• 한국세라믹학회지
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• 제31권12호
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• pp.1507-1512
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• 1994

High strength cement hardened body was prepared by ordinary portland cement, silica-fume, super-plasticizer and the industrial by-product powder such as tailing, paper sludge ash and granulated slag. These raw materials were mixed and formed with w/c=0.18. The cement hardened body is cured in the autoclave at 18$0^{\circ}C$, 10atm. These admixtures made the compressive strength of all specimens develope by 170~230%. The highest compressive strength could be obtained by 236 MPa when mix composition was 14 wt% of silica-fume and 26 wt% of granulated slag. The compressive strength increased with decreasing the average pore size and the amount of the poe over the size of 50 nm by which the appearance of high compressive strength of the cement hardened body were mainly influenced. In the result, the hydration products were C-S-H, tobermorite and ettringite and it was realized that the reason why the cement hardened body became dense and revealed the higher strength was that those hydrates were formed inside of the pore and filled in it and the unhydrated materials played the role of an inner-filler.

• 한국세라믹학회지
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• 제43권10호
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• pp.626-634
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• 2006

Ceramics manufacturers in the nation produced more than 5000 tons of ceramics wastes a year increasing industrial waste quantity: However, almost no researches were made to reduce environmental pollution and to recycle waste ware. In this study, white ware scraps that were produced at Icheon, Gyeonggi-do were recycled to make use of them as raw materials of ceramics body and to develop new ceramics body that had economic advantages and good quality. The findings showed that the addition of waste ware had limit of 20 wt% considering molding. The addition of waste ware of 20 wt% to white ware lowered baking temperature of the white ware that was added by waste ware of 20 wt% by 30$^{\circ}C$ than existing white ware, and property values were good, for instance, porosity of 3% in average and water absorptivity of 2% in average, and the bending strength recorded more than 800 kgf/$cm^2$ to be high than that of existing white ware being sold in market. The waste ware could be used to produce new ware body and to recycle resources and to solve environmental problems caused by burial and to improve property of ceramics and to save transportation costs as well as baking costs.

• 한국세라믹학회지
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• 제31권12호
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• pp.1467-1474
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• 1994

The effects of the dispersion, drying, and binder burning-out on the green-microstructures of gelcasted alumina were studied. The slip consisting of 55 vol% alumina powder and 5 wt% organic materials was well-dispersed by adding 0.28 wt% polyelectrolyte polymer. Green bodies were dried at >85% relative humidity at room temperature. Green-microstructures were observed to be depended on the heating rate during binder burnout. Constant drying rate was not observed in drying process of gelcasted alumina. Sintered body showed its relative density higher than 99% when it was sintered at 1$600^{\circ}C$ for 2 hours.

• 생명과학회지
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• 제19권8호
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• pp.1093-1103
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• 2009

본 연구는 운동을 하지 않은 20대 초반 여대생을 대상으로 발레운동이 신체조성, 체력 및 골밀도에 미치는 효과를 분석하기 위하여 실험군과 대조군으로 나누어 RAD 발레 프로그램을 12주간 수행한 결과 신체조성에서는 TBF, LBM, %fat가, 체력에서는 AMS, sit-ups, SLJ, 1,200 m R &, W가, 골밀도에서는 GT, WT가 집단 간에 차이가 있었고, 신체부위별 골밀도 분포현황에서 골감소증이 실험군에서 변화가 없었으나, 대조군에서는 GT와 WT에서 3명의 증가를 보였다. 신체조성, 체력 및 골밀도간의 상관관계에서는 체중, TBF, LBM, %fat, BMI, AMS가 높은 정적인 상관을 보였으며, 부위별 골밀도의 상관 관계에서는 요추 골밀도, 대퇴경부, 전체 골밀도에서 높은 정적인 상관을 나타냈다. 이상의 결과를 통하여 RAD 발레프로그램이 신체조성, 체력 및 골밀도에 대한 예방 및 개선에 긍정적인 효과를 미치는 것으로 사료된다. 추후 골밀도를 결정하는 주요 인자로 나이, 체질량지수, 흡연, 운동, 영양소섭취량 이외에도 보다 큰 비중을 차지하는 유전적 소인이 있으므로 이러한 소인을 제시할 수 있는 연구가 더 이루어져야 할 것으로 생각되며, 점차 젊은층으로 확대되는 골감소증 현상에 주목하여, 체계적인 연구가 필요하다.

• Journal of Ginseng Research
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• 제30권3호
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• pp.100-105
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• 2006

Liver and kidney are specific organs which play an active role in biotransformation and detoxification mechanisms. Ant adverse effect of chemicals or heavy metal can cause the delay or fade in these mechanisms. Present study was designed to find out the protective effect of Panax ginseng extract on renal functions altered by mercuric chloride (heavy metal) in albino rat. Fifty albino rats were divided into 10 groups. Five groups for acute study and five groups for sud-acute study viz. control group (Tween 20 and distilled water), mercuric chloride treated group (0.926 mg/kg body wt. for acute and 0.044 mg/kg body wt. for sub-acute group after calculated $LD_{50}$ (9.26 mg/kg body wt.) by probit analysis (Finney, 1971), Panax ginseng extract treated group (10 mg/kg body wt. for acute and sub-acute sets), mercuric chloride treated followed by Panax ginseng extract and Panax ginseng extract followed by mercuric chloride group. All doses were given orally by gavage tube. The result revealed that the serum urea and creatinine significantly increased in mercuric chloride treated group, while significantly decreased (p<0.01) in Panax ginseng extract group after acute and sub-acute treatment. The biochemical estimation is also confirmed by nephropathological aspect. However, the Panax ginseng extract treated followed by mercuric chloride group is more prominent than the mercuric chloride treated followed by Panax ginseng extract group. It can be concluded that Panax ginseng extract had a protective nature on renal functions against mercuric chloride toxicity in albino rats.

• Journal of Animal Science and Technology
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• 제61권5호
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• pp.285-293
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• 2019

The objective of this study was to verify the best mating age of gilts at the first parity. Gilts (n = 86) were divided into nine groups in a factorial arrangement with three Ages (AG1, ${\leq}220d$; AG2, 220 to 240 d; AG3, $240{\leq}d$), and three weights (WT1 ${\leq}140kg$; WT2, 140 to 149 kg; WT3, $150{\leq}kg$). A higher body weight gain in AG2 sows during gestation. Sows in AG2 group showed a higher body weight gain at first parity and backfat gain in the parity 2 and 3 during gestation. A greater insulin-like growth factor-1 (IGF-1) was observed in AG1 sows compared with AG3 sows at weaning in the second parity. Sows in WT1 group showed a significant positive effect on the plasma IGF-1 at breeding and weaning time in parity 2. Sows in AG3 group showed a higher plasma leptin at breeding, farrowing, and weaning in the parity 1, and at farrowing in parity 2. Sows in WT3 group showed a higher plasma leptin at breeding, farrowing, and weaning in the parities 1 and 2. Considering the insignificant longevity results, the most efficient time for gilts insemination can be at 220 d when their body weight is 140 kg or lower.

• 한국재료학회지
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• 제15권10호
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• pp.652-656
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• 2005

The samples were prepared with hydroxyapatite(HAp) powder and Polycaboxylate (P.C/HAp=10, 15, 20, 25, 30, 35 $wt\%$). The hydroxyapatite green body with Polycaboxylate were obtained by compaction and drying at room temperature for 3hrs. The higher mechanical properties were observed in HAp sample with $35 wt\%$ Polycaboxylate. The average compressive ana bending strength in HAp with $35 wt\%$ Polycaboxylate are $302 kgf/cm^2$ and $213 kgf/cm^2$ respectively. This strength is higher compare to that of the cortical bone.

• 한국세라믹학회지
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• 제19권2호
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• pp.95-100
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• 1982

Instead of barium carbonate, domestic barite was used as the flux in manufacturing theinsulating porcelain. To avoid the problems arising from the decomposition of barite in the body during firing, BaO.$Al_2O_3$ was synthesized at $1300^{\circ}C$ for 5 hours. synthetic BaO.$Al_2O_3$ was mixed with other materials such as kaoline, alumina, clay, dolomite. The RO content (CaO. MgO. BaO) of the batches was varied from range of 4 to 14wt. % at 2wt. % - intervals, and firing temperature was varied from 1280 to 140$0^{\circ}C$-at 4$0^{\circ}C$ intervals The properties such as water absorption, bulk density. mechnical strength, specific resistance, and linear shrinkage were measured. The body containing 12 wt.% of RO content showed the satisfactory for the application in the Fixed Carbon Film Resistor.

• 생명과학회지
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• 제20권1호
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• pp.124-132
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• 2010

B시 소재 기숙형특목고 K고교 학생 중에서 %fat이 30% 이상인 비만여고생 32명을 3그룹(운동군 2그룹, 통제군)으로 구분하여 1일 65분, 주 3회, 총 8주간 weight training (WT)과 step box training (SBT)을 조합한 복합운동을 A group은 WT 70-80%$RM{\times}3$ sets+SBT (RPE 11-13)${\times}1$ set로, B group은 70-80%$RM{\times}1$ sets+SBT (RPE 11-13)${\times}3$ set로 실시하여 신체조성(soft lean mass, %fat, WHR), HOMA-IR 및 HbA1c의 변화를 알아보았다. 자료처리는 집단 내는 paired t-test를, 집단 간은 측정 전 후의 변화율(%diff.)을 이용, one-way ANOVA (Duncan test)를 실시하여 다음과 같은 결론을 얻었다. 신체조성에서, 집단 내의 SLM은 운동군은 증가하였으나 통제군은 변화가 없었고, WHR은 A group은 감소하였으나 통제군은 증가하였다. %fat은 운동군 모두에서 감소하였으나 통제군은 증가하였다. 집단 간의 SLM은 A그룹이 B그룹과 통제군보다 더 크게 증가하였고, WHR은 A, B그룹이 통제군보다 더 크게 감소하였고, %fat은 A, B그룹이 통제군보다 더 크게 감소하였다. HOMA-IR은 집단 내에서는 운동군 모두 유의하게 감소하였으나 통제군은 유의하게 증가하였다. 집단 간 비교에서는 A, B그룹이 통제군보다 더 크게 감소하였다. HbA1c는 집단 내에서는 운동군 모두 유의하게 감소하였고 통제군은 변화가 없었다. 집단 간에서는 A그룹이 통제군보다 더 크게 감소하였다. 이러한 결과는 복합운동을 할 때 유산소운동 형태보다는 저항운동의 비율을 높여주는 것이 신체조성과 대사관련 인자 개선에 효과적이라는 것을 확인시켜 주는 것이며 본 연구의 결과로 볼 때 복합운동의 강도는 WT의 비중을 높게 설정하는 것이 바람직할 것으로 생각된다.

• 한국재료학회지
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• 제14권6호
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• pp.375-378
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• 2004

The samples were prepared with hydroxyapatite(HAp) powder and eugenol (Eugenol/HAp = 15, 20, 25, 30wt%). The samples were dried at room temperature. The higher mechanical properties was observed in HAp sample with 25wt% Eugenol. The average compressive and bending strength in HAp with 25wt% Eugenol are 542 kgf/$\textrm{mm}^2$ and 366 kgf/$\textrm{mm}^2$ respectively. This strength is higher compare to that of the cortical bone.