• 소성∙가공
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• 제32권2호
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• pp.67-73
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• 2023

To overcome a climate change, manufacturing complex-shaped electric mobility parts becomes one of the important issues for enhancing a performance of motor with reducing their weight. Therefore, development of laser-based additive manufacturing shed on light due to their flexible manufacturing capacity that can be suitable to solve the poor formability of Fe-Si alloys for electric mobility parts. Although there are several studies existed to optimize the performance of additively manufactured Fe-Si alloys, the post-annealing effect was not well investigated yet though this is important to control the texture and mechanical properties of additively manufactured parts. In the present work, annealing effect on the mechanical property and microstructure of additively manufactured Fe-4.5Si alloy was investigated. Because of the ordered phase initiation after annealing, the hardness of additively manufactured Fe-4.5Si alloy increased up to 1173 K while a hardness drop occurs at the 1273 K condition due to the micro-crack initiation. The response surface methodology result represents the 1173 K-5 h sample is an optimal condition to maximize the mechanical property of additively manufactured alloy without micro-cracks.

• 핵의학기술
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• 제15권1호
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• pp.34-38
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• 2011

표준섭취계수(Standard Uptake Value, SUV)는 PET 검사에 있어서 매우 중요한 지표이다. 그러나 이는 장비에 따라서 다르게 나타난다. 그러므로 실제의 SUV와 장비에 따른 SUV의 차이를 알아보고자 한다. 실험을 위해 사용된 PET scanner는 본원과 보라매 병원에서 사용하고 있는 Biograph True Point True V 40 (Siemens, USA), Gemini Dual (Philips, USA), Gemini TF 64 (Philips, USA) 총 3대로 이루어져 있다. SUV를 평가하기 위한 phantom은 NEMA PET phantom (Data Spectrum co., USA)이고 내부에 3개의 hot insert를 포함하고 있으며 총 중량은 6.8kg으로 phantom과 물의 중량을 합친 무게이다. 방사성동위원소는 $^{18}F$-FDG 25.9 MBq (0.7 mCi)와 29.6 MBq (0.8 mCi)을 사용하였고 스캔은 두 번으로 나누어 이루어졌다. 25.9 MBq (0.7 mCi)은 background에 3.7 MBq (0.1 mCi), insert 1에 3.7 MBq (0.1 mCi), insert 2에 7.4 MBq (0.2 mCi), insert 3에 11.1 MBq (0.3 mCi)이 주입되었고 29.6 MBq (0.8 mCi)은 background에 1.85 MBq (0.05 mCi), insert 1에 7.4 MBq (0.2 mCi), insert 2에 9.25 MBq (0.25 mCi), insert 3에 11.1 MBq (0.3 mCi)이 주입되었다. Uptake time은 20분이고 2 bed scan을 하였으며 bed 당 3분의 영상획득이 이루어졌다. 두 번의 실험 모두 실제의 SUV와 유사하게 나타났다. 방사능량이 소량일 경우에는 그 차이가 미미했으나 방사능량이 증가할수록 그 차이는 점점 벌어졌다. 하지만 그 차이 또한 크지는 않았다. 장비 별 차이를 백분율로 환산하면 Biograph의 경우 87.2%, Gemini Dual은 91.2%, Gemini TF 64는 85.9%로 나타났으며 이는 실제의 값에 유의하다. 장비 별로 분류해보면 Biograph와 Gemini Dual은 비슷한 결과를 보여주었고 다만 Gemini TF 64에서만 두 장비보다 낮게 나타났다. 실험 결과 장비 별로 SUV의 차이는 있으나 그 차이가 실제의 값에 유의하였다. SUV가 차이가 나는 이유는 장비 별 재원의 차이와 재구성 방법, 제조사 별 SUV 함수식에서 기원이 되는 것으로 파악되며 소량의 방사능량에서는 차이가 없으나 방사능량이 증가할수록 차이가 커지는 것으로 보아 이 점에서의 추후 고찰은 필요할 것으로 사료된다.

• 한국균학회지
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• 제3권1호
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• pp.1-19
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• 1975

Since the importance of casing in fruit body formation of Agaricus bisporus has been emphasized, physico-chemical characteristics of casing materials were discussed by many workers and a mixture of peat and mineral soil as proper casing material has been adopted in many of mushroom growing countries. Because of limited resources of peat in Korea, it is necessary to find practical performance and substitutional materials for casing. The effect of casing on mycelial growth and mushroom yield of A. bisporus varied with materials, its combination and practices etc. The experiments to be discussed in this paper are concerned with pH and Ca of casing material which influence A bisporus, and changes of physico-chemical characteristics with mixing ratio of casing materials and its effect on A. bisporus. The optimum range of moisture content of each material, management of watering and application of physico-chemical characteristics casing materials was also investigated and re-use of weathered spent compost for casing material was described. 1. The effect of calcium on mycelial growth of A. bisporus at various pH in Halbschalentest showed different results with calcium sources. Best results were obtained around neutrality and fresh weight of fruit bodies grown in the range of pH 7 to 8 was highest among the tested levels. 2. Available moisture, pore space, organic matter, cation exchangeable capacity and exchangeable cation was increased by an increase of mixing ratio of peat in casing materials, while an adverse effect was obtained by addition of sand. 3. Mycelial growth on clay loam was more rapid at a lower bulk density of 0.75g/cc and at 20% moisture content on a dry weight basis at the same bulk density. 4. Mixing ratio of casing materials, 60 to 80 per cent by volume of peat mixed with 20 to 40 per cent of clay loam produced the highest yield of fresh fruit bodies and sand the lowest. However, per cent of open cap was highest in peat and lowest in sand. 5. Days required for fruit body initiation was shortened in mixtures of peat and clay loam by one to three days compared with other materials and the formation of flushes was clear. 6. The effect of some physico-chemical characteristics of casing materials on the fresh weight of fruit bodies were estimated by a multiple regression equation; Y=-923.86+$8.18X_1+8.04X_2+7.90X_3+0.12X_4+2.03X_5-0.82X_6-0.54X_7$ where $X_1,X_2,X_3,X_4,X_5,X_6,X_7$ are sand, silt, clay, available moistuer, porosity, organic matter and exchangeable cation respectively. The productivity of certain casing material could be predicted from this equation. 7. Fresh weight of fruit bodies was positively correlated with porosity exchangeable cation, organic matter, available moisture, silt and clay of materials; while sand was negatively correlated. On the contrary, sand was the unique factor reducing per cent of open cap. 8. Distribution of three phases of high productive casing material was concentrated in the range of 10 to 30 per cent solids, 15 to 30 per cent liquids, and 50 to 60 per cent in air volume. 9. Fresh weight of fruit bodies from peat was not affected with heavy watering but in clay loam and sandy loam severe crop losses occurred. Fresh weight of individual fruit was increased and open caps were decreased with heavy watering but light watering resulted in adverse effects: its effect was especially great in peat. 10. Optimum range of moisture content by weight on a dry basis was different with each casing material. To maintain optimum moisture content concerned with yield of fruit bodies and open cap, sandy loam and peat mixtures required daily watering of 0.6, 0.6 to 1. 2 and 1.2 to 2.4 liters per $3.3m^2$ of bed area, respectively. 11. Maximum yield of fruit body was recorded in the range of pF 2. 0 to 2. 5 of casing materials if organic matter content was below 4.2 per cent and in pF 1. 3 to 1.8 if above 7.1%. 12. pF curve of a certain casing material could be draws from moisture content at various pF values by multiple regression equations provided texture, organic matter and calcium of the casing material are given. Optimum moisture range of the casing materials also could be estimated by the equation. 13. It was possible to improve the phyico-chemical characteristics of clay loam and sandy loam by addition of weathered spent compost although the effect was less than in the case of peat. Fresh weight of fruit bodies wsa increased by addition of weathered spent compost but its effect was not as remarkable as peat. Accordingly, further studies will be required.

• 한국간호교육학회지
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• 제5권2호
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• pp.359-375
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• 1999

This is a survey in order to provide basic information about menstrual pain management and dysmenorrhea management. Menstrual pain means low abdominal cramps during menstruation and dysmenorrhea means low abdominal pains, and other symtoms as lumbago, fatigue, G-I symptoms, etc. The purposes of this study were (1) to measure the menstrual pain and dysmenorrhea, (2) to determine factors influenced to them, and (3) to know self-management method for them of college students. The subject of this study consisted of 312 college students Data were collected by questionnaire which was to measure the menstrual pain(Visual Analogue Scale(VAS), dysmenorrhea (dysmenorrhea scale) and general informations from May to June, 1999. The results of this study were as follows ; (1) Mean age for subjects was 19.4 yrs, their height was 161.4Cm, weight, 50.9Kg, menarcheal age, 13.5yrs, menstural period, 30.1 days, and menstrual duration was 5.6 days. Most respondents replied that their menstrual bleeding was moderate (72.1%) and occured regularly(55.4%). (2) Mean menstrual pain was 5.20. Menstrual pain didn't be occured 17.4 % of respondents, periodically 46.0%, and intermittently 36.6%, most commonly beginning the first day of menstruation (3) Chief management method was endurance (40.4%), use of analgesics (29.5%) and bed rest(16.5%). (4) Factors influenced to menstrual pain were analgesics use, heavy bleeding, time of menstrual pain, life change during menstruation. (5) Most symptoms of dysmenorrhea were low abdominal pain(22.2%), lumbago (15.9%), fatigue(9.0%). (6) Factors influenced to dysmenorrhea were anlgesics use and menstrual pain. (7) By Pearson's correlation analysis, there was a significant correlation between menstrual pain and menarcheal age, menstrual period. menstrual duration. But there was no correlation between menstrual pain and height, weight (8) By Pearson's correlation analysis, there was a significant correlation between dysmenorrhea and menstrual period But there was no correlation between menstrual pain and menarcheal age, menstrual duration, height, weight The results demonstrate the importance of development and clinical trial of nursing intervention on menstrual pain and dysmenorrhea.

• 생물환경조절학회지
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• 제13권1호
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• pp.21-25
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• 2004

브로콜리의 측지재배에 있어서, 엽령이 다른 시기의 생장점 제거가가 브로콜리의 생육 및 수량에 미치는 영향을 검토하였다. 적심은 육모기중 본엽 2매, 3매, 4매시에 실시하였으며, 무적심을 관행재배로 하였다. 초장은 처리간 생육차이를 보이지 않았으나 생체중은 적심시기가 늦어짐에 따라 감소되는 경향을 보였다. 적심처리의 경우 무적심에 비하여 엽수 및 측지수가 증가하였다. 정화리 형성일은 2매 적심처리에서 무적심에 비하여 3일 정도 빠라졌다. 정화뢰(첫번째 화뢰) 무게는 무적심에서 244g으로 가장 무거우T으며, 적심처리의 경우 무적심에 비하여 엽수 및 측지수가 증가하였다. 정화뢰 형성일은 2매 적심처리에서 무적심에 비하여 3일 정도 빠랄졌다. 정화뢰(첫번째 화뢰) 무게는 무적심에서 244g으로 가장 무거웠으며, 적심처리의 경우 적심시기가 늦어짐에 따라 감소되었다. 2번째 화뢰중은 본엽 2매 적심처리에서 157g으로 가장 무거웠다. 총 화뢰중은 본엽 2매시 적심처리에서 378g으로 가장 무거웠으며, 4매 적심시 196g으로 가장 가벼웠다. 상품수량은 무적심 1,184kg에 비하여 본엽 2매 적심시 1,754kg으로 48%의 증수효과를 보였으며, 본엽 4매 적심시 820kg으로 가장 적었다. 첫 수확일은 본엽 2매 적심처리에서 무적심에 비하여 6일 정도 조기수확이 가능하였다.

• 한국토양비료학회지
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• 제45권6호
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• pp.1037-1042
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• 2012

충남 부여군 석성면 양송이 재배 농가에서 채취한 양송이 수확 후 배지로부터 auxin생성능이 뛰어난 세균 2SJ8-02 균주를 분리하여 TLC 및 HPLC 분석을 통해 확인한 결과, IAA 생산농도는 $122mg\;L^{-1}$이었으며 LC-Mass분석에 의하여 생성된 물질은 분자량이 175인 IAA로 확인되었다. 분리균에 의한 IAA 생산을 위한 최적조건을 실험한 결과, 0.1% L-tryptophan를 함유한 pH 7.0의 R2A broth배지에 $35^{\circ}C$, 24시간 배양 시 최대 이었다. 녹두발근 생검법과 pot 재배를 통한 식물생육효과 실험에서 분리균 배양액의 첨가는 대조구에 비해 발근수와 뿌리길이에서 약 2배의 뿌리신장효과를 보였다. 생리적 특성 및 계통학적 특성분석을 통해 분리균은 Gram 음성 간균인 Pantoea rwandensis 2SJ8-02로 동정되었다.

• 한국조경학회지
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• 제18권4호
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• pp.73-85
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• 1991

Rhododendron mucronulatum for. albiflorum, native species is a shrub that has white flowers on May to June, and rare species endangered by people's rash digging or cutting. But its physiological ecological characteristics and propagation method are not being known at all. Therefore, this study was executed to utilize this species as the planting material for landscaping by analysing its habitat environment and growth form, and also experimenting its seed and vegetative propagation, and it field culture and utilization. The results are as follows; 1. The elevation, gradient and direction of this species were 295-1,350m, 10-36$^{\circ}$, northwest respectively. It was found that the species is shade-liking plant that grows under forest cover of average 51.33%. 2. The soil pH and water content of its habitat were 5.4, 25.41% respectively. The organic matter content was 6.29% that was higher than 3.2%, the average organic matter content of forest soil in Korea. 3. Representative plant community within which this species was living was Quercus mongolica community, and its main neighboring species were Lindea obtusiloba, Fraxinus sieboldiana, Rhus trichocarpa, Rhododendron Schlippenbachii, Rododendron mucronulatum. 4. The leaf length and width of this species were 39.18mm, 12.60mm respectively. This result showed that generally its leaf size was larger than that of R. micranthum, R. yedoense var. poukhanense and R. mucronulatum var. ciliatum and smaller than that of R. mucronulatum and R. schlippenbachii. 5. The whole size of its pollen was, as 59${\times}$61$\mu\textrm{m}$, the largest of plants of Rhododendron family including R. mucronulatum and R. mucronulatum var. ciliatum. 6. The result of seed germination experiment at intervals of 5$^{\circ}C$ from 15$^{\circ}C$ to 30$^{\circ}C$ presented the highest germination rate of 94.7% at 20$^{\circ}C$ numerically, but high percent germination at all temperature levels without significant difference. And the seed of this plant proved to be sun-liking seed at requiring dormancy in germination. 7. Through seed germination experiment by treatment of growth regulators such as GA. Thiourea and Kinetin under dark condition, it was found that the effect of GA treatment on germination increase and acceleration was the highest. 8. In greenwood cutting, rooted rate by treatment of various concentration of IBA and NAA on clay and vermiculite bed was not wholly high, but 100ppm plots of both IBA and NAA of clay bed showed relatively good rooted rate. 9. As result of field culture experiment for finding out optimum growth temperature and light intensity, growth conditions such as height, number of leaves, fresh weight and chlorophyll contents were the best at night/day temperature of 20/25$^{\circ}C$ and under 1/2sun. Also, the photosynthetic rate was the highest at 25$^{\circ}C$. Accordingly, it was found that optimum temperature and light intensity for growth of this plant are 25$^{\circ}C$ (day temperature), 50% of natural light respectively.

• 한국산림과학회지
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• 제70권1호
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• pp.72-76
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• 1985

외생균근(外生菌根)을 형성(形成)하는 모래밭 버섯균(菌)(Pisolithus tinctorius) (Pt)을 포플러에 인공접종(人工接種)하여 기주(寄主)의 생장촉진(生長促進)과 활착률(活着率) 증진효과(增進效果)를 조사(調査)하였다. 질석(蛭石), 니탄(泥炭)이끼, MMN배지(培地)(Modified Melin-Norkrans)를 첨가(添加)한 $1{\ell}$ 유리 용기(容器)에 Pt 균(菌)을 대량(大量)으로 배양(培養)하여 Methyl bromide($50g/m^2$)로, 훈증(熏蒸)한 묘포토양(苗圃土壤)에 혼합(混合)하고, 은수원사시 (Populus alba${\times}$P. glandulosa)를 삽목(揷木)하였다. $1{\times}2m$ 크기의 삽목상(揷木床)에 50개(個)의 삽수(揷穗)를 사용(使用)했으며, 삽목당년(揷木當年) 가을에 수고(樹高), 건중량(乾重量)(지상부(地上部)), 활착률(活着率)을 조사(調査)하였다. Pt로 접종(接種)된 묘목(苗木)은 접종(接種)안된 묘목(苗木)보다 수고생장(樹高生長)에서 19% 더 빨리 자랐으며, 지상부(地上部)의 건중량(乾重量)에서 49% 더 많았다. 삽목(揷木) 활착률(活着率)도 접종(接種)된 묘목(苗木)이 접종(接種)안된 묘목(苗木)보다 20% 증가(增加)하였다. 접종(接種)된 묘목(苗木)에는 Pt 균(菌)의 전형적(典型的)인 황갈색(黃擖色)을 띤 세근(細根)이 많이 발달(發達)했으며, 꼬불꼬불한 root tip 형태(形態)를 보였다. 접종(接種)된 삽목상(揷木床)에서 9월(月) 중순(中旬)에 Pt균(菌)의 자실체(子實體)가 생산(生産)되어서, 접종(接種)과 균근형성(菌根形成)이 성공적(成功的)이었음을 입증(立證)해 주었다.

• 대한토목학회논문집
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• 제31권3B호
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• pp.205-209
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• 2011

배수관로 내의 토사퇴적으로 인한 통수능 저하는 도시홍수의 주요 발생 원인으로 배수관로의 효율적 유지관리는 도시홍수 예방에 대단히 중요하다. 따라서 본 연구에서는 만관 원형관로에서의 토사이송 실험을 실시하고 배수관로 내에서 일어나는 유사이송 형태, 흐름의 저항 및 유사량 등 수리학적 특성을 분석함으로써 관로의 효율적 유지관리를 위한 기초 자료를 제시 하였다. 본 실험은 길이 8 m, 관경 60 mm의 수평 관로와 유사 공급장치로 구성된 모형장치을 통하여 실내실험을 수행하였다. 실험장치는 최대 $30m^3/hr$ 규모의 유량 순환시스템을 갖추고 있으며 관로 상류부에 5 g/s~19 g/s 규모의 유사 공급 장치와 함께 관로 끝부분에 유사 회수시스템을 갖추고 있다. 본 연구 수행 결과 통수단면의 평균유속(U), 점성계수(${\mu}$), 단위 폭당 소류사량($q_b$), 평균입경($d_{50}$), 수중유사단위중량(${\gamma}^{\prime}_s$)를 주요 인자로 하는 두 개의 무차원 변수를 이용하여 압력 원형관로 내 토사이송을 예측하는 공식을 제안하였으며 이들 무차원 변수 간에는 선형 상관관계가 있음을 확인하였다.

• 한국산학기술학회논문지
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• 제16권8호
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• pp.5534-5540
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• 2015

철도 신호제어시스템에서 열차의 위치 및 점유 유무를 검지하기 위하여 궤도회로 이외에 axle counter적용 사례가 증가하고 있는 추세이다. 이에 본 연구에서는 열차검지 및 차축계수의 신뢰성을 높이기 위해 axle counter의 센서 방식을 지자기 센서 방식과 근접센서 방식을 비교하였으며, 그에 따른 차이점과 결과를 제시하였다. 또한, 정확한 차축검지를 위한 센서부의 취부조건 등을 고려한 설치에 대해 현장 경험을 기반으로 적용된 결과를 제시한다. 본 연구에서는 차축검지의 신뢰성 향상을 위해 센서의 위상차를 판단할 수 있도록 설계 변경한 결과 차축검지 기능뿐만 아니라 다양한 기능까지(열차의 방향검지, 열차속도검지 등) 수행할 수 있는 확장성을 확보하였다. 또한 열차의 종별, 무게 등의 특성에 종속되지 않았으며, 자체적으로 제작한 차축검지를 위한 모의차축 이송장치와 Test Bed를 구축하여 Lab. 테스트를 수행한 결과 350km/h의 속도에서도 차축 검지의 누락이 발생하지 않았음을 확인하였다. 이를 통해 열차의 검지뿐만 아니라 통과하는 열차의 속도와 편성 수, 선로전환기 통과 시 철사쇄정 조건 그리고 건널목 장치에도 적용할 수 있는 기반을 마련하였으며, 향후 철도 신호제어 시스템 전반에 확대 적용하게 되면 열차안전운행에 많은 기여를 할 것으로 판단된다.