The data of the year 1992 from 25 geomagnetic observatories affiliated to the geomagnetic network of State Seismological Bureau of China were processed using the principle of geomagnetic spatial gradient method. Throu...The data of the year 1992 from 25 geomagnetic observatories affiliated to the geomagnetic network of State Seismological Bureau of China were processed using the principle of geomagnetic spatial gradient method. Through finding out the polynomial form of optimum fitting, comparatively good C values for four harmonic components of diurnal variations were obtained. By using the inverse method of non linear underdetermined problem, the electrical conductivity structures under the observatories were investgated. It is shown that there are differences of the C values and conductivity structures in the deep underground under the south western part and northern parts and other parts of China. We studied the possibility of improving the gradient method for investigation of the deep underground conductivity structure, and it is indicated that the gradient method is hopeful in the investigation of earth′s deep conductivity structure and the applied studies concerned.展开更多
For characterizing a series augmented railgun launching process,the simulation and experiment were done.In the experiment,only observation of muzzle voltage,current and armature position were insufficient to analyze l...For characterizing a series augmented railgun launching process,the simulation and experiment were done.In the experiment,only observation of muzzle voltage,current and armature position were insufficient to analyze launching process deeply since armature velocity,resistance force and voltage drop of armature were also important to the launching process.In the present work,based on MATLAB/SIMULINK software platform,the simulation model was built,and the dynamic characteristics of system were simulated.Furthermore,the variations of armature velocity,total resistance force and voltage drop of armature against time were investigated based on the data of B-dot probes(to measure position of armature),Rogowsky coil(to monitor current) and high voltage probes(to observe muzzle voltage).The results indicated that,the voltage drop of armature and the total resistance force showed roughly regulartendency.There were obvious stages observed in the two-turn series augmented railgun launching process.展开更多
文摘The data of the year 1992 from 25 geomagnetic observatories affiliated to the geomagnetic network of State Seismological Bureau of China were processed using the principle of geomagnetic spatial gradient method. Through finding out the polynomial form of optimum fitting, comparatively good C values for four harmonic components of diurnal variations were obtained. By using the inverse method of non linear underdetermined problem, the electrical conductivity structures under the observatories were investgated. It is shown that there are differences of the C values and conductivity structures in the deep underground under the south western part and northern parts and other parts of China. We studied the possibility of improving the gradient method for investigation of the deep underground conductivity structure, and it is indicated that the gradient method is hopeful in the investigation of earth′s deep conductivity structure and the applied studies concerned.
文摘For characterizing a series augmented railgun launching process,the simulation and experiment were done.In the experiment,only observation of muzzle voltage,current and armature position were insufficient to analyze launching process deeply since armature velocity,resistance force and voltage drop of armature were also important to the launching process.In the present work,based on MATLAB/SIMULINK software platform,the simulation model was built,and the dynamic characteristics of system were simulated.Furthermore,the variations of armature velocity,total resistance force and voltage drop of armature against time were investigated based on the data of B-dot probes(to measure position of armature),Rogowsky coil(to monitor current) and high voltage probes(to observe muzzle voltage).The results indicated that,the voltage drop of armature and the total resistance force showed roughly regulartendency.There were obvious stages observed in the two-turn series augmented railgun launching process.
