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Lee H.-S.,Pohang | Park S.-S.,Pohang | Kim S.-H.,Pohang | Park Y.-J.,Pohang | And 7 more authors.
IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference | Year: 2016

The PAL-XFEL hard X-ray linac has a 716 m long gallery and tunnel for 10 GeV. Forty nine modulators are necessary in the hard X-ray gallery for an X-band linearizer, an S-band RF gun, two S-band deflectors and 45 S-band klystrons for accelerating structures. They have been installed completely from March 15, 2015 to December 30, 2015 after completing the building construction. There are 51 modulators, 178 accelerators structures, 42 SLEDs in the hard X-ray linac and the soft X-ray linac. The RF conditioning of the klystrons, SLEDs and accelerating structures were stated from November 24, 2015. We describe the PAL-XFEL system and the current status of the linac RF system. Copyright © 2016 CC-BY-3.0 and by the respective authors.

Kim D.-Y.,Pohang | Kwak E.,Pohang | Kim S.-H.,Pohang University of Science and Technology | Lee K.-H.,Pohang | And 3 more authors.
Nucleic Acids Research | Year: 2011

Daily mRNA oscillations of circadian clock genes largely depend on transcriptional regulation. However, several lines of evidence highlight the critical role of post-transcriptional regulation in the oscillations of circadian mRNA oscillations. Clearly, variations in the mRNA decay rate lead to changes in the cycling profiles. However, the mechanisms controlling the mRNA stability of clock genes are not fully understood. Here we demonstrate that the turnover rate of mouse Period3 (mPer3) mRNA is dramatically changed in a circadian phase-dependent manner. Furthermore, the circadian regulation of mPer3 mRNA stability requires the cooperative function of 5′- and 3′-untranslated regions (UTRs). Heterogeneous nuclear ribonucleoprotein Q (hnRNP Q) binds to both 5′- and 3′-UTR and triggers enhancement of translation and acceleration of mRNA decay. We propose the phase-dependent translation coupled mRNA decay mediated by hnRNP Q as a new regulatory mechanism of the rhythmically regulated decay of mPer3 mRNA. © 2011 The Author(s).

Jung K.-H.,Pohang | Jeong J.-P.,Pohang | Suh Y.-J.,Pohang
Wireless Networks | Year: 2015

Wifi tethering enables Wifi-only devices to access the Internet by sharing the WWAN (e.g., 3G and LTE) connection of a smartphone where there is no available Wifi access point. However, the current tethering schemes have a limitation as they consume a significant portion of the battery power for providing Wifi clients with the Internet connection. In this paper, we propose a new tethering scheme that reduces the energy consumption of a mobile AP (MAP) without substantial throughput and delay degradation. To improve energy efficiency, the proposed scheme adaptively adjusts the sleep and wake-up periods based on the bandwidth asymmetric feature of the MAP. Further, it provides a longer idle time enough to put the clients into a sleep mode by combining idle periods between subsequent packets, and conserves their energy as well. Our evaluation based on the prototype implementation on commercial smartphones shows that the proposed scheme reduces the energy consumption of the MAP and the client smartphones by up to 56.0 and 8.3 %, respectively. © 2014, Springer Science+Business Media New York.

Ain W.Q.,Universiti Malaysia Pahang | Faisal M.K.,Universiti Malaysia Pahang | Talari M.K.,University Technology of MARA | Darham W.,University Technology of MARA | And 5 more authors.
Journal of Materials Engineering and Performance | Year: 2016

Reported work focuses on the effect of morphology of the Fe-rich intermetallic phases on the machinability of Al-alloy containing >2wt.% Fe, obtained from automotive scrap. Effect of Mo addition on the microstructure, high-temperature impression creep and thereby the machinability of the Al-recycled alloy were studied. The machinability of the recycled alloy was estimated by investigating the built-up-edge (BUE) and surface roughness (Ra). SEM-EDS and TEM-SADP studies have shown that the crystal structure (BCC) of the Al8Fe2Si phase remained unchanged; however, Mo replaced few Fe atoms with little effect on the lattice dimension. It has been found that the addition of Mo to the recycled alloy suppresses the formation of β-phase (Al5FeSi) by suppressing the peritectic transformation of α (Al8Fe2Si) phase. Such suppression is found to improve the high-temperature creep resistance and the machinability with the increase in the Mo addition level. © 2016 ASM International

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