifang XIONG Congying LI Tiegang LI key laboratory of Ocean Observation and Forecasting and key laboratory of marine Geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China laboratory for marine Geology Qingdao Marine Science and Technology CenterQingdao 266237China University of Chinese Academy of Sciences Beijing 100049China Institute of marine Chemistry and Environment Ocean CollegeZhejiang UniversityZhoushan 316021China College of marine technology and Environment Dalian Ocean UniversityDalian 116023China key laboratory of marine Sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China

Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers(T1–T4,in chronological order)containing either colorless or brown glass *** to primitive mantle,all glass shards are enriched in large-ion lithophile elements,such as Rb,Cs,and Pb,and depleted in high field-strength elements,such as Th,Nb,and Ta,indicating a subduction-related *** colorless glass shards are characterized by high SiO_(2)(>78%)and light rare earth element(LREE)contents as well as high La/Sm ratios(>9),low FeO and MgO contents(100),pointing to a rhyolitic composition and a medium-K calc-alkaline serial *** contrast,the brown glass shards are characterized by lower SiO_(2)(<63%)and LREE contents,higher FeO,MgO,and CaO contents,lower La/Sm(<6)and Ba/Th(<75),and similar Sr/Y ratios(<15),indicating derivation from medium to high-K calc-alkaline andesite *** glass shards from layers T3(152 ka)and T4(172 ka)were correlated with volcanic deposits from the Taal and Laguna Caldera in the Maccolod Corridor,respectively,while the colorless glass shards from layers T1(36.5 ka)and T2(61.2 ka)were likely sourced from the Irosin Caldera in the Bicol *** the provenance of late Pleistocene tephra layers in the western Philippine Sea is helpful to complement a Philippine volcanic history and establish a regional tephrochronostratigraphy.

关键词： volcanic glass provenance chemical composition Philippine Sea late Pleistocene

Alignment of Track Oscillations during Tropical Cyclone Rapid Intensification

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Advances in Atmospheric Sciences 2024年第4期41卷 655-670页

作者： Tong XIE Liguang WU Yecheng FENG Jinghua YU key laboratory of Meteorological disaster of Ministry of Education Nanjing University of Information Science and TechnologyNanjing 210044China Dept.of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China CMA-FDU Joint laboratory of marine Meteorology Shanghai 200438China

Recent studies on tropical cyclone(TC)intensity change indicate that the development of a vertically aligned TC circulation is a key feature of its rapid intensification(RI),however,understanding how vortex alignment occurs remains a challenging topic in TC intensity change *** on the simulation outputs of North Atlantic Hurricane Wilma(2005)and western North Pacific Typhoon Rammasun(2014),vortex track oscillations at different vertical levels and their associated role in vortex alignment are examined to improve our understanding of the vortex alignment during RI of TCs with initial hurricane *** is found that vortex tracks at different vertical levels oscillate consistently in speed and direction during the RI of the two simulated *** the consistent track oscillation reduces the oscillation tilt during RI,the reduction of vortex tilt results mainly from the mean track before *** is also found that the vortex tilt is primarily due to the mean vortex track before and after *** track oscillations are closely associated with wavenumber-1 vortex Rossby waves that are dominant wavenumber-1 circulations in the TC inner-core *** study suggests that the dynamics of the wavenumber-1 vortex Rossby waves play an important role in the regulation of the physical processes associated with the track oscillation and vertical alignment of TCs.

关键词： tropical cyclone rapid intensification vortex tilt Rossby wave

An Evaluation of Tropical Cyclone Genesis Forecast over the Western North Pacific and the South China Sea from the CMA-TRAMS

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Journal of Tropical Meteorology 2024年第1期30卷 20-28页

作者：李梦婕陈子通戴光丰田群梁卓轩林青张艳霞 Guangzhou Institute of Tropical and marine Meteorology/Guangdong Provincial key laboratory of Regional Numerical Weather prediction CMAGuangzhou 510641 China State key laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081 China Guangdong Meteorological Observatory Guangzhou 510641 China

Tropical cyclone(TC) genesis forecasting is essential for daily operational practices during the typhoon *** updated version of the Tropical Regional Atmosphere Model for the South China Sea(CMA-TRAMS) offers forecasters reliable numerical weather prediction(NWP) products with improved configurations and fine resolution. While traditional evaluation of typhoon forecasts has focused on track and intensity, the increasing accuracy of TC genesis forecasts calls for more comprehensive evaluation methods to assess the reliability of these predictions. This study aims to evaluate the effectiveness of the CMA-TRAMS for cyclogenesis forecasts over the western North Pacific and South China Sea. Based on previous research and typhoon observation data over five years, a set of localized, objective criteria has been proposed. The analysis results indicate that the CMA-TRAMS demonstrated superiority in cyclogenesis forecasts, predicting 6 out of 22 TCs with a forecast lead time of up to 144 h. Additionally, over 80% of the total could be predicted 72 h in advance. The model also showed an average TC genesis position error of 218.3 km, comparable to the track errors of operational models according to the annual evaluation. The study also briefly investigated the forecast of Noul(2011). The forecast field of the CMA-TRAMS depicted thermal and dynamical conditions that could trigger typhoon genesis, consistent with the analysis field. The 96-hour forecast field of the CMA-TRAMS displayed a relatively organized threedimensional structure of the typhoon. These results can enhance understanding of the mechanism behind typhoon genesis,fine-tune model configurations and dynamical frameworks, and provide reliable forecasts for forecasters.

关键词： CMA-TRAMS cyclogenesis numerical weather prediction tropical cyclone

Accurate Source-Receiver Positioning Method for a High-Resolution Deep-Towed Multichannel Seismic Exploration System

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Journal of Ocean University of China 2024年第2期23卷 415-426页

作者： LI Jing LIU Kai WEI Zhengrong ZHANG Liancheng LIU Yangting PEI Yanliang LIU Chenguang LIU Baohua key laboratory of marine Geology and Metallogeny First Institute of OceanographyMNRQingdao 266061China laboratory for marine Geology Laoshan LaboratoryQingdao 266061China College of Ocean Science and Engineering Shandong University of Science and TechnologyQingdao 266590China key laboratory of Fluid Transmission technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou 310018China

The near-seabed multichannel seismic exploration systems have yielded remarkable successes in marine geological disaster assessment,marine gas hydrate investigation,and deep-sea mineral exploration owing to their high vertical and horizontal ***,the quality of deep-towed seismic imaging hinges on accurate source-receiver positioning *** light of existing technical problems,we propose a novel array geometry inversion method tailored for high-resolution deep-towed multichannel seismic exploration *** method is independent of the attitude and depth sensors along a deep-towed seismic streamer,accounting for variations in seawater velocity and seabed slope *** approach decomposes the towed line array into multiline segments and characterizes its geometric shape using the line segment distance and pitch *** optimization parameters for seawater velocity and seabed slope angle,we establish an objective function based on the model,yielding results that align with objective *** the particle swarm optimization algorithm enables synchronous acquisition of optimized inversion results for array geometry and seawater *** validation using theoretical models and practical data verifies that our approach effectively enhances source and receiver positioning inversion *** algorithm exhibits robust stability and reliability,addressing uncertainties in seismic traveltime picking and complex seabed topography conditions.

关键词： high-resolution deep-towed multichannel seismic exploration source-receiver positioning array geometry inversion seawater heterogeneity seabed slope angle

Early Triassic Legoupil Formation in Schmidt Peninsula,Antarctic Peninsula:Provenance and Depositional Settings

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Journal of Earth Science 2024年第2期35卷 317-331页

作者： Chao Zhang Ying-Chun Cui Chen-Guang Liu Fang-Hua Cui Lu-Yuan Wang Wei-Qiang Zhang School of Resources and Environmental Engineering Shandong University of TechnologyZibo255049China MNR key laboratory for Polar Science Polar Research Institute of ChinaShanghai201209China key laboratory of marine Sedimentology and Environmental Geology First Institute of OceanographyState Oceanic AdministrationQingdao266061China laboratory for marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao266061China key laboratory of Mineral Resources Evaluation in Northeast Asia Ministry of Land and ResourcesChangchun130061China

Geochemical compositions can be used to determine the tectonic setting of sedimentary basins,while where the link of source to sink is no longer preserved,detrital zircon age patterns can aid in resolving the original basin *** metasedimentary Legoupil Formation,located at Cape Legoupil and the Schmidt Peninsula,could give a hint for the tectonic evolution of Antarctic *** this contribution,we constrain the sedimentary provenance of the Legoupil Formation through geochemistry and detrital zircon U-Pb *** petrography and geochemical features indicate that the provenance of the Legoupil Formation could be felsic *** zircon grains record a steady supply of Permian and Ordovician material into the Legoupil *** youngest concordant zircon ages of 262 Ma suggest that the depositional time of Legoupil Formation is no older than Late *** detrital zircon age spectrum of Legoupil Formation suggests that the Legoupil Formation sediments should be derived from regional sources endemic to western Gondwana prior to its *** with the previous studies,geochemistry and detrital zircons reflect an active continental margin tectonic setting and the detrital zircon spectra of Legoupil Formation are similar to the ones deposited in forearc tectonic setting.

关键词： Schmidt Peninsula Legoupil Formation Trinity Peninsula Group detrital zircons Antarctic Peninsula geochemistry