Publications by authors named "Jun Oh Kim"

Magnetic soft actuators allow high-frequency shape reconfiguration of the micropillar array by rapid rotation of an external magnetic field; however, viscoelastic soft actuators cannot instantaneously reach an equilibrium deformation state to minimize the magnetic moment at a given short time scale, resulting in a significant reduction of the strain amplitude. Herein, we report high-frequency magnetic oscillation of a micropillar array without significant reduction in frequency or strain amplitude by programming the magnetization direction of hard magnetic microparticles embedded in a soft elastomer. Various oscillatory motions, including bending, twisting, and torsion under time-varying external magnetic fields, are demonstrated via programming the magnetization of anisotropic micropillars.

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Von Neumann architecture-based computing, while widely successful in personal computers and embedded systems, faces inherent challenges including the von Neumann bottleneck, particularly amidst the ongoing surge of data-intensive tasks. Neuromorphic computing, designed to integrate arithmetic, logic, and memory operations, has emerged as a promising solution for improving energy efficiency and performance. This approach requires the construction of an artificial synaptic device that can simultaneously perform signal processing, learning, and memory operations.

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Article Synopsis
  • Hardware security is becoming increasingly important due to the rise of connected devices in consumer and medical fields, with physical unclonable functions (PUFs) being a potential solution for secure cryptographic operations.
  • The study introduces an enhanced electrical PUF that utilizes two-dimensional (2D) transition metal dichalcogenides (TMDCs) in field-effect transistors (FETs) to improve both entropy and parameter variability, addressing current vulnerabilities.
  • Performance analyses of these novel PUFs show promising results in terms of characteristics like uniqueness, randomness, and reproducibility, making them suitable for immediate deployment in various hardware security applications.
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Inverse-vulcanized polymeric sulfur has received considerable attention for application in waste-based infrared (IR) polarizers with high polarization sensitivities, owing to its high transmittance in the IR region and thermal processability. However, there have been few reports on highly sensitive polymeric sulfur-based polarizers by replication of pre-simulated dimensions to achieve a high transmission of the transverse magnetic field (T ) and extinction ratio (ER). Herein, a 400-nanometer-pitch mid-wavelength infrared bilayer linear polarizer with self-aligned metal gratings is introduced on polymeric sulfur gratings integrated with a spacer layer (SM-polarizer).

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Emergence agitation (EA) is one of the main concerns in the field of pediatric anesthesia using sevoflurane. We investigated the effects of remifentanil and fentanyl on the incidence of EA in pediatric patients undergoing strabismus surgery. Ninety children were randomly allocated into two groups and received either remifentanil (group R: intraoperatively remifentanil 0.

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In the case of complete surgical resection of locally aggressive thyroid mass with severely compromised airways, airway management is difficult and can be considerably risky. We report a case of airway management using i-gel™ and cardiopulmonary bypass (CPB) with venoarterial extracorporeal membrane oxygenation (ECMO), which is a safe and feasible method of airway management for providing general anesthesia in a patient with a large thyroid mass.

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The algorithmic spectrometry as an alternative to traditional approaches has the potential to become the next generation of infrared (IR) spectral sensing technology, which is free of physical optical filters, and only a very small number of data are required from the IR detector. A key requirement is that the detector spectral responses must be engineered to create an optimal basis that efficiently synthesizes spectral information. Light manipulation through metal perforated with a two-dimensional square array of subwavelength holes provides remarkable opportunities to harness the detector response in a way that is incorporated into the detector.

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Background: The incidence of skin cancer, which is primarily caused by exposure to ultraviolet radiation, has steadily increased in recent years. The authors of the present study sought to investigate changes in the epidemiology of skin cancer by conducting a retrospective review of patients diagnosed with skin cancer who received related care at a single medical institution.
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Background: Defects of the nasal ala and tip have a complex three-dimensional structure that makes them challenging to reconstruct. Many reconstructive options have been described for nasal ala and tip defects, ranging from primary closure to local flaps and skin grafts. However, it is difficult to determine which method will yield the best cosmetic results in each individual case.

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Background: Skin defects of head and neck need reconstruction using various local flaps. In some cases, surgeons should consider skin graft for large skin defect. It is important to heal skin graft and donor sites.

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We present experimental and theoretical investigations on the polarization properties of a single- and a double-layer gold (Au) grating, serving as a wire grid polarizer. Two layers of Au gratings form a cavity that effectively modulates the transmission and reflection of linearly polarized light. Theoretical calculations based on a transfer matrix method reveals that the double-layer Au grating structure creates an optical cavity exhibiting Fabry-Perot (FP) resonance modes.

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This study revealed S fluorescence from deprotonated meso-pentafluorophenyl-substituted Möbius aromatic [32]heptaphyrin(1.1.1.

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To understand how disorder within conjugated polymer aggregates influences the polaron generation process, we investigated poly(3-hexylthiophene) (P3HT) and a congeneric random copolymer incorporating 33 mol % substituent-free thiophene units (RP33). Steady-state absorption and fluorescence spectra showed that increasing the intrachain torsional disorder in aggregates increases the energy and breadth of the density of states (DOS). By extracting polaron dynamics in the transient absorption spectra, we found that an activation energy barrier of 0.

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A detailed theoretical study of the optical absorption in doped self-assembled quantum dots is presented. A rigorous atomistic strain model as well as a sophisticated 20-band tight-binding model are used to ensure accurate prediction of the single particle states in these devices. We also show that for doped quantum dots, many-particle configuration interaction is also critical to accurately capture the optical transitions of the system.

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Background: Surgery for reconstruction of defects after surgery should be performed selectively and the many points must be considered. The authors conducted this study to compare the local flap and skin graft by facial location in the reconstruction after resection of facial skin cancer.

Methods: The authors performed the study in patients that had received treatment in Department of Plastic Surgery, Gyeongsang National University.

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meso-to-meso 2,5-Pyrrolylene bridged zig-zag porphyrin arrays have been synthesized via a stepwise Suzuki-Miyaura cross coupling reaction. Both the dimeric and trimeric structures of Zn porphyrin were confirmed by X-ray diffraction analysis. DFT calculations indicate that the porphyrin oligomers are all in zig-zag conformations.

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Cutaneous leiomyosarcoma is an uncommon superficial soft tissue sarcoma and mainly found in the middle aged to elderly males. It can occur in any part of the body, mostly affecting the extremities and rarely affecting the face. It grows relatively slowly, can be diagnosed by biopsy and is treated by surgical excision.

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An odontogenic cutaneous fistula is a pathological communication between the outer skin surface of the face and the oral cavity. Facial cutaneous fistula is a complication of odontogenic infection that is often misdiagnosed with skin infection. We report a rare case, which was diagnosed as basal cell carcinoma based on the biopsy of skin lesions in the patient who had been diagnosed with odontogenic cutaneous fistula.

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Tri(4-iodo-2,3,5,6-tetrachlorophenyl)methane (2) is reported as a general building block for the synthesis of various π-conjugated polychlorotriphenylmethyl (PTM) radicals. Three push-pull-type triphenylamine-substituted PTM radicals with different substitution patterns were prepared and all exhibited intense inter-valence charge-transfer bands and large two-photon absorption (TPA) cross sections. Moreover, increase of solvent polarity also resulted in improved TPA response.

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To explore stable organic diradicaloids, meso-thienylquinonoid-substituted porphyrins Pn and hexaphyrins Hn, where "n" denotes the number of thienyl units in the meso-substituents, were synthesized. P0 was identified as a closed-shell quinonoid, whereas P1 was shown to possess significant diradical character with diradical character index (y) of 0.99 and quite small singlet-triplet energy gap (ΔE ) of -0.

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Over the years, there has been increasing interest in the integration of metal hole array (MHA) with optoelectronic devices, as a result of enhanced coupling of incident light into the active layer of devices via surface plasmon polariton (SPP) resonances. However, not all incident light contributes to the SPP resonances due to significant reflection loss at the interface between incident medium and MHA. Conventional thin-film antireflection (AR) coating typically does not work well due to non-existing material satisfying the AR condition with strong dispersion of MHA's effective impedances.

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Treatment of nonaromatic N-fused [24]pentaphyrin with trichloromethylsilane in the presence of a base afforded doubly N-fused [24]pentaphyrin and its silicon complex. Addition of fluoride ion to the silicon complex led to the formation of its fluorosilicate as an unprecedented monoanionic six-coordinated Si complex of porphyrinoid. Treatment of the fluorosilicate with acid led to the recovery of the silicon complex.

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We report improvement of terahertz (THz) wave radiation for Si-based catalyst-free InAs nanowires (NWs) by simple dipping into tap water (DTW). In addition, the possibility of using InAs NWs as a cost-effective method for biomedical applications is discussed by comparison to bulk InAs. The peak-to-peak current signals (PPCSs) of InAs NWs measured from THz time-domain spectroscopy increased with increasing NW height.

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Article Synopsis
  • The study explores target detection through a plasmonic sensor array using a method called "algorithmic spectrometry," which captures high-resolution data across multiple wavelengths.
  • The research focuses on developing a full-scale infrared camera by demonstrating adaptive multispectral imagery with specially designed plasmonic filter arrays that enhance target detection.
  • The experiment successfully reconstructed spectra from various targets, including blackbody radiation and a metal ring, and tested the filters under high-temperature conditions to evaluate the detection method's effectiveness.
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Organic radicals display unique physical structures and could become next generation functional materials. However, design and synthesis of stable neutral radicals with a significant polyradical character has been an enormous challenge for chemists. In this work, we synthesized a series of stable 3,6-linked, kinetically blocked fluorenyl radical oligomers up to hexamer (FR-n, n = 1-6).

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