Highly stretchable electric circuits from a composite material of silver nanoparticles and elastomeric fibres.

Park, Minwoo,Im, Jungkyun,Shin, Minkwan,Min, Yuho,Park, Jaeyoon,Cho, Heesook,Park, Soojin,Shim, Mun-Bo,Jeon, Sanghun,Chung, Dae-Young,Bae, Jihyun,Park, Jongjin,Jeong, Unyong,Kim, Kinam Nature Pub. Group 2012 Nature nanotechnology Vol.7 No.12

<P>Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (σ???2,200?S?cm(-1) at 100% strain for a 150-?m-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications.</P>

Effects of Pig Skin Collagen Supplementation on Broiler Breast Meat

Sanghun Park,Yun-a Kim,Sanghun Lee,Yunhwan Park,Nahee Kim,Jungseok Choi 한국축산식품학회 2021 한국축산식품학회지 Vol.41 No.4

This study aimed to enhance the quality of broiler breast meat by adding pig skin collagen to feed. A total of 50 Ross 308 broilers were classified according to the following feeding regime for two weeks: basal diet (NC), basal diet+0.1% fish collagen (PC), basal diet+0.1% pig skin collagen (T1), basal diet+0.5% pig skin collagen (T2), and basal diet+1.0% pig skin collagen (T3). The moisture content was the highest in the PC group, and the protein content was the lowest in the T1 group (p<0.05). The fat content was higher in the T1 and PC groups, whereas the ash content was higher in the T3 group (p<0.05). Drip loss was the highest in the NC group and the lowest in the T2 group (p<0.05). Lightness was low in groups T2 and T3, redness was low in groups T2 and PC, and yellowness was low in groups T1, T2, and PC (p<0.05). The collagen content of the chicken breast was the highest in the T3 group, and that of the skin was the highest in the T1 group (p<0.05). The texture characteristics of springiness, cohesiveness, chewiness, and hardness were the highest in the T3 group (p<0.05). In conclusion, the supplementation of a broiler diet with pig skin collagen was found to increase the collagen content of the breast meat, indicating the improved quality of the broiler breast meat.

Arctic Primary Aerosol Production Strongly Influenced by Riverine Organic Matter

Park, Jiyeon,Dall’Osto, Manuel,Park, Kihong,Kim, Jung-Hyun,Park, Jongkwan,Park, Ki-Tae,Hwang, Chung Yeon,Jang, Gwang Il,Gim, Yeontae,Kang, Sujin,Park, Sanghun,Jin, Yong Keun,Yum, Seong Soo,Simó American Chemical Society 2019 Environmental science & technology Vol.53 No.15

<P>The sources of primary and secondary aerosols in the Arctic are still poorly known. A number of surface seawater samples-with varying degrees of Arctic riverine and sea ice influences-were used in a sea spray generation chamber to test them for their potential to produce sea spray aerosols (SSA) and cloud condensation nuclei (CCN). Our interdisciplinary data showed that both sea salt and organic matter (OM) significantly influenced the SSA production. The number concentration of SSA in the coastal samples was negatively correlated with salinity and positively correlated with a number of OM tracers, including dissolved and chromophoric organic carbon (DOC, CDOM), marine microgels and chlorophyll <I>a</I> (Chl-<I>a</I>) but not for viral and bacterial abundances; indicating that OM of riverine origin enhances primary aerosol production. When all samples were considered, transparent exopolymer particles (TEP) were found to be the best indicator correlating positively with the ratio number concentration of SSA/salinity. CCN efficiency was not observed to differ between the SSA from the various samples, despite differences in organic characteristics. It is suggested that the large amount of freshwater from river runoff have a substantial impact on primary aerosols production mechanisms, possibly affecting the cloud radiative forcing.</P> [FIG OMISSION]</BR>

Correlation between the Korean pork grade system and the amount of pork primal cut estimated with AutoFom III

( Yunhwan Park ),( Eunyoung Ko ),( Kwangwook Park ),( Changhyun Woo ),( Jaeyoung Kim ),( Sanghun Lee ),( Sanghun Park ),( Yun-a Kim ),( Gyutae Park ),( Jungseok Choi ) 한국축산학회 2022 한국축산학회지 Vol.64 No.1

It is impossible to know the amount of pork primal cut by pig carcass grade which is determined only by carcass weight and backfat thickness in the Korean Pig Carcass System. The aim of this study was to investigate the correlation between the pig carcass grade and the amount of pork primal cut estimated with AutoFom III. A total of 419,321 Landrace, Yorkshire, and Duroc (LYD) pigs were graded with the Korean Pig Carcass Grade System. Amounts of belly, neck, loin, tenderloin, spare ribs, shoulder, and ham were estimated with AutoFom III. Regression equations for seven primal cuts according to each grade were derived. There were significant differences among the three carcass grades due to heteroscedasticity variance (p < 0.0001). Three regression equations were derived from AutoFom III estimation of primal cuts according to carcass grades. The coefficient of determination of the regression equation was 0.941 for grade 1⁺, 0.982 for grade 1, and 0.993 for grade 2. Regression equations obtained from this study are suitable for AutoFom III software, a useful tool for the analysis of each pig carcass grade in the Korean Pig Carcass Grade System. The high reliability of predicting the amount of primal cut with AutoFom III is advantageous for the management of slaughterhouses to optimize their product sorting in Korea.

Evaluating the effects of organic matter bioavailability on nanofiltration membrane using real-time monitoring

Park, Sanghun,You, Jeongyeop,Ahn, Yujin,Jung, Woonggyu,Kim, Jihye,Lee, Sungyun,Park, Jongkwan,Cho, Kyung Hwa Elsevier 2018 Journal of membrane science Vol.548 No.-

<P><B>Abstract</B></P> <P>We studied the influence of bioavailability of organic matter on membrane fouling layer development by comparing the filtration performance of two feed waters (wetland water and graywater). Dissolved organic carbon (DOC) concentration, size exclusion chromatography (SEC), and fluorescence excitation-emission matrix (FEEM) were used to characterize the bioavailability of organic matter in these water samples during the nanofiltration process. The wetland sample contained a high proportion of humic acid- and fulvic acid-like matter with low bioavailability, whereas the graywater sample comprised substantial amounts of aromatic proteins and microbial byproduct-like matter with high bioavailability. In addition, the molecular size distribution revealed that the wetland sample contained a large portion of recalcitrant organic matter, whereas the graywater sample contained easily bioavailable organic matter. After the filtration experiment, the DOC of the wetland sample decreased to 4.8mgC/L, whereas the graywater sample resulted in a lower DOC concentration of 3.4mgC/L. Optical coherence tomography (OCT) illustrated real-time variations in the fouling layer morphology, providing both 2D and 3D images. In addition, confocal laser scanning microscopy (CLSM) quantified the bacterial volume in the fouling layer. The wetland sample yielded a bacterial volume of 11.8µm<SUP>3</SUP>/μm<SUP>2</SUP> from a total fouling volume of 103µm<SUP>3</SUP>/μm<SUP>2</SUP>, whereas the graywater sample yielded a bacterial volume of 53.2µm<SUP>3</SUP>/μm<SUP>2</SUP> from a total fouling layer volume of 134µm<SUP>3</SUP>/μm<SUP>2</SUP>. Fitting of the two-phase Monod model to the fouling layer growth on the membrane resulted in lower-yield coefficients (i.e., the volumes produced per unit amount of substrate, <SUB> Y xs </SUB> ) of 7.46 and 27.95µm<SUP>3</SUP>/μm<SUP>2</SUP> in wetland water and higher-yield coefficients of 13.17 and 47.53µm<SUP>3</SUP>/μm<SUP>2</SUP> in the graywater at first and second phase, respectively. This study addresses the quantitative evaluation of the organic matter bioavailability in terms of membrane fouling using OCT images and a two-phase Monod model.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The difference of bioavailability of DOM influenced the amount of fouling layer growth. </LI> <LI> In situ OCT monitoring provided 2D and 3D morphology of the fouling layer and quantified the volume. </LI> <LI> Two-phase Monod model evaluated the influence of bioavailability of DOM on fouling layer growth. </LI> </UL> </P>

Enhancement of Photo-Current Conversion Efficiency in a CdS/CdSe Quantum-Dot-Sensitized Solar Cell Incorporated with Single-Walled Carbon Nanotubes.

Park, Hyunjune,Lee, Jongtaek,Park, Taehee,Lee, Sanghun,Yi, Whikun American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.2

<P>Cadmium sulfide (CdS) and cadmium selenide (CdSe) are sequentially assembled onto a nanocrystalline TiO2 film to create a quantum-dot (QD)-sensitized solar cell application by a successive ionic layer adsorption and reaction (SILAR) method. The results show that CdS and CdSe QDs have a complementary effect in the performance of light harvest of solar cell. Single-walled carbon nanotubes (SWNTs) are incorporated with a CdS/CdSe QDs solar cell by mixing them with TiC2 film to enhance electron transfer. SWNTs are also sprayed onto CdSe QDs (SWNTs onto CdSe) to apply p+ type properties of SWNTs. Absorbance is increased in a wide wavelength range. In particular, cells having the sprayed SWNTs onto the QDs show a clear increase in absorbance at a low wavelength region. The fill factor of CdS/CdSe QDs solar cell with SWNTs is higher than that without SWNTs, indicating the decrease in loss of electron from TiO2 to QDs. Short-circuit current in a QD-sensitized solar cell having SWNTs on CdSe shows maximum value. Photo-current conversion efficiency of cells is increased in both cell types containing SWNTs at 10~17% compared with pristine cells. We expect that solar cells using SWNTs will affect future energy technology and devices.</P>

Evaluation of fouling in nanofiltration for desalination using a resistance-in-series model and optical coherence tomography

Park, Jongkwan,Lee, Sungyun,You, Jeongyeop,Park, Sanghun,Ahn, Yujin,Jung, Woonggyu,Cho, Kyung Hwa Elsevier 2018 The Science of the total environment Vol.642 No.-

<P><B>Abstract</B></P> <P>Resistance-in-series models have been applied to investigate fouling behavior. However, it is difficult to model the influence of morphology on fouling behavior because resistance is indirectly calculated from the water flux and transmembrane pressure. In this study, optical coherence tomography (OCT) was applied to evaluate the resistance of the fouling layer based on fouling morphology. Sodium alginate, humic acid, and bovine serum albumin (BSA) with high salts concentrations (conductivity: 23 mS/cm) were used as model foulants. At the same total fouling resistance, BSA showed the highest cake layer thickness (BSA (114.5 μm) > humic acid (53.5 μm) > sodium alginate (20.0 μm)). However, a different order was found for the cake layer resistance (BSA > sodium alginate > humic acid). This indicates that fouling thickness is not correlated with cake layer resistance. According to the Carman–Kozeny equation, fouling layer porosity decreased in the following order: humic acid (0.30) > BSA (0.21) > sodium alginate (0.20). In addition, we provided a specific value that was calculated using the ratio between the fouling thickness and cake layer resistance. The results show that alginic acid induced a stronger cake layer resistance, despite its thin fouling layer, whereas BSA showed a relatively low potential for inducing cake layer resistance. The results obtained in this study could be used for estimating and predicting fouling behavior.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Property of fouling layer was investigated by the membrane resistance value and fouling thickness. </LI> <LI> Humic acid, sodium alginate, and BSA fouling layers in brackish water were visualized via OCT. </LI> <LI> Gel/cake layer and adsorbed/pore blocking fouling types were distinguished by 2D OCT images. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Phase-controlled synthesis of SnO_x thin films by atomic layer deposition and post-treatment

Park, Bo-Eun,Park, Jaehong,Lee, Sangyoon,Lee, Sanghun,Kim, Woo-Hee,Kim, Hyungjun Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.480 No.-

<P><B>Abstract</B></P> <P>Tin oxide (SnO<SUB>x</SUB>) is a promising oxide semiconductor due to the distinct properties of n-type SnO<SUB>2</SUB> and p-type SnO based on its stoichiometry. However, the stoichiometry control of SnO<SUB>x</SUB> remains challenging due to the thermodynamic instability of SnO. In the study, we focus on establishing the controllable stoichiometry of SnO<SUB>x</SUB> via atomic layer deposition (ALD) and subsequent treatment. The controllable synthesis of SnO<SUB>2</SUB> and SnO is investigated by multiple analyses involving the chemical composition, crystal structure, and band structure. The ALD SnO<SUB>x</SUB> is composed mostly of Sn<SUP>4+</SUP> O bonds with intrinsic oxygen vacancies and is transformed into crystalline SnO<SUB>2</SUB> phase via post-annealing. The refractive index (~1.8) and optical bandgap energy (~3.6 eV) of ALD SnO<SUB>x</SUB> correspond to those of SnO<SUB>2</SUB>. Post-deposition treatment with H<SUB>2</SUB> plasma enables the effective transformation of SnO<SUB>2</SUB> into SnO due to the easy penetration of H<SUP>+</SUP> ion into the film and de-bonding of SnO via ion bombardment. The transformed SnO exhibits a significant amount of Sn<SUP>2+</SUP> O bonds with a refractive index of 2.8 and optical bandgap energy of ~2.9 eV. Specifically, the transformed SnO exhibits promise as an oxide semiconductor because it exhibits excellent stability with respect to re-oxidation into SnO<SUB>2</SUB> or further reduction into Sn metal. The present study advances practical applications that require a stable p-n junction through n-type SnO<SUB>2</SUB> and p-type SnO in various forms of device architectures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Formation of SnO<SUB>2</SUB> and SnO was controlled by atomic layer deposition and post-process. </LI> <LI> Chemical composition, crystal structure, and band structure of SnO<SUB>x</SUB> were analyzed. </LI> <LI> As-deposited SnO<SUB>x</SUB> exhibits typical characteristics of SnO<SUB>2</SUB>. </LI> <LI> Post-deposition treatment with H<SUB>2</SUB> plasma effectively transforms SnO<SUB>2</SUB> into SnO. </LI> <LI> Transformed SnO is stable against re-oxidation or reduction during post-process. </LI> </UL> </P>

Pathogen Associated Molecular Pattern (PAMP)-Triggered Immunity Is Compromised under C-Limited Growth

Park, Hyeong Cheol,Lee, Shinyoung,Park, Bokyung,Choi, Wonkyun,Kim, Chanmin,Lee, Sanghun,Chung, Woo Sik,Lee, Sang Yeol,Sabir, Jamal,Bressan, Ray A.,Bohnert, Hans J.,Mengiste, Tesfaye,Yun, Dae-Jin Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.1

In the interaction between plants and pathogens, carbon (C) resources provide energy and C skeletons to maintain, among many functions, the plant immune system. However, variations in C availability on pathogen associated molecular pattern (PAMP) triggered immunity (PTI) have not been systematically examined. Here, three types of starch mutants with enhanced susceptibility to Pseudomonas syringae pv. tomato DC3000 hrcC were examined for PTI. In a dark period-dependent manner, the mutants showed compromised induction of a PTI marker, and callose accumulation in response to the bacterial PAMP flagellin, flg22. In combination with weakened PTI responses in wild type by inhibition of the TCA cycle, the experiments determined the necessity of C-derived energy in establishing PTI. Global gene expression analyses identified flg22 responsive genes displaying C supply-dependent patterns. Nutrient recycling-related genes were regulated similarly by C-limitation and flg22, indicating re-arrangements of expression programs to redirect resources that establish or strengthen PTI. Ethylene and NAC transcription factors appear to play roles in these processes. Under C-limitation, PTI appears compromised based on suppression of genes required for continued biosynthetic capacity and defenses through flg22. Our results provide a foundation for the intuitive perception of the interplay between plant nutrition status and pathogen defense.

Study of Helium Irradiation Effect on W-Ta Alloy Thin Films

Sanghun Park,Haechan Jo,Dongwoo Lee 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.7