• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.617-625
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• 2012

Non-contact detection of internal defects in a rail using ultrasonic waves is discussed in this paper. Cracks in a rail may be a cause of a serious railway accident such as derailment if left undetected. Concurrent rail inspection method based on ultrasonic testing using piezoelectric transducers has several limitations as it should keep physical contact with the rail. This work suggests a non-contact detection of internal defects in a rail using ElectroMagnetic Acoustic Transducers (EMAT) which can produce and measure ultrasonic waves in a rail without any couplant. The EMATs for rail inspection are designed and fabricated and their working performance is verified through a series of experiments on various types of internal defects in test rails. The effect of lift-off between the transducers and the rail on the generated signals is also discussed.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.29-33
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• 2010

본 연구는 Kerosene-LOx를 추진제로 하는 가스발생기용 스월 동축형 인젝터의 리세스 길이에 따른 내부 유동의 특성 파악을 목표로 하였다. 리세스 길이는 분무 안정성, 내부 LOx post 손상 등에 영향을 미치는 중요한 요소로 액막두께, 매니폴드 압력 측정 및 내부 유동 가시화를 통해 리세스의 영향을 분석하였다. 또한, 리세스 길이에 따른 내부 또는 외부 인젝터 각각의 분무특성도 살펴보았다.

• Tuberculosis and Respiratory Diseases
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• 제78권4호
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• pp.440-444
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• 2015

Gastric mucosal damage by iron pills is often reported. However, iron pill aspiration is uncommon. Oxidation of the impacted iron pill causes bronchial mucosal damage that progresses to chronic bronchial inflammation, necrosis, endobronchial stenosis and rarely, perforation. We reported a case of a 92-year-old woman with chronic productive cough and significant left-sided atelectasis. Bronchoscopy revealed substantial luminal narrowing with exudative inflammation of the left main bronchus. Bronchial washing cytology showed necroinflammatory exudate and a small amount of brown material. Mucosal biopsy showed diffuse brown pigments indicative of ferrous pigments, crystal deposition, and marked tissue degeneration. After vigorous coughing, she expectorated dark sediments and her symptoms and radiological abnormalities improved. There are a few such reports worldwide; however, this was the first case reported in Korea. Careful observation of aspiration-prone patients and early detection of iron pill aspiration may prevent iron pill-induced bronchial injury.

• 대한한방내과학회지
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• 제25권3호
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• pp.602-608
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• 2004

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia which results from one or both of decreased insulin secretion and increased insulin resistance. Chronic hyperglycemia causes damage to the eyes, kidneys, nerves, heart and blood vessels. The major goal in treating diabetes mellitus is controlling elevated blood sugars without causing abnormally low levels of blood sugar. A 67-year-old woman was admitted with hyperglycemia, thirst, Lt. leg numbness and both leg weakness. The patient was diagnosed as So-gal(消渴) due to dry ness-heat based on yin-deficiency(陰虛燥熱) through oriental medicine and NIDDM through western medicine. The patient was treated with oriental and western medicines. Specifically herbal medicine(Gamijihwangtang), acupuncture, moxa theraphy were used as well as oral medications. Clinical symptoms improved and hyperglycemia dramatically stablized.

• Earthquakes and Structures
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• 제10권5호
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• pp.1181-1212
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• 2016

Fragility and loss functions are developed to predict damage and economic losses due to earthquake loading in Reinforced Concrete (RC) structural components with smooth rebars. The attention is focused on external/internal beam-column joints and ductile/brittle weak columns, designed for gravity loads only, using low-strength concrete and plain steel reinforcing bars. First, a number of damage states are proposed and linked deterministically with commonly employed methods of repair and related activities. Results from previous experimental studies are used to develop empirical relationships between damage states and engineering demand parameters, such as interstory and column drift ratios. Probability distributions are fit to the empirical data and the associated statistical parameters are evaluated using statistical methods. Repair costs for damaged RC components are then estimated based on detailed quantity survey of a number of pre-70 RC buildings, using Italian costing manuals. Finally, loss functions are derived to predict the level of monetary losses to individual RC components as a function of the experienced response demand.

• 한국안전학회지
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• 제21권2호
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• pp.1-6
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• 2006

It is well known that pipelines have the highest capacity and are the safest and least environmentally disruptive form of transporting oil and gas. However, pipeline damage caused by both internal and external corrosion is a major concern threatening the reliability of oil and gas transportation and the soundness of the pipeline structure. In this study, we estimate the allowable damage by comparing the ASTM B31G code to a modified theory considering diverse detailed corrosive forms. The ASTM B31 G code has been developed as the evaluation method for reliability and incident prevention of damaged pipelines based on the amount of loss due to corrosion and the yield strength of materials. Furthermore, we suggest a method for estimating the expected life span of used pipelines by utilizing the reliability method based on major variables such as the depth and length of damage and the corrosion rate affecting the life expectancy of the pipelines.

• 한국세라믹학회지
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• 제35권12호
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• pp.1343-1350
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• 1998

A study is made of mechanical properties of unglazed matrix as a funtion of sintering temperature and crack patterns in layer structur pottery consisting of glaze and substrate and in matrix which is sintered at 120$0^{\circ}C$ and 130$0^{\circ}C$ respectively. The mechanical properties of matrix are increased due to density and vitrification to 130$0^{\circ}C$ The interface of glazed bilayer reveals the reactive intermediate layer. Herzian indentation testing is used to investigate the evolution of damage modes as a function of load. In the materials sintered at 120$0^{\circ}C$ quasi-plastic deformation is developed at the matrix and the cone-like cracks initiate at the glazing top surface and additionally upward-extending transverse cracks initiate at the internal in-just initiate at the glazing top surface which pass through the interface with increasing of indentation load. Finally the dominant damage mode shifts from substrate quasi-plasticity to coating fracture with increasing sintering temperature.

• 대한조선학회논문집
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• 제29권4호
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• pp.179-192
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• 1992

연속해 손상역학 분야의 열역학적 정식화 과정에 따라 연성재료의 탄소성-손상 구성방정식을 유도하였다. 이때, 재료 내부의 비가역적인 열역학적 상태변화를 표현하는 소성변형, 손상진전 등의 물리적현상을 내부상태변수로 간주하였다. 이 새로운 구성방정식 모형을 실제 문제에 적용함으로써 연성재료의 탄소성 거동 뿐만 아니라 재료의 자체가 손상을 입어 약화되는 과정 까지도 합리적으로 예측 가능함을 확인할 수 있었다.

• 대한한방내과학회지
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• 제29권1호
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• pp.200-218
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• 2008

Objectives : The purpose of this study was to investigate the effects of Injinchunggan-tang (Yinchenchinggan-tang) on DMN-induced liver damage by applying proteomics. Materials and Methods : Sprague-Dawley rats were used in this experiment and were divided into the normal group (normal saline), the control group (DMN) and the sample group (DMN+IJCGT). DMN was injected i.p. once a day three times a week for 3 weeks in the control group. Normal saline instead of DMN was administered to the normal group. In the sample group, Injinchunggan-tang (Yinchenchinggan-tang) extract was orally administered once a day for 10 days after DMN was induced. The livers of each group were processed and analyzed by histology, Western blot, $Oxyblot^{TM}$, CBB and 2-dimensional electrophoresis. Results : In the histological findings of the liver, IJCGT reduced collagen deposition and liver damage in DMN-induced hepatic fibrosis. IJCGT increased MMP-13 protein production assessed by western blot. Protein oxidation induced by DMN treatment was decreased by IJCGT. In the 2-dimensional electrophoresis finding, the level of the increased proteins induced by DMN treatment such as GRP 75, 58kDa glucose regulated protein and heat shock 70kDa protein 5 were decreased by IJCGT. IJCGT was considered to have the protective effects on hepatotoxicity induced by DMN. In the 2-dimensional electrophoresis finding, the level of increased oxidized proteins such as heat shock 70 protein, mitochondrial malonyltransferase, calreticulin precursor, actin, NADP-isocitrate dehydrogenase, ankyrin repeat and SOCS box protein 11 were decreased by IJCGT. IJCGT was considered to have protective effect on the protein production induced by DMN treatment. Conclusion : Injinchunggan-tang (Yinchenchinggan-tang) exerts an inhibitory effect against the fibrosis and protein oxidation induced by DMN treatment in the rat liver. IJCGT was considered to have protective effects on the hepatotoxicity and protein production induced by DMN treatment.

• 대한본초학회지
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• 제22권4호
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• pp.145-153
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• 2007

Objective : Although chronic non-bacterial prostatitis is a common disease, it is very difficult to treat effectively. Toosendan fructus(TOF) has been traditionally used in treatment of abdominal pain and parasite. In this study, we investigated the therapeutic effects and action mechanism of Toosendan fructus (TOF) in the rat model of non-bacterial prostatitis induced by castration and testosterone treatment. Method : Eight-month-old rats were treated with $17{\beta}$-estradiol after castration for induction of experimental non-bacterial prostatitis, which is similar to human chronic prostatitis in histophatological profiles. Toosendan fructus(TOF) and testosterone were administered as an experimental specimen and a positive control, respectively. The prostates were evaluated by histopahological parameters including the epithelial score and epithelio-stromal ratio for glandular damage. Also, the prostates were observed by hematological alterations of WBC, RBC, hemoglobin, hematocrit and platelet. Results : While prostates of control rats revealed severe acinar gland atrophy and stromal proliferation, the rats treated with Toosendan fructus(TOF) showed a diminished range of the tissue damage. Epithelial score was improved in Toosendan fructus(TOF) than that of the control. The epithelio-stromal ratio was lower in Toosendan fructus(TOF) when compared to that of the control. Also, the examination of bloods were not observed hematological change. Conclusions : These findings suggest that Toosendan fructus(TOF) may protect the glandular epithelial cells and may take hematological safety. We concluded that Toosendan fructus(TOF) may could be a useful remedy agents for treating the chronic non-bacterial prostatitis.