Browsing by Issue Date, starting with "2020-06-02"

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Demonstration of 1-Gbps real-time optical wireless communication by simple transmission scheme
(2020-06-02)
Yeh, Chien-Hung
;
Luo, Chien-Ming
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Xie, Yue-Ru
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Chow, Chi-Wai
;
Chen, Ruei-Bin
In the work, we propose and investigate a real-time optical wireless communication (OWC) system with 1 Gbps on-off keying (OOK) traffic rate for indoor and outdoor transmissions. Here, 1 Gbps OWC traffic with error-free operation can be achieved indoors under the free space transmission length of 500 m based on the simulation and experimental results. In addition, 952, 904, 476 Mbps throughput rates of proposed real-time OWC system are measured outdoors after passing through the wireless transmission lengths of 120, 300 and 500 m, respectively.
Zika Virus NS3 Protease Pharmacophore Anchor Model and Drug Discovery
(2020-06-02)
Pathak, Nikhil
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Kuo, Yi-Ping
;
Chang, Teng-Yuan
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Huang, Chin-Ting
;
Hung, Hui-Chen
Zika virus (ZIKV) of the flaviviridae family, is the cause of emerging infections characterized by fever, Guillain-Barre syndrome (GBS) in adults and microcephaly in newborns. There exists an urgent unmet clinical need for anti-ZIKV drugs for the treatment of infected individuals. In the current work, we aimed at the promising virus drug target, ZIKV NS3 protease and constructed a Pharmacophore Anchor (PA) model for the active site. The PA model reveals a total of 12 anchors (E, H, V) mapped across the active site subpockets. We further identified five of these anchors to be critical core anchors (CEH1, CH3, CH7, CV1, CV3) conserved across flaviviral proteases. The ZIKV protease PA model was then applied in anchor-enhanced virtual screening yielding 14 potential antiviral candidates, which were tested by in vitro assays. We discovered FDA drugs Asunaprevir and Simeprevir to have potent anti-ZIKV activities with EC50 values 4.7 mu M and 0.4 mu M, inhibiting the viral protease with IC50 values 6.0 mu M and 2.6 mu M respectively. Additionally, the PA model anchors aided in the exploration of inhibitor binding mechanisms. In conclusion, our PA model serves as a promising guide map for ZIKV protease targeted drug discovery and the identified 'previr' FDA drugs are promising for anti-ZIKV treatments.
Relationship between Energy Dosage and Apoptotic Cell Death by Modulated Electro-Hyperthermia
(2020-06-02)
Kao, Patrick Hung-Ju
;
Chen, Chia-Hung
;
Tsang, Yuk-Wah
;
Lin, Chen-Si
;
Chiang, Hsin-Chien
Modulated electro-hyperthermia (mEHT) is a form of mild hyperthermia (HT) used for cancer treatment. The principle utility of HT is the ability not only to increase cell temperature, but also to increase blood flow and associated pO(2) to the microenvironment. While investigational evidence has shown the unique ability of mEHT to elicit apoptosis in cancer cells, in vivo and in vitro, the same trait has not been observed with conventional HT. There is dissension as to what allows mEHT to elicit apoptosis despite heating to only mild temperatures, with the predominant opinion in favor of increased temperature at a cellular level as the driving force. For this study, we hypothesized that in addition to temperature, the amount of electrical energy delivered is a major factor in induction of apoptosis by mEHT. To evaluate the impact of electrical energy on apoptosis, we divided generally practiced mEHT treatment into 3 phases: Phase I (treatment start to 10min. mark): escalation from 25 degrees C to 37 degrees C Phase II (10min. mark to 15min. mark): escalation from 37 degrees C to 42 degrees C Phase III (15min. mark to 45min. mark): maintenance at 42 degrees C Combinations of mEHT at 18W power, mEHT at 7.5W power, water bath, and incubator were applied to each of the three phases. Power output was recorded per second and calculated as average power per second. Total number of corresponding Joules emitted per each experiment was also recorded. The biological effect of apoptotic cell death was assayed by annexin-V assay. In group where mEHT was applied for all three phases, apoptosis rate was measured at 31.18 +/- 1.47%. In group where mEHT was only applied in Phases II and III, apoptosis rate dropped to 20.2 +/- 2.1%. Where mEHT was only applied in Phase III, apoptosis was 6.4 +/- 1.7%. Interestingly, when mEHT was applied in Phases I and II, whether Phase III was conducted in either water bath at 42 degrees C or incubator at 37 degrees C, resulted in nearly identical apoptosis rates, 26 +/- 4.4% and 25.9 +/- 3.1%, respectively. These results showed that accumulation of mEHT at high-powered setting (18W/sec) during temperature escalation (Phase I and Phase II), significantly increased apoptosis of tested cancer cells. The data also showed that whereas apoptosis rate was significantly increased during temperature escalation by higher power (18W/sec), apoptosis was limited during temperature maintenance with lower power (7.5W/sec). This presents that neither maintenance of 42 degrees C nor accumulation of Joules by mEHT has immediate correlating effect on apoptosis rate. These findings may offer a basis for direction of clinical application of mEHT treatment.
Solution-Processable Quinoidal Dithioalkylterthiophene-Based Small Molecules Pseudo-Pentathienoacenes via an Intramolecular S center dot center dot center dot S Lock for High-Performance n-Type Organic Field-Effect Transistors
(2020-06-03)
Vegiraju, Sureshraju
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Torimtubun, Alfonsina Abat Amelenan
;
Lin, Po-Shen
;
Tsai, Hsin-Chia
;
Lien, Wei-Chieh
A new organic small-molecule family comprising tetracyanoquinodimethane-substituted quinoidal dithioalky(SR)terthiophenes (DSTQs) (DSTQ-6 (1); SR = SC6H13, DSTQ : 10 (2); SR = SC10H21, DSTQ14 (3); SR = SC10H21) was synthesized and contrasted with a nonthioalkylated analogue (DRTQ14 (4); R = C14H29). The physical, electrochemical, and electrical properties of these new compounds are thoroughly investigated. Optimized geometries obtained from density functional theory calculations and single-crystal X-ray diffraction reveal the planarity of the SR-containing DSTQ core. DSTQs pack in a slipped pi-pi stacked two-dimensional arrangement, with a short intermolecular stacking distance of 3.55 A and short intermolecular S center dot center dot center dot N contacts of 3.56 angstrom. Thin-film morphological analysis by grazing incident X-ray diffraction reveals that all DSTQ molecules are packed in an edge-on fashion on the substrate. The favorable molecular packing, the high core planarity, and very low lowest unoccupied molecular orbital (LUMO) energy level (-4.2 eV) suggest that DSTQs could be electron-transporting semiconductors. Organic field-effect transistors based on solution-sheared DSTQ : 14 exhibit the highest electron mobility of 0.77 cm(2) V-1 s(-1) with good ambient stability, which is the highest value reported to date for such a solution process terthiophene-based small molecular semiconductor. These results demonstrate that the device performance of solution-sheared DSTQs can be improved by side chain engineering.
Near-Infrared Laser-Annealed IZO Flexible Device as a Sensitive H2S Sensor at Room Temperature
(2020-06-03)
Chang, Po-Yi
;
Lin, Ching-Fu
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Rouphael, Samer El Khoury
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Huang, Ting-Hsuan
;
Wu, Chang-Mao
A metal-oxide material (indium zinc oxide [IZO]) device with near-infrared (NIR) laser annealing was demonstrated on both glass and bendable plastic substrates (polycarbonate, polyethylene, and polyethylene terephthalate). After only 60 s, the sheet resistance of IZO films annealed with a laser was comparable to that of thermal-annealed devices at temperatures in the range of 200-300 degrees C (1 h). XPS, ATR, and AFM were used to investigate the changes in the sheet resistance and correlate them to the composition and morphology of the thin film. Finally, the NIR-laser-annealed IZO films were demonstrated to be capable of detecting changes in humidity and serving as a highly sensitive gas sensor of hydrogen sulfide (in ppb concentration), with room-temperature operation on a bendable substrate.
Scanning tunneling spectroscopy studies of topological materials
(2020-06-03)
Lin, Chun-Liang
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Kawakami, Naoya
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Arafune, Ryuichi
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Minamitani, Emi
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Takagi, Noriaki
Topological materials have become promising materials for next-generation devices by utilizing their exotic electronic states. Their exotic states caused by spin-orbital coupling usually locate on the surfaces or at the edges. Scanning tunneling spectroscopy (STS) is a powerful tool to reveal the local electronic structures of condensed matters. Therefore, STS provides us with an almost perfect method to access the exotic states of topological materials. In this topical review, we report the current investigations by several methods based on the STS technique for layered topological material from transition metal dichalcogenide Weyl semimetals (WTe2 and MoTe2) to two dimensional topological insulators (layered bismuth and silicene). The electronic characteristics of these layered topological materials are experimentally identified.
Effect of Reverse Currents during Electroplating on the < 111 >-Oriented and Nanotwinned Columnar Grain Growth of Copper Films
(2020-06-03)
Chen, Kuan-Ju
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Wu, John A.
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Chen, Chih
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材料科學與工程學系
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Department of Materials Science and Engineering
Nanotwinned copper (nt-Cu) has been attracting a great deal of attention in the past decades due to its excellent mechanical and electrical properties. In this study, a new approach, periodic-reverse (PR) waveforms, is adopted to electroplate nt-Cu films with highly < 111 >-oriented columnar grain microstructures. We investigate the effect of the reverse current on the microstructures of < 111 >--oriented nt-Cu films and their grain growth behavior. With proper reverse current parameters, we are able to obtain a nt-Cu film with a significantly thin transition layer, low amount of impurities, and low residual stress levels in comparison to a DC electroplated film. It is also discovered that the grain size after annealing of the nt-Cu film is related to its initial columnar grain microstructures, which can be tailored by the reverse current parameter. These results show that PR electroplating provides a promising approach in improving and controlling the microstructures and properties of nt-Cu films.
Intelligent Environmental Sensing: Fabrication of Switchable, Reusable, and Highly Sensitive Gas Sensors with Spiropyran-Grafted Anodic Aluminum Oxide Templates
(2020-06-04)
Lee, Lin-Ruei
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Karapala, Vamsi Krishna
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Lin, Yu-Liang
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He, Hung-Chieh
;
Chen, Jiun-Tai
Monitoring undesired pH deviations in the surroundings is one of the most pervasive issues of environment and industry, and developing efficient, economical, portable, and reusable membranes for pH monitoring is urgently needed. Herein, we report novel smart nanomembranes (SNMs) that are made up of anodic aluminum oxide (AAO) templates grafted with spiropyran molecules. The ultraviolet and visible light responses of the SNMs under acid vapors are investigated. Under UV irradiation, the ring-closed spiropyran on the AAO templates transform to ring-opened merocyanine, which contains phenolate oxygen and can be further protonated by acids. Such a protonation process not only shows evident color changes but also endows SNMs with pH-responsive properties, which are further investigated by UV-vis diffuse reflectance spectroscopy. Furthermore, to demonstrate the pH-responsive properties of the SNM, common volatile acids such as hydrochloric acid, nitric acid, formic acid, and acetic acid are tested. The SNM shows conspicuous sensibility, reusability, and reversibility during the processes of irradiation, protonation, and deprotonation. Therefore, the newly developed SNM can be an excellent alternative to the existing pH sensors for the detection of pH variations in environment and industry.
Plasmonic Manipulation-Controlled Chiral Crystallization of Sodium Chlorate
(2020-06-04)
Cheng, An-Chieh
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Niinomi, Hiromasa
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Omatsu, Takashige
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Ishida, Shutaro
;
Sasaki, Keiji
Plasmonic manipulation using well-designed triangular trimeric gold nanostructures achieves a giant (greater than 50%) crystal enantiomeric excess (CEE) of sodium chlorate (NaClO3). Stronger asymmetric interactions between molecule and light are pursued to reach high enantiomeric excess. The well-designed gold nanostructures immersed in a saturated NaClO3 D2O solution were irradiated with linear, left-hand, and right-hand circular polarizations of a 1064 nm continuous-wave laser. Within seconds of the start of the irradiation, an achiral metastable crystal was formed at the laser focus, and further irradiation induced a subsequent polymorphic transition to the chiral crystal. The crystal chirality is sensitive to the handedness of circular polarization, allowing for efficient enantioselectivity. The mechanisms to achieve this giant CEE are proposed based on the results of electromagnetic field analysis generated near the nanostructure by the finite element method.
A fluorescent turn-on probe for detection of hypochlorus acid and its bioimaging in living cells
(2020-06-05)
Chu, Chien-Ju
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Wu, Guan-Syuan
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Ma, Ho-I
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Venkatesan, Parthiban
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Thirumalaivasan, Natesan
Hypochlorous acid has played several functions in the biological system. However, excess HOCI can cause damage to biomolecules and result in some diseases. Accordingly, a new fluorescent probe, BSP, has been developed for fast recognition of HOCI through the HOG-induced oxidation of methyl phenyl sulfide to sulfoxide. The reaction of BSP with HOG caused a 22-fold fluorescence enhancement (quantum yield increase from 0.006 to 0.133). The detection limit of HOCI is found to be 30 nM (S/N = 3). The fluorescence enhancement is due to the suppression of the photo-induced electron transfer from the methyl phenyl sulfide moiety to BODIPY. Eventually, the cellular fluorescence imaging experiment showed that BSP could be effectively used for monitoring HOCI in living cells. (C) 2020 Elsevier B.V. All rights reserved.
Vacuum ultraviolet photolysis of CH4:O-2 ice mixtures and the formation of CO and CO2
(2020-06-05)
Chou, Sheng-Lung
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Lin, Meng-Yeh
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Huang, Tzu-Ping
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Wu, Yu-Jong
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應用化學系
Vacuum ultraviolet (VUV) photolysis of CH4:O-2 ice mixtures at 10 K using 121.6, 157, and 170-nm wavelengths was performed to examine photochemical reactions for the oxidation of hydrocarbon species. Ice samples with three component ratios were prepared: CH4-dominated (CH4:O-2 = 100:1), mixed (CH4:O-2 = 1:1), and O-2-dominated (CH4:O-2 = 1:100) ice samples. Photochemical behavior with dependence on the photolysis wavelength and component ratio was observed. In addition, the column densities of CO and CO2 formed by the VUV photolysis of the three ice samples and the abundance ratios of CO and CO2 as a function of the photon dosage and photolysis wavelength were examined. The results may imply a correlation between the unknown depletion of interstellar oxygen and the formation of CO and CO2. (C) 2020 Elsevier B.V. All rights reserved.
Formation and infrared spectra of monohydrogenated pyrenes 2-C16H11 and 4-C16H11 trapped in solid para-hydrogen
(2020-06-05)
Bahou, Mohammed
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Chou, Sheng-Lung
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Wu, Yu-Jong
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應用化學系
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應用化學系分子科學碩博班
We recorded the IR spectra of 2-C16R11 and 4-C16R11 trapped in solid para-hydrogen (p-H-2). These species were produced on the electron bombardment of p-H-2 containing pyrene (C16H10) in a small proportion during matrix deposition. IR absorption features of 1-C16H11+ and 1-C16H11 in solid p-H-2 were previously identified [J. Phys. Chem. Lett. 4 (2013) 1989]. Here, the irradiation of a similar matrix sample at 365 nm depleted 1-C(16)H(11)(+ )and 2-C16H11 and produced 1-C16H11 and 4-C16H11. In contrast, irradiation at 405 nm decreased 1-C16H11+, 2-C16H11 and 4-C16H11. The identification of the observed lines of 2-C16H11, and 4-C16H11 was supported by predictions of the vibrational wavenumbers and relative IR intensities at the B3PW91/6-311++G(2d,2p) level of theory. (C) 2020 Elsevier B.V. All rights reserved.
Manipulating magnetoelectric energy landscape in multiferroics
(2020-06-05)
Huang, Yen-Lin
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Nikonov, Dmitri
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Addiego, Christopher
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Chopdekar, Rajesh, V
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Prasad, Bhagwati
Magnetoelectric coupling at room temperature in multiferroic materials, such as BiFeO3, is one of the leading candidates to develop low-power spintronics and emerging memory technologies. Although extensive research activity has been devoted recently to exploring the physical properties, especially focusing on ferroelectricity and antiferromagnetism in chemically modified BiFeO3, a concrete understanding of the magnetoelectric coupling is yet to be fulfilled. We have discovered that La substitutions at the Bi-site lead to a progressive increase in the degeneracy of the potential energy landscape of the BiFeO3 system exemplified by a rotation of the polar axis away from the < 111 > (pc) towards the < 112 > (pc) discretion. This is accompanied by corresponding rotation of the antiferromagnetic axis as well, thus maintaining the right-handed vectorial relationship between ferroelectric polarization, antiferromagnetic vector and the Dzyaloshinskii-Moriya vector. As a consequence, La-BiFeO3 films exhibit a magnetoelectric coupling that is distinctly different from the undoped BiFeO3 films. BiFeO3 has a wide application but the impact of rare-earth substitution for the evolution of the coupling mechanism is unknown. Here, the authors reveal the correlation between ferroelectricity, antiferromagnetism, a weak ferromagnetic moment, and their switching pathways in La-substituted BiFeO3.
大學校園裡的剩食議題
(2020-06-07)
高儷玲
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Department of Communication and Technology
;
傳播與科技學系
【台灣剩食大解密】專題

剩食議題是個需要被正視的問題，大多數人認為廚餘是一種回收，因此倒廚餘並不會有愧疚感，但食物浪費卻是傷害環境的元兇之一。
數位身分證比你想像的還要危險
(2020-06-07)
詹庭瑄
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Department of Communication and Technology
;
傳播與科技學系
【資安戰的未爆彈　專題】

原本預計2020年10月全台要更換數位身分證（eID），卻因疫情嚴峻，無法順利在原訂時程引進國外的高防偽晶片技術，因而推延換發。而換發數位身分證對於台灣的必要性，需要考量到政府是否能保證資安的完整性，否則全台個資上傳網路，一但被駭，將是必是一大危機。
台灣OTT的內憂與外患
(2020-06-07)
廖玥茹
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Department of Communication and Technology
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傳播與科技學系
【OTT席捲全球　台灣準備好了嗎】專題

科技使民眾收視行為改變，線上影音平台的前景一片光明，但台灣本土OTT業者得面對大國競爭、無法律規範等困境。在OTT的巨浪下，台灣真的準備好了嗎？
山林解禁　親近山林更容易
(2020-06-07)
王冠云
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Department of Communication and Technology
;
傳播與科技學系
【向山致敬　認識台灣】專題

山脈是台灣主要的地形，認識山脈才算認識台灣。行政院所推出的山林解禁政策的五個主軸真的能讓民眾更願意親近山林嗎？
全台農夫市集在哪裡？
(2020-06-07)
邱欣誼
;
Department of Communication and Technology
;
傳播與科技學系
【台灣農夫市集知多少】專題

你知道台灣哪裡有農夫市集？又有哪些認證標章呢？農夫市集推廣農食共生、產銷履歷透明的農產品，希望在輔助在地小農之餘，也帶給民眾安心的農產品。
總編輯的話
(2020-06-07)
楊詠嵐
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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341期，總共有6篇報導。其中有3篇文化現象，2篇社會議題，1則影音新聞。本期頭題為邱于非的《跨國送養　浪浪回家的專機》，題材新穎，內容也引人入勝，對此議題的探討也足夠深入。本期其他篇專題文章也都有深入淺出的探討，值得一讀。
台灣資源班　資源卻缺乏？
(2020-06-07)
黃博暄
;
Department of Communication and Technology
;
傳播與科技學系
【台灣資源班現況】專題

資源班對於學習較為遲緩的兒童，是找回學習信心的核心場所，但現今台灣的資源班，卻可能有資源分配上面的不足，導致教學效率較不彰的問題。