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4. 30S RI Beam Production and X-ray Bursts

Author

Kahl, David, Chen, Alan A., Binh, Dam Nguyen, Chen, Jun, Hashimoto, Takashi, Hayakawa, Seiya, Kim, Aram, Kubono, Shigeru, Kurihara, Yuzo, Lee, Nam Hee, Michimasa, Shin'ichiro, Nishimura, Shunji, Van Ouellet, Christian, nia, Kiana Setoodeh, Wakabayashi, Yasuo, and Yamaguchi, Hideotoshi

Subjects
Nuclear Experiment
Abstract

The present work reports the results of 30S radioactive beam development for a future experiment directly measuring data to extrapolate the 30S(alpha,p) stellar reaction rate in Type I X-ray bursts, a phenomena where nuclear explosions occur repeatedly on the surface of accreting neutron stars. We produce the radioactive ion 30S via the 3He(28Si,30S)n reaction, by bombarding a cryogenically cooled target of 3He at 400 Torr and 80 K with 28Si beams of 6.9 and 7.54 MeV/u. In order to perform a successful future experiment which allows us to calculate the stellar 30S(alpha, p) reaction rate, Hauser-Feshbach calculations indicate we require a 30S beam of ~10^5 particles per second at ~32 MeV. Based on our recent beam development experiments in 2006 and 2008, it is believed that such a beam may be fabricated in 2009 according to the results presented. We plan to measure the 4He(30S,p) cross-section at astrophysical energies in 2009, and some brief remarks on the planned (alpha,p) technique are also elucidated., Comment: 5 pages, 3 figures. Submitted on Dec. 25, 2008 for the Proceedings of the 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA, 27 July - 1 August, 2008. Accepted for publication Jan. 09, 2009

Published
2009

9. Strategic Approach to Diversify Design Options for Li‐Ion Batteries by Utilizing Low‐Ni Layered Cathode Materials (Adv. Energy Mater. 7/2022)

Author

Jeong, Mihee, primary, Lee, Wontae, additional, Yun, Soyeong, additional, Choi, Woosung, additional, Park, Hyunyoung, additional, Lee, Eunkang, additional, Kim, Jaeyoung, additional, Cho, Sung Jun, additional, Lee, Nam‐Hee, additional, Shin, Hyun‐Joon, additional, and Yoon, Won‐Sub, additional

Published
2022
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11. Preparation and Characterization of Silica/Polyamide-imide Nanocomposite Thin Films

Author

Hwang Jong-Sun, Ma Xiaokun, Lee Nam-Hee, Oh Hyo-Jin, and Kim Sun-Jae

Subjects
Composites, Fracture, Surfaces, Thermal properties, Thin films, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Abstract The functional silica/polyamide-imide composite films were prepared via simple ultrasonic blending, after the silica nanoparticles were modified by cationic surfactant—cetyltrimethyl ammonium bromide (CTAB). The composite films were characterized by scanning electron microscope (SEM), thermo gravimetric analysis (TGA) and thermomechanical analysis (TMA). CTAB-modified silica nanoparticles were well dispersed in the polyamide-imide matrix, and the amount of silica nanoparticles to PAI was investigated to be from 2 to 10 wt%. Especially, the coefficients of thermal expansion (CET) continuously decreased with the amount of silica particles increasing. The high thermal stability and low coefficient of thermal expansion showed that the nanocomposite films can be widely used in the enamel wire industry.

Published
2010
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26. Generating test sequences from a set of MSCs

Author

Lee, Nam Hee and Cha, Sung Deok

Subjects
Software development/engineering, Computer networks -- Standards, Computer networks -- Research, Information networks -- Standards, Information networks -- Research, Software engineering -- Standards, Software engineering -- Research
Published
2003

37. Critical conditions at low pressure to improve the quality of directly spinnable CNTs

Author

Lee, Nam Hee and Nahm, Seung-Hoon

Abstract

Continuous fibers produced from carbon nanotube (CNT) rugs through direct spinning find wide applications owing to their excellent mechanical and physical characteristics. However, the practical application of such fibers is difficult since spinnable CNTs synthesized at atmospheric pressure are of low quality. This paper aims to determine the critical conditions for successful CNT rug growth through chemical vapor deposition (CVD) at low pressures such that the resulting CNTs exhibit improved spinnability and uniformity. The parameters examined for this purpose are the heat treatment of the catalyst, growth time, growth pressure, and cooling environment. Such a study has not been reported in literature. Low-pressure (LP) CVD (LP-CVD), which facilitates the control of amorphous carbon to achieve high spinnability, produced directly spinnable CNT rugs up to 600 mm or more. The synthetic method presented in this paper yielded CNTs with spinnability higher than that reported in literature. Thus, the systematic study of the critical conditions required for successful CNT growth through LP-CVD can help obtain CNTs with high spinnability and reproducibility and can improve the commerciality of CNT rugs.

Published
2019
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42. Regulation of the Poly(A) Status of Mitochondrial mRNA by Poly(A)-Specific Ribonuclease Is Conserved among Land Plants.

Author

Kanazawa, Mai, Ikeda, Yoko, Nishihama, Ryuichi, Yamaoka, Shohei, Lee, Nam-Hee, Yamato, Katsuyuki T, Kohchi, Takayuki, and Hirayama, Takashi

Subjects
RIBONUCLEASES, MITOCHONDRIAL RNA, MESSENGER RNA, RECOMBINANT proteins, LIVERWORTS
Abstract

Regulation of the stability and the quality of mitochondrial RNA is essential for the maintenance of mitochondrial and cellular functions in eukaryotes. We have previously reported that the eukaryotic poly(A)-specific ribonuclease (PARN) and the prokaryotic poly(A) polymerase encoded by AHG2 and AGS1 , respectively, coordinately regulate the poly(A) status and the stability of mitochondrial mRNA in Arabidopsis. Mitochondrial function of PARN has not been reported in any other eukaryotes. To know how much this PARN-based mitochondrial mRNA regulation is conserved among plants, we studied the AHG2 and AGS1 counterparts of the liverwort, Marchantia polymorpha , a member of basal land plant lineage. We found that M. polymorpha has one ortholog each for AHG2 and AGS1 , named Mp AHG2 and Mp AGS1 , respectively. Their Citrine-fused proteins were detected in mitochondria of the liverwort. Molecular genetic analysis showed that Mp AHG2 is essential and functionally interacts with Mp AGS1 as observed in Arabidopsis. A recombinant MpAHG2 protein had a deadenylase activity in vitro. Overexpression of Mp AGS1 and the reduced expression of Mp AHG2 caused an accumulation of polyadenylated Mp cox1 mRNA. Furthermore, Mp AHG2 suppressed Arabidopsis ahg2-1 mutant phenotype. These results suggest that the PARN-based mitochondrial mRNA regulatory system is conserved in land plants. [ABSTRACT FROM AUTHOR]

Published
2020
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