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Influence of substrate misorientation on the emission and waveguiding properties of a blue (In,Al,Ga)N laser-like structure studied by synchrotron radiation microbeam X-ray diffraction

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Photonics Research 2021年第3期9卷 299-307页

作者： A.Kafar A.Sakaki R.Ishii S.Stanczyk K.Gibasiewicz y.Matsuda D.Schiavon S.Grzanka T.Suski P.Perlin M.Funato y.kawakami Department of Electronic Science and Engineering Kyoto UniversityKyoto 615-8510Japan Institute of High Pressure Physics PAS Sokolowska 29/3701-142 WarsawPoland Nichia Corporation AnanTokushima 774-8601Japan TopGaN Ltd. Sokolowska 29/3701-142 WarsawPoland

In this work, we study how an epitaxial laser-like(or superluminescent diode-like) structure is modified by intentional changes of the substrate misorientation in the range of 0.5°–2.6°. The 40 μm × 40 μm test structure with misorientation profiling was fabricated using multilevel photolithography and dry-etching. The local structural parameters were measured by synchrotron radiation microbeam X-ray diffraction, with the sampling area of below 1 μm × 1 μm. We directly obtained the relation between the misorientation and indium content in the quantum well, changing from 9% to 18%, with a high resolution(small misorientation step). We also show a good agreement of local photoluminescence emission wavelength with simulation of transition energy based on synchrotron radiation microbeam X-ray diffraction(SR-XRD) data and estimated Stokes shift. We observe that the substrate misorientation influences also the In Ga N waveguide and Al Ga N cladding composition. Still, we showed through simulation of the optical confinement factor of a full laser diode structure that good light guiding properties should be preserved in the whole misorientation range studied here. This proves the usefulness of misorientation modification in applications like broadband superluminescent diodes or multicolor laser arrays.

关键词： structure microbeam blue

自组织生长CdSe-ZnSe量子点的光致发光

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中国科学（A辑） 2000年第4期30卷 342-346页

作者：郑宏 K.Okamoto H.C.Ko y.kawakami Sg.Fujita 中国科学院长春物理研究所中国科学院激发态物理开放实验室长春130021 Venture Business Laboratory Department of Electronic Science and Engineering

利用不同温度下的光致发光和时间分辨光谱研究了生长在GaAs( 1 1 0 )衬底上的CdSe ZnSe自组织量子点的发光特性 ,发现浸润层量子阱的激子发光淬灭比量子点的淬灭过程快得多 ,量子点的激子辐射复合寿命远大于浸润层量子阱的激子复合寿命 ... 详细信息

利用不同温度下的光致发光和时间分辨光谱研究了生长在GaAs( 1 1 0 )衬底上的CdSe ZnSe自组织量子点的发光特性 ,发现浸润层量子阱的激子发光淬灭比量子点的淬灭过程快得多 ,量子点的激子辐射复合寿命远大于浸润层量子阱的激子复合寿命 .根据不同尺寸的量子点复合寿命的差异。

关键词：自组织生长光致发光硒化镉硒化锌量子点

Synthesis and Thermal Property of the Poly(silpheny-lenesiloxane)s with Functional Groups

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复旦学报（自然科学版） 2005年第5期44卷 798-799页

作者： y. kawakami Japan Advanced Institute of Science and Technology (JAIST) 1-1 Asahidai Nomi Ishikawa 923-1292 Japan

Silicon-containing polymers have been intensively studied in the past half-century, and a great number of papers, patents and books have been published on the synthesis, properties and applications. Silicon-containing polymers, especially polymers containing silicon atoms in the backbone, including some major species as polysiloxane, polysilane, polysilazane, etc. have chains constructed of alternately arranged silicon and oxygen atoms with organic groups attached to the silicon atoms, which are the most important silicon-containing polymers so far.

关键词：聚乙烯热性质功能组氢化硅烷化

MICROSCOPIC ANALySIS OF POLyCRySTALLINE MATERIAL AT HIGH TEMPERATURE

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 350-354页

作者： S.Imatani R.kawakami y.Kawano Kyoto University Sakyo-Ku Kyoto 606-8501 JapanKyoto University Sakyo-Ku Kyoto 606-8501 JapanKyoto University Sakyo-Ku Kyoto 606-8501 Japan

The microscopic analyses of polycrystalline material at high temperature were carried out. The crystal plasticity model proposed by Asaro and Needleman was applied to a polycrystal model in the finite element simulation and the crystal slip system was randomly provided for each crystal. The grain boundary sliding, which was characteristic at high temperature, was also taken into account. It was shown that the inhomo-geneous deformation develops over the polycrystal and that the strain concentration appears around the triple point of crystal grain boundary.

关键词： crystal plasticity finite element method grain boundary inho-mogeneity

Molecular processes in iron and zinc homeostasis and their modulation for biofortification in rice

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Journal of Integrative Plant Biology 2018年第12期60卷 1181-1198页

作者： yuta kawakami Navreet K.Bhullar Plant Biotechnology Department of Biology ETH Zurich

More than a billion people suffer from iron or zinc deficiencies globally. Rice(Oryza sativa L.) iron and zinc biofortification; i.e., intrinsic iron and zinc enrichment of rice grains, is considered the most effective way to tackle these deficiencies. However, rice iron biofortification, by means of conventional breeding, proves difficult due to lack of sufficient genetic variation. Meanwhile,genetic engineering has led to a significant increase in the iron concentration along with zinc concentration in rice grains. The design of impactful genetic engineering biofortification strategies relies upon vast scientific knowledge of precise functions of different genes involved in iron and zinc uptake, translocation and storage. In this review, we present an overview of molecular processes controlling iron and zinc homeostasis in rice. Further,the genetic engineering approaches adopted so far to increase the iron and zinc concentrations in polished rice grains are discussed in detail, highlighting the limitations and/or success of individual strategies. Recent insight suggests that a few genetic engineering strategies are commonly utilized for elevating iron and zinc concentrations in different genetic backgrounds, and thus, it is of great importance to accumulate scientific evidence for diverse genetic engineering strategies to expand the pool of options for biofortifying farmer-preferred cultivars.

关键词： Molecular processes in iron and zinc homeostasis and their modulation for biofortification in rice Zn

Do not curse the darkness of the spinal cord,light TDP-43

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Neural Regeneration Research 2021年第5期16卷 986-987页

作者： Kazuhide Asakawa Hiroshi Handa Koichi kawakami Department of Chemical Biology Tokyo Medical UniversityTokyoJapan Division of Molecular and Developmental Biology National Institute of GeneticsDepartment of GeneticsGraduate University for Advanced Studies(SOKENDAI)ShizuokaJapan

Cytoplasmic inc lus ions containing the transactivation response element(TAR)DNAbinding protein-43(TDP-43)aggregates are hallmarks of neurodegenerative disorders,such as amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(Arai et al.,2006;Neumann et al.,2006).Despite the well-recognized correlation between TDP-43 aggregation and neuronal degeneration,whether this relationship is causal has remained unclear.

关键词： al. degeneration TDP

Design of Electro-Functional Polymeric Systems with Siloxane Components

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复旦学报（自然科学版） 2005年第5期44卷 635-636页

作者： yusuke kawakami Japan Advanced Institute of Science and Technology (JAIST) Asahidai 1-1 Nomi Ishikawa 923-1292Japan

Siloxane derivatives have many unique static and dynamic properties like low surface free energy, incompatibility with other component, and bond flexibility. Various functional polymeric systems were designed by takin... 详细信息

关键词：聚合体热稳定性全息术硅氧烷浓缩工艺

Gas Permeation Properties of Organic-inorganic Ultrathin Membranes

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复旦学报（自然科学版） 2005年第5期44卷 740-741页

作者： H. kawakami Department of Applied Chemistry Tokyo Metropolitan University Hachioji Tokyo 192-0397 Japan

Recently, a great interest has been noted in the synthesis of inorganic membranes for gas separation. One of the candidates is a carbon molecular sieve (CMS) membrane, which is synthesized by the pyrolysis of a polymer. However, CMS membranes are very brittle and fragile. Additionally, it requires more careful handling and it is very difficult to prepare a thin CMS membrane because of its poor mechanical property. Therefore, the gas permeances of CMS membranes were not very high.

关键词：气体渗入有机隔膜无机隔膜气体分离合成方法分子结构

A modified normalized input-output minimization (Mod-NIOM) method for seismic wave propagation modeling

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Earthquake Engineering and Engineering Vibration 2010年第4期9卷 481-491页

作者： Santa Man Shrestha Hideji kawakami Eric Augustus Tingatinga Hidenori Mogi Department of Civil and Environmental Engineering Saitama University Geosphere Research Institute Saitama University Institute of Civil Engineering University of the Philippines Diliman

A new method for wave propagation modeling is introduced in this paper. By using the constraint optimization （Lagrange multiplier） method, the sum of weighted squared Fourier amplitudes is minimized when subjected to a constraint. The sum of the maximum amplitudes obtained from all output models is normalized to unity and is taken as a constraint. In this method, all the actual time histories are considered as outputs and dealt with equally. Independently of the combinations of time histories （or the first time history selected） during the analysis, the method captures the relationship of actual time histories by showing clear peaks. This paper describes the formulation of the models and illustrates the advantage of this method over the normalized input-output minimization （NIOM） method. The Mod-NIOM is then used to analyze the time histories of the Hyogoken-nanbu earthquake recorded at the Port Island vertical array site in Kobe, which suffered from liquefaction caused by the strong motions during the main shock. This method showed good correlations between the observed time histories at the site even though the surface time history was greatly modified by the liquefaction.

关键词： wave propagation constraint optimization S-wave velocity liquefaction amplification vertical array Hyogoken-nanbu earthquake