Publications by authors named "Joonho Bae"

The advent of two-dimensional (2D) materials and their capacity to form van der Waals (vdW) heterostructures has revolutionized numerous scientific fields, including electronics, optoelectronics, and energy storage. This paper presents a comprehensive investigation of bandgap engineering and band structure prediction in 2D vdW heterostructures utilizing density functional theory (DFT). By combining various 2D materials, such as graphene, hexagonal boron nitride (h-BN), transition metal dichalcogenides, and blue phosphorus, these heterostructures exhibit tailored properties that surpass those of individual components.

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In recent years, hierarchically porous polymer membranes (HPPMs) have emerged as promising materials for a wide range of applications, including filtration, separation, and energy storage. These membranes are distinguished by their multiscale porous structures, comprising macro-, meso-, and micropores. The multiscale structure enables optimizing the fluid dynamics and maximizing the surface areas, thereby improving the membrane performance.

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Owing to their high sensitivity across a wide stress range, mechanical reliability, and rapid response time, flexible polymer foam piezoresistive sensors have been extensively used in various fields. The reliable application of these sensors under harsh environments, however, is severely limited by structural devastation and poor interfacial bonding between polymers and conductive nanoparticles. To address the above issues, robust MXene/CNT nanocoatings on the foam surface, where the chemical assembly of MXene nanosheets and the physical anchoring of CNTs lead to strong interfacial bonding, are designed and described, which endows foams with structural reliability and unexpected multi-functionalities without compromising their instinct properties.

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In this work, we designed a novel polyvinylidene fluoride (PVDF)@DNA solid polymer electrolyte, wherein DNA, as a plasticizer-like additive, reduced the crystallinity of the solid polymer electrolyte and improved its ionic conductivity. At the same time, due to its Lewis acid effect, DNA promotes the dissociation of lithium salts when interacting with lithium salt anions and can also fix the anions, creating more free lithium ions in the electrolyte and thus improving its ionic conductivity. However, owing to hydrogen bonding between DNA and PVDF, excess DNA occupies the lone pairs of electrons of the fluorine atoms on the PVDF molecular chains, affecting the conduction of lithium ions and the conductivity of the solid electrolyte.

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Intumescent fire-retardant coatings, which feature thinner layers and good decorative effects while significantly reducing heat transfer and air dispersion capabilities, are highly attractive for fire safety applications due to their effective prevention of material combustion and protection of materials. Particularly, the worldwide demand for improved environmental protection requirements has given rise to the production of waterborne intumescent fire-retardant polymer composite coatings, which are comparable to or provide more advantages than solvent-based intumescent fire-retardant polymer composite coatings in terms of low cost, reduced odor, and minimal environmental and health hazards. However, there is still a lack of a comprehensive and in-depth overview of waterborne intumescent fire-retardant polymer composite coatings.

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Recent years have witnessed the explosive development of highly sensitive smart sensors based on conductive polymer foam materials. However, the design and development of multifunctional polymeric foam composites as smart sensors applied in complex solvent and oil environments remain a critical challenge. Herein, we design and synthesize vinyl-terminated polytrifluoropropylmethylsiloxane through anionic ring-opening polymerization to fabricate fluorosilicone rubber foam (FSiRF) materials with nanoscale wrinkled surfaces and reactive Si-H groups via a green and rapid chemical foaming strategy.

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Lithium-selenium batteries have emerged as a promising alternative to lithium-sulfur batteries due to their high electrical conductivity and comparable volume capacity. However, challenges such as the shuttle effect of polyselenides and high-volume fluctuations hinder their practical implementation. To address these issues, we propose synthesizing Fe-CNT/TiO catalyst through high-temperature sintering of an amalgamated nanoarchitecture of carbon nanotubes decorated metal-organic framework (MOF) and MXene, optimized for efficient selenium hosting, leveraging the distinctive physicochemical properties.

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Selenium-based electrodes have garnered attention for their high electrical conductivity, compatibility with carbonate electrolytes, and volumetric capacity comparable to sulfur electrodes. However, real-time application is hindered by rapid capacity deterioration from the "shuttle effect" of polyselenides and volume fluctuations. To address these challenges, a hybrid Se@ZIF-67/Mo-MXene-derived (Se@Co-NC/MoC) nanoarchitecture is developed via an economically viable in situ electrostatic self-assembly of ZIF-67 and MoC nanosheets.

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A facile method for synthesizing carbon-coated lithium iron phosphate (LiFePO, LFP) and an LFP-based multidimensional nanocarbon composite to enhance the electrochemical performance of lithium-ion batteries is presented herein. Three types of cathode materials are prepared: carbon-coated LFP (LC), carbon-coated LFP with carbon nanotubes (LC@C), and carbon-coated LFP with carbon nanotubes/graphene quantum dots (LC@CG). The electrochemical performances of the LC-nanocarbon composites are compared, and both LC@C and LC@CG show improved electrochemical performance than LC.

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Graphene quantum dots (GQDs) with a band gap have been widely applied in many fields owing to their unique optical properties. To better utilize the optical advantages of GQDs, it is important to understand their optical characteristics. Our study demonstrates the optical properties and carrier behaviors of synthesized graphene oxide quantum dot (GOQD) and reduced graphene oxide quantum dot (rGOQD) pellets via Terahertz time-domain spectroscopy (THz-TDS).

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Lithium-ion capacitors (LICs) are next-generation electrochemical storage devices that combine the benefits of both supercapacitors and lithium-ion batteries. Silicon materials have attracted attention for the development of high-performance LICs owing to their high theoretical capacity and low delithiation potential (∼0.5 V versus Li/Li).

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Nanomaterials and nanotechnology have played central roles in the realization of high-efficiency and next-generation energy storage devices [...

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The challenge of safety problems in lithium batteries caused by conventional electrolytes at high temperatures is addressed in this study. A novel solid electrolyte (HKUST-1@IL-Li) was fabricated by immobilizing ionic liquid ([EMIM][TFSI]) in the nanopores of a HKUST-1 metal-organic framework. 3D angstrom-level ionic channels of the metal-organic framework (MOF) host were used to restrict electrolyte anions and acted as "highways" for fast Li transport.

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Atomic force microscopy has a tremendous number of applications in a wide variety of fields, particularly in the semiconductor area for the 3D-stacked device. Imaging three-dimensional (3D) structures with blind features has progressively become a critical technique. Recently, a 3D-atomic force microscopy (AFM) technique has been proposed to image 3D features, especially those having sharp apices, like silicon pillars.

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Reduced equivalent series resistance (ESR) is necessary, particularly at a high current density, for high performance supercapacitors, and the interface resistance between the current collector and electrode material is one of the main components of ESR. In this report, we have optimized chemical vapor deposition-grown graphene (CVD-G) on a current collector (Ni-foil) using reduced graphene oxide as an active electrode material to fabricate an electric double layer capacitor with reduced ESR. The CVD-G was grown at different cooling rates-20 °C min, 40 °C min and 100 °C min-to determine the optimum conditions.

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In this work, the morphology of ZnO nanostructures is engineered to demonstrate enhanced supercapacitor characteristics of ZnO nanocones (NCs) compared to ZnO nanowires (NWs). ZnO NCs are obtained by chemically etching ZnO NWs. Electrochemical characteristics of ZnO NCs and NWs are extensively investigated to demonstrate morphology dependent capacitive performance of one dimensional ZnO nanostructures.

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Purpose: The purpose of this study was to improve methods of jet injection using a mouse model. We investigated the mechanism of action, efficacy, and safety of the pneumatic device using injection of hyaluronic acid (HA) solution into a mouse model.

Methods: We evaluated the efficacy and safety of an INNOJECTOR™ pneumatic device that pneumatically accelerates a jet of HA solution under high pressure into the dermis of mouse skin.

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Objective: We investigated whether leflunomide can be delivered topically and metabolized into teriflunomide through the skin, and evaluated the therapeutic effect of topical leflunomide.

Methods: Permeation of leflunomide across and formation of its active metabolite within the skin was examined ex vivo. Deposition of teriflunomide in micropig knee joints after applying topical and transdermal patches containing leflunomide was investigated by determining the plasma and joint tissue concentrations.

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We prepared an injectable depot system for the long-term delivery of alendronate using a solid/water/oil/water multiple emulsion technique with poly(lactic-co-glycolic acid) as a carrier. The microparticles were spherical with smooth surfaces, ranging from 20 to 70 μm in size. The microspheres (ALD-HA-RG504H-MC70) were optimally prepared by introducing a viscous material (hyaluronic acid) and a co-solvent system in the inner aqueous and oil phases, respectively, and showed a significantly increased drug encapsulation efficacy (>70%); the initial burst release was <10% after 1 day.

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Defibrillation is no longer universally recommended as initial intervention for the reversal of ventricular fibrillation (VF) after a prolonged and untreated cardiac arrest. We sought to examine this issue in an animal model where a prolonged untreated VF was induced. The aim of this study was to investigate the potential mechanism of the detrimental effect of defibrillation prior to cardiopulmonary resuscitation (CPR) in prolonged cardiac arrest model.

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Objectives: The objectives of this study were to compare the variations of bone density in the midfacial bones as measured by computed tomography (CT) scans between the osteoporosis and control groups and to evaluate the regions that facial trauma and iatrogenic problem often occur in the midface.

Methods: The 96 patients who underwent both osteomeatal unit CT scans and dual-energy x-ray absorptiometry at our hospital were included in this study retrospectively. Seven skeletal regions were chosen for evaluation: group A (orbital floor, nasal bone), group B (zygomaticomaxillary suture, zygomatic arch, zygomaticofrontal suture), and group C (anterior wall of the maxillary sinus, maxillary process).

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Meningioma's account for around 15% of all primary brain tumors with some 10% of meningiomas arising in the posterior fossa. In rare cases, a meningioma can form around the endolymphatic sac. When formed in the posterior fossa, meningioma tumors can produce vague, non-specific vertiginous symptoms.

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This study was designed to develop a skin permeable recombinant low-molecular-weight protamine (LMWP) conjugated epidermal growth factor (EGF) (rLMWP-EGF) by linking a highly positive charged LMWP to the N-terminal of EGF through genetic recombination. We evaluated its biological activity, skin permeability, and wound healing efficacy in vivo. The cDNA for rLMWP-EGF was prepared by serial polymerase chain reaction for encoding amino acids of LMWP to the vector for EGF.

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Purpose: To evaluate the ability of a novel radiofrequency (RF) microporation technology based on ablation of the skin barrier to enhance topical delivery of active ingredients

Methods: The influence of RF fluence and the molecular size of the absorbent on the permeation enhancement was confirmed by in vitro skin permeation study using Franz diffusion cells. The improved skin rejuvenation effects, such as depigmentation and anti-wrinkle effects, by enhanced topical delivery of α-bisabolol and epidermal growth factor (EGF) through the RF microchannels were investigated in photo-damaged skin.

Results: The cumulative amounts of active ingredients through the RF microporated skin were significantly increased.

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