• Animal Bioscience
• /
• 제34권11호
• /
• pp.1849-1858
• /
• 2021

Objective: Tenderness is a very complex feature, and the process of its formation is very complicated and not fully understood. Its diversification is one of the most important problems of beef production, as a result beef aging is widely used to improve tenderness as it is believed to provide a homogeneous product to consumers. While few studies have evaluated the muscle structure properties in relation to tenderness from early post-mortem, there little to no information available on how the muscle nanostructure of beef carcasses changes during post-mortem ageing to determine the appropriate aging time for acceptable tenderness. Methods: Muscle nanostructure (myofibril diameter [MYD], myofibril spacing [MYS], muscle fibre diameter [MFD], muscle fibre spacing [MFS], and sarcomere length [SL]), meat tenderness and cooking loss [CL]) were measured on 20 A2 longissimus muscles of Bonsmara, Beefmaster, Hereford, and Simbra at 45_mins, 1, 3, and 7 days post-slaughter. Muscle nanostructure was measured using a scanning electron microscope, while tenderness was measured using Warner Bratzler shear force. Results: At 45 minutes post-slaughter, breed affected MYD and MYS only, while at 24_hrs it also affected MFD and MFS. On day 3 breed effected MFS and SL, while on day 7 breed effected tenderness only. As the muscles matured, both MYD and MYS decreased while CL increased, and the muscles became tender. There was no uniformity on muscle texture features (surface structure, fibre separation, muscle contraction, and relaxation) throughout the ageing period. Conclusion: Meat tenderness can be directly linked to breed related myofibril structure changes during aging in particular the MYD, spacing between myofibrils and their interaction; while the MFD, spacing between muscle fibres, SL, and CL explain the non-uniformity in beef tenderness.

• 한국가족복지학
• /
• 제53호
• /
• pp.161-198
• /
• 2016

본 연구는 과거 성인자녀에 대한 모(母)의 경제적, 시간적 지원(손자녀 돌봄)이 이후 모와 성인자녀 간의 동거에 어떠한 영향을 미치는지 살펴보는 것을 연구의 목적으로 하였다. 연구 수행을 위해 모와 성인자녀 간의 위계적 관계 구조를 고려하여 다수준 로지스틱 분석 방법을 사용하였고, 고령화연구패널조사(Korean Longitudinal Study of Ageing: KLoSA)의 1 차부터 4차 연도까지의 자료를 이용하여 1,925명의 모와 7,460명의 성인자녀를 분석 대상으로 삼았다. 본 연구의 분석 결과를 간략히 제시하자면 다음과 같다. 먼저, 과거 모(母)가 성인자녀에게 제공한 경제적 지원은 이후 모와 성인자녀 간의 동거에 통계적으로 유의미한 영향을 미치지 못하는 것으로 나타났다. 그러나 손자녀 돌봄 시간을 통해 측정하였던 시간적 지원은 그것의 양이 많을수록 이후 세대 간 동거의 가능성이 증가하는 것으로 나타났다. 이는 노모와 성인자녀 간에 세대 간 지원을 통한 장기적 호혜 관계가 성립될 수 있으며, 그러한 관계 형성에서 손자녀 돌봄이 중요한 위치를 차지할 수 있음을 암시한다. 본 연구는 이와 같은 결과를 기초로 이론적 및 실천적, 정책적 함의를 제시하였다.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
• /
• pp.271-277
• /
• 2011

Hanji(Korean traditional paper) is made from bark of paper mulberry(Broussonetia kazinoki). For a long time, Hanji has been used in various fields, such as paintings, printing paper, as specialty paper. The utilization of Hanji will become more and more diverse. One of the characteristic properties of Hanji is a long life time comparing to western paper. The mucilage which must be used in Hanji manufacturing should effect the conservation properties of Hanji. The effectiveness of the mucilage in aging of Hanji was evaluated in this paper. Strength properties of thermal aged Hanji made with synthetic mucilage decreased more slowly than those of Hanji made with natural mucilage. As prolonged aging time, all Hanji made mucilage increased oxidation index. But, Hanji made with PAM was most stable in oxidation of cellulose.

• 열처리공학회지
• /
• 제18권3호
• /
• pp.172-176
• /
• 2005

Modern automobiles are built with a steadily increasing variety of materials and semifinished products. The traditional composition of steel sheet and cast iron is being replaced with other materials such as aluminum and magnesium. But low formability of these materials has prevented the application of the automotive components. The formability can be enhanced by conducting the warm hydroforming using induction heating device which can raise the temperature of the specimen very quickly. The specimen applied to the test is A6061, A7075 extruded tubes which belong to the age-hardenable aluminum alloys. But in the case of A6061 age hardening occurs at room temperature or at elevated temperatures before and after the forming process. In this study the effects of the heating condition such as heating time, preset temperature, holding time during die closing and forming time on the hydroformability are analyzed to evaluate the phenomena such as dynamic strain hardening and ageing hardening at high temperatures after the hydroforming process.

• 가정과삶의질연구
• /
• 제27권3호
• /
• pp.31-43
• /
• 2009

Using the first wave of KLoSA(Korean Longitudinal Study of Ageing) beta version, this study analyzed factors affecting early retired men's subjective life satisfaction through Binary Logit and Multiple Regression. Total 552 men were selected as a sample. The main results of empirical analysis in this study were as follows: The retirement reason(health-) and monthly household income(+) affected whether they were satisfied with the retirement life or not and subjective life satisfaction over all. Especially, the retirement reason(health-) had a stronger effect on whether early retired min were satisfied with the retirement life or not and their subjective life satisfaction than monthly household income revealed significant variable in previous studies. This result represents that the retiree's life satisfaction analysis model must include retiree's characteristics at the time of retirement as well as retiree's current status characteristics or socio-economic characteristics.

• 한국정밀공학회지
• /
• 제17권6호
• /
• pp.89-95
• /
• 2000

The engine idle speed mode becomes worse as one drives a vehicle for several years. This is due to ageing of engine and power-train parts. In this case, unstable idle conditions such as engine stall and droop are frequently experienced when the engine gets heavy torque loads due to power steering pump and air conditioning compressor. The objective of this paper is to study on the idle speed control using PID controller under load disturbances. The input of the PID controller is an error of rpm. The output of the PID controller is an ISCV duty cycle. The dSPACE Controller Boards are used to interface with engine. The on-vehicle test is realized using by SIMULINK and BLOCKSETS tools. The real time interface control panel supplied by Control Desk S/W is designed to have good results in engine idle speed control.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 E
• /
• pp.2405-2407
• /
• 1999

In recent, the application of polymeric insulators for outdoor is significantly increasing. These materials have shown good performance in service, but had disadvantages under long-term exposure to contamination and moisture, resulting in some problems. Thus, this study concentrated on the development of technique evaluating the insulating status. Experiment was referred to lEC publ. 587, with data aquisition system to monitor leakage current. The components of leakage current investigated were waveform and 3rd harmonic. FFT was conducted for the analysis of harmonic components. The distortion of waveform with application time of voltage was evident, and so the 3rd harmonic component.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2005년도 춘계학술대회논문집
• /
• pp.209-213
• /
• 2005

To enhance the reliability of distribution transformers in service and to reduce the cost of maintaining and replaceing these, the condition and life of those insulating system should be evaluated accurately and the time to replace should be determined economically. Since the transformer failures related to insulation failure indicates that the primary cause is normally mechanical failure of integrity due to loss of mechanical strength as a result of degradation, the tensile strength characteristics of paper during ageing under accelerated conditions in insulating oil and research trends for assessing the life of insulating paper were investigated.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제5권3호
• /
• pp.373-379
• /
• 2005

In many cases, it is more practical and economical to repair a system than to replace the whole system or to perform a complete overhaul when the system fails. Two basic replacement policies were proposed by Barlow and Hunter(1960) and Morimura (1970), in which the minimal repair times are identically distributed. But, as Lam(1988) pointed out, in many cases of deteriorating system, in view of ageing and cumulative wear, the repair time will tend to be longer and longer. In this note, the two basic replacement policies are considered for a repairable system with linearly increasing repair times. Optimal policies, which maximize the steady state availability of the system, are obtained for the Weibull failure rate case.

• 한국세라믹학회지
• /
• 제30권7호
• /
• pp.563-570
• /
• 1993

Spherical, monosized gadolinium compound was prepared by the reaction of Gd(NO3)3 solution with decomposition products of urea in the solution at evaluated temperature. Chemical composition and calcination characteristics of spherical gadolinium compound prepared were investigated by X-ray IR and TG-DTA. The approximate chemical composition of the spherical particle precipitated was Gd(OH)CO3.1.5H2O. Gd(OH)CO3.1.5H2O was calcined to monoclinic type Gd2O3 at 115$0^{\circ}C$ via cubic type Gd2O3 near $600^{\circ}C$. The effects of various parameters such as pH, temperature, concentration ratio of urea to gadolinium precusor, ageing time, and others material (CCl3COOH and HOCNH2) in stead of urea as precipitating agent on the properties of the resulting precipitates were studied systematically.