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LOCATION OF DOUBLE BOND POSITION OF INSECT SEX PHEROMONE BY GC/MS ANALYSIS WITH CHEMICAL IONIZATION
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作者 Fan Lei KONG Jiangsu Institute of Ecomomes,Jintan Jiangsu,213200 《Chinese Chemical Letters》 SCIE CAS CSCD 1990年第2期109-112,共4页
Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the c... Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the characteristic fragment ions were high in m/z,thereby the interpretation was facilitated. 展开更多
关键词 MS GC LOCATION OF double BOND POSITION OF INSECT SEX PHEROMONE BY GC/MS analysis WITH CHEMICAL IONIZATION
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Design of a Tree Ring Structure Analysis System to Estimate the Accurate Age of Tree Species in Sri Lanka 被引量:1
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作者 Hasalanka DISSANAYAKE Sisaara PERERA 《Instrumentation》 2020年第3期50-59,共10页
Determination of an age in a particular tree species can be considered as a vital factor in forest management.In this research we have introduced a novel scheme to determine the accurate age of the tree species in Sri... Determination of an age in a particular tree species can be considered as a vital factor in forest management.In this research we have introduced a novel scheme to determine the accurate age of the tree species in Sri Lanka.This is initially developed for the tree species called‘Hora’(Dipterocarpus zeylanicus)in wet zone of Sri Lanka.Here the core samples are extracted and further analyzed by means of the different image processing techniques such as Gaussian kernel blurring,use of Sobel filters,double threshold analysis,Hough line tran sformation and etc.The operations such as rescaling,slicing and measuring are also used in line with image processing techniques to achieve the desired results.Ultimately a Graphical user interface(GUI)is developed to cater for the user requirements in a user friendly environment.It has been found that the average growth ring identification accuracy of the proposed system is 93%and the overall average accuracy of detecting the age is 81%.Ultimately the proposed system will provide an insight and contributes to the forestry related activities and researches in Sri Lanka. 展开更多
关键词 Hora(Dipterocarpus zeylanicus) Image Processing Gaussian Kernel Blurring Sobel Filter double Threshold analysis Hough Line Transformation Graphical User Interface
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Change of Annual Extreme Water Levels and Correlation with River Discharges in the Middle-lower Yangtze River: Characteristics and Possible Affecting Factors 被引量:7
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作者 YE Xuchun XU Chong-Yu +2 位作者 LI Yunliang LI Xianghu ZHANG Qi 《Chinese Geographical Science》 SCIE CSCD 2017年第2期325-336,共12页
As one of the fastest developing regions in China, the middle-lower Yangtze River (MLYR) is vulnerable to floods and droughts. With obtained time series of annual highest water level (HWL), annual lowest water lev... As one of the fastest developing regions in China, the middle-lower Yangtze River (MLYR) is vulnerable to floods and droughts. With obtained time series of annual highest water level (HWL), annual lowest water level (LWL) and the corresponding fiver discharges from three gauging stations in MLYR that covering the period 1987-2011, the current study evaluated the change character- istics of annual extreme water levels and the correlation with fiver discharges by using the methods of Vend test, Mann-Whitney-Pettitt (MWP) test and double mass analysis. Major result indicated a decreasing/increasing trend for annual HWL/LWL of all stations in MLYR during the study period. A change point in 1999 was identified for annual HWL at the Hankou and Datong stations. The year 2006 was found to be the critical year that the relationship between annual extreme water levels and fiver discharges changed in the MLYR. With contrast to annual LWL in MLYR, further investigation revealed that the change characteristics of annual HWL were highly consistent with regional precipitation in the Yangtze River Basin, while the linkage with Three Gorges Dam (TGD) operation is not strong. Our observation also pointed out that the effect of serious down cutting of the riverbed and the enlargement of the cross-section area during the initial period of TGD operation caused the downward trend of the relationship between annual LWL and river discharge. Whereas, the relatively raised river water level before the flood season due to TGD regulation since 2006 explained for the changing upward trend of the relationship between annual HWL and river discharge. 展开更多
关键词 extreme water level water level-discharge relationship double mass analysis Yangtze River
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Detection of radio-frequency interference signals from AMSR-E data over the United States with snow cover 被引量:5
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作者 Chengcheng FENG Xiaolei ZOU Juan ZHAO 《Frontiers of Earth Science》 CSCD 2016年第2期195-204,共10页
Radio Frequency Interference (RFI) causes severe contamination to passive and active microwave sensing observations and corresponding retrieval products. RFI signals should be detected and filtered before applying t... Radio Frequency Interference (RFI) causes severe contamination to passive and active microwave sensing observations and corresponding retrieval products. RFI signals should be detected and filtered before applying the microwave data to retrieval and data assimilation. It is difficult to detect RFI over land surfaces covered by snow because of the scattering effect of snow surface. The double principal component analysis (DPCA) method is adopted in this study, and its ability in identifying RFI signals in AMSR-E data over snow covered regions is investigated. Results show that the DPCA method can detect RFI signals effectively in spite of the impact of snow scattering, and the detected RFI signals persistent over time. Compared to other methods, such as PCA and normalized PCA, DPCA is more robust and suitable for operational application. 展开更多
关键词 Radio Frequency Interference (RFI) AMSR-E double principal component analysis (DPCA)
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