Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and deriva...Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and derivatives offers exciting opportunities to optimize the device performance while poses theoretical challenges to quantify their electrochemical behavior as required for molecular design.Computational screening of target quinones with high performance is far from satisfactory.While solvation of quinones affects their potential application in RFBs in terms of both electrochemical windows,stability,and charge transport,experimental data for the solvation structure and solvation free energies are rarely available if not incomplete.Besides,conventional thermodynamic models are mostly unreliable to estimate the properties of direct interest for electrochemical applications.Here,we analyze the hydration free energies of more than 1,400 quinones by combining the first-principles calculations and the classical density functional theory.In order to attain chemical insights and possible trends,special attention is placed on the effects of"backbones"and functional groups on the solvation behavior.The theoretical results provide a thermodynamic basis for the design,synthesis,and screening of high-performance catholytes for electrical energy storage.展开更多
目的探讨宁神止痉汤对颅内动脉瘤破裂所致蛛网膜下腔出血(aneurysmal subarachnoid hemorrhage,aSAH)介入术后脑血管痉挛患者脑损伤、自由基、脑血流及神经功能的影响。方法选取治疗的aSAH患者80例,随机分为对照组与研究组,每组40例,患...目的探讨宁神止痉汤对颅内动脉瘤破裂所致蛛网膜下腔出血(aneurysmal subarachnoid hemorrhage,aSAH)介入术后脑血管痉挛患者脑损伤、自由基、脑血流及神经功能的影响。方法选取治疗的aSAH患者80例,随机分为对照组与研究组,每组40例,患者给予尼莫地平等药物常规治疗,研究组在对照组治疗基础上给予宁神止痉汤口服治疗,治疗时间14 d,观察患者治疗前后血清神经元特异性烯醇化酶(neuron specific enolase,NSE)、星形胶质源性蛋白(astroglia-derived protein,S100β)、超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)、内皮素-1(endothelin-1,ET-1)、一氧化氮(nitric oxide,NO)变化,大脑中动脉平均血流速度(median cerebral artery velocity,Vm)、脑血管痉挛指数(linde-gard)、血管自我调节功能指标脉冲指数(impulse index of vascular self-regulation function,PI)变化,采用格拉斯哥(Glasgow coma scale,GCS)和美国国立卫生研究院卒中量表(National Institutes of Health Stroke Scale,NIHSS)评分对患者神经功能状况进行评价。结果两组患者治疗前血清NSE及S100β水平比较差异无统计学意义(P>0.05),治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05);两组患者治疗前血清SOD、MDA、ET-1、NO水平比较差异无统计学意义(P>0.05),MDA、ET-1治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05),SOD、NO治疗后较治疗前升高(P<0.05),且研究组升高程度大于对照组(P<0.05),比较差异有统计学意义(P<0.05);两组患者治疗前大脑中动脉Vm、linde-gard、PI比较差异无统计学意义(P>0.05),治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05);两组患者治疗前血清GCS及NIHSS评分比较差异无统计学意义(P>0.05),NIHSS治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05),GCS治疗后较治疗前升高(P<0.05),且研究组升高程度大于对照组(P<0.05)。结论aSAH介入术后脑血管痉挛患者采用宁神止痉汤治疗,可有助于减轻脑损伤,降低自由基,改善脑血流,促进神经功能的恢复。展开更多
In this paper,based on the imaginary time gradient flow model in the density functional theory,a scalar auxiliary variable(SAV)method is developed for the ground state calculation of a given electronic structure syste...In this paper,based on the imaginary time gradient flow model in the density functional theory,a scalar auxiliary variable(SAV)method is developed for the ground state calculation of a given electronic structure system.To handle the orthonormality constraint on those wave functions,two kinds of penalty terms are introduced in designing the modified energy functional in SAV,i.e.,one for the norm preserving of each wave function,another for the orthogonality between each pair of different wave functions.A numerical method consisting of a designed scheme and a linear finite element method is used for the discretization.Theoretically,the desired unconditional decay of modified energy can be obtained from our method,while computationally,both the original energy and modified energy decay behaviors can be observed successfully from a number of numerical experiments.More importantly,numerical results show that the orthonormality among those wave functions can be automatically preserved,without explicitly preserving orthogonalization operations.This implies the potential of our method in large-scale simulations in density functional theory.展开更多
Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow w...Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow water turbines in open channels as an undershot type after removing the casings and guide vanes to substantially simplify these water turbines. However, because undershot cross-flow water turbines are designed on the basis of cross-flow water turbine runners used in typical pipelines, it remains unclear whether the number of blades has an effect on the performance or flow fields. Thus, in this research, experiments and numerical analyses are employed to study the performance and flow fields of undershot cross-flow water turbines with varying number of blades. The findings show that the turbine output and torque are lower, the fluctuation is significantly higher, and the turbine efficiency is higher for runners with 8 blades as opposed to those with 24 blades.展开更多
基金supported by the National Natural Science Foundation of China(U1862204)the U.S.National Science Foundation(NSF-1940118)。
文摘Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and derivatives offers exciting opportunities to optimize the device performance while poses theoretical challenges to quantify their electrochemical behavior as required for molecular design.Computational screening of target quinones with high performance is far from satisfactory.While solvation of quinones affects their potential application in RFBs in terms of both electrochemical windows,stability,and charge transport,experimental data for the solvation structure and solvation free energies are rarely available if not incomplete.Besides,conventional thermodynamic models are mostly unreliable to estimate the properties of direct interest for electrochemical applications.Here,we analyze the hydration free energies of more than 1,400 quinones by combining the first-principles calculations and the classical density functional theory.In order to attain chemical insights and possible trends,special attention is placed on the effects of"backbones"and functional groups on the solvation behavior.The theoretical results provide a thermodynamic basis for the design,synthesis,and screening of high-performance catholytes for electrical energy storage.
文摘目的探讨宁神止痉汤对颅内动脉瘤破裂所致蛛网膜下腔出血(aneurysmal subarachnoid hemorrhage,aSAH)介入术后脑血管痉挛患者脑损伤、自由基、脑血流及神经功能的影响。方法选取治疗的aSAH患者80例,随机分为对照组与研究组,每组40例,患者给予尼莫地平等药物常规治疗,研究组在对照组治疗基础上给予宁神止痉汤口服治疗,治疗时间14 d,观察患者治疗前后血清神经元特异性烯醇化酶(neuron specific enolase,NSE)、星形胶质源性蛋白(astroglia-derived protein,S100β)、超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)、内皮素-1(endothelin-1,ET-1)、一氧化氮(nitric oxide,NO)变化,大脑中动脉平均血流速度(median cerebral artery velocity,Vm)、脑血管痉挛指数(linde-gard)、血管自我调节功能指标脉冲指数(impulse index of vascular self-regulation function,PI)变化,采用格拉斯哥(Glasgow coma scale,GCS)和美国国立卫生研究院卒中量表(National Institutes of Health Stroke Scale,NIHSS)评分对患者神经功能状况进行评价。结果两组患者治疗前血清NSE及S100β水平比较差异无统计学意义(P>0.05),治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05);两组患者治疗前血清SOD、MDA、ET-1、NO水平比较差异无统计学意义(P>0.05),MDA、ET-1治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05),SOD、NO治疗后较治疗前升高(P<0.05),且研究组升高程度大于对照组(P<0.05),比较差异有统计学意义(P<0.05);两组患者治疗前大脑中动脉Vm、linde-gard、PI比较差异无统计学意义(P>0.05),治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05);两组患者治疗前血清GCS及NIHSS评分比较差异无统计学意义(P>0.05),NIHSS治疗后较治疗前下降(P<0.05),且研究组下降程度大于对照组(P<0.05),GCS治疗后较治疗前升高(P<0.05),且研究组升高程度大于对照组(P<0.05)。结论aSAH介入术后脑血管痉挛患者采用宁神止痉汤治疗,可有助于减轻脑损伤,降低自由基,改善脑血流,促进神经功能的恢复。
基金The first author would like to thank the support from the UM-Funded PhD Assistantship from University of MacaoThe second author was partially supported by Macao Young Scholar Program(AM201919)+5 种基金excellent youth project of Hunan Education Department(19B543)Hunan National Applied Mathematics Center of Hunan Provincial Science and Technology Department(2020ZYT003)The third author would like to thank financial support from National Natural Science Foundation of China(Grant Nos.11922120,11871489)FDCT of Macao SAR(Grant No.0082/2020/A2)University of Macao(Grant No.MYRG2020-00265-FST)Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications(Grant No.2020B1212030001).
文摘In this paper,based on the imaginary time gradient flow model in the density functional theory,a scalar auxiliary variable(SAV)method is developed for the ground state calculation of a given electronic structure system.To handle the orthonormality constraint on those wave functions,two kinds of penalty terms are introduced in designing the modified energy functional in SAV,i.e.,one for the norm preserving of each wave function,another for the orthogonality between each pair of different wave functions.A numerical method consisting of a designed scheme and a linear finite element method is used for the discretization.Theoretically,the desired unconditional decay of modified energy can be obtained from our method,while computationally,both the original energy and modified energy decay behaviors can be observed successfully from a number of numerical experiments.More importantly,numerical results show that the orthonormality among those wave functions can be automatically preserved,without explicitly preserving orthogonalization operations.This implies the potential of our method in large-scale simulations in density functional theory.
文摘Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow water turbines in open channels as an undershot type after removing the casings and guide vanes to substantially simplify these water turbines. However, because undershot cross-flow water turbines are designed on the basis of cross-flow water turbine runners used in typical pipelines, it remains unclear whether the number of blades has an effect on the performance or flow fields. Thus, in this research, experiments and numerical analyses are employed to study the performance and flow fields of undershot cross-flow water turbines with varying number of blades. The findings show that the turbine output and torque are lower, the fluctuation is significantly higher, and the turbine efficiency is higher for runners with 8 blades as opposed to those with 24 blades.
