• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.213-215
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• 2012

As one of the primary fuel sources, oxy-fuel combustion of coal is actively being investigated because of the climate changing problem such like the emission of green house gases. In this paper research about the pulverized coal technology, which is widely used in both power-generating and iron-making processes was studied to invesgate the ignition behaviour of pulverized coal particles during coal combustion as changing the ambient oxygen concentration of the particle. The ignition phenomenon of the coal particles fed into a laminar flow reactor was imaged with a Integrated charged-coupled device (ICCD) camera. The ignition points were determined throught the analysis of the images, and then the ignition delay times were able to be calculated. The experiment results show that a lower oxygen concentration increases the ignition delay time.

• Journal for History of Mathematics
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• v.31 no.3
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• pp.127-150
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• 2018

In spite of important researches and translational works of the Joseon mathematical treatises in the 80's and on, these results were almost out of reach to the school teachers as well as students due to the antiquity of their contents and the terms used. In order to make our traditional mathematics approachable to the middle and high school students, it will be educationally meaningful to reinterpret them tuned at the student's level using modern terminology and symbols. In this study, we reinterpreted 9 problems from Cheukryang Dohae, which is one of the representative mathematical books of Joseon Dynasty. We used the terminology and symbols from the school curriculum. We also reconstructed two of them using modern metrologies adapted to modern situations adding illustrations and photos, so that they are useful at the teaching site.

• Journal of Chest Surgery
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• v.15 no.4
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• pp.381-386
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• 1982

Pulmonary artery aneurysm usually carries an ominous prognosis due to the associated pulmonary hypertension. In July 1981, a patient with a huge aneurysm of main pulmonary artery secondary to pulmonary hypertension and bacterial endocarditis due to a patent ductus arteriosus was treated by resection of the aneurysm and Dacron patch graft replacement and closure of the patent ductus arteriosus. The immediate postoperative result was excellent. We now report the surgical treatment, clinical course, and one and half years follow up of the patient.

• Journal of Chest Surgery
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• v.19 no.3
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• pp.500-505
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• 1986

Eight patients received operation for ascending aortic aneurysm and aortic regurgitation associated with Marfan`s syndrome from January 1984 to July 1986 at Seoul National University Hospital. The patients` age ranged from 29 to 51 years [mean 37.3 years]. Five patients were male and three were female. All of them showed some stigmata of skeletal system in Marfan`s syndrome. Three patients had dissecting aneurysm and five patients had fusiform aneurysm of ascending aorta. Two patients had concomitant fusiform aneurysm of abdominal aorta. All patients showed aortic regurgitation of grade III to IV. One patient received insertion of intraluminal ringed graft and resuspension of aortic valve, and seven patients received modified Bentall operation [Carol`s method]. There was no hospital death and all showed functional improvement in the 7.4 patient-years follow-up period.

• Annual Conference of KIPS
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• 2014.11a
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• pp.306-309
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• 2014

네이티브 어플리케이션의 한계를 극복하기 위해 웹 서비스를 이용한 Hybrid Application이 개발되었다. Hybrid Application은 단말기의 센서, 카메라 등 기기의 기능을 Application이 지원하고 내부 구조와 인터페이스, 데이터 전송 등에 Web기술을 이용하여 기존 네이티브 어플리케이션의 단점을 보완하고 장점을 합한 것이다. 웹 기반으로 구현 되었기 때문에 다양한 기기와 해상도에 적용이 가능하고 문제 발생 시 웹과 동일하게 실시간 업데이트가 가능하다. 본 논문에서는 HTML5과 하이브리드 어플리케이션 기반의 SNS 메신저를 설계하고 구현하였다. SNS의 게시판 기능과 메신저를 결합하여 커뮤니케이션을 강조한 어플리케이션을 구현하여, one-source-multi-platform SNS 시스템을 구축하였다.

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.963-968
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• 2001

New anthracycline analogues 2-9 as potential anticancer agents have been synthesized from daunomycin (1a) and doxorubicin (1b). Compounds 2 and 6 were prepared by the nucleophilic displacement type esterification of 14-bromodaunomycin (1c) with N-benzoyl-(2R,3S)-phenylisoserine and L-pyroglutamic acid in triethyl-amine, respectively. Compounds 3, 7 and 4, 8 were prepared by the reaction of either daunomycin (1a) or doxorubicin (1b) with one equivalent of the corresponding acids in the presence of EDCI/PP. Compounds 5, 9 were obtained from 1b by reaction with 2.2 equivalents of the corresponding acids in the same manner. The cytotoxic activities of the analogues in comparison with adrimycin on cultured SNU-16 and MCF7 cell were described.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.587-592
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• 2001

The potential anticancer agents new anthracycline derivatives (2~9) have been synthesized from daunomycin (1a) and doxorubicin (1b) ad starting materials. Compounds 2 and 6 were prepared by the nucleophilic displacement type esterification of a 14-bromodaunomycin (1c) with a acetylsalicylic and palmitic acid in triethylamine, respectively. Compound 3 and 7 were obtained from daunomycin (1a) by direct amidation with the corresponding acids in the presence of EDCI and PP as esterification regents. Whereas 4 and 8 were prepared by reaction of doxorubicin (1b) with one equivalent of acetylsalicylic and palmitic acid using DCC/DMAP, respectively, 5 and 9 were obtained from 1b by acylation with two equivalents of the corresponding acids using EDCI/PP reagents.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.97-101
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• 1983

The steadily increasing number of operations performed on the heart has given rise to occasional complications involving the nervous system, and this has been interested to cardiac surgeons and neurologists. This survey has been carried out on all Gases submitted to open heart surgery at Seoul National University Hospital during 1982 to determine which operative features were associated with the occurrence of neurological damage. 514 subjects were studied and neurological damage was noted in twenty-five patients [4.9%]. Eight of these 25 patients died in the postoperative period, but neurological damage contributed to the fatal outcome in six cases. Remaining seventeen patients were discharged without problems except one Cortical blindness and one hemiplegic patients who were survived without other problems . A number of features were found to be related to the development of neurological damage, which were age, duration of perfusion, nature of operation, cardiac rhythm and presence of the thrombi or calcification and hypothermic arrest. But many unknown etiological factors are remained out of our sight. A significant increase in the incidence of neurological damage was shown in older age group [13.3% in over 40 year of age], and also the duration of the bypass was associated with subsequent neurological injury especially more than 120 minutes [11.6%]. The presence of atrial fibrillation with intracardiac thrombi or calcification was also a contributing factor to developing neurological complication [16.7%]. These factors were regarded to influence the postoperative neurological complications and more effective method for prevention of these neurologic complication should be studied.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.666-671
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• 1984

During a fire-year period from March 1979 to February 1984, 559 patients underwent surgical treatment for rheumatic mitral valve disease at Seoul National University Hospital. Left atrial thrombus was found at surgery in 74 of these patients, an incidence of 13.2%. This report outlines the surgical experience with these seventy-four patients. They were 32 men and 42 women, and their age ranged between 23 and 57 with mean of 42 years old. All except one had the findings of atrial fibrillation on the preoperative electrocardiogram. Ten [13.5%] had experienced embolic events before surgery. A history of one or more episodes of cardiac failure requiring digitalis and diuretics was noted in all patients Nineteen were associated with the aortic and/or tricuspid valve disease and closed mitral commissurotomy had been performed previously in four patients. The average cardiac index was 2.68L/min/M2 [1.59 to 3.47 L/min/M2] The mean systolic pulmonary artery pressure was 57mmHg [26 to 120 mmHg]and pulmonary capillary wedge pressure 21.5 mmHg [12 to 40 mmHg]. There were no significant hemodynamic findings to suggest the presence of the left atrial thrombus. Operative mortality was acceptable with two early deaths [2.7%]. The follow-up of the hospital survivors has shown excellent functional status.

• Journal of Chest Surgery
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• v.23 no.6
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• pp.1146-1151
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• 1990

Supravavular aortic stenosis is a congenital narrowing of the ascending aorta just distal to the level of the origins of the coronary arteries, that may be localized or diffuse. Five patients with supravalvular aortic stenosis were operated upon between July, 1986 arid June, 1990. Four of these patients were William`s syndrome [mental retardation, elfin face], and one was isolated supravalvular aortic stenosis. Preoperative diagnosis of the supravalvular aortic stenosis was made by left side cardiac catheterization and angiocardiography. There are three types of supravalvular aortic stenosis such as membranous, hourglass and hypoplastic. Four of our patients were of hourglass type, and one was hypoplastic type. Patch aortoplasty was performed in all cases. Preoperative systolic gradients ranged from 45 to 1SO mmHg [average 102.6 mmHg]: postoperative gradients ranged from 0 to 75 mmHg [average 39 mmHg]. The patient of hypoplastic type has been suffered from mild exercise intolerance even after the operation, and the postoperative echocardiography revealed the systolic gradient of 100 mmHg [preoperative 180 mmHg]. The results of surgery for hourglass type were excellent. But the patient with hypoplastic form would be benefited from some modifications of the operation.