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1.
Opt Express ; 29(9): 13359-13372, 2021 Apr 26.
Article in English | MEDLINE | ID: mdl-33985071

ABSTRACT

Multispectral imaging plays a significant role in coastal mapping and monitoring applications. For tasks involving the integration of multiple overlapped images, precise co-registration of the multisource satellite images is a crucial preliminary step. However, due to the limited terrestrial area and insufficient landscape features, the traditional methods become less efficient or even invalid in offshore island environments. This study addresses the problem by exploring the feasibility of using bathymetry information for geometric registration of satellite imagery. Instead of using the ground control points (GCPs) or extracting the tie points from the landscape features, the band ratio values are extracted from the multispectral images and are subsequently matched between different images through a correlation-based similarity measure. By searching the optimum correlation within the positioning uncertainty radius, the translation between two satellite images is estimated. Thus, the geometric inconsistency between the multispectral images of different sources and resolutions is effectively reduced. This result is obtained by using the ample bathymetry features without the aid of the GCPs and the in-situ bathymetry data. The experimental results using GeoEye-1, Sentinel-2, and Landsat-8 images at Ganquan Island show that for an island setting with a limited terrestrial area, the developed method achieves sub-pixel registration accuracy (less than 2 m) in planimetry. The effect of the nonlinearity and outliers are accounted for using the Spearman correlation measure. The improvement in image alignment enables the integration of multispectral images of different sources and resolutions for producing an accurate and consistent interpretation for coastal comparative and synergistic applications.

2.
Huan Jing Ke Xue ; 41(11): 5016-5026, 2020 Nov 08.
Article in Chinese | MEDLINE | ID: mdl-33124245

ABSTRACT

The water quality of a small watershed will directly affect the water quality safety of the entire watershed. The Lidu small watershed of the Fulin District in Chongqing was selected for this study. The characteristics of runoff and the microbial community in the receiving water body were analyzed by high-throughput sequencing technology. The effects of the physical and chemical factors of the water body on the microbial diversity in the water body were also investigated. The results showed that the small watershed of Lidu was an important source of nitrite and dissolved organic carbon for the receiving water. There was no significant difference in the microbial richness and diversity of the water flowing through different pollution sources in the small watershed, and the microbial diversity index was negatively correlated with the total phosphorus (r -0.79--0.84, P ≤ 0.01) and phosphate (r -0.71--0.80, P ≤ 0.01) of the water. At the phylum level, Actinobacteria (37.33% ±14.69%) accounted for the largest proportion of runoff flowing through the agricultural area, followed by Proteobacteria (32.53% ±7.18%), Cyanobacteria (14.65% ±22.64%), Bacteroidetes (8.50% ±3.67%), and others. Proteobacteria (43.67% ±10.80%) accounted for the largest proportion of runoff flowing through the industrial area, followed by Bacteroidetes (25.33% ±11.97%), Actinobacteria (24.17% ±14.66%), Firmicutes (2.53% ±0.72%), and others. At the genus level, hgcI_clade (19.08% ±13.46%) accounted for the largest proportion of runoff flowing through the agricultural area, followed by CL 500-29 _marine_group (7.40% ±4.44%), Limnohabitans (7.05% ±3.14%), and others. Flavobacterium (20.40% ±12.37%) accounted for the largest proportion of runoff flowing through the industrial area, followed by hgcI_clade (15.30% ±11.11%), Acinetobacter (9.33% ±11.50%), and others. The Flavobacterium in the runoff water may be related to the input of industrial sources in the watershed. Nitrous nitrogen, total phosphorus, phosphate, pH, and Zn2+ were the main environmental factors that affected the microbial community in the small watershed. They can explain the variance of microbial community 0.26, 0.21, 0.20, 0.15, and 0.14, respectively. DOC, nitrate nitrogen, and heavy metal ions such as Cu2+, Zn2+, Mn2+, and As3+ were also related to the proportion of some microorganisms in the water.


Subject(s)
Environmental Monitoring , Metals, Heavy , Nitrogen/analysis , Phosphorus/analysis , Water Quality
3.
Chemosphere ; 240: 124946, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31726598

ABSTRACT

Efficient oil separation is the most desirable, but still challenging solution for the waste crude oil problem. This study developed biosurfactant surfactin as a novel pH-switchable biodemulsifier for efficient oil separation. As found, surfactin demulsification achieved a quite well oil separation ratio of over 95% on model emulsions after 20 min at 50 °C. The validity of this demulsification process should be mainly based on the readily lost stabilization ability of surfactin in emulsions triggered by acid addition. Then, surfactin (0.2 g/L) treatment with the aid of ethanol (2%) to improve its distribution could recover over 95% of oil from waste crude oil. After treated by surfactin, the separated oil phase contains tiny water (less than 0.5%) and thus can be reused for resource recycling to reach a compromised balance between satisfying the strict environmental regulations and decreasing the high treatment costs. Hence, in consideration of high demulsification efficiency, environmental-friendly properties and cost-efficiency, surfactin has a great potential for industrial applications for oil recovery from waste crude oil which is a severe problem presents in most of the petroleum-related factories.


Subject(s)
Emulsions/chemistry , Fuel Oils , Petroleum , Surface-Active Agents/pharmacology , Hydrogen-Ion Concentration
4.
J Mol Graph Model ; 93: 107450, 2019 12.
Article in English | MEDLINE | ID: mdl-31542686

ABSTRACT

Molecular dynamics (MD) simulations were used to study the thermodynamic properties of asphalt binder components, namely asphaltene, and other solvents, such as pentane or toluene, before and after adding pentane or toluene. The two systems were compared by MD simulation under lots of molecules, temperature and pressure to predict their internal energy, structure, and density as a function of time or distance between molecules. Then the simulation results of the two systems were analyzed and compared to determine the influence of different solvents on asphaltene aggregation behavior. The results show that the asphaltenes with pentane or toluene in the two systems have different structure and dynamic characteristics and will produce different precipitation and aggregation characteristics. The aggregation behavior of asphaltene at water - oil interface with or without pentane or toluene was studied. The relationship between the molecular structure and the aggregation of asphaltene in different solvents was investigated.


Subject(s)
Oils/chemistry , Polycyclic Aromatic Hydrocarbons/chemistry , Solvents/chemistry , Water/chemistry , Molecular Dynamics Simulation
5.
Huan Jing Ke Xue ; 39(5): 2400-2411, 2018 May 08.
Article in Chinese | MEDLINE | ID: mdl-29965541

ABSTRACT

In order to explore the variation in soil microbial community diversity in paddy fields with different irrigation periods, we collected in situ rice field soils during different biogas irrigation periods and analyzed the microbial community structures of these soils by high-throughput sequencing. The results showed that as the biogas irrigation period increased, the soil pH decreased gradually, while organic matter, nitrate nitrogen, phosphate, and other nutrients were accumulated. Years of continued biogas irrigation was not conducive to improving rice yields. The results showed that as the biogas irrigation period increased, the richness in microbial species in paddy soils decreased gradually, and the diversity in the microbial communities was also reduced. Proteobacteria accounts for the largest proportion in rice paddy soil with biogas slurry irrigation. With the increase of biogas irrigation years, the proportion of ß-Proteobacteria, Bacteroidia, Bacteroidales, Burkholderiales, Bacteroides, and Thiobacillus increased, while the proportion of Gemmatimonadetes and α-Proteobacteria decreased gradually. Dissolved organic carbon (F=2.67, P=0.09) had the greatest effect on microbial community structures in the studied paddy soils.


Subject(s)
Bacteria/classification , Biofuels , Soil Microbiology , Soil/chemistry , Agricultural Irrigation , High-Throughput Nucleotide Sequencing , Oryza
6.
Environ Sci Pollut Res Int ; 22(7): 5538-51, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25339527

ABSTRACT

In order to explore the contributions of wet deposition and runoff formed by rainfall events to the water body mercury burden in Three Gorges Reservoir (TGR), we conducted a 1-year successive study on the deposition fluxes and runoff output characteristics of total mercury (THg) and methylmercury (TMeHg) in a typical small agricultural watershed in TGR areas. The results showed that the annual volume-weighted concentration (VWC) of THg and TMeHg was 18 and 0.23 ng L(-1), respectively. Particulate form was the main form of both THg and TMeHg, accounting for 61 % of THg and 59 % of TMeHg. The annual deposition fluxes of THg and TMeHg in rainfall were 13 ± 2.4 µg m(-2) year(-1) and 174 ± 52 ng m(-2) year(-1), respectively. The VWCs of THg and TMeHg in runoff were 10 ± 6.5 and 0.15 ± 0.15 ng L(-1). The annual output fluxes of THg and TMeHg to TGR from study area were 1.2 ± 0.73 µg m(-2) year(-1) and 17 ± 16 ng m(-2) year(-1), respectively.


Subject(s)
Environmental Monitoring/statistics & numerical data , Mercury/analysis , Methylmercury Compounds/analysis , Rivers/chemistry , Water Pollutants, Chemical/analysis , Agriculture , China , Chromatography, Gas , Chromatography, Ion Exchange , Environmental Monitoring/methods , Rain
7.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(7): 1922-6, 2014 Jul.
Article in Chinese | MEDLINE | ID: mdl-25269309

ABSTRACT

For improving the estimation accuracy of soil organic matter content of the north fluvo-aquic soil, wavelet transform technology is introduced. The soil samples were collected from Tongzhou district and Shunyi district in Beijing city. And the data source is from soil hyperspectral data obtained under laboratory condition. First, discrete wavelet transform efficiently decomposes hyperspectral into approximate coefficients and detail coefficients. Then, the correlation between approximate coefficients, detail coefficients and organic matter content was analyzed, and the sensitive bands of the organic matter were screened. Finally, models were established to estimate the soil organic content by using the partial least squares regression (PLSR). Results show that the NIR bands made more contributions than the visible band in estimating organic matter content models; the ability of approximate coefficients to estimate organic matter content is better than that of detail coefficients; The estimation precision of the detail coefficients fir soil organic matter content decreases with the spectral resolution being lower; Compared with the commonly used three types of soil spectral reflectance transforms, the wavelet transform can improve the estimation ability of soil spectral fir organic content; The accuracy of the best model established by the approximate coefficients or detail coefficients is higher, and the coefficient of determination (R2) and the root mean square error (RMSE) of the best model for approximate coefficients are 0.722 and 0.221, respectively. The R2 and RMSE of the best model for detail coefficients are 0.670 and 0.255, respectively.


Subject(s)
Least-Squares Analysis , Organic Chemicals/analysis , Soil/chemistry , Wavelet Analysis , Models, Theoretical
8.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(1): 201-6, 2014 Jan.
Article in Chinese | MEDLINE | ID: mdl-24783561

ABSTRACT

The present study aims to assess the feasibility of multi-spectral data in monitoring soil organic matter content. The data source comes from hyperspectral measured under laboratory condition, and simulated multi-spectral data from the hyperspectral. According to the reflectance response functions of Landsat TM and HJ-CCD (the Environment and Disaster Reduction Small Satellites, HJ), the hyperspectra were resampled for the corresponding bands of multi-spectral sensors. The correlation between hyperspectral, simulated reflectance spectra and organic matter content was calculated, and used to extract the sensitive bands of the organic matter in the north fluvo-aquic soil. The partial least square regression (PLSR) method was used to establish experiential models to estimate soil organic matter content. Both root mean squared error (RMSE) and coefficient of the determination (R2) were introduced to test the precision and stability of the modes. Results demonstrate that compared with the hyperspectral data, the best model established by simulated multi-spectral data gives a good result for organic matter content, with R2=0.586, and RMSE=0.280. Therefore, using multi-spectral data to predict tide soil organic matter content is feasible.


Subject(s)
Organic Chemicals/analysis , Soil/chemistry , Least-Squares Analysis , Regression Analysis
9.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 25(8): 738-40, 2005 Aug.
Article in Chinese | MEDLINE | ID: mdl-16152836

ABSTRACT

OBJECTIVE: To observe the effect of children' bronchial asthma in the stage of attack treated by Hailong Juanxiao Recipe combined with Kechuanping sticking on Yongquan acupoint (HKSYA). METHODS: One hundred and fifty children aging between 4-14 years old with bronchial asthma were randomly divided into HKSYA group (treated group, 75 cases) and Western medicine control group (control group, 75 cases). The clinical efficacy, eosinophilis (EOS) in peripheral blood and serum IgE of the patients were determined after 2 weeks of treatment. RESULTS: The clinical efficacy in the treated group was 89.3%, compared with the control group (64.0%), the difference was significant (P < 0.05). EOS and IgE in both groups after treatment were obviously lower with significant difference when compared with before treatment (P < 0.01 or P < 0.05). CONCLUSION: HKSYA could improve the clinical symptoms and the observation item, and enhance the clinical efficacy.


Subject(s)
Acupuncture Points , Asthma/drug therapy , Drugs, Chinese Herbal/therapeutic use , Phytotherapy , Adolescent , Anti-Asthmatic Agents/administration & dosage , Anti-Asthmatic Agents/therapeutic use , Child , Child, Preschool , Combined Modality Therapy , Double-Blind Method , Drugs, Chinese Herbal/administration & dosage , Female , Humans , Male
10.
Zhonghua Yi Shi Za Zhi ; 32(2): 94-8, 2002 Apr.
Article in Chinese | MEDLINE | ID: mdl-12639428

ABSTRACT

The academic contending from cold school and warm school of pediatrics was derived from Qian Yi's and Chen Wenzhong's therapeutic opinions for measles and smallpox in the Song dynasty. The former claimed the use of cold and cool drugs, while the latter, maintained the use of warm and hot drugs. During the Jin, Yuan, Ming and Qing dynasties, physicians continually revised and supplied their therapeutic methods and started the academic contending in almost all fields of pediatrics, including therapeutic opinion for measles and smallpox, exogenous pathogenic diseases of children, miscellaneous diseases of children etc., which improved the further research on basic theory of pediatrics, such as constitution, physiological and pathological characteristics of children, and also pushed forward the academic development of pediatrics of traditional Chinese medicine.


Subject(s)
Pediatrics/history , Philosophy, Medical/history , Schools, Medical/history , China , History, Medieval
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