• Current Research on Agriculture and Life Sciences
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• 제20권
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• pp.71-76
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• 2002

경북대학교 부속과수원에 재식되어 있는 봉옥, 기원방, 청도반시, 나주파시 품종의 휴면중인 1년생 가지를 2002년 1월에 채취하여 저온에 대한 내성을 검토한 결과 다음과 같은 결론을 얻었다. 1. 눈의 갈변도 측정에서는 $-15^{\circ}C$에서의 저온에 의한 갈변의 정도가 컸으며, 품종별의 차이는 나주파시의 경우 $-5^{\circ}C$일때의 저온에 대한 갈변의 정도와 $-15^{\circ}C$때와의 차이가 별로 없으며, 그 수치도 딴 품종에 비해 적었다. 2. 목질부의 갈변도 측정에서는 눈의 갈변도와 같은 경향으로 $-15^{\circ}C$일 때 피해가 컸으며, 품종별의 차이는 청도반시의 목질부에 대한 저온에 의한 갈변의정도가 딴 품종에 비해서 높았다. 3. 감의 주요 품종의 전기전도도를 보면 $-15^{\circ}C$일 때 전체적으로 저온의 피해가 컸으며, 나주파시와 봉옥의 경우 저온처리가 $-10^{\circ}C$이하일 경우에 E.C. 값이 다른 품종보다 눈에 띄게 큰 것으로 보아 이 품종은 저온에 대한 내성이 약하다는 것을 알 수 있다. 4. 눈의 맹아율은 $-15^{\circ}C$에서도 맹아가 되었으나 $-15^{\circ}C$일때의 맹아율이 타 온도보다 많이 적었는데, 나주파시의 맹아율이 가장 낮았으며, 기원방의 맹아율은 타품종에 비해 많이 높았다. 5. 위의 실험의 토대로 품종별 내한성의 차이를 전체적으로 비교한 결과 나주파시와 봉옥이 다른 품종보다 내한성이 낮으며, 기원방이 다른 품종보다 내한성이 높게 나타났었다.

• 한국포장학회지
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• 제28권3호
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• pp.157-163
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• 2022

본 연구에서는 전자레인지 조리 시 발생하는 포장 내부의 수증기를 스스로 방출할 수 있는 PLA 기반 스마트 복합 필름을 제조하였다. 제조된 복합필름의 전자레인지 조리가 가능한 HMR 제품의 포장재로써 적용가능성을 평가하기 위해 DSC, UTM, GTR 및 전자레인지 모의 적용 평가를 통해 열적 특성, 기계적 특성, 온도 구간별 기체 투과도 및 전자레인지 적용성을 평가하였다. 복합필름의 열적 특성을 확인한 결과, PLA와 PEG의 강한 화학적 상호작용을 확인하였고 본 연구에서 기대한 전자레인지 조리 온도 내에서 PEG가 용융되는 것을 확인하였다. 또한, 제조된 복합필름은 PEG의 첨가로 인해 인장강도는 감소하였지만 연신율이 증가하였고, nanoclay의 함량이 증가함에 따라 감소된 인장강도가 일부 회복한 것을 확인하였다. 또한, 기체투과도의 경우 PEG의 T_m1 이상인 65℃ 부터 PEG가 용융되면서 투과도가 비약적으로 증가한 것을 확인하였다. 전자레인지 모의 적용 평가를 통해 pure PLA는 내부 수증기를 방출하지 못하고 그 압력을 버티지 못해 폭발한 것에 비해, 복합필름의 경우 전자레인지 수증기 발생 온도에서 그 형태를 유지하며 효과적으로 내부 수증기를 자가방출한 것을 확인하였다. 이러한 결과를 바탕으로 본 연구에서 제조한 스마트 복합필름은 포장재로써 향후 전자레인지 조리 HMR식품 포장재로써 적용될 수 있다.

• 한국지반신소재학회논문집
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• 제7권2호
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• pp.7-13
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• 2008

토목공사를 수행함에 있어 토목섬유가 적용된 이후 토목섬유의 손상에 대하여 많은 관심이 되어왔다. 토목용 섬유제품인 지오텍스타일은 주변 환경조건에 노출되는 고분자 재료로서 분리, 보강, 여과, 배수 등의 기능을 가지며 현재 제방공사, 해안 하천의 호안공사, 간척공사 또는 도로, 철도 노상 안정 등의 분야에 광범위하게 이용되고 있다. 본 연구는 토목섬유매트의 현장 적용시 설계방법을 분석하였고, 설계시 고려되는 인장, 파열, 꿰뚫림, 인열강도의 관계와 더불어 인장강도와 봉합강도의 상관성에 대하여 평가하였다. 또한, 토목섬유매트 적용시 유효봉합율과 시험방법의 적정성, 경제성 등이 고려된 시공방법론 등을 제시하였다.

• 한국포장학회지
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• 제11권2호
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• pp.91-96
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• 2005

Determination of safety factor of corrugated fiberboard boxes used for agricultural products is very complicated process due to nature of living products. Moisture content is one of the most critical factors to determine overall physical strength of paper, so its influences on strength properties of corrugated board made from different raw materials must be quantified. The results obtained from the study were summarized as follows; 1. Results show a detrimental effect on bursting strength and compressive strength of liners with increasing relative humidity of environment and moisture content of liners. 2. The relevance of equilibrium moisture content at varying relative humidity levels was proved and its relationship was used as an important factor to estimate box compression strength. 3. Test results was statistically used for establish the relationship between relative humidity and moisture content of liners. Estimated compression strength of boxes at varying moisture content was similar to results of theoretical equations such as Kellicutt's. Further study could be carried out in order to determine a optimum safety factors of various corrugated board boxes for agricultural products.

• 한국정밀공학회지
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• 제17권4호
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• pp.22-28
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• 2000

By using the finite element method, the Oyane's ductile fracture integral I was calculated from the histories of stress and strain according to every element and then the forming limit of hydroforming process could be evaluated. The fracture initiation site and the forming limit for two typical hydroforming processes, tee extrusion and bumper rail under different forming conditions are predicted in this study. For tee extrusion hydroforming process, the pressure level has significant influence on the forming limit. When the expansion area is backed by a supporter and bulged, the process would be more stable and the possibility of bursting failure is reduced. For bumper rail, the ductile fracture integral i is not only affected by the process parameters, but also by the shape of preforming blank. Due to no axial feeding on the end side of the blank, the possibility of cracking in hydroforming of the bumper rail is influenced by the friction condition more strongly than that of the tee extrusion. All the simulation results show reasonable plastic deformation, and the applications of the method could be extended to a wide range of hydroforming processes.

• 한국임상수의학회지
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• 제16권1호
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• pp.182-188
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• 1999

This study was performed to determine the causes of the bursting casualties such as death of sows and piglets, abortion, still birth and infertility in a pig farm after consecutive detonation for three months to construct 345 KV in Kimje area. 1. Temperatures in Kimje district, management condition, microorganism in the feed, inbreeding, hematological conditions, and viral agent causing abortion were not proved as the factors of acute occurrence of abortion and infertility in the pig farm. 2. The amount of explosive was increased from 250 kg to 1,100 kg from 23 Dec. 1996 to 28 Jan. 1997 and at the same time the distance between the spot of detonation and the pig farm got closer, from 200 m at the begining to 100 m at the last detonation. 3. Theoretical concussion and sound values were 0.66 kine and 89.39 ㏈, respectively, in the case of 100 m distance between the detonation spot and the pig farm. In conclusion, death of 675 piglets and 11 sows and infertility of 69 sows in the pig farm were assumed to be caused by the concussion or sound stress after detonation.

• 펄프종이기술
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• 제46권1호
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• pp.29-38
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• 2014

Guar gum is added to the pulp suspension at the suction side of the fan pump just before the sheet is formed on either a fourdrinier or cylinder machine. Guar gum replaced and supplements these hemicelluloses in paper bonding with many advantages, which include improved sheet formation with a more random distribution of pulp fibers. But, guar gum has serious storage problem. This material has easily decayed after High-temperature conditions such as summer. In this study, various properties of cotton handsheet were measured to solve the problem of deformation while storing guar gum and to improve the durability. After aging, which is one of the durability tests, cotton handsheet with 0.2% and 0.3% of A-PAM showed improved mechanical properties and bursting index and folding endurance of cotton handsheet with 0.3% of A-PAM were similar to those with guar gum. The yellowness loss of cotton handsheet with synthetic polymers was lower than those with guar gum.

• 한국정밀공학회지
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• 제20권1호
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• pp.205-213
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• 2003

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. It has two main merits which are to cut down energy by reducing weight and to prevent explosive damage preceding to the sudden bursting which is generated by the pressure leakage condition. Therefore, Pressure vessels using this composite material in comparison with conventional metal vessels can be applied in the field such as defense industry, aerospace industry and rocket motor case where lightweight and the high pressure are demanded. In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding composite pressure vessel receiving an internal pressure, the standard interpretation model is developed by using the ANSYS, general commercial software, which is verified as the accuracy and useful characteristic of the solution based on Auto LISP and ANSYS APDL. Both the preprocessor for doing exclusive analysis of filament winding composite pressure vessel and postprocessor that simplifies result of analysis have been developed to help the design engineers.

• 콘크리트학회논문집
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• 제11권5호
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• pp.69-77
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• 1999

A spalling is defined as the damages of concrete exposed to high temperature during the fire by causing cracks and localized bursting of small pieces of concrete. It is reported that spalling is caused by the vapor pressure and polypropylene(PP) fiber has an important role in protecting from spalling. This paper is a study on the properties and spalling resistance of high-performance concrete with the kinds of aggregate and the contents of PP fiber. According to the experimental results, concrete contained no PP fiber take place in the form of the surface spalling and the failure of specimenns after fire test regardless of the kinds of aggregate. Concrete contained more than 0.05% of PP fiber with the aggregate of basalt does not take place the spalling, while the concrete using granite and limestone does the surface spalling. It is found that residual compressive strength after exposed at high temperature has 50~60% of its original strength. Although specimens after exposed at high temperature is cured at water for 28days, they do not recover their original strength.

• Journal of Korean Neurosurgical Society
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• 제58권3호
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• pp.291-293
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• 2015

Anterior communicating artery (ACoA) aneurysms sometimes present with visual symptoms when they rupture or directly compress the optic nerve. Giant or large ACoA aneurysms producing bitemporal hemianopsia are extremely rare. Here we present an unusual case of bitemporal hemianopsia caused by a large intracranial aneurysm of the ACoA. A 41-year-old woman was admitted to our neurosurgical department with a sudden-onset bursting headache and visual impairment. On admission, her vision was decreased to finger counting at 30 cm in the left eye and 50 cm in the right eye, and a severe bitemporal hemianopsia was demonstrated on visual field testing. A brain computed tomography scan revealed a subarachnoid hemorrhage at the basal cistern, and conventional cerebral catheter angiography of the left internal carotid artery demonstrated an $18{\times}8mm$ dumbbell-shaped aneurysm at the ACoA. Microscopic aneurysmal clipping was performed. An ACoA aneurysm can produce visual field defects by compressing the optic chiasm or nerves. We emphasize that it is important to diagnose an aneurysm through cerebrovascular study to prevent confusing it with pituitary apoplexy.