• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.70-83
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• 1997

We made a selection of engine operating conditions in the natural aspiration type diesel engine as load and speed. The effects on the power, smoke emission and cylinder pressure characteristics of these variations in operating conditions were observed experimentally. Also, the smoke emission was predicted by using the Arrhenius equation and empirical equation of the smoke emission was made. At the same time, the correlations, between the combustion and smoke emission characteristic were examined. From the above results, it is clear that to prevent power dropping and to decrease exhaust fume whin the conditions are changed, one should improve the intake system. To do this, the best way is to lower the air-fuel mixing ratio. We found that the parameters of the indicated mean effective pressure, maximum pressure and its location and combustion duration, etc. change the motion in accordance with the conditions described above. Also, we found that the variation of the pressure cycle comes from an amplified variation of the early part of process. From the analysis of comparing combustion and exhaust fume, the exhaust fume is produced at the latter time of combustion and decreased when the combustion ratio is higher. Also, we developed a special formula which can predict the exhaust fume value according to the engine load and speed.

• Journal of Chest Surgery
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• v.28 no.12
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• pp.1132-1138
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• 1995

From 1991 to 1994, we experienced 24 cases of neonatal pneumothorax who were admitted to the Neonatal Intensive Care Unit[NICU , Chosun University Hospital. The Following results were obtained.1 The incidence of neonatal pneumothorax was 0.70%, and there were 8 spontaneous pneumothoraces and 16 secondary pneumothoraces. 2 The clinical manifestation of neonatal pneumothorax was as followed. Male infant was dominant[M:F=2:1 , the onset was within 24 hours in the majority[83% , and the right side[62% was more frequent than the left side. The gestation duration and birth weight show no correlation with underlying neonatal pneumothorax. The pulmonary diseases were meconium aspiration syndrome and hyaline membrane disease, and the incidence of those was 58%. Meconium aspiration syndrome occurred earlier than hyaline membrane disease. Symptoms and signs were tachypnea[46% , cyanosis[21% , irritability[13% , chest retraction[8% and apnea[8% .3 The treatments performed were oxygen therapy[17% , thoracentesis[4% and closed thoracostomy with underwater seal drainage[79% . The Mean duration of air leakage was 11.7 hours, and the mean drainage time was 4.35$\pm$1.3day. 4 The overall hospital mortality was 33%, and the rate of complication was 46%. The complications were metabolic acidosis, atelectasis, pleural effusion, pulmonary hemorrhage and pneumonia. We concluded that the prognosis was related to the underlying pulmonary disease.

• Journal of Chest Surgery
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• v.18 no.4
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• pp.835-839
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• 1985

Spontaneous pneumothorax is the sudden collapse of a lung usually caused by air leaking from a sub-visceral pleural bleb. Response to closed thoracotomy, needle aspiration and simple observation is usually prompt and effective. But in some cases, these are unsuccessful and open thoracotomy is indicated. Author reviewed 37 cases of open thoracotomy in spontaneous pneumothorax experienced in the Dept. of Thoracic and Cardiovascular Surgery, Pusan National University Hospital, since Jan., 1980 to Dec., 1984. The results were as follows: 1. The causes of spontaneous pneumothorax: 73.0% was primary, 27.0% was secondary origin. 2. The most frequent age group of the patient: Between 11 and 30 years old. 3. All of te patient were male. 4. The side of open thoracotomy: 58.8% was right side, 8.8% was both side. 5. The most common indication of open thoracotomy; Persistent air leakage. 6. The most frequent sites of bleb or bullae: A-P segment in the L.U.L. and apical segment in the R.U.L.

• Phonetics and Speech Sciences
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• v.4 no.2
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• pp.95-104
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• 2012

Thyroidectomy patients may have vocal paralysis or paresis, resulting in a breathy voice. The aim of this study was to investigate the aerodynamic and acoustic characteristics of a breathy voice in thyroidectomy patients. Thirty-five subjects who have vocal paralysis after thyroidectomy participated in this study. According to perceptual judgements by three speech pathologists and one phonetic scholar, subjects were divided into two groups: breathy voice group (n = 21) and non-breathy voice group (n = 14). Aerodynamic analysis was conducted by three tasks (Voicing Efficiency, Maximum Sustained Phonation, Vital Capacity) and acoustic analysis was measured during Maximum Sustained Phonation task. The breathy voice group had significantly higher subglottal pressure and more pathological voice characteristics than the non breathy voice group. Showing 94.1% classification accuracy in result logistic regression of aerodynamic analysis, the predictor parameters for breathiness were maximum sound pressure level, sound pressure level range, phonation time of Maximum Sustained Phonation task and Pitch range, peak air pressure, and mean peak air pressure of Voicing Efficiency task. Classification accuracy of acoustic logistic regression was 88.6%, and five frequency perturbation parameters were shown as predictors. Vocal paralysis creates air turbulence at the glottis. It fluctuates frequency-related parameters and increases aspiration in high frequency areas. These changes determine perceptual breathiness.

• Journal of Chest Surgery
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• v.32 no.1
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• pp.38-42
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• 1999

Background: In neonatal respiratory distress syndrome patients, various types of pulmonary air leak contributes to elevate morbity and mortality. Although early surgical interventions can provide better results in several cases, whole clinical outcomes are poor. This study was designed to investigate the clinical aspects of pulmonary air leak in the neonatal respiratory distress syndrome patients and major contributing factors to mortality. Material and Method : We retrospectively evaluated 48 cases of pulmonary air leak in the neonatal respiratory distress syndrome patients from September 1994 to May 1997. Result: There were 15 cases of primary and 33 cases of secondary pulmonary air leakages. The prominent manifestations were pure interstitial emphysema in 19 cases(39.9%) and combined pneumothorax in 19 cases(39.9%). In clinical aspects, normal birth weight was dominant(83.4%), the onset occurred within 24 hours was in 28 cases(58.8%). The pulmonary diseases were meconium aspiration syndrome(25.2%) and hyaline membrane disease(33.2%). The overall hospital mortality was 25.2%, and the majority were hyaline membrane diseases. Conclusion: Although the overral mortality rate of these diseases were high, more detailed studies about immediate treatement, perinatal prevention, intensive care to geriatric problems were needed individually to improve outcomes.

• The Korean Journal of Air & Space Law and Policy
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• v.4
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• pp.139-154
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• 1992

The Chicago-Bermuda system has been charaterizing international aviation order sine 1940's. Bilateralism was established as 'the' way of nogotiation in exchange of traffic rights among nations thanks to the system. The system was stable until new phenomena came into the scene. The orderly development of international aviation began to be threatened by a series of technological and commercial breakthroughs in the late 60's and 70's. Also, in the field of international aviation, aspiration of the newemerging third world countries was hightened and the emergence of an unified Europe was added to it. These caused worries on bilateralism as an efficient means of negotiation. New waves of multilateral(reginal or international) approaches have been conducted. Its formal discussion is accelerated by vigorous talk on multilateral liberalization of international trade in commodities and services, i.e., the Urguay Round. In this paper, we examine historical development of bilateralism and multilateralism in a perspective of political economy; changes in the international aviation industry, merits and demerits of the two regimes on competitiveness of negotiating partners. The ways Korea can respond to new changes are presented and compared and a tentative stance she can take is proposed.

• Clinical and Experimental Pediatrics
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• v.50 no.8
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• pp.785-788
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• 2007

Epidural emphysema and pneumoscrotum with subcutaneous emphysema are rare in a child past the neonatal period. Their most common causes are bronchial asthma and respiratory infection. Here, we report an 18-month-old boy who was presented with severe air leak, consisting of epidural emphysema, pneumoscrotum, subcutaneous emphysema, and pneumomediastinum, complicated by a bronchial foreign body. The air leak was resolved dramatically after removing the foreign body.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.27 no.1
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• pp.40-44
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• 2016

Background and Objectives : Surgery is considered the primary treatment for intracordal cyst. However, patients who had undergone surgery are still subject to recurrence and continued voice changes. Intracordal cysts naturally disappear in some patient population. Cyst does not always recur in patients who had received partial surgical removal, too. Contradicting results raises a question whether complete surgical removal of intracordal cyst is necessary and demonstrate need for better treatment. Herein, the author proposes novel surgical method technique intralaryngeal needle technique (INT), a technique using surgical needle for not only injection but also for aspiration and excision of cyst. This study aims to examine the potential of intralaryngeal needle technique in treating intracordal cysts. Materials and Methods : Surgical procedures were done on in-patients diagnosed with intracordal cyst. 23 patients received follow-up screening after the surgery for one year. Patients' subjective satisfaction levels, acoustic measures, aerodynamic measures, laryngeal stroboscopic results were compared before and after the treatment. Results : Overall patients were satisfied with novel surgical excision method. In terms of aerodynamic measures, maximum phonation time, mean air flow rate improved after the surgery. In terms of acoustic measures, Jitter, Shimmer, NHR, and voice pitch changes after the treatment showed statistically significant differences. Laryngeal stroboscopy results showed significant decreases in cyst sizes. Post-surgery patients had improved mucosal waves and amplitudes values. Conclusion : The results show the validity of intralaryngeal needle technique in reducing intracordal cyst size by excision, aspiration, and injection. The author believes this novel technique can be used as an alternative surgical method for intracordal cysts.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.85-91
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• 2017

The present study aimed to investigate the changes of acoustic parameters of the aspirated voice in stroke patients. The eighty-eight subjects diagnosed with cerebro-vascular accident were divided into 32 penetration/aspiration (P/A) and 56 Non-P/A groups according to the videofluroscopic swallowing study (VFSS) results, and 26 control subjects participated. All subjects preformed VFSS and vowel /a/ was recorded three times pre- and post VFSS. Since the variation in the acoustic parameters within a single phonation has been observed, we proposed a delta formula for the acoustic parameters which can reflect the temporal changes of the each parameter in an utterance. We measured from the voice data eight acoustic parameters: fundamental frequency (F0), standard deviation of F0 (F0_SD), Jitter, relative average perturbation (RAP), Shimmer, amplitude perturbation quotient (APQ), harmonic to noise ration (HNR), noise to harmonic ratio (NHR). Then we found parameters which show the meaningful biggest temporal change in an utterance using the suggested delta parameter. Among them, the deltas of shimmer and APQ were significantly different pre- and post VFSS. These deltas of the P/A and the control group were increased after VFSS, while those of the Non-P/A group was descended. The variation patterns of the P/A and the control group were similar but the change width of the P/A group was larger. The large variations in an aspirated phonation of the P/A group are thought to be caused by irregular changes in air resistance due to residual food on the vocal cords.

• Journal of Embryo Transfer
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• v.15 no.1
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• pp.1-8
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• 2000

The ultrasound-guided oocytes cllection (ovum pick-up ; OPU) has become a substitution for superovlation in cattle. The objective of this study was to examine the effect of OPU frequency on the in vitro production of embryos in Hanwoo cattle. Six cycling Hanwoo cows were distributed into two groups for either once or twice weekly OPU sessions. Oocytes were collected by ultrasound-guided follicle aspiration(SA600) using a 6.5HMz transducer and attached with 18 gauge needle, with vacuum pressure of 40 mmHg. The cumulus-oocyte complexes (COCs) collected from each donor were matured in TCM 199 supplemented with 10% fetal bovine serum at 5% CO2 in air at 38.5$^{\circ}C$ for 22h and in vitro matured oocytes were co-incubated with sperm(separated by Percoll gradient) for 6h. The zygotes were co-cultured on cumulus cell monolayer in 10ul droplets in the same culture medium and conditions used for IVM for 7 days. On Day 7 of culture, development to blastocysts was examined. Although the number of oocytes collected was variable depending on individuals, overall embryo production in the twice per week OPU sessions was better that in the once per week sessions(6~21 vs 2~7 blastocysts produced, respectively). Two cows(E, A) were good oocyte donors and embryo production was superior in cow C ; however, cow F was a poor donor as compared to the others. In conclusion, these results suggest that for embryo production, twice weekly OPU sessions were better than once per week for producing embryos in vitro from Hanwoo cattle.