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Graphene oxide nanosheets coupled with paper microfluidics for enhanced on-site airborne trace metal detection

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Microsystems & Nanoengineering 2019年第1期5卷 643-654页

作者： Hao Sun Yuan Jia Hui dong Longxiang Fan School of Mechanical Engineering and Automation Fuzhou University350116 FuzhouChina Fujian Provincial Collaborative Innovation Center of High-End Equipment Manufacturing 350001 FuzhouChina School of Mechanical Engineering Southeast University210096 NanjingChina

Rapid on-site analysis of airborne trace metals has been heavily favored over traditional methodologies because air pollutants can be altered by environmental,behavioral,and social patterns at any given time and ***,existing portable approaches are either not capable of performing integrated on-site analysis or not yet practically *** graphene oxide(GO)in enhancing the analytical performance of paper-based colorimetric detection,for the first time,this paper reports the development of a practically useful portable system for accurate,sensitive on-site characterization of trace metals in ambient particulate matter(PM).The system consists of GOnanosheet-coated paper devices,unmanned aerial vehicle multiaxial sampling,and cellphone-based colorimetric *** increased specific surface area and the homogeneity of color distribution from the coating of GO improves the accuracy and sensitivity of the ***,by leveraging a Wi-Fi camera,a self-developed app and a sample pretreatment cartridge,metal in PM samples can be readily processed and characterized on-site within 30 *** effects of chip geometric design,pH,reaction volume,and metal interference on detection results have been *** detection limits of the system were calibrated to be 16.6,5.1,and 9.9 ng for metals Fe,Cu,and Ni,respectively,which are comparable to the detection limits of commercial inductively coupled plasma(ICP)instruments,thus making our portable system practically ***,the system was used for airborne trace-metal study at 6 locations in Fuzhou City(China),and the results obtained using our system demonstrated good agreement with those obtained by the *** significance of our system in supplementing air pollution study and furthering research on rapid,accurate,on-site air toxicity assessment was demonstrated.

关键词： coating metals trace

Functionalization of graphene materials by heteroatom-doping for energy conversion and storage

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Progress in Natural Science:Materials International 2018年第2期28卷 121-132页

作者： Chuangang Hu dong Liu Ying Xiao Liming Dai Center of Advanced Science and Engineering for Carbon (Case4carbon) Department of Macromolecular Science and Engineering Case Western Reserve University (CWRU) BUCT-CWRU International Joint Laboratories College of Energy Beijing University of Chemical Technology (BUCT) Center of Advanced Science and Engineering for Carbon (Case4carbon) Department of Macromolecular Science and Engineering Case Western Reserve University(CWRU)

Recent development in nanoscience and nanotechnology has opened up new frontiers in materials science and engineering to create new materials for energy generation and storage. Owing to their earth abundance, lowcost, structural tunability, large-surface area, and unique physicochemical properties, graphitic carbon materials have attracted a great deal of attention for energy-related applications. However, the pristine graphene materials without functionalization is intractable(insoluble and infusible), which has hindered their practical applications. Therefore, considerable research effort has been devoted to the development of functionalized graphene materials with desirable properties for specific applications, including energy conversion and storage. It was demonstrated that functionalized graphene materials with tunable work functions were useful as charge-extraction materials to effectively improve solar cell performance while those with high electrocatalytic activities could be used as metal-free catalysts in fuel cells, metal-air batteries, water splitting and integrated energy systems. This article provides a timely focused review on the development of heteroatom-doped graphene materials for low-cost, but efficient, energy generation and storage.

关键词： Heteroatom-doping Functionalization,Carbon-based catalysts Metal-free electrocatalysis,Energy conversion and storage

Weighted quantile regression for longitudinal data using empirical likelihood

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Science China Mathematics 2017年第1期60卷 147-164页

作者： YUAN XiaoHui LIN Nan dong XiaoGang LIU TianQing School of Basic Science Changchun University of Technology Department of Mathematics Washington University in St.Louis School of Mathematics Jilin University

This paper proposes a new weighted quantile regression model for longitudinal data with weights chosen by empirical likelihood(EL). This approach efficiently incorporates the information from the conditional quantile restrictions to account for within-subject correlations. The resulted estimate is computationally simple and has good performance under modest or high within-subject correlation. The efficiency gain is quantified theoretically and illustrated via simulation and a real data application.

关键词： empirical likelihood estimating equation influence function longitudinal data weighted quantile regression

Peat humification-and δ^(13)C_(cellulose)-recorded warm-season moisture variations during the past 500 years in the southern Altai Mountains within northern Xinjiang of China

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Journal of Mountain Science 2017年第11期14卷 2200-2211页

作者： ZHANG dong-liang YANG Yun-peng LAN Bo Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences University of Chinese Academy of Sciences School of Environmental and Chemical Engineering Chongqing Three Gorges University

To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns because the qualities of the retrieved proxy records and the spatial coverage of those records are not adequate. Northern Xinjiang of China is one of such areas where the records are not adequate. Here, we present a 500-yr land-surface moisture sequence from Heiyangpo Peat(48.34°N, 87.18°E, 1353 m a.s.l) in the southern Altai Mountains within northern Xinjiang. Specifically, peat carbon isotope value of cellulose(δ^(13)C_(cellulose)) was used to estimate the warm-season moisture variations and the degree of humification was used to constrain the δ^(13)C_(cellulose)-based hydrological interpretation. The climatic attributions of the interpreted hydrological variations were based on the warm-season temperature reconstructed from Belukha ice core and the warm-season precipitation inferred from the reconstructed Atlantic Multidecadal Oscillations(AMO). The results show that humification decreased and the δ^(13)C_(celluose)-suggested moisture decreased from ~1510 to ~1775 AD, implying that a constant dryingcondition may have inhibited peat decay. Our comparison with reconstructed climatic parameters suggests that the moisture-level decline was most likely resulted from a constant decline of precipitation. The results also show that humification kept a stable level and the δ^(13)C_(celluose)-suggested moisture also decreased from ~1775 to ~2013 AD, implying that peat decay in the acrotelm primarily did not depend on the water availability or an aerobic environment. Again, our comparison with reconstructed climatic parameters suggests that the land-surface moisturelevel decline was most likely resulted from a steady warming of growing-season temperature.

关键词： Peat Carbon isotope of cellulose Humification Warm-season moisture Southern Altai Mountains

BPR-UserRec:a personalized user recommendation method in social tagging systems

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The Journal of China Universities of Posts and Telecommunications 2013年第1期20卷 122-128页

作者： YANG Tan CUI Yi-dong JIN Yue-hui State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications

Social tagging is one of the most important characteristics of Web 2.0 services, and social tagging systems （STS） are becoming more and more popular for users to annotate, organize and share items on the Web. Moreover, online social network has been incorporated into social tagging systems. As more and more users tend to interact with real friends on the Web, personalized user recommendation service provided in social tagging systems is very appealing. In this paper, we propose a personalized user recommendation method, and our method handles not only the users＇ interest networks, but also the social network information. We empirically show that our method outperforms a state-of-the-art method on real dataset from *** dataset and Douban.

关键词： social tagging systems user recommendation tensor factorization

Experimental Research on Quantitative Inversion Models of Suspended Sediment Concentration Using Remote Sensing Technology

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Chinese Geographical Science 2007年第3期17卷 243-249页

作者： Wang Yanjiao Yan Feng Zhang Peiqun dong Wenjie Laboratory for Climate Studies of China Meteorological Administration National Climate Center Beijing 100081 China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China College of Resources Science & Technology Beijing Normal University Beijing 100875 China

Research on quantitative models of suspended sediment concentration （SSC） using remote sensing technology is very important to understand the scouting and siltation variation in harbors and water channels. Based onlaboratory study of the relationship between different suspended sediment concentrations and reflectance spectra measured synchronously, quantitative inversion models of SSC based on single factor, band ratio and sediment parameter were developed, which provides an effective method to retrieve the SSC from satellite images. Results show that the bl （430-500nm） and b3 （670-735nm） are the optimal wavelengths for the estimation of lower SSC and the b4 （780-835nm） is the optimal wavelength to estimate the higher SSC. Furthermore the band ratio B2/B3 can be used to simulate the variation of lower SSC better and the B4/B1 to estimate the higher SSC accurately. Also the inversion models developed by sediment parameters of higher and lower SSCs can get a relatively higher accuracy than the single factor and band ratio models.

关键词： suspended sediment concentration spectral reflectance inversion model

RESIDENTS' ATTITUDES TO TOURISM DEVELOPMENT IN ANCIENT VILLAGE RESORTS——Case Study of World Cultural Heritage of Xidi and Hong Villages

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Chinese Geographical Science 2004年第2期14卷 170-178页

作者： WANGLi TONGShi-rong LUSong YANGZhao WANGYong LIANGdong-dong CollegeofTourism AnhuiNormalUniversityWuhu241000P.R.China TourismBureauofMa＇anshanCity Ma＇anshan243000P.R.China

Tourism development surely has social, economic and environmental impacts on tourist *** study on resorts residents' attitudes can help understand the nature of tourism development and the extent to which it may influence on tourist destinations. By now, researches on residents' perception and attitudes are plenteous in the international circle and achievements are great, yet few are found in developing countries. As a most representative cultural tourist destination, World Cultural Heritage-Xidi and Hong villages in Yi County of Anhui Province, are drawing the attention of both tourists and academic circles. This article, taking Xidi and Hong villages as examples, seeks to analyze ancient village residents' attitudes towards tourism impacts and then tries further to explore the connection between tourism development and residents' attitudes. Both qualitative and quantitative surveys are applied in the exploratory investigation into local residents' attitudes of tourism impacts. Based on abundant face-to-face interviews with the local households, tourism enterprises concerned, local government and tourists from July to August of 2002, we are able to have a better understanding of local residents' attitudes to community life, and perception of tourism impacts on society, economy and environment. By this we can promote domestic study on resorts residents' attitudes, and provide some theoretical grounds for establishing tourism development planning and perfect community participation system at tourist destinations.

关键词： ancient village resort Xidi and Hong villages residents' attitudes

Convergence analysis and performance optimization of parallel concatenated systematic polar code

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The Journal of China Universities of Posts and Telecommunications 2018年第2期25卷 1-9页

作者： Liu Zhenzhen Niu Kai dong Chao Lin Jiaru School of Information and Communication Engineering Beijing University of Posts and Telecommunications

Similar to the analysis of Turbo codes, the parallel concatenated systematic polar code （PCSPC） can also be analyzed by the extrinsic information transfer （EXIT） chart. The convergence of the iterative decoding based on soft cancellation （SCAN） and belief propagation （BP） of PCSPC are analyzed by the EXIT chart. Analysis shows that SCAN decoder is more appropriate than BP decoder for this iterative decoding structure in terms of complexity. In addition, the weight coefficients of the iterative decoding structure are optimized by the simulated-EXIT （S- EXIT） chart, which improves the performance of PCSPC.

关键词： PCSPC EXIT chart SCAN decoder BP decoder weight coefficient

Three-dimensional meta-architecture with programmable mechanical properties

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International Journal of Smart and Nano Materials 2022年第1期13卷 152-165,I0009页

作者： Qiangqiang Zhang Jiaqi dong Yantang Zhao and Yueyan Zheng Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University) The Ministry of Education of ChinaLanzhou730000P.R.China College of Civil Engineering and Mechanics Lanzhou UniversityLanzhou730000P.R.China

Artificial metamaterials have attracted widespread attention of research communities due to their anomalous physical properties compared to those of conventional *** this study,we designed a three-dimensional(3D)lightweight metaarchitecture consisting of 6-connected anti-chiral *** mechanical properties(***’s modulus,compression strength,and Poisson’s ratio)of the proposed meta-architecture could be programmed by adjusting a series of geometric parameters,as shown through numerical ***,an optically sensitive polymer-based 3D meta-architecture with 6-connected anti-chiral features was constructed by the stereolithography *** to the regulation of the negative Poisson’s ratio,3D meta-architecture achieved a greater ductility under compression than those of traditional truss structures while retaining a relatively high strength and low *** experiments validated the excellent tunability of the mechanical properties of the proposed 3D 6-connected antichiral *** results suggest the promising applications of this structure in lightweight aircraft,vibration isolation,and mechanical sensors.

关键词： Artificial metamaterials anomalous physical properties anti-chiral features ductile compressibility tunability on mechanical properties