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基于机器学习的NWP ZTD长短期预测模型

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导航定位学报 2024年第4期12卷 34-44页

作者：白子仪徐莹冯健于浩张方照山东科技大学测绘与空间信息学院山东青岛266590 新疆维吾尔自治区地质局煤田地质中心乌鲁木齐830009 中国电子科技集团公司第三十六研究所浙江嘉兴314000

对流层延迟是影响全球卫星导航系统(GNSS)定位精度的主要误差源之一,利用数值天气预报(NWP)模型估计天顶对流层延迟(ZTD)是常用的方法之一,但NWP模型预报资料估计的ZTD精度有限;NWP模型再分析资料估计的ZTD不能用于GNSS实时定位,且目前... 详细信息

对流层延迟是影响全球卫星导航系统(GNSS)定位精度的主要误差源之一,利用数值天气预报(NWP)模型估计天顶对流层延迟(ZTD)是常用的方法之一,但NWP模型预报资料估计的ZTD精度有限;NWP模型再分析资料估计的ZTD不能用于GNSS实时定位,且目前大多数文献未能对ZTD长短期预测分别进行研究。因此,利用欧洲中期天气预报中心(ECMWF)的第五代全球气候再分析资料数据集(ERA5)和国际GNSS服务组织(IGS)的高精度ZTD数据,研究基于反向传播(BP)神经网络、支持向量机和长短期记忆网络3种机器学习算法构建以年为时间窗口的ZTD长期预测模型和以24h为时间窗口的ZTD短期预测模型的可行性。实验结果表明:构建的ZTD长期预测模型和短期预测模型可以有效提高预测ZTD的精度。

关键词：全球卫星导航系统(GNSS) 天顶对流层延迟(ZTD) 数值天气预报(NWP) 机器学习算法预测模型

Combination of Tsoft and ET34-ANA-V80 software for the preprocessing and analysis of tide gauge data in French Polynesia

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Geodesy and Geodynamics 2023年第1期14卷 26-34页

作者： Bernard Ducarme Jean-Pierre Barriot fangzhao zhang Catholic University of Louvain Georges Lemaître Centre for Earth and Climate Research(ELI)1348 Louvain-la-NeuveBelgium Geodesy Observatory of Tahiti University of French Polynesia(UPF)PunaauiaFrench Polynesia College of Geodesy and Geomatics Shandong University of Science and TechnologyQingdao 266590China

Since 2008 a network of five sea-level monitoring stations was progressively installed in French *** stations are autonomous and data,collected at a sampling rate of 1 or 2 min,are not only recorded locally,but also transferred in real time by a radio-link to the NOAA through the GOES *** new ET34-ANA-V80 version of ETERNA,initially developed for Earth Tides analysis,is now able to analyze ocean tides *** a two-step validation scheme,we took advantage of the flexibility of this new version,operated in conjunction with the preprocessing facilities of the Tsoft software,to recover co rrected data series able to model sea-level variations after elimination of the ocean tides *** performed the tidal analysis of the tide gauge data with the highest possible selectivity(optimal wave grouping)and a maximum of additional terms(shallow water constituents).Our goal was to provide corrected data series and modelled ocean tides signal to compute tide-free sea-level variations as well as tidal prediction models with centimeter *** also present in this study the characteristics of the ocean tides in French Polynesia and preliminary results concerning the non-tidal variations of the sea level concerning the tide gauge setting.

关键词： Tide gauges Tidal data processing Mean sea level

Monitoring Zenithal Total Delays over the three different climatic zones from IGS GPS final products:A comparison between the use of the VMF1 and GMF mapping functions

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Geodesy and Geodynamics 2019年第2期10卷 93-99页

作者： Benachour Labib Jianguo Yan Jean-Pierre Barriot fangzhao zhang Peng Feng State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan University Geodesy Observatory of Tahiti University of French Polynesia

The International GNSS Service(IGS) final products(ephemeris and clocks-correction) have made the GNSS an indispensable low-cost tool for scientific research, for example sub-daily atmospheric water vapor monitoring. In this study, we investigate if there is a systematic difference coming from the choice between the Vienna Mapping Function 1(VMF1) and the Global Mapping Function(GMF) for the modeling of Zenith Total Delay(ZTD) estimates, as well as the Integrated Precipitable Water Vapor(IPWV) estimates that are deduced from them. As ZTD estimates cannot be fully separated from coordinate estimates, we also investigated the coordinate repeatability between subsequent *** this purpose, we monitored twelve GNSS stations on a global scale, for each of the three climatic zones(polar, mid-latitudes and tropical), with four stations on each zone. We used an automated processing based on the Bernese GNSS Software Version 5.2 by applying the Precise Point Positioning(PPP)approach, L3 Ionosphere-free linear combination, 7 cutoff elevation angle and 2 h sampling. We noticed an excellent agreement with the ZTD estimates and coordinate repeatability for all the stations w.r.t to CODE(the Center for Orbit Determination in Europe) and USNO(US Naval Observatory) products, except for the Antarctic station(Davis) which shows systematic biases for the GMF related results. As a final step, we investigated the effect of using two mapping functions(VMF1 and GMF) to estimate the IPWV,w.r.t the IPWV estimates provided by the Integrated Global Radiosonde Archive(IGRA). The GPS-derived IPWV estimates are very close to the radiosonde-derived IPWV estimates, except for one station in the tropics(Tahiti).

关键词： International GNSS Service (IGS) Vienna Mapping Function 1 (VMF1) Global Mapping Function (GMF) Precise Point Positioning (PPP) Zenith Total Delay (ZTD) Zenith Wet Delay (ZWD) Integrated Precipitable Water Vapor (IPWV)

Gut commensal metabolite rhamnose promotes macrophages phagocytosis by activating SLC12A4 and protects against sepsis in mice

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Acta Pharmaceutica Sinica B 2024年第7期14卷 3068-3085页

作者： Dongping Li Rongjuan Wei Xianglong zhang Shenhai Gong Meijuan Wan fangzhao Wang Jiaxin Li Meiling Chen Ruofan Liu Yantong Wan Yinghao Hong Zhenhua Zeng Peng Gu zhang Wang Kutty Selva Nandakumar Yong Jiang Hongwei Zhou Peng Chen Department of Pathophysiology Guangdong Provincial Key Laboratory of ProteomicsSchool of Basic Medical SciencesSouthern Medical UniversityGuangzhou 510000China Department of Critical Care Medicine Nanfang HospitalSouthern Medical UniversityGuangzhou 510000China Department of Gastroenterology Shenzhen HospitalSouthern Medical UniversityShenzhen 518000China Institute of Ecological Sciences School of Life SciencesSouth China Normal UniversityGuangzhou 510000China Department of Environmental and Biosciences School of BusinessInnovation and SustainabilityKristian IV’s vag 3Halmstad UniversityHalmstad 30004Sweden Microbiome Medicine Center Zhujiang HospitalSouthern Medical UniversityGuangzhou 510000China

Sepsis progression is significantly associated with the disruption of gut ***,the modulatory mechanisms of gut microbiota operating during sepsis are still ***,we investigated how gut commensals impact sepsis development in a pre-clinical *** ligation and puncture(CLP)surgery was used to establish polymicrobial sepsis in *** depleted of gut microbiota by an antibiotic cocktail(ABX)exhibited a significantly higher level of mortality than *** determined by metabolomics analysis,ABX treatment has depleted many metabolites,and subsequent supplementation with L-rhamnose(rhamnose,Rha),a bacterial carbohydrate metabolite,exerted profound immunomodulatory properties with a significant enhancement in macrophage phagocytosis,which in turn improved organ damage and ***,rhamnose binds directly to and activates the solute carrier family 12(potassium-chloride symporter),member 4(SLC12A4)in macrophages and promotes phagocytosis by activating the small G-proteins,Ras-related C3 botulinum toxin substrate1(Rac1)and cell division control protein 42 homolog(Cdc42).Interestingly,rhamnose has enhanced the phagocytosis capacity of macrophages from sepsis *** conclusion,by identifying SLC12A4 as the host interacting protein,we disclosed that the gut commensal metabolite rhamnose is a functional molecular that could promote the phagocytosis capacity of macrophages and protect the host against sepsis.

关键词： Gut microbiota Sepsis Rhamnose SLC12A4 GTP-Rac1 GTP-Cdc42 Macrophage Phagocytosis

Diatomic Pd catalyst with conjugated backbone for synergistic electrochemical CO_(2)reduction

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Nano Research 2024年第6期17卷 4850-4855页

作者： Wenxuan zhang Mengran zhang Hongjuan Wang Wen zhang Min zhang MOE International Joint Laboratory of Materials Microstructure Institute for New Energy Materials and Low Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry and Chemical EngineeringTianjin University of TechnologyTianjin 300384China

Double-site catalysts have attracted widespread attention in the field of electrocatalysis due to their high metal loading,adjustable active centres,and electronic valence ***,the development of bimetallic sites catalysts that coordinate with definite atoms is still in the exploratory ***,we designed and synthesized a bimetallic palladium complex(BPB-Pd_(2))with conjugated *** supported BPB-Pd_(2)was applied to electrochemical CO_(2)reduction reaction(CO_(2)RR)for the first *** as-obtained BPB-Pd_(2)gives an exceptional Faradaic efficiency of CO(FECO)of 94.4%at−0.80 V *** hydrogen electrode(RHE),which is significantly superior to monoatomic palladium catalyst(BPB-Pd1).The density functional theory(DFT)calculations revealed that the essential reason for the outstanding activity of BPB-Pd_(2)toward CO_(2)RR was that the electronic effect between diatomic palladium reduces the free energy change for CO_(2)RR ***,BPB-Pd_(2)exhibits moderate free energy change to form COOH*intermediate,which was beneficial for the generation of CO in CO_(2)RR.

关键词： synthesis electrocatalysis CO_(2)reduction bimetallic palladium complex synergistic catalysis

N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu Yuan Yao zhang Xiaoyan zhang Junjie zhang Shen’gen zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis

Reversing free-electron transfer of sulfide cocatalyst for exceptional photocatalytic H_(2)evolution

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Journal of Materials Science & Technology 2024年第4期171卷 147-149页

作者： Yanfeng zhang Zhenyi zhang National Experimental Chemistry Teaching Center Hebei Key Laboratory of Inorganic Nano-materialsCollege of Chemistry and Materials ScienceHebei Normal UniversityShijiazhuang 050024China Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning ProvinceSchool of Physics and Materials EngineeringDalian Minzu UniversityDalian 116600China

Recently,Yu and co-workers deeply explore the potential impact of free electron transfer between co-catalysts and photocatalyst carriers on H_(2)evolution efficiency of active sites over MoS_(2+x).They pro-pose an electron-reversal tactics to evade the unexpected electron transfer and synchronously regulate the above transfer in a beneficial orientation for weakening hydrogen adsorption on S ***,this highlight not only discusses and summarizes the essences of electron reversal and the optimized H ad-sorption/desorption mechanism,but also emphasizes the significance of femtosecond transient absorp-tion spectroscopy(fs-TAS)and in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)for revealing charge transfer dynamics and *** anticipate that this highlight can disseminate a new per-spective on the roles of photocatalyst carriers in improving cocatalytic H_(2)-production kinetics.

关键词： Photocatalysis Cocatalyst Electron reversal Antibonding-orbital occupancy S–H bonds

Friction as energy dissipation process associated with superlubricity of solids

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Friction 2024年第9期12卷 2083-2088页

作者： Bo zhang Saga University Saga-shi 840-8502Japan

The paper shows that work in a quantum system is quantized with energy;the quantum work is equivalent to the highest eigenenergy(the Debye energy)of the system and the superlubricity of solids is derived from the quantum *** prerequisite for the superlubricity is that the lateral force at contact surfaces in sliding is less than the Debye force so that the phonon of the solids is not excited.

关键词： superlubricity phonon friction Plank law Debye frequency

Inter-well internal resonance analysis of rectangular asymmetric cross-ply bistable composite laminated cantilever shell under transverse foundation excitation

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1353-1370页

作者： Lele REN Wei zhang Yufei zhang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanics Guangxi UniversityNanning 530004China Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures College of Mechanical EngineeringBeijing University of TechnologyBeijing 100124China

The chaotic dynamic snap-through and complex nonlinear vibrations are investigated in a rectangular asymmetric cross-ply bistable composite laminated cantilever shell,in cases of 1:2 inter-well internal resonance and primary *** transverse foundation excitation is applied to the fixed end of the structure,and the other end is in a free *** first-order approximate multiple scales method is employed to perform the perturbation analysis on the dimensionless two-degree-of-freedom ordinary differential motion control *** four-dimensional averaged equations are derived in both polar and rectangular coordinate *** from the obtained frequency-amplitude and force-amplitude response curves,a detailed analysis is conducted to examine the impacts of excitation amplitude,damping coefficient,and tuning parameter on the nonlinear internal resonance characteristics of the *** nonlinear softening characteristic is exhibited in the upper stable-state,while the lower stable-state demonstrates the softening and linearity *** simulation is carried out using the fourth-order Runge-Kutta method,and a series of nonlinear response curves are *** the excitation amplitude further elucidates the global bifurcation and chaotic dynamic snap-through characteristics of the bistable cantilever shell.

关键词： bistable composite laminated cantilever shell inter-well internal resonance primary resonance chaotic dynamic snap-through complex nonlinear vibration