According to the current situation and development planning of water resources in Jiangjin District of Three Gorge Reservoir Area at the upper reaches of Yangtze River,by combining with social needs,through the survey...According to the current situation and development planning of water resources in Jiangjin District of Three Gorge Reservoir Area at the upper reaches of Yangtze River,by combining with social needs,through the survey on pollution source and analysis of water quality,based on the Report of Water Function Division of Jiangjin District(2005) ,the adjustment and revision have been conducted on water function divisions,and corresponding protection targets and countermeasures for water resources have been proposed,so that the water function division can comply with the development situation of Jiangjin District,providing a reliable reference for the protection and reasonable utilization of water resources,enhancing the unified and effective supervision of water resources,promoting the sustainable use of water resources in Jiangjin District,and ensuring the sustainable development of regional society and environment.展开更多
Water function classification is to divide the waters in a basin or a region into different water function regions according to the natural features such as water resources condition, physical geographical location, e...Water function classification is to divide the waters in a basin or a region into different water function regions according to the natural features such as water resources condition, physical geographical location, environmental condition, etc. and social features such as the status quo of development and utilization, the requirement of social and economic development on water quantity and quality etc. Water function division has not ever been carried out in China and no ready-made theory and method can be complied with, in the meantime, it is a fundamental work with strong practical function. Therefore, the basic concept and theory foundation and research method are put forward on the base of summary of water resources management and developed and will be perfected in practice process of water function division. The Yangtze function zone covers the Yangtze river basin, the Lancang river basin and the rivers in the western area of the Lancang river in Southwest China. According to the technical outline of national water function division and combined with division practice of the Yangtze function zone, this paper presents the scope determination, procedure and method of water function division.展开更多
The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the...The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the impact of EFPZ on the regional water conservation function,based on land use data from 2005,2008,2010,2015 and 2020,by conducting a counterfactual simulation along with the GeoSOS-FLUS model and the InVEST model.The results demonstrate that the delineation of EFPZ can significantly influence the water conservation.(1)From 2010 to 2020,as the EFPZ was implemented,the water conservation in the study area was increasing year by year,with a growth rate of 0.03×10^(8) m^(3)∙a^(-1).On the other hand,the simulated water conservation capacity without the implementation of EFPZ decreased year by year,with a decrease rate of 0.01×10^(8) m^(3)∙a^(-1).(2)The EFPZ accounts for only 23%of the total area,but the contribution rate of water conservation reaches 80%.The actual values of water conservation and average water yield per unit pixel in the EFPZ show an increasing trend both internally and externally,while the counterfactual simulation values exhibit a decreasing trend.(3)The water conservation is much higher within the EFPZ than without EFPZ.The implementation of EFPZ has a significant effect on the improvement of the water conservation capacity in Maqu EFPZ and Yellow River Source EFPZ.The protection effectiveness should be enhanced in Qilian Mountain EFPZ and afforestation activities need to be carefully considered in Loess Plateau EFPZ.展开更多
The Grain for Green project has had a substantial influence on water conservation in the Huangshui River Basin,China through afforestation and grassland restoration over the past two decades.However,a comprehensive un...The Grain for Green project has had a substantial influence on water conservation in the Huangshui River Basin,China through afforestation and grassland restoration over the past two decades.However,a comprehensive understanding of the spatiotemporal evolution of water conservation function and its driving factors remains incomplete in this basin.In this study,we utilized the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to examine the spatiotemporal evolution of water conservation function in the Huangshui River Basin from 2000 to 2020.Additionally,we employed the random forest model,Pearson correlation analysis,and geographical detector(Geodetector)techniques to investigate the primary factors and factor interactions affecting the spatial differentiation of water conservation function.The findings revealed several key points.First,the high-latitude northern region of the study area experienced a significant increase in water conservation over the 21-a period.Second,the Grain for Green project has played a substantial role in improving water conservation function.Third,precipitation,plant available water content(PAWC),grassland,gross domestic product(GDP),and forest land were primary factors influencing the water conservation function.Finally,the spatial differentiation of water conservation function was determined by the interactions among geographical conditions,climatic factors,vegetation biophysical factors,and socio-economic factors.The findings have significant implications for advancing ecological protection and restoration initiatives,enhancing regional water supply capabilities,and safeguarding ecosystem health and stability in the Huangshui River Basin.展开更多
On basis of test information, the research performed analysis on water production function models of two crops, which indicated that water model of crops in whole growth stage and water model of crops indifferent grow...On basis of test information, the research performed analysis on water production function models of two crops, which indicated that water model of crops in whole growth stage and water model of crops indifferent growth stages have consistency as well as differences, providing references for optimization of irrigation water. Meanwhile, the research analyzed the deficiency of optimization on irrigation water for crops just by Jensen model.展开更多
Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many are...Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many areas such as catalysis, ion separation and adsorption. Owing to the highly tunable compositi on and uniform distribution of metal cations in the brucite-like layers, as well as the facile exchangeability of intercalated anions, LDHs can be modified and functionalized to form various nanostructures/composites through versatile processes such as anion intercalation and exfoliation, decoration of nanoparticles, selfassembly with other two-dimensional (2D) materials, and controlled growth on conductive supports (e.g., nanowire arrays, nano tubes, 3D foams). In this article, we briefly review the recent advances on both the LDH nano structures and functionalized composites toward the applications in energy conversion, especially for water oxidation.展开更多
The Ili River Delta(IRD)is an ecological security barrier for the Lake Balkhash and an important water conservation area in Central Asia.In this study,we selected the IRD as a typical research area,and simulated the w...The Ili River Delta(IRD)is an ecological security barrier for the Lake Balkhash and an important water conservation area in Central Asia.In this study,we selected the IRD as a typical research area,and simulated the water yield and water conservation from 1975 to 2020 using the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.We further analyzed the temporal and spatial variations in the water yield and water conservation in the IRD from 1975 to 2020,and investigated the main driving factors(precipitation,potential evapotranspiration,land use/land cover change,and inflow from the Ili River)of the water conservation variation based on the linear regression,piecewise linear regression,and Pearson's correlation coefficient analyses.The results indicated that from 1975 to 2020,the water yield and water conservation in the IRD showed a decreasing trend,and the spatial distribution pattern was"high in the east and low in the west";overall,the water conservation of all land use types decreased slightly.The water conservation volume of grassland was the most reduced,although the area of grassland increased owing to the increased inflow from the Ili River.At the same time,the increased inflow has led to the expansion of wetland areas,the improvement of vegetation growth,and the increase of regional evapotranspiration,thus resulting in an overall reduction in the water conservation.The water conservation depth and precipitation had similar spatial distribution patterns;the change in climate factors was the main reason for the decline in the water conservation function in the delta.The reservoir in the upper reaches of the IRD regulated runoff into the Lake Balkhash,promoted vegetation restoration,and had a positive effect on the water conservation;however,this positive effect cannot offset the negative effect of enhanced evapotranspiration.These results provide a reference for the rational allocation of water resources and ecosystem protection in the IRD.展开更多
This study is conducted to investigate the function of paddy fields for flood reduction under different water saving irrigation techniques. A daily water balance component data including rainfall, percolation, and ove...This study is conducted to investigate the function of paddy fields for flood reduction under different water saving irrigation techniques. A daily water balance component data including rainfall, percolation, and overflow through the paddy field levee were collected from experimental paddy rice fields during rainy season cultivation. Results show that paddy field was very effective in flood reduction. More than 40% of rainfall could be stored in the paddy fields. However, the effectiveness of paddy fields in flood reduction was highly depends on the WSI technique used. Semi dry cultivation technique was the most effective one in terms of flood reduction. It retained the rainfall up to 55.7% (365 mm) of the total rainfall (636 mm) without reducing the yield. In terms of flood volume reduction, the alternate wetting and drying performed similarly with traditional continuous flooding, i.e., 37.2% and 40.8%, respectively.展开更多
Water conservation is one of the most important ecosystem functions.This study uses the InVEST model to examine the water conservation function of the Qilian Mountain National Park(QMNP),an important water supply area...Water conservation is one of the most important ecosystem functions.This study uses the InVEST model to examine the water conservation function of the Qilian Mountain National Park(QMNP),an important water supply area in northwest China.We analyzed the spatiotemporal water conservation patterns of QMNP from 1988 to 2019.It showed that the water conservation capacity in QMNP has increased over the past 32 years,reaching a peak of 6.495×108 m3 in 2019.The area with an increased water conservation capacity is 12 times larger than the area with a reduced capacity.We also examined how climatic,land-use,vegetation coverage,and topographical factors influence water conservation functions.We found that precipitation is the main climatic factor in water conservation.The water conservation function also varies with land-cover type,with forests having the highest capacity,followed by grasslands.Lastly,topographical factors,including altitude and slope,also shape the spatial patterns of water conservation functions in QMNP.展开更多
AIM: Recently, drinking load tests with water or nutritional beverages have been proposed as diagnostic tools for functional dyspepsia (FD), therefore we sought to reproduce if these tests can discriminate between FD ...AIM: Recently, drinking load tests with water or nutritional beverages have been proposed as diagnostic tools for functional dyspepsia (FD), therefore we sought to reproduce if these tests can discriminate between FD patients and controls in a Mexican population. METHODS: Twenty FD-Rome Ⅱ patients were matched by age and gender with 20 healthy controls. All underwent both drinking tests at a 15 mL/min rate, randomly, 7 d apart. Every 5 min within each test, four symptoms were evaluated (satiety, bloating, nausea and pain) by Likert scales. Maximum tolerated volume (MTV) was defined as the ingested volume when a score of 5 was reached for any symptom or when the test had to be stopped because the patients could not tolerate more volume. Sensitivity and specificity were analyzed. RESULTS: FD patients had higher symptom scores for both tests compared to controls (water: t= 4.1, P= 0.001 <0.01; Nutren(R): t= 5.2, P= 0.001<0.01). The MTV forwater and Nutren(R) were significantly lower in FD (water: 1014±288 vs 1749±275 mL; t = 7.9, P = 0.001<0.01;Nutren(R): 652±168 vs 1278±286 mL; t= 6.7, P = 0.001<0.01). With the volume tolerated by the controls, the percentile 10 was determined as the lower limit fortolerance. Sensitivity and specificity were 0.90, 0.95 for water and 0.95, 0.95 for Nutren(R) tests.CONCLUSION: A drinking test with water or a nutritional beverage can discriminate between FD patients and healthy subjects in Mexico, with high sensitivity and specificity. These tests could be used as objective, noninvasive, and safe diagnostic approaches for FD patients.展开更多
In recent decades, the control of floods is an efficient management practice for the rehabilitation of rangelands in most arid and semiarid areas. To evaluate the benefits, we used the Landscape Function Analysis (LF...In recent decades, the control of floods is an efficient management practice for the rehabilitation of rangelands in most arid and semiarid areas. To evaluate the benefits, we used the Landscape Function Analysis (LFA) method to assess the function of patches and qualitative capability of a rangeland ecosystem in Gareh By- gone region, Fars province, southwestern Iran. Landscape functionality depends on soil, water and nutrient (col- lectively called "resources") conservation and use within a given ecosystem. Many landscapes are naturally het- erogeneous in terms of resource control and possess patches, where resources tend to accumulate, and in- ter-patches. Assessing rangeland health and function of landscape patches in response to environment and man- agement can give rise to correct management decisions for qualitative improvement of the ecosystem. Therefore, our study area was divided into two parts, i.e. water spreading and control parts, and sampling was done using LFA method in each part separately. Structural parameters, including the number, length and width of patches, and the mean length of inter-patches, were determined by the method to characterize the functional status of the monitoring sites. For each patch/inter-patch type identified in the transect organization log, we recorded its soil surface proper- ties classified according to the Soil Surface Assessment Method. The density, canopy cover and composition of plants were then assessed. The results showed that the number of ecological patches and their dimensions were significantly increased in the water spreading site. Soil stability and the values of nutrient cycling indices were in- creased but the infiltration values were decreased in the water spreading site. It could be related to the effect of suspended materials transported by floods to the soils in the study area. The improvement of ecological patches and rangeland ecosystem was achieved where water spreading systems were practiced. Therefore it can be con- cluded that water spreading as a management plan plays an important role in arid land ecosystem functionality.展开更多
For computation of large amplitude motions of ships fastened to a dock, a fast evaluation scheme is implemented for computation of the time-domain Green function for finite water depth. Based on accurate evaluation of...For computation of large amplitude motions of ships fastened to a dock, a fast evaluation scheme is implemented for computation of the time-domain Green function for finite water depth. Based on accurate evaluation of the Green function directly, a fast approximation method for the Green function is developed by use of Chebyshev polynomials. Examinations are carried out of the accuracy of the Green function and its derivatives from the scheme. It is shown that when an appropriate number of polynomial terms are used, very accurate approximation can be obtained.展开更多
In order to develop a sensor for the detection of toxic H_2S molecule,the interactions of C–NT and CSi–NT with H_2S molecule were investigated by density functional theory calculations. The effects of F functionaliz...In order to develop a sensor for the detection of toxic H_2S molecule,the interactions of C–NT and CSi–NT with H_2S molecule were investigated by density functional theory calculations. The effects of F functionalization and water on the adsorption of H_2S gas on C–NT and CSi–NT surfaces were investigated. The studied nanotubes can interact with the H_2S molecule effectively and so adsorptions of H_2S on studied nanotubes are exothermic and possible from the energetic viewpoint. Replacing the C atoms of C–NT with Si atoms may be a good strategy for improving the sensitivity of C–NT towards H_2S. F functionalization and water cause an increase and decrease in the absolute adsorption energy(Ead) values of H_2S on the studied nanotubes,respectively. There are good linearity dependencies between Ead and orbital energy values of studied nanotubes. The Ead and orbital energy values of studied nanotubes can be considered as important parameters to propose suitable nanotubes with increased potential of H_2S adsorption.展开更多
The functional relation between"water vapor chemistry" ion concentration and the "quantum chemistry" bond parameter iswhere IZ /Z is specific electron affinity constant (as hydration force), IZ is ...The functional relation between"water vapor chemistry" ion concentration and the "quantum chemistry" bond parameter iswhere IZ /Z is specific electron affinity constant (as hydration force), IZ is last ionization potential, Z is ion valence, V is ion volume, N is coordination number(as hydration number), C is ion concentration (μg/L) in condensed wahter of water vapor, R is correlation coefficient, S is standard deviation, a and b are constants. The corresponding correlation curve shows that C has positive correlation to Iz/Z and negative correlation to VN.展开更多
Stream and wetland riparian areas are able to sustain a state of resiliency based on the ecosystem’s ability to attain the functions of its ecological potential. This resiliency allows an area to provide and produce ...Stream and wetland riparian areas are able to sustain a state of resiliency based on the ecosystem’s ability to attain the functions of its ecological potential. This resiliency allows an area to provide and produce desired and valued water quality and aquatic habitat ecosystem services. Maintaining healthy aquatic and riparian habitats depends on “management” allowing for, or facilitating natural recovery of riparian functions. Altering grazing management practices in Maggie Creek lead to changes in riparian functionality, water quality, and aquatic habitat. Maggie Creek basin, historically renowned for its fishery, is one of only a few watersheds in Nevada capable of supporting Lahontan Cutthroat Trout (LCT) (Oncorhynchus clarkia ssp. Henshawi) meta-populations. Prior to 1993, the majority of Maggie Creek was grazed by cattle throughout the growing season. Decades of intensive grazing, water development, and road construction degraded aquatic and riparian habitats. By the early 1990’s, a majority of the Maggie Creek watershed was rated as nonfunctional or functional-at-risk condition with unstable banks, channel incision, loss of riparian vegetation, wide shallow channels, excessive erosion and deposition, reduced stream flows, and increased water temperatures. As mitigation for their 1993 South Operations Area Project mine dewatering, Newmont Mining Company, in cooperation with the Elko District Bureau of Land Management (BLM) and the Elko Land and Livestock Company, developed the Maggie Creek Watershed Restoration Project to enhance LCT habitat. The project was developed to enhance 82 miles of stream, 2000 acres of riparian habitat and 40,000 acres of upland watershed primarily through prescriptive livestock management. Beginning in 1994, grazing systems were implemented for portions of the perennial/intermittent streams. This greatly reduced the frequency and duration of hot season grazing on Maggie Creek and its tributaries. The objective of this paper is to compare 1994 and 2006 stream and wetland riparian assessments using proper functioning condition (PFC) protocol and water quality data.展开更多
In this paper, we investigate the selection rule for desalinating seawater using functionalized graphene sheet as a semi-permissible membrane. Both the applied mathematical modeling and MD simulations will be used to ...In this paper, we investigate the selection rule for desalinating seawater using functionalized graphene sheet as a semi-permissible membrane. Both the applied mathematical modeling and MD simulations will be used to determine the acceptance conditions for water molecule or sodium ion permeating into the functionalized graphene. Both the Lennard-Jones potential and Coulomb forces are considered by taking into accounts the major molecular and ionic interactions between molecules, ions and functionalized graphene sheet. The continuous approximation will then be used to coarse grain most significant molecular and ionic interactions so that the multi-body problems could be simplified into several two-body problems and the 3D motions are reduced into degenerated 1D motion. Our mathematical model and simulations show that the negatively charged graphene always accepts sodium ions and water;however the permeability of water molecules and sodium ions becomes very sensitive to the presence of positive charges on the graphene.展开更多
Ten runoff plots with different planting patterns were established for experimental observation in Yangjichong small watershed of Longli County in Karst region of Guizhou Province. Results show that under the same rai...Ten runoff plots with different planting patterns were established for experimental observation in Yangjichong small watershed of Longli County in Karst region of Guizhou Province. Results show that under the same rainfall condition, shrub land, natural grassland and abandoned land presented the best function of soil and water conservation. The function of soil and water conservation was poor for arbor planting pattern, because the shrub layer, herb layer and forest floor were not formed. Because of no-tillage, surface crust and other effects, the function of soil and water conservation in slope farmland was better than that in runoffplots with arbor planting pattern.展开更多
In previous and this studies it appears that the linear and nonlinear wave theory-can not accurately and easily predict the water particle velocities: Therefore, different from the theoretical considerations, in this ...In previous and this studies it appears that the linear and nonlinear wave theory-can not accurately and easily predict the water particle velocities: Therefore, different from the theoretical considerations, in this study we have attempted to determine the transfer function empirically. Laboratory experiments were performed under various wave conditions. The empirical formulas of the transfer function of the wave height, angular frequency and water particle velocity were obtained on the basis of these test data by dimensional analysis and regression analysis. In intermediate and deep water depth conditions, the transfer function was only a function of a nondimensional parameter which is composed of the angular frequency, the depth of the velocity gauge under the still water level, water depth and the acceleration of gravity. Finally, the empirical formulas were compared with experimental data and observational data form present and Cavaleri's (1978) studies. The empirical formulas were found to be in sufficient correltion with these data.展开更多
A water mass in the sea area under investigation is defined as a fuzzy subset in the discourse universe. Possible forms of membership function of water masses in the mixing modified process are discussed with the mixi...A water mass in the sea area under investigation is defined as a fuzzy subset in the discourse universe. Possible forms of membership function of water masses in the mixing modified process are discussed with the mixing theory for conservative concentration of sea water. It may provide bases for making membership functions. Results in this paper may be extended and applied to shallow water. Examples and discussion are given in this paper.展开更多
Based on the linear wave, solitary wave and fifth order stokes wave derived by use of the Unified Variational Principle of Water Gravity Wave (UVPWGW), this paper derives stream function wave theory by using UVPWGW. T...Based on the linear wave, solitary wave and fifth order stokes wave derived by use of the Unified Variational Principle of Water Gravity Wave (UVPWGW), this paper derives stream function wave theory by using UVPWGW. This paper will handle the Kinematic Free Surface Boundary Condition (KFSBC) and Dynamic Free Surface Boundary Condition (DFSBC) directly and give the optimum solution, instead of the conditions Sigma(Q(av) - Q(i))(2) = min, and the related equations of stational condition. When the wave height H, period T and water depth D are given, the original stream function wave will be determined, and can not be adjusted if it does not agree with the real case; in the present method, the adjustment can be done by adding several constraint conditions, for example, the wave profile can be adjusted according to the condition of accurate peak position. The examples given in this paper show that for the original stream function wave, the DFSBC can be fairly well satisfied, but the KFSBC can not; however, the stream function wave derived by UVPWGW is better than the original one in the sense of minimum error squares in the aspect of the level at which KFSBC and DFSBC are satisfied.展开更多
基金Supported by Chongqing City Sponsored Project of 2011 That is"Revision of Water Function Division of Chongqing City" [No. 3 of 2011 of Yu Water Resources]~~
文摘According to the current situation and development planning of water resources in Jiangjin District of Three Gorge Reservoir Area at the upper reaches of Yangtze River,by combining with social needs,through the survey on pollution source and analysis of water quality,based on the Report of Water Function Division of Jiangjin District(2005) ,the adjustment and revision have been conducted on water function divisions,and corresponding protection targets and countermeasures for water resources have been proposed,so that the water function division can comply with the development situation of Jiangjin District,providing a reliable reference for the protection and reasonable utilization of water resources,enhancing the unified and effective supervision of water resources,promoting the sustainable use of water resources in Jiangjin District,and ensuring the sustainable development of regional society and environment.
文摘Water function classification is to divide the waters in a basin or a region into different water function regions according to the natural features such as water resources condition, physical geographical location, environmental condition, etc. and social features such as the status quo of development and utilization, the requirement of social and economic development on water quantity and quality etc. Water function division has not ever been carried out in China and no ready-made theory and method can be complied with, in the meantime, it is a fundamental work with strong practical function. Therefore, the basic concept and theory foundation and research method are put forward on the base of summary of water resources management and developed and will be perfected in practice process of water function division. The Yangtze function zone covers the Yangtze river basin, the Lancang river basin and the rivers in the western area of the Lancang river in Southwest China. According to the technical outline of national water function division and combined with division practice of the Yangtze function zone, this paper presents the scope determination, procedure and method of water function division.
基金funded by the National Science Foundation of China(Grant No.42161043)the improvement plan of scientific research ability in Northwest Normal University(NWNU-LKQN2020-16).
文摘The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the impact of EFPZ on the regional water conservation function,based on land use data from 2005,2008,2010,2015 and 2020,by conducting a counterfactual simulation along with the GeoSOS-FLUS model and the InVEST model.The results demonstrate that the delineation of EFPZ can significantly influence the water conservation.(1)From 2010 to 2020,as the EFPZ was implemented,the water conservation in the study area was increasing year by year,with a growth rate of 0.03×10^(8) m^(3)∙a^(-1).On the other hand,the simulated water conservation capacity without the implementation of EFPZ decreased year by year,with a decrease rate of 0.01×10^(8) m^(3)∙a^(-1).(2)The EFPZ accounts for only 23%of the total area,but the contribution rate of water conservation reaches 80%.The actual values of water conservation and average water yield per unit pixel in the EFPZ show an increasing trend both internally and externally,while the counterfactual simulation values exhibit a decreasing trend.(3)The water conservation is much higher within the EFPZ than without EFPZ.The implementation of EFPZ has a significant effect on the improvement of the water conservation capacity in Maqu EFPZ and Yellow River Source EFPZ.The protection effectiveness should be enhanced in Qilian Mountain EFPZ and afforestation activities need to be carefully considered in Loess Plateau EFPZ.
基金funded by the National Key R&D Program of China(2023YFC3008502)the National Natural Science Foundation of China(52309103)+2 种基金the Major Science and Technology Programs of the Ministry of Water Resources(MWR)(SKS-2022002)the Chengde Applied Technology Research and Development and Sustainable Development Agenda Innovation Demonstration Zone Special Science and Technology Plan Project(202305B009)the Qinghai Province Applied Basic Research Program(2024-ZJ-773).
文摘The Grain for Green project has had a substantial influence on water conservation in the Huangshui River Basin,China through afforestation and grassland restoration over the past two decades.However,a comprehensive understanding of the spatiotemporal evolution of water conservation function and its driving factors remains incomplete in this basin.In this study,we utilized the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to examine the spatiotemporal evolution of water conservation function in the Huangshui River Basin from 2000 to 2020.Additionally,we employed the random forest model,Pearson correlation analysis,and geographical detector(Geodetector)techniques to investigate the primary factors and factor interactions affecting the spatial differentiation of water conservation function.The findings revealed several key points.First,the high-latitude northern region of the study area experienced a significant increase in water conservation over the 21-a period.Second,the Grain for Green project has played a substantial role in improving water conservation function.Third,precipitation,plant available water content(PAWC),grassland,gross domestic product(GDP),and forest land were primary factors influencing the water conservation function.Finally,the spatial differentiation of water conservation function was determined by the interactions among geographical conditions,climatic factors,vegetation biophysical factors,and socio-economic factors.The findings have significant implications for advancing ecological protection and restoration initiatives,enhancing regional water supply capabilities,and safeguarding ecosystem health and stability in the Huangshui River Basin.
文摘On basis of test information, the research performed analysis on water production function models of two crops, which indicated that water model of crops in whole growth stage and water model of crops indifferent growth stages have consistency as well as differences, providing references for optimization of irrigation water. Meanwhile, the research analyzed the deficiency of optimization on irrigation water for crops just by Jensen model.
基金supported by the National Natural Science Foundation of China(Grant Nos.21505050,51672109)the Dispatch of Faculty Abroad of the University of Jinan+2 种基金the Natural Science Foundation of Shandong Province(Grant No.ZR2016FM30)supported in part by the WPI-MANA,Ministry of Education,Culture,Sports,Science and Technology,Japansupport from JSPS KAKENNHI(18H03869)
文摘Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many areas such as catalysis, ion separation and adsorption. Owing to the highly tunable compositi on and uniform distribution of metal cations in the brucite-like layers, as well as the facile exchangeability of intercalated anions, LDHs can be modified and functionalized to form various nanostructures/composites through versatile processes such as anion intercalation and exfoliation, decoration of nanoparticles, selfassembly with other two-dimensional (2D) materials, and controlled growth on conductive supports (e.g., nanowire arrays, nano tubes, 3D foams). In this article, we briefly review the recent advances on both the LDH nano structures and functionalized composites toward the applications in energy conversion, especially for water oxidation.
基金funded by the National Natural Science Foundation of China(42071245)the Xinjiang Uygur Autonomous Region Innovation Environment Construction Special Project&Science and Technology Innovation Base Construction Project(PT2107)+2 种基金the Third Xinjiang Comprehensive Scientific Survey Project Sub-topic(2021xjkk140305)the Tianshan Talent Training Program of Xinjiang Uygur Autonomous Region(2022TSYCLJ0011)the K.C.Wong Education Foundation(GJTD-2020-14).
文摘The Ili River Delta(IRD)is an ecological security barrier for the Lake Balkhash and an important water conservation area in Central Asia.In this study,we selected the IRD as a typical research area,and simulated the water yield and water conservation from 1975 to 2020 using the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.We further analyzed the temporal and spatial variations in the water yield and water conservation in the IRD from 1975 to 2020,and investigated the main driving factors(precipitation,potential evapotranspiration,land use/land cover change,and inflow from the Ili River)of the water conservation variation based on the linear regression,piecewise linear regression,and Pearson's correlation coefficient analyses.The results indicated that from 1975 to 2020,the water yield and water conservation in the IRD showed a decreasing trend,and the spatial distribution pattern was"high in the east and low in the west";overall,the water conservation of all land use types decreased slightly.The water conservation volume of grassland was the most reduced,although the area of grassland increased owing to the increased inflow from the Ili River.At the same time,the increased inflow has led to the expansion of wetland areas,the improvement of vegetation growth,and the increase of regional evapotranspiration,thus resulting in an overall reduction in the water conservation.The water conservation depth and precipitation had similar spatial distribution patterns;the change in climate factors was the main reason for the decline in the water conservation function in the delta.The reservoir in the upper reaches of the IRD regulated runoff into the Lake Balkhash,promoted vegetation restoration,and had a positive effect on the water conservation;however,this positive effect cannot offset the negative effect of enhanced evapotranspiration.These results provide a reference for the rational allocation of water resources and ecosystem protection in the IRD.
文摘This study is conducted to investigate the function of paddy fields for flood reduction under different water saving irrigation techniques. A daily water balance component data including rainfall, percolation, and overflow through the paddy field levee were collected from experimental paddy rice fields during rainy season cultivation. Results show that paddy field was very effective in flood reduction. More than 40% of rainfall could be stored in the paddy fields. However, the effectiveness of paddy fields in flood reduction was highly depends on the WSI technique used. Semi dry cultivation technique was the most effective one in terms of flood reduction. It retained the rainfall up to 55.7% (365 mm) of the total rainfall (636 mm) without reducing the yield. In terms of flood volume reduction, the alternate wetting and drying performed similarly with traditional continuous flooding, i.e., 37.2% and 40.8%, respectively.
基金supported by the National Key Research and Development Program(2019YFC0507402)。
文摘Water conservation is one of the most important ecosystem functions.This study uses the InVEST model to examine the water conservation function of the Qilian Mountain National Park(QMNP),an important water supply area in northwest China.We analyzed the spatiotemporal water conservation patterns of QMNP from 1988 to 2019.It showed that the water conservation capacity in QMNP has increased over the past 32 years,reaching a peak of 6.495×108 m3 in 2019.The area with an increased water conservation capacity is 12 times larger than the area with a reduced capacity.We also examined how climatic,land-use,vegetation coverage,and topographical factors influence water conservation functions.We found that precipitation is the main climatic factor in water conservation.The water conservation function also varies with land-cover type,with forests having the highest capacity,followed by grasslands.Lastly,topographical factors,including altitude and slope,also shape the spatial patterns of water conservation functions in QMNP.
文摘AIM: Recently, drinking load tests with water or nutritional beverages have been proposed as diagnostic tools for functional dyspepsia (FD), therefore we sought to reproduce if these tests can discriminate between FD patients and controls in a Mexican population. METHODS: Twenty FD-Rome Ⅱ patients were matched by age and gender with 20 healthy controls. All underwent both drinking tests at a 15 mL/min rate, randomly, 7 d apart. Every 5 min within each test, four symptoms were evaluated (satiety, bloating, nausea and pain) by Likert scales. Maximum tolerated volume (MTV) was defined as the ingested volume when a score of 5 was reached for any symptom or when the test had to be stopped because the patients could not tolerate more volume. Sensitivity and specificity were analyzed. RESULTS: FD patients had higher symptom scores for both tests compared to controls (water: t= 4.1, P= 0.001 <0.01; Nutren(R): t= 5.2, P= 0.001<0.01). The MTV forwater and Nutren(R) were significantly lower in FD (water: 1014±288 vs 1749±275 mL; t = 7.9, P = 0.001<0.01;Nutren(R): 652±168 vs 1278±286 mL; t= 6.7, P = 0.001<0.01). With the volume tolerated by the controls, the percentile 10 was determined as the lower limit fortolerance. Sensitivity and specificity were 0.90, 0.95 for water and 0.95, 0.95 for Nutren(R) tests.CONCLUSION: A drinking test with water or a nutritional beverage can discriminate between FD patients and healthy subjects in Mexico, with high sensitivity and specificity. These tests could be used as objective, noninvasive, and safe diagnostic approaches for FD patients.
文摘In recent decades, the control of floods is an efficient management practice for the rehabilitation of rangelands in most arid and semiarid areas. To evaluate the benefits, we used the Landscape Function Analysis (LFA) method to assess the function of patches and qualitative capability of a rangeland ecosystem in Gareh By- gone region, Fars province, southwestern Iran. Landscape functionality depends on soil, water and nutrient (col- lectively called "resources") conservation and use within a given ecosystem. Many landscapes are naturally het- erogeneous in terms of resource control and possess patches, where resources tend to accumulate, and in- ter-patches. Assessing rangeland health and function of landscape patches in response to environment and man- agement can give rise to correct management decisions for qualitative improvement of the ecosystem. Therefore, our study area was divided into two parts, i.e. water spreading and control parts, and sampling was done using LFA method in each part separately. Structural parameters, including the number, length and width of patches, and the mean length of inter-patches, were determined by the method to characterize the functional status of the monitoring sites. For each patch/inter-patch type identified in the transect organization log, we recorded its soil surface proper- ties classified according to the Soil Surface Assessment Method. The density, canopy cover and composition of plants were then assessed. The results showed that the number of ecological patches and their dimensions were significantly increased in the water spreading site. Soil stability and the values of nutrient cycling indices were in- creased but the infiltration values were decreased in the water spreading site. It could be related to the effect of suspended materials transported by floods to the soils in the study area. The improvement of ecological patches and rangeland ecosystem was achieved where water spreading systems were practiced. Therefore it can be con- cluded that water spreading as a management plan plays an important role in arid land ecosystem functionality.
文摘For computation of large amplitude motions of ships fastened to a dock, a fast evaluation scheme is implemented for computation of the time-domain Green function for finite water depth. Based on accurate evaluation of the Green function directly, a fast approximation method for the Green function is developed by use of Chebyshev polynomials. Examinations are carried out of the accuracy of the Green function and its derivatives from the scheme. It is shown that when an appropriate number of polynomial terms are used, very accurate approximation can be obtained.
文摘In order to develop a sensor for the detection of toxic H_2S molecule,the interactions of C–NT and CSi–NT with H_2S molecule were investigated by density functional theory calculations. The effects of F functionalization and water on the adsorption of H_2S gas on C–NT and CSi–NT surfaces were investigated. The studied nanotubes can interact with the H_2S molecule effectively and so adsorptions of H_2S on studied nanotubes are exothermic and possible from the energetic viewpoint. Replacing the C atoms of C–NT with Si atoms may be a good strategy for improving the sensitivity of C–NT towards H_2S. F functionalization and water cause an increase and decrease in the absolute adsorption energy(Ead) values of H_2S on the studied nanotubes,respectively. There are good linearity dependencies between Ead and orbital energy values of studied nanotubes. The Ead and orbital energy values of studied nanotubes can be considered as important parameters to propose suitable nanotubes with increased potential of H_2S adsorption.
文摘The functional relation between"water vapor chemistry" ion concentration and the "quantum chemistry" bond parameter iswhere IZ /Z is specific electron affinity constant (as hydration force), IZ is last ionization potential, Z is ion valence, V is ion volume, N is coordination number(as hydration number), C is ion concentration (μg/L) in condensed wahter of water vapor, R is correlation coefficient, S is standard deviation, a and b are constants. The corresponding correlation curve shows that C has positive correlation to Iz/Z and negative correlation to VN.
文摘Stream and wetland riparian areas are able to sustain a state of resiliency based on the ecosystem’s ability to attain the functions of its ecological potential. This resiliency allows an area to provide and produce desired and valued water quality and aquatic habitat ecosystem services. Maintaining healthy aquatic and riparian habitats depends on “management” allowing for, or facilitating natural recovery of riparian functions. Altering grazing management practices in Maggie Creek lead to changes in riparian functionality, water quality, and aquatic habitat. Maggie Creek basin, historically renowned for its fishery, is one of only a few watersheds in Nevada capable of supporting Lahontan Cutthroat Trout (LCT) (Oncorhynchus clarkia ssp. Henshawi) meta-populations. Prior to 1993, the majority of Maggie Creek was grazed by cattle throughout the growing season. Decades of intensive grazing, water development, and road construction degraded aquatic and riparian habitats. By the early 1990’s, a majority of the Maggie Creek watershed was rated as nonfunctional or functional-at-risk condition with unstable banks, channel incision, loss of riparian vegetation, wide shallow channels, excessive erosion and deposition, reduced stream flows, and increased water temperatures. As mitigation for their 1993 South Operations Area Project mine dewatering, Newmont Mining Company, in cooperation with the Elko District Bureau of Land Management (BLM) and the Elko Land and Livestock Company, developed the Maggie Creek Watershed Restoration Project to enhance LCT habitat. The project was developed to enhance 82 miles of stream, 2000 acres of riparian habitat and 40,000 acres of upland watershed primarily through prescriptive livestock management. Beginning in 1994, grazing systems were implemented for portions of the perennial/intermittent streams. This greatly reduced the frequency and duration of hot season grazing on Maggie Creek and its tributaries. The objective of this paper is to compare 1994 and 2006 stream and wetland riparian assessments using proper functioning condition (PFC) protocol and water quality data.
文摘In this paper, we investigate the selection rule for desalinating seawater using functionalized graphene sheet as a semi-permissible membrane. Both the applied mathematical modeling and MD simulations will be used to determine the acceptance conditions for water molecule or sodium ion permeating into the functionalized graphene. Both the Lennard-Jones potential and Coulomb forces are considered by taking into accounts the major molecular and ionic interactions between molecules, ions and functionalized graphene sheet. The continuous approximation will then be used to coarse grain most significant molecular and ionic interactions so that the multi-body problems could be simplified into several two-body problems and the 3D motions are reduced into degenerated 1D motion. Our mathematical model and simulations show that the negatively charged graphene always accepts sodium ions and water;however the permeability of water molecules and sodium ions becomes very sensitive to the presence of positive charges on the graphene.
文摘Ten runoff plots with different planting patterns were established for experimental observation in Yangjichong small watershed of Longli County in Karst region of Guizhou Province. Results show that under the same rainfall condition, shrub land, natural grassland and abandoned land presented the best function of soil and water conservation. The function of soil and water conservation was poor for arbor planting pattern, because the shrub layer, herb layer and forest floor were not formed. Because of no-tillage, surface crust and other effects, the function of soil and water conservation in slope farmland was better than that in runoffplots with arbor planting pattern.
文摘In previous and this studies it appears that the linear and nonlinear wave theory-can not accurately and easily predict the water particle velocities: Therefore, different from the theoretical considerations, in this study we have attempted to determine the transfer function empirically. Laboratory experiments were performed under various wave conditions. The empirical formulas of the transfer function of the wave height, angular frequency and water particle velocity were obtained on the basis of these test data by dimensional analysis and regression analysis. In intermediate and deep water depth conditions, the transfer function was only a function of a nondimensional parameter which is composed of the angular frequency, the depth of the velocity gauge under the still water level, water depth and the acceleration of gravity. Finally, the empirical formulas were compared with experimental data and observational data form present and Cavaleri's (1978) studies. The empirical formulas were found to be in sufficient correltion with these data.
文摘A water mass in the sea area under investigation is defined as a fuzzy subset in the discourse universe. Possible forms of membership function of water masses in the mixing modified process are discussed with the mixing theory for conservative concentration of sea water. It may provide bases for making membership functions. Results in this paper may be extended and applied to shallow water. Examples and discussion are given in this paper.
文摘Based on the linear wave, solitary wave and fifth order stokes wave derived by use of the Unified Variational Principle of Water Gravity Wave (UVPWGW), this paper derives stream function wave theory by using UVPWGW. This paper will handle the Kinematic Free Surface Boundary Condition (KFSBC) and Dynamic Free Surface Boundary Condition (DFSBC) directly and give the optimum solution, instead of the conditions Sigma(Q(av) - Q(i))(2) = min, and the related equations of stational condition. When the wave height H, period T and water depth D are given, the original stream function wave will be determined, and can not be adjusted if it does not agree with the real case; in the present method, the adjustment can be done by adding several constraint conditions, for example, the wave profile can be adjusted according to the condition of accurate peak position. The examples given in this paper show that for the original stream function wave, the DFSBC can be fairly well satisfied, but the KFSBC can not; however, the stream function wave derived by UVPWGW is better than the original one in the sense of minimum error squares in the aspect of the level at which KFSBC and DFSBC are satisfied.