609 research outputs found
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A study of the relationship of self-concept and achievement in high school dropouts.
White organic light-emitting device based on a compound fluorescent-phosphor-sensitized-fluorescent emission layer
The authors demonstrate a combination fluorescent and phosphor-sensitized-fluorescent white organic light-emitting device (WOLED), employing the conductive host material, 4,4′4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′1,1′-biphenyl, doped with the phosphorescent green, and the fluorescent red and blue emitters, fac-tris(2-phenylpyridinato-N,C2′N,C2′) iridium (III), 4-(dicyanomethylene)-2-t2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H4H-pyran, and 4,4′4,4′-bis (9-ethy-3-carbazolvinylene)-1-1′1-1′-biphenyl, respectively. Although two fluorescent dopants are employed along with only a single phosphor, this simple structure can, in principle, achieve 100% internal quantum efficiency. In the prototype, the phosphor-sensitized WOLED exhibits total external quantum and power efficiencies of ηext,tot = 13.1±0.5%ηext,tot=13.1±0.5% and ηp,tot = 20.2±0.7 lm/Wηp,tot=20.2±0.7lm∕W, respectively, at a luminance of 800 cd/m2800cd∕m2 with Commission Internationale de L’Eclairage chromaticity coordinates of (x = 0.38(x=0.38, y = 0.42y=0.42) and a color rendering index of 79.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87798/2/143516_1.pd
Innovative Damage Control Systems Using Replaceable Energy Dissipating Steel Fuses for Cold-formed Steel Structures
This paper describes the development of innovative seismic technologies for cold-formed steel structures; a rocking steel shear wall system with replaceable energy dissipating steel fuses for low rise housing units. In this system, the fuses are placed at the base of a folded-steel sheet wall connecting an anchor bolt and the steel sheet wall. It is designed so that most of the earthquake energy can be dissipated by plastic deformation of the fuse elements, while the shear wall remains intact and resists vertical and horizontal forces caused by large earthquakes. As expected in seismic events, the fuses at the base move cyclically into plastic regions when the wall behaves in a rocking manner. As a result, the wall system is expected to show a stable energy absorption behavior. To maximize its energy absorption capability in this research, the shape of the fuse is optimized, such that a butterfly shape is employed to have a greater yielding region. To verify the seismic performance of the proposed system, static shear wall tests and earthquake response analyses were respectively conducted. It was confirmed, with both results, that the developed fuses have high energy absorbing capacity and the rocking shear wall systems using them also have high seismic performance in comparison with conventional shear wall systems. The proposed system contributes to increased sustainability of the building systems through which damaged fuses are replaced after strong earthquakes
容積型膨張機における気液二相断熱膨張に関する基礎的研究
学位の種別: 課程博士審査委員会委員 : (主査)東京大学教授 鹿園 直毅, 東京大学教授 大宮司 啓文, 芝浦工業大学教授 君島 真仁, 芝浦工業大学教授 白樫 了, 芝浦工業大学准教授 長谷川 洋介University of Tokyo(東京大学
Correlated Rattling of Sodium‐Chains Suppressing Thermal Conduction in Thermoelectric Stannides
物質の熱伝導率を低減させる新機構を発見 --高性能な熱電材料開発の新たな指針に--. 京都大学プレスリリース. 2022-12-27.Tin-based intermetallics with tunnel frameworks containing zigzag Na chains that excite correlated rattling impinging on the framework phonons are attractive as thermoelectric materials owing to their low lattice thermal conductivity. The correlated rattling of Na atoms in the zigzag chains and the origin of the low thermal conductivity is uncovered via experimental and computational analyses. The Na atoms behave as oscillators along the tunnel, resulting in substantial interactions between Na atoms in the chain and between the chain and framework. In these intermetallic compounds, a shorter inter-rattler distance results in lower thermal conductivity, suggesting that phonon scattering by the correlated rattling Na-chains is enhanced. These results provide new insights into the behavior of thermoelectric materials with low thermal conductivity and suggest strategies for the development of such materials that utilize the correlated rattling
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