Effect of SiC and ZnO Nanoparticles on UV Absorbance and Heat Transfer of PET Composite Film     

Sung Won Park  Hye Mi Choi  Dong Soo Shin  Tae Hwan Oh 《Fibers and Polymers》2018,19(1):188-194

Zinc oxide (ZnO) and silicon carbide (SiC) nanoparticles were compounded with polyethylene terephthalate (PET) by using a twin screw extruder, and their effect on the UV absorption and heat transfer in PET/ZnO and PET/SiC composite films was investigated. The presence of ZnO and SiC in the PET matrix was verified by X-ray diffraction. The UV absorbance of both PET/ZnO and PET/SiC composite films increased with increasing particle content. The UV absorbance of PET/SiC was higher than that of PET/ZnO under the same particle content. A thermal imaging camera was used to analyze the heat transfer in PET/ZnO and PET/SiC composite films after heating them to 40 °C. As the content of ZnO and SiC particles increased, the temperature decreased more rapidly. PET/SiC showed faster cooling than PET/ZnO because of the higher thermal conductivity of SiC compared to that of ZnO. Response temperature surfaces for PET/ZnO and PET/SiC were obtained by using an exponential decay function and a second order equation, and the elapsed times to cool to room temperature were estimated.  相似文献   

Transcrytalline structures and crystallization kinetics of Polyarylate/Nylon6 Islands-in-a-Sea conjugate fibers for high performance thermoplastic composite applications     

Jinho Park  Sung Chan Lim  Jong Sung Won  Seung Goo Lee  Wan Gyu Hahm  Jong Kyoo Park  Young Gyu Jeong 《Fibers and Polymers》2016,17(6):827-835

We report the isothermal and non-isothermal crystallization kinetics and associated transcrystalline morphological features of polyarylate(PAR)/nylon6 islands-in-a-sea fibers, where 74 PAR islands serve as reinforcing fibers and nylon6 sea component acts as a semicrystalline matrix in final thermoplastic composites. The temperature-dependent polarized optical microscopic images obtained during a cooling process exhibit that the melt-crystallization is dominated by the interfacial crystallization of nylon6 on the surface of PAR fibers, leading to developing a transcrystalline structure. From the isothermal and non-isothermal melt-crystallization analyses of the islands-in-a sea fiber by using differential scanning calorimetry and the Avrami equation, the overall crystallization rates of the nylon6 sea component in the islands-in-a-sea fiber are found to be highly accelerated by the heterogeneous nucleating effect of the PAR island fibers. In addition, it is revealed that the isothermal and non-isothermal melt-crystallization kinetics of the nylon6 in the islands-in-a-sea fibers consists of two different mechanisms of the primary crystallization owing to the interfacial crystallization and the secondary crystallization due to the bulk crystallization.  相似文献   

Effect of solvent and blended polymer on electrical conductivity of PEDOT:PSS/polymer blended nanofibers     

Sung Won Park  Tae Hwan Oh  Jun Sung Hwang  Young Jae Lee 《Fibers and Polymers》2016,17(8):1171-1174

Poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) and polyethylene oxide (PEO) (or polyvinyl alcohol (PVA)) blended electrospun nanofibers were prepared in the presence of dimethyl sulfoxide (DMSO) and ethylene glycol (EG). The effects of added solvents (DMSO and EG) and blended polymers (PEO and PVA) on electrical conductivity and current-voltage (I-V) response were investigated. Electrical conductivity was dependent on both the additional solvent and blended polymers. PEDOT:PSS/PEO blended nanofibers showed a much higher electrical conductivity than PEDOT:PSS/PVA. EG blended PEDOT:PSS/PEO blended nanofibers showed much higher electrical conductivity than DMSO. The PEDOT:PSS/PEO/EG blended nanofibers web showed the highest value in I-V response.  相似文献   

A diazotrophic, indole-3-acetic acid-producing endophyte from wild cottonwood     

Gang Xin  Gengyun Zhang  Jun Won Kang  James T. Staley  Sharon L. Doty 《Biology and Fertility of Soils》2009,45(6):669-674

An endophytic bacterium, wild poplar strain B (WPB), isolated from stems of wild cottonwood (Populus trichocarpa) was identified to Burkholderia vietnamiensis by analyzing the recA and rDNA genes. Phylogenetic analysis of the nifHDK cluster indicates that the WPB isolate shares high sequence similarity with known B. vietnamiensis strains. The nitrogenase activity of WPB was determined by a ¹⁵N₂ incorporation assay and an acetylene reduction assay. WPB was also monitored for production of indole-3-acetic acid (IAA), a phytohormone which can promote plant growth, when incubated with l-tryptophan. In addition, its plant growth promotion capacity was assessed by inoculating the WPB strain onto Kentucky bluegrass in nitrogen-free medium. Compared to uninoculated control plants, the plants inoculated with WPB gained more dry weight (42%, p = 0.01) and more nitrogen content (37%, p = 0.04) in 50 days.  相似文献   

Comparative observation of freeze–thaw-induced damage in pig, rabbit, and human corneal stroma     

Joo Youn Oh  †  ‡  Mee Kum Kim  †  ‡  Hyun Ju Lee  †  ‡  Jung Hwa Ko  †  ‡  Won Ryang Wee  †  ‡  Jin Hak Lee  †  ‡ 《Veterinary ophthalmology》2009,12(S1):50-56

Objective  Although variations exist between species with respect to outcomes after cryopreservation, little is known about the differences in the susceptibility of the corneal stroma to cryoinjury. We performed this study to investigate freeze–thaw-induced damage in keratocytes and collagen in rabbit, pig, and human corneas.
Animals studied  Rabbit, pig, and human.
Procedures  We prepared 250-μm-thick anterior stroma from rabbit, pig, and human corneas after scraping off the epithelium and endothelium. Each 250-μm-thick corneal stroma without epithelium was placed in a 50-mL tube, frozen with liquid N₂ for 15 min and taken out to thaw rapidly at 37 °C. This procedure of rapid freezing and thawing was repeated three times. Differences between the species with respect to cells and collagen structures were examined using hematoxylin–eosin (H&E) staining, terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay, and transmission electron microscopy (TEM). We orthotopically transplanted the pig and rabbit corneal transplants after the triple freeze–thaw cycle into rabbit eyes and evaluated graft survival.
Results  On gross examination, rabbit corneas became opaque after the triple freeze–thaw procedure, while pig and human corneas remained transparent. Histologically, keratocytes were apoptotic on TUNEL assay and TEM in rabbit, pig, and human corneas. Collagen fibrils were fragmented and the arrangement of collagen fibrils was severely disturbed in rabbit corneas on H&E staining and TEM; collagen was well preserved in pig and human corneas. Rabbit corneal stroma underwent autolysis after transplantation, whereas the pig corneal stroma remained clear for 1 month.
Conclusions  Our study showed that rabbit corneal stroma was more susceptible to freeze–thaw injury than pig and human corneas.  相似文献   

Anti-obesity activity of diglyceride containing conjugated linoleic acid in C57BL/6J ob/ob mice     

Jin-Joo Hue  Ki Nam Lee  Jae-Hwang Jeong  Sang-Hwa Lee  Young Ho Lee  Seong-woon Jeong  Sang Yoon Nam  Young Won Yun  Beom Jun Lee 《Journal of veterinary science (Suw?n-si, Korea)》2009,10(3):189-195

This study was to investigate the anti-obesity effects of diglyceride (DG)-conjugated linoleic acid (CLA) containing 22% CLA as fatty acids in C57BL/6J ob/ob male mice. There were four experimental groups including vehicle control, DG, CLA, and DG-CLA. The test solutions of 750 mg/kg dose were orally administered to the mice everyday for 5 weeks. CLA treatments significantly decreased mean body weight in the obese mice throughout the experimental period compared to the control (p < 0.01). All test solutions significantly decreased the levels of triglyceride, glucose and free fatty acids in the serum compared with control (p < 0.05). The levels of total cholesterol were also significantly reduced in DG and DG-CLA groups compared with the control group (p < 0.05). CLA significantly decreased weights of renal and epididymal fats compared with the control (p < 0.05). DG and DG-CLA also significantly decreased the epididymal fat weights compared with the control (p < 0.05). A remarkable decrease in the number of lipid droplets and fat globules was observed in the livers of mice treated with DG, CLA, and DG-CLA compared to control. Treatments of DG and CLA actually increased the expression of peroxisome proliferator-activated receptor gamma. These results suggest that DG-CLA containing 22% CLA have a respectable anti-obesity effect by controlling serum lipids and fat metabolism.  相似文献   

Trophic structure in natural habitats of the abalone Haliotis discus hannai with distinct algal vegetation of kelp and crustose coralline algae: implication of ontogenetic niche shifts     

Nam-Il Won  Tomohiko Kawamura  Hideki Takami  Yoshiro Watanabe 《Fisheries Science》2013,79(1):87-97

The abundance, species composition, and stable isotope ratios of benthic organisms were investigated to determine the trophic structures in abalone (Haliotis discus hannai) habitats, which are characterized by contrasting vegetation of crustose coralline algae (CCA) and kelp beds. A size–frequency analysis revealed that juvenile abalones with shell lengths (SLs) smaller than ~30 mm primarily inhabited CCA beds, whereas adults were abundant in kelp beds. Stable isotope analyses indicated that CCA beds were composed of a single food chain, whereas kelp beds supported multiple food chains. The abalone were divided into three size groups to estimate potential species interactions during their ontogeny. A small gastropod, Homalopoma sangarense, was the most abundant species, but is suspected to be less competitive with abalone, especially in CCA beds. An abundant starfish Asterina pectinifera appeared to function as a potential predator of juvenile abalones in both CCA and kelp beds. We concluded that CCA beds are essential for immediate post-settlement processes of abalones, whereas kelp beds are more important for providing refuge and food sources for adult abalones. The present study highlights that ontogenetic niche shifting can be a successful life-history strategy to sustain the abalone population in a subtidal rocky shore ecosystem.  相似文献   

Silsesquiazane/organic polymer blends as organic-inorganic hybrid materials     

Kwang Hee Yoo  Il Won Kim  Jeong Ho Cho  Young-Je Kwark 《Fibers and Polymers》2012,13(9):1113-1119

Silsesquiazane (SSQZ), one of the branched forms of polysilazane, was blended with polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(iso-butyl methacrylate) (PBMA), and poly(vinyl acetate) (PVAc) to produce organic-inorganic hybrid materials. The polymers were selected to provide specific interaction, such as ??-?? interaction or hydrogen bonding, with SSQZ. AFM studies revealed that carbonyl containing polymers, PMMA, PBMA, and PVAc were miscible with SSQZ while PS was immiscible. DSC analysis of the hybrids also supported the miscibility behaviours of the system. The glass transition behaviour of SSQZ/PS showed individual transition temperature corresponding to the each component while SSQZ/carbonyl-containing polymers displayed one transition temperature that matched with the theoretically calculated values following the Kwei equation. Among the miscible hybrid system, the interaction with SSQZ increased in the order of PMMA> PBMA> PVAc, as determined by the q value in the Kwei equation. This result was confirmed by determining the degree of hydrogen bonding in FT-IR spectra. Thermal stability of organic polymers was improved by incorporating SSQZ regardless of the miscibility.  相似文献   

Taste Compounds and Biofunctional Activities of the Sandy Beach Clam Hydrolysate for the Shellfish Flavoring Condiment     

Won Il Cho 《Journal Of Aquatic Food Product Technology》2013,22(1):24-34

ABSTRACT

Sandy beach clam meat was hydrolyzed with proteases (Alcalase and Flavozyme) for the manufacture of a natural flavoring condiment. The optimal conditions for the enzymatic hydrolysis of the shellfish meat via the response surface methodology were: temperature, 54.7°C; pH, 5.9; time, 45 h. The total amino acid content of the shellfish hydrolysate was 9,218.8 mg/100 g and consisted mainly of glutamic acid, aspartic acid, glycine, arginine, lysine, and leucine. Nucleotides and their related compounds of the shellfish hydrolysate consisted mainly of adenosine diphosphate (0.86 mg/100 g), adenosine monophosphate (11.24 mg/100 g), and inosine (49.03 mg/100 g). The shellfish hydrolysate resulted in three protein peaks in the Bio-Rad P2 gel chromatography pattern. The antioxidant activity was highest at Peak 1 (64.67%), followed by Peak 2 (27.48%) and Peak 3 (16.67%); whereas the angiotensin I-converting enzyme inhibitory activity was highest at Peak 3 (67.27%), followed by Peak 2 (6.14%). Antitumor activity was highest at Peak 1 (18.77%), followed by Peak 2 (8.75%). All the sensory attributes of the shellfish condiment were scored highly. Therefore, the sand beach clam hydrolysate can be commercialized as an ingredient of a natural flavoring condiment or seasoning.  相似文献   

Effects of road transportation on metabolic and immunological responses in Holstein heifers          下载免费PDF全文

Hyeok‐Joong Kang  In Kyu Lee  Min‐Yu Piao  Chae‐Won Kwak  Min Jeong Gu  Cheol Heui Yun  Hyun‐Jin Kim  Hyeon‐Ju Ahn  Hee‐Bal Kim  Gyeom‐Heon Kim  Soo‐Ki Kim  Jong‐Youl Ko  Jong K. Ha  Myunggi Baik 《Animal Science Journal》2017,88(1):140-148

This study examined the effects of road transportation on metabolic and immunological responses in dairy heifers. Twenty Holstein heifers in early pregnancy were divided into non‐transported (NT; n = 7) and transported (T; n = 13) groups. Blood was collected before transportation (BT), immediately after transportation for 100 km (T1) and 200 km (T2), and 24 h after transportation (AT). The T heifers had higher (P < 0.05) blood cortisol and non‐esterified fatty acid concentrations after T1 and T2 than did NT heifers. By contrast, the T heifers had lower (P < 0.05) serum triglyceride concentrations after T1 and T2 than had the NT heifers. The serum cortisol and triglyceride concentrations returned (P > 0.05) to the BT concentrations at 24 h AT in the T heifers. The granulocyte‐to‐lymphocyte ratio and the percentage of monocytes were higher (P < 0.05) after T2 in the T heifers than in the NT heifers, suggesting that transportation stress increased the numbers of innate immune cells. T heifers had higher (P < 0.01) plasma haptoglobin concentrations than NT heifers 24 h AT. In conclusion, transportation increased cortisol secretion and was correlated with increased metabolic responses and up‐regulation of peripheral innate immune cells in dairy heifers.  相似文献