• Title/Summary/Keyword: Chalmers

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Preparation of High Specific Activity $^{51}Cr$

  • Kim, Taeyoung;Kim, Young-Kuk
    • Nuclear Engineering and Technology
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    • v.3 no.1
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    • pp.15-19
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    • 1971
  • High specific activity $^{51}$ Cr is mainly prepared by Szilard-Chalmers process from $K_2$CrO$_4$target. Usually the recoil atom, Cr* (III), is coprecipitated with Fe(III) as a scavenger to be separated from $K_2$CrO$_4$. A new preparation method has been developed, by adding 0.1N NaOH and $C_2$H$^{5}$ OH to the irradiated target solution, to precipitate Cr* (III) without any scavenger such as Fe(III). The new method gives the product of higher specific activity and better yield than that of other methods, in the shorter processing time. This method is compared with the conventional method and the French method, and following results are obtained: the new method gives specific activity more than twice that of the conventional method and better yield than the conventional method : the French method and the new method give similar specific activity, but yield of the new method is almost twice that of the French method.

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Phenomenal Concept Strategy and A posteriori Physicalism (현상적 개념 전략과 후험적 물리주의)

  • Kim, Hyo-eun
    • Journal of Korean Philosophical Society
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    • no.94
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    • pp.163-192
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    • 2011
  • A posteriori physicalists criticize non-physicalist arguments based on the framework of two-dimensional semantics. Most of them argue for physicalism based on the analogy between scientific identity statements and psychophysical identity statements. This paper argues for another version of aposteriori physicalism, so called physicalism employing 'phenomenal concept strategy' or 'exceptionalist strategy', which appeals to merely the nature of phenomenal concept without recourse to a semantic framework. Loar's phenomenal concept strategy employs the aspect of our recognitional ability of objects in criticizing non-physicalism, leading to the argument that phenomenal concepts are 'exceptional' in applying conceivability-possibility link. I critically examine Stoljar's, Chalmers', Raffman's criticisms against Loar's exceptionalists strategy. Loar's phenomenal concept strategy reflects well our psychological aspects surrounding the acquisition and the possession of 'phenomenal concept'. In several respects, Loar's exceptionalist version of a posteriori physicalism is the best explanation for accounting for both the explanatory gap and the a posteriority of psychophysical identity.

A Fuzzy Predictive Sliding Mode Control for High Performance Induction Motor Position Drives

  • Bayoumi E.H.E.;Nashed M.N.F.
    • Journal of Power Electronics
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    • v.5 no.1
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    • pp.20-28
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    • 2005
  • This paper presents a fuzzy predictive sliding mode control for high performance induction motor position drives. A new simplified inner-loop sliding-mode current control scheme based on a nonlinear mathematical model of an induction motor is introduced. Novel predictive fuzzy logic PI and PID controllers are used in speed and position loops, respectively. Sliding-mode current controllers and fuzzy predictive logic controllers are designed based on indirect vector control. The overall system performance is examined under different dynamic operating conditions. The performance of the drive system is robust and stable, and insensitive to parameters and operating condition variations even though non-exact system parameters are used in the implementation of the proposed controllers.

From Technological Transitions to Service Transitions : A Study of Attenuation Effects in IT Service Provisioning

  • Augustsson, Nils-Petter;Holmstrom, Jonny;Nilsson, Agneta
    • Journal of Information Technology Services
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    • v.14 no.2
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    • pp.337-354
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    • 2015
  • In a day and age when contemporary businesses are transformed, driven by a service-dominance logic and dependent upon IT, we need to understand how firms cope with technological adaptations and how such technological adaptations can lead to service adaptations. Drawing on a framework on technological transitions and an interpretive longitudinal case study of the services provided by a team within a large public IT firm, this article addresses the following questions : How do service transitions come about? Can we distinguish particular patterns in service transition processes? This research unveils how technological and social dimensions mutually constitute each other within development and implementation of service provisioning. The findings show how:(a) IT plays a fundamental role in service provisioning; (b) technological transitions are the necessary but insufficient preconditions for service transitions; and (c) there are attenuation effects when it comes to the move from technology transition to service transition.

Electro-optical devices from polymer-stabilized liquid crystals with molecular shape polarity

  • Kim, Sang-Hwa;Chien, Liang Chy;Komitov, Lachezar
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.839-842
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    • 2004
  • We present a fast-switching electro-optical device based on flexoelectro-optic effect in short pitch cholesterics oriented in uniform lying helix texture. The device has two operating modes: amplitude and phase modulation mode. The amplitude modulation mode is a fast in-plane switching of the device optic axis that enables to achieve a high percent of modulation of the transmitted light intensity whereas the phase mode gives a continuous change of the refractive index and thus of the phase shift of the transmitted light. By using a small concentration of diacrylate monomer and selecting the illumination conditions we have been able to create a inhomogeneous polymeric network mostly localized at both substrate surfaces and stabilize the two switching modes.

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A parametric study of the meso-scale modelling of concrete subjected to cyclic compression

  • Rempling, Rasmus;Grassl, Peter
    • Computers and Concrete
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    • v.5 no.4
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    • pp.359-373
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    • 2008
  • The present parametric study deals with the meso-scale modelling of concrete subjected to cyclic compression, which exhibits hysteresis loops during unloading and reloading. Concrete is idealised as a two-dimensional three-phase composite made of aggregates, mortar and interfacial transition zones (ITZs). The meso-scale modelling approach relies on the hypothesis that the hysteresis loops are caused by localised permanent displacements, which result in nonlinear fracture processes during unloading and reloading. A parametric study is carried out to investigate how aggregate density and size, amount of permanent displacements in the ITZ and the mortar, and the ITZ strength influence the hysteresis loops obtained with the meso-scale modelling approach.

Printed Active-Matrix Displays

  • Burns, S.E.;Kuhn, C.;Jacobs, K.;Ramsdale, C.;Arias, A.C.;Watts, J.;Etchells, M.;Chalmers, K.;Devine, P.;Murton, N.;Norval, S.;King, J.;Mills, J.;Sirringhaus, H.;Friend, R.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.227-229
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    • 2003
  • We present a process for printing active matrix displays. In this process, transistors are fabricated using soluble semi-conducting and conducting materials. Accurate definition of the transistor channel and other circuit components is achieved by direct inkjet printing combined with surface energy patterning. We present results on our 4,800 pixel, 50 dpi, active matrix displays.

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Approaching Carbon-free Energy to Act on Climate Change (해외 원자력 전문가 좌담회 - 기후 변화 대응을 위한 탈탄소 에너지로의 접근)

  • 한국원자력산업회의
    • Nuclear industry
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    • v.36 no.4
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    • pp.33-45
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    • 2016
  • '기후 변화 대응을 위한 탈탄소 에너지로의 접근'을 주제로 한 해외 원자력 전문가 좌담회가 4월 20일 부산 BEXCO 컨벤션홀에서 열렸다. 한국원자력문화재단이 주최한 이번 좌담회는 당일 열린 '2016 한국원자력연차대회'에 참석한 해외 원자력 전문가를 초청하여 마련된 것으로, 민계홍 한국원자력산업회의 상근부회장(좌장 사회), 김호성 한국원자력문화재단 이사장, Geoffrey Rothwell OECD/NEA 수석경제연구원, Tomas $K{\aa}berger$ 스웨덴 Chalmers 공대 에너지정책학과 교수, Rashid Sarkar 방글라데시 공대 기계공학부 교수(원자력위원회 위원장 내정자) 등 원자력 전문가들이 참석하여 2시간에 걸쳐 의견을 나누었다. 좌담회 전문을 게재한다.

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Definition of Antenna Diversity Gain in User-Distributed 3D-Random Line-of-Sight

  • Kildal, Per-Simon;Carlberg, Ulf;Carlsson, Jan
    • Journal of electromagnetic engineering and science
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    • v.13 no.2
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    • pp.86-92
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    • 2013
  • The present paper defines diversity gain for stationary users. This deals in particular with gathering the received signal statistics over possible user positions and orientations in space rather than over time, and to define a meaningful diversity gain related to the cumulative improvement of the performances of the 1% users with the worst receiving conditions. The definition is used to evaluate diversity gain for some typical small antennas in an extreme environment with only line-of-sight (LOS). The LOS environment is regarded as user-distributed 3D-random LOS caused by the statistics of an ensemble of stationary users with arbitrary orientations in the horizontal plane (2D), and with arbitrary orientations of their wireless devices in the vertical plane. Thus, an overall 3D-random distribution of user orientation is assumed.

Computer Simulation of a Train Exiting a Tunnel through a Varying Crosswind

  • Krajnovic, S.
    • International Journal of Railway
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    • v.1 no.3
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    • pp.99-105
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    • 2008
  • Flow around an ICE2 high-speed train exiting a tunnel under the influence of a wind gust has been studied using numerical technique called detached eddy simulation. A wind gust boundary condition was derived to approximate previous experimental observations. The body of the train includes most important details including bogies, plugs, inter-car gaps and rotating wheels on the rail. The maximal yawing and rolling moments which possibly can cause a derailment or overturning were found to occur when approximately one third and one half of the train, respectively, has left the tunnel. These are explained by development of a strong vortex trailing along the upper leeward edge of the train. All aerodynamic forces and moments were monitored during the simulation and the underlying flow structures and mechanisms are explained.

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