Abstract Nanomaterials have facilitated the development of innovative technologies in various industries. However, most research has been limited to nanoscale phenomena, and the effects of nanoscale phenomena on microscale crystal growth remain obscure. In this study, we demonstrated a straight 2H-Si microneedle with a longitudinal growth rate of 6.7 × 104 Å·s-1, which could not be explained by conventional crystal growth mechanisms, through AlN nanowires. The AlN nanowires were grown using the hydride vapor-phase epitaxy method, which induced the formation of Al membranes when NH3 supply was ceased. At this time, an elliptical Al membrane was created within 0.166 s, in accordance with the principle of Plateau–Rayleigh instability. The average spacing of the Al membrane was 4 μm, and approximately 10,000 elliptical Al membranes absorbed SiCl almost simultaneously to form a 40-mm 2H-Si microneedle within 100 min of growth time. Therefore, we realized straight 2H–Si microneedles with a growth rate of 6.7 × 104 Å·s-1. Differing from the conventional growth mechanism, this new growth method sheds light on the mechanism by which nanoscale phenomena contribute to the growth of microscale crystals.

We show that the degree of risk-sharing among heterogeneous workers is a key determinant of monetary non-neutrality in a multisector sticky-price model. In this framework, workers are employed across different sectors, earning distinct wages. The limited ability of workers to fully insure against labor income risks results in strategic complementarity in firms' price-setting decisions with respect to aggregate shocks and strategic substitutability with respect to idiosyncratic shocks. These pricing interactions lead to sluggish adjustments of the price level in response to monetary and other aggregate shocks, causing significant fluctuations in the output gap while maintaining large responses of individual prices to idiosyncratic shocks. We illustrate these results across three stylized asset market scenarios: complete markets, non-contingent bond-only markets, and financial autarky.

We propose an effective method to enhance resolution in light field (LF) three-dimensional (3D) displays using a virtual-moving liquid crystalline polymer-lenticular lens array (LCP-LLA) combined with a time-sequential polarization control scheme and rapid lateral switching of periodic focusing operations. The virtual-moving LCPLLA is custom-fabricated by stacking two LCP-LLAs with a half sub-pixel pitch offset, enabling a time-sequential virtual lateral shift of the focal plane. Additionally, we enhance the angular resolution of reconstructed 3D images by optimizing the lateral shifting configurations of the stacked LCP-LLAs in alignment with the sub-pixel arrangement of the display panel. These approaches notably minimize spatial resolution loss while improving angular resolution with a fixed panel configuration, based on the optical properties of the custom-designed virtual-moving LCP-LLA. Experimental validation demonstrates the efficacy of this method, achieving two-fold enhancement in angular resolution for 3D images with 20 viewpoints, without compromising spatial resolution.

In this study, single-walled carbon nanotube (SWCNT)/Cu nanocomposites were systematically synthesized from oxidized SWCNTs and Cu formate via photothermal heating.

We report a method that uses an additively-manufactured sacrificial mold to fabricate ceramic cellular structures that have a gyroid geometry. The mold has a complex periodic architecture, and was produced by additive manufacturing that applies fused deposition modelling, then a ceramic slurry was infiltrated into its cavity by centrifugation. This approach enables fabrication of geometrically-elaborate ceramic shapes such as gyroid by using low-cost and accessible equipment. The resulting gyroid filter had good mechanical integrity and good ability to capture gaseous cesium. The proposed method allows structural optimization of the filter, and tunable capture characteristics.

Inflammation is a protective response of the body, but excessive inflammation can exacerbate conditions such as acute lung injury and asthma. N-(p-Coumaroyl) serotonin (CS) is known to have anti-inflammatory effects. The present study aimed to explore the anti-inflammatory effects of CS on lipopolysaccharide (LPS)-induced inflammatory responses in macrophages and lung epithelial cells. Cellular inflammatory responses and associated signaling pathways were analyzed using ELISA, Western blotting and immunocytochemistry. Initial increase in cytokine (including IL-6 and TNF-α) and chemokine [including monocyte chemoattractant protein-1 (MCP-1)] levels, nitric oxide formation and inducible NO synthase expression in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, was reduced by CS pretreatment. In addition, CS blocked LPS-induced MAPK/NF-κB activation in RAW264.7 cells. CS led to heme oxygenase-1 (HO-1) upregulation in RAW264.7 cells. In PMA-stimulated A549 lung epithelial cells, the increase in IL-6, TNF-α and MCP-1 expression was also attenuated by CS. This was accompanied by decreased MAPK/NF-κB activation. Furthermore, CS elevated the expression of HO-1 in A549 cells. Collectively, the present study confirmed that CS exhibited anti-inflammatory effects in both macrophages and lung epithelial cell lines, suggesting that CS may alleviate systemic or lung inflammation.

Epitaxially regrown electrically pumped photonic crystal surface‐emitting lasers (PCSELs) emitting near 2 and 2.6 μm are designed, fabricated, and characterized. A high‐index‐contrast photonic crystal layer is incorporated into the GaSb‐based laser heterostructure by air‐hole‐retaining epitaxial regrowth. A square lattice of triangular holes is etched in the top waveguide core layer of the incomplete laser heterostructure. The nanopatterned surface is subsequently cleaned and regrown with AlGaAsSb p‐cladding material. Transmission electron microscopy studies demonstrate uniform regrowth over the nanopatterned GaSb surface. The selected regrowth regimes yield a buried 2D array of elongated air‐holes. The diode PCSELs based on moderately etched nanopatterns demonstrate band‐edge lasing near 2 μm up to room temperatures. The cascade diode PCSELs operate near 2.6 μm with minimum threshold current densities of about 500 A cm−2 achieved at 180 K. The devices generate mW level output in narrow divergence beam emitted from the window in substrate contact. The angle‐resolved electroluminescence measurements reveal a four‐sub‐band band structure with an apparent photonic bandgap corresponding to the buried high‐index‐contrast square photonic crystal layer. The PCSELs made of heterostructures supporting two modes in the vertical direction demonstrate two sets of sub‐bands showing anti‐crossing‐like interaction.

The CaF2 single crystal has notable characteristics such as a large band gap (12 eV), excellent transparency over a wide wavelength range, low refractive index and dispersion. Due to these outstanding properties, CaF2 single crystal has considered as a promising material for short-wavelength light sources in recent lithography processes. However, there is an inherent birefringence of the material at 157 nm and the resulting aberration can be compensated for through the combination of the (100) plane and the (111) plane. Therefore, it is necessary to investigate the characteristics according to the plane. In this study, we analyzed crystallinity, optical properties of commercial CaF2 single crystal wafers grown by the Czochralski method. In particular, through chemical etching under various conditions, it was confirmed that the shape of etch pits appears differently depending on the plane and the shape and array of specific etch pits affected by dislocations and defects were examined.

A new method for reducing the cost and the fabrication time of source material required for SiC crystal growth has been proposed through a heat treatment of recycled powder bulk in this study. The actual crystal growth with using a conventional powder and a recycled powder bulk source has been performed under identical growth condition and then systematically compared in terms of the crystal quality. With applying the recycled powder bulk for SiC crystal growth, similar growth results were obtained as a result grown by conventional high-purity powder source. In terms of crystal defects, slight improvement was observed when high purity recycled powder bulk source was applied.

Microencapsulation is an available and effective therapeutic option for entrapping targeted bioactive components. In this study, biomineralization-mediated separation and encapsulation of food-derived bioactive materials in organic materials were conducted, and the storage stability and effectiveness of these materials in the promotion of skin wound healing were assessed. To generate fine-textured and mechanically stable hexagonal particles, the hybrid materials were assembled using CaCO3 mineralized with an amphiphilic copolymer coupled with curcumin (CUR). The synthesized products were characterized using field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and particle size analysis. The hybrid microparticles contained 1.58 wt% of CUR, and 91% of its initial concentration was retained after storage at four different temperatures. Based on the crystallization mechanism, CUR with an amphiphilic copolymer could be the core component that provides the surface for CaCO3 crystal growth, causing independent formation of the organic–inorganic structures and preventing CUR leaching. Furthermore, the induced hybrid particles were found to promote skin wound healing by stimulating collagen synthesis without inducing cytotoxicity. To the best of our knowledge, this is the first study to demonstrate the potential use of bioactive ingredients with an amphiphilic copolymer combined with biomineralization for formulation purposes and to achieve a skin wound healing effect.

This study investigated the structural changes in oak and larch lignin -carbohydrate complexes (LCCs) during hydrothermal treatment and enzymatic hydrolysis. Hydrothermal treatment caused hemicellulose degradation (degradation rate at 170 celcius: larch 19.40%; oak, 22.26%). The LCC1 (glucan-lignin) fraction was the highest in the raw material of both biomasses. The LCC3 (xylan-lignin) and LCC2 (glucomannan-lignin) fractions were high in oak and larch, respectively; these fractions decreased as the hydrothermal treatment temperature increased (owing to hemicellulose degradation). Both biomasses had phenyl glycoside, benzyl ether (BE), and gamma-ester (Est) linkages. The BE and Est linkages decreased as the hydrothermal treatment temperature increased; the Est linkages decrease was more significantly in oak than in larch. The efficiency of enzymatic hydrolysis was higher in oak than that in larch and increased as the hydrothermal treatment temperature increased. Furthermore, enzyme adsorption on the LCC1 sensor was higher in oak than in larch. The chemical compositions and LCC linkages of the biomass were changed by the hydrothermal treatment, which affected the efficiency of enzymatic hydrolysis. Moreover, the efficiency of enzymatic hydrolysis was higher for oak than for larch because of the difference hemicellulose and cellulose contents and LCC linkages.

The modified SiC slurry for CMP process was proposed in order to obtain high-quality surface of 150 mm SiC wafer and then tried to explain the mechanism of the effect of added transition metal ion to improve polishing characteristics of SiC crystal substrate. SiC substrate with using modified slurry exhibited slightly higher MRR value and lower platen temperature than those with using commercial slurries. The addition of transition metal ion into the slurry enhanced oxidation efficiency of SiC crystal surface and improved MRR and the quality of SiC surface.

In this study, biomass (oak, miscanthus, and sweet sorghum bagasse) are subjected to pretreatments involving either hydrothermal treatment followed by ball milling (HT/BM) or ball milling followed by hydrothermal treatment (BM/HT) in order to increase the enzymatic hydrolysis efficiency. The chemical composition and structure, and especially the crystallinity, of the treated biomass are found to depend on the order of pretreatment. The biomass obtained via hydrothermal treatment followed by 60 min of ball milling (HT/BM60) has a relatively low crystallinity (0-17.68 %) for all biomass, with the lowest value being obtained for miscanthus. Moreover, the particle size distribution span of the HT/BM60 miscanthus is low (0.79) compared to those of the other biomass due to an increased proportion of fine particles in the miscanthus. Meanwhile, the enzymatic hydrolysis efficiency of the HT/BM60 biomass is high, and the glucose conversion rate differs depending on the biomass, with the lowest in oak (55.91 %) and the highest in miscanthus (90.47 %). The enzyme adsorption isotherms and kinetics are suitable described by the Langmuir isotherm and pseudo-second-order model, thus implying chemical adsorption of the enzyme as a monolayer on the substrate surface. The principle component analysis shows the particle size and crystallinity of the biomass significantly affect the enzymatic hydrolysis.

The density of graphite insulation largely affects a temperature gradient of the horizontal direction of the hot-zone in SiC crystal growth using the physical vapor transport (PVT) method. Three types of stacking configurations of graphite insulation with different densities were implemented to graphite hot-zone. The stacking configuration adoption with denser graphite insulation at the seed region gives rise positive effect on the achievement of a convex crystal shape, no polytype inclusion, improvement of crystal quality as well as lower defect density due to maintainance of constant temperature gradient during the SiC crystal growth. These results were investigated using ultraviolet fluorescence (UVF) images, map of Full width at half maximum (FWHM) and shift of an X-ray rocking curve (Omega scan), and surface morphology analysis after molten KOH etching. Optimization of hot-zone design adopting with stacking configuration of graphite insulation led to high-quality SiC crystal through the PVT method.

A modified process condition has been proposed for the growth of high-quality 6-inch 4H-SiC single crystal. Temperature gradient (dT[°C] = T bottom -T upper ) was controlled by changing coil position in order to investigate the effect of the temperature gradient on the SiC crystal quality. SiC ingot surface and etch pit density (EPD) of etched SiC wafer were investigated according to different dT conditions at the initial stage of SiC crystal growth. The surface of SiC crystal ingots grown with different dT for 10h were observed by OM and etched SiC wafers were prepared from SiC crystal ingots after main growth step for 100h. Different dT conditions in the initial growth stage resulted in dramatically different surface images and the crystal quality evaluated by EPD.

Currently, humankind is facing a serious environmental and climate crisis, which has accelerated the research on producing bioenergy from waste biomass as a carbon-neutral feedstock. In this study, the aim was to develop an upcycling strategy for waste biomass to solid-type biofuel conversion for power generation. Various types of waste biomass (i.e., waste wood after lumbering, sawdust-type mushroom waste wood, kudzu vine, and empty fruit bunches from palm) were used as sustainable feedstocks for steam explosion-based torrefaction. The reaction conditions were optimized for each waste biomass by controlling the severity index (Ro); the higher heating value increased proportional to the Ro increase. Additionally, component analysis revealed that steam explosion torrefaction mainly degraded hemicellulose, and most of the torrefied waste biomass met the Bio-Solid Refuse Fuel quality standard. The results provide not only a viable waste-to-energy strategy but also insights to address global climate change.

Transition metal ion was added to CMP (chemical-mechanical polishing) slurry without abrasive particle to solve the problem of CMP. MRR (material removal rate) value of SiC substrate processed using non-abrasive slurry was comparable to MRR values of SiC substrates using abrasive slurries. The scratch formation was successfully suppressed in SiC substrate polished with using non-abrasive slurry and no residual particle resulting from agglomeration of abrasive particles could suppress scratches and forms a good quality of SiC substrate surface. Uniform and high-quality SiC substrates could be prepared through the non-abrasive CMP process.

In this study, the resistance characteristics of semi-insulating SiC single crystals grown using the PVT method were investigated, considering the purity level of SiC source powders used in PVT growth and the cooling procedure after crystal growth. Two (3-SiC powders with different purities were employed, and the cooling rate after growth was adjusted to achieve various resistance values. 4-inch HPSI-SiC ingots were grown using the PVT method, utilizing SiC powders with low nitrogen concentration and relatively high nitrogen concentration. These ingots were then subjected to different cooling procedures to modify the cooling rate. Transmission/absorption spectra and crystal quality of the grown crystals were analyzed through UV/VIs/NIR spectroscopy and X-ray rocking curve analysis, respectively. Additionally, electrical properties were investigated through non-contact resistivity analysis to identify the dominant factors influencing resistivity