• Journal of the Korean Vacuum Society
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• v.3 no.3
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• pp.346-354
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• 1994

삼원화합물 반도체 CuAlSe2 및 CuGaSe2 단결정의 solid solution 인 CuAl1-xGaxSe2 및 cobalt를 2.0 mol% 첨가한 CuAl1-xGaxSe2 : Co2+ 단결정을 iodine을 수송물질로 사용한 화학수송법으로 성장시켰 다. source material로는 CuAl1-xGaxSe2 의 화학조성비에서 Se를 3.0mol% 과잉으로 첨가하여 합성한 ingot를 사용하였으며 불순물이 첨가된 CuAl1-xGaxSe2:Co2+ 단결정성장시에는 source ma-terial 에 cobalt 분말을 2.0mol% 첨가하였다. X-선 회절무늬로부터 성장된 단결정들이 chalcopyrite 결정구조를 하고 있음을 확인하였으며 격자상수를 구하였다. 광흡수 spectra 측정으로부터 성장된 단결정에서 나타 는 cobalt 불순물에 의한 광흡수 peak가 Td 대칭점에위치한 Co2+ 이온의 에너지 준위들간 전자전이에 의해 나타남을 규명하였다.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.939-942
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• 2008

Photoelectrochemical deposition of CdZnSe thin films on the Se-modified Au electrode using electrochemical quartz crystal microgravimetry (EQCM) and voltammetry is described. Corrosion of pre-deposited Se electrodes by illumination at a fixed potential resulted in $Se^{2-}$ species, which was manifest from the EQCM frequency changes. $Se^{2-}$ species generated from the photocorrosion reacted with $Cd^{2+}$ and $Zn^{2+}$ ions in the electrolyte to form CdZnSe films on the Au electrode. The effect of electrolyte composition on the composition and band gap of CdZnSe films was studied in detail. Also, photoelectrochemistry, EDX, Raman spectroscopy were used for the characterization of CdZnSe thin films.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.5
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• pp.551-556
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• 1996

Selenium (Se) apparent absorption and retention in sheep as influenced by diets differing in protein content through soybean meal supplementation was studied. A $3{\times}3$ Latin square design was used with three Japanese Corriedale wethers (45 kg average body weight), three periods, and three dietary treatments. In each period, 7 d dietary adjustment was followed by 5 d total collection of urine and feces. The three dietary treatments were : Diet 1, without soybean meal supplementation (14% crude protein, CP); Diet 2, with 10% soybean meal supplementation (16.5% CP); and Diet 3, with 20% soybean meal supplementation (19% CP). All the diets had a Se supplementation in the form of sodium selenite at 0.2 mg Se/kg dietary DM. The dietary DM intake of the animals was 2% of their body weight. No significant differences were obtained among the three dietary treatments of the Se balance of the animals. However, as percent of Se intake, only urinary Se concentration of Diet 3 was markedly lower (p < 0.05) than the other diets. Fecal Se as percent of Se intake followed the trend of Diet 3> Diet 2 > Diet 1 resulting a Se absorbed as percent of Se intake of 58.9%, 62.3% and 68.2% for Diets 3, 2 and 1, respectively but their differences among each other were insignificant. No significant differences that were observed either on Se retained as percent of intake (Diet 1, 48.2%; Diet 2, 45.2%; Diet 3, 46.0%) or Se retained as percent of Se absorbed (Diet 1, 70.7%; Diet 2, 72.4%; Diet 3, 77.9%). Significant correlation coefficients among the various measures of Se utilization were also observed. Regression analysis showed the following equation: Y = 93.8 - 1.86X (p <0.05, $r^{2}=0.48$), where Y is the Se absorbed as percent of Se intake (%) and X is the dietary protein content (%). This study concludes that Se requirement in sheep is greater when dietary protein content is high.

• 시스템엔지니어링워크숍
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• s.1
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• pp.119-126
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• 2003

After attending the special lecture by Halligan on "The Principles of Systems Engineering" at the 2002 KCOSE workshop, the author tried to collect similar SE principles scanning throughout several SE text books and internet sources. During this process it is found that INCOSE once established a SE-Principles WG and tried to collect SE-principles. They tried to make distinctions among pragmatic, mathematical, and philosophical principles. The result of this effort to collect various SE-principles showed that, including the INCOSE SE-principles WG, most authors seem only succeeded in generating the pragmatic SE-principles but failed in both mathematical and philosophical SE-principles.

• Journal of Practical Agriculture & Fisheries Research
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• v.7 no.1
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• pp.97-108
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• 2005

This study was carried out to determine effects of the feeding length of spent mushroom composts from selenium-enriched mushroom (Se-SMC) on muscular selenium deposition in finishing Hanwoo steers. A total of 30 steers were allotted to an experiment with a 3 × 2 factorial arrangement. Treatments were 2 groups of with and without Se-SMC at three different feeding lengths (2, 4, and 6 months) by body weight (BW). And then dry matter intake, body weight gain, Se concentration and/or content in blood and/or muscle were investigated. Dry matter intake was not affected by feeding length and Se-SMC supplementation. As the feeding length was prolonged, initial and final BW was significantly lowered (p<0.01) with no Se-SMC effect. However, total BW gain was significantly increased (p<0.0001) with increasing feeding length with no effect of Se-SMC. Se-SMC supplementation significantly increased Se concentration in whole blood, but there was no effect on feeding length. Se contents in muscles, especially hind-leg, were significantly increased (p<0.05) as the feeding length was increased. However, there was no difference for Se content between four and six months feeding groups of Se-SMC and also hepatic Se content was not affected by feeding length. On the contrast, hepatic Se content for Se-SMC group within each feeding length was significantly increased (p<0.001) compared with no Se-SMC supplementation. In conclusion, our results suggested that optimum feeding length of Se-SMC as a strategy for the production of Se-fortified beef might be approximately 4 months.

• Journal of the Korean Ceramic Society
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• v.32 no.2
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• pp.239-247
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• 1995

Chalcogenide glasses with compositions of Ge10Se90-xTex(X=0~50 at.%) were prepared in order to investigate the effects of Te substitution on the transmission characteristics of Ge-Se glasses in the 8~12 ${\mu}{\textrm}{m}$ wavelength region. Absorption coefficients were observed to decrease with Te addition, indicating the improved transmission capabilities of Ge-Se-Te glasses as compared to binary Ge-Se glasses. XRD analysis of crystallized glasses suggested the formation of weaker Se-Te and/or Te-Te bonds with addition of Te substituting for Se in stronger Se-Se bonds. Incorporation of Te in excess of 20at% resulted in the formation of hexagonal Te phases when crystallized. It is speculated that the presence of Te-Te bonds with highly metallic bond character resulted in the enhanced crystallization tendencies of glasses. Fromation of Te-rich chains through gradual replacement of Se-Se with Se-Te and/or Te-Te bonds was further supported by decreases in glass transition and crystallization temperatures.

• Journal of the Korean institute of surface engineering
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• v.42 no.2
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• pp.63-67
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• 2009

CdSe is one of the composite semiconductor materials used in hybrid solar cell. CdSe nanorods were fabricated using electrochemical deposition in anodic aluminum oxide (AAO) template. CdSe were deposited from $CdSO_4$ and $H_2SeO_3$ dissolved aqueous solution by direct current electrochemical deposition. Uniformity of CdSe nanorods were dependent on the diameter and the height of holes in AAO. The current density, current mode, bath composition and temperature were controlled to obtained 1:1 atomic composition of CdSe. CdSe electroplating in AAO is bottom-up filling so we applied direct current is better than others for good uniformity of CdSe nanorods. The optimum conditions to obtain 1:1 atomic composition of CdSe nanorods are direct current $10\;mA/cm^2$, 0.25 M $CdSO_4$-5 mM $H_2SeO_3$ electrolytes at room temperature.

• Journal of Practical Agriculture & Fisheries Research
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• v.6 no.1
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• pp.90-101
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• 2004

Se is essential for a number of enzymes that perform important metabolic functions necessary for good health. However, people in many countries do not appear to consume adequate amounts of Se to support the maximal expression of the selenoproteins and Se retention in the body of animals and humans is dependent on the ingested Se source such as organic and inorganic Se. Therefore, this review was discussed to explore metabolic characterization regarding intestinal absorption, bioavailability and selenoprotein synthesis according to animal species such as monogastrics including human beings and ruminants. Generally, organic Se provided to animals is more effective than inorganic Se in body retention for the animal owing to the difference of manner for intestinal absorption. But, Se absorption in ruminants depending on its chemical form still remained questioned by several microbial actions and feeding regimen in the rumen. And Se absorbed through small intestine is utilized for the synthesis of selenoproteins and/or retained as selenoamino acids in the body. Retained Se in the body may be recycled to synthesize selenoproteins as lacked of dietary Se. In conclusion, desirable forms of Se ingestion in the animal may be useful for Se fortification in animal products as well as well being for humans and animals.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.365-370
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• 2009

An experiment was conducted to evaluate the effect of different levels of supplemental selenomethionine (Se-Met) on growth performance and serum antioxidant status in Taihang Black goats. Fifty 16-week-old goats with an average body weight of 12.5${\pm}$0.5 kg were randomly assigned to five treatments fed a basal diet (0.049 mg Se/kg DM) supplemented with 0 (control), 0.10, 0.30, 0.50 and 1.00 mg of Se/kg DM (form Se-Met) for 80 days. Average daily gain and feed efficiency were higher (p<0.05) in the groups supplemented with 0.30 to 0.50 mg Se/kg DM compared with the control group. However, Se-Met supplementation had no influence on average daily feed intake (p>0.05). Se-Met supplementation significantly increased (p<0.01) the activity of glutathione peroxidase enzymes (GSH-Px) and superoxide dismutase (SOD) in serum. The group supplemented with 0.50 mg Se/kg DM had the highest activity of GSH-Px compared with other groups (p<0.05). Serum SOD activity was higher (p<0.05) in goats supplemented with both 0.30 and 0.50 mg Se/kg DM than in control goats and goats supplemented with 1.00 mg Se/kg DM. Serum glutathione-S-transferase (GST) activity and malondialdehyde (MDA) concentration were significantly decreased (p<0.05) in goats supplemented with 0.30, 0.50 and 1.00 mg Se/kg DM compared with control values. These results indicated that Se-Met supplementation markedly improved the antioxidant status in goats. Blood Se concentration increased linearly (p<0.001) and quadratically (p<0.001) as the level of supplemental Se-Met increased. The concentration of Se in the control diet (0.049 mg Se/kg DM) did not satisfy the Se requirement in goats as indicated by reduced growth rate, feed efficiency, activities of GSH-Px and SOD in serum, and blood Se concentrations. In conclusion, it is recommended that 0.30 to 0.50 mg of Se/kg DM from Se-Met (total diet Se of 0.349 to 0.549 mg/kg DM) be supplied in the diet of Taihang Black goats to enhance growth performance and improve antioxidant status.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.5
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• pp.189-197
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• 2006

A stoichiometric mixture of evaporating materials for $AgGaSe_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $AgGaSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy(HWE) system. The source and substrate temperatures were $630^{\circ}C\;and\;420^{\circ}C$, respectively. The temperature dependence of the energy band gap of the $AgGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.9501eV-(8.79x10^{-4}eV/K)T^2(T+250K)$. After the as-grown $AgGaSe_2$ single crystal thin films was annealed in Ag-, Se-, and Ga-atmospheres, the origin of point defects of $AgGaSe_2$ single crystal thin films has been investigated by the photoluminescence (PL) at 10K. The native defects of $V_{Ag},\;V_{Se},\;Ag_{int},\;and\;Se_{int}$ obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Ag-atmosphere converted $AgGaSe_2$ single crystal thin films to an optical p-type. Also, we confirmed that Ga in $AgGaSe_2$/GaAs did not form the native defects because Ga in $AgGaSe_2$ single crystal thin films existed in the form of stable bonds.