Modified potential ecological risk index (MRI) was proposed based on the potential ecological risk index (RI) and risk assessment code (RAC) by modifying an index. The modified index was relevant to the chemical...Modified potential ecological risk index (MRI) was proposed based on the potential ecological risk index (RI) and risk assessment code (RAC) by modifying an index. The modified index was relevant to the chemical speciation of heavy metals. Xiawan Port, a typical region contaminated by industrial production, was selected as a case study area. The total concentrations and chemical speciation of heavy metals in sediments of Xiawan Port were analyzed. The experimental data indicate that Xiawan Port is seriously polluted by heavy metals, especially by Cd. The risks of heavy metals are evaluated by RI, RAC and MRI, respectively. The resluts of MRI show that the risks of heavy metals are in the decreasing order of Cd〉Pb〉Cu〉Zn. Comparison of results by different methods reveals that MRI integrates the characters of RI and RAC. MRI is recognized to be useful for risk managemnt of heavy metals in sediments.展开更多
A self-normalized statistic the modified modal scintillation index MMSI is proposed and defined as the variance of the modulus of modal excitation normalized by the square of its expected value over some observation i...A self-normalized statistic the modified modal scintillation index MMSI is proposed and defined as the variance of the modulus of modal excitation normalized by the square of its expected value over some observation intervals.It is proved in an analytical form that the MMSI is a depth dependent signature and independent of the source level and the source range under the condition of the ideal waveguide while the classical modal scintillation index MSI depends on both the source level and the source range.The MSI and the MMSI in the Pekeris waveguide at 70 Hz are simulated with different source levels and source ranges by the Kraken normal mode model.The simulation results are consistent with the theoretical deduction.The MMSI probability density functions PDFs of different normal modes for surface and submerged sources are calculated using the mode filtering methods with the same variations of vertical motions.It is indicated that the PDFs can be used to separate the submerged and the surface sources except for the fourth mode.展开更多
BACKGROUND:This study aimed to determine whether modified shock index(MSI)is associated with mortality that is superior to heart rate,blood pressure,or the shock index(SI).in emergency patients.METHODS:A retrospective...BACKGROUND:This study aimed to determine whether modified shock index(MSI)is associated with mortality that is superior to heart rate,blood pressure,or the shock index(SI).in emergency patients.METHODS:A retrospective database review was performed on 22 161 patients who presented to Peking Union Medical College Hospital Emergency Department and received intravenous fluids from January 1 to December 31,2009.We gathered data of the patients on age,gender,vital signs,levels of consciousness,presenting complaints,and SI and MSI were calculated for all patients.RESULTS:Multivariate regression analysis was performed to determine the correlation between risk factors and outcome.There is a significant correlation between emergency patient mortality rate and patient's vital signs obtained at the triage desk(HR>120 beats/min,systolic BP<90 mmHg,diastolic BP<60 mmHg).MSI is a stronger predictor of emergency patient mortality compared to heart rate and blood pressure alone,whereas SI does not have a significant correlation with emergency patient mortality rate.CONCLUSION:MSI is a clinically significant predictor of mortality in emergency patients.It may be better than using heart rate and blood pressure alone.SI is not significantly correlated with the mortality rate of the emergency patient.展开更多
Spatio-temporal dynamic monitoring of soil moisture is highly important to management of agricultural and vegetation eco-systems.The temperature-vegetation dryness index based on the triangle or trapezoid method has b...Spatio-temporal dynamic monitoring of soil moisture is highly important to management of agricultural and vegetation eco-systems.The temperature-vegetation dryness index based on the triangle or trapezoid method has been used widely in previous studies.However,most existing studies simply used linear regression to construct empirical models to fit the edges of the feature space.This requires extensive data from a vast study area,and may lead to subjective results.In this study,a Modified Temperature-Vegetation Dryness Index(MTVDI)was used to monitor surface soil moisture status using MODIS(Moderate-resolution Imaging Spectroradiometer)remote sensing data,in which the dry edge conditions were determined at the pixel scale based on surface energy balance.The MTVDI was validated by field measurements at 30 sites for 10 d and compared with the Temperature-Vegetation Dryness Index(TVDI).The results showed that the R^(2) for MTVDI and soil moisture obviously improved(0.45 for TVDI,0.69 for MTVDI).As for spatial changes,MTVDI can also better reflect the actual soil moisture condition than TVDI.As a result,MTVDI can be considered an effective method to monitor the spatio-temporal changes in surface soil moisture on a regional scale.展开更多
Subsurface stormflow is a dominant runoff mechanism in steep humid mountainous areas.An insite measurement of subsurface stormflow suggests that the bedrock surface plays an important role in the runoff generation and...Subsurface stormflow is a dominant runoff mechanism in steep humid mountainous areas.An insite measurement of subsurface stormflow suggests that the bedrock surface plays an important role in the runoff generation and routing process,which was rarely adopted in hydrological modelling studies.To improve the runoff simulation performance,the bedrock surface topographic index is introduced,and a modified TOPMODEL based on the bedrock surface topographic index is developed to simulate the runoff.The modified TOPMODEL is applied to the Huangbengliu(HBL),a steep watershed in Gongga Mountain,and proved to be more appropriate for the HBL watershed,especially for peak simulation.The Nash-Sutcliffe model efficiency(NSE)is improved from 0.24 to 0.58 in the calibration period and from 0.40 to 0.62 in the verification period.The result of this study can advance the understanding of the mechanism of flash floods and contribute flood control and disaster prevention in the HBL watershed and similar areas.展开更多
Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is...Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is often difficult to distinguish between algal blooms and aquatic vegetation due to their similar spectral characteristics. In this paper, we used modified vegetation presence frequency index(VPF) based on Moderate-resolution Imaging Spectroradiometer(MODIS) imagery to distinguish algal blooms from aquatic vegetation, and analyzed the spatial and temporal variations of algal blooms and aquatic vegetation from a phenological perspective for five large natural lakes with frequent algal bloom outbreaks in China from 2019 to 2020. We simplified the VPF method to make it with a higher spatial transferability so that it could be applied to other lakes in different climatic zones. Through accuracy validation, we found that the modified VPF method can effectively distinguish between algal blooms and aquatic vegetation, and the results vary from lake to lake. The highest accuracy of 97% was achieved in Hulun Lake, where the frequency of algal outbreaks is low and the extent of aquatic vegetation is stable, while the lowest accuracy of 76% was achieved in Dianchi Lake, which is rainy in summer and the lake is small. Analyses suggests that the time period when algal blooms occur most frequently might not coincide with that when they have the largest area. However, in most cases these two are close in terms of time period. The modified VPF method has a broad scope of application, is easy to implement, and has a high practical value. Furthermore, the method could be established using only a small amount of measured data, which is useful for water quality monitoring on large spatial scales.展开更多
Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysica...Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysical consistency constraint methods,which are mutually independent.Currently,there is a need for joint inversion methods that can comprehensively consider the structural consistency constraints and petrophysical consistency constraints.This paper develops the structural similarity index(SSIM)as a new structural and petrophysical consistency constraint for the joint inversion of gravity and vertical gradient data.The SSIM constraint is in the form of a fraction,which may have analytical singularities.Therefore,converting the fractional form to the subtractive form can solve the problem of analytic singularity and finally form a modified structural consistency index of the joint inversion,which enhances the stability of the SSIM constraint applied to the joint inversion.Compared to the reconstructed results from the cross-gradient inversion,the proposed method presents good performance and stability.The SSIM algorithm is a new joint inversion method for petrophysical and structural constraints.It can promote the consistency of the recovered models from the distribution and the structure of the physical property values.Then,applications to synthetic data illustrate that the algorithm proposed in this paper can well process the synthetic data and acquire good reconstructed results.展开更多
Otindag Sandy Land in China is an important ecological barrier to Beijing;the changes in its ecological quality are major concerns for sustainable development and planning of this area.Based on principal component ana...Otindag Sandy Land in China is an important ecological barrier to Beijing;the changes in its ecological quality are major concerns for sustainable development and planning of this area.Based on principal component analysis and path analysis,we first generated a modified remote sensing ecological index(MRSEI)coupled with satellite and ground observational data during 2001–2020 that integrated four local indicators(greenness,wetness,and heatness that reflect vegetation status,water,and heat conditions,respectively,as well as soil erosion).Then,we assessed the ecological quality in Otindag Sandy Land during 2001–2020 based on the MRSEI at different time scales(i.e.,the whole year,growing season,and non-growing season).MRSEI generally increased with an upward rate of 0.006/a during 2001–2020,with clear seasonal and spatial variations.Ecological quality was significantly improved in most regions of Otindag Sandy Land but degraded in the southern part.Regions with ecological degradation expanded to 18.64%of the total area in the non-growing season.The area with the worst grade of MRSEI shrunk by 15.83%of the total area from 2001 to 2020,while the area with the best grade of MRSEI increased by 9.77%of the total area.The temporal heterogeneity of ecological conditions indicated that the improvement process of ecological quality in the growing season may be interrupted or deteriorated in the following non-growing season.The implementation of ecological restoration measures in Otindag Sandy Land should not ignore the seasonal characteristics and spatial heterogeneity of local ecological quality.The results can explore the effectiveness of ecological restoration and provide scientific guides on sustainable development measures for drylands.展开更多
To understand the impacts of large-scale circulation during the evolution of E1 Nifio cycle on tropical cyclones (TC) is important and useful for TC forecast. Based on best-track data from the Joint Typhoon Warning ...To understand the impacts of large-scale circulation during the evolution of E1 Nifio cycle on tropical cyclones (TC) is important and useful for TC forecast. Based on best-track data from the Joint Typhoon Warning Center and reanalysis data from National Centers for Environmental Prediction for the period 1975- 2014, we investigated the influences of two types of E1 Nifio, the eastern Pacific E1 Nifio (EP-E1 Nifio) and central Pacific E1 Nifio (CP-E1 Nifio), on global TC genesis. We also examined how various environmental factors contribute to these influences using a modified genesis potential index (MGPI). The composites reproduced for two types of E1 Nifio, from their developing to decaying phases, were able to qualitatively replicate observed cyclogenesis in several basins except for the Arabian Sea. Certain factors of MGPI with more influence than others in various regions are identified. Over the western North Pacific, five variables were all important in the two E1Nifio types during developing summer (July-August-September) and fall (October- November-December), and decaying spring (April-May-June) and summer. In the eastern Pacific, vertical shear and relative vorticity are the crucial factors for the two types of El Nifio during developing and decaying summers. In the Atlantic, vertical shear, potential intensity and relative humidity are important for the opposite variation of EP- and CP-EI Nifios during decaying summers. In the Southern Hemisphere, the five variables have varying contributions to TC genesis variation during peak season (January-February-March) for the two types of E1 Nifio. In the Bay of Bengal, relative vorticity, humidity and omega may be responsible for clearly reduced TC genesis during developing fall for the two types and slightly suppressed TC cyclogenesis during EP-E1 Nifio decaying spring. In the Arabian Sea, the EP-E1 Nifio generates a slightly positive anomaly of TC genesis during developing falls and decaying springs, but the MGPI failed to capture this variation.展开更多
Complex processes often work with multiple operation regions, it is critical to develop effective monitoring approaches to ensure the safety of chemical processes. In this work, a discriminant local consistency Gaussi...Complex processes often work with multiple operation regions, it is critical to develop effective monitoring approaches to ensure the safety of chemical processes. In this work, a discriminant local consistency Gaussian mixture model(DLCGMM) for multimode process monitoring is proposed for multimode process monitoring by integrating LCGMM with modified local Fisher discriminant analysis(MLFDA). Different from Fisher discriminant analysis(FDA) that aims to discover the global optimal discriminant directions, MLFDA is capable of uncovering multimodality and local structure of the data by exploiting the posterior probabilities of observations within clusters calculated from the results of LCGMM. This may enable MLFDA to capture more meaningful discriminant information hidden in the high-dimensional multimode observations comparing to FDA. Contrary to most existing multimode process monitoring approaches, DLCGMM performs LCGMM and MFLDA iteratively, and the optimal subspaces with multi-Gaussianity and the optimal discriminant projection vectors are simultaneously achieved in the framework of supervised and unsupervised learning. Furthermore, monitoring statistics are established on each cluster that represents a specific operation condition and two global Bayesian inference-based fault monitoring indexes are established by combining with all the monitoring results of all clusters. The efficiency and effectiveness of the proposed method are evaluated through UCI datasets, a simulated multimode model and the Tennessee Eastman benchmark process.展开更多
Let G be simple connected graph with the vertex and edge sets V (G) and E (G), respectively. The Schultz and Modified Schultz indices of a connected graph G are defined as and , where d (u, v) is the distance between ...Let G be simple connected graph with the vertex and edge sets V (G) and E (G), respectively. The Schultz and Modified Schultz indices of a connected graph G are defined as and , where d (u, v) is the distance between vertices u and v?;dv is the degree of vertex v of G. In this paper, computation of the Schultz and Modified Schultz indices of the Jahangir graphs J5,m is proposed.展开更多
One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearin...One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearing characteristics. Viscosity Index (VI) is one approach used widely in the lubricating field to assess the variation of viscosity with temperature. The VI of both mineral and synthetic base oils can be improved by the addition of polymeric viscosity modifiers (VMs). VI improvement by VMs is widely attributed to the polymer coil size expanding with increasing temperature. However, there is very little physical data supporting this generally accepted mechanism. To address this issue, intrinsic viscosity measurements and Small-Angle Neutron Scattering (SANS) have been used to study the variation of polymer coil size with changing temperature and concentration in a selection of solvents. The results will show that coil size expansion with temperature is not necessary to achieve significant elevation of viscosity index.展开更多
Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain er...Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain erosive potential, and precipitation concentration in the Mantaro River Basin, in the Peruvian Andes, which is important for agriculture and energy production in Peru. We assumed the Intergovernmental Panel on Climate Change (IPCC) AIB greenhouse gas emission scenario and simulated the global climate change by the HadCM3 global climate model. Due to the steepness of the mountain slopes and the narrowness of the river valley, this study uses the downscaling of the global model simulations by the regional Eta model down to 2o-km resolution. The downscaling projections show decrease in the monthly precipitation with respect to the baseline period, especially during the rainy season, between February and April, until the end of the 21st century. Meanwhile, a progressive increase in the monthly evaporation from the baseline period is projected. The Modified Fournier Index (MFI) shows a statistically significant downward trend in the Mantaro River Basin, whieh suggests a possible reduction in the rain erosive potential. The Precipitation Concentration Index (PCI) shows a statistically significant increasing trend, which indicates increasingly more irregular temporal distribution of precipitation towards the end of the century. The results of this study allow us to conclude that there should be a gradual increase in water deficit and precipitation concentration. Both changes can be negative for agriculture, power generation, and water supply in the Mantaro River Basin in Peru.展开更多
Determination of the work index of Gyel-Buruku columbite ore sample in Plateau state, Nigeria, was investigated. The sample of the columbite ore was sourced from Gyel village in Jos East Local Government Area of Plate...Determination of the work index of Gyel-Buruku columbite ore sample in Plateau state, Nigeria, was investigated. The sample of the columbite ore was sourced from Gyel village in Jos East Local Government Area of Plateau state, Nigeria. The “reference ores (granites)” samples were sourced from Jiche and Gurum villages of Plateau state respectively. The reference ores and columbite ore of known weights were ground and pulverized. 80% passing size for the columbite ore, Jiche and Gurum granites samples was obtained at 100 μm sieve size for the feeds and products respectively. The work indexes of reference ores i.e. Jiche and Gurum granites were used to calculate the work index of the Gyel columbite ore sample. The values of 3.42 kWh/ton and 2.72 kWh/ton were obtained respectively for the two different reference granites ores samples used and 3.07 kWh/ton was calculated as their average and determined as the value of the work index of the Gyel-Bukuru columbite ore sample. This work index value obtained for the Gyel-Buruku columbite ore sample lies favourably within the work indexes of 3.94 - 10.81 kWh/ton for columbite minerals sighted in the literatures.展开更多
A method was developed to make a quantitative analysis of the microstructure of asphalt modified with styrene-butadiene-styrene block(SBS) copolymer. Moreover, both mixed and branched SBS were employed in the prepar...A method was developed to make a quantitative analysis of the microstructure of asphalt modified with styrene-butadiene-styrene block(SBS) copolymer. Moreover, both mixed and branched SBS were employed in the preparation of modified asphalt. By sampling specimens from the top, middle, and bottom, a number of microscope slides were made and 400 times micro images were gained. Binarized with the software of MATLAB, the images then went to the process of distribution test, when four typical distributions were employed to investigate the distribution of modifi er spread in asphalt. The distribution characteristic and its parameter were both found. The results show that asphalt phase clearly obeys Poisson distribution, and its parameter, λ, is bond up with the condition SBS performs in. Based on this parameter, indexes can be set up to evaluate the structure of the mixture and its performance as well. Compared with that modifi ed with mixed SBS, the asphalt modifi ed with branched SBS has better performance but worse stability, for it is easier to segregate.展开更多
Objective:To study the differences between the lipid profiles of the subjects whose parents are having known non-modifiable risk factors such as obesity,hypertension(HTN),myocardial infarction and diabetes,and compare...Objective:To study the differences between the lipid profiles of the subjects whose parents are having known non-modifiable risk factors such as obesity,hypertension(HTN),myocardial infarction and diabetes,and compare them with the lipid profiles of the subjects whose parents are not having those risk factors.Methods:A total of 402 subjects were recruited to this study.A detailed questionnaire which included information on the past medical history,height,weight,blood pressure,physical activity,smoke,alcohol,family history of coronary heart disease,HTN.diabetics and obesity.Basic demographic data and dietary habits were completed by all participants.Blood samples were obtained from all subjects after 14 h.Lipid profiles were analyzed using automated analyzer.The results were analyzed using SPSS software packages.Results:The mean body mass index of the population was well below the cut-off value of obesity(>24.5 kg/m") and high risk of future cardiovascular disorder(CVD) events in this age group.The mean levels of total cholesterol(TC),triglycerides(TG) and TC/high density lipoprotein(HDL) were less than the risk levels indicative of future CVD events according to the ATP Ⅲ cut-off values.However the mean HDL level in our population was slightly greater than the cut-off value while the mean low density lipoprotein level was almost similar to the risk level.Differences were observed when the subjects without history of maternal obesity were compared with subjects with history of maternal obesity.The greater percentage of subjects who are having risk levels of body mass index.TC.low density lipoprotein.TG.and TC/HDI.indicated that maternal obesity contributed to the greater susceptibility of developing CVD risk in their offspring.Conclusions:Advancing age may result in changes that could be atherogenic in the future.Such atherogenic changes have already initialed when the subjects are about 21 years old.The incidence of atherogenic changes is far greater when mothers who are having any of the risk factors such as obesity,diabetes,HTN and myocardial infarction than that fathers who are havine similar risk factors.展开更多
基金Projects (51039001, 50978087, 51009063, 50808071) supported by the National Natural Science Foundation of ChinaProject (SX2010-026) supported by State Council Three Gorges Project Construction Committee Executive Office,China+2 种基金Project (2009ZX07212-001) supported by Ministry of Environmental Protection of ChinaProject (BYHGLC-2010-02) supported by Guangzhou Water Authority,ChinaProject (CX2010B157) supported by Hunan Provincial Innovation Foundation for Postgraduate,China
文摘Modified potential ecological risk index (MRI) was proposed based on the potential ecological risk index (RI) and risk assessment code (RAC) by modifying an index. The modified index was relevant to the chemical speciation of heavy metals. Xiawan Port, a typical region contaminated by industrial production, was selected as a case study area. The total concentrations and chemical speciation of heavy metals in sediments of Xiawan Port were analyzed. The experimental data indicate that Xiawan Port is seriously polluted by heavy metals, especially by Cd. The risks of heavy metals are evaluated by RI, RAC and MRI, respectively. The resluts of MRI show that the risks of heavy metals are in the decreasing order of Cd〉Pb〉Cu〉Zn. Comparison of results by different methods reveals that MRI integrates the characters of RI and RAC. MRI is recognized to be useful for risk managemnt of heavy metals in sediments.
基金The National Natural Science Foundation of China(No.11104029)
文摘A self-normalized statistic the modified modal scintillation index MMSI is proposed and defined as the variance of the modulus of modal excitation normalized by the square of its expected value over some observation intervals.It is proved in an analytical form that the MMSI is a depth dependent signature and independent of the source level and the source range under the condition of the ideal waveguide while the classical modal scintillation index MSI depends on both the source level and the source range.The MSI and the MMSI in the Pekeris waveguide at 70 Hz are simulated with different source levels and source ranges by the Kraken normal mode model.The simulation results are consistent with the theoretical deduction.The MMSI probability density functions PDFs of different normal modes for surface and submerged sources are calculated using the mode filtering methods with the same variations of vertical motions.It is indicated that the PDFs can be used to separate the submerged and the surface sources except for the fourth mode.
文摘BACKGROUND:This study aimed to determine whether modified shock index(MSI)is associated with mortality that is superior to heart rate,blood pressure,or the shock index(SI).in emergency patients.METHODS:A retrospective database review was performed on 22 161 patients who presented to Peking Union Medical College Hospital Emergency Department and received intravenous fluids from January 1 to December 31,2009.We gathered data of the patients on age,gender,vital signs,levels of consciousness,presenting complaints,and SI and MSI were calculated for all patients.RESULTS:Multivariate regression analysis was performed to determine the correlation between risk factors and outcome.There is a significant correlation between emergency patient mortality rate and patient's vital signs obtained at the triage desk(HR>120 beats/min,systolic BP<90 mmHg,diastolic BP<60 mmHg).MSI is a stronger predictor of emergency patient mortality compared to heart rate and blood pressure alone,whereas SI does not have a significant correlation with emergency patient mortality rate.CONCLUSION:MSI is a clinically significant predictor of mortality in emergency patients.It may be better than using heart rate and blood pressure alone.SI is not significantly correlated with the mortality rate of the emergency patient.
基金Under the auspices of the National Natural Science Foundation of China(No.41801180)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2020JQ415,2019JQ-767)。
文摘Spatio-temporal dynamic monitoring of soil moisture is highly important to management of agricultural and vegetation eco-systems.The temperature-vegetation dryness index based on the triangle or trapezoid method has been used widely in previous studies.However,most existing studies simply used linear regression to construct empirical models to fit the edges of the feature space.This requires extensive data from a vast study area,and may lead to subjective results.In this study,a Modified Temperature-Vegetation Dryness Index(MTVDI)was used to monitor surface soil moisture status using MODIS(Moderate-resolution Imaging Spectroradiometer)remote sensing data,in which the dry edge conditions were determined at the pixel scale based on surface energy balance.The MTVDI was validated by field measurements at 30 sites for 10 d and compared with the Temperature-Vegetation Dryness Index(TVDI).The results showed that the R^(2) for MTVDI and soil moisture obviously improved(0.45 for TVDI,0.69 for MTVDI).As for spatial changes,MTVDI can also better reflect the actual soil moisture condition than TVDI.As a result,MTVDI can be considered an effective method to monitor the spatio-temporal changes in surface soil moisture on a regional scale.
基金funded by the Major Program of National Natural Science Foundation of China(No.41790431)。
文摘Subsurface stormflow is a dominant runoff mechanism in steep humid mountainous areas.An insite measurement of subsurface stormflow suggests that the bedrock surface plays an important role in the runoff generation and routing process,which was rarely adopted in hydrological modelling studies.To improve the runoff simulation performance,the bedrock surface topographic index is introduced,and a modified TOPMODEL based on the bedrock surface topographic index is developed to simulate the runoff.The modified TOPMODEL is applied to the Huangbengliu(HBL),a steep watershed in Gongga Mountain,and proved to be more appropriate for the HBL watershed,especially for peak simulation.The Nash-Sutcliffe model efficiency(NSE)is improved from 0.24 to 0.58 in the calibration period and from 0.40 to 0.62 in the verification period.The result of this study can advance the understanding of the mechanism of flash floods and contribute flood control and disaster prevention in the HBL watershed and similar areas.
基金Under the auspices of National Key Research and Development Project of China (No. 2021YFB3901101)National Natural Science Foundation of China (No. 41971322, 42071336, 42001311, 41730104)+2 种基金Jilin Provincial Science and Technology Development Project (No. 20180519021JH)Youth Innovation Promotion Association of Chinese Academy of Sciences (No. 2020234)China Postdoctoral Science Foundation (No. 2020M681057)。
文摘Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is often difficult to distinguish between algal blooms and aquatic vegetation due to their similar spectral characteristics. In this paper, we used modified vegetation presence frequency index(VPF) based on Moderate-resolution Imaging Spectroradiometer(MODIS) imagery to distinguish algal blooms from aquatic vegetation, and analyzed the spatial and temporal variations of algal blooms and aquatic vegetation from a phenological perspective for five large natural lakes with frequent algal bloom outbreaks in China from 2019 to 2020. We simplified the VPF method to make it with a higher spatial transferability so that it could be applied to other lakes in different climatic zones. Through accuracy validation, we found that the modified VPF method can effectively distinguish between algal blooms and aquatic vegetation, and the results vary from lake to lake. The highest accuracy of 97% was achieved in Hulun Lake, where the frequency of algal outbreaks is low and the extent of aquatic vegetation is stable, while the lowest accuracy of 76% was achieved in Dianchi Lake, which is rainy in summer and the lake is small. Analyses suggests that the time period when algal blooms occur most frequently might not coincide with that when they have the largest area. However, in most cases these two are close in terms of time period. The modified VPF method has a broad scope of application, is easy to implement, and has a high practical value. Furthermore, the method could be established using only a small amount of measured data, which is useful for water quality monitoring on large spatial scales.
基金supported by the National Key Research and Development Program(Grant No.2021YFA0716100)the National Key Research and Development Program of China Project(Grant No.2018YFC0603502)+1 种基金the Henan Youth Science Fund Program(Grant No.212300410105)the provincial key R&D and promotion special project of Henan Province(Grant No.222102320279).
文摘Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysical consistency constraint methods,which are mutually independent.Currently,there is a need for joint inversion methods that can comprehensively consider the structural consistency constraints and petrophysical consistency constraints.This paper develops the structural similarity index(SSIM)as a new structural and petrophysical consistency constraint for the joint inversion of gravity and vertical gradient data.The SSIM constraint is in the form of a fraction,which may have analytical singularities.Therefore,converting the fractional form to the subtractive form can solve the problem of analytic singularity and finally form a modified structural consistency index of the joint inversion,which enhances the stability of the SSIM constraint applied to the joint inversion.Compared to the reconstructed results from the cross-gradient inversion,the proposed method presents good performance and stability.The SSIM algorithm is a new joint inversion method for petrophysical and structural constraints.It can promote the consistency of the recovered models from the distribution and the structure of the physical property values.Then,applications to synthetic data illustrate that the algorithm proposed in this paper can well process the synthetic data and acquire good reconstructed results.
基金the financial support given by the Special Funds for Science and Technology Innovation on Carbon Peak Carbon Neutral of Jiangsu Province,China(BK20220017)the Innovation Development Project of China Meteorological Administration(CXFZ2023J073)the National Key R&D Program of China(2018YFC1506606).
文摘Otindag Sandy Land in China is an important ecological barrier to Beijing;the changes in its ecological quality are major concerns for sustainable development and planning of this area.Based on principal component analysis and path analysis,we first generated a modified remote sensing ecological index(MRSEI)coupled with satellite and ground observational data during 2001–2020 that integrated four local indicators(greenness,wetness,and heatness that reflect vegetation status,water,and heat conditions,respectively,as well as soil erosion).Then,we assessed the ecological quality in Otindag Sandy Land during 2001–2020 based on the MRSEI at different time scales(i.e.,the whole year,growing season,and non-growing season).MRSEI generally increased with an upward rate of 0.006/a during 2001–2020,with clear seasonal and spatial variations.Ecological quality was significantly improved in most regions of Otindag Sandy Land but degraded in the southern part.Regions with ecological degradation expanded to 18.64%of the total area in the non-growing season.The area with the worst grade of MRSEI shrunk by 15.83%of the total area from 2001 to 2020,while the area with the best grade of MRSEI increased by 9.77%of the total area.The temporal heterogeneity of ecological conditions indicated that the improvement process of ecological quality in the growing season may be interrupted or deteriorated in the following non-growing season.The implementation of ecological restoration measures in Otindag Sandy Land should not ignore the seasonal characteristics and spatial heterogeneity of local ecological quality.The results can explore the effectiveness of ecological restoration and provide scientific guides on sustainable development measures for drylands.
基金Supported by the National Basic Research Program of China(973Program)(No.2012CB417402)the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences(No.LTO1510)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA11010102)the National Natural Science Foundation of China(No.41106018)the Funds for Creative Research Groups of China(No.41421005)the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1406401)
文摘To understand the impacts of large-scale circulation during the evolution of E1 Nifio cycle on tropical cyclones (TC) is important and useful for TC forecast. Based on best-track data from the Joint Typhoon Warning Center and reanalysis data from National Centers for Environmental Prediction for the period 1975- 2014, we investigated the influences of two types of E1 Nifio, the eastern Pacific E1 Nifio (EP-E1 Nifio) and central Pacific E1 Nifio (CP-E1 Nifio), on global TC genesis. We also examined how various environmental factors contribute to these influences using a modified genesis potential index (MGPI). The composites reproduced for two types of E1 Nifio, from their developing to decaying phases, were able to qualitatively replicate observed cyclogenesis in several basins except for the Arabian Sea. Certain factors of MGPI with more influence than others in various regions are identified. Over the western North Pacific, five variables were all important in the two E1Nifio types during developing summer (July-August-September) and fall (October- November-December), and decaying spring (April-May-June) and summer. In the eastern Pacific, vertical shear and relative vorticity are the crucial factors for the two types of El Nifio during developing and decaying summers. In the Atlantic, vertical shear, potential intensity and relative humidity are important for the opposite variation of EP- and CP-EI Nifios during decaying summers. In the Southern Hemisphere, the five variables have varying contributions to TC genesis variation during peak season (January-February-March) for the two types of E1 Nifio. In the Bay of Bengal, relative vorticity, humidity and omega may be responsible for clearly reduced TC genesis during developing fall for the two types and slightly suppressed TC cyclogenesis during EP-E1 Nifio decaying spring. In the Arabian Sea, the EP-E1 Nifio generates a slightly positive anomaly of TC genesis during developing falls and decaying springs, but the MGPI failed to capture this variation.
基金Supported by the National Natural Science Foundation of China(61273167)
文摘Complex processes often work with multiple operation regions, it is critical to develop effective monitoring approaches to ensure the safety of chemical processes. In this work, a discriminant local consistency Gaussian mixture model(DLCGMM) for multimode process monitoring is proposed for multimode process monitoring by integrating LCGMM with modified local Fisher discriminant analysis(MLFDA). Different from Fisher discriminant analysis(FDA) that aims to discover the global optimal discriminant directions, MLFDA is capable of uncovering multimodality and local structure of the data by exploiting the posterior probabilities of observations within clusters calculated from the results of LCGMM. This may enable MLFDA to capture more meaningful discriminant information hidden in the high-dimensional multimode observations comparing to FDA. Contrary to most existing multimode process monitoring approaches, DLCGMM performs LCGMM and MFLDA iteratively, and the optimal subspaces with multi-Gaussianity and the optimal discriminant projection vectors are simultaneously achieved in the framework of supervised and unsupervised learning. Furthermore, monitoring statistics are established on each cluster that represents a specific operation condition and two global Bayesian inference-based fault monitoring indexes are established by combining with all the monitoring results of all clusters. The efficiency and effectiveness of the proposed method are evaluated through UCI datasets, a simulated multimode model and the Tennessee Eastman benchmark process.
文摘Let G be simple connected graph with the vertex and edge sets V (G) and E (G), respectively. The Schultz and Modified Schultz indices of a connected graph G are defined as and , where d (u, v) is the distance between vertices u and v?;dv is the degree of vertex v of G. In this paper, computation of the Schultz and Modified Schultz indices of the Jahangir graphs J5,m is proposed.
文摘One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearing characteristics. Viscosity Index (VI) is one approach used widely in the lubricating field to assess the variation of viscosity with temperature. The VI of both mineral and synthetic base oils can be improved by the addition of polymeric viscosity modifiers (VMs). VI improvement by VMs is widely attributed to the polymer coil size expanding with increasing temperature. However, there is very little physical data supporting this generally accepted mechanism. To address this issue, intrinsic viscosity measurements and Small-Angle Neutron Scattering (SANS) have been used to study the variation of polymer coil size with changing temperature and concentration in a selection of solvents. The results will show that coil size expansion with temperature is not necessary to achieve significant elevation of viscosity index.
基金FAPEMIG (PPM X 45-16)CNPqpartially funded by CNPq 308035/2013-5
文摘Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain erosive potential, and precipitation concentration in the Mantaro River Basin, in the Peruvian Andes, which is important for agriculture and energy production in Peru. We assumed the Intergovernmental Panel on Climate Change (IPCC) AIB greenhouse gas emission scenario and simulated the global climate change by the HadCM3 global climate model. Due to the steepness of the mountain slopes and the narrowness of the river valley, this study uses the downscaling of the global model simulations by the regional Eta model down to 2o-km resolution. The downscaling projections show decrease in the monthly precipitation with respect to the baseline period, especially during the rainy season, between February and April, until the end of the 21st century. Meanwhile, a progressive increase in the monthly evaporation from the baseline period is projected. The Modified Fournier Index (MFI) shows a statistically significant downward trend in the Mantaro River Basin, whieh suggests a possible reduction in the rain erosive potential. The Precipitation Concentration Index (PCI) shows a statistically significant increasing trend, which indicates increasingly more irregular temporal distribution of precipitation towards the end of the century. The results of this study allow us to conclude that there should be a gradual increase in water deficit and precipitation concentration. Both changes can be negative for agriculture, power generation, and water supply in the Mantaro River Basin in Peru.
文摘Determination of the work index of Gyel-Buruku columbite ore sample in Plateau state, Nigeria, was investigated. The sample of the columbite ore was sourced from Gyel village in Jos East Local Government Area of Plateau state, Nigeria. The “reference ores (granites)” samples were sourced from Jiche and Gurum villages of Plateau state respectively. The reference ores and columbite ore of known weights were ground and pulverized. 80% passing size for the columbite ore, Jiche and Gurum granites samples was obtained at 100 μm sieve size for the feeds and products respectively. The work indexes of reference ores i.e. Jiche and Gurum granites were used to calculate the work index of the Gyel columbite ore sample. The values of 3.42 kWh/ton and 2.72 kWh/ton were obtained respectively for the two different reference granites ores samples used and 3.07 kWh/ton was calculated as their average and determined as the value of the work index of the Gyel-Bukuru columbite ore sample. This work index value obtained for the Gyel-Buruku columbite ore sample lies favourably within the work indexes of 3.94 - 10.81 kWh/ton for columbite minerals sighted in the literatures.
基金Funded by the National Natural Science Foundation of China(51178348)
文摘A method was developed to make a quantitative analysis of the microstructure of asphalt modified with styrene-butadiene-styrene block(SBS) copolymer. Moreover, both mixed and branched SBS were employed in the preparation of modified asphalt. By sampling specimens from the top, middle, and bottom, a number of microscope slides were made and 400 times micro images were gained. Binarized with the software of MATLAB, the images then went to the process of distribution test, when four typical distributions were employed to investigate the distribution of modifi er spread in asphalt. The distribution characteristic and its parameter were both found. The results show that asphalt phase clearly obeys Poisson distribution, and its parameter, λ, is bond up with the condition SBS performs in. Based on this parameter, indexes can be set up to evaluate the structure of the mixture and its performance as well. Compared with that modifi ed with mixed SBS, the asphalt modifi ed with branched SBS has better performance but worse stability, for it is easier to segregate.
基金Supported by Confederation of Epidemiological Associations registered under Govt of Kerala(Grant No.30-955/2012 CEA)
文摘Objective:To study the differences between the lipid profiles of the subjects whose parents are having known non-modifiable risk factors such as obesity,hypertension(HTN),myocardial infarction and diabetes,and compare them with the lipid profiles of the subjects whose parents are not having those risk factors.Methods:A total of 402 subjects were recruited to this study.A detailed questionnaire which included information on the past medical history,height,weight,blood pressure,physical activity,smoke,alcohol,family history of coronary heart disease,HTN.diabetics and obesity.Basic demographic data and dietary habits were completed by all participants.Blood samples were obtained from all subjects after 14 h.Lipid profiles were analyzed using automated analyzer.The results were analyzed using SPSS software packages.Results:The mean body mass index of the population was well below the cut-off value of obesity(>24.5 kg/m") and high risk of future cardiovascular disorder(CVD) events in this age group.The mean levels of total cholesterol(TC),triglycerides(TG) and TC/high density lipoprotein(HDL) were less than the risk levels indicative of future CVD events according to the ATP Ⅲ cut-off values.However the mean HDL level in our population was slightly greater than the cut-off value while the mean low density lipoprotein level was almost similar to the risk level.Differences were observed when the subjects without history of maternal obesity were compared with subjects with history of maternal obesity.The greater percentage of subjects who are having risk levels of body mass index.TC.low density lipoprotein.TG.and TC/HDI.indicated that maternal obesity contributed to the greater susceptibility of developing CVD risk in their offspring.Conclusions:Advancing age may result in changes that could be atherogenic in the future.Such atherogenic changes have already initialed when the subjects are about 21 years old.The incidence of atherogenic changes is far greater when mothers who are having any of the risk factors such as obesity,diabetes,HTN and myocardial infarction than that fathers who are havine similar risk factors.