A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm is based on differential geometry theory on necessary and sufficient condition...A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm is based on differential geometry theory on necessary and sufficient conditions for a surface which is developable, and on degree evaluation formula for parameter curves and linear independence for Bernstein basis. No nonlinear characteristic equations have to be solved. Moreover the vertex for a cone and the edge of regression for a tangent surface can be obtained easily. Aumann’s algorithm for developable surfaces is a special case of this paper.展开更多
The paper deals with the principle of envelope of a one-parameter plane family to design developable surfaces. Three methods of designing developable surfaces are presented. They are designing a developable surface ba...The paper deals with the principle of envelope of a one-parameter plane family to design developable surfaces. Three methods of designing developable surfaces are presented. They are designing a developable surface based on one curve on it and its normal line, designing a developable surface based on two curves on it and designing a developable surface based on one curve and one surface. They meet the requirements of engineering fields.展开更多
Curvature lines are special and important curves on surfaces.It is of great significance to construct developable surface interpolated on curvature lines in engineering applications.In this paper,the shape optimizatio...Curvature lines are special and important curves on surfaces.It is of great significance to construct developable surface interpolated on curvature lines in engineering applications.In this paper,the shape optimization of generalized cubic ball developable surface interpolated on the curvature line is studied by using the improved reptile search algorithm.Firstly,based on the curvature line of generalized cubic ball curve with shape adjustable,this paper gives the construction method of SGC-Ball developable surface interpolated on the curve.Secondly,the feedback mechanism,adaptive parameters and mutation strategy are introduced into the reptile search algorithm,and the Feedback mechanism-driven improved reptile search algorithm effectively improves the solving precision.On IEEE congress on evolutionary computation 2014,2017,2019 and four engineering design problems,the feedback mechanism-driven improved reptile search algorithm is compared with other representative methods,and the result indicates that the solution performance of the feedback mechanism-driven improved reptile search algorithm is competitive.At last,taking the minimum energy as the evaluation index,the shape optimization model of SGC-Ball interpolation developable surface is established.The developable surface with the minimum energy is achieved with the help of the feedback mechanism-driven improved reptile search algorithm,and the comparison experiment verifies the superiority of the feedback mechanism-driven improved reptile search algorithm for the shape optimization problem.展开更多
Background Early embryo development plays a pivotal role in determining pregnancy outcomes,postnatal development,and lifelong health.Therefore,the strategic selection of functional nutrients to enhance embryo developm...Background Early embryo development plays a pivotal role in determining pregnancy outcomes,postnatal development,and lifelong health.Therefore,the strategic selection of functional nutrients to enhance embryo development is of paramount importance.In this study,we established a stable porcine trophectoderm cell line expressing dual fluorescent reporter genes driven by the CDX2 and TEAD4 gene promoter segments using lentiviral transfection.Results Three amino acid metabolites—kynurenic acid,taurine,and tryptamine—met the minimum z-score criteria of 2.0 for both luciferase and Renilla luciferase activities and were initially identified as potential metabolites for embryo development,with their beneficial effects validated by qPCR.Given that the identified metabolites are closely related to methionine,arginine,and tryptophan,we selected these three amino acids,using lysine as a standard,and employed response surface methodology combined with our high-throughput screening cell model to efficiently screen and optimize amino acid combination conducive to early embryo development.The optimized candidate amino acid system included lysine(1.87 mmol/L),methionine(0.82 mmol/L),tryptophan(0.23 mmol/L),and arginine(3 mmol/L),with the ratio of 1:0.43:0.12:1.60.In vitro experiments confirmed that this amino acid system enhances the expression of key genes involved in early embryonic development and improves in vitro embryo adhesion.Transcriptomic analysis of blastocysts suggested that candidate amino acid system enhances early embryo development by regulating early embryonic cell cycle and differentiation,as well as improving nutrient absorption.Furthermore,based on response surface methodology,400 sows were used to verify this amino acid system,substituting arginine with the more cost-effective N-carbamoyl glutamate(NCG),a precursor of arginine.The optimal dietary amino acid requirement was predicted to be 0.71%lysine,0.32%methionine,0.22%tryptophan,and 0.10%NCG for sows during early gestation.The optimized amino acid system ratio of the feed,derived from the peripheral release of essential amino acids,was found to be 1:0.45:0.13,which is largely consistent with the results obtained from the cell model optimization.Subsequently,we furtherly verified that this optimal dietary amino acid system significantly increased total litter size,live litter size and litter weight in sows.Conclusions In summary,we successfully established a dual-fluorescent high-throughput screening cell model for the efficient identification of potential nutrients that would promote embryo development and implantation.This innovative approach overcomes the limitations of traditional amino acid nutrition studies in sows,providing a more effective model for enhancing reproductive outcomes.展开更多
The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability.In this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy...The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability.In this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy,and examined the effect of sea surface temperature(SST)in its critical early life stages on subsequent yields.To analyze the correlation between SST in different larval stages and the corresponding yield of P.trituberculatus,we simulated the transport and distribution of larvae from 2014 to 2022 by employing circulation models and Lagrangian particle tracking experiments(LPTE).In the five years(2014,2015,2016,2019,and 2020),particles were transported in a northwestern direction and moved in the direction of low SST.The distribution of particles in the megalopa stage(M stage)were located in the region of the lower temperature.In 2017,2018,and 2021,the particles were transported in a northeastern direction but they did not move with the gradient of low SST in these years,and the particles in the last M stage were located in the region where the SST was at the peak of the time period.In 2022,the distribution was observed for most of the particles in the southwestern part of Zhejiang coast,a small part of them were transported in the northwestern direction and a small amount of particles was distributed offshore along the northern area of the Zhejiang coast.The correlations between the SST at each stage of larvae with the corresponding year's yield showed that the yield of P.trituberculatus decreased significantly(R=-0.772,P=0.015)with increasing SST at the M stage.This study preliminarily explains the correlation between SST at the larval stage and the yield of P.trituberculatus and provides essential information for scientific stock enhancement in the future.展开更多
In this study, the Crop Estimation through Resource and Environment Synthesis model （CERES3.0） was coupled into the Biosphere-Atmosphere Transfer Scheme （BATS）, which is called BATS CERES, to represent interaction...In this study, the Crop Estimation through Resource and Environment Synthesis model （CERES3.0） was coupled into the Biosphere-Atmosphere Transfer Scheme （BATS）, which is called BATS CERES, to represent interactions between the land surface and crop growth processes. The effects of crop growth and development on land surface processes were then studied based on numerical simulations using the land surface models. Six sensitivity experiments by BATS show that the land surface fluxes underwent substantial changes when the leaf area index was changed from 0 to 6 m2 m-2. Numerical experiments for Yucheng and Taoyuan stations reveal that the coupled model could capture not only the responses of crop growth and development to environmental conditions, but also the feedbacks to land surface processes. For quantitative evaluation of the effects of crop growth and development on surface fluxes in China, two numerical experiments were conducted over continental China： one by BATS CERES and one by the original BATS. Comparison of the two runs shows decreases of leaf area index and fractional vegetation cover when incorporating dynamic crops in land surface simulation, which lead to less canopy interception, vegetation transpiration, total evapotranspiration, top soil moisture, and more soil evaporation, surface runoff, and root zone soil moisture. These changes are accompanied by decreasing latent heat flux and increasing sensible heat flux in the cropland region. In addition, the comparison between the simulations and observations proved that incorporating the crop growth and development process into the land surface model could reduce the systematic biases of the simulated leaf area index and top soil moisture, hence improve the simulation of land surface fluxes.展开更多
1.Introduction Surface integrity has great significance for the quality and performance of machined components,and has therefore been increasingly recognized by industry.In particular,within certain industries that re...1.Introduction Surface integrity has great significance for the quality and performance of machined components,and has therefore been increasingly recognized by industry.In particular,within certain industries that require high reliability,such as the aerospace industry,surface integrity is one of the most relevant indexes used to evaluate the quality of machined parts.Thus,obtaining updated knowledge on surface integrity is of great interest to both the academic community and industry[1].展开更多
Quantum dots(QDs)are new types of nanomaterials.Few studies have focused on the effect of different surface modified QDs on embryonic development.Herein,we compared the in vivo toxicity of Cd Se/Zn S QDs with carboxyl...Quantum dots(QDs)are new types of nanomaterials.Few studies have focused on the effect of different surface modified QDs on embryonic development.Herein,we compared the in vivo toxicity of Cd Se/Zn S QDs with carboxyl(-COOH)and amino(-NH 2)modification using zebrafish embryos.After exposure,the two Cd Se/Zn S QDs decreased the survival rate,hatching rate,and embryo movement of zebrafish.Moreover,we found QDs attached to the embryo membrane before hatching and the eyes,yolk and heart after hatching.The attached amount of carboxyl QDs was more.Consistently,the Cd content in embryos and larvae was higher in carboxyl QD-treatment.We further observed that the two QDs caused zebrafish pericardial edema and cardiac dysfunction.In line with it,both carboxyl and amino QDs upregulated the transcription levels of cardiac development-related genes,and the levels were higher in carboxyl QD-treated groups.Furthermore,the chelator of Cd^2+diethylene triamine pentacetate acid could partially rescued the developmental toxicity caused by the two types of QDs suggesting that both the nature of QDs and the release of Cd^2+contribute to the developmental toxicity.In conclusion,the two Cd Se/ZnS QDs have developmental toxicity and affect the cardiac development,and the carboxyl QDs is more toxic possibly due to the higher affinity and more release to embryos and larvae.Our study provides new knowledge that the surface functional modification of QDs is critical on the development on aquatic species,which is beneficial to develop and applicate QDs more safely and environmentfriendly.展开更多
Surface morphology of soil cracks is one of the important factors influencing the water evaporation rate in cracked soil in Yuanmou Dry-hot Valley Region,Southwest China. Quantitative study of the complicated surface ...Surface morphology of soil cracks is one of the important factors influencing the water evaporation rate in cracked soil in Yuanmou Dry-hot Valley Region,Southwest China. Quantitative study of the complicated surface morphology of soil cracks is a prerequisite for further studies of soil-cracking mechanisms. The present paper establishes a quantitative indicator system by application of concepts and methods originating from Fractal Geometry and Network Analysis. These indicators can effectively express the complicated features of soil-crack network structure. Furthermore,a series of values related to soil-crack morphology was obtained by image processing on field photos of soil-crack quads,and gradation criteria for the degree of development of soil cracks were determined. Finally,the changes in values of the morphological indicators under different degrees of development were analyzed in detail. Our results indicate that (1) the degree of development of soil cracks can be divided into five grades,i.e.,feeble development,slight development,medium development,intensive development and extremely intensive development; (2) the values of the indicators change predictably with increasing degree of development of soil cracks. The area density (Dc) increases,and both the area-weighted mean ratio of crack area to perimeter (AWMARP),which reflects the intensity of cracking,and the index r,which is related to the connectivity of a soil crack,grow uniformly (albeit with different forms). AWMRAP increases at a geometric rate while r shows logarithm-mic growth,indicating a gradual increase in theconnectivity of a soil crack. Nevertheless,the area-weighted mean of soil-crack fractal dimension (AWMFRAC) shows a decreasing trend,indicating a gradual decline in the complexity of cracks as area density increases.展开更多
Understanding the sensitivity of tidal flats to environmental changes is challenging.Currently,most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal flats.In this stu...Understanding the sensitivity of tidal flats to environmental changes is challenging.Currently,most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal flats.In this study,we proposed an alternative empirical approach to explore tidal flat dynamics using statistical indices based on long-term time series of daily surface elevation development.Surface elevation dynamic(SED)indices focus on the magnitude and period of surface elevation changes,while morphodynamic signature(MDS)indices relate sediment dynamics to environmental drivers.The statistical analyses were applied to an intervention site in the Netherlands to determine the effect of recently constructed groynes on the tidal flat.Using these analyses,we were able to(1)detect a reduction in the daily SED and(2)determine that the changes in the daily SED were predominantly caused by the reduction in wave impact between the groynes rather than the reduction in tidal currents.Overall,the presented results showed that the combination of novel statistical indices provides new insights into the trajectories of tidal flats,ecosystem functioning,and sensitivity to physical drivers(wind and tides).Finally,we suggested how the SED and MDS indices may help to explore the future trajectories and climate resilience of intertidal habitats.展开更多
According to the characteristics of a complex cover panel, its geometry shape is described by the NURBS surface with great description capability. With the reference to the surface classification determined by Gauss c...According to the characteristics of a complex cover panel, its geometry shape is described by the NURBS surface with great description capability. With the reference to the surface classification determined by Gauss curvature, the proportion of the mid-surface area between before and after being developed is derived from the displacement variation of the mid-surface in the normal vector direction of the sheet metal during the sheet metal forming process. Hereby, based on the curve development theory in differential geometry, a novel diagonal point by point surface development method is put forward to estimate a complex cover panel＇s blank contour efficiently. By comparing the sample＇s development result of diagonal point by point surface development method with that of available one-step method, the validity of the proposed surface development method is verified.展开更多
Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperatu...Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019.展开更多
Environmental pollution is a by product of industrialization when economy of a region is developing. China also suffers from such a problem, especially in the southern part like Suzhou region in Jiangsu Province. In t...Environmental pollution is a by product of industrialization when economy of a region is developing. China also suffers from such a problem, especially in the southern part like Suzhou region in Jiangsu Province. In this paper, data covering situations of surface water pollution and social and economic development showed that the surface water pollution in Taicang County, a typical economic zone of Suzhou region, is significantly correlated to the economic growth of this region.展开更多
Development of curved surface is a useful tool in CAD(computer aided design) and CAGD(computer aided geometric design).This paper presents the algorithms for developing (flattening) a smooth continuous curved surface ...Development of curved surface is a useful tool in CAD(computer aided design) and CAGD(computer aided geometric design).This paper presents the algorithms for developing (flattening) a smooth continuous curved surface embedded in three dimensional space into a planar shape. First the definition of planar development of a curved surface is presented, and the distortions (at length and area) of development are discussed in this paper. Then several planar flattening methods of curved surface, and their advantages and disadvantages are analyzed in detail. For NURBS(non uniform rational basic spline) surfaces, which are broadly used in CAGD, we put forward a new planar developing algorithm, i.e. hybrid developing, and present the steps of the algorithm. At last, some examples are used to show the effectiveness of the algorithm.展开更多
The rapid growth and early development period of the dual-scale surface topography was studied on the adaxial leaf surfaces of two aspen tree species with non-wetting leaves: the columnar European aspen (Populus tremu...The rapid growth and early development period of the dual-scale surface topography was studied on the adaxial leaf surfaces of two aspen tree species with non-wetting leaves: the columnar European aspen (Populus tremula “Erecta”) and quaking aspen (Populus tremuloides). Particular attention was focused on the formation of micro- and nano-scale asperities on their cuticles, which was correlated with the development of superhydrophobic wetting behaviour. Measurements of the wetting properties (contact angle and tilt-angle) provided an indication of the degree of hydrophobicity of their cuticles. Scanning electron microscopy and optical profilometry micrographs were used to follow the growth and major morphological changes of micro-scale papillae and nano-scale epicuticular wax (ECW) crystals, which led to a significant improvement in non-wetting behaviour. Both species exhibited syntopism in the form of small and larger nano-scale ECW platelet morphologies. These findings provide additional support for earlier suggestions that due to fluctuations in leaf hydrophobicity throughout the growing season, canopy storage capacity may also vary considerably throughout this time period.展开更多
To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are us...To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are used to prepare biomimetic structured surfaces with different wettability.The impingement processes of diesel and n-butanol sprays on the walls under different conditions are experimentally investigated.As the surface oleophilicity increases,the spreading radius of wall-impinging sprays decreases.At about 5 s after the fuel injections,the fuel spray droplets hit the walls for the first time,and the secondary breakup and rebound occur.The mixture concentrations of different fuels hitting the various walls reach the peak value.Under a higher surface temperature,the peak value of the mixture concentration is mainly related to the heat flux to the fuel droplets in different boiling regimes from the metal surfaces.The concentration of the air–fuel mixture in the near wall region increases with increasing surface oleophilicity,increasing wall temperature and decreasing ambient pressure.Compared with diesel,n-butanol presents a higher air–fuel mixture concentration in the near wall region.展开更多
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB719400), the National Natural Science Founda-tion of China (Nos. 60373033 and 60333010) and the National Natural Science Foundation for Innovative Research Groups (No. 60021201), China
文摘A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm is based on differential geometry theory on necessary and sufficient conditions for a surface which is developable, and on degree evaluation formula for parameter curves and linear independence for Bernstein basis. No nonlinear characteristic equations have to be solved. Moreover the vertex for a cone and the edge of regression for a tangent surface can be obtained easily. Aumann’s algorithm for developable surfaces is a special case of this paper.
文摘The paper deals with the principle of envelope of a one-parameter plane family to design developable surfaces. Three methods of designing developable surfaces are presented. They are designing a developable surface based on one curve on it and its normal line, designing a developable surface based on two curves on it and designing a developable surface based on one curve and one surface. They meet the requirements of engineering fields.
基金supported by the National Natural Science Foundation of China(Grant No.52375264).
文摘Curvature lines are special and important curves on surfaces.It is of great significance to construct developable surface interpolated on curvature lines in engineering applications.In this paper,the shape optimization of generalized cubic ball developable surface interpolated on the curvature line is studied by using the improved reptile search algorithm.Firstly,based on the curvature line of generalized cubic ball curve with shape adjustable,this paper gives the construction method of SGC-Ball developable surface interpolated on the curve.Secondly,the feedback mechanism,adaptive parameters and mutation strategy are introduced into the reptile search algorithm,and the Feedback mechanism-driven improved reptile search algorithm effectively improves the solving precision.On IEEE congress on evolutionary computation 2014,2017,2019 and four engineering design problems,the feedback mechanism-driven improved reptile search algorithm is compared with other representative methods,and the result indicates that the solution performance of the feedback mechanism-driven improved reptile search algorithm is competitive.At last,taking the minimum energy as the evaluation index,the shape optimization model of SGC-Ball interpolation developable surface is established.The developable surface with the minimum energy is achieved with the help of the feedback mechanism-driven improved reptile search algorithm,and the comparison experiment verifies the superiority of the feedback mechanism-driven improved reptile search algorithm for the shape optimization problem.
基金supported by National Natural Science Foundation of China (32172747 and 32425052)
文摘Background Early embryo development plays a pivotal role in determining pregnancy outcomes,postnatal development,and lifelong health.Therefore,the strategic selection of functional nutrients to enhance embryo development is of paramount importance.In this study,we established a stable porcine trophectoderm cell line expressing dual fluorescent reporter genes driven by the CDX2 and TEAD4 gene promoter segments using lentiviral transfection.Results Three amino acid metabolites—kynurenic acid,taurine,and tryptamine—met the minimum z-score criteria of 2.0 for both luciferase and Renilla luciferase activities and were initially identified as potential metabolites for embryo development,with their beneficial effects validated by qPCR.Given that the identified metabolites are closely related to methionine,arginine,and tryptophan,we selected these three amino acids,using lysine as a standard,and employed response surface methodology combined with our high-throughput screening cell model to efficiently screen and optimize amino acid combination conducive to early embryo development.The optimized candidate amino acid system included lysine(1.87 mmol/L),methionine(0.82 mmol/L),tryptophan(0.23 mmol/L),and arginine(3 mmol/L),with the ratio of 1:0.43:0.12:1.60.In vitro experiments confirmed that this amino acid system enhances the expression of key genes involved in early embryonic development and improves in vitro embryo adhesion.Transcriptomic analysis of blastocysts suggested that candidate amino acid system enhances early embryo development by regulating early embryonic cell cycle and differentiation,as well as improving nutrient absorption.Furthermore,based on response surface methodology,400 sows were used to verify this amino acid system,substituting arginine with the more cost-effective N-carbamoyl glutamate(NCG),a precursor of arginine.The optimal dietary amino acid requirement was predicted to be 0.71%lysine,0.32%methionine,0.22%tryptophan,and 0.10%NCG for sows during early gestation.The optimized amino acid system ratio of the feed,derived from the peripheral release of essential amino acids,was found to be 1:0.45:0.13,which is largely consistent with the results obtained from the cell model optimization.Subsequently,we furtherly verified that this optimal dietary amino acid system significantly increased total litter size,live litter size and litter weight in sows.Conclusions In summary,we successfully established a dual-fluorescent high-throughput screening cell model for the efficient identification of potential nutrients that would promote embryo development and implantation.This innovative approach overcomes the limitations of traditional amino acid nutrition studies in sows,providing a more effective model for enhancing reproductive outcomes.
基金Supported by the National Key Research and Development Program of China(No.2019YFD0901304)the Public Welfare Technology Application Research Project of Zhejiang(No.LGN21C190009)the Science and Technology Project of Zhoushan(No.2022C41003)。
文摘The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability.In this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy,and examined the effect of sea surface temperature(SST)in its critical early life stages on subsequent yields.To analyze the correlation between SST in different larval stages and the corresponding yield of P.trituberculatus,we simulated the transport and distribution of larvae from 2014 to 2022 by employing circulation models and Lagrangian particle tracking experiments(LPTE).In the five years(2014,2015,2016,2019,and 2020),particles were transported in a northwestern direction and moved in the direction of low SST.The distribution of particles in the megalopa stage(M stage)were located in the region of the lower temperature.In 2017,2018,and 2021,the particles were transported in a northeastern direction but they did not move with the gradient of low SST in these years,and the particles in the last M stage were located in the region where the SST was at the peak of the time period.In 2022,the distribution was observed for most of the particles in the southwestern part of Zhejiang coast,a small part of them were transported in the northwestern direction and a small amount of particles was distributed offshore along the northern area of the Zhejiang coast.The correlations between the SST at each stage of larvae with the corresponding year's yield showed that the yield of P.trituberculatus decreased significantly(R=-0.772,P=0.015)with increasing SST at the M stage.This study preliminarily explains the correlation between SST at the larval stage and the yield of P.trituberculatus and provides essential information for scientific stock enhancement in the future.
基金supported by the National Basic Research Program under Grant Nos.2010CB428403, 2010CB951001, and 2009CB421407the National Natural Science Foundation of China under Grant Nos. 41075062 and 40821092
文摘In this study, the Crop Estimation through Resource and Environment Synthesis model （CERES3.0） was coupled into the Biosphere-Atmosphere Transfer Scheme （BATS）, which is called BATS CERES, to represent interactions between the land surface and crop growth processes. The effects of crop growth and development on land surface processes were then studied based on numerical simulations using the land surface models. Six sensitivity experiments by BATS show that the land surface fluxes underwent substantial changes when the leaf area index was changed from 0 to 6 m2 m-2. Numerical experiments for Yucheng and Taoyuan stations reveal that the coupled model could capture not only the responses of crop growth and development to environmental conditions, but also the feedbacks to land surface processes. For quantitative evaluation of the effects of crop growth and development on surface fluxes in China, two numerical experiments were conducted over continental China： one by BATS CERES and one by the original BATS. Comparison of the two runs shows decreases of leaf area index and fractional vegetation cover when incorporating dynamic crops in land surface simulation, which lead to less canopy interception, vegetation transpiration, total evapotranspiration, top soil moisture, and more soil evaporation, surface runoff, and root zone soil moisture. These changes are accompanied by decreasing latent heat flux and increasing sensible heat flux in the cropland region. In addition, the comparison between the simulations and observations proved that incorporating the crop growth and development process into the land surface model could reduce the systematic biases of the simulated leaf area index and top soil moisture, hence improve the simulation of land surface fluxes.
文摘1.Introduction Surface integrity has great significance for the quality and performance of machined components,and has therefore been increasingly recognized by industry.In particular,within certain industries that require high reliability,such as the aerospace industry,surface integrity is one of the most relevant indexes used to evaluate the quality of machined parts.Thus,obtaining updated knowledge on surface integrity is of great interest to both the academic community and industry[1].
基金the National Natural Science Foundation of China(No.31971234)the Fundamental Research Funds for the Central Universities(No.20720180045)the Open Research Fund of State Key Laboratory of Cellular Stress Biology,Xiamen University(No.SKLCSB2019KF001)。
文摘Quantum dots(QDs)are new types of nanomaterials.Few studies have focused on the effect of different surface modified QDs on embryonic development.Herein,we compared the in vivo toxicity of Cd Se/Zn S QDs with carboxyl(-COOH)and amino(-NH 2)modification using zebrafish embryos.After exposure,the two Cd Se/Zn S QDs decreased the survival rate,hatching rate,and embryo movement of zebrafish.Moreover,we found QDs attached to the embryo membrane before hatching and the eyes,yolk and heart after hatching.The attached amount of carboxyl QDs was more.Consistently,the Cd content in embryos and larvae was higher in carboxyl QD-treatment.We further observed that the two QDs caused zebrafish pericardial edema and cardiac dysfunction.In line with it,both carboxyl and amino QDs upregulated the transcription levels of cardiac development-related genes,and the levels were higher in carboxyl QD-treated groups.Furthermore,the chelator of Cd^2+diethylene triamine pentacetate acid could partially rescued the developmental toxicity caused by the two types of QDs suggesting that both the nature of QDs and the release of Cd^2+contribute to the developmental toxicity.In conclusion,the two Cd Se/ZnS QDs have developmental toxicity and affect the cardiac development,and the carboxyl QDs is more toxic possibly due to the higher affinity and more release to embryos and larvae.Our study provides new knowledge that the surface functional modification of QDs is critical on the development on aquatic species,which is beneficial to develop and applicate QDs more safely and environmentfriendly.
基金supported by the National Key Technologies Research and Development Program in the Eleventh Five-Year Plan of China (Grant No.2008BAD98B02, 2006BAC01A11)the Western Light Program of Talents Cultivating of CAS (2008)+1 种基金the National Natural Sciences Foundation of China (Grant No. 30470297)the Foundation of Key Laboratory of Mountain Hazards and Surface Process, CAS
文摘Surface morphology of soil cracks is one of the important factors influencing the water evaporation rate in cracked soil in Yuanmou Dry-hot Valley Region,Southwest China. Quantitative study of the complicated surface morphology of soil cracks is a prerequisite for further studies of soil-cracking mechanisms. The present paper establishes a quantitative indicator system by application of concepts and methods originating from Fractal Geometry and Network Analysis. These indicators can effectively express the complicated features of soil-crack network structure. Furthermore,a series of values related to soil-crack morphology was obtained by image processing on field photos of soil-crack quads,and gradation criteria for the degree of development of soil cracks were determined. Finally,the changes in values of the morphological indicators under different degrees of development were analyzed in detail. Our results indicate that (1) the degree of development of soil cracks can be divided into five grades,i.e.,feeble development,slight development,medium development,intensive development and extremely intensive development; (2) the values of the indicators change predictably with increasing degree of development of soil cracks. The area density (Dc) increases,and both the area-weighted mean ratio of crack area to perimeter (AWMARP),which reflects the intensity of cracking,and the index r,which is related to the connectivity of a soil crack,grow uniformly (albeit with different forms). AWMRAP increases at a geometric rate while r shows logarithm-mic growth,indicating a gradual increase in theconnectivity of a soil crack. Nevertheless,the area-weighted mean of soil-crack fractal dimension (AWMFRAC) shows a decreasing trend,indicating a gradual decline in the complexity of cracks as area density increases.
基金supported by the Royal Netherlands Academy of Arts and Sciences(KNAW)(Grant No.PSA-SA-E-02)the Province of Zeeland,the Netherlands(Grant No.CoE-Buitendijks)。
文摘Understanding the sensitivity of tidal flats to environmental changes is challenging.Currently,most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal flats.In this study,we proposed an alternative empirical approach to explore tidal flat dynamics using statistical indices based on long-term time series of daily surface elevation development.Surface elevation dynamic(SED)indices focus on the magnitude and period of surface elevation changes,while morphodynamic signature(MDS)indices relate sediment dynamics to environmental drivers.The statistical analyses were applied to an intervention site in the Netherlands to determine the effect of recently constructed groynes on the tidal flat.Using these analyses,we were able to(1)detect a reduction in the daily SED and(2)determine that the changes in the daily SED were predominantly caused by the reduction in wave impact between the groynes rather than the reduction in tidal currents.Overall,the presented results showed that the combination of novel statistical indices provides new insights into the trajectories of tidal flats,ecosystem functioning,and sensitivity to physical drivers(wind and tides).Finally,we suggested how the SED and MDS indices may help to explore the future trajectories and climate resilience of intertidal habitats.
文摘According to the characteristics of a complex cover panel, its geometry shape is described by the NURBS surface with great description capability. With the reference to the surface classification determined by Gauss curvature, the proportion of the mid-surface area between before and after being developed is derived from the displacement variation of the mid-surface in the normal vector direction of the sheet metal during the sheet metal forming process. Hereby, based on the curve development theory in differential geometry, a novel diagonal point by point surface development method is put forward to estimate a complex cover panel＇s blank contour efficiently. By comparing the sample＇s development result of diagonal point by point surface development method with that of available one-step method, the validity of the proposed surface development method is verified.
基金Under the auspices of National Natural Science Foundation of China(No.42271214,41961027)Key Program of Natural Science Foundation of Gansu Province(No.21JR7RA278,21JR7RA281)+1 种基金the CAS‘Light of West China’Program(No.2020XBZGXBQNXZ-A)Basic Research Top Talent Plan of Lanzhou Jiaotong University(No.2022JC01)。
文摘Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019.
文摘Environmental pollution is a by product of industrialization when economy of a region is developing. China also suffers from such a problem, especially in the southern part like Suzhou region in Jiangsu Province. In this paper, data covering situations of surface water pollution and social and economic development showed that the surface water pollution in Taicang County, a typical economic zone of Suzhou region, is significantly correlated to the economic growth of this region.
文摘Development of curved surface is a useful tool in CAD(computer aided design) and CAGD(computer aided geometric design).This paper presents the algorithms for developing (flattening) a smooth continuous curved surface embedded in three dimensional space into a planar shape. First the definition of planar development of a curved surface is presented, and the distortions (at length and area) of development are discussed in this paper. Then several planar flattening methods of curved surface, and their advantages and disadvantages are analyzed in detail. For NURBS(non uniform rational basic spline) surfaces, which are broadly used in CAGD, we put forward a new planar developing algorithm, i.e. hybrid developing, and present the steps of the algorithm. At last, some examples are used to show the effectiveness of the algorithm.
文摘The rapid growth and early development period of the dual-scale surface topography was studied on the adaxial leaf surfaces of two aspen tree species with non-wetting leaves: the columnar European aspen (Populus tremula “Erecta”) and quaking aspen (Populus tremuloides). Particular attention was focused on the formation of micro- and nano-scale asperities on their cuticles, which was correlated with the development of superhydrophobic wetting behaviour. Measurements of the wetting properties (contact angle and tilt-angle) provided an indication of the degree of hydrophobicity of their cuticles. Scanning electron microscopy and optical profilometry micrographs were used to follow the growth and major morphological changes of micro-scale papillae and nano-scale epicuticular wax (ECW) crystals, which led to a significant improvement in non-wetting behaviour. Both species exhibited syntopism in the form of small and larger nano-scale ECW platelet morphologies. These findings provide additional support for earlier suggestions that due to fluctuations in leaf hydrophobicity throughout the growing season, canopy storage capacity may also vary considerably throughout this time period.
基金the financial support from the Natural Science Foundation of Jilin Province(Project code:20220101212JC)Jilin Province Specific Project of Industrial Technology Research&Development(Project code:2020C025-2)+2 种基金Free Exploration Project of Changsha Automotive Innovation Research Institute of Jilin University(Project code:CAIRIZT20220202)2021"Interdisciplinary Integration and Innovation"Project of Jilin University(Project code:XJRCYB07)Horizon 2020 MSCA(Project code:H2020-MSCA-RISE-778104-ThermaSMART).
文摘To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are used to prepare biomimetic structured surfaces with different wettability.The impingement processes of diesel and n-butanol sprays on the walls under different conditions are experimentally investigated.As the surface oleophilicity increases,the spreading radius of wall-impinging sprays decreases.At about 5 s after the fuel injections,the fuel spray droplets hit the walls for the first time,and the secondary breakup and rebound occur.The mixture concentrations of different fuels hitting the various walls reach the peak value.Under a higher surface temperature,the peak value of the mixture concentration is mainly related to the heat flux to the fuel droplets in different boiling regimes from the metal surfaces.The concentration of the air–fuel mixture in the near wall region increases with increasing surface oleophilicity,increasing wall temperature and decreasing ambient pressure.Compared with diesel,n-butanol presents a higher air–fuel mixture concentration in the near wall region.
