Nano-structured Catalytic Materials for Unsteady-state Reactions

Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Invited Lectur

ヘキサアルミネート系高温熱焼触媒材料の開発

Chapter1 INTRODUCTORY SURVEY Chapter2 EFFECT OF ADDITIVES ON SURFACE AREA OF OXIDE SUPPORTS Chapter3 PREPARATION OF LARGE SURFACE AREA HEXAALUMINATE FROM METAL ALKOXIDES Chapter4 CRYSTALLOGRAPHIC ANALYSIS ON THERMAL STABILITY OF HEXAALUMINATE Chapter5 MATERIAL DESIGN OF COMBUSTION CATALYST BY STRUCTURAL MODIFICATION OF HEXAALUMINATE Chapter6 HIGH TEMPERATURE CATALYTIC COMBUSTION OVER HEXAALUMINATE CATALYST Chapter7 SUMMARYMade available in DSpace on 2012-07-04T00:27:24Z (GMT). No. of bitstreams: 2 machida1.pdf: 9925492 bytes, checksum: a1afa50096e6af421ede8ea8dfead0a4 (MD5) machida2.pdf: 12158242 bytes, checksum: 38e073e69ca7e69628aa6f30047f359a (MD5) Previous issue date: 1992-01-3

Catalytic Direct Oxidation of Methane to Methanol by Redox of Copper Mordenite

Expectations for industrial implementation of direct conversion of CH4 to CH3OH are growing with the increasing demand for energy-efficient chemical processes. In this study, catalytic production of CH3OH by direct oxidation of CH4 with O2 was performed using Cu zeolite catalysts in a CH4/O2/H2O flow reaction. Among the various Cu zeolites investigated, the Cu-MOR catalyst exhibited relatively high CH3OH production with a turnover number of 7.4 molCH3OH/molCu over 24 h (CH4 conversion: 0.011%). The catalytically active Cu species and catalytic cycle were investigated by in-situ simultaneous X-ray absorption and infrared spectroscopy. The results suggest that the key to the catalytic cycle over Cu-MOR is the redox of Cu(I)/Cu(II) species. Furthermore, H2O-adsorption-included dynamic Cu species are revealed to be catalytically active

Ultrafast Control of Crystal Structure in a Topological Charge-Density-Wave Material

Optical control of crystal structures is a promising route to change physical properties including topological nature of a targeting material. Time-resolved X-ray diffraction measurements using the X-ray free-electron laser are performed to study the ultrafast lattice dynamics of VTe$_2$, which shows a unique charge-density-wave (CDW) ordering coupled to the topological surface states as a first-order phase transition. A significant oscillation of the CDW amplitude mode is observed at a superlattice reflection as well as Bragg reflections. The frequency of the oscillation is independent of the fluence of the pumping laser, which is prominent to the CDW ordering of the first-order phase transition. Furthermore, the timescale of the photoinduced 1$T^{\prime\prime}$ to 1$T$ phase transition is independent of the period of the CDW amplitude mode

Direct Imaging Explorations for Companions around Mid-Late M Stars from the Subaru/IRD Strategic Program

The Subaru telescope is currently performing a strategic program (SSP) using the high-precision near-infrared (NIR) spectrometer IRD to search for exoplanets around nearby mid/late-M~dwarfs via radial velocity (RV) monitoring. As part of the observing strategy for the exoplanet survey, signatures of massive companions such as RV trends are used to reduce the priority of those stars. However, this RV information remains useful for studying the stellar multiplicity of nearby M~dwarfs. To search for companions around such ``deprioritized" M~dwarfs, we observed 14 IRD-SSP targets using Keck/NIRC2 observations with pyramid wavefront sensing at NIR wavelengths, leading to high sensitivity to substellar-mass companions within a few arcseconds. We detected two new companions (LSPM~J1002+1459~B and LSPM~J2204+1505~B) and two new candidates that are likely companions (LSPM~J0825+6902~B and LSPM~J1645+0444~B) as well as one known companion. Including two known companions resolved by the IRD fiber injection module camera, we detected seven (four new) companions at projected separations between $\sim2-20$~au in total. A comparison of the colors with the spectral library suggests that LSPM~J2204+1505~B and LSPM~J0825+6902~B are located at the boundary between late-M and early-L spectral types. Our deep high-contrast imaging for targets where no bright companions were resolved did not reveal any additional companion candidates. The NIRC2 detection limits could constrain potential substellar-mass companions ($\sim10-75\ M_{\rm Jup}$) at 10~au or further. The failure with Keck/NIRC2 around the IRD-SSP stars having significant RV trends makes these objects promising targets for further RV monitoring or deeper imaging with JWST to search for smaller-mass companions below the NIRC2 detection limits.Comment: 16 pages, 8 figures, accepted for publication in A

シガ イカ ダイガク イガクブ フゾク ビョウイン ニオケル オーラル マネージメント システム ノ リンショウテキ ケントウ

当科では2014年から周術期口腔機能管理を目的に「オーラルマネージメントシステム」を稼働させている．2015年には患者に快適，安心，安全な周術期環境を提供することを目的とした，麻酔科医,薬剤師,歯科医師,歯科衛生士,看護師，管理栄養士,言語聴覚士など多職種からなる「周術期管理チーム」が発足し，当科はそのチームの一員として「オーラルマネージメントシステム」を使った口腔機能管理を担っている．今回われわれは，このシステムを利用して全身麻酔手術前の周術期口腔機能管理を実施した患者数の推移および依頼状況を把握するため臨床的検討を行った. 当院における2019年度の周術期口腔機能管理実施件数は1377件と2015年から比較して約1.6倍に増加し,実施率も34.5％と増加を認めた. 院内での啓蒙活動により,多職種における人々の口腔内に関する意識が高まり,周術期口腔機能管理実施件数や実施率の増加に繋がったと考えられた. その一方でマンパワーやチェア台数の不足などの課題も明らかとなった. 今回の調査結果を元に今後もシステムの発展に尽力する予定である.Since 2014, the Department of Oral and Maxillofacial Surgery at the Shiga University of Medical Science Hospital has been running an ‟Oral management system” specialized for oral management in the perioperative period. In 2015, the ‟Perioperative management team” was formed with the aim of providing a safe perioperative environment for patients. The team comprises anesthesiologists, pharmacists, dentists, dental hygienists, nurses, dietitians, speech pathologists, and other professionals, and manages the oral functions of patients. In this study, we report the statuses of requests and rate of adoption of the ‟Oral management system” in every department. In 2019, the number of cases of perioperative oral function management in our hospital was 1,377, an increase of about 1.6 times compared to 2015, and the implementation rate also increased to 34.5%. The educational activities in the hospital increased the awareness of the oral health of people in many professions, and led to an increase in the number and rate of perioperative oral function management. On the other hand, issues such as the lack of manpower and the number of chairs became apparent. Based on the results of this survey, we plan to continue our efforts to develop the system

Catalytic NO-H2-O2 reaction over Pt/Mg-Al-O prepared from PtCl62-- and Pt(NO2)42--exchanged hydrotalcites

The catalytic NO–H2–O2 reaction at low temperatures (50–130 °C) has been investigated over Pt-supported Mg–Al binary oxides, which were prepared from PtCl62− and Pt(NO2)42−–exchanged hydrotalcite(HT)-like compounds by heating at 600 °C in H2. Although the NOx conversion of both catalysts was similarly high (>80%) at around 70 °C, the Pt(NO2)42−–HT catalyst exhibited the higher selectivity to N2 (53% N2 and 47% N2O), compared to 12% N2 and 88% N2O for the PtCl62−–HT catalyst. The XANES/EXAFS spectroscopy showed that Pt prepared from PtCl62−–HT is partly oxidized due to the coordination of residual chlorides, whereas Pt(NO2)42−–HT yielded highly dispersed metallic Pt. Because of the presence of chloride strongly bound to Pt, the oxidative NO adsorption as NO2/NO3 was inhibited for PtCl62−–HT. The improved N2 selectivity with an increase of oxidative NO adsorption is in accord with the catalytic property of Na–Pt/ZSM-5 in our previous work [M. Machida, T. Watanabe, Appl. Catal. B: Environ. 52 (2004) 281.], suggesting that the N2 would be formed via NO2/NO3 intermediates