• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.154-154
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• 2008

Although the screen printing technology using photosensitive carbon nanotube (CNT) paste has many advantages such as low cost, simple process, uniform emission, and capability of mass production, the CNT paste needs to be improved further in CNT dispersion, printability, adhesion, electrical conductivity, population of CNT emitters, etc. Ball milling has been frequently employed to prepare the CNT paste as ball milling can mix its ingredients very well and easily cut the long, entangled CNTs. This study carried out a parametric approach to fabricating the CNT paste in terms of low-energy ball milling and a paste composition. Field emission properties of the CNT paste was characterized with CNT dispersion and electrical conductivity which were measured by a UV-Vis spectrophotometer and a 4-point probe method, respectively. Main variables in formulating the CNT paste include a length of milling time, and amounts of CNTs and conductive inorganic fillers. In particular, we varied not only the contents of conductive fillers but also used two different sizes of filler particles of ${\mu}m$ and nm ranges. Among many variations of conductive fillers, the best field emission characteristics occurred at the 5 wt% fillers with the mixing ratio of 3:1 for ${\mu}m$-and nm-sizes. The amount and size of fillers has a great effect on the morphology, processing stability, and field emission characteristics of CNT emitter dots. The addition a small amount of nm-size fillers considerably improved the field emission characteristics of the photosensitive CNT paste.

• The Korean Journal of Ecology
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• 제17권2호
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• pp.113-119
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• 1994

Vertical and horizontal distribution and seasonal changes of fine roots as well as inorganic nitrogen content in soil were determined in Quercus mongolica and Quercus acutissima stands in Mt. Taemosan, Seoul. The vertical distribution of fine rooth phytomass showed a power-functional decrease as descending soil depth. Fine root phytomass was 170 g $DM/m^2$(46%) and 225 g $DM/m^2$(47%) in top soil of 5 cm depth, and 370 g $DM/m^2$ and 480 g $DM/m^2$ from soil surface to 50 cm depth in Q. mongolica and Q. acutissima stands, respectively. Fine roots in relation to the distance from the nearest tree were evenly distributed horizontally in both stands. Fine roots phytomass in top soil of 5 cm depth reached a peak in June, and thereafter decreased gradually in both stands. Patterns of seasonal changes in fine root phytomass were closely related to inorganic nitrogen and moisture content.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.417-418
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• 2009

해안 및 매립지 구조물은 염화물의 침투로 인해 매입된 철근의 피막파괴로 철근부식이 일어나 콘크리트 구조체에 열화가 급속하게 진행되기 때문에 앞으로의 해안 구조물의 수밀성, 내염해성을 필요로 한다. 따라서 본 연구에서는 내염해성 개선에 효과적인 액상형태의 Si/Al 복합 무기염을 모르타르에 적용하여 시간경과(7, 14, 28, 56일)에 따른 내염해특성을 파악하고자 하였다.

• 한국전기전자재료학회논문지
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• 제29권12호
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• pp.737-749
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• 2016

Recently perovskite materials with much cheaper cost and marvellous optoelectronic properties have been studied for next generation LED display devices overseas. Technology development trends of inorganic $CsPbX_3$(X=halogen) based LEDs (PeLEDs) with assumed high stability were investigated on literature worldwide. It was found that syntheses methods of these nanocrystals (NCs, mainly quantum dots, QDs) made great progress. A new room temperature synthesis method showed outstanding PL (photoluminescence) properties such as high quantum yield (QY), narrow emission width, storage stability comparable with, or often exceeding those of conventional hot injection method and CdSe@ZnS type inorganic colloidal QDs. PeLEDs with shell layers might be more promising, indicating urgent real research start of this solution processing technology for small businesses in Korea.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.141-144
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• 2004

Nowadays, there has been substantial interest in whether there is an association between electromagnetic field exposure and living environment. It is increased the demand that electromagnetic wave environment and its countermeasure. In the present study, we has applied the electromagnetic absorbent inorganic paint of 'I' corporations, and measured electromagnetic waves generated in new apartment before occupancy using the standard field electromagnetic wave generating device we developed. The measurement before occupancy was $100\~131V/m$, but the measurement after occupancy was $6.9\~8.0V/m$ less than 10V/m, the comprehensive electromagnetic wave limit allowed by TCO in Sweden. The implication is that domestic apartment are exposed to extremely poor electromagnetic wave environment. Nevertheless, there have been neither serious efforts to overcome this problem, nor its alternatives and related standards. Therefore, it is necessary to continue research of related fields to establish standards and plans to improve the situation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.853-856
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• 2006

It is known that cement production not only consumes large amount of energy but also contributes substantially to the green house gas emission. Therefore, there is a demand to develope a new technology to produce energy efficient and environmental conscious cements. The most recent, wood wool ceramic board is being applied in various building material field, for example thermal insulating and acoustic absorption material. This paper focused on improvement of the physical properties for wood wool ceramic board applied inorganic polymer binder. As the result of this experiment, what we could obtain better wood wool ceramic board's properties such as density, water contests, water resistance and band strength, was 0.46, $10{\sim}12%$, 1.9% and $40kgf/cm^2$. This result can be applicable to commercial wood wool ceramic board.

• Asian-Australasian Journal of Animal Sciences
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• 제20권2호
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• pp.229-236
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• 2007

This study was conducted to determine effects of different selenium (Se) sources on performance, carcass characteristics, blood measures (whole blood Se concentration and plasma glutathione peroxidase (GSH-Px) activity), and Se concentrations in tissues of finishing Hanwoo steers (Korean native steers). Twenty finishing Hanwoo steers (average body weight=536${\pm}$23.4 kg, average age=approximately 20 months) were allotted to treatments in four groups of five steers per pen for 16 weeks preceding slaughter. Treatments were control (CON), spent mushroom composts from Se-enriched mushrooms (Se-SMC), selenized yeast (Se-Y), and sodium selenite (SS). Dietary Se levels of all treatments except CON were 0.9 mg Se/kg on the dry matter basis. Body weight was measured at the first and final day of trial, and blood samples were collected to analyze whole blood Se concentration and plasma GSH-Px activity at 2, 4, 8, and 16 weeks. At the end of trial, steers were slaughtered to collect muscle and liver samples for their Se analyses, and carcass data were recorded. In terms of dry matter intake, body weight gain and carcass characteristics, no significant differences among treatments were observed. Whole blood Se concentrations were significantly higher (p<0.05) for Se-SMC and Se-Y treatments than for CON at each collection period, with no significant difference between SS and CON. For weeks 2 and 8, there was no significant difference for whole blood Se concentration between Se-SMC and Se-Y, but for weeks 4 and 16, Se-Y treatments were significantly higher (p<0.05) than Se-SMC. No differences were observed for plasma GSH-Px activity between Se-SMC and Se-Y. The Se concentrations in hind leg and liver were significantly different among treatments (p<0.05) and those in both tissues ranked the greatest in Se-Y, followed by Se-SMC, SS, and CON treatments. However, tissue Se concentration for SS was not different from that for CON. These results showed that feeding organic Se sources such as Se-SMC and Se-Y enhanced Se concentration in tissues, while SS, the most common supplement of inorganic Se, was inefficient in Se deposition. Even though Se-Y had a higher Se concentration in tissues than Se-SMC, replacing Se-Y with Se-SMC in diets of beef steers would be an inexpensive way to increase Se concentration in beef.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3817-3824
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• 2013

Various separation modes in HPLC, such as anion exchange (AE), reversed-phase (RP), and affinity (AF) chromatography were examined for the separation of selenium species in human blood serum and urine. While RP- and AE-HPLC were mainly used for the separation of small molecular selenium species, double column AF-HPLC achieved the separation of selenoproteins in blood serum efficiently. Further, the effluent of AF-HPLC was enzymatically hydrolyzed and then analyzed with RP HPLC for selenoamino acid study. The versatility of the hybrid technique makes the in-depth study of selenium species possible. For quantification, post column isotope dilution (ID) with $^{78}Se$ spike was performed. ORC ICP/MS (octapole reaction cell inductively coupled plasma/mass spectrometry) was used with 4 mL $min^{-1}$ Hydrogen as reaction gas. In urine sample, inorganic selenium and SeCys were identified. In blood serum, selenoproteins GPx, SelP and SeAlb were detected and quantified. The concentration for GPx, SelP and SeAlb was $22.8{\pm}3.4\;ng\;g^{-1}$, $45.2{\pm}1.7\;ng\;g^{-1}$, and $16.1{\pm}2.2\;ng\;g^{-1}$, respectively when $^{80}Se/^{78}Se$ was used. The sum of these selenoproteins ($84.1{\pm}4.4\;ng\;g^{-1}$) agrees well with the total selenium concentration measured with the ID method of $87.0{\pm}3.0\;ng\;g^{-1}$. Enzymatic hydrolysis of each selenium proteins revealed that SeCys is the major amino acid for all three proteins and SeMet is contained in SeAlb only.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.55-60
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• 2006

This experiment was conducted to investigate the effects of selenium (Se) sources and levels on growth performance, nutrient digestibility and Se retention in growing-finishing pigs. A total of 56 crossbred pigs ([$Landrace{\times}Yorkshire$]${\times}$Large White) with average $28.5{\pm}0.2kg$ BW were allotted to 7 treatments on the basis of sex and weight in two replicates and four pigs per pen. A $2{\times}3$ factorial arrangement of treatments was used in a randomized complete block (RCB) design. Two sources of Se (selenite Se or Se-enriched yeast) were added at 0.1, 0.3 and 0.5 mg/kg to each treatment diet. A basal diet without Se supplementation was the seventh treatment group. Three pigs per treatment were randomly selected and samples of loin, liver, pancreas and a kidney were collected, frozen and later analyzed for Se. The digestibility trial was conducted to evaluate the apparent absorption and retention of Se and availability of other nutrients. Growth performance was not affected by dietary sources and levels of Se. No growth retardation was observed in the 0.5 mg/kg dietary Se treatment group regardless of Se sources. The Se concentration of serum in Se supplemented groups was increased compared with the control group (p<0.01). During the growing and finishing phase, Se in serum was clearly increased when organic Se was provided (p<0.01). Interaction of Se source ${\times}$ Se level was observed in Se concentration of loin, liver and pancreas of the pigs at the end of experiment. Selenium retention in the liver, kidney, pancreas and loin of pigs was increased as dietary Se level increased and was higher when pigs were fed organic Se resulting in an interaction response (p<0.01). Nutrient digestibilities were not affected by dietary Se sources or levels. No dietary Se source ${\times}$ Se level interaction was observed in nutrient digestibility. The results from this experiment indicated that dietary Se sources and levels affected the distribution of Se in the body of growing-finishing pigs. Organic source of Se, such as Se-enriched yeast resulted in higher serum and tissue Se concentration compared to inorganic form, while no beneficial effects on nutrient digestibility were observed from dietary Se supplementation in growing-finishing pigs.

• 현장농수산연구지
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• 제6권1호
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• pp.102-115
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• 2004

본 연구는 셀레늄강화버섯생산 후 대량으로 폐기되는 버섯 폐배지를 가축사료로 이용하기 위해 발효사료를 제조하고, 발효 기간동안 발효미생물에 의한 무기셀레늄을 유기셀레늄으로의 전환을 강화하기 위해 발효사료 내 존재하는 유기셀레늄 비율을 조사하였다. 발효사료의 처리구는 일반버섯 폐배지와 셀레늄강화버섯 폐배지를 조합하여 발효사료 내 셈레늄농도가 0.06, 0.54, 1.26 및 1.86ppm이었다. 그리고 발효기에서 48시간 동안 발효시켰으며, 발효시간(0, 12, 24, 48시간)에 따른 pH, 유기셀레늄 비율, 유기설레늄 함량 및 무기셀레늄 함량을 조사하였다. 발효사료 내 셀레늄함량이 증가함에 따라 0시간의 pH는 일반버섯 폐배지로만 구성된 0.06ppm의 4.63보다 유의하게 직선적으로 증가하였고, 1.86ppm에서 가장 높은 값(6.35)을 나타내었다(p<0.0001). 발효 12시간 이후에는 대조군에 비하여 셀레늄강화 버섯 폐배지를 함유하는 처리군에서 pH가 유의하게 감소하였으나, 처리군들 간에는 유의한 차이가 나타나지 않았다. 셈레늄 농도별 발효사료의 무기셈레늄, 유기셈레늄 함량 및 유기셈레늄 비율은 처리구간에 유의한 차이를 나타내었다(p<0.001). 발효시간에 따른 처리군의 유기셀레늄 비율은 0.54ppm에서 발효 24시간까지 유의하게 증가하였고, 1.26ppm에서는 발효 12시간이후에는 유의한 증가가 나타나지 않았으며, 1.86ppm에서는 유의한 차이가 나타나지 않았다. 그리고 일반 페배지로만 구성된 0.06ppm의 발효사료에서는 무기셀레늄이 검출되지 않았고, 셀레늄강화버섯 폐배지를 함유하는 발효사료(0.54ppm, 1.26ppm, 1.86ppm)는 발효 48시간에 약 70%의 유기셀레늄을 함유하였다. 이상의 결과로부터, 발효사료를 통한 유기셀레늄의 강화는 발효종료 후 폐배지 내 유기셀레늄 비율이 약 70%로 높게 나타나 반추가축에 대한 셀레늄사료자원으로 유용할 것으로 생각된다.