Browsing by Issue Date, starting with "2018-09-18"

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Elongated Bouncing and Reduced Contact Time of a Drop in the Janus State
(2018-09-18)
Sahoo, Venkataraman
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Chou, Chu-Yao
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Lo, Ching-Wen
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Lu, Ming-Chang
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機械工程學系
Fast drop bouncing is desired in numerous applications. However, it has never been realized on a superheated surface with concurrent contact boiling and the Leidenfrost effect (the so-called Janus thermal state). This is presumably because of the increased drop adhesion as a result of bubbling on a Janus surface. Nevertheless, on a hydrophilic SiNx surface with v-shaped Si microgrooves in this thermal state, an elongated bouncing for a water drop was observed and a small drop contact time of 10.36 ms was obtained. We propose that the elongated bouncing was originated from an asymmetric momentum force created by the vapor bubbles at the rim of the drop. Analytical expressions for the contact time and the asymmetric momentum force were established and the predictions qualitatively agreed with the experimental results. The obtained contact time was the lowest value that has ever been reported in the Janus thermal state. The proposed approach has promising applications in state-of-the-art technologies requiring high liquid mobility.
Deep-Ultraviolet Photodetectors Based on Epitaxial ZnGa(2)O(4 )Thin Films
(2018-09-19)
Tsai, Si-Han
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Basu, Sarbani
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Huang, Chiung-Yi
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Hsu, Liang-Ching
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Lin, Yan-Gu
A single-crystalline( )ZnGn(2)O(4) ( )epilayer was successfully grown on c-plane (0001) sapphire substrate by metal-organic chemical vapor deposition. This epilayer was used as a ternary oxide semiconductor for application in high-performance metal-semiconductor-metal photoconductive deep-ultraviolet (DUV) photodetectors (PDs). At a bias of 5V, the annealed ZnGn(2)O(4) PDs showed better performance with a considerably low dark current of 1 pA, a responsivity of 86.3 A/W, cut-off wavelength of 280 nm, and a high DUV-to-visible discrimination ratio of approximately 10(7) upon exposure to 230 nm DUV illumination than that of as-grown ZnGn(2)O(4 )PDs. The as-grown PDs presented a dark current of 0.5 mA, a responsivity of 2782 A/W at 230 nm, and a photo-to-dark current contrast ratio of approximately one order. The rise time of annealed PDs was 0.5 s, and the relatively quick decay time was 0.7 s. The present results demonstrate that annealing process can reduce the oxygen vacancy defects and be potentially applied in ZnGn(2)O(4) film-based DUV PD devices, which have been rarely reported in previous studies.
交大e-News第263期-電腦嘛A種菜--交通大學無毒智慧科技農業系統合作簽署暨「博士種的」產品義賣
(2018-09-19)
國立交通大學秘書室
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Secretariat
Printable Graphene Oxide Micropatterns for a Bio-Subretinal Chip
(2018-09-19)
Yang, Jia-Wei
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Tseng, Ming-Liang
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Fu, Yu-Min
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Kang, Che-Hao
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Cheng, Yu-Ting
Recently, implantable artificial subretinal chips using electronic components have replaced photoreceptors to serve as the most feasible treatment for retinal diseases. As such a chip that is meant to be implanted and used for very long periods, growing retinal cells on it to improve the electrical stimulation efficiency and attraction of neuronal elements remains a challenge. Here, an inkjet printing technology is employed to create graphene oxide (GO) micropatterns onto microelectrodes of a photovoltaic-powered implantable retinal chip. These GO micropatterns allow human retinal pigment epithelium (RPE) cells to specially attach and grow in each microelectrode. In addition, the cell proliferation, viability, and tight junction of RPE cells are improved during culturing. The development of a simple surface-coating technology would pave the way for the development of the first fully integrated and encapsulated retinal prostheses with biocompatible on-chip microelectrodes for long-term implantation, which could be effectively applied in retina tissue engineering and therapy.
DEHUMIDIFICATION DEVICE WITH ENHANCED DEHUMIDIFICATION EFFECT
(2018-09-20)
CHI-CHUAN WANG
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CHUANG-HUI CHIU
A dehumidification device with enhanced dehumidification effect includes a gas cooler receiving a first air gas and condensing the first air gas into a first condensing gas and a first condensing liquid. A heat exchanger has an inlet and an outlet. The first condensing gas flows from the gas cooler to a periphery of the heat exchanger to cool the heat exchanger. The inlet receives a second air gas from outside. The second air gas is condensed into a second condensing gas and a second condensing liquid using the cooled heat exchanger, and the second condensing gas and the second condensing liquid are expelled from the outlet. A gas heater receives the first condensing gas flowing through the periphery of the heat exchanger and the second condensing gas expelled from the outlet, and heats and turns them into dry air, and the gas heater expels the dry air.
Dynamical instability of the electric transport in superconductors
(2018-09-20)
Qiao, Lei
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Li, Dingping
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Postolova, Svetlana V.
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Mironov, Alexey Yu.
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Vinokur, Valerii
We develop a nonlinear theory of the electronic transport in superconductors in the framework of the time-dependent Ginzburg-Landau (TDGL) equation. We utilize self-consistent Gaussian approximation and reveal the conditions under which the current-voltage V(I) dependence (I-V characteristics) acquires an S-shape form leading to switching instabilities. We demonstrate that in two-dimensions the emergence of such an instability is a hallmark of the Berezinskii-Kosterlitz-Thou less (BKT) transition that we have detected by transport measurements of titanium nitride (TiN) films. Our theoretical findings compare favorably with our experimental results.
CCN6-mediated MMP-9 activation enhances metastatic potential of human chondrosarcoma
(2018-09-20)
Tzeng, Huey-En
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Tang, Chih-Hsin
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Wu, Sz-Hua
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Chen, Hsien-Te
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Fong, Yi-Chin
Chondrosarcomas are primary malignant bone tumors that have a poor prognosis. WNT1-inducible signaling pathway protein-3 (WISP-3, also termed CCN6) belongs to the CCN family of proteins and is implicated in the regulation of various cellular functions, such as cell proliferation, differentiation, and migration. It is unknown as to whether CCN6 affects human chondrosarcoma metastasis. We show how CCN6 promotes chondrosarcoma cell migration and invasion via matrix metallopeptidase-9 (MMP)-9 expression. These effects were abolished by pretreatment of chondrosarcoma cells with PI3K, Akt, mTOR, and NE-KB inhibitors or short interfering (si)RNAs. Our investigations indicate that CCN6 facilitates metastasis through the PI3K/Akt/mTOR/NE-KB signaling pathway. CCN6 and MMP-9 expression was markedly increased in the highly migratory JJ012(S10) cell line compared with the primordial cell line (JJ012) in both in vitro and in vivo experiments. CCN6 knockdown suppressed MMP-9 production in JJ012(S10) cells and attenuated cell migration and invasion ability. Importantly, CCN6 knockdown profoundly inhibited chondrosarcoma cell metastasis to lung. Our findings reveal an important mechanism underlying CCN6-induced metastasis and they highlight the clinical significance between CCN6 and MMP-9 in regard to human chondrosarcoma. CCN6 appears to be a promising therapeutic target in chondrosarcoma metastasis.
Quantum Design for Ultrafast Probing of Molecular Chirality through Enantiomer-Specific Coherent pi-Electron Angular Momentum
(2018-09-20)
Mineo, Hirobumi
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Kim, Gap-Sue
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Lin, Sheng Hsien
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Fujimura, Yuichi
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應用化學系
Probing molecular chirality, right-handed or left-handed chiral molecules, is one of the central issues in chemistry and biochemistry. The conventional theory of optical activity measurements such as circular dichroism has been derived in the second-order processes involving electric and magnetic dipole moments, and the signals are very weak. We propose an efficient enantiomer-probing scenario for chiral aromatic ring molecules based on photoinduced coherent pi-electron rotations. In our model, the resultant laser-induced currents themselves produce a strong magnetic field. The principle for probing molecular chirality is a utilization of dynamic Stark effects of two electronic excited states. These electronic states subjected to strong nonresonant linearly polarized UV lasers become degenerate to create enantiomer-specific electronic angular momentum. A pair of enantiomers of phenylalanine was taken as an example. Enantiomer-specific coherent magnetic fluxes on the order of a few teslas can be generated in several tens of femtoseconds. The direct detection of strong coherent magnetic fluxes could be carried out by time-resolved magnetic force microscopy experiments. The results provide important implications for the measurement of effective probing of chiral aromatic molecules.
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
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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！