The study aimed to discuss the application of CINRAD/SA radar using negative elevation angle mode in observation of tropical cyclone. Firstly, the calculation formula of the lowest detecting height of CINRAD/SA radar ...The study aimed to discuss the application of CINRAD/SA radar using negative elevation angle mode in observation of tropical cyclone. Firstly, the calculation formula of the lowest detecting height of CINRAD/SA radar was educed, and then the application of negative angle mode in Changle Radar Station was introduced. Through analyzing different observing abilities for tropical cyclone detected at different elevation angles, we discussed the limitation of CINRAD/SA radar using negative angle mode, and finally proposed some suggestions on CINRAD/SA radar using nega- tive elevation angle mode to observe tropical cyclone.展开更多
Background:Post-mortem and magnetic resonance imaging(MRI)studies of the central sulcus,as an indicator of motor cortex,have shown that in the general population there is greater representation of the dominant compare...Background:Post-mortem and magnetic resonance imaging(MRI)studies of the central sulcus,as an indicator of motor cortex,have shown that in the general population there is greater representation of the dominant compared to the non-dominant hand.Studies of musicians,who are highly skilled in performing complex finger movements,have suggested this dominance is affected by musical training,but methods and findings have been mixed.Objective:In the present study,an automated image analysis pipeline using a 3D mesh approach was applied to measure central sulcus(CS)asymmetry on MR images obtained for a cohort of right-handed pianists and matched controls.Methods:The depth,length,and surface area(SA)of the CS and thickness of the cortical mantle adjacent to the CS were measured in each cerebral hemisphere by applying the BrainVISA Morphologist 2012 software pipeline to 3D T1-weighted MR images of the brain obtained for 15 right-handed pianists and 14 controls,matched with respect to age,sex,and handedness.Asymmetry indices(AIs)were calculated for each parameter and multivariate analysis of covariance(MANCOVA),and post hoc tests were performed to compare differences between the pianist and control groups.Results:A one-way MANCOVA across the four AIs,controlling for age and sex,revealed a significant main effect of group(P=0.04),and post hoc analysis revealed that while SA was significantly greater in the left than the right cerebral hemisphere in controls(P<0.001),there was no significant difference between left and right SA in the pianists(P=0.634).Independent samples t-tests revealed that the SA of right CS was significantly larger in pianists compared to controls(P=0.015),with no between-group differences in left CS.Conclusions:Application of an image analysis pipeline to 3D MR images has provided robust evidence of sig-nificantly increased representation of the non-dominant hand in the brain of pianists compared to age-,sex-,and handedness-matched controls.This finding supports prior research showing structural differences in the central sulcus in musicians and is interpreted to reflect the long-term motor training and high skill level of right-handed pianists in using their left hand.展开更多
现代战争要求战斗机能够在大迎角(AOA)状态下进行过失速飞行,对飞机大迎角绕流流场的研究主要的方法有风洞试验和数值模拟。在大迎角风洞试验中,常用的是尾支撑方法,支架的存在会对模型的试验结果产生一定的影响,本文通过数值模拟来对...现代战争要求战斗机能够在大迎角(AOA)状态下进行过失速飞行,对飞机大迎角绕流流场的研究主要的方法有风洞试验和数值模拟。在大迎角风洞试验中,常用的是尾支撑方法,支架的存在会对模型的试验结果产生一定的影响,本文通过数值模拟来对这个影响进行研究。以开源计算流体力学软件OpenFOAM 2.3为平台,采用PIMPLE算法求解Navier-Stokes(N-S)方程,PIMPLE算法是SIMPLE(Semi-Implicit Method for Pressure-linked Equations)算法和PISO(Pressure Implicit with Splitting of Operator)算法的结合体;采用基于有限体积的空间离散方法和空间二阶精度的线性插值方法,时间离散采用后向差分方法,湍流模型采用SA-DDES(Spalart-Allmaras-Delayed Detached Eddy Simulation)模型。为了验证方法的可靠性,首先对0°、10°、30°、50°、70°以及90°迎角下的有支架三角翼绕流流场进行计算,并将计算结果与试验结果进行对比,两者吻合较好。在此基础上,数值模拟了无支架的三角翼绕流流场,对比有/无支架情况下数值模拟结果,得到支架对三角翼绕流流场、背风面压强分布和气动力的影响。计算结果表明:大迎角情况下,有支架与无支架时相比,支架的存在会影响三角翼附近的流场(但是不会改变涡系等流动结构)、改变翼表面压强分布,从而导致三角翼的法向力系数和俯仰力矩系数发生明显变化。展开更多
文摘The study aimed to discuss the application of CINRAD/SA radar using negative elevation angle mode in observation of tropical cyclone. Firstly, the calculation formula of the lowest detecting height of CINRAD/SA radar was educed, and then the application of negative angle mode in Changle Radar Station was introduced. Through analyzing different observing abilities for tropical cyclone detected at different elevation angles, we discussed the limitation of CINRAD/SA radar using negative angle mode, and finally proposed some suggestions on CINRAD/SA radar using nega- tive elevation angle mode to observe tropical cyclone.
基金Research assistance from Dr.Emma Moore and funding from the European Commission under the Marie Curie Intra-European Fellowship Programme(EC FP7-2010-PEOPLE-IEF 276529)the Marie Curie Action Networks for Initial Training(EC PITN-GA-2009-238157-EBRAMUS)the Society for Education,Music and Psychology Research(SEMPRE)and by the Reid School of Music,Edinburgh College of Art,University of Edinburgh is gratefully acknowledged.
文摘Background:Post-mortem and magnetic resonance imaging(MRI)studies of the central sulcus,as an indicator of motor cortex,have shown that in the general population there is greater representation of the dominant compared to the non-dominant hand.Studies of musicians,who are highly skilled in performing complex finger movements,have suggested this dominance is affected by musical training,but methods and findings have been mixed.Objective:In the present study,an automated image analysis pipeline using a 3D mesh approach was applied to measure central sulcus(CS)asymmetry on MR images obtained for a cohort of right-handed pianists and matched controls.Methods:The depth,length,and surface area(SA)of the CS and thickness of the cortical mantle adjacent to the CS were measured in each cerebral hemisphere by applying the BrainVISA Morphologist 2012 software pipeline to 3D T1-weighted MR images of the brain obtained for 15 right-handed pianists and 14 controls,matched with respect to age,sex,and handedness.Asymmetry indices(AIs)were calculated for each parameter and multivariate analysis of covariance(MANCOVA),and post hoc tests were performed to compare differences between the pianist and control groups.Results:A one-way MANCOVA across the four AIs,controlling for age and sex,revealed a significant main effect of group(P=0.04),and post hoc analysis revealed that while SA was significantly greater in the left than the right cerebral hemisphere in controls(P<0.001),there was no significant difference between left and right SA in the pianists(P=0.634).Independent samples t-tests revealed that the SA of right CS was significantly larger in pianists compared to controls(P=0.015),with no between-group differences in left CS.Conclusions:Application of an image analysis pipeline to 3D MR images has provided robust evidence of sig-nificantly increased representation of the non-dominant hand in the brain of pianists compared to age-,sex-,and handedness-matched controls.This finding supports prior research showing structural differences in the central sulcus in musicians and is interpreted to reflect the long-term motor training and high skill level of right-handed pianists in using their left hand.
文摘现代战争要求战斗机能够在大迎角(AOA)状态下进行过失速飞行,对飞机大迎角绕流流场的研究主要的方法有风洞试验和数值模拟。在大迎角风洞试验中,常用的是尾支撑方法,支架的存在会对模型的试验结果产生一定的影响,本文通过数值模拟来对这个影响进行研究。以开源计算流体力学软件OpenFOAM 2.3为平台,采用PIMPLE算法求解Navier-Stokes(N-S)方程,PIMPLE算法是SIMPLE(Semi-Implicit Method for Pressure-linked Equations)算法和PISO(Pressure Implicit with Splitting of Operator)算法的结合体;采用基于有限体积的空间离散方法和空间二阶精度的线性插值方法,时间离散采用后向差分方法,湍流模型采用SA-DDES(Spalart-Allmaras-Delayed Detached Eddy Simulation)模型。为了验证方法的可靠性,首先对0°、10°、30°、50°、70°以及90°迎角下的有支架三角翼绕流流场进行计算,并将计算结果与试验结果进行对比,两者吻合较好。在此基础上,数值模拟了无支架的三角翼绕流流场,对比有/无支架情况下数值模拟结果,得到支架对三角翼绕流流场、背风面压强分布和气动力的影响。计算结果表明:大迎角情况下,有支架与无支架时相比,支架的存在会影响三角翼附近的流场(但是不会改变涡系等流动结构)、改变翼表面压强分布,从而导致三角翼的法向力系数和俯仰力矩系数发生明显变化。
