• 열처리공학회지
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• 제34권1호
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• pp.10-16
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• 2021

Exhaust manifold is a very important component that is directly connected to air environment pollution and that requires strict mechanical properties such as high temperature fatigue and oxidation. Among stainless steels, the ferritic stainless steel with body-centered cubic structure shows excellent resistance of stress-corrosion cracking, ferromagnetic at room temperature, very excellent cold workability and may not be enhanced by heat treatment. The microstructural characteristics of four cast ferritic stainless steels which are high heat-resistant materials, were analyzed. By comparing and evaluating the mechanical properties at room temperature and high temperature in a range of 400℃~800℃, a database was established to control and predict the required properties and the mechanical properties of the final product. The precipitates of cast ferritic stainless steels were analyzed and the high-temperature deformation characteristics were evaluated by comparative analysis of hardness and tensile characteristics of four steels at room temperature and from 400℃ to 800℃.

• 한국가금학회지
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• 제41권2호
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• pp.77-85
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• 2014

본 연구는 소시지 제조 시 오리고기와 돼지고기의 혼합비율에 따른 냉장 저장 중 품질 특성을 구명하고자 수행하였다. 처리구는 소시지 제조 시 사용되는 고기 함량을 기준으로 오리고기 100%(T1), 돼지고기 100%(T2), 오리고기 50% + 돼지고기 50%(T3), 오리고기 40% + 돼지고기 60%(T4) 및 오리고기 30% + 돼지고기 70%(T5)로 나누었다. 그 결과, 수분은 다른 처리구에 비해 T1이 유의적으로(p<0.05) 가장 높았고, T2가 유의적으로(p<0.05) 가장 낮게 나타났다. 단백질과 지방함량에 있어서는 T2가 다른 처리구에 비해 유의적으로(p<0.05) 가장 높게 나타났다. 명도의 경우, T1이 전 저장기간 동안 다른 처리구에 비해 유의적으로(p<0.05) 가장 낮은 명도를 보였다. 적색도는 다른 처리구에 비해 T1이 전 저장기간 동안 유의적으로(p<0.05) 가장 높게 나타난 반면, T2는 전 저장기간 동안 유의적으로(p<0.05) 가장 낮은 것으로 나타났다. 경도의 경우, 오리고기 40%와 돼지고기 60%로 제조한 T4가 다른 처리구에 비해 전 저장기간 동안 유의적으로(p<0.05) 높게 나타났다. 응집성의 경우, 냉장 저장 2주까지 T5가 다른 처리구에 비해 유의적으로(p<0.05) 높게 나타났다. 관능평가 결과, 육향, 맛 및 조직감에 있어서는 T5가 유의적으로(p<0.05) 낮은 것으로 나타난 반면, 다른 처리구 간에는 유의적인 차이가 없는 것으로 나타났다. 전체적인 기호도는 T5가 다른 처리구에 비해 유의적으로(p<0.05) 낮은 것으로 나타났다. 이상의 결과를 종합해 볼 때, 오리고기 소시지 제조 시 경도와 기호성을 좋게 하기 위한 근육 단백질의 혼합 비율은 오리고기 40%와 돼지고기 60%의 비율이 적당한 수준인 것으로 사료된다.

• Journal of Welding and Joining
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• 제33권5호
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• pp.53-60
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• 2015

Laser surface Melting Process is getting hardening layer that has enough depth of hardening layer as well as no defects by melting surface of substrate. This study used CW(Continuous Wave) Yb:YAG and STD11. Laser beam speed, power and beam interval are fixed at 70mm/sec, 2.8kW and 800um respectively. Hardness in the weld zone are equal to 400Hv regardless of melting zone, remelting zone overlapped by next beam and HAZ. Similarly, microstructures in all weld zone consist of dendrite structure that arm spacing is $3{\sim}4{\mu}m$, matrix is ${\gamma}$(Austenite) and dendrite boundary consists of ${\gamma}$ and $M_7C_3$ of eutectic phase. This microstructure crystallizes from liquid to ${\gamma}$ of primary crystal and residual liquid forms ${\gamma}$ and $M_7C_3$ of eutectic phase by eutectic reaction at $1266^{\circ}C$. After solidification is complete, primary crystal and eutectic phase remain at room temperature without phase transformation by quenching. On the other hand, microstructures of substrate consist of ferrite, fine $M_{23}C_6$ and coarse $M_7C_3$ that have 210Hv. Microstructures in the HAZ consist of fine $M_{23}C_6$ and coarse $M_7C_3$ like substrate. But, $M_{23}C_6$ increases and matrix was changed from ferrite to bainite that has hardness above 400Hv. Partial Melted Zone is formed between melting zone and HAZ. Partial Melted Zone near the melting zone consists of ${\gamma}$, $M_7C_3$ and martensite and Partial Melted Zone near the HAZ consists of eutectic phase around ${\gamma}$ and $M_7C_3$. Hardness is maximum 557Hv in the partial melted zone.

• 한국재료학회지
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• 제22권11호
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• pp.591-597
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• 2012

For heat exchanger applications, 2-ply clad materials were fabricated by rolling of aluminum (Al) and mild steel sheets. Effects of annealing temperature on interface properties, especially on inter-layer formation and softening of strain hardened mild-steel, for Al/mild steel clad materials, were investigated. To obtain optimum annealing conditions for the Al/mild steel clad materials, annealing temperature was varied from room temperature to $600^{\circ}C$. At the annealing temperature about $450^{\circ}C$, an inter-layer was formed in an island-shape at the interface of the Al/mild steel clad materials; this island expanded along the interface at higher temperature. By analyzing the X-ray diffraction (XRD) peaks and the energy dispersive X-ray spectroscopy (EDX) results, it was determined that the exact chemical stoichiometry for the inter-layer was that of $Fe_2Al_5$. In some samples, an X-layer was formed between the Al and the inter-layer of $Fe_2Al_5$ at high annealing temperature of around $550^{\circ}C$. The existence of an X-layer enhanced the growth of the inter-layer, which resulted in the delamination of the Al/mild-steel clad materials. Hardness tests were also performed to examine the influence of the annealing temperature on the cold deformability, which is a very important property for the deep drawing process of clad materials. The hardness value of mild steel gradually decreased with increasing annealing temperature. Especially, the value of hardness sharply decreased in the temperature range between $525^{\circ}C$ and $550^{\circ}C$. From these results, we can conclude that the optimum annealing temperature is around $550^{\circ}C$ under condition of there being no X-layer creation.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.401-412
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• 1998

The aim of this study was to measure the regional micro-shear bond strength of dentin bonding agents to dentin, and to investigate the relationship between the micro-shear bond strength and two dentinal characteristics ; Vickers hardness and remaining dentin thickness. Twenty-four freshly extracted, noncarious human molars were selected for this study. The materials tested in this study consisted of two commercially available dentin bonding agents (MAC-BOND, ONE-STEP) and two restorative light-cured composite resins (AELITEFIL, Z100). The occlusal or side surface of tooth crown was sectioned to expose dentin, and the exposed surface was finally polished with # 600 sandpaper. Four groups of application methods were used combining the filling materials and the dentin bonding agents. The composite resin-attached tooth specimens were embeded in a cold cure acrylic resin, and were cut with a low speed diamond saw to the dimension of 1mm $\times$ 1mm. Nine specimens were obtained from each tooth. The cut specimens were divided into three groups depending on the position of the dentin bonding surface. The micro-shear bond strength, remaining dentin thickness, and dentinal hardness were measured. Experimental results were then statistically analyzed with ANOVA. t-test, Scheffe test, and regression analysis. From this experiment, the following results were obtained : 1. In the case of occlusal surface bonding, the pooled micro-shear bond strength of ONST-AELIT group (16.62 MPa) was significantly higher than that of MACB-AELIT group (9.91 MPa) (p<0.05). However, there was no significant difference in the micro-shear bond strength depending on the dentin position (p>0.05). 2. In the case of side surface bonding of crown, the pooled micro-shear bond strength of four different bonding groups was not significantly different among each other (p>0.05). However, in three of the test groups (ONST-AELIT, MACB-Z100, ONST-Z100), the micro-shear bond strength to the lower 1/3(III) position was significantly lower than that to middle 1/3(II) position of surface (p<0.05). 3. In the ONST-AELIT bonding group, the pooled micro-shear bond strength to the occlusal surface was significantly lower than that to the side surface of crown (p<0.05). 4. There was no significant correlation between the micro-shear bond strength and dentin hardness / remaining dentin thickness (p>0.05).

• 한국수산과학회지
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• 제54권2호
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• pp.145-151
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• 2021

When manufacturing Alaska pollack Gadus chalcogrammus surimi for 3D printing, it examined the characteristics of physical properties and sensuality by adding polysaccharides alginic acid [0, 1, 2, 3% (w/w)]. As a result of the color value of surimi by adding alginic acid, it showed that the lightness of heated surimi containing 2% (w/w) alginic acid was the highest and ∆E value was the lowest. In the changes in physical properties, the heated surimi of 3% (w/w) alginic acid content showed the lowest values of hardness, springiness, cohesiveness, gumminess, chewiness and resilience, but the highest adhesiveness. In the case of fried surimi, its hardness, cohesiveness, gumminess, chewiness and resilience were the lowest at the content of 3% (w/w) alginic acid. After 7 days of cold storage, the hardness, gumminess, and chewiness of heated surimi with an alginic acid content of 2% (w/w) were significantly higher, and fried surimi was also the same. In the results of the sensory evaluation, there were significant differences according to the alginic acid content in hardness and fishy smell, and as the alginic acid content increased, it felt more fishy smell, resulting in poor preference.

• 한국수산과학회지
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• 제55권5호
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• pp.655-661
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• 2022

Iota carrageenan-containing surimi was refrigerated for 7 days to investigate the change in its properties. Physical properties, color differences, and sensory evaluation were tested for analysis after addition of 0-3 Wt% iota carrageenan. In unheated surimi, the 2% carrageenan- containing surimi had higher chromaticity and color difference compared to the surimi without added carrageenan. However, the surimi with 3% iota carrageenan showed enhanced yellowness, resulting in a modified color difference. Surimi containing iota carrageenan showed the same trend in color difference in heated surimi after storage for 7 days, particularly when carrageenan content was 2% or greater. The hardness, gumminess, and chewiness of the heated Iota carrageenan-containing surimi also increased after 7 days of storage. Compared to surimi without added carrageenan, the heated Iota carrageenan-containing surimi had higher hardness, gumminess, chewiness, and lower adhesiveness after storage. The overall preference for surimi decreased, while the hardness increased, when carrageenan was added. Therefore, the addition of the iota carrageenan to stored surimi can significantly enhance its hardness.

• Journal of Animal Science and Technology
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• 제49권3호
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• pp.387-394
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• 2007

돼지 뒷다리 부위의 발골시간이 프레스햄의 품질에 미치는 영향을 알아보고자, 본 실험을 실시하였다. 그 결과, 원료육의 pH는 두 근육 모두 온도체 발골육이 유의적으로(p<0.05) 높았으며, 온도체 발골육 중 SM이 BF 보다 유의적으로(p<0.05) 높은 pH값을 보였다. 표면 육색의 경우 온도체 발골육의 명도(L*) 값이 냉도체 발골육보다 유의적으로(p<0.05) 낮게 나타났으며, 온도체 발골육 중 SM이 BF 보다 유의적으로(p<0.05) 낮은 명도 값을 나타내었다. 또한 온도체 발골육의 근절길이는 냉도체 발골육보다 긴 것으로 나타났다(p<0.05). 제품의 색 및 pH는 유의적인 차이를 보이지 않았지만, 온도체 발골육으로 제조한 프레스햄의 경도에서 냉도체보다 유의적으로(p<0.05) 낮게 나타났다. 또한 전체적인 기호도에서 발골시간에 따른 차이보다는 온도체 발골 및 냉도체 발골육의 SM근육을 이용하여 제조된 프레스햄이 BF 근육보다 높은 기호도를 나타내었다.

• 한국식품과학회지
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• 제11권2호
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• pp.131-137
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• 1979

수삼(水蔘)을 CA저장(貯藏)하여 그 저장효과(貯藏?果)를 검토하고 또 저장(貯藏)한 수삼(水蔘)으로 가공(加工)한 홍삼(紅蔘)의 품질(品質)을 평가(評價)한 결과(結果)는 다음과 같다. 1. 수삼(水蔘)을 보통 냉장(冷藏)하니 저장(貯藏) 100일(日) 부터 곰팡이가 발생하였으나 CA저장(貯藏)의 경우는 6개월(個月) 후(後)에 도 외관(外觀)에 이상(異狀)이 없었다. 2. 수삼(水蔘)의 중량감(重量減)은 저장(貯藏) 180일(日)에서 냉장구(冷藏區)가 9%, CA구(區)가 $4{\sim}5%$이었다. 또 경도(硬度)는 CA구(區)가 냉장구(冷藏區)보다 높았다. 3. 수삼(水蔘)은 저장(貯藏)에 따라 고미(苦味)가 감소(減少)하였고, 냉장구(冷藏區)는 CA구(區)보다 감소(減少)가 컸다. 4. 수삼(水蓼)의 호흡량(呼吸量)은 전(全) 저장기간(貯藏期間)을 통하여 CA구(區)는 냉장구(冷藏區)보다 낮았다. 5. 저장(貯藏) 180일(日)의 수삼(水蓼)으로 가공(加工)한 홍삼(紅蓼)은 gel화(化)가 불완전(不完全)하고, 껍질이 유리(遊離)되었을 뿐만 아니라 total saponin함량(含量)이 크게 감소(減少)하였다.

• 한국잠사곤충학회지
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• 제38권2호
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• pp.93-99
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• 1996

고조삽목후 삽수의 동아가 발아할 때 0.1~0.4% Colchicine 수용액을 4~5일간 적하하여 용천뽕의 동질4배체 2계통, 영변뽕의 동질4배체 1계통을 육성하였으며 주요 재배학적 특성은 다음과 같다. 1. 봄철의 탈포기는 모품종보다 2일간 늦으나 발아후의 발육속도가 빨라서 5개엽기는 모품종과 동일한 중생뽕이었다. 2. 잎모양은 폭광형이고 잎자루는 길고 굵으며 잎두께는 모품종보다 17~33% 두껍고 1엽중은 무겁고 잎면적중은 21~31% 증가하고 엽록소함량은 11~33% 증가하여 우수한 엽질적 요소를 갖추었다. 3. 모품종보다 가지길이는 짧고 가지수도 적으며 마디사이길이는 같거나 약간 길어지며 굵어져서 가지의 구성요소는 다소 불량하였디. 4. 가지끝마름길이 비율로 나타낸 내동성은 4원뽕 23호, 24호는 용천뽕과 비슷하고 4원뽕25호는 영변뽕보다 강하였고 뽕나무 오갈병 발생율은 높았다. 5. 모품종보다 수량성은 낮고 신초엽량비율과 정엽량비율은 약간 높았다. 6. 4원뽕23호와 24호는 염성이 비교적 높아서 62%의 교잡성공율을 나타내었으나 4원뽕25호는 염성이 낮고 교잡성공률은 23.9%이었다.