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Resilient satellite-based PNT system design and key technologies

Science China Earth Sciences 2025年第3期68卷 669-682页

作者： Yuanxi YANG Zheng YAO Yue MAO Tianhe XU Dixing WANG Key Laboratory of smart Earth Xi'an Research institute of Surveying and Mapping Department of Electronic engineering Tsinghua University School of Space Science and Technology Shandong University

Satellite-based positioning navigation and timing(PNT) system is the most fundamental and convenient application system in PNT fields now and in the future, thus the satellite-based PNT service system should be more and more robust, reliable and easy to be applied. Aiming at the weak service performance of the existing BeiDou constellation in the Antarctic and Arctic regions and the possible discontinuous problems in the autonomous orbit determination using BeiDou terminals on board of low earth orbit(LEO) satellites, we propose a scheme to optimize the BeiDou constellation configuration. A relatively optimized deep space PNT service constellation is designed in order to overcome the weak service capability of the BeiDou navigation constellation in deep space. We find that more satellites in the same orbital plane have better positioning geometry than increasing the number of constellation orbital planes. Furthermore, the idea of resilient satellite-based PNT service mode combining deep, high, medium, and low earth orbit navigation constellations is proposed, in order to improve the service capability of multi navigation constellations. To strengthen the satellite PNT service ability, the resilient strategies of on-board phased array antenna, on-board atomic clocks and satellite signal generator are proposed, in which the adaptively possible adjustment of signal power, signal frequency, signal modulation waveform and information format are discussed. Some examples to demonstrate the resilient satellite-based PNT application modes are given.

关键词： BeiDou navigation constellation Resilient navigation constellation Resilient PNT service Resilient signal modulation Adaptive signal power

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Adsorption Characteristics of Congo Red Dye onto Calcinated Mytilus edulis Shell Powders

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Journal of Ocean University of China 2025年第1期24卷 229-237页

作者： WANG Xin GE Xiangyun ZHU Siqi LIU Weixiang XING Ronge LI Pengcheng LI Kecheng marine Science and engineering College Qingdao Agricultural UniversityQingdao 266109China Key Laboratory of Experimental marine Biology Center for Ocean Mega-ScienceInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for marine Drugs and Bioproducts Qingdao Marine Science and Technology CenterQingdao 266237China

Dye wastewater poses a significant threat to aquatic organisms due to its high *** or eliminating the dye waste from the water is necessary for a healthy and sustainable *** study investigated the adsorption properties of Congo red dye on Mytilus edulis shell powders prepared by calcination at 500℃,700℃,and 900℃.The modified shell powder products were analyzed by SEM(scanning eletron microscopy)and FTIR(fourier transform infrared spectroscopy)for the morphology and structural *** effects of different calcination temperatures,reaction times,reaction temperatures,and initial concentration of Congo red on the adsorption properties were *** adsorption kinetics and isothermal adsorption models were also *** results revealed that the shell powder calcinated at 900℃showed the best adsorption capacity on Congo red from aqueous *** adsorption reaction reached equilibrium after 150 min and followed by the pseudo-second-order kinetic *** 25℃,96.2%of the Congo red in the solution could be removed,and the adsorption capacity could reach at least 1015 mg g^(–1).The adsorption isotherm is fit with the Freundlich model,indicating a multiphase adsorption *** results are helpful for cleaning and treating printing and dyeing effluents as well as high-value utilization of shell waste resources.

关键词： adsorption Congo red high-temperature calcination Mytilus edulis shell

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From earthquake resistance structure to earthquake resilience city–urban seismic resilience assessment

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Earthquake engineering and engineering Vibration 2025年第1期24卷 1-13页

作者： Xie Lili Zhao Yonggang Wen Weiping Zhai Changhai Key lab of Structures Dynamic Behaviour and Control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China Key lab of smart Prevention and Mitigation of Civil engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China institute of engineering Mechanics China Earthquake AdministrationHarbin 150080China

Earthquakes pose significant perils to the built environment in urban *** avert the calamitous aftermath of earthquakes,it is imperative to construct seismic resilient *** to the intricacy of the concept of urban seismic resilience(USR),its assessment is a large-scale system engineering *** assessment of USR should be based on the notion of urban seismic capacity(USC)assessment,which includes casualties,economic loss,and recovery time as *** loss is also included in the assessment of USR in addition to these *** assessment indicator system comprising five dimensions(building and lifeline infrastructure,environment,society,economy,and institution)and 20 indicators has been devised to quantify *** analytical hierarchy process(AHP)is utilized to compute the weights of the criteria,dimensions,and indicators in the urban seismic resilience assessment(USRA)indicator *** the necessary data for a city are obtainable,the seismic resilience of that city can be assessed using this *** illustrate the proposed methodology,a moderate-sized city in China was selected as a case *** assessment results indicate a high level of USR,suggesting that the city possesses strong capabilities to withstand and recover from potential future earthquakes.

关键词： urban seismic capacity urban seismic resilience assessment analytic hierarchy process functionality loss

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Experimental Study on Diesel Spray and Flame Asymmetry Characteristics of Dual-Orifice Nozzles for a Medium-Speed Engine

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Journal of Thermal Science 2025年第1期34卷 303-322页

作者： JU Dehao LIURui ZHENG Liang DENG Jiahui ZHANG Wenzheng HUO Jinlu HUANG Li Shanghai marine Diesel Engine Research institute Shanghai 201108China National Key Laboratory of marine Engine Science and Technology Shanghai 201108China Key Laboratory for Power Machinery and engineering Ministry of EducationShanghai Jiao Tong UniversityShanghai 200240China

The asymmetry of the multi-orifice spray will cause uneven heat load of the marine diesel engine,thereby affecting its working performance and service ***,an in-depth understanding of the spray and flame characteristics of multi-orifice nozzles will guide the optimization of the nozzle structure,needle design and diesel atomization and combustion *** this reason,four groups of dual-orifice nozzles with different hole diameters(0.1-0.55 mm)and mass flow rates covering the typical marine medium-speed diesel injections are designed and customized,and the constant volume chamber(CVC)with high temperature and pressure is used to simulate the actual in-cylinder working conditions of the diesel engine for the spray visualization *** study the asymmetry of the fuel sprays discharged from a diesel injector,the multi-orifice nozzle is simplified as a dual-orifice nozzle in this *** with X-ray Computed Tomography(CT)imaging technology,the influences of the nozzle internal structure on the spray and flame asymmetry are studied in the constructed supercritical *** is found that the asymmetry of the inlet angle and the equivalent length-diameter ratio is positively correlated with the inconsistency of the dual *** an increase in the injection pressure and nozzle diameter,the asymmetry of the dual spray becomes more pronounced,resulting in greater disparities in the ignition delay times and ignition positions of the two ***,the increase in nozzle diameter also leads to combustion instability,resulting in a flame with a serrated *** the increase of ambient temperature,the proportion of liquid phase in the jet decreases and the relative density of spray front decreases.

关键词： dual-orifice nozzle nozzle structure atomization spray flame asymmetry

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Ferulic acid alleviates long-term avermectin-induced damage to the spleen of carp and restores its inflammatory response and oxidative balance

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Journal of Environmental Sciences 2025年第5期151卷 616-626页

作者： Hanyu Wang Shenye Feng Enzhuang Pan Xiaomeng Ji Mengyuan Zhou Shuai Zhang Baoshi Xu Huimiao Feng Jilei Yin Zibo Dong Jiangsu Key Laboratory of marine Bioresources and Environment Co-Innovation Center of Jiangsu Marine Bio-industry TechnologyJiangsu Marine Pharmaceutical Resources Development Engineering Research CenterJiangsu Key Laboratory of Marine Pharmaceutical Compound ScreeningCollege of PharmacyJiangsu Ocean UniversityLianyungang 222005China Department of Traditional Chinese Medicine Jiangsu Union Technical Institute Lianyungang Branch institute of Traditional Chinese MedicineLianyungang 222006China

Extensive use of avermectin(AVM)in agriculture can seriously contaminate fish in *** acid(FA)is a strong antioxidant sourced from plants and is widely applied in food and medicine,but its protective function on the immunological damage caused by AVM is still *** this study,carp were chronically exposed to(1/1096 hr LC_(50))AVM for 30 day(s),with a dietary supplement of FA(400 mg/kg)to assess its effects on carp *** experimental groups(n=10)included:control,AVM-exposed(2.404μg/L),FA+AVM co-treated,and FA ***-term AVM exposure altered spleen tissue,reducing serum complement C3(p<0.01)and immunoglobulin M levels(p<0.001),and increasing proinflammatory tnf-α(p<0.001),il-6(p<0.001),il-1β(p<0.001),and inos mRNA levels,whilst down-regulating the anti-inflammatory tgf-β(p<0.05).Additionally,it disrupted the balance of oxidative stress indicators such asMDA(p<0.001),T-AOC,GSH,and CAT,leading to spleen tissue apoptosis(42.4%).However,the addition of FA reversed these conditions,elevated the anti-inflammatory factor,and improved spleen immune function following chronic exposure to AVMin ***,the ability to restore oxidative homeostasis in carp by adjusting the Nrf2/NQO-1 axis protected the health of spleen *** discovery also supports the development of fish feed for aquaculture.

关键词： Avermectin Ferulic acid Oxidative stress Inflammation response

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Platinum modification of metallic cobalt defect sites for efficient electrocatalytic oxidation of 5-hydroxymethylfurfural

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Journal of Energy Chemistry 2025年第2期101卷 463-473页

作者： Haoyu Zhan Baixue Cheng Yankun Lu Danning Xing Xingshuai Lv Huining Huang Thomas Frauenheim Tao Wang Peng Zhou State Key Laboratory of Bio-fibers and Eco-textiles College of Materials Science and Engineering Collaborative Innovation Center of Shandong Marine Biobased Fibers and Ecological Textiles Institute of Marine Biobased Materials Qingdao University Shandong institute of Advanced Technology College of Chemistry and Chemical engineering Ocean University of China Tianjin Key Laboratory of Advanced Functional Porous Materials Institute for New Energy Materials & Low-Carbon Technologies School of Materials Science and EngineeringTianjin University of Technology School of Science Constructor University Beijing Computational Science Research Center College of Chemistry and Molecular engineering Qingdao University of Science and Technology

Co3O4possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural（HMF）.However,the enrichment and activation effects of Co3O4on OH-and HMF are weak,which limits its further *** defect engineering can regulate the electronic structure,optimize the adsorption of intermediates,and improve the catalytic activity by breaking the symmetry of the material,which is rarely involved in the upgrading of *** this work,we prepare Co3O4with metal defects and load the precious metal platinum at the defect sites（PtVco）.The results of in-situ characterizatio ns,electrochemical measurements,and theoretical calculations indicate that the reduction of Co-Co coordination number and the formation of Pt-Co bond induce the decrease of electron filling in the antibonding orbitals of Co *** resulting upward shift of the d-band center of Co combined with the characteristic adsorption of Pt species synergically enhances the enrichment and activation of organic molecules and OH species,thus exhibiting excellent HMF oxidation activity(including a lower onset potential（1.14 V） and 19 times higher current density than pure Co3O4at 1.35 V).In summary,this work explores the adsorption enhancement mechanism of metal defect sites modified by precious metal in detail,provides a new option for improving the HMF oxidation activity of cobalt-based materials,broadens the application field of metal defect based materials,and gives an innovative guidance for the functional utilization of metal defect sites in biomass conversion.

关键词： Adsorption enhancement Biomass upgrading Coordination environment Electrocatalysis Metallic defect

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Efficient conversion of chitin to HMF under the cocatalytic system of formic acid and silicotungstic acid

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Journal of Oceanology and Limnology 2025年第1期43卷 261-273页

作者： Luxiao ZHOU Kun GAO Peng HE Huahua YU Ronge XING Song LIU Yukun QIN College of Chemistry and Molecular engineering Qingdao University of Science and TechnologyQingdao 266042China CAS and Shandong Province Key Laboratory of Experimental marine Biology Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for marine Drugs and Bioproducts Qingdao Marine Science and Technology CenterQingdao 266237China

The conversion process of chitin,one of the abundant biomass resources on the earth,not only follows the principles of green chemistry,but also has significant value in industrial ***,it is a great challenge to directly convert insoluble and rigid structured chitin to 5-hydroxymethylfurfural(HMF).To address this issue,we developed a green conversion process combining pretreatment and catalytic *** was first pretreated by hexafluoro isopropanol(HFIP),which somewhat disrupted the hydrogen bonding network within the chitin ***,formic acid(FA)and silicotungstic acid(STA)synergistically catalyzed the conversion to HMF in a biphasic system of 2-methyltetrahydrofuran(2-Me-THF)/H2O,and high yields(40.2%)HMF was obtained under the optimism *** product distribution was analyzed by HPLC-MS and the co-catalysis of FA with STA was evidenced.A dual-function catalytic system with both Lewis and Br?nsted acids was created,the catalytic system that significantly improved the efficiency of complex tandem catalytic reactions with *** on the experimental results,a possible pathway for chitin conversion was deduced,providing a new catalytic idea for the efficient conversion of chitin to HMF.

关键词： chitin 5-hydroxymethylfurfural 2-Me-THF/H2O biphasic system Lewis and Br?nsted acid

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Machine learning based damage state identification:A novel perspective on fragility analysis for nuclear power plants considering structural uncertainties

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Earthquake engineering and engineering Vibration 2025年第1期24卷 201-222页

作者： Zheng Zhi Wang Yong Pan Xiaolan Ji Duofa College of Civil engineering Taiyuan University of TechnologyTaiyuan 030024China Key Lab of Structures Dynamic Behavior and Control(Harbin institute of Technology) Ministry of EducationHarbin 150090China Key Lab of smart Prevention and Mitigation of Civil engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China

Seismic fragility analysis(SFA)is known as an effective probabilistic-based approach used to evaluate seismic *** are various sources of uncertainties associated with this approach.A nuclear power plant(NPP)system is an extremely important infrastructure and contains many structural uncertainties due to construction issues or structural deterioration during *** of structural uncertainties effects is a costly and time-consuming endeavor.A novel approach to SFA for the NPP considering structural uncertainties based on the damage state is proposed and *** results suggest that considering the structural uncertainties is essential in assessing the fragility of the NPP structure,and the impact of structural uncertainties tends to increase with the state of ***,machine learning(ML)is found to be superior in high-precision damage state identification of the NPP for reducing the time of nonlinear time-history analysis(NLTHA)and could be applied in the damage state-based ***,the impact of various sources of uncertainties is investigated through sensitivity *** Sobol and Shapley additive explanations(SHAP)method can be complementary to each other and able to solve the problem of quantifying seismic and structural uncertainties simultaneously and the interaction effect of each parameter.

关键词： seismic fragility analysis damage state structural uncertainties machine learning sensitivity analysis

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Enhancing microbial superoxide generation and conversion to hydroxyl radicals for enhanced bioremediation using iron-binding ligands

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Journal of Environmental Sciences 2025年第1期147卷 597-606页

作者： Yuhan Wang Xue Ning Jinsong Liang Aijie Wang Jiuhui Qu School of Civil and Environmental engineering Harbin Institute of TechnologyShenzhen 518055China SFI MaREI Centre for Energy Climate and MarineEnvironmental Research InstituteUniversity College CorkCorkIreland Center for Water and Ecology Tsinghua UniversityBeijing 100084China

Harnessing bacteria for superoxide production in bioremediation holds immense promise,yet its practical application is hindered by slow production rates and the relatively weak redox potential of *** study delves into a cost-effective approach to amplify superoxide production using an Arthrobacter strain,a prevalent soil bacterial *** research reveals that introducing a carbon source along with specific iron-binding ligands,including deferoxamine(DFO),diethylenetriamine pentaacetate(DTPA),citrate,and oxalate,robustly augments microbial superoxide ***,our findings suggest that these iron-binding ligands play a pivotal role in converting superoxide into hydroxyl radicals by modulating the electron transfer rate between Fe(Ⅲ)/Fe(Ⅱ)and ***,among the tested ligands,only DTPA emerges as a potent promoter of this conversion process when complexed with Fe(Ⅲ).We identify an optimal Fe(Ⅲ)to DTPA ratio of approximately 1:1 for enhancing hydroxyl radical production within the Arthrobacter *** research underscores the efficacy of simultaneously introducing carbon sources and DTPA in facilitating superoxide production and its subsequent conversion to hydroxyl radicals,significantly elevating bioremediation ***,our study reveals that DTPA augments superoxide production in cultures of diverse soils,with various soil microorganisms beyond Arthrobacter identified as contributors to superoxide *** emphasizes the universal applicability of DTPA across multiple bacterial *** conclusion,our study introduces a promising methodology for enhancing microbial superoxide production and its conversion into hydroxyl *** findings hold substantial implications for the deployment of microbial reactive oxygen species in bioremediation,offering innovative solutions for addressing environmental contamination challenges.

关键词： Superoxide Hydroxyl radical Iron-binding ligand Bioremediation DTPA

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Synergistic effect of silicon availability and salinity on metal adsorption in a common estuarine diatom

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Journal of Environmental Sciences 2025年第2期148卷 364-374页

作者： Fengyuan Chen Jie Ma Ke Pan SZU-HKUST Joint PhD Program in marine Environmental Science Shenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of marine Microbiome engineering Institute for Advanced StudyShenzhen UniversityShenzhen 518060China Department of Ocean Science The Hong Kong University of Science and TechnologyHong Kong 999077China

Increasing nitrogen and phosphorus discharge and decreasing sediment input have made silicon(Si)a limiting element for diatoms in *** in nutrient structure and salinity fluctuation can greatly affect metal uptake by estuarine ***,the combined effects of Si and salinity on metal accumulation in these diatoms have not been *** this study,we aimed to investigate how salinity and Si availability combine to influence the adsorption of metals by a widely distributed diatom Phaeodactylum *** data indicate that replete Si and low salinity in seawater can enhance cadmium and copper adsorption onto the diatom *** the single-cell level,surface potential was a dominant factor determining metal adsorption,while surface roughness also contributed to the highermetal loading capacity at lower *** a combination of noninvasive micro-test technology,atomic force microscopy,X-ray photoelectron spectroscopy,and Fourier transform infrared spectroscopy,we demonstrate that the diversity and abundance of the functional groups embedded in diatom cell walls vary with salinity and Si *** results in a change in the cell surface potential and transient metal *** study provides novel mechanisms to explain the highly variable metal adsorption capacity of a model estuarine diatom.

关键词： Diatom Metal adsorption Silicon Salinity Functional group Surface potential

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