期刊文献+
共找到40,487篇文章
< 1 2 250 >
每页显示 20 50 100
A crosstalk-free dual-mode sweat sensing system for naked-eye sweat loss quantification via changes in structural reflectance 被引量:1
1
作者 Bowen Zhong Hao Xu +3 位作者 Xiaokun Qin Lingchen Liu Hailong Wang Lili Wang 《Bio-Design and Manufacturing》 SCIE EI CAS CSCD 2024年第4期428-438,共11页
Sweat loss monitoring is important for understanding the body’s thermoregulation and hydration status,as well as for comprehensive sweat analysis.Despite recent advances,developing a low-cost,scalable,and universal m... Sweat loss monitoring is important for understanding the body’s thermoregulation and hydration status,as well as for comprehensive sweat analysis.Despite recent advances,developing a low-cost,scalable,and universal method for the fabrication of colorimetric microfluidics designed for sweat loss monitoring remains challenging.In this study,we propose a novel laserengraved surface roughening strategy for various flexible substrates.This process permits the construction of microchannels that show distinct structural reflectance changes before and after sweat filling.By leveraging these unique optical properties,we have developed a fully laser-engraved microfluidic device for the quantification of naked-eye sweat loss.This sweat loss sensor is capable of a volume resolution of 0.5µL and a total volume capacity of 11µL,and can be customized to meet different performance requirements.Moreover,we report the development of a crosstalk-free dual-mode sweat microfluidic system that integrates an Ag/AgCl chloride sensor and a matching wireless measurement flexible printed circuit board.This integrated system enables the real-time monitoring of colorimetric sweat loss signals and potential ion concentration signals without crosstalk.Finally,we demonstrate the potential practical use of this microfluidic sweat loss sensor and its integrated system for sports medicine via on-body studies. 展开更多
关键词 Sweat loss sensor Microfluidic design Structural reflectance Dual-mode integration Crosstalk-free
下载PDF
Quantifying the chemical composition of weathering products of Hainan basalts with reflectance spectroscopy and its implications for Mars
2
作者 Xing Wu JiaCheng Liu +5 位作者 WeiChao Sun Yang Liu Joseph Michalski Wei Tan XiaoRong Qin YongLiao Zou 《Earth and Planetary Physics》 EI CAS CSCD 2024年第6期854-867,共14页
With the development of the hyperspectral remote sensing technique,extensive chemical weathering profiles have been identified on Mars.These weathering sequences,formed through precipitation-driven leaching processes,... With the development of the hyperspectral remote sensing technique,extensive chemical weathering profiles have been identified on Mars.These weathering sequences,formed through precipitation-driven leaching processes,can reflect the paleoenvironments and paleoclimates during pedogenic processes.The specific composition and stratigraphic profiles mirror the mineralogical and chemical trends observed in weathered basalts on Hainan Island in south China.In this study,we investigated the laboratory reflectance spectra of a 53-m-long drilling core of a thick basaltic weathering profile collected from Hainan Island.We established a quantitative spectral model by combining the genetic algorithm and partial least squares regression(GA-PLSR)to predict the chemical properties(SiO2,Al2O3,Fe2O3)and index of laterization(IOL).The entire sample set was divided into a calibration set of 25 samples and a validation set of 12 samples.Specifically,the GA was used to select the spectral subsets for each composition,which were then input into the PLSR model to derive the chemical concentration.The coefficient of determination(R2)values on the validation set for SiO2,Al2O3,Fe2O3,and the IOL were greater than 0.9.In addition,the effects of various spectral preprocessing techniques on the model accuracy were evaluated.We found that the spectral derivative treatment boosted the prediction accuracy of the GA-PLSR model.The improvement achieved with the second derivative was more pronounced than when using the first derivative.The quantitative model developed in this work has the potential to estimate the contents of similar weathering basalt products,and thus infer the degree of alteration and provide insights into paleoclimatic conditions.Moreover,the informative bands selected by the GA can serve as a guideline for designing spectral channels for the next generation of spectrometers. 展开更多
关键词 reflectance spectroscopy weathered basalts terrestrial analog quantitative retrieval MARS
下载PDF
Construction of universal quantitative models for the determination of cefoperazone sodium/sulbactam sodium for injection from different manufacturers using near-infrared reflectance spectroscopy 被引量:4
3
作者 逄焕欢 冯艳春 +1 位作者 张学博 胡昌勤 《Journal of Chinese Pharmaceutical Sciences》 CAS 2008年第1期22-29,共8页
To develop near-infrared (NIR) reflectance spectroscopic methods for the quantitative analysis of cefoperazone sodium/ sulbactam sodium from different manufacturers for injection powder medicaments. Various powders ... To develop near-infrared (NIR) reflectance spectroscopic methods for the quantitative analysis of cefoperazone sodium/ sulbactam sodium from different manufacturers for injection powder medicaments. Various powders of cefoperazone sodium/ sulbactam sodium were directly analyzed by non-destructive NIR reflectance spectroscopy using the spectrometer EQUINOX55. Two quantitative methods via integrating sphere (IS) and fiberoptic probe (FOP) models were explored from 6 batches of commercial samples and 42 batches of laboratory samples at a content ranging from 30% to 70% for cefoperazone and 60% to 20% for sulbactam. The root mean square errors of cross validation (RMSECV) and the root mean square errors of prediction (RMSEP) of IS were 1.79% and 2.85%, respectively, for cefoperazone sodium, and were 1.86% and 3.08%, respectively, for sulbactam sodium; and those of FOP were 2.93% and 2.92%, respectively, for cefoperazone sodium, and were 2.23% and 3.01%, respectively, for sulbactam sodium. Based on the ICH guidelines and Ref. 12, the quantitative models were then evaluated in terms of specificity, linearity, accuracy, precision, robustness and model transferability. The non-destructive quantitative NIR methods used in this study are applicable for rapid analysis of injectable powdered drugs from different manufacturers. 展开更多
关键词 NIR diffuse reflectance spectroscopy Non-destructive determination Cefoperazone sodium/sulbactam sodium Injection powder medicament Validation Counterfeit medicine
下载PDF
Quantitative Relationship between Leaf Area Index and Canopy Reflectance Spectra of Rice under Different Nitrogen Levels 被引量:1
4
作者 刘桃菊 徐涛 +3 位作者 姚静 张笑东 江绍琳 唐建军 《Agricultural Science & Technology》 CAS 2016年第11期2446-2448,2451,共4页
Monitoring rice growth by spectral remote sensing technology can provide scientific basis for the high yield and efficient production of rice. Field experiments with different nitrogen application amounts using Tianyo... Monitoring rice growth by spectral remote sensing technology can provide scientific basis for the high yield and efficient production of rice. Field experiments with different nitrogen application amounts using Tianyouhuazhan rice as test sam- ples were set up to study the relationship between rice leaf area index (LAI) and canopy reflectance spectral. The results showed that: the LAI increased with the amount of applied nitrogen; the canopy reflectance spectral showed significant re- sponse characteristics to groups with different nitrogen application levels; the corre- lation coefficient of LAI and canopy spectral reflectance reached the maximum at 720 nm red edge region. The mathematical model was constructed to predict the LAI according to the canopy reflectance spectra of rice. 展开更多
关键词 RICE Leaf area index Canopy reflectance spectra Mathematical model
下载PDF
Preparation of Cr_2O_3-based pigments with high NIR reflectance via thermal decomposition of CrOOH 被引量:8
5
作者 梁书婷 张红玲 +4 位作者 雒敏婷 刘红霞 白玉兰 徐红彬 张懿 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第8期2646-2652,共7页
In order to reduce greenhouse gas emission and urban heat island mitigation, pure and titanium(Ti)-doped Cr2O3 cool pigments were prepared via the thermal decomposition of CrOOH. The result reveals that the pure Cr2... In order to reduce greenhouse gas emission and urban heat island mitigation, pure and titanium(Ti)-doped Cr2O3 cool pigments were prepared via the thermal decomposition of CrOOH. The result reveals that the pure Cr2O3 pigment presents both a high near-infrared reflectance and excellent yellowish-green color. Meanwhile, titanium was doped to improve the NIR reflectance and strengthen the color. The color of the designed pigments was brighter, and most importantly, the NIR reflectance increased from 84.04% to 91.25% with increasing Ti content from 0 to 0.006% (mole fraction). However, excessive doping of Ti4+ for Cr3+ in Cr2O3 (x(Ti)≥0.008%) decreased the NIR reflectance. One possible reason is that the conductivity type of the Cr2?xTixO3+δ changed from p-type conduction to n-type conduction with increasing Ti content, accompanied by the change of the electrical resistivity and the NIR reflectance. The prepared yellowish-green Cr2O3 pigments have a great potential for extensive applications in construction and military. 展开更多
关键词 CrOOH CrOOH cool pigments NIR reflectance
下载PDF
Classification of Guizhou Aspidistra Plants by Near-infrared Diffuse Reflectance Spectroscopy 被引量:1
6
作者 高永跃 何顺志 徐文芬 《Agricultural Science & Technology》 CAS 2017年第4期575-578,590,共5页
[Objective] This study was conducted to establish a near-infrared diffuse reflectance spectroscopy of Guizhou Aspidistra plants. [Method] Twenty three batch- es of Guizhou Aspidistra plants including A. chishuiensis, ... [Objective] This study was conducted to establish a near-infrared diffuse reflectance spectroscopy of Guizhou Aspidistra plants. [Method] Twenty three batch- es of Guizhou Aspidistra plants including A. chishuiensis, A. spinula, A. Caespitosa, A. sichuanensis, A. ebianensis, A. retusa, A. guizhouensis and A. liboensis were subjected to drying, pulverization and sieving and then directly determined for near- infrared reflectance spectrums; and the plants in this genus were classified by clus- ter analysis and principal component analysis (PCA). [Result] The near-infrared re- flectance spectrums of the 23 batches of Guizhou Aspidistra plants showed very high similarity. The spectrums were processed by first derivative method, and the spectral range of 4 000-7 500 cm-1 was selected as the analytical range. Cluster analysis and PCA were employed to mass spectrum variables of plants in Aspidis- tra, fewer new variables became the linear combination of primary variables, and small differences between different varieties were enlarged, thereby facilitating intu- itive classification of plants in this genus. [Conclusion] Near-infrared diffuse re- flectance spectroscopy is nondestructive and rapid for determination of solid sam- pies, and provides a new method for the classification of Guizhou Aspidistra plants combined by information processing techniques. 展开更多
关键词 Guizhou Aspidistra plants Near-infrared diffuse reflectance spectroscopy CLASSIFICATION
下载PDF
Monitoring Protein and Starch Accumulation in Wheat Grains with Leaf SPAD and Canopy Spectral Reflectance 被引量:6
7
作者 TIAN Yong-chao, ZHU yan, CAO Wei-xing, FAN Xue-mei and LIU Xiao-jun(Key Laboratory of Crop Growth Regulation, Ministry of Agriculture/Nanjing Agricultural University,Nanjing 210095, P.R.China) 《Agricultural Sciences in China》 CAS CSCD 2003年第11期1205-1211,共7页
The research was conducted to determine the relationships of protein and starch accumulation dynamics in grains of wheat to post-heading leaf SPAD values and canopy spectral reflectance. The results showed that leaf n... The research was conducted to determine the relationships of protein and starch accumulation dynamics in grains of wheat to post-heading leaf SPAD values and canopy spectral reflectance. The results showed that leaf nitrogen accumulation was exponentially related to leaf SPAD values and linearly related to canopy spectral reflectance, and that there was negative linear relationship between leaf nitrogen accumulation and grain protein accumulation, but positive linear relationship between post-heading leaf nitrogen transloca-tion and grain protein accumulation at maturity. In addition, leaf SPAD values were parabolically related with and ratio indices R(l 500,610)and R(l 220,560)were exponentially related with protein and starch accumulation in grains. These results indicate that leaf SPAD values and canopy spectral reflectance should be good indicators of quality formation dynamics in wheat grains. 展开更多
关键词 WHEAT SPAD Spectral reflectance Ratio index Grain quality
下载PDF
The Study of Using Near-infrared Diffuse Reflectance Spectroscopy Rapid Identify Wheat Drought Resistance-Ⅱ 被引量:2
8
作者 吴少辉 冯伟森 +5 位作者 谷运红 焦珍 张学品 杨洪强 王卫东 张灿军 《Agricultural Science & Technology》 CAS 2013年第10期1507-1512,共6页
[Objective] The aim was to build an evaluation method rapidly identifying wheat drought tolerance with near infrared diffuse reflectance spectroscopy. [Method] In the research, 36 wheat varieties in 2007-2009 were cho... [Objective] The aim was to build an evaluation method rapidly identifying wheat drought tolerance with near infrared diffuse reflectance spectroscopy. [Method] In the research, 36 wheat varieties in 2007-2009 were chosen and drought-tolerance degrees of wheat were graded and identified according to Winter-wheat Drought Tol- erance Evaluation Technical Standards (GB/T 21127-2007), and harvest wheat grains underwent spectrum collection, with a full-spectrum analyzer, to establish a database. [Result] Based on qualitative analysis and full-spectrum correlation research, the coef- ficient of determination (RSQ) and cross-validation coefficient of determination (1-VR) were concluded at 0.697 5 and 0.600 2, showing near-infrared diffuse reflectance spectroscopy is of significant differences among wheat varieties and of significant or extremely significant correlation with drought-tolerance indices. [Conclusion] The re- search indicates that to evaluate drought-tolerance of wheat with near-infrared diffuse reflectance spectroscopy is a rapid and feasible way, which is simple, convenient without damages on grains, and of practical values for construction wheat drought-tol- erance evaluation index system and identification of breeding materials. 展开更多
关键词 Near infrared diffuse reflectance spectroscopy of wheat drought resis- tance screening index
下载PDF
A Method for Spaceborne Synthetic Remote Sensing of Atmospheric Aerosol Optical Depth and Vegetation Reflectance 被引量:6
9
作者 邱金桓 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1998年第1期18-31,共14页
Spaceborne synthetic remote sensing of atmospheric aerosol optical depth and vegetation reflectance is very significant, but it remains to be a question unresolved yet. Based on the property of vegetation reflectance ... Spaceborne synthetic remote sensing of atmospheric aerosol optical depth and vegetation reflectance is very significant, but it remains to be a question unresolved yet. Based on the property of vegetation reflectance spectra from near ultra violet to near infrared and the sensitivity of outgoing radiance to vegetation reflectance and atmospheric aerosol optical depth, a new method for spaceborne synthetic remote sensing of the reflectance and the depth is proposed, and an iteration correlation inversion algorithm is developed in this paper. According to numerical experiment, effects of radiance error, error in aerosol imaginary index and vegetation medium inhomogeneity on retrieved result are analyzed. Inversion results show that the effect of error in aerosol imaginary index is very important. As the error of aerosol imaginary index is within 0.01, standard errors of aerosol optical depth and vegetation reflectance solutions for 14 spectral channels from 410 nm to 900 nm are respectively less than 0.063 and 0.023. And as the radiance error is within 2%, the standard errors are less than 0.023 and 0.0056. 展开更多
关键词 Vegetation reflectance Aerosol optical depth Spaceborne remote sensing Sky radiance
下载PDF
The Statistical Prediction of the Vitrinite Reflectance and Study of the Ancient Geothermal Field in Songliao Basin,China 被引量:6
10
作者 Wu Chonglong Li Sitian Chen ShoutianChina University of Geosciences , Wuhan 430074 《Journal of Earth Science》 SCIE CAS CSCD 1991年第1期94-104,共11页
The resource of the gas from coal and coal measures deep in Songliao Basin has been drawing more and more attention to . It is necessary to find out the evolution regularity of the geothermal field of the basin in add... The resource of the gas from coal and coal measures deep in Songliao Basin has been drawing more and more attention to . It is necessary to find out the evolution regularity of the geothermal field of the basin in addition to a series of geological studies in order to predict its resources because the ancient geothermal field of the basin is one of the main factors controlling the generation , evolution and disappearance of oil and gas . In the recent twenty years , it is generally believed that vitrinite reflectance is the best quantitative marker for the ancient geothermal field . In the present paper , a systematic study of the vitrinite reflectance value of Songliao Basin and its influence factors is made by multiple statistical analysis so as to reconstruct the evolutional process of the Moho and the corresponding geothermal field . Then , an overall prediction is made of the vitrinite reflectance and the distribution of J3-K1 fault basin group at the bottom of Songliao Basin , which provides the evidence for the further prediction of the gas potentiality from coal and coal measures deep in the basin . 展开更多
关键词 statistical prediction vitrinite reflectance ancient geothermal field Moho evolution process Songliao Basin .
下载PDF
Derivation of salt content in salinized soil from hyperspectral reflectance data: A case study at Minqin Oasis, Northwest China 被引量:4
11
作者 QIAN Tana Atsushi TSUNEKAWA +3 位作者 PENG Fei Tsugiyuki MASUNAGA WANG Tao LI Rui 《Journal of Arid Land》 SCIE CSCD 2019年第1期111-122,共12页
Soil salinization is a serious ecological and environmental problem because it adversely affects sustainable development worldwide, especially in arid and semi-arid regions. It is crucial and urgent that advanced tech... Soil salinization is a serious ecological and environmental problem because it adversely affects sustainable development worldwide, especially in arid and semi-arid regions. It is crucial and urgent that advanced technologies are used to efficiently and accurately assess the status of salinization processes. Case studies to determine the relations between particular types of salinization and their spectral reflectances are essential because of the distinctive characteristics of the reflectance spectra of particular salts. During April 2015 we collected surface soil samples(0–10 cm depth) at 64 field sites in the downstream area of Minqin Oasis in Northwest China, an area that is undergoing serious salinization. We developed a linear model for determination of salt content in soil from hyperspectral data as follows. First, we undertook chemical analysis of the soil samples to determine their soluble salt contents. We then measured the reflectance spectra of the soil samples, which we post-processed using a continuum-removed reflectance algorithm to enhance the absorption features and better discriminate subtle differences in spectral features. We applied a normalized difference salinity index to the continuum-removed hyperspectral data to obtain all possible waveband pairs. Correlation of the indices obtained for all of the waveband pairs with the wavebands corresponding to measured soil salinities showed that two wavebands centred at wavelengths of 1358 and 2382 nm had the highest sensitivity to salinity. We then applied the linear regression modelling to the data from half of the soil samples to develop a soil salinity index for the relationships between wavebands and laboratory measured soluble salt content. We used the hyperspectral data from the remaining samples to validate the model. The salt content in soil from Minqin Oasis were well produced by the model. Our results indicate that wavelengths at 1358 and 2382 nm are the optimal wavebands for monitoring the concentrations of chlorine and sulphate compounds, the predominant salts at Minqin Oasis. Our modelling provides a reference for future case studies on the use of hyperspectral data for predictive quantitative estimation of salt content in soils in arid regions. Further research is warranted on the application of this method to remotely sensed hyperspectral data to investigate its potential use for large-scale mapping of the extent and severity of soil salinity. 展开更多
关键词 SALINITY index soil salt content spectral reflectance waveband PAIRS ARID regions
下载PDF
Graptolite, Chitinozoan and Scolecodont Reflectances and Their Use as Indicators of Thermal Maturity 被引量:2
12
作者 Andreas Hoffknecht Rainer Bainer Brocke Bernd-D. Erdtmann 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1993年第1期93-105,125-126,共15页
Based on studies of the reflectance of Ordovician and Silurian zooclasts from 11 sections around the Huangling Anticline, Hubei, China, combined with determination of the conodont colour alteration indices (CAI) and o... Based on studies of the reflectance of Ordovician and Silurian zooclasts from 11 sections around the Huangling Anticline, Hubei, China, combined with determination of the conodont colour alteration indices (CAI) and of infrared spectroscopy of dispersed organic matter from the same or adjacent horizons, it is further proved that reflectances of graptolites, chitinozoans and scolecldonts, like vitrinite and natural bitumen, increase with increasing maturation, but follow different reflectance paths. They may be used, therefore, as thermal maturation indicators. Graptolites display optically strong anisotropy. The maximum reflectance measured from graptolite on polished section cut parallel to the bedding plane is the most suitable for determination of maturation of their host rocks. In polished section chitinozoan and scolecodont show reflectance, but no bireflectance owing to their isotropy. The random reflectance of chitinozoans is higher than that of scolecodonts in the case of the same maturity. By analysing the distribution trends of graptolite, chitionzoan and scolecodont reflectances, the Ordovician and Silurian strata can be subdivided into three areas of maturation in the present region. The potential of oil or gas generation is discussed for each area. The result is basically coincident with the distribution pattern of regional organic maturation presented by CAI and infrared spectroscopic determination of organic matter. 展开更多
关键词 GRAPTOLITE CHITINOZOAN scolecodont reflectance
下载PDF
Characterizing and Estimating Fungal Disease Severity of Rice Brown Spot with Hyperspectral Reflectance Data 被引量:3
13
作者 LIU Zhan-yu HUANG Jing-feng TAO Rong-xiang 《Rice science》 SCIE 2008年第3期232-242,共11页
Large-scale farming of agriculture crops requires real-time detection of disease for field pest management. Hyperspectral remote sensing data generally have high spectral resolution, which could be very useful for det... Large-scale farming of agriculture crops requires real-time detection of disease for field pest management. Hyperspectral remote sensing data generally have high spectral resolution, which could be very useful for detecting disease stress in green vegetation at the leaf and canopy levels. In this study, hyperspectral reflectances of rice in the laboratory and field were measured to characterize the spectral regions and wavebands, which were the most sensitive to rice brown spot infected by Bipolaris oryzae (Helminthosporium oryzae Breda. de Hann). Leaf reflectance increased at the ranges of 450 to 500 nm and 630 to 680 nm with the increasing percentage of infected leaf surface, and decreased at the ranges of 520 to 580 nm, 760 to 790 nm, 1550 to 1750 nm, and 2080 to 2350 nm with the increasing percentage of infected leaf surface respectively. The sensitivity analysis and derivative technique were used to select the sensitive wavebands for the detection of rice brown spot infected by B. oryzae. Ratios of rice leaf reflectance were evaluated as indicators of brown spot. R669/R746 (the reflectance at 669 nm divided by the reflectance at 746 nm, the following ratios may be deduced by analogy), R702/R718, R692/R530, R692/R732, R535/R746, R521/R718, and R569/R718 increased significantly as the incidence of rice brown spot increased regardless of whether it's at the leaf or canopy level. R702/R718, R692/R530, R692/R732 were the best three ratios for estimating the disease severity of rice brown spot at the leaf and canopy levels. This result not only confirms the capability of hyperspectral remote sensing data in characterizing crop disease for precision pest management in the real world, but also testifies that the ratios of crop reflectance is a useful method to estimate crop disease severity. 展开更多
关键词 derivative spectrum hyperspectral reflectance ratio of spectral reflectance rice brown spot disease severity Bipolaris oryzae Helminthosporium oryzae) sensitivity analysis remote sensing
下载PDF
Optical detection of Prorocentrum donghaiense blooms based on multispectral reflectance 被引量:3
14
作者 TAO Bangyi PAN Delu +3 位作者 MAO Zhihua SHEN Yuzhang ZHU Qiankun CHEN Jianyu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第10期48-56,共9页
Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang (Yangtze) River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late sprin... Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang (Yangtze) River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late spring and early summer that lead to widespread ecologic and economic damage. A means for distinguish- ing dinoflagellate blooms from diatom (Skeletonema costatum) blooms is desired. On the basis of measure- ments of remote sensing refectance [Rrs(λ)] and inherent optical parameters, the potential of using a mul- tispectral approach is assessed for discriminating the algal blooms due to P. donghaiense from those due to S. costatum. The behavior of two reflectance ratios [R1 = Rrs(560)/Rrs(532) and Re = Rrs(708)/Rrs(665)], suggests that differentiation of P. donghaiense blooms from diatom bloom types is possible from the current band setup of ocean color sensors. It is found that there are two reflectance ratio regimes that indicate a bloom is dominated by P. donghaiense; (1) R1 〉 1.55 and R2 〈 1.0 or (2) R1 〉 1.75 and R2 ≥ 1.0. Various sensitivity analyses are conducted to investigate the effects of the variation in varying levels of chlorophyll concentration and colored dissolved organic matter (CDOM) as well as changes in the backscattering ratio (bbp/bp) on the efficacy of this muitispectral approach. Results indicate that the intensity and inherent op- tical properties of the algal species explain much of the behavior of the two ratios. Although backscattering influences the amplitude of Rrs(λ), especially in the 530 and 560 nm bands, the discrimination between P. donghaiense and diatoms is not significantly affected by the variation of bbp/bp. Since aCDOM (440) in coastal areas of the ECS is typically lower than 1.0 m-1 in most situations, the presence of CDOM does not interfere with this discrimination, even as SCDOM varies from 0.01 to 0.026 nm-1. Despite all of these effects, the dis- crimination of P. donghaiense blooms from diatom blooms based on multispectral measurements of Rrs(λ) is feasible. 展开更多
关键词 multispectral reflectance harmful algal blooms Prorocentrum donghaiense Skeletonerna costatum DISCRIMINATION
下载PDF
Estimation of As and Cu Contamination in Agricultural Soils Around a Mining Area by Reflectance Spectroscopy:A Case Study 被引量:32
15
作者 REN Hong-Yan ZHUANG Da-Fang +3 位作者 A. N. SINGH PAN Jian-Jun QIU Dong-Sheng SHI Run-He 《Pedosphere》 SCIE CAS CSCD 2009年第6期719-726,共8页
Concentrations of Iron (Fe), As, and Cu in soil samples from the fields near the Baoshan Mine in Hunan Province, China, were analyzed and soil spectral reflectance was measured with an ASD FieldSpec FR spectroradiomet... Concentrations of Iron (Fe), As, and Cu in soil samples from the fields near the Baoshan Mine in Hunan Province, China, were analyzed and soil spectral reflectance was measured with an ASD FieldSpec FR spectroradiometer (Analytical Spectral Devices, Inc., USA) under laboratory condition. Partial least square regression (PLSR) models were constructed for predicting soil metal concentrations. The data pre-processing methods, first and second derivatives (FD and SD), baseline correction (BC), standard normal variate (SNV), multiplicative scatter correction (MSC), and continuum removal (CR), were used for the spectral reflectance data pretreatments. Then, the prediction results were evaluated by relative root mean square error (RRMSE) and coefficients of determination (R 2 ). According to the criteria of minimal RRMSE and maximal R 2 , the PLSR models with the FD pretreatment (RRMSE = 0.24, R 2 = 0.61), SNV pretreatment (RRMSE = 0.08, R 2 = 0.78), and BC-pretreatment (RRMSE = 0.20, R 2 = 0.41) were considered as the final models for predicting As, Fe, and Cu, respectively. Wavebands at around 460, 1 400, 1 900, and 2 200 nm were selected as important spectral variables to construct final models. In conclusion, concentrations of heavy metals in contaminated soils could be indirectly assessed by soil spectra according to the correlation between the spectrally featureless components and Fe; therefore, spectral reflectance would be an alternative tool for monitoring soil heavy metals contamination. 展开更多
关键词 data pre-processing heavy metal regression models soil iron spectral reflectance
下载PDF
Diagnosis of Nitrogen Status in Rice Leaves with Canopy Spectral Reflectance 被引量:8
16
作者 XUELi-hong CAOWei-xing 《Agricultural Sciences in China》 CAS CSCD 2003年第3期250-257,共8页
The investigation was made on the relationship of seasonal time-course canopy spectral reflectance and ratio index to total leaf nitrogen accumulation (leaf nitrogen content per unit ground area) in rice under differe... The investigation was made on the relationship of seasonal time-course canopy spectral reflectance and ratio index to total leaf nitrogen accumulation (leaf nitrogen content per unit ground area) in rice under different nitrogen treatments. The results showed there was a close correlation between the canopy spectral reflectance and total leaf nitrogen accumulation. Ratio of near infrared to green band (R810/R560) was linearly related with total leaf nitrogen accumulation. independent of nitrogen levels and development stages. Different datasets were used to test the linear regression equation, with average estimation accuracy of 91. 22%, RMSE of 1.09 and average relative error of 0. 026. Thus, the ratio index R810/R560 of canopy spectral reflectance should be useful for non-destructive monitoring and diagnosis of nitrogen status in rice plants. 展开更多
关键词 RICE Canopy reflectance spectrum Ratio index (R810/R560) LEAF Nitrogen accumulation Nitrogen diagnosis
下载PDF
Discrimination of Transgenic Rice Based on Near Infrared Reflectance Spectroscopy and Partial Least Squares Regression Discriminant Analysis 被引量:7
17
作者 ZHANG Long WANG Shan-shan +2 位作者 DING Yan-fei PAN Jia-rong ZHU Cheng 《Rice science》 SCIE CSCD 2015年第5期245-249,共5页
Near infrared reflectance spectroscopy (NIRS), a non-destructive measurement technique, was combined with partial least squares regression discrimiant analysis (PLS-DA) to discriminate the transgenic (TCTP and mi... Near infrared reflectance spectroscopy (NIRS), a non-destructive measurement technique, was combined with partial least squares regression discrimiant analysis (PLS-DA) to discriminate the transgenic (TCTP and mi166) and wild type (Zhonghua 11) rice. Furthermore, rice lines transformed with protein gene (OsTCTP) and regulation gene (Osmi166) were also discriminated by the NIRS method. The performances of PLS-DA in spectral ranges of 4 000-8 000 cm-1 and 4 000-10 000 cm-1 were compared to obtain the optimal spectral range. As a result, the transgenic and wild type rice were distinguished from each other in the range of 4 000-10 000 cm-1, and the correct classification rate was 100.0% in the validation test. The transgenic rice TCTP and mi166 were also distinguished from each other in the range of 4 000-10 000 cm-1, and the correct classification rate was also 100.0%. In conclusion, NIRS combined with PLS-DA can be used for the discrimination of transgenic rice. 展开更多
关键词 near infrared reflectance spectroscopy genetically-modified food regulation gene protein gene partial least squares regression discrimiant analysis
下载PDF
Effects of Aerosol Vertical Inhomogeneity on the Upwelling Radiance and Satellite Remote Sensing of Surface Reflectance 被引量:2
18
作者 邱金桓 Nobuo Takeuchi 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2001年第4期539-553,共15页
There are two widely used radiative models without consideration of aerosol inhomogeneity for satellite remote sensing application, the Homogeneous Model and the Two-layer Model with aerosol in the lower layer. In thi... There are two widely used radiative models without consideration of aerosol inhomogeneity for satellite remote sensing application, the Homogeneous Model and the Two-layer Model with aerosol in the lower layer. In this paper, effects of the aerosol vertical inhomogeneity on upwelling radiance and satellite remote sensing of surface reflectance are analyzed through numerical simulations by using two models. As shown in the simulations by using 24 representative aerosol models, there is often a considerably large error in upwel-ling radiance calculated by two models (Homogeneous and Two-layer) for the short wavelength channel with strong molecular scattering, owing to the difference between molecular and aerosol scattering proper-ties. For the long wavelength channel, the error is small if aerosol optical parameters are less variable with height, but it could also be significant if there are aerosol layers with different scattering phase functions and single scattering albedo. The radiance errors by the Homogeneous Model and the Two-layer Model can be up to 31.4% and 31.5% for the clean atmosphere, and in case of turbid atmosphere 67.8% and 59.2%, respectively. The radiance error could result in a large uncertainty of surface reflectance retrievals, especially for the short wavelength channel and the strongly absorbing aerosol. For the turbid atmosphere with strong-ly absorbing aerosol, the Homogeneous Model and the Two-layer Model are not suitable for atmospheric correction application. Key words Satellite remote sensing - Aerosol inhomogeneity - Surface reflectance - Radiance 展开更多
关键词 Satellite remote sensing Aerosol inhomogeneity Surface reflectance RADIANCE
下载PDF
Features and correct application of coal vitrinite reflectance index 被引量:7
19
作者 YAO Bo-yuan LI De-ping 《Journal of Coal Science & Engineering(China)》 2012年第4期400-406,共7页
The law of mathematical statistics, which the coal vitrinite reflectance index obeys, the existing vitrinite representing deviations, and the advantages of judging coalification and the shortage of judging coal type w... The law of mathematical statistics, which the coal vitrinite reflectance index obeys, the existing vitrinite representing deviations, and the advantages of judging coalification and the shortage of judging coal type were analyzed. The advantages and disadvantages of various determination methods and the expression index and different methods of identifying vitrinite on the determination results were compared. The vitality of coal vitrinite reflectance depends on its full play the unique function of reflectance histogram and the systematic errors between different determination methods do not affect the application based on reflectance histogram are considered. 展开更多
关键词 coal vitrinite reflectance determination methods INDEX reflectance histogram APPLICATION
下载PDF
Assessment of Photochemical Reflectance Index as a Tool for Evaluation of Chlorophyll Fluorescence Parameters in Cotton and Peanut Cultivars Under Water Stress Condition 被引量:5
20
作者 Shahenshah Yasuda Yoshizumi +1 位作者 LI Mao-song Isoda Akihiro 《Agricultural Sciences in China》 CAS CSCD 2010年第5期662-670,共9页
The relationships between photochemical reflectance index (PRI) and the chlorophyll fluorescence parameters were examined to assess suitability of PRI as a remote-sensing tool for the chlorophyll fluorescence parame... The relationships between photochemical reflectance index (PRI) and the chlorophyll fluorescence parameters were examined to assess suitability of PRI as a remote-sensing tool for the chlorophyll fluorescence parameters. A greenhouse experiment was conducted using cotton and peanut crops under water stress condition. Five cotton and six peanut cultivars were grown using Andosole soil in pots maintained at two water levels; the control and water stress treatment (WS) of 100 and 50% of the daily transpiration, respectively. Higher non-photochemical quenching (NPQ) was exhibited by peanut than that of cotton by the water stress. On the other hand, the decreases of the actual quantum yield of photosystem II (△F/F'm) and PRI by the water stress in cotton were larger than those in peanut. There were positively significant correlation coefficients between PRI and △F/F'm in cotton at noon and in the afternoon including the control and WS. The correlations of PRI with NPQ were negatively significant at noon and in the afternoon for cotton, and in the afternoon for peanut. No clear relationship was found among these parameters in the morning probably due to the diurnal increase in global solar radiation. It was concluded that there would be a possibility to detect the effects of water stress on △F/F'm and NPQ by PRI with some exceptions, although PRI could not note varietals differences in △F/F'm and NPQ for each treatment. 展开更多
关键词 actual quantum yield of photosystem II Arachis hypogaea L. Gossypium hirsutum L. non-photochemicalquenching photochemical reflectance index remote sensing water stress
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部