非星形成高密度銀河の運命

Tohoku University秋山正幸課

Physical Characterization of Early Galaxies in the Webb's First Deep Field SMACS J0723.3-7323

This paper highlights initial photometric analyses of JWST NIRCam imaging data in the sightline of SMACS0723, aiming to identify galaxies at redshift $z>7$. By applying a conservative Lyman-break selection followed by photometric redshift analysis and visual inspection, we identify four F090W-dropout and two F150W-dropout sources, three of which were recently confirmed in an independent spectroscopic analysis to $z=7.663$, 7.665, and 8.499. We then supplement our sample with a photometric-redshift selection, and identify five additional candidates at $7<z_{\rm phot}<13$. The NIRCam images clearly resolve all sources and reveal their sub-galactic components that were not resolved/detected in the previous imaging by Hubble Space Telescope. Our spectral energy distribution analysis reveals that the selected galaxies are characterized by young stellar populations (median age of $\sim50$ Myr) of sub-solar metallicity ($\sim0.2\,Z_\odot$) and little dust attenuation ($A_{V}\sim0.5$). In several cases, we observe extreme Hb+[OIII] lines being captured in the F444W band and seen as color excess, which is consistent with their observed high star formation rate surface density. Eight of the 11 sources identified in this study appear in at least one of the recent studies of the same fields (Adams et al., Atek et al., Donnan et al., Harikane et al., Yan et al.), implying the high fidelity of our selection. We cross-match all high-$z$ galaxy candidates presented in the five studies with our catalog and discuss the possible causes of discrepancy in the final lists.Comment: Resubmitted to ApJL after having addressed the reviewer's comments. This version includes a few updates, 1. identification of z>10 galaxy candidates, 2. estimates of number densities, and 3. comparison of the final candidates to those in other studies, all of which were pointed out during the review process. The analyses in this version are based on the latest stable version of NIRCam zeropoint

Effect of rehabilitation in patients undergoing hematopoietic stem cell transplantation

Patients undergoing hematopoietic stem cell transplantation (HSCT) tend to experience decline in physical function, mental function, and quality of life (QOL) after HSCT due to low activity caused by adverse reactions to chemotherapy used in pre-transplantation treatment and post-transplant complications. Rehabilitation for HSCT patients is effective in preventing decline in physical function, reducing fatigue, and improving QOL. A combination of aerobic exercise and strength training is recommended for exercise therapy. Risk management is also important in the implementation of exercise therapy, and the exercise intensity should be determined according to the presence of anemia, low platelet counts, or post-transplant complications. On the other hand, post-transplant complications can decrease the patient's motivation and daily activity level. A multidisciplinary approach, which includes physicians and nurses, is important to achieve early discharge from the hospital and as quick a return to society as possible

The OSIRIS Lens-Amplified Survey (OLAS) I: Dynamical Effects of Stellar Feedback in Low Mass Galaxies at z ~ 2

We introduce the OSIRIS Lens-Amplified Survey (OLAS), a kinematic survey of gravitationally lensed galaxies at cosmic noon taken with Keck adaptive optics. In this paper we present spatially resolved spectroscopy and nebular emission kinematic maps for 17 star forming galaxies with stellar masses 8 < log($M_*$/$M_{\odot}$) < 9.8 and redshifts 1.2 < z < 2.3. OLAS is designed to probe the stellar mass ($M_*$) and specific star formation rate (sSFR) range where simulations suggest that stellar feedback is most effective at driving gaseous outflows that create galaxy-wide potential fluctuations which can generate dark matter cores. We compare our kinematic data with the trend between sSFR, $M_*$ and H$\alpha$ velocity dispersion, $\sigma$, from the Feedback In Realistic Environments (FIRE) simulations. Our observations reveal a correlation between sSFR and sigma at fixed $M_*$ that is similar to the trend predicted by simulations: feedback from star formation drives star-forming gas and newly formed stars into more dispersion dominated orbits. The observed magnitude of this effect is in good agreement with the FIRE simulations, in which feedback alters the central density profiles of low mass galaxies, converting dark matter cusps into cores over time. Our data support the scenario that stellar feedback drives gaseous outflows and potential fluctuations, which in turn drive dark matter core formation in dwarf galaxies.Comment: 9 pages (5 figures) with 9 page appendix (17 figures). Accepted to Ap

Multiaxial fatigue property of type 316 stainless steel using hollow cylinder specimen under combined pull loading and inner pressure

Stress controlled multiaxial fatigue test was carried out using a hollow cylinder specimen of type 316 stainless steel. A newly developed fatigue testing machine which can apply push-pull loading and reversed torsion loading and inner pressure to the hollow cylinder specimen was employed. 5 types of cyclic loading paths were employed by combining zero to pull axial and hoop stresses: a Pull (only axial stress), an Inner-pressure (only hoop stress), an Equi-biaxial (equi-biaxial stress by axial and hoop stresses), a Square-shape (trapezoidal waveforms of axial and hoop stresses with 90-degree phase difference) and a L-shape (alternately axial stress and hoop stress) loading paths. Since directions of principal stresses are fixed in all the tests, all of the loading paths are classified into ‘proportional loading’. In the Pull, the Inner-pressure and the Equi-biaxial tests, fatigue lives can be correlated on a unique line by a maximum equivalent stress based on von Mises. On the other hand, fatigue lives in the Square-shape and the L-shape tests were reduced comparing with that in the other tests, which was caused by yielding of larger plastic deformation

Preparation and Characterization of New Materials for the Storage of Electric Energy

"Electric energy storage devices, such as lithium ion rechargeable batteries and electrochemical capacitors, are used in various equipments. They are going to be used more in various systems, for examples, electric vehicles, but for these applications better performances, such as higher power density and better rate characteristics, are strongly required. In the present thesis, new materials for these electric energy storage devices were investigated.For two materials, manganese vanadate and carbon-coated metallic tin, their synthesis procedures were established by referring to their characteristics in structure and performance for the anode of lithium ion rechargeable batteries.Manganese vanadate MnV2O6 is one of the candidates for anode materials of lithium ion rechargeable batteries, which might be possible to replace graphite (Chapter 2). Crystalline powders of anhydrous MnV2O6 were successfully synthesized at a temperature below 200℃ under autogenous hydrothermal condition and by coprecipitation method. MnV2O6 powders, which were synthesized using a high concentration solutions, more than 0.1 mol/L, gave relatively high reversible capacity as 600 mAh/g and interesting cyclic performance, reversible capacity increasing to more than initial charge capacity after 3rd or 4th cycle of charge-discharge. The powders showing this interesting performance were characterized by strong 110 diffraction peak relative to other peaks and by thin rod-like morphology. The Oxidation state of anhydrous MnV2O6 synthesized was investigated by different techniques, such as XPS, XAFS, TEM, etc.Carbon-coated metallic tin powders were prepared through the heat treatment of the powder mixtures of poly(vinyl alcohol) (PVA) as a carbon precursor, SnO2 as a Sn precursor and MgO in different mass ratios in N2 gas flow (Chapter 3). SnO2 was reduced to metal, which wetted with the surface of MgO particles and so could not flow to coagulate. After carbonization of PVA, MgO was dissolved out using 1 M HCl. The carbon-coated Sn powders was found to give a high capacity as 500 mAh/g and a stable cyclic performance as an anode of lithium ion rechargeable batteries, though they showed relatively large irreversible capacity at the first cycle of charge-discharge. The reasons for this good performance for the anode of lithium ion rechargeable batteries were a small particle size of Sn, which was possible by the existence of MgO particles during carbonization process, the inhibition of coagulation of small Sn particles during charge-discharge cycles because they are coated by carbon, and the existence of spaces neighboring to Sn metal particle in carbon shells, which could absorb a large volume expansion of Sn particle due to Li alloying during charging.Two materials, mesoporous carbons and carbon-coated metal carbides, were developed for the electrode of electrochemical capacitors for electric energy storage, by establishing the synthesis procedures and measuring their structural and electrochemical characteristics.Electric double layer formation on large surface area of activated carbons has been employed for capacitors. In the present work, novel process for the synthesis of porous carbons, rich in mesopores, from thermoplastic precursors was newly developed (Chapter 4). BET surface area of the carbons synthesized through this process reached to 2000 m2/g, even though no activation process was employed.The mixtures of MgO precursor (MgO, magnesium acetate and magnesium citrate) and thermoplastic carbon precursor (PVA, poly(ethylene terephtarate) PET and hydroxyl propyl cellulose HPC) were carbonized at 700-1000 ℃ in inert atmosphere. After carbonization, carbon was isolated by dissolution of MgO formed from its precursors using diluted acid. MgO particles formed from magnesium acetate and citrate were very fine and left a large amount of mesopores with a sharp distribution in size of around 1O and 5 nm, respectively. The mesoporous carbons synthesized gave relatively high capacity, as about 300 F/g, and excellent rate characteristics in 1 M H2S04 electrolyie. Mesopores in the electrode carbons were shown to have an important role for their rate performance.The mixtures of HPC with K2W04 and K2M004 were found to give carbon-coated tungsten carbide WC and molybdenum carbide M02C after heat treatment at 1OOO and 850 ℃, respectively (Chapter 5). Cyclic voltammogram for these carbon-coated metal carbides showed a clear box-shaped curve even in the first cycle, which was known to be characteristic for electric double layer capacitor, no redox peak being observed. The capacity was about 21O F/g, which suggested the overlap of redox capacity due to either tungsten or molybdenum hydroxide, which was formed during the first cycle of charge-discharge, to the capacity due to the formation of electric double layers on porous carbons. Carbon coating kept carbide particles small, as 30 to 100 nm, which made the transformation of carbides to hydroxides possible in the first charge-discharge cycle, and inhibited the coagulation of metal hydroxide particles during cycles of charge-discharge. Carbon-coated metal carbides thus prepared have very high capacitance based on the volume of electrode film, 500 ～ 700 F/cm3, which is much higher than about 140 F/cm3 for carbon electrode.In the present thesis, MnV206 and carbon-coated Sn fine particles were developed for anode materials of lithium ion rechargeable batteries, and also mesoporous carbons and carbon-coated WC and M02C were developed for electrode materials of electrochemical capacitors. These materials showed either larger electric energy storage and/or better charge-discharge performance than the conventional materials. These materials are believed to contribute the future development of electric energy storage devices. The process for the preparation of porous carbons from thermoplastic precursors is expected to be developed as a novel process for the production of activated carbons."蓄電デバイスは、小型電子機器に限らず様々な電源として、需要が非常に高く、新規開発や改質が早急に望まれている。このような中で、リチウムイオンニ次電池には、高容量、長寿命、高効率化が強く求められ、電極の開発、改質は非常に重要な課題として取り上げられている。また、二次電池に並んで、電気化学キャパシタが近年様々な用途に期待され、高容量化、レート特性の改良などが強く求められている。いずれのデバイスに対しても国内外で多数の報告がなされている中、未だ現状に変わる次の主流となる材料が決まらないという事実がある。これには、工業的な問題やコスト、プロセスなどいろいろな課題が存在することが大きい。そこで本研究では、電極材料のより簡便でかつ経済性の高い合成方法を開発し、それらデバイスのより高性能化に寄与することを目的とした。　複合酸化物であるMnV206は、リチウムイオンニ次電池負極材の一つとして期待されている材料である。本研究では、エネルギーコストが低く、装置が簡便な水熱法および共沈法により200℃以下という低温で、その無水物を直接合成することに成功した。得られた試料は10回目のサイクル時においても600mAh/gと比較的良好な容量が確認された。さらに0.1mol/L以上の濃度条件下で合成した試料は、3回目もしくは4回目のサイクル時に一且減少した充放電容量が初期容量近くまで回復するというサイクル特異性を見出だした。このサイクル特異性を引き起こす試料は、いずれもX線による110回折線のピーク強度が他の回折線に比べて強く出ていることが共通して確認された。その構造について各種の手法（XPS，XAFS，TEM）による解析を行った。　金属スズは、理論容量が990mAh/gと非常に高く，リチウムイオンニ次電池の負極材として注目されている。しかし、Li吸蔵時の体積膨張やサイクル寿命に限度があることなどの欠点によりそのままでは使用が難しいとされてきた。本研究では、炭素被覆した微粒子金属スズを作成することによって、リチウムイオンニ次電池の高容量および高性能化が可能であることを示した。熱可塑性樹脂をSnO2およびMgOと混合した後、不活性ガス気流中で900℃に加熱、炭素化し、MgOを希酸により溶解、除去した。SnO2は、熱処理によって金属スズに還元され、混在するMgOとの親和性から凝集が妨げられ、30から100nmの微粒子に保たれる。その電極性能は、500mAh/gとグラファイト電極より優れ、リチウム挿入による金属スズの体積膨張は、MgOの溶解後に残った空隙によって吸収されていると考えられる。　電池と並び蓄電デバイスとして、キャパシタが存在する。高比表面積を有する活性炭を電極とした電気二重層を利用したキャパシタが様々な用途に期待さている。この高表面積を持つ活性炭を作る工程は非常に複雑であり環境に与える影響も大きい。本研究では、MgO上へ炭素被覆した後、そのMgOを取り除くことで、多孔質炭素を調製する新しい活性炭の製造方法を開発することに成功した。この方法は、活性炭製造では通常では用いられない熱可塑性樹脂を使用するため、様々な樹脂を選択できる利点がある。また、得られた炭素の表面積は2000m2/g以上と非常に高く、表面積および細孔構造は、炭素前駆体およびMgO前駆体そしてそれらの混合比を選択することにより簡単に制御可能であることを見出した。特に、従来の方法では直接的には作成しにくいメソ孔を作ることができることが特徴的である。この多孔質炭素をキャパシタ電極に用いた場合300F/gと非常に高い容量が得られ、高速充放電時にも損失が少ないという利点を有することを明らかにした。　さらに、熱可塑性炭素前駆体であるヒドロキシプロピルセルロース（HPC）とK2WO4またはK2MOO4の水溶液混合物から作ったゲルを800～1100℃の温度に1時間、不活性ガス中で熱処理することによって、炭素被覆タングステン（WC）またはモリブデンカーバイド（MO2C）を作成した。このカーバイドをキャパシタの電極活物質に用い、CV測定を行ったところ、電気二重層キャパシタ特有のボックス型の挙動を描き、その容量は210F/gを示した。これは、1000m2/gを超えるような高純度活性炭の電気容量と比較しても遜色のない容量である。現在まで、金属カーバイドをキャパシタ電極に用いたという報告例はない。一方、市販のWCでは、このような容量や挙動は得られず、炭素被覆されているためカーバイドが微粒に保たれていることが有利に働いていると考えられる。これらの炭素被覆カーバイドは、電極フィルムの体積あたりの容量としては500～700F/cm3となり、炭素電極の約140F/cm3に比べると極めて高い値を示した。　以上のように、本研究では、電気エネルギー貯蔵のためのデバイスであるリチウムイオンニ次電池の負極材としてのMnV206および炭素被覆金属スズ微粒子、キャパシタの電極材としてのメソポーラス炭素、炭素被覆タングステンおよびモリブデンカーバイドの調製方法を開発した。作製した材料は、いずれも従来のものよりも高い性能（高い貯蔵容量および優れたレート特性）を示し、それぞれのエネルギー貯蔵デバイスの高性能化に対して貢献できると考えられる。また、本研究で開発した熱可塑性炭素前駆体を原料とする多孔炭の製造法は、全く画期的な方法であり、今後活性炭の新しい製造法としての展開が期待でき