88 research outputs found
PDMS와 parylene C의 선택적 접착 기반 소프트하고 유연한 3차원 생체 이식 전자장치
No full textbio-integrated electronics, soft and flexible electronics, 3-dimensional structure, neural interface, crack-free electrodes, cuff electrodesNDoctordCollectio
Opportunities and Challenges in Twisted Bilayer Graphene: A Review
No full textTwo-dimensional (2D) materials exhibit enhanced physical, chemical, electronic, and optical properties when compared to those of bulk materials. Graphene demands significant attention due to its superior physical and electronic characteristics among different types of 2D materials. The bilayer graphene is fabricated by the stacking of the two monolayers of graphene. The twisted bilayer graphene (tBLG) superlattice is formed when these layers are twisted at a small angle. The presence of disorders and interlayer interactions in tBLG enhances several characteristics, including the optical and electrical properties. The studies on twisted bilayer graphene have been exciting and challenging thus far, especially after superconductivity was reported in tBLG at the magic angle. This article reviews the current progress in the fabrication techniques of twisted bilayer graphene and its twisting angle-dependent properties. © 2020, The Author(s).1
Biomolecular Imaging of Regeneration of Zebrafish Caudal Fins Using High Spatial Resolution Ambient Mass Spectrometry
No full textWe
observed the molecular distribution changes that occurred during
the regeneration of fresh zebrafish caudal fins using the recently
developed ambient high-resolution mass spectrometry (MS) imaging technique
of atmospheric pressure–nanoparticle and plasma-assisted laser
desorption ionization (AP-nanoPALDI). AP-nanoPALDI analyses of fresh
zebrafish caudal fins revealed that the small molecules, including
neurotransmitters, amino acids, lipids, and metabolites of the regenerated
area, were more evenly distributed throughout the bony rays and inter-ray
mesenchymal tissues compared to the original area in the early stage.
Zebrafish caudal fins of less than 200 μm thickness can be very
useful for tissue regeneration studies using ambient MS imaging by
providing sufficient biomolecular information at the molecular level
for wound-healing studies. AP-nanoPALDI imaging was compared with
a complementary MS imaging tool, surface sensitive time-of-flight
secondary ion MS (ToF-SIMS)
Graphene-mediated enhanced Raman scattering and coherent light lasing from CsPbI3 perovskite nanorods
No full textGraphene-enhanced Raman scattering has been studied as an optical technique related to the selective electron transfer from graphene to the valence band of the contacted molecule, inducing a pileup of electrons within the conduction band and a “photogating effect” for subsequently illuminated light. Herein, we studied the Raman spectroscopy of CsPbI3 nanorods sandwiched between two layers of graphene, revealing that weak coherent lasing also occurs. The photoluminescence intensity of α-phase CsPbI3 nanorods drastically decreased with increasing graphene coverage, particularly on the top, leading to Raman modes at the first (~241 and ~312 cm−1) and second (~640 cm−1) overtones of polymeric iodides, as well as at ~3492 cm−1. First-principle calculations reveal that the ~3492-cm−1 mode originates from the stimulated coherent light emissions of the highly populated electrons accumulated in the CsPbI3 conduction band, which form because of the electronic resonance induced in the Pb and I degenerate states. © 20201
Probing the Upper Band Gap of Atomic Rhenium Disulfide Layers
No full textHere, we investigate the ultrafast carrier dynamics and electronic states of exfoliated ReS2 films using time-resolved second harmonic generation (TSHG) microscopy and density functional theory (DFT) calculations. The second harmonic generation (SHG) of layers with various thicknesses is probed using a 1.19-eV beam. Up to ~13 nm, a gradual increment is observed, followed by a decrease caused by bulk interferometric light absorption. The addition of a pump pulse tuned to the exciton band gap (1.57 eV) creates a decay-to-rise TSHG profile as a function of the probe delay. The power and thickness dependencies indicate that the electron–hole recombination is mediated by defects and surfaces. The two photon absorptions of 2.38 eV in the excited state that are induced by pumping from 1.57 to 1.72 eV are restricted because these transitions highly correlate with the forbidden d–d intrasubshell orbital transitions. However, the combined usage of a frequency-doubled pump (2.38 eV) with wavelength-variant SHG probes (2.60–2.82 eV) allows us to vividly monitor the variations in TSHG profiles from decay-to-rise to rise-to-decay, which imply the existence of an additional electron absorption state (s-orbital) at an approximate distance of 5.05 eV from the highest occupied molecular orbital states. This observation was critically examined by considering the allowance of each electronic transition and a small upper band gap (~0.5 eV) using modified DFT calculations. © 2018, The Author(s).1
Designing Expressive Movements for Non-Anthropomorphic Hotel Restaurant Service Robots
No full textThe hospitality industry, struggling with significant staff shortages, has increasingly turned to service robots as a solution. However, the prevalent service robot’s design with anthropomorphic appearance is considered inharmonious with the fine-dining restaurant ambiance and may harm the guests’ perception of the service. An alternative approach is exemplified by Rober, which adopts a design resembling a traditional cart. The non-anthropomorphic design offers flexibility, economic efficiency, and enhanced acceptability in hospitality settings. However, it also raises challenges in expressing intentions that are typically conveyed through human non-verbal cues. Consequently, the movement quality of service robots becomes a critical area of design to facilitate nuanced human-robot interaction (HRI) in hotel restaurant contexts.The research focused on two main questions: how to design robot movement to facilitate essential interaction and collaboration qualities during dining experiences, and how to craft these movements using a dramaturgic performative approach. The project employed methodologies like speculative enactment and Extended Reality (XR) experiments to explore and evaluate robot movements. These methods allowed for creative ideation and assessments of the robot’s movements in simulated dining scenarios.The project’s findings revealed that specific robot movements, including refined presence, prompted actions, and engaging addresses, significantly enhance the experience of guests, staff, and managers of the hotel restaurant. The robot’s role was envisioned as an ‘Ensemblist,’ a term encapsulating its function as an integral yet unobtrusive participant in the fine dining scene. This role demands the robot be ‘response-able,’ adapting to the fine dining rhythm. Furthermore, the project’s performative approach illuminated methods to design the robot’s movement as expressively meaningful and contextually appropriate. Methodological reflections revealed the effectiveness of speculative enactment and XR experiments in capturing the complexities of human-robot interactions, though suggesting future improvements in prototype fidelity, participant diversity, and advanced data treatment.This project contributes to the field of HRI in hospitality, bridging theoretical concepts with practical applications. It lays the groundwork for future research in service robot design, emphasizing the need for nuanced interaction designs that resonate with human users in the hospitality sector.Design for Interactio
Combinatory actions of CP29 phosphorylation by STN7 and stability regulate leaf age-dependent disassembly of photosynthetic complexes
No full text© 2020, The Author(s). A predominant physiological change that occurs during leaf senescence is a decrease in photosynthetic
efciency. An optimal organization of photosynthesis complexes in plant leaves is critical for efcient
photosynthesis. However, molecular mechanisms for regulating photosynthesis complexes during leaf
senescence remain largely unknown. Here we tracked photosynthesis complexes alterations during
leaf senescence in Arabidopsis thaliana. Grana stack is signifcantly thickened and photosynthesis
complexes were disassembled in senescing leaves. Defects in STN7 and CP29 led to an altered
chloroplast ultrastructure and a malformation of photosynthesis complex organization in stroma
lamella. Both CP29 phosphorylation by STN7 and CP29 fragmentation are highly associated with the
photosynthesis complex disassembly. In turn, CP29 functions as a molecular glue to facilitate protein
complex formation leading phosphorylation cascade and to maintain photosynthetic efciency during
leaf senescence. These data suggest a novel molecular mechanism to modulate leaf senescence via
CP29 phosphorylation and fragmentation, serving as an efcient strategy to control photosynthesis
complexes.11Nsciescopu
Wavefront-modulated four-wave mixing interferometry with silicon checkerboard gratings
No full textNonlinear optical FWM generation was studied using a wavefront-modulated beam to understand how emissions adapt under additional interference. Size-dependent circular π-phase-modulated masks were applied to create stepwise, z-directionally elongated, bottleneck-shaped FWM foci as schematic interference conditions. The polarizing FWM features varied dramatically as the circular mask size approached 0.35 times the beam barrel, resulting in the convergence of two inherently paired emissions without significant contrast at the edges. The results were reproduced through kernel-type filtering using two-dimensional nonlinear spatial filters with computationally efficient focal field calculations. © 2014, Springer-Verlag Berlin Heidelberg
TRANSFORMATION OF 2D PLANES INTO 3D SOFT STRUCTURES WITH ELECTRICAL FUNCTIONS
No full text3-dimensional (3D) structures composed of flexible and soft materials have been in demand for bio-integrated devices. However, the fabrication of 3D structures using micro electro mechanical systems (MEMS) techniques has limitations in terms of commonly used inorganic materials and the microscale of resulted structures. Here, we developed a novel technique to selectively bond polydimethylsiloxane (PDMS) and parylene C by plasma treatment, with which 2D structures fabricated using conventional MEMS techniques are transformed into 3D structures by the inflation of selectively non-bonded patterns. We demonstrated various soft and flexible 3D devices with embedded electrical functions for biomedical applications. © 2021 IEEE
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