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Twisted fiber microfluidics:a cutting-edge approach to 3D spiral devices

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Microsystems & Nanoengineering 2024年第1期10卷 193-202页

作者： Shunsuke Kato Daniel W.Carlson Amy Q.Shen Yuanyuan Guo Department of Electrical Information and Physics EngineeringSchool of EngineeringTohoku UniversityAoba-kuSendai 980-8579 MiyagiJapan Micro/Bio/Nanofluidics Unit Okinawa Institute of Science and TechnologyOnnaKunigami-gun 904-0495 OkinawaJapan Frontier Research Institute for Interdisciplinary Sciences(FRIS) Tohoku UniversityAoba-kuSendai 980-0845 MiyagiJapan Graduate School of Biomedical Engineering Tohoku UniversityAoba-kuSendai 980-8579 MiyagiJapan Department of Physiology Graduate School of MedicineTohoku UniversityAoba-kuSendai 980-8575 MiyagiJapan

The development of 3D spiral microfluidics has opened new avenues for leveraging inertial focusing to analyze small fluid volumes,thereby advancing research across chemical,physical,and biological *** traditional straight microchannels rely solely on inertial lift forces,the novel spiral geometry generates Dean drag forces,eliminating the necessity for external fields in fluid ***,fabricating 3D spiral microfluidics remains a labor-intensive and costly endeavor,hindering its widespread ***,conventional lithographic methods primarily yield 2D planar devices,thereby limiting the selection of materials and geometrical *** address these challenges,this work introduces a streamlined fabrication method for 3D spiral microfluidic devices,employing rotational force within a miniaturized thermal drawing process,termed as *** innovation allows for rapid prototyping of twisted fiber-based microfluidics featuring versatility in material selection and heightened geometric *** validate the performance of these devices,we combined computational modeling with microtomographic particle image velocimetry(uTPiM)to comprehensively characterize the 3D flow *** results corroborate the presence of a steady secondary flow,underscoring the effectiveness of our *** 3D spiral microfluidics platform paves the way for exploring intricate microflow dynamics,with promising applications in areas such as drug delivery,diagnostics,and lab-on-a-chip systems.

关键词： thereby straight twisted

Oxidation behavior and improvement in nonflammability of LPSO-type Mg–Zn–Y–Sr alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 742-749页

作者： Shin-ichi Inoue Kazumasa Iwanaga Yoshihito Kawamura Magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan Department of Materials Science Graduate School of Science and TechnologyKumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

Mg_(97)Zn_(1)Y_(2)alloys with high ignition temperatures were developed by adding *** addition of Sr resulted in the formation of a uniform and thin Y_(2)O_(3)***–Zn–Y alloys containing at least 0.25 at.%Sr exhibited ignition temperatures of 1270–1320 *** a result of EDS measurement,Sr was found to be concentrated in the Y_(2)O_(3)*** addition,a mixed film of MgO and Sr O formed on the outer layer in the 1.5 at.%Sr-containing Mg_(97)Zn_(1)Y_(2)*** findings suggest that the uniform and thin Y_(2)O_(3)film that maintains high soundness at high temperatures was formed owing to valence control and the formation of a protective outer oxide film.

关键词： Magnesium alloy Yttrium Strontium High-temperature oxidation Nonflammability

How are multiple satellites seen from the ground? Relative apparent motion and formation stabilization

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Astrodynamics 2024年第1期8卷 121-134页

作者： Kenta Nakajima Yasuhiro Yoshimura Hongru Chen Toshiya Hanada Department of Aeronautics and Astronautics Kyushu University744 Motooka Nishi-kuFukuoka819-0395Japan

This paper answers how multiple satellites are seen from the ground. This question is inspired by space-advertising, a public exhibition in the night sky using a dot matrix of satellites that are bright enough to be seen by the naked eye. Thus, it is important for space advertisement that the specific dot matrix is seen. Moreover, the stability of the dot matrix during a visible span is very valuable. To stabilize the dot matrix, this study formulates an apparent position of a dot from a representative dot seen from the ground. The formulation, linear functions of a set of relative orbital elements, reveals the appearance of the dot matrix. The proposed relative variable in the formulation drives the instability of the dot matrix, thereby revealing an initial stable configuration of deputies from a chief. The arbitrary dot matrix designed using the configuration is stable even at low elevations without orbital control during the visible span.

关键词： formation flying relative motion stabilization astrodynamics multi-apparent motions space advertisement

Evaluation of temperature dependent vortex pinning properties in strongly pinned YBa_(2)Cu_(3)O_(7-δ)thin films with Y_(2)BaCuO_(5)nanoinclusions

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Superconductivity 2024年第1期9卷 95-105页

作者： Alok K.Jha Kaname Matsumoto Tomoya Horide Shrikant Saini Ataru Ichinose Paolo Mele Yutaka Yoshida Satoshi Awaji Department of Materials Science and Engineering Kyushu Institute of TechnologyTobata-kuKitakyushu 804-8550Japan Department of Mechanical and Control Engineering Kyushu Institute of TechnologyTobata-kuKitakyushu 804-8550Japan Central Research Institute of Electrical Power Industry YokosukaKanagawa 240-0196Japan College of Engineering-Innovative Global Program Shibaura Institute of TechnologyMinuma-kuSaitama 337-8570Japan Department of Energy Engineering and Science Nagoya UniversityChikusa-kuNagoya 464-8603Japan Institute for Materials Research Tohoku UniversityAoba-kuSendai 980-8577Japan

The pinning of quantized magnetic vortices in superconducting YBa_(2)Cu_(3)O_(7-δ)(YBCO or Y123)thin films with Y_(2)BaCuO_(5)(Y211)nanoinclusions have been investigated over wide temperature range(4.2-77 K).The concentration of Y211 nanoinclusions has been systematically varied inside YBCO thin films prepared by laser ablation technique using surface modified target *** pinning force density values(Fp∼0.5 TNm^(−3)at 4.2 K,9 T)have been observed for the YBCO film with moderate concentration of Y211 nanoinclusions(3.6 area%on ablation target).In addition,uniform enhancement in critical current density(J_(c))was observed in the angular dependent J_(c)measurement of YBCO+Y211 nanocomposite films.Y211 nanoinclusions have been found to be very efficient in pinning the quantized vortices thereby enhancing the in‐field J_(c)values over a wide range of *** the concentration of Y211 secondary phase into Y123 film matrix results into agglomeration of Y211 phase and observed as increased Y211 nanoparticle *** larger secondary phase nanoparticles are not as efficient pinning centers at lower temperatures as they are at higher temperatures due to substantial reduction of the coherence length at lower *** of the temperature dependence of J_(c)for YBCO+Y211 nanocomposite films has been conducted and possible vortex pinning mechanism in these nanocomposite films has been discussed.

关键词： YBCO thin film Critical current Vortex pinning Nanoscale APCs

Depositional condition of Paleoproterozoic Francevillian carbonate rocks revisited from rare earth element contents

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Geoscience Frontiers 2024年第3期15卷 31-49页

作者： Satoshi Yoshida Karen Bakakas Mayika Yuki Ishihara Mathieu Moussavou Hisashi Asanuma Tomohiko Sato Takafumi Hirata Cédric Ligna Yusuke Sawaki Amboise Edou-Minko Department of Earth Science and Astronomy The University of Tokyo3-8-1 Komaba Meguro-kuTokyo 153-8902Japan Center for Northeast Asian Studies Tohoku University41 KawauchiAoba-kuSendai 980-8576Japan Department of Geology Universitédes Sciences et Techniques de MasukuBP:90190025 FrancevilleGabon Department of Earth and Planetary Science The University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-0033Japan Geochemical Research Center The University of Tokyo7-3-1HongoBunkyo-kuTokyo 113-0033Japan Graduate School of Human and Environmental Studies Kyoto UniversityYoshida-nihonmatsuSakyo-kuKyoto 606-8501Japan Center for Fundamental Education Okayama University of Science1-1Ridai-choKita-kuOkayama CityOkayama 700-0005Japan

The Paleoproterozoic Francevillian Group in the eastern Gabonese Republic has been recently attracting increasing attention because it includes distinctive macroscopic structures interpreted as eukaryotic ***,its depositional setting and associated redox conditions need to be clearly *** clarify these,petrological studies and rare earth element(REE)abundances of carbonate rocks of the Francevillian Group in the Lastoursville basin were determined with ICP-MS coupled with a laser ablation sampling *** microscopic observations indicate that dolostones in this basin underwent the complicated diagenetic history,including sparitization,decomposition of organic matter,reduction of ferromanganese oxides,silicification,and later *** dolostones of lower Francevillian B(FB)Formation show heterogeneous textures formed by alterations during *** the alterations,changes of REE abundances and degrees of positive Y anomalies appear to have *** indicates that REE signatures in carbonate rocks can vary during *** high Mn contents in the dolostones of upper FB Formation were derived from the reduction of ferromanganese oxides in *** signatures of REE abundance in dolostones can be explained by the mixing of seawater and ferromanganese oxide *** that sense,the dolostones inherited the trace element characteristics of precursor ferromanganese oxides even after the diagenesis.Y/Ho values of the most primary parts of each sample exceed 33,the newly determined threshold value for marine carbonate rocks based on our *** magnitude of the La anomaly values also falls within the range of that of Holocene reefal *** indicate that a precursor of the dolostone of the Francevillian Group was deposited in a marine *** addition,presence of Ce anomalies in the upper FB Formation suggests that the Paleoproterozoic ocean was oxidized to such an ex

关键词： Carbonate diagenesis Francevillian Group LA-ICP-MS Seawater composition Y/Ho fractionation

Laser-assisted direct roller imprinting of large-area microstructured optical surfaces

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Microsystems & Nanoengineering 2024年第1期10卷 257-266页

作者： Keisuke Nagato Ken Takahashi Yuki Yajima Masayuki Nakao Department of Mechanical Engineering Graduate School of EngineeringThe University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan

In this study,a high-throughput fabrication method called laser-assisted direct roller imprinting(LADRI)was developed to lower the cost of nanoimprinting large-area polymer films and to address problems associated with nanoimprinting,namely,microstructural damage and precision in flatness of entire *** LADRI,the laser directly heats the microstructured surface of the roller mold,which heats and melts the surface of a polymethyl methacrylate(PMMA)film to replicate the microstructures on the mold *** this study,the effects of laser power density,scanning speed,size of the microstructures,and contact pressure on the replication speed were investigated *** replication speed increased as the power and scanning speed ***,because the film required heating until it filled the entire depth of the microstructure,an appropriate replication speed was *** result was supported by simulation of the temperature distribution inside the mold and the PMMA using transient heat conduction *** demonstrate the applications of LADRI,two different optical surfaces were replicated:an antireflection(AR)structure with conical structures sized several hundred nanometers and a lightextraction structure with a microlens array(MLA)comprising 10μm lenses,for display and illumination,*** replication degree of the MLA was governed by the contact *** flow simulation indicated that the heat conduction and flow speeds of the melted PMMA surface were comparable within several tens of *** addition,the reflectivity of the AR structure decreased from 4 to 0.5%,and the light intensity of the light-extraction structure increased by a factor of 1.47.

关键词： microstructure roller conduction

Orientation Bias of Self-Assembled Alkanes and Their Derivatives Under Dynamic Lateral Nanoconfinement Conditions

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CCS Chemistry 2024年第4期6卷 1024-1033页

作者： Conditions Lihua Yu Yuanzhi Xia Tianze Hu Brent Daelemans Steven De Feyter Department of Chemistry Division of Molecular Imaging and PhotonicsKU LeuvenB-3001 Leuven

Self-assembled molecular networks(SAMNs)formed on crystalline solid substrates result from the spontaneous arrangement of individual molecules into structured *** interaction between molecules and the substrate leads to a nonrandom orientation of SAMNs with respect to the substrate’s *** the case of graphite,the sixfold rotational symmetry of the substrate results in an equivalent rotational degeneracy in the orientation of *** this study,we explored how nanoconfinement,that is,the restriction of SAMN formation to nanometersized areas,known as nanocorrals,could impact and potentially alleviate the orientational degeneracy of SAMNs,with emphasis on the influence of molecule symmetry,size,and intermolecular *** this end,we investigated the orientation distribution of n-alkanes and functionalized alkanes within nanocorrals,which were fabricated using scanning tunneling microscopy lithography(nanoshaving).We observed lifting of orientational degeneracy for long alkanes,contrary to shorter alkanes,which did not exhibit this orientation ***,functionalized alkanes with hydrogen bonding groups demonstrated preferential alignment regardless of length,highlighting the significance of stabilizing intermolecular interactions in the alignment *** study discussed the underlying principles of the molecular packing process and shed light on the complexity of molecular self-assembly in nanoconfined spaces.

关键词： self-assembly confinement condition nanocorral orientation bias scanning tunneling microscopy

Zn Dissolution-Passivation Behavior with ZnO Formation via In Situ Characterizations

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Energy & Environmental Materials 2024年第1期7卷 193-200页

作者： Tanyanyu Wang Masahiro kunimoto Masahiro Yanagisawa Masayuki Morita Takeshi Abe Takayuki Homma Graduate School of Advanced Science and Engineering Waseda University1-104 TotsukamachiShinjuku-kuTokyo 169-8050Japan Office of Society-Academia Collaboration for Innovation Kyoto UniversityGokashoUji 611-0011Japan Graduate School of Engineering Kyoto UniversityKyoto daigaku-katsuraNishikyo-kuKyoto 615-8510Japan

In this study,ZnO formation during the dissolution-passivation process of Zn anodes is observed via in situ Raman and optical *** Zn passivation during galvanostatic anodization merely follows the dissolution-precipitation model,whereas that of potentiodynamic polarization exhibits different behaviors in different potential ***,the Zn electrode is gradually covered by a ZnO precipitation film and then undergoes solid-state oxidation at~255 *** starting point of solid-state oxidation is well indicated by the abrupt current drop and yellow coloration of the electrode *** the pseudo passivation,an intense current oscillation is ***,blink-like color changes between yellow and dark blue are revealed for the first time,implying that the oscillation is caused by the dynamic adsorption and desorption of OH *** as-formed ZnOs then experience a dissolution-reformation evolution,during which the crystallinity of the primary ZnO film is improved but the solid-state-formed ZnO layer becomes rich in oxygen ***,oxide densification is realized,contributing to the Zn *** study provides new insights into the Zn dissolution-passivation behavior,which is critical for the future optimization of Zn batteries.

关键词： in situ characterization Zn dissolution and passivation ZnO formation

A preliminary study on rectal dose reduction associated with hyaluronic acid implantation in brachytherapy for prostate cancer

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Asian Journal of Urology 2024年第2期11卷 286-293页

作者： Tairo Kashihara Yuka Urago Hiroyuki Okamoto Mihiro Takemori Hiroki Nakayama Shohei Mikasa Tetsu Nakaichi Kotaro Iijima Takahito Chiba Junichi kuwahara Satoshi Nakamura Weishan Chang Yoshiyuki Matsui Hiroshi Igaki Department of Radiation Oncology National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan Radiation Safety and Quality Assurance Division National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan Department of Radiological Sciences Graduate School of Human Health SciencesTokyo Metropolitan University7-2-10 Higashi-OguArakawa-kuTokyoJapan Department of Radiological Technology National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan Department of Urological Oncology National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyoJapan

Objectives: Hydrogel spacer (HS) was developed to reduce rectal toxicities caused by radiotherapy, but has been reported to cause major adverse events. Our institute has attempted to introduce a hyaluronic acid (HA) as an alternative spacer. This study aimed to compare rectal doses and geometric distributions between the HS and HA implantation in prostate ***: HS and HA were inserted in 20 and 18 patients undergoing high-dose brachytherapy, respectively. The rectum spacer volumes injected were 10 mL and 22 mL, respectively. In the treatment planning system, 13.5 Gy was administered with common catheter positions. The rectal dose indices were assessed between the spacer groups for dosimetry evaluation. Distances between the prostate and rectum and configurations of the spacers were ***: The mean doses irradiated to 0.1 and 2 mL of the rectum were 10.45 Gy and 6.71 Gy for HS, and 6.73 Gy and 4.90 Gy for HA (p<0.001). The mean minimum distances between the prostate and rectum were 1.23 cm and 1.79 cm for HS and HA, respectively (p<0.05). Geometrical configuration comparisons revealed that HA has a higher ability to expand the space than ***: The rectal dose reduction ability of HA is significantly greater than that of HS, suggesting its potential as a new spacer.

关键词： Brachytherapy Hyaluronicacid Hydrogel Prostaticneoplasm Radiotherapy