• 대한치과교정학회지
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• 제24권2호
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• pp.295-301
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• 1994

The movement of teeth during orthodontic treatment requires bone remodeling process in periodontal tissue. To find out the changes occuring in the cell itself, mechanical force was applied to the cultured periodontal ligament cells. Following results were obtained from measuring the changes in cyclic AMP and $PGE_2$, $^3H$-thymidine incorporation amount in time lapse after application of mechanical force. 1. When mechanical force was applied to cultured PDL cells, the amount of cAMP in cells were increased significantly after 15 min. of force application, but were decreased gradually as time lapsed. 2. When mechanical force was applied to cultured PDL cells, the amount of PGE2 were increased at 20,40,60 min. and was significantly increased at 20 min. 3. When mechanical force was applied to cultured PDL cells, the amount of $^3H$-thymidine incorporation was some increased, but was not statistically significant.

• Restorative Dentistry and Endodontics
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• 제41권2호
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• pp.121-129
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• 2016

Objectives: The purpose of this study was to assess the effect of single and combined applications of fluoride on the amount of fluoride release, and the remineralization and physical properties of enamel. Materials and Methods: Each of four fluoride varnish and gel products (Fluor Protector, FP, Ivoclar Vivadent; Tooth Mousse Plus, TM, GC; 60 Second Gel, A, Germiphene; CavityShield, CS, 3M ESPE) and two fluoride solutions (2% sodium fluoride, N; 8% tin(ii) fluoride, S) were applied on bovine teeth using single and combined methods (10 per group), and then the amount of fluoride release was measured for 4 wk. The electron probe microanalysis and the Vickers microhardness measurements were conducted to assess the effect of fluoride application on the surface properties of bovine teeth. Results: The amount of fluoride release was higher in combined applications than in single application (p < 0.05). Microhardness values were higher after combined applications of N with FP, TM, and CS than single application of them, and these values were also higher after combined applications of S than single application of A (p < 0.05). Ca and P values were higher in combined applications of N with TM and CS than single application of them (p < 0.05). They were also increased after combined applications of the S with A than after single application (p < 0.05). Conclusions: Combined applications of fluoride could be used as a basis to design more effective methods of fluoride application to provide enhanced remineralization.

• 한국기후변화학회지
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• 제10권3호
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• pp.237-242
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• 2019

Ammonia is main precursor gas of secondary particulate matter and contributes almost 78% of total ammonia emission from the agricultural sector in Korea. The current method of estimating ammonia emission from fertilizer application, which contributes 7% of the total emission, has high uncertainty and needs to be improved to better predict PM2.5 concentration. In this study, we suggest an improvement method for ammonia emission quantification from fertilizer application. The first improvement was in the emission factor of NPK fertilizer by conducting a field study to verify the currently used factor. The improved NPK emission factor of 52.2 kg NH ton-1N was confirmed by comparing with the value from the EEA (European Environment Agency) and adjusting the value for the Korean climate and soil conditions. We also improved the amount of fertilizer usage by including the sales amount to the fertilizer supply amount of the Korean Farmers Association, increasing total fertilizer usage by 39.8%. As the statistical data on fertilizer supply and sales are compiled yearly, we estimated monthly emission of ammonia by considering cultivated areas and timing of fertilization for each crop. In summary, we suggest a novel and practical method to improve estimation methodology of ammonia emission from the field of fertilizer application: 1) emission factor of NPK fertilizer was reconfirmed; 2) total amount of fertilizer use was revised considering fertilizer sales; and 3) monthly emission of ammonia was realized by considering different crop practices. A bottom-up approach to compile activity data is needed to increase the estimation accuracy of monthly emission of ammonia, which is very helpful for predicting PM2.5 concentration.

• 한국토양비료학회지
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• 제33권3호
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• pp.167-174
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• 2000

본 연구는 2년간('97~'98) 벼 2모작 재배시 질소시용량별 보릿짚의 분해정도(分解程度)와 벼 생육(生育) 및 수량성(收量性) 변이(變異)를 조사하기 위하여 전북통(全北統)에서 시험한 결과는 다음과 같다. 보릿짚의 탄소잔존률(炭素殘存率)은 질소시 용량이 많을수록 적어졌으나 질소잔존률(窒素殘存率)은 증가하였고 C/N율(率)은 낮아졌다. 보릿짚시용시 토양미생물(土壤微生物)은 방사선(放線菌)>셀룰로오스분해균(分解菌)>세균(細菌)>사상균(絲狀菌) 순으로 많았다. 보릿짚시용에 의한 질소기아현상(窒素飢餓現象)은 분얼기(分蘖期)에 나타났으나 질소 $144kg\;ha^{-1}$시용구에서는 나타나지 않았다. 보릿짚시용으로 초장(草長), 간장(稈長), 수장(穗長)이 짧아졌으나 질소 $103kg\;ha^{-1}$ 시용구에서는 보릿짚무시용과 큰차이가 없었다. 보릿짚시용시 쌀수량(收量)은 질소 $108kg\;ha^{-1}$ 시용구에서 보릿짚무시용구와 같았으며 질소 90, $144kg\;ha^{-1}$ 시용구에서는 보릿짚무시용구(無施用區) 대비(對比) 감소폭(減少幅)이 컸다.

• 한국유기농업학회지
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• 제23권4호
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• pp.923-938
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• 2015

This study was conducted to serve as the basis for establishing a standard cultivation, which enhances the alternative utilization of pig manure, a major cause of environmental pollution, by finding a means for reducing greenhouse gas emissions for eco-friendly cultivation. In a laboratory, $CH_4$ and $CO_2$ emission patterns were investigated corresponding to incremental pig manure treatments in paddy soil. The emissions peaked 12 to 27 days after manure application in the 100~400% applications. It was found that increasing applications of pig manure resulted an increase in $CH_4$ and $CO_2$ emissions. Additionally, application of more than 150% emitted a larger amount of these gasses than applying chemical fertilizer. However, the test application of 100% pig manure emitted a smaller amount of $CH_4$ and hence Global Warming Potential (GWP) than those emitted by chemical fertilizer. If appropriate amount of fertilization is applied in compliance with the standard application rate, the pig manure may be effective in reducing greenhouse gas emissions and the soil environment made more favorable than with the use of chemical fertilizer.

• 농업과학연구
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• 제50권2호
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• pp.181-192
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• 2023

Appropriate fertilization methods are required according to species to supply necessary nutrients to plants and prevent soil environmental contamination in nurseries. In this study, the effects of nitrogen and phosphorus fertilization on the growth of Liriodendron tulipifera and soil characteristics were investigated. After 16 fertilization treatments (4 levels of nitrogen × 4 levels of phosphorus) were applied to one-year-old L. tulipifera seedlings at the Yongmun Nursery Station of the Korea Forest Service, height, root collar diameter (RCD), biomass, leaf nutrients, and soil characteristics were investigated. The height increased as the amount of nitrogen and phosphorus fertilization increased, and the RCD was the highest in the ×2 treatment. Biomass growth was on average 40.0% higher for the treatment with high nitrogen fertilization compared to the low nitrogen treatment. The seedling quality index was the highest with nitrogen and phosphorus ×2 treatment. Leaf phosphorus and magnesium concentrations decreased when nitrogen fertilization was applied, and leaf potassium concentrations decreased as nitrogen fertilization increased. Soil pH and exchangeable potassium decreased as the amount of phosphorus application increased, and exchangeable magnesium decreased as the amount of nitrogen application increased and increased as the amount of phosphorus application increased. Considering the growth of L. tulipifera seedlings and changes in the soil characteristics at the nursery stage, twice the standard fertilization amount is the appropriate fertilization amount for nursery of the Yongmun Nursery Station. It is expected that this study will contribute to improving nursery soil fertilization management technology for healthy seedling production.

• 한국환경농학회지
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• 제21권4호
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• pp.248-254
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• 2002

가축분뇨를 혐기성소화하여 메탄가스를 생산하고 난 다음 혐기성 소화액비를 비료자원으로 활용하기 위하여 농가포장에서 액비의 시용적량을 구명하였다. 벼 생육상황은 액비 100%+화학비료구가 전 시기를 통해 가장 양호하였으며, 그 다음으로 표준시비구가 분얼기에만 양호하였으나 그 이후에는 표준시비구 액비 100%구 및 액비 150%구 간에는 서로 차이가 없었다. 시기별 식물체중 전질소함량은 분얼기 및 출수기에는 추비의 영향으로 표준시비구가, 유수형성기에는 액비 100%+화학비료구가 높았다. 벼 수량은 액비 100% 및 150%구들이 표준시비구와 비슷하거나 약간 증수되었으며, 액비 100%+화학비료구는 고중의 증가 및 도복으로 인하여 표준시비구보다 수량이 오히려 약간 낮았다. 수확기 질소흡수량은 표준시비구가 가장 높았고, 시비질소 효율은 액비 100%구에서, 시비질소 이용율은 액비 100%+화학비료구에서 높았다. 시기별 토양중 $NH_4-N$ 및 $NO_3-N$함량 변화는 액비 100%+화학비료구가 타 처리구보다 높았다. 시기별 관개수 중 $NH_4-N$ 및 $NO_3-N$함량 변화는 분얼비의 영향으로 급격히 증가하였다가 급격히 감소하였는데, 증가한 시기에는 표준시비구 및 액비 100%+화학비료구가 가장 높았다. 시기별 침투수 중 $NH_4-N$함량 변화는 액비 150%구들에서 많이 용탈되었고, $NO_3-N$ 함량은 액비에 화학비료를 추비한 구들에서 많이 용탈되었다. 혐기성 소화액비는 액비 중의 질소성분을 분석하여서 표준시비량의 질소성분에 맞추어 시용하여야 한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.142-145
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• 2005

Since the successful launch of FORMOSAT -2 satellite by National Space Organization of Taiwan in May 2004, the Remote Sensing Instrument (RSI) on- board the FORMOSAT -2 has continuously acquired images at one panchromatic and four multi-spectral bands (http://www.nspo.org.tw). In general, the RSI performs well and receives high quality images which proved to be very useful for various applications. However, some RSI panchromatic products exhibit obvious trembling artifact that must be removed. Preliminary study reveals that the trembling artifact is caused by the instability of the spacecraft attitude. Though the magnitude of this artifact is actually less than half of a pixel, it affects the applicability of panchromatic products. A procedure removing this artifact is therefore needed for providing image products of consistent quality. Due to the nature of trembling artifact, it is impossible to describe the trembling amount by employing an analytic model. Relied only on image itself, an algorithm determining trembling amount and removing accordingly the trembling artifact is proposed. The algorithm consists of 3 stages. First, a cross-correlation based scheme is used to measure the relative shift between adjacent scan lines. Follows, the trembling amount is estimated from the measured value. For this purpose, the Fourier transform is utilized to characterize random shifts in frequency domain. An adaptive estimation method is then applied to deduce the approximate trembling amount. In the subsequent stage, image re-sampling operation is applied to restore the trembling-free product. Experimental results show that by applying the proposed algorithm, the unpleasant trembling artifact is no longer evident.

• 치위생과학회지
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• 제8권2호
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• pp.103-107
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• 2008

본 연구는 실제적으로 어린이를 대상으로 구강보건교육을 시행하고 있는 구강보건교육자인 치위생과 학생 80명을 대상으로 Pea-size로 짜는 방법과, 가로짜기로 짜는 방법으로 짠 세치제 양을 비교하였고, 5~7세 어린이 66명을 대상으로 평소 잇솔질 시 통상적으로 세치제를 짜는 방법과, Pea-size 및 가로짜기 방법으로 짠 양을 비교하여 평가하여 다음과 같은 결과를 얻었다. 1. 치위생과 학생들이 Pea-size 방법으로 짠 세치제의양은 0.40 g, 가로짜기 방법으로 짠 세치제의 양은 0.34 g으로 유의한 차이가 나타나 가로짜기로 짰을때 더 적은양의 세치제를 짜는 것으로 나타났다(p < 0.05). 2. 5~7세 어린에서는 평소 통상적으로 짜는 방법대로 짠 양이 0.40 g, Pea-size 방법으로 짠 세치제량은 0.43 g, 가로짜기 방법으로 짠 세치제량은 0.26 g으로, Pea-size 방법으로 짠 세치제량 가장 많았다. 따라서 현재 구강보건교육시 권고하는 Pea-size 방법을 고려해야 할 필요성이 있다고 생각되었다. 3. 어린이들이 세치제를 짜는 방법별로 사용된 세치제량을 비교해 본 결과, 가로짜기 방법으로 짠 세치제량을 Pea-size로 짠 세치제량과 비교했을 때 약65%,통상적인 방법으로 짠 세치제량과 비교했을 때 약 60% 감소를 보여주었다. 뿐만 아니라 어린이들에게서 가로짜기방법으로 짠 세치제량의 편차가 더 적은 것을 역시 확인할 수 있었다. 4. 가로짜기 방법은 부모나 어린이에게 구강보건교육 시 짜는 방법을 보여주며 교육할 수 있으므로 효과적일 뿐만 아니라, 불소세치제 사용량의 감소로 부주의한 불소 섭취를 최소화할 수 있어 어린이에게 추천할 수 있다.

• 대한소아치과학회지
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• 제24권1호
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• pp.148-172
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• 1997

Sixty human premolar teeth were used for this in vitro study. After each tooth was sectioned mesiodistally, one half was used for the experimental group and the other half for the control. Three groups were made for each fluoride applying method and twenthy teeth were assigned to each group. Ten teeth were used for evaluating total fluoride amount and the other ten were used for firmly-bound fluoride. Fluorshield was used for fluoride-releasing sealant and 1.23% APF, 0.05% NaF were used for topical application fluorides. Each tooth was cleaned with a tooth brush using nonfluoride containing pumice before the experiment. In the sealant group, fluoroshield was applied to the enamel surface without etching procedure and stored in $37^{\circ}C$ saline for 30 days. After 30 days, sealant was removed with explorer without scratching the enamel surface and washed with distilled water and dried. In the APF group, each tooth was immersed in 1.23% APF for 30 min then washed and dried in the same manner. In the NaF group, each tooth was immersed in 0.05% NaF for 24 hours then washed and dried as described above. After each fluoride regimen was applied, ten teeth were randomly selected from each group and immersed in 1M KOH solution for 24 hours to remove loosely-bound fluoride possibly deposited by the three different fluorides applied. In each group, total fluoride amount deposited and the amount of enamel removed by acid biopsy were calculated. After loosely-bound fluoride was removed, firmly-bound fluoride deposited and the amount of enamel removed by acid biopsy were also calculated. Total fluoride amount deposition was significantly increased in the APF and NaF groups, but not in the sealant group. Amount of enamel removed by acid-biopsy was also significantly diminished in the APF and NaF groups, but not in the sealant groups. After loosely-bound fluoride was removed from each groups, no statistical difference was found in the amount of firmly-bound fluoride in any groups. Also no effect of firmly-bound fluoride on enamel dissolution was shown in any groups after loosely-bound fluoride was removed from each group. In conclusion, topical application method of APF or NaF is more effective than fluoride-releasing sealant application to make $CaF_2$ coating on enamel surface and $CaF_2$ coating is the main source for anticariogenic effect of fluoride. However, longterm anticariogenic effect of fluoride-releasing sealant should be further evaluated.