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Orbit and clock products for quad-system satellites with undifferenced ambiguity fixing approach

Satellite Navigation 2024年第1期5卷 125-139页

作者： Jiaqi wu Xingxing Li Yongqiang Yuan Keke Zhang Xin Li Jiaqing Lou Yun xiong School of Geodesy and Geomatics Wuhan University129 Luoyu RoadWuhan430079China Hubei Luojia Laboratory 129 Luoyu RoadWuhan430079China German Research Centre for Geosciences GFZ Telegrafenberg14473PotsdamGermany Technische Universitat Berlin(TUB) Straße Des 17.Juni10623BerlinGermany

Integer Ambiguity Resolution(IAR)can significantly improve the accuracy of GNSS Precise Orbit Determination(POD).Traditionally,the IAR in POD is achieved at the Double Differenced(DD)*** this contribution,we develop an Un-Differenced(UD)IAR method for Global Positioning System(GPS)+BeiDou Navigation Satellite System(BDS)+Galileo navigation satellite system(Galileo)+Global'naya Navigatsionnaya Sputnikovaya Sistema(GLONASS)quad-system POD by calibrating UD ambiguities in the raw carrier phase and generating the so-called carrier *** on this method,we generate the UD ambiguity-fixed orbit and clock products for the wuhan Innovation Application Center(IAC)of the International GNSS Monitoring and Assessment System(iGMAS).One-year observations in 2020 from 150 stations are employed to investigate performance of orbit and clock ***,the UD Ambiguity Resolution(AR)yields more resolved integer ambiguities than the traditional DD AR,scaling up to 9%,attributable to its avoidance of station baseline *** from the removal of ambiguity parameters,the computational efficiency of parameter estimation undergoes a substantial 70%*** with the float solution,the orbit consistencies of UD AR solution achieve the accuracy of 1.9,5.2,2.8,2.1,and 2.7 cm for GPS,BeiDou-2 Navigation Satellite System(BDS-2),BeiDou-3 Navigation Satellite System(BDS-3),Galileo,and GLONASS satellites respectively,reflecting enhancements of 40%,24%,54%,34%,and 42%.Moreover,the standard deviations of Satellite Laser Ranging(SLR)residuals are spanning 2.5–3.5 cm,underscoring a comparable accuracy to the DD AR solution,with discrepancies below 5%.A notable advantage of UD AR lies in its capability to produce the Integer Recovered Clock(IRC),facilitating Precise Point Positioning(PPP)AR without requiring additional Uncalibrated Phase Delay(UPD)*** assess the performance of quad-system kinematic PPP based on IRC,a network comprising 120 stations is uti

关键词： Multi-GNSS Precise orbit determination Integer recover clock Undifferenced ambiguity resolution iGMAS innovation application center

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Productivity in the Southern Ocean Antarctic Zone during the Northern Hemisphere Glaciation(NHG)and its link to atmospheric pCO_(2)

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Science China Earth Sciences 2024年第7期67卷 2242-2252页

作者： Yiming wu Jingteng GUO Xiangyu ZHAO Wenshen XIAO Heng LIU Zhifang xiong Tiegang LI Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Laoshan LaboratoryQingdao 266237China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China Key Laboratoryof Polar Ecosystem and Climate Change Shanghai Jiao Tong UniversityMinistry of EducationShanghai 200030China State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China

A decrease in atmospheric CO_(2)partial pressure(pCO_(2))is considered an important prerequisite for the onset and intensification of Northern Hemisphere Glaciation(NHG).However,how the ocean sequestered missing CO_(2)during the NHG is still *** in surface productivity and deep ventilation in the Southern Ocean(SO)have been proposed to explain the variations in atmospheric pCO_(2)over the last eight glacial cycles,but it is unclear whether these mechanisms contributed to the decrease in atmospheric pCO_(2)during the *** titanium-normalized contents and mass accumulation rates of biogenic opal and total organic carbon from the International Ocean Discovery Program(IODP)Expedition 374 Site U1524A,we reconstruct the productivity in the Ross Sea,Antarctica,from 3.3 Ma to 2.4 *** productivity records exhibit a long-term decreasing trend and several distinct phased evolutionary ***,the local productivity fluctuated dramatically during 3.3-3.0 Ma,decreased gradually during 3.0-2.6 Ma,and remained relatively constant during 2.6-2.4 *** comparing productivity with its potential influences,we infer that the phased and long-term evolutions of productivity were mainly controlled by changes in deep ocean *** ice expansion might have decreased productivity during 3.3-3.0 Ma by light *** in eolian dust input have little effect on *** analysis revealed no coupling linkage between productivity and atmospheric pCO_(2),indicating that the productivity in the SO Antarctic Zone(AZ)was not the main factor controlling the atmospheric CO_(2)decrease during the *** improve our understanding of the role of SO processes in the NHG,further studies should focus on the potential influences of deep ocean ventilation on atmospheric pCO_(2)in the AZ,and similar studies should also be extended to the sea area in the Subantarctic Zone.

关键词： Ross Sea Biogenic opal Total organic carbon Deep ocean ventilation Sea ice Ocean carbon cycle

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Dynamics of an impurity ion transport in oil-paper insulation under various electric fields

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High Voltage 2024年第1期9卷 66-80页

作者： Yuanyang Ren Yang Wang Qiankai Zhang Jiayu xiong Wen Cao Zepeng Lv Kai wu State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina School of Electronics and Information Xi'an Polytechnic UniversityXi'anChina State Grid Sichuan Electric Power Research Institute ChengduChina

The ionic transport process is an important counterpart to charge transport in oil-paper insulation,and it significantly impacts oil flow electrification at the oil-paper *** this,the dynamics of this phenomenon and the underlying mechanisms remain unclear,particularly at the molecular *** understand this fundamental aspect,we conduct Molecular Dynamics study on the transport behaviour of an impurity ion in different oil-paper insulation models under various external electric *** influence factors,such as external electric fields,temperatures,and local structural characteristics,are investigated in relation to the corresponding ionic mobility in different polymer *** to the simulations,ionic mobility and its response to electric fields are higher in weaker electrostatic *** a result,mineral oil exhibits the highest ionic mobility and the most substantial enhancement of ionic mobility by external electric fields,followed by vegetable oil,oil-paper blends,and insulating *** significant deviation in ionic mobility between oil and paper leads to the formation of an electric double layer near the oil-paper *** underlying physical mechanisms of different ionic mobility and its response to the electric field in different polymer models could be explained by the different polymer structural influences in terms of interaction energy and coordination numbers in a static manner,as well as by the interactions between the impurity ion and its surrounding atoms in terms of lifetime correlation functions and velocity autocorrelation functions in a dynamic *** addition,the influence of temperature on ionic mobility in mineral and vegetable oil is examined,and their activation energies are *** in the fundamental understanding of the dynamics of the ion transport process in oil-paper insulation is vital to improving their insulating properties for oil-impregnated power transformers.

关键词： insulation transport fields

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Nitrogen–sulfur co-doped porous carbon derived from asphalt as efficient catalyst for oxygen reduction

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Rare Metals 2024年第1期43卷 380-388页

作者： Jing-Sheng Ma Ming-Zai wu Ling Chen Li-Xing Zhang Ying xiong Key Laboratory of Structure and Functional Regulation of Hybrid Materials Ministry of EducationInstitute of EnergyHefei Comprehensive National Science CenterAnhui UniversityHefei 230601China

As an environment-friendly and low-cost petrochemical by-product, asphalt has great potential in the preparation of metal-free oxygen reduction electrocatalysts with excellent performance and outstanding stability. In this paper, we converted asphalt into porous carbon nanosheets by a simple activation method, using potassium citrate as the swelling agent.

关键词： stability porous catalyst

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A breathable, designable and flexible leather–heater used in wearable thermotherapy

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Science China(Technological Sciences) 2024年第7期67卷 2125-2132页

作者： ZHU JingYu LIU YaDong XIE RuiJie ZHAO YuHan WANG Feng LIU YunQing ZHA BaoLi wu JianSheng huo FengWei Key Laboratory of Flexible Electronics(KLOFE) School of Flexible Electronics(Future Technologies)Institute of Advanced Materials(IAM)Nanjing Tech UniversityNanjing 211816China The Institute of Flexible Electronics(IFE Future Technologies)Xiamen UniversityXiamen 361005China Tan Kah Kee Innovation Laboratory Xiamen 361102China

Flexible heaters with personal thermal management capabilities have great potential in thermal therapy applications due to their excellent flexibility, low power consumption, and portability. However, manufacturing wearable heating devices that are breathable, wear resistant and conformal for long-term use is still challenging. To address these issues, we designed a leather heater using breathable, biocompatible, and tailorable leather as the substrate through a simple in-situ polymerization polypyrrole strategy. This heater exhibits excellent heating and mechanical properties(reaching 64℃ at a voltage of 5 V with efficient Joule heat generation of 2286 W/m^(2)and uniform temperature distribution, and functioning properly after 1000 cycles of bendability tests). In addition, this heater displays better wear resistance and water vapor permeability rate(38.04 g/(m^(2)h)). The cuttable and sewable of leather gives the strategy ability to be flexibly designed to mold the heater to the specific requirements of different body parts, providing a new approach to wearable thermal therapy.

关键词： flexible electronics leather thermotherapy

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Boosting thermal stability and crystallization of closed-loop-recyclable biodegradable poly(p-dioxanone) by end-group regulation

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Science China Chemistry 2024年第2期67卷 642-651页

作者： Jin Lei Zhu-Xin Gui Wan-Ting xiong Gang wu Si-Chong Chen Yu-Zhong Wang The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials(MoE) National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan)State Key Laboratory of Polymer Materials EngineeringCollege of ChemistrySichuan UniversityChengdu610064China

A chemically closed-loop-recyclable biodegradable polymer,poly(p-dioxanone)(PPDO),is one of the ideal candidates for single-use plastic products due to its suitability for different application ***,when PPDO wastes can be collected,its monomer p-dioxanone(PDO) will be obtained through chemical recycling of these wastes;when cannot be collected,the wastes are able to be biodegraded into harmless ***,unsatisfied thermal stability and low crystallization rate of PPDO restrict its wider ***,based on end-group regulation,we simultaneously realized the significant enhancement of thermal stability and crystallization of PPDO through the simple melt processing with tributyl phosphite(TBP) or triphenyl phosphite(TPP).The model reactions were conducted to investigate the reaction mechanism and theoretical products during the preparation of PPDO/phosphite *** kinds of phosphites were proved to act as the end-capped reagent and chain extender in the melt processing,while TBP presented better *** a result,the activation energy of thermal decomposition was largely elevated,and the unprecedented T_(5%)(the temperature at a weight loss of 5%) and Tmax(the temperature at a maximum rate of weight loss) of PPDO were obtained,i.e.,T_(5%)of ~330 ℃ and Tmaxof ~385 ℃ in N_(2) atmosphere,T_(5%)of ~240 ℃ and Tmaxof ~317 ℃ in air atmosphere,***,the increased crystallization rate,crystallinity,crystalline orderliness,and realizable monomer recovery(yield >90%,purity >99.9%) of PPDO/phosphite compounds were confirmed.

关键词： poly(p-dioxanone) phosphite thermal stability crystallization end-group regulation

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CHD4-induced up-regulation of ERα activity contributes to breast cancer progression

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Genes & Diseases 2024年第3期11卷 132-135页

作者： Aman Sattout Xiaomin Yu Zhuo Sun Yanan Li Yulin Li Shujing Li Wei huo Huijian wu School of Bioengineering&Key Laboratory of Protein Modification and Disease Liaoning ProvinceDalian University of TechnologyDalianLiaoning 116024China Department of Oncology Central Hospital Affiliated with Dalian University of TechnologyDalianLiaoning 116089China

The estrogen signaling system is a crucial regulator of ***,abnormal activation of estrogen signaling may play a role in breast cancer initiation and *** to this pathway is the interaction between estrogen receptor alpha(ERa)and various co-transcription activators.1 Although numerous studies have investigated ER coregulators,the protein-protein interaction networks of ERa are not fully *** research has shown that high chromodomain helicase DNA-binding 4(CHD4)expression is linked to poor prognosis in various cancers.2,?In this study,we demonstrated that both CHD4 and ERαcontribute to breast cancer progression while providing evidence of the regulatory processes and functional interplay between these two proteins.

关键词： breast cancer ERα

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Pure-high-even-order dispersion bound solitons complexes in ultra-fast fiber lasers

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Light(Science & Applications) 2024年第5期13卷 957-972页

作者： Ying Han Bo Gao Honglin Wen Chunyang Ma Jiayu huo Yingying Li Luyao Zhou Qi Li Ge wu Lie Liu College of Communication Engineering Jilin UniversityChangchun 130012China. Research Center of Circuits and Systems Peng Cheng LaboratoryShenzhen 518055China. International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China. College of Electronic Science and Engineering Jilin UniversityChangchun 130012China

Temporal solitons have been the focus of much research due to their fascinating physical *** solitons can form bound states,which are fundamentally crucial modes in fiber laser and present striking analogies with their matter molecules counterparts,which means they have potential applications in large-capacity transmission and alloptical information *** traditionally,second-order dispersion has been the dominant dispersion for conventional solitons,recent experimental and theoretical research has shown that pure-high-even-order dispersion(PHEOD)solitons with energy-width scaling can arise from the interaction of arbitrary negative-even-order dispersion and Kerr *** these advancements,research on the bound states of PHEOD solitons is currently *** this study,we obtained PHEOD bound solitons in a fiber laser using an intra-cavity spectral pulse shaper for high-order dispersion ***,we experimentally demonstrate the existence of PHEOD solitons and PHEOD bound solitons with pure-quartic,-sextic,-octic,and-decic *** simulations corroborate these experimental ***,vibrating phase PHEOD bound soliton pairs,sliding phase PHEOD bound soliton pairs,and hybrid phase PHEOD bound tri-soliton are discovered and *** results broaden the fundamental understanding of solitons and show the universality of multi-soliton patterns.

关键词： dispersion solitons soliton

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Experimental investigation on shear strength deterioration at the interface between different rock types under cyclic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3063-3079页

作者： Qiong wu Zhiqi Liu Huiming Tang Liangqing Wang Xiaoxue huo Zhen Cui Shiyu Li Bo Zhang Zhiwei Lin Faculty of Engineering China University of GeosciencesWuhan430074China Guangxi Fangchenggang Beitou Environmental Protection Water Co. Ltd.Fangchenggang538021China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of *** this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold *** shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear *** results indicate that the shear stress *** displacement curves under each shear cycle and the peak shear strength *** number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with *** peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing *** normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate.

关键词： Discontinuities with different joint wall material(DDJM) Discontinuities with identical joint wall material(DIJM) Cyclic shear test Shear strength deterioration Joint surface morphology Shear displacement amplitude Shear rate Normal stress

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Synergistic Promotion of Electrical, Mechanical and Thermal Properties for Silicone Rubber-based Field Grading Material via Compound Modification

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 337-350页

作者： Jiale wu Yangzhi Gong Peiqi xiong Zexi Xing Xiaofeng Xue Xiao Yang Boyang Shen Xingming Bian State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University102206 BeijingChina State Grid Fuzhou Electric Power Supply Company Fuzhou 350009Fujian ProvinceChina Electrical Engineering Division University of CambridgeCambridge CB30FAUK

Use of nonlinearconductive SiC/silicone rubber(SR)field grading material(FGM)can improve the local field concentration of composite *** large volume fraction and large-size SiC particles(SiCp)into SR can obtain a good field grading effect,but it is accompanied by the deterioration of mechanical *** SiC with different shapes can solve this *** incorporating one-dimensional SiC whiskers(SiCw)to synergize with granular SiCp,SiC/SR FGM with better field-dependent conductivity,mechanical properties and thermal conductivity than large-size SiCp and large volume fraction filling case can be obtained by using smaller size SiCp and lower filling *** simulations of 500 kv line insulators show that the modified SiC/SR FGM can reduce the maximum field strength along the insulator surface and at sheath-core rod interfaces by 55%and 71.4%,*** combined application of FGM and grading ring can achieve a complementary *** FGM to partially replace the role of the grading rings,the field strength indicators can still meet the operational requirements after the tube radius and shielding depth of the grading rings at both ends are reduced by 36.2%and 40%separately,which is a benefit to alleviating the problems of high weight and large volume faced by traditional field grading methods.

关键词： Compound modification electric field regulation field grading material field-dependent conductivity mechanical properties thermal conductivity

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