• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1050-1053
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• 2002

This paper presents metal structure that is fabricated using UV-LIGA process with PMER N-CA3000. In order to fabricate metal structure with high aspect ratio, the systematic optimization method was adopted and then the structure of $36{\mu}m$ thick mold with aspect ratio 7:1 (trench) and $32{\mu}m$ thick nickel structure was obtained. This structure is applied to the fabrication of optical switch.

• Journal of Nutrition and Health
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• 제30권5호
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• pp.529-539
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• 1997

The present study was to formulate a computer program to provide a menu based on a food preference survey of families in urban areas. A food preference survey was conducted by individual direct interviews of infants, children and old people in this study. In case other's food preferences were available, food menus considering all age groups could be made. Database III PLUS package was utilized for this study. The dBASE was loaded with a food compostion table of 339 different food items, along with data for amino acids and fatty acids for 171 and 43 food items respectively. Food preference, unit of food, and recommended dietary allowances were also incloded. This meun program system calculates nutrients in selected foods, and menu assessment was composed of several factors inculding energy ratio of carbohydrate : protein : fat, amino acid score, limiting amino acid, polyunsaturated fatty acid/saturated fatty acid(JP/S) ratio and Ca/P ratio.

• 한국세라믹학회지
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• 제34권5호
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• pp.491-499
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• 1997

High flexible lightweight composites containing tobermorite as a main mineral is produced using various amorphous silicates, lime, cement and fibers. Here, Mechanical properties of the composites were studied by observing microstructures of hydrates and fibers. Amorphous silicates having better hydraulicity retarded the crystallization of tobermorite due to better formation of C-S-H gel in water bath curing, but, difficult conversion from C-S-H gel to tobermorite in hydrothermal reaction. In the low molar ratio of CaO/SiO2 (0.67), faster crystalization was observed dued to more impurities such as Al2O3 alkali, resulting in improving mechanical properties due to small crystal size and many contact points. It was identified that a lot of calcium silicate hydates formed at surface of pulps increase bonding strength and the crack-resistance of matrix in the composites, but decrease hardness and compressive strength. The choice of amorpous silicates having better hydraulicity, low CaO/SiO2 adding each fibers bellow about 5% in the raw mixs and lower molding pressure should be needed at improve mechanical properties of composites.

• 한국세라믹학회지
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• 제15권4호
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• pp.199-204
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• 1978

In the present investigation, refined alumina obtained from alunite locally available was used as a aluminous source to synthesize monocalcium aluminate $(CA)_3$ the major mineral constituent of alumina cement. The influence of $SiO_2$ and $Fe_2O_3$ contents on the formation of monocalcium aluminate was studied by X-ray diffraction analysis mainly. About 0.8-1.0 of $Al_2O_3/C_3O$ mol ratio and less than 4 percent of $SiO_2$ were desirable for the effective formation of CA. The small amount of alkali and sulphur contents contained in refined alumina from alunite as the impurities were affected to form $C_4A_3S$ and $C_3S_2$, disadvantageous compounds for the alumina cement, therefore the impurities should be restricted in minimum content as possible.

• 한국물환경학회지
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• 제25권6호
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• pp.916-921
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• 2009

This study was aimed to both enhance the fluoride removal and to reduce the phosphorus removal in treating semiconductor wastewater using $Ca(OH)_2$ at low pH so as to facilitate struvite crystallization reaction. The struvite crystallization could be introduced after fluoride removal by retaining the phosphorus source. As the results, the method applied in this study achieved high fluoride removal efficiency (about 91%) with retardation of phosphorus removal at pH 4, compared to conventional methods where the removal of fluoride and phosphorus were done at pH 11. Therefore, the fluoride removal at low pH would contribute to the enhancement of nitrogen and phosphorus removals in a consecutive struvite crystallization reactor. Treatment of semiconductor wastewater at low pH using $Ca(OH)_2$ also had lower (about 20%) water content of precipitated sludge compared to conventional method. As the molar ratio of Ca to F increased the removal efficiencies of fluoride and phosphorus increased. Although the amount of seed dosage didn't affect the removal of fluoride and phosphorus, its increase reduced the water content of precipitated matter. Finally, considering consecutive struvite reaction, the optimum condition for the removal of fluoride and phosphorus was as follow: pH: 4, the molar ratio of Ca:F: 1:1.

• 생약학회지
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• 제22권3호
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• pp.171-182
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• 1991

Several experiments were carried for the purpose of establishing the basis for the quality evaluation of deer horn. Deer horn originated from China, New Zealand, Soviet and Alaska were used as objectives and some constituents involved in deer horn were assayed and compared with one another. Five kinds of trace elements including Ca and Fe were determined by atomic absorbance spectroscopy. The more the region came down from the top of the deer horn, the more the ratio of Ca to Fe content (Ca/Fe) was increased. The same increasing tendancy was observed in the case of ash content. Gangliosides were isolated from deer horn by alumina column chromatography and identified by TLC using gangliosides Type II obtained from bovine brain as the standard material. The TLC chromatograms were scanned by dual wavelength TLC scanner, then those TLC profiles were compared. Deer horn from China and New Zealand were analogous but those from Soviet and Alaska were each distinguished in their TLC profiles.

• 대한전자공학회논문지
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• 제22권6호
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• pp.34-40
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• 1985

분자선 에퍼택시 (MBE)방법을 이용하여 (100) GaAs웨이퍼 위에 GaAs에퍼충을 성장시켜 성장된 충에 대한 여러가지 특성을 조사 ·분석하였다. 분자선 에피택시 방법을 이용하여 CaAs에퍼층을 만들 때에는 기판온도와 As와 Ca의 분자선 밀도비 (As/Ga)가 가장 큰 영향을 미친다. 본 실험에서는 좋은 표면상태를 얻기 위해 480℃∼650℃로 유지시키고 As cell의 온도를 230℃, Ga eel함 온도를 917℃로 고정시켜 As와 Ga의 분자선 밀도비를 5∼10 이상으로 유지시켰다. 제작된 GaAs에피층의 표면상태를 SIMS (Seconde,y ion Mass ipectoscopy), AES(Auger Electron Spectroscopy) , SEM (Scanning Elect.on Mic,oscopy) , RHEED (Reflection High Energy Electron Diffraction) 등으로 조사한 결과 기판온도가 540℃일 때 가장 좋은 표면상태를 얻을 수 있었다. 또한 RH-EED관찰 결과 As 안정화된 표면을 관측할 수 있었으며 SIMS로 depth-Profile을 해 본 곁과, Ca 보다 As가 불안정함을 알았다. 또한 반선 회절 검사결과에서 기판온도가 520℃일때와 540℃일때 (400), (200)면에 단결정이 형성되었음을 알 수 있었다.

• Nutrition Research and Practice
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• 제9권5호
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• pp.539-546
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• 2015

BACKGROUND/OBJECTIVES: Women's bone health status is closely related with environmental factors and lifestyle factors. The purpose of this study is to evaluate the dietary risks of osteoporosis and osteopenia for Korean postmenopausal women. SUBJECTS/METHODS: The data from 1,433 subjects from the 2010 KNHANES were used and divided into three groups: normal, osteopenia, and osteoporosis group using bone mineral density (BMD). Nutrient intakes and food intake frequency were evaluated. Logistic regression analysis was applied to determine the odds ratios for osteoporosis and osteopenia. RESULTS: The RNI percentage of each nutrient and food intake frequency from 12 food groups decreased as bone mineral density status deteriorated. Risk for osteoporosis of low calcium (Ca) intake, under the EAR, showed an odds ratio of 2.13(95% CI; 1.26-3.61, P < 0.05). Higher intake frequency showed preventive effect from osteoporosis compared to lower intake frequency in such food group as dairy products (ORs 0.40, CI 0.21-0.75), beans (ORs 0.49, CI 0.29-0.83), seaweeds (ORs 0.55, CI 0.32-0.94), fish (ORs 0.56, CI 0.32-0.98), and fruits (ORs 0.42, CI 0.23-0.79) after adjusting for age. CONCLUSION: To prevent osteoporosis in later life, sufficient Ca intake and more frequent intakes of foods containing Ca such as dairy products, beans, fish, seaweeds, and fruits, which help in Ca absorption, should be stressed for Korean postmenopausal women.

• 동아시아식생활학회지
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• 제19권6호
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• pp.869-881
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• 2009

The purpose of this study was to investigate the food habits, dietary intakes and GTTs (glucose tolerance tests) of female college students according to BMI in the Kyunggido area. Questionnaire surveys, 24 hr dietary recalls, and GTTs were conducted with 108 students (36 under-weight students, 42 normal weight students, and 30 over-weight students). The results were as follows: The under wt. and over wt. groups had lower frequencies of eating breakfast but higher frequencies of eating lunch than the normal wt. group. The ratio of students having dinner everyday was low in the order of under wt. > normal wt. > over wt.. The over wt. group skipped breakfast mainly due to lack of time and the need to get to school, and the under wt. group had a high ratio (48.1%) of lunch skipper as a result of having brunch. The over wt. subjects had poor habits of eating fast and overeating, but the under wt. students ate their meals slowly. The under wt. group had a high ratio of students who ate snacks and fast-food. All subjects wanted to immediately improve their poor habit of overeating. Plant oil, animal Fe, and vitamin E intakes were lower in the under wt. group than in the other groups. For the GTT, the over wt. students had significantly lower blood glucose levels after 30 min. than the other groups. BMI was negatively correlated with blood glucose level after 30 min, but positively correlated with crude fiber, ash, Ca, plant Ca, P, animal Fe, Na, K, $\beta$-carotene, vitamin $B_6$, niacin, and vitamin E.

• Korean Chemical Engineering Research
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• 제47권4호
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• pp.512-517
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• 2009

순산소 연소에서 $SO_2$ 농도는 배가스의 재순환으로 인해 기존의 공기연소에 비해 3배 이상 높게 나타나고, $CO_2$ 농도와 $SO_2$ 농도가 높기 때문에 탈황현상이 기존의 공기 연소와는 다르게 나타난다. 본 연구에서는 순산소 연소조건에서 로내탈황 특성을 알아보기 위해 Drop Tube Furnace(DTF)를 이용하여, 반응온도, 유입 $SO_2$ 농도 그리고 Ca/S 비 등의 운전변수에 따른 $SO_2$ 제거효율을 측정하였으며 수분의 영향에 대해서도 알아보았다. 반응온도, 유입 $SO_2$ 농도 그리고 Ca/S 비가 증가함에 따라 $SO_2$ 제거효율은 증가하였고 유입가스 내 수분이 존재할 경우 $SO_2$ 제거효율은 약 4~6% 증가하는 것으로 나타났다.