• 제목/요약/키워드: University of Cambridge

검색결과 216건 처리시간 0.032초

Annealing Effect of Co/Pd Multilayers on Magnetic Properties During Interdifusion

  • Kim, Jai-Young;Jan E. Evetts
    • Journal of Magnetics
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    • 제2권4호
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    • pp.147-156
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    • 1997
  • An artificially modulated magnetic Co/Pd multilayer is one of the promising candidates for high density magneto-optic (MO) recording media, due to a large Kerr rotation angle in the wavelength of a blue laser beam. However, since multilayer structure, as well as amorphous structure, is a non-equilibrium state in terms of free energy and a MO recording technology is a kind of thermal recording which is conducted around Curie temperature (Tc) of the recording media, when the Co/Pd mulilayer is used for the MO recording media, changes in the magnetic properties are occurred as the amorphous structure do. Therefore, the assessment of the magnetic properties in the Co/Pd multilayer during interdiffusion is crucially important both for basic research and applications. As the parameter of the magnetic properties in this research, saturation magnetization and perpendicular magnetic anisotropy energy of the Co/Pd multilayer are measured in terms of Ar sputtering pressure and heat treatment temperature. Form the results of the research, we find out that the magnetic exchange energy between Co and Pd sublayers strongly affects the changes in the magnetic properties of the Co/Pd multilayers during the interdiffusion in ferromagnetic state. This discovery will provide the understanding of the magnetic exchange energy in the Co/Pd multilayer structure and suggest the operating temperature range for MO recording in the Co/Pd multilayer for the basic research and applications, respectively.

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In-network Distributed Event Boundary Computation in Wireless Sensor Networks: Challenges, State of the art and Future Directions

  • Jabeen, Farhana;Nawaz, Sarfraz
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권11호
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    • pp.2804-2823
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    • 2013
  • Wireless sensor network (WSN) is a promising technology for monitoring physical phenomena at fine-grained spatial and temporal resolution. However, the typical approach of sending each sensed measurement out of the network for detailed spatial analysis of transient physical phenomena may not be an efficient or scalable solution. This paper focuses on in-network physical phenomena detection schemes, particularly the distributed computation of the boundary of physical phenomena (i.e. event), to support energy efficient spatial analysis in wireless sensor networks. In-network processing approach reduces the amount of network traffic and thus achieves network scalability and lifetime longevity. This study investigates the recent advances in distributed event detection based on in-network processing and includes a concise comparison of various existing schemes. These boundary detection schemes identify not only those sensor nodes that lie on the boundary of the physical phenomena but also the interior nodes. This constitutes an event geometry which is a basic building block of many spatial queries. In this paper, we introduce the challenges and opportunities for research in the field of in-network distributed event geometry boundary detection as well as illustrate the current status of research in this field. We also present new areas where the event geometry boundary detection can be of significant importance.

Integration of BIM and Simulation for optimizing productivity and construction Safety

  • Evangelos Palinginis;Ioannis Brilakis
    • 국제학술발표논문집
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    • The 5th International Conference on Construction Engineering and Project Management
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    • pp.21-27
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    • 2013
  • Construction safety is a predominant hindrance in in-situ workflow and considered an unresolved issue. Current methods used for safety optimization and prediction, with limited exceptions, are paper-based, thus error prone, as well as time and cost ineffective. In an attempt to exploit the potential of BIM for safety, the objective of the proposed methodology is to automatically predict hazardous on-site conditions related to the route that the dozers follow during the different phases of the project. For that purpose, safety routes used by construction equipment from an origin to multiple destinations are computed using video cameras and their cycle times are calculated. The cycle times and factors; including weather and light conditions, are considered to be independent and identically distributed random variables (iid); and simulated using the Arena software. The simulation clock is set to 100 to observe the minor changes occurring due to external parameters. The validation of this technology explores the capabilities of BIM combined with simulation for enhancing productivity and improving safety conditions a-priori. Preliminary results of 262 measurements indicate that the proposed methodology has the potential to predict with 87% the location of exclusion zones. Also, the cycle time is estimated with an accuracy of 89%.

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전자스핀공명에 의한 담배연기 중 자유라디칼 측정 (Determination of Free Radicals in Mainstream Cigarette Smoke by Electron Spin Resonance)

  • 이정민;이존태;박진원;황건중
    • 한국연초학회지
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    • 제29권2호
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    • pp.146-151
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    • 2007
  • Gas phase and particulate phase radicals in mainstream cigarette smoke were determined Electron Spin Resonance(ESR) spectroscopy. The free radicals in particulate phase have been investigated by benzene extract of Cambridge Filter Pad containing the smoke condensate. Spin trapping method in conjunction with ESR was used to investigate free radicals in the gas phase of cigarette smoke. Several analytical experiments were conducted in order to determine the optimal conditions for maximum signal intensities and reproducibility of results. All the tests were optimized and normalized using the University of Kentucky 2R4F reference cigarette. The optimal conditions were 0.6 mL for analysis volume of ESR, $4{\sim}5\;mL$ for collection volume of spin-adducts, and PBN for quantification of free radicals in gas phase. The radical levels of Kentucky 2R4F cigarettes were found $2.18{\times}10^{14}\;spins/cig.$ and $2.10{\times}10^{15}\;spins/cig.$ in gas phase.

Molecular Characterization of tgd057, a Novel Gene from Toxoplasma gondii

  • Wan, Kiew-Lian;Chang, Ti-Ling;Ajioka, James W.
    • BMB Reports
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    • 제37권4호
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    • pp.474-479
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    • 2004
  • The expressed sequence tag (EST) effort in Toxoplasma gondii has generated a substantial amount of gene information. To exploit this valuable resource, we chose to study tgd057, a novel gene identified by a large number of ESTs that otherwise show no significant match to known sequences in the database. Northern analysis showed that tgd057 is transcribed in this tachyzoite. The complete cDNA sequence of tgd057 is 1169 bp in length. Sequence analysis revealed that tgd057 possibly adopts two polyadenylation sites, utilizes the fourth in-frame ATG for translation initiation, and codes for a secretory protein. The longest open reading frame for the tgd057 gene was cloned and expressed as a recombinant protein (rd57) in Escherichia coli. Western analysis revealed that serum against rd57 recognized a molecule of ~21 kDa in the tachyzoite protein extract. This suggests that the tgd057 gene is expressed in vivo in the parasite.

CAN(Controller Area Network) 프로토콜을 이용한 자동차용 전동 거울의 멀티플렉싱 제어 (Multiplexing Control of Automobile Eletromotive Mirror System using CAN(Controller Area Network) Protocol)

  • 윤상진;최군호
    • 한국산학기술학회논문지
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    • 제12권11호
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    • pp.5110-5116
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    • 2011
  • 본 논문에서는 산업용 필드 버스 프로토콜 중 신호적으로 가장 안정하다고 알려져 있는 CAN(Controller Area Network) 프로토콜을 이용하여 자동차용 전동 거울의 멀티플렉싱 제어 시스템을 제안하고자 한다. 이를 위하여 하나의 마스터 컨트롤러와 입/출력을 각각 담당하는 2개의 슬레이브 컨트롤러를 설계하여 구현하고(H/W), 이러한 각 서브 시스템 들의 효과적인 동작과 통신을 위한 Application Layer를 구현(S/W)하였다. 구현된 전체 시스템은 실제 자동차용 전동 거울에 장착하여 실험함으로써 최소한의 전장 요소들만으로 효과적인 시스템의 운용 및 제어가 가능함을 보이고자 한다.

Multi-batch core design study for innovative small modular reactor based on centrally-shielded burnable absorber

  • Steven Wijaya;Xuan Ha Nguyen;Yunseok Jeong;Yonghee Kim
    • Nuclear Engineering and Technology
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    • 제56권3호
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    • pp.907-915
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    • 2024
  • Various core designs with multi-batch fuel management (FM) are proposed and optimized for an innovative small modular reactor (iSMR), focusing on enhancing the inherent safety and neutronic performance. To achieve soluble-boron-free (SBF) operation, cylindrical centrally-shielded burnable absorbers (CSBAs) are utilized, reducing the burnup reactivity swing in both two- and three-batch FMs. All 69 fuel assemblies (FAs) are loaded with 2-cylindrical CSBA. Furthermore, the neutron economy is improved by deploying a truly-optimized PWR (TOP) lattice with a smaller fuel radius, optimized for neutron moderation under the SBF condition. The fuel shuffling and CSBA loading patterns are proposed for both 2- and 3-batch FM with the aim to lower the core leakage and achieve favorable power profiles. Numerical results show that both FM configurations achieve a small reactivity swing of about 1000 pcm and the power distributions are within the design criteria. The average discharge burnup in the two-batch core is comparable to three-batch commercial PWR like APR-1400. The proposed checker-board CR pattern with extended fingers effectively assures cold shutdown in the two-batch FM scenario, while in the three-batch FM, three N-1 scenarios are failed. The whole evaluation process is conducted using Monte Carlo Serpent 2 code in conjunction with ENDF/B-VII.1 nuclear library.

Simple Sequence Repeat (SSR) and GC Distribution in the Arabidopsis thaliana Genome

  • Mortimer Jennifer C;Batley Jacqueline;Love Christopher G;Logan Erica;Edwards David
    • Journal of Plant Biotechnology
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    • 제7권1호
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    • pp.17-25
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    • 2005
  • We have mined each of the five A. thaliana chromosomes for the presence of simple sequence repeats (SSRs) and developed custom perl scripts to examine their distribution and abundance in relation to genomic position, local G/C content and location within and around transcribed sequences. The distribution of repeats and G/C content with respect to genomic regions (exons, UTRs, introns, intergenic regions and proximity to expressed genes) are shown. SSRs show a non-random distribution across the genome and a strong association within and around transcribed sequences, while G/C density is associated specifically with the coding portions of transcribed sequences. SSR motif repeat number shows a high degree of variation for each SSR type and a high degree of motif sequence bias reflecting local genome sequence composition. PCR primers suitable for the amplification of identified SSRs have been designed where possible, and are available for further studies.

영국 명문대학의 입학전형 제도 - 면접고사를 중심으로 - (The University Entrance System in the UK: Focused on the Interview Method of four Leading Universities)

  • 유재봉
    • 비교교육연구
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    • 제22권4호
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    • pp.125-147
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    • 2012
  • 본 연구의 목적은 영국 대학 입학전형 제도를 명문대학의 면접고사를 중심으로 고찰하기 위한 것이다. 이러한 목적을 위해, 영국 중등학교 제도와 전형요소, 그리고 영국 대학입학 전형의 특징을 고찰하고, 영국 명문대학의 입학전형 방법과 면접고사에 대해 상세히 살펴보았다. 영국 대학의 입학사정은 다양한 전형 요소들을 확인하며, 이러한 작업은 모두 대학에서 요구하는 학업능력과 잠재능력을 확인하는데 초점을 둔다. 영국의 명문대학은 영국과 세계 각국의 최우수 학생들을 대상으로 잠재능력과 각 대학이 요구하는 특정 능력을 변별하기 위해 면접고사를 실시한다. 영국 대학의 면접고사는 우리나라 대학입학 전형이 어떤 인재를 선발할 것인지에 대한 기본 철학 측면과 면접고사의 본질과 신뢰도를 제고하는 실제 측면에 중요한 함의를 제공해 주고 있다.

VC-DIMENSION AND DISTANCE CHAINS IN 𝔽dq

  • ;Ruben Ascoli;Livia Betti;Justin Cheigh;Alex Iosevich;Ryan Jeong;Xuyan Liu;Brian McDonald;Wyatt Milgrim;Steven J. Miller;Francisco Romero Acosta;Santiago Velazquez Iannuzzelli
    • Korean Journal of Mathematics
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    • 제32권1호
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    • pp.43-57
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    • 2024
  • Given a domain X and a collection H of functions h : X → {0, 1}, the Vapnik-Chervonenkis (VC) dimension of H measures its complexity in an appropriate sense. In particular, the fundamental theorem of statistical learning says that a hypothesis class with finite VC-dimension is PAC learnable. Recent work by Fitzpatrick, Wyman, the fourth and seventh named authors studied the VC-dimension of a natural family of functions ℋ'2t(E) : 𝔽2q → {0, 1}, corresponding to indicator functions of circles centered at points in a subset E ⊆ 𝔽2q. They showed that when |E| is large enough, the VC-dimension of ℋ'2t(E) is the same as in the case that E = 𝔽2q. We study a related hypothesis class, ℋdt(E), corresponding to intersections of spheres in 𝔽dq, and ask how large E ⊆ 𝔽dq needs to be to ensure the maximum possible VC-dimension. We resolve this problem in all dimensions, proving that whenever |E| ≥ Cdqd-1/(d-1) for d ≥ 3, the VC-dimension of ℋdt(E) is as large as possible. We get a slightly stronger result if d = 3: this result holds as long as |E| ≥ C3q7/3. Furthermore, when d = 2 the result holds when |E| ≥ C2q7/4.