Toroidal Multipolar Expansion for Fast L-Mode Plasma Boundary Reconstruction in EAST

A new method for plasma boundary reconstruction, based on the toroidal multipolar expansion （TME） scheme, is applied successfully in EAST. TME applies a limited number of toroidal multipolar moments based on toroidal coordinates to treat a two-dimensional problem of axisymmetric plasma equilibrium. The plasma boundary reconstructed by TME is consistent with the results by using EFIT. The method is sufficiently reliable and fast for real time shape control.

Alteration of Excitatory Amino Acid in Experimen-tal Spinal Cord Injury in Rats

Objective To detect the effect of excitatory ammo add (EAA) in the secondary damage following spinal cord injury (SCI). Methods Glutamate (Glu) and Aspartate (Asp) on the injury site (T8) were studied using a rat SCI model induced by Allen's weight drop method (10g×2. 5cm). The result suggested that Asp and Glu were significantly increased in 10 mm. Results Glu was significantly decreased from 2 h to 24 h,while Asp was a tittle reduced in 2 h,and slightly rose in 4 h as compared with Control Group. Though elevated in 8 h,it dropped again in 24h as compared with Control Group. Conclusion The result indicates that the rise of EAA following SCI could be the cause of the secondary spinal cord damage.

Urban Physics： Effect of the micro-climate on comfort, health and energy demand

The global trend towards urbanisation explains the growing interest in the study of the modification of the urban climate due to the heat island effect and global warming, and its impact on enersy use of buildings. Also urban comfort, health and durability, referring respectively to pedestrian wind/ thermal comfort, pollutant dispersion and wind-driven rain are of interest. Urban Physics is a well- established discipline, incorporating relevant branches of physics, environmental chemistry, aerodynamics, meteorolosy and statistics. Therefore, Urban Physics is well positioned to provide keycontributions to the current urban problems and challenges. The present paper addresses the role of Urban Physics in the study of wind comfort, thermal comfort, energy demand, pollutant dispersion and wind-driven rain. Furthermore, the three major research methods applied in Urban Physics, namely field experiments, wind tunnel experiments and numerical simulations are discussed. Case studies illustrate the current challenges and the relevant contributions of Urban Physics.

The effects of vertical viscosity coefficients with different distribution characteristics on classical Ekman spiral structure

The classical Ekman theory tells us that the ocean surface current turns to the right(left) side of wind direction with 45° in the north(south) hemisphere,but the observation and research results show that the surface current deflexion angle is smaller than 45° in the Arctic and high latitude areas while larger than 45° in the low latitude areas.In order to explain these phenomena,a series of idealized numerical experiments are designed to investigate the influence of vertical viscosity coefficients with different vertical distribution characteristics on the classical and steady Ekman spiral structure.Results show that when the vertical viscosity coefficient decreases with water depth,the surface current deflexion angle is larger than 45°,whereas the angle is smaller than 45° when the vertical viscosity coefficient increases with water depth.So the different observed surface current deflexion angles in low latitude sea areas and the Arctic regions should be attributed to the different vertical distribution characteristics of vertical viscosity coefficients in the upper ocean.The flatness of the Ekman spiral is not equal to one and does not show regular behaviors for the numerical experiments with different distribution of vertical viscosity.However,the magnitudes and directions of volume transport of Ekman spirals are almost the same as the results of classical Ekman theory,i.e.,vertical viscosity coefficient distributions have no effect on the magnitudes and directions of volume transport.

Scallop ice shape characteristics of swept wing based on large-scale icing wind tunnel experiment

Scallop ice is a special phenomenon that occurs during swept wing aircraft passing through icing clouds.It poses a great challenge for the icing safety assessment that the complex scallop ice shape feature and its mechanism are still unclear.In this work,a large-scale icing wind tunnel experiment of swept wing designed by NACA0012 airfoil is conducted in the Icing Wind Tunnel of China Aerodynamics Research and Development Center.The detailed three-dimensional ice shapes under 0°,15°,30°and 45°swept angles are obtained by laser scanning technology.The experimental results show that with the swept angle increasing from 0°to 45°,the 2D double ice horn structures show certain spanwise variation,and finally transform into complete scallop ice with ice thickness greatly enhanced in the stagnation line region.The empirical mode decomposition of the spanwise ice curve captures the high-frequency fluctuation on the scallop ice caused by the small-scale roughness element,while the trend with low frequency is not obvious.Based on the experimental data,a new complete scallop ice geometric model,named 5Points-5Lines-2Arcs(5P-5L-2A)model,is proposed,which can provide important basis for the quantitative description of complex scallop ice shape.

Competition mechanism of multiple four-wave mixing in highly nonlinear fiber： spatial instability and satellite characteristics

Competition mechanism in multiple four-wave mixing （MFWM） processes is demonstrated theoretically. Provided considering only two waves injected into a highly nonlinear fiber （HNLF）, there are three modes displaying comprehensive dynamic behaviors, such as fixed points, periodic motion, and chaotic motion. Especially, Mode C of MFWM is emphasized by analyzing its phase-space trajectory to demonstrate nonlinear wave- wave interactions. The study shows that, when the phase- space trajectory approaches or gets through a saddle point, a dramatic power depletion for the injected wave can be realized, with the representative point moving chaotically, but when phase-space trajectories are distributed around a center point, the power for the injected wave is retained almost invariable, with the representative point moving periodically. Finally, the evolvement of satellite wave over an optical fiber is investigated by comparing it with the interference pattern in Young＇s double-slit experiment.