• 한국압력기기공학회 논문집
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• 제15권2호
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• pp.1-8
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• 2019

The integrity of the Reactor Pressure Vessel (RPV) is affected by the neutrons bombarding the vessel wall leading to embrittlement. This irradiation-induced embrittlement leads to reduction in the fracture toughness of RPV materials. This paper presents a comparative study of typical Optimized Power Reactor (OPR)1000 reactor pressure-temperature (P-T) limit curves using the pre-2006 American Society of Mechanical Engineers (ASME) editions used in the power plant and the current ASME edition of 2010. The current ASME Code utilizes critical reference stress intensity factor based on the lower bound of static, while the Pre-2006 ASME editions are based the critical reference stress intensity factor based on the lower bound of static, dynamic and crack arrest. Model-Based Systems Engineering approach was used to evaluate ASME Code Section XI Appendix G for generating the P-T limit curves. The results obtained from this analysis indicate decrease in conservatism in P-T limit curves constructed using the current 2017 ASME code, which can potentially increase operational flexibility and plant safety. Hence it is recommended to use ASME code edition after 2006 be used in all operating nuclear power plants (NPPs) to establish P-T limit curve.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.338-345
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• 2000

In this study, applicability of PMT in domestic area and test procedure were studied. At six test holes of three construction sites in Pusan, PMT using Elastometer-200 type was done. The problems during test were investigated and the test results were analysed. Limit pressure, p$\sub$ι/ could be determined by p- Δv/v method. Using PMT results, marine soil in Pusan could be classified approximately. Net limit pressure value was in the range of 6.4 ∼ 22.5 kg/$\textrm{cm}^2$ in clay, 2.2 ∼ 30.0 kg/$\textrm{cm}^2$ in sand, 13.0 ∼ 58.0 kg/$\textrm{cm}^2$ in weathered soil and 47.0 ∼ 190.0 kg/$\textrm{cm}^2$ in weathered rock. Also, E$\sub$m//p$\sub$ι/ value was in the range of 2.4 ∼ 7.0 in clay, 2.6 ∼ 12.1 in sand, 6.8 ∼ 17.1 in weathered soil and 7.2 ∼ 29.6 in weathered rock.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.201.1-201
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• 2002

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.175-182
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• 2001

The PMT test results are compared with other in situ test such as Standard Penetration Test (SPT), Cone Penetration Test (CPT), Field Vane Test (FVT) and the laboratory test in order to investigate the correlationships for the strength parameters obtained from Busan and Incheon areas. Many proposed correlation formulas also make a comparative study and new correlation formulas for domestic soils are introduced. Limit pressure ( $P_1$) could be determined by P-log($\Delta$V/V) and Relative volume Method. PMT for the granular soils showed relatively high correlation with SPT, while CPT has good correlation with PMT for cohesive soil. The predicted undrained shear test ( $S_{u}$) by the PMT test results for Incheon and Busan samples showed low correlativity with proposed equations, therefore, new correlation formulas are proposed for domestic soils.s.

• 전기학회논문지P
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• 제59권1호
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• pp.58-63
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• 2010

In this paper, we proposed a wearable respiration measurement system with textile capacitive pressure sensor. Belt typed textile capacitive pressure sensor approach of respiration measurement, from which respiration signatures and rates can be derived in real-time for long-term monitoring, are presented. Belt typed textile capacitive pressure sensor has been developed for this measurement system. the distance change of two plates by the pressure of motion has been used for the respiration measurement in chest area. Respiration rates measured with the textile capacitive pressure sensor was compared with standard techniques on 8 human subjects. Accurate measurement of respiration rate with developed sensor system is shown. The data from the method comparison study is used to confirm theoretical estimates of change in capacitance by the distance change. The current version of respiratory rate detection system using textile capacitive pressure sensor can successfully measure respiration rate. It showed upper limit agreement of $3.7997{\times}10^{-7}$ RPM, and lower limit of agreement of $-3.8428{\times}10^{-7}$ RPM in Bland-Altman plot. From all subject, high correlation were shown(p<0.0001). The proposed measurement method could be used to monitor unconscious persons, avoiding the need to apply electrodes to the directly skin or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range and quality of the rate-finding, broadening the potential application areas of this technology.

• The Korean Journal of Ecology
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• 제17권2호
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• pp.149-157
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• 1994

To investigate the causes of distribution of Kummerowia striata (Thunb.) Schindl. mostly restricted on the roadside and reclaimed land, plant growth was analyzed under different of tread-pressures: $P_1$(10 times/day, $16.34Kg/cm^2$), $P_2$(20 times/day, $31.52 Kg/cm^2$), $P_3$(30 times/day, $40.79 kg/cm^2$) and the control $P_c$(0 times/day, $3.73 Kg/cm^2$). The matter production in the $P_1$decreased compared with that in the $P_c$, and those in the $P_2$and $P_3$ continuously decreased so that its length growth gradually decreased and, in particular, the growth of leaves and nodule was suppressed. The number of leaves and roots tended to increase in the $P_2$and $P_3$. The water contents of roots following the increase of tread-pressure increased continuously. Following the increase of tread-pressure, T/R ratio and C/F ratio tended to increase. Kummerowia striata showed the highest growth in the $P_c$ and showed 26% relative growth in the $P_1$compared with that in the $P_c$. This plant showed 8% relative growth in the $P_3$, which is excess to the tread-pressure $21Kg/cm^2$, the limit of growth in the plant. Because this plant grew continuously in the P$_3$, the tread-pressure is regarded as an important factor affecting the roadside distribution of this plant.

• Geomechanics and Engineering
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• 제32권3호
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• pp.335-346
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• 2023

For structures with underground basement walls, the soil-structure-interaction between the side soil and the walls affects the response of the system. There is interest in quantifying the relationship between the lateral earth pressure and the wall displacement using p-y curves. To date, passive p-y curves in available limited studies were assumed elastic-perfectly plastic. In reality, the relationship between earth pressure and wall displacement is complex. This paper focuses on studying the development of passive p-y curves behind rigid walls supporting granular soils. The study aims at identifying the different components of the passive p-y relationship and proposing a rigorous non-linear p-y model in place of simplified elastic-plastic models. The results of the study show that (1) the p-y relationship that models the stress-displacement response behind a rigid basement wall is highly non-linear, (2) passive p-y curves are affected by the height of the wall, relative density, and depth below the ground surface, and (3) passive p-y curves can be expressed using a truncated hyperbolic model that is defined by a limit state passive pressure that is determined using available logarithmic spiral methods and an initial slope that is expressed using a depth-dependent soil stiffness model.

• The Journal of Korean Physical Therapy
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• 제28권1호
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• pp.1-7
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• 2016

Purpose: The aim of this study was to evaluate the effect of Bridge exercise with abdominal drawing-in on static and dynamic balance in patients with stroke. Methods: Forty patients with stroke participated in this study. Participation was randomly assigned to the Bridge exercise group (n=20) and the Bridge exercise with abdominal drawing-in group (n=20). A bio-feedback device was used when patients performed the Bridge exercise with abdominal drawing-in. This training was performed without any motion on the patient's spine and upper belly part, and the pressure was held with the biofeedback device as 40-70 mmHg. Both groups received training 30 minutes per day, three times per week, for four weeks. Weight bearing, anterior limit of stability, and posterior limit of stability for static balance ability were measured, and Berg balance scale (BBS), Timed up and go test (TUG) for dynamic balance ability were also measured. Results: Participants showed significant differences between pre- and post-mediation in terms of weight bearing, anterior limit of stability, posterior limit of stability, Berg balance scale, and Timed up and go test (p<0.05). The Bridge exercise with abdominal drawing-in group showed a more significant increase (p<0.05). Conclusion: According to the results of this study, both exercises were effective for improving the static and dynamic balance ability. However we suggest that the Bridge exercise with abdominal drawing-in is more efficient for increasing balance ability in patients with stroke.

• 한국세라믹학회지
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• 제27권7호
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• pp.841-850
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• 1990

The electrical conductivity of SrTiO3 thick films, which has been prepared by screen printing and sintering on polycrystalline Al2O3 substrates, was determined as a function of oxygen partial pressure and temperature. The data showed that electrical conductivity was proportional to the -1/4th power of the oxygen partial pressure for the oxygen partial pressure range from 10-4-10-8 to 10-20 atm and proportional to Po2+1/4 for the oxygen partial pressure range from 10-6-10-4 to 1atm. And then n-p transition region of electrical conductivity moved to lower oxygen partial pressure region as the sintering temperature of thick film specimens increased under about 140$0^{\circ}C$. These data were consistent with the presence of small amounts of acceptor impurities in SrTiO3 thick film which have been diffused from Al2O3 substrate in the range of solid solubility limit.

• 한국환경농학회지
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• 제26권3호
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• pp.254-258
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• 2007

국내에서 합성, 개발된 유기인계 살충제인 bistrifluron의 물리화학적 특성으로 수용성, 가수분해, 증기압을 미국 EPA와 OECD 방법에 준하여 측정하였다. 수용성은 $25^{\circ}C$에서 30 ppb로 낮았고 가수분해 반감기는 $20^{\circ}C$에서 10.9일(pH 9.0) 이었고 pH 7.0 조건에서는 전혀 분해가 안되었으며, $40^{\circ}C$에서는 20.6일(pH 7.0), 1.5일(pH 9.0) 이었다. 상온$(25^{\circ}C)$에서의 증기압 측정은 시험기간 중 bistrifluron이 검출되지 않아 bistrifluron의 검출한계(50 ng)를 적용하여 계산한 ${\leq}2.05{\times}10^{-8}$ torr를 bistrifluron의 증기압으로 결정하였다. 이 수치를 보면 bistrifluron은 휘발에 의하여 환경에 영향을 미칠 가능성이 낮을 것으로 판단된다.