1.

論文(リポジトリ)

論文(リポジトリ)
藤井, 岳 ; 土田, 龍太郎 ; 與儀, 護 ; 辺土, 正人 ; 仲間, 隆男 ; Fujii, Gaku ; Tsuchida, Ryutaro ; Yogi, Mamoru ; Hedo, Masato ; Nakama, Takao
出版情報: 琉球大学教職センター紀要 = Bulletin of Center for Professional Development of Teachers.  pp.141-148,  2021-03-31.  琉球大学教職センター
URL: http://hdl.handle.net/20.500.12000/48021
概要: 新型コロナウィルス感染対策のため,理学部物理系の専門実験科目の授業をICTを使い遠隔で行った.一部の実験課題は動画を配信し,その動画で実験データを学生自ら取得する遠隔実験を行った. 遠隔実験について学生にアンケートを取った結果,動画による実 験に対しては肯定的な意見が多かったが, その場で質問し対応してもらえないことに不満を持つ学生がいることがわかった. すべての課題に学生が主体性をもって参加できるような教材の開発や取り組みを工夫し, さらに学生の質問等に即応できる簡便で使いやすいシステムの構築が必要である. 続きを見る
2.

論文(リポジトリ)

論文(リポジトリ)
Feng, Yejun ; Wang, Yishu ; Silevitch, D. M. ; Yan, J. -Q. ; Kobayashi, Riki ; Hedo, Masato ; Nakama, Takao ; Onuki, Yoshichika ; Suslov, A. V. ; Mihaila, B. ; Littlewood, P. B. ; Rosenbaum, T. F.
出版情報: Proceedings of the National Academy of Sciences of the United States of America.  116  pp.11201-11206,  2019-06-04.  National Academy of Sciences
URL: http://hdl.handle.net/20.500.12000/47031
概要: The magnetoresistance (MR) of a material is typically insensitive to reversing the applied field direction and varies quadratically with magnetic field in the low-field limit. Quantum effects, unusual topological band structures, and inhomogeneities that lead to wandering current paths can induce a cross-over from quadratic to linear MR with increasing magnetic field. Here we explore a series of metallic charge- and spin-density-wave systems that exhibit extremely large positive linear MR. By contrast to other linear MR mechanisms, this effect remains robust down to miniscule magnetic fields of tens of Oersted at low temperature. We frame an explanation of this phenomenon in a semiclassical narrative for a broad category of materials with partially gapped Fermi surfaces due to density waves. 続きを見る
3.

論文(リポジトリ)

論文(リポジトリ)
太田, 譲二 ; 仲村, 大 ; 辺土, 正人 ; 仲間, 隆男 ; Ota, Jouji ; Nakamura, Dai ; Hedo, Masato ; Nakama, Takao
出版情報: 琉球大学理学部紀要 = BULLETIN OF THE FACULTY OF SCIENCE UNIVERSITY OF THE RYUKYUS.  pp.33-41,  2018-09-28.  琉球大学理学部
URL: http://hdl.handle.net/20.500.12000/42785
概要: We have developed a measurement system for the electrical resistivity and thermopower using the programming language of Python on “Raspberry Pi”, a compact computer for education. The measurement equipments are connected to “Raspberry Pi” by the general purpose serial interface bus (USB), which make it possible to operate on PC with the other operating systems of Linux, Windows, and MacOS almost without modification of the measurement program. This ensures the compatibility of measurement system and the unified maintenance and management. 続きを見る
4.

論文(リポジトリ)

論文(リポジトリ)
仲村, 大 ; 辺土, 正人 ; 高江洲, 義尚 ; 内間, 清晴 ; 矢ヶ崎, 克馬 ; 仲間, 隆男 ; 藤原, 哲也 ; 繁岡, 透 ; Nakamura, Dai ; Hedo, Masato ; Takaesu, Yoshinao ; Uchima, Kiyoharu ; Yagasaki, Katsuma ; Nakama, Takao ; Fujiwara, Tetsuya ; Shigeoka, Toru
出版情報: 琉球大学理学部紀要 = Bulletin of the College of Science. University of the Ryukyus.  pp.1-8,  2011-03.  琉球大学理学部
URL: http://hdl.handle.net/20.500.12000/21887
概要: We have developed a set-up with modified "seesaw heating method" for the simultaneous measurement of thermopow er S and electrical resistivity р under hydrostatic pressures P up to 3 GPa at the temperature range between 1.5 K and 300 K. By using this set-up, S and р of single crystalline YbMn_2Ge_2 and EuCo_2P_2 under high pressure were measured with enough accuracy. The temperature dependences of S and р show drastic changes at the critical pressure P_c in both compounds. The measurement results indicate that the simultaneous measurement of S and р is a usuful tool to study the pressure-induced phase transitions. 続きを見る
5.

論文(リポジトリ)

論文(リポジトリ)
高江洲, 義尚 ; 仲間, 隆男 ; 辺土, 正人 ; 内間, 清晴 ; 矢ヶ崎, 克馬 ; A. T. Burkov ; Takaesu, Yoshinao ; Nakama, Takao ; Hedo, Masato ; Uchima, Kiyoharu ; Yagasaki, Katsuma
出版情報: 琉球大学理学部紀要 = Bulletin of the College of Science. University of the Ryukyus.  pp.1-6,  2011-09.  琉球大学理学部
URL: http://hdl.handle.net/20.500.12000/22107
概要: Electrical resistivity p and thermopower S of Y_<1-x>R_xCo_2 (R=Gd, Tb, Dy, Ho and Er) Laves phase systems were measured at temperatures from 1.5 K to 300 K in magnetic fields up to 15 T and under hydrostatic pressures up to 2 GPa. The universal linear relation between the pressure and magnetic field derivatives of the resistivity, dp/dP vs. dp/dB, was observed in the Y_<1-x>R_xCo_2 systems. Similar scaling behavior was found for the thermopower dependence on pressure and magnetic field. 続きを見る
6.

論文(リポジトリ)

論文(リポジトリ)
辺土, 正人 ; Hedo, Masato
出版情報: 2009-06-05.  辺土正人
URL: http://hdl.handle.net/20.500.12000/13468
概要: 2007年度~2008年度科学研究費補助金(若手研究(B))研究成果報告書<br />研究概要:ネオジウム系充填スクッテルダイト様酸化物は原料の反応性がよく、求める結晶構造ができていることを確認した。他にサマリウム系、イットリビ ウム系も同様である。しかし、未反応の原料と思われる不純物が確認され、単相試料が得られていない。セリウム系は何度も合成を試みたが、出発原料から反応が進まず、試料は得られなかった。微少試料での圧力下熱電能測定システムの開発に成功した。それによって、圧力誘起価数転移物質の相転移に伴う大きな電子状態の変化を観測することに成功した。 続きを見る
7.

論文(リポジトリ)

論文(リポジトリ)
仲間, 隆男 ; 辺土, 正人 ; 玉城, 純孝 ; Resel, R. ; Burkov, A.T. ; 矢ヶ崎克馬 ; Nakama, Takao ; Hedo, Masato ; Tamashiro, Junko ; Resel, Roland ; Burkov, Alexander T. ; Yagasaki, Katusma
出版情報: 琉球大学理学部紀要 = Bulletin of the College of Science. University of the Ryukyus.  pp.21-38,  1998-09.  琉球大学理学部
URL: http://hdl.handle.net/20.500.12000/9287
概要: We describe the system for thermopower measurement in magnetic fields up to 17 T in the temperature range from 3 K to 300 K. A special heating technique named "Seesaw heating method", a method similar to ac method, was developed and resulted in good thermal stability and high accuracy. Finding an empirical formula for all the calibration curves of chromel wire utilized as reference material enables us to measure thermopower at any field and at any temperature. The experimental results on GdAl_2 have been successfully analyzed on the basis of Mott's 2-band model with polalized conduction bands using linearized Boltzmann equation. 続きを見る
8.

論文(リポジトリ)

論文(リポジトリ)
仲間, 隆男 ; 大吉, 隆文 ; 辺士, 正人 ; 玉城, 純孝 ; 内間, 清晴 ; Burkov, A.T. ; 矢ヶ崎, 克馬 ; Nakama, Takao ; Oyoshi, Takafumi ; Hedo, Masato ; Tamashiro, Junko ; Uchima, Kiyoharu ; Burkov, Alxander T. ; Yagasaki, Katsuma
出版情報: 琉球大学理学部紀要 = Bulletin of the College of Science. University of the Ryukyus.  pp.11-20,  1998-09.  琉球大学理学部
URL: http://hdl.handle.net/20.500.12000/9288
概要: The experimental set-up for simultaneous measurements of electrical resistivity and thermopower in the temperature range between room temperature and 1300 K was developed. The mechanical contacts of thermocouples, current leads and potential probes with sample were Utilized make it possible to measure a large variety of materials and result in a flexibility with respect to the sample form and dimension. The resistivity and thermopower of pure Ni, CeB_6 heavy fermion compound and a Cr-Si thin film composite are presented as test material to demonstrate the possibilities and accuracy of our experimental set-up. 続きを見る