• 공업화학
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• 제17권1호
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• pp.82-86
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• 2006

일반 휘발유 및 LPG용 자동차와 각종 유량계기 등에 사용되는 국산 부표는 $150^{\circ}C$ 이상의 엔진오일에 장시간 띄워 놓으면 연료의 침투로 인하여 중량과 부피의 변화로 외관이 팽창하거나 조직이 이완된다. 본 연구에서는 고온에서도 중량 및 부피의 변화(3% 이내)가 적으며 내유성 및 내열성을 갖는 고온 엔진 오일용 발포부표 제조에 관한 연구를 수행하였다. 부표의 기본 재료인 NBR을 HNBR로 대체하여 제조한 TROF II-3은 고온($150^{\circ}C$)의 오일에 100 h 동안 띄워 놓은 경우에 2.90%의 중량 변화율과 2.56%의 부피 변화율을 나타내었다. 또한, 무게와 부피 변화는 NBR을 사용한 경우(TROF I-3)보다 $150^{\circ}C$에서 각각 10.81%, 3.08%로 더 작은 변화율을 나타내었다. TROF II-3은 고온의 오일에서 중량과 부피에 대한 변화가 작고 제품의 외관과 비중도 일정하게 유지되므로 고온의 엔진오일용 부표로서 적합한 것으로 판단된다.

• 한국식품영양과학회지
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• 제33권9호
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• pp.1566-1572
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• 2004

냉동 반죽 제조시 azodicarbonamide(ADA) 첨가량을 달리하여 만든 냉동 반죽의 물성에 미치는 영향인 farinogram, amylogram, extensogram을 비교 조사하였고, 냉동 반죽의 품질을 결정하는 2차 발효 시간, 빵 제품의 pH, 수분 함량, 비용적 및 경도에 미치는 영향을 -20$^{\circ}C$ 냉동고에서 제조 직후부터 12주까지 저장하면서 비교 조사하였다. ADA 첨가량이 증가할수록 farinogram에서 반죽의 흡수율, 안정도와 강력도는 증가하고, 흡수 시간과 약화도는 감소하였으며, amylogram에서 호화 개시 온도와 최고 점도는 증가하고, 최고 점도시 온도는 감소하였다. 또한 extensogram에서는 발효시간 45분에서 면적, 신장도와 저항비는 증가하고, 저항도는 감소되었다. 냉동 반죽 제빵법으로 만든 냉동 반죽은 같은 냉동 저장 기간에서 ADA 첨가량이 증가할수록 2차 발효시간, 수분 함량 및 경도 값은 감소하였으며, pH, 비용적은 증가하였다.

• 한국세라믹학회지
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• 제32권3호
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• pp.385-393
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• 1995

Akali-resistant porous glass was prepared by phase separation in Na2O-B2O3-SiO2 system containing ZrO2 and MgO. ZrO2 was added for alkali-resistance and MgO for anti-cracking during leaching. Optimal content of ZrO2 for alkali-resistance was 7wt% and devitrification by heat treatment resulted from further addition. Pore size and pore volume were decreased and specific surface area was increased with ZrO2 addition due to depression in phase separation. Addition of 3mol% MgO to mother glass containing 7wt% ZrO2 was effective for anti-crack during leaching. In this case, with phase separation at 55$0^{\circ}C$ and 5$25^{\circ}C$ for 20 hrs. crack-free porous glasses could be prepared. The relation between pore size r and heat treatment time t at 55$0^{\circ}C$ was D=25.58＋18.16t. According to measurement of gas permeability, the mechanism of gas permeation was Knudsen flow. N2 and He permeability of porous glass which was prepared by heat treatment at 55$0^{\circ}C$ for 20 hrs. were 0.843$\times$10-7mol/$m^2$.s.Pa and 2.161$\times$10-7mol/$m^2$.s.Pa respectively.

• Journal of Welding and Joining
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• 제15권6호
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• pp.96-104
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• 1997

The present study was aimed to correlate the microstructure and the hardness as well as the wear resistance of the metal-ceramic particulated composite layer on the pure Al plate. The composite layers were constructed by the addition of TiC particles on the surface of Al-Cu alloyed layers by PTA overlaying process. Initially, the Al-Cu alloyed layers were achieved by the deposition of Al-(25 ~ 48%) Cu alloys on the pure Al plate by TIG process. It was revealed that TiC particles were uniformly dispersed without any reaction with matrix in the composite layer. The volume fraction of TiC particles (TiC V F) increased from 12% to 55% with increasing the number of pass of composite layer. Hardnesses of (Al-48%Cu + TiC (3&4layers)) composite layer were Hv450 and Hv560, respectively, due to the increase of TiC V/F. Hardnesses of (Al-Cu + TiC) composite layers decreased gradually with insreasing temperature from 100$^{\circ}$C to 400$^{\circ}$C, and hardnesses at 400$^{\circ}$C were then reached to 1/5 - 1/10 of room temperature hardness depending on the construction of composite layers. The Specific wear of (Al + Tic) layer and Al-48%Cu alloyed layer decreased to 1/10 of the of pure Al, while the specific wear of (Al-48%Cu + TiC (4 layers)) composite layer exhibited 1/15 of that of steel such as SS400 and STS304.

• 전기화학회지
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• 제2권2호
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• pp.88-92
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• 1999

리튬이온전지용 $LiCoO_2$ 전극의 도전재료인 흑연과 블랙에 대하여 도전재료 함량에 따른 복합체 전극의 겉보기 밀도, 전해액 중에서 집전체로부터 전극복합체의 자기박리 및 전자전도 저항 특성을 조사하였다. $LiCoO_2$복합전극의 겉보기 밀도는 도전재료의 함량 증가에 따라 감소하였으며, 복합체 중 $LiCoO_2$ 단독의 겉보기 밀도는 보다 큰 감소를 나타내었다. $4.7\%w/w$ 이상의 super s black 도전재료를 사용한 전극은 propylene carbonate와 diethyl carbonate의 1: 1 체적비 혼합용매 중의 1 mol/I $LiPF_6$ 전해액 함침으로 자기박리하였으며, 흑연 도전재료에서는 자기박리가 없었다 복합전극의 전자전도에 대한 비저항은 도전재료의 함량 증가에 따라 감소하였으며, super s black도전재료 $2\~3\%w/w$ 함량의 비저항은 Lonza KS6흑연 도전재료 $12\%w/w$ 함량의 비저항과 유사하였다. 본 연구에서 나타낸 범위 내에서 super s black도전재료를 사용할 때 전극 복합체 중의 $LiCoO_2$밀도가 높아 고용량을 나타내었다.

• Journal of Welding and Joining
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• 제11권2호
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• pp.74-85
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• 1993

Effect of Si metal powders addition with the plasma transferred arc(PTA) overlaying process on characteristics of the alloyed layer in aluminum alloy(A5083) has been investigated. The overlaying conditions were 175-250A in plasma arc current, 500mm/min in travel speed, the 5-20g/min in powder feeding rate. Main results obtained are summarized as follows. 1)Sufficient size of molten pool on surface of base metal was required for forming an alloyed layer; in a fixed travel, the formation of alloyed layer with clear and beautiful surface depend upon the plasma arc current and powder feeding rate; the greater plasma arc current and the smaller powder feeding rate were, the better bead was formed. Optimum alloyed conditions by which an excellent alloyed bead obtained was 225A in plasma arc current. PTA process made it possible to form an alloyed layer with up to 67wt% Si. 2)Microstructure in the alloyed layer was in accord with prediction from the Al-Si phase diagram 3)The hardness of the alloyed layer increased in proportion to Si content. 4)As volume fraction of primary Si increased, the specific wearness of the alloyed layer was significantly improved. However, no further improvement was found when the volume fraction was greater than about 30%. 5)Utilizing the PTA process, a crack free alloyed layer with maximum hardness of about Hv 310 could be obtained.

• 한국식품영양학회지
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• 제29권6호
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• pp.889-898
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• 2016

This study was to evaluate the characteristics of bread and the rheology of flour dough containing sugar alcohols, after addition of fructose. In the farinogram tests, the addition of sugar alcohol changed the stability and mixing tolerance index. The stability and mixing tolerance index of farinogram increased as the amount of sugar alcohols increased. Amylograms revealed that the increase in gelatinization temperature and maximum viscosity of wheat flour dough with sugar alcohols was more than that of controls. Extensogram of dough with sugar alcohols exhibited higher extensibility and resistance. After fermentation treatment, the dough volumes prepared with only sorbitol and xylitol were lesser than those prepared after addition of fructose. The volume of loaf and specific volume of bread containing sugar alcohols with fructose significantly increased. The breads containing sugar alcohols showed greater taste, flavor and texture scores, for breads prepared with either sorbitol with fructose or xylitol with fructose, compared to breads without fructose. Overall preference scores by sensory evaluation of bread containing sugar alcohols with fructose were higher than bread with only sugar alcohols. These results indicate that the addition of fructose improves the flavor of bread containing sugar alcohols.

• 한국식품영양학회지
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• 제33권6호
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• pp.681-691
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• 2020

This study was conducted to evaluate the characteristics of bread and the rheology of flour dough containing chlorella powder(0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%). In the farinograph test, the addition of chlorella powder changed water absorption, development time and mixing tolerance index for making bread. As the amount of chlorella powder increased, the water absorption increased, mixing tolerance index and the development time decreased. In the extensograph test, the degree of extension and resistance was decreased with increasing of chlorella powder content. In the amylograph test, the maximum viscosity was slightly decreased with increasing of chlorella powder contents. The colors of L value in bread crumb was significantly decreased as the chlorella powder addition. After fermentation treatment, The dough with 2.5% chlorella powder showed the lowest dough raising power compared to the other doughs. The addition of the chlorella powder had significant effect on bread texture. The bread consisting of 0.5% chlorella powder showed the highest volume of loaf and specific volume. Therefore, high quality of bread can be achieved by adding chlorella powder.

• 한국식품저장유통학회지
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• 제8권4호
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• pp.434-441
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• 2001

본 연구에 세는 제빵용 소맥분의 손상전분 함량을 비교 분석하여 최적의 작업조건 설정과 제빵 품질을 향상시킬 목적으로 손상전분 함량을 각각 달리하여 반죽의 물리적 특성 및 제빵 적성을 검토하였다. DNS와 CWRS 및 SW 등의 소맥을 제분하여 손상전분 함량 6.5%, 8.2%, 9.0%, 9.5% 및 10.5%를 함유한 시료로 제조한 반죽의 물리적 및 이화학적 특성인 farinogram, extensogram, amylogram 등을 조사하였으며, 또한 제빵 적성 실험으로 rheometer를 이용하여 제빵의 경도 및 비용적과 관능검사 등으로 품질을 평가하였다. 제빵 적성 실험에서 손상전분 6.5%, 10.5%에서는 효소활성이 강하여 반죽이 연약해져 선택, 모양이 나쁘게 나타났으며, amylogram특성 실험 결과 최고 점도가 900 B.U인 손상전분 9.5%에서 빵의 부피, fermentation tolerance가 증가하였다. extensogram에서 신장 저항성(R)값이 45분, 90분, 135분으로 시간이 갈수록 R값이 현저하게 증가하는 손상전분 함량 9.0%와 9.5%함유된 밀가루의 반죽 공정이 쉽고 장시간 발효에 잘 견디며 좋은 조직의 빵이 생산되었으며, 종합적인 관능 평가에서도 조직이 부드럽고 기공이 균일하며 씹힘성, 부피감 및 향 등이 가장좋은 제빵으로 나타났다.

• 대한기계학회논문집
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• 제12권3호
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• pp.489-496
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• 1988

본 연구에서는 오스템퍼링 처리된 구상흑연주철의 오스템퍼링 처리온도와 유 지시간을 변화시킨 후 대기중의 건조미끄름마찰실험을 하여 내마멸특성을 검토하는 것 을 목적으로 하였다.