• The Korean Journal of Ecology
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• 제17권3호
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• pp.241-249
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• 1994

참나무속 식물 6종류의 잎의 확산저항, 기공밀도, 공변세포의 길이 및 털의 밀도를 측정하여 건조스트레스에 대한 이 식물들의 전략을 주성분분석법으로 분석하였다. 상수리나무, 갈참나무 및 졸참나무의 잎의 확산저항은 다른 3종보다 높은 Ψleaf 또는 낮은 WSD에서 빠르게 상승함으로써 수분 스트레스를 회피하였다. 그러나, 신갈나무와 떡갈나무는 낮은 Ψleaf, 낮은 기공밀도, 작은 기공 크기 및 높은 털밀도로 수분스트레스를 회피하였다. 그러나 신갈나무와 떡갈나무는 낮은 Ψleaf에서 기공 확산저항의 상승을 보였다. 건조스트레스에 대한 조정능과 관련된 15변수의 주성분분석에서 참나무속 식물은 2그룹, 즉 건성생육지종인 굴참나무, 신갈나무 및 떡갈나무와 중성생육지종인 상수리 나무, 갈참나무 및 졸참나무로 구별되었고, 건성생육지종인 굴참나무는 높은 털밀도, 낮은 기공밀도 및 높은 LAR에서 신갈나무 및 떡갈나무와 다시 구별되었다. 이 결과는 자연생육지에서 참나무속 식물의 건조에 대한 전략을 잘 설명하고 있다.

• 한국지반공학회논문집
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• 제18권4호
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• pp.309-317
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• 2002

본 논문은 경량기포혼합토(LWFS)의 역학적 특성에 대하여 연구하였다. 경량기포혼합토는 단위중량의 감소와 압축 강도의 증가를 위하여 연안준설토, 고화제 및 기포를 혼합하여 제작되었다. 초기함수비, 고화제 함유율, 양생조건 및 구속압 등 다양한 조건으로 경량기포혼합토를 제작하여 일축 및 삼축압축시험을 실시하였다. 경량기포혼합토의 실험결과는 동일한 단위중량일 경우 응력-변형 거동과 압축강도는 준설토의 초기함수비보다 고화제 함유율에 더 영향을 받는 것으로 나타났다. 한편 삼축압축시험에서 응력-변형 관계는 양생조건에 관계없이 변형-연화거동을 나타내었다. 구속압에 따른 응력-변형 거동은 경량기포혼합토의 일축압축강도와 근접한 구속압을 경계로 다르게 변화하는 것으로 나타났다. 압축강도 200kPa 이상으로 지반개량을 하기 위해 요구되는 경량기포혼합토의 배합비는 준설토의 초기함수비 100%~160%와 고화제 함유율 6.6%로 나타났다.

• 대한한의학회지
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• 제28권3호통권71호
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• pp.183-196
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• 2007

Objective : This study was conducted in order to find the effects of Gammaekdaejo-tang (Ganmaidazao-tang, GDT) by subjecting rats to immobilization stress, thereby inducing depression, anxiety and acquisition-retention defects. Method : Rats treated with normal saline, GDT 200mg/kg and GDT 400mg/kg were subjected to stress by immobilization. Afterwards, behavior changes were observed by elevated plus maze test, acquisition test and retention test in the Morris water maze. The results were obtained by immunohistochemically measuring stress hormone (corticosteroid) levels in the blood. Results and Conclusions : 1. The open arm test in the elevated plus maze showed that compared with the normal group, the time spent decreased in the control group and increased in the GDT 400mg/kg group. 2. The locomotor activity test in the elevated plus maze revealed that the control group showed significant activity decrease compared with the normal group but significant increase in the GDT 400mg/kg group. 3. The acquisition test in the Morris water maze showed that the acquisitive ability of the control group significantly deteriorated on the 3rd and 4th day compared with the normal group, but improved significantly in the GDT 200mg/kg and GDT 400mg/kg groups. 4. The retention test on the 7th day in the Morris water maze revealed that the retentive ability of the control group significantly deteriorated compared with the normal group, but the retentive ability of the GDT 400mg/kg group significantly improved. 5. The blood levels of corticosteroid in the control group increased significantly compared with the normal group but the levels of corticosterone in the blood of the GDT 400mg/kg group significantly decreased.

• 아시안잔디학회지
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• 제3권1호
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• pp.24-33
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• 1989

This study was conducted to investigate the effect of paclobutrazol [(2 RS , 3 RS )1-(4- chlor-ophenyl )-4, 4- dimethyl -2- (1, 2, 4- triazol -1- yl )- pentan -3-01] on the tolerance of hi-gh temperature and drought stress as related to growth retardation , iranspiration rate , soil water content , nitrogen level and photosynthetic rate in perennial ryegrass ( Loliurn perenne L . ' Omega H , ). Plants were given a 30 ml soil drench of paclohutrazol at the concentrations of 0, 0.01, 0.1, 1.0, 10.. 0, mg / 6 .5cm- diameter pot . The rcsults were as follows : 1. Increasing concentrations of paclohutrazul reduced plant height , leaf area , fresh weight and dry weight , hut increased chlorophyll content per unit area . The number of tillers and leaf width were not affected hy the paclobutrazol concentrations . 2. The proper concentration of paclohatrazol on growth retardation in perennial ryegrass was about I mq /pot , hut leaf deformity and severe growth retardation were shown at high concentration of 10 mq / pot . 3. Perennial ryegrasses grown at 30˚C were shown significantly short plant height and low leaf nitrogen level compared with those grown at 20˚C. Increasing concentrations of paclohutrazol at 20˚C increased nitrogen level hut it could not increase nitrogen level at 30˚C . 4. During the drought stress , increasing temperatures significantly promoted transpiration rate and wilting time . It took about 5 days at 20˚C and 3 days at 30˚C to reach wilting time of leaves from water stress treatment . Soil water contents at wilting time of non-treated controls were averaged 6. 871% at 20˚C and 6. 17% at 30˚C 5. Paclohutrazol reduced transpiration rate at high temperature and drought stress . Wilting appeared at the lower water content of soil according to increasing concentrations of paclobutrazol at 30˚C hut there were no differences among concentrations of at 20˚C. 6.Paclohutrazol treatment at 1 rag /pot reduced injury rate of leaves from 67.1 % and 100 % in control plants to 15.7% and 80% at 20˚C and 3010, respectively. 7. Photosynthetic rate per unit area was significantly reduced at high temperature . Paclohutrazol stimulated photosynthetic rate with increase of concentrations at 20˚C but there was no increasing effect at 30˚C.

• Current Research on Agriculture and Life Sciences
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• 제15권
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• pp.93-100
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• 1997

4종(種)의 상치를 공시작물(供試作物)로 하여 수분(水分) 스트레스에 노출(露出)을 시켰을 때 총(總) 단백질(蛋白質)의 함량(含量)은 Flooding 처리시 그 감소율(減少率)이 더 크게 나타났으며 감소율(減少率)은 JCM이 가장 컸고, DCM이 가장 작았으며 품종간(品種間) 각 처리별(處理別) 차이(差異)가 크게나타났다. 총(總) 지질(脂質)의 함량(含量)은 감소율(減少率)이 CCM이 가장 컸고 JCM, DCM, DJM순(順)으로 감소(減少)하였다. 항산화효소(抗酸化酵素)인 Superoxide Dismutase(SOD)는 Catalase, Ascorbate Peroxidase의 활성도(活性度)는 전체적으로 감소(減少)하였으며 그 감소율(減少率)은 Catalase의 경우 처리별 JCM이 가장 크게 나타났고 DCM, DJM에서는 Flooding 처리시 효소의 활성도 변화가 더 크게 나타났다. Calatase의 활성도(活性度) 변화(變化)가 Ascorbate peroxidase의 활성도(活性度) 보다 감소율(減少率)이 더 크게 나타나 이는 Catalase가 Ascorbate peroxidase 보다 과산화수소(過酸化水素)와 더 직접적(直接的)으로 반응(反應)을 함을 나타낸다. Drought 처리기간별(處理期間別) 효소(酵素)의 활성도(活性度)는 생육시간(生育時間)이 길어질수록 감소(減少)하는 경향(傾向)이었으며 Catalase의 활성도(活性度)가 4일째 이후 가장 급격하게 감소(減少)하였다.

• 한국어병학회지
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• 제15권2호
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• pp.65-75
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• 2002

This study was performed to know the effects of stress induced by the daily fluctuation of water temperture from 18$^{\circ}C$ to 25$^{\circ}C$ up and down for 30 days on the defence mechanism of olive flounder. Puralichthys olivaceus. To make clear the temperature stress on the defense mechanism of the tested fish. several factors of immune response such as counting of leucocyte appearance in peripheral blood, phagocytic activity in whole blood cells, nitroblue tetrazolium(NBT) reduction, chemiluminescence(CL) response, and lysozyme activity were investigated at 28 days after giving the change of water temperature. The fish was controlled under the none feeding condition during experimental period. Mortality of the tested fish was rapidly increased up to 22% within the first one week of the experimental period without any additional stress factors. The number of neutrophil of peripheral blood in the tested group was significantly higher than the control group at the 2nd week. but the number of lymphocyte was significantly lower than the control group at the 1st and 3rd day of the experimental period. respectively. In the NBT reduction test, the activity of macrophage in the control group fish was the highest on the 7th day while that in the tested group was on the 3rd day. Also. the phagocytosis of tested group against formalin killed cells was retarded compared with the control. CL response of the tested group was significantly lower from 2nd to 5lh day of the experimental period than the control. 'The lysozyme activity of tested group was remained higher during the experimental period than the control. Even though the tested fish showed different results in some non-specific factors of immune respceses between tested and control group fish, olive flounder seems highly adaptable in repealed water temperature change in condition after one week under the given temperature fluctuation range.

• 한국어류학회지
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• 제19권2호
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• pp.93-100
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• 2007

금붕어(Carassius auratus)를 사용하여 수온변화에 따른 스트레스 반응에 대한 기초자료를 얻고자, 수온상승과 하강에 따른 혈액 성상 및 생리적 반응을 조사하였다. 수온은 $15^{\circ}C$로부터 급격하게 하강시켜 1시간이내에 $10^{\circ}C$로 사육수를 조절하였으며, 이후 자연적으로 수온이 상승하도록 조절하였다. 12시간째에 수온은 $15^{\circ}C$로 회복되어 24시간째까지 유지하였다. 이러한 수온자극 스트레스를 3일 연속하여 주었다. 혈장 cortisol, glucose 및 lactic acid에서 72시간까지 대조구보다 스트레스 실험구에서 유의적으로 높은 값을 보였다. 혈장 $Na^+,\;Cl^-$ 및 aspartate aminotransferase (AST)는 두 그룹에서 유의적 차이를 보이지 않았다. 본 연구결과 혈장 cortisol, glucose, lactic acid, hematocrit, red blood cell 및 hemoglobin에서 일반적인 스트레스 반응을 보였다.

• Journal of Nutrition and Health
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• 제28권4호
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• pp.291-297
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• 1995

This study aimed to verify the nutritional and curative effects of protein hydroysate in rats model with gastric ulcer induced by restraint and water-immersion stress. Sprague-Dawley, famale rats weighing approximtely 200g were forced in 5$\times$5$\times$15cm plexiglas cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hours. After stress 4 kinds of diets(10% casein, 20% casein, 10% casein hydrolysate, 20% casein hydrolysate) were given for 5 days. In the gastric ulcer rats model, the growth, gastric emptying rate, trypsin activity in gastrointestinal content, plasma total protein, albumin, $\alpha$-amino-N, UUN, creatinine and hydroxyproline of the urine and nitrogen retention were analyzed for nutritional effects of dietary nitrogen levels(10%, 20%) and sources (casein, casein hydrolysate). The results were as follows ; In gastric ulcer rats model, severeness of ulcer, plasma protein, gastric emptying rate, nitrogen retention rate were not different between 20% casein-fed group and 20% casein hydrolysatefed group. But 10% casein hydrolysate-fed group had more curative group. The casein hydrolysate diet-fed group was lower trysin activity in small intestianl content than the casein-fed group, at both casein level(10%, 20%). Finally at 20% levels, there was no difference between casein and casein hydrolysate diet, but 10% level, casein hydrolysate diet was more curative of ulcer than casein diet in gastric ulcer rat model. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.

• 한국군사과학기술학회지
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• 제8권3호
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• pp.124-130
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• 2005

In this paper, the effects of matrix hygrothermal aging and residual stress changes on $Avimid^{(R)}$ K3B/IM7 laminates in $80^{\circ}C$ water were studied. The factors causing the $80^{\circ}C$ water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses. After 500 hours fully saturated aging of the neat resin, the weight gain was 1.55% increase with the diffusion coefficient $7{\times}10^{-6}m^2/s$ and the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the $[+45/0/-45/90]_s$ K3B/IM7 laminates in $80^{\circ}C$ water, the weight gain was 0.41% increase with the diffusion coefficient $1{\times}10^{-6}m^2/s$ and the loss of the microcracking fracture toughness was 43.8% of the original toughness. To see whether the residual stress influenced the fracture toughness, two ply $[90^{\circ}/0^{\circ}]$ laminates were put in $80^{\circ}C$ water from 2 hours to 8 hours. The changes in residual stress in 8 hours are less than 3MPa. Because the 3MPa change is not sufficient to degrade the laminates, the main factor to degrade the microcracking fracture toughness was the degradation of the matrix fracture toughness.

• Geomechanics and Engineering
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• 제32권3호
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• pp.245-254
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• 2023

Through qualitative analysis and quantitative analysis, the contradictory conclusions about the stability of the settled goaf with two-layer coal seams subject to building load were obtained. Therefore, it is necessary to combine the additional stress method and numerical simulation to further analyze the foundation stability. Through borehole analysis and empirical formula analogy, the height of water-conducting fracture zone in No.4 coal and No.9 coal were obtained, providing the calculation range of water-conducting fracture zone for numerical simulation. To ensure the accuracy of the elastic modulus of broken gangue, the stress-strain curve were obtained by broken gangue compression test in dried state of No.4 coal seam and in soaking state of No.9 coal seam. To ensure the rationality of the numerical simulation results, the actual measured subsidence data were retrieved by numerical simulation. FISH language was used to analyze the maximum building load on the surface and determine the influence depth of building load on the foundation. The critical building load was 0.16 MPa of No.4 settled goaf and was 1.6 MPa of No.9 settled goaf. The additional stress affected the water-conducting fracture zone obviously, resulted in the subsidence of water-conducting fracture zone was greater than that of bending subsidence zone. In this paper, the additional stress method was analyzed by numerical simulation method, which can provide a new analysis method for the treatment and utilization of the settled goaf.