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Stability of patches of oasis landscape in arid areas:A case study of Sangong River Watershed,xinjiang,China

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Chinese Science Bulletin 2006年第A1期51卷 92-100页

作者： LUO Geping ZHOU Chenghu CHEN xi xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Institute of Geographical Science and Resources Research Chinese Academy of Sciences Beijing 100101 China

绿洲的稳定性是在进化的过程和在干旱区域的绿洲的管理的关键科学问题之一。绿洲和它的表示的稳定性在不同规模也是不同的。这篇论文在 Tianshan 山的 Sangong 河分水岭与案例研究在风景补丁规模处理绿洲的稳定性。我们采用了 ther 激... 详细信息

绿洲的稳定性是在进化的过程和在干旱区域的绿洲的管理的关键科学问题之一。绿洲和它的表示的稳定性在不同规模也是不同的。这篇论文在 Tianshan 山的 Sangong 河分水岭与案例研究在风景补丁规模处理绿洲的稳定性。我们采用了 ther 激动地表达感情到进程 ther 的察觉到的、地理信息系统和数学统计方法激动地表达感情在 1978， 1987 和 1998 察觉到三个时期的图象，并且为在风景补丁规模代表绿洲稳定性提出途径。绿洲补丁的风景控制能力是动态风景变化的一种自然驱动力。在有它在它和另外的补丁之间的区域和形状复杂性和对比的风景变化增加以后的某个补丁类型的控制能力，和有它在它和另外的补丁之间的空间距离的还原剂。有最强壮的控制能力的补丁类型应该是风景的矩阵。绿洲风景补丁的变换源于自然、人为的驱动力，特别地人为的驱动力。变换比例越高，越多降低补丁类型的稳定性并且人为的骚乱越更强壮。有在在 1987 的 Sangong 河分水岭的最强壮的网控制能力的补丁类型是荒芜的草地，它是风景的矩阵；但是风景的矩阵在 1987 和 1998 被变成了灌溉陆地。绿洲风景进化上的风景补丁的控制能力逐渐地在程度也逐渐地减少了的 Sangong 河分水岭，和变化与时间减少了。这表明在风景补丁类型之中的相互作用通常通常趋于到还原剂，和绿洲风景补丁的自然稳定性趋于增加。然而，在风景补丁之中的变换由于集中的人的活动的增加更经常发生，它可能在绿洲风景引起环境资源补丁的更低的稳定性和介绍补丁的更高的稳定性。

关键词：稳定性景观保护绿洲 GIS 遥感 NDVI

Snow features on sea ice in the western Arctic Ocean during summer 2016

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International Journal of Digital Earth 2021年第10期14卷 1397-1410页

作者： Qing Ji xiaoping Pang xi Zhao Ruibo Lei Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhanPeople’s Republic of China Polar Research of China ShanghaiPeople’s Republic of China

Arctic sea ice and its snow cover are important components of the cryosphere and the climate system.A series of in situ snow measurements were conducted during the seventh Chinese Arctic expedition in summer 2016 in the western Arctic *** this study,we made an analysis of snow features on Arctic sea ice based on in situ observations and the satellite-derived parameter of snow grain size from MODIS spectral reflectance *** indicate that snow depth on Arctic sea ice varied between 19 and 241 mm,with a mean value of 100 *** mean density of the snow was 340.4 kg/m^(3)during the expedition,which was higher than that reported in previous *** measurements revealed that a depth hoar layer was widely developed in the snow,accounting for 30%∼50%of the total snow *** equivalent snow grain size was small on the surface and large at the bottom in snow *** average relative error between MODIS-derived snow grain size and in situ measured surface snow grain size is 14.6%,indicating that remote sensing is a promising method to obtain large-scale information of snow grain size on Arctic sea ice.

关键词： Snow cover snow grain size snow stratigraphy remote sensing

大孔柚子型微结构光纤探针的表面增强拉曼散射性能研究

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光谱学与光谱分析 2024年第2期44卷 527-533页

作者：李佳轩付子珍曹茜清胡志国付兴虎付广伟金娃毕卫红燕山大学信息科学与工程学院河北省特种光纤与光纤传感重点实验室河北秦皇岛066004

随着光纤制备工艺以及纳米材料制备技术的发展,光纤探针已成为一种新型的表面增强拉曼散射(SERS)基底,通过在普通单模光纤或多模光纤上制备不同的结构并修饰相应的纳米材料,可以得到多种类型的光纤表面增强拉曼散射探针,并实现较好的检... 详细信息

随着光纤制备工艺以及纳米材料制备技术的发展,光纤探针已成为一种新型的表面增强拉曼散射(SERS)基底,通过在普通单模光纤或多模光纤上制备不同的结构并修饰相应的纳米材料,可以得到多种类型的光纤表面增强拉曼散射探针,并实现较好的检测效果。但受限于光纤本身的结构,普通光纤仅能利用端面或侧表面提供拉曼检测的“热点”区域,限制了其SERS性能的进一步提高。因此制备了大孔柚子型微结构光纤(MSF)表面增强拉曼散射(SERS)探针,其中大孔柚子型MSF SERS探针结构通过一段阶跃多模光纤与柚子型微结构光纤熔接制得。实验分别对自制的纳米银溶胶基底以及大孔柚子型MSF SERS探针的SERS性能进行检测。采用溶胶自组装法制备负载银纳米颗粒的MSF SERS探针,通过控制自组装时间制备不同光纤SERS探针(Ag/MSF-x,其中x为自组装时间,分别为15、30、45、60 min)。采用溶液检测方法,利用Ag/MSF-x探针对10^(-3) mol·L^(-1)的亚甲基蓝(MB)探针分子进行检测,通过比较相同条件下的增强效果筛选得到Ag/MSF-45探针。为进一步检测Ag/MSF-45探针的SERS性能,制备不同浓度的MB溶液,分别利用纳米银溶胶基底和Ag/MSF-45探针对其进行检测。实验结果表明,纳米银溶胶基底对MB的检测限(LOD)为10^(-6) mol·L^(-1),Ag/MSF-45探针对MB的检测限(LOD)为10^(-7) mol·L^(-1);拉曼信号的再现性结果表明纳米银溶胶基底以及Ag/MSF-45探针在各个特征峰处的RSD值均在合理范围内;在1619 cm^(-1)拉曼位移处对纳米银溶胶基底以及Ag/MSF-45探针检测MB的拉曼强度和浓度进行对数转换拟合,纳米银溶胶基底的拟合优度R2达0.91628,Ag/MSF-45探针的拟合优度R2达0.98848;纳米银溶胶基底和Ag/MSF-45探针的再现性结果表明,其在各个特征峰处的RSD值均处于合理范围,但Ag/MSF-45探针的各特征峰RSD值均小于纳米银溶胶基底,最大为13.89%;利用10^(-6) mol·L^(-1)的MB对Ag/MSF-45探针的增强因子(AEF)进行计算,Ag/MSF-45探针的AEF达到6.09×10^(6),表现出良好的增强效果。因此,基于大孔柚子型MSF SERS探针凭借独特的空气孔结构使其具有较高的灵敏度以及良好的再现性,且其SERS性能均优于纳米银溶胶基底,在农业、化学分析、生物检测等领域及大分子物质检测等方面应用前景广泛。

关键词：表面增强拉曼散射柚子型微结构光纤光纤探针纳米银溶胶亚甲基蓝

A New Fusion Technique of remote sensing Images for Land Use/Cover

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Pedosphere 2004年第2期14卷 187-194页

作者： WULian-xi SUNBo ZHOUSheng-Lu HUANGShu-E ZHAOQi-Guo DepartmentofSurvey EastChinaInstituteofTechnology.Fuzhou344000（China）／E-mail：pkwlx@163com InstituteofSoilScience ChineseAcademyofSciencesNanjing210008（China） 3DepartmentofUrbanandResourcesSciences NanjingUniversityNanjing210093（China） MeteorologicalResearchInstituteofJiangxiProvince.-Nanchang330046（China）

In China, accelerating industrialization and urbanization followinghigh-speed economic development and population increases have greatly impacted land use/coverchanges, making it imperative to obtain accurate and up to date iufbimation on changes soas toevaluate their environmental effects. The major purpose of this study was to develop a new method tofuse lower spatial resolution multispectral satellite images with higher spatial resolutionpanchromatic ones to assist in land use/cover *** algorithm of a new fusion method known asedge enhancement intensity modulation (EEIM) was proposed to merge two optical image data sets ofdifferent spectral ranges. The results showed that the EEIM image was quite similar in color tolower resolution multispectral images, and the fused product was better able to preserve spectralinformation. Thus, compared to conventional approaches, the spectral distortion of the fused imageswas markedly reduced. Therefore, the EEIM fusion method could be utilized to fuse remote sensingdata from the same or different sensors, including TM images and SPOT5 panchromatic images,providing high quality land use/cover images.

关键词： EEIM fusion land cover land use remote sensing spectral preservation

一种用于土地利用调查的颜色保真的遥感图像融合方法

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土壤通报 2009年第4期40卷 731-735页

作者：吴连喜饶月辉江西省数字国土重点实验室杭州职业技术学院江西抚州344000

快速获取土地利用/土地覆盖信息是土地利用/土地覆盖变化研究的重要内容,RS是快速获取土地利用/土地覆盖现势信息的重要手段之一,由于不同类型的卫星传感器获取同一地区的遥感数据日益增多,常规的遥感图像融合方法如HSI变换法、Brovey... 详细信息

快速获取土地利用/土地覆盖信息是土地利用/土地覆盖变化研究的重要内容,RS是快速获取土地利用/土地覆盖现势信息的重要手段之一,由于不同类型的卫星传感器获取同一地区的遥感数据日益增多,常规的遥感图像融合方法如HSI变换法、Brovey变换法和PCA变换法进行融合时,存在不同程度的颜色失真现象,即融合后图像的色彩与多光谱图像存在较大差异,从而影响了地物的识别。分析了Brovey变换法存在颜色失真的原因,提出了一种低通比值融合法,该融合法首先对高几何分辨率的全色波段进行低能滤波,尔后将低分辨率多光谱图像与全色波段图像相乘,再除以滤波后的全色波段图像,便得到融合图像。从辐照的角度证明了该低通比值融合法具备理论基础,并从目视评价、定量分析、分类精度证实了该低通比值融合法优于Brovey变换法,该低通比值融合法是一种能较好地保全低分辨率多光谱图像颜色的融合方法。

关键词：融合颜色保真低通比值融合法

Participants Recruitment for Coverage Maximization by Mobility Predicting in Mobile Crowd sensing

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China Communications 2023年第8期20卷 163-176页

作者： Yuanni Liu xi Liu xin Li Mingxin Li Yi Li School of Communication and information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China School of Cyber Security and information Law Chongqing University of Posts and TelecommunicationsChongqing 400065China State key laboratory of Networking and Switching Beijing Research Institute China UnicomBeijing 100048China

Mobile Crowd sensing(MCS)is an emerging paradigm that leverages sensor-equipped smart devices to collect *** introduction of MCS also poses some challenges such as providing highquality data for upper layer MCS applications,which requires adequate ***,recruiting enough participants to provide the sensing data for free is hard for the MCS platform under a limited budget,which may lead to a low coverage ratio of sensing *** paper proposes a novel method to choose participants uniformly distributed in a specific sensing area based on the mobility patterns of mobile *** method consists of two steps:(1)A second-order Markov chain is used to predict the next positions of users,and select users whose next places are in the target sensing area to form a candidate pool.(2)The Average Entropy(DAE)is proposed to measure the distribution of *** participant maximizing the DAE value of a specific sensing area with different granular sub-areas is chosen to maximize the coverage ratio of the sensing *** results show that the proposed method can maximize the coverage ratio of a sensing area under different partition granularities.

关键词： data average entropy human mobility prediction markov chain mobile crowd sensing

Snow cover estimation from MODIS and Sentinel-1 SAR data using machine learning algorithms in the western part of the Tianshan Mountains

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Journal of Mountain Science 2020年第4期17卷 884-897页

作者： LIU Yang CHEN xi HAO Jian-Sheng LI Lan-hai State key laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Ili Station for Watershed Ecosystem Research Chinese Academy of SciencesXinyuan 835800China Research Center for Ecology and Environment of Central Asia Chinese Academy of SciencesUrumqi 830011China xinjiang Regional Center of Resources and Environmental Science Instrument Chinese Academy of SciencesUrumqi 830011China

Obtaining the spatial distribution of snow cover in mountainous areas using the optical image of remote sensing technology is difficult because of cloud and fog. In this study, the object-based principle component analysis–support vector machine(PCA–SVM) method is proposed for snow cover mapping through the integration of moderateresolution imaging spectroradiometer(MODIS) snow cover products and the Sentinel-1 synthetic aperture radar(SAR) scattering characteristics. First, derived from the Sentinel-1 A SAR images, the feature parameters, including VV/VH backscatter, scattering entropy, and scattering alpha, were used to describe the variations of snow and non-snow covers. Second, the optimum feature combinations of snow cover were formed from the feature parameters using the principle component analysis(PCA) algorithm. Finally, using the optimum feature combinations, a snow cover map with a 20 m spatial resolution was extracted by means of an object-based SVM classifier. This method was applied in the study area of the xinyuan County, which is located in the western part of the Tianshan Mountains in xinjiang, China. The accuracies in this method were analyzed according to the data observed at different experimental sites. Results showed that the snow cover pixels of the extraction were less than those in the actual situation(FB1=93.86, FB2=59.78). The evaluation of the threat score(TS), probability of detection(POD), and false alarm ratio(FAR) for the snow-covered pixels obtained from the two-stage SAR images were different(TS1=86.84, POD1=90.10, FAR1=4.01;TS2=56.40, POD2=57.62, FAR2=3.62). False and misclassifications of the snow cover and non-snow cover pixels were found. Although the classifications were not highly accurate, the approach showed potential for integrating different sources to retrieve the spatial distribution of snow covers during a stable period.

关键词： Snow cover Estimation Sentinel-1/2 MODIS Machine learning

Simulation and retrieval for spaceborne aerosol and cloud high spectral resolution lidar of China

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Science China Earth Sciences 2022年第3期65卷 570-583页

作者： Feiyue MAO xi LUO Jie SONG Zhenxin LIANG Wei GONG Weibiao CHEN School of remote sensing and information Engineering Wuhan UniversityWuhan 430079China State key laboratory of information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Electronic information School Wuhan UniversityWuhan 430079China key laboratory of Space Laser Communication and Detection Technology Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China

Clouds and aerosols can significantly affect global climate change and the atmospheric environment,and observing them three-dimensionally with high spatial and temporal resolutions is a long-standing *** lidars are effective instruments for the vertical detection of clouds and aerosols *** Mie scattering lidars were successfully launched and widely used,such as the Cloud-Aerosol Lidar with Orthogonal Polarization(CALIOP)and Geoscience Laser Altimeter ***,the retrieval of Mie scattering lidar data is an ill-posed problem that introduces a large *** spaceborne Aerosol and Cloud High Spectral Resolution Lidar(ACHSRL)of China is currently under development and scheduled for launch in the near *** ACHSRL attracted extensive attention,because it can separate Mie and Rayleigh scattering signals and avoid ill-posed *** this study,we conducted ACHSRL signal simulation and retrieval to explore the potential of the ***,we proposed a simplified scheme for retrieving optical parameters,which reduced the number of equations and intermediate variables of the traditional method and avoided false extrema in the backscatter coefficient ***,the experiments showed that the backscatter coefficient retrieval was overestimated owing to the influence of the Poisson noise but can be ***,we examined the feasibility of the strategy of“first retrieving the lidar ratio then retrieving the extinction coefficient”to improve the extinction coefficient *** found that the retrieval error in the simulated cases can be reduced to less than 1%of the original retrieval ***,we discussed the influence of the uncertainty of the iodine filter transmittance on the retrieval of the optical parameters and found that the average relative error was less than 1‰.Finally,we conducted simulation and retrieval based on the atmospheric parameters measured by the *** showed that

关键词： Atmospheric environment Laser detection Satellite Signal simulation Extinction coefficient Backscatter coefficient

Minimally invasive technology for continuous glucosemonitoring

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Bio-Design and Manufacturing 2022年第1期5卷 9-13页

作者： xinshuo Huang Jingbo Yang Shuang Huang Hui-jiuan Chen xi xie State key laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510006China Guangdong Provincial key laboratory of Sensor Technology and Biomedical Instrument School of Biomedical EngineeringShenzhen Campus of Sun Yat-Sen UniversityShenzhen 518107China

Introduction Despite the numerous breakthroughs made in medical and biomedical technologies,biosensing underneath the skin without any associated pain still sounds like a dream yet to be *** invasive biosensors refer to functional or electronic sensors that can contact the interior environment of living organisms and their biological tissues,while the connected bulk devices remain on the surface of the biological objects[1].Minimally invasive biosensors are currently a key research area because they can not only meet the increasing technical demands to precisely detect biological activities inside biological objects,but also provide an ideal platform to externally incorporate complicated functionalities and electronic integration[2].The current development level of minimally invasive sensing still necessitates solving the constraints and bottlenecks in the three aspects of functionalities,sensitivity and biocompatibility[3].In this perspective,we select minimally invasive sensors as a representative research object with the aim to solve the limitations of current diabetes diagnosis and treatment approaches.

关键词： breakthrough interior diagnosis