Pentaquark Magnetic Moments In Different Models

We calculate the magnetic moments of the pentaquark states from different models and compare our results with predictions of other groups.Comment: 17 pages, no figur

Observation of Magnetization Processes in Soft Magnetic Composite

A magneto-optical imaging technique has been employed to visualize magnetization processes of soft magnetic composite material. The profiles of reflected light intensity of magneto-optical images at the sample surface were plotted. The results demonstrate that magnetooptical imaging is a sensitive tool to visualize magnetization process. The flux profiles obtained under conditions of perpendicular and tangential magnetizations indicate that the sample behaves as a collection of individual magnetized particles rather than as a uniform and continuous magnetic substance

A data assimilation method of the Ensemble Kalman Filter for use in severe dust storm forecasts over China

International audienceAn Ensemble Kalman Filter (EnKF) data assimilation system was developed for a regional dust transport model. This paper applied the EnKF method to investigate modeling severe dust storm episodes occurred in March 2002 over China based on surface observations of dust concentrations to explore its impacts on forecast improvement. A series of sensitivity experiments using our system reveals that the EnKF is an advanced assimilation method to afford better initial conditions with surface observed PM10 in North China and lead to improved forecasts of dust storms, but forecast with large errors can be made by model errors. This result illustrates that it requires identifying and correcting model errors during the assimilation procedure in order to significantly improve forecasts. Results also show that the EnKF should use a large inflation parameter to obtain better model performance and forecast potential. Furthermore, the ensemble perturbations generated at the initial time should include enough ensemble spreads to represent the background error after several assimilation cycles

Magnetic Moments of JP=3/2+J^P={3/2}^+ Pentaquarks

If the $J^P$ of $\Theta_5^+$ and $\Xi_5^{--}$ pentaquarks is really found to be ${1\over 2}^+$ by future experiments, they will be accompanied by $J^P={3\over 2}^+$ partners in some models. It is reasonable to expect that these $J^P={3\over 2}^+$ states will also be discovered in the near future with the current intensive experimental and theoretical efforts. We estimate $J^P={3/2}^+$ pentaquark magnetic moments using different models.Comment: 13 page

Heavy Pentaquarks

We construct the spin-flavor wave functions of the possible heavy pentaquarks containing an anti-charm or anti-bottom quark using various clustered quark models. Then we estimate the masses and magnetic moments of the $J^P={1\over 2}^+$ or ${3\over 2}^+$ heavy pentaquarks. We emphasize the difference in the predictions of these models. Future experimental searches at BESIII, CLEOc, BELLE, and LEP may find these interesting states

An Ensemble Kalman Filter for severe dust storm data assimilation over China

International audienceAn Ensemble Kalman Filter (EnKF) data assimilation system was developed for a regional dust transport model. This paper applied the EnKF method to investigate modeling of severe dust storm episodes occurring in March 2002 over China based on surface observations of dust concentrations to explore the impact of the EnKF data assimilation systems on forecast improvement. A series of sensitivity experiments using our system demonstrates the ability of the advanced EnKF assimilation method using surface observed PM10 in North China to correct initial conditions, which leads to improved forecasts of dust storms. However, large errors in the forecast may arise from model errors (uncertainties in meteorological fields, dust emissions, dry deposition velocity, etc.). This result illustrates that the EnKF requires identification and correction model errors during the assimilation procedure in order to significantly improve forecasts. Results also show that the EnKF should use a large inflation parameter to obtain better model performance and forecast potential. Furthermore, the ensemble perturbations generated at the initial time should include enough ensemble spreads to represent the background error after several assimilation cycles

Strong light-induced negative optical pressure arising from the kinetic energy of conduction electrons in plasmonic cavities

We found that very strong negative optical pressure can be induced in plasmonic cavities by LC resonance. This interesting effect could be described qualitatively by a Lagrangian model which shows that the negative optical pressure is driven by the internal inductance and the kinetic energy of the conduction electrons. If the metal is replaced by perfect conductors, the optical pressure becomes much smaller and positive.Comment: 18 pages, 8 figure

A miniature short stroke linear actuator - Design and analysis

We report a newly developed miniature short stroke tubular linear permanent-magnet actuator for robotic applications. Compared to a rotary-to-linear mechanism, the linear actuator has the advantages of efficiency, thrust control, and compact size in generating linear motion. We optimized the electromagnetic force of the actuator analytically by selecting appropriate dimensions and then predicted the force produced by the winding currents by the finite-element method under the brushless dc excitation scheme. We analyzed the actuation performance by dynamic modeling of the actuator. We constructed and tested a prototype on a specially designed test bench to verify the design. Finally, we analyzed and measured the end effect on the magnetic force due to the limited length of the stator core and translator.Compared with the rotary-to-linear mechanism, linear actuators show advantages in terms of efficiency, thrust control, and system volume when linear motion is required. This paper presents the design and analysis of a newly developed miniature short stroke tubular linear permanent-magnet actuator for robotic applications. The electromagnetic force of the actuator was optimized analytically by selecting appropriate dimensions. The force produced by the winding currents was then predicted by the finite-element method under the brushless dc excitation scheme. The actuation performance was also analyzed through the dynamic modeling of the actuator. A prototype was constructed and tested on a specially designed test bench to verify the design. Moreover, the end effect on the magnetic force due to the limited length of the stator core and translator was analyzed and measured. © 2006 IEEE