Comparative study of flux pinning, creep and critical currents between YBaCuO crystals with and without Y2BaCuO5 inclusions

In the Y-Ba-Cu-O system, YBa2Cu3O(x) phase is produced by the following peritectic reaction: Y2BaCuO5 + liquid yields 2YBa2Cu3O(x). Through the control of processing conditions and starting compositions, it becomes possible to fabricate large crystals containing fine Y2BaCuO5(211) inclusions. Such crystals exhibit Jc values exceeding 10000 A/sq cm at 77 K and 1T. Recently, researchers developed a novel process which can control the volume fraction of 211 inclusions. Elimination of 211 inclusions is also possible. In this study, researchers prepared YBaCuO crystals with and without 211 inclusions using the novel process, and compared flux pinning, flux creep and critical currents. Magnetic field dependence of Jc for YBaCuO crystals with and with 211 inclusions is shown. It is clear that fine 211 inclusions can contribute to flux pinning. It was also found that flux creep rate could be reduced by increasing flux pinning force. Critical current density estimates based on the conventional flux pinning theory were in good agreement with experimental results

An Analysis of Spoken Discourse of a Movie: Bend It Like Beckham

This paper was written for the fourth year students at Niigata University of International and Information Studies who take the author’s seminar about sociolinguistics to show a model for a B.A. dissertation. This study has analyzed spoken discourse of a movie, Bend It Like Beckham. Two types of conversation were selected in the movie conducted among an Indian family. The talk has been investigated from the different cultural viewpoints suggested by Holliday (1994) and Hall (1977). The conversation has been analyzed with the use of the SPEAKING Model (Hymes, 1974) and two coding systems: IRF (Sinclair & Coulthard, 1975) and Speech Acts (Halliday, 1961). The findings demonstrate that one conversation shows communicative breakdown does not allow IRF to flow smoothly and speakers frequently use Expressive speech acts which can be emotional talk. In contrast, the other conversation shows smooth communication has clear patterns of IRF interaction. Additionally, speakers are aware of social norms in the context and use diplomatic communication skills. This shows they employ a mixture of speech acts which gives impression of logical and objective talk. Finally, it concludes that in order to achieve the purpose of conversation, a high level of communicative competence plays an important role

The Effects of Molecular Crowding on the Structure and Stability of G-Quadruplexes with an Abasic Site

Both cellular environmental factors and chemical modifications critically affect the properties of nucleic acids. However, the structure and stability of DNA containing abasic sites under cell-mimicking molecular crowding conditions remain unclear. Here, we investigated the molecular crowding effects on the structure and stability of the G-quadruplexes including a single abasic site. Structural analysis by circular dichroism showed that molecular crowding by PEG200 did not affect the topology of the G-quadruplex structure with or without an abasic site. Thermodynamic analysis further demonstrated that the degree of stabilization of the G-quadruplex by molecular crowding decreased with substitution of an abasic site for a single guanine. Notably, we found that the molecular crowding effects on the enthalpy change for G-quadruplex formation had a linear relationship with the abasic site effects depending on its position. These results are useful for predicting the structure and stability of G-quadruplexes with abasic sites in the cell-mimicking conditions

Revealing Shifts and Diversity in Understandings of Self Access Language Learning

This study has traced the growth of a new facility intended to promote independent language study in a Japanese university. The study traces this Self Access Learning Center (SALC) from its inception through the first two years of its development. It has revealed how key qualitative insights from an archive of semi-structured interviews, conversational narratives and questionnaires with students, teachers, center staff and university management are marked by their shifting and diverse nature. Findings related to language policy for the center show how initial ‘English only’ regulations have been opposed and amended by stakeholders. Findings focusing on the center stakeholders’ metaphors of self access language learning have changed or been supplemented and show great diversity. Importantly, SALC’s positioning in the wider university has experienced problems with diverse evaluation expectations and, despite considerable financial backing, remains marginalized. Finally, SALC’s integration with university curricula has seen mixed results; the center is connected closely to the English curriculum as taught by non-Japanese, but not to curricula taught by Japanese teachers of English or content subjects. This indicates that integration of university-wide curricula with autonomous modes of learning remains a hurdle. This study may inform other centers seeking to gather data on the diverse voices impacting upon their development

Comparative study of flux pinning flux creep and critical currents between YBaCuO crystals with and without Y2BaCuO5 inclusions

In the Y-Ba-Cu-O system YBa2Cu3Ox phase is produced by the following peritectic reaction: Y2BaCuO5 + liquid yields 2YBa2Cu3Ox. Through the control of processing conditions and starting compositions it becomes possible to fabricate large crystals containing fine Y2BaCuO5(211) inclusions. Such crystals exhibit Jc values exceeding 10000 A/sq cm at 77 K and 1T. Recently, researchers developed a novel process which can control the volume fraction of 211 inclusions. Elimination of 211 inclusions is also possible. In this study, researchers prepared YBaCuO crystals with and without 211 inclusions using the novel process and compared flux pinning, flux creep and critical currents. Magnetic field dependence of Jc for YBaCuO crystals with and without 211 inclusions is shown. It is clear that fine 211 inclusions can contribute to flux pinning. It was also found that flux creep rate could be reduced by increasing flux pinning force. Critical current density estimates based on the conventional flux pinning theory were in good agreement with experimental results

Stress corrosion cracking of copper in swollen bentonite simulating nuclear waste disposal environment

Stress corrosion cracking (SCC) of pure copper in bentonite clay was examined using a slow strain rate test (SSRT). Bentonite was swollen with pure water or aqueous solutions containing NH₃ of 5 and 10 mM. Thick corrosion films and particulate deposits were formed on the copper surface after the SSRT. Typical tarnish rupture-type SCC occurred on pure copper in swollen bentonite with and without NH₃. The crack propagation rate was enhanced by NH₃. It is confirmed that a thick oxide layer was formed on copper during plastic deformation, resulting in tarnish crack-type SCC. Many particulate deposits observed on the surface were formed due to the rapid dissolution of Cu²⁺ ions to form porous CuO at local deformed sites, regardless of the SCC occurrence

ホスホニウムおよびホスフィンオキシド骨格をもつ軸分子の合成とクラウンエーテルによる擬ロタキサンの調製

擬ロタキサンとは、環状分子内を軸分子が貫通した分子であり、軸分子の末端が大きい分子では閉じられていない化合物である。軸分子の両端が閉じているロタキサンと比較して、不安定であることが知られている。ロタキサンは分子機械の重要なパーツであることが知られており、多くの応用研究に利用されているが、高い自由度をもつ擬ロタキサンの応用例はあまり多くない。安定な擬ロタキサンの創製は、新たな機能性材料開発において大きなインパクトを与えることが期待される。本研究では、安定性の高い擬ロタキサンの調製を目指し、軸分子の合成と擬ロタキサンの安定性評価を行った。　擬ロタキサンの安定性向上のために、軸分子と環状分子との間にはたらく相互作用の強化を考えた。環状分子として市販のジベンゾ−24−クラウン−8−エーテル（DB24C8）と24−クラウン−8−エーテル（24C8）を用いるため、軸分子にはクラウンエーテルによって認識されるアンモニウムカチオン部位を導入する。さらにクラウンエーテルとの間に静電相互作用が期待できるホスホニウムカチオン部位を導入する。また芳香環−芳香環相互作用を期待してホスホニウムカチオン上の置換基はフェニル基とした。トリフェニルホスフィンを出発物質として4段階の反応を経て、ホスホニウムカチオン部位とアンモニウムカチオン部位をもつ軸分子を合成した。長さの異なる軸分子とクラウンエーテルから擬ロタキサンを調製し、各種測定により擬ロタキサンの構築が確認された。また会合定数と単結晶X線構造解析の結果より、ホスホニウムカチオン部位の存在および軸分子のフェニル基とDB24C8のベンゼン環とのCH/π相互作用が擬ロタキサンの安定性を向上させうることを明らかにした。　ホスホニウムカチオン部位による擬ロタキサンの安定性向上への寄与はそこまで大きいものではなく、またホスホニウムカチオン部位は比較的安定性が低いため、より安定な構造であるホスフィンオキシド骨格をもつ軸分子の合成を検討した。4−ブロモフェノールを出発物質とし4段階の反応を経て軸分子を合成し、軸分子とDB24C8から擬ロタキサンの形成を行った。会合定数を算出したところ、ホスホニウムカチオン部位をもつときと同程度の安定性で擬ロタキサンが形成されることが明らかとなった。甲南大学令和4年度(2022年度

Magnetic Field-Induced Strain of Metamagnetic Heusler Alloy Ni41Co9Mn31.5Ga18.5

Ni41Co9Mn31.5Ga18.5 is a re-entrant and metamagnetic Heusler alloy. In order to investigate the magnetic functionality of polycrystalline Ni41Co9Mn31.5Ga18.5, magnetic field-induced strain (MFIS) measurements were performed. A 0.12% MFIS was observed at 340 K and 10 T. Strict MFISs between 330 and 370 K were observed. These magneto-structural variances acted in concert with the metamagnetic property observed by the magnetization measurements and magneto-caloric property observed by the caloric measurements in applied magnetic fields. The MFISs were proportional to the fourth power of the magnetization, and this result is in agreement with Takahashi’s spin fluctuation theory of itinerant electron magnetism. The investigation of time response of the MFIS was performed by means of water-cooled electric magnet, zero magnetic field to 1.66 T in 8.0 s at 354 K. A 2.2×10−4 MFIS was observed, which was 80% of the MFIS in a 60-s mode. This indicates that a high-speed transition has occurred on applying magnetic fields

A Case of a Giant Congenital Melanocytic Nevus Treated by Curettage with the Application of Cultured Epidermal Autografts before 6 Months of Age

Curettage is common in the treatment of a giant congenital melanocytic nevus (GCMN) in infants and should generally be performed before 6 months of age. Post-curettage retarded epithelialization often interferes with the ability to perform multiple operations within a short interval, and thus, it is difficult to treat large lesions in the neonatal period. We herein report a case of a GCMN comprising 20% of the total body surface area, which required multi-stage curettage, in which a cultured epithelial autograft was used to promote epithelialization of the post-curettage wound. The patient was a 1-month-old boy with a GCMN in his head, neck, chest, back, buttock, left upper arm, and a few satellite lesions. A four-stage operation was performed between 3 and 6 months of age; the cultured epithelial autograft took well after each operation, and complete epithelialization was observed at postoperative days 20, 23, 27, and 12, respectively. Seven months after the last surgery, hypertrophic scar formation was only observed in a small area of the left upper arm without axillary contracture. The color of the treated area improved, except for slight partial re-pigmentation. A skin biopsy was obtained from the re-pigmented area. The results demonstrated that nevus cells remained in the basal layer of the epidermis, hair follicles, and deep layer of the remaining dermis, suggesting that the recurrent nevus cells in the regenerated epidermis migrated from hair follicles. We conclude that the combination of curettage and the application of a cultured epithelial autograft is a promising option for GCMN treatment