Browsing by Issue Date, starting with "2018-08-13"

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Quantum phase transitions in proximitized Josephson junctions
(2018-08-13)
Wu, Chien-Te
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Setiawan, F.
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Anderson, Brandon M.
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Hsiao, Wei-Han
;
Levin, K.
We study fermion-parity-changing quantum phase transitions (QPTs) in platform Josephson junctions. These QPTs, associated with zero-energy bound states, are rather widely observed experimentally. They emerge from numerical calculations frequently without detailed microscopic insight. Importantly, they may incorrectly lend support to claims for the observations of Majorana zero modes. In this paper, we present a fully consistent solution of the Bogoliubov-de Gennes equations for a multicomponent Josephson junction. This provides insights into the origin of the QPTs. It also makes it possible to assess the standard self-energy approximations, which are widely used to understand proximity coupling in topological systems. The junctions we consider are complex and chosen to mirror experiments. Our full proximity calculations associate the mechanism behind the QPT as deriving from a spatially extended, proximity-induced magnetic "defect." This defect arises because of the insulating region, which effects a local reorganization of the bulk magnetization in the proximitized superconductor. Our results suggest more generally that QPTs in Josephson junctions generally do not require the existence of spin-orbit coupling and should not be confused with, nor are they indicators of, Majorana physics.
Angular-Shaped 4,9-Dialkylnaphthodithiophene-Based Octacyclic Ladder-Type Non-Fullerene Acceptors for High Efficiency Ternary-Blend Organic Photovoltaics
(2018-08-14)
Cao, Fong-Yi
;
Huang, Wen-Chia
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Chang, Shao-Ling
;
Cheng, Yen-Ju
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應用化學系
An angular-shaped 4,9-didodecylnaphthodithiophene-based octacyclic ladder-type structure was developed. This new ladder-type donor (LD) was coupled with electron withdrawing IC and FIC units to form two A-LD-A type non-fullerene acceptor materials, NCIC and NCFIC. NCIC and NCFIC as the n-type acceptors are blended with a p-type donor PBDB-T to form the complementary absorption and suitable energy level alignments. The binary-blend PBDB-T:NCIC and PBDB-T:NCFIC devices achieved an efficiency of 7.3% and 7.5%, respectively. PC71BM was incorporated to form D-1:A(1):A(2) ternary blends which further strengthen the absorption at shorter wavelengths. Introduction of PC71BM not only efficiently improves the absorption but also provides multiple channels for exciton dissociation and electron transport to dramatically improve J(sc). It is interesting to find that the V-oc of the ternary-blend devices is reversely in proportional to the added amount of PC71BM. The device using the PBDB-T:NCIC:PC71BM (1:1:1 in wt %) showed an improved PCE of 8.32%. Moreover, the optimized device using the PBDB-T:NCFIC:PC71BM (1:1:1.5 in wt %) blend achieved the highest efficiency of 9.18%.
Wound Healing in Streptozotocin-Induced Diabetic Rats Using Atmospheric-Pressure Argon Plasma Jet
(2018-08-15)
Cheng, Kuang-Yao
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Lin, Zhi-Hua
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Cheng, Yu-Pin
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Chiu, Hsien-Yi
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Yeh, Nai-Lun
In this study, we used an argon-based round atmospheric-pressure plasma jet (APPJ) for enhancing wound healing in streptozotocin (STZ) induced diabetic rats. The APPJ was characterized by optical emission spectroscopy. We induced Type 1 and Type 2 diabetes in rats with different amounts of STZ combined with normal and high-fat diets, respectively. The wound area ratio of all the plasma-treated normal and diabetic groups was greatly reduced (up to 30%) compared with that of the untreated groups during healing. Histological analysis revealed faster re-epithelialization, collagen deposition, less inflammation, and a complete skin structure in the plasma-treated groups was found as compared with the untreated control groups. In addition, the new blood vessels of plasma-treated tissues decreased more than untreated tissues in the middle (Day 14) and late (Day 21) stages of wound healing. The plasma-treated wounds demonstrated more transforming growth factor beta (TGF-beta) expression in the early stage (Day 7), whereas they decreased in the middle and late stages of wound healing. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) increased after plasma treatment. In addition, plasma-treated water had a higher concentration of hydrogen peroxide, nitrite and nitrate when the plasma treatment time was longer. In summary, the proposed argon APPJ based on the current study could be a potential tool for treating diabetic wounds.
High-Temperature Insensitivity of 50-Gb/s 16-QAM-DMT Transmission by Using the Temperature-Compensated Vertical-Cavity Surface-Emitting Lasers
(2018-08-15)
Peng, Chun-Yen
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Tsai, Cheng-Ting
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Wang, Huai-Yung
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Wu, Yun-Chen
;
Shih, Tien-Tsorng
In this study, a 50-Gb/s 16-quadrature amplitude modulation discrete multitone (16-QAM-DMT) was applied to an 850-nm oxide-confined vertical-cavity surface-emitting laser (VCSEL) at various temperature ranging from 25 degrees C to 85 degrees C. This study reports the highest bit rate for directly modulated VCSELs operating at 85 degrees C, in addition to demonstrating, for the first time, 16-QAM-DMT with less dependence on slope efficiency (SE) reduction. By using a temperature-compensated VCSEL, this study determined the degradation of the bit error rate (BER) in terms of the signal-to-noise ratio. The analysis results demonstrate that the transmission quality is dominated by optical bandwidth rather than the SE. Therefore, the preleveling technique was applied for error rate recovery to reduce the BER from 6.3 x 10(-3) to 3.8 X 10(-3) with a 0.2-dB/GHz preleveling slope. Thus, a low-bandwidth system (nearly 10 GHz) was realized for high data-rate transmissions (50 Gb/s) at 85 degrees C. The 16-QAM-DMT transmission provides an effective approach to alleviating thermal problems that occur in high-speed optical communication without the requirement of any external amplification circuits.
Tailor magnetic order and spin-polarized gap states of opto-spintronic compounds by carrier mediation
(2018-08-15)
Yang, Chao-Yao
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Chiu, Yi-Hsuan
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Tsai, Kai-An
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Hsu, Hua-Shu
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Lin, Jun-Xiao
We investigate the role of carriers in the presence of oxygen vacancies (Vo) in mediating the ferromagnetic order and spin-polarized gap states of Cu-doped ZnO nanoparticles. We demonstrate the tuning of magnetic order via post-annealing under Ar/O-2. Carrier (Vo)-rich condition (Ar-treatment) is found to favor higher magnetic order of the nanoparticles with enhanced thermal stability and wide spin-polarized gap states from ultra-violet (UV) to visible energy range. Conversely, carrier (Vo)-poor condition (O-2-treatment) reduces resistance to thermal fluctuations and quenched spin-polarization due to lack of carrier mediation. The proposed method is effective to tailor the magnetic order as well as the wide polarized band-gap states, of oxide opto-spintronic compounds by finding the physical equivalency between charge carriers and spin electrons. (C) 2018 Elsevier B.V. All rights reserved.
Balancing latency and cost in software-defined vehicular networks using genetic algorithm
(2018-08-15)
Lin, Chun-Cheng
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Chin, Hui-Hsin
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Chen, Wei-Bo
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工業工程與管理學系
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Department of Industrial Engineering and Management
Software-defined vehicular network (SDVN) effectively improves programmability and flexibility of VANET through software-defined network (SDN) features. To address the latency problem, the previous work considered that vehicles access the IP network through either cellular links or ad hoc links of vehicular networks in an SDVN, in which the SDN controller can rebate the bandwidth of cellular links allocated to vehicles to reduce latency, but the cost of renting the rebated bandwidth is paid by the network provider. Then, it proposed a two stage game to optimize the rebating strategy to balance the latency requirement and the cost. However, optimization of each of the two stages may influence optimization of the other stage. As a consequence, this work proposes an improved genetic algorithm (IGA) to optimize the rebating stage in a single stage, which includes a dynamic mutation adjustment scheme to ensure solution diversity, and keeps the best chromosome so far to avoid solution damage owing to the dynamic mutation. Through simulation, the number of packets transmitted through cellular lines is positively correlated with the rebate ratio and the other parameters. In addition, the proposed IGA can significantly improve performance of searching solutions, and obtain better results than the previous work.
Energy-efficient DRX scheduling for D2D communication in 5G networks
(2018-08-15)
Liang, Jia-Ming
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Chang, Po-Yen
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Chen, Jen-Jee
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Huang, Chien-Feng
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Tseng, Yu-Chee
In recent years, intelligent devices such as smart phones and smart tablets are grown and developed rapidly. High-bandwidth media services such as live streaming, gaming and multi-user video conferencing are more and more popular. This results in spectrum resource depletion of the cellular network. To alleviate the problem, the 3rd Generation Partnership Project (3GPP) has proposed a new technology, called device-to-device (D2D) communications. However, D2D devices and direct link cellular users all share and access the same spectrum resource, thus degrading the network performance significantly due to the interference. In addition, due to the frequent communication nature of streaming and gaming services, the power consumption of devices is increasing dramatically. To mitigate above problems, this paper investigates how to improve the spectrum efficiency by well scheduling and allocating radio resource to more concurrent D2D and cellular users on the uplink direction and reduce unnecessary power consumption of devices via Discontinuous Reception (DRX) scheduling while guaranteeing users' Quality of Service (QoS). We propose an energy-efficient resource and sleep scheduling scheme. This scheme first establishes a conflict graph to maintain the transmission and interference relationship, and then tries to maximize concurrent D2D and mobile users by resource reuse. At the same time, the method also exploits DRX technology to further decrease possible interference and conserve devices' power consumption through optimizing their sleep operation. Simulation results show that our scheme can achieve better performance on system throughput, network capacity, and power saving compared to the existing schemes.
Hetero structure PNPN tunnel FET: Analysis of scaling effects on counter doping
(2018-08-15)
Joseph, H. Bijo
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Singh, Sankalp Kumar
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Hariharan, R. M.
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Priya, P. Aruna
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Kumar, N. Mohan
This paper investigates the effect of counter doping in an n-Tunneling Field Effect Transistor(nTFET). Effect of various pocket lengths between the source and the channel was investigated. A double gate structure with a 2 nm counter doped pocket provides higher rate of band-to-band tunneling and better on current, thereby increasing the device performance. Steep Subthreshold Swing (SS) of around 23 mV/dec was obtained due to larger band bending at a low operating voltage of 0.5 V. The low leakage current greatly reduces power consumption. The degree of depletion in pocket with smaller dimensions enhances device performance by achieving good electrical characteristics in both above and below threshold regimes. Increase in pocket length degrades the device performance thus affecting the subthreshold swing. (C) 2018 Elsevier B.V. All rights reserved.
AMP-activated Protein Kinase Phosphorylation of Angiotensin-Converting Enzyme 2 in Endothelium Mitigates Pulmonary Hypertension
(2018-08-15)
Zhang, Jiao
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Dong, Jianjie
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Martin, Marcy
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He, Ming
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Gongol, Brendan
Rationale: Endothelial dysfunction plays an integral role in pulmonary hypertension (PH). AMPK (AMP-activated protein kinase) and ACE2 (angiotensin-converting enzyme 2) are crucial in endothelial homeostasis. The mechanism by which AMPK regulates ACE2 in the pulmonary endothelium and its protective role in PH remain elusive. Objectives: We investigated the role of AMPK phosphorylation of ACE2 Ser680 in ACE2 stability and deciphered the functional consequences of this post-translational modification of ACE2 in endothelial homeostasis and PH. Methods: Bioinformatics prediction, kinase assay, and antibody against phospho-ACE2 Ser680 (p-ACE2 S680) were used to investigate AMPK phosphorylation of ACE2 Ser680 in endothelial cells. Using CRISPR-Cas9 genomic editing, we created gain-of-function ACE2 S680D knock-in and loss-of-function ACE2 knockout (ACE22/2) mouse lines to address the involvement of p-ACE2 S680 and ACE2 in PH. The AMPK-p-ACE2 S680 axis was also validated in lung tissue from humans with idiopathic pulmonary arterial hypertension. Measurements and Main Results: Phosphorylation of ACE2 by AMPK enhanced the stability of ACE2, which increased Ang (angiotensin) 1-7 and endothelial nitric oxide synthase-derived NO bioavailability. ACE2 S680D knock-in mice were resistant to PH as compared with wild-type littermates. In contrast, ACE2-knockout mice exacerbated PH, a similar phenotype found in mice with endothelial cell-specific deletion of AMPK alpha 2. Consistently, the concentrations of phosphorylated AMPK, p-ACE2 S680, and ACE2 were decreased in human lungs with idiopathic pulmonary arterial hypertension. Conclusions: Impaired phosphorylation of ACE2 Ser680 by AMPK in pulmonary endothelium leads to a labile ACE2 and hence is associated with the pathogenesis of PH. Thus, AMPK regulation of the vasoprotective ACE2 is a potential target for PH treatment.
Specific dissociation of core-excited pyrimidine nucleobases
(2018-08-16)
Chiang, Yu-Ju
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Lin, Yi-Shiue
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Lin, Huei-Ru
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Liu, Chen-Lin
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應用化學系
Total-ion-yield near-edge X-ray absorption fine structure spectra of pyrimidine nucleobases were recorded. The phenomenon of specific dissociation, such as a larger branching ratio of some ionic fragments at resonant excitation energies, was observed. From the details of the specific dissociation channels, the larger branching yields at pi*-resonant excitations indicate that local bond cleavages around the atom excited is responsible for producing these ions; local excitation thus plays a major role in the site-specific dissociations. Using the NEXAFS spectra, representative ions and their branching ratios, we propose some improved ways to determine the quantities of pyrimidine nucleobases in DNA and RNA. (C) 2018 Elsevier B.V. All rights reserved.
LOWER LIMB REHABILITATION SYSTEM
(2018-08-16)
Chia-Hsin Chen
;
Wei-Zen Chen
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Yi-Jen Chen
;
Li-Wei Ko
A lower limb rehabilitation system includes an analysis platform, a smart insole, a motion sensor and a brain wave sensor. The analysis platform has a deep learning model. The smart insole generates plural pressure signals through plural pressure sensors of a pressure sensing film. The smart insole includes a processing unit controlling a transmission unit to transmit the pressure signals to the analysis platform. The processing unit is connected to a power supply unit. The motion sensor generates a motion signal. The brain wave sensor is coupled with the analysis platform and detects a brain wave signal. The analysis platform inputs the pressure signals, the motion signal and the brain wave signal into the deep learning model for analyzing a gait. The deep learning model analyzes whether the gait is correct. The analysis platform generates a warning message if the gait is analyzed to be incorrect.
MicroRNA-224 down-regulates Glycine N-methyltransferase gene expression in Hepatocellular Carcinoma
(2018-08-16)
Hung, Jung-Hsien
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Li, Chung-Hsien
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Yeh, Ching-Hua
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Huang, Pin-Cheng
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Fang, Cheng-Chieh
Glycine N-methyltransferase (GNMT) is a tumor suppressor for HCC. It is down-regulated in HCC, but the mechanism is not fully understood. MicroRNA-224 (miR-224) acts as an onco-miR in HCC. This study is the first to investigate miR-224 targeting the coding region of GNMT transcript. The GNMT-MT plasmid containing a miR-224 binding site silent mutation of the GNMT coding sequence can escape the suppression of miR-224 in HEK293T cells. Expression of both exogenous and endogenous GNMT was suppressed by miR-224, while miR-224 inhibitor enhanced GNMT expression. miR-224 counteracts the effects of GNMT on the reduction of cell proliferation and tumor growth. The levels of miR-224 and GNMT mRNA showed a significant inverse relationship in tumor specimens from HCC patients. Utilizing CCl4-treated hepatoma cells and mice as a cell damage of inflammatory or liver injury model, we observed that the decreased expression levels of GNMT were accompanied with the elevated expression levels of miR-224 in hepatoma cells and mouse liver. Finally, hepatic AAV-mediated GNMT also reduced CCl4-induced miR-224 expression and liver fibrosis. These results indicated that AAV-mediated GNMT has potential liver protection activity. miR-224 can target the GNMT mRNA coding sequence and plays an important role in GNMT suppression during liver tumorigenesis.
Direct observation of the change in transient molecular structure of 9,9'-bianthryl using a 10 fs pulse UV laser
(2018-08-17)
Hashimoto, Sena
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Yabushita, Atsushi
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Kobayashi, Takayoshi
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Okamura, Kotaro
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Iwakura, Izumi
Photoexcitation of 9,9'-bianthryl has been considered to produce a locally excited (LE) state and then a charge transfer (CT) state by intramolecular charge transfer (ICT) in polar solvents. In contrast, the CT state is considered to be unstable in non-polar solvents and triggers a dipole flip-flop between the two anthracene rings. The central C-C bond between the two anthracene rings is considered to twist during relaxation in the LE state and CT state, and this was visualized in the present work using an ultrashort ultraviolet (UV) pulse. The C-C stretching frequency was recovered in a period of ca. 500 fs, which implies that the C-C bond undergoes repeated torsion back and forth in the electronic excited state. Investigation of samples in a polar solvent and a non-polar solvent indicated that ICT does not affect the torsion around the central C-C bond. (C) 2018 Elsevier B.V. All rights reserved.
Ultrafast dynamics of coherent optical phonon in a thin film of Bi3Se2Te
(2018-08-17)
Ko, Ying-Kuan
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Huang, Yan-Hao
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Le, Phuoc Huu
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Luo, Chih-Wei
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Gospodinov, Marin Mirtchev
We have performed ultrafast time-resolved spectroscopy of transient absorption for a thin film of Bi3Se2Te, in which recent study result implies the existence of topological surface state. The observed relaxation signal was attributed to the band filling and Auger recombination processes based on the pump power dependence of the signal. After the band filling, bulk-to-surface scattering is thought to proceed being mediated by phonon emission. The dynamics of the phonon was observed from the dumped oscillation appeared on the relaxation curve of the observed signal. The phase of the oscillation indicates that the phonon mode has the period of 519 +/- 3 fs in the electronic excited state. (C) 2018 Elsevier B.V. All rights reserved.
Graphene quantum dots decorated iron oxide and halloysite nanotubes for high performance supercapacitor
(2018-08-19)
Ganganboina, Akhilesh Babu
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Doong, Ruey-An
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環境工程研究所
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Institute of Environmental Engineering
Enhanced catalytic reduction of nitrophenols by sodium borohydride over highly recyclable Au@graphitic carbon nitride nanocomposites
(2018-08-19)
Binh Nguyen
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Doong, Ruey-An
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Huang, Chin-Pao
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環境工程研究所
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Institute of Environmental Engineering
Breath figure method for construction of high-aspect-ratio pores using diacetylene-labeled polystyrene
(2018-08-19)
Wang, Cheng-Heng
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Chang, Chung-Kai
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Li, Ming-Chia
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交大名義發表
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生物科技學系
Facile chemical approach to regio control synthesis of gold-BINOL hybrid nanostructures
(2018-08-19)
Reddy, Patlolla Shashank
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交大名義發表
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National Chiao Tung University
Facile manufacturing on energy-efficient devices with excellent flexibility and surface antireflection
(2018-08-19)
Ko, Fu-Hsiang
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材料科學與工程學系
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Department of Materials Science and Engineering
Unraveling the electron transport and masking properties of g-C3N4 in Ni/Fe nanoparticle for enhanced TCE dechlorination
(2018-08-19)
Sahu, Rama S.
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Doong, Ruey-An
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環境工程研究所
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Institute of Environmental Engineering