• Journal of Mechanical Science and Technology
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• 제16권7호
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• pp.889-895
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• 2002

This paper presents the effect of external corrosion, material properties, operation condition and design thickness in pipeline on failure prediction using a failure probability model. The predicted failure assessment for the simulated corrosion defects discovered in corroded pipeline is compared with that determined by ANSI/ASME B31G code and a modified B31G method. The effects of environmental, operational, and random design variables such as defect depth, pipe diameter, defect length, fluid pressure, corrosion rate, material yield stress and pipe thickness on the failure probability are systematically studied using a failure probability model for the corrosion pipeline.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1988년도 학술대회지
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• pp.43-46
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• 1988

홍삼 $S_I$-분획의 투여로 중크롬산에 의한 신장세포독성이 감소되었다. 토끼에 중크롬산을 투여하면 급성신부전이 유발되어 10일이내에 대부분이 죽었다. 반면 홍삼 $S_I$-분획을 투여하면 치사율이 상당히 낮아졌으며, 생리적 증상이 현저히 개선되었다. 홍삼 $S_I$-분획의 투여로 중크롬산에 의하여 생기는 glomerulotubular imbalance가 호전되었으며, 당원생성, 해당속도, 젖산 생성속도가 정상화 되었다. 홍삼 $S_I$-분획의 효과는 비타민 C, EDTA, 휴로세마이드에 비하여 월등하였다.

• Clinical and Experimental Reproductive Medicine
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• 제49권3호
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• pp.168-174
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• 2022

Refractory thin endometrium and recurrent implantation failure are among the most challenging infertility-related factors hindering successful pregnancy. Several adjuvant therapies have been investigated to increase endometrial thickness and the pregnancy rate, but the treatment effect is still minimal, and for many patients, these treatment methods can be quite costly and difficult to approach. Platelet-rich plasma (PRP) is an autologous concentration of platelets in plasma and has recently been elucidated as a better treatment option for these patients. PRP is rich in cytokines and growth factors, which are suggested to exert a regenerative effect at the level of the injured tissue. Another advantage of PRP is that it is easily obtained from the patient's own blood. We aimed to review the recent findings of PRP therapy used for patients with refractory thin endometrium and recurrent implantation failure.

• Journal of Power Electronics
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• 제16권4호
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• pp.1426-1437
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• 2016

In different industrial and mission oriented applications, redundant or standby semiconductor systems can be implemented to improve the reliability of power electronics equipment. The proper structure for implementation can be one of the redundant or standby structures for series or parallel switches. This selection is determined according to the type and failure rate of the fault. In this paper, the reliability and the mean time to failure (MTTF) for each of the series and parallel configurations in two redundant and standby structures of semiconductor switches have been studied based on different failure rates. The Markov model is used for reliability and MTTF equation acquisitions. According to the different values for the reliability of the series and parallel structures during SC and OC faults, a comprehensive comparison between each of the series and parallel structures for different failure rates will be made. According to the type of fault and the structure of the switches, the reliability of the switches in the redundant structure is higher than that in the other structures. Furthermore, the performance of the proposed series and parallel structures of switches during SC and OC faults, results in an improvement in the reliability of the boost dc/dc converter. These studies aid in choosing a configuration to improve the reliability of power electronics equipment depending on the specifications of the implemented devices.

• Korean Journal of Acupuncture
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• 제22권4호
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• pp.117-127
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• 2005

Objective : This study was undertaken to determine if Plantaginis Semen herbal acupuncture(PSA) has a protective effect on glycerol-induced acute renal failure in rats. Methods : Rats were dehydrated for 24hr and then injected with 4 ml/kg of 50% glycerol in each hindlimb muscle. In experiments for PSA effect, rats were received 0.1 ml of PSA extraction in both sides of corresponding $Sh\grave{e}nsh\bar{u}(BL_{23})$ of human body for 3 days after injection of glycerol. The experimental group were divided into the normal group, the control group, the sample 1,2,3 group. Results : Glycerol injection decreased glomerular filtration rate and increased urine volume, serum creatinine, BUN level and fractional excretion of $Na^+,\;K^+\;and\;Cl^-$. These results show that glycerol injection bring about acute renal failure. PSA significantly increased glomerular filtration rate and significantly decreased serum creatinine, BUN level and fractional excretion of $Na^+,\;and\;Cl^-$ as compared with control group. Conclusion : These results suggest that PSA can be used in prevention and treatment for acute renal failure. However, the precise mechanisms of PSA protection remain to be determined.

• International Journal of Reliability and Applications
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• 제11권2호
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• pp.123-138
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• 2010

This paper investigates a mathematical model of a system composed of two non-identical unit parallel system with common-cause failure, critical human error, non-critical human error, preventive maintenance and two type of repair, i.e. cheaper and costlier. This system goes for preventive maintenance at random epochs. We assume that the failure, repair and maintenance times are independent random variables. The failure rates, repair rates and preventive maintenance rate are constant for each unit. The system is analyzed by using the graphical evaluation and review technique (GERT) to obtain various related measures and we study the effect of the preventive maintenance preventive maintenance on the system performance. Certain important results have been derived as special cases. The plots for the mean time to system failure and the steady-state availability A(${\infty}$) of the system are drawn for different parametric values.

• 유통과학연구
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• 제3권1호
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• pp.23-42
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• 2005

The service offer expectation and the desire of customers to a large-sized rate influence store also increase as a result of such environmental change. the counter where research of a book was upgraded from differentiation pursuit by competition between business condition in business condition in the case of the domestic rate influence store which has put the focus on service strengthening The work shrine which cannot reach here the competition predominance in the domestic market it will be hard coming to secure, when environmental change of inside large-sized rate influence store industry is taken into consideration The research which tried to receive customer service failure recovery carried out actual proof analysis in the influence to which fair nature lateness of a customer attains to the re-purchase intention to this store of customer satisfaction and future by service recovery process for an object in the customer who held service failure recovery experience in the domestic large-sized rate influence store.

• 한국산업경영시스템학회:학술대회논문집
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.37-44
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• 2002

In order to review the failure rate of PC monitor under normal environmental conditions, we experimented for various levels of each factors, e.g Power on/off, DPM mode, using voltage, Incoming Surge, Torque strength etc. According to the results of experiment and SN ratios we investigated that the causes of the failure for the horizontal output TR of monitor are Mode change, dispersion of Torque and $h_{FE}$ and these are critical effect. For the new reliability test we suggested that strengthened part tests In IQC branch, Torque change controls in the TR specification are necessary.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.81-83
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• 2005

The Reactor Protection System (RPS) is a very important system in a nuclear power plant because the system shuts down the reactor to maintain the reactor core integrity and the reactor coolant system pressure boundary if the plant conditions approach the specified safety limits. This paper describes the unavailability assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system. and applied to the reactor protection system being developed in Korea.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.105-112
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• 2006

The main function of a reactor protection system is to maintain the reactor core integrity and the reactor coolant system pressure boundary. Generally, the reactor protection system adopts the 2-out-of-m redundant architecture to assure a reliable operation. This paper describes the safety assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures such as the random hardware failures, common cause failures, operator errors, and the fault tolerance mechanisms implemented in the reactor protection system. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system, and applied to the reactor protection system being developed in Korea to identify design weak points from a safety point of view.