• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.251-256
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• 2009

In this research, we experimentally studied flow characteristic by applying PIV measuring techniques which could measure the point velocity of all flow field and measuring the unsteady velocity of surrounding disk generated in a short time. Time range of great velocity change following quick closing of the slide valve was within 0.1s and the cycle was presumed to be 0.12s as a result of comparison study between the result of point flow field and of existing pressure change. Also, surrounding disk flow inside the circular pipe was closed from the upper part and flow road was getting narrow and advanced to the lower part incidentally quickly there was a tendency that the size of the flow back velocity to the upper part immeadiately after the closure decreased to 4/120s and increased again. There was flow back velocity component in y/D=0.2 lower part by the influence of flow back to the upper part after complete closure and the vortex flow of 0.2D-size near y/D=0.7, x/D=-0.3 was observed.

• The Korean Journal of Nuclear Medicine
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• v.36 no.5
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• pp.306-313
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• 2002

Purpose: Diuretic renography (DR) can be false negative in patients with upper urinary tract obstruction due to low compliance of the renal pelvis. Delayed parenchymal transit (DPT) may be a valuable sign in case of false negative DR. We compared the diagnostic values of DR and DPT during Tc-99m MAG3 diuretic scan in adults with suspected unilateral obstructive uropathy. Materials and Methods: Fifty-four patients(male:female=30:24, age: $40.7{\pm}15.5$ yrs) who underwent Tc-99m MAG3 diuretic scan due to suspicious unilateral obstructive uropathy were analyzed. DR with a $T_{1/2}\;of\;>\;15min$ was considered as positive for obstruction. DPT was considered to be present when there was delayed appearance of radioactivity in the renal pelvis and prolonged retention of radioactivity in the renal parenchyma. The renal area ratio was defined as the ratio of pixel number of hydronephrotic kidney over that of normal contralateral at $1{\sim}2min$ images. Definition of obstruction was improved hydronephrosis after intervention, or aggravated hydronephrosis without intervention. Non-obstruction was defined as unchanged hydronephrosis over 6 months. Results: Twenty-six renal units had obstruction and 28 no obstruction. The sensitivities of DR and DPT were 69% (18/26) and 50% (13/26) respectively. Two renal units with DPT but negative DR showed the renal area ratio of <1.1. Among the 20 obstructive renal units with DPT or positive DR, 13 with DPT had lower renal area ratio than 7 renal units without DPT ($0.97{\pm}0.20\;vs\;1.30{\pm}0.41,\;p<0.05$). Differential renal function was not significantly different between these groups. DPT correctly diagnosed all renal units with non-obstruction (specificity 100%), while the specificity of DR was 89% (25/28). Conclusion: DPT during Tc-99m MAG3 diuretic scan may be a valuable sign in diagnosing urinary obstruction especially in patients with false negative DR and early HN.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.67-74
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• 2006

An unsteady blockage-correction method utilizing wall pressure distribution on the test section has been developed for the wall interference correction of a closed test-section subsonic wind tunnel. The pressure distribution along the test section wall was decomposed into Fourier series and a quasi-steady method based on a measured-boundary-condition method was applied to each Fourier coefficient. The unsteady correction for a complete test period was accomplished by recombining each corrected terms. The present method was validated by appling computed unsteady flows over a cylinder and an oscillating airfoil in the test sections. The corrected results by the present method agreed well with free-air condition.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.9-16
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• 1997

The contingent valuation method(CVM) has been used to evaluate the economic value of nonmarket goods such as forest recreation. There are two commonly used CVM questionnaire formats: open-ended and closed-ended. This study evaluates the net economic value associated with day use downhill skiing, using CVM. A random, on-site survey of skiers in Muju, Korea generated the value estimates. In this paper a nonparametric test is introduced to find whether the difference between value estimates from open-ended and closed-ended formats are significantly different because the distributions of WTPs are non-normally distributed. The results show that the net economic benefits of a skier in Muju varies from \15,131 to \25,332. The closed-ended values were 1.15 to 1.67 times as large as the open-ended values, depending on the model specifications. In nonparametric test the mean WTPs of the open-ended and close-ended applications are significantly different. Its reason may be that closed-ended can be more reducing the incentive for strategic behavior than open-ended question. However, we cannot conclude that the closed-ended method is superior to the open-ended method.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.517-523
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• 2000

Nasopharyngeal closure is a sphincter mechanism between the activities of the soft palate, lateral pharyngeal wall and the posterior pharyngeal wall, which divides the oral cavity and the nasal cavity. It participates in physiological activities such as swallowing, breathing and pronunciation. In case of an error in this mechanism, it is called a nasopharyngeal incompetence. The causes of this error are defects in (1) length, function, posture of the soft palate (2) depth and width of the nasopharynx, (3) activity of the posterior and lateral pharyngeal wall. The purpose of this study is to analyze the nasopharynx of cleft palate patients using lateral cephalograms and at the same time, evaluate the degree of hypernasality of each vowels to find its relationship with nasopharyngeal incompetence. The following results were obtained: 1. The length of the soft palate was markedly short than normal. 2. The adequate ratio was smaller than the normal value. 3. As the adequate ratio decreased, when articulating vowels, anatomic mVPI increased. 4. When articulating each vowels, anatomic VPI was in proportion with the degree of hypernasality. 5. The degree of hypernasality was greater in high vowels(/i/, /u/) than low vowel(/a/). From the above results, it can be concluded that in cleft palate patients, lateral cephalograms can be used effectively in diagnosing and evaluating nasopharyngeal incompetence. The anatomic structure of the nasopharynx has close relation to the degree of hypernasality.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.699-703
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• 2010

최근 우리나라에서도 워터프론트 개발과 주운에 많은 관심을 보이고 있는 실정이며, 현재 한강의 마곡지구에서는 워터프론트 및 주운수로 개발 사업을 수행하고 있다. 마곡 주운수로는 홍수 발생시 한강 수위 상승 전에 갑문을 폐쇄하여 한강의 홍수량이 주운수로 내부로 유입 되는 것을 방지하도록 계획되었다. 그러나 한강수위 상승 전, 마곡주운수로의 갑문 폐쇄 직전에 한강에 운항중인 선박이 주운수로 내로 긴급히 회항을 할 경우가 발생하며, 회항 선박이 안전하게 주운 수로내로의 진입하기 위해서는 갑문의 개폐 정도에 따른 갑문 내부 유속 및 유향에 대한 검토가 필요할 것으로 판단된다. 따라서 본 연구에서는 마곡 주운 수로로 유입되는 빈도별 홍수량에 따른 수로 내부 유황과 갑문 폐쇄 정도에 따른 갑문부 영향을 수리모형 실험과 수치모의를 통하여 분석하였다. 주운수로 유입 빈도별 홍수량이 증가할수록 내부의 유속은 증가 하였으며 100년빈도 홍수시 갑문부에서의 최대 유속은 2.2m/s 나타났다. 홍수시 갑문을 1/3, 1/2, 2/3 폐쇄하였을 경우에 대한 수치 모의 결과 갑문의 2/3 폐쇄시 갑문부 최대 유속은 1/3 폐쇄시에 비하여 약 53-86% 증가 하였으며, 수위는 약 0.2-0.8m 상승하였다. 갑문 폐쇄에 따른 최대 유속은 선박의 운항을 위한 허용 유속과 비교 검토하였다. 이러한 분석을 통하여 선박이 긴급히 주운수로로 회항할 경우에 대한 비상대응계획 및 운영방안 수립에 활용될 수 있을 것이다.

• Tuberculosis and Respiratory Diseases
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• v.65 no.4
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• pp.285-291
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• 2008

Background: We conducted a case-control study to evaluate the potential association between SERPINA1 genotypes ($M1_{Val}$, $M1_{Ala}$, S, and Z) and the risk COPD. Methods: The study population consisted of 93 patients with COPD and 112 healthy controls. The polymerase chain reaction and restriction fragment length polymorphism for detecting the SERPINA1 variants. Results: The M2 allele of the SERPINA1 gene was significantly associated with the risk of COPD in Koreans. The effect of the M2 allele on the risk of COPD was more pronounced in the subgroup<64 years. Conclusion: These results suggest that SERPINA1 polymorphisms may contribute to a genetic predisposition for COPD. However, additional studies with larger sample sizes are required to confirm our findings.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.4
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• pp.293-301
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• 2008

Objective: To evaluate outcomes of patients with non-obstructive azoospermia (NOA) undergoing the testicular sperm extraction (TESE) combined with intracytoplasmic sperm injection (ICSI) with different histopathologic subgroups. Method: A total of 122 embryo-transferred TESE/ICSI cycles were compared among NOA subgroups; Germ-cell aplasia (GA, 40 cycles), Maturation arrest (MA, 32 cycles) and severe hypospermatogenesis (S-HS, 50 cycles). Obstructive azoospermia (OA, 667 cycles) patients were served as a control. TESE/ICSI outcomes such as fertilization rate (FR), clinical pregnancy rate (CPR) and live birth rate (LBR) were evaluated. Results: The 2PN FR of embryo-transferred TESE/ICSI cycle was 58.1% in GA, 42.2% in MA and 48.0% in S-HS, which was significantly lower than that of OA (72.9 %, p<0.001). For ICSI-spermatozoa cycles, there were no significant differences in CPR (22.6%, 29.4% and 26.1%) and LBR (16.1%, 29.4% and 19.6%) among NOA subgroups. The CPR of ICSI-spermatid cycles was 0.0%, 9.1% and 0.0% without a live birth. For ICSI-spermatocyte cycles, no clinical pregnancies occurred in any group. Conclusion: There was no significant difference in the FR of embryo-transferred TESE/ICSI cycles among NOA subgroups. The FR among all NOA subgroups was significantly lower than that of OA. Testicular histopathology in NOA did not affect successful pregnancy if spermatozoa extraction from the testis is successful and embryo transfer is possible.

• Clinical and Experimental Pediatrics
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• v.46 no.4
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• pp.393-396
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• 2003

Ileal atresia, a subtype of intestinal atresia, is one of the well-recognized causes of bowel obstruction in newborns. Prenatal diagnosis of intestinal atresia is very important in its management and outcome. Unfortunately, there are few cases of ileal atresia diagnosed prenatally, so more appropriate diagnoses and management plans are needed. As an associated gastrointestinal malformation with ileal atresia, hypertrophic pyloric stenosis is rarely reported. We report one case of postnatally diagnosed ileal atresia associated with hypertrophic pyloric stenosis which was complicated initially by bowel perforation and later by vomiting due to pyloric obstruction. Vomiting in the postoperative period is a common problem. But, if vomiting continues after the operation for ileal atresia, hypertrophic pyloric stenosis should be considered as a possible cause of medically retractable non-bilious vomiting.

• Journal of Yeungnam Medical Science
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• v.4 no.1
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• pp.33-42
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• 1987

Congenital origin intestinal obstruction are important disease due to required emergency operation. So accurate and rapid diagnosis is needed for decreased mortality and morbidity. Radiologist must detect to accurate obstruction site and also associated other congenital anomalies. And also embriological bases are very important role to the diagnosis of theses diseases. We were analysed radiologically and clinically 25 cases with congenital origin intestinal obstruction with review of literature. 1. Hypertrophic pyloric stenosis 6 cases, midgut malrotation 4 cases, congenital megacolon 8 case, imperforated anus 5 cases, ileal atresia 1 case and duodenal atresia 1 case. 2. Male and female radio were 16:9. Especially on hypertrophic pyloric stenosis, 5 cases were male infants. 3. All cases of hypertrophic pyloric stenosis represented string sign and also pyloric beak sign shoulder sign on UGI. 4. I case duodenal atresia showed double bubble sign on simple abdomen x-ray and ileal atresia showed mechanical small bowel obstruction sign with microcolon. 5. On midgut malrotation, cecum was located in right upper abdomen on 4 cases. And 2 cases were associated with Ladd's band. I case with volvulus and 1 case with mesenteric defect. 6. Involved site of all congenital megacolon were localized to rectosigmoid colon. 7. On 5 cases imperforated anus, 3 cases were low type and 2 case high type. Rectoperineal and rectourogenital fistula were demonstrated on 4 cases.