• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.298-298
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• 2014

Quantum dot infrared photodetectors (QDIPs) based on Stranski-Krastanov (SK) quantum dots (QDs) have been widely explored for improved device performance using various designs of heterostructures. However, one of the biggest limitations of this approach is the "pancake" shape of the dot, with a base of 20-30 nm and a height of 4-6 nm. This limits the 3D confinement in the quantum dot and reduces the ratio of normal incidence absorption to the off-axis absorption. One of the alternative growth modes to the formation of SK QDs is a sub-monolayer (SML) deposition technique, which can achieve a much higher density, smaller size, better uniformity, and has no wetting layer as compared to the SK growth mode. Due to the advantages of SML-QDs, the SML-QDIP design has attractive features such as increased normal incidence absorption, strong in-plane quantum confinement, and narrow spectral wavelength detection as compared with SK-DWELL. In this study, we report on the improved device performance of InAs/InGaAs SML-QDIP with different composition of $Al_xGa1-_xAs$ barrier. Two SML-QDIPs (x=0.07 for sample A and x=0.20 for sample B) are grown with the 4 stacks 0.3 ML InAs. It is investigated that sample A with a confinement-enhanced (CE) $Al_{0.22}Ga_{0.78}As$ barrier had a single peak at $7.8{\mu}m$ at 77 K. However, sample B with an $Al_{0.20}Ga_{0.80}As$ barrier had three peaks at (${\sim}3.5{\mu}m$, ${\sim}5{\mu}m$, ${\sim}7{\mu}m$) due to various quantum confined transitions. The measured peak responsivities (see Fig) are ~0.45 A/W (sample A, at $7.8{\mu}m$, $V_b=-0.4V$ bias) and ~1.3 A/W (sample B, at $7{\mu}m$, $V_b=-1.5V$ bias). At 77 K, sample A and B had a detectivity of $1.2{\times}10^{11}cm.Hz^{1/2}/W$ ($V_b=-0.4V$ bias) and $5.4{\times}10^{11}cm.Hz^{1/2}/W$ ($V_b=-1.5V$ bias), respectively. It is obvious that the higher $D^*$ of sample B (than sample A) is mainly due to the low dark current and high responsivity.

• Journal of Yeungnam Medical Science
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• v.16 no.1
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• pp.60-68
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• 1999

A nationwide survey was conducted to investigate the annual occurrence rate of neonatal sepsis, maternal risk factors in neonatal sepsis, localized infection in neonates, causative organisms in nosocomial infection and the most common causative organism for neonatal sepsis in Korea. Clinical and bacteriological data wele collected from 37 neonatal units to perform retrospective review of the medical records of the newborn infants who were confirmed as having neonatal sepsis and whose blood culture was collected to isolate organisms for one year study period from January to December in 1997. 78,463 neonates were born at 37 hospital in 1997, and 20,869 neonates were admitted to the neonatal units, During this period, 772 episodes of neonatal sepsis were recorded in 517 neonates. The occurrence rate of neonatal sepsis was 0.73%(0~2.95%). Male to female ratio was 1.15:1, and 303 cases(42.1%) were born prematurely. The main pathogens of early onset of sepsis were S. aureus(20%), S. epidermidis(14.4%) and coagulase negative staphylococcus(14. 4%). Gram negative bacilli including Enterobacter spp (7.2%), E. coli(5.1%), Klepstella(4.5%), Pseudomonas(3.7%) and Enterobacter faectum(3.6%) accounted for 24.1% of sepsis. Group B beta-hemolytic streptococcus were isolated only in two cases. Common obstetric factors were PROM(21.1%), difficulty delivery(18.7%), fetal tachycardia(5.3%), chorioamnionitis(4.9%), and maternal fever(4.7%). The main pathogens of late-onset sepsis were S. aureus(22.3%), S. epidermidis(20.4%) and CONS(9.9%). There were 6 cases(1.0%) of Candida sepsis, Frequent focal infections accompanying sepsis were pneumonia(26.1%), urinary tract infection(10.5%), meningitis(8.2%), and arthritis(3.6%), S. epidermidis(22.0%) and s. aureus(21.7%) were also the most common pathogens in 373 nosocomial infection.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.419-427
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• 2005

For the purpose to verify the physico­chemical properties of Korean waxy wheat, comparative analyses between waxy wheat lines and their respective maternal parents were performed on mixing and pasting properties, and flour particle sizes. The particle sizes of waxy wheat flour were significantly larger than those of their parents when milled in a same condition. Although the protein contents of flour in waxy wheat lines tested were high as much as those of bread wheat, the quality parameters showed lower baking uses based on sedimentation volumes and mixing characteristics. Waxy flour required more water than non-waxy flour to obtain the proper mixogram. Waxy wheat flour showed more or less higher onset pasting temperatures and much higher breakdown viscosities than their respective parent flour in the Rapid Viscograph test. Moreover, peak viscosity temperatures and final viscosities were dramatically reduced in waxy wheat lines by showing $79.4 - 81.7^{\circ}C$ and 101 ­116.9 RVU, respectively, compared to their parents in that the temperatures above $95^{\circ}C$ and the viscosity ranges of 148 -171.8 RVU.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.428-434
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• 2005

For the purpose to verify the grain and evaluate milling properties of Korean waxy wheat, com­parison analysis between waxy wheat lines and their respective maternal parents were performed. The waxy lines showed various grain yields of 4.76${\~}$5.79 t/ha depending on parentages, which were corresponding to $80{\~}96\%$ levels of their respective maternal parents. One thousand grain weights of waxy lines were also lighter than its respective part in its parentage by exhibiting 32.8${\~}$34.6 g compared to 32.9${\~}$45.2 g of their parents. Test weights of waxy lines and their parents were 720${\~}$798 g/l and 786${\~}$797 g/l, respectively. The proportions of the grains above 2.5 mm in width were higher in order of Keumgang, Olgeuru, Geuru, SW97134, Suwon 292, Woori, SW97105, and SW97110. Waxy lines exhibited low milling properties by showing the straight flour yields ranging from $61.8\%$ to $67.1\%$ compared with the yields of their parents ranging from $66.1\%$ to $72.5\%$; the waxy lines were significantly lower in first break flour (Bl) and first reduction flour (Rl) yields in the Buller test mill, while significantly higher in the yields of second and third reduction flour (R2 and R3) than the respective ones of their parent wheat.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.38-46
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• 2005

To determine the actual hygienic status of domestic chicken meats sold in public markets (conventional markets and department stores), microbial contamination levels (Total cells, Coliforms and Staphylococcal cells) and zoonotic pathogens (Salmonella species, Campylobacter species, Listeria species, and Staphylococcus aureus) isolation tests were conducted. Chicken meats and eggs tested were collected from the conventional markets (Si-Jang) and department-stores located in Seoul and Kyung-gi regions in 1996. In total cells and coliforms contamination tests, chicken meats sold in department stores were much lesser contamination status than those of Si-Jang, but staphylococcal cells level was much more higher than that of conventional markets. Salmonella isolation frequency was investigated as $68.8\%$, but Campylobacter jejuni and Listeria monocytogenes isolation frequency were appeared both $64.0\%\;and\;63.3\%$. In case of eggs sold in public markets, one of S. gallinarum strain $(0.7\%)$ was isolated only on the egg-shell part among the four-hundred and fourty-six. In comparison with foreign imported chicken meats, there were no big differences in microbial contamination status. On the other hand, both Salmonella and L. monocytogenes were isolated only in the chicken wings from Korea and China, but not from U.S.A. This data suggest that more hygienic control system in order to produce the safe and hygienic chicken meats and eggs is need in our country as soon as possible.

• Herbal Formula Science
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• v.22 no.2
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• pp.105-120
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• 2014

Objectives : This study was investigated the improvement effects of Gangjihwan (DF) and combination of Gangjihwan and Gamisochehwan (GSH) on obesity in a high fat diet-fed obese mouse model. Methods : Eight-week-old C57BL/6N mice were divided into four groups: a normal lean group given a standard diet, an obese control group given a high fat diet, and DF and DF+GSH groups given a high fat diet with DF (40 mg/kg), and DF+GSH (80 mg/kg), respectively. After 8 weeks of treatment, body weight gain, feeding efficiency ratio, blood lipid markers, fat weight and histology were examined. Results : 1. Body weight gain and fat mass were significantly decreased in DF and DF+GSH groups compared with control. The extent of decreases was eminent in DF+GSH group. 2. Feeding efficiency ratio and circulating concentration of leptin were decreased in DF and DF+GSH groups compared with control. These decreases were significant in DF+GSH group. 3. Consistent with their effects on body weight gain and fat mass, circulating concentrations of triglyceride, glucose and insulin were decreased in DF and DF+GSH groups compared with control. 4. The size of adipocytes was decreased by DF and DF+GSH compared with control, whereas the adipocyte number per unit area was increased by them, suggesting that DF and DF+GSH decreased the number of large adipocytes. 5. Consistent with their effects on body weight gain, liver fibrosis was also improved in DF and DF+GSH groups compared with control. Conclusions : In conclusion, these results suggest that DF and DF+GSH groups decrease feeding efficiency ratio, plasma leptin concentration, blood anti-obesity biomarkers and fat mass, improves body weight gain contributing to the inhibition of liver fibrosis. In addition, these effects were more effective in DF+GSH combination group than in DF-only group.

• Journal of the Korean Magnetics Society
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• v.15 no.6
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• pp.315-319
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• 2005

To obtain low switching field ($H_{SW}$) we introduced amorphous ferromagnetic $Co_{70.5}Fe_{4,5}Si_{15}B_{10}$ single and synthetic antiferromagnet (SAF) free layers in magnetic tunnel junctions (MTJs). The switching characteristics for MTJs with structures $Si/SiO_2/Ta$ 45/Ru 9.5/IrMn 10/CoFe 7/AlOx/CoFeSiB 7 or CoFeSiB (t)/Ru 1.0/CoFeSiB (7-t)/Ru 60 (in nm) were investigated and compared to MTJs with $Co_{75}Fe_{25}$ and $Ni_{80}Fe_{20}$ free layers. CoFeSiB showed a lower saturation magnetization of $560 emu/cm^3$ and a higher anisotropy constant of $2800\;erg/cm^3$ than CoFe and NiFe, respectively. An exchange coupling energy ($J_{ex}$) of $-0.003erg/cm^2$ was observed by inserting a 1.0 nm Ru layer in between CoFeSiB layers. In the CoFeSiB single and SAF free layer MTJs, it was frond that the size dependence of the $H_{SW}$ originated from the lower $J_{ex}$ experimentally and by micromagnetic simulation based on the Landau-Lisfschitz-Gilbert equation. The CoFeSiB SAF structures showed lower $H_{SW}$ than that of NiFe, CoFe and CoFeSiB single structures. The CoFeSiB SAF structures were proved to be beneficial far the switching characteristics such as reducing the coercivity and increasing the sensitivity in micrometer to submicrometer-sized elements.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.4
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• pp.430-435
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• 2009

The effects of turmeric and fermented turmeric by Bacillus natto on antioxidant activities, liver function recovery of acute hepatotoxicity mice, and serum lipid parameters in high fat diet fed mice were investigated. In the results of antioxidant activity by DPPH method, fermented turmeric had higher antioxidative activity than turmeric. Acute hepatotoxicity was induced by 0.5 mL of carbon tetrachloride ($CCl_4$) per kg of mice. Unlike turmeric, fermented turmeric significantly reduced the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) after 5 days compared to the controls with 0.5% methyl cellulose (p<0.05). In addition, higher recovery of liver damage by $CCl_4$ was observed in mice with fermented turmeric than with turmeric. High fat (20%) diet fed mice were divided into 4 groups to investigate the effects of turmeric and fermented turmeric on serum lipid parameters: C (vehicle), TuL (low dose (80 mg/kg) with turmeric), TuH (high dose (160 mg/kg) with turmeric), FTuL (low dose with fermented turmeric), and FTuH (high dose with fermented turmeric). The levels of LDL-cholesterol and HDL-cholesterol were significantly reduced and increased in FTuL, FTuH and TuH groups compared to the C group, respectively. However, there was no significant change in triglyceride levels by either turmeric or fermented turmeric compared to those by control. Collectively, these results strongly suggest that fermented turmeric by Bacillus natto could be used as a functional food for enhancement of health with better consumer acceptance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.1
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• pp.41-50
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• 2012

The study was carried out to analyze the relationship between analysis of antioxidant activity and the level of functional components according to particle size of corn silk. Particle size was classified into 5 groups. By particle size distribution and color difference, the total phenol content and DPPH radical scavenging activity were observed. The particle sizes of corn silk were $199.17{\mu}m$, $178.27{\mu}m$, $85.48{\mu}m$, $27.4{\mu}m$ and $20.97{\mu}m$, respectively. The lightness of colored pigments was increased when the particle size was decreased. The contents of free sugar (fructose, glucose, galactose, sucrose, and maltose) of corn silk were analyzed using a HPLC. The total phenol contents by the particle sizes of corn silk were 2.01 mg/g, 2.02 mg/g, 2.06 mg/g, 2.26 mg/g and 2.26 mg/g, respectively. DPPH radical scavenging activities of samples were 21.00%, 21.75%, 22.90%, 24.35% and 23.67%, respectively. Antioxidative activities of Trolox and Fe(II) in corn silk were measured by ferric reducing antioxidant power (FRAP) assay and Trolox equivalent antioxidant capacity (TEAC) assay. TEAC values of samples were $2.36{\mu}mol$ TE / g dw, $2.81{\mu}mol$ TE / g dw, $3.20{\mu}mol$ TE / g dw, $3.36{\mu}mol$ TE / g dw, and $3.44{\mu}mol$ TE / g dw, respectively. FRAP values of samples were $11.67{\mu}mol$ Fe(II) / g dw, $12.80{\mu}mol$ Fe(II) / g dw, $13.43{\mu}mol$ Fe(II) / g dw, $13.85{\mu}mol$ Fe(II) / g dw and $15.95{\mu}mol$ Fe(II) / g dw, respectively. Total phenolic content and antioxidantive activities based on FRAP assay and TEAC assay were increased with decreasing particle size. In addition, DPPH radical scavenging activity was also increased. A significant correlation was also noted between DPPH radical scavenging activities and the content of phenolic compounds.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.343-354
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• 2008

The objective of this study was to investigate the effect of restricted feeding to pullet on growth and endocrine profile in layers(Isa brown). One thousand eighty brown-layer chicks were divided into three treatments; conventional feeding(ad libitum) and two restricted feedings(80% of conventional diet) for 70 weeks. One of restricted feeding started from seven to seventeen weeks of age, and the other started from twelve to seventeen weeks of age. Diets were formulated by NRC(1994) recommendation. Body weight and feed intake were measured every two weeks, and body composition and organ weight analyzed every week in rearing period and every eight weeks in laying period. Blood was collected at weighing body weight and was analyzed for the concentration of insulin-like growth factor-Ⅰand estradiol. Body weight and feed intake decreased as restriction of feeding begins comparing to ad libitum group(P<0.05), but reached to similar body weight and feed intake at 20 wk of age regardless of restriction. There were no significant differences in development of digestive tract and attached organs among the treatment groups. During rearing period, however, they were slightly higher in restricted group which was low in body weight. In terms of body composition, fat contents of restricted group were significantly lower(P<0.05) than that of ad libitum group around 1,000 grams of body weight. High concentration of IGF-Ⅰwas observed.