This study discusses the trading behavior of foreign investors with respect to economic uncertainty in the South Korean stock market from a time-varying perspective.We employ a news-based measure of economic uncertain...This study discusses the trading behavior of foreign investors with respect to economic uncertainty in the South Korean stock market from a time-varying perspective.We employ a news-based measure of economic uncertainty along with the model of time-varying parameter vector autoregression with stochastic volatility.The empirical analysis reveals several new findings about foreign investors’trading behaviors.First,we find evidence that positive feedback trading often appears during periods of high economic uncertainty,whereas negative feedback trading is exclusively observable during periods of low economic uncertainty.Second,the foreign investors’feedback trading appears mostly to be well-timed and often leads the time-varying economic uncertainty except in periods of global crises.Third,lagged negative(positive)response of net flows to economic uncertainty is found to be coupled with lagged positive(negative)feedback trading.Fourth,the study documents an asymmetric response of foreign investors with regard to negative and positive shocks of economic uncertainty.Specifically,we find that they instantly turn to positive feedback trading after a negative contemporaneous response of net flows to shocks of economic uncertainty.In contrast,they move slowly toward negative feedback trading after a positive response of net flows to uncertainty shocks.展开更多
A novel design of Return Flow Solar Air Heater(RFSAH)with different arrangements of baffles especially V-Type Artificial roughness is simulated and numerically analyzed with energy balance equations.To enhance the eff...A novel design of Return Flow Solar Air Heater(RFSAH)with different arrangements of baffles especially V-Type Artificial roughness is simulated and numerically analyzed with energy balance equations.To enhance the effectiveness of baffles,numerous studies have been conducted.The performance of the RFSAH is studied in terms of thermal efficiency,thermo-hydraulic efficiency,and optimization of baffle parameters.Maximum Thermal efficiency and thermo-hydraulic efficiency are found in RFSAH with baffle on both sides of the absorber plate and mass flow rate above 0.2kg/s.Sensitivity analysis of the influencing parameters is carried out and reported the best performance of the system on selective geometrical parameters(ψ=0.7,β=20%,e/H=1,p/e=0.8,α=60°).The results obtained from the present model are validated with the published experimental results and have been found in quite reasonable agreement with an average error of 16.45%.Thermal and Thermohydraulic efficiency of RFSAH with a baffle on both sides of the absorber plate is maximum among baffles below,above,and on both sides of the absorber plate.It is observed that the thermal efficiency of RFSAH is greater than SF-SAH.The proposed optimum baffles roughness is suggested to increase the air upholding time period for more efficient output.展开更多
本文以斗式提升机为模型,采用DEM(Discrete Element Method)算法对粉料在提升机内运动过程进行离散元模拟仿真,分析粉料颗粒在其内部的运动轨迹,得出粉料粒径以及料斗数对提升机回料率的影响规律,为提升机的结构优化提出理论性的指导。...本文以斗式提升机为模型,采用DEM(Discrete Element Method)算法对粉料在提升机内运动过程进行离散元模拟仿真,分析粉料颗粒在其内部的运动轨迹,得出粉料粒径以及料斗数对提升机回料率的影响规律,为提升机的结构优化提出理论性的指导。结果表明:(1)均匀粉料粒径越小,机尾回料越严重,并得到回料量与粒径之间的关系式;(2)斗数增加可以提高提升机输送效率,降低粉料回料量;(3)随着粉料粒径的增大,料斗填充率呈现先增大后降低的趋势,并在4 mm粉料粒径时得到峰值,填充率达到69%。展开更多
文摘This study discusses the trading behavior of foreign investors with respect to economic uncertainty in the South Korean stock market from a time-varying perspective.We employ a news-based measure of economic uncertainty along with the model of time-varying parameter vector autoregression with stochastic volatility.The empirical analysis reveals several new findings about foreign investors’trading behaviors.First,we find evidence that positive feedback trading often appears during periods of high economic uncertainty,whereas negative feedback trading is exclusively observable during periods of low economic uncertainty.Second,the foreign investors’feedback trading appears mostly to be well-timed and often leads the time-varying economic uncertainty except in periods of global crises.Third,lagged negative(positive)response of net flows to economic uncertainty is found to be coupled with lagged positive(negative)feedback trading.Fourth,the study documents an asymmetric response of foreign investors with regard to negative and positive shocks of economic uncertainty.Specifically,we find that they instantly turn to positive feedback trading after a negative contemporaneous response of net flows to shocks of economic uncertainty.In contrast,they move slowly toward negative feedback trading after a positive response of net flows to uncertainty shocks.
文摘A novel design of Return Flow Solar Air Heater(RFSAH)with different arrangements of baffles especially V-Type Artificial roughness is simulated and numerically analyzed with energy balance equations.To enhance the effectiveness of baffles,numerous studies have been conducted.The performance of the RFSAH is studied in terms of thermal efficiency,thermo-hydraulic efficiency,and optimization of baffle parameters.Maximum Thermal efficiency and thermo-hydraulic efficiency are found in RFSAH with baffle on both sides of the absorber plate and mass flow rate above 0.2kg/s.Sensitivity analysis of the influencing parameters is carried out and reported the best performance of the system on selective geometrical parameters(ψ=0.7,β=20%,e/H=1,p/e=0.8,α=60°).The results obtained from the present model are validated with the published experimental results and have been found in quite reasonable agreement with an average error of 16.45%.Thermal and Thermohydraulic efficiency of RFSAH with a baffle on both sides of the absorber plate is maximum among baffles below,above,and on both sides of the absorber plate.It is observed that the thermal efficiency of RFSAH is greater than SF-SAH.The proposed optimum baffles roughness is suggested to increase the air upholding time period for more efficient output.
文摘本文以斗式提升机为模型,采用DEM(Discrete Element Method)算法对粉料在提升机内运动过程进行离散元模拟仿真,分析粉料颗粒在其内部的运动轨迹,得出粉料粒径以及料斗数对提升机回料率的影响规律,为提升机的结构优化提出理论性的指导。结果表明:(1)均匀粉料粒径越小,机尾回料越严重,并得到回料量与粒径之间的关系式;(2)斗数增加可以提高提升机输送效率,降低粉料回料量;(3)随着粉料粒径的增大,料斗填充率呈现先增大后降低的趋势,并在4 mm粉料粒径时得到峰值,填充率达到69%。
