Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breedin...Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG.展开更多
As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous ...As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.展开更多
There are five most widely used contact angle schemes in the pseudopotential lattice Boltzmann(LB)model for simulating the wetting phenomenon:The pseudopotential-based scheme(PB scheme),the improved virtualdensity sch...There are five most widely used contact angle schemes in the pseudopotential lattice Boltzmann(LB)model for simulating the wetting phenomenon:The pseudopotential-based scheme(PB scheme),the improved virtualdensity scheme(IVD scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the fluid layer density above the wall(MPB-C scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the weighted average density of surrounding fluid nodes(MPB-W scheme)and the geometric formulation scheme(GF scheme).But the numerical stability and accuracy of the schemes for wetting simulation remain unclear in the past.In this paper,the numerical stability and accuracy of these schemes are clarified for the first time,by applying the five widely used contact angle schemes to simulate a two-dimensional(2D)sessile droplet on wall and capillary imbibition in a 2D channel as the examples of static wetting and dynamic wetting simulations respectively.(i)It is shown that the simulated contact angles by the GF scheme are consistent at different density ratios for the same prescribed contact angle,but the simulated contact angles by the PB scheme,IVD scheme,MPB-C scheme and MPB-W scheme change with density ratios for the same fluid-solid interaction strength.The PB scheme is found to be the most unstable scheme for simulating static wetting at increased density ratios.(ii)Although the spurious velocity increases with the increased liquid/vapor density ratio for all the contact angle schemes,the magnitude of the spurious velocity in the PB scheme,IVD scheme and GF scheme are smaller than that in the MPB-C scheme and MPB-W scheme.(iii)The fluid density variation near the wall in the PB scheme is the most significant,and the variation can be diminished in the IVD scheme,MPB-C scheme andMPBWscheme.The variation totally disappeared in the GF scheme.(iv)For the simulation of capillary imbibition,the MPB-C scheme,MPB-Wscheme and GF scheme simulate the dynamics of the liquid-vapor interface well,with the GF scheme being the most accurate.The accuracy of the IVD scheme is low at a small contact angle(44 degrees)but gets high at a large contact angle(60 degrees).However,the PB scheme is the most inaccurate in simulating the dynamics of the liquid-vapor interface.As a whole,it is most suggested to apply the GF scheme to simulate static wetting or dynamic wetting,while it is the least suggested to use the PB scheme to simulate static wetting or dynamic wetting.展开更多
The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and bounda...The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and boundary conditions individually or collectively influence the hydraulic and volume change behavior of compacted highly expansive soils.The cyclic wetting and drying(CWD)process was applied for two boundary conditions,i.e.constant stress(CS)and constant volume(CV),and for a wide range of axial stress states.The adopted CWD process affected the hydraulic and volume change behaviors of expansive soils,with the first cycle of wetting and drying being the most effective.The CWD process under CS conditions resulted in shrinkage accumulation and reduction in saturated hydraulic conductivity(k sat).On the other hand,CWD under CV conditions caused a reduction of swell pressure while has almost no impact on k sat.An elastic response to CWD was achieved after the third cycle for saturated hydraulic conductivity(k sat),the third to fourth cycle for the volume change potential under the CV conditions,and the fourth to fifth cycle for the volume change potential under the CS conditions.Finally,both swell pressure(s s)and saturated hydraulic conductivity(k sat)are not fundamental parameters of the expansive soil but rather depend on stress,boundary and wetting conditions.展开更多
Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was propo...Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa.展开更多
Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of ...Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of great significance for interpretation of soil macro hydro-mechanical behavior.In this review paper,methods that are commonly used to study soil microstructure are summarized.Among them are scanning electron microscope(SEM),environmental SEM(ESEM),mercury intrusion porosimetry(MIP)and computed tomography(CT)technology.Moreover,progress in research on the soil microstructure evolution during drying,wetting and wetting/drying cycles is summarized based on reviews of a large body of research papers published in the past several decades.Soils compacted on the wet side of op-timum water content generally have a matrix-type structure with a monomodal pore size distribution(PSD),whereas soils compacted on the dry side of optimum water content display an aggregate structure that exhibits bimodal PSD.During drying,decrease in soil volume is mainly caused by the shrinkage of inter-aggregate pores.During wetting,both the intra-and inter-aggregate pores increase gradually in number and sizes.Changes in the characteristics of the soil pore structure significantly depend on stress state as the soil is subjected to wetting.During wetting/drying cycles,soil structural change is not completely reversible,and the generated cumulative swelling/shrinkage deformation mainly derives from macro-pores.Furthermore,based on this analysis and identified research needs,some important areas of research focus are proposed for future work.These areas include innovative methods of sample preparation,new observation techniques,fast quantitative analysis of soil structure,integration of microstructural parameters into macro-mechanical models,and soil microstructure evolution charac-teristics under multi-field coupled conditions.展开更多
MXenes are a class of 2D nanomaterials with exceptional tailormade properties such as mechano-ceramic nature,rich chemistry,and hydrophilicity,to name a few.However,one of the most challenging issues in any composite/...MXenes are a class of 2D nanomaterials with exceptional tailormade properties such as mechano-ceramic nature,rich chemistry,and hydrophilicity,to name a few.However,one of the most challenging issues in any composite/hybrid system is the interfacial wetting.Having a superior integrity of a given composite system is a direct consequence of the proper wettability.While wetting is a fundamental feature,dictating many physical and chemical attributes,most of the common nanomaterials possesses poor affinity due to hydrophobic nature,making them hard to be easily dispersed in a given composite.Thanks to low contact angle,MXenes can offer themselves as an ideal candidate for manufacturing different nano-hybrid structures.Herein this review,it is aimed to particularly study the wettability of MXenes.In terms of the layout of the present study,MXenes are first briefly introduced,and then,the wettability phenomenon is discussed in detail.Upon reviewing the sporadic research efforts conducted to date,a particular attention is paid on the current challenges and research pitfalls to light up the future perspectives.It is strongly believed that taking the advantage of MXene’s rich hydrophilic surface may have a revolutionizing role in the fabrication of advanced materials with exceptional features.展开更多
Surface tension plays a central role in the mechanical behavior of soft materials such as gels.Elastocapillary deformation of elastic graded substrates is ubiquitous in soft materials.In this work,the effect of a part...Surface tension plays a central role in the mechanical behavior of soft materials such as gels.Elastocapillary deformation of elastic graded substrates is ubiquitous in soft materials.In this work,the effect of a partially wetting sessile liquid droplet on the elastocapillary deformation of a soft elastic graded substrate is studied.The modulus is assumed to have an exponential form along the thickness direction.By applying the Fourier transformation,a mixed boundary-value problem is reduced into a dual integral equation.The numerical results show that the surface displacement is strongly affected by the inhomogeneity of the material.The study of the wetting properties of gel substrates is essential for both understanding the wetting phenomena of gels and developing gels for applications as soft actuators and sensors that can be used in wearable electronics and soft robotics.展开更多
Since the 1990s,the Qinghai–Tibetan Plateau(QTP)has experienced a strikingly warming and wetter climate that alters the thermal and hydrological properties of frozen ground.A positive correlation between the warming ...Since the 1990s,the Qinghai–Tibetan Plateau(QTP)has experienced a strikingly warming and wetter climate that alters the thermal and hydrological properties of frozen ground.A positive correlation between the warming and thermal degradation in permafrost or seasonally frozen ground(SFG)has long been recognized.Still,a predictive relationship between historical wetting under warming climate conditions and frozen ground has not yet been well demonstrated,despite the expectation that it will become even more important because precipitation over the QTP has been projected to increase continuously in the near future.This study investigates the response of the thermal regime to historical wetting in both permafrost and SFG areas and examines their relationships separately using the Community Land Surface Model version 4.5.Results show that wetting before the 1990s across the QTP mainly cooled the permafrost body in the arid and semiarid zones,with significant correlation coefficients of 0.60 and 0.48,respectively.Precipitation increased continually at the rate of 6.16 mm decade–1 in the arid zone after the 1990s but had a contrasting warming effect on permafrost through a significant shortening of the thawing duration within the active layer.However,diminished rainfall in the humid zone after the 1990s also significantly extended the thawing duration of SFG.The relationship between the ground thawing index and precipitation was significantly negatively correlated(−0.75).The dual effects of wetting on the thermal dynamics of the QTP are becoming critical because of the projected increases in future precipitation.展开更多
Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectificatio...Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectification phenomenon in an asymmetric solid–liquid–solid sandwiched system with a nano-structured interface.By using the non-equilibrium molecular dynamics simulations,the thermal transport through the solid–liquid–solid system is examined,and the thermal rectification phenomenon can be observed.It is revealed that the thermal rectification effect can be attributed to the significant difference in the interfacial thermal resistance between Cassie and Wenzel states when reversing the temperature bias.In addition,effects of the liquid density,solid–liquid bonding strength and nanostructure size on the thermal rectification are examined.The findings may provide a new way for designs of certain thermal devices.展开更多
Loess is prone to collapse upon wetting due to its open metastable structure,which poses a considerable threat to the environment,construction processes and human life.In this study,double oedometer tests and scanning...Loess is prone to collapse upon wetting due to its open metastable structure,which poses a considerable threat to the environment,construction processes and human life.In this study,double oedometer tests and scanning electron microscopy and mercury intrusion porosimetry analyses were conducted on loess from Yan’an to study the macroscopic and microscopic characteristics of loess wetting deformation and the underlying mechanism.The wetting collapse of loess under loading depends on the changes in different microstructure levels and elements.This collapse chain reaction is manifested by the dissipation,scattering and recombination of the cementation,deformation and reorganization of the particles,blocking of the pore channels,decrease in the dominant size and volume of unstable macropores(>14μm)and abundant mesopores(2.5-14μm),increase in the volume of small pores(0.05–2.5μm),and volume contraction at the macroscale.This process is dependent on the initial water content,stress level and wetting degree.These findings can facilitate collapsible loess hazard prevention and geological engineering construction.展开更多
This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency(WUE) under alternate wetting and drying(AWD) irrigation than check...This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency(WUE) under alternate wetting and drying(AWD) irrigation than check rice. Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered(WW), moderate water deficit(MWD) and severe water deficit(SWD). Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying(AWMD), alternate wetting and severe drying(AWSD) and conventional irrigation(CI). Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice. Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD. Compared with CI, AWMD increased, whereas AWSD decreased grain yield, with more increase or less decrease for super rice than for check rice. Both MWD and SWD treatments and either AWMD or AWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice. The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.展开更多
Wetting and spreading processes which involve surfactant solutions are widely used in numerous industrial and practicalapplications nowadays.The performance of different non-ionic surfactants may vary significantly an...Wetting and spreading processes which involve surfactant solutions are widely used in numerous industrial and practicalapplications nowadays.The performance of different non-ionic surfactants may vary significantly and so far superspreadersolutions show the most promising spreading ability.The addition of trisiloxane surfactants to water was proven to enhancewetting,even on hydrophobic surfaces,on which conventional surfactants seem to have little or no effect.Although theseextraordinary surfactants have been extensively studied over recent years,complete understanding of their underlying mechanismsand a suitable mathematical model are still lacking.Here we present a possible explanation for the impressive performanceof trisiloxane,which is compared to wetting enhancement of a conventional surfactant.Additionally,we will explain whythe hydrophobicity of the surface is a crucial factor for the spreading phenomenon.Light will be also shed on the effect of the pHof the solution to which surfactants are added.Finally,we will investigate long-term effects of the water environment on trisiloxanewetting ability and discuss if ageing may significantly affect their performance.展开更多
Natural surfaces with super hydrophobic properties often have micro or hierarchical structures.In this paper, the wettingbehaviours of a single droplet on biomimetic micro structured surfaces with different roughness ...Natural surfaces with super hydrophobic properties often have micro or hierarchical structures.In this paper, the wettingbehaviours of a single droplet on biomimetic micro structured surfaces with different roughness parameters are investigated.Atheoretical model is proposed to study wetting transitions.The results of theoretical analysis are compared with those of experimentindicating that the proposed model can effectively predict the wetting transition.Furthermore, a numerical simulationbased on the meso scale Lattice Boltzmann Method （LBM） is performed to study dynamic contact angles, contact lines, andlocal velocity fields for the case that a droplet displays on the micro structured surface.A spherical water droplet with r<sub>s</sub>= 15 μmfalls down to a biomimetic square-post patterned surface under the force of gravity with an initial velocity of 0.01 m·s<sup>-1</sup> and aninitial vertical distance of 20 μm from droplet centre to the top of pots.In spite of a higher initial velocity, the droplet can stillstay in a Cassie state; moreover, it reaches an equilibrium state at t≈17.5 ms, when contact angle is 153.16° which is slightlylower than the prediction of Cassie-Baxter’s equation which gives θ<sub>CB</sub>=154.40°.展开更多
It is well known that surface roughness has a very important effect on superhydrophobicity.The Wenzel and Cassie-Baxtermodels,which correspond to the homogeneous and heterogeneous wetting respectively,are currently pr...It is well known that surface roughness has a very important effect on superhydrophobicity.The Wenzel and Cassie-Baxtermodels,which correspond to the homogeneous and heterogeneous wetting respectively,are currently primary instructions fordesigning superhydrophobic surfaces.However,the particular drop shape that a drop exhibits might depend on how it is formed.A water drop can occupy multiple equilibrium states,which relate to different local minimal energy.In some cases,both equilibriumstates can even co-exist on a same substrate.Thus the apparent contact angles may vary and have different values.Wediscuss how the Wenzel and Cassie-Baxter equations determine the homogeneous and heterogeneous wetting theoretically.Contact angle analysis on hierarchical surface structure and contact angle hysteresis has been put specific attention.In particular,we study the energy barrier of transition from Cassie-Baxter state to Wenzel state,based on existing achievement by previousresearchers,to determine the possibility of the transition and how it can be interpreted.It has been demonstrated that surfaceroughness and geometry will influence the energy required for a drop to get into equilibrium,no matter it is homogeneous orheterogeneous wetting.展开更多
To meet the major challenge of increasing rice production to feed a growing population under increasing water scarcity,many water-saving regimes have been introduced in irrigated rice,such as an aerobic rice system,no...To meet the major challenge of increasing rice production to feed a growing population under increasing water scarcity,many water-saving regimes have been introduced in irrigated rice,such as an aerobic rice system,non-flooded mulching cultivation,and alternate wetting and drying(AWD).These regimes could substantially enhance water use efficiency(WUE) by reducing irrigation water.However,such enhancements greatly compromise grain yield.Recent work has shown that moderate AWD,in which photosynthesis is not severely inhibited and plants can rehydrate overnight during the soil drying period,or plants are rewatered at a soil water potential of-10 to-15 k Pa,or midday leaf potential is approximately-0.60 to-0.80 MPa,or the water table is maintained at 10 to 15 cm below the soil surface,could increase not only WUE but also grain yield.Increases in grain yield WUE under moderate AWD are due mainly to reduced redundant vegetative growth;improved canopy structure and root growth;elevated hormonal levels,in particular increases in abscisic acid levels during soil drying and cytokinin levels during rewatering;and enhanced carbon remobilization from vegetative tissues to grain.Moderate AWD could also improve rice quality,including reductions in grain arsenic accumulation,and reduce methane emissions from paddies.Adoption of moderate AWD with an appropriate nitrogen application rate may exert a synergistic effect on grain yield and result in higher WUE and nitrogen use efficiency.Further research is needed to understand root–soil interaction and evaluate the long-term effects of moderate AWD on sustainable agriculture.展开更多
In this study,FTIR and XPS spectroscopy,specific surface area and pore size analyses,wetting and other experimental means have been applied to investigate respirable coal dust surface properties and wetting mechanism....In this study,FTIR and XPS spectroscopy,specific surface area and pore size analyses,wetting and other experimental means have been applied to investigate respirable coal dust surface properties and wetting mechanism.The research shows that coal dust surface structures,chemical and element compositions are changed in the refining process of coal dust.Compared with large particle coal dust,respirable coal dust is a weak hydrophilic and strong hydrophobic substance.The reason:the smaller the particle size of coal dust,the more unsaturated its surface.The absorption of air is strong and it is easy to form an air film on coal dust surfaces. Coal dust contact with water is actually a compound contact of liquid in contact with a solid and gas in contact with a solid. The smaller the particle size,the larger the pore volume and the higher the degree of surface roughness,the larger the area of gas in contact with a solid and the worse the coal dust wettability.Another reason is that the changes in the composition of atoms on the dust surface and structures affect coal dust wettability.The results of this study establish a theoretical basis for the invention of effective reduced-dust technology.展开更多
Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-sav...Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-saving irrigation conditions.However,the mechanisms underlying these properties are unclear.We investigated how improved agronomic traits contribute to higher yield and higher water use efficiency(WUE)in DRRs than in DSRs under alternate wetting and drying(AWD).Two DRRs and two DSRs were field-grown in 2015 and 2016 using two different irrigation regimes:continuous flooding(CF)and AWD.Under CF,no statistical differences in grain yield and WUE were observed between DRRs and DSRs.Irrigation water under the AWD regime was 275–349 mm,an amount 49.8%–56.2% of that(552–620 mm)applied under the CF regime.Compared to CF,AWD significantly decreased grain yield in both DRRs and DSRs,with a more significant reduction in DSRs,and WUE was increased in DRRs,but not in DSRs,by 9.9%–23.0% under AWD.Under AWD,DRRs showed a 20.2%–26.2% increase in grain yield and an 18.6%–24.5% increase in WUE compared to DSRs.Compared to DSRs,DRRs showed less redundant vegetative growth,greater sink capacity,higher grain filling efficiency,larger root biomass,and deeper root distribution under AWD.We conclude that these improved agronomic traits exert positive influences on WUE in DRRs under AWD.展开更多
Wetting phenomena between MgO C and CaO SiO2 slags were investigated by varying carbon content.A sessile drop technique was adopted to study the wetting phenomena in conjunction with a high speed camera for the observ...Wetting phenomena between MgO C and CaO SiO2 slags were investigated by varying carbon content.A sessile drop technique was adopted to study the wetting phenomena in conjunction with a high speed camera for the observation of intrinsic wetting phenomena.The results show that the high content of SiO2 and the presence of Al2O3 in slags enhance the diffusion of Mg2+,leading to the promotion of reactive wetting.The carbon in MgO C refractory impedes the penetration of slags by repelling the slag and slowing the diffusion of Mg2+.This accounts for the non-wetting behavior of the slag on MgO C refractory with 17% (mass fraction) carbon similar to that of graphite.展开更多
The internal curing effect of superabsorbent polymer(SAP) on the properties of high performance concrete(HPC) under marine wetting and drying cycles(WD cycles) was investigated. Compressive strength, hydration and chl...The internal curing effect of superabsorbent polymer(SAP) on the properties of high performance concrete(HPC) under marine wetting and drying cycles(WD cycles) was investigated. Compressive strength, hydration and chloride migration were experimentally investigated and the results were evaluated by compasison with those under fresh water curing(FW). Water absorption and porosity were also evaluated only under WD cycles. The results showed the important influence of wetting and drying cycles on the properties of SAP modified HPC properties. Carefully designed, SAP minimized the long-term compressive strength of HPC under marine WD cycles. The hydration rate was faster in the initial curing, but became lower as compared with that cured in FW. In addition, SAP improved the long-term water absorption resistance and chloride migration resistance of HPC under marine WD cycles. The examination of the porosity showed a lower increase of the volume of capillary pores in SAP modified HPC under long term WD cycles compared with that without SAP. Therefore, internal curing by SAP could improve the durability properties of HPC under marine WD cycles.展开更多
基金This work was supported by the National Natural Science Foundation of China(32071943,32272198).
文摘Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG.
基金supported by the National key research and development program (2019YFA0607104)National Natural Science Foundation of China (Grant Nos. 41991231, 42275034, 41975076, 42075029, 42075017, and 42075018)the Gansu Provincial Science and Technology Project (22JR5RA405)。
文摘As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.
基金sponsored by the National Natural Science Foundation of China under Grant No.52206101Shanghai Sailing Program under Grant No.20YF1431200the Experiments for Space Exploration Program and the Qian Xuesen Laboratory,China Academy of Space Technology under Grant No.TKTSPY-2020-01-01.
文摘There are five most widely used contact angle schemes in the pseudopotential lattice Boltzmann(LB)model for simulating the wetting phenomenon:The pseudopotential-based scheme(PB scheme),the improved virtualdensity scheme(IVD scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the fluid layer density above the wall(MPB-C scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the weighted average density of surrounding fluid nodes(MPB-W scheme)and the geometric formulation scheme(GF scheme).But the numerical stability and accuracy of the schemes for wetting simulation remain unclear in the past.In this paper,the numerical stability and accuracy of these schemes are clarified for the first time,by applying the five widely used contact angle schemes to simulate a two-dimensional(2D)sessile droplet on wall and capillary imbibition in a 2D channel as the examples of static wetting and dynamic wetting simulations respectively.(i)It is shown that the simulated contact angles by the GF scheme are consistent at different density ratios for the same prescribed contact angle,but the simulated contact angles by the PB scheme,IVD scheme,MPB-C scheme and MPB-W scheme change with density ratios for the same fluid-solid interaction strength.The PB scheme is found to be the most unstable scheme for simulating static wetting at increased density ratios.(ii)Although the spurious velocity increases with the increased liquid/vapor density ratio for all the contact angle schemes,the magnitude of the spurious velocity in the PB scheme,IVD scheme and GF scheme are smaller than that in the MPB-C scheme and MPB-W scheme.(iii)The fluid density variation near the wall in the PB scheme is the most significant,and the variation can be diminished in the IVD scheme,MPB-C scheme andMPBWscheme.The variation totally disappeared in the GF scheme.(iv)For the simulation of capillary imbibition,the MPB-C scheme,MPB-Wscheme and GF scheme simulate the dynamics of the liquid-vapor interface well,with the GF scheme being the most accurate.The accuracy of the IVD scheme is low at a small contact angle(44 degrees)but gets high at a large contact angle(60 degrees).However,the PB scheme is the most inaccurate in simulating the dynamics of the liquid-vapor interface.As a whole,it is most suggested to apply the GF scheme to simulate static wetting or dynamic wetting,while it is the least suggested to use the PB scheme to simulate static wetting or dynamic wetting.
文摘The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and boundary conditions individually or collectively influence the hydraulic and volume change behavior of compacted highly expansive soils.The cyclic wetting and drying(CWD)process was applied for two boundary conditions,i.e.constant stress(CS)and constant volume(CV),and for a wide range of axial stress states.The adopted CWD process affected the hydraulic and volume change behaviors of expansive soils,with the first cycle of wetting and drying being the most effective.The CWD process under CS conditions resulted in shrinkage accumulation and reduction in saturated hydraulic conductivity(k sat).On the other hand,CWD under CV conditions caused a reduction of swell pressure while has almost no impact on k sat.An elastic response to CWD was achieved after the third cycle for saturated hydraulic conductivity(k sat),the third to fourth cycle for the volume change potential under the CV conditions,and the fourth to fifth cycle for the volume change potential under the CS conditions.Finally,both swell pressure(s s)and saturated hydraulic conductivity(k sat)are not fundamental parameters of the expansive soil but rather depend on stress,boundary and wetting conditions.
基金AGER-Fondazioni in rete per la ricerca agroalimentare(https://www.progettoager.it/)(Grant No.2010-2369)by Joint Programming Initiative on Agriculture,Food Security and Climate Change(FACCE-JPI)project Green Rice(Sustainable and environmental friendly rice cultivation systems in Europe).
文摘Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa.
基金This work was supported by National Natural Science Founda-tion of China(Grant Nos.41925012 and 41902271)Natural Science Foundation of Jiangsu Province(Grant No.BK20211087).
文摘Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of great significance for interpretation of soil macro hydro-mechanical behavior.In this review paper,methods that are commonly used to study soil microstructure are summarized.Among them are scanning electron microscope(SEM),environmental SEM(ESEM),mercury intrusion porosimetry(MIP)and computed tomography(CT)technology.Moreover,progress in research on the soil microstructure evolution during drying,wetting and wetting/drying cycles is summarized based on reviews of a large body of research papers published in the past several decades.Soils compacted on the wet side of op-timum water content generally have a matrix-type structure with a monomodal pore size distribution(PSD),whereas soils compacted on the dry side of optimum water content display an aggregate structure that exhibits bimodal PSD.During drying,decrease in soil volume is mainly caused by the shrinkage of inter-aggregate pores.During wetting,both the intra-and inter-aggregate pores increase gradually in number and sizes.Changes in the characteristics of the soil pore structure significantly depend on stress state as the soil is subjected to wetting.During wetting/drying cycles,soil structural change is not completely reversible,and the generated cumulative swelling/shrinkage deformation mainly derives from macro-pores.Furthermore,based on this analysis and identified research needs,some important areas of research focus are proposed for future work.These areas include innovative methods of sample preparation,new observation techniques,fast quantitative analysis of soil structure,integration of microstructural parameters into macro-mechanical models,and soil microstructure evolution charac-teristics under multi-field coupled conditions.
文摘MXenes are a class of 2D nanomaterials with exceptional tailormade properties such as mechano-ceramic nature,rich chemistry,and hydrophilicity,to name a few.However,one of the most challenging issues in any composite/hybrid system is the interfacial wetting.Having a superior integrity of a given composite system is a direct consequence of the proper wettability.While wetting is a fundamental feature,dictating many physical and chemical attributes,most of the common nanomaterials possesses poor affinity due to hydrophobic nature,making them hard to be easily dispersed in a given composite.Thanks to low contact angle,MXenes can offer themselves as an ideal candidate for manufacturing different nano-hybrid structures.Herein this review,it is aimed to particularly study the wettability of MXenes.In terms of the layout of the present study,MXenes are first briefly introduced,and then,the wettability phenomenon is discussed in detail.Upon reviewing the sporadic research efforts conducted to date,a particular attention is paid on the current challenges and research pitfalls to light up the future perspectives.It is strongly believed that taking the advantage of MXene’s rich hydrophilic surface may have a revolutionizing role in the fabrication of advanced materials with exceptional features.
基金supported by the National Natural Science Foundation of China(Nos.12272195,12272269 and 12262033)。
文摘Surface tension plays a central role in the mechanical behavior of soft materials such as gels.Elastocapillary deformation of elastic graded substrates is ubiquitous in soft materials.In this work,the effect of a partially wetting sessile liquid droplet on the elastocapillary deformation of a soft elastic graded substrate is studied.The modulus is assumed to have an exponential form along the thickness direction.By applying the Fourier transformation,a mixed boundary-value problem is reduced into a dual integral equation.The numerical results show that the surface displacement is strongly affected by the inhomogeneity of the material.The study of the wetting properties of gel substrates is essential for both understanding the wetting phenomena of gels and developing gels for applications as soft actuators and sensors that can be used in wearable electronics and soft robotics.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41905008, 41975007, and 42075081)the Innovation and Entrepreneurship Training Program for College Students of Chengdu University of Information Technology (CUIT) (202210621003, 202210621039, 202110621015)provided by the Scientific Research Foundation of CUIT (KYTZ202126)
文摘Since the 1990s,the Qinghai–Tibetan Plateau(QTP)has experienced a strikingly warming and wetter climate that alters the thermal and hydrological properties of frozen ground.A positive correlation between the warming and thermal degradation in permafrost or seasonally frozen ground(SFG)has long been recognized.Still,a predictive relationship between historical wetting under warming climate conditions and frozen ground has not yet been well demonstrated,despite the expectation that it will become even more important because precipitation over the QTP has been projected to increase continuously in the near future.This study investigates the response of the thermal regime to historical wetting in both permafrost and SFG areas and examines their relationships separately using the Community Land Surface Model version 4.5.Results show that wetting before the 1990s across the QTP mainly cooled the permafrost body in the arid and semiarid zones,with significant correlation coefficients of 0.60 and 0.48,respectively.Precipitation increased continually at the rate of 6.16 mm decade–1 in the arid zone after the 1990s but had a contrasting warming effect on permafrost through a significant shortening of the thawing duration within the active layer.However,diminished rainfall in the humid zone after the 1990s also significantly extended the thawing duration of SFG.The relationship between the ground thawing index and precipitation was significantly negatively correlated(−0.75).The dual effects of wetting on the thermal dynamics of the QTP are becoming critical because of the projected increases in future precipitation.
基金the National Natural Science Foundation of China(Grant No.51976002)the Beijing Nova Program of Science and Technology(Grant No.Z191100001119033)。
文摘Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectification phenomenon in an asymmetric solid–liquid–solid sandwiched system with a nano-structured interface.By using the non-equilibrium molecular dynamics simulations,the thermal transport through the solid–liquid–solid system is examined,and the thermal rectification phenomenon can be observed.It is revealed that the thermal rectification effect can be attributed to the significant difference in the interfacial thermal resistance between Cassie and Wenzel states when reversing the temperature bias.In addition,effects of the liquid density,solid–liquid bonding strength and nanostructure size on the thermal rectification are examined.The findings may provide a new way for designs of certain thermal devices.
基金supported by the Major Program of National Natural Science Foundation of China(No.41790441)the National Natural Science Foundation of China(No.41807234,41907235)the Fundamental Research Funds for the Central Universities,CHD(300102269203)。
文摘Loess is prone to collapse upon wetting due to its open metastable structure,which poses a considerable threat to the environment,construction processes and human life.In this study,double oedometer tests and scanning electron microscopy and mercury intrusion porosimetry analyses were conducted on loess from Yan’an to study the macroscopic and microscopic characteristics of loess wetting deformation and the underlying mechanism.The wetting collapse of loess under loading depends on the changes in different microstructure levels and elements.This collapse chain reaction is manifested by the dissipation,scattering and recombination of the cementation,deformation and reorganization of the particles,blocking of the pore channels,decrease in the dominant size and volume of unstable macropores(>14μm)and abundant mesopores(2.5-14μm),increase in the volume of small pores(0.05–2.5μm),and volume contraction at the macroscale.This process is dependent on the initial water content,stress level and wetting degree.These findings can facilitate collapsible loess hazard prevention and geological engineering construction.
基金sponsored by the National Natural Science Foundation of China(31461143015,31271641,31471438)the National Key Technology Support Program of China(2014AA10A605,216YFD0300206-4)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),Chinathe Jiangsu Creation Program for Post-graduation Students,China(KYZZ15_0364)
文摘This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency(WUE) under alternate wetting and drying(AWD) irrigation than check rice. Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered(WW), moderate water deficit(MWD) and severe water deficit(SWD). Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying(AWMD), alternate wetting and severe drying(AWSD) and conventional irrigation(CI). Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice. Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD. Compared with CI, AWMD increased, whereas AWSD decreased grain yield, with more increase or less decrease for super rice than for check rice. Both MWD and SWD treatments and either AWMD or AWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice. The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.
文摘Wetting and spreading processes which involve surfactant solutions are widely used in numerous industrial and practicalapplications nowadays.The performance of different non-ionic surfactants may vary significantly and so far superspreadersolutions show the most promising spreading ability.The addition of trisiloxane surfactants to water was proven to enhancewetting,even on hydrophobic surfaces,on which conventional surfactants seem to have little or no effect.Although theseextraordinary surfactants have been extensively studied over recent years,complete understanding of their underlying mechanismsand a suitable mathematical model are still lacking.Here we present a possible explanation for the impressive performanceof trisiloxane,which is compared to wetting enhancement of a conventional surfactant.Additionally,we will explain whythe hydrophobicity of the surface is a crucial factor for the spreading phenomenon.Light will be also shed on the effect of the pHof the solution to which surfactants are added.Finally,we will investigate long-term effects of the water environment on trisiloxanewetting ability and discuss if ageing may significantly affect their performance.
基金supported by the Royal Society(UK)-NSFC(China)joint project,2009-2011by China Natural Science Foundation major International collaborative project 2010-2013 under grant No.50920105504
文摘Natural surfaces with super hydrophobic properties often have micro or hierarchical structures.In this paper, the wettingbehaviours of a single droplet on biomimetic micro structured surfaces with different roughness parameters are investigated.Atheoretical model is proposed to study wetting transitions.The results of theoretical analysis are compared with those of experimentindicating that the proposed model can effectively predict the wetting transition.Furthermore, a numerical simulationbased on the meso scale Lattice Boltzmann Method （LBM） is performed to study dynamic contact angles, contact lines, andlocal velocity fields for the case that a droplet displays on the micro structured surface.A spherical water droplet with r<sub>s</sub>= 15 μmfalls down to a biomimetic square-post patterned surface under the force of gravity with an initial velocity of 0.01 m·s<sup>-1</sup> and aninitial vertical distance of 20 μm from droplet centre to the top of pots.In spite of a higher initial velocity, the droplet can stillstay in a Cassie state; moreover, it reaches an equilibrium state at t≈17.5 ms, when contact angle is 153.16° which is slightlylower than the prediction of Cassie-Baxter’s equation which gives θ<sub>CB</sub>=154.40°.
文摘It is well known that surface roughness has a very important effect on superhydrophobicity.The Wenzel and Cassie-Baxtermodels,which correspond to the homogeneous and heterogeneous wetting respectively,are currently primary instructions fordesigning superhydrophobic surfaces.However,the particular drop shape that a drop exhibits might depend on how it is formed.A water drop can occupy multiple equilibrium states,which relate to different local minimal energy.In some cases,both equilibriumstates can even co-exist on a same substrate.Thus the apparent contact angles may vary and have different values.Wediscuss how the Wenzel and Cassie-Baxter equations determine the homogeneous and heterogeneous wetting theoretically.Contact angle analysis on hierarchical surface structure and contact angle hysteresis has been put specific attention.In particular,we study the energy barrier of transition from Cassie-Baxter state to Wenzel state,based on existing achievement by previousresearchers,to determine the possibility of the transition and how it can be interpreted.It has been demonstrated that surfaceroughness and geometry will influence the energy required for a drop to get into equilibrium,no matter it is homogeneous orheterogeneous wetting.
基金the National Basic Research Program(973 Program,No.2012CB114306)the National Natural Science Foundation of China(Nos.31461143015+5 种基金31271641,31471438)the National Key Technology Support Program of China(Nos.2014AA10A6052012BAD04B08)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Top Talent Supporting Program of Yangzhou University(No.2015-01)Jiangsu Creation Program for Postgraduate Students(No.KYZZ15_0364)
文摘To meet the major challenge of increasing rice production to feed a growing population under increasing water scarcity,many water-saving regimes have been introduced in irrigated rice,such as an aerobic rice system,non-flooded mulching cultivation,and alternate wetting and drying(AWD).These regimes could substantially enhance water use efficiency(WUE) by reducing irrigation water.However,such enhancements greatly compromise grain yield.Recent work has shown that moderate AWD,in which photosynthesis is not severely inhibited and plants can rehydrate overnight during the soil drying period,or plants are rewatered at a soil water potential of-10 to-15 k Pa,or midday leaf potential is approximately-0.60 to-0.80 MPa,or the water table is maintained at 10 to 15 cm below the soil surface,could increase not only WUE but also grain yield.Increases in grain yield WUE under moderate AWD are due mainly to reduced redundant vegetative growth;improved canopy structure and root growth;elevated hormonal levels,in particular increases in abscisic acid levels during soil drying and cytokinin levels during rewatering;and enhanced carbon remobilization from vegetative tissues to grain.Moderate AWD could also improve rice quality,including reductions in grain arsenic accumulation,and reduce methane emissions from paddies.Adoption of moderate AWD with an appropriate nitrogen application rate may exert a synergistic effect on grain yield and result in higher WUE and nitrogen use efficiency.Further research is needed to understand root–soil interaction and evaluate the long-term effects of moderate AWD on sustainable agriculture.
基金Financial support for this work,provided by the Science and Technology Project of the Education Department of Shandong Province(No.J08LC12),
文摘In this study,FTIR and XPS spectroscopy,specific surface area and pore size analyses,wetting and other experimental means have been applied to investigate respirable coal dust surface properties and wetting mechanism.The research shows that coal dust surface structures,chemical and element compositions are changed in the refining process of coal dust.Compared with large particle coal dust,respirable coal dust is a weak hydrophilic and strong hydrophobic substance.The reason:the smaller the particle size of coal dust,the more unsaturated its surface.The absorption of air is strong and it is easy to form an air film on coal dust surfaces. Coal dust contact with water is actually a compound contact of liquid in contact with a solid and gas in contact with a solid. The smaller the particle size,the larger the pore volume and the higher the degree of surface roughness,the larger the area of gas in contact with a solid and the worse the coal dust wettability.Another reason is that the changes in the composition of atoms on the dust surface and structures affect coal dust wettability.The results of this study establish a theoretical basis for the invention of effective reduced-dust technology.
基金the National Key Research and Development Program of China (2016YFD0300507,2016YFD0300108)the National Natural Science Foundation of China (31671630,31671638,31501264)the China Agriculture Research System (CARS-01)
文摘Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-saving irrigation conditions.However,the mechanisms underlying these properties are unclear.We investigated how improved agronomic traits contribute to higher yield and higher water use efficiency(WUE)in DRRs than in DSRs under alternate wetting and drying(AWD).Two DRRs and two DSRs were field-grown in 2015 and 2016 using two different irrigation regimes:continuous flooding(CF)and AWD.Under CF,no statistical differences in grain yield and WUE were observed between DRRs and DSRs.Irrigation water under the AWD regime was 275–349 mm,an amount 49.8%–56.2% of that(552–620 mm)applied under the CF regime.Compared to CF,AWD significantly decreased grain yield in both DRRs and DSRs,with a more significant reduction in DSRs,and WUE was increased in DRRs,but not in DSRs,by 9.9%–23.0% under AWD.Under AWD,DRRs showed a 20.2%–26.2% increase in grain yield and an 18.6%–24.5% increase in WUE compared to DSRs.Compared to DSRs,DRRs showed less redundant vegetative growth,greater sink capacity,higher grain filling efficiency,larger root biomass,and deeper root distribution under AWD.We conclude that these improved agronomic traits exert positive influences on WUE in DRRs under AWD.
基金supported by the R&D Center for Valuable Recycling(Global-Top Environmental Technology Development Program)funded by the Ministry of Environment(Project No.:11-C22-ID)
文摘Wetting phenomena between MgO C and CaO SiO2 slags were investigated by varying carbon content.A sessile drop technique was adopted to study the wetting phenomena in conjunction with a high speed camera for the observation of intrinsic wetting phenomena.The results show that the high content of SiO2 and the presence of Al2O3 in slags enhance the diffusion of Mg2+,leading to the promotion of reactive wetting.The carbon in MgO C refractory impedes the penetration of slags by repelling the slag and slowing the diffusion of Mg2+.This accounts for the non-wetting behavior of the slag on MgO C refractory with 17% (mass fraction) carbon similar to that of graphite.
基金Funded by National Key Research and Development Program of China(No.2017YFB0310000)Opening Project of State Key Laboratory of Green Building Materials(No.YA-584)the Key Technology Innovation Program from the Ministry of Science and Technology(Hubei Province)(No.2018AAA004)
文摘The internal curing effect of superabsorbent polymer(SAP) on the properties of high performance concrete(HPC) under marine wetting and drying cycles(WD cycles) was investigated. Compressive strength, hydration and chloride migration were experimentally investigated and the results were evaluated by compasison with those under fresh water curing(FW). Water absorption and porosity were also evaluated only under WD cycles. The results showed the important influence of wetting and drying cycles on the properties of SAP modified HPC properties. Carefully designed, SAP minimized the long-term compressive strength of HPC under marine WD cycles. The hydration rate was faster in the initial curing, but became lower as compared with that cured in FW. In addition, SAP improved the long-term water absorption resistance and chloride migration resistance of HPC under marine WD cycles. The examination of the porosity showed a lower increase of the volume of capillary pores in SAP modified HPC under long term WD cycles compared with that without SAP. Therefore, internal curing by SAP could improve the durability properties of HPC under marine WD cycles.
