• 한국축산식품학회지
• /
• 제27권2호
• /
• pp.171-178
• /
• 2007

본 연구는 숙성온도와 숙성기간이 한우 거세우 배최장근의 육질 특성에 미치는 영향을 구명하고자 숙성온도를 0, $4^{\circ}C$로 하여 2, 7, 14, 21, 28, 49일 동안 숙성하면서 한우 거세우 배최장근의 pH, 전단력, MFI, 가열 및 육즙감량, 전자현미경 관찰, 관능검사 및 아미노산 조성을 분석하였다. pH는 숙성온도가 $0^{\circ}C$일 때 숙성 21일까지, 숙성온도가 $4^{\circ}C$일 때 숙성 14일까지 증가하다가 감소하였다(p<0.05). 전단력 값은 숙성 14일부터 28일까지 $4^{\circ}C$에서 숙성한 배최장근이 $4^{\circ}C$보다 유의적으로 낮았고, 숙성기간이 경과함에 따라 유의적으로 연도가 향상되었다(p<0.05). MFI의 경우 $4^{\circ}C$에서 숙성한 배최장근 보다 $0^{\circ}C$에서 높은 경향을 보였고, 숙성기간이 경과함에 따라 유의적으로 증가하였다(p<0.05). $0^{\circ}C$에서 숙성한 배최장근의 가열 및 육즙감량이 $4^{\circ}C$보다 적은 경향이었고, 숙성기간이 경과함에 따라 유의적으로 증가하였다(p<0.05). 관능검사에서 연도와 다즙성은 $0^{\circ}C$에서 숙성한 배최장근이 $4^{\circ}C$ 보다 좋은 평가를 보였고, 숙성기간이 경과하면서 유의적으로 높은 평가를 얻었다(p<0.05). 전자현미경에 의한 미세구조 변화는 $4^{\circ}C$에서 숙성한 배최장근이 $0^{\circ}C$보다 1주일 빠르게 Z-disk의 붕괴가 확실하게 관찰되었고, 숙성기간이 경과하면서 Z-disk의 붕괴정도가 많아졌다. 아미노산 함량 변화는 $4^{\circ}C$에서 숙성한 배최장근이 $0^{\circ}C$보다 높은 경향이었고, 숙성기간이 경과하면서 각 아미노산 조성의 함량이 유의적으로 증가하였다(p<0.05). 이상의 결과를 종합하면, 한우 거세우 등심의 최적 숙성 조건은 $0^{\circ}C$에서는 14일간, $4^{\circ}C$에서는 7일간 숙성하는 것이 바람직한 것으로 사료되며, 향후 숙성기술의 산업적 적용을 위하여 한우의 부위 및 근육별 적정 숙성기간 설정 연구가 필요할 것으로 생각된다.

• 약학회지
• /
• 제6권2호
• /
• pp.13-17
• /
• 1962

The effects of glycerin and sorbitol and ageing of antacid activity of aluminum hydroxide gel has been described. The results under accelerated temperatures showed sorbitol had excellent stabilizing effect and glycerin had promoting effect by contraries.

• 열처리공학회지
• /
• 제33권4호
• /
• pp.161-172
• /
• 2020

The tensile property of A5082 and A6060 aluminium wrought alloys was investigated, in terms of the strain rate sensitivity on alloy conditions by heat treatment and bake hardenability on pre-strain prior to strain ageing. The tensile test was carried out in a range of strain rate of 4.17 × 10^-5 s^-1 ~ 4.17 × 10^-5 s^-1 in room temperature and the nominal range of pre-strain was 3.0 ~ 10.5%. The tensile deformation of A5082 alloys is characterized as typical case of dynamic strain ageing with negative strain rate sensitivity for all conditions, and the tensile strength indicates a similar level regardless of alloy conditions, except only in full annealed condition. The stress-relief annealing on A6060 alloys can induce practical decrease in strength level of over approximately 100 MPa without any ductility loss, compared to as-rolled condition, while a full annealed and aged condition leads remarkable strengthening effect with the decrease of tensile elongation. Additionally, the bake hardenability of A5082 alloy by strain ageing indicates a negative dependence upon the increase of pre-strain, while A6060 alloy exhibits a positive sign even in low level relatively compared with conventional SPCC.

• 한국안전학회지
• /
• 제19권4호
• /
• pp.1-7
• /
• 2004

This study investigated the effects of aging on the transformation behavior of $Ti-50.1at\%$ Ni alloy by means of differential scanning calorimetry. It was found that aging in the temperature range of $350^{\circ}C\~550^{\circ}C$ induced complex transformation behavior, involving the R-phase and multiple-stage martensitic transformation. Usually aged Ni-rich NiTi alloys undergo martensitic transformation on cooling from high temperatures in two step : B2 to R and then R to Bl9'(normal behavior). But under certain ageing conditions, the transformation can also occur in three or more step(unusual multiple step behavior). In the present study we use differential seaming calorimetry(DSC) for a systematic investigation of the evolution of transformation behavior with ageing temperature and time.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.148-153
• /
• 2017

HTPB 추진제는 자연 저장 기간 동안 내부 시효성 물질들에 의한 물리 화학적 반응으로 인해 서서히 노화가 진행된다. 각기 다른 시간-온도 조건에서 이들 시효성 물질의 가속 노화 시험을 통해 자연 상태에서의 노화 특성을 모사할 수 있다. 본 논문에서는 장기 저장 기간 동안 느리게 진행되는 HTPB 추진제의 물리 화학적 반응에 의한 노화 특성을 HFC(Micro-Heat Flow Calorimeter)로 분석 평가하여 수행한 HTPB 추진제의 신개념 수명 예측 기술에 대하여 고찰하였다.

• 한국안전학회지
• /
• 제20권3호
• /
• pp.27-33
• /
• 2005

The shape memory effect in Ti-50.4at.%Ni alloy after solution treatment at 1273K for 2h and aged at 350, 450, $550^{\circ}C$ for 0.5, 1, 1.5, 2, 4, 10hrs had been investigated by differential scanning calorimetry measurement. It was found that ageing in the temperature range of $350^{\circ}C{\sim}550^{\cric}C$ induced complex transformation behavior, involving the R-phase and multiple-stage martensitic transformation. Usually aged Ni-rich NiTi alloys undergo martensitic transformation on cooling from high temperatures in two step : Austenite to R-phase and then R-phase to Martensite (normal behavior). In sample aged at $350^{\circ}C$ two distinct DSC peaks arised giving evidence of intermediate stages of martensite transformation. This results in the nucleation and growth of coherent $Ni_4Ti_3$-precipitate. These explain all features of the evolution of DSC charts during ageing including the number of distinct DS peaks and their positions.

• 한국의류학회지
• /
• 제20권6호
• /
• pp.962-974
• /
• 1996

This study aimed to provide basic data in designing clothes for the elderly women. The subjects in this study were 230 elderly women over sixty years old. The major objectives of this study were as follow; 1 Categorization of the subjects based on their age and Rohrer index. 2. Relationship between age and body cathexis. 3. Relationship between age and clothing size satisfaction. 4. Relationship between age and clothing attitudes. The results were as follows; 1. Height decreased while bust, waist and hip circumstances increased with ageing. 2. All subjects were dissatisfied with their body changes associated with ageing. 3. The women over seventy years old were more dissatisfied with apparel size than those in the sixties. Especially the women aged over 75 complained the back length and the crotch length. 4. The elderly wowed were insterested in sewing condition, size and comfort with ageing even though they considered color and design as the most important attribute in selections clothes.

• 한국고분자학회:학술대회논문집
• /
• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
• /
• pp.363-363
• /
• 2006

Bonding of composite materials with an adhesive layer is one of the most promising alternatives to classical bonding techniques. The use of several surface treatments may greatly increase this adhesion behavior at the initial state. Then in order to see the influence of the thickness of polymer matrix on the adhesion of composite assembly, different surface treatment, which can reduce or increase this thickness, are used (peel ply, tear ply, excimer laser). The influence of this specific parameter is not only discussed at the initial state but also after thermal ageing of the whole bonded assembly. Results show that the best performances at the initial state are not obviously the best performances after ageing.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 추계학술대회 논문집
• /
• pp.47-51
• /
• 2007

The present paper reports the life time prediction of Acrylonitrile-Butadiene rubber (NBR) fuel cell gasket materials as a function of operational variables like acid concentration, ageing time and temperature. Both material and accelerated acid-heat aging tests were carried out to predict the useful life of the NBR rubber gasket for use as a fuel cell stack. The acid ageing of the gasket compounds has been investigated at 120, 140 and $160^{\circ}C$, with aging times from 3 to 600 h and increasing acid ($H_2SO_4$) concentrations of 5, 6, 7 and 10 vol%. Material characteristics the gas compound such as cross-link density, tensile strength and elongation at break were studied. The hardness of the NBR rubber was found to decrease with decreasing acid concentration at both 120 and $140^{\circ}C$, but at $160^{\circ}C$ interestingly the hardness of the NBR rubber increased abruptly in a very short time at different acid concentrations. The tensile strength and elongation at break were found to decrease with increase in both the acid concentrate ion & temperature. The life time of the compounds were evaluated using the Arrhenius equation.

• 한국축산식품학회지
• /
• 제32권3호
• /
• pp.369-375
• /
• 2012

The current study was carried out to investigate the impact of extraction conditions on the free amino acid level and type in beef longissimus muscle. The sample blocks were chiller aged for 1 d and 7 d at $4^{\circ}C$. There are three homogenization speeds (11,000, 19,000 and 24,000 rpm) for bigger and two speeds (11,000 and 13,000 rpm) for smaller homogenizer's dispersing tools were used for evaluation. Results showed that chiller ageing greatly (p<0.05) increased extractable free amino acids, except cystine. Homogenization with the bigger dispersing tool at 24,000 rpm resulted in the highest free amino acid levels for both 1 and 7 d samples. Significant differences (p<0.05) in the mean values of most amino acids due to the effect of speed and interactions between ageing times. However, the speed effect and interaction between ageing with homogenization speed were not significant (p>0.05) for most of the amino acids except valine and isoleucine when using the smaller dispensing tools. The current data indicated that a standardized method for free amino acid types and levels of aged beef samples. In addition, the results also suggested that utilization of a big dispensing tool at high homogenization speed is a better condition for releasing free amino acid contents in beef samples.