• 한국화재소방학회논문지
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• 제28권5호
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• pp.37-43
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• 2014

재실자가 부속실로의 피난 시 부속실 송풍기가 작동하기 전단계에서는 실내화재로 인한 풍속이 발생하여 부속실 개방과 더불어 연소생성물이 부속실을 오염시켜 피난장애의 결과를 가져올 수 있다. 이로인한 화재크기 및 실내 개구부 크기가 화재풍속에 미치는 영향을 확인하기 수치해석 연구를 수행하였다. 수치해석에서는 화재크기 및 실내 개구부 크기를 달리하였고, 실제의 공동주택 형상과 치수를 반영하였다. 수치해석 결과, 화재크기별 실내의 개구부 크기에 따라서 중성대 높이가 변화하여 부속실로 흐르는 화재풍속 특성이 다르게 나타남을 확인할 후 있었다. 또한, 실내 중성대가 높은 곳에 형성된 경우에는 방화문 상 하부에서 화재풍속의 차이가 나타남을 확인할 수 있었다.

• Journal of Chest Surgery
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• 제26권6호
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• pp.475-482
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• 1993

90 patients[75 men and 15 women] with the thoracic disease underwent video-assisted thoracic surgery[VATS] during the period March 1992 to February 1993. The thoracic diseases were classified into two groups of spontaneous pneumothorax and general thoracic patients and they were 66 and 24, respectively.The mean size of the tumor resected was 4.3 $\pm$ 2.0 cm x 3.3 $\pm$ 1.1 cm x 2.7 $\pm$ 1.0 cm. The mean time of anesthesia and operation were 90.0 $\pm$ 19.9 min and 43.7 $\pm$ 13.1 min in spontaneous pneumothorax group and 123.3 $\pm$ 40.3 min and 62.8 $\pm$ 32.2 min in general thoracic group. The mean period of postoperative chest tube drainage and hospital stay were 5.0$\pm$ 5.5 days and 6.6 $\pm$ 7.4 days in spontaneous pneumothorax group and 3.5$\pm$ 1.6 days and 9.5 $\pm$ 6.1 days in general thoracic group. The indications of VATS were 71 pleural disease[78.9%: 66 spontaneous pneumothorax; 3 pleural effusions ; 1 pleural paragonimus westermanii cyst; 1 malignant pleural tumor with metastasis to the lung], 9 mediastinal disease[10.0%: 5 benign neurogenic tumor; 2 pericardial cyst; 1 benign cystic teratoma; 1 undifferentiated carcinoma], 8 pulmonary parenchymal disease[8.9%: 3 infectious disease ; 3 interstitial disease ; 2 malignant tumor ], and 2 traumatic cases of exploration and removal of hematoma[2.2%]. The applicated objectives of VATS were diagnostic[ 7 ], therapeutic[ 67 ] and both[ 16 ] and the performed procedures were pleurodesis[ 66 ], wedge resection of lung[ 59 ], parietal pleurectomy[ 11 ], removal of benign tumor[ 9 ], excision and/or biopsy of tumor[ 4 ], pleural biopsy and aspiration of pleural fluid[ 3 ] and exploration of hemothorax and removal of hematoma in traumatic 2 patients. The complication rate was 24.2%[ 16/66 ] in the spontaneous pneumothorax group and 8.3%[ 2/24 ] in the general thoracic group and so overally 20.0%[ 18/90 ]. The mortality within postoperative 30 days was 2.2%[ 2/90 ], including 1 acute renal failure and 1 respiratory failure due to rapid progression of pneumonia. The conversion rate to open thoracotomy during VATS was 5.6%[ 5/90 ], including 2 immediate postoperative massive air leakage, 1 giant bullae, 1 malignant pleural tumor with metastasis to lung and 1 pulmonary malignancy. The successful cure rate of VATS was 75.8%[ 50/66 ] in the spontaneous pneumothorax group and 76.5%[ 13/17 ] in the general thoracic group and the successful diagnostic rate was 100%[ 7/7 ]. In conclusion, although prospective trials should be progressed to define the precise role of VATS, the VATS carries a low morbidity and mortality and high diagnostic and therapeutic success rate and now can be effectively applicated to the surgical treatment of the extensive thoracic disease.

• 한국전자파학회논문지
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• 제26권4호
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• pp.381-388
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• 2015

본 논문에서는 TV 유휴대역에서 가능한 응용서비스중 하나로서, UHF 대역(470~806 MHz)에서 동작하는 무선 영상전송 시스템을 구현하였다. 이 시스템은 RF 송수신기 모듈, 디지털 모뎀, 카메라, 스크린으로 구성된다. RF 송수신기와 디지털 모뎀을 연동하여 VGA급 화질의 카메라 영상을 2.6 인치 LCD 스크린에 표시하는 방식이다. RF 송수신기 구조는 크기와 비용을 줄이기 위해 직접변환 방식을 채택하였다. 성능지표인 Image Leakage를 향상시키기 위하여 PLL의 출력에 3차 하모닉 제거필터를 사용하였으며, DC offset 문제 해결을 위해 DAC 출력노드에 Current steering technique을 이용하여 공통모드 전압을 조절하게 하였다. 또한, 채널대역폭은 국가별 표준을 맞게 6, 7, 8 MHz 중 선택이 가능하다. 출력 파워와 수신감도는 각각 +10 dBm, -82 dBm이다. 디지털모뎀은 Kintex-7급 FPGA에서 구현하였다. QPSK와 512ch OFDM 변조를 기반으로 전송속도는 약 9 Mbps이다. 개발된 송수신 모듈을 이용하여 VGA급 화질을 무선으로 송수신하는데 성공하였다.

• Journal of Chest Surgery
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• 제49권2호
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• pp.80-84
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• 2016

Background: Video-assisted thoracoscopic surgery (VATS) pulmonary wedge resection has emerged as the standard treatment for primary spontaneous pneumothorax. Recently, single-port VATS has been introduced and is now widely performed. This study aimed to evaluate the outcomes of the Tower crane technique as novel technique using a 15-mm trocar and anchoring suture in primary spontaneous pneumothorax. Methods: Patients who underwent single-port VATS wedge resection in Chungnam National University Hospital from April 2012 to March 2014 were enrolled. The medical records of the enrolled patients were reviewed retrospectively. Results: A total of 1,251 patients were diagnosed with pneumothorax during this period, 270 of whom underwent VATS wedge resection. Fifty-two of those operations were single-port VATS wedge resections for primary spontaneous pneumothorax performed by a single surgeon. The median age of the patients was $19.3{\pm}11.5$ years old, and 43 of the patients were male. The median duration of chest tube drainage following the operation was $2.3{\pm}1.3days$, and mean post-operative hospital stay was $3.2{\pm}1.3days$. Prolonged air leakage for more than three days following the operation was observed in one patient. The mean duration of follow-up was $18.7{\pm}6.1months$, with a recurrence rate of 3.8%. Conclusion: The tower crane technique with a 15-mm trocar may be a promising treatment modality for patients presenting with primary spontaneous pneumothorax.

• 말소리와 음성과학
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• 제4권1호
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• pp.125-131
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• 2012

The patients with incomplete glottic closure have an important feature decreasing the maximum phonation time (MPT) because airflow rate or air leakage is greater than people without voice disorders. Also they can appear a problem in the intensity regulation. This study analyzed MPT difference based on the comfortable intensity and louder intensity and the correlation between MPT and respiration volume of unilateral vocal fold palsy (UVFP) and sulcus vocalis (SV) group. The twenty with UVFP, the 21 with SV, the 21 normal subjects measured MPT in /a/ vowel prolongation task with comfortable intensity and louder intensity and compared analysis by measuring FVC, $FEV_1$, $FEV_1/FVC$ to analyze the correlation between MPT and respiration volume. First, a comparison of MPT according to the intensity between groups is that MPT of the normal group was statistically significant long compared to the patient group in comfortable intensity, but MPT between groups was not statistically significant difference in the louder intensity. Second, an analysis of the correlation between MPT and respiration volume is that this was statistically significant correlation between MPT in comfortable intensity and MPT in louder intensity. But this did not show statistically significant correlation between intensity and respiration volume. This study can be supported the preceding study results deduced that shorting MPT of the patient group compared to the normal group was originated in the problem of laryngeal valving mechanism at the level of vocal folds rather than a problem of respiratory function. Also at the phonation by varying the intensity, the result can deduce that in the case of patient group, the length of MPT had been improved by increasing the glottal closure ratio in the louder intensity. These results can support the theoretical basis that should be applied to the clinicians by varying the intensity at the voice evaluation and voice therapy for the patients with the glottis incompetence.

• Journal of Chest Surgery
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• 제27권12호
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• pp.1015-1022
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• 1994

Over the past few years, video-assisted thoracic surgery [VATS] has been used increasingly for intrathoracic pathologic problems as a less invasive operative techniques. Today it is viewed as a sparing and safe alternative to thoracotomy for a wide spectrum of indications. Using video-assisted operative thoracoscopy, we performed consecutive 150 operations on 148 patients during the initial 2 years of our experience from July 1992 with the following indications: pneumothorax [n=53], hyperhidrosis [n=29], mediastinal mass [n=23], pleural disease [n=13], diffuse parenchymal or interstitial lung disease [n=12], benign pulmonary nodule [n=7], metastatic lung mass [n=3], primary lung cancer [n=3], bronchiectasis [n=2], malignant pericardial effusion [n=2], endobronchial tuberculosis [n=1], esophageal achalasia [n=1], and pulmonary parenchymal foreign body [n=1]. There were no death, and overall complicaton rate was 24.0%[n=36]. The most prevalent complication was persistent air leakage [longer than 5 days] in 14 cases [9.3%]. Persistent pleural effusion [longer than 5 days] occurred in 6 cases [4.0%]. Six patients were converted to an open thoracotomy because of inability to control the operative bleeding [n=3], failed adhesiolysis in bronchiectasis [n=2], and radical excision of an lung cancer [n=1]. Pneumothorax recurred in 3 cases[2.0%]. Other complications were Horner`s syndrome, diaphragm tears, temporary phrenic nerve palsy, hoarseness, subsegmental atelectasis, transient respiratory difficulty, and esophageal mucosal tear. The advantages of this minimally traumatizing operative technique lie in improved visualization, decreased pain, shortened hospital stay, and less postoperative morbidity. The indications of VATS has been extended increasingly to intrathoracic pathologies, but its role in the managements of primary lung cancer and esophageal disease remains to be defined.

• 에너지공학
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• 제27권4호
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• pp.70-79
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• 2018

한국중부발전 제주화력본부에서 방류되는 온배수로부터 열원을 회수하여 약 3 km의 원거리에 위치하고 있는 신촌백합영농조합법인의 시설온실에 냉온수를 공급하기 위한 300 RT 용량의 열펌프 시스템을 구축하였다. 원거리 시설로 온배수열을 공급하기 위한 최적화 방안을 도출하였고, 수송관로의 온도와 누수여부를 모니터링하기 위한 설비들이 설치되었다. 본 논문에서는 제주 시설온실 냉난방을 위한 발전소 온배수 활용 열펌프 시스템의 구성과 주요기기에 대해 기술하였다. 2018년 하절기에 열펌프 시스템의 냉방성능을 평가하기 위한 실증운전을 수행하였다. 냉방운전 시 열펌프 시스템의 주요 위치에서 측정된 유체의 온도와 유량, 그리고 냉방 성능계수를 분석하여, 구축된 열펌프 시스템의 안정성과 냉방성능을 검증하였다.

• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2004년도 총회및 심포지움
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• pp.67-72
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• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml $h^{-1}\;m^{-2}\;atm^{-1}$ at $5^{\circ}C\;and\;99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%\;CO_2+1\;or\;20\%\;O_2,\;8\%\;CO_2+1\;or\;20\%\;O_2,\;or\;12\%\;CO_2+20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2+1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SSC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown using black polyethylene mulch under NF was over 7-fold that of slices from tomato fruit grown using hairy vetch under Tom-Cast. When stored at $20^{\circ}C$, slices from light-red tomato fruit grown with black polyethylene or hairy vetch mulches both showed a rapid increase in electrolyte leakage beginning 6 hours after slicing. However, slices from tomato fruit grown using the hairy vetch mulch tended to have lower electrolyte leakage than those grown with black polyethylene mulch. These results suggest that tomato fruit from plants grown using hairy vetch mulch may be more suitable for fresh-cut slices than those grown using black polyethylene mulch. Also, use of the disease forecasting model Tom-Cast, which can result in lower fungicide application than is currently used commercially, resulted in high quality fruit for fresh-cut processing. Experiments were conducted to determine if ethylene influences chilling injury, as measured by percentage of slices exhibiting water-soaked areas in fresh-cut tomato slices of 'Mountain Pride' and 'Sunbeam' tomato (Lycopersicon esculentum Mill.). Ethylene concentration in containers without ventilation significantly increased during storage at $5^{\circ}C$, whereas little or no accumulation of ethylene occurred in containers with one or six perforations. Chilling injury was greatest for slices in containers with six perforations, compared to slices in containers with one perforation, and was over 13-fold greater than that of slices in control containers with no perforations. An experiment was also performed to investigate the effectiveness of including an ethylene absorbent pad in containers on subsequent ethylene accumulation and chilling injury. While ethylene in the no-pad controls increased continually during storage of both 'Mountain Pride' and 'Sunbeam' tomatoes at $5^{\circ}C$ under modified atmosphere conditions, no increase in accumulation of ethylene was observed in containers containing ethylene absorbent pads throughout storage. The ethylene absorbent pad treatment resulted in a significantly higher percentage of chilling injury compared with the no-pad control. In studies aimed at inhibiting ethylene production using AVG during storage of slices, the concentration of ethylene in control containers (no AVG) remained at elevated levels throughout storage, compared to containers with slices treated with AVG. Chilling injury in slices treated with AVG was 5-fold greater than that of controls. Further, we tested the effect of ethylene pretreatment of slices on subsequent slice shelf-life and quality. In slices treated with ethylene (0, 0.1, 1, or $10\;{mu}L\;L^{-1}$) immediately after slicing, ethylene production in non-treated controls was greater than that of all other ethylene pre-treatments. However, pretreatment of slices 3 days after slicing resulted in a different pattern of ethylene production during storage. Ihe rate of ethylene production by slices treated with 1 L $L^{-1}$ ethylene 3 days after slicing was greater during storage than any of the other ethylene treatments. With slices pre-treated with ethylene, both immediately and 3 days after slicing, the rate of ethylene production tended to show an negative correlation with chilling injury. Chemical name used: 1-aminoethoxyvinylglycine (AVG).

• Journal of Chest Surgery
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• 제36권12호
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• pp.904-910
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• 2003

흉강경을 이용한 자연기흉 수술은 개흉술에 비하여 재발률이 높지만 많은 외과의에게 선호되고 있다. 또한 이러한 단점을 극복하기 위한 여러 시도가 이루어지고 있다. 저자들은 흉강경수술 시 자동 봉합기의 봉합선 보강효과를 알아보기 위하여 동물실험과 임상연구를 계획하였다. 대상 및 방법: 동물실험에서는 실험견을 이용하여 바로 도살한 후 자동 봉합기를 적용한 폐(제1군, N=5)와 자동 봉합기를 사용하여 48시간 경과한 후 도살한 폐(제2군, N=5)의 절제면에서 최초 공기 누출압을 측정하였다. 또한 각각 제1군과 2군에서 봉합선을 보강재료로 보강여부에 따른 절제면의 공기 누출압을 비교하였다. 임상연구에서는 자연기흉 흉강경수술을 받은 104명(106건)을 대상으로 봉합선 보강 여부에 따라 임상 성적을 비교하였다. 결과: 동물실험에서는 자동 봉합기의 봉합선을 보강한 군에서 의의 있게 평균 공기 누출압이 높았고(제1군: 비보강군; 18$\pm$1.6, 보강군; 483, 제2군: 비보강군; 23.8$\pm$1.9, 보강군; 54$\pm$4.6 mmHg, p<0.001), 임상연구에서는 봉합선 보강군에서 술 후 흉관 유치기간, 술 후 재원기간, 사용한 총 자동 봉합기 길이 등에서 유의한 차이를 보였다(흉관 유치기간: 비보강군; 4.4$\pm$1.4, 보강군; 3.1$\pm$1.1일, 사용한 자동 봉합기의 총길이: 비보강군; 92.3$\pm$28.1, 보강군: 71.1$\pm$30.6 mm, 술 후 재원기간: 비보강군; 5.9$\pm$1.9, 보강군; 4.6$\pm$l7일, p<0.001). 결론: 자연기흉 흉강경 수술에서 자동 봉합기의 봉합선 보강으로 술 후 장기간 공기누출의 예방이 가능하였고, 따라서 술 후 병원재원 기간의 단축이 가능하였다.

• 생물환경조절학회지
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• 제14권3호
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• pp.218-231
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• 2005

본고에서는 우주에서 장기간에 걸쳐 임무를 수행하는 인간의 생명지원을 목적으로 CELSS를 이용한 식물생산, 물과 공기의 정화 및 재생, 폐기물 처리 등을 위한 공학적 접근을 검토하였다. 이러한 공학적 접근에는 미소중력 또는 저압과 같은 우주 환경에 적용 가능한 폐쇄형 식물생산 시스템, 물질 순환, 물의 재생, 폐기물의 처리, 미량 유해가스의 제거, 조명, 배양액의 공급 등이 포함된다. 우주에서 재배 가능한 작물의 선택 기준으로 높은 생산성, 식용성, 소화성, 조리성, 자동화 가능성, 짧은 줄기, 높은 증산속도 등이 제기되고 있다. 화성 표면에서의 낮은 압력은 작물 생산용 온실을 설계할 때 주요 장애물에 해당한다. 때문에 저압하에서 식물 재배가 가능한 팽창식 온실의 개발에 관심이 집중되고 있다. 팽창식 온실의 구조, 내부 압력, 자재, 조명 방식, 방사선 차폐 등은 주요 설계 인자에 해당한다. 팽창식 온실 내의 낮은 압력은 구조물의 질량과 가스의 누출속도를 줄일 수 있다. 저압 조건에서는 증산속도가 급격하게 증가하여 식물의 수분요구도가 높게 나타난다. 증산 또는 수경재배시스템으로부터의 증발에 의해서 수분이 대기 중으로 방출될 때 증기압이 증가한다. 저압 조건에 있는 폐쇄계에서는 증기압의 변화가 전체 압력에 커다란 영향을 미친다. 그러므로 저압 조건의 수경재배시스템은 누수로 인하여 기화되는 수분 손실을 줄이기 위해서 고도로 밀폐되어야 한다. 또한 저압으로 유지되는 온실내의 상대습도를 높게 유지할 수 있는 환경제어 기술이 개발되어야 한다. 향후 폐쇄생태계 생명유지 시스템의 핵심 기술은 우주뿐만 아니라 지구상의 사막, 극지방 또는 해저와 같은 열악한 환경 조건에서도 생명 지원을 가능케 할 것이다.