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Takei, Satoshi*; Oshima, Akihiro*; Oyama, Tomoko; Ito, Kenta*; Sugahara, Kigen*; Kashiwakura, Miki*; Kozawa, Takahiro*; Tagawa, Seiichi*; Hanabata, Makoto*
Japanese Journal of Applied Physics, 53(11), p.116505_1 - 116505_7, 2014/11
Times Cited Count：10 Percentile：41.38(Physics, Applied)The application of natural linear polysaccharide to green resists was demonstrated for electron beam (EB) and extreme-ultraviolet (EUV) lithography. Because of the water solubility of natural polysaccharides, the water spin-coating and water-developable processes realize an environmentally friendly manufacturing process for next-generation electronic devices. The developed green resist with a weight-average molecular weight of 83,000 and 70 mol % hydroxyl groups was found to have acceptable properties such as spin-coat ability on 200 mm wafers, pillar patterns of 100-400 nm with a high EB sensitivity of 10 
C/cm
, etch selectivity with a silicon-based middle layer in CF
plasma treatment, and high prediction sensitivity to EUV region.
Ohno, Shuji; Oki, Hiroshi*; Sugahara, Akihiro*; Ohshima, Hiroyuki
Journal of Nuclear Science and Technology, 48(2), p.205 - 214, 2011/02
Times Cited Count：11 Percentile：64.09(Nuclear Science & Technology)Validation of a numerical simulation method is carried out for thermal stratification phenomena in the reactor vessel upper plenum of advanced sodium-cooled fast reactors. The study mainly focuses on the fundamental applicability of commercial computational fluid dynamics (CFD) codes as well as an in-house code to the evaluation of thermal stratification behavior including the simulation methods such as spatial mesh distribution and RANS-type turbulence models in the analyses.
Ohno, Shuji; Sugahara, Akihiro*; Oki, Hiroshi*; Ohshima, Hiroyuki
Proceedings of 7th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-7) (CD-ROM), 6 Pages, 2010/11
Parametric analyses were carried out as numerical experiments to clarify the basic characteristics of thermal stratification behavior in upper plenum of fast reactors. The analyses were performed changing hypothetically the analytical conditions of sodium flow rate, sodium temperature, and the size of analyzed upper plenum, by using a commercial CFD code FLUENT Ver. 6.3 and the RNG k-
turbulence model. The results provided the suggestion that the averaged sodium ascending velocity in the reactor upper plenum region and the sodium temperature difference before and after the transient initiation would be the dominant factors to determine temperature gradient of thermal stratification interface. Further, it was implied that appropriate spatial mesh arrangement in vertical direction around the stratification interface is significant to obtain the accurate numerical solution of interface temperature gradient.
Ohno, Shuji; Sugahara, Akihiro*; Oki, Hiroshi*; Ohshima, Hiroyuki
Nihon Kikai Gakkai Rombunshu, B, 76(763), p.451 - 453, 2010/03
Three-dimensional thermal-hydraulic analyses have been carried out for a sodium experiment in a relatively simple axis-symmetric geometry using a commercial CFD code in order to validate simulating methods for thermal stratification behavior in an upper plenum of sodium-cooled fast reactor. Detailed comparison between simulated results and experimental measurement has demonstrated that the code reproduced fairly well the fundamental thermal stratification behaviors such as vertical temperature gradient and upward movement of a stratification interface when utilizing high-order discretization scheme and appropriate mesh size. Furthermore, the investigation has clarified the influence of RANS type turbulence models on phenomena predictability; i.e. the standard 
- model, the RNG - model and the Reynolds Stress Model.
Ohno, Shuji; Ohshima, Hiroyuki; Sugahara, Akihiro*; Oki, Hiroshi*
Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 12 Pages, 2009/09
Multi-dimensional transient thermal hydraulic analyses for a sodium experiment are carried out in order to validate the applicability of basic simulation methods to a typical thermal stratification behavior in a reactor upper plenum region. Simulation predictability of the behavior is evaluated after the results of an existing experiment are reviewed and important fundamental characteristics of the behavior are quantified. The investigated results clarify that CFD codes provide good prediction for fundamental phenomena of steep temperature gradient and gradual rising behavior of the stratification interface under the condition of adopting appropriate mesh size, higher-order discretization scheme, and the RANS turbulence model.
Ohno, Shuji; Oki, Hiroshi*; Sugahara, Akihiro*; Ohshima, Hiroyuki
Nihon Kikai Gakkai Rombunshu, B, 75(751), p.464 - 465, 2009/03
Three-dimensional thermal-hydraulic analyses of thermal stratification phenomena have been carried out in order to validate simulating ability of a single-phase thermal hydraulic code AQUA and commercial CFD codes STAR-CD and FLUENT. The analyses of thermal stratification water experiments demonstrated that the codes reproduced temperature gradient and upward movement of the stratification interface in the case of utilizing appropriate discretization method and computational mesh arrangement for gravitational direction. No remarkable difference was observed between the calculated results with three codes. It was also shown that three turbulence models of the standard k-e model, the RNG k-e model and the RSM predicted fairly well the fundamental stratification behavior observed in the experiments.
Ohno, Shuji; Oki, Hiroshi*; Sugahara, Akihiro*; Ohshima, Hiroyuki
Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 7 Pages, 2008/11
Validation study of numerical simulation method is in progress for thermal stratification phenomena in a reactor vessel upper plenum of advanced sodium-cooled fast reactors. This paper describes the current status of the study using two kinds of thermal stratification experiments and commercial CFD codes STAR-CD, FLUENT, and an in-house code AQUA.
Ohno, Shuji; Oki, Hiroshi*; Sugahara, Akihiro*; Ohshima, Hiroyuki
no journal, ,
Three-dimensional thermal-hydraulic analyses of thermal stratification phenomena have been carried out in order to validate simulating ability of single-phase thermal hydraulic code AQUA and commercial CFD codes STAR-CD and FLUENT. The analyses of thermal stratification water experiments demonstrated that the codes reproduced temperature gradient and upward movement of the stratification interface in the case of utilizing appropriate discretization method and computational mesh arrangement for gravitational direction. No remarkable difference was observed between the calculated results with three codes. It was also shown that three turbulence models of standard k-, RNG k- and RSM indicated little difference in the predicted results of basic stratification phenomena observed in the experiments.
Ohno, Shuji; Ohshima, Hiroyuki; Sugahara, Akihiro*; Oki, Hiroshi*
no journal, ,
Validation study on numerical simulation method has been in progress for evaluating thermal-hydraulic behavior in an upper plenum region of advanced sodium-cooled fast reactors. The present study investigates the applicability of the RANS-type turbulence models to the evaluation of fundamental thermal stratification behavior using a commercial CFD code and the existing sodium experiment data.
Ohno, Shuji; Sugahara, Akihiro*; Oki, Hiroshi*; Ohshima, Hiroyuki
no journal, ,
Three-dimensional analyses of a sodium experiment in a relatively simple geometry have been carried out using a commercial CFD code in order to validate simulating methods of thermal stratification behavior in an upper plenum of sodium-cooled fast reactor. Comparison between analyses and experimental measurement has demonstrated that the code reproduced fairly well the fundamental thermal stratification behaviors such as temperature gradient and upward movement of a stratification interface with utilizing the RANS turbulence model. Furthermore, the investigation has clarified the influence of models on phenomena predictability, for three turbulence models of standard k-, RNG k- and Reynolds Stress Model.
Ohno, Shuji; Ohshima, Hiroyuki; Sugahara, Akihiro*; Oki, Hiroshi*
no journal, ,
Numerical analyses of thermal stratification experiments in relatively simple geometries have been carried out in order to validate simulating methods of the behavior in an upper plenum of sodium-cooled fast reactor. This time, fundamental numerical simulation methods to be adopted are investigated through sensitivity analyses and numerical experiments using a CFD code.
