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Optical and magnetic properties of GaN epilayers implanted with ytterbium

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Journal of Rare Earths 2010年第6期28卷 931-935页

作者： W.M.Jadwisienczak J.Wang h.tanaka J.Wu R.Palai h.huhtinen A.Anders School of EECS Ohio UniversityAthens OH45701U.S.A Department of Physics and Institute for Functional Nanomaterials University of Puerto RicoSan JuanPuerto Rico00931-3343U.S.A Wihuri Physical Laboratory Department of Physics and AstronomyUniversity of TurkuTurkuFIN-20014Finland Lawrence Berkeley National Laboratory BerkeleyCA94720U.S.A

We have studied the optical and magnetic properties of ytterbium implanted GaN epilayer grown on (0001) sapphire by metalorganic chemical vapor by deposition (MOCVD). Samples were implanted at room temperature with Yb ions at dose 4 1015 cm-2 and energy of 150 keV. The implanted samples were annealed at 1000 C in N2 at atmospheric pressure to recover implantation damages. The photoluminescence (PL), PL excitation (PLE), and PL kinetics have been studied with continuous and pulse photo-excitations in 360-1100 nm spectral range at different temperatures. The characteristic Yb3+ ion emission spectra were observed in the spectral range between 970-1050 nm. Theoretical fittings of the experimental PL temperature and PL kinetics data suggest that Yb3+ ions are involved in at least two major luminescence centers. The PLE spectra indicate that excitation of the Yb3+ ion occurs via electron-hole pair generation and complex processes. Magnetization versus magnetic field curves shows an enhancement of magnetic order for Yb-implanted samples in 5 K to 300 K temperature range. The Yb-implanted GaN sample showing weak ferromagnetic behavior was compared with the ferromagnetic in situ doped GaYbN material.

关键词： luminescence Ⅲ-nitrides rare earth ions defects ferromagnetism rare earths

Optical Network Design Considering Transmission Equipment Failure and Maintenance of Two Transmission Lines

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Optical Network Design Considering Transmission Equipment Fa...

2005'第四届光互联网国际学术会议

作者： N.Ogino h.tanaka KDDI R＆D Laboratories Inc. Saitama356-8502 Japan KDDI R＆D Laboratories Inc. Saitama.356-8502 Japan

＜正＞The optical network is a promising approach for realizing a scalable backbone network. In backbone networks, survivability is important because great volumes of traffic incur damage from faulty equipment Various design methods for the survivable optical networks have been proposed. however, no design method considering the simultaneous maintenance of multiple transmission lines has been proposed to our knowledge. This paper proposes a design method for the survivable optical networks where multiple transmission lines sharing common transmission equipment may incur damage at the same time and two transmission lines may undergo maintenance simultaneously. A mathematical programming model to obtain the optimum lightpath arrangement is presented assuming the lightpath recovery schemes. The relation between the required transmission line capacity and the combination pattern of two transmission lines that undergo maintenance is clarified using the proposed design method.

关键词： Optical network design Transmission equipment failure Maintenance of multiple transmission lines Linear programming model

Benchmark Integral Cross Sections for Electron Impact Excitation of the n=2 States in helium

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Plasma Science and Technology 2010年第3期12卷 348-352页

作者： M.hOShINO h.KATO D.SUZUKI h.tanaka I.BRAY D.V.FURSA S.J.BUCKMAN O.INGLFSSON M.J.BRUNGER Department of Physics Sophia University Centre for Antimatter-Matter Studies Curtin University of Technology Centre for Antimatter-Matter Studies Australian National University Department of Chemistry University of IcelandScience Institute Centre for Antimatter-Matter Studies Flinders University

In this paper, we present integral cross sections （ICS） for electron impact excitation of the n = 2 levels in helium in the impact energy range of 23.5 eV to 35 eV. The ICS of each final state, 2^3S, 2^1S, 2^3P and 2^1P, has been determined by integration of the angular differential cross sections （DCS） over all of 0° to 180°, where those DCS were obtained from both our previous experiments and the extrapolation using the convergent close coupling calculation. The present experimental ICS for the optically allowed 21P transition state are also compared with those obtained from the BE f-scaling method. Very good agreement between the experimental and BE f-scaled 21P ICSs is generally found in the measured impact energy region.

关键词： low energy electron impact electronic excitations helium

Characteristic Estimation for D2O Facility of KUR with Low-Enriched Uranium Fuel

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Characteristic Estimation for D2O Facility of KUR with Low-E...

作者： Y.Sakurai h.tanaka T.Fujii Research Reactor Institute Kyoto University Graduate School of Engineering Kyoto University

INTRODUCTION:In the heavy Water Neutron Irradiation Facility(DO Facility),the neutron beams with several energy spectra are available using the neutron energy spectrum shifter and cadmium *** this facility,the researches for the wider fields,such as medicine, biology,engineering,pharmacy,etc.,have been *** as a medical use,boron neutron capture therapy(BNCT) has been performed,and the number of the clinical irradiation reached to 275 just before the KUR-operation stop in February 2006.

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随机风荷载作用下的桥梁颤振可靠性分析

土木工程学报 2003年第6期36卷 42-46,79页

作者：葛耀君项海帆 h.tanaka 同济大学加拿大握太华大学

基于现有的结构可靠性理论,通过极限状态方程建立起桥梁颤振的可靠性分析模型,并提出了用以确定桥梁颤振稳定失效概率的计算方法。其中颤振可靠性分析模型中的极限状态方程以桥梁颤振临界风速为结构抗力变量,以桥址处随机风速为荷载变... 详细信息

基于现有的结构可靠性理论,通过极限状态方程建立起桥梁颤振的可靠性分析模型,并提出了用以确定桥梁颤振稳定失效概率的计算方法。其中颤振可靠性分析模型中的极限状态方程以桥梁颤振临界风速为结构抗力变量,以桥址处随机风速为荷载变量。本文采用一次二阶矩理论的几种失效概率计算方法对主跨602m的上海杨浦大桥进行了颤振失效概率计算。

关键词：随机风荷载桥梁颤振可靠性分析一次二阶矩

Interaction Between Radiation Defects and hydrogen Studied by Positron Annihilation Spectroscopy

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Interaction Between Radiation Defects and Hydrogen Studied b...

作者： h.Tsuchida h.tanaka A.Itoh T.Yoshiie Q.Xu Quantum Science and Engineering Center Graduate School of EngineeringKyoto University Depertment of Nuclear Engineering Kyoto University Research Reactor Institute Kyoto University

INTRODUCTION:hydrogen effect on void nucleation is important subjects in research of nuclear reactor *** is known to be produced in materials irradiated with a fast neutron via the nuclear reaction(n, p).The hydrogen is trapped in radiation *** induces significant mechanical property *** present many studies have been carried out on interaction of hydrogen with vacancy ***,hydrogen effect on the initial stage of growth of vacancy defects,

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Stabilization of a high-order harmonic generation seeded extreme ultraviolet free electron laser by time-synchronization control with electro-optic sampling

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high Power Laser Science and Engineering 2015年第2期3卷 1-10页

作者： h.Tomizawa T.Sato K.Ogawa K.Togawa T.tanaka T.hara M.Yabashi h.tanaka T.Ishikawa T.Togashi S.Matsubara Y.Okayasu T.Watanabe E.J.Takahashi K.Midorikawa M.Aoyama K.Yamakawa S.Owada A.Iwasaki K.Yamanouchi RIKEN SPring-8 Center Japan Synchrotron Radiation Research Institute RIKEN Center for Advanced Photonics Japan Atomic Energy Agency The University of Tokyo

A fully coherent free electron laser(FEL) seeded with a higher-order harmonic(hh) pulse from high-order harmonic generation(hhG) is successfully operated for a sufficiently prolonged time in pilot user experiments by using a timing drift feedback. For hhG-seeded FELs, the seeding laser pulses have to be synchronized with electron bunches. Despite seeded FELs being non-chaotic light sources in principle, external laser-seeded FELs are often unstable in practice because of a timing jitter and a drift between the seeding laser pulses and the accelerated electron bunches. Accordingly,we constructed a relative arrival-timing monitor based on non-invasive electro-optic sampling(EOS). The EOS monitor made uninterrupted shot-to-shot monitoring possible even during the seeded FEL operation. The EOS system was then used for arrival-timing feedback with an adjustability of 100 fs for continual operation of the hhG-seeded FEL. Using the EOS-based beam drift controlling system, the hhG-seeded FEL was operated over half a day with an effective hit rate of 20%–30%. The output pulse energy was 20 μJ at the 61.2 nm wavelength. Towards seeded FELs in the water window region, we investigated our upgrade plan to seed high-power FELs with hh photon energy of 30–100 e V and lase at shorter wavelengths of up to 2 nm through high-gain harmonic generation(hGhG) at the energy-upgraded SPring-8Compact SASE Source(SCSS) accelerator. We studied a benefit as well as the feasibility of the next hhG-seeded FEL machine with single-stage hGhG with tunability of a lasing wavelength.

关键词： arrival-timing monitor electro-optic sampling(EOS)

INhIBITION OF FIBROBLAST-MEDIATED COLLAGEN GEL CONTRACTION BY GULUCOSYLCERAMIDE SYNThASE INhIBITOR

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INHIBITION OF FIBROBLAST-MEDIATED COLLAGEN GEL CONTRACTION B...

Sino--Japanese Beijing International Symposium on Burns,1998

作者： Y.Takami T.Ogata h.tanaka K.Ogo S.Shimazaki Dept.of Plastic Surgery Deptof Emergency medicineKyorin University School of MedicineTokyoJapan

Keloid and scar formation remain major problems in the field of burn *** a number of attempts have been made to regulate the scar formation by controlling fibroblast function,clinically useful methods to prevent and treat the scar tissue have been *** has been reported that D-threo-1-phenyl-2-palmitoylamino-3-morpholino-l-propanol (PPMP),an inhibitor of

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美国自行车联合会公路自行车运动员有氧和无氧能力的特征

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山西体育科技 1996年第2期16卷 18-24页

作者： h.tanaka 樊晋华王基福

本研究为了解美国自行车联合会中各类公路运动员有氧和无氧能力。通过38名公路自行车运动员(32名男性.6名女性)各完成一组最大吸氧量和Wingate无氧测试后,发现Ⅱ级男选手在最大吸氧量方面,无论绝对值还是相对值,都是最高的。分别比Ⅲ级... 详细信息

本研究为了解美国自行车联合会中各类公路运动员有氧和无氧能力。通过38名公路自行车运动员(32名男性.6名女性)各完成一组最大吸氧量和Wingate无氧测试后,发现Ⅱ级男选手在最大吸氧量方面,无论绝对值还是相对值,都是最高的。分别比Ⅲ级和Ⅳ级运动员高出6%和10%。这些数据分别为4.98±0.14与4.72±0.15与4.54±0.121/分。分析表明在Ⅱ级和Ⅳ级男子自行车运动员间存在显著性差异(<0.05),同时女运动员的最大吸氧量(3.37±0.13/分)明显低于男性P<0.05)。Wingate无氧测试表明,Ⅱ级男运动员无氧输出功率也最高。三者的最高输出功率分别是13.86±0.23,13.55±0.25和12.80±0.41瓦/千克,平均输出功率分别是11.22±0.18,11.06±0.15和10.40±0.30瓦/千克,Ⅱ级和Ⅲ级运动员的平均输出功率间存在明显的差异(P<0.05)。女选手的最大和平均输出功率值都明显低于对等男运动员(P<0.05)。但是,如果考虑到两性间瘦体重的不同,无氧功率结果具有非性别的一致性,另外,上述两种均未在有氧和无氧测定值间发现有必然的联系,总之,Ⅱ级自行车运动员具有较高的有氧、无氧输出功率的特征。据此,我们认为有氧、无氧能力可能是自行车运动员竞赛成绩的重要决定因素。

关键词：自行车运动员最大吸氧量 Wingate无氧测试最高输出功率平均输出功率