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144 results on '"Morimoto, Masato"'

16. Disaggregation of Asphaltene Aggregates in Solutions Depending upon Affinity Indices of the Hansen Solubility Parameter Using Ultrasmall-, Small-, and Wide-Angle X-ray Scattering

Author

Morita, Takeshi, primary, Morimoto, Masato, additional, Shibuta, Satoshi, additional, Imamura, Hiroshi, additional, Yamamoto, Hideki, additional, Tykwinski, Rik R., additional, Scott, David E., additional, Stryker, Jeffrey M., additional, Suzuki, Teruo, additional, and Tanaka, Ryuzo, additional

Published
2022
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26. Optimizing the Iodide/Iodonium/O2 Oxidation Cycle Enhances the Scope, Selectivity, and Yields of Hydroiodic Acid‐Catalyzed Multicomponent Cyclocondensation Reactions.

Author

Scott, David E., Aloisio, Mark D., Rodriguez, Jose F., Morimoto, Masato, Hamilton, Robin J., Brown, Orain, Tykwinski, Rik R., and Stryker, Jeffrey M.

Subjects
OXIDATION, AROMATIC amines, ALIPHATIC compounds, BRONSTED acids, AROMATIZATION, HYDROGEN peroxide, AROMATIC aldehydes
Abstract

Catalytic iodine in the presence of water acts indirectly as a source of Brønsted acid and, concurrently, generates iodonium ion and hydrogen peroxide, which mediate the final oxidative aromatization step in the multicomponent cyclocondensation of an aromatic amine and two aliphatic aldehyde compounds. The oxidative cycle in this and related iodine‐catalyzed reactions is seldom discussed, generally unoptimized, and rarely investigated in detail. This work establishes that two independent catalytic cycles (H+ and I−/I+) drive such multicomponent cyclocondensation/ oxidation reactions, provided that the oxidant is generated in sufficient concentration to inhibit oxidation of the dihydroquinoline by the intermediate iminium cation. The complementary dual catalytic cycles, when optimized, act in concert to suppress side product formation, which simplifies isolation and purification of the self‐aggregating products, and increases the efficiency and scope of the Wang‐Kozlov multicomponent reaction. [ABSTRACT FROM AUTHOR]

Published
2021
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29. Determination of Hansen Solubility Parameters of Asphaltene Model Compounds

Author

Morimoto, Masato, primary, Fukatsu, Naoya, additional, Tanaka, Ryuzo, additional, Takanohashi, Toshimasa, additional, Kumagai, Haruo, additional, Morita, Takeshi, additional, Tykwinski, Rik R., additional, Scott, David E., additional, Stryker, Jeffery M., additional, Gray, Murray R., additional, Sato, Takashi, additional, and Yamamoto, Hideki, additional

Published
2018
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37. Experimental Studies on Nd : YAG Laser Ablation as a Treatment for Tachyarrhythmia

Author

Morimoto, Masato and Okada, Masayoshi

Subjects
Nd : YAG laser, 不整脈の外科治療, Laser ablation, カテーテル焼灼法
Abstract

Laser ablation が, 従来の不整脈治療法を補強する新しい治療手段となり得るか否かを検討した。雑種成犬20頭を用い, 4極カテーテルを右大腿静脈より挿入し, His 束心電図が最大となる部位を検索した。その後右心耳より Laser probe を挿入し, 出力6W～10W, 照射時間3～5秒の Laser ablationを開始した。この方法で完全房室ブロックが作成されるまで Laser 照射を反復した。Argon laser の metal tip probe とNd : YAG laser の ceramic tip probe を用いたが, すべてに完全房室ブロックが作成され, 完全房室ブロック作成に要した平均照射量は Argon laser の224Jに対し, Nd : YAG laser では平均68.2Jと有意に少量のエネルギー量で作成された。組織学的検索では, 焼灼部は完全に coagulation necrosis に陥っていた。Nd : YAG laser の照射出力と変性域の関係を検討したところ, 出力の増加に伴い, 変性域の直径, 深度は増加し, 照射量と最大深度との間には, r=0.935 (P, Recently, a surgival procedure and catheter ablation has been employed for treatment of ventricular tachycardia, that paroxysumal supraventricular tachycardia due to atrio-ventricular nodal reentry is refractory to medical therapy. We have studied for inducing the complete A-V block with application of Argon laser and Nd : YAG laser without extracorporeal circulation. The complete A-V block was produced in all dogs. The histological findings demonstrated that the very narrow segment had been changed to the coagulation necrosis. The border lines between the surrounding tissues were clear, and the ablated lesions were completely fell into the coagulation necrosis with vacuolation. Total laser energy for inducing of the complete A-V block by Nd : YAG laser was in average of 68.2J. And, in case of Argon laser it was 224J in average. We studied the comparison of the qualitative effects of both lasers, size of the circular area of tissue surrounding the crater, that of inducing by Nd : YAG laser was almost 3times as deeper as that of argon laser when the same laser power was discharged to the ventricle. And the width of crater was almost same. We studied the relationship between the deliverd Nd : YAG laser energy and the depth and diameter of the laser induced tissue lesion. There was a closed correlation (r=0.935, p

Published
1999

50. Development of Digital Oil for Heavy Crude Oil: Molecular Model and Molecular Dynamics Simulations

Author

Iwase, Motoaki, Sugiyama, Shumpei, Liang, Yunfeng, Masuda, Yoshihiro, Morimoto, Masato, Matsuoka, Toshifumi, Boek, Edo S., Ueda, Ryo, and Nakagawa, Kazunori

Abstract

We constructed a molecular model (digital oil model) for heavy crude oil based on analytical data. Crude oil was separated into four fractions: saturates, aromatics, resins, and asphaltenes (SARA). The digital oil was constructed as a mixture of representative molecules of saturates, aromatics, resins, and lost components (low boiling-point compounds vaporized during drying), while asphaltenes of ∼0.4 wt % in the crude oil being ignored. Representative molecules were generated by quantitative molecular representation (QMR), a technique that provides a set of molecules consistent with analytical data, such as elemental composition, average molecular mass, and the proportions of structural types of hydrogen and carbon atoms, as revealed by 1H and 13C nuclear magnetic resonance. To enable the QMR method to be applicable to saturates, we made two developments: the first was the generation of nonaromatic molecules by a new algorithm that can generate a more branched structure by separating the chain bonding into main and subsidiary processes; the second was that the molecular mass distribution of the model could be fitted to that obtained from experiments. To validate the digital oil thus obtained, we first confirmed the validity of the model for each fraction in terms of plots of double-bond equivalent as a function of carbon number. We then calculated its density and viscosity by molecular dynamics simulations. The calculated density was in good agreement with experimental data for crude oil. The calculated viscosity was higher than experimental values; however, the error appeared systematic, being a factor of ∼1.5 higher than that of experiments. The calculated viscosity as a function of temperature was well described by the Vogel–Fulcher–Tammann equation. Digital oil will be a powerful tool to analyze both macroscopic properties and microscopic phenomena of crude oil under any thermodynamic conditions.

Published
2018
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