Hyperuricemia,a metabolic disorder related to uric acid metabolism dysregulation,has become a common metabolic disease worldwide,due to changes in lifestyle and dietary structure.In recent years,owing to their high ac...Hyperuricemia,a metabolic disorder related to uric acid metabolism dysregulation,has become a common metabolic disease worldwide,due to changes in lifestyle and dietary structure.In recent years,owing to their high activity and few adverse effects,food-derived active peptides used as functional foods against hyperuricemia have attracted increasing attention.This article aims to focus on the challenge associated with peptide-specific preparation methods development,functional components identification,action mechanism(s)clarification,and bioavailability improvement.The current review proposed recent advances in producing the food-derived peptides with high anti-hyperuricemia activity by protein source screening and matched enzymatic hydrolysis condition adjusting,increased the knowledge about strategies to search antihyperuricemia peptides with definite structure,and emphasized the necessity of combining computer-aided approaches and activity evaluations.In addition,novel action mechanism mediated by gut microbiota was discussed,providing different insights from classical mechanism.Moreover,considering that little attention was paid previously on the structure-activity relationships of anti-hyperuricemia peptides,we collected the sequences from published studies and make a preliminary summary about the structure-activity relationships,which in turn provided guides for enzymatic hydrolysis optimization and bioavailability improvement.Hopefully,this article could promote the development,application and commercialization of food-derived anti-hyperuricemia peptides in the future.展开更多
Groundwater is an important water resource.The total amount of active groundwater in a hydrological cycle is about 3.5 times that of the total amount of surface water.The information in the deep groundwater records th...Groundwater is an important water resource.The total amount of active groundwater in a hydrological cycle is about 3.5 times that of the total amount of surface water.The information in the deep groundwater records the material exchange and dynamics in the earth’s evolution,which is an important aspect of the Deep-Time Digital Earth(DDE)plan.In recent years,scientists have discussed the distribution of transboundary aquifers and the environmental significance of groundwater resources through groundwater databases established by international organizations,such as the Global Groundwater Information System and the chronicles consortium,and national institutes,such as national geological surveys.The application of the groundwater database in the DDE plan,however,has been limited by the management,interactivity,and monitoring method of the groundwater data.The ability to further integrate data that are private and scattered across research institutions and individuals,while establishing an open,unified,and shared groundwater data platform,is essential to enhance our understanding of groundwater,ranging from shallow to deep water,which is a goal of the DDE plan.In this study,we introduced the current situation of groundwater database operations in domestic and international research and provided frontier research with groundwater big data.Considering the related objectives of the DDE plan and the limitations of existing groundwater databases,we proposed an improvement plan and new prospects for applying groundwater databases in the research of the deep earth.展开更多
An Euler wavelets method is proposed to solve a class of nonlinear variable order fractional differential equations in this paper.The properties of Euler wavelets and their operational matrix together with a family of...An Euler wavelets method is proposed to solve a class of nonlinear variable order fractional differential equations in this paper.The properties of Euler wavelets and their operational matrix together with a family of piecewise functions are first presented.Then they are utilized to reduce the problem to the solution of a nonlinear system of algebraic equations.And the convergence of the Euler wavelets basis is given.The method is computationally attractive and some numerical examples are provided to illustrate its high accuracy.展开更多
Reservoir temperature estimation is vitally important for assessing the exploitation potential of a geothermal field.In this study,the concentrations of major chemical constituents in geothermal water sampled from boi...Reservoir temperature estimation is vitally important for assessing the exploitation potential of a geothermal field.In this study,the concentrations of major chemical constituents in geothermal water sampled from boiling and hot springs in the Tengchong hydrothermal area were measured,and quartz and cationic solutes geothermometers were used to calculate subsurface temperatures.Log(Q/K) diagrams and Na-K-Mg triangular diagrams were applied to evaluating the equilibrium status of geothermal water samples with regard to reservoir minerals,and results were used to select suitable geothermometers.The results show that samples RH01,RH03,RH04,RH05,and LL16 were in or very close to full equilibrium with the selected minerals,and therefore a NaK geothermometer is appropriate.A K/Mg geothermometer,however,is applicable to LP08 and PZH18 whose chemical compositions adjusted to the shallow reservoir temperatures during their re-equilibrium processes.In contrast,cationic solute geothermometers are unsuitable for SQ20 and RH07,which are categorized as immature water in the Na-K-Mg diagram;a quartz geothermometer was adopted to evaluate the corresponding subsurface temperatures of these samples.According to the reservoir temperature estimation made in this study,there is at least one high-temperature reservoir below Rehai with a possible temperature range of 210-270 ℃.展开更多
As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this w...As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this work,the triggering voltage of HCS-induced self-heating(SH)degradation is defined in the output characteristics of amorphous indium-galliumzinc oxide(a-IGZO)TFTs,and used to quantitatively evaluate the thermal generation process of channel donor defects.The fluorinated a-IGZO(a-IGZO:F)was adopted to effectively retard the triggering of the self-heating(SH)effect,and was supposed to originate from the less population of initial deep-state defects and a slower rate of thermal defect transition in a-IGZO:F.The proposed scheme noticeably enhances the high-current applications of oxide TFTs.展开更多
A superior carbocatalyst ultrahigh N-doped graphene(NG) was prepared by a novel self-sacrificial templating method of one-step annealing vitamin B_(9).The NG catalyst with pyrolysis temperature of 800℃(abbreviated VB...A superior carbocatalyst ultrahigh N-doped graphene(NG) was prepared by a novel self-sacrificial templating method of one-step annealing vitamin B_(9).The NG catalyst with pyrolysis temperature of 800℃(abbreviated VB_(9)-NG-800) has an ultrahigh nitrogen content of 13.5 wt% and demonstrated the highest activity for the oxidation of bio-based alcohols and terpenes with molecular oxygen without any additives.Systematic characterizations and quantum-chemical calculations further manifested that high contents of graphitic N and pyridinic N species in VB_(9)-NG-800 promoted the generation of·O_(2)^(-)active species from molecular oxygen effortlessly,resulting in excellent catalytic performance for aerobic oxidation.展开更多
Wetland ecosystems are critical habitats for various types of wild lives and are important components of global ecosystem. However, with climate change and human activities, wetlands are facing with degradation. Surfa...Wetland ecosystems are critical habitats for various types of wild lives and are important components of global ecosystem. However, with climate change and human activities, wetlands are facing with degradation. Surface water and groundwater(SW-GW) interactions play an essential role in matter and energy cycling in wetlands, and therefore affect the evolution and health of wetlands. But the role of groundwater in wetland ecosystems has been neglected or simplified. In this paper, we reviewed how surface water interacts with groundwater, and made a systematic summarization of the role of SW-GW interactions(such as maintaining water balance and biological diversity and removing pollution) in wetland ecological functions. We also reviewed the methods to investigate, simulate and quantify SW-GW interactions and related reactions. Finally, we illustrated how climate change and human activities affect SW-GW interactions and therefore affect wetland functions. We highlight the importance of groundwater in wetlands and the urgency to intensify the research in integrated multidisciplinary monitoring and simulation methods, dominant variables and thresholds and integrated water resources management of SW-GW interactions, and further aim to stimulate better protection and restoration of wetlands all over the world.展开更多
Agricultural vehicles are adopted to undertake farming tasks by traversing along crop rows in the field.Working quality depends significantly on the driving skills of the operator.Automatic guidance has been introduce...Agricultural vehicles are adopted to undertake farming tasks by traversing along crop rows in the field.Working quality depends significantly on the driving skills of the operator.Automatic guidance has been introduced into agriculture to achieve high-accuracy path tracking during the last decades,which contributes considerably to straight-line navigation.The objective of this research was to develop an autonomous navigation controller that allowed movement autonomy for various agricultural vehicles.Three wheel-type vehicles were used as the test platform featuring automatic steering,hydrostatic transmission and speed control,which included a rice transplanter,a high-clearance sprayer and a tractor.A dual-antenna RTK-GNSS receiver was attached to the vehicles to provide spatial information on both positioning and heading by using the RTX service from Trimble.A path planning method was proposed to create a straight-line reference path by giving two points,and the target path was determined according to the vehicle initial status and working assignment.Headland turning was comprehensively taken into account by listing different turn patterns in order to realize autonomous navigation at the headland.The navigation controller hardware was fabricated for program execution,data processing and information communication with peripherals.A human-machine interface was designed for the operator to complete basic setting,path planning and navigation control by providing controls.Field experiments were conducted to evaluate the performance and versatility of the newly developed autonomous navigation controller in guiding agricultural vehicles to follow straight paths and turn at the headland.Results showed that an appropriate turn pattern was automatically executed when finishing straight-line navigation.The lateral error in straight-line tracking was no more than 6 cm,6 cm and 5 cm for the rice transplanter,the high-clearance sprayer and the tractor,respectively.And the maximum lateral RMS error was 3.10 cm,4.75 cm,2.21 cm in terms of straight-line tracking,which indicated that the newly developed autonomous navigation controller was versatile and of high robustness in guiding various agricultural vehicles.展开更多
Endemic fluorosis exists in almost all provinces of China.The long-term ingestion of groundwater containing high concentrations of fluoride is one of the main causes of fluoro-sis.We used artificial neural network to ...Endemic fluorosis exists in almost all provinces of China.The long-term ingestion of groundwater containing high concentrations of fluoride is one of the main causes of fluoro-sis.We used artificial neural network to model the relationship between groundwater fluo-ride concentrations from throughout China and environmental variables such as climatic,geological.and soil parameters as proxy predictors.The results show that the accuracy and area under the receiver operating characteristic curve of the model in the test dataset are 80.5%and 0.86%,respectively,and climatic variables are the most effective predictors.Based on the artificial neural network model,a nationwide prediction risk map of fluoride concen-trations exceeding 1.5 mg/L with a 0.5×0.5 arc minutes resolution was generated.The high risk areas are mainly located in western provinces of Xinjiang,Tibet,Qinghai,and Sichuan,and the northern provinces of Inner Mongolia,Hebei and Shandong.The total number of people estimated to be potentially at risk of fluorosis due to the use of untreated high flu-oride groundwater as drinking water is about 89 million,or 6%of the population.The high fluoride groundwater risk map helps the authorities to prioritize areas requiring mitigation measures and thus facilitates the implementation of water improvement and defluorida-tion projects.展开更多
Graphene oxide(GO),a derivative of graphene,is a novel carbon material that has attracted a lot of attention in the field of membrane materials as its ability to achieve layer-by-layer stacking and the formation of na...Graphene oxide(GO),a derivative of graphene,is a novel carbon material that has attracted a lot of attention in the field of membrane materials as its ability to achieve layer-by-layer stacking and the formation of nanochannels between the lamellae makes it excellent for selective separation of substances.In this paper,the separation mechanism of the GO membrane is summarized.According to the different separation substances,the separation mechanism of graphene oxide membrane is reviewed from two aspects of metal ions and organic pollutants.Next,the preparation methods of graphene oxide membranes is introduced,such as spin-coating,vacuum filtration,dip-coating,spraying,and layer-by-layer self-assembly,followed by a review on the structural regulation of GO.Finally,this paper concludes with an overview of the potential development prospects and challenges of GO membranes.展开更多
China is one of the most important producers and suppliers of the chlorobenzenes (CBs), accounting for more than 50% of the world production. Although CBs contamination at the sites of chemical production factories ...China is one of the most important producers and suppliers of the chlorobenzenes (CBs), accounting for more than 50% of the world production. Although CBs contamination at the sites of chemical production factories is well-known, the knowledge on spatial distribution and contaminated degree of CBs are still limited. To better understand the occurrence of CBs, a total of 161 soil/sediment samples were collected from 36 sampling points within a 20 m deep from a site of decommissioned chlorobenzenes-producing factory in Wuhan City, Hubei Province, central China. The results showed that monochlorobenzene (MCB) is the predominant contaminants with the ∑CBs levels ranging from 0.05 to 8 600 mg/kg dry weight (dw) with a mean value of 384 mg/kg dw. The vertical distribution of CBs indicated that CBs may have clearly transported to deeper sections in the subsurface. Statistical analyses showed that there are no good correlations between the ∑CBs concentration with soil organic matter (SOM) content and the moisture content.展开更多
At high tem perature, the oxide redox reactions of ceria can split H2O and CO2 to produce H2 and CO, so porous ceria with high temperature resistance and high specific surface area has an important foreground in clean...At high tem perature, the oxide redox reactions of ceria can split H2O and CO2 to produce H2 and CO, so porous ceria with high temperature resistance and high specific surface area has an important foreground in clean energy applications. In this work, a reticulated porous ceria ceramic material with interconnected porous structure was prepared by the impregnation technique using organic polyurethane sponges as template. The influences of pretreated sponge, dipping time length, pore size and sintering temperature on the porosity and strength of the porous ceria ceramics were system atically studied. With the increasing sintering temperature, the glass phase occurred and led to an increase in strength, but an decrease in porosity. Eventually, we analyzed the relationships betw een porosity and strength of these porous materials, aiming to provide theoretical and practical references for its application in clean-energy field.展开更多
During ancient times,human interest in naturally-occurring gases was religious,while it was scientific in the historical age and industrial in modern times.Gases were also utilized for practical purposes and more than...During ancient times,human interest in naturally-occurring gases was religious,while it was scientific in the historical age and industrial in modern times.Gases were also utilized for practical purposes and more than 3000 years before present day,Chinese populations made use of methane for salt extraction while in the 17th century it was observed that native Americans ignited methane seepages.The development of human thinking on gases followed the fundamental steps that characterized the natural sciences during the 18th century scientific revolution that was based on significant improvements in analytical methods.These improvements are still ongoing while present-day scientific publications evidence the spread of the field of interest and more cooperation with geophysical sciences to solve common interest problems.The existence of proper meetings and dedicated scientific journals confirms that gas geochemistry has ended this pioneering phase to enter a more mature condition.展开更多
The long-term dumping of coal waste piles has caused serious environmental problems. Release of trace elements(including rare earth elements, REEs) from coal spoils gobs was investigated at Yangquan coal mine, Shanx...The long-term dumping of coal waste piles has caused serious environmental problems. Release of trace elements(including rare earth elements, REEs) from coal spoils gobs was investigated at Yangquan coal mine, Shanxi Province, China. X-ray diffraction(XRD) was used to analyze the mineral composition of the coal spoils. The minerals of the coal-spoil samples are mainly kaolinite and quartz, with a minor proportion of pyrite. The batch and column tests were employed to simulate the leaching behavior of trace elements from coal spoils. Elements V, Cr, Zn, As, Pb, and Cd are highly enriched in all coal spoils. The coal spoils also have elevated levels of Ga, Ge, Se, Sn, Hf, and Th. The leachate of coal spoils, fried coal spoils and CSFGM(coal spoils fire gas mineral) samples are acidic, with the p H values ranging between 3.0 and 6.6. The released elements with high concentrations(over 100 μg/L) include Fe, Mn, Co, Ni and Zn, while moderately-released elements are Cu, Se, Mo and As. A high content of heavy metals in batch-test leachate with CSFGM indicates an increased mobility of heavy metals in coal spoil combustion byproduct. Within the first hour washing with the electrolyte solution, a rapid rise of common cations, trace elements, and REEs content, as well as a drop of p H value, in effluent was observed. An increased leaching velocity favors the release of trace elements from coal spoils. In addition, the pulse input of precipitation led to more elements to be released than continuous leaching.展开更多
基金sponsored by the National Natural Science Foundation China(32270115)National Key R&D Program of China(2018YFD0901102)+1 种基金Fundamental Research Funds for the Provincial Universities of Zhejiang(SJLY2021015)K.C.Wong Magna Fund of Ningbo University。
文摘Hyperuricemia,a metabolic disorder related to uric acid metabolism dysregulation,has become a common metabolic disease worldwide,due to changes in lifestyle and dietary structure.In recent years,owing to their high activity and few adverse effects,food-derived active peptides used as functional foods against hyperuricemia have attracted increasing attention.This article aims to focus on the challenge associated with peptide-specific preparation methods development,functional components identification,action mechanism(s)clarification,and bioavailability improvement.The current review proposed recent advances in producing the food-derived peptides with high anti-hyperuricemia activity by protein source screening and matched enzymatic hydrolysis condition adjusting,increased the knowledge about strategies to search antihyperuricemia peptides with definite structure,and emphasized the necessity of combining computer-aided approaches and activity evaluations.In addition,novel action mechanism mediated by gut microbiota was discussed,providing different insights from classical mechanism.Moreover,considering that little attention was paid previously on the structure-activity relationships of anti-hyperuricemia peptides,we collected the sequences from published studies and make a preliminary summary about the structure-activity relationships,which in turn provided guides for enzymatic hydrolysis optimization and bioavailability improvement.Hopefully,this article could promote the development,application and commercialization of food-derived anti-hyperuricemia peptides in the future.
基金supported by the National Natural Science Foundation of China No.41630318Deep-Time Digital Earth(DDE)Plan and Hydrology Team of DDE plan in China University of Geosciences,Wuhan。
文摘Groundwater is an important water resource.The total amount of active groundwater in a hydrological cycle is about 3.5 times that of the total amount of surface water.The information in the deep groundwater records the material exchange and dynamics in the earth’s evolution,which is an important aspect of the Deep-Time Digital Earth(DDE)plan.In recent years,scientists have discussed the distribution of transboundary aquifers and the environmental significance of groundwater resources through groundwater databases established by international organizations,such as the Global Groundwater Information System and the chronicles consortium,and national institutes,such as national geological surveys.The application of the groundwater database in the DDE plan,however,has been limited by the management,interactivity,and monitoring method of the groundwater data.The ability to further integrate data that are private and scattered across research institutions and individuals,while establishing an open,unified,and shared groundwater data platform,is essential to enhance our understanding of groundwater,ranging from shallow to deep water,which is a goal of the DDE plan.In this study,we introduced the current situation of groundwater database operations in domestic and international research and provided frontier research with groundwater big data.Considering the related objectives of the DDE plan and the limitations of existing groundwater databases,we proposed an improvement plan and new prospects for applying groundwater databases in the research of the deep earth.
基金The authors are grateful to the editor,the associate editor and the anonymous reviewers for their constructive and helpful comments.This work was supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY18A010026),the National Natural Science Foundation of China(No.11701304,11526117)Zhejiang Provincial Natural Science Foundation of China(No.LQ16A010006)+1 种基金the Natural Science Foundation of Ningbo City,China(No.2017A610143)the Natural Science Foundation of Ningbo City,China(2018A610195).
文摘An Euler wavelets method is proposed to solve a class of nonlinear variable order fractional differential equations in this paper.The properties of Euler wavelets and their operational matrix together with a family of piecewise functions are first presented.Then they are utilized to reduce the problem to the solution of a nonlinear system of algebraic equations.And the convergence of the Euler wavelets basis is given.The method is computationally attractive and some numerical examples are provided to illustrate its high accuracy.
基金supported by the National Natural Science Foundation of China(No.41120124003)the Ministry of Education of China(111 Project,No.B08030)+1 种基金the Research fund of Bureau of Science and Technology of Qinghai Province(No.2013-G-Q08A)the Fundamental Research Fund for National Universities,China University of Geosciences(Wuhan) (Nos.CUG120505 and CUG120113)
文摘Reservoir temperature estimation is vitally important for assessing the exploitation potential of a geothermal field.In this study,the concentrations of major chemical constituents in geothermal water sampled from boiling and hot springs in the Tengchong hydrothermal area were measured,and quartz and cationic solutes geothermometers were used to calculate subsurface temperatures.Log(Q/K) diagrams and Na-K-Mg triangular diagrams were applied to evaluating the equilibrium status of geothermal water samples with regard to reservoir minerals,and results were used to select suitable geothermometers.The results show that samples RH01,RH03,RH04,RH05,and LL16 were in or very close to full equilibrium with the selected minerals,and therefore a NaK geothermometer is appropriate.A K/Mg geothermometer,however,is applicable to LP08 and PZH18 whose chemical compositions adjusted to the shallow reservoir temperatures during their re-equilibrium processes.In contrast,cationic solute geothermometers are unsuitable for SQ20 and RH07,which are categorized as immature water in the Na-K-Mg diagram;a quartz geothermometer was adopted to evaluate the corresponding subsurface temperatures of these samples.According to the reservoir temperature estimation made in this study,there is at least one high-temperature reservoir below Rehai with a possible temperature range of 210-270 ℃.
基金supported by National Key Research and Development Program under Grant No.2022YFB3607100Shenzhen Research Programs under Grant Nos.JCYJ20200109140601691,JCYJ20190808154803565,SGDX20201103095607022,SGDX20211123145404006,and GXWD20201231165807007-20200807025846001。
文摘As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this work,the triggering voltage of HCS-induced self-heating(SH)degradation is defined in the output characteristics of amorphous indium-galliumzinc oxide(a-IGZO)TFTs,and used to quantitatively evaluate the thermal generation process of channel donor defects.The fluorinated a-IGZO(a-IGZO:F)was adopted to effectively retard the triggering of the self-heating(SH)effect,and was supposed to originate from the less population of initial deep-state defects and a slower rate of thermal defect transition in a-IGZO:F.The proposed scheme noticeably enhances the high-current applications of oxide TFTs.
基金financial support from the National Natural Science Foundations of China (22068013,31570560)21922513 the Natural Science Foundations of Jiangxi Province (20192ACBL20025)the Science and Technology Programs of Jiangxi Province Department of Education (GJJ160272)。
文摘A superior carbocatalyst ultrahigh N-doped graphene(NG) was prepared by a novel self-sacrificial templating method of one-step annealing vitamin B_(9).The NG catalyst with pyrolysis temperature of 800℃(abbreviated VB_(9)-NG-800) has an ultrahigh nitrogen content of 13.5 wt% and demonstrated the highest activity for the oxidation of bio-based alcohols and terpenes with molecular oxygen without any additives.Systematic characterizations and quantum-chemical calculations further manifested that high contents of graphitic N and pyridinic N species in VB_(9)-NG-800 promoted the generation of·O_(2)^(-)active species from molecular oxygen effortlessly,resulting in excellent catalytic performance for aerobic oxidation.
基金the National Natural Science Foundation of China(Nos.41630318,41521001)the Project of China Geological Survey(Nos.121201001000150121,DD20190263,2019040022)the Research Program for Geological Processes,Resources and Environment in the Yangtze River Basin(No.CUGCJ1702)。
文摘Wetland ecosystems are critical habitats for various types of wild lives and are important components of global ecosystem. However, with climate change and human activities, wetlands are facing with degradation. Surface water and groundwater(SW-GW) interactions play an essential role in matter and energy cycling in wetlands, and therefore affect the evolution and health of wetlands. But the role of groundwater in wetland ecosystems has been neglected or simplified. In this paper, we reviewed how surface water interacts with groundwater, and made a systematic summarization of the role of SW-GW interactions(such as maintaining water balance and biological diversity and removing pollution) in wetland ecological functions. We also reviewed the methods to investigate, simulate and quantify SW-GW interactions and related reactions. Finally, we illustrated how climate change and human activities affect SW-GW interactions and therefore affect wetland functions. We highlight the importance of groundwater in wetlands and the urgency to intensify the research in integrated multidisciplinary monitoring and simulation methods, dominant variables and thresholds and integrated water resources management of SW-GW interactions, and further aim to stimulate better protection and restoration of wetlands all over the world.
基金The authors acknowledge that this work was financially supported by National Key Research and Development Program of China Sub-project(2017YFD0700405)Key R&D Project of Shandong Province(2019JZZY010734)+2 种基金National Natural Science Foundation of China(31501230)National Natural Science Foundation of China(51905318)Shandong Province Science and Technology Planning Project of Higher Education(J17KA145).
文摘Agricultural vehicles are adopted to undertake farming tasks by traversing along crop rows in the field.Working quality depends significantly on the driving skills of the operator.Automatic guidance has been introduced into agriculture to achieve high-accuracy path tracking during the last decades,which contributes considerably to straight-line navigation.The objective of this research was to develop an autonomous navigation controller that allowed movement autonomy for various agricultural vehicles.Three wheel-type vehicles were used as the test platform featuring automatic steering,hydrostatic transmission and speed control,which included a rice transplanter,a high-clearance sprayer and a tractor.A dual-antenna RTK-GNSS receiver was attached to the vehicles to provide spatial information on both positioning and heading by using the RTX service from Trimble.A path planning method was proposed to create a straight-line reference path by giving two points,and the target path was determined according to the vehicle initial status and working assignment.Headland turning was comprehensively taken into account by listing different turn patterns in order to realize autonomous navigation at the headland.The navigation controller hardware was fabricated for program execution,data processing and information communication with peripherals.A human-machine interface was designed for the operator to complete basic setting,path planning and navigation control by providing controls.Field experiments were conducted to evaluate the performance and versatility of the newly developed autonomous navigation controller in guiding agricultural vehicles to follow straight paths and turn at the headland.Results showed that an appropriate turn pattern was automatically executed when finishing straight-line navigation.The lateral error in straight-line tracking was no more than 6 cm,6 cm and 5 cm for the rice transplanter,the high-clearance sprayer and the tractor,respectively.And the maximum lateral RMS error was 3.10 cm,4.75 cm,2.21 cm in terms of straight-line tracking,which indicated that the newly developed autonomous navigation controller was versatile and of high robustness in guiding various agricultural vehicles.
基金This work was supported by the National Natural Science Foundation of China(Nos:41772255,41521001).
文摘Endemic fluorosis exists in almost all provinces of China.The long-term ingestion of groundwater containing high concentrations of fluoride is one of the main causes of fluoro-sis.We used artificial neural network to model the relationship between groundwater fluo-ride concentrations from throughout China and environmental variables such as climatic,geological.and soil parameters as proxy predictors.The results show that the accuracy and area under the receiver operating characteristic curve of the model in the test dataset are 80.5%and 0.86%,respectively,and climatic variables are the most effective predictors.Based on the artificial neural network model,a nationwide prediction risk map of fluoride concen-trations exceeding 1.5 mg/L with a 0.5×0.5 arc minutes resolution was generated.The high risk areas are mainly located in western provinces of Xinjiang,Tibet,Qinghai,and Sichuan,and the northern provinces of Inner Mongolia,Hebei and Shandong.The total number of people estimated to be potentially at risk of fluorosis due to the use of untreated high flu-oride groundwater as drinking water is about 89 million,or 6%of the population.The high fluoride groundwater risk map helps the authorities to prioritize areas requiring mitigation measures and thus facilitates the implementation of water improvement and defluorida-tion projects.
基金Y.X.W.,L.J.H.and J.G.T.acknowledge the National Natural Scientific Foundation of China(Nos.51878361 and 52070104)the Natural Scientific Foundation of Shandong Province(No.ZR2019MEM048)+2 种基金the State Key Project of International Cooperation Research(No.2016YFE01108002017YFE0108300)the National Program for Introducing Talents of Discipline to Universities(“111”plan)the 1st Class Discipline Program of Materials Science of Shandong Province,and the DoubleHundred Foreign Expert Program of Shandong Province(2019-2021).
文摘Graphene oxide(GO),a derivative of graphene,is a novel carbon material that has attracted a lot of attention in the field of membrane materials as its ability to achieve layer-by-layer stacking and the formation of nanochannels between the lamellae makes it excellent for selective separation of substances.In this paper,the separation mechanism of the GO membrane is summarized.According to the different separation substances,the separation mechanism of graphene oxide membrane is reviewed from two aspects of metal ions and organic pollutants.Next,the preparation methods of graphene oxide membranes is introduced,such as spin-coating,vacuum filtration,dip-coating,spraying,and layer-by-layer self-assembly,followed by a review on the structural regulation of GO.Finally,this paper concludes with an overview of the potential development prospects and challenges of GO membranes.
基金financial support from the National Key Research and Development Program of China (No. 2017YFD0801005)the National Natural Science Foundation of China (No. 41672246)the Fund for Hubei Technology Innovation (Nos. 2017ACA092, 2016ACA171)
文摘China is one of the most important producers and suppliers of the chlorobenzenes (CBs), accounting for more than 50% of the world production. Although CBs contamination at the sites of chemical production factories is well-known, the knowledge on spatial distribution and contaminated degree of CBs are still limited. To better understand the occurrence of CBs, a total of 161 soil/sediment samples were collected from 36 sampling points within a 20 m deep from a site of decommissioned chlorobenzenes-producing factory in Wuhan City, Hubei Province, central China. The results showed that monochlorobenzene (MCB) is the predominant contaminants with the ∑CBs levels ranging from 0.05 to 8 600 mg/kg dry weight (dw) with a mean value of 384 mg/kg dw. The vertical distribution of CBs indicated that CBs may have clearly transported to deeper sections in the subsurface. Statistical analyses showed that there are no good correlations between the ∑CBs concentration with soil organic matter (SOM) content and the moisture content.
基金financial supports from the fund of the State Key Laboratory of Solidification Processing in NWPU (SKLSP201704)
文摘At high tem perature, the oxide redox reactions of ceria can split H2O and CO2 to produce H2 and CO, so porous ceria with high temperature resistance and high specific surface area has an important foreground in clean energy applications. In this work, a reticulated porous ceria ceramic material with interconnected porous structure was prepared by the impregnation technique using organic polyurethane sponges as template. The influences of pretreated sponge, dipping time length, pore size and sintering temperature on the porosity and strength of the porous ceria ceramics were system atically studied. With the increasing sintering temperature, the glass phase occurred and led to an increase in strength, but an decrease in porosity. Eventually, we analyzed the relationships betw een porosity and strength of these porous materials, aiming to provide theoretical and practical references for its application in clean-energy field.
基金supported partially by the National Science and Technology Major Project of the Ministry of Science and Technology of China(Nos.2021YFA0719003,2019YFA0708501)funds from Chinese Academy of Sciences as a visiting professorship for senior international scientists(No.2018VMA0007)。
文摘During ancient times,human interest in naturally-occurring gases was religious,while it was scientific in the historical age and industrial in modern times.Gases were also utilized for practical purposes and more than 3000 years before present day,Chinese populations made use of methane for salt extraction while in the 17th century it was observed that native Americans ignited methane seepages.The development of human thinking on gases followed the fundamental steps that characterized the natural sciences during the 18th century scientific revolution that was based on significant improvements in analytical methods.These improvements are still ongoing while present-day scientific publications evidence the spread of the field of interest and more cooperation with geophysical sciences to solve common interest problems.The existence of proper meetings and dedicated scientific journals confirms that gas geochemistry has ended this pioneering phase to enter a more mature condition.
基金financially supported by the National Natural Science Foundation of China(Nos.41120124003 and 41372251)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20130145120014)+1 种基金the Natural Science Foundation of Hubei Province,China(No.2013CFB41)the Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology)(No.SKLGP2012K022)
文摘The long-term dumping of coal waste piles has caused serious environmental problems. Release of trace elements(including rare earth elements, REEs) from coal spoils gobs was investigated at Yangquan coal mine, Shanxi Province, China. X-ray diffraction(XRD) was used to analyze the mineral composition of the coal spoils. The minerals of the coal-spoil samples are mainly kaolinite and quartz, with a minor proportion of pyrite. The batch and column tests were employed to simulate the leaching behavior of trace elements from coal spoils. Elements V, Cr, Zn, As, Pb, and Cd are highly enriched in all coal spoils. The coal spoils also have elevated levels of Ga, Ge, Se, Sn, Hf, and Th. The leachate of coal spoils, fried coal spoils and CSFGM(coal spoils fire gas mineral) samples are acidic, with the p H values ranging between 3.0 and 6.6. The released elements with high concentrations(over 100 μg/L) include Fe, Mn, Co, Ni and Zn, while moderately-released elements are Cu, Se, Mo and As. A high content of heavy metals in batch-test leachate with CSFGM indicates an increased mobility of heavy metals in coal spoil combustion byproduct. Within the first hour washing with the electrolyte solution, a rapid rise of common cations, trace elements, and REEs content, as well as a drop of p H value, in effluent was observed. An increased leaching velocity favors the release of trace elements from coal spoils. In addition, the pulse input of precipitation led to more elements to be released than continuous leaching.