• 한국지역사회생활과학회지
• /
• 제22권4호
• /
• pp.623-635
• /
• 2011

Over the past few decades, the proportion of elderly people with depression in Korea has been rapidly increasing. The purpose of this study is to explore relative effects of health and family factors on geriatric depression. The data sources are from Korean Longitudinal Study of Aging(2008). The Analysis sample consists of 4,040 cases. Analysis results show that there is a significant variability in geriatric depression according to sociodemographic characteristics, health characteristics, and family characteristics. Hierarchical logistic regression analyses are employed to assess the causal relationship between health characteristics and geriatric depression. Model II showed that ADL(exp(B)=1.732), having difficulties due to sight deterioration(exp(B)=1.398), having difficulties due to masticatory force deterioration(exp(B)=1.414), having difficulties due to pain(exp(B)=2.435), and subjective health status(exp(B)=2.010) are reported as predictors of geriatric depression. Namely, the probability of having geriatric depression of the above predictors has been 1.7 times, 1.4 times, 1.4 times, 2.4 times. 2.0 times higher than normal figures. Among health characteristics, pain is the most prevalent factor. Model III showed that as for family characteristics, coresiding with children(exp(B)=1.312) and frequency of contacting with children by phones, letters, or emails(exp(B)=1.477) are reported as predictors of geriatric depression. Key findings are that health factors have larger effects than family factors on geriatric depression.

• 한국철도학회논문집
• /
• 제11권4호
• /
• pp.384-389
• /
• 2008

궤도구성품 중 도상은 레일과 침목으로 전달되는 열차하중을 노반으로 전달하는 중간매개체 역할을 하며, 도상자갈의 열화는 궤도틀림 진전에 직접적으로 영향을 미친다. 본 연구에서는 대형 보선장비(멀티플 타이 탬퍼; MTT; Multiple Tie Tamper)를 사용한 도상다짐작업과 누적통과톤수가 자갈 세립화 및 도상열화의 주요 원인이다. 도상자갈의 열화특성을 파악하기 위하여 시험용 궤도 부설을 통한 현장실험(2장. 실외 실측시험)과 실제의 운행 환경을 모사한 모형실험(3장. 실내 모형실험)을 실시하였고 실제 운용중인 고속선에서 채취한 시료의 파쇄입자 비율과 비교분석하였다.

• 전기학회논문지
• /
• 제61권5호
• /
• pp.711-716
• /
• 2012

To assess the insulation deterioration of stator windings, diagnostic and AC breakdown tests were performed on the eleven high voltage (HV) motors rated at 6kV. After completing the diagnostic tests, the AC overvoltage test was performed by gradually increasing the voltage applied to the stator windings until electrical insulation failure occurred, to obtain the breakdown voltage. Stator winding of motors 1, 3, and 8 failed at above rated voltage at 14 kV, 13.8kV, and 16.4kV, respectively. The breakdown voltage of three motors was higher than expected for good quality windings in 6kV motors. Based on deterioration evaluation criteria, the stator winding insulation of eleven HV motors are confirmed to be in good condition. The turning point of the current, $P_{i2}$, in the AC current vs. voltage characteristics occurred between 5kV and 6kV, and the breakdown voltage was low between 13.8kV and 16.4kV. There was a strong correlation between the breakdown voltage and various electrical characteristics in diagnostic tests including Pi2.

• 콘크리트학회논문집
• /
• 제19권1호
• /
• pp.47-56
• /
• 2007

최근들어 고속도로, 고속철도, 지하철등의 건설이 증가하면서 터널의 건설도 늘어나고 있는 추세이다. 이러한 터널 공사에서 필수적으로 따르는 것이 숏크리트 공정이며 이러한 숏크리트의 시공은 앞으로도 더욱 증가할 추세에 있다. 그러나 숏크리트의 광범위한 시공에도 불구하고 여러 가지 문제점을 내포하고 있는 것이 사실이다. 따라서 본 연구에서는 우리나라 현행 숏크리트의 현황과 문제점을 분석하고, 고품질의 숏크리트 시공을 위하여 실리카퓸 숏크리트의 성능 및 적용성에 대해 분석하였다. 또한 숏크리트의 장기적인 안정성 확보를 위해서는 복합적인 환경조건을 고려한 열화 특성을 파악할 필요가 있다. 본 연구에서는 건습 반복, 동결융해 및 탄산화 등의 열화 인자를 복합적으로 적용한 열화 시험을 수행하였다. 특히, 우수한 강도 증진 효과로 국외에서 많이 사용되고 있는 실리카퓸을 적용하여 혼화재 치환에 따른 숏크리트의 장기 내구 특성을 평가하였다. 복합 열화 시험 결과 실리카퓸을 혼입한 숏크리트는 다른 배합에 비해 가장 양호한 결과를 나타냈고, 실리카퓸은 강도 증진 효과와 함께 강섬유 혼입에 의한 열화 현상을 최소한으로 감소시켜 숏크리트의 장기 내구성을 확보하는데 효과가 있었다.

• Journal of Korean Neurosurgical Society
• /
• 제66권1호
• /
• pp.82-89
• /
• 2023

Objective : Rathke's cleft cysts (RCCs) are nonneoplastic cysts. Most of them are asymptomatic and stable; when symptomatic, RCCs are surgically fenestrated and drained. However, the outcomes remain unclear. The authors evaluated the outcomes of RCC decompression. Methods : Between 2004 and 2019, 32 RCCs were decompressed in a single tertiary institution. The clinical characteristics, intraoperative findings, postoperative complications, and endocrinological and surgical outcomes were retrospectively reviewed. Patients who underwent sequential imaging at least twice and at least 12 months after surgery were included in the analysis. Results : Patients' mean age was 40.8±14.9 years, and 62.5% were women. The mean follow-up duration was 62.3±48.6 months. In 21 patients (65.6%), no residual cysts were identified on postoperative magnetic resonance imaging. Of the 18 patients with preoperative visual field defects, 17 (94.4%) experienced postoperative visual improvement. Postoperative complications included endocrinological deterioration in 11 patients (34.4%), permanent diabetes insipidus in 11 (34.4%), infection in four (12.5%), intrasellar hemorrhage in three (9.4%), and cerebrospinal fluid leak in two (6.3%). Follow-up images revealed cyst recurrence in nine patients (28.1%), an average of 20.4 months after surgery; in three patients, the cysts were symptomatic, and resection was repeated. Multivariable analysis revealed that postoperative endocrinological deterioration was the only independent factor associated with cyst recurrence (p=0.028; hazard ratio, 6.800). Conclusion : Our findings showed that although only cyst fenestration for decompression was performed to preserve pituitary function, more pituitary dysfunction occurred than expected. Besides, the postoperative hormonal deterioration itself acted as a risk factor for cyst recurrence. In conclusion, surgery for RCC should be more careful.

• Computers and Concrete
• /
• 제20권5호
• /
• pp.573-582
• /
• 2017

Chloride-induced cover cracking will aggravate the performance deterioration for RC structures under the chlorideladen environment, which may endanger the safety of structures and occupants. Traditional design method cannot ensure that a definite performance is satisfied. To overcome the defects, a study on the performance-based design method was carried out in this paper. Firstly, the limit state functions were established for the corrosion initiation and cover cracking. Thereafter, the uncertainty analysis was performed to study the effects of random factors on the time-dependent performances. Partial factor formulae were deduced through the first-order reliability method for performance verification. Finally, an illustrative example was presented and the sensitivity of cover depth to other parameters was carried out. It is found that the uncertainties of the random variables have great effects on the required cover depth. It is demonstrated that the performance-based design method can ensure that the target performance can be satisfied and support to formulate a rational maintenance and repair strategy for RC structures under the chloride environment.

• 자원환경지질
• /
• 제52권6호
• /
• pp.617-626
• /
• 2019

이 연구에서는 해남 대흥사 북미륵암 마애여래좌상을 구성하는 석재의 암석학적 특성과 물성을 진단하였다. 이 마애불상은 미문상화강암에 부조되어 있으며, 전체적인 암상은 장석에 포위된 작은 석영 결정들이 미문상 조직을 이루고 있다. 손상도 진단 및 평가 결과, 흑색변색(8.4%)과 균열지수(6.6)에서 높은 훼손율을 보였고, 초음파 속도는 약간 풍화단계의 풍화도지수(평균 0.18)가 산출되었다. 마애불의 표면에 나타나는 손상은 기존 보호각의 영향으로 판단되고, 물성은 자연암반의 구조적 특성과 균열의 직접적인 영향에 의한 것으로 해석된다.

• 한국강구조학회 논문집
• /
• 제28권5호
• /
• pp.325-335
• /
• 2016

국내의 강교 도장 시방에 등재되어 있는 도장계에 대한 공용수명 예측을 위하여 현장 열화도 평가 및 촉진 내후성 시험을 수행하였고, 평가 결과에 대한 회귀분석을 통하여 열화모델을 도출하였다. 현장 적용 실적이 없는 도장계에 대해서는 국외 연구 결과 및 본 연구에서 수행한 촉진 내후성 시험 결과를 참고하여 염화고무계 및 우레탄 마감 도장계의 현장 열화도 평가 결과에 열화도 항목별 조정계수를 적용하여 가상의 평가 결과를 도출한 후에 회귀분석을 실시하였다. 공용수명 예측 결과는 금속용사를 적용하면 도장계의 수명을 일반 도장계 대비 2배 이상 연장시킬 수 있다는 것을 보여주었다.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2011년도 정기 학술발표대회
• /
• pp.91-91
• /
• 2011

The quality of the surface layer in concrete structures plays an important role in the durability of the concrete. The concrete factory products are made as they improve the appearance of the surface and compressive strength in need. A common criterion to judge the quality of concrete products frequently seen in our daily life appears to be "beauty" in terms of consistent shaping. However, as for most concrete curb in such areas where a large amount of anti-freezing agents(NaCl) and ice and snow melting agents(CaCl2) are spread over roads to ensure road safety during the winter season, since deterioration advances from the surface, scaling is seen on the surface concrete due to deterioration which combined freezing damage and salt damage. Especially, In cold northern districts, the spreading amount of deicing salts increases by regulation of studded tire use, and the scaling of the concrete products, the various parts of concrete structures for roads is increasing in recent years. In this study, L-shape concrete curb were targeted, the permeable form method with the commercial permeable sheet was applied to it and the improvements of the quality were examined. By the permeable form method, surface layers got strengthened, which prevented permeation of the deterioration factor from the outside, and the scaling resistance of the upper surface where the permeable sheet was applied improved exceedingly. It will be expected by applying the permeable form method to various concrete products that frost resistance improves and scaling damage decreases.

• 한국대기환경학회지
• /
• 제21권6호
• /
• pp.585-592
• /
• 2005

Nowadays it has been strongly required to control emissions from vehicles specially in diesel engines because of increasing number of vehicle in korea. This research aims to provide with some of deterioration factors on vehicles for emissions characteristics and the test was done on an electronically controlled heavy-duty diesel engine under severe driving conditions such as 1200 driving hours, 220,000 km driving distance and a full load. Under various driving conditions, CO, HC, $NO_{x}$, PM and Soots emissions were estimated under D-13 mode and D-3 mode respectively. CO emission was not changed until 500 running hours, and as engine aging is progressed THC was not changed until 500 running hours but it decreased to about $33\%,\;NO_{x}$ decreased constantly but on the other hand PM increased up to $6.9\%$ during the aging process.