Photocatalytic H_(2) evolution from seawater splitting presents a promising approach to tackle the fossil energy crisis and mitigate carbon emission due to the abundant source of seawater and sunlight on the earth.How...Photocatalytic H_(2) evolution from seawater splitting presents a promising approach to tackle the fossil energy crisis and mitigate carbon emission due to the abundant source of seawater and sunlight on the earth.However,the development of efficient photocatalysts for seawater splitting remains a formidable challenge.Herein,a 2D/2D ZnIn_(2)S_(4)/WO_(3)(ZIS/WO_(3))heterojunction nanostructure is fabricated to efficiently separate the photoinduced carriers by steering electron transfer from the conduction band minimum of WO_(3) to the valence band maximum of ZIS via constructing internal electric field.Subsequently,plasmonic Au nanoparticles(NPs)as a novel photosensitizer and a reduction cocatalyst are anchored on ZIS/WO_(3) surface to further enhance the optical absorption of ZIS/WO_(3) heterojunction and accelerate the catalytic conversion.The obtained Au/ZIS/WO_(3) photocatalyst exhibits an outstanding H_(2) evolution rate of 2610.6 or 3566.3μmol g^(-1)h~(-1)from seawater splitting under visible or full-spectrum light irradiation,respectively.These rates represent an impressive increase of approximately 7.3-and 6,6-fold compared to those of ZIS under the illumination of the same light source.The unique 2D/2D structure,internal electric field,and plasmonic metal modification together boost the photocatalytic H_(2) evolution rate of Au/ZIS/WO_(3),making it even comparable to H_(2) evolution from pure water splitting.The present work sheds light on the development of efficient photocatalysts for seawater splitting.展开更多
We investigate the chiral edge states-induced Josephson current–phase relation in a graphene-based Josephson junction modulated by the off-resonant circularly polarized light and the staggered sublattice potential.By...We investigate the chiral edge states-induced Josephson current–phase relation in a graphene-based Josephson junction modulated by the off-resonant circularly polarized light and the staggered sublattice potential.By solving the Bogoliubov–de Gennes equation,a φ_(0) Josephson junction is induced in the coaction of the off-resonant circularly polarized light and the staggered sublattice potential,which arises from the fact that the center of-mass wave vector of Cooper pair becomes finite and the opposite center of-mass wave vector to compensate is lacking in the nonsuperconducting region.Interestingly,when the direction of polarization of light is changed,-φ_(0) to φ_(0) transition generates,which generalizes the concept of traditional 0–πtransition.Our findings provide a purely optical way to manipulate a phase-controllable Josephson device and guidelines for future experiments to confirm the presence of graphene-based φ_(0)Josephson junction.展开更多
Since its approval by the Food and Drug Administration in 2011,transcatheter aortic valve implantation(TAVI)has rapidly evolved to become the preferred ultimate intervention for high-and intermediate-risk patients wit...Since its approval by the Food and Drug Administration in 2011,transcatheter aortic valve implantation(TAVI)has rapidly evolved to become the preferred ultimate intervention for high-and intermediate-risk patients with severe symptomatic aortic stenosis.[1]This is due to its non-open-heart,minimally invasive and off-pump advantages.[1]Nevertheless,as a result of the frequent frailty and comorbidity profiles of patients undergoing TAVI,such as advanced cardiac dysfunction and extensive coronary artery disease,or technically difficult anatomy for the procedure itself,[2-4]it is common for these patients to experience critical circulatory collapse perioperatively.These factors are linked to elevated mortality rates,necessitating suitable mechanical circulatory support(MCS)to reverse the disastrous situations.[5]展开更多
LaFeO3 perovskite supported Ni and Ni-Fe catalysts were prepared and applied to methanation reaction of syngas. Two preparation methods were employed. One was one-step citrate complexing method, and the other was a tw...LaFeO3 perovskite supported Ni and Ni-Fe catalysts were prepared and applied to methanation reaction of syngas. Two preparation methods were employed. One was one-step citrate complexing method, and the other was a two step method using citrate complexing method to produce LaFeO3 and followed by loading nickel oxide on it with impregnation. The structure evolution of the sample as prepared was investigated by XRD, TPR and TEM techniques. For the former, the chemical composites of the calcined sample are NiO-Fe2O3/LaFe1-xNixO3. After reduction and reaction of CO methanation, its composites convert to Fe-Ni@Ni/LaFeO3-La2O2CO3, in which Fe-Ni@Ni is metal particles in nano-size composed of nickel core and Fe-Ni alloy shell. For the latter, the chemical composites of the calcined sample are NiO/LaFeO3; and after reduction and reaction of CO methanation, its chemical composites change to Ni/LaFeO3. Ni/LaFeO3 catalyst is a little more active, while Fe-Ni@Ni/LaFeO3-La2O2CO3 is much more stable and shows very good resistance to carbon deposition. In this work it is aimed to show that the structure and composites of the catalysts can be tailored using perovskite-type oxide as precursor with different preparing method or preparing condition. Therefore, it is a promising route to prepare supported bi-metal catalysts in nano-size for a lot of metals with desired catalytic performances.展开更多
A K-tier uplink heterogeneous cellular network is modelled and analysed by accounting for both truncated channel inversion power control and biased user association. Each user has a maximum transmit power constraint a...A K-tier uplink heterogeneous cellular network is modelled and analysed by accounting for both truncated channel inversion power control and biased user association. Each user has a maximum transmit power constraint and transmits data when it has sufficient transmit power to perform channel inversion. With biased user association, each user is associated with a base station(BS) that provides the maximum received power weighted by a bias factor, but not their nearest BS. Stochastic geometry is used to evaluate the performances of the proposed system model in terms of the outage probability and ergodic rate for each tier as functions of the biased and power control parameters. Simulations validate our analytical derivations. Numerical results show that there exists a trade-off introduced by the power cut-off threshold and the maximum user transmit power constraint. When the maximum user transmit power becomes a binding constraint, the overall performance is independent of BS densities. In addition, we have shown that it is beneficial for the outage and rate performances by optimizing different network parameters such as the power cut-off threshold as well as the biased factors.展开更多
Background: So far, there have been no measurements confirmed useful in diagnosing acute mountain sickness(AMS). The aim of this study was to determine the role of heart rate(HR) difference(ΔHR) and oxygen saturation...Background: So far, there have been no measurements confirmed useful in diagnosing acute mountain sickness(AMS). The aim of this study was to determine the role of heart rate(HR) difference(ΔHR) and oxygen saturation(Sa O2) as objective risk factors in aiding the diagnosis of AMS.Methods: A total of 1,019 participants were assigned to either the acute exposure group(AEG): from 500 m to 3,700 m by flight within 2.5 hours(n=752); or the pre-acclimatization group(PAG): ascended to 4,400 m from 3,650 m within three hours by car after adapting 33 days at 3,650m(n=267). The questionnaires or measurements of resting Sa O2 and HR were completed between 18 and 24 hours before departure and after arrival.Results: Incidence of AMS was 61.3%(461) in AEG, with 46.1%(347) mild cases and 15.2%(114) severe cases. In PAG, the incidence was 38.9%(104), with 30.7%(82) mild cases and 8.2%(22) severe cases. The AMS subjects showed a significant increase in HR and a decrease in Sa O2 levels compared with the non-AMS subjects in both groups. ΔHR and post-exposure Sa O2 were significantly correlated with the Lake Louise Score(LLS) in both groups. Stepwise logistic regression analysis revealed the ΔHR >25 and Sa O2 <88% in AEG as well as ΔHR >15 and Sa O2 <86% in PAG to be independent risk factors of AMS. Combining these two measurements could specifically indicate participants with AMS, which showed a positive predictive value of 89% and specificity of 97% in AEG as well as 85% and 98% in PAG.Conclusion:ΔHR or Sa O2, as objective measurements, correlate with AMS. Combination of these two measurements may be useful as an additional specific and objective factor to further confirm the diagnosis of AMS.展开更多
Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in s...Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in soil respiration in a plantation of Eucalyptus globulus. We documented a clear seasonal pattern in soil respiration with the highest values (100.9 mg C-CO2 m(-2) h(-1)) recorded in June and the lowest values (28.7 mg C-CO2 m(-2) h(-1)) in January. The variation in soil respiration was closely associated with the dynamics of soil water driven by the drought. Soil respiration was nearly twice as great in the wet seasons as in the dry seasons. Soil water content accounted for 83-91% of variation in soil respiration, while a combined soil water and soil temperature model explained 90-99% of the variation in soil respiration. Soil water had pronounced effects on soil respiration at the moisture threshold of 6-10%. Soil water was strongly related to changes in soil parameters (i.e., bulk density, pH, soil organic carbon, and available nitrogen). These strongly influenced seasonal variation in soil respiration. We found that soil respiration was strongly suppressed by severe drought. Drought resulted in a shortage of soil water which reduced formation of soil organic carbon, impacted soil acid-base properties and soil texture, and affected soil nutrient availability.展开更多
Electrolyte design strategies are closely related to the capacities, cycle life and safety of sodium–ion batteries. In this study, we aimed to optimize electrolyte with the focus on engineering aspects. The basic phy...Electrolyte design strategies are closely related to the capacities, cycle life and safety of sodium–ion batteries. In this study, we aimed to optimize electrolyte with the focus on engineering aspects. The basic physicochemical properties including ionic conductivity, viscosity,wettability and thermochemical stability of the electrolytes using Na PF6 as the solute and the mixed solvent with different components of EMC,DMC or DEC in PC or EC were systematically measured. Ah pouch cell with NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)/hard carbon electrodes was used to evaluate the performance of the prepared electrolytes. By using the Inductive Coupled Plasma Emission Spectrometer(ICP), X-ray photoelectron spectroscopy(XPS), Thermogravimetric-differential scanning calorimetry(TG-DSC) and Accelerating Rate Calorimeter(ARC), we show that an optimized electrolyte can effectively promote the formation of a protective interfacial layer on two electrodes, which not only retards parasitic reactions between the electrodes and electrolyte but also suppresses dissolution of metal ions from the cathode. With an optimized electrolyte, a NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)/hard carbon cell can attain 56.16% capacity retention under the low temperature of -40℃, and can be able to retain 80%capacity retention after more than 2500 cycles while presenting excellent thermal safety.展开更多
Soil fauna can sensitively respond to alterations in soil environment induced by land-use changes.However,little is known about the impact of urban land-use changes on earthworm communities.In this study,three land-us...Soil fauna can sensitively respond to alterations in soil environment induced by land-use changes.However,little is known about the impact of urban land-use changes on earthworm communities.In this study,three land-use types(i.e.,forest,nursery and abandoned lands)were chosen to identify differences in diversity,abundance and biomass of earthworm community in Kunming City.Urban land-use had a pronounced difference in species composition,evenness and diversity of earthworm communities.Forest land had the highest density,biomass and diversity of the earthworm communities.Total abundance was dominated by endogeic species in nursery land(70%)and abandoned land(80%),whereas in the forest land,the earthworm community comprised epigeic,endogeic and anecic species.Temporal changes in earthworm density and biomass were also significantly affected by land-use change.Total density and biomass of earthworms in the forest and nursery lands were highest in September,but highest in the abandoned land in October.The influence of soil physicochemical properties on the earthworm density and biomass also varied with land-use types.Soil temperature significantly affected earthworm density and biomass in the three land-use types.Soil pH was positively correlated with earthworm biomass in the forest land,but negatively associated with earthworm density in the abandoned land.Soil organic matter was positively correlated only with density and biomass of earthworms in the nursery and abandoned lands.Our results suggest that the species composition,abundance and biomass of earthworm communities can be determined by the modification of soil properties associated with urban land-use type.展开更多
基金supported by the National Natural Science Foundation of China(21872104,21501131,21978216 and 22272082)the Natural Science Foundation of Tianjin for Distinguished Young Scholar(20JCJQJC00150)the Analytical&Testing Center of Tiangong University for PL work。
文摘Photocatalytic H_(2) evolution from seawater splitting presents a promising approach to tackle the fossil energy crisis and mitigate carbon emission due to the abundant source of seawater and sunlight on the earth.However,the development of efficient photocatalysts for seawater splitting remains a formidable challenge.Herein,a 2D/2D ZnIn_(2)S_(4)/WO_(3)(ZIS/WO_(3))heterojunction nanostructure is fabricated to efficiently separate the photoinduced carriers by steering electron transfer from the conduction band minimum of WO_(3) to the valence band maximum of ZIS via constructing internal electric field.Subsequently,plasmonic Au nanoparticles(NPs)as a novel photosensitizer and a reduction cocatalyst are anchored on ZIS/WO_(3) surface to further enhance the optical absorption of ZIS/WO_(3) heterojunction and accelerate the catalytic conversion.The obtained Au/ZIS/WO_(3) photocatalyst exhibits an outstanding H_(2) evolution rate of 2610.6 or 3566.3μmol g^(-1)h~(-1)from seawater splitting under visible or full-spectrum light irradiation,respectively.These rates represent an impressive increase of approximately 7.3-and 6,6-fold compared to those of ZIS under the illumination of the same light source.The unique 2D/2D structure,internal electric field,and plasmonic metal modification together boost the photocatalytic H_(2) evolution rate of Au/ZIS/WO_(3),making it even comparable to H_(2) evolution from pure water splitting.The present work sheds light on the development of efficient photocatalysts for seawater splitting.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12104232,11805103,and 11804167)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK20190137 and BK20180739)+2 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.020414380195 and B230201042)the Jit-b Project(Grant No.201831)the Natural Science Fund of Nanjing University of Posts and Telecommunications(Grant No.NY222163)。
文摘We investigate the chiral edge states-induced Josephson current–phase relation in a graphene-based Josephson junction modulated by the off-resonant circularly polarized light and the staggered sublattice potential.By solving the Bogoliubov–de Gennes equation,a φ_(0) Josephson junction is induced in the coaction of the off-resonant circularly polarized light and the staggered sublattice potential,which arises from the fact that the center of-mass wave vector of Cooper pair becomes finite and the opposite center of-mass wave vector to compensate is lacking in the nonsuperconducting region.Interestingly,when the direction of polarization of light is changed,-φ_(0) to φ_(0) transition generates,which generalizes the concept of traditional 0–πtransition.Our findings provide a purely optical way to manipulate a phase-controllable Josephson device and guidelines for future experiments to confirm the presence of graphene-based φ_(0)Josephson junction.
基金supported by the Beijing Hospitals Authority Clinical Medicine Development of Special Funding Support(ZYLX202111,to XTH)Beijing Hospitals Authority“Ascent Plan”(FDL20190601,to XTH)+2 种基金Young Elite Scientists Sponsorship Program by CAST(2022QNRC001,to LSW)National Natural Science Foundation of China(82200433,to LSW)Beijing Hospitals Authority Youth Programme(QML20230602,to LSW).
文摘Since its approval by the Food and Drug Administration in 2011,transcatheter aortic valve implantation(TAVI)has rapidly evolved to become the preferred ultimate intervention for high-and intermediate-risk patients with severe symptomatic aortic stenosis.[1]This is due to its non-open-heart,minimally invasive and off-pump advantages.[1]Nevertheless,as a result of the frequent frailty and comorbidity profiles of patients undergoing TAVI,such as advanced cardiac dysfunction and extensive coronary artery disease,or technically difficult anatomy for the procedure itself,[2-4]it is common for these patients to experience critical circulatory collapse perioperatively.These factors are linked to elevated mortality rates,necessitating suitable mechanical circulatory support(MCS)to reverse the disastrous situations.[5]
基金supported by the Financial support from the NSF of China(21066007)the NSF of Tianjin China(10JCZDJC23800)the NSF of Mongolia China(2009BS0203)
文摘LaFeO3 perovskite supported Ni and Ni-Fe catalysts were prepared and applied to methanation reaction of syngas. Two preparation methods were employed. One was one-step citrate complexing method, and the other was a two step method using citrate complexing method to produce LaFeO3 and followed by loading nickel oxide on it with impregnation. The structure evolution of the sample as prepared was investigated by XRD, TPR and TEM techniques. For the former, the chemical composites of the calcined sample are NiO-Fe2O3/LaFe1-xNixO3. After reduction and reaction of CO methanation, its composites convert to Fe-Ni@Ni/LaFeO3-La2O2CO3, in which Fe-Ni@Ni is metal particles in nano-size composed of nickel core and Fe-Ni alloy shell. For the latter, the chemical composites of the calcined sample are NiO/LaFeO3; and after reduction and reaction of CO methanation, its chemical composites change to Ni/LaFeO3. Ni/LaFeO3 catalyst is a little more active, while Fe-Ni@Ni/LaFeO3-La2O2CO3 is much more stable and shows very good resistance to carbon deposition. In this work it is aimed to show that the structure and composites of the catalysts can be tailored using perovskite-type oxide as precursor with different preparing method or preparing condition. Therefore, it is a promising route to prepare supported bi-metal catalysts in nano-size for a lot of metals with desired catalytic performances.
基金supported by the National Natural Science Foundation of China (61401225, 61571234)the National Science Foundation of Jiangsu Province (BK20140894, BK20140883, BK20160899)+4 种基金the Six Talented Eminence Foundation of Jiangsu Province (XYDXXJS-044)the National Science Foundation of the Higher Education Institutions of Jiangsu Province (14KJD510007, 16KJB510035)the Jiangsu Planned Projects for Postdoctoral Research Funds (1501125B)China Postdoctoral Science Foundation funded project (2015M581844)the Introduction of Talent Scientific Research Fund of Nanjing University of Posts Telecommunications project (NY213104, NY214190)
文摘A K-tier uplink heterogeneous cellular network is modelled and analysed by accounting for both truncated channel inversion power control and biased user association. Each user has a maximum transmit power constraint and transmits data when it has sufficient transmit power to perform channel inversion. With biased user association, each user is associated with a base station(BS) that provides the maximum received power weighted by a bias factor, but not their nearest BS. Stochastic geometry is used to evaluate the performances of the proposed system model in terms of the outage probability and ergodic rate for each tier as functions of the biased and power control parameters. Simulations validate our analytical derivations. Numerical results show that there exists a trade-off introduced by the power cut-off threshold and the maximum user transmit power constraint. When the maximum user transmit power becomes a binding constraint, the overall performance is independent of BS densities. In addition, we have shown that it is beneficial for the outage and rate performances by optimizing different network parameters such as the power cut-off threshold as well as the biased factors.
基金funded by grants from the Special Health Research Project,the Ministry of Health of China (01002012)
文摘Background: So far, there have been no measurements confirmed useful in diagnosing acute mountain sickness(AMS). The aim of this study was to determine the role of heart rate(HR) difference(ΔHR) and oxygen saturation(Sa O2) as objective risk factors in aiding the diagnosis of AMS.Methods: A total of 1,019 participants were assigned to either the acute exposure group(AEG): from 500 m to 3,700 m by flight within 2.5 hours(n=752); or the pre-acclimatization group(PAG): ascended to 4,400 m from 3,650 m within three hours by car after adapting 33 days at 3,650m(n=267). The questionnaires or measurements of resting Sa O2 and HR were completed between 18 and 24 hours before departure and after arrival.Results: Incidence of AMS was 61.3%(461) in AEG, with 46.1%(347) mild cases and 15.2%(114) severe cases. In PAG, the incidence was 38.9%(104), with 30.7%(82) mild cases and 8.2%(22) severe cases. The AMS subjects showed a significant increase in HR and a decrease in Sa O2 levels compared with the non-AMS subjects in both groups. ΔHR and post-exposure Sa O2 were significantly correlated with the Lake Louise Score(LLS) in both groups. Stepwise logistic regression analysis revealed the ΔHR >25 and Sa O2 <88% in AEG as well as ΔHR >15 and Sa O2 <86% in PAG to be independent risk factors of AMS. Combining these two measurements could specifically indicate participants with AMS, which showed a positive predictive value of 89% and specificity of 97% in AEG as well as 85% and 98% in PAG.Conclusion:ΔHR or Sa O2, as objective measurements, correlate with AMS. Combination of these two measurements may be useful as an additional specific and objective factor to further confirm the diagnosis of AMS.
基金supported by National Natural Science Foundation of China(41461052)China 948 Program of State Forestry Administration(2015-4-39)Fund Project to Start Science Research in Southwest Forestry University(111206)
文摘Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in soil respiration in a plantation of Eucalyptus globulus. We documented a clear seasonal pattern in soil respiration with the highest values (100.9 mg C-CO2 m(-2) h(-1)) recorded in June and the lowest values (28.7 mg C-CO2 m(-2) h(-1)) in January. The variation in soil respiration was closely associated with the dynamics of soil water driven by the drought. Soil respiration was nearly twice as great in the wet seasons as in the dry seasons. Soil water content accounted for 83-91% of variation in soil respiration, while a combined soil water and soil temperature model explained 90-99% of the variation in soil respiration. Soil water had pronounced effects on soil respiration at the moisture threshold of 6-10%. Soil water was strongly related to changes in soil parameters (i.e., bulk density, pH, soil organic carbon, and available nitrogen). These strongly influenced seasonal variation in soil respiration. We found that soil respiration was strongly suppressed by severe drought. Drought resulted in a shortage of soil water which reduced formation of soil organic carbon, impacted soil acid-base properties and soil texture, and affected soil nutrient availability.
基金supported by Natural Science Foundation of China,China(21938005,21676165)Science&Technology Commission of Shanghai Municipality,China(19DZ1205500)+1 种基金Zhejiang Key Research and Development Program,China(2020C01128)National Key Research and Development Program,China(2016YFB0901500)。
文摘Electrolyte design strategies are closely related to the capacities, cycle life and safety of sodium–ion batteries. In this study, we aimed to optimize electrolyte with the focus on engineering aspects. The basic physicochemical properties including ionic conductivity, viscosity,wettability and thermochemical stability of the electrolytes using Na PF6 as the solute and the mixed solvent with different components of EMC,DMC or DEC in PC or EC were systematically measured. Ah pouch cell with NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)/hard carbon electrodes was used to evaluate the performance of the prepared electrolytes. By using the Inductive Coupled Plasma Emission Spectrometer(ICP), X-ray photoelectron spectroscopy(XPS), Thermogravimetric-differential scanning calorimetry(TG-DSC) and Accelerating Rate Calorimeter(ARC), we show that an optimized electrolyte can effectively promote the formation of a protective interfacial layer on two electrodes, which not only retards parasitic reactions between the electrodes and electrolyte but also suppresses dissolution of metal ions from the cathode. With an optimized electrolyte, a NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)/hard carbon cell can attain 56.16% capacity retention under the low temperature of -40℃, and can be able to retain 80%capacity retention after more than 2500 cycles while presenting excellent thermal safety.
基金supported by the China 948Program of National Forestry Bureau(2015-4-39)the National Science Foundation of China(No.41461052+1 种基金31660191)Yunnan education department project(2017YJS089)
文摘Soil fauna can sensitively respond to alterations in soil environment induced by land-use changes.However,little is known about the impact of urban land-use changes on earthworm communities.In this study,three land-use types(i.e.,forest,nursery and abandoned lands)were chosen to identify differences in diversity,abundance and biomass of earthworm community in Kunming City.Urban land-use had a pronounced difference in species composition,evenness and diversity of earthworm communities.Forest land had the highest density,biomass and diversity of the earthworm communities.Total abundance was dominated by endogeic species in nursery land(70%)and abandoned land(80%),whereas in the forest land,the earthworm community comprised epigeic,endogeic and anecic species.Temporal changes in earthworm density and biomass were also significantly affected by land-use change.Total density and biomass of earthworms in the forest and nursery lands were highest in September,but highest in the abandoned land in October.The influence of soil physicochemical properties on the earthworm density and biomass also varied with land-use types.Soil temperature significantly affected earthworm density and biomass in the three land-use types.Soil pH was positively correlated with earthworm biomass in the forest land,but negatively associated with earthworm density in the abandoned land.Soil organic matter was positively correlated only with density and biomass of earthworms in the nursery and abandoned lands.Our results suggest that the species composition,abundance and biomass of earthworm communities can be determined by the modification of soil properties associated with urban land-use type.