• Journal of Chest Surgery
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• 제23권1호
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• pp.32-40
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• 1990

Surgical correction of congenital cardiac defects in infants and children with an elevated pulmonary arterial pressure or pulmonary vascular resistance carries a significant early postoperative mortality. And accurate assessments of cardiac output is critically important in these patients. From April 1988 through September 1989, serial measurements of cardiac index, ratio of pulmonary-systemic systolic pressure, ratio of pulmonary-systemic resistance, central venous pressure, left atrial pressure, and urine output during the first 48 hours after the cardiac operation were made in 30 congenital cardiac defects associated with pulmonary hypertension. Cardiac index showed significant increase only after 24 hour postoperatively and this low cardiac performance in the early postoperative period should be considered when postoperative management is being planned in the risky patients. There were no variables which showed any significant correlation with cardiac index. In 12 cases[40%], pulmonary hypertensive crisis developed during the 48 hours postoperatively, and they were treated with full sedation, hyperventilation with 100 % 0y and pulmonary vasodilator infusion. In all patient with preoperative pulmonary hypertension, surgical placement of a pulmonary artery catheter is desirable to allow prompt diagnosis of pulmonary hypertensive crisis and to monitor subsequent therapy.

• 한국해양공학회지
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• 제1권2호
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• pp.74-82
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• 1987

This study has been made to investigate into the behavior of fatigue limit, of fatigue crack initiation, and of fatigue crack propagation under the condition of rotating bending stress; specifically on the independency of stress field as well as the crack behavior of surface micro hole defect, which is made artificially through the specimen. The results obtained can be summarized as followa; 1) For the single micro hole defect, initiation of fatigue crack is occurred at both tips of microhole defect simultaneosly along the slip which are produced in the range of maximum principal stress arround micro hole defect independent of the size of micro hole defect. 2) For the neighbored deuble micro hole defects with equal size, in the range ($\frac{L}{r}$)ratio $\gtrsim$ 3 defined as the size of micro hole defect(2r) to the distance between the centers of micro hole defects (2L), the crack behavior of the micro hole defects is same as single one. However, for the range of $\frac{L}{r}$<3, the interference effect becomes significant as the ratio approaches to 1.

• Archives of Plastic Surgery
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• 제47권5호
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• pp.451-459
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• 2020

Background For volar soft tissue defects of the proximal interphalangeal (PIP) joint, free flaps are technically challenging, but have more esthetic and functional advantages than local or distant flaps. In this study, we compared the long-term surgical outcomes of arterial (hypothenar, thenar, or second toe plantar) and venous free flaps for volar defects of the PIP joint. Methods This was a single-center retrospective review of free flap coverage of volar defects between the distal interphalangeal and metacarpophalangeal joint from July 2010 to August 2019. Patients with severe crush injuries (degloving, tendon or bone defects, or comminuted/intra-articular fractures), thumb injuries, multiple-joint and finger injuries, dorsal soft tissue defects, and defects >6 cm in length were excluded from the study, as were those lost to follow-up within 6 months. Thirteen patients received arterial (hypothenar, thenar, or second toe plantar) free flaps and 12 received venous free flaps. Patients' age, follow-up period, PIP joint active range of motion (ROM), extension lag, grip-strength ratio of the injured to the uninjured hand, and Quick Disabilities of Arm, Shoulder & Hand (QuickDASH) score were compared between the groups. Results Arterial free flaps showed significantly higher PIP joint active ROM (P=0.043) and lower extension lag (P =0.035) than venous free flaps. The differences in flexion, grip strength, and QuickDASH scores were not statistically significant. Conclusions The surgical outcomes of arterial free flaps were superior to those of venous free flaps for volar defects of the PIP joint.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.852-862
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• 1996

This study was carried out to develop tools to detect defects of apple using machine vision. For the purpose, 6 kinds of frame for color images, R, G, B, h, S, and I frame, and a frame for near infra-red images (NIR frame) were tested first to select one which is useful to segment defect areas from apple images. After then, several methods to classify kind of defect for the segmented defect areas were developed and tested. Five kinds of apple defect -bruise , decay ,fleck worm hole and scar were investigated . The results are as follows: NIR frame was selected as the best one among the 7 kinds of image frame, and R, G and I frames showed favourable result to segment areas of apple defect. Various features of the segmented defect areas were measured to classify the defect areas. Eight kids of feature of the areas-size, roundness, axes length ratio, mean and variance of pixel values, variance of real part of spectrum, mean and variance of power spectrum resulted from spacial ourier transform were observed for the segmented defect areas in the selected 4 frames. then procedures to classify defects using the features were developed for the 4 frames and tested with 75-113 defects on apples. The test resulted that NIR and I frames showed high accuracies to classify the kind of defect as 77% and 76% , respectively.

• Steel and Composite Structures
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• 제29권5호
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• pp.647-657
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• 2018

Geometric imperfections may be created during the production process or setting borders of single-layer graphene sheets (SLGSs). Vacancy defects are an instance of geometric imperfection, so investigating the effect of these vacancies on the mechanical properties of single-layer graphene is extremely important. Since very few studies have been conducted on the structure of imperfect graphene (with the vacancy defect) as an anisotropic structure, further study of this defective structure seems imperative. Due to the vacancy defects and for the proper assessment of mechanical properties, the graphene structure should be considered anisotropic in certain states. The present study investigates the effects of site and size of vacancy defects on the mechanical properties of graphene as an anisotropic structure using the lekhnitskii interaction coefficients and Molecular Dynamic approach. The effect of temperature on the severity of the SLGS becoming anisotropic is also investigated in this study. The results reveal that the amount of temperature has a big effect on the severity of the structure getting anisotropic even for a graphene without any defects. The effect of aspect ratio, temperature and also size and site of vacancy defects on the material properties of the graphene are studied in this research work. According to the present study, using material properties of flawless graphene for imperfect structure can lead to inaccurate results.

• Advances in pediatric surgery
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• 제6권1호
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• pp.32-39
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• 2000

Evaluation of the sacrum in anorectal malformations (ARMs) is important because there is an association between sacral abnormalities and poor functional outcome after corrective surgery for ARM. Sacral defects are not easily detected because of immaturity of sacrum in children and defects are often overlooked by pediatric surgeons. The authors utilized the sacral ratio in normal children (N=61) and patients with ARMs (N=26). In normal children, the mean true sacral ratio and mean sacrococcygeal ratio were $0.60{\pm}0.08$ and $0.72{\pm}0.13$ respectively. The sacral ratio was not correlated with age and did not changed with age in the same patient. However, true sacral ratio and sacrococcygeal ratio were significantly lower in patients with high type ARMs than those of normal children (p<0.001). There was no difference between patients with low type ARMs and normal children. These results suggest that abnormal sacrums are more frequently encountered in patients with high type ARMs than in normal children, and that true sacral ratio and sacrococcygeal ratio can be used in the evaluation of the abnormal sacrum.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.79-83
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• 1992

According to the variation of hydrostatic pressure on the central axis of deformable material, the V-shaped central bursting defect may be created on extrusion or drawing processes. The process factors whichaffect the generation of defects are die semi-angle, reduction ratio of cross-sectional area, friction factor, material properties and so on. The combination of these factors can determine the prossibility of defect creation and the shape of various round holes which have been created inside already. By the rigid plastic finite element method, this paper describes the observations of change in shape of a round hole with process conditions suchas die semi-angle, reduction ratio of cross-sectional area and friction factorat the unsteady state of axi-symmetrical extrusion process when the round hole is alreadyexisted inside the original billet, and also, the effects of process factors are investigated to prevent the possible defects.

• Smart Structures and Systems
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• 제23권1호
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• pp.71-79
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• 2019

In general, it may be advantageous to measure the pressure pulsation near a valve to detect a valve defect in a linear compressor. However, the acceleration signals are more advantageous for rapid classification in a mass-production line. This paper deals with the performance improvement of fault classification using only the compressor-shell acceleration signal based on the relation between the refrigerant pressure pulsation and the shell acceleration of the compressor. A transfer function was estimated experimentally to take into account the signal noise ratio between the pressure pulsation of the refrigerant in the suction pipe and the shell acceleration. The shell acceleration signal of the compressor was modified using this transfer function to improve the defect classification performance. The defect classification of the modified signal was evaluated in the acceleration signal in the frequency domain using Fisher's discriminant ratio (FDR). The defect classification method was validated by experimental data. By using the method presented, the classification of valve defects can be performed rapidly and efficiently during mass production.

• Journal of Chest Surgery
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• 제11권1호
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• pp.46-57
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• 1978

Ventricular septal defect was the most common congenital Heart disease admitted to the Severance Hospital from December, 1963 to June 30. 1977. A total of 1,811 cardiac patients received cardiac catheterization in the CardiacCenter of Yonsei University Medical College. Out of the 1,811 cardiac patients, 791 cases had congenital heart disease and of these 172 cases had ventricular septal defect. This amounted to 21.7% of all those with congenital heart disease. Seventy cases of ventricular septal defect operated on in the chest surgery department are presented. Of these 70 cases of ventricular septal defect, 54 cases were male and 16 cases were female. Their ages ranged from 4/12 months to 32 years. The ratio of systolic pressure of the main pulmonary to systemic artery [Pp/Ps] for 29 of the 59 isolated ventricular septal defects was below 45 percent. Pp/Ps ratio for 19 of the 59 isolated ventricular septal defects was 75 percent. The patients were mostly below fifteen years of age. Out of 64 cases, there were 36 cases of type II defects, 20 cases of type I, 4 cases of type III , 2 cases of type IV, one case of both type II and one case of left ventricular right atrial communication. The anomalies associated with ventricular septal defect were 13 in all; 4 cases of aortic insufficiency, 3 cases of ruptured aneurysm of the sortie sinus of valsalva, 2 cases of ruptured aneurysm of the sortie sinus of valsalva with aortic insufficiency, 2 cases of patent ductus arteriosus, one case of ruptured aneurysm of the aortic sinus of valsalva with atrial septal defect [secundum type] and one case of atrial septal defect [secundum type]. Overall mortality was 8.6 percent. The mortality in pulmonary artery banding was 37.5 percent. The causes of mortality were in one case congestive heart failure, in one case asphyxia and in one case respiratory insufficiency. Tile mortality in ventricular septal defect associated with pulmonary hypertension was 7.1 percent. The cause of mortality was in one case low cardiac output syndrome. There was no mortality in the ventricular septal defects without pulmonary hypertension and mortality in the ventricular septal defect. In ventricular septal defect associated with combined anomalies, the causes mortality were in one case respiratory insufficiency and in one case congestive heart failure.

• 한국레이저가공학회지
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• 제6권3호
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• pp.19-28
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• 2003

The manufacturing process for the microfluidic device can include sequential steps such as master fabrication, electroforming, and injection molding. The laser ablation, using masks, has been applied to the fabrication of channels in microfluidic devices. In this research, an excimer laser was used to engrave microscopic channels on the surface of PET (polyethylene terephthalate), which shows a high absorption ratio for an excimer laser beam with a wavelength of 248 m. When 50-${\mu}{\textrm}{m}$-wide rectangular microscopic channels are ablated with a 500 ${\times}$ 500 ${\mu}{\textrm}{m}$ square mask at a magnification ratio of 1/10, ditch-shaped defects were found in both corners. The measurement of laser beam intensity showed that a coherent image in the PET target caused such defects. Analysis based on the Fourier diffraction theory enabled the prediction of the coherent shape at the image surface as well as the diffraction beam shape between the mask and the image surface. It also showed that the diameter of the aperture had a dominant effect. The application of aperture with a diameter of less than 3 mm helped to eliminate such defects in the ablated rectangular microscopic channels on PET without such ditch-shaped defects.