著者

劉 楊

出版者

北海道大学情報法政策学研究センター

雑誌

知的財産法政策学研究 (ISSN:18802982)

巻号頁・発行日

vol.62, pp.309-371, 2022-03

著者

緑川国栄 著

出版者

修教社書院

巻号頁・発行日

1937

著者

池貝 隆宏 三島 聡子 小林 幸文

出版者

日本環境学会

雑誌

人間と環境 (ISSN:0286438X)

巻号頁・発行日

vol.45, no.3, pp.2-14, 2019-10-02 (Released:2020-04-01)

参考文献数

25

被引用文献数

1 1

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神奈川県沿岸のマイクロプラスチック汚染状況を把握するため,相模湾4地点及び東京湾1地点の海岸で漂着マイクロプラスチックの調査を行い,漂着状況の空間変動と時間変動を調べた。空間変動については,満潮線の漂着状況の特徴が海岸間で大きく異なることが分かった。この差は,外洋由来ではなく,内陸の発生源由来のマイクロプラスチックの影響を強く受けたことにより生じたと推定された。満潮線に漂着したマイクロプラスチックの一部は海風により内陸側へ輸送されるが,その傾向はペレットで顕著に表れた。また,満潮線に漂着するマイクロプラスチックのサイズ分布は,沿岸を漂流するマイクロプラスチックに比べて大きいものの割合が高くなることが分かった。時間変動については,気象の影響として沖から陸に向かう風向の強風が長時間続いたときに漂着量が増加し,台風時の漂着量は平時の3倍に達することが分かった。季節変動では,相模湾沿岸では季節風の影響を受け,沖から陸に向かう風が卓越する春期に沖合の漂流マイクロプラスチックが陸域近くに輸送されてその密度が高くなるため,漂着量が増加すると推定された。一方,マイクロプラスチックの材質構成は,期間を通じて大きな変化は見られなかった。2つの海岸で漂着が確認された小粒径の発泡ポリスチレン球の由来を推定したところ,クッション材として利用される微小発泡ビーズの可能性が高いと推定された。こうした製品の適正な処理が重要であることが示唆された。

著者

小林 俊介 片岡 智哉 宮本 颯太 二瓶 泰雄

出版者

公益社団法人 土木学会

雑誌

土木学会論文集B1(水工学) (ISSN:2185467X)

巻号頁・発行日

vol.75, no.2, pp.I_439-I_444, 2019 (Released:2020-11-16)

参考文献数

18

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本研究では,河川水中の5mm以下の微細なプラスチック片(microplastics,MP)の輸送特性を明らかにするために,平常時に江戸川野田橋で現地観測を行い,MP濃度鉛直分布を調べるとともに,採取されたMPを用いた室内実験を行うことでMPの上昇(沈降)速度を調べた.河川におけるMP濃度の鉛直分布には,水表面と底面付近にピークがあり,水表面(底面)には比重が1以下(1以上)のMPが比較的多く分布していた.また,MPの沈降速度(平均: 13.5 mm/s)は,上昇速度(平均: 2.68mm/s)よりも大きく,サイズと共に増加していた.従って,河川水中の鉛直混合下であっても,比重の大きなMPが底層に沈降していることが示唆された.

著者

河村 亜希 杉田 正明

出版者

Japan Society of Nutrition and Food Science

雑誌

日本栄養・食糧学会誌 (ISSN:02873516)

巻号頁・発行日

vol.73, no.5, pp.199-205, 2020 (Released:2020-10-19)

参考文献数

32

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スポーツ現場におけるn-3系脂肪酸摂取の有用性が示唆されているが, スポーツ選手を対象とした先行報告は極めて少ない。本研究は, n-3系脂肪酸であるエイコサペンタエン酸 (EPA) およびドコサヘキサエン酸 (DHA) の24か月間の摂取が女子長距離選手における血中脂肪酸濃度の変化に及ぼす影響を知ることを目的とした。12名の選手に対してEPA 664 mg, DHA 284 mgを24か月間毎日摂取させ, 1か月に1回の血液検査を実施した。その結果, 血中EPA濃度は介入前と比較し3か月後に126% (p<0.01) 増加し, 血中アラキドン酸 (AA) 濃度は1か月後に17% (p<0.05) 減少した。EPA/AA比は介入前 (0.41±0.04) と比較し3か月後 (0.86±0.05) に110% (p<0.01) 増加し, その後0.67‐0.98の範囲で推移した (p<0.05, p<0.01) 。一方, DHAの血中濃度に変化は見られなかった。従って, 女子長距離選手におけるEPAおよびDHAの日常的な摂取は, 血中EPA濃度を増加させ, 血中AA濃度を低下させることで長期的にEPA/AA比を高めることが確認された。

著者

川端康成著

出版者

東和社

巻号頁・発行日

1948

著者

黒川真頼, 横山由清 編

出版者

旧典類纂会

巻号頁・発行日

vol.下, 1939

出版者

磯部甲陽堂

巻号頁・発行日

1913

著者

兒玉 学 平井 秀一郎

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.142, no.3, pp.199-204, 2022-03-01 (Released:2022-03-01)

参考文献数

12

被引用文献数

2

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Applying a magnetic field to a water electrolyzer is one of the methods to improve energy conversion efficiency from electrical energy to hydrogen energy. In this study, experiments of alkaline water electrolysis with a magnetic field are carried out to elucidate the influence of a magnetic field direction and a magnetic flux density on cell voltage and bubble movement. In the case with B⊥electrode, the cell voltage decreases with the increase in current density and magnetic flux density, because the bubbles are removed from the electrode and the electrolyte is mixed with Lorentz-force. In the case with B∥electrode, the cell voltage is suppressed in low current density conditions. However, in high current density conditions, the bubbles are trapped in the electrolyte and the cell voltage is increased.

著者

Meng GUO Hiromasa MORIYAMA Yoshihiro HARADA Hideaki NISHIMURA Manabu KODAMA Shuichiro HIRAI Masami KADONAGA Koichi KATO Kazuyoshi FUSHINOBU

出版者

The Imaging Society of Japan

雑誌

日本画像学会誌 (ISSN:13444425)

巻号頁・発行日

vol.60, no.6, pp.580-591, 2021-12-10 (Released:2021-12-11)

参考文献数

20

被引用文献数

1

---

Theoretical models to integrate pores size distribution and to analyze permeation of a droplet into coated paper are proposed. Droplet permeation into porous media plays an important role in the image formation of inkjet printing. In this study, pores size distribution of porous media of different coated papers was investigated using nitrogen adsorption-desorption method. Based on the pores size distribution, theoretical model for estimating permeation amount into coated paper of pico-scale droplet was proposed, with the consideration of Lucas-Washburn equation. In order to verify the theoretical model, experiments of droplet observation with pure water and several propylene glycol (PG) aqueous solutions were conducted. For some paper samples, results of theoretical calculation and experiments generally agree well. However, there are cases where the theoretical predictions show discrepancy. Possible reasons are considered to be deviation of pores size distribution. Moreover, the accuracy of estimated evaporation volume by Hu and Larson's Equation, and the complex shape of the pores in coated layer also contribute to the errors. The effect of these factors still needs to be further explored.

著者

兒玉 学 戸瀬 義久 奥村 一彦 平井 秀一郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.86, no.892, pp.20-00183, 2020 (Released:2020-12-25)

参考文献数

16

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Electrolyzed water generator can produce acidic and alkaline water from tap water and electric power, and is expected to have applications in the food and medical fields for sterilization, cleaning and disinfection. However, there are still many unknowns about the internal phenomena of the electrolytic water production system, especially the two-dimensional phenomena that have a strong influence on the miniaturization, power saving, and longevity of the electrolyzed water generator. In this study, multi physics modeling of electrolyzed water generator and two-dimensional numerical simulations are conducted to elucidate the fluid, electrochemical, and electrical phenomena in an electrolyzed water generator. The numerical model is built with governing equations from fluid dynamics, electrochemistry, and electrodynamics. The results show that the neutralization reaction with hydrogen carbonate (HCO3-) is an important reaction in electrolyzed water generator, and this reaction divides the anode cell into two regions (low pH region and high pH region), and the electrical conductivity is low in the low pH region. This region with low pH and electrical conductivity extends to the mainstream direction. The current density on the upstream of anode is higher than that of the downstream of anode. This occurs since the region with low electrical conductivity becomes increasingly thicker moving downstream.

著者

兒玉 学 木内 豪士 鳥居 健次郎 平井 秀一郎

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.140, no.7, pp.617-622, 2020-07-01 (Released:2020-07-01)

参考文献数

16

被引用文献数

3 5

---

Three dimensional magnetohydrodynamic, two-phase flow and electrochemical reaction coupling numerical simulation of alkaline water electrolysis with magnetic field is conducted to estimate and reveal the mechanism of overvoltage suppression with the magnetic field. The numerical results shown that both vertical magnetic field to the electrode and parallel magnetic field to the electrode suppress the overpotential by the mixing of the electrolyte. This mixing is induced by the secondary flow in both cases. The overvoltage suppression is constantly increased with the increase in magnetic flux density in the case with parallel magnetic field, however, that is saturates in the case with vertical magnetic field to the electrode due to the bubble position is changed by the flow.

著者

兒玉 学 鳥居 健次郎 平井 秀一郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.86, no.883, pp.19-00354, 2020 (Released:2020-03-25)

参考文献数

17

被引用文献数

2 1

---

In this paper, two-phase flow and ion transportation in an alkaline water electrolysis are discussed with three-dimensional coupling numerical simulation to reveal the influence of a bubble in the alkaline water electrolysis on the cell efficiency to achieve high-efficiency energy conversion of electrical energy to hydrogen energy. Two-phase flow numerical simulation model is not a void ratio model that is mainly used in previous studies, but is a direct simulation model with Lattices Kinetic Scheme that enables microscale flow simulation. Moreover, the concentration distribution is calculated with Maxwell equation and Nernst-Planks equation, and is fully coupled to the three-dimensional two-phase flow. The numerical simulations are conducted for w/o bubble condition and w/ bubble condition with varying applied current density to evaluate the influence of a bubble at various operating conditions. The results show that the bubble in the electrolyte induces mixing flow between a bubble and an electrode, and the concentration of potassium hydroxide (KOH) around the anode is increased. This increase of concentration increases the conductivity of the electrolyte and suppresses the overpotential in the electrolyte. Moreover, the anodic activation overpotential is also suppressed by the increased concentration on the anode. These overvoltage suppressions become much more prominent at high current density operating condition of the cell. The mixing with the bubble changes the concentration around the bubble. However, concentration distant from the bubble also changes and suppresses the overpotential with the change in electrical field.

著者

鶴岡 美緒 田中 学 奥野 喜裕

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.138, no.3, pp.236-241, 2018-03-01 (Released:2018-03-01)

参考文献数

28

被引用文献数

1 1

---

Power generating characteristics of seed-free linear shaped Faraday type and disk shaped Hall type MHD generators are examined by two-dimensional numerical simulation with changing the inlet ionization degree. A liner shaped Faraday type generator can get stable and high power output at high inlet ionization degree. The net enthalpy extraction ratio, however, is reduced owing to the increase in the required preionization power. At low inlet ionization degree, on the other hand, ionization instability occurs and the enthalpy extraction ratio decreases. A disk shaped Hall type generator can get high net enthalpy extraction ratio even at low inlet ionization degree under a low preionization power. The net enthalpy extraction ratio decreases for an excessive inlet ionization degree because of a strong MHD interaction.

著者

卓 新民 田中 学 奥野 喜裕

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.136, no.10, pp.779-784, 2016-10-01 (Released:2016-10-01)

参考文献数

17

被引用文献数

2 2

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The performance and plasma stability in a high-temperature inert gas plasma MHD generator with a high enthalpy extraction ratio have been simulated numerically. To achieve a high enthalpy extraction ratio, various generator channel lengths and magnetic flux density distributions are examined so as to improve the MHD interaction strength and effective electrical conductivity. It is found that an enthalpy extraction ratio of 30% is reachable for high-temperature inert gas plasma MHD generator, and as being similar to an experimental small-scale generator, steady and homogeneous plasma can be realized at a high inlet total temperature even for a high enthalpy extraction generator with long channel length and shaped magnetic flux density distribution.

著者

田中 学 泉 裕一朗 奥野 喜裕

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.136, no.2, pp.205-210, 2016-02-01 (Released:2016-02-01)

参考文献数

22

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MHD (magnetohydrodynamic) electrical power generation experiments have been conducted with a seed-free high temperature inert gas plasma in a disk-shaped Hall-type generator driven by a single-pulsed shock tunnel. Xenon is used as a working gas to archive a high performance at a low inlet total temperature, where the total gas temperature is varied in the range of 4600-10000K at the generator inlet. An enthalpy extraction ratio of 4.8% is obtained at the inlet total temperature of 7000K, and this value is much higher than that for argon at the same inlet total temperature. The unstable and non-uniform plasma attributed to ionization instability is observed at a high magnetic flux density and a high load resistance.

著者

田中 学 奥野 喜裕

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.135, no.8, pp.527-532, 2015-08-01 (Released:2015-08-01)

参考文献数

22

被引用文献数

5 3

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R-θ two dimensional numerical simulations have been carried out to clarify the plasma behavior in a high-temperature inert gas plasma disk-shaped MHD generator. At low inlet total temperature and high load resistance, the plasma has spiral structure which is similar to the non-uniform structure under the weak noble gas ionization condition in a seed-plasma MHD generator. As seen in a linear-shaped faraday-type MHD generator, the plasma becomes stable with increase in the inlet total temperature because the coulomb collision of electrons becomes dominant. Even at low inlet total temperature, the ionization instability can be suppressed for low load resistance, because the relatively low electron temperature due to less Joule heating makes the ionization relaxation time longer than plasma residential time.

著者

小松 文彦 田中 学 村上 朝之 奥野 喜裕

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.134, no.7, pp.620-625, 2014 (Released:2014-07-01)

参考文献数

9

被引用文献数

5 5

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High temperature inert gas (argon) plasma MHD electrical power generation using a linear shaped channel with Hall and diagonal connections has been conducted. It is revealed from the observation by using a high-speed camera that the MHD power-generating plasma is almost stable regardless of the connection type. Enthalpy extraction ratios of 5.6% for the Hall connection, 6.7% for the diagonal connection (diagonal angle 53∼66 degree), and 10.1% for the diagonal connection (diagonal angle 36∼48 degree) have been achieved under the operating conditions of an inlet total temperature of 9000K, an inlet total pressure of 0.105MPa, and a magnetic flux density of 4.0T. The output power can suffer from a low electric field in the upstream region in a Hall connection, and is improved for no Hall current condition in a diagonal connection.

著者

田中 学 村上 朝之 奥野 喜裕

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.134, no.7, pp.614-619, 2014 (Released:2014-07-01)

参考文献数

13

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MHD power generation experiments have been conducted by using a single-pulsed shock-tunnel facility, where the high temperature inert gas (pure argon) at a fixed total temperature of 9000K is introduced into a linear shaped Faraday type generator without any seeding. The fluctuations in the output power and the light emission from the plasma are found to be small, and the pure inert gas plasma seems to be rather stable free from the ionization instability. The output power is improved with increasing the magnetic flux density in almost quadric way and the enthalpy extraction ratio does not depend on the inlet total pressure (11.2%-12.9% for 0.063MPa-0.105MPa). The generator performance obtained here is surely competitive or superior to that of conventional seed plasma MHD generators in the past.

著者

田中 学 村上 朝之 奥野 喜裕

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.134, no.5, pp.464-469, 2014 (Released:2014-05-01)

参考文献数

16

被引用文献数

3 3

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The plasma fluid flow behavior and power generation characteristics in a Faraday-type magnetohydrodynamics (MHD) generator using high temperature inert gas (argon) plasma has been examined by a time-dependent two-dimensional numerical simulation. The inhomogeneous and unstable plasma at an inlet total temperature of 7000K results in the reduction and fluctuation of the output power. The plasma changes to homogeneous and stable one with the increase in the inlet total temperature to 9000K. One of the reasons of the suppression of the ionization instability can be due to the weakness of the dependency of the electrical conductivity on the electron number density because the coulomb collision of electrons becomes dominant under the departure from Saha equilibrium.