• 한국환경농학회지
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• 제24권1호
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• pp.66-70
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• 2005

The experiment was carried out to investigate the effects of gamma radiation on the early growth performance and physiological traits of BT2 clone tea, the most promising cultivar released by Bangladesh Tea Research Institute. The fresh shoot cuttings were irradiated with seven different levels of gamma radiation such as 0, 10, 20, 30, 40, 50 and 60 Gy from Cobalt 60Co source (Dept. of PlantBreeding, Bangladesh Institute of Nuclear Agriculture). Thereafter, the irradiated shoot cuttings were planted in polythene bags and kept under natural conditions. It was observed that callusing was initiated from 8th weeks after placement of tea shoot cuttings in the polythene bags and completed by 12th weeks. The morphological growth of tea shoot cuttings were recorded under varying levels of gamma radiation and growth stages. It was observed that the number of leaves, number of primary branches, base diameter, root length and total leaf area per plant significantly increased with the progress of time and increasing levels of gamma radiation, however, the plant height showed decreasing trend with the increasing levels of gamma radiation, which could be due to the change in chromosomal structure and genetic makeup. After 56 weeks of planting, the plant height, the number of leaves and primary branches per plant, base diameter, root length and total leaf area per plant recorded were 65.70 cm, 30.67, 7.33, 1.48 cm, 23.50 cm, and 1250.67 cm2 per plant respectively under the radiation level 60 Gy, whereas the corresponding figures of the above parameters at the control treatment were 76.21 cm, 18.33, 3.67, 0.92 cm, 17.75 cm and 778.33 cm2 per plant, respectively. A significant relationship was observed among the physiological growth parameters with the increasing levels of gamma radiation. The total dry matter gain, leaf area index, absolute growth rate and relative growth rate were significantly influenced with the rising levels of gamma radiation (up to 60 Gy), whereas the net assimilation rate of individual tea plant non-significantly responded as compared to those of control treatment. Finally after 56 weeks of planting, the maximum total dry weight gain, leaf area index, absolute growth rate, relative growth rate and net assimilation rate recorded under 60 Gay radiation level were 40.25 g/plant/week, 4.25, 1.18 g/week, 0.0621g/g/week and 17.07 g/m2/week respectively.

• 생물환경조절학회지
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• 제18권4호
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• pp.303-308
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• 2009

본 연구는 저압 조건에서 작물의 생장 가능성을 검토하고, 작물 생장에 미치는 압력의 영향을 살펴보고자 수행되었다. 공시작물인 적치마상추종자(Lactuca sativa L.)를 일반 대기압조건에서 발아시켜 인공혼합 배지를 채운 50공 플러그트레이 절반에 정식하였다. 정식된 상추묘는 3수준의 압력조건(25, 50, 101.3 kPa)에서 처리 되었다. 모든 처리조건에서 광주기 16/8 h, 기온 26/$18^{\circ}C$, 광합성유효광양자속 $240{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$으로 유지하였다. 3수준의 압력 조건에서 생장된 상추의 생장조사는 처리 후 7일과 14일째에 이루어졌다. 7일째 생장조사 결과 25, 50, 101.3 kPa 처리조건에서 엽수, 뿌리길이, 지상부 건물율, 엽색의 hue값은 유의차가 인정되지 않았다. 엽장, 엽폭, 엽면적, 지하부 건물중은 101.3 kPa의 처리조건보다 25, 50 kPa의 처리조건에서 유의차가 있는 것으로 조사되었다. 14일째 생장조사 결과 엽장, 지상부 건물율, 지하부 건물율은 25, 50 kPa의 처리 조건에서 유의차가 인정되었다 7일째 생장조사 결과와는 다르게 25, 50, 101.3 kPa의 처리조건에서 엽수, 엽폭, 엽면적, 뿌리길이, 지상부 생체중, 지상부 건물율, 엽색의 saturation 값의 유의차가 인정되지 않았다. 상기의 결과로부터 25, 50 kPa의 저압조건에서도 상추의 재배가 가능함을 확인하였다. 한편, 작물로부터의 증산과 배양액으로부터의 증발로 말미암아 저압 챔버내의 상대습도가 높은 수준으로 유지되었고, 이로 인하여 저압 챔버 내부 표면에 응축수가 발생되었다. 이러한 응축수는 저압 챔버 내부로 투과되는 광양을 저하 시키므로 작물의 생장에 부정적인 영향을 미치게 된다. 그러므로 저압 챔버 내의 높은 상대습도를 적절한 수준으로 제어할 수 있는 기술 개발이 요청된다.

• 생물환경조절학회지
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• 제4권2호
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• pp.152-158
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• 1995

고추의 양액재배에서 근권온도와 양액중 질소형태의 관계를 알아보기 위하여 3수준 (18$^{\circ}C$, 22$^{\circ}C$, 26$^{\circ}C$의 근권온도에서 양액중 질소형태의 비율을 달리하여 (NO$_3$-N/NH$_4$-N = 10:0, 8:2), 고추의 생육, 수량, 광합성속도, 엽록소 함유율 및 근의 활성에 미치는 영향에 대하여 검토하였다. 초장, 엽수, 경경과 엽, 근의 생체중 및 건물중은 근권온도에 의한 영향은 없었으나, NH$_4$-N의 첨가에 의하여 18$^{\circ}C$, 22$^{\circ}C$, $25^{\circ}C$의 모든 근권온도에서 초장, 엽수, 경경과 엽, 근의 생체중 및 건물중은 증가하였다. 고추의 과장은 18$^{\circ}C$와 26$^{\circ}C$의 근권온도에서 NH$_4$-N의 첨가에 의하여 약간 길어지는 경향이었고, 주당 과수 및 수량은 NH$_4$-N의 첨가에 의하여 모든 근권 온도에서 증가하였다. 광합성속도는 근권온도가 높아질수록 저하되었으나, NH$_4$-N의 첨가에 의하여 18$^{\circ}C$, 22$^{\circ}C$, 26$^{\circ}C$의 모든 근권온도에서 유의적으로 높아졌다. 엽록소 상대적함유량은 22$^{\circ}C$의 근권온도에서 높아졌으며, NH$_4$-N의 첨가에 의하여 18$^{\circ}C$, 22$^{\circ}C$, 26$^{\circ}C$의 모든 근권온도에서 높아졌다. 근의 활성은 26$^{\circ}C$의 근권온도에서 높아졌고, NH$_4$-N의 첨가에 의하여 18$^{\circ}C$, 22$^{\circ}C$, 26$^{\circ}C$의 모든 근권온도에서 높아졌다.

• 한국유기농업학회지
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• 제4권1호
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• pp.75-84
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• 1995

This study was carried out to find the effects of the mixtures of earthworm cast, peatmoss, and vermiculite as a vegetable plant growth medium on the growth pepper seedlings. The mixed ratios of earthworm cast-peatmoss-vermiculite were 40-20-40, 40-30-30, 40-40-40, 50-20-30, 50-30-20, 60-10-30, 60-20-20 and 60-30-10%. The results of the study are as follows: 1, There was a significant difference of plant length, leaf area, shoot dry weight, root dry weight and biological yield per plant for growth stages and mixed ratios(p<0.05). But there was no significant interactions for both of them. 2. The nursery soil with earthworm cast was generally higher than the control treatment in shoot dry weight, root dry weight adn biological yield per plant. The shoot dry weight and biological yield per plant were high in the treatment including 60% of the earthworm cast to the 3rd week and in the one including 50% from the 4th week. But in root dry weight, the treatment including 40% of it was higher than treatment of the others. 3. The shoot dry weight per plant in treatments consisting both of 40% of earthworm, 40% of peatmoss and 20% of vermiculite and of 60%, 10% and 30% was more significant than that in the control treatment(p<0.05). 4. The average relative growth rates of shoot dry weight, root dry weight and biological yield for all treatments were higher than the ratio of control treatment except the ration of the treatment consisting of 60% of earthworm, 20% of peatmoss and 20% of vermiculite.

• 한국토양비료학회지
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• 제15권3호
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• pp.156-161
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• 1982

인삼산지포장(人蔘産地圃場)에서 토양유기물함량(土壤有機物含量)은 토양수분(土壤水分)과 근수량(根收量)과 유의정상관을 보였다. 토양수분(土壤水分)은 근수량(根收量), 경직경, 경장, 유의정상관을, 지상부(地上部) 상대 결주율(缺株率), 낙엽율(落葉率), 반점병리병율(斑点病罹病率)과는 유의부상관을 보였다. 현(現) 재배법으로 칸당 2kg 이상(以上)의 수량(收量)을 내려면 토양수분(土壤水分)이 17% 이상(以上) 유기물(有機物)은 2%이상 이어야 할 것으로 나타났고 이에 미달(未達)인 포장(圃場)이 58% 였으며 이들은 대부분(大部分) 사양토(砂壤土)와 양토(壤土)였다.

• 생물환경조절학회지
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• 제30권1호
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• pp.56-64
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• 2021

본 연구는 옥신의 종류와 처리 농도가 온실 내 딸기(Fragaria × ananassa Duch. cv. Maehyang) 삽목묘의 발근과 생육에 미치는 영향을 알아보기 위해 수행되었다. 삽수는 NAD(1-naphthylacetamide), IAA(3-indoleacetic acid), 그리고 IBA(indole-3-butyric acid)에 각각 50, 100, 150, 및 200mg·L-1 농도로 1시간 동안 침지 처리되었다. 무처리는 대조구로 설정되었다. 삽수들은 2020년 6월 4일에 코이어가 충진된 딸기 육묘용 트레이에 삽목 되었다. 가습 처리는 2주 동안 처리되었다. 대조구, IBA, 및 IAA는 처리간 발근율에 있어 유의적인 차이가 없었다. 그러나 NAD 처리에서는 유의적으로 낮은 발근율이 관찰되었다. 생존율은 대조구와 IBA 50mg·L-1 처리에서 다른 처리에 비해 유의적으로 높았다. 엽수는 IBA 100mg·L-1 처리에서 가장 많았다. IAA 100과 150mg·L-1 처리에서 다른 처리에 비해 더 많은 주근 수가 관찰되었다. 지하부 건물중은 대조구에서 가장 무거웠다. 총 뿌리길이, 뿌리 표면적, 근단 수 및 뿌리 분기 수는 대조구에서 유의적으로 가장 높은 값을 보였다. 결과적으로, 대조구, IAA, 그리고 IBA 처리는 유사한 지상부와 지하부 생육을 보였다. 그러나, NAD 처리는 가장 좋지 않은 지상부와 지하부 생육을 보였다. 이를 고려하였을 때, NAD 처리는 IAA, IBA와 비교하여 딸기 삽목묘의 발근에 적절하지 않은 생장조절물질로 판단된다.

• Imaging Science in Dentistry
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• 제43권3호
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• pp.191-196
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• 2013

Purpose: This study assessed the accuracy of linear and angular measurements on panoramic radiographs taken at different positions in vitro. Materials and Methods: Two acrylic models were fabricated from a cast with normal occlusion. Straight and $75^{\circ}$ mesially and lingually angulated pins were placed, and standardized panoramic radiographs were taken at standard position, at an $8^{\circ}$ downward tilt of the occlusal plane compared to the standard position, at an $8^{\circ}$ upward tilt of the anterior occlusal plane, and at a $10^{\circ}$ downward tilt of the right and left sides of the model. On the radiographs, the length of the pins above (crown) and below (root) the occlusal plane, total pin length, crown-to-root ratio, and angulation of pins relative to the occlusal plane were calculated. The data were subjected to repeated measures ANOVA and LSD multiple comparisons tests. Results: Significant differences were noted between the radiographic measurements and true values in different positions on both models with linear (P<0.001) and those with angulated pins (P<0.005). No statistically significant differences were observed between the angular measurements and baselines of the natural head posture at different positions for the linear and angulated pins. Conclusion: Angular measurements on panoramic radiographs were sufficiently accurate and changes in the position of the occlusal plane equal to or less than $10^{\circ}$ had no significant effect on them. Some variations could exist in the pin positioning (head positioning), and they were tolerable while taking panoramic radiographs. Linear measurements showed the least errors in the standard position and $8^{\circ}$ upward tilt of the anterior part of the occlusal plane compared to other positions.

• 대한전기학회논문지
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• 제36권12호
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• pp.848-855
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• 1987

The currents in the rails of an electromagnetic railgun are concentrated in a near surface region. In order to understand this phenomenon, this paper deals with computation of the current distribution related to skin effect in a railgun. An analytical solution is obtained for a twodimensional model. It is found that current concentration at the interface between the rails and the armature is affected by the velocity, length and conductivity of the armature, that skin effect in the rails is affected by the relative velocity between the rails and the armature rather than other factors, and that skin depth in the rails is inversely proportional nearly to the square root of the velocity.

• 생명과학회지
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• 제11권2호
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• pp.153-158
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• 2001

To investigate the effects of soil acidification on growth of Impatiens balsamina L. plants were transplanted to acidified soils with H$_2$SO$_4$ solution. The concentrations of soluble Ca, Mg, K, Al and Mn in the acidified soils increased with increment of H$^{+}$ addition to the soil. In both species, the plant height and root length were inhibited by soil acidification, showing much severer inhibition in Impatiens balsamina L. than in Tagetes patula L., As the soil pH decreases, the growth of underground parts decreased greatly than that of above ground parts in both species. Total dry weight decreased with increased Al concentration as well as lowered soil pH in both plants. There was a strong positive correlation between relative total dry weight and molar (Ca+Mg+K) / Al ratio of the soil. The results suggest that molar(Ca+Mg+K)/ Al ratio of the soil may be useful indicator for assessing the critical load of acid deposition in herb species.s.

• 설비공학논문집
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• 제16권8호
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• pp.683-690
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• 2004

A modified rectangular fin is analyzed by two-dimensional analytic method and finite difference method. Relative error of heat loss from the modified rectangular fin between analytic method and finite difference method is presented. Comparisons of fin effectiveness and heat loss between a modified rectangular fin and a plane rectangular fin are made as a function of the non-dimensional fin length and wing height for different positions of wings by using analytic method. The ratio of the incremental rate of heat loss to that of the area of a modified rectangular fin is shown as a function of the wing height. One of the results shows that performance of a modified fin is more improved as the wing approaches the fin root.