Abstract: Herein disclosed are an electrochemical method for determining the end point of oxidation-reduction reactions, certain exchange reactions or precipitation reactions of organic or inorganic compounds and a dipole gold electrode used therein. The method comprises immersing a pair of electrodes or an electrode having a gold sensing portion and detecting and analyzing variations in electrical potential or current observed during the reaction. The electrode comprises a tube having a closed bottom, a pair of gold members passed through and projected outside the tube, a pair of terminals disposed at the top of the tube and a pair of metal elements electrically connecting the gold members and the terminals. This method and the electrode makes it possible to effectively determine the end point of the reaction with high accuracy and good reproducibility.

Abstract: A digital frequency display device for digitally displaying the operating frequency of a communication apparatus comprising a reference frequency oscillator, a first frequency mixer for mixing the output frequencies of a first oscillator of the communication apparatus and of the reference frequency oscillator, a second frequency mixer for mixing the output frequency of a second oscillator of the communication apparatus and the resultant frequency provided from the first frequency mixer to produce the display frequency shifted by the reference frequency, and a frequency counter for counting the output frequency from the second frequency mixer and for correcting the shifted frequency component to display the correct frequency.

Abstract: A digital frequency display device includes a counter for counting a frequency to be displayed, a latch circuit for temporarily storing a plurality of digit signals from the counter and for outputting the digit signals in response to the latch pulses, a decoder for decoding the digit signals from the latch circuit into another coding system, a display section for visually displaying the digit signals decoded from the decoder, a gate for preventing the latch pulses from reaching the latch circuit at undesired times and a digit eraser for erasing any one of the digits of the numerals representing the frequency displayed when the latch pulses feeding to the latch circuit is blocked by the gate means.

Abstract: A gas shielding method for a fuel exchange pool in which, in order to shield radioactive gas generated in said fuel exchange pool by forming a gas curtain flowing in one direction above the fuel pool, both a ratio between a blown-out quantity and a sucked quantity of the gas flow and a temperature difference between the gas and the water in the fuel pool are suitably selected.

Abstract: A digital frequency display device for digitally displaying the operating frequency of a communication apparatus comprising a reference frequency oscillator, a first frequency mixer for mixing the output frequencies of a first oscillator of the communication apparatus and of the reference frequency oscillator, a second frequency mixer for mixing the output frequency of a second oscillator of the communication apparatus and the resultant frequency provided from the first frequency mixer to produce the display frequency shifted by the reference frequency, and a frequency counter for counting the output frequency from the second frequency mixer and for correcting the shifted frequency component to display the correct frequency.