The power industry is rapidly changing as demand for eco-friendly and stable power supply increases along with global greenhouse gas emission regulations. Small-capacity renewable power sources ...represented by photovoltaics and wind are continuously increasing as a form of microgrid to supply electric power to a community or island. As a result, microgrids based on renewable resources have come into wide usage around small areas or islands in Korea. In particular, the microgrid development policy of Korea is focused on electric power quality, as well as expansion in renewable energy supply for reducing greenhouse gas emissions. From 2009, the government began to develop independent carbon-free microgrids with photovoltaic and wind powers instead of traditional power diesel generators for small islands. The goal of this paper is to investigate a feasible economic microgrid topology for implementing the carbon-free island (CFI) under an acceptable level of reliability. First, we derive three scenarios of power systems including photovoltaics, wind, battery, and fuel cells. Next, we assess economic feasibility on top of the power supply reliability of the scenarios. Then, we perform a sensitivity test to suggest economic conditions for achieving the CFI goals. Finally, we present carbon-free-based microgrid models considering the CFI policy of Korea.
Laser-induced graphene (LIG) has been extensively researched due to its facile fabrication on various carbon-containing substrates using simple laser scribing. In recent years, advancements have ...enabled the production of LIG on environmentally friendly substrates, opening new possibilities for designing sustainable electronics that minimize adverse environmental effects. This paper provides an overview of the latest advancements in manufacturing technologies for LIG on eco-friendly substrates, such as paper, wood, lignin biomass, cloth, food, and biocompatible parylene-C. Furthermore, a comparative analysis is conducted between LIG generated on eco-friendly substrates and graphene patterns printed using commercially available graphene ink. This analysis emphasizes the potential efficacy of LIG as an efficient manufacturing technique for producing conductive graphene patterns. The review also outlines the remaining challenges requiring attention to advance these manufacturing processes and outlooks future opportunities, which can serve as a valuable guide for both novice researchers unfamiliar with LIG and experienced researchers aiming to utilize eco-friendly substrates in their study.
We developed a multiscale model that integrates density functional theory (DFT), molecular dynamics (MD), and the finite difference method (FDM) to reflect the heterogeneous spatial distribution of ...the material ingredients on sub-10 nm photoresist (PR) pattern fabrication using extreme ultraviolet lithography (EUVL). It allowed the exploration of phototriggered chemical reactions at the molecular level, including photoacid generator (PAG) dissociation, acid diffusion-coupled deprotection, and solubility switching of individual polymer chains. To quantify the progress of the deprotection, a protection ratio of each pendant group was tracked to distinguish the dissoluble PR chains from the developer as the process time elapsed. Deprotection was shown to preferentially occur in the pendant group adjacent to the acid molecule (<0.74 nm), which determined the chemical gradient and solubility switching trend of the PR chains. Based on the full description of the phototriggered chemical reaction, the morphology of the PR line pattern was predicted after wiping out the dissoluble chains. We particularly examined the PAG loading effect (5.68–30.12 wt %) on the line edge roughness (LER) of the PR pattern and predicted the LER inversion phenomenon at the critical threshold PAG concentration, which qualitatively agreed with the experimental observations. Such a LER trend due to PAG loading was explained by the reciprocal interaction between the homogeneous packing of the acid from the dissoluble PR chains and the acid clustering behavior. The variation of the homogeneity of the deprotection in each pendant group was verified as a function of PAG concentration, which rationalized the existence of the reciprocal interaction.
In extreme ultraviolet lithography (EUVL), a photoacid generator (PAG) blended photoresist (PR) is used to transfer the blueprint from the mask to the wafer. The photoacids are predominantly ...activated by photo-triggered secondary electron attachment in EUVL, which is distinct from the direct electron excitation of PAG in conventional deep ultraviolet resists. However, uncontrolled acid dispersion causes excessive deprotection and serious damage to the residual pattern. A quencher base compound was introduced in the PR to confine the acid diffusion, but the molecular level description of the acid ↔ quencher interaction and the resulting influence on the pattern image remains elusive. We examine the quencher effect that neutralizes the acid and impedes the deprotection in the masked region, leading to the enhancement of the line edge roughness (LER) of the pattern. In addition, we investigated the loading effect of the quencher and predicted the optimal concentration of the quencher for the best LER, consistent with experimental reports. The LER optimum along the quencher concentration is interpreted by the reciprocal relationship between the acid-blocking effect at the line edge of the pattern (positive) and the acid trapping behavior in the exposure domain (negative). The variations in the deprotection homogeneity clearly demonstrate the negative impact of the acid trap phenomenon on the chemical reaction according to the quencher's loading. In multiscale modeling, PAG dissociation energy curve calculated from density functional theory (DFT) is applied to molecular dynamics (MD) simulation to reproduce the indirect photochemical activation in EUVL. The sequential multiscale framework (DFT-MD-finite difference method) also reproduces acid/base diffusion, neutralization, deprotection kinetics, and pattern morphology in EUV resist at the molecular level.
Impact of acid-base neutralization in EUV lithography was investigated using our newly developed multi-scale framework (DFT-MD-FDM).
Aerosol jet printing of electronic devices is increasingly attracting interest in recent years. However, low capability and high resistance are still limitations of the printed electronic devices. In ...this paper, we introduce a novel post-treatment method to achieve a high-performance electric circuit. The electric circuit was printed with aerosol jet printing method on an ULTEM substrate. The ULTEM substrate was fabricated by the Fused Deposition Modelling method. After post-treatment, the electrical resistance of the printed electric circuit was changed from 236 mΩ to 47 mΩ and the electric property was enhanced. It was found that the reduction of electric resistance was caused by surface property changes. Different surface analysis methods including scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS) were used to understand the effectiveness of the proposed method. The results showed that the microsurface structure remained the same original structure before and after treatment. It was found that the surface carbon concentration was significantly increased after treatment. Detailed analysis showed that the C-C bond increased obviously after treatment. The change of electrical resistance was found to be limited to the material's surface. After polishing, the circuit resistance was changed back to its original value. As the electric circuit is the basic element of electric devices, the proposed method enables the fabrication of high performance devices such as capacitors, strain gauge, and other sensors, which has potential applications in many areas such as industrial, aerospace, and military usage.
Antimicrobial resistance and multidrug resistance are slower-moving pandemics than the fast-spreading coronavirus disease 2019; however, they have potential to cause a much greater threat to global ...health. Here, we report a clustered regularly interspaced short palindromic repeats (CRISPR)-mediated surface-enhanced Raman scattering (SERS) assay for multidrug-resistant (MDR) bacteria. This assay was developed via a synergistic combination of the specific gene-recognition ability of the CRISPR system, superb sensitivity of SERS, and simple separation property of magnetic nanoparticles. This assay detects three multidrug-resistant (MDR) bacteria, species Staphylococcus aureus, Acinetobacter baumannii, and Klebsiella pneumoniae, without purification or gene amplification steps. Furthermore, MDR A. baumannii-infected mice were successfully diagnosed using the assay. Finally, we demonstrate the on-site capture and detection of MDR bacteria through a combination of the three-dimensional nanopillar array swab and CRISPR-mediated SERS assay. This method may prove effective for the accurate diagnosis of MDR bacterial pathogens, thus preventing severe infection by ensuring appropriate antibiotic treatment.
Energy‐storing functional photovoltaics, which can simultaneously harvest and store solar energy, are proposed as promising next‐generation multifunction energy systems. For the extension of ...conventional organic photovoltaics (OPVs), electrochromic supercapacitors (ECSs) are monolithically integrated with semitransparent (ST) quaternary blend‐based OPVs (ST Q‐OPVs) to achieve compact, energy‐efficient storage with great aesthetic appeal. In particular, ST Q‐OPVs with low‐power‐consumption ECSs allow full operation, even under low‐intensity irradiance, including artificial indoor light circumstances, and thereby exhibit potential for all‐day operating energy suppliers. The prepared ST energy‐storing functional photovoltaics also serve as a backup power source for external electronic equipment (e.g., light‐emitting diodes, and sensor nodes for Internet of Things) by consuming charged power. In addition to features that include unrestricted operation under any circumstances, color tunability, feasibility of designs with various shapes, rapid charging/discharging, and real‐time indication of stored energy levels, ST energy‐storing functional photovoltaics could potentially be applied in electronic devices such as advanced smart windows or portable smart electronics.
Semitransparent energy‐storing functional photovoltaics are developed by integrating quaternary blends‐based organic photovoltaics and electrochromic supercapacitor in a monolithic structure. Highly efficient operation under versatile irradiation circumstances including outdoor sun and ambient artificial indoor lighting and feasibility of any designed shape, size, and color can extend potentials for practical applications.
Alzheimer's disease (AD), one of the leading senile disorders in the world, causes severe memory loss and cognitive impairment. To date, there is no clear cure for AD. However, early diagnosis and ...monitoring can help mitigate the effects of this disease. In this study, we reported a platform for diagnosing early-stage AD using microRNAs (miRNAs) in the blood as biomarkers. First, we selected an appropriate target miRNA (miR-574-5p) using AD model mice (4-month-old 5XFAD mice) and developed a hydrogel-based sensor that enabled high-sensitivity detection of the target miRNA. This hydrogel contained catalytic hairpin assembly (CHA) reaction-based probes, leading to fluorescence signal amplification without enzymes and temperature changes, at room temperature. This sensor exhibited high sensitivity and selectivity, as evidenced by its picomolar-level detection limit (limit of detection: 1.29 pM). Additionally, this sensor was evaluated using the plasma of AD patients and non-AD control to validate its clinical applicability. Finally, to use this sensor as a point-of-care-testing (POCT) diagnostic system, a portable fluorometer was developed and verified for feasibility of application.
Metastasis attributed to approximately 90% of cancer-related deaths; hence, the detection of metastatic tumor–derived components in the blood assists in determining cancer recurrence and patient ...survival. Microfluidic–based sensors facilitate analysis of small fluid volumes and represent an accurate, rapid, and user-friendly method of field diagnoses. In this study, we have developed a microfluidic chip-based exosomal mRNA sensor (exoNA-sensing chip) for the one-step detection of exosomal ERBB2 in the blood by integrating a microfluidic chip and 3D-nanostructured hydrogels. The exoNA-sensing chip is a vacuum-driven power-free microfluidic chip that can accurately control the flow of trace fluids (<100 μL). The sensing part of the exoNA-sensing chip includes 3D-nanostructured hydrogels capable of detecting ERBB2 and a reference gene by amplifying a fluorescent signal via an enzyme-free catalytic hairpin assembly reaction at room temperature. This hydrogel offers a detection limit of 58.3 fM with good selectivity for target sequences. The performance of the exoNA-sensing chip was evaluated by testing in vitro and in vivo samples and was proven to be effective for cancer diagnosis and liquid biopsies.
•A chip capable of one-step detection of tumor-derived exosomal mRNA was developed.•3D nanostructure in the chip enables highly sensitive detection of exosomal mRNA.•ERBB2 expression levels were normalized by GAPDH on a single chip.•This system is applicable in various fields of liquid biopsy-based cancer diagnosis.
The eye is an extension of the central nervous system (CNS) and contains aqueous humor (AH), which is a fluid rich in biomolecules secreted from intraocular tissues; thus, this organ allows for ...non-invasive visualization of early changes in CNS disorders. There is a growing interest in developing implantable devices, such as intraocular-lens (IOL), for specific medical uses, including intraocular monitoring. We describe a novel IOL-sensing system for detecting AH biomarkers via biocompatible enzyme-activatable fluorogenic hydrogel sensors. Matrix-metalloproteinase-9, a biomarker of degenerative CNS and eye disorders, was selected as a target. A peptide-probe-incorporated fluorogenic IOL (FIOL) was developed using diacrylamide-group-modified poly(ethyleneglycol) (PEGDAAm) biocompatible hydrogels, adjusting the hydrogel mesh size to allow selective penetration of the target while blocking non-targets, using label-free detection with semi-permanently implantable sensors, and demonstrating the clinical feasibility of FIOL through in vivo testing. This novel FIOL-based sensing system represents a promising approach for liquid biopsy of intraocular fluids.
•The eye allows for early, non-invasive visualization of CNS disorders.•Implantable devices (intraocular-lens) are suitable for intraocular monitoring.•We detected AH biomarkers using enzyme-activatable fluorogenic hydrogel sensors.•FIOL was developed using PEGDAAm biocompatible hydrogels.•We proved the feasibility of FIOL-based sensing system for ocular liquid biopsy.
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