• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.361-365
• /
• 2007

자연재난은 발생원인에 따라 바람, 강우, 적설, 파고등으로 구분할 수 있다. 이러한 재난원인은 자연현상의 일부로 발생하였으나, 경제가 발전함에 따라 과거에 비해 재해에 안전한 사회를 요구하게 되어 재해저감을 위한 투자와 방재정책 개발의 필요성이 증대되고 있다. 기존에는 자연재난을 저감시키기 위하여 연최대치 강우를 통계 분석하고 강우-유출관계를 이용하여 장래에 발생할 홍수량을 예측하여 자연재난을 저감할 수 있도록 설계하는 것이 일반적인 재난저감계획 수립으로 간주되었다. 그러나, 재해예방을 위해서는 과거에 발생한 재난의 지역적 특성을 분석하여 재난발생 위험과 피해규모를 파악함으로써 재난계획 수립의 기초자료로 활용할 필요성이 있다. 이러한 자연재난에 대한 대책수립은 국가차원에서 필요하며 이를 위해서는 지역별 안전도 평가의 필요성이 증가하게 된다. 그러나 이러한 연구를 수행하기 위해서는 방대한 자료를 바탕으로 풍수해 발생특성을 분석하는 연구와 지자체 또는 지역별 재난피해저감 능력을 수치적으로 나타낼 필요성이 있다. 따라서, 공학적인 면뿐만 아니라 행정적인 면을 동시에 고려하는 학제간 연구가 필요하다. 본 연구에서는 우리나라에서 주로 발생하는 풍수해에 의한 자연재난 특성을 파악하고 재난발생 확률을 고려한 재난피해규모와 재난피해 저감능력을 비교하여 전국 234개 지자체별 지역 및 시설물별 안전도를 평가하고자 한다. 과거 10년간 재해연보에 수록된 지자체별 피해현황을 지자체별 특성을 고려하여 분석, 지자체별 연평균 피해규모를 소방방재청의 지역별 안전도 지침서에 의거, 10등급으로 분석하였다. 또한, 지자체별로 투자우선순위 및 방재예산편성의 효율성 극대화를 위해 지자체별 시설물별 피해현황을 분석하는 기법을 개발하여 지자체별 시설물별 안전도 진단지표를 설정하였다. 분석된 결과는 지자체별 시설물별 재해저감을 위한 풍수해저감 종합계획 재난보험제도 도입등의 기초자료로 적용될 수 있다.로 나타났다. 이는 두 흐름에 의해 와(vortex)가 크게 형성되어 하상의 세굴에 영향을 미치기 때문으로 판단되었다.보다 본질부가 차지하는 면적이 월등히 적고 제1차 및 제2차섬유가 차지하는 면적이 많았다. 따라서 고섬유함량인 대마의 품종개량에 있어서는 가능한 한 본질부가 차지하는 면적은 축소시키고 제1차 및 제2차섬유가 차지하는 면적은 증대시켜야 할 것으로 본다.우리 나라 수도의 작기는 앞으로 당기는 것이 좋다고 고찰된다. 6. 우리 나라의 현행 수도작기로 본 기온 및 일조조건은 수도의 분얼전기에 대해서는 호조건하에 놓여 있으나, 분얼후기인 7월 중ㆍ하순 경의 일조부족과 고온다습조건은 병해, 특히 도열병의 유발원인이 되고 있다. 7. 우리 나라의 현행수도작기로 본 전국각지의 수도의 출수기는 모두 일조시간이 적은 부적당한 시기에 처해 있다. 8. 출수후 40일간의 평균기온에 의한 적산온도 88$0^{\circ}C$의 출현기일은 수원에서 8월 23일이었고, 년간편차를 고려한 안전출수기일은 8월 19일로서 적산온도면에서는 관행 출수기일은 약간 늦다고 보았다. 9. 등열기의 평균기온에 의한 적산온도는 현행 수도작기로서는 최종한계시기에 놓여 있으며, 평균기온의 년간편차와 우리 나라의 최저기온이 낮은 점을 고려할 때, 현행출수기는 다소 늦은 것으로 보았다. 10. 생육단계별의 수도체내의 질소함량은 영양생장기의 질소함량이 과다하였으며, 출수 이후에 영양조락을 여하히 방지하느냐가 문제된다고 보았다. 11. 수리불안전답 및 천수답이 차지하는 전답면적의 비율은 차차 감소되고 있는데, 이와 전체 10a당 수량의 증가율과의 상관계수를 산출하였는데, 수리불안전답과의 상관계수 (4)는 +0.525였으며, 천수답과는 r=+0.832, 그리고 수리불안전답과 천수답을 합계한 것과의 상관계수 (r)는 +0.841로서 후2자와는 고도의 정(+) 상관을 보여 천수답이 차지하는 면적비율이 작

• Tuberculosis and Respiratory Diseases
• /
• v.62 no.1
• /
• pp.11-18
• /
• 2007

Background: Patients with chronic obstructive pulmonary disease (COPD) have often been reported to suffer from depression and anxiety possibly due to the exacerbation, hospitalization and mortality of COPD. However,scarce data are available in Korea. This study assessed degree of depression and anxiety, and evaluated the factors associated with depressive symptoms in COPD. Methods: The cross-sectional data on the lung function measurements, smoking behavior, body mass index (BMI), age, gender, depressive symptoms using Beck Depression Inventory (BDI) and anxiety using the State-Trait Anxiety Inventory (STAI) were evaluated in 72 outpatients with COPD and 50 controls without underling lung diseases from September, 2005 to October, 2006 in the Ewha medical center. Results: 1) The age, body mass index (BMI) and serum albumin levels were similar in the patients and controls. The BDI scores (16(0-37) vs. 12(1-30), p=0.001) and the prevalence of depression (36% vs. 6%, p<0.0001) were higher in the COPD patients than in the controls. In the COPD group, the prevalence of depression increased with increasing GOLD stage (p=0.008). The prevalence was 18%(4/22), in mild cases, 30%(6/20) in moderate cases, 52%(13/25) in severe cases and 60%(3/5) in very severe cases. 2) The SAI and TAI scores were higher in the COPD patients (44(20-67) and 47(20-66)) than in the healthy controls (39(26-65) and 44(33-90)). There were a significant correlation between the depression and anxiety scores (p<0.001). 3) A lower BMI, lower postbronchodilator $FEV_1$, current smoking behavior and severity of COPD were univariately associated with the depressive group in COPD, 4) while multivariate logistic analysis revealed only the severe-to-very severe group (OR 3.9, 95% CI 1.2 to 12.9) to be independently associated with depressive symptoms. Conclusion: COPD is strongly associated with depression and anxiety. Therfore, screening for psychological problems in COPD patients is essential, particularly in patients with severe-to-very severe COPD.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.6
• /
• pp.18-28
• /
• 2015

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of U-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D, agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

• Tuberculosis and Respiratory Diseases
• /
• v.50 no.5
• /
• pp.557-567
• /
• 2001

Background : Tumor angiogenesis is required for tumor growth and metastasis. In this study, we investigated the correlation between the intensity of angiogenesis and stage, nodal status, histologic type, metastasis and survival rate of non-small cell lung cancer. Method : Formalin fixed, paraffin embedded surgical specimens of 45 patients who had surgically resected primary non-small cell lung cancers without pre or post operative adjuvant chemotherapy or radiotherapy were examined. The microvessel count(MVC) was demonstrated by immunohistochemical staining for CD31(platelet endothelial cell adhesion molecule, PECAM). Results : Microvessel counts(MVCs) in stage IIIA and IIIB were higher than in stage I and II(p<0.05). The MVC in patients with lymph node metastasis was higher than that in patients without lymph node metastasis, although the difference was not statistically significant(p>0.05). However, in adenocarcinoma, the MVC in patients with lymph node metastasis was significantly higher than that seen in patients without lymph node metastasis(p<0.05). The MVC in adenocarcinoma was higher than that in squamous cell carcinoma(p<0.05). The difference between the MVCs of adenocarcinoma and squamous cell carcinoma was not statistically significant in stage I and II or N0 stage(p>0.05). However, in stage IIIA and IIIB or N1~3 stage, the MVC in adenocarcinoma was higher than that in squamous cell carcinoma(p<0.05). MVC was more increased when metastasis developed within 12 months. In the same histologic type and stage, the duration of survival time in patients with high MVC was shorter than in patients with low MVC, however the difference was not statistically significant(p>0.05). The survival rate in patients with high MVCs was lower than that in patients with low MVCs(P<0.05). Conclusion : In non-small cell lung cancer, MVC correlated relatively well with pathologic stage, nodal status(limited in patients with adenocarcinoma), histologic type, postoperative metastasis and survival rate. However, in the same histologic type and stage, MVC was not significantly related to the duration of survival. Therefore the assessment of the intensity of angiogenesis in non-small cell lung cancer may be helpful in predicting prognosis and in selecting patients for systemic adjuvant therapy of potential metastasis according to the results.

• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.1
• /
• pp.28-40
• /
• 2010

Purpose: The aim of this retrospective study was to provide long-term data about the correlation between multifactorial local factors and the survival of implants. Material and methods: During 19 years (1991 to 2009), 2796 implants were placed in 879 patients. From dental charts and radiographs, the following data were collected: patient's age at implant placement, gender, implant system, surface, length, diameter, location of implant placement, bone quality, primary stability, type of prosthesis. The correlations between these data and implant survival were analyzed. Statistical analysis was performed using Kaplan-Meier survival analysis, Chi-square test, odds ratio. Results: 1. Among the 2796 implants, 150 implants failed that resulted in a cumulative survival rate of 94.64%. The cumulative survival rate of smooth surface implants (91.76%) was lower than rough surface implants (96.02%). 2. Anatomic location, implant surface, diameter of smooth surface implant, primary stability, type of prosthesis, patient's age and gender were significantly associated with implant survival (P < .05). 3. No significant difference in implant survival was found in relation to the following factors: implant length, bone quality, diameter of rough surface implants and type of rough surface according to implant manufacturer (P < .05). Conclusions: Local factors such as anatomic location, implant surface, diameter of smooth surface implant, primary stability and type of prosthesis have a significant effect on implant survival.

• Tuberculosis and Respiratory Diseases
• /
• v.63 no.1
• /
• pp.59-66
• /
• 2007

Background: Surgical lung biopsy is required to establish the etiology and stage of interstitial lung disease(ILD). and this procedure can be safe and meaningful for making clinical decisions. We wanted to determine the safety of surgical lung biopsy(SLB) in patients with interstitial lung disease(ILD). Methods: We conducted a retrospective review of 40 patients with suspected ILD and they underwent surgical lung biopsy from January 2001 to June 2006 at Chungnam University Hospital. We analyzed retrospectively according to their age, gender, pulmonary function, chest tube duration, the arterial blood gases, the procedural technique, and the requirement for supplemental oxygen and mechanical ventilation(MV) at the time of SLB. Results: The mean age of the patients was 56.4${\pm}$16.13 years(range: 21 to 77 years). Overall, the 30-day and 90-day mortality rates were 15% and 20%, respectively. The predictors of perioperative mortality were either the need for mechanical ventilation(MV) at the time of SLB or the need for supplemental oxygen prior to undergoing SLB. Among the 32 patients who were 90-day survivors, the proportion of those patients using the oxygen supplement was 28.1% (n=9). All 8 patients who were 90-day non-survivors used oxygen supplement (p=0.000). The use of the MV was 12.5% (n=4) in the 90-day survivors (n=32) and 62.5% (n=5) in the 90-day non-survivors (n=8); there was a significant difference between the 90-day survivors and non-survivors (p=0.000). Conclusion: Patients who require MV and supplemental oxygen are associated with an increased risk for death following SLB.

• Korean Chemical Engineering Research
• /
• v.56 no.2
• /
• pp.169-175
• /
• 2018

This study deals with a process for the recovery of hydrogen isotopes from methane ($CQ_4$) and water ($Q_2O$) containing tritium in the nuclear fusion exhaust gas (Q is Hydrogen, Deuterium, Tritium). Steam Methane Reforming and Water Gas Shift reactions are used to convert $CQ_4$ and $Q_2O$ to $Q_2$ and the produced $Q_2$ is recovered by the subsequent Pd membrane. In this study, one circulation loop consisting of catalytic reactor, Pd membrane, and circulation pump was applied to recover H components from $CH_4$ and $H_2O$, one of $CQ_4$ and $Q_2O$. The conversion of $CH_4$ and $H_2O$ was measured by varying the catalytic reaction temperature and the circulating flow rate. $CH_4$ conversion was 99% or more at the catalytic reaction temperature of $650^{\circ}C$ and the circulating flow rate of 2.0 L/min. $H_2O$ conversion was 96% or more at the catalytic reaction temperature of $375^{\circ}C$ and the circulating flow rate of 1.8 L/min. In addition, the amount of $CQ_4$ generated by Korean Demonstration Fusion Power Plant (K-DEMO) in the future was predicted. Then, the treatment process for the $CQ_4$ was proposed and HAZOP (hazard and operability) analysis was conducted to identify the risk factors and operation problems of the process.

• Journal of Chest Surgery
• /
• v.37 no.5
• /
• pp.410-415
• /
• 2004

Background: In the operation for coronary artery stenosis, the procedures for mitral regurgitation are restricted to cases of more than moderate mitral regurgitation or for the lesions in leaflets. This is based on the belief that the less than mild regurgitation are a form of reversible change results from ischemia with coronary artery stenosis. We studied the changes and prognostic factors of mitral regurgitation in patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone. Material and Method: We reviewed the medical records of 90 patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone by a single surgeon from Jan. 1995 to Dec. 2002, We grouped the patients according to the postoperative changes of mitral regurgitation, and then we statistically compared the findings of echocardiogram between preoperative and last follow up. Result: There were 24 cases with progression of mitral regurgitation, 12 cases without changes, 54 cases with improvements of mitral regurgitation in total 90 patients. The bypass to LAD was proven as the significant prognostic factor of mitral regurgitation. The preoperative end diastolic left ventricular volume index were higher in aggravated group with 105.38$\pm$38.89 $m\ell$ compared to 71.75$\pm$28,45 $m\ell$ in improvement group, and 84.00$\pm$11.66 $m\ell$ in no change group. The grade of preoperative mitral regurgitation did not show significant differences among the groups. Conclusion: The mitral regurgitation in patient with coronary artery stenosis can be improved after the coronary artery bypass surgery alone. However, the expectation of improvements based on the degree of preparative mitral regurgitation can not be justified, therefore, the procedures for mitral regurgitation should be aggressively considered even in the cases of mild mitral regurgitation. Also, further study should be performed to identify the exact prognostic factors of mitral regurgitation including the left ventricular volume index, and whether the left anterior descending artery has been bypassed.

• Journal of Chest Surgery
• /
• v.37 no.5
• /
• pp.416-422
• /
• 2004

Acute renal failure (ARF) is a common postoperative complication after the cardiac surgery. Postoperative ARF have various causes, and are combined with other complications rather than being the only a complication. It deteriorates the general condition of the patient, and makes it difficult to manage the combined complications by disturbing the adequate medication and fluid therapy. We have planned this study to evaluate the effects of postoperative ARF after the on-pump coronary artery bypass surgery (CABG) on the recovery of patients and identify the risk factors. Method and Material: We reviewed the medical records of patients who underwent CABG with cardiopulmonary bypass by a single surgeon from Jan. 2000 to Dec. 2002, We checked the preoperative factors; sex, age, history of previous serum creationism over 2.0 mg/㎗, preoperatively last checked serum creatinine, diabetes, hypertension, left ventricular ejection fraction, intraoperative factors; whether the operation is an emergent case or not, cardiopulmonary bypass time, aortic cross clamp time, the number of distal anastomosis, postoperative factors: IABP. Then we have studied the relations of these factors and the cases of postoperative peak serum creatinine over 2.0 mg/㎗. Result: There were 19 cases with postoperative peak serum creatinine over 2.0 mg/㎗ in a total 97 cases. Dialysis were done in 3 cases for ARF with pulmonary edema and severely reduced urine output. There were 8 cases (42.1%) with combined complications among the 19 patients. This finding showed a significant difference from the 5 cases (6,4%) in the patients whose creatinine level have not increased over 2.0 mg/㎗. The mortalities are different as 1.3% to 10.5%. The risk factors that are related with postoperative serum creatinine increment over 2.0 mg/㎗ are diabetes, the history of previous serum creatinine over 2.0 mg/㎗ and left ventricular ejection fraction. Conclusion: Postoperative ARF after the on-pump CABG is related with preoperative diabetes, the history of previous serum creatinine over 2,0 mg/㎗ and left ventricular ejection fraction. Postoperative ARF could De the reason for increased rate of complications and mortality after on-pump CABG. Therefore, in the patients with these risk factors, the efforts to prevent postoperative ARF like off-pump CABG should be considered.

• Journal of Chest Surgery
• /
• v.40 no.6 s.275
• /
• pp.414-419
• /
• 2007

Background: Replacing the ascending aorta is a standard surgical option for treating acute type A aortic dissection. But replacing the aortic arch has recently been reported as an acceptable procedure for this disease. We compared the effects of aortic arch replacement for treating acute type A aortic dissection with the effects of ascending aortic replacement. Material and Method: From 2002 to 2006, 25 patients undewent surgical treatment for acute type A aortic dissection, 12 patients undewent ascending aortic replacement and 13 patients underwent aortic arch replacement. Among the aortic arch group, an additional distal stent-graft was inserted during the operation in 5 patients. 19 patients (11 arch replaced patients and 8 ascending aortic replaced patients) were followed up at the out patient clinic for an average of $756{\pm}373$ days. All the patients undewent CT scanning and we analyzed their distal aortic segments. Result: 4 patients who underwent ascending aortic replacement died, so the overall mortality rate was 16%. Among the 11 long term followed-up arch replacement patients, 2 patients (18.1 %) developed distal aortic dilatation and one of them underwent thoracoabdominal aortic replacement later on. However, among the 8 the ascending aortic replaced patients, 5 patients (62.5%) developed distal aortic dilatation. Conclusion: Aortic arch replacement is one of the safe options for treating acute type A aortic dissection. Aortic arch replacement for treating acute type A aortic dissection could contribute to a reduced distal aortic dilatation rate and fewer secondary aortic procedures.