Nutrient retention capacity by the land/water ecotone soil of Lake Baiyangdian was studied by means of simulation in situ. The results from column experiments suggested that the standard capacity for phosphorus adsorp...Nutrient retention capacity by the land/water ecotone soil of Lake Baiyangdian was studied by means of simulation in situ. The results from column experiments suggested that the standard capacity for phosphorus adsorption be less than P14 mg·kg -1 soil in order to meet the lake water quality regulation (P 0.1 mg·L -1 ). Thus the 9,333 hectares of ecotone around the lake could retain 1,245 tons phosphorus in the upper 50-cm soil without degrading the water quality. The amount was nearly 24 times large as that of taken by annual reed harvesting. The maximum capacity for phosphorus was measured as P 774 mg·kg -1 soil. The isothermal equation of phosphorus was also obtained. It was found that temperature had a significant effect on the transformation of nitrogen, and higher temperature would accelerated the nitrification rate. Nitrogen retention was conducted by the microbial activities in the soil and the uptake through aquatic vegetation. The research will benefit for better utilization of local ecotone and design of the planning project which aims to water eutrophication control.展开更多
Biochar, as a kind of soil amendment, has important effects on soil water retention. In this research, 4 different kinds of biochars were used to investigate their influences on hydraulic properties and water evaporat...Biochar, as a kind of soil amendment, has important effects on soil water retention. In this research, 4 different kinds of biochars were used to investigate their influences on hydraulic properties and water evaporation in a sandy soil from Hebei Province, China. Biochar had strong absorption ability in the sandy soil. The ratio of water content in the biochar to that in the sandy soil was less than the corresponding ratio of porosity. Because of the different hydraulic properties between the sandy soil and the biochar, the saturated hydraulic conductivity of the sandy soil gradually decreased with the increasing biochar addition. The biochar with larger pore volume and average pore diameter had better water retention. More water was retained in the sandy soil when the biochar was added in a single layer, but not when the biochar was uniformly mixed with soil. Particle size of the added biochar had a significant influence on the hydraulic properties of the mixture of sand and biochar. Grinding the biochar into powder destroyed the pore structure, which simultaneously reduced the water absorption ability and hydraulic conductivity of the biochar. For this reason, adding biochar powder to the sandy soil would not decrease the water evaporation loss of the soil itself.展开更多
Laboratory tests under different constraint conditions were carried out to obtain the soil-water retention curves(SWRCs) of highly-compacted confined/unconfined Gaomiaozi(GMZ) bentonite at 20,40 and 80 ℃,respectively...Laboratory tests under different constraint conditions were carried out to obtain the soil-water retention curves(SWRCs) of highly-compacted confined/unconfined Gaomiaozi(GMZ) bentonite at 20,40 and 80 ℃,respectively. The effect of temperature on the soil-water characteristics of the highly-compacted GMZ bentonite was analyzed. The results show that the water retention capacity of the highly-compacted GMZ bentonite decreases as the temperature increases under unconfined and confined conditions. At a certain temperature,the constraint conditions have little influence on the water retention capacity of the compacted bentonite at high suction,but the water retention capacity of the confined specimen is lower than that of the unconfined specimen at low suction. Under unconfined conditions,the hysteretic behaviour of the compacted bentonite decreases with increasing temperature. At high suction(>4 MPa) ,the hysteretic behaviour of the unconfined bentonite tends to increase with the decrease of the suction. In summary,the hysteretic behaviour of the compacted bentonite is not significant.展开更多
Lithium(Li)metal batteries(LMBs)can potentially deliver much higher energy density but remain plagued by uncontrollable Li plating with dendrite growth,unstable interfaces,and highly abundant excess Li(>50 mAh·...Lithium(Li)metal batteries(LMBs)can potentially deliver much higher energy density but remain plagued by uncontrollable Li plating with dendrite growth,unstable interfaces,and highly abundant excess Li(>50 mAh·cm^(-2)).Herein,different from the artificial layer or three-dimensional(3D)matrix host constructions,various dielectric polymers are initially well-comprehensively investigated from experimental characterizations to theoretical simulation to evaluate their functions in modulating Li ion distribution.As a proof of concept,a 3D interwoven high dielectric functional polymer(HDFP)nanofiber network with polar C-F dipole moments electrospun on copper(Cu)foil is designed,realizing uniform and controllable Li deposition capacity up to 5.0 mAh·cm^(-2),thereby enabling stable Li plating/stripping cycling over 1400 h at 1.0 mA·cm^(-2).More importantly,under the highcathode loading(~3.1 mAh·cm^(-2))and only 0.6×excess Li(N/P ratio of 1.6),the full cells retain capacity retention of 97.4%after 200 cycles at 3.36 mA·cm^(-2)and achieve high energy density(297.7 Wh·kg^(-1)at cell-level)under lean electrolyte conditions(15μL),much better than ever-reported literatures.Our work provides a new direction for designing high dielectric polymer coating toward high-retention-rate practical Li full batteries.展开更多
A permanent collapsing gully,locally called Benggang,formed on slopes with deep granite red soil and is a type of unique gully erosion widely prevalent in southern China.Three different soil configurations(SC),ie,red-...A permanent collapsing gully,locally called Benggang,formed on slopes with deep granite red soil and is a type of unique gully erosion widely prevalent in southern China.Three different soil configurations(SC),ie,red-transition-sandy(SC I,the transition is the soil layer between the red soil and the sandy soil layer),transition-sandy(SC II)or sandy(SC III)are usually present in the soil profile of the Benggang slope.However,little attention has been paid to impacts of SCs on the triggering of Benggang erosion.In this study,we aimed to explore the relationships between soil water content(SWC)and triggering of Benggang erosion under different SC conditions.The soil properties of different soil layers were measured and the SWC at depths of 20,40,60,and 80 cm were monitored at 5-min intervals along a typical Benggang(SC I)during 2016-2018.The SWC of Benggang slopes with different SCs were simulated by VADOSE/W model.Results showed that the red soil layer had a higher water retention capacity and shear strength than the sandy soil layer.Even if the SWC is higher(e.g.,0.42 cm^(3)/cm^(3))at red soil layer or transition layer,the corresponding shear strength is greater than that of sandy soil layer with a lower SWC(e.g.,032 cm^(3)/cm^(3)).Relationships between shear strength and SWC of different soil layers indicate that Benggang erosion is triggered by an increase in the SWC in the deep sandy layer.Results also showed that differences exist in the SWC distribution among the different SCs.The SWC is higher in topsoil than in deeper soil in SC I and SC II,while in SC III,the opposite trend is observed.These results revealed that the presence of the red soil or transition layer can reduce the infiltration of rainwater into the deep sandy layer,thus can reduce the possibility of collapse.Our results show that the SC affects the stability of the headwall,and results provide great significances to guide the mitigation of Benggang erosion.展开更多
Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteocond...Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteoconductivity and osteoinductivity is required for clinical therapy.Recently,the three-dimensional(3D)kagome structure has been shown to be advantageous for bone tissue regeneration due to its mechanical properties.In this study,a polycaprolactone(PCL)kagome-structure scaffold containing a hyaluronic acid(HA)-based hydrogel was fabricated using a 3D printing technique.The retention capacity of the hydrogel in the scaffold was assessed in vivo with a rat calvaria subcutaneous model for 3 weeks,and the results were compared with those obtained with conventional 3D-printed PCL grid-structure scaffolds containing HA-based hydrogel and bulk-type HA-based hydrogel.The retained hydrogel in the kagome-structure scaffold was further evaluated by in vivo imaging system analysis.To further reinforce the osteoinductivity of the kagome-structure scaffold,a PCL kagome-structure scaffold with bone morphogenetic protein-2(BMP-2)containing HA hydrogel was fabricated and implanted in a calvarial defect model of rabbits for 16 weeks.The bone regeneration characteristics were evaluated with hematoxylin and eosin(H&E),Masson’s trichrome staining,and micro-CT image analysis.展开更多
Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in induci...Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in inducing loess landslides.This study focuses on three neighboring cities sequentially situated on the Loess Plateau along the direction of aeolian deposition of loess,namely Lanzhou,Dingxi,and Tianshui,which are densely populated and prone to landslide disasters.The variations in hydraulic properties,including water retention capacity and permeability,are investigated through Soil Water Characteristic Curve(SWCC)test and hydraulic conductivity test.The experimental findings revealed that Tianshui loess exhibited the highest water retention capacity,followed by Dingxi loess,while Lanzhou loess demonstrated the lowest water retention capacity.Contrastingly,the results for the saturated permeability coefficient were found to be the opposite:Tianshui loess showed the lowest permeability,whereas Lanzhou loess displayed the highest permeability.These results are supported and analyzed by scanning electron microscopy(SEM)observation.In addition,the water retention capacity is mathematically expressed using the van Genuchten model and extended to predict unsaturated hydraulic properties of loess.The experimental results exhibit a strong accordance with one another and align with the regional distribution patterns of disasters.展开更多
Rapid expansion of cultivated bamboo negatively impacts on biodiversity and soil microbial community.As such,it is important to properly manage and use bamboo to prevent and control such issues.This study focuses on o...Rapid expansion of cultivated bamboo negatively impacts on biodiversity and soil microbial community.As such,it is important to properly manage and use bamboo to prevent and control such issues.This study focuses on optimizing pyrolysis conditions to produce bamboo biochar for agricultural soil amendment,particularly soil potassium(K)and water holding capacity.Bamboo chips were pyrolyzed under nitrogen gas at 400,600,and 800℃ for 1 and 2 h of retention.A total of six biochar products were created:400-1(i.e.,400℃ in 1 h),400-2,600-1,600-2,800-1,and 800-2.The 600℃ bamboo biochar products were observed to have the greatest potential in increasing soil K and water holding capacity.The 600-1 product had the highest potassium content(4.87%),with a water holding capacity of 3.73 g g^(−1),while the 600-2 product had the second-highest potassium content(4.13%)and the highest water holding capacity(4.21 g g^(−1))and cation exchange capacity.The K release in 600℃ products was larger and slower than that of the 400℃ and 800℃ products,respectively.The results also indicated that the physicochemical characteristics of bamboo biochar,such as yield,pH,surface area,water holding capacity,and K content,were significantly impacted by temperature,retention time,or a combination of these parameters.The outcomes from this study are a valuable reference for bamboo biochar production targeting agricultural soil amendment,particularly when it is directed at increasing soil K and water holding capacity.展开更多
文摘Nutrient retention capacity by the land/water ecotone soil of Lake Baiyangdian was studied by means of simulation in situ. The results from column experiments suggested that the standard capacity for phosphorus adsorption be less than P14 mg·kg -1 soil in order to meet the lake water quality regulation (P 0.1 mg·L -1 ). Thus the 9,333 hectares of ecotone around the lake could retain 1,245 tons phosphorus in the upper 50-cm soil without degrading the water quality. The amount was nearly 24 times large as that of taken by annual reed harvesting. The maximum capacity for phosphorus was measured as P 774 mg·kg -1 soil. The isothermal equation of phosphorus was also obtained. It was found that temperature had a significant effect on the transformation of nitrogen, and higher temperature would accelerated the nitrification rate. Nitrogen retention was conducted by the microbial activities in the soil and the uptake through aquatic vegetation. The research will benefit for better utilization of local ecotone and design of the planning project which aims to water eutrophication control.
文摘Biochar, as a kind of soil amendment, has important effects on soil water retention. In this research, 4 different kinds of biochars were used to investigate their influences on hydraulic properties and water evaporation in a sandy soil from Hebei Province, China. Biochar had strong absorption ability in the sandy soil. The ratio of water content in the biochar to that in the sandy soil was less than the corresponding ratio of porosity. Because of the different hydraulic properties between the sandy soil and the biochar, the saturated hydraulic conductivity of the sandy soil gradually decreased with the increasing biochar addition. The biochar with larger pore volume and average pore diameter had better water retention. More water was retained in the sandy soil when the biochar was added in a single layer, but not when the biochar was uniformly mixed with soil. Particle size of the added biochar had a significant influence on the hydraulic properties of the mixture of sand and biochar. Grinding the biochar into powder destroyed the pore structure, which simultaneously reduced the water absorption ability and hydraulic conductivity of the biochar. For this reason, adding biochar powder to the sandy soil would not decrease the water evaporation loss of the soil itself.
基金Projects(40772180, 40572161, 40802064) supported by the National Natural Science Foundation of ChinaProject ([2007]831) supported by Commission of Science, Technology and Industry for National Defense of China+3 种基金Project(07JJ4012) supported by Hunan Provincial Natural Science Foundation of ChinaProject(20080430680) supported by China Postdoctoral Science FoundationProject(08R214155) supported by Shanghai Postdoctoral Scientific Program of ChinaProject(B308) supported by Shanghai Leading Academic Discipline Project of China
文摘Laboratory tests under different constraint conditions were carried out to obtain the soil-water retention curves(SWRCs) of highly-compacted confined/unconfined Gaomiaozi(GMZ) bentonite at 20,40 and 80 ℃,respectively. The effect of temperature on the soil-water characteristics of the highly-compacted GMZ bentonite was analyzed. The results show that the water retention capacity of the highly-compacted GMZ bentonite decreases as the temperature increases under unconfined and confined conditions. At a certain temperature,the constraint conditions have little influence on the water retention capacity of the compacted bentonite at high suction,but the water retention capacity of the confined specimen is lower than that of the unconfined specimen at low suction. Under unconfined conditions,the hysteretic behaviour of the compacted bentonite decreases with increasing temperature. At high suction(>4 MPa) ,the hysteretic behaviour of the unconfined bentonite tends to increase with the decrease of the suction. In summary,the hysteretic behaviour of the compacted bentonite is not significant.
基金This work was financial supported by the National Natural Science Foundation of China(Nos.51877132,52003153,and 22005186)the Program of Shanghai Academic Research Leader(No.21XD1401600).
文摘Lithium(Li)metal batteries(LMBs)can potentially deliver much higher energy density but remain plagued by uncontrollable Li plating with dendrite growth,unstable interfaces,and highly abundant excess Li(>50 mAh·cm^(-2)).Herein,different from the artificial layer or three-dimensional(3D)matrix host constructions,various dielectric polymers are initially well-comprehensively investigated from experimental characterizations to theoretical simulation to evaluate their functions in modulating Li ion distribution.As a proof of concept,a 3D interwoven high dielectric functional polymer(HDFP)nanofiber network with polar C-F dipole moments electrospun on copper(Cu)foil is designed,realizing uniform and controllable Li deposition capacity up to 5.0 mAh·cm^(-2),thereby enabling stable Li plating/stripping cycling over 1400 h at 1.0 mA·cm^(-2).More importantly,under the highcathode loading(~3.1 mAh·cm^(-2))and only 0.6×excess Li(N/P ratio of 1.6),the full cells retain capacity retention of 97.4%after 200 cycles at 3.36 mA·cm^(-2)and achieve high energy density(297.7 Wh·kg^(-1)at cell-level)under lean electrolyte conditions(15μL),much better than ever-reported literatures.Our work provides a new direction for designing high dielectric polymer coating toward high-retention-rate practical Li full batteries.
基金Financial support for this research was provided by the National Natural Science Foundation of China(No.41571258,42007055 and 41630858).
文摘A permanent collapsing gully,locally called Benggang,formed on slopes with deep granite red soil and is a type of unique gully erosion widely prevalent in southern China.Three different soil configurations(SC),ie,red-transition-sandy(SC I,the transition is the soil layer between the red soil and the sandy soil layer),transition-sandy(SC II)or sandy(SC III)are usually present in the soil profile of the Benggang slope.However,little attention has been paid to impacts of SCs on the triggering of Benggang erosion.In this study,we aimed to explore the relationships between soil water content(SWC)and triggering of Benggang erosion under different SC conditions.The soil properties of different soil layers were measured and the SWC at depths of 20,40,60,and 80 cm were monitored at 5-min intervals along a typical Benggang(SC I)during 2016-2018.The SWC of Benggang slopes with different SCs were simulated by VADOSE/W model.Results showed that the red soil layer had a higher water retention capacity and shear strength than the sandy soil layer.Even if the SWC is higher(e.g.,0.42 cm^(3)/cm^(3))at red soil layer or transition layer,the corresponding shear strength is greater than that of sandy soil layer with a lower SWC(e.g.,032 cm^(3)/cm^(3)).Relationships between shear strength and SWC of different soil layers indicate that Benggang erosion is triggered by an increase in the SWC in the deep sandy layer.Results also showed that differences exist in the SWC distribution among the different SCs.The SWC is higher in topsoil than in deeper soil in SC I and SC II,while in SC III,the opposite trend is observed.These results revealed that the presence of the red soil or transition layer can reduce the infiltration of rainwater into the deep sandy layer,thus can reduce the possibility of collapse.Our results show that the SC affects the stability of the headwall,and results provide great significances to guide the mitigation of Benggang erosion.
基金supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute(KHIDI),the Ministry of Health&Welfare,Republic of Korea(Grant Number:HI14C2143)the National Research Foundation of Korea(NRF)grant funded by the Korea government(MIST)(NRF-2021R1A2C2009665)。
文摘Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteoconductivity and osteoinductivity is required for clinical therapy.Recently,the three-dimensional(3D)kagome structure has been shown to be advantageous for bone tissue regeneration due to its mechanical properties.In this study,a polycaprolactone(PCL)kagome-structure scaffold containing a hyaluronic acid(HA)-based hydrogel was fabricated using a 3D printing technique.The retention capacity of the hydrogel in the scaffold was assessed in vivo with a rat calvaria subcutaneous model for 3 weeks,and the results were compared with those obtained with conventional 3D-printed PCL grid-structure scaffolds containing HA-based hydrogel and bulk-type HA-based hydrogel.The retained hydrogel in the kagome-structure scaffold was further evaluated by in vivo imaging system analysis.To further reinforce the osteoinductivity of the kagome-structure scaffold,a PCL kagome-structure scaffold with bone morphogenetic protein-2(BMP-2)containing HA hydrogel was fabricated and implanted in a calvarial defect model of rabbits for 16 weeks.The bone regeneration characteristics were evaluated with hematoxylin and eosin(H&E),Masson’s trichrome staining,and micro-CT image analysis.
基金the financial support for the research presented in this paper from National Natural Science Foundation of China(42201142,42067066,51778590)。
文摘Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in inducing loess landslides.This study focuses on three neighboring cities sequentially situated on the Loess Plateau along the direction of aeolian deposition of loess,namely Lanzhou,Dingxi,and Tianshui,which are densely populated and prone to landslide disasters.The variations in hydraulic properties,including water retention capacity and permeability,are investigated through Soil Water Characteristic Curve(SWCC)test and hydraulic conductivity test.The experimental findings revealed that Tianshui loess exhibited the highest water retention capacity,followed by Dingxi loess,while Lanzhou loess demonstrated the lowest water retention capacity.Contrastingly,the results for the saturated permeability coefficient were found to be the opposite:Tianshui loess showed the lowest permeability,whereas Lanzhou loess displayed the highest permeability.These results are supported and analyzed by scanning electron microscopy(SEM)observation.In addition,the water retention capacity is mathematically expressed using the van Genuchten model and extended to predict unsaturated hydraulic properties of loess.The experimental results exhibit a strong accordance with one another and align with the regional distribution patterns of disasters.
文摘Rapid expansion of cultivated bamboo negatively impacts on biodiversity and soil microbial community.As such,it is important to properly manage and use bamboo to prevent and control such issues.This study focuses on optimizing pyrolysis conditions to produce bamboo biochar for agricultural soil amendment,particularly soil potassium(K)and water holding capacity.Bamboo chips were pyrolyzed under nitrogen gas at 400,600,and 800℃ for 1 and 2 h of retention.A total of six biochar products were created:400-1(i.e.,400℃ in 1 h),400-2,600-1,600-2,800-1,and 800-2.The 600℃ bamboo biochar products were observed to have the greatest potential in increasing soil K and water holding capacity.The 600-1 product had the highest potassium content(4.87%),with a water holding capacity of 3.73 g g^(−1),while the 600-2 product had the second-highest potassium content(4.13%)and the highest water holding capacity(4.21 g g^(−1))and cation exchange capacity.The K release in 600℃ products was larger and slower than that of the 400℃ and 800℃ products,respectively.The results also indicated that the physicochemical characteristics of bamboo biochar,such as yield,pH,surface area,water holding capacity,and K content,were significantly impacted by temperature,retention time,or a combination of these parameters.The outcomes from this study are a valuable reference for bamboo biochar production targeting agricultural soil amendment,particularly when it is directed at increasing soil K and water holding capacity.
