Hidefumi Nishinaka

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We precisely evaluated a single-chip 10-V programmable Josephson voltage standard (PJVS) system based on a closed-cycle refrigerator by directly comparing it with a conventional Josephson voltage standard system. The PJVS chip fabricated using NbN/TiN<sub>x</sub>/NbN junction technology was used. The result of the measurement showed a good agreement with a(More)
Study of the quantized Hall effect as a resistance standard at ETL is in progress. The quantized Hall resistances (QHR's) have been measured using AlGaAs/GaAs modulation doped (MD) structures, that have been made at ETL, and Si-MOSFET's. The measurements were carried out at magnetic fields of 7 T for a GaAs sample (i = 2) and 15 T for a Si sample (i = 4) at(More)
We measured variations of output voltages of four Zener standards (Fluke732B) with change of environmental conditions such as humidity, temperature and pressure. Four Zener standards have negligibly small humidity characteristics. The characteristic of the temperature was the order of 0.01 ppm/K. The characteristic of the pressure was approximately 0.02(More)
We have been operating a 10-V programmable Josephson voltage standard (PJVS) system that was developed based on a multi-chip technique. We compared the PJVS with an SIS-based conventional JVS indirectly using a zener diode. The results agreed within 10<sup>-8</sup> level.
We investigated temperature dependencies of Zener-diode voltage reference standards. Some Zeners showed output voltage differences between ac line power and battery operation, and the voltage differences were related to the oven temperature change in the Zeners. A waiting time of five hours was suggested when the Zener was operated by the battery.
We developed a 10-V dc programmable Josephson voltage standard (PJVS) using a multichip technique. The PJVS was based on NbN/TiN<sub>x</sub>/NbN junctions and operated using a 10-K compact cryocooler. We carried out an indirect comparison with a superconductor-insulator-superconductor-based conventional Josephson voltage standard (JVS) by measuring the(More)
We report the International System (SI) value of the quantized Hall resistance (R<inf>H</inf>) determined by using a calculable capacitor at the electrotechnical laboratory (ETL). As the result of our measurements at ETL, a most reliable value of h / e<sup>2</sup> has been estimated as 25 812.8036 &#x03A9;<inf>SI</inf> with a systematic uncertainty of 0.25(More)
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