• 한국포장학회지
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• 제17권1호
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• pp.13-17
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• 2011

반가공 상태의 절단마늘의 저장성을 향상시키는 적정 포장 조건을 찾기 위하여 기체 투과도가 다른 필름으로 밀착 포장하고 저장 중 품질을 비교하였다. 박피 후 2등분 절단한 마늘을 400 g 단위로 통기성 포장(대조구), $30{\mu}m$ 저밀도 폴리에틸렌(LDPE), $50{\mu}m$ 폴리올레핀 PD 900, $20{\mu}m$ 폴리올레핀 PD 941 필름으로 밀착포장하고 $1{\pm}1^{\circ}C$에서 52일 동안 저장하면서 포장 내 기체조성과 함께 마늘의 중량감소, 표면색도, 경도, 가용성 고형분 함량, 부패율을 측정하였다. 외기의 공기 조성인 통기성 포장을 제외한 밀봉 필름 포장에서는 저장 45일 후에 대체적으로 $O_2$ 농도는 1~5%로, $CO_2$ 농도는 12~21%로 형성되었다. 통기성 포장에서는 저장 45일째에 높은 곰팡이 부패 발생과 함께 급격한 중량감소가 나타났고 색택 변화도 심하였다. 모든 포장에서 저장 중, 경도는 감소하고 가용성 고형분 함량은 큰 변화가 없었다. 낮은 기체투과도로 인하여 포장 내에 낮은 $O_2$ 농도와 높은 $CO_2$ 농도를 보였던 PD 900 포장에서 짓무름 현상과 곰팡이 성장이 없이 52일 동안 저장될 수 있어서 가장 우수한 저장성을 나타내었다.

• 한국포장학회지
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• 제20권3호
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• pp.71-76
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• 2014

농가로부터 판매처까지의 유통단계에서 변화하는 온도 조건에 노출된 생표고버섯의 저장성향상을 확보하기 위해 개별포장과 2차 포장을 결합시킨 마스터 포장 시스템을 적용하였다. 온도가 저온으로 유지되는 수송과 저장 단계에서는 1차와 2차 포장의 결합 형태로 유통되고, 온도가 높은 판매단계에서는 외부 2차 포장을 해체한 후 1차 포장 조건에서 적절한 가스농도를 확보할 수 있는 개념으로 설계하고, 2차 마스터 포장 내에는 $Ca(OH)_2$의 이산화탄소 흡수제를 포함시켰다. 유통흐름 중에서 포장의 온습도와 기체조성을 측정하고, 마지막 단계인 판매처에서 포장을 개봉하여 버섯의 품질을 측정하였다. 공기조성을 유지하는 관행적인 통기성 천공 포장을 대조구로 함께 유통흐름을 거치게 하여 저장 후 품질을 비교하였다. 초기의 수송 및 저장 단계에서 적절한 저온조건이 유지되지 못한 것으로 나타났으나, 유통의 전체 과정에서 버섯 주위에 산소 농도 0.4~4.2%, 이산화탄소 농도 0.7~1.7%로 품질보존에 도움이 되는 기체조성이 유지되었다. 포장 전 예건처리가 버섯의 품질보존에 효과가 있는 반면에, 마스터 포장 시스템의 긍정적 효과는 비예건 버섯에 뚜렷이 나타났다. 보다 효과적인 버섯 품질보존을 위해서 예건 처리 및 온도관리와 함께 조화된 마스터 포장 시스템의 설계가 추가적으로 이루지고 검토될 필요가 있는 것으로 생각된다.

• 한국포장학회지
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• 제16권2_3호
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• pp.53-58
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• 2010

낱개 단위의 단감 포장에 대해서 선도유지에 적절한 내부 기체조성을 얻을 수 있는 포장조건을 얻기 위하여 $-1^{\circ}C$에 저장시에 포장 표면적과 과중이 포장 내부 기체조성에 미치는 영향을 살펴보았다. 약 230 g의 대과에서 과실과 바로 맞는 플라스틱 필름의 표면적($0.040\;m^2$)에서는 낮은 투과도 필름들은($35\;{\mu}m$ 혹은$40\;{\mu}m$ 두께의 LLDPE/PP 및 $30\;{\mu}m$ OPP) 산소가 고갈되는 혐기적인 기체조성을 유발시키고 장기저장 시에 갈변발생율을 높혔다. 약 210 g의 중과와 약 190 g의 중소과에서는 $35\;{\mu}m$ LLDPE/PP의 넓은 표면적이 높은 $O_2$와 낮은 $CO_2$를 형성시키고, 장기저장시에 높은 연화와 흑변의 발생을 가져왔다. 이와 달리, 작은 포장 표면적은 낮은 $O_2$와 높은 $CO_2$를 형성시키고 높은 갈변 가능성을 보였다. 생리장해를 줄이는 내부기체조성을 얻기 위해서는 과중, 포장필름 종류, 포장 표면적의 적절한 조합이 필요한 것으로 확인되었다.

• 한국표면공학회지
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• 제41권3호
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• pp.121-128
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• 2008

High strength 7xxx aluminum alloys have been applied to automotive bump back beam of the some limited model for light weight vehicle. The aluminum bump back beam is manufactured through extrusion, bending and welding. The residual stress given on these processes combines with the corrosive atmosphere on the road spreaded with corrosive chemicals to melt snow to occur the stress corrosion cracking. The composition of commercial 7xxx aluminum has Zn/Mg ratio about 3 and Cu over 2 wt% for better strength and stress corrosion cracking resistivity. But this composition isn't adequate for appling to the automotive bump back beam with high resistance to extrusion and bad weldability. In this study the composition of 7xxx aluminum alloy was modified to high Zn/Mg ratio and low Cu content for better extrusion and weldability. To estimate the resistivity against stress corrosion cracking of this aluminum alloy by slow strain rate test, the corrosion atmosphere and strain rate separate the stress corrosion cracking from conventional corrosion must be investigated. Using 0.6 Mol NaCl solution on slow strain rate test the stress corrosion cracking induced fracture was not observed. By adding 0.3% $H_2O_2$ and 0.6M $Na_2SO_4$ to 1M NaCl solution, the corrosion potential and current density of polarization curve moved to active potential and larger current density, and on the slow strain rate test the fracture energy in solution was lower than that in pre-exposure. These mean the stress corrosion cracking induced fracture can be estimated in this 1M NaCl + 0.3% $H_2O_2$ + 0.6M $Na_2SO_4$ solution. When the strain rate was below $2{\times}10^{-6}$, the stress corrosion cracking induced fracture start to be observed.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2000년도 국제심포지엄 및 제26차 추계학술발표회
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• pp.93-93
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• 2000

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.547-551
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• 1998

Reaeration coefficient is the physical absorption of oxygen from the atmosphere by water. It is the most important natural means by which a stream replaces the oxygen consumed in the biodegradation of organic wastes, and the rate constant describing this process is the reaeration coefficient, It. Reaeration coefficient is the dominant parameter affecting the use of water quality model. Therefore accurate estimation of the reaeration coefficient is essential for optimum water quality management. There is several method to estimate stream reaeration coefficient. In this study, it would be concluded that SI-peak method is of practical use when applied to small stream, and CRI method is adequate to large stream.

• 센서학회지
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• 제17권1호
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• pp.61-68
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• 2008

The sensing characteristics of new oxide sensing materials, NiO, NiO-YSZ and CuO, were evaluated at the temperature of $700^{\circ}C$ in 10 % $O_2$containing atmosphere. Through simultaneous response to $NO_2$ and NO, the sensing mechanism of oxide electrode was studied and the relation of EMF and NO/$NO_2$ concentrations was elucidated. Moreover, for highly sensitive NOx sensor, modified mixed potential sensor which has at least two oxide electrodes was proposed.

• 한국식품저장유통학회지
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• 제4권1호
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• pp.11-15
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• 1997

This experiment carried out to find the storage life according to the kinds of packaging material. Sheridan(Grape) which was fumigated SO2 were wrapped with polyethylenes(Bio-PE and PE) and stored at $0^{\circ}C$ under 90% RH modified condition. The resorts were summarized as follow. Natural weight loss was increased according to the storage time during the 135days storage that was only 1.0-1.7% in sealing section while 10% in non-sealing section. Abonrmal fruits were increased as the storage time was increased and it was 6.6-6.7% in sealing section while 100% in non-sealing during the 135days storage. Quality of appearance and taste are better in sealing section than non-sealing section and it was good in Bio-PE sealing section between packaging materials. Moistrue content was de creased as the storage range was increased and the decreasing rate of that during the storage was 4.9-5.2% in sealing section between treatments. During the storage range increased, the soluble solid degree was increased in non-sealing section but decreased in sealing section.

• 신재생에너지
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• 제4권1호
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• pp.11-18
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• 2008

In-situ lithiated NiO has been manufactured as a conventional cathode material of molten carbonate fuel cell (MCFC), however this material has a weakness for commercialization of MCFC because NiO is spontaneously dissolved into the electrolyte under MCFC operating conditions, resulting in short circuit between cathode and anode. In this research, therefore, $Co(OH)_2$-coated Ni powder was prepared by precipitation method with controlling pH at low temperature and atmospheric pressure. Modified cathode was fabricated by a conventional tape casting method and sintered at 700$^{\circ}C$ in a $H_2/N_2$ atmosphere, Based on characterization result, Pore size distribution and porosity was suitable for the cathode of MCFC. According to the result of dissolution, Ni solubility of modified cathode was 33% lower than that of conventional cathode. In addition, modified electrode showed a good performance from the single cell operation.

• 동아시아식생활학회지
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• 제11권3호
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• pp.190-195
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• 2001

The objective of this study consists in finding the ways to make soybean cake (which is made of soaked soybean flour containing protein and lipid) a scientific and practical food even more easily. This study took a measurement of the change of pH, organic acid, microorganism, retrogradation and so soon. observing soybean cake prepared with soybean flour containing 6% of soybean oil at room temperature(19$^{\circ}C$) in two types of packaging, that is to say, $CO_2$ modified packing(CMP) and liner low density poly ethylene(LLDPE) packaging. As storing time went by, packed soybean cake didn't appeared in 12 days, either. Using modified atmosphere packaging soybean cake showed higer pH as well as less organic acid than unpacked. In addition, mould method makes water - activity lower, and it Puts a curb on the development of aerobic perishable microorganism and the retrogradation of rice cake. Unpacked soybean cake showed higher values than CMP Soybean Cake with enthalpy of retrogradation and the longer storing period the greater retrogradation process. Thus, storing or circulation period can be increased effectively without chemical or physical treatment.