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近赤外分光法による積雪の物理情報計測
Get PDFWe demonstrated experimentally that the diffuse reflectance of snowpack is proportional to the ratio of snow density to snow grain size in the near infrared region where multiple absorption peaks by ice appear.However,it remained to determine these two physical quantities of snowpack separately.In this study,we performed data processing and principal component analysis that focused only on the effect of absorption,excluding the effect of scattering by snow grains,and demonstrated the possibility of determining snow grain size independently from the NIR diffuse reflectance spectrum of snow
Simultaneous improvements of thermal efficiencies and smoke emissions in semi-premixed diesel combustion with dual-injectors and a spatially divided combustion chamber
Get PDFTo simultaneously establish the high thermal efficiencies and the low smoke emissions in the semi-premixed diesel combustion with a twin peaked heat release consisting of the first-stage premixed combustion and the second-stage spray diffusive combustion, a combination of dual-injectors and a newly designed divided combustion chamber was proposed and the combustion characteristics were investigated. The divided chamber with a lip at the middle of the side wall can prevent the second fuel spray from entering the burned region of the premixture from the first-stage injection, realizing a suitable spatial distribution of spray flames and suppressing the soot formation. The dual-injectors can independently provide the fuel sprays into the upper and the lower layers of the divided chamber with the optional quantities and timings for the first and second injections, establishing the optimum combustion phasing. The distributions of the equivalence ratios and the soot formation characteristics in the divided chamber as well as in an ordinary re-entrant chamber as a reference were analysed with CFD simulations, showing that the soot formation is smaller in the divided chamber. The second-stage spray diffusive combustion is improved as well as the late afterburning and the combustion duration are reduced with the suppression of interference between the spray flames in the divided chamber. The cooling loss in the divided chamber is smaller due to the weaker gas motion and the lower heat transfer coefficient. The experiments also showed that the thermal efficiencies are better and the smoke emissions are lower in the divided chamber at medium loads. However, at higher loads, the smoke emissions increase due to the offset injector arrangement, and the CFD analysis showed that lower smoke emissions can be expected with optimization of the injector arrangement to locate the injector for the second fuel injection at the centre of cylinder
ベイズ最適化を用いたNRDガイドスタブ型フィルタの設計
Get PDF現在，ミリ波応用に関する研究が盛んに行われている．ミリ波集積回路のプラットホームとして，低損失な非放射伝送路である非放射誘電体線路(NRDガイド)は有望な候補の一つであり，回路の構成要素となる様々な高性能なNRDガイド素子を効率的に設計することが求められている．そのためには，計算機シミュレーションを用いた自動最適設計法が有用であり，トポロジー最適設計法やモザイク状素子の最適化により素子の最適設計が実現されている．一方で，こうした手法は構造が複雑化しやすいという課題もある．本検討では，基本構造としてスタブ型のNRDガイド素子を考え，目標の特性を実現する素子の寸法最適化を行う．最適化では大域的な解探索をいかに効率的に行えるかが重要であり，過去の探索点から特性が改善される可能性の高い点を効率的に推定できるベイズ最適化を採用する
Electrochromic durability and color variation of thickness-controlled nanosheet-structured nickel-cobalt oxide thin films
Get PDFOwing to their electrochromic performance, hierarchically structured transition-metal oxides have promising energy-saving device applications. In this study, nanosheet-structured nickel-cobalt (Ni-Co) oxide thin films were prepared via facile processes under simple solution conditions and were used as energy-saving electrochromic materials. As the growth time increased from 1.5 h to 8 h, the film thickness increased from ~ 0.7 μm to ~ 1.3 μm, and the porous nanosheet-like structures were more uniformly distributed throughout the thin film. At the 1000th cyclic voltammetry (CV) cycle (scan rate = 50 m/V), the in situ transmittance variation ( ΔT ) and optical density ( ΔOD ) of an Ni-Co oxide thin film grown for 8 h were ~ 49% and ~ 0.71 at a wavelength of 700 nm, respectively, which were better than those of samples grown for 1.5 h ( ΔT of ~ 26%, ΔOD of ~ 0.19) and 3 h ( ΔT of ~ 46%, ΔOD of ~ 0.61). However, the Ni-Co oxide thin-film samples grown for 1.5 h and 3 h had good electrochromic durability over 1000 cycles, with reversibility of 0.99. These Ni-Co oxide thin films exhibited tunable color modulation in the bleached and colored states, along with fast switching time (< 4 s) and excellent coloration memory effects
砂糖水を用いた新しい人工蜃気楼教材の開発
No full textA mirage is an atmospheric optical phenomenon caused by the refraction of light due to differences in air density. It is known that the density difference between water and aqueous solutions such as sugar water or salt water can be used to reproduce the same situation as when a mirage occurs. In this paper, we propose an artificial mirage teaching material using gelatin. We also propose an artificial mirage using white LED light
未固結の軟岩層を有する無加川流域における土砂輸送の実態把握
Get PDF北海道東部に位置する常呂川水系無加川上流域では，2016年8月出水時に表層砂礫が一掃され，下層に存在していた侵食抵抗の小さい軟岩(火山灰層)が広範囲にわたり露出して急激な河床低下が生じ，橋梁の架け替えに至った．一方，岩盤露出区間より上流側は主に砂礫床であり，土砂供給の要因である河岸侵食が散見された．最上流には砂防ダムが存在するが，満砂状態となっており，その直下流では河床低下は生じていない．また，下流域では河床低下対策が実施されており，近年土砂堆積が進んでいる．以上から，最上流域には下流へ供給される砂礫が十分存在し，下流域では砂礫が堆積する一方で，堆積せず露岩拡大が生じている区間が存在する．地質状況より，無加川と並行して流れ，河床低下の生じていない常呂川上流域には安山岩，無加川上流域には一般的に強度の劣る凝灰岩が主に分布し，土砂生産源の質が異なる．本研究では，河床材料の質の違いによる土砂輸送の実態を明らかにし，適切な土砂管理のためには，上流から供給される礫の強度の把握も重要な事項であることを示した
Annual Report of Open Facility Center Kitami Institute of Technology Vol.22
Get PDF◆巻頭言 センター長 大津 直史
◆最近の動向 副センター長 白川 和哉
◆研究紹介
「亜硝酸塩系耐寒促進剤の添加によるセメント系複合材料の水和生成物と初期強度発現の相関関係」
地域未来デザイン工学科 崔 希燮…1
◆共同利用機器の紹介
「蛍光顕微鏡（BZ-X710）」
地域未来デザイン工学科 新井 博文…6
◆研究成果一覧…7
◆主要設置機器…49
◆活動報告…50
◆編集後記…52othe
Structure comparison of heme-binding sites in heme protein predicted by AlphaFold3 and AlphaFold2
Get PDFAlphaFold3 can predict protein–ligand complex structures. In this study, we examined the accuracy of prediction of heme–protein interactions by AlphaFold3. AlphaFold3 succeeded in predicting heme–protein interactions for most heme proteins except for those without homologous proteins in the Protein Data Bank. Our comparison of predictions by AlphaFold3 and AlphaFold2 suggests that heme–protein structures can be predicted from amino acid sequences of proteins alone using AlphaFold2
Random invariant densities for Markov operator cocycles and random mean ergodic theorem
Get PDFIn this paper, we consider random invariant densities and the mean ergodic theorem for Markov operator cocycles which are applicable to quenched type random dynamical systems. We give necessary and sufficient conditions for the existence of random invariant densities for Markov operator cocycles and establish the mean ergodic theorem for generalized linear operator cocycles over a weakly sequentially complete Banach space. The advantage of the result is that we show the implication of weak precompactness for almost every environment to strong convergence in the global sense