Browsing by Author "Lin, Y. -C."

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Annealing Effect on the Electrical Properties of La2O3/InGaAs MOS Capacitors
(2011-01-01)
Kanda, T.
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Zade, D.
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Lin, Y. -C.
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Kakushima, K.
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Ahmet, P.
The electrical characteristics of InGaAs MOS capacitors with 8-nm-thick La2O3 gate dielectrics have been measured. The effects of annealing temperature and annealing time on the interface state densities (D-it) have been extracted. It has been found that the low Dit can be achieved by lowering the annealing temperature for an extended period of time.
Characteristics of trace metals in traffic-derived particles in Hsuehshan Tunnel, Taiwan: size distribution, potential source, and fingerprinting metal ratio
(2015-01-01)
Lin, Y. -C.
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Tsai, C. -J.
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Wu, Y. -C.
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Zhang, R.
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Chi, K. -H.
Traffic emissions are a significant source of airborne particulate matter (PM) in ambient environments. These emissions contain an abundance of toxic metals and thus pose adverse effects on human health. Size-fractionated aerosol samples were collected from May to September 2013 by using micro-orifice uniform deposited impactors (MOUDIs). Sample collection was conducted simultaneously at the inlet and outlet sites of Hsuehshan Tunnel in northern Taiwan, which is the second-longest freeway tunnel (12.9 km) in Asia. This endeavor aims to characterize the chemical constituents and size distributions, as well as fingerprinting ratios of particulate metals emitted by vehicle fleets. A total of 36 metals in size-resolved aerosols were determined through inductively coupled plasma mass spectrometry. Three major groups - namely, tailpipe emissions (Zn, Pb, and V in fine mode), wear debris (Cu, Cd, Fe, Ga, Mn, Mo, Sb, and Sn), and resuspended dust (Ca, Mg, K, and Rb) - of airborne PM metals were categorized on the basis of the results of enrichment factor, correlation matrix, and principal component analysis. Size distributions of wear-originated metals resembled the pattern of crustal elements, which were predominated by super-micron particulates (PM1-10). By contrast, tailpipe exhaust elements such as Zn, Pb, and V were distributed mainly in submicron particles. By employing Cu as a tracer of wear abrasion, several inter-metal ratios - including Fe / Cu (14), Ba / Cu (1.05), Sb / Cu (0.16), Sn / Cu (0.10), and Ga / Cu (0.03) - served as fingerprints for wear debris. However, the data set collected in this work is useful for further studies on traffic emission inventory and human health effects of traffic-related PM.
COLLAGEN VI PROTECTS AGAINST NEURONAL APOPTOSIS ELICITED BY ULTRAVIOLET IRRADIATION VIA AN AKT/PHOSPHATIDYLINOSITOL 3-KINASE SIGNALING PATHWAY
(2011-06-02)
Cheng, I. H.
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Lin, Y. -C.
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Hwang, E.
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Huang, H. -T.
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Chang, W. -H.
Collagen VI, one of the extracellular matrix proteins, has been implicated in regulating cell proliferation and reducing apoptosis in several different systems. However, the role of collagen VI in the central nervous system remains unclear. In this manuscript, we demonstrated that upon ultraviolet (UV) irradiation, mouse primary hippocampal neurons specifically up-regulate the expression of Col6a1, Col6a2, and Col6a3 mRNA and secreted collagen VI protein. Augmentation of collagen VI mRNA and protein after UV irradiation may have a neuroprotective role as suggested by the fact that extracellular supplying soluble collagen VI protein, but not other collagen proteins, reduced UV induced DNA damage, mitochondria dysfunction, and neurite shrinkage. We also tried to determine the signaling molecules that mediate the protective effect of collagen VI via Western blot and inhibitor analysis. After collagen VI treatment, UV irradiated neurons increased phosphorylation of Akt and decreased phosphorylation of JNK. Inhibiting Akt/Phosphatidylinositol 3-kinases (PI3K) pathway diminished the protective effect of collagen VI. Our study suggested a potential protective mechanism by which neurons up-regulate collagen VI production under stress conditions to activate Akt/PI3K anti-apoptotic signaling pathway. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved.
Cosmogenic neutron production at Daya Bay
(2018-03-26)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
Neutrons produced by cosmic ray muons are an important background for underground experiments studying neutrino oscillations, neutrinoless double beta decay, dark matter, and other rare-event signals. A measurement of the neutron yield in the three different experimental halls of the Daya Bay Reactor Neutrino Experiment at varying depth is reported. The neutron yield in Daya Bay's liquid scintillator is measured to be Y-n = (10.26 +/- 0.86) x 10(-5), (10.22 +/- 0.87) x 10(-5), and (17.03 +/- 1.22) x 10(-5) mu(-1)g(-1)cm(2) at depths of 250, 265, and 860 meters-water-equivalent. These results are compared to other measurements and the simulated neutron yield in FLUKA and GEANT4. A global fit including the Daya Bay measurements yields a power law coefficient of 0.77 +/- 0.03 for the dependence of the neutron yield on muon energy.
Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay
(2017-06-19)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW(th) reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective Pu-239 fission fractions F-239 from 0.25 to 0.35, Daya Bay measures an average IBD yield (sigma) over bar (f) of (5.90 +/- 0.13) x 10(-43) cm(2)/fission and a fuel-dependent variation in the IBD yield, d sigma(f)/dF(239), of (-1.86 +/- 0.18) x 10(-43) cm(2)/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the Pu-239 fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1 sigma. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes U-235, Pu-239, U-238, and Pu-241. Based on measured IBD yield variations, yields of (6.17 +/- 0.17) and (4.27 +/- 0.26) x 10(-43) cm(2)/fission have been determined for the two dominant fission parent isotopes U-235 and Pu-239. A 7.8% discrepancy between the observed and predicted U-235 yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.
High throughput concurrent lookahead adaptive decision feedback equaliser
(2012-01-01)
Lin, Y. -C.
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Jou, S. -J.
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Shiue, M. -T.
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A time-domain adaptive decision feedback equaliser (ADFE) for multi-gigabit wire-line 2-pulse amplitude modulation (PAM) communication systems is proposed. The throughput rate of a conventional ADFE is limited by the loops in the circuit. This investigation develops two methods for breaking or virtually breaking these loops. The first is the method of batch mode coefficient updating (BMCU), and the second is the concurrent lookahead (CLA) method. Since the loops are broken or virtually broken, a pipeline and/or a parallel method can be applied to design a throughput-rate-unlimited ADFE. The results of a simulation of the 10GBASE-S system reveal that the proposed BMCU-based CLA ADFE has the same average signal-to-noise ratio (SNR) as the original sequential ADFE for multi-mode fibres of length 30-90 m.
Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay
(2017-01)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GW(th) nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946 +/- 0.020 (0.992 +/- 0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9 sigma deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4-6 MeV was found in the measured spectrum, with a local significance of 4.4 sigma. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.
Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay
(2017-01-01)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
;
Bishai, M.
;
Blyth, S.
A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GW(th) nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946 +/- 0.020 (0.992 +/- 0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9 sigma deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4-6 MeV was found in the measured spectrum, with a local significance of 4.4 sigma. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.
Improved measurement of the reactor antineutrino flux at Daya Bay
(2019-09-09)
Adey, D.
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An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
This work reports a precise measurement of the reactor antineutrino flux using 2.2 million inverse beta decay (IBD) events collected with the Daya Bay near detectors in 1230 days. The dominant uncertainty on the neutron detection efficiency is reduced by 56% with respect to the previous measurement through a comprehensive neutron calibration and detailed data and simulation analysis. The new average IBD yield is determined to be (5.91 +/- 0.09) x 10(-43) cm(2)/fission with total uncertainty improved by 29%. The corresponding mean fission fractions from the four main fission isotopes U-235, U-238, Pu-239, and( 241)Pu are 0.564, 0.076, 0.304, and 0.056, respectively. The ratio of measured to predicted antineutrino yield is found to be 0.952 +/- 0.014 +/- 0.023 (1.001 +/- 0.015 +/- 0.027) for the Huber-Mueller (ILL-Vogel) model, where the first and second uncertainty are experimental and theoretical model uncertainty, respectively. This measurement confirms the discrepancy between the world average of reactor antineutrino flux and the Huber-Mueller model.
Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment
(2016-10-07)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2 x 10(-4) less than or similar to vertical bar Delta m(41)(2)vertical bar less than or similar to 0.3 eV(2) mass range. The resulting limits on sin(2) 2 theta(14) are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the vertical bar Delta m(41)(2)vertical bar less than or similar to 0.2 eV(2) region.
INTERCONNECTION LOSS FROM SUBSTRATE EFFECTS ON LNA PERFORMANCE AND DESIGN ACCURACY
(2009-01-01)
Tseng, S. -C.
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Meng, C. C.
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Liao, H. -Y.
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Lin, Y. -C.
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Teng, Y. -H.
A 5.2 GHz 0.18-mu m SiGe BiCMOS low noise amplifier is implemented with guided-wave interconnections in this letter. These interconnections reduce the substrate skin and proximity effects and hence are suitable for high frequency circuits. The guided interconnections bring 1.7-dB gain and 0.55-dB noise figure enhancement for the low noise amplifier. In addition, accurate and simple design methodology relies on the complete models of components and interconnections when the poststimulation from the rc extraction is not enough for the high,frequency circuit design. The measurement results give excellent agreements with the schematic simulation. (C) 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 144-146, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23968
Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments
(2016-10-07)
Adamson, P.
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An, F. P.
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Anghel, I.
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Aurisano, A.
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Balantekin, A. B.
Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti) neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin(2) 2 theta(mu e) are set over 6 orders of magnitude in the sterile mass-squared splitting Delta m(41)(2). The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Delta m(41)(2) < 0.8 eV(2) at 95% CLs.
Measurement of electron antineutrino oscillation based on 1230 days of operation of the Daya Bay experiment
(2017-04-06)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GWth nuclear power reactors of the Daya Bay and Ling Ao nuclear power facilities served as intense sources of nu((e) over bar)'s. Comparison of the (v) over bare rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors (similar to 1500-1950 m) relative to detectors near the reactors (similar to 350-600 m) allowed a precise measurement of (v) over bar (e) disappearance. More than 2.5 million (v) over bar (e) inverse beta-decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (December, 2011-July, 2012) with a subsequent 1013 days using the complete configuration of eight detectors (October, 2012-July, 2015). The (v) over bar (e) rate observed at the far detectors relative to the near detectors showed a significant deficit, R = 0.949 +/- 0.002(stat) +/- 0.002(syst). The energy dependence of (v) over bar (e) disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle sin(2)2 theta(13) = 0.0841 +/- 0.0027(stat) +/- 0.0019(syst) and the effective neutrino mass-squared difference of broken vertical bar Delta m(ee)(2)vertical bar = (2.50 +/- 0.06(stat) +/- 0.06(syst)) x 10(-3) eV(2). Analysis using the exact three-flavor probability found Delta m(32)(2) = (2.45 +/- 0.06(stat) +/- 0.06d(syst)) x 10(-3) eV(2) assuming the normal neutrino mass hierarchy and Delta m(32)(2) = (-2.56 +/- 0.06(stat) +/- 0.06(syst)) x 10(-3) eV(2) for the inverted hierarchy.
New measurement of theta(13) via neutron capture on hydrogen at Daya Bay
(2016-04-21)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
This article reports an improved independent measurement of neutrino mixing angle theta(13) at the Daya Bay Reactor Neutrino Experiment. Electron antineutrinos were identified by inverse beta-decays with the emitted neutron captured by hydrogen, yielding a data set with principally distinct uncertainties from that with neutrons captured by gadolinium. With the final two of eight antineutrino detectors installed, this study used 621 days of data including the previously reported 217-day data set with six detectors. The dominant statistical uncertainty was reduced by 49%. Intensive studies of the cosmogenic muon-induced Li-9 and fast neutron backgrounds and the neutron-capture energy selection efficiency, resulted in a reduction of the systematic uncertainty by 26%. The deficit in the detected number of antineutrinos at the far detectors relative to the expected number based on the near detectors yielded sin(2)2 theta(13) = 0.071 +/- 0.011 in the three-neutrino-oscillation framework. The combination of this result with the gadolinium-capture result is also reported.
Search for a time-varying electron antineutrino signal at Daya Bay
(2018-11-20)
Adey, D.
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An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
A search for a time-varying (nu) over bar (e) signal was performed with 621 days of data acquired by the Daya Bay Reactor Neutrino Experiment over 704 calendar days. The time spectrum of the measured (nu) over bar (e) flux normalized to its prediction was analyzed with a Lomb-Scargle periodogram, which yielded no significant signal for periods ranging from 2 hours to nearly 2 years. The normalized time spectrum was also fit for a sidereal modulation under the Standard Model Extension (SME) framework to search for Lorentz and CPT violation (LV-CPTV). Limits were obtained for all six flavor pairs (e) over bar(mu) over bar, (e) over bar(tau) over bar, (mu) over bar(tau) over bar, (e) over bar(e) over bar, (mu) over bar(mu) over bar and (tau) over bar(tau) over bar by fitting them one at a time, constituting the first experimental constraints on the latter three. Daya Bay's high statistics and unique layout of multiple directions from three pairs of reactors to three experimental halls allowed the simultaneous constraint of individual SME LV-CPTV coefficients without assuming others contribute negligibly, a first for a neutrino experiment.
Seasonal variation of the underground cosmic muon flux observed at Daya Bay
(2018-01-01)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
The Daya Bay Experiment consists of eight identically designed detectors located in three underground experimental halls named as EH1, EH2, EH3, with 250, 265 and 860 meters of water equivalent vertical overburden, respectively. Cosmic muon events have been recorded over a two-year period. The underground muon rate is observed to be positively correlated with the effective atmospheric temperature and to follow a seasonal modulation pattern. The correlation coefficient alpha, describing how a variation in the muon rate relates to a variation in the effective atmospheric temperature, is found to be alpha(EH1) = 0 : 362 +/- 0 : 031, alpha(EH2) = 0.433 +/- 0.038 and alpha(EH3) = 0.641 +/- 0.057 for each experimental hall.
Study of the wave packet treatment of neutrino oscillation at Daya Bay
(2017-09-14)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
The disappearance of reactor (v) over bar (e) observed by the Daya Bay experiment is examined in the framework of a model in which the neutrino is described by a wave packet with a relative intrinsic momentum dispersion sigma(rel). Three pairs of nuclear reactors and eight antineutrino detectors, each with good energy resolution, distributed among three experimental halls, supply a high-statistics sample of (v) over bar (e) acquired at nine different baselines. This provides a unique platform to test the effects which arise from the wave packet treatment of neutrino oscillation. The modified survival probability formula was used to fit Daya Bay data, providing the first experimental limits: 2.38 x 10(-1)7 < sigma(rel) < 0.23. Treating the dimensions of the reactor cores and detectors as constraints, the limits are improved: 10-(14) less than or similar to sigma(rel) < 0.23, and an upper limit of sigma(rel) < 0.20 (which corresponds to sigma(x) greater than or similar to 10(-11) cm) is obtained. All limits correspond to a 95% C. L. Furthermore, the effect due to the wave packet nature of neutrino oscillation is found to be insignificant for reactor antineutrinos detected by the Daya Bay experiment thus ensuring an unbiased measurement of the oscillation parameters sin(2) 2 theta(13) and Delta m(32)(2) within the plane wave model.
Ti/Al/Ni/Cu Ohmic Contact with Low Contact Resistance and Smooth Surface Morphology for AlGaN/GaN HEMT
(2014)
Wong, Y. -Y.
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Chang, E. Y.
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Chen, Y. -K.
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Liu, S. -C.
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Lin, Y. -C.
The feasibility of replacing the Au layer in a conventional ohmic contact of Ti/Al/Ni/Au for AlGaN/GaN structure with Cu has been investigated. While the thicknesses of Ti, Al and Cu layers were fixed throughout the study, the thickness of Ni layer was varied to examine its influence on the Cu-based ohmic contacts. It is showed that the Ni layer thickness played an important role in the Ti/Al/Ni/Cu metallization for achieving low contact resistance and smooth surface morphology. With a 50-angstrom Ni layer, a low specific contact resistance (r(c)) of 1.35x10(-6) ohm-cm(2) has been realized. This result is comparable with the conventional ohmic contact (r(c) = 1.19x10(-6) ohm-cm(2)). High electron mobility transistor (HEMT) devices fabricated using both Au- and Cu-based ohmic contact exhibited similar DC characteristics, suggesting that the electrical performance did not degrade with the used of Cu in the ohmic contact. Furthermore, in the absence of Au, the surface roughening caused by Au-Al alloy in the conventional ohmic contact was also prevented. As a result, the root-mean-square roughness of the optimized Cu-based contact was only 7.62 nm as compared to 134 nm for the conventional structure.