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Mid-infrared Period-Luminosity Relations of Gaia DR3 Long Period Variables

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Research in Astronomy and Astrophysics 2024年第7期24卷 56-70页

作者： Xiaohan chen Xiaodian chen Licai Deng Shu Wang tianlu chen Department of Physics College of ScienceTibet UniversityLhasa 850000China Key Laboratory of Cosmic Rays(Tibet University) Ministry of EducationLhasa 850000China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of the Chinese Academy of SciencesBeijing 100049China Department of Astronomy China West Normal UniversityNanchong 637009China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China

Long period variable(LPV)stars are very promising distance indicators in the infrared *** selected asymptotic giant branch(AGB)stars in the Large and Small Magellanic Cloud(LMC and SMC)from the Gaia Data Release 3 LPV catalog,and classified them into oxygen-rich(O-rich)and carbon-rich(C-rich)AGB *** the Wide-field Infrared Survey Explorer database,we determined the W1-and W2-band period-luminosity relations(PLRs)for each pulsation-mode sequence of AGB *** dispersion of the PLRs of O-rich AGB stars in sequences C'and C is relatively small,around 0.14 *** PLRs of LMC and SMC are consistent in each *** the W2 band,the PLR of large-amplitude C-rich AGB stars is steeper than that of small-amplitude C-rich AGB stars,due to their more circumstellar *** two methods,we find that some PLR sequences of O-rich AGB stars in the LMC are dependent on *** coefficients of the metallicity effect areβ=-0.533±0.213 mag dex~1andβ=-0.767±0.158 mag dex~1for sequence C in W1 and W2 bands,*** significance of the metallicity effect in W1 band for the four sequences is 2.2-3.5σ.Both of these imply that distance measurements using O-rich Mira may need to take the metallicity effect into account.

关键词： stars variables general-stars distances-infrared stars

Spatial Accessibility to Shopping Malls in Nanjing,China:Comparative Analysis with Multiple Transportation Modes

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Chinese Geographical Science 2020年第4期30卷 710-724页

作者： LI Ang chen Jie QIAN tianlu ZHANG Wenhan WANG Jiechen Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural ResourcesSchool of Geography and Ocean ScienceNanjing UniversityNanjing 210023China School of Architecture and Surveying Engineering Datong UniversityDatong 037009China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

This study attempts to evaluate the rationality of the spatial layout of shopping malls and identify the urban area with poor shopping mall accessibility,as well as to provide a reference and assist decision-making for *** the case of Nanjing,China,this study developed a method to evaluate the accessibility of shopping malls by three transport modes(car traffic,public transit,and bicycle).Specially,we divide the urban space into a regular hexagonal grid and harvest the total travel time from each of 7204 hexagon centroids to each of 129 shopping malls using the Baidu Internet *** door-to-door travel time approach is used to evaluate all travel stages(walking,waiting,transfer,and transportation)based on travel time *** further divide the shopping malls into two levels(super-regional and regional)based on the Dianping App’s information and develop the indicator of accessibility to shopping malls:the number of shopping malls within tolerance time thresholds and apply the closest facility and cumulative opportunities methods to measure accessibility *** results show that the accessibility estimations vary greatly with transport *** accessibility of shopping malls presents a concentric ring trend centered on the city center under the car traffic and bicycle *** public transit accessibility tends to axially extend due to the topology of bus routes and metro *** particular,we observe that the accessibility of shopping malls in Nanjing has an uneven spatial distribution pattern,with high accessibility values in the central urban areas and lots of underserved areas in urban fringe *** on the accessibility measurements,we finally map the poor accessibility area and propose corresponding implications for urban planning.

关键词： spatial accessibility shopping mall access transport mode door-to-door travel time internet maps

Effect of nano-CaO particle on the microstructure,mechanical properties and corrosion behavior of lean Mg-1Zn alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 794-814页

作者： Guangxin Shen Shaoyuan Lyu Leiting Yu tianlu Li chen You Xuewei Wang Minfang chen Bin Jiang School of Materials Science and Engineering Tianjin University of TechnologyTianjin 300384China Key Laboratory of Display Materials and Photoelectric Device(Ministry of Education) Tianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Function Materials Education Tianjin University of TechnologyTianjin 300384China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were *** results showed that the addition of nano-CaO significantly refined the grain size and improved mechanical properties of the Mg-1Zn *** the same time,CaO reacted with molten Mg in situ to form nano-MgO,whose corrosion product in SBF solution was the same with the degradation product of Mg matrix,resulting in the enhanced compactness of the Mg(OH)_(2) layer and reduced corrosion rate of *** Mg-1Zn alloy had lower corrosion resistance due to excessively large grain size and shedding of corrosion *** composite with 0.5 wt.%CaO had the best corrosion resistance with a weight loss of 9.875 mg·y^(-1)·mm^(-2)due to the small number of Ca_(2)Mg_(6)Zn_(3) phase and suitable grain *** for composites with high content of CaO(0.7 wt.%and 1.0 wt.%),they had lower corrosion resistance due to the coexistence of large number of Ca_(2)Mg_(6)Zn_(3) and Mg_(2)Ca at grain boundaries,especially for 1.0 wt.%CaO composite,resulting from the strong micro-galvanic corrosion.

关键词： Lean Mg alloy In situ MgO Nanoparticles Grain refinement Corrosion resistance

SARS-CoV-2 variants,immune escape,COVID-19 vaccine,and therapeutic strategies

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Science China(Life Sciences) 2023年第2期66卷 406-410页

作者： Haiying que Li chen Xiawei Wei Laboratory of Aging Research and Cancer Drug Target State Key Laboratory of Biotherapy and Cancer CenterNational Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengdu 610041China

The global pandemic of coronavirus disease 2019(COVID-19) caused by severe acute respiratory syndrome coronavirus2(SARS-CoV-2) has brought considerable challenges to worldwide public health and the economy. Over 535 m... 详细信息

关键词： acute respiratory vaccine

Microphysical Characteristics of Rainfall Based on Long-Term Observations with a 2DVD in Yangbajain,Tibet

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Advances in Atmospheric Sciences 2024年第9期41卷 1721-1734页

作者： Ming LI Yongheng BI Yonghai SHEN Yinan WANG Ciren Nima tianlu chen Daren LYU Key Laboratory for Cosmic Rays of the Ministry of Education Tibet UniversityLhasa 850000China Key Laboratory of Middle Atmosphere and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChinese Academy of ScienceBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Raindrop size distribution(DSD)plays a crucial role in enhancing the accuracy of radar quantitative precipitation estimates in the Tibetan Plateau(TP).However,there is a notable scarcity of long-term,high-resolution observations in this *** address this issue,long-term observations from a two-dimensional video disdrometer(2DVD)were leveraged to refine the radar and satellite-based algorithms for quantifying precipitation in the hinterland of the *** was observed that weak precipitation(Rquency precipitation radar in the TP is improved based on the statistical results of the DSD.

关键词： Tibetan Plateau raindrop size distribution 2DVD dual frequency radar microphysical features

Suppressing abnormal grain growth and switching precipitation behaviors in ZK60 Mg profile by inducing pre-tension

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Journal of Materials Science & Technology 2023年第24期155卷 89-101页

作者： Jianwei Tang Liang chen Zhigang Li Biaohua que Guoqun Zhao Cunsheng Zhang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China

The pre-tension was induced to suppress the abnormal grain growth(AGG)of ZK60 Mg profile during solution *** effects of pre-tension on the microstructure evolution and mechanical properties were studied,and the suppressing mechanism was *** the pre-tension strain was larger than 10%,AGG during solution could be effectively inhibited,resulting in a sharp decrease in the grain *** suppression effects were realized by restricting the orientation dependent of AGG and promoting static *** pre-tension reset the distributions of stored energy and sizes of the grains with〈11–20〉and〈10–10〉orientations,and thus retarded the orientation dependent of ***,the pre-tension introduced a mass of dislocations,twins,and stacking faults,all of which promoted the occurrence of static recrystallization,and the grain structure was further *** pre-tension accelerated the precipitation kinetics during aging,resulting in fine and dense *** the increase of pre-tension strain,the strength of ZK60 Mg profile monotonically increased.

关键词： Mg alloy Abnormal grain growth Pre-tension Microstructure Mechanical properties

Mesoporous H-ZSM-5 nanocrystals with programmable number of acid sites as ＂solid ligands＂ to activate Pd nanoparticles for C-C coupling reactions

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Nano Research 2018年第2期11卷 874-881页

作者： Wenyu Ke tianlu Cui Qiuying Yu Mengying Wang Libing Lv Honghui Wang Zhidong Jiang XinhHao Li Jiesheng chen School of Chemistry and Chemical Engineering Shanghai Jiao Tong University Shanghai China

In this work, we described a proof-of-concept method to promote the activity and selectivity of Pd nanoparticles for heterogeneous catalysis （exemplified by C-C coupling reactions） by using acid sites within a zeolite framework. The Pd nanoparticles were encapsulated inside the crystalline walls of mesoporous H-ZSM-5 leading to hybrid samples （denoted as Pd@mZ-x-H） with controlled number of acid sites. A linear relationship between the number of acid sites of the zeolite nanocrystals and the catalytic activities of the Pd nanoparticles in organic reactions was established. Moreover, the shape-dependent selectivity of Pd@mZ-x-H was not sacrificed when the final activity was enhanced.

关键词： Brgnsted acidity palladium HZSM-5 mesopores Suzuki coupling

Self-assembled TiO_(2)hole-blocking layers for efficient perovskite solar cells

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International Journal of Minerals,Metallurgy and Materials 2022年第6期29卷 1280-1285页

作者： Zhongbao que Liang Chu Shuaibo Zhai Yifei Feng chen chen Wei Liu Ruiyuan Hu Jing Hu Xing’ao Li New Energy Technology Engineering Laboratory of Jiangsu Province&School of Science&School of Materials Science and Engineering&School of Electronic and Optic Engineering Nanjing University of Posts and TelecommunicationsNanjing 210023China

The self-assembly process for compatible functional layers of devices is a simple,feasible,and energy-saving *** mesoporous perovskite solar cells(PSCs),compact and scaffold TiO_(2) films generally function as the hole-blocking and electron-transporting layers,***,both of these layers are usually generated through a high-temperature annealing ***,we deposited TiO_(2) compact films through a room-temperature self-assembly process as effective hole-blocking layers for *** thickness of TiO_(2) compact films can be easily controlled by the deposition *** the optimization of TiO_(2) compact films(80 nm),the power conversion efficiency(PCE)of mesoporous PSCs without and with hole conductor layers increases up to 10.66%and 17.95%,***,an all-low-temperature planar PSC with the self-assembled TiO_(2) layer exhibits a PCE of 16.41%.

关键词： perovskite solar cells titanium dioxide self-assembly power conversion efficiency

Numerical differentiation of noisy data with local optimum by data segmentation

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Journal of Systems Engineering and Electronics 2015年第4期26卷 868-876页

作者： Jianhua Zhang Xiufu que Wei chen Yuanhao Huang Lianqiao Yang Key Laboratory of Advanced Display and System Applications (Shanghai University) Ministry of Education School of Mechanical & Electronic Engineering and Automation Shanghai University

A new numerical differentiation method with local opti- mum by data segmentation is proposed. The segmentation of data is based on the second derivatives computed by a Fourier devel- opment method. A filtering process is used to achieve acceptable segmentation. Numerical results are presented by using the data segmentation method, compared with the regularization method. For further investigation, the proposed algorithm is applied to the resistance capacitance （RC） networks identification problem, and improvements of the result are obtained by using this algorithm.

关键词： numerical differentiation noisy data local optimum,data segmentation.