This letter presents a method for visualizing the 2-dimensional distribution of electrostatic charge, which is based on the principle of the X-ray CT. For confirming the possibility of this method, the focusing images of the simple model are also demonstrated by a computer computation.

For the effectively therapeutic conditions of laser acupuncture, as a first step, this letter examines the thermal stress inside the skin tissue produced by laser acupuncture. A method is presented of calculating the 3-dimensional thermal stress. The numerical results are also shown.

This letter describes the occurrence-frequencies of the microarcs in the carbon sliding-contacts which are known to give the low radio-noises. A method is presented for statistically evaluating the arc occurrence-frequencies. The measurement results are also shown.

This letter presents a method for estimating the discontact rate by the pantograph noise current using a statistical test. This method requires no apriori information on the current collection system used in the previous methods. The experiment is performed to verify the validity of the above method.

This letter presents a method for real-time visualization of static electricity distribution which can be achieved by rapidly measuring the voltages induced on the array electrodes. For verifying the validity of this method, the measurement examples on the charged sheets are demonstrated.