• Journal of Chest Surgery
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• 제21권3호
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• pp.425-446
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• 1988

After 24 hours of preservation under 15 mmHg perfusion pressure the recovery rates of isolated canine hearts were determined. Preservation was performed in a cold room maintained at 4*C with 4 different types of perfusates bubbled with a mixture of 95% 0y and 5% CO~ using a modified perfusion unit designed in our institute. The perfusates used were as follows; Group 1: Krebs-Henseleit solution, Group 2: Krebs solution added by albumin and PGE1. Group 3: Modified Wicomb*s solution, Group 4: Modified Collin*s solution. The extent of myocardial recovery was evaluated using a modified isolated carmine perfusion model by measuring heart rate, systolic arterial pressure, left atrial pressure[LAP] and cardiac output. In addition to the above hemodynamic parameters, biochemical and enzymatic assays from perfusates and electron microscopic changes of the myocardium were also studied. The results were as follows; 1] The heart recovery rates were 41.6%, 53.4% and 108.9% in groups 1, 2 and 3, respectively, and group 3 elicited the best result[p< 0.001]. The heart beat was never recovered in group 4. 2] Recovered systolic arterial pressures[mmHg] were 63.3% in group 1, 94.9% in group 2 and 94.3% in group 3. 3] LAPs[mmHg] were 20 in group 1, 13.5 in group 2 and 11.2 in group 3, which suggested that the best myocardial preservation was elicited in group 3[p< 0.05]. 4] Cardiac output, the sum of aortic stroke volume and coronary leakage, were 69.1% in group 2, and 90.7% in group 3, but these were not statistically significant[p=0.24]. No aortic stroke output was measured in group 1 and 4. 5] The degree of myocardial edema increase was 17.5` in group 1, 24.6% in group 2, 20.9% in group 3 and 55.3% in group 4. But there were no statistical differences in each group[p= 0.08]. 6] CPK-MB[U/L] levels were increased 750% and 332%[p< 0.05], glucose levels[mg/dl] 60.5% and 78.2% and SGOT[U/L] levels 523% and 333%, in groups 2 and 3, respectively. Biochemical and enzymatic assays could not be performed in group 1 and group 4, because of poor recovery of heart beat. 7] Electron microscopic findings in the myocardium of most groups revealed slight to moderate muscle cell and mitochondrial edema. But all these findings were within the limits of reversible change. From these above results, it is suggested that modified Wicomb*s solution seems to be the most useful physiologic salt solution for preservation of the heart. We propose that after further study and improvement, our portable continuous hypothermic perfusion system will contribute to the development of a better preservation method for donor hearts for human heart transplantation.

• 한국식품과학회지
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• 제47권5호
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• pp.645-651
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• 2015

본 연구는 설탕을 소비톨로 대체하여 저장성을 높인 저열량 시폰 케이크를 만들고자, 전체 설탕 함량 중 소비톨을 0, 30, 50, 70, 100%로 대체하여 시폰 케이크를 제조하고, 가장 적합한 소비톨 대체량을 제시하였다. 케익 반죽에 소비톨 첨가량이 증가할수록 비중은 낮아지고, 점도는 감소하였다. 이는 굽기 손실률과 구운 후의 케이크 부피에 영향을 미쳐, 대조군의 굽기 손실률이 낮고, 부피는 큰 것으로 측정되었고, 소비톨 함량이 증가할수록 굽기 손실률은 증가하고 부피는 감소하였다. 시폰 케이크를 실온($25^{\circ}C$)과 냉장($8^{\circ}C$) 온도에서 3일간 보관하면서 조직감을 측정한 결과 제조당일의 경도는 대조군에서 가장 높았고, 소비톨 대체량이 증가할수록 점차 감소하였다. 저장시간이 길어질수록 시료간 경도의 차이는 감소하였으며, 저장일수의 증가에 따른 경도의 변화는 적었다. 응집성의 경우, 제조당일 시료간에는 차이가 없었고, 저장 1일부터 3일까지 50% 대체군이 가장 낮은 값을 보였다. 시폰 케이크의 내부 단면을 관찰한 결과 대조군은 내부의 기공이 크고 부드러운 내면을 보였으나, 소비톨 첨가량이 증가할수록 기공이 작고 조밀한 결과를 보였다. 저장 중 시폰 케이크의 외부를 관찰한 결과, 냉장보관 케이크에서는 저장 15일까지 곰팡이가 발견되지 않았으나, 실온저장 5일차에는 100% 소비톨 대체군을 제외한 모두 시료에서 곰팡이가 발견되었으며, 저장 7일차에는 모든 시료에서 곰팡이가 발견되었다. 곰팡이의 양은 대조군에서 가장 많았고, 소비톨 대체량이 증가할수록 현저히 줄었다. 저장기간에 따른 생균수 집락수 결과, 냉장온도에서는 저장 7일까지 모든 시료에서 균수가 검출되지 않았으며 실온에서 보관 시에도 2일까지는 무의미한 생균수 집락수가 계수되었다. 저장 3일째부터 총균수는 유의적으로 증가하였으며 저장 4일째는 소비톨 70%와 100% 대체군, 저장 5일째는 100% 대체군만 안전한 계수 수준을 보였다. 관능검사 결과 대조군과 소비톨 30, 70% 대체군은 전반적 기호도 뿐 아니라 모든 항목에서 가장 높은 평가를 받았다. 이상의 모든 결과를 종합해 보았을 때, 소비톨 70%를 첨가하여 제조한 시폰 케이크는 열량 감소 효과뿐만 아니라 품질 특성 및 관능적 특성에서도 높은 선호도를 얻었고, 저장성 향상 효과도 크게 나타나 시폰 케이크 제조 시 가장 적합한 설탕 대체량으로 판단된다.

• 한국전기전자재료학회논문지
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• 제14권10호
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• pp.861-867
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• 2001

In this paper, in order to investigate the catalytic effect of the sludge exhausted from waterworks on NO$_{x}$ removal, we measure NO removal characteristics with and without sludge pellets in BaTiO$_3$-sludge packed-bed reactor of plate-plate geometry. NO initial concentration is 50 ppm balanced with air and a gas flow rate is 5ι/min. Gas temperature is changed from 25 to 10$0^{\circ}C$ to investigate the role of sludge pellet on removing active oxygen species and NO$_2$. BaTiO$_3$pellets is filled for coronal discharge at upstream of reactor and sludge pellets is filled for catalytic effect at downstream of reactor. The volume percent of sludge pellets to BaTiO$_3$pellets is changed from 0% to 100% and AC voltage is supplied to the reactor for discharging simulated gases. In the results, when sludge pellets is put at the downstream of plasma reactor, NO removal rate is slightly increased. However, NO$_2$and $O_3$ as by-products during NO removal is significantly decreased from 51ppm without sludge pellets to 5 ppm with sludge pellets and from 50 ppm without sludge pellets to 0.004ppm with sludge pellets, respectively. Therefore, NO$_{x}$(NO+NO$_2$) removal rate is increased up to 93%. It is thought that sludge pellet maybe react with active oxygen species and NO$_2$ generated by corona discharge in surface of BaTiO$_3$pellets, the then NO$_2$O$_3$as by-products are considerably decreased. When we increase gas temperature from room temperature to 10$0^{\circ}C$, NO removal rate is decreased, while NO$_2$ concentration is independent on gas temperature. These result suggest that the removal mechanism of active oxygen species and NO$_2$in sludge pellet is not absorption, but chemical reaction. Therefore we expect that sludge pellets exhausted for waterworks could be used as catalyst for NO$_{x}$ removal with high removal rate and low by-product.oduct.

• Journal of the Korean Wood Science and Technology
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• 제3권1호
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• pp.3-15
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• 1975

How to stabilize wood against shrinking and swelling in variable atmospheric moisture conditions is important to the wood-using industry and a challenge to research. Polyethylene glycol stabilize wood by bulking the fiber. PEG also serve as a chemical seasoning agent, suppress decay in high concentrations, and have slight effect on physical properties, gluing or finishing. The study designed to determine the effect of PEG-400 on the dimensional stabilization of local hardwoods for wood carvings that could supply a greatly expanding tourist trade and making curved furniture parts, lamp stands and other decorative objects, and possible gunstock. The species examined were 6 species, Seo-Namoo (Carpinus laxiflora), Cheungcheung-Namoo (Cornus controversa), Gorosae-Namoo (Acer mono), Karae-Namoo (Juglans mandshurica), Jolcham-Namoo (Quercusserrata) and Sanbud-Namoo (Prunus sargentii), used as block of 5cm thick radially to the grain, 7cm wide tangentially, and 70cm long parallel to the wood grain. All these test piecies were conditioned above the fiber saturation point before impregnation. The stabilization effects were determined for PEG-400 treated woods in a 50 percent solution for 20 days. The following conclusions were obtained. PEG retentions increased with treating time. It was more effective to treat at 60$^{\circ}C$ than at room temperature. In degree of PEG-400 impregnation on species, Cheungcheung-Namoo havinglow specific gravity had the highest retentions, 68.77% but the lowest, 56.33% was shown in Jolcham-Namoo with high specific gravity. Specific gravity of treated wood increased considerably with effectiveness of polymer loading. The increases in specific gravity were 5.36 to 13.16 percent. The highest was Jolcham-Namoo, the lowest Karae-Namoo. On the dimensional stability, a 40 percent of effectiveness of polymer loading was just as effective as 60 percent in reduction in water absorptivity (RWA), antishrinkage efficiency (ASE) and antiswelling efficiency (AE), and from over 60 percent they increased more rapidly. Also species response varied considerably. ASE was 30.12 to 69.97 percent tangentially and 27.86 to 56.37 percent radially, AE 34.06 to 73.76 percent tangentially and 30.11 to 70.12 percent radially, and RWA 42.31 to 65.32 percent. No differences in volume swelling among the 6 species were observed. Its values were ranged from 14.98 to 19.55 percent and also increased with PEG retentions. On the mechanical properties, the strengths very much decreased with PEG-400 loadings as shown in Figure 12; that were 11.41 to 22.90 percent in compression, 21.61 to 34.35 percent in bending and 22.83 to 36.83 percent in tensile strength. PEG retention in cell wall was less than 1 percent and the most of PEG were immersed in cell lumen. Except for Korae-Namoo, effectivenesses of polymer loading were as much high as 61.58 to 75.02 percent. This is believed to be due to the effect of PEG-400 on excellant dimensional stability of treated woods.

• 해양환경안전학회지
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• 제25권6호
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• pp.780-787
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• 2019

본 연구에서는 국내외 저탄소 녹색성장을 위한 대안으로서 수소에너지와 그 이용 기술에 대한 관심이 높아지는 추세에 발맞춰 무탄소 연료인 수소를 LNG 의 주성분인 메탄, 메탄-프로판, 메탄-프로판-에탄 동축류 확산화염 내에 첨가하여 화염형상 및 연소생성물에 미치는 영향을 확인하였다. 상온상압 조건의 확산화염에 수소를 단계적으로 첨가하여 실제 생성되는 연소생성물의 변화 추이를 가스 분석기를 이용하여 실험적으로 관찰하였고 확산화염의 형상은 디지털카메라를 이용하여 단계적으로 관찰 하였다. 실험결과에서 확산화염에 수소를 첨가함에 따라 질소산화물의 생성량이 선형에 가깝게 증가하는 경향을 보였다. 이것은 수소의 상대적으로 높은 단열화염온도와 빠른 연소속도가 Thermal NOx의 생성을 촉진했기 때문이다. 반면 이산화탄소의 생성량은 감소하는 경향이 나타났는데 수소를 첨가함에 따라 메탄, 메탄-프로판, 메탄-에탄-프로판의 혼합 확산화염에 포함되어있는 전체 탄소비율이 줄어들어 이산화탄소의 생성량이 감소한 것이다. 이는 선박에서 LNG-수소의 혼합 연료사용으로 인해 온실가스인 이산화탄소를 저감할 수 있는 하나의 방안으로 고려될 수 있다는 것을 의미한다.

• 마이크로전자및패키징학회지
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• 제18권4호
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• pp.55-61
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• 2011

n형 $Bi_2(Te_{0.9}Se_{0.1})_3$ 분말을 기계적 합금화 공정으로 제조하고 텅스텐 분말을 분산시켜 $550^{\circ}C$에서 30분간 가압소결 후, 텅스텐 함량에 따른 열전특성을 분석하였다. 텅스텐 분말을 분산시키지 않은 $Bi_2(Te_{0.9}Se_{0.1})_3$ 가압소결체의 상온 출력인자는 $21.9{\times}10^{-4}$ $W/m-K^2$ 이었으며, 1 vol% 텅스텐 분말의 분산에 의해 상온 출력인자가 $30.5{\times}10^{-4}$ $W/m-K^2$로 증가하였다. 텅스텐 분말을 분산시키지 않은 $Bi_2(Te_{0.9}Se_{0.1})_3$ 가압소결체는 상온에서 0.52의 무차원 성능지수를 나타내었으며, 1 vol% 텅스텐 분말의 분산에 의해 무차원 성능지수가 0.95로 크게 향상되었다.

• 한국환경보건학회지
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• 제46권2호
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• pp.224-231
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• 2020

Objective: The objectives of this study are to update the information on the characteristics of humidifier disinfectant (HD) usage with HD associated health problems and to discuss the role of HD exposure assessment in the national program to monitor health problems in patients with HD associated diseases. Method: A total of 201 HD associated patients who registered to undergo clinical examination at Kangbuk Samsung Hospital was interviewed to acquire their responses regarding several HD use characteristics, including type of HD brands used, HD use duration, average daily HD use hours, and the volume of the room in which HD was used. The responses of the HD associated patients to HD use-related questions were compared between responses in the lung injury investigation and this study. Results: The responses of HD associated patients in this study were found to be different from those in the lunginjury investigation. In particular, some of the patients who had not answered in the lung-injury investigation were able to answer thanks to assistance from the investigator in this study. For their responses regarding the name of the most commonly used HD brand, the number of patients who did not answer (N=11) was reduced to eight in this study. Significant changes in the responses of study subjects to questions related to HD use were achieved through the interview in this study. Conclusion: This study found significant changes in the responses regarding HD use characteristics. HD exposure assessment should be included in the program in order to allow surveillance of HD associated health problems.

• 한국산림과학회지
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• 제103권4호
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• pp.547-555
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• 2014

본 연구는 병풍쌈을 대상으로 종자의 전처리(상온건조, 저온건조, 수침처리를 각각 48시간 동안 실시)에 따른 차광처리별 발아특성과 유묘의 생장특성을 알아보고자 하였다. 실험은 전처리된 종자를 용기에 파종하여 차광시설(전광 및 35%, 50%, 75%, 95% 차광)에 각각 배치하여 진행하였다. 종자의 발아율은 25.7~61.1%의 범위로 조사되었으며 전광 내 수침처리구에서 61.1%로 가장 높게 나타났다. 병풍쌈 유묘의 초장생장은 95% 차광에서, 근원직경은 전광에서 가장 높은 것으로 조사되었다. 엽생장(엽면적, 엽장, 엽폭, 엽두께)과 뿌리생장(전체뿌리길이, 뿌리투영단면적, 뿌리표면적, 평균뿌리직경, 뿌리부피)은 전반적으로 35%~75% 차광에서 양호한 것으로 조사되었으며 95% 차광에서는 가장 저조한 생장을 보였다. 또한, 부위별(잎, 줄기, 뿌리) 및 전체 생중랑은 모두 50% 차광에서, 지상부(잎, 줄기)와 전체 건중량은 75% 차광에서 가장 높은 것으로 조사되었으며 95% 차광에서는 모든 부위에서 가장 저조한 생장을 보인 것으로 나타났다 따라서 본 실험의 결과를 종합하면, 병풍쌈의 종자는 수침처리하여 높은 광도에서 발아시킨 후 어느 정도의 차광처리(50%~75% 차광)를 하는 것이 용기 유묘생산에 보다 효과적일 것으로 판단된다.

• 공업화학
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• 제24권5호
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• pp.513-517
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• 2013

본 연구에서는 화재나 화생방전 시 비상대피에 사용되는 상용 방독면의 흡착소재인 첨착활성탄의 특성을 분석하고 일산화탄소(CO)의 흡착성능 및 산화반응을 조사하고자 하였다. 대표 제품 4개를 선정하여 BET/BJH 측정을 통해 각 활성탄소의 비표면적, 기공부피 및 기공크기를 비교분석하고 SEM/EDS와 XPS를 이용한 표면 성분분석을 수행하여 일산화탄소 제거 효율간의 관계를 연구하였다. 불순물 제거를 위한 전처리(heat-treatment) 후 망간(Mn)과 구리(Cu)가 주 금속으로 첨착되어 있는 화재용 시료에서는 업체에 관계없이 반응 초기에 일산화탄소의 흡착을 보였고 이후 활성 탄소 내에 첨착된 금속 촉매에 의해 최대 99%의 이산화탄소($CO_2$) 변환율로 높은 촉매활성을 보이며 산화반응이 진행되었다. 망간(Mn)을 함유하지 않은 화생방용 시료의 경우 이산화탄소로의 변환율은 최대 60%로서 화재용 시료에 비해 떨어짐을 관찰하였다. 화재용 시료의 전처리 유무에 따른 일산화탄소 반응성 조사에서는 전처리 후 기공 내 불순물 제거 효과로 상온에서 이산화탄소의 검출시간이 약 30 min간 지연되어 일산화탄소와 이산화탄소에 대해 모두 더 높은 제거율을 보임을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권2호
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• pp.164-167
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• 2004

This study was carried out to investigate in vitro fertilization and development of in vitro matured pig oocytes inseminated with the Duroc boar sperm by different sperm washing media after thawing of the 5 ml frozen straws. Immature follicular oocytes (30-40) were transferred into each well of a Nunc 4-well multidish containing $500{\mu}l$ mTCM199 maturation medium. The sperm rich portion of ejaculates was collected into a 250 ml insulated vacuum bottle and gradually cooled 22 to $24^{\circ}C$ over a 2 h period. Semen was centrifuged at 800 g for 10 min and the seminal plasma discarded. Sperm were esuspended in a lactose-egg yolk and N-acetyl-Dglucosamine (LEN) diluent to contain $1{\times}10^{9}$ sperm/ml and cooled to $5^{\circ}C$ over a 2 h period. Immediately before freezing, semen was rediluted with an equal volume of LEN+4% glycerol and packed into 5 ml straws. After thawing of the 5 ml straw, the 5 ml semen was diluted with 20 ml Beltsville thawing solution (BTS) at room temperature. Oocytes were inseminated with untreated (unwashed and nonpreincubated) or treated sperm (washed two times in BTS, mTLP-PVA and mTBM media, respectively and nonpreincubated) with $2{\times}10^{7}$ sperm concentration. Oocytes were coincubated for 6 h in $500{\mu}l$ mTBM fertilization. At 6 h after IVF, oocytes were transferred into $500{\mu}l$ NCSU-23 culture medium for further culture of 6 h. Sperm penetration, polyspermy and male pronuclear formation of oocytes at 12 h after IVF and developmental ability of oocytes at 48 h after IVF were evaluated. Sperm penetration rate, male pronuclear formation and rate of cleaved embryos were higher in the BTS, mTLP-PVA and mTBM treatments than the unwashed treatment (p<0.05). The rate of blastocysts from the cleaved oocytes (2-4 cell stage) were higher in the mTLP-PVA treatment than in the unwashed, BTS and mTBM treatments. In conclusion, we recommend the washing of frozen-thawed sperm with mTLP-PVA medium before in vitro fertilization of oocytes in mTBM medium.