• Archives of Plastic Surgery
• /
• 제49권1호
• /
• pp.76-79
• /
• 2022

Kienböck disease, a rare disease that can cause chronic pain and motor dysfunction, occurs due to avascular necrosis of the lunate bone, which leads to dislocation of the carpal bone. Among various other etiologies, Kienböck disease can cause closed tendon rupture of the finger. In this report, we introduce a case of total rupture of the second extensor digitorum communis and the extensor indicis proprius tendons caused by undiagnosed Kienböck disease in an elderly female patient.

• 터널과지하공간
• /
• 제22권2호
• /
• pp.77-85
• /
• 2012

피로파괴는 반복적인 하중에 의해 재료 내에 균열이 발생하고, 진전함에 따라 재료의 물성이 약화되어 최종적으로 파괴에 이르는 현상을 말하며, 일반적으로 반복적인 하중이 가해지는 기계나 구조물 등은 피로파괴를 고려한다. 암반구조물의 경우 일반적으로 동적인 반복하중에 의한 피로파괴보다는 정적인 크립에 의한 피로 파괴를 경험하는 경우가 대다수이다. 그러나 압축공기와 같은 물질을 지하에 저장하는 경우 물질의 입 출에 의한 내부 압력의 변화가 발생하기 때문에 지하저장시설이 위치하는 암반과 내부 콘크리트의 동적 피로파괴 특성을 검토해야한다. 본 연구에서는 복공식 지하 압축공기에너지 저장공동 내부에 설치되는 콘크리트 라이닝의 반복굴곡하중에 대한 물성변화와 플러그가 설치된 경계에서의 반복전단하중에 대한 물성변화를 실험적인 방법에 의해 알아보았다. 반복전단시험을 통해 적절한 수직응력에서 평면 인터페이스의 플러그도 역학적인 안정성을 확보할 수 있음을 알 수 있었다. 반복굴곡시험에서는 반복재하에 따른 콘크리트 라이닝의 강도저하 현상을 확인하였으며, 이로부터 S-N 곡선을 구하였다.

• 터널과지하공간
• /
• 제24권1호
• /
• pp.67-80
• /
• 2014

본 연구에서는 임계하균열성장 변수를 구하기 위해 제안된 Wilkins의 시험법을 압열인장시험과 결합하여 화강암의 인장강도, Mode I 파괴인성과 임계하균열성장지수를 동시에 구하였으며 이를 사용하여 암석의 장기거동을 평가하였다. 또한 내부압력을 받는 압축공기저장(CAES) 공동에 대한 장기안정성을 수치해석코드인 FRACOD를 사용하여 해석하였다. 시험 결과 화강암의 임계하균열성장지수(n)는 29.39로 결정되었으며 5 ~ 6 MPa의 내압은 저장공동의 장기안정성에 큰 영향을 미치지 않는 것으로 나타났다. 또한 시험 과정에서 측정한 미소파괴음을 분석한 결과 암석내의 미소균열 생성 및 전파에 따른 암석의 손상을 정량적으로 기술할 수 있었다. 만약, 실내와 동일한 조건으로 현장에서 AE 모니터링을 수행할 경우 AE 모니터링을 통해서 하중을 받는 암석의 현재 상태를 정량적으로 평가하는 것이 가능할 것으로 판단된다.

• 터널과지하공간
• /
• 제23권3호
• /
• pp.241-259
• /
• 2013

충전층을 이용한 열에너지저장 시스템은 자갈이나 콘크리트와 같은 열저장매질과 공기나 오일과 같은 열전달유체를 이용하여 현열에너지를 저장하는 방식으로서, 저장매질의 경제성과 화학적 안정성, 시스템 구축의 용이성 등 많은 장점이 갖는다. 본 연구에서는 충전층을 이용한 열에너지저장 기술에 대하여 개략적으로 소개하고, 이러한 열에너지저장소의 에너지 수지와 성능 효율을 분석하기 위한 수치 모델을 제시하였다. 유한차분법을 이용하여 저장소 내 1차원 비정상 열전달 해석을 수행하였으며, 반복적인 주입과 토출에 따른 충전층의 온도분포와 외부로의 손실 에너지를 계산하였다. 해석모델은 AA-CAES(advanced adiabatic compressed air energy storage)와 연계된 고온의 열에너지저장시스템으로 저장소가 지하암반 내에 위치하는 경우와 지상에 위치하는 경우를 모사하고, 성능효율 및 열손실률을 비교 분석하였다.

• 설비공학논문집
• /
• 제24권8호
• /
• pp.646-655
• /
• 2012

This study is intended to analyze the thermal performance and evaluate the applicability about non-duct type heat recovery ventilation system integrated with window. Eventually, economic analysis of the system is conducted according to building energy saving ratio of it. As results of the thermal performance, the U-factor of the window conducted on the basis of KS F 2278 appears to $1.8W/m^2K$, and the effective heat exchange efficiency of the ventilator conducted on the basis of KS B 6879 appears 49.95% for cooling, 66.89% for heating. In the applicability evaluated by TRNSYS 16, the caes of applying the heat recovery ventilator integrated with window is found to reduce the cooling or heating load by 2.9% or 13.5% than the non-ventilator case. The results of economic analysis taking a side of consumer is verified as the payback is 3 years, and the accumulated earning is 1,408,133 won in terms of '600,000 won/unit' for initial cost, 10 years for useful life of the system.

• Nuclear Engineering and Technology
• /
• 제49권8호
• /
• pp.1669-1679
• /
• 2017

Background: Steam generator (SG) is one of the significant components in the nuclear steam supply system. A variety of SGs have been designed and used in nuclear reactor systems. Every SG has advantages and disadvantages. A brief account of some of the existing SG designs is presented in this study. A high surface to volume ratio of a SG is required in small modular reactors to occupy the least space. In this paper, performance improvement for SGs of integral small modular reactor is proposed. Aims/Methods: For this purpose, cross-grooved microfins have been incorporated on the inner surface of the helical tube to enhance heat transfer. The primary objective of this work is to investigate thermal-hydraulic behavior of the proposed improvements through modeling in RELAP5-3D. Results and Conclusions: The results are compared with helical-coiled SGs being used in IRIS (International Reactor Innovative and Secure). The results show that the tube length reduces up to 11.56% keeping thermal and hydraulic conditions fixed. In the case of fixed size, the steam outlet temperature increases from 590.1 K to 597.0 K and the capability of power transfer from primary to secondary also increases. However, these advantages are associated with some extra pressure drop, which has to be compensated.

• Structural Engineering and Mechanics
• /
• 제77권6호
• /
• pp.753-763
• /
• 2021

Feasibility studies of a reinforced concrete (RC) deep pile foundation system with the compressed air energy storage (CAES) technology were conducted in previous studies. However, those studies showed some technical limitations in its serviceability and durability performances. To overcome such drawbacks of the conventional RC energy pile system, various steel-concrete composite pile foundations are addressed in this study to be utilized as a dual functional system for an energy storage medium and load-resistant foundation. This study conducts finite element analyses to examine the applicability of various composite energy pile foundation systems considering the combined effects of structural loading, soil boundary forces, and internal air pressures induced by the thermos-dynamic cycle of compressed air. On this basis, it was clearly confirmed that the role of inner and outer tubes is essential in terms of reliable storage tank and better constructability of pile, respectively, and the steel tubes in the composite pile foundation can also ensure improved serviceability and durability performances compared to the conventional RC pile system.

• Journal of Preventive Medicine and Public Health
• /
• 제7권1호
• /
• pp.123-130
• /
• 1974

A socio-medical survey was carried out on 1,108 cases of pulmonary tuberculosis who had registered and 220 cases unregistered at Jeonju health center in 1973, during from June 1 to July 31, 1974. As the results of this survey, the following conclusions were obtained. 1. Of the total 1,108 cases of pulmonary tuberculosis there were 708 new cases, while remaining 400 were old cases and rate of registration was 4.0 per thousand person. 2. The highest rate of registration of the newly diagnosed pulmonary tuberculosis could be found in bacteriological examination while 54.4 per cent in X-ray examination. 3. As for the educational status of the tuberculosis patients, primary school graduates contituted the greatest proportion or 64.6 per cent, middle school graduates 13.6 per cent, high school graduates 6.8 per cent and collge graduates only 0.7 per cent. 4. By age group of the cases, at age of 20 to 29 years occupied 23.6 per cent (262 out of 1,108 cases), 17.9 per cent at age of 40 to 49 years. 5. The greatest proportion or 38.4 per cent of the cases had no occupation. 6. The living standard of the patient's household, low class constituted 60.6 per cent of the total households. 7. By distribution of residential area, farming area was 5.0 per thousand person, 4.0 in downtwon and suburban areas. 8. The greatest proportion or 70.0 per cent of positive cases in X-ray examination was unregistered in August, 63.6 per cent in July 1973. 9. 220 out of 1,108 cases(19.9%) were unregistered pulmonary tuberculosis in X-ray and bacteriological examinations. 10. For age groups of unregistered caes, most prevalent age group was 30 to 39. 11. Regarding on the cases of unregistration, 'indifference for disease' occupied highest rate with 31.9 percent' and 'private secret' with 15.7 per cent. 12. Of the total 457 cases drop-outed, there were 78 complete heald cases while remaining 207 inactive.

• 대한세포병리학회지
• /
• 제9권1호
• /
• pp.63-68
• /
• 1998

Fine needle aspiration cytology of "cold" nodules of the thyroid has proved to be of great value in their preoperative diagnosis. Most types of thyroid tumors are readily recognizable from characteristic cellular patterns in the smears of needle aspirates. But follicular neoplasms present some problems because the cytomorphology of the adenomas frequently is same as in carcinoma. For differentiation of benign from malignant follicular neoplasms of the thyroid we tested the usefulness of two objective parameters - nuclear area and perimeter - by morphometry. This study was made on fine needle aspirates from 30 cases with cytologic diagnosis of follicular neoplasm of thyroid. The histologic classification was follicular adenoma in 22 cases and follicular carcinoma in 8 cases. As a reference group we used seven caes with nodular hyperplasia. The smears of aspirates were stained by Papanicolaou method. On each slide 200 randomly selected cells with intact nuclei were measured. The mean value of nuclear area are $25.32{\pm}5.50{\mu}m^2,\;34.08{\pm}7.50{\mu}m^2\;and\;39.97{\pm}6.63{\mu}m^2$ in nodular hyperplasia, follicular adenoma, and follicular carcinoma, respectively. The mean value of perimeter are $19.48{\pm}2.26{\mu}m,\;22.95{\pm}2.65{\mu}m\;and\;24.78{\pm}2.23{\mu}m$ in nodular hyperplasia, follicular adenoma and follicular carcinoma, respectively. The mean nuclear areas and perimeters of cells from follicular adenoma were significantly larger than those from nodular hyperplasia (p<0.05). The mean nuclear areas and perimeters of cells from follicular carcinoma were larger than those from follicular adenoma but the differences are not significant statistically(p>0.05). Therefore, morphometric assessment alone is inadequate to predict malignancy in thyroid aspirates.

• 한국주조공학회지
• /
• 제23권3호
• /
• pp.137-146
• /
• 2003

The main purpose of this study is to investigate the effects of process parameter on alpha-case formation of Ti and TiAl castings. The previous studies showed that the molten titanium is excessively reactive to the refractory oxide mold, resulting in alpha-caes of the titanium castings regardless of composition of titanium alloys. However, the behavior of the alpha-case formation of TiAl alloy is not consistent with conventional titanium alloy. In order to investigate the alpha-case formation of Ti and TiAl castings with process parameter, especially the associated factors of investment mold such as mold material, binder and mold preheating temperature. An attempt has been made to characterize the alpha-case of titanium casting by using optical microscope, EDS, XRD, EMPA and hardness profiles. The formation of the alpha-case on the surface of pure titanium during investment casting was rather by that of solid solution with metallic element from mold material. The required mold strength was obtained with $CaZrO_3$ because of the possibility of using water soluble binder. However, the separation phenomenon between facing and back-up mold materials should be considered. The interfacial reaction of TiAl alloy showed different behavior from that of pure titanium and $Al_2O_3$ was best mold materials. The effect of binder as well as mold material on the formation of alpha-case was significant.