• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.173-180
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• 2007

Oscillating wave amplitude in a bottom-mounted OWC chamber designed for wave energy converter is investigated by applying characteristic wave conditions in Korean coastal water. The effects of shape parameters of OWC chamber in a view of wave energy absorbing capability are analyzed. Both experimental and numerical approaches are adopted and their results are compared to optimize the shape parameters which can result in a maximum power production under given wave distribution. The experiment was carried out in a wave flume under 2-D assumption of OWC chamber. The numerical scheme employed a hybrid Green integral equation which adopts the Rankine Green function inside chamber to take account of fluctuating air pressure, while it uses the Kelvin Green function in outer domain. Air duct diameter, chamber width, and submerged depths of front skirt and back wall of chamber changes the magnitude and peak frequency of wave absorption significantly.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.999-1003
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• 1992

Because of low noise and small size with huge capacity, a centrifugal fan is widely used for ventilation, air-conditioner and so on, which are very near to human life. Because of the complexity of its vibration and noise generation mechanics, most of researches on them are based on experimental methods. This study is to characterize the centrifugal fan noise and vibration. It is considered that noise is composed of the structural vibration noise and the air flow induced aerodynamic noise. To decouple the structural vibration noise the centrifugal fan is masked with an adhesive tape, such that air blowing is prohibited thus only the structural vibration noise is extracted. The noise level and characteristics in the frequency domain are verified and compared with those of total mixed one. This study shows some significant results that the structural vibration noise has relatively narrow band power spectrum compared with the total mixed one and has a strong periodicity. The sound level is lowered about 5dB by the removal of air flow with the masked fan for an air-conditioner used in this study.

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.130-134
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• 2024

Refractory chylous ascites can cause significant nutritional and immunologic morbidity, but no clear treatment has been established. This article introduces a case of a 22-year-old female patient with an underlying lymphatic anomaly who presented with refractory chylous ascites after laparoscopic adnexectomy for ovarian teratoma which aggravated after thoracic duct embolization. Ascites (>3,000 mL/d) had to be drained via a percutaneous catheter to relieve abdominal distention and consequent dyspnea, leading to significant cachexia and weight loss. Two sessions of hybrid lymphovenous anastomosis (LVA) surgery with intraoperative mesenteric lymphangiography guidance were performed to decompress the lymphatics. The first LVA was done between inferior mesenteric vein and left para-aortic enlarged lymphatics in a side-to-side manner. The daily drainage of chylous ascites significantly decreased to 130 mL/day immediately following surgery but increased 6 days later. An additional LVA was performed between right ovarian vein and enlarged lymphatics in aortocaval area in side-to-side and end-to-side manner. The chylous ascites resolved subsequently without any complications, and the patient was discharged after 2 weeks. The patient regained weight without ascites recurrence after 22 months of follow-up. This case shares a successful experience of treating refractory chylous ascites with lymphatic anomaly through LVA, reversing the patient's life-threatening weight loss. LVA was applied with a multidisciplinary approach using intraoperative mesenteric lipiodol, and results showed the possibility of expanding its use to challenging problems in the intraperitoneal cavity.

• The Korean Journal of Physiology
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• v.8 no.2
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• pp.45-48
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• 1974

It was planned to investigate, in mice that received ACTH, the influence of Panax Ginseng upon DNA synthesis of submandibular gland by observing incorporation of $[^3H]$ thymidine into the tissue cells. Thirty male mice $(body\;weight:\;18{\sim}20\;g)$ were divided equally into the ginseng-ACTIH and the saline-ACTH groups. Each animal of the ginseng-ACTH and the saline-ACTH groups received every day (subcutaneously) 0.05 m1/10 g body weight of ginseng extract(4 mg of ginseng alcohol extract in 1 ml of saline) and the same amount of saline, respectively, for 5 days. On the 5th experimental day, all animals received 0.01 unit of ACTH intraperitoneally one hour after the last medication, and $1\;{\mu}Ci/g$ body weight of $[^3H]$ thymidine after one more hour. Five animals, at a time, of each group were sacrificed 1, 10, and 24 hr after $[^3H]$ thymidine administration, and the radioactivity of cells in their mandibular gland was measured autoradiographically in terms of the % number of radioactive cells in 1,000 cell counts (Radioactive Index, R.1.). Results obtained were as follows: 1. The radioactive indices obtained from submandibular gland of the saline-ACTH group 1, 10 and 24 hr after $[^3H]$ thymidine administration were $15.2{\pm}0.32,\;20.1{\pm}0.30,\;and\;24.5{\pm}0.52(mean{\pm}S.D.)$ in the mucous cells, $13.0{\pm}0.22,\;10.2{\pm}0.05,\;and\;7.5{\pm}0.42$ in the serous cells. and $10.5{\pm}0.40,\;13.6{\pm}0.32,\;and\;15.9{\pm}0.42$ in the duct cells, while the $mean{\pm}S.D.$ of the values obtained from the 3 cell types 1, 10 and 24 hr after $[^3H]$ thymidine were $10.9{\pm}0.28,\;12.4{\pm}0.31,\;and\;10.0{\pm}0.39.$ Thus the radioactive indices obtained from the ginseng-ACTH group were generally lower than those obtained from the saline-ACTH group. It is inferred from the above results that the ginseng tends to promote the suppressive action of ACTH upon DNA synthesis of cells in the mandibular gland.

• Advances in pediatric surgery
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• v.2 no.2
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• pp.119-128
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• 1996

The survey on branchial anomalies was conducted by Korean Association of Pediatric Surgeons. A total of 173 cases were reported, which were managed by 36 members and cooperators during the three years from January 1, 1993 through December 31, 1995. The following results were obtained by retrospective analysis of the 173 cases of branchial anomalies. The presenting symptoms were cervical mass in 101 cases, pit with or without discharge in 71, cervical abscess in 47 and respiratory difficulty in 3. The average age of the patients with cervical abscess was 52 months. Seventy(79%) of 89 patients with branchial anomalies and a cystic mass had their first clinical manifestations by 1 year of age, while 40(51%) of 78 patients with only a branchial cyst had their first clinical manifestation in first year of life. Radiologic studies were carried out in 77 patients (43%). The preferred diagnostic modalities were ultrasonography(47 patients), simple neck radiogram(19) and CT scan(17). Preoperative diagnosis was correctly made in 156(91%) of 173 patients. Seventeen patients were incorrectly diagnosed as thyroglossal duct cyst in 5 patients, cystic hygroma in 4, dermoid cyst in 3, and lymphadenopathy in 3. There were no remarkable difference in sex and laterality of presentation but bilateral lesions were found in 9(5%) patients and unusual locations of the anomalies were the manubrium, left subclavicular area, median cervial area, preauricular and parotid area. There were 78(45%) patients with cyst, 52(30%) patients with sinus, 35(20%) patients with fistula and 8(5%) patient with skin tag. Embryological classification was possible in only 64(37%) patients. The 2nd branchial anomaly was present in 50(78%), the 1st branchial anomaly in 10(18%), and the 3rd or 4th branchial anomaly in 4(6%). Histopathological study of the lining epithelium(N=134) is recorded that 45% were lined with squamous epithelium, 17% with respiratory epithelium, 6% with. squamous and respiratory epithelium, 14% with inflammatory change. Lymphoid tissue was common(62%) in the wall of the lesions. Twelve(7%) of 158 patients had postoperative complications including wound complication, recurrence and facial nerve palsy.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.91-99
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• 2014

The common-rail injectors are the most critical component of the CRDI diesel engines that dominantly affect engine performances through high pressure injection with exact control. Thus, from now on the advanced combustion technologies for common-rail diesel injection engine require high performance fuel injectors. Accordingly, the previous studies on the numerical and experimental analysis of the diesel injector have focused on a optimum geometry to induce proper injection rate. In this study, computational predictions of performance of the diesel injector have been performed to evaluate internal flow characteristics for various needle lift and the spray pattern at the nozzle exit. To our knowledge, three-dimensional computational fluid dynamics (CFD) model of the internal flow passage of an entire injector duct including injection and return routes has never been studied. In this study, major design parameters concerning internal routes in the injector are optimized by using a CFD analysis and Response Surface Method (RSM). The computational prediction of the internal flow characteristics of the common-rail diesel injector was carried out by using STAR-CCM+7.06 code. In this work, computations were carried out under the assumption that the internal flow passage is a steady-state condition at the maximum needle lift. The design parameters are optimized by using the L16 orthogonal array and polynomial regression, local-approximation characteristics of RSM. Meanwhile, the optimum values are confirmed to be valid in 95% confidence and 5% significance level through analysis of variance (ANOVA). In addition, optimal design and prototype design were confirmed by calculating the injection quantities, resulting in the improvement of the injection performance by more than 54%.

• Journal of Korean Society of Forest Science
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• v.40 no.1
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• pp.1-18
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• 1978

Three Pinus densiflora populations as shown in location map (Fig. 1) were studied in 1977. These succeed the population numbers 10, 11 and 12 after the preceeding populations. Following the previous study methods, 20 trees were chosen from each population and the morphological characteristics such as tree forms, branching habit, needle and wood properties were investigated. The results are summerized as follows; 1. The mean stand ages were ranged from 40 to 45. The growth performances of trees of population 10 and 11 was similar, but 12 seemed to be inferior more or less. 2. The ratios of clear bole length was 0.53 in population 12 as the highest but 0.43 for population 10 as the lowest. 3. The population 12 was considered to be a stand of the coarser branching habit having the crown index (The maximum crown diameter/the crown length) 1.65 though the mean branching angle indicates almost horizontal. 4. The differences were observed in the clear bole length ratios and crown-indices between populations as shown in Fig. 3 and 4. 5. No inter-population differences in serration density of needle was shown but significant inter and intra-population and individual differences (within population) in number of stomata rows and resin duct. 6. Population 12 shown 0.119 of resin duct index as the maximum. 7. The pattern of diameter growth, analyses based on the width of 10-year-ring segment unit (for example, the 1st segment denotes the width between pith center and 10th year ring and the 2nd one is from 11th to 20th year ring and so on.), was alike among populations as shown in Fig. 9. 8. No significant differences between population in mean summer wood percentages as well as in wood specific gravity was observed. The values of wood specific gravity were increased with the increase of ages in population 10 and 11 however vice versa in population 12. 9. The fiber length was increased with the increase of age but no differences between populations as shown in Fig. 12.

• Journal of Korean Society of Forest Science
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• v.44 no.1
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• pp.1-25
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• 1979

Six natural populations of Pinus densiflora S. et Z. as shown in the location map (Flg 1) were studied during 1978. The numerial pouplation codes, 13 to 18. The results of populations 1 to 12 were reported in previous papers. Following the study methods described before, 20 trees were sampled from each population and morpological characteristics such as stem forms, branching habit needle and wood properties investigated. The results are summerized as follows; 1. The mean stand ages were ranged from 36 to 97 of years. The growth performances of trees of population 14. 15 and 18 was similar, but 13, 16, and 17 seemed to be inferior more or less. 2. The ratios of clear bole length were 0.70 in population 18 as the highest but 0.28 for population 16 as the lowest. 3. The population 17 was considered to be a stand of the coarser branching habit having the crown index (The maximum crown diameter/the crown height) 158 though the branching angles were almost horizontal. 4. The differences were observed in the clear bole length ratios and crown-indices between population as shown In Fig. 3 and 4. 5. As to the serration density, number of stomata row and resin duct; the significant differences exist between individual trees within population and also between populations. 6. Population 18 shown resin duct index 0.119 as the maximum. 7. The patterns of diameter growth, based on the width of 10-year-ring segment unit(for example, the 1st segment denotes the with between pith center and 10th year ring and the 2nd one is from 11th to 20th ring and so on.), were alike among populations as shown in Fig 9. 8. Significant differences between population in mean summer wood percentage as well as in wood specific gravity was observed. The values of wood specific gravity were increased with the increase of ages in population 14, 18 however vice versa in population 13, 15, and 17. 9. The fiber length was mereased with the increased of age but no differences between populations as shown in Fig. 12.

• Journal of Animal Environmental Science
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• v.14 no.1
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• pp.31-38
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• 2008

Ammonia gas is one of the malodorous gases from swine production facilities, such as manure storage tank, manure fermentation facilities, and livestock houses, etc. Ammonia gas from swine house is being emitted at relatively low concentrations throughout the year. Therefore, livestock facilities were continuously ventilated to supply fresh air for respiration of the animals internal the livestock facilities. The swine facilities need very high ventilation rate to control the inside environmental conditions. The deodorization system of the livestock facilities must be developed considering the ventilation rates. The odor abatement system was installed in order to improve the internal environment of the naturally ventilated growing-finishing pig house. The system which distributes the deodorized air into inner space of the swine house by using plastic duct was installed. Since the internal environment, effected by the operation of the odor abatement system, is monitored by closing the winch curtain installed on the side wall of the pig house, the experiment was practiced at the season when the internal environment becomes aggravated, winter. The effects on the improvement in the internal environment of swine house by operating the odor abatement system are as follows ; 1. By re-distributing the air which was deodorized by the odor abatement system installed in the pig house, the result showed that the concentration of ammonia gas is decreased approximately 33.3% compared with that before operating odor abatement system. 2. The effect on the pig house's ammonia gas reduction was found that the ventilation rate was less than $0.5m^3$/min head. The effect of the operation of the odor abatement system showed to be scarce when the ventilation rate increases because of the influx of external fresh air makes the quantity of diluted air more than those of the odor abatement system. 3. The perishment rate of the pigs which were brooded until slaughtering decreased about 3.8% by operating the odor abatement system in the growing-finishing pig house. Also, after operating the odor abatement system, the stinging of the eyes, suspension dust, etc were decreased when going into swine house for management.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.1061-1066
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• 2003

The present study was performed to investigate the effect of ozonation of the swine nursery building on indoor air quality and growth efficiency of the weanling piglets. Forty 21-day-old, cross-bred weanling piglets were housed in two ozonated or unozonated pens(10 males and 10 females per pen) for 3 wk alternately in a swine nursery building and this procedure was repeated three times. Ozone was generated using a commercial apparatus outside the nursery building and infused into the nursery building through a duct at a level of 0.03 ppm. Indoor concentrations of harmful gases were measured at 2-h intervals for a 24-h period per each 3-wk feeding trial. Indoor ammonia and carbon dioxide gas concentrations were reduced by the ozonation(P〈0.01) by 21% and 7%, respectively, compared with those of the control(unozonation), although hydrogen sulfide concentration was not affected by the treatment. However, the weight gain, feed intake and feed/gain of the piglets did not change due to the ozonation. Results suggest that ozonation of the swine nursery building is effective for improving the indoor air quality without affecting the production efficiency of weanling piglets.