检索结果-南通市图书馆

Empirical Line Method Using Spectrally Stable Targets to Calibrate IKONOS Imagery

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2008年第1期18卷 124-130页

作者： xu jun-feng Institute of Agricultural Remote Sensing and Information Technology Zhejiang University Hangzhou 310029 （China）.

By using speetrally stable targets, the empirical line （EL） method was tested to correct the multispectral IKONOS imagery acquired over Putuo Mountain, Zhejiang, China. A series of calibration targets, which were spectrally stable over time, were selected to establish the linear predicted equation. Subsequently, a series of spectrally stable validation targets were selected to assess the accuracy of the equations. And, validation targets, which were speetrally unstable over time, were used to test the feasibility of using the EL method to calibrate the archival remotely sensed data. Ground reflectance measurements for each target were made using an ASD FieldSpec spectroradiometer. A Trimble GeoXTTM GPS unit with sub-meter accuracy was used to estimate the target position accurately. Linear regression equations for four tKONOS bands were derived. The coefficients of determination for the blue, green, and red bands were all greater than 0.9800 and it was 0.9697 for the near infrared band. It was concluded that reasonable results could be obtained by using speetrally stable targets.

关键词： calibration empirical line method, IKONOS spectrally stable targets

Hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect neurons from cardiac arrest-induced pyroptosis

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第4期20卷 1103-1123页

作者： Xiahong Tang Nan Zheng Qingming Lin Yan You Zheng Gong Yangping Zhuang Jiali Wu Yu Wang Hanlin huang jun Ke feng Chen Shengli Clinical Medical College of Fujian Medical University Fujian Medical UniversityFuzhouFujian ProvinceChina Department of Emergency Fujian Provincial HospitalFuzhouFujian ProvinceChina Fujian Provincial Key Laboratory of Emergency Medicine FuzhouFujian ProvinceChina The Second Department of Intensive Care Unit Fujian Provincial Hospital South BranchFuzhouFujian ProvinceChina

Cardiac arrest can lead to severe neurological impairment as a result of inflammation,mitochondrial dysfunction,and post-cardiopulmonary resuscitation neurological *** preconditioning has been shown to improve migration and survival of bone marrow–derived mesenchymal stem cells and reduce pyroptosis after cardiac arrest,but the specific mechanisms by which hypoxia-preconditioned bone marrow–derived mesenchymal stem cells protect against brain injury after cardiac arrest are *** this end,we established an in vitro co-culture model of bone marrow–derived mesenchymal stem cells and oxygen–glucose deprived primary neurons and found that hypoxic preconditioning enhanced the protective effect of bone marrow stromal stem cells against neuronal pyroptosis,possibly through inhibition of the MAPK and nuclear factor κB ***,we transplanted hypoxia-preconditioned bone marrow–derived mesenchymal stem cells into the lateral ventricle after the return of spontaneous circulation in an 8-minute cardiac arrest rat model induced by *** results showed that hypoxia-preconditioned bone marrow–derived mesenchymal stem cells significantly reduced cardiac arrest–induced neuronal pyroptosis,oxidative stress,and mitochondrial damage,whereas knockdown of the liver isoform of phosphofructokinase in bone marrow–derived mesenchymal stem cells inhibited these *** conclude,hypoxia-preconditioned bone marrow–derived mesenchymal stem cells offer a promising therapeutic approach for neuronal injury following cardiac arrest,and their beneficial effects are potentially associated with increased expression of the liver isoform of phosphofructokinase following hypoxic preconditioning.

关键词： bone marrow–derived mesenchymal stem cells cardiac arrest cardiac resuscitation hypoxic preconditioning liver isoform of phosphofructokinase mitochondria neuroinflammation oxidative stress pyroptosis reactive oxygen species

Assessing the Response of Seasonal Variation of Net Primary Productivity to Climate Using Remote Sensing Data and Geographic Information System Techniques in Xinjiang

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2008年第12期50卷 1580-1588页

作者： Dai-Liang Peng jing-feng huang Cheng-Xia Cai Rui Deng jun-feng xu Institute of Agriculture Remote Sensing and Information System Application Zhejiang University Hangzhou 310029 China Xinjiang Institute of Meteorology Urumchi 830002 China

Net primary productivity （NPP） is a key component of energy and matter transformation in the terrestrial ecosystem, and the responses of NPP to global change locally and regionally have been one of the most important aspects in climatevegetation relationship studies. In order to isolate causal climatic factors, it is very important to assess the response of seasonal variation of NPP to climate. In this paper, NPP in Xinjiang was estimated by NOAA/AVHRR Normalized Difference Vegetation Index （NDVI） data and geographic information system （GIS） techniques. The impact of climatic factors （air temperature, precipitation and sunshine percentage） on seasonal variations of NPP was studied by time lag and serial correlation ageing analysis. The results showed that the NPP for different land cover types have a similar correlation with any one of the three climatic factors, and precipitation is the major climatic factor influencing the seasonal variation of NPP in Xinjiang. It was found that the positive correlation at 0lag appeared between NPP and precipitation and the serial correlation ageing was 0 d in most areas of Xinjiang, which indicated that the response of NPP to precipitation was immediate. However, NPP of different land cover types showed significant positive correlation at 2 month lag with air temperature, and the impact of which could persist 1 month as a whole. No correlation was found between NPP and sunshine percentage.

关键词： climate geographic information system techniques net primary productivity remote sensing seasonal variation serial correlation ageing time lag.

基于轻量化卷积神经网络的桥梁斜拉索PE护套损伤识别方法

在线全文

学校读者我要写书评

暂无评论

土木与环境工程学报（中英文） 2025年第1期47卷 167-178页

作者：刘啸宇黄永徐峰李惠上海交通大学船舶海洋与建筑工程学院上海200240 哈尔滨工业大学土木工程学院哈尔滨150090

深度神经网络和计算机视觉技术近年来在结构健康监测中发挥了越来越重要的作用。利用无人机航拍采集的桥梁斜拉索损伤图像数据,研究基于深度学习技术的斜拉索PE护套损伤识别方法。为实现在较低运算能力设备上对大跨度桥梁斜拉索表面局... 详细信息

深度神经网络和计算机视觉技术近年来在结构健康监测中发挥了越来越重要的作用。利用无人机航拍采集的桥梁斜拉索损伤图像数据,研究基于深度学习技术的斜拉索PE护套损伤识别方法。为实现在较低运算能力设备上对大跨度桥梁斜拉索表面局部损伤的智能快速识别,解决传统深度卷积神经网络的运算效率相对较低、模型参数规模较大的问题,提出轻量化处理的区域推荐型卷积神经网络模型。介绍区域推荐网络与其轻量化改进方法的理论基础,分析轻量化模型处理的必要性,其能在保证识别精度的前提下降低模型训练与预测的设备性能需求,达到节约计算资源与时间的目的;通过数据增广等多手段解决损伤样本数据量不足的问题,设置对比试验,统计分析结果,验证了轻量化神经网络模型的优越性。结果表明,轻量化网络在牺牲少量识别准确度的前提下,能够在较大程度上实现对模型复杂度与计算量的改进,在工程应用中能有效拓展神经网络的实用性。

关键词：桥梁斜拉索智能损伤识别轻量化神经网络计算机视觉深度学习

维普期刊数据库博看期刊

Experimental Investigation on an Absorption Heat Transformer for Production of Hot Water or Steam Generation

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2021年第2期30卷 574-584页

作者： LIU feng jing Yang LIU Taixiu SUI jun xu Yujie Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Shandong Urban and Rural Planning Design Institute Jinan 250013China

The absorption heat transformer is widely used to utilize low-temperature waste heat in the field of distributed energy,industrial processing,and long-distance indoor heating,because it can upgrade energy level and deliver heat to heated *** this work,an experimental system of a vertical single-stage LiBr/H2O absorption heat transformer was established to study its performance in the case of producing high-temperature water or low-pressure steam generation under different heating water flow *** useful output heat,coefficient of performance,exergy coefficient of performance,and gross temperature lift of the single-stage heat transformer have all been *** results show that the absorber cannot directly generate low-pressure steam under the condition of counter-flow heat exchange but can obtain more useful output *** largest useful output heat is 20.3 kW,which is higher than that in the case of parallel-flow heat *** generation of low-pressure steam has certain requirements on the mode of heat *** largest internal gross temperature lift of 28.1℃corresponds to the smallest coefficient of performance of 0.22 when the heating water flow rate is 2.1 m3/*** performance of the single-stage absorption heat transformer can be improved to some extent by increasing the heating water flow rate.

关键词： vertical falling film absorber counter flow and parallel flow high-temperature water low-pressure steam exergy coefficient of performance

Antibacterial property,corrosion and discoloration resistance of pure copper containing Zn or Ni

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2022年第12期41卷 4041-4046页

作者： Yun Jiang Wen-jing Zhang xu-jun Mi Guo-Jie huang Hao-feng Xie xue feng Li-jun Peng Zhen Yang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.LtdBeijing 100088China GRIMAT Engineering Institute Co. LtdBeijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China

This study focused on the effects of Zn and Ni addition on the antibacterial properties and corrosion resistance of copper *** antimicrobial properties of copper and copper alloys were evaluated using Escherichia coli... 详细信息

关键词： corrosion resistance alloys

Interface evolution of Cu-Ni-Si/Al-Mg-Si clad composite wires after annealing

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2020年第12期39卷 1419-1424页

作者： Zhen Yang xu-jun Mi xue feng Hao-feng Xie Li-jun Peng Guo-Jie huang Yan-feng Li Xiang-Qian Yin Key Laboratory of Nonferrous Metals and Processes GRIMAT Engineering Institute Co.LtdBeijing 101400China

Interface micros tructures of Cu-Ni-Si/Al-MgSi clad composite wires during isothermal annealing from 623 to 773 K were *** composite wires were fabricated by a drawing *** evolution of intermetallic compounds(IMCs)was analyzed.A continuous IMCs layer forms only after annealing for 1 min,which may be due to more IMCs nucleation points generated by deep drawing *** consist of Al_(4)Cu_(9),AlCu and Al_(2)Cu identified by energy-dispersive spectroscopy(EDS)and transmission electron microscopy(TEM).The growth activation energies of total IMCs,Al_(2)Cu,AlCu and Al_(4)Cu_(9),are 98.8,69.4,101.3 and 137.1 kJ·mol^(-1),*** higher growth activation energy of Al_(4)Cu_(9)results in the higher growth rate under high ***,the average interdiffusion coefficient for each IMC calculated by Wagner method shows that interdiffusion in Al_(2)Cu and AlCu is more active than that in Al_(4)Cu_(9).The higher growth rate of Al_(4)Cu_(9)may be caused by the long concentration range.

关键词： Intermetallic compounds Clad composite wires Diffusion Activation energy

Solid-state NMR for metal-containing zeolites:from active sites to reaction mechanism

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2020年第2期14卷 159-187页

作者： Xingling Zhao jun xu feng Deng National Center for Magnetic Resonance in Wuhan State Key Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsCAS Key Laboratory of Magnetic Resonance in Biological SystemsWuhan Institute of Physics and MathematicsInnovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Metal-containing zeolite catalysts have found a wide range of applications in heterogeneous *** understand the nature of metal active sites and the reaction mechanism over such catalysts is of great importance for the establishment of structure-activity *** advanced solid-state NMR(SSNMR)spectroscopy is robust in the study of zeolites and zeolite-catalyzed *** this review,we summarize recent developments and applications of SSNMR for exploring the structure and property of active sites in metal-containing ***,detailed information on host-guest interactions in the relevant zeolite catalysis obtained by SSNMR is also ***,we highlight the mechanistic understanding of catalytic reactions on metal-containing zeolites based on the observation of key surface species and active intermediates.

关键词： metal-containing zeolites solid-state NMR active site host-guest interaction reaction mechanism

Microstructural evolution and properties of a Cu-Cr-Ag alloy during continuous manufacturing process

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2021年第8期40卷 2213-2220页

作者： Gao-Lei xu Li-jun Peng Guo-Jie huang Hao-feng Xie Zhen Yang xue feng Xiang-Qian Yin xu-jun Mi State Key Laboratory of Nonferrous Metals and Processes GRIMAT Engineering Institute Co.Ltd.Beijing101417China Zhejiang Libo Industrial Co. Ltd.Shaoxing312050China

Microstructure evolution and properties of a Cu-Cr-Ag alloy during the continuous manufacturing process were investigated in detail by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)in the *** Cu-Cr-Ag alloy rod with uniform compositions is fabricated by upward continuous casting *** of the Cr phases are observed in the ascast *** the continuous extrusion process,the severe shear deformation and the dynamic aging *** average grain size of as-extruded alloy is much smaller than that of as-cast *** fcc and bcc Cr precipitates appear in the *** interaction mode between dislocations and precipitates can be identified as Orowan bypass mode according to the TEM *** overall difference in the yield strength between as-cast and as-extruded Cu-Cr-Ag alloy is attributed to solid solution strengthening,grain refinement strengthening,precipitation hardening and working hardening.

关键词： Cu-Cr-Ag alloy Upward continuous casting Continuous extrusion Microstructure Physical properties