• 한국잡초학회지
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• 제32권2호
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• pp.139-143
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• 2012

본 연구는 한국잔디로 조성된 잔디밭에서 예초 직후에 prohexadione-calcium을 엽면 처리하여 잔디와 경합하는 클로버의 생장을 억제하는 효과를 구명하기위하여 수행되었다. 클로버의 엽병장과 엽면적은 prohexadione-calcium의 처리로 7주에도 무처리에 비하여 현저하게 억제되었고, 클로버의 생엽중도 무처리에 비하여 현저하게 억제되는 것으로 나타났다. 엽색도는 무처리에 비하여 prohexadione-calcium 처리구가 높아졌고, 처리 농도가 높아질수록 엽색도도 높아지는 것으로 조사되었다. 잔디밭에서 클로버를 방임할 때보다 prohexadione-calcium의 처리는 클로버의 피복율을 현저히 억제할 수 있었다.

• 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.

• 대한치과교정학회지
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• 제19권1호
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• pp.219-243
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• 1989

The purpose of this study was to evaluate the effects of the chincap therapy on the craniofacial structure in persons with skeletal Class III malocclusion. The patients selected for this study were treated with extra-oral chincap therapy only. Both control and treatment samples were obtained from Seoul National University Hospital where these longitudinal data were gathered. 55 treated patients and 14 control patients were studied. The mean ages at the 1st evaluation was 8 years 3 months in the treatment sample and 9 years 4 months in the control sample. The duration of chincap therapy was variable but averaged 2 years of treatment. Post-treatment observation procedeeded for 1 year 2 months. Active treatment and post treatment effects were evaluated. The results were as follows: 1. Neither significant restraint nor acceleration of growth was found in the cranial base and maxilla during treatment. 2. A distal rotation of the mandibular complex was seen. 3. Some amount of restraint of growth was found in mandibular body length, ramus height, mandibular length during treatment. 4. The genial angle was reduced. 5. After removal of the chin-cap, forward displacement of the mandible took place.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.245-247
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• 2007

Sn-base solder bump is mainly used in micro-joining for flip chip package. The quantity of intermetallic compounds that was formed between Cu pad and solder interface importantly affects reliability. In this research, micro-bump was fabricated by two binary electroplating and the intermetallic compounds(IMCs) was estimated quantitatively. When the micro Sn-Ag solder bump was made by electroplating, SiC powder was added in the plating solution for protecting of intermetallic growth. Then, the intermetallic compounds growth was decrease with increase of amount of SiC power. However, if the mount of SiC particle exceeds 4 g/L, the effect of the growth restraint decrease rapidly.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.193-197
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• 2001

The growth in concrete structures repair has prompted major efforts to develop high early strength concrete. The internal or external restraint of thermal shrinkage movements could thus generate tensile stresses in concrete structures if it is used rapid setting repair concrete. Restrained shrinkage and thermal stresses could produce microcracks in concrete which increase its permeability and accelerate its long-term deterioration under weathering and load effects. This study aims at evaluation and increase of the engineering properties of high early strength concrete using regulated set cement.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2010년도 춘계학술발표대회 초록집
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• pp.61-61
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• 2010

The purpose of this study is to prevent the unstable fracture at the FCA butt weldment of hatch coaming deck in the ultra large containership during service life. In order to do it, the behavior of the embedded crack at the weldment under design loading conditions was evaluated in accordance with BS7910. Here, the level of primary stress induced by ship motion was evaluated by the design code of classification society and FEA. The level of residual stress as secondary stress was calculated in consideration of the restraint degree of weldment and welding heat input by using the predictive equation proposed by authors in the previous study. The fatigue crack growth rate at the weldment was evaluated using CT specimen in accordance with ASTM E647. According to the results, although the allowable defect for embedded crack specified in the classification society exists at the weldment, the occurrence possibility of unstable fracture at the weldment could not be negligible, regardless of CTOD value given in this study. So, in this study, the effect of initial defect size, welding heat input, restraint degree and CTOD on the fracture mechanical characteristics of embedded crack at the weldment was evaluated by the comprehensive fracture assessment. Based on the results, the design criteria including allowable defect, residual stress level and CTOD value was established to prevent the unstable fracture at the FCA butt weldment of hatch coaming deck in an ultra large containership during service life of 20years.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.431-437
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• 1998

This study was performed to ascertain the three-dimensional effect of the crack reduction and the restrained effect of crack growth, and to yield a suitable mixing ratio of the synthetic fiber reinforced soil. The results of the study are as follows ; 1) The synthetic fiber has the resisting force for crack because of the adhesion due to the attraction of soil particles. 2) As the synthetic fiber length and the mixing ratio are increased, mono filament synthetic fiber reinforced soil is increased the effects of crack reduction and the restraint of crack growth. 3) The fibrillated synthetic fiber is more effective than mono filament synthetic fiber for crack. 4) A suitable mixing ratio of synthetic fiber reinforced soil is 0.5% of the fibrillated synthetic fiber.

• Asian-Australasian Journal of Animal Sciences
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• 제3권2호
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• pp.125-133
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• 1990

The effect of dietary protein-energy restriction (PER) on the growth of long bone were examined in sheep during growing period and then following a cycle of reproduction. Three months-old female sheep were offered protein-energy restricted feed for 6 months (growing period), thereafter changed to normal nutritional conditions for 8 months (reproduction period). A half of animals in each group took pregnancy, parturition and lactation. The nutritional restriction reduced the growth in bone diameter more than that in bone length. Compensatory growth resulting from the removal of the nutritional restraint strongly occurred in bone diameter, especially the bone cortical width, as compared to bone longitudinal growth. A cycle of reproduction severely decreased the growth in the bone cortical width relative to that in the bone width, and little effect was found on the growth in bone length and bone mass. The depression of bone development by pregnancy and lactation tended to exhibit severer in animals having received normal nutrition than in those having received PER. Bone mineral density was not affected by the nutritional restriction. A cycle of reproduction had an adverse effect on the mineral density between in animals having received normal nutrition and in those having received PER.

• Smart Structures and Systems
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• 제18권1호
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• pp.75-92
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• 2016

The design of a semi-active (SA) control system addressed to mitigate wind induced structural demand to high wind turbine towers is discussed herein. Actually, the remarkable growth in height of wind turbines in the last decades, for a higher production of electricity, makes this issue pressing than ever. The main objective is limiting bending moment demand by relaxing the base restraint, without increasing the top displacement, so reducing the incidence of harmful "p-delta" effects. A variable restraint at the base, able to modify in real time its mechanical properties according to the instantaneous response of the tower, is proposed. It is made of a smooth hinge with additional elastic stiffness and variable damping respectively given by springs and SA magnetorheological (MR) dampers installed in parallel. The idea has been physically realized at the Denmark Technical University where a 1/20 scale model of a real, one hundred meters tall wind turbine has been assumed as case study for shaking table tests. A special control algorithm has been purposely designed to drive MR dampers. Starting from the results of preliminary laboratory tests, a finite element model of such structure has been calibrated so as to develop several numerical simulations addressed to calibrate the controller, i.e., to achieve as much as possible different, even conflicting, structural goals. The results are definitely encouraging, since the best configuration of the controller leaded to about 80% of reduction of base stress, as well as to about 30% of reduction of top displacement in respect to the fixed base case.

• 콘크리트학회논문집
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• 제22권1호
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• pp.69-76
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• 2010

콘크리트의 수축으로 인한 균열가능성 평가에 있어서 대부분의 경우 콘크리트를 균질한 물질로 가정하는 방식으로 접근하고 있다. 그러나 이러한 방식으로 접근할 경우 불구속조건 하의 콘크리트에서 자기수축으로 인한 미세균열(micro-cracking) 현상을 평가하는 것이 불가능함과 동시에 콘크리트 내부의 균열 발생 현상을 이해하는데 한계가 있다. 이에 이 연구에서는 시멘트 모르타르 시험체를 가지고 실험적으로는 음향방출(acoustic emission) 장비를 사용하여 내부 균열 발생량을 측정 및 평가하였으며, 이론적인 접근방식의 일환으로 실제 모르타르 시험체로부터 구하여진 이차원 이미지를 사용하여 NIST에서 개발한 OOF code로 유한요소해석을 수행하였다. 실험 및 해석 결과, 모르타르의 내부에서 시멘트 페이스트상의 수축 및 골재의 내부구속으로 인하여 발생하는 미세균열 발생 현상을 보다 현실적으로 이해할 수 있었다.