• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.3
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• pp.68-80
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• 1984

This study was attempted in order to investigate the effects of superplasticizers on fresh and hardened concrete. The experimental program included tests on the slump and slump loss, bleeding, time of set, air content, the compacting, factor Vee Dee, compressive strength, tensile and flexural strength, permeability, shrinkage and freege-thaw durability. The major conclusions that can be drawn on the study are as follows. 1. Superplasticizers were observed to have an appreciable fluidifying action in fresh concrete so that tinder appropriate conditions, they either considerably improved its workability or permitted a water reduction of at least 8-12% to be made while maintaining normal workability. 2. The bleeding ratios of base and S,P. Concrete were much lower than those of the conventional concrete. Differences between the base and S.P. Concrete were insignifician. 3. The setting time was the longest for conventionla concrete, followed by S.P. concrete and base concrete in thatorder. And AE water reduction admixtures showed an appreciable influence on the setting and hardening characteristics of concrete and prolonged the stiffening times. 4. The high initial slump values of S.P. concrete generally decreased rapidly with increased standing time. CF values showed increasing tendencies with the increase of S.P. content, and excessive addition of S.P. caused the segregation of fresh concrete, resulting in its rejection. 5. Though there was a slight increase in strength, no significant differences are observed between base and S.P. concrete in terms of the compressive, tensile and flexural strength. 6. The permeability of S.P. concrete was significantly less than that of the conventional concrete, and the shrinkage of S.P. concrete was considerably smaller than that of the conventional concrete, but there were no significant differences between base and S.P. concrete. 7. Compared to base concrete, S.P. concrete without entrained air tended to slightly increase freeze-thaw durability, and S.P. concrete with an appropriate entrained air gave satisfactory resistance to freezing and thawing.

• Journal of Chest Surgery
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• v.26 no.5
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• pp.390-394
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• 1993

This study elvaluated clinically the surgical results of the thirty-eight patients who had exploratory thoracotomy for spontaneous pneumothorax between Jan. 1989 and Nov. 1992. Thirty three, or 86.8%, of the patients were male. The most frequent age of the spontaneous pneumothorax requiring thoracotomy was between fifteen years and twenty years. Sudden onset dyspnea and chest pain, which developed in thirty-five patients[89.5%], were the major chief complaints. Bleb and Bulla located in the both upper lobes were the most frequent causes of spontaneous pneumothorax for exploratory thoracotomy. There was no operative death. Postoperative morbidity included three cases of residual air space in the apical pleural space, tow cases of atrial fibrillation, and one each case of reoperation for bleeding, mediasitinitis, and sternal osteomyelitis. All postoperative complications were treated without any serious problems. This study suggests that early exploratory thoracotmy is desirable for patients with prolonged air-leak, massive air-leak, or multiple blebs and giant bullae on the computed tomography of the chest.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.291-300
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• 1999

Currently under development is an airborne auxiliary power unit with 100 Kw equivalent power, which is composed of a centrifugal compressor, a reverse annular combustor, and a radial turbine. Air-foil bearings are used in this power unit to eliminate the oil supplying system, which can reduce the system complexity and weight. The high speed generator is adopted as an electric power generation and engine starting system, which can also eliminate the reduction gear system. Not only electric power but also pneumatic power is provided by bleeding the compressed air This power unit is aimed for the multi-purpose use such as a primary power unit In the army weapon system, an auxiliary power and environmental control unit in a next-generation tank, and a smoke generating unit.

• Journal of Chest Surgery
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• v.33 no.4
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• pp.310-315
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• 2000

Background: A retrospectiye study was done for understanding morbidity and mortality after major lung resection. Material and Method: From June 1994 to August 1998, 203 patients received major lung resections for various causes. There were 142 males and 62 females with a mean age of 47.5 years. Initial complains were cough in 47.8%, sputum in 33.0%, hemoptysis or blood-tinged sputum in 23.2%, dyspnea in 18.2%, chest pain in 15.3%, weight loss in 10.8%, fever and chill in 4.9%. There were no complaints in 5.9% of the total patients. The underlying diseases were lung tumor(102 cases/50.2%), bronchectasis(28 cases/13.8%), aspergillosis(24 cases/1.8%), tuberculosis(20 cases/9.9%) and others (29 cases/66.5%) and pneumonectomy(68 cases/33.5%). The postoperative complications were classified as : empyema, BPF, respiratory problem, persistent air leakage over 7 days, arrhythmia, ventilator applied over 24 hours, bleeding, wound infection and chylothorax. The postlobectomy complications were revealed as follow: empyema(3.7%), BPF(2.2%), respiratory problem(5.2%), persistent air leakage over 7days(8.9%), arrhythmia(2.2%), ventilator applied over 24 hours(2.2%), bleeding(1.5%), wound infection(2.9%), chylothorax(0.7%). The postpneumonectomy complications were revealed as follow : empyema(5.9%), BPF (5.9%), respiratory problem(17.6%), persistent air leakage over 7days(0%), arrhythmia(5.4%), ventialtor apply over 24 hours(7.4%), bleeding (7.4%), wound infection(2.9%) and chylothorax(1.5%). Reoperation was done in 8 cases (4.0%). There were 5.8% operative mortalities in pneumonectomy and 0.7% in lobectomy.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.489-494
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• 2002

The basic Physical properties, Slump, Slump Flow, Air content, Bleeding, and Settlement of concrete was investigated to test Characteristic of Setting and to evaluate the relation between Model Specimen and Heat of Hydration for construction under Low Temperature (CFT). The objective of this study is to take the partial core after the cementation of Model Specimen, test the compression intensity and analyze the relation to Test Piece.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.121-126
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• 1983

8 cases of the esophageal perforations were treated at the department of thoracic surgery, Chungnam National University Hospital during the period from July, 1980 to Dec., 1982. The causes of the perforation were various; swallowed a piece of glass, stocking pin, coiled wire, compressed air blow, strenuous vomiting, dog bite, tiller accident, and endoscopic procedure. The perforation sites were cervical esophagus in 3 cases, upper thoracic in 2 cases and lower thoracic in remains. We have performed following surgical procedure; Incision and drainage for cervical abscess, closed thoracostomy, thoracotomy and debridement, esophagoscopy and gastrostomy. Two cases were died. The causes of death were massive bleeding and sepsis.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.638-644
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• 1999

Workability time of superplasticized concrete is maintained generally for 30-60 minutes only. Therefore it is of great advantage for the concrete producer to use a high range water reducer which provides an extended slump life. Recently slump retentive srperplasticizer has been developed. Concrete mixing tests were done to know slump, setting, air content, bleeding and hardening characteristics of concrete using slump retentive superplasticizer. With slump retentive superplasticizer, high quality concrete was produced and slump loss of concrete was reduced in big way, making long transportation time possible as a practical alternative to on-site addition.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.561-564
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• 2003

One of the most important reasons that CFT is used in many conditions is by using that we can achieve the effect, which reduce the section of the member. This research purpose to find the most ideal composition, which is achieved by the investigation in the concrete's property of matter like ability of Slump, Slump Flow, Air content, Bleeding, and Settlement when the high strength of concrete which is over 80㎫ is used in the CFT column.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1029-1034
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• 2003

The basic Physical properties, Slump, Slump Flow, Air content, Bleeding, and Settlement of concrete was investigateed to test Characteristic of Setting and to evaluate the relation between Model Specimen and Heat of hydration for construction Over the High Temperature (CFT). The objective of this study is to take the partial core after the cementation of Model Specimen, test the compression intensity and analyze the relation to Test Piece.

• 연구논문집
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• s.30
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• pp.5-13
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• 2000

The computation scheme of simulating gas turbine transient behavior was developed. The basic principles of this scheme and main input data required are described. Calculation results are presented in terms of whole operating regime of the cycle. The influence of main initial parameters such as starting engine power, moment of inertia of the rotor, fuel supplying schedule etc. on performance characteristics of has turbine during transient operation is studied In addition, bleeding air influence on transient behavior was also considered For validation of the developed code, comparison of present calculation with that of measurement data of the experimental data for the range of operating period studied.