• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.304-304
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• 2007

고주파 모률에서 사용되는 기판소재는 저유전율과 낮은 loss 특성을 요구함으로 지속적인 연구를 필요로 한다. 지금까지의 ceramic/glass composite 에서 주로 사용된 ceramic filler는 Al2O3로 낮은 유전률을 구현에 한계가 있었다. Cordierite는 낮은 유전율 (${\varepsilon}_r$ < 4)을 나타내는 filler로서 그 가능성이 높지만 아직까지 보고된 결과들이 미흡한 실정이다. 따라서 본 연구에서는 cordierite filler와 SiO2-B2O3-Al2O3-RO (R : Zn, Sr, Ba, Ca)계의 glass를 혼합하여 LTCC용 기판소재로서의 가능성을 확인하고자 저온 동시소성이 가능한 소결온도인 $850^{\circ}C{\sim}1.000^{\circ}C$ 사이에서 소재의 소결실험을 진행하였다. 소결온도에 따른 상변화, 유전특성을 확인한 결과 filler로 사용된 cordierite상만이 관찰 되었으며 소결조건에 따라 5.0~5.5의 낮은 유전율과 1.000~1,500의 Q를 나타내는 것을 확인 하였다.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3796-3803
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• 2024

By employing the melt-quenching technique, the ZnO-SrO-B₂O₃-PbO (ZSBP) glasses have been successfully fabricated. The derivative of Absorption Spectra Fitting (DASF) method was used to study the energy band gap (E_g) of the glasses which decreases from 3.57 eV to 3.39 eV. The structural properties have been studied using the Raman spectroscopy. The glass transition temperature (T_g) decreases with increase in concentration of the lead oxide. The current study examines the radiation shielding properties at 30.80-444 keV. The addition of PbO to the glasses resulted in a proportionate increase in the mass attenuation coefficient (MAC), suggesting a diminishing tendency in radiation transmission. At 30.80 keV, the MAC values are extremely high and range from 18.06 to 21.11 cm²/g. As density rises, the half value layer (HVL) decreases. In addition, the average HVL (${\overline{HVL}}$) decreases. The glass thickness required to reduce the radiation intensity to 90 %, 50 %, 25 %, and 10 % of its initial value is investigated at an energy of 35.80 keV. The T90 %, T50 %, T25 %, and T10 % values are 0.0020, 0.0132, 0.0264, and 0.0439 cm, respectively. The results suggest that a greater thickness of the radiation barrier is necessary to attain the necessary degree of attenuation.

• Journal of Environmental Impact Assessment
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• v.13 no.6
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• pp.277-284
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• 2004

The chemical composition and properties of soil were determined at selected sites, such as Loess plateau, Gobi and sand deserts in northern China, where most dust storms occur. Although the transport of this sort of dust storms to Korean peninsula is a well-documented phenomenon, there is not enough information about the very source regions. In this reason, this study tried to measure the chemical composition, including soil elements, anthropogenic elements and ions for soil samples so that certain properties of some major source regions of Asian Dust can be provided. Furthermore, the results are classified into four types of soil like Loess, Loess & sand, Gobi, and sand in order to identify the characteristics and difference among the types. $(X/Al)_{crust}$ values for each soil type were also calculated in this study and compared with those of other references including Asian Dust material(ADM). The results indicated that Ca contribution was higher than Al in all the soil types of this study including ADM and, compared with the values of urban area, contribution of anthropogenic elements such as Cr, Pb, Zn was quite low. However, it must be noted that there is such a variation in the result of soil composition, but it is also certain that the very source region soil composition resolved from this study could support the enhanced study on Asian Dust phenomenon in Korea.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.114-114
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• 1995

이 연구에서는 혈전증 치료에 사용되는 혈전 응해제를 국내 독사독으로부터 개발하기 위한 실험을 실시하였다. 그 내용을 요약하면 다음과 같다. 국내에 서식하는 독사인 Agkistrodon blomoffi brevicaudus, Agkistrodon caliginosus와 Agkistrodon saxatilis에서 각각 사독을 채취하여 fibrin plate 방법으로 fibrin 분해능을 조사하여 Agkistrodon blomoffi brevicaudus의 독이 분해능이 가장 우수함을 밝혔다. 이와 같은 사실에 기초하여 A. blomoffi brevicaudus의 독으로부터 p-Aminobenzamidine affinity chromatography와 DEAE ion-exchange chromatography를 이용하여 분자량이 50.8 kDa인 황성 단백질을 정제하였다. 위에서와 같은 방법으로 정제한 단백질은 fibrin 분해능이 우수하고 fibrinogen의 ${\gamma}$ chain은 분해하지 않으나 B$\beta$ chain을 $A\alpha$ chain에 비하여 보다 선택적으로 분해하는 단백분해 효소임을 증명하였다. 이 정제 효소의 Fibrin에 대한 분해능은 266$\mu\textrm{g}$/${\mu}\ell$의 농도에서 Plasmin 1.0 unit (=3.0 WHO unit)보다 높게 나타났다. 정제된 효소는 chromogenic substrate인 N-Benzoyl-Phe-Val-Arg-pNA와 N-p-Tosyl- Gly-Pro-Arg-pNA의 arginine carboxyl side를 분해하고 pH 7.5에서 최대 활성을 보이며, Vmax는 5.46 umo1/1ㆍmin이고, Km 값은 0.20mM이며, 그리고 Cu$^{2+}$, $Zn^{2+}$, soybean trypsin inhibtor에 의해 25～50% 정도, serine proteinase inhibitor인 phenylmethylsulfonyl floride에 의해 80%정도 활성이 억제되는 특성이 있음을 규명하였다.

• Journal of Microbiology
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• v.45 no.5
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• pp.402-408
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• 2007

A strain producing a potent protease was isolated from turban shell. The strain was identified as Bacillus sp. S17110 based on phylogenetic analysis. The enzyme was purified from culture supernatant of Bacillus sp. S17110 to homogeneity by ammonium sulfate precipitation, SP-Sepharose, and DEAE-Sepharose anion exchange chromatography. Protease activity of the purified protein against casein was found to be stable at pH 7 to pH 10 and around $50^{\circ}C$. Approximately 70% of proteolytic activity of the enzyme was detected either in the presence of 100 mM SDS or Tween 20. The enzyme activity was enhanced in the presence of $Ca^{2+},\;Zn^{2+},\;Mg^{2+}$, but was inhibited by EDTA, indicating that it requires metal for its activity. The purified enzyme was found to be a monomeric protein with a molecular mass of 75 kDa, as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography. The purified enzyme was analyzed through peptide fingerprint mass spectra generated from matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) and a BLAST search, and identified as immune inhibitor A (inhA) deduced from nucleotide sequence of B. cereus G9241. Since InhA was identified as protease that cleave antibacterial proteins found in insect, inhA-like protease purified from Bacillus sp. S17110 might be pathogenic to sea invertebrates.

• Solar Energy
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• v.20 no.2
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• pp.43-54
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• 2000

We prepared and characterized $Cu(In_{1-x}Ga_x)Se_2$(CIGS) films using a elemental co-evaporation method for absorbing layer of high efficiency thin film solar cells. The CIGS films deposited on a soda-lime glass exhibited low resistivity because of higher carrier concentration. Na was accumulated at the CIGS surface and the 0 and Se were also accumulated at the surface, suggesting that oxidation is a driving force of Na accumulation. The structure of CIGS film was modified or a secondary phase was formed in the Cu-poor CIGS bulk films probably due to the incorporation of Na into Cu vacancy sites. As the Ga/(In+Ga) ratio increased, the diffraction peaks of $Cu(In_{1-x}Ga_x)Se_2$ films were shifted to larger angle and splitted, and the grain size of $Cu_{0.91}(In_{1-x}Ga_x)Se_2$ films became smaller. All $Cu_{0.91}(In_{1-x}Ga_x)Se_2$ films showed the p-type conductivity regardless of the Ga/(In+Ga) ratio. Ag/n-ZnO/i-ZnO/CdS/$Cu_{0.91}(In_{0.7}Ga_{0.3})Se_2$/Mo solar cells were fabricated. The currently best efficiency in this study was 14.48% for $0.18cm^2$ area ($V_{oc}=581.5mV,\;J_{sc}=34.88mA$, F.F=0.714).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.11 s.242
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• pp.1229-1238
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• 2005

The objective of the present study was to investigate the efficacy of physical water treatment (PWT) technologies using different catalytic materials and an electronic anti-fouling device in the mitigation of mineral fouling in a once-through flow system with mini-channel heat exchanger. Effects of flow velocity and water hardness on the effectiveness of PWT technologies were experimentally studied. The artificial water hardness varied from 5.0 to 10 mo1/m$^{3}$ as CaCO$_{3}$. For 10 mo1/m$^{3}$ solution, fouling resistance reduced by 13-40$\%$ depending on flow velocity and types of PWT devices. On the other hand, fouling resistance reduced by 21-29$\%$ depending on the PWT devices for 5 mo11m3 solutions. The PWT device using alloy of Cu and Zn as catalyst (CM2) was slightly more effective than the others. SEM photographs of scale produced from the 10 mol/m$^{3}$ solution at 1.0 m/s indicated that calcium carbonate scales without PWT devices were needle-shaped aragonite, which is sticky, dense and difficult to remove. Scales with the PWT devices showed a cluster of spherical or elliptic shape crystals. Both the heat transfer test results and SEM photographs strongly support the efficacy of PWT technologies using catalytic materials and an electronic anti-fouling device in the mitigation of mineral fouling.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.6
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• pp.655-662
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• 2005

Body content bone mined density and nutrient intake status of 129 college women in Daegu area are analyze4 The mean age was 23.1 years. Bone mineral density was measured in their right heel by SONOST-2000 ultrasound bone densitometer, and nutrient intake was assessed by a Questionnaire. Diet intake data were obtained by using a 24 hours recall method to evaluate the subject's usual diet. The average energy, Ca, Ee, Zn and folate intakes were 64.2, 47.5, 54.7, 62.9 and $57.4\%$ of RDA, respectively. Ca/P and Ca/Protein ratio were 0.46 and 6.7, respectively. The mean adequacy ratio(MAR), an index of overall dietary quality wag 0.6. The index of nutritional quality was under 1.0 for protein(0.7), vitamin A(0.9), E(0.7), $B_1(0.8)$, niacin(0.8), $B_6(0.6)$ and phosphorus(0.6). The less the protein and energy intake, the less the bone mineral density(p<0.05). The intakes of protein(p<0.05) and that of phosphorus(p<0.001) were positively correlated with bone quality index(BQI). The calcium intake was positively correlated with Z-score(p<0.05). The phosphorus intake was positively correlated with T-score(p<0.001) and Z-score(p<0.0001). In conclusion, this study indicates that nutrient intake of the college women is considerably lower than the RDA. Also the BQI is lower than standard.

• Food Science and Preservation
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• v.13 no.5
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• pp.655-660
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• 2006

To evaluate the chemical characteristics of organic Korean cabbages, the content of moisture, crude protein, crude lipid, crude ash, dietary fiber, mineral, vitamin C, free sugar, organic acid, chlorophyll and carotenoid were analyzed in organic and nonorganic cabbages. The levels of crude protein, crude lipid, crude ash, soluble dietary fiber, insoluble dietary fiber, minerals(Ca, P, Ee, Mg, S, Zn), ascorbic acid, dehydroascorbic acid, fructose, glucose, sucrose, chlorophyll a, chlorophyll b and carotenoid in organic cabbages were higher than those in nonorganic cabbages. However, the content of moisture, malic acid, citric acid, potassium in organic cabbages were lower than those in nonorganic cabbages.

• Journal of Nutrition and Health
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• v.54 no.1
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• pp.1-9
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• 2021

This review describes the risk factors of the nutrition crisis in coronavirus disease 2019 (COVID-19) infections and suggests precision nutrition against long-term psychological and physiological stress. The mandatory quarantine and the social distancing are associated with an interruption of the lifestyle routine, resulting in psychological (i.e., boredom) and physiological stress. The stress with multiple causes and forms induces over-compensation of energy-dense food, such as sugary comfort food, and is defined as "food craving" because carbohydrates positively affect the psychological stability with serotonin secretion. The consumption of foods that promote an immune response against viral infections (vitamins & minerals; Cu, folate, Fe, Se, Zn, and Vit A, B6, B12, C, and D), reduce inflammatory cytokines (w-3 fatty acids, Vit D, fibers, and Mg), contain antioxidants (beta-carotene, Vit E, C, Se, and phenolics), and sleep-inducing proteins (serotonin, melatonin, and milk products) is essential. In addition, a reduced Vit D deficiency in winter due to less time spent outdoors under quarantine has been reported to be associated with viral infections. The case fatality rate of COVID-19 was significantly dependent on age, sex, race, and underlying health condition. To prevent malnutrition and cachexia in elderly people, weight loss and muscle wasting should be monitored and controlled. Inadequate protein intake, sedentary lifestyle, and inflammation are significant risk factors for sarcopenia. Moreover, relatively high intakes of fat or carbohydrate compared to low protein intake result in abdominal obesity, which is defined as "sarcopenic obesity." Keeping the food-safety guidelines of COVID-19, this study recommends the consumption of fresh and healthy foods and avoiding sugar, fat, salt, alcohol, and commercially frozen foods.