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A type of polarimetric parameter for evaluating the reliability of model-based decomposition result and its application

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International Journal of Digital Earth 2023年第1期16卷 2111-2128页

作者： Wentao Han Haiqiang Fu Jianjun Zhu qinghua xie School of Geosciences and Info-Physics Central South UniversityChangshaPeople’s Republic of China School of Geography and Information Engineering China University of Geosciences(Wuhan)WuhanPeople’s Republic of China

The reliability of the model-based decomposition result,which is seldom investigated,is a key factor in determining whether decomposition parameters can be effectively applied to polarimetric synthetic aperture radar(PolSAR)*** this paper,a type of polarimetric parameter for evaluating the reliability of model-based decomposition result is *** originates from the degree of correlation between the scattering *** main idea is whether the measured power can be assigned to the corresponding scattering *** more the measured power that can be allocated to the corresponding scattering model,the more reliable the decomposition *** C-band Radarsat-2,L-band UAVSAR,X-band TerraSAR-X,and L-band E-SAR PolSAR data are selected for *** results show that the type of polarimetric parameter can effectively represent the reliability of the decomposition *** reliabilities of surface and double-bounce scattering are high in the ocean and orthogonal buildings,*** oriented buildings,the reliability of the decomposition result is lower owing to the overestimation of volume *** forested areas,reliability is generally higher if volume scattering is not ***,the results show that the reliability of soil moisture retrieval is positively correlated with surface scattering reliability.

关键词： Model-based decomposition decomposition reliability model correlation soil moisture inversion PolSAR

Inversion of vegetation height from Pol In SAR using complex least squares adjustment method

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Science China Earth Sciences 2015年第6期58卷 1018-1031页

作者： FU HaiQiang WANG ChangCheng ZHU JianJun xie qinghua ZHAO Rong School of Geosciences and Info-physics Central South University

In this paper, we propose the novel method of complex least squares adjustment （CLSA） to invert vegetation height accurately using single-baseline polarimetric synthetic aperture radar interferometry （PollnSAR） data. CLSA basically estimates both volume-only coherence and ground phase directly without assuming that the ground-to-volume amplitude radio of a particular polarization channel （e.g., HV） is less than -10 dB, as in the three-stage method. In addition, CLSA can effectively limit errors in interferometric complex coherence, which may translate directly into erroneous ground-phase and volume-only coherence estimations. The proposed CLSA method is validated with BioSAR2008 P-band E-SAR and L-band SIR-C PollnSAR data. Its results are then compared with those of the traditional three-stage method and with external data. It implies that the CLSA method is much more robust than the three-stage method.

关键词： polarimetric SAR interferometry (PolInSAR) complex least squares adjustment random volume over ground (RVoG) vegetation height inversion truncated singular value decomposition (T-SVD)

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寿司中菌落总数检测的不确定度评定

中国卫生标准管理 2024年第8期15卷 17-20页

作者：谢清华吴小凤陈韵妍泉州市疾病预防控制中心微生物检验科福建泉州362000

目的分析20份市售寿司菌落总数检验结果测量不确定度的来源,计算A类不确定度、B类不确定度等,评定测量不确定度,确定其置信区间。方法选取2023年4—8月20份市售寿司进行分析。按照《测量不确定度评定与表示》要求,参照《食品安全国家标... 详细信息

目的分析20份市售寿司菌落总数检验结果测量不确定度的来源,计算A类不确定度、B类不确定度等,评定测量不确定度,确定其置信区间。方法选取2023年4—8月20份市售寿司进行分析。按照《测量不确定度评定与表示》要求,参照《食品安全国家标准食品微生物学检验菌落总数测定》以及相关统计学方法进行计算。结果A类不确定度为0.0445,B类不确定度为0.0147,合成标准不确定度为0.0469,扩展不确定度为0.0978。结论实验室在进行微生物培养时需要一个稳定的环境,这种环境能够有效地保障检验结果的准确性和精密度,食品菌落总数的不确定度评定是确保食品安全质量的重要手段。

关键词：不确定度细菌总数 A类不确定度 B类不确定度合成标准不确定度扩展不确定度

预喷与外部EGR对车用柴油机燃烧和排放的影响

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中国工程机械学报 2024年第4期22卷 506-511页

作者：尹钰屹李岳林张五龙陈侗谢清华长沙理工大学湖南省工程车辆安全性设计与可靠性技术重点实验室湖南长沙410114 长沙理工大学汽车与机械工程学院湖南长沙410114

以某四缸水冷车用柴油机为样机,应用GT-Power软件搭建车用柴油机仿真模型,通过改变预主喷间隔、预喷油量和废气再循环(EGR)开度,研究中等负荷及转速工况下,不同的预喷策略以及引入外部EGR后两者共同作用对车用柴油机燃烧和排放性能的影... 详细信息

以某四缸水冷车用柴油机为样机,应用GT-Power软件搭建车用柴油机仿真模型,通过改变预主喷间隔、预喷油量和废气再循环(EGR)开度,研究中等负荷及转速工况下,不同的预喷策略以及引入外部EGR后两者共同作用对车用柴油机燃烧和排放性能的影响。试验结果表明:随着预喷正时从-17°CA提前到-37°CA,预喷油量从3.3 mg增加到9.9 mg,燃烧特性、碳氢化合物(HC)和一氧化碳(CO)排放均得到有效改善,但燃油消耗率和NOx排放总体呈上升趋势。在预喷策略的基础上引入外部EGR后,随着EGR率从5%增加到25%,NOx排放保持在较低水平,但缸内燃烧变差,HC和CO排放增多。在1 800 r/min、50%负荷的试验工况下,较小的预喷油量、中等的预喷间隔以及中等的EGR开度更有利于车用柴油机的燃烧和排放。

关键词：柴油机预喷正时预喷油量废气再循环排放控制

Underlying topography and forest height estimation from SAR tomography based on a nonparametric spectrum estimation method with low sidelobes

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International Journal of Digital Earth 2022年第1期15卷 2184-2201页

作者： Youjun Wang Xing Peng qinghua xie Xinwu Li Xiaomin Luo Yanan Du Bing Zhang School of Geography and Information Engineering China University of Geosciences (Wuhan)WuhanPeople’s Republic of China Aerospace Information Research Institute Chinese Academy of SciencesBeijingPeople’s Republic of China School of Geographical Sciences Guangzhou UniversityGuangzhouPeople’s Republic of China School of Geomatics Liaoning Technical UniversityFuxinPeople’s Republic of China

The underlying topography and forest height play an indispensable role in many fields,including geomorphology,civil engineering construction,forest investigation,and the modeling of natural *** a new microwave remote sensing technology with three-dimensional imaging capability,synthetic aperture radar(SAR)tomography(TomoSAR)has already been proven to be an important tool for underlying topography and forest height *** spectrum estimation methods have now been proposed for ***,most of the commonly used methods are susceptible to noise and inevitably produce sidelobes,resulting in a reduced accuracy for the inversion of forest structural *** this paper,to solve this problem,a nonparametric spectrum estimation method with low sidelobes-the G-Pisarenko method-is *** method performs a logarithmic operation on the covariance matrix to obtain the main scattering characteristics of the objects of interest while suppressing the noise as much as *** effectiveness of the proposed method is demonstrated by the use of both simulated data and P-band airborne SAR data from a tropical forest region in Gabon,*** results show that the proposed method can reduce the sidelobes and improve the estimation accuracy for the underlying topography and forest height.

关键词： Underlying topography forest height TomoSAR G-Pisarenko method sidelobes

A Deep Learning-Enabled Skin-Inspired Pressure Sensor for Complicated Recognition Tasks with Ultralong Life

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Research 2024年第1期2023卷 443-454页

作者： Yingxi xie Xiaohua Wu Xiangbao Huang qinghua Liang Shiping Deng Zeji Wu Yunpeng Yao Longsheng Lu School of Mechanical&Automotive Engineering South China University of TechnologyGuangzhouChina

Flexible full-textile pressure sensor is able to integrate with clothing directly,which has drawn extensive attention from scholars *** the realization of flexible full-textile pressure sensor with high sensitivity,wide detection range,and long working life remains *** recognition tasks necessitate intricate sensor arrays that require extensive data processing and are susceptible to *** human skin is capable of interpreting tactile signals,such as sliding,by encoding pressure changes and performing complex perceptual *** by the skin,we have developed a simple dip-and-dry approach to fabricate a full-textile pressure sensor with signal transmission layers,protective layers,and sensing *** sensor achieves high sensitivity(2.16 kPa^(−1)),ultrawide detection range(0 to 155.485 kPa),impressive mechanical stability of 1 million loading/unloading cycles without fatigue,and low material *** signal transmission layers that collect local signals enable real-world complicated task recognition through one single *** developed an artificial Internet of Things system utilizing a single sensor,which successfully achieved high accuracy in 4 tasks,including handwriting digit recognition and human activity *** results demonstrate that skin-inspired full-textile sensor paves a promising route toward the development of electronic textiles with important potential in real-world applications,including human–machine interaction and human activity detection.

关键词： Deep Skin utilizing

Lignocellulose-Based Optical Biofilter with High Near-Infrared Transmittance via Lignin Capturing–Fusing Approach

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Research 2024年第3期2023卷 139-149页

作者： Shixu Yu Yifang Zhou Meixue Gan Lu Chen Yimin xie Yuning Zhong qinghua Feng Chaoji Chen Hubei Provincial Key Laboratory of Green Materials for Light Industry Hubei University of TechnologyWuhan 430068China.Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key LaboratorySchool of Resource and Environmental SciencesWuhan UniversityWuhan 430079China Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory School of Resource and Environmental SciencesWuhan UniversityWuhan 430079China Hubei Open University Wuhan 430074China.

Near-infrared (NIR) transparent optical filters show great promise in night vision and receiving windows. However, NIR optical filters are generally prepared by laborious, environmentally unfriendly processes that involve metal oxides or petroleum-based polymers. We propose a lignin capturing–fusing approach to manufacturing optical biofilters based on molecular collaboration between lignin and cellulose from waste agricultural biomass. In this process, lignin is captured via self-assembly in a cellulose network;then, the lignin is fused to fill gaps and hold the cellulose fibers tightly. The resulting optical biofilter featured a dense structure and smooth surface with NIR transmittance of ~90%, ultralow haze of close to 0%, strong ultraviolet-visible light blocking (~100% at 400 nm and 57.58% to 98.59% at 550 nm). Further, the optical biofilter has comprehensive stability, including water stability, solvent stability, thermal stability, and environmental stability. Because of its unique properties, the optical biofilter demonstrates potential applications in the NIR region, such as an NIR-transmitting window, NIR night vision, and privacy protection. These applications represent a promising route to produce NIR transparent optical filters starting from lignocellulose biomass waste.

关键词： transparent starting waste

Complex Least Squares Adjustment to Improve Tree Height Inversion Problem in PolInSAR

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Journal of Geodesy and Geoinformation Science 2019年第1期2卷 1-8页

作者： Jianjun ZHU qinghua xie Tingying ZUO Changcheng WANG Jian xie School of Geosciences and Info-Physics Central South UniversityChangsha 410083China

At present,the principal data processing methods involving complex observations are based on two strategies according to characteristics of the observation process,i.e.,step-by-step and direct ***,these strategies have some limitations,*** cannot consider statistical observation error information,redundant observations and so *** paper applies least squares methods to complex data processing to extend surveying adjustment theory from real to complex number *** compared the two adjustment criteria for a complex domain in a quantitative *** order to understand the effectiveness of complex least squares,tree height inversion from PolInSAR data is taken as an *** firstly established both a complex adjustment function model and a stochastic model for PolInSAR tree height inversion,and then applied the complex least squares method to estimate tree *** show that the complex least squares approach is reliable and outperforms other classic tree height retrieval methods;the method is simple and easy to implement.

关键词： surveying adjustment complex least squares polarimetric interferometric SAR (PolInSAR) tree height inversion three-stage algorithm

Evolution of the Mangrove Wetland since the Holocene: Current Progress and Future Perspectives

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Journal of Earth Science 2024年第5期35卷 1669-1678页

作者： Xueyan Yan Xianzhong Ke qinghua Li Yiqun Gan Xianjun xie Yamin Deng Geological Survey China University of Geosciences Wuhan Center China Geological Survey (Central South China Innovation Center for Geosciences) School of Environmental Studies China University of Geosciences

Mangrove wetlands are among the four most productive tropical and subtropical ecosystems. They are also a core component of the coastal blue carbon ecosystem, which is of great ecological significance to human beings, plants, animals, and the global carbon balance. There has been a global decrease in the distribution of mangrove forests, and their ecological function has gradually degenerated since the Holocene. Sediment from coastal mangrove wetlands can provide records of climate change and human activities, and multiple proxies including palynology, leaf fossil, biomarkers, DNA, phytolith and stable isotopes, can be used to reconstruct the evolutionary stages of paleo-mangroves and to identify the effect of natural processes and human activities on the distribution and evolution of mangroves. This information can provide theoretical support for mangrove protection and for improving carbon sequestration capacity. This paper summarizes and compares the multiple proxies for mangrove reconstruction, reviews progress in the study of natural succession of global mangroves since the Holocene, expands on the influence mechanisms of human activities on mangrove growth and development and uses past information to lay a foundation for a model to predict future mangrove development.

关键词： mangrove Holocene multiproxy sedimentary environment climate change environ-mental geology