Preparation of high purity 110 K phase in the (Bi, Pb)-Sr-Ca-Cu-O superconductor system using a solution method

A solution method has been demonstrated to purify the 110 K superconducting phase in the (Bi, Pb)-Sr-Ca-Cu-O system. Oxalic acid was used to chelate metal cations from the nitrates. The amount of chelating agent impacts the cation absorption in the precursor. The higher purity 110 K superconducting phase can be obtained in the shortest time and at the lowest sintering temperature. X-ray diffraction, resistivity and magnetization measurements all indicated positive evidence. The process can be expedited when the stoichiometry was enriched by calcium and copper. The preparation technique is considered valuable to purify multi-phase superconductors for mass production.     

A novel device for head gesture measurement system in combination with eye-controlled human–machine interface

This study describes the design and combination of an eye-controlled and a head-controlled human–machine interface system. This system is a highly effective human–machine interface, detecting head movement by changing positions and numbers of light sources on the head. When the users utilize the head-mounted display to browse a computer screen, the system will catch the images of the user's eyes with CCD cameras, which can also measure the angle and position of the light sources. In the eye-tracking system, the program in the computer will locate each center point of the pupils in the images, and record the information on moving traces and pupil diameters. In the head gesture measurement system, the user wears a double-source eyeglass frame, so the system catches images of the user's head by using a CCD camera in front of the user. The computer program will locate the center point of the head, transferring it to the screen coordinates, and then the user can control the cursor by head motions. We combine the eye-controlled and head-controlled human–machine interface system for the virtual reality applications.