Browsing by Issue Date, starting with "2018-09-21"

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Complex strain evolution of polar and magnetic order in multiferroic BiFeO3 thin films
(2018-09-21)
Chen, Zuhuang
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Chen, Zhanghui
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Kuo, Chang-Yang
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Tang, Yunlong
;
Dedon, Liv R.
Electric-field control of magnetism requires deterministic control of the magnetic order and understanding of the magnetoelectric coupling in multiferroics like BiFeO3 and EuTiO3. Despite this critical need, there are few studies on the strain evolution of magnetic order in BiFeO3 films. Here, in (110)-oriented BiFeO3 films, we reveal that while the polarization structure remains relatively unaffected, strain can continuously tune the orientation of the antiferromagnetic-spin axis across a wide angular space, resulting in an unexpected deviation of the classical perpendicular relationship between the antiferromagnetic axis and the polarization. Calculations suggest that this evolution arises from a competition between the Dzyaloshinskii-Moriya interaction and single-ion anisotropy wherein the former dominates at small strains and the two are comparable at large strains. Finally, strong coupling between the BiFeO3 and the ferromagnet Co0.9Fe0.1 exists such that the magnetic anisotropy of the ferromagnet can be effectively controlled by engineering the orientation of the antiferromagnetic-spin axis.
An excited-state Wolff rearrangement reaction of 5-diazo Meldrum's acid: an ab initio on-the-fly nonadiabatic dynamics simulation
(2018-09-21)
Xu, Chao
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Gu, Feng Long
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Zhu, Chaoyuan
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交大名義發表
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應用化學系
A global switching on-the-fly trajectory surface hopping dynamics simulation at the 3SA-CASSCF(12,11)/6-31G* quantum level has been employed to probe the photo-induced Wolff rearrangement (WR) reaction of 5-diazo Meldrum's acid (DMA) within three low-lying electronic excited states. The present simulation predicted that the branching ratios for relaxing back to the ground state, isomerizing to diazirine, and reaction to ketene I via carbene I are 69% +/- 0.1, 3% +/- 0.4, and 28% +/- 0.1, which are in excellent agreement with those obtained by the femtosecond spectroscopy experiment, 67%, 3% and 30%, respectively. In particular, the present simulation revealed that the major WR reaction to ketene I pathway is stepwise via the excited-state to carbene I (17.8% +/- 0.2) and via the ground-state to carbene I (8.7% +/- 0.2), and the minor pathway is concerted synchronous (1.5% +/- 0.6). The photo-induced WR reaction of DMA has been quantitatively interpreted in terms of the distribution of extended seam surfaces as a function of CN dissociation bonds for two important conical intersections within three low-lying electronic excited states. Ultrafast dynamic time constants have been estimated to be about 500 fs +/- 120 fs and 180 fs +/- 80 fs for the stepwise and the concerted WR reaction to ketene I which are also in good agreement with those determined by the experiment. Therefore, the photo-induced excited-state WR reaction mechanism has been quantitatively revealed by the present real-time dynamics simulation.
Synthesis, structures, and reactivity studies of cyclometalated N-heterocyclic carbene complexes of ruthenium
(2018-09-21)
Liu, Hsueh-Ju
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Ziegler, Micah S.
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Tilley, T. Don
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應用化學系
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Department of Applied Chemistry
An unusual cyclometalation reaction results from a C-C bond activation in Cp*(IPr)RuCl to give Cp*(IPr)Ru(L) featuring a NHC-C(sp(2)) chelating ligand (5-L; L = propene, N-2; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; IPr = 1-(6-isopropylphenyl)-3-(2,6-diisopropylphenyl)imidazol-2-ylidene). DFT calculations were employed to elucidate the C-C bond activation pathway. Reactions of cyclometalated ruthenium complexes bearing NHC-C(sp(2)) and NHC-C(sp(3)) ligands (5-L and Cp*(IXy-H)Ru(N-2), 1a, respectively where IXy = 1,3-bis(2,6-dimethylphenyl)-imidazol-2-ylidene; IXy-H is the deprotonated form of (IXy)) are reported. Deprotonation of 1a by an equimolar mixture of benzyl potassium and 18-crown-6 afforded a doubly-cyclometalated complex [Cp*(IXy-2H)Ru][K(18-crown-6)] (7). A lower CO stretching frequency in Cp*(IXy-H)Ru(CO) (8) vs. Cp*(IPr)Ru(CO) (9) suggests that the NHC-C(sp(3)) ligand is more electron donating. Complexes 5-L reacted with H-2 to give the dihydride Cp*(IPr)RuH2 (11). In comparison, after an initial oxidative addition of H-2, complex 1a with its more reactive Ru-C(sp(3)) bond underwent C-H bond reductive elimination, and a second oxidative addition of H-2 afforded the trihydride Cp*(IXy)RuH3 (10). Reaction of 1a with B(C6F5)(3) resulted in a zwitterionic complex Cp*Ru(IXy) (12; IXy = 1-[2-((C6F5)(3)BCH2)C6H3-6-methyl]-3-(2,6-dimethylphenyl)imidazol-2-ylidene-1-yl) by the formation of a new C-B bond. In contrast, B(C6F5)(3) abstracted a hydride from 5-L and promoted a very unusual C-C bond formation involving insertion of an allyl ligand into a Ru-C bond to form [Cp*Ru(IPr)][HB(C6F5)(3)] (IPr = 1-[2-(CH2?CHCH2)C6H3-6-isopropyl]-3-(2,6-diisopropyl)imidazol-2-ylidene-1-yl) (13).
The reaction between the methyl Criegee intermediate and hydrogen chloride: an FTMW spectroscopic study
(2018-09-21)
Cabezas, Carlos
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Endo, Yasuki
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應用化學系
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Department of Applied Chemistry
Experiments using pulsed Fourier-transform microwave spectroscopy have been performed to probe the reaction between the methyl substituted Criegee intermediate, CH3CHOO, and hydrogen chloride. Two conformers of the product derived from the insertion of HCl within CH3CHOO, chloroethyl hydroperoxide, formed in the discharged plasma of a CH3CHI2/O-2/HCl gas mixture, were identified through their experimentally determined rotational and quadrupole coupling constants. The relative abundance of the detected species indicates that the reaction of the anti-CH3CHOO conformer is faster than that of the syn-CH3CHOO conformer. The results presented in this work constitute the first experimental information about the reaction between CH3CHOO and HCl.
大娛樂家　勇敢追夢
(2018-09-23)
林侑萱
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Department of Communication and Technology
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傳播與科技學系
寫2017年音樂電影《大娛樂家》如何用歌曲搭配劇情以及主角巴納姆的心境變化，評論歌曲在電影中的角色
科幻衣多元裏　超感八人組
(2018-09-23)
唐承安
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Department of Communication and Technology
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傳播與科技學系
《超感八人組》於2015年在Netflix平台播出第一季後，頗受好評。時隔三年，於今年2018年播出第二季最後一集，邁入了影集的最終章。
抱團風潮來臨，比賽熱血不再？
(2018-09-23)
黃俊軒
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Department of Communication and Technology
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傳播與科技學系
分析NBA抱團風潮成因和影響
我終究深愛傻子與白痴的世界
(2018-09-23)
何浚捷
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Department of Communication and Technology
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傳播與科技學系
這世界迂迴作弄，讓你失望透頂，卻無可奈何？你是否深愛著這樣的世界？
穿過紛飛的花雨　學習愛自己
(2018-09-23)
許可晴
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Department of Communication and Technology
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傳播與科技學系
人們總是害怕孤獨，嚷嚷「脫單」變成了習慣，於是紛紛戴上面具，想成為某些人眼中最好的自己。BTS《Love Yourself》則提醒我們如何「愛自己」。
致　紅玫瑰與白玫瑰　小老婆
(2018-09-23)
李庭安
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Department of Communication and Technology
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傳播與科技學系
斑斕色彩與情慾交錯，道德感如陰時圓缺。談嘉義的獨立樂團〈美秀集團〉2018帶來的歌曲《小老婆Little Bitch》。
富察皇后的哀傷　知多少
(2018-09-23)
顏筱娟
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Department of Communication and Technology
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傳播與科技學系
富察皇后其實患有複雜性哀傷？現今多數複雜性哀傷患者隱沒在人群，載浮載沉。
答「啡」所問　該喝咖啡嗎？
(2018-09-23)
卓瑋哲
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Department of Communication and Technology
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傳播與科技學系
喝咖啡能為身體帶來益處，也可能造成負擔，該如何拿捏呢？一起來學習聰明喝咖啡吧！
獨立樂團唱出年輕世代的心聲
(2018-09-23)
姚璇
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Department of Communication and Technology
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傳播與科技學系
近十年來，台灣獨立樂團在樂壇蓬勃發展。其中，年輕世代扮演著相當重要的角色。
親子間以愛為名的情緒枷鎖
(2018-09-23)
林奕廷
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Department of Communication and Technology
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傳播與科技學系
情緒勒索存在於親子、伴侶、職場等不同的人際關係，其中親子間的情緒束縛更是時時刻刻壓迫著孩子與父母，本文將著重於親子間情緒勒索的描寫，做深入且詳細的探討，期盼解救陷在這些親密關係中的我們，能解開這名為愛的枷鎖。
我們排隊是為了什麼？
(2018-09-23)
殷顗霖
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Department of Communication and Technology
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傳播與科技學系
不是只有台灣人愛排隊，從心理學的角度來檢視，其實人類就是一種愛排隊的生物。
海洋清潔艦隊　首次出征
(2018-09-23)
陳希妍
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Department of Communication and Technology
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傳播與科技學系
「海洋清潔計畫」由非營利組織The Ocean Cleanup所發起，已籌備多年，且經過無數次的改良，第一部系統001終於在今年9月8日正式啟動。透過該組織獨特的技術及構想，原本需花費千年才能清理完畢的海洋垃圾，將有機會縮短至二十幾年內完成。
打工換宿　翻開人生另一頁
(2018-09-23)
洪蜜禪
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Department of Communication and Technology
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傳播與科技學系
打工換宿的概念從國外的Working holiday發展而來，如今許多台灣青年也藉此方式拓展視野。
德黑蘭禁忌　限制的情與慾
(2018-09-23)
李沛榆
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Department of Communication and Technology
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傳播與科技學系
人類出於原始的本能對於禁忌總是有無盡的遐想。千里之外的德黑蘭，這個對思想嚴格管控的伊斯蘭極權國家，娛樂被視為墮落、女性的自由被限制，人們看似循規蹈矩，但在夜幕低垂下，一顆顆嚮往自由的心悄悄發生著變化。
總編輯的話
(2018-09-23)
許柏悅
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Department of Communication and Technology
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傳播與科技學系
本期為喀報294期，稿數共有26篇，其中以藝文評論及文化現象為主，也有三篇科技新知。
基因研究新突破　向乳癌說拜拜
(2018-09-23)
王允妍
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Department of Communication and Technology
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傳播與科技學系
基因檢測的新研究準確檢驗BRCA1基因突變誘發乳癌的位點，讓乳癌患者能提早確診。