The thermodynamic properties of boron nitride under extreme pressures and temperatures are of great interest and importance for materials science and inertial confinement fusion physics,but they are poorly understood ...The thermodynamic properties of boron nitride under extreme pressures and temperatures are of great interest and importance for materials science and inertial confinement fusion physics,but they are poorly understood owing to the challenges of performing experiments and realizing ab initio calculations.Here,we report the first shock Hugoniot data on hexagonal boron nitride at pressures of 5–16 Mbar,using hohlraum-driven shock waves at the SGIII-p laser facility in China.Our density functional theory molecular dynamics calculations closely match experimental data,validating the equations of state for modeling the shock response of boron nitride and filling a crucial gap in the knowledge of boron nitride properties in the region of multi-Mbar pressures and eV temperatures.The results presented here provide fundamental insights into boron nitride under the extreme conditions relevant to inertial confinement fusion,hydrogen–boron fusion,and high-energy-density physics.展开更多
The coastal areas of the lower reaches of Oujiang River Basin are rich in groundwater resources.However,the unsustainable exploitation and utilization of groundwater have led to significant changes in the groundwater ...The coastal areas of the lower reaches of Oujiang River Basin are rich in groundwater resources.However,the unsustainable exploitation and utilization of groundwater have led to significant changes in the groundwater environment.Understanding the characteristics and genesis of groundwater salinization is crucial for preventing its deterioration and ensuring sustainable utilization.In this study,a comprehensive approach combining the ion ratio method,mineral saturation index method and multivariate statistical analysis was employed to investigate the hydrochemical characteristics and main controlling factors in the study area.The findings reveal that:(1)Groundwater samples in study area exhibit a neutral to slightly alkaline pH.The predominant chemical types of unconfined water are HCO_(3)-Ca·Na,HCO_(3)·Cl-Na·Ca and HCO_(3)·SO_(4)-Ca·Na,while confined water mainly exhibits Cl·HCO_(3)-Na and Cl-Na types.(2)Salinity coefficients indicate an increase in salinity from unconfined to confined water.TDS,Na^(+)and Cl^(–)concentrations show an increasing trend from mountainous to coastal areas in unconfined water,while confined water displays variability in TDS,Na^(+)and Cl^(–)concentrations.(3)Groundwater salinity is mainly influenced by water-rock interactions,including the dissolution of halite and gypsum,cation exchange,and seawater intrusion etc.Additionally,human activities and carbonate dissolution contribute to salinity in unconfined water.Seawater intrusion is identified as the primary factor leading to higher salinity in confined water compared to unconfined water,with increasing cation exchange and seawater interaction observed from unconfined to confined water.展开更多
直流式整流罩空调在夏季高温、高湿、高盐雾环境中,存在制冷量有台阶、热工影响因素多、受环境影响大、响应特性差等问题,对此展开分析,提出了比例积分微分(Proportion-al Integral Derivative,PID)控制、温湿度解耦、制冷量台阶处理等...直流式整流罩空调在夏季高温、高湿、高盐雾环境中,存在制冷量有台阶、热工影响因素多、受环境影响大、响应特性差等问题,对此展开分析,提出了比例积分微分(Proportion-al Integral Derivative,PID)控制、温湿度解耦、制冷量台阶处理等空调控制策略,并对其进行试验验证,结果表明该措施有效。采用该控制策略对航天器进行环境保障,满足航天器对火箭整流罩内的温湿度要求。展开更多
春季发芽期(Timing of spring bud flush,TBF)是茶树重要的农艺性状,对茶叶的风味品质和经济效益均具有重要的影响。为了挖掘调控茶树TBF性状的关键候选基因,以龙井43×白毫早杂交的F1群体327株子代为材料,利用基于该群体构建的茶...春季发芽期(Timing of spring bud flush,TBF)是茶树重要的农艺性状,对茶叶的风味品质和经济效益均具有重要的影响。为了挖掘调控茶树TBF性状的关键候选基因,以龙井43×白毫早杂交的F1群体327株子代为材料,利用基于该群体构建的茶树高密度遗传图谱,采用MapQTL 6.0和GACD 1.2软件对茶树春季发芽指数(Sprouting indexs,SPI)进行数量性状基因座(QTL)定位。连续两年(2022、2023年)对群体子代的春季SPI进行观测,结果显示,SPI在F1群体内存在明显的性状分离,表现出数量性状的特征。利用MapQTL6.0软件定位到1个主效的QTL(qSPI-5-1),分别可解释18.30%(2022年)和7.60%(2023年)的表型变异;利用GACD1.2软件定位到2个稳定的QTL位点(qSPI-1,qSPI-5-2),解释2.75%~18.40%的表型变异,且qSPI-5-2与qSPI-5-1位点基本重合。进一步将上述3个位点的置信区间与茶树参考基因组进行比对,通过基因功能注释分析共筛选到23个与调控茶树春季发芽期相关的候选基因。研究结果为进一步探究茶树春季萌发的调控基因和分子机理提供了理论参考。展开更多
The influence of pre-aging treatment on the microstructure,texture and mechanical properties of the Mg–6Zn–1Gd–1Er(wt.%)alloy was investigated.The microstructure analysis shows that the presence of pre-aging is ben...The influence of pre-aging treatment on the microstructure,texture and mechanical properties of the Mg–6Zn–1Gd–1Er(wt.%)alloy was investigated.The microstructure analysis shows that the presence of pre-aging is beneficial to{1012}twin nucleation at the early stage of extrusion and inhibits the growth of twins and promotes the formation of[1010]-fiber texture components,thus accelerating the complex process of recrystallization.In the middle stage of extrusion,the extruded samples under the condition of solid solution were subjected to dynamic precipitation during severe shear deformation.The precipitation of the second phase particles followed the particle stimulating nucleation(PSN)mechanism,which increased the volume fraction of DRX grains during extrusion.In the extruded samples under the peak-aged condition,the particles appear dissolved during the severe shear deformation strain,which slows down the DRX process.In the later stage of extrusion,the small rod-shaped particles followed the PSN mechanism,and finally formed the strong fiber texture.The extruded alloy exhibits the strongest mechanical properties under the peak-aged state,with ultimate tensile strength(UTS)of 346 MPa,tensile yield strength(TYS)of 217 MPa,and elongation to failure(EL)of 13.6%.The improvement of mechanical properties is mainly attributed to the existence of strong fiber texture,small rod-shaped and block-shaped phases.展开更多
The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture ...The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture the relationship between mining and other equilibrium elements.This study presents an innovative evaluation method to assess the water level recovery resulting from mining reduction based on the relationship between variation in exploitation and recharge.Firstly,the recharge variability of source and sink terms for both the base year and evaluation year is calculated and the coefficient of recharge variationβis introduced,which is then used to calculate the effective mining reduction and solve the water level recovery value caused by the effective mining reduction,and finally the water level recovery contribution by mining reduction is calculated by combining with the actual volume of mining reduction in the evaluation area.This research focuses on Baoding and Shijiazhuang Plain area,which share similar hydrogeological conditions but vary in groundwater exploitation and utilization.As the effect of groundwater level recovery with mining reduction was evaluated in these two areas as case study.In 2018,the results showed an effective water level recovery of 0.17 m and 0.13 m in the shallow groundwater of Shijiazhuang and Baoding Plain areas,respectively.The contributions of recovery from mining reduction were 76%and 57.98%for these two areas,respectively.It was notable that the water level recovery was most prominent in the foothill plain regions.From the evaluation results,it is evident that water level recovery depends not only on the intensity of groundwater mining reduction,but also on its effectiveness.The value of water level recovery alone cannot accurately indicate the intensity of mining reduction,as recharge variation significantly influences water level changes.Therefore,in practice,it is crucial to comprehensively assess the impact of mining reduction on water level recovery by combining the coefficient of recharge variation with the contribution of water level recovery from mining reduction.This integrated approach provide a more reasonable and scientifically supported basis,offering essential data support for groundwater management and conservation.To improve the accuracy and reliability of evaluation results,future work will focus on the standardizing and normalizing raw data processing.展开更多
文摘The thermodynamic properties of boron nitride under extreme pressures and temperatures are of great interest and importance for materials science and inertial confinement fusion physics,but they are poorly understood owing to the challenges of performing experiments and realizing ab initio calculations.Here,we report the first shock Hugoniot data on hexagonal boron nitride at pressures of 5–16 Mbar,using hohlraum-driven shock waves at the SGIII-p laser facility in China.Our density functional theory molecular dynamics calculations closely match experimental data,validating the equations of state for modeling the shock response of boron nitride and filling a crucial gap in the knowledge of boron nitride properties in the region of multi-Mbar pressures and eV temperatures.The results presented here provide fundamental insights into boron nitride under the extreme conditions relevant to inertial confinement fusion,hydrogen–boron fusion,and high-energy-density physics.
基金supported by investigation project of China Geological Survey(DD20230507).
文摘The coastal areas of the lower reaches of Oujiang River Basin are rich in groundwater resources.However,the unsustainable exploitation and utilization of groundwater have led to significant changes in the groundwater environment.Understanding the characteristics and genesis of groundwater salinization is crucial for preventing its deterioration and ensuring sustainable utilization.In this study,a comprehensive approach combining the ion ratio method,mineral saturation index method and multivariate statistical analysis was employed to investigate the hydrochemical characteristics and main controlling factors in the study area.The findings reveal that:(1)Groundwater samples in study area exhibit a neutral to slightly alkaline pH.The predominant chemical types of unconfined water are HCO_(3)-Ca·Na,HCO_(3)·Cl-Na·Ca and HCO_(3)·SO_(4)-Ca·Na,while confined water mainly exhibits Cl·HCO_(3)-Na and Cl-Na types.(2)Salinity coefficients indicate an increase in salinity from unconfined to confined water.TDS,Na^(+)and Cl^(–)concentrations show an increasing trend from mountainous to coastal areas in unconfined water,while confined water displays variability in TDS,Na^(+)and Cl^(–)concentrations.(3)Groundwater salinity is mainly influenced by water-rock interactions,including the dissolution of halite and gypsum,cation exchange,and seawater intrusion etc.Additionally,human activities and carbonate dissolution contribute to salinity in unconfined water.Seawater intrusion is identified as the primary factor leading to higher salinity in confined water compared to unconfined water,with increasing cation exchange and seawater interaction observed from unconfined to confined water.
文摘直流式整流罩空调在夏季高温、高湿、高盐雾环境中,存在制冷量有台阶、热工影响因素多、受环境影响大、响应特性差等问题,对此展开分析,提出了比例积分微分(Proportion-al Integral Derivative,PID)控制、温湿度解耦、制冷量台阶处理等空调控制策略,并对其进行试验验证,结果表明该措施有效。采用该控制策略对航天器进行环境保障,满足航天器对火箭整流罩内的温湿度要求。
文摘春季发芽期(Timing of spring bud flush,TBF)是茶树重要的农艺性状,对茶叶的风味品质和经济效益均具有重要的影响。为了挖掘调控茶树TBF性状的关键候选基因,以龙井43×白毫早杂交的F1群体327株子代为材料,利用基于该群体构建的茶树高密度遗传图谱,采用MapQTL 6.0和GACD 1.2软件对茶树春季发芽指数(Sprouting indexs,SPI)进行数量性状基因座(QTL)定位。连续两年(2022、2023年)对群体子代的春季SPI进行观测,结果显示,SPI在F1群体内存在明显的性状分离,表现出数量性状的特征。利用MapQTL6.0软件定位到1个主效的QTL(qSPI-5-1),分别可解释18.30%(2022年)和7.60%(2023年)的表型变异;利用GACD1.2软件定位到2个稳定的QTL位点(qSPI-1,qSPI-5-2),解释2.75%~18.40%的表型变异,且qSPI-5-2与qSPI-5-1位点基本重合。进一步将上述3个位点的置信区间与茶树参考基因组进行比对,通过基因功能注释分析共筛选到23个与调控茶树春季发芽期相关的候选基因。研究结果为进一步探究茶树春季萌发的调控基因和分子机理提供了理论参考。
基金the financial supports from the National Natural Science Foundation of China(Grant No.51975207&51404079)Hunan Provincial Natural Science Foundation for Excellent Young Scholars of China(Grant No.2019JJ30010)Guangdong Provincial Department of Science and Technology(Grant No.2014B010105009,No.2015A030313902)。
文摘The influence of pre-aging treatment on the microstructure,texture and mechanical properties of the Mg–6Zn–1Gd–1Er(wt.%)alloy was investigated.The microstructure analysis shows that the presence of pre-aging is beneficial to{1012}twin nucleation at the early stage of extrusion and inhibits the growth of twins and promotes the formation of[1010]-fiber texture components,thus accelerating the complex process of recrystallization.In the middle stage of extrusion,the extruded samples under the condition of solid solution were subjected to dynamic precipitation during severe shear deformation.The precipitation of the second phase particles followed the particle stimulating nucleation(PSN)mechanism,which increased the volume fraction of DRX grains during extrusion.In the extruded samples under the peak-aged condition,the particles appear dissolved during the severe shear deformation strain,which slows down the DRX process.In the later stage of extrusion,the small rod-shaped particles followed the PSN mechanism,and finally formed the strong fiber texture.The extruded alloy exhibits the strongest mechanical properties under the peak-aged state,with ultimate tensile strength(UTS)of 346 MPa,tensile yield strength(TYS)of 217 MPa,and elongation to failure(EL)of 13.6%.The improvement of mechanical properties is mainly attributed to the existence of strong fiber texture,small rod-shaped and block-shaped phases.
基金supported by National Natural Science Foundation of China(41972262)Hebei Natural Science Foundation for Excellent Young Scholars(D2020504032).
文摘The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture the relationship between mining and other equilibrium elements.This study presents an innovative evaluation method to assess the water level recovery resulting from mining reduction based on the relationship between variation in exploitation and recharge.Firstly,the recharge variability of source and sink terms for both the base year and evaluation year is calculated and the coefficient of recharge variationβis introduced,which is then used to calculate the effective mining reduction and solve the water level recovery value caused by the effective mining reduction,and finally the water level recovery contribution by mining reduction is calculated by combining with the actual volume of mining reduction in the evaluation area.This research focuses on Baoding and Shijiazhuang Plain area,which share similar hydrogeological conditions but vary in groundwater exploitation and utilization.As the effect of groundwater level recovery with mining reduction was evaluated in these two areas as case study.In 2018,the results showed an effective water level recovery of 0.17 m and 0.13 m in the shallow groundwater of Shijiazhuang and Baoding Plain areas,respectively.The contributions of recovery from mining reduction were 76%and 57.98%for these two areas,respectively.It was notable that the water level recovery was most prominent in the foothill plain regions.From the evaluation results,it is evident that water level recovery depends not only on the intensity of groundwater mining reduction,but also on its effectiveness.The value of water level recovery alone cannot accurately indicate the intensity of mining reduction,as recharge variation significantly influences water level changes.Therefore,in practice,it is crucial to comprehensively assess the impact of mining reduction on water level recovery by combining the coefficient of recharge variation with the contribution of water level recovery from mining reduction.This integrated approach provide a more reasonable and scientifically supported basis,offering essential data support for groundwater management and conservation.To improve the accuracy and reliability of evaluation results,future work will focus on the standardizing and normalizing raw data processing.
