平井 直志

上級研究員(研究院講師)

  • 758 引用
  • 14 h指数
1993 …2020

年単位の研究成果

Pureに変更を加えた場合、すぐここに表示されます。

研究成果

フィルター
Conference contribution
2019

Broadband Far-infrared Spectroscopic Identification and Quantification of Antioxidants in Polymeric Insulation

Ogishima, T., Kozai, T., Hirai, N. & Ohki, Y., 2019 2 13, ICHVE 2018 - 2018 IEEE International Conference on High Voltage Engineering and Application. Institute of Electrical and Electronics Engineers Inc., 8641948. (ICHVE 2018 - 2018 IEEE International Conference on High Voltage Engineering and Application).

研究成果: Conference contribution

1 引用 (Scopus)

Degradation in Dielectric Behavior of Soft Epoxy Resin by Concurrent Aging with Heat and Radiation

Ishii, H., Yamaguchi, H., Mori, K., Hirai, N. & Ohki, Y., 2019 10, 2019 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2019 - Proceedings. Institute of Electrical and Electronics Engineers Inc., p. 18-21 4 p. 9010557. (Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP; 巻数 2019-October).

研究成果: Conference contribution

Degradation in Mechanical and Dielectric Properties of Silicone Rubber under Severe Aging Conditions

Hirai, N., Kaneko, T., Ito, S., Minakawa, T. & Ohki, Y., 2019 10, 2019 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2019 - Proceedings. Institute of Electrical and Electronics Engineers Inc., p. 126-129 4 p. 9009713. (Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP; 巻数 2019-October).

研究成果: Conference contribution

Degradation of silicone rubber analyzed by instrumental analyses and dielectric spectroscopy

Ohki, Y., Hirai, N., Min, D., Yang, L. & Li, S., 2019 1 1, Minerals, Metals and Materials Series. Springer International Publishing, p. 1323-1332 10 p. (Minerals, Metals and Materials Series).

研究成果: Conference contribution

1 引用 (Scopus)

Evaluation of Aging Status of Flame-retardant Cross-linked Polyethylene by Measuring Indenter Modulus

Yang, Z., Hirai, N. & Ohki, Y., 2019 4, ICEMPE 2019 - 2nd International Conference on Electrical Materials and Power Equipment, Proceedings. Institute of Electrical and Electronics Engineers Inc., p. 57-60 4 p. 8727348. (ICEMPE 2019 - 2nd International Conference on Electrical Materials and Power Equipment, Proceedings).

研究成果: Conference contribution

1 引用 (Scopus)

Origins of Chemiluminescence in Polymeric Insulating Materials

Ohki, Y., Fujishima, D., Okamoto, M. & Hirai, N., 2019 4, ICEMPE 2019 - 2nd International Conference on Electrical Materials and Power Equipment, Proceedings. Institute of Electrical and Electronics Engineers Inc., p. 12-16 5 p. 8727389. (ICEMPE 2019 - 2nd International Conference on Electrical Materials and Power Equipment, Proceedings).

研究成果: Conference contribution

1 引用 (Scopus)

Relation between the Glass Transition and Dielectric Properties in Bisphenol A and F Epoxy Resins

Mori, K., Hirai, N., Ohki, Y., Otake, Y., Umemoto, T. & Muto, H., 2019 10, 2019 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2019 - Proceedings. Institute of Electrical and Electronics Engineers Inc., p. 426-429 4 p. 9010555. (Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP; 巻数 2019-October).

研究成果: Conference contribution

Successful detection of insulation degradation in cables by frequency domain reflectometry

Ohki, Y. & Hirai, N., 2019 1 1, Minerals, Metals and Materials Series. Springer International Publishing, p. 1293-1301 9 p. (Minerals, Metals and Materials Series).

研究成果: Conference contribution

2018

Aging State Analysis of Safety-related Cables for Nuclear Power Plants Exposed to Simulated Accident Conditions

Minakawa, T., Ikeda, M., Hirai, N. & Ohki, Y., 2018 11 26, 2018 IEEE CEIDP Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2018. Institute of Electrical and Electronics Engineers Inc., 巻 2018-October. p. 602-605 4 p. 8544872

研究成果: Conference contribution

2 引用 (Scopus)

Degradation behavior and mechanisms of several polymeric insulating materials exposed to heat and radiation

Yang, L., Ohki, Y., Hirai, N. & Li, S., 2018 2 2, 2017 3rd International Conference on Condition Assessment Techniques in Electrical Systems, CATCON 2017 - Proceedings. Institute of Electrical and Electronics Engineers Inc., 巻 2018-January. p. 98-103 6 p.

研究成果: Conference contribution

Degradation of silicone rubber analyzed by instrumental analyses and dielectric spectroscopy

Ohki, Y., Hirai, N., Min, D., Yang, L. & Li, S., 2018 1 1, Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems – Water Reactors. Springer International Publishing, p. 107-116 10 p. (Minerals, Metals and Materials Series; 巻数 Part F11).

研究成果: Conference contribution

Effects of Heat and Radiation Aging and Burning on the Surface Physical Properties of Polymer-Insulated Cables

Ito, S., Hirai, N., Minakawa, T., Kuroda, C. & Ohki, Y., 2018 11 26, 2018 IEEE CEIDP Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2018. Institute of Electrical and Electronics Engineers Inc., 巻 2018-October. p. 374-377 4 p. 8544768

研究成果: Conference contribution

1 引用 (Scopus)

Effects of Heat and Radiation on the Terahertz Absorption in Silicone Rubber

Kaneko, T., Hirai, N. & Ohki, Y., 2018 9 19, 2018 IEEE 2nd International Conference on Dielectrics, ICD 2018. Institute of Electrical and Electronics Engineers Inc., p. 223DUMMY 8470044

研究成果: Conference contribution

1 引用 (Scopus)

Location Attempt of Multiple Heated Spots in a Polymer-insulated Coaxial Cable by Frequency Domain Reflectometry

Hirai, N. & Ohki, Y., 2018 11 14, 2018 Condition Monitoring and Diagnosis, CMD 2018 - Proceedings. Abu-Siada, A. (版). Institute of Electrical and Electronics Engineers Inc., 8535734

研究成果: Conference contribution

2 引用 (Scopus)

Similarity in degradation behavior by heat and irradiation between ethylene-propylene-diene rubber and silicone rubber

Ohki, Y., Kotani, H., Fujishima, D. & Hirai, N., 2018 1 12, CEIDP 2017 - IEEE Conference on Electrical Insulation and Dielectric Phenomenon. Institute of Electrical and Electronics Engineers Inc., 巻 2017-October. p. 157-160 4 p.

研究成果: Conference contribution

2 引用 (Scopus)

Successful detection of insulation degradation in cables by frequency domain reflectometry

Ohki, Y. & Hirai, N., 2018 1 1, Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems – Water Reactors. Springer International Publishing, p. 77-85 9 p. (Minerals, Metals and Materials Series; 巻数 Part F11).

研究成果: Conference contribution

2 引用 (Scopus)

Terahertz time-domain spectroscopic analyses on crystallinity of several organic polymers

Ohki, Y., Azeyanagi, C., Kaneko, T. & Hirai, N., 2018 6 29, ICPADM 2018 - 12th International Conference on the Properties and Applications of Dielectric Materials. Institute of Electrical and Electronics Engineers Inc., 巻 2018-May. p. 86-89 4 p.

研究成果: Conference contribution

2017

Correlation between indenter modulus and elongation-at-break observed for four electrical insulating polymers

Hirai, N. & Ohki, Y., 2017 12 4, Proceedings of 2017 International Symposium on Electrical Insulating Materials, ISEIM 2017. Institute of Electrical Engineers of Japan, 巻 2. p. 753-756 4 p.

研究成果: Conference contribution

4 引用 (Scopus)

Effects of addition of MgO fillers with various sizes and co-addition of nano-sized SiO2 fillers on the dielectric properties of epoxy resin

Yanashima, R., Hirai, N. & Ohki, Y., 2017 12 4, Proceedings of 2017 International Symposium on Electrical Insulating Materials, ISEIM 2017. Institute of Electrical Engineers of Japan, 巻 2. p. 650-653 4 p.

研究成果: Conference contribution

4 引用 (Scopus)

Improved high-temperature dielectric property of epoxy resin composites with nano- and micro-sized magnesia fillers

Xie, Q., Ohki, Y., Hirai, N. & Cheng, Y. H., 2017 5 31, 2017 IEEE International Workshop on Integrated Power Packaging, IWIPP 2017. Institute of Electrical and Electronics Engineers Inc., 7936745

研究成果: Conference contribution

1 引用 (Scopus)

Insulation performance of safety-related cables for nuclear power plants under simulated severe accident conditions

Minakawa, T., Ikeda, M., Hirai, N. & Ohki, Y., 2017 12 4, Proceedings of 2017 International Symposium on Electrical Insulating Materials, ISEIM 2017. Institute of Electrical Engineers of Japan, 巻 2. p. 716-719 4 p.

研究成果: Conference contribution

1 引用 (Scopus)

Terahertz absorption spectra of antioxidants in insulating polymers

Kozai, T., Kaneko, T., Hirai, N. & Ohki, Y., 2017 10 27, Proceedings of 2017 International Symposium on Electrical Insulating Materials, ISEIM 2017. Institute of Electrical Engineers of Japan, p. 61-64 4 p. (Proceedings of the International Symposium on Electrical Insulating Materials; 巻数 1).

研究成果: Conference contribution

Terahertz absorption spectroscopy of poly(ether ether ketone)

Kaneko, T., Hirai, N. & Ohki, Y., 2017 12 4, Proceedings of 2017 International Symposium on Electrical Insulating Materials, ISEIM 2017. Institute of Electrical Engineers of Japan, 巻 2. p. 539-542 4 p.

研究成果: Conference contribution

3 引用 (Scopus)
2016

Aging mechanism of silicone rubber by heat and gamma-rays

Ohki, Y., Hanada, S., Miyamoto, M., Hirai, N. & Yang, L., 2016 12 15, 2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2016. Institute of Electrical and Electronics Engineers Inc., 巻 2016-December. p. 869-872 4 p. 7785487

研究成果: Conference contribution

6 引用 (Scopus)

Chemiluminescence characteristics of FR-EPDM and SiR aged by concurrently-given heat and radiation

Ikeno, R., Hirai, N. & Ohki, Y., 2016 12 15, 2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2016. Institute of Electrical and Electronics Engineers Inc., 巻 2016-December. p. 853-856 4 p. 7785443

研究成果: Conference contribution

3 引用 (Scopus)

Comparison of location abilities of degradation in a polymer-insulated cable between frequency domain reflectometry and line resonance analysis

Ohki, Y. & Hirai, N., 2016 12 27, ICHVE 2016 - 2016 IEEE International Conference on High Voltage Engineering and Application. Institute of Electrical and Electronics Engineers Inc., 7800602

研究成果: Conference contribution

1 引用 (Scopus)

Fault location in a cable for a nuclear power plant by frequency domain reflectometry

Ohki, Y. & Hirai, N., 2016 11 28, CMD 2016 - International Conference on Condition Monitoring and Diagnosis. Institute of Electrical and Electronics Engineers Inc., p. 36-39 4 p. 7757782

研究成果: Conference contribution

9 引用 (Scopus)

Non-destructive diagnosis of degradation of silicone rubber by indenter modulus and scanning probe microscopy

Hanada, S., Odaka, D., Yang, L., Hirai, N. & Ohki, Y., 2016 11 28, CMD 2016 - International Conference on Condition Monitoring and Diagnosis. Institute of Electrical and Electronics Engineers Inc., p. 123-126 4 p. 7757791

研究成果: Conference contribution

3 引用 (Scopus)

Space charge distributions in epoxy/MgO nanocomposites at various temperatures

Xie, Q., Cheng, Y. H., Hirai, N. & Ohki, Y., 2016 12 27, ICHVE 2016 - 2016 IEEE International Conference on High Voltage Engineering and Application. Institute of Electrical and Electronics Engineers Inc., 7800636

研究成果: Conference contribution

7 引用 (Scopus)

Terahertz spectroscopic diagnosis of degradation of ethylene-propylene-diene copolymer

Ohki, Y., Kozai, T., Komatsu, M. & Hirai, N., 2016 8 18, Proceedings of the 2016 IEEE International Conference on Dielectrics, ICD 2016. Institute of Electrical and Electronics Engineers Inc., 巻 2. p. 646-649 4 p. 7547698

研究成果: Conference contribution

2015

Influence of cable structure on the fault location by frequency domain reflectometry

Ohki, Y. & Hirai, N., 2015 12 9, Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP. Institute of Electrical and Electronics Engineers Inc., 巻 2015-December. p. 274-277 4 p. 7352023

研究成果: Conference contribution

6 引用 (Scopus)
2014

Chemiluminescence due to oxidation of ethylene propylene diene copolymers

Ohki, Y. & Hirai, N., 2014 12 22, 2014 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2014. Institute of Electrical and Electronics Engineers Inc., p. 425-428 4 p. 6995786

研究成果: Conference contribution

3 引用 (Scopus)

Highly sensitive detection of distorted points in a cable by frequency domain reflectometry

Hirai, N. & Ohki, Y., 2014 1 1, Proceedings of 2014 International Symposium on Electrical Insulating Materials, ISEIM 2014. Institute of Electrical Engineers of Japan, p. 144-147 4 p. 6870741. (Proceedings of the International Symposium on Electrical Insulating Materials).

研究成果: Conference contribution

10 引用 (Scopus)
2013

Highly sensitive location method of an abnormal temperature point in a cable by frequency domain reflectometry

Ohki, Y., Hirai, N., Yamada, T. & Kumagai, S., 2013 12 1, ICSD 2013 - Proceedings of the 2013 IEEE International Conference on Solid Dielectrics. p. 117-120 4 p. 6619799. (Proceedings of IEEE International Conference on Solid Dielectrics, ICSD).

研究成果: Conference contribution

5 引用 (Scopus)
2012

Chemiluminescence as a clear diagnostic tool of polymer oxidation

Ohki, Y. & Hirai, N., 2012 11 26, ICPADM 2012 - 2012 IEEE 10th International Conference on the Properties and Applications of Dielectric Materials, Technical Papers. 6318953. (Proceedings of the IEEE International Conference on Properties and Applications of Dielectric Materials).

研究成果: Conference contribution

4 引用 (Scopus)

Comparison of broadband impedance spectroscopy and time domain reflectometry for locating cable degradation

Hirai, N., Yamada, T. & Ohki, Y., 2012 12 1, Proceedings of 2012 IEEE International Conference on Condition Monitoring and Diagnosis, CMD 2012. p. 229-232 4 p. 6416417. (Proceedings of 2012 IEEE International Conference on Condition Monitoring and Diagnosis, CMD 2012).

研究成果: Conference contribution

18 引用 (Scopus)

Improvement in sensitivity of broadband impedance spectroscopy for locating degradation in cable insulation by ascending the measurement frequency

Yamada, T., Hirai, N. & Ohki, Y., 2012 12 1, Proceedings of 2012 IEEE International Conference on Condition Monitoring and Diagnosis, CMD 2012. p. 677-680 4 p. 6416236. (Proceedings of 2012 IEEE International Conference on Condition Monitoring and Diagnosis, CMD 2012).

研究成果: Conference contribution

13 引用 (Scopus)
2008

Need for condition monitoring and diagnosis of electric wires and cables used in nuclear power plants

Ohki, Y., Hirai, N. & Yamamoto, T., 2008 1 1, Proceedings of 2008 International Conference on Condition Monitoring and Diagnosis, CMD 2008. IEEE Computer Society, p. 1207-1211 5 p. 4580505. (Proceedings of 2008 International Conference on Condition Monitoring and Diagnosis, CMD 2008).

研究成果: Conference contribution

4 引用 (Scopus)
2006

Dielectric properties of biodegradable polymers

Ohki, Y. & Hirai, N., 2006 12 1, 2006 Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP. p. 668-671 4 p. 4105521. (Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP).

研究成果: Conference contribution

9 引用 (Scopus)
2004

Dielectric properties of biodegradable polylactic acid and starch ester

Hirai, N., Maeno, Y., Tamura, H., Kaneko, D., Tanaka, T., Ohki, Y., Tajitsu, Y., Kohtoh, M. & Okabe, S., 2004 1 1, Proceedings of the 2004 IEEE International Conference on Solid Dielectrics ICSD 2004. Institute of Electrical and Electronics Engineers Inc., p. 87-90 4 p. 1P-12. (Proceedings of the 2004 IEEE International Conference on Solid Dielectrics ICSD 2004; 巻数 1).

研究成果: Conference contribution

14 引用 (Scopus)
1993

Measurement of hole mobility in dielectric liquids

Hirai, N., Arii, K., Kikuchi, H., Masoaka, T. & Nitanada, H., 1993 12 1, Proceedings of the 11th International Conference on Conduction and. Publ by IEEE, p. 101-105 5 p. (Proceedings of the 11th International Conference on Conduction and).

研究成果: Conference contribution