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The Unsymmetrical Delay Compensation in WDM time Transmission Using Optical Fiber

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The Unsymmetrical Delay Compensation in WDM Time Transmissio...

第三届中国卫星导航学术年会

作者： Li xiaofeng 1,2,3 ,Liang Shuangyou 1,2 ,Chen Faxi 1,2 ,Zhao Kan 1,2 ,Zhang Shougang 1,2 1 national time service center,chinese academy of sciences.xi’an,Shaanxi,710600, china 2 Key Laboratory of time and Frequency Primary Standards,national time service center, chinese academy of sciences.xi’an,Shaanxi,710600,china 3 Graduate University of chinese academy of sciences.Beijing,100049,china

The transmission of optical wave in fiber is analyzed,and the asymmetry of transmission delay which results from phenomena of chromatic dispersion is computed under the condition of DWDM（density WDM）and SWDM（sparse WDM）.Then we proposed a scheme of DWDM transmission delay compensation in time transmission using optical *** theoretical calculation shows that when calculated on 50km transmission range,the time difference when using two waves of wavelength difference of 1nm is nearly three orders of magnitude less than when using two waves of wavelength of 1550nm and 1310nm.

关键词： time transmission optical fiber time delay compensation WDM

Heterogeneous MXene-based films with graded electrical conductivity towards highly efficient EMI shielding and electrothermal heating

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Nano Research 2024年第8期17卷 7264-7274页

作者： Yu Zhang Guangcheng Zhang Zhonglei Ma Jianbin Qin xi Shen Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Research Institute for Sports Science and Technology The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

The increasing need for electromagnetic interference(EMI)shielding of electronics in cold environments such as those in aircraft,space exploration,and wearable heaters to avoid hazardous icing conditions or hypothermia requires the development of thin and lightweight EMI shielding materials preferably by absorbing rather than reflecting electromagnetic(EM)waves while also generating heat through energy-efficient electrothermal ***,it is challenging to achieve absorption-dominant EMI shielding and energy-efficient electrothermal heating simultaneously in a thin and lightweight ***,we develop a heterogeneous composite film comprising a porous multi-walled carbon nanotubes(MWCNTs)/bacterial cellulose(BC)film and an aligned MXene/Ag nanowires(NWs)backing via a sequential vacuum filtration *** porous film contains random conductive networks of MWCNTs with moderate conductivity while the aligned MXene sheets atop Ag NWs network affords high conductivity in the backing,giving rise to graded electrical conductivity for absorption-dominant EMI *** increasing Ag NW coverage leads to significantly increased electrical conductivity without increasing the EM wave reflection as well as the density and thickness of the film,yielding excellent specific EMI shielding effectiveness(>8500 dB/(g·cm^(2))),low driving voltage for energy-efficient electrothermal heating(163℃at 2.5 V),and fast response time(60 s)at a low areal density of 0.015 mg/cm^(2).Combining EMI shielding and electrothermal heating,the heterogeneous film developed here are promising contenders for the protection of electronic equipment in low-temperature environment.

关键词： heterogenous composite film MXene electromagnetic interference(EMI)shielding thermal management

Enhancing electrochemical capacity and interfacial stability of lithium-ion batteries through side reaction modulation with ultrathin carbon nanotube film and optimized lithium cobalt oxide particle size

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Nano Research 2024年第8期17卷 7230-7241页

作者： Wei xi xiaogang xia Jiacheng Zhu Dehua Yang Sishen xie Beijing national Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China School of Physical sciences University of Chinese Academy of SciencesBeijing 100049China Advanced Passivation Technology Lab College of Physics Science and TechnologyHebei UniversityBaoding 071002China

Lithium cobalt oxide(LCO),the first commercialized cathode active material for lithium-ion batteries,is known for high voltage and ***,its application has been limited by relatively low capacity and stability at high *** particle size is considered one of the most straightforward and effective strategies to enhance ion transfer,thus increasing the rate ***,side reactions are simultaneously enhanced as the specific surface area ***,we investigate the impact of LCO particles with varying size distributions and optimize the particle *** modulate the side reactions associated with particle size reduction,an ultrathin carbon nanotube film(UCNF)is introduced to coat the cathode *** this simple process and optimized particle size,the rate performance improves significantly,normal commercial LCO achieves 118 mA·h·g^(−1)at 3.0–4.3 V and 20 C(0.72 mA·h·cm^(−2)),corresponding to power density of 8732 W·kg^(−1).This method is applied to high voltage as well,152 mA·h·g^(−1)at 3.0–4.6 V and 20 C(0.99 mA·h·cm^(−2))was achieved with high-voltage LCO(HVLCO),corresponding to power density of 11,552 W·kg^(−1).The cycling stability is also enhanced,with the capacity retention maintaining more than 96%after 100 cycles at 0.1 *** the first time,UCNF is demonstrated to suppress the excessive decomposition of the electrolytes and solvents by blocking electron injection/extraction between LCO and electrolyte *** findings provide a simple method for improving LCO rate performance,especially at high C-rates.

关键词： lithium-ion batteries lithium cobalt oxides carbon nanomaterials side reactions

Latent ancestral graph of structure vector autoregressive models

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Journal of Systems Engineering and Electronics 2010年第2期21卷 233-238页

作者： Wei Gao1,2and Zheng Tian2,3 1.School of Statistics,xi’an University of Finance&Economics,xi’an 710061,P.R.china 2.Department of Applied Mathematics,Northwestern Polytechnical University,xi’an 710072,P.R.china 3.State Key Laboratory of Remote Sensing Science,Institute of Remote Sensing Applications,chinese academy of sciences,Beijing 100101,P.R.china School of Statistics Xi'an University of Finance & Economics Xi'an 710061 P. R. China Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 P. R. China Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 P. R. China State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 P. R. China

A class of latent ancestral graph for modelling the dependence structure of structural vector autoregressive （VAR） model affected by latent variables is proposed. The graphs are mixed graphs with possibly two kind of edges, namely directed and bidirected edges. The vertex set denotes random variables at dif- ferent times. In Gaussian case, the latent ancestral graph leads to a simple parameterization model. A modified iterative conditional fitting algorithm is presented to obtain maximum likelihood esti- mation of the parameters. Furthermore, a log-likelihood criterion is used to select the most appropriate models. Simulations are performed using illustrative examples and results are provided to demonstrate the validity of the methods.

关键词： multivariate time series latent ancestral graph itera- tive conditional fitting.

Optical results of the black hole microquasar SS 433

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 153-156页

作者： LI Hui1,2 & YAN JingZhi1,3 1 Purple Mountain Observatory,chinese academy of sciences,Nanjing 210008,china 2 Graduate University of chinese academy of sciences,Beijing 100049,china 3 service d’Astrophysique,CEA Saclay and University Paris Diderot,91191 Gif-sur-Yvette,France Purple Mountain Observatory Chinese Academy of Sciences Nanjing China Graduate University of chinese academy of sciences Beijing China service d’Astrophysique CEA Saclay and University Paris Diderot Gif-sur-Yvette France

We present optical spectroscopic observations of SS 433 during different precessional and orbital *** 2004,2007 and 2008 data provide us a good chance to study the variability of the Hα line at different orbital phases for nearly the same disk *** data show that the Hα of SS 433 usually had a symmetric profile between orbital phases 0.25-0.75,while an asymmetric structure with a strong red peak was observed for other orbital *** suggest that the orbital variability of Hα emission is connected with accretion flow from the donor star to the accretion *** addition,we attribute the dramatic increase of Hα emission during our 2007 observational run,which had a time scale of one day,to the emergence of strong jets.

关键词： high-mass X-ray binary black hole spectroscopy outflow wind relativistic jet

The exploration of satellite clock and ephemeris error correction in wide area differential system

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The exploration of satellite clock and ephemeris error corre...

第三届中国卫星导航学术年会

作者： ChengLin CAI 1* xiaoHui LI 2 &HaiTao WU 3 1.Guilin University of Electronic Technology,541004,Guilin,china 2.national time service center,chinese academy of sciences,710600,Lintong,china 3.academy of Opto-Electronics,chinese academy of sciences,100094,Beijing,china

Real time principle of wide area differential GPS(WADGPS)uses a generally inverted positioning method of four-dimensional solution of satellite clock and ephemeris *** with the real time single point positioning,positioning accuracy of this method is improved greatly,but the DOP of four-dimensional calculation is up to several hundred,under the error amplification effect of DOP,1 m positioning precision level of WADGPS is difficult to *** overcome the limit of DOP,the feasibility on large and small part decomposition of satellite clock and ephemeris error is analyzed, and optimal differential performances of the exploring two smallness correction methods:Small DOP and no DOP constraint,are analyzed,and they will be the foundation for further exploration.

关键词： wide area differential GPS(WADGPS) DOP satellite clock ephemeris

Effect of Mn Addition and Heat Treatment on the Corrosion Behaviour of Mg-Ag-Mn Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 665-677页

作者： You Lv Yupeng Zhang xi Liu Zehua Dong xiaorong Zhou xinxin Zhang Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China Hubei Engineering Research Centre for Biomaterials and Medical Protective Materials Huazhong University of Science and TechnologyWuhan430074China Corrosion and Protection Centre Department of MaterialsThe University of ManchesterManchesterM139PLUK

The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of Mg-Ag-Mn alloys is investigated with the underlying microstructural factors examined. The Mg-Ag alloy with 2 wt% Mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of Mn results in α-Mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-Mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.

关键词： Mg-Ag alloy Mn addition Post-casting heat treatment Cathodic activity Corrosion mechanism

Research on AutoNav-Guiding Technology for Airplane Taxiing

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Research on AutoNav-Guiding Technology for Airplane Taxiing

第三届中国卫星导航学术年会

作者： Wu Hai-tao1 2 Zou De-cai1 2 Han Tao1 2 Lu xiao-chun1 2 1.national time service center chinese academy of sciences xi’an 710600 china 2.Key Laboratory of Precision Navigation and Timing Technology chinese academy of sciences xi’an 710600 china

Aircraft taxiing on the ground can reach or leave from parking bay with the help of"FOLLOW ME"airport guide car,a process that requires a lot of manpower,material and financial *** the extensive use of Satellite-based navigation system and the rapid development of modern communication technology and automatic control technology,this paper presents and studies aircraft automatic guidance technology to replace the airport guide car during airplane *** basic idea is that,based on the landing PVT information provided by GNSS navigation equipment onboard the aircraft,control tower planes aircraft taxiing routes after landing automatically according to airport GIS data and the actual airport flight schedule,and sends to the aircraft crew through wireless communication *** crew will match the real-time aircraft GNSS positioning information to the taxiing route provided by control tower using finite element theory coordinates matching *** matching results will be shown on the cockpit Multi-Function Display（MFD）or on the Head-up Display of windshield glass with the flashing arrows to guide the pilot taxiing under the established ***-guiding technology occupies a certain advantage in the implementation complexity,cost,size and energy consumption compared to aircraft taxiing with the help of airport guide car,and auto-guiding technology can also be used for the machine automatic guidance in the other places.

关键词： AutoNav-Guiding taxiing route finite element coordinates matching

Sea-level change in coastal areas of china:Status in 2021

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Advances in Climate Change Research 2024年第3期15卷 515-524页

作者： Wen-Shan LI Hui WANG Wen-xi xiANG Ai-Mei WANG Wei-Qing XU Yu-xi JIANG xin-Hui WU Meng-Yuan QUAN national Marine Data and Information service Tianjin 300171China Ocean University of Chin1 Qingdao 266100China University of Michigan‒Shanghai Jiao Tong University Joint Institute Shanghai 200030China

The sea level in coastal areas of china reached the second highest in 2021,just after that recorded in *** force and dynamic analyses based on tide gauges,satellite observations,reanalysis data and regional numerical outputs were conducted to understand these abnormally high sea levels and determine their possible *** show that the coastal sea level of china had increased at an annual rate of 3.4±0.3 mm during 1980-2021,with an acceleration of 0.06±0.02 mm per *** superposition of significant oscillations of quasi-2,3-7,quasi-9,quasi-11,quasi-19 and 20-30 years contributed to the anomalously high sea *** negative-phased El Nino/Southern Oscillation was correlated with the anomalously high sea level and the north-south anti-phase pattern of the coastal sea level in ***,phase lags of 1-4 months occurred with the sea-level *** a decadal timescale,the Pacific Decadal Oscillation(PDO)was negatively correlated with the anomalous mean sea level(MSL),and the negative-phased PDO contributed to the anomalous sea-level change in ***,the monthly MSL peaked in April and July,and the contribution of wind stress to the anomalously high sea level was 38.5%in the south of the Taiwan Strait in April and 30%along the coast of china in *** results were consistent with the tide gauge and satellite *** agreement was also observed between the coastal sea-level fingerprint and the air and sea surface temperatures.

关键词： Sealevel La Nina PDO Wind stress