• Journal of agriculture & life science
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• v.45 no.3
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• pp.89-96
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• 2011

The objective of this study is to evaluate reduction efficiency of various air purifiers on airborne microorganism causing air infected animal disease according to sample collection method. Collection efficiencies of MS2 virus and Pseudomonas fluorescens by biosampler was significantly higher than those by button sampler (p<0.05). Regardless of types of air purifier and sample collection method, temporal reduction efficiencies of MS2 virus and P. fluorescens compared to initial background concentration were >50% and >45% on 5 minutes, >70% and >50% on 15 minutes, >80% and >70% on 30 minutes and >90% and >75% on 60 minutes after operating air purifier, respectively. The air purifier of ionizer type showed the highest reduction efficiency on MS2 virus followed by air purifier of electronic precipitation, water filter and dry filter while the reduction efficiency of air purifier on P. fluorescens was highest in the electronic precipitation type followed by ionizer type, dry filter type and water filter type (p<0.05). Based on the results obtained from this study, temporal reduction efficiency of air purifier on MS2 virus was relatively higher than P. fluorescens.

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.4
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• pp.319-326
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• 2013

In the present study, we investigated the effects of high forage diets on the volume of udder, hormone level in blood, and lactation characteristics in the Holstein dairy cow. We divided into two groups; high forage diet [HF, concentrate: forage=4:6 n=41] and low forage diet [LF, 6:4 n=21]. Five cows were selected from each group based on their age for measuring the udder volume and the serum levels of estradiol and progesterone. Lactation characteristics were compared between HF and LF. The udder volume was 2.5 fold larger in HF at early gestation (p<0.01), but no difference was noted afterward. For the hormone levels, no significant difference was found between the groups. In HF, milk yield was significantly increased and maintained high longer, while somatic cell count was approximately 50% lower. Meanwhile, the milk fat content was significantly lower in HF during early lactating phase (p<0.001), but there was no difference thereafter. For milk protein and solid content, and MUN, no differences were found between the groups during lactation. Our results indicated that feeding high forage diets to dairy cows can increase milk yield and quality without notable changes in the udder volume and hormone level.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.259-260
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• 2012

산업화가 발달됨에 따라 대기 오염 물질은 점차 증가하고 있는 추세에 있고 특히 기름 및 석탄 연소 보일러, 자동차, 제철, 시멘트 플렌트, 소각로 등은 미세 분진을 발생시키는 주원인이 되어 왔다. 최근 대기환경법은 오염 분진의 중량 규제로부터 $10{\mu}m$ 미만의 PM10에서 $2.5{\mu}m$ 미만의 PM2.5의 미세 분진에 대한 규제로 점차 심화되고 있으나, 이러한 미세분진은 고전적인 제거 방법으로는 매우 어려우며 고가의 HEPA 필터를 사용하여야 한다. 한편 코로나 방전을 이용하는 전기 집진은 미세 먼지 제거에 매우 효율적이어서 $1{\mu}m$ 미만의 미세 분지도 99%까지 제거가 가능하다는 장점이 있지만 입자크기가 클 경우에는 효율이 떨어지는 단점이 있다. 한편 사이클론 집진기는 매우 오래전부터 개발되어 사용되어 왔는데 가격이 저렴하고 운영비가 적게 들며 $10{\mu}m$ 이상의 먼지는 99% 이상 제거가 가능하여 산업현장에서 오랜 기간 사용되어 왔지만 입자크기가 $10{\mu}m$ 미만으로 가면 집진율이 급격히 떨어지는 단점을 가지고 있다. 본 연구에서는 기존의 사이클론 집진기의 구조를 기본으로하여 사이클론 집진기 내부에 플라즈마 방전을 설치하여 원심력에 의한 집진과 코로나 방전에 의한 전기 집진을 동시에 수행할 수 있도록 하이브리드 사이클론 집진기를 제작하였다. 제작된 사이클론 집진기는 직경 30 cm 높이 120 cm의 사이클론 구조를 가지고 있으며 1 hp의 터보송풍기를 장착하여 $20m^3$/min 이상의 유량을 처리할 수 있도록 설계 제작되었다. 제작된 하이브리드 사이클론 집진기의 성능을 평가하기 위하여 $10m^3$의 체적을 가지는 테스트 챔버 내부에 사이클론 집진기를 설치하고 향을 태워 미세 먼지를 발생시킨 후 다양한 조건에서 집진 성능을 측정하여 보았다. 미세 먼지의 경우 사이클론을 작동시키지 않아도 테스트 챔버 벽면에 흡착되어 초기에는 급격히 감소하는 경향을 보여주나 일정 시간이 경과한 후에는 매우 느리게 감소하는 현상이 관찰 되었다. 코로나 방전을 하지 않고 오존 파괴기에 활성탄만 충진한 상태에서 사이크론을 작동시킬 경우 지속적으로 천천히 감소하는 경향을 보여주었으며, 코로나 플라즈마를 방전시킨 경우 미세 먼지는 HEPA filter를 장착한 것보다도 조금 빠르게 미세먼지를 제거하였다. 챔버 내부의 미세먼지가 초기 값의 1/10에 도달하는 시간은 코로나 방전 전류가 증가할수록 짧아지는 경향을 보여주었으며 최적 조건에서 100초 이내에 90% 이상 제거가 가능하였다. 하이브리드 사이클론 집진기는 집진 뿐 만 아리라 VOC 성분도 분해가 가능하여 유해물질을 제거하는 능력이 있다. 유해 가스 제거 능력을 실험하기 위하여 분진제거 실험에 사용된 챔버 안에 아세톤을 증발시켜 50 ppm이 되도록 한 후 다양한 조건에서 유해물질 제거 실험을 수행하였다. 미세먼지와는 달리 장비를 작동하지 않을 경우 매우 느리게 아세톤 농도가 감소하였다. 이는 미세 먼지와는 달리 흡착이 발생하지 않고, 측정 챔버 자체가 완전한 밀폐가 이루어지지 않아 자연적으로 조금씩 외부로 누출되기 때문으로 판단된다. 코로나 플라즈마만 방전시켰을 경우 초기 농도의 80%가 제거되는데 걸리는 시간은 약 28분 정도로 코로나 플라즈마가 VOC 제거에 효과가 있음은 확인하였으나 제거율이 그리 높지 않음을 알 수 있었다. 한편 오존 파괴를 위해 활성탄으로 충진 된 오존파괴기를 통과시킨 경우는 약 12분 경과 후 80%가 제거됨을 확인할 수 있었으나 그 이후에는 VOC의 감소가 매우 느리게 진행됨을 알 수 있었다. 한편 활성탄 대신 $MnO_2$ 복합촉매로 충진 된 오존파괴기를 통과한 경우 약 3분 정도 경과 후 80%의 아세톤이 제거됨을 관찰할 수 있었으며 코로나 플라즈마를 작동시키면서 $MnO_2$ 복합촉매로 충진 된 오존파괴기를 통과시킨 경우 약 2분 정도 경과 80% 이상의 아세톤이 제거되어 코로나 플라즈마와 복합촉매를 사용할 경우 VOC 성분이 효과적으로 제거됨을 알 수 있었다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.2
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• pp.50-56
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• 1964

1. Five varieties of kenaf, Hibiscus cannabinus L., were used for study the influence of various patterns on flowering and fertilization. e statistical analysis on the percentage of flowering in given time gave highly significant different patterns among five varieties examined. Korean local kenaf was flowered very early, whereas Everglades 71 flowered very late. Both Guatemala 38F and Guatemala 2A introducedf rom Guatemala were flowered intermediately to compare with Korean local and American varieties. 3. The data indicate that low temperature was given delayed flowering time which means the flowering time was closely related with temperature having the flowering time was accelerated more or less early by high temperature. 4. It was shown that the fertilization after pollination was needed for five to six hours. 6. It was examined that the adequate crossing time between different varieties on the kenaf was the time of heavy flowering.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.79-89
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• 2003

The purpose of this study is to investigate appropriate environmental factors when domestic waste is decomposed as aerobic digestion. So stabilization degree was measured after the waste is mixed as certain rates and water content was controlled by 55% and 60%. Variation of VS showed food waste in reactors of number 1, 2, 3, 4 and 5 was decomposed fully except reactor of number 6. Decomposition degree of VS in reactors of number 1, 2, 3 and 4 was not different high because Vinyl and plastic inserted played role bulking agent in reactor number 1, 2, 3 and 4. In reactors, maximum temperature indicated $57{\sim}59^{\circ}C$ and temperatures in reactors 1, 2, 3 and 4 were higher and remained longer than in reactor 5 and 6 for 2~4 days. Variation of $CO_2$ was similar to that of VS. The reduction rate of water content was low because moisture generated by oxidation fever of microorganism did not evaporated well. pH was low in the beginning of the reaction however, as time passed, it increased slightly and remained regular pattern. EC and C/N showed the same pattern as pH. Settlement and weight reduction rates were similar to the factors above. Reactor 1, 2, 3, and 4 showed higher settlement and weight reduction rate than reactor 5 and 6.

• Korean Journal of Organic Agriculture
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• v.27 no.3
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• pp.365-380
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• 2019

Total of 20 Holstein calves of 10 calves (3.90±0.26 month of age) born in spring (S) and 10 calves (4.10±0.30 month of age) born in fall (F) were reared in this study for 24 months and diets were divided into separate feeding of forage and concentrates (C) and TMR (T). Therefore, 4 treatments in this study were composed of CS, CF, TS and TF with the factors of diets and calving season. After parturition of heifers, all animals were fed the same diet and milk production was recorded monthly. DM intakes in growing period were influenced by calving season, and those of the animals calved in fall were higher than in those calved in spring (P<0.01), but there were no significant differences by feeding method. CP intakes and TDN intakes were significantly influenced by calving season (P<0.05) and feeding method (P<0.001), and the animals calved in fall were about 1.2% higher than those calved in spring, and the animals fed TMR were about 4.7% higher than those fed concentrates and forage separately. Average, 9th and 10th months' milk yields were significantly influenced by feeding method in which those in the treatments fed TMR (TS, TF) were higher than in separate feeding of concentrates and forage (CS, CF; average P<0.05; 9th and 10th months P<0.01). Average milk persistency was also significantly influenced by calving season (P<0.05) and feeding method (P<0.01) and those in the animals calved in fall were higher than in spring and those of the TMR fed animals were also higher than in separate feeding of concentrates and forage. Milk persistency was similar to the results of milk yield, showing statistically significant differences affected by the feeding method at 9th and 10th months of late lactation (P<0.01), and it was about 8% higher in the animals fed TMR, showing higher tendency at 7th (P=0.12) and 8th months of late lactation (P=0.09). Therefore, it is expected that postpartum milk yield and milk persistency would be higher when the hiefers are fed TMR in growing period and calved in fall. Average milk fat content was influenced by feeding method. Milk fat content of the animals fed TMR during growing period were 7.8% higher than those fed concentrates and forage separately (P<0.01). This suggests that feeding TMR during growing period influenced first postpartum eating behavior, which stabilized the rumen and resulted in the increased milk fat. At 3rd month after calving, milk fat content was lower in the animals calved in spring than in those calved in fall, suggesting that it might have been influenced by the seasonal differences. MUN showed significant differences by feeding method in which those in separate feeding of concentrates and forages were higher especially in average, 4th, 5th and 6th months (average and 4th P<0.01; 5th and 6th months P<0.05). SCC was higher in the animals fed TMR than in those fed concentrates and forage separately especially in average, 3rd and 4th months after calving (P<0.01). In conclusion, when feeding TMR during growing period and calving in fall, it was not influenced by the high temperature in summer, and it resulted in the improved milk yield, milk persistency and milk fat content.

• 대한생식의학회:학술대회논문집
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• 2001.06a
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• pp.68.2-69
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• 2001

• Journal of Biomedical Engineering Research
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• v.21 no.2
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• pp.119-127
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• 2000

금속판/형과스크린 계측기와 CCD 카메라를 이용한 방사선영상장치가 현재 전자포탈영상에 널리 쓰이고 있다. 이 장치의 효율적인 영상획득을 위해 계측효율이 좋고, 공간분해능력이 뛰어난 금속판/ 형과스크린 계측기의 두께를 최적화할 필요가 있었다. 이 논문에서는 금속판과 형광스크린의 두께가 계측효율과 공간분해능에 미치는 영향이 연구되었다. 이 결과는 치료 엑스선 영상장치에 쓰일 수 있는 금속판/형과스크린 계측기의 최적화된 두께를 결정하는데 쓰일 수 있다. 몬테칼로 방법을 이용하여 계산한6 MV 선형가속기에서 발생되는 엑시선의 에너지 스펙트럼을 바탕으로, 여러 가지 두께의 금속판/형광스크린에 대하여 계측효율과 공간분해능을 계산하였고, 이를 실험을 통해 검증하였다. 계측효율은 입사된 엑스선의 에너지가 형광스크린에 흡수된 비율로 계산되며, 공간분해능은 흡수된 에너지의 공간 분포를 통해 계산되었다. 계측효율은 금속판의 두께에 의해, 공간분해능은 형광스크린의 두께에 의해 결정될 수 있음을 본 연구를 통해 확인할 수 있었고, 이로써 특정이용에 관련된 금속판/형광스크린의 두께에 대한 서로 보상 (trade-off) 관계에 있음을 계산과 측정결과를 통해 확인할 수 있었고, 이로써 특정이용에 관련된 금속판/형광스크린 계측기의 최적화된 두께를 산출할 수 있게 되었다. 계산을 바탕으로 CCD를 이용한 전자포탈영상장치의 시작품을 설계 및 제작하였고 팬텀을 이용하여 영상을 얻었다. 단일 프레임 영상은 노이즈가 많으나, 프레임 평균 방법을 이용하여 영상의 질을 향상시킬 수 있었다.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.227-238
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• 2009

The egg development and morphological changes of larvae, juveniles and adults of Oryzias dancena were observed. Fertilized eggs were incubated at $25{\pm}1^{\circ}C$; the process of embryonic development was observed by light microscopy and based on diagnostic features of the developing embryos. The average time to hatch was 11 days after fertilization. The hatched larvae averaged $4.40{\pm}0.24mm$ in total length (TL). The yolk sacs of the larvae were almost absorbed at 3 days after hatching and $4.55{\pm}0.23mm$ TL. At 21 days after hatching, the larvae were $7.23{\pm}0.73mm$ TL and had reached the juvenile stage. First ovulation was about 9 weeks after hatching and at $22.58{\pm}2.73mm$ TL.

• Journal of Korean Physical Therapy Science
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• v.3 no.3
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• pp.35-49
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• 1996

This study was conducted to see variation of vital sign of hot and cool bath according to time, a questionnair survey and measurement was carried out for 32 students(sophomore) of department of physical therapy Andong Junior College on the 27th of June, 1995. The result were as follows: The average systolic blood pressure(SBP) of stability for 32 college students who were measured was 105.3mmHg, the average diastolic blood pressure(DBP) was 67.3mmHg, the average pulse frequency(PF) was 70.7(frequency/min), the average respiratory frequency (RF) was 15.6 (frequency/min), and the body temperature(BT) was $36.6^{\circ}C$. As time went on, SBP for 32 students who were measured in hot bath according to stability, 3 min, 6 min, 9 min, and 12 min was decreased(105.15 mmHg, 104.69mmHg, 104.24 mmHg, 103.03 mmHg, and 96.69 mmHg)(P=0.3006). SBP was decreased in cool bath, too(105.15 mmHg, 103.33 mmHg, 103.33 mmHg, and 100.91 mmHg), but it at 12 min was a little higher(l03.09 mmHg)(P=0.7566). As time went on, DBP according to stability, 3 min, 6 min, 9 min, and 12 minutes was decreased in hot bath(66.82 mmHg, 65.45 mmHg, 64.54 mmHg, 63.03 mmHg, and 59.39 mmHg)(P=0.0906). It was similar in cool bath(66.82 mmHg, 67.87 mmHg, 68.48 mmHg, 67.87 mmHg, and 68.78)(P=0.9654). As time went on, PF was significantly increased in hot bath(70.42 times, 86.96 times, 93.57 times, 99.30 times, and 101.78 times)(P=0.0001). It was a little increased in cool bath, too (70.42 times, 70.85 times, 71.63 times, 71.06 times, and 71.45 times)(P=0.9803). As time went on, RF was significantly increased in hot bath(15.75 times, 19.09 times, 22.09 times, 24.94 times, and 26.48 times)(P=0.0001). I t in cool bath of stability, 3 min, and 6 min was a little increased(15.75 times, 19.30 times, 19.39 times), but it in 9 min(18.67 times), and 12 min(18.09 times) was a little decreased(P=0.0176). As time went on, BT was significantly increased in hot bath($36.63^{\circ}C,\;37.45^{\circ}C,\;37.81^{\circ}C,\;38.12^{\circ}C,\;38.33^{\circ}C$)(P=0.0001). It was a little increased in cool bath of stability and 3 min($36.63^{\circ}C,\;37.40^{\circ}C$), but others are similar($37.33^{\circ}C,\;37.37^{\circ}C$, and $37.36^{\circ}C$)(P=0.0001). It was revealed by this study, SBP and DBP according to time in hot and cool bath were decreased. PF, RF, and BT in hot bath were higher, RF and BT in cool bath were higher too. but PF was similar.