• 에너지공학
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• 제25권3호
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• pp.59-65
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• 2016

MVR 증발법은 담수의 증발을 위해 연료를 지속적으로 연소시켜 나오는 열에너지를 이용하지 않고 대신 전기압축기를 통해 증발된 증기를 압축시켜 고온으로 만들고, 이를 다시 열교환기를 통해 재활용함으로써 에너지의 소비를 최소화하는 방식이다. MVR 증발법은 안정적이라 할 수 있는 계통선에 의해 공급되는 전기 대신 가변적인 풍력에너지를 그 에너지원으로 활용하여 담수 생산을 꾀할 수 있다. 본 연구에서는 일일 담수 생산량이 30 톤인 제주 MVR 담수화 시스템의 설계, 제작 그리고 작동 과정에 대하여 살펴보고자 하였다. 실험결과, MVR 압축비는 1.5 이상이며 주열교환기의 온도차는 $5{\sim}7^{\circ}C$로 설계치와 동일한 성능을 보여준다.

• Journal of Chest Surgery
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• 제20권2호
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• pp.289-299
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• 1987

A total of 1,239 patients had cardiac valve replacement using 1,514 substitute valves at Seoul National University Hospital from 1968 to 1986. Of the total substitute vales, 84.9% were the glutaraldehyde-treated xenograft valves. Six hundred ninety-four patients who had 820 bioprosthetic tissue valves were studied for their clinical characteristics. They were a total and consecutive cases to the end of the study. Four hundred sixty-four patients had the lonescu-Shiley pericardial valves: MVR 291, AVR 66 and MVR+AVR 107; 163 had the Hancock porcine valves; 46 had the Angell-Shiley porcine valves; and 21 had the Carpentier-Edwards porcine valves. Five hundred forty patients underwent single valve replacement: MVR 460, AVR 76 and TVR 4; 154 had multiple valve replacement: MVR+AVR 141, MVR+TVR 12 and one triple valve replacement. Additional surgery was necessary in 22.3% of the cases. Operative mortality rate within 30 days of surgery was 6.77% for the total patients: 5.2% and 4.2% with MVR, 13.6% and 12.5% with AVR, and 7.5% and 7.4% with MVR+AVR using the lonescu and the Hancock valves respectively. A linealized annual late mortality rate was 2.56%/patient-year. Six hundred forty-three operative survivors were followed up for a total of 1482.7 patient-years [a mean 27.7 months], and the follow-up rate was 67.7%. The Idealized complication rates were: 2.02% emboli/patient-year, 0.94% bleeding/patient-year, 1.21% endocarditis/patient-year, and 3.84% overall valve failure/patient-year. A linealized rate of primary tissue failure was 0.87%/patient-year. Actuarial survival rates including the operative mortality were: 87.8*2.6%, 82.3*4.9% and 82.2*4.7% with MVR, AVR and MVR+AVR using the lonescu valves at 4 years after surgery respectively; and they were 88.0*4.1% with MVR at 8 years, 82.3*4.9% with AVR at 4 years and 84.9*7.0% with MVR+AVR at 6 years after surgery using the Hancock valves respectively. Probabilities of freedom from thromboembolism were 89.8*6.3% with MVR using the lonescu valves at postoperative 5 years and 89.2*3.8% with MVR using the Hancock valves at postoperative 7 years, and 93.3*3.9% with AVR using the lonescu valves at postoperative 5 years. None had embolic complication after AVR using the Hancock valves. Probabilities of freedom from valve failure [according to the Stanford criteria] were 81.0*7.1% with MVR using the lonescu valves at postoperative 4 years and 57.4*12.5% with MVR using the Hancock valves at postoperative 9 years. These clinical results prove the excellent antithrombogenicity of the glutaraldehyde-treated xenograft substitute valves and confirm the previously speculated rate of tissue failure. At the present situation, it may be concluded that there is a room for the further development of more durable bioprosthetic valves.

• 설비공학논문집
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• 제27권4호
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• pp.201-206
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• 2015

The MVR was theoretically modeled by performing the polytropic process, and the polytropic coefficient was estimated by using the performance curve provided by the manufacturers. The TVR was investigated by applying the conservation equations to the movement of fluids inside the TVR. The size of the nozzle and diffuser was determined. Theoretical MVR and TVR modeling was verified by comparing the results of the model with the available design data. Besides, the effects of multi-staging of the MVR on power consumption, and the effects of suction and primary pressure on the sizing of TVR were investigated.

• Journal of Chest Surgery
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• 제15권2호
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• pp.213-217
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• 1982

We recently experienced Redo MVR to the patient who had received MVR due to MSI by Angell-Shiley porcine xenograft at SNUH 3 years ago. Three months ago, infective endocarditis developed and heart failure progressed so he revisit our hospital and diagnosed prosthetic valve failure. He received MVR again with Ionescu-Shiley valve and discharged somewhat improved state.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 2002년도 춘계 학술논문발표회 논문집
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• pp.171-176
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• 2002

이 논문은 MVR(Machinery Vapor Recompressor) Impeller Blade의 파손으로 발생한 사고원인 조사Um 관한 것이다 MVR의 고장의 원인을 밝히기 위해서 육안 분석(visual examination), 실체현미경 분석(Stereoscopic examination), SEM 분석 (SEM examination)을 한 결과 주조결함으로 인한 Surface Crack이 장기간 지속되어 Initial Crack이 생성된 뒤에 이 부위에 응력이 집중되면서 Fatigue Crack이 임계 Crack 길이까지 진행되었다. 여기에 Impeller 회전속도의 상승으로 인한 과부하가 부가되어 MVR의 Blade가 파손된 것을 알 수 있었다.(중략)

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.482-486
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• 2003

A high-efficiency turbo steam compressor has been successfully developed for the MVR desalination system, first one in Korea. The state-of-the-art design methods using real gas properties were applied to get all the aerodynamic design results. Bull and pinion gear trains, tilting-pad bearings and investment cast impellers were developed also to be integrated into the integral gear-driven turbo steam compressor. System tests show highly efficient performance.

• 에너지공학
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• 제25권4호
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• pp.1-6
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• 2016

일반적으로 해수담수화플랜트는 크게 두 가지의 문제점을 가지고 있는데, 에너지 비효율성과 해수담수화 후 부산물인 농축수의 해결방안이다. 전자는 태양에너지 등 신 재생에너지원의 활용과 새로운 기술에 대한 꾸준한 연구개발로 상당히 그 효율성이 개선되었으나, 농축수 해결방안에 대한 연구는 아직 미미한 실정이다. 본 논문에서는 많은 에너지를 투입하여 담수와 함께 생산된 농축수의 활용과 관련하여 제염이 가능한 설비의 구축과 그 효용성을 제고하기 위한 미네랄(Mg) 성분 제어에 관하여 제주 MVR해수담수화 플랜트를 중심으로 그 연구 결과를 소개하고자 한다. 플랜트의 정상 작동으로 생산된 농축수에 본 연구의 제염 설비를 적용하여 단계별 소금의 성분 함량을 분석했을 때 Mg 성분 수치가 줄어드는 것으로 보아 미네랄(Mg) 제어가 정상적으로 진행되고 있음을 알 수 있었다. 아울러, 본 MVR해수담수화 플랜트의 에너지 이용의 효율성과 담수 생산 및 농축수 활용에 관하여 그 활용성을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.941-942
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• 2006

The Analysis on AVR-MVR conversion trouble for Excitation System AVR-MVR conversion is a very important function to transfer AVR to MVR when the grid has abrupt changes or the control system has some problems. Therefore through studying on AVR-MVR transfer scheme, and problems which might happen when transferring, we would like to enhance the stability of generator and control system.

• Journal of Chest Surgery
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• 제40권10호
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• pp.659-666
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• 2007

배경: 승모판막하부 구조물의 보존은 판막대치술에서 심실 기능을 보존하고 임상경과를 향상시킨다. 판막성형술에서도 구조물의 보존으로 인해 예후가 좋다고 알려져 있지만 지금까지 판막성형술과 보존적 판막대치술 간에 수술 직후 심기능을 비교한 연구는 많지 않다. 이에 본 연구에서는 상기 두 술식에 따른 혈역학적 차이와 임상경과를 전향적으로 비교 연구하였다. 대상 및 방법: 승모판막폐쇄부전을 진단받은 54명의 환자 중 21명에서 보존적 판막대치술을, 33명에서 판막성형술을 시행하였다. 수술 중과 후에 환자의 혈역학, 심혈관계 약물의 사용, 임상경과 및 합병증을 관찰하였다. 모든 환자에서 최소 6개월 이상 사망률과 이환율을 추적 관찰하였다. 결과: 두 군 간 환자군의 특징은 비슷하였다. 다만 심방세동과 심부전이 판막대치술군에서 많았고 술 전 좌심실박출계수가 판막대치술군에서 $64{\pm}9%$로 판막성형술군의 $69{\pm}5%$에 비해 낮았다(p=0.043). 두 군 간 수술 중과 중환자실에서의 혈역학적 차이는 없었다. 중환실에서 심근수축제 사용 빈도는 판막대치술군에서 48%로 판막성형술군의 24%에 비해 유의하게 많았다(p=0.025). 또한 중환실에서 심장박동조율기 사용은 판막대치술군에서 52%로 판막성형술군의 24%에 비해 유의하게 많았다(p=0.035). 6개월 이상의 추적관찰 중 임상경과는 비슷하였다. 결론: 보존적 판막대치술은 술 후 혈역학과 단기적 임상경과 추적관찰 소견상 판막성형술과 필적한 결과를 보였다. 이는 수술 직후에 보존적 판막대치술이 판막성형술과 비슷한 유리한 영향을 미치기 때문으로 생각한다.

• Journal of Chest Surgery
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• 제14권4호
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• pp.369-380
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• 1981

In this department 504 cases of valve replacement were done since 1968 to the end of October 1981. Since October 31, 1978 to the end of October 1981 ,333 Ionescu-Shiley bovine pericardial xenograft bioprosthetic cardiac valves were replaced in 265 patients. There were 149 males and 116 female. Ages ranged from 2 to 63 years with 25 cases under 15 years of age. Among 265 cases of Ionescu valve replacement there were 157 MVR, 36 VAR, 6 TVR, 45 MVR+ AVR, 16 MVR+TVR and 5 MVR+AVR+TVR cases with mortality of 5.7%, 8.3%, 16.7%, 8.9%, 18.8% and 20% for each group respectively. Over all mortality rate in 265 Ionescu valve replacement cases was 7.9% with 21 total deaths. Main causes of operative deaths were due to LCOS in 7, bleeding in 5, arrhythmia in 3, air embolism in 2,and heart block in 2 cases. There were 12 late complications with 6 deaths. Over all long-term survival rate was 89.8%. MVR showed the highest long-term survival rate with 92.4%, and MVR+AVR+TVR the lower with 80% lower with 80%.Average follow-up period was 14 month duration. Twenty five congenital anomaly cases were operated with Ionescu-valve replacement that consisted of 7 VSD+AI, and 5 Ebstein anomaly cases with over all operative mortality of 16% and late mortality of 14.3% among 21 operative survivors. There were 25 Ionescu valve replacement cases in pediatric patients under the age of 15 years, with 4 operative deaths. Fourteen MVR, 7 AVR, and 3 TVR cases were found. Even though long-term follow-up study was short in postoperative period with total of 33~.0 months among 244 operative survivors ranging one to 36 months, the late survivors showed beneficial long-term results two thromboembolic episodes in 244 patients were found. More cases and longer term follow-up study are warranted for valve replacement in pediatric and TVR cases with Ionescu-valves which have advantageous hemodynamic structures compared with other bio-prosthetic heart valves.