• 한국군사과학기술학회지
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• 제12권3호
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• pp.396-405
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• 2009

The experimental research was conducted to setup a performance prediction logic for the regenerative cooling system on a small scale liquid rocket engine using kerosene and LOX. Total heat flux of the combustion gas side was determined for the flow rate of the coolant, combustion pressure using the calorimeter thrust chamber. Based on the experimental investigation, a performance prediction scheme for the regenerative cooling system is setup in our own way. A performance prediction logic for the regenerative cooling system has been developed by the correction scheme of the combustion gas side. The key parameters determining the temperature limitation of the coolant are the mass flow rate of the coolant and the length of the combustion chamber and the nozzle. And the parameters to control the limitation of the usable wall temperature are the number of channels and wall thickness.

• Archives of Plastic Surgery
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• 제33권4호
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• pp.399-406
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• 2006

Purpose: The authors accessed the anthropometric measurements of fourty non-cleft normal a three-month-old infant and using this obtained data as a basic guideline, authors applied the modified Noordhoff technique for the treatment of bilateral cleft lip. Methods: Over a period of 10 years, a total of 21 bilateral cleft lips were operated. 13 cases of complete and 8 cases of incomplete bilateral cleft lip and palate. In the complete type of bilateral cleft palate, elastic head cap and passive intraoral appliance were applied at 1 to 2 week of age for 2 months duration. The definitive cheiloplasty was performed at 3 months of age using the modified Noordhoff technique. Results: After a follow-up period ranging one to nine years, most patients presented with cosmetically and functionally satisfying results, with an exception of two cases where an undesired peaking effect of the vermilion and dimpling of the vermilion mucosa was encountered. Conclusion: Accessing the anthropometric measurements of fourty non-cleft normal three-month-old infant and using this obtained dara as a guideline, the modified Noordhoff technique can be applied to either complete or incomplete bilaterally cleft lip providing more naturally pleasing and cosmetically satisfying scars that lie in harmony with the philtral ridges, lip tubercle positioned just below the vermilion and a distinct white line and Cupid's bow.

• 한국정밀공학회지
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• 제19권7호
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• pp.97-105
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• 2002

The use of rapid prototyping (RP) has reduced time to market, cut total costs and improved product quality by giving design and manufacturing teams the opportunity to verify and fine tune designs before committing them to expensive tooling and fabrication. In order to improve their unique characteristics according to the working principles, Variable Lamination Manufacturing process (VLM-ST) and corresponding CAD/CAM software (VLM-Slicer) is developed. The objective of this study is to improve the accuracy of VLM-ST process, and it can be done by offset fur cutting error correction, cutting path overrun fur sharp edge and reference shape generation for off-line stacking. It has been shown that, through the verification experiments for given practical shapes, the proposed algorithms are effective for diverse categories of three-dimensional shapes.

• Journal of Chest Surgery
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• 제27권4호
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• pp.259-265
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• 1994

Cor triatriatum is a relatively rare cardiac anomaly, whose major feature is a fenestrated membrane separating an upper common pulmonary venous chamber from a lower true left atrial cavity. Interatrial communications may be present between the right atrium and the common pulmonary venous chamber or the true left atrium. From April 1981 to April 1992, 24 patients with cor triatriatum were treated at Seoul National University Hospital. Ages ranged from 1 month to 24 years with mean of 7.4 years. Twenty patients had interatrial communications through a patent foramen ovale, primum or secundum defect of the atrial septum. Four had no interatrial communications. Fourteen patients had associated anomalies; partial anomalous pulmonary venous connection in 3, total anomalous pulmonary venous connection in 2, persistent left superior vena cava in 3, and other anomalies in 6 patients. Surgical corrections were performed through right atriotomy in 18 patients, left atriotomy in 4, and both atriotomy in 2. Three patients [12.5%] died early after operation; two of them were associated with single ventricle. Six out of 21 survivors [28.6%] experienced complications; recurrent pneumonia, pulmonary embolism, ischemic encephalopathy, diaphragmatic palsy and tachyarrhythmias. At the time of follow up, all survivors, except one, were in functional class I. Surgical correction of cor triatriatum restored normal hemodynamic status with relatively low operative mortality, especially in patients not complicated with severe anomalies. This report summarizes the clinical diagnosis, associated anomalies, interatrial communications, surgical approach and late result of 24 patients underwent surgical corrections in our hospital.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6211-6217
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• 2014

Previous genome-wide association studies (GWAS) have implicated several single nucleotide polymorphisms (SNPs) in the AT-rich interactive domain 5B (ARID5B) gene with childhood acute lymphoblastic leukemia (ALL). However, replicated studies reported some inconsistent results in different populations. Using meta-analysis, we here aimed to clarify the nature of the genetic risks contributed by the two polymorphisms (rs10994982, rs7089424) for developing childhood ALL. Through searches of PubMed, EMBASE, and manually searching relevant references, a total of 14 articles with 16 independent studies were included. Odds ratios (ORs) with 95% confidence intervals (95%CI) were calculated to assess the associations. Both SNPs rs10994982 and rs7089424 showed significant associations with childhood ALL risk in all genetic models after Bonferroni correction. Furthermore, subtype analyses of B-lineage ALL provided strong evidence that SNP rs10994982 is highly associated with the risk of developing B-hyperdiploid ALL. These results indicate that SNPs rs10994982 and rs7089424 are indeed significantly associated with increased risk of childhood ALL.

• Journal of Power Electronics
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• 제13권4호
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• pp.592-599
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• 2013

This paper investigates a new isolated single-phase AC-DC converter, which integrates a modified AC-DC buck-boost converter with a DC-DC forward converter. The front semi-stage is operated in discontinuous conduction mode (DCM) to achieve an almost unity power factor and a low total harmonic distortion of the input current. The rear semi-stage is used for step-down voltage conversion and electrical isolation. The front semi-stage uses a coupled inductor with the same winding-turn in the primary and secondary sides, which is charged in series during the switch-on period and is discharged in parallel during the switch-off period. The discharging time can be shortened. In other words, the duty ratio can be extended. This semi-stage can be operated in a larger duty-ratio range than the conventional AC-DC buck-boost converter for DCM operation. Therefore, the proposed converter is suitable for universal input voltage (90~264 $V_{rms}$) and a wide output-power range. Moreover, the voltage stress on the DC-link capacitor is low. Finally, a prototype circuit is implemented to verify the performance of the proposed converter.

• 환경영향평가
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• 제20권5호
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• pp.765-777
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• 2011

According to the total pollution load management system, exact prediction and analysis of water quality and discharge has been required in order to allocate the amount of pollution load to each local government. In this study, QUAL2E model was used for comparison with other water quality models and improve the inadequate to forecast future water quality. And Various calibration and verification methods were applied to deal with existing uncertainties of parameter during modeling water quality. For user convenience, A GUI(Graphical User Interface) system named "QL2-XP" model is developed by object-oriented language for the user convenience and practical usage. Suggested GUI system consist of hydraulic analysis, water quality analysis, optimized model calibration processes, and postprocessing the simulation results. Therefore this model will be effectively utilized to manage practical and efficient water quality.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.285-286
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• 2006

The essential tasks to operate the welding robot are the acquisition of the position and/or shape of the parent metal. For the seam tracking or the robot automation, many kinds of contact and non-contact sensors are used. Recently, the vision sensor is most popular. In this paper, the development of the system which measures the profile of the welding part is described. The total system will be assembled into a compact module which can be attached to the head of welding robot system. This system uses the line-type structured laser diode and the vision sensor It implemented Direct Linear Transformation (DLT) for the camera calibration as well as radial distortion correction. The three dimensional shape of the parent metal is obtained after simple linear transformation and therefore, the system operates in real time. Some experiments are carried out to evaluate the performance of the developed system.

• Journal of Chest Surgery
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• 제19권4호
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• pp.627-632
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• 1986

This report describes our 17-years experience with intracardiac repair in 123 patients older than 15 years with tetralogy of Fallot. Major clinical manifestation was cyanosis and clubbing [102 Pts], but other minor associated manifestation were infective endocarditis, pulmonary tuberculosis, brain abscess, congestive heart failure, nephrotic syndrome, and tuberculous spondylitis. Prior palliative shunts had been performed in 10 patients. Preoperative hemoglobin ranged from 9.7 gm/dl to 25 gm/dl [mean 19 gm/dl]. The type of ventricular septal defect were typical perimembranous type, and total canal defect [13%]. The right ventricular outflow tract obstruction was due to combined [58.5%], infundibular [35%], and valvular stenosis [6.5%]. Transannular patch was used in 17% of patients. Hospital mortality was 9.8% in overall, but decreased to 1.7% since 1982. There was two late death [12 year actuarial survival [97%] due to fulminant hepatitis, residual abnormalities [PS, VSD]. Ninety two percent of survivors at follow-up are asymptomatic and leading an active normal life. Residual ventricular septal defect was detected with radionuclide single pass study in 15.3% of patients but almost cases were Qp/Qs less than 1.5, and only two patients had been candidates for reoperation.

• Journal of Chest Surgery
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• 제24권1호
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• pp.1-7
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• 1991

This report describes our 10-year experience with intracardiac repair in 42 patients older than 16 year with tetralogy of Fallot. The mean age was 22.0$\pm$5.18 years[range 16~41]. The preoperative clinical manifestations were cyanosis & clubbing[93%], frequent URI [55%], anoxic spell[40%], pulmonary tuberculosis[21%], tuberculous empyema[7%], chronic renal failure[7%], congestive heart failure[7%] and subacute bacterial endocarditis [2%], etc. The previous shunt procedure for palliation had been performed in 7 patients. The type of VSD were typical perimembranous type[67%], total canal defect[28%] and combined type[5%]. The right ventricular outflow tract obstruction were combined type[69%], infundibular type[21%] and valvular type[10%]. Transannular patch was used in 50% of patients. Associated cardiovascular anomalies were ASD[33%], PFO[31%], Rt. aortic arch[10%], Lt. SVC[10%], single Rt. pulmonary artery, single Lt. coronary artery, ASI, proximal stenosis of Rt. pulmonary artery and anomalous systemic venous return, etc. Hospital mortality was 7.1%[3 cases]in overall. The causes of hospital deaths were revealed low cardiac output & acute renal failure[2 cases], postoperative bleeding[1 case]. There were 2 late deaths 3 & 68 months after surgery. Residual intracardiac shunt was detected in 2 patients. one patient was successfully reoperated and another patient had Qp /Qs ratio less than 1.5.