• Journal of Chest Surgery
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• v.31 no.1
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• pp.46-51
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• 1998

Treatment of esophageal perforation when diagnosed late remains controversial. Ten consecutive patients since 1990 were treated late(later than 24 hours) for esophageal perforation with primary repair. Four perforations were iatrogenic, 3 were spontaneous, 2 were foreign body aspiraton and 1 was trauma. The interval from perforation to operation was 116 hours in mean and 48 hours in median value. The principles of repair included (1) a local esophagomyotomy proximal and distal to the tear to expose the mucosal defect and intact mucosa beyond, (2) debridement of the mucosal defect and closure, (3) reapproximation of the muscle, and (4) adequate drainage. The repair was buttressed with parietal pleura or pericardial fat in 9 patients. Associated distal obstruction was treated with dilation and esophagomyotomy intraoperatively. There was one mortality and cause of death was massive gastric bleeding due to gastric ulcer on 33rd day after operation. Five patients had leak at the site of repair and these cases were treated completely with conservative treatment except a mortality case. In conclusion, in the absence of malignant or irreversible distal obstruction, meticulous repair of perforated esophagus and adequate drainage are preferred approach, regardless of the duration from the injury to the operation.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.16-20
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• 2010

본 연구는 지하 냉동 창고 화재발생시 천공이 화재진압의 방법으로써 화재성상에 미치는 영향 등 천공의 효과를 검증하고 화재진압 기술에 대한 기초연구로서 천공의 위치, 천공 개방 시간, 천공 개방에 따른 근접 건축물로의 화재 전파양상을 FDS를 통하여 시뮬레이션 하여 분석하였다. 천공의 개방은 내부 화재의 요인을 빨리 소모시켜 온도 및 발열량을 빠르게 낮춘다. 이와 같이 천공의 유무에 따라 화재에 양상이 바뀌기 때문에 화재 진행 사항 및 화재 장소 가연물에 형태 등 각 화재 형태에 따라 적절한 천공의 위치 및 개방시간등이 마련되어야 할 것이다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.3 no.2
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• pp.56-62
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• 1989

자연채광에 관한 에너지 해석을 하기 위해서는 주광조도를 예측하여야 하며, 주광조도를 예측하기 위해서는 천공상태를 추정할 수 있어야만 한다. 즉, 천공상태의 최저상태나 최소설계기준을 추정할 수 있어야만 자연채광에 의한 에너지 절약을 해석할 수가 있다. 천공상태를 추정하는데에는 CIE에서 개발한 정적 천공모델이 많이 이용되어 왔다. 그러나 천공은 정적광원이 아니라 시간에 따라 동적으로 변하고 있음으로 자연채광설계에서 에너지의 영향을 평가하기 위해서는 보다 융통성이 있는 천공모델이 요구된다. 따라서 이 논문은 그동안 동적천공을 나타낼 수 있도록 개발된 비표준천공의 추정방법, 동적 천공상태의 추정방법, 주광조도와 천공휘도의 추정방법, 주광의 유용성 평가방법 등을 비교분석함으로써, 앞으로 우리나라 기후상태에 적합한 자연채광용 천공모델을 개발하는데 기초자료화하였다.

• Tunnel and Underground Space
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• v.4 no.2
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• pp.87-91
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• 1994

팽창재와 같은 비촉성 파쇄재는 화약발파와 비교하여 볼 때 진동을 유발하지 않는다는 면에서 인접한 구조물에 영향을 주지 않고 암반을 파괴할 수 있는 장점을 갖고 있다. 비폭성 파괴방법으로 유압식 암석분할기도 팽창재와 유사한 적용성을 갖고 있으나 힘을 작용시킬수 있는 천공깊이에 제약을 갖고 있으며 규모가 큰 암반의 파괴 방법으로는 적용한계가 있다. 반면에 팽창재는 천공깊이에 큰 제약을 받지 않으며 천공수에 제한을 받지 않는다는 장점이 있다. 그러나 팽창재의 현장적용시 가장 큰 단점의 하나로 지적되고 있는 것은 파괴력을 나타내기까지의 시간이 오래 걸림으로 작업능률에 문제가 있다는 것이다. 반응시간은 물과 팽창재와의 반응률과 밀접한 관계를 갖고 있으며 본 논문에서는 팽창재의 적용성을 높이기 위하여 실시한 여러 조건하에서 팽창재 반응률 특성에 관한 연구내용을 기술한다. 연구결과를 요약하면 다음과 같다. 1)팽창재의 반응은 주위온도에 큰 영향을 받는다. 2) 팽창재의 성능을 충분히 발휘하기 위하여는 주위 온도 조건에 따라 천공직경을 적절히 조절하는 것이 필요하다. 3) 낮은 주위 온도 조건에서 팽창재의 반응은 압력이 증가하는 시간이 느리고 따라서 최대 팽창압이 높은 온도 조건에 비해서 낮게 나타난다. 4)팽창압이 증가하는 시간은 팽창재와 물과의 반응률에 좌우된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.42-42
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• 2010

전기천공(electroporation)은 세포에 nanosecond-millisecond 정도의 폭을 가지는 전기 펄스를 0.4-1.5 kV/cm 의 세기로 인가하여 세포 막 표면에 나노미터 크기의 미세한 기공을 형성하는 기술로서, 1970년대 처음 발견된 이래 수십 년 동안 다양한 생명공학 분야에 적용되어 왔다. 적절한 전기 펄스 조건 하에서 생성된 세포 막 표면의 미세 기공은 일정 시간 후 다시 사라지는 가역적 특성을 가져 이를 가역적 전기천공(reversible electroporation)이라 부르며, 주로 친수성약물, 유전자, 효소, 항체 등의 물질을 세포 내로 주입시키는 데 사용한다. 반면 이보다 강한 전기 펄스 하에 생성된 미세 기공은 사라지지 않고 결국 세포의 생명력을 잃게 하는 기전으로 작용하며, 이를 비가역 전기천공(irreversible electroporation)이라 한다. 비가역 전기천공 기술은 가역적 전기천공 측면에서는 바람직하지 않은 현상으로 인식되기도 하였으나, 최근 들어 그 장점을 이용한 기술적 접근이 이루어지고 있다. 전기천공은 주로 식품산업에서 미생물을 죽이는 기술이나 세포의 체외(in vitro) 유전자 주입 기술에 응용되어 왔으나, 현재는 암을 치료하기 위한 의학적 기술로 큰 주목을 받으며 많은 연구들이 진행되고 있고, 일부 기술은 이미 상용화 단계에 와있다. 본 발표는 전기천공의 기술적 이론적 배경과 함께 다양한 의학적 응용 기술에 대한 정보를 제공하며, 국내외 기초 및 응용 연구 동향 파악을 통해 국내 저변 확대 및 추후 발전 전망에 대해 논의 할 것이다.

• Journal of Chest Surgery
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• v.39 no.3 s.260
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• pp.214-219
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• 2006

Background: Perforation of esophagus is relatively uncommon. but it is associated with high morbidity and mortality. Treatment and outcome are largely determined by the time of presentation. We performed a retrospective review of patients with esophageal perforation to assess the outcome of current management techniques. Material and Method: A retrospective chart review was performed on all patients treated for perforation of esophagus from March 1990 to March 2005. There were 28 patients (22 men and 6 women: mean age 51 years, range 17 to 82 years) The causes of the perforations were as follows: foreign body retention (9 patients), trauma (7 patients), spontaneous rupture (7 patients), and iatrogenic (5 pati-ients). 18 patients were presented within 24 hours and 10 patients were presented after 24 hours., Esophageal repair was performed in 21 ($75\%$) of them, 4 patients were treated with esophagectomy, 3 patients were treated with feeding gastrostomy and drainage. Result: Hospital mortality was $18\%$ and iatrogenic was increase the mortality rate (p < 0.05). Site of perforation, time from perforation, and treatment method had no influence on mortality. Postoprative leaks occurred in 4 patients after primary repair and were treated conservatively. Conclusion: Esophageal perforation remains a devastating event which is difficult to diagnose and manage. Primary repair can be performed in most patients with esophageal perforation regardless of time to presentation with a low mortality. Accurate diagnosis and early treatment are essential to the successful management of patients.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.4
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• pp.561-571
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• 2019

Drilling and charging of the blast holes during NATM tunneling works take more than 30% of construction time among the whole tunneling work process. Prediction of ground condition ahead of tunnel face has been studied by several researchers by correlating percussion pressure and drilling speed during tunneling work with the ground condition and/or RMR values. However, most of the previous researches were conducted in the granite rock condition which is the most representative igneous rock in the Korean peninsula. In this study, drilling speeds in igneous rocks were analyzed and compared with those in sedimentary rocks (most dominantly composed of conglomerates, sandstones, and shales) under the similar RMR ranges; it was identified that the drilling speed is pretty much affected by rock types even in a similar RMR range. Under the similar RMR values, the drilling speed was faster in sedimentary rocks compared with that in igneous rock. Moreover, while the drilling speed was not much affected by change of the RMR values in igneous rocks, it became faster in sedimentary rocks as the RMR values got lower.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.147-152
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• 2020

The research is carried out to analyze the cost-effectiveness of blasting patterns with regard to the diameters and design of blasting holes. Blasting patterns for single diameter array, and mixed diameter array were comparatively analyzed with regard to drilling and charging time, and materials required. The number of blasting holes required for single array pattern and mixed array pattern were 138 and 93 holes, respectively. From the drilling time analysis, reduction in time and its efficiency of mixed pattern were 139 minutes and 25%, respectively, in comparison with single pattern. Charging time reduction and its efficiency of mixed blasting pattern were evaluated as 22.5 minutes per worker and 33%, respectively, compare to single blasting pattern. The explosive quantities of G1 and G2 required for single array patterns were 270 and 30, while those were 222 and 20 for mixed array patterns for tunnelling 4m. And single pattern required 45 more detonators than the mixed pattern. The evaluation of material required can also be positive parameter for cost reduction of tunnel construction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.26-35
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• 2020

Tunnel construction is an important part of Korean public construction projects. Although the development of various equipment and technologies has led to advances in tunnel construction methods that are implemented on sites, the cost standards related to such works do not yet reflect the realities of the construction sites. A literature review and site surveys were conducted to suggest reasonable cost standards for tunnel work that reflects the realities of the field. First, each item in the cost standards for tunnel work, as established in the Construction Standard Production Rates, were analyzed. The results were compared with the actual costs implemented on tunnel projects. The key items analyzed included those regarding the work cycle time, such as rock classification, profiling survey, drilling speed, and muck-disposal processing equipment combination, as well as the number of people put to tunneling work. Based on the site survey results, improved estimates regarding the cycle time per one tunnel drilling blast, drilling speed of the machine, muck disposal processing equipment combination, and the number of people put to tunneling work were suggested. This study suggests the cost standards that reflect the realities of tunneling sites. The results are expected to help ensure adequate costs for tunnel construction projects.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.19-27
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• 2010

Sky cover method can be used to determine sky condition by cloud amount of the Korea Meteorological Administration. And, HCI (Hourly Clearness Index) method is another method determined by measured horizontal global radiation data. The results of the HCI methods of Erbs et al. (1982), Orgill and Hollands (1977) seem to be not good enough because of the air pollution such as smog phenomenon or yellow sand phenomenon and so on. Therefore, HCI should be corrected. The aim of this study is to improve HCI. Therefore, this study is to analyze and compare on the sky conditions from Sky cover method and HCI, and then presents hourly correction factor based on Sky 채팩 method. The results of corrected HCI improved.