• 열처리공학회지
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• 제10권4호
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• pp.237-245
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• 1997

A study was conducted to examine the effects of In addition on the precipitation behaviors of Al-2.1Li-2.9Cu alloy by differential scanning calorimetry, transmission electron microscopy and micro-hardness tester. DSC analysis was measured over the temperature range of $25{\sim}550^{\circ}C$ at a heating rate of $2{\sim}20^{\circ}C$/min. The heat evolution peaks due to the formation of GP zone and ${\delta}$'phase shift to higher temperature and the peaks to $T_1$ and ${\theta}$'phases shift to lower temperature by In addition. From this result, it was proved that the formation of GP zone and ${\delta}$'phase is suppresed whereas that of $T_1$ and ${\theta}$'phases are accelerated by the In addition of 0.15wt%. The age hardening curve aged at $190^{\circ}C$ showed that the In bearing alloy(alloy B) has more faster age hardening response and a higher peak hardness than In-free alloy(alloy A), attributed to the fine and homogeneous distribution of $T_1$ and ${\theta}$'phases. The activation energies for the formation of ${\delta}$'phase in In-free and In-bearing alloys are 22.3kcal/mol and 18.6kcal/mol, respectively. Those for $T_1(+{\theta}^{\prime})$ phase of In-free and In-bearing alloys are 24.3 and 37.5kcal/mol, respectively. Quenched-in excess vacancies play an important role to the formation of precipitates.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.235-249
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• 1995

This study was designed to identify the lymphocytes present and to examine the relation between lymphocytes population and clinical symptoms of the pulps clinically diagnosed as normal and irreversible pulpitis. We recorded the history and severity of the pain and performed several clinical tests, before extirpation of vital, irreversibly inflamed pulps in routine endodontic treatment. Then the teeth were divided into two groups. Five teeth, categorized in acute symptom group, had severe spontaneous pain, particularly at night and were extremely sensitive to cold and heat. The other 15 teeth with history of mild to moderate pain and with or without cold or heat responses were categorized as chronic symptom group. Inflamed pulps were also classified into 8 minor groups by presence or absence of signs or symptoms related to the involved teeth, including the presence of pain on percussion, pain on heat and cold stimuli and the periodontal pocket depth. All extirpated pulps were immediately immersed in ultra low-temperature freezer($-74^{\circ}C$), and they were sectioned $6{\mu}m$ in thickness. Specimens were stained using three-stage indirect immunoperoxidase techniques(DAKO, LSAB kit) and monoclonal antibodies for detecting the presence of T lymphocytes(T), B lymphocytes(B) and helper(T4) and suppressor(T8) lymphocytes. Following results were obtained; 1. All the examined normal and inflamed pull) tissues had positive staining for T lymphocytes and T helper and T suppressor cells. But B cells were observed only in inflamed pulp. 2. Statistically more T and B cells were observed in acute symptom group as compared with chronic symptom group(p<0.05). 3. Cell ratio of BIT in acute symptom group were significantly higher than that of chronic symptom group(p<0.05). 4. Only B cells were significantly increased in the percussion positive group than the number of B cells in percussion negative group(p<0.05). 5. No differences were observed in the number of different cell types among other minor groups.

• 한국식품과학회지
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• 제2권2호
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• pp.8-16
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• 1970

69종(種)의 각종 식물체(植物體)를 대상으로 하여 이것을 마쇄(磨碎)한 slurry로부터 총질소(總窒素)의 추출상황(抽？狀況)을 조사(調査)하고, 추출액(抽出液)으로 부터의 LPC의 제조방법(製造方法)을 검토(？討)하여 다음과 같은 결과(結果)를 얻었다. 1. 원료(原料)의 총질소(總窒素)의 함량(含量)이 클수록 총질소(總窒素)의 추출비(抽出比)는 커지며, 원료(原料)로부터의 추출(抽出)은 적어도 2회추출(回抽出)까지 필요(必要)하다. 원료엽체(原料葉體)로부터의 1차(次) 추출액(抽出液) $(E_1;\;%)$, 2次 抽出液$(E_2;\;%)$와 (T; %)사이에는 $E_1=0.8168T,\;E_2=0.1830T$의 1차(次) 관계식(關係式)이 성립(成立)한다. 2. pH 처리(處理)에 의한 LPC 생성(生成)에 있어서 pH 3 이하(以下)에서는 생성(生成)된 LPC의 색택(色擇)이 갈변(褐變)되고 제품(製品)의 탄력성(彈力性)이 커지며, 그 정도는 pH가 낮아질 수록 현저(顯著)해진다. pH 처리(處理)에 의한 LPC 생성(生成)의 지적(至適) pH 는 $3.5{\sim}4.5$ 라고 할 수 있다. 3 추출액(抽出液)으로 부터의 LPC의 생성(生成)은 TCA 처리(處理)> pH 4> pH 3> 열처리(熱處理)의 순서(順序)가 되며, TCA 처리(處理)에 비(比)하여 pH 4 처리(處理)는 10%감(減), pH 3 처리(處理)는 11.4%감(減), 열처리(熱處理)는 14.8%감(減)이었다. 4. pH 처리법(處理法)은 열처리법(熱處理法) 보다 LPC의 생성량(生成量)이 다소 높으나 대량처리시(大量處理時)의 pH 조절(調節)의 복잡성(複雜性)과 생성제품(生成製品)의 품질(品質)로 보아 열처리(熱處理)에 의한 LPC의 생성방법(生成方法)이 효과적(效果的)이고 간편(簡便)하다.

• 열처리공학회지
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• 제18권5호
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• pp.288-296
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• 2005

The corrosion behaviors of Zr-based alloys were very sensitive to their microstructures which were determined by manufacturing process. The specimens of Zr-based alloy named as HANA-4 for nuclear fuel cladding were investigated in order to get the optimized manufacturing process such as the intermediate annealing temperature and cold working steps after the ${\beta}$ quenching. From the microstructural analysis, cold worked microstructure of the samples was changed to the recrystallized microstructure by performed process. The corrosion behaviors of HANA-4 alloy were affected by the different manufacturing process. The ${\beta}$-Zr phase was formed in the matrix and the Nb concentration in the ${\beta}$-Zr phase was increased as progressing the manufacturing process. So, it was found that the corrosion rate of HANA-4 alloy was affected by the Nb concentration in the matrix.

• 한국초전도ㆍ저온공학회논문지
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• 제16권2호
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• pp.24-28
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• 2014

Magnesium diboride superconductor is still of considerable interest because of its appealing characteristics towards application mainly at around 20 K. Unlike Nb-based superconductors, $MgB_2$ can be operated by cryogen-free cooler which provides a cost effective alternative at low field of around 2-5 T. To explore this operating field region considerable efforts are necessary to marginally improve the superconducting properties of $MgB_2$. Under this situation, even the heat treatment environment during the synthesis is considered as an important factor. The addition of $H_2$ gas in small amount with Ar as a mixed gas during annealing has an adverse effect on the superconducting properties of $MgB_2$. It is although interesting to find that the presence of Mg vapor along with hydrogen during heat treatment results in the appreciable improvement in the flux pinning and the overall response of the critical current density for the ex-situ $MgB_2$ samples.

• 환경위생공학
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• 제5권2호
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• pp.103-110
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• 1990

For production of thermophilic and alkaline protease, Bacillus sp. strain AP-5 was isolated from a compost. The production of the protease was reached at maximum for 4 days at $55^{\circ}$ in standing culture. Chitin and Cellulose as carbon source, and Skim Milk as nitrogen source were favorable for the production of the enzyme. Optimal temperature and optimal pH of the enzyme was $55^{\circ}$ and 11, respectively. Metal ion didn't effect on the enzyme activity, the protease was very stable at heat treatment of 30 min at $55^{\circ}$.

• 한국동물생명공학회지
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• 제34권3호
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• pp.173-182
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• 2019

This study was performed to evaluate the effect of heat stress on the status of physiological responses, blood parameter, serum T3 and cortisol, and heat shock proteins (HSP 27, 70, and 90) of Hanwoo cattle. Six Hanwoo steers (242.8 ± 7.2 kg of BW) were housed in the climate-controlled respiration chambers. The experiment consisted of 7 days (control; 0 day) at thermoneutral (air temperature (Ta) of 15℃ and relative humidity (RH) of 60%; temperature-humidity index (THI) = 64), and by 3 and 6 days (treatment groups) at heat stress (Ta of 35℃ and RH of 60%; THI = 87). Body temperature of each parts (frank, rump, perineum and foot) and rectal temperature elevated in heat stress groups (3 days and 6 days) than the control group (0 day). Respiration rates increased in 3 days and 6 days (88.5 ± 0.96 bpm and 86.3 ± 0.63 bpm, respectively) from 0 days (39.5 ± 0.65 bpm). Feed intake significantly decreased in heat stress groups (3 days and 6 days, 3.7 ± 0.14 kg and 4.0 ± 0.15 kg, respectively) than the control group (0 day, 5.0 ± 0.00 kg). In addition, final BW significantly decreased in heat stress groups (3 days and 6 days, 211.8 ± 4.75 kg and 215.5 ± 3.50 kg, respectively) than the control group (0 day, 240.0 ± 25.00 kg). However, heat stress has no significant effect on blood parameter, serum T3 and cortisol. Nevertheless, heat stress increased HSPs mRNA expression in liver tissue, and serum concentration of HSPs. Despite Hanwoo cattle may have high adaptive ability to heat stress, our results suggested that heat stress directly effect on body temperature and respiration rate as well as serum and tissue HSPs. Therefore, we are recommended that HSPs could be the most appropriate indicators of Hanwoo cattle response to heat stress.

• 한국식품위생안전성학회지
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• 제26권1호
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• pp.31-35
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• 2011

본 연구에서는 최근 새롭게 출현한 식중독 세균인 Arcobacter butzleri 국내 분리 균주를 고온과 냉장 및 냉동 조건에 노출시킨 후 생존성을 조사하였다. 열처리를 한 경우 $50^{\circ}C$ 5분 이후부터 유의적으로 감소하였으며, $60^{\circ}C$와 $70^{\circ}C$ 열처리 조건에서는 생존성이 급격히 감소하였다. $4^{\circ}C$와 $-70^{\circ}C$ 온도에 저장할 경우 유의적인 생존성 감소가 없었으나, $-20^{\circ}C$ 냉동조건에서는 A. butzleri의 생존성이 유의적으로 감소하였다. 특히 장내용물에서 분리된 A. butzleri는 계육에서 분리된 균주보다 열처리에 저항하는 특정이 있었다. 따라서 고온처리 및 냉동 저장 등은 A. butzleri를 효과적으로 제어할 수 있는 기술개발에 활용할 수 있을 것으로 판단된다.

• 열처리공학회지
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• 제7권1호
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• pp.3-10
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• 1994

The structure and mechanical properties of the extruded specimens were investigated in rapid solidified Al-(1, 3, 5) Cr alloys after mechanical alloying. Finer lamellar microstructure could no longer be resolved in the bars obtained by extrusion of the spherical particles after 200 min. of processing time. The structure of extruded bars are highly depended on the processing time of splats. The isothermal annealing of the extruded bars showed that all the alloys had good thermal stability up to $400^{\circ}C$ and did not show the recrystallization phenomena. Severe working of Al-(1, 3, 5) Cr splats produced a very fine grain size and substructural strengthening (high dislocation density and fine grain size). Effects of mechanical alloying on the thermal stability of the extruded bars Al-(1, 3, 5) Cr alloys decreases, with increasing Cr content. But the ultimate tensile Strength in the extruded bars increases with increasing Cr content.

• 한국식품조리과학회지
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• 제6권3호통권12호
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• pp.25-32
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• 1990

In this study, the cis to trans isomerization of unsaturated fatty acids were investigated about Soybean oil (SBO), Corn germ oil (CGO), Cottonseed oil (CSO), Margarine (MG), Shortening (ST) incubated at $40{\pm}2^{\circ}C$ for 35 days and heated at $185{\pm}2^{\circ}C$ for 24 hours. The contents and kinds of trans fatty acids in each sample were determined by GLC after seperating by HPLC. The results were obtained as follows; 1. When samples were incubated at $40{\pm}2^{\circ}C$ for 35 days, the contents of total trans fatty acids were increased from $0.5{\sim}12.3%$ to $0.8{\sim}20.5%$. The kinds of trans fatty acids found were $t-C_{18:1},\;t,c-C_{18:2},\;t,t-C_{18:2},\;t,c,c-C_{18:3}$ in $SBO,\;t-C_{18:1},\;t,c-C_{18:2}$ in $CGO,\;t-C_{16:1},\;t-C_{18:1},\;t,c-C_{18:2},\;t,t-C_{18:2}$ in CSO. Processed oil such as MG and ST showed more complicated composition of trans fatty acids than SBO, CGO and CSO. $t-C_{18:1},\;t,c-C_{18:2},\;t,t-C_{18:2},\;t,c,t-C_{18:3},\;t-C_{20:1}$ were detected in ST. 2. In the case of heating at $185{\pm}2^{\circ}C$ for 24 hours, the contents of total trans fatty acid were $1.6{\sim}37%$. 2% in all samples. Heating made more remarkable isomerization than incubation $(40{\pm}2^{\circ}C)$. Specially, $c,c,t-C_{18:3}$ in $SBO,\;t,t,t-C_{18:3}$ in $MG,\;t,c,t-C_{18:3},\;t,t,t-C_{18:3}$ in ST were detected. 3. The total contents of trans fatty acids of processed oil were higher than vegetable oils. During incubation, trans fatty acids increased in the order of MG>ST>CGO>SBO>CSO, and during heat treatment, MG>ST>SBO>CGO>CSO.