Abstract: A flux containing 1 to 10 wt % of an organic sulfonic acid activator, 10 to 40 wt % of a high-molecular-weight nonionic surfactant that is a nonionic surfactant having a mass-average molecular weight Mw of more than 1200 and 5 to 75 wt % of a low-molecular-weight nonionic surfactant that is a nonionic surfactant having a mass-average molecular weight Mw of 1200 or less, in which the content of the low-molecular-weight nonionic surfactant is equal to or larger than the content of the organic sulfonic acid activator. This flux contains no cationic surfactant or contains more than 0 wt % and 5 wt % or less of the cationic surfactant. A solder paste containing this flux and a Sn-based solder metal.

Abstract: An apparatus for detecting position/variance of input light is disclosed which includes a photoelectric conversion device receiving input light constituted of a first resistive layer formed of a first photoelectric conversion material and a second resistive layer formed of a second photoelectric conversion material connected with the first resistive layer through a depletion layer or directly, wherein the first resistive layer is provided with uniform resistivity throughout its surface so that a linear output proportional to the average of the distances between one end of the photoelectric conversion device and positions of the input light is detected and the second resistive layer is provided with resistivity dependent upon the distance from its one end so that a quandratic ouput proportional to the average of the squares of the distances between one end of the photoelectric conversion device and positions of the input light is detected.

Abstract: A method and an apparatus of ultrasonic flaw detection suitable for detecting internal cavern defects of a material, the method involving the mounting on a rotary body of a plural number of skew probes in equidistant positions in the circumferential direction of the rotary body to provide a corresponding number of channels for transmitting and receiving ultrasonic beams in a direction intersecting the axis of rotation of the rotary body at different depths in an inspection zone of a material positioned opposingly to the probes. The rotary body is turned to revolve the probes through 360.degree. about the axis of rotation while transmitting and receiving the ultrasonic pulses. Selected flaw patterns are produced from the peak values of the echoes received at the detection gates of the respective channels in relation with the direction of incidence of the ultrasonic beams.