• 방사성폐기물학회지
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• 제19권1호
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• pp.51-58
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• 2021

Chemical decontamination of primary systems in a nuclear power plant (NPP) prior to commencing the main decommissioning activities is required to reduce radiation exposure during its process. The entire process is repeated until the desired decontamination factor is obtained. To achieve improved decontamination factors over a shorter time with fewer cycles, the appropriate flow characteristics are required. In addition, to prepare an operating procedure that is adaptable to various conditions and situations, the transient analysis results would be required for operator action and system impact assessment. In this study, the flow characteristics in the steady-state and transient conditions for the chemical decontamination operations of the Kori-1 NPP were analyzed and compared via the MARS-KS code simulation. Loss of residual heat removal (RHR) and steam generator tube rupture (SGTR) simulations were conducted for the postulated abnormal events. Loss of RHR results showed the reactor coolant system (RCS) temperature increase, which can damage the reactor coolant pump (RCP)s by its cavitation. The SGTR results indicated a void formation in the RCS interior by the decrease in pressurizer (PZR) pressure, which can cause surface exposure and tripping of the RCPs unless proper actions are taken before the required pressure limit is achieved.

• Medical Lasers
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• 제9권1호
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• pp.65-70
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• 2020

Bronchial foreign body aspiration (BFA) is a common but emergent condition in infants and children. Furthermore, it can result in various complications such as atelectasis, pneumonia, bronchiectasis, and pneumothorax. Among these, pneumothorax is a very rare complication. However, it can be fatal without the swift implementation of appropriate treatment. We experienced a case of 16-month-old girl with an aspirated peanut. The foreign body was fixed in her left main bronchus. A CO₂ laser was used to safely cut and break the foreign body. Removal was successful after breaking it. But after the process, inflammatory tissue of the tracheal mucosa was ruptured. Bilateral tension pneumothorax followed after the rupture. The patient was treated with bilateral chest tube insertion. Here we present this BFA case with a rare and unexpected complication. We also review the appropriate literature.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제26권5호
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• pp.284-289
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• 2023

A 14-year-old girl was admitted to the emergency department for excessive bile-containing vomiting and severe abdominal pain. She had been healthy until she intentionally lost 25 kg over a 6-month period. Thick, bloody bile-mixed food particles were drained from the stomach through a nasogastric tube. Abdominal computed tomography revealed huge stomach dilatation with extensive gastric pneumatosis, possible near rupture, acute pancreatitis, and a very narrow third of the duodenum, indicating superior mesenteric syndrome. Gastrofibroscopy revealed multiple hemorrhagic ulcers and numerous beadlike cystic lesions in the stomach. Laboratory examination results were notable for severe deficiencies in critical nutrients, including iron, zinc, proteins, and prealbumin, as well as undernutrition-associated endocrine complications such as hypothyroidism and hypogonadotropic hypogonadism. Excessive vomiting ceased after the endoscopic removal of stagnant gastric contents. Gastric pneumatosis improved after 3 days of supportive care.

• Journal of Chest Surgery
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• 제40권1호
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• pp.79-82
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• 2007

둔상에 의한 기관-기관지 파열은 발생빈도가 낮은 질환이나, 점차 그 빈도가 증가하는 추세이다. 일단 기관-기관지 파열이 발생하면 매우 심각한 증상을 유발하여 생명의 위협을 초래하고, 많은 합병증을 야기하기 때문에 조기에 진단하여 외과적으로 치료하는 것이 바람직하다 본 저자들은 35세의 남자 환자에서 교통사고 후 발생한 기관 완전 절단의 한 예를 보고하는 바이다. 환자는 수상 후 심한 호흡곤란과 경부, 전흉부에 생긴 피하기종을 주소로 내원하여 양측 긴장성 기흉 진단하에 응급 흉관 삽관술 시행 후에도 대량의 공기 유출이 지속되었고, 피하기종은 복부와 음낭까지 진행되었으며, 호흡부전은 더욱 심화되어 기관-기관지 파열이 강력히 의심되어 응급 수술을 시행하였다. 수술실에서 시행한 술 전 기관지내시경상 성대 하에서 기관의 횡단 절단을 확인하였으며, 수술은 목에 칼라 절개를 가한 후 절단된 기관을 확인하여 4-0 바이크릴(Vicryl) 봉합사를 이용하여 단속봉합에 의한 단단 문합술을 시행하였다. 술 후 흉관을 통한 공기유출은 없었고 기관지내시경 추적 검사상 양호한 소견을 보였으며 특별한 합병증 발병 없이 퇴원하였다.

• 한국방사선학회논문지
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• 제11권5호
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• pp.387-392
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• 2017

영 유아는 사건, 사고 및 교통사고 또는 질병으로 인해 머리에 골절 및 혈관파열, 피부에 상처를 받아 병원에 내원하여 영상의학과에서 머리 검사인 전 후(Skull AP) 및 측면(Skull LAT) 촬영을 받게 된다. 머리검사에서 성인 머리(Skull) 촬영은 격자를 이용하여 촬영에 적용하면 방사선 2차선을 제거하여 영상의 대조도를 높인다. 그러나 방사선 노출조건 중 관전압을 8~10 kVp 높게 주어야 하며 환자피폭이 증가한다. 본 연구는 영 유아 머리촬영시 격자(grid)를 이용하지 않고 동등한 영상을 얻을 수 있다면 피폭선량 감소 및 Grid Cut off에 의한 아티팩트를 방지할 수 있어 연구해 보았다. 연구자는 방사선계측기 이용 방사선선량을 측정 하고 의료영상평가 방법 중에서 주관적 평가(ROC,receiver operationg characteristic)을 해 보았다. 결과에서 격자를 이용하지 않고 촬영하면 환자 피폭선량 감소와 영상 평가에서도 영 유아의 머리 촬영시 격자를 이용하지 않고 촬영을 하게 되면 머리 전 후촬영에서 0.019 mGy 와 측면촬영 0.02 mGy 피폭선량 감소가 있었고 영상평가에서도 4점을 높게 받았다. 결론으로 병원에 내원한 영 유아 머리촬영은 격자를 이용하지 않고 촬영하면 피폭 선량 감소 및 영상 아티팩트인 Grid Cut off을 방지 할 수 있고 엑스선관 수명이 연장되리라 사료된다.

• 한국임상수의학회지
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• 제33권4호
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• pp.237-242
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• 2016

A 1.86 kg, 3-year-old, female, Maltese was presented to the Veterinary Medical Teaching Hospital of Seoul National University after being hit by a car. The patient was diagnosed with urinary bladder rupture, diaphragmatic hernia and fracture of ilium, tibia and fibula. Repair surgery was performed after stabilizing treatment. During the surgery, hypoxia was identified and it worsened after positive pressure ventilation (partial pressure of oxygen in arterial blood ($PaO_2$): 52 mmHg, pulse oximetry ($SpO_2$): 87%, arterial hemoglobin oxygen saturation ($SpO_2$): 85.8%). In addition to hypoxia, blood pressure decreased to 30 mmHg. Positive pressure ventilation was discontinued because hypoxia and hypotension were aggravated. After suturing the diaphragm, air was withdrawn to form negative pressure within the thorax. However, negative pressure was not attained despite continuous withdrawal of air. A thoracostomy tube was placed because tension pneumothorax was strongly suspected. The patient recovered through close monitoring with the tube for 3 days. Due to limitation of evaluation of the lung, predicting occurrence of tension pneumothorax is difficult in patient of diaphragmatic hernia. Therefore, it is recommended that indicators of tension pneumothorax should be closely monitored during diagnosis and repair procedures of diaphragmatic hernia.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.301-301
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• 2003

In current study, Nanocomposites are reinforced with carbon nanofiber, carbon nanotube and SiC, etc. Since the nano reinforcements have the excellent mechanical, thermal and electrical properties compared with that of existing composites, it has lately attracted considerable attention in the various areas. Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties. Until now, strengthening of the copper alloy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the alloy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conducting material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the cooer matrix composites of high strength and electric conductivity. In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process and align mechanism as well as optimized drawing process parameter are verified via numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of 10∼20$\mu\textrm{m}$ in length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper. it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber Optimal parameter for drawing process was obtained by analytical and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc. The lower drawing angles and lower reduction areas provides the less rupture of co tube is noticed during the drawing process and the better alignment of carbon nanofiber is obtained.

• Journal of Chest Surgery
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• 제42권2호
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• pp.263-267
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• 2009

혈성 흉수를 동반한 췌흉강루는 췌가성낭포 파열 혹은 췌관 폐쇄에 의해 생기는 드문 질환이다. 만성 음주력이 있는 48세 남자가 다량의 우측 총수로 내원하였다. 흉수 내 아밀라제와 리파제가 상승되어 있었고, 전산화 단층촬영에서 췌가성낭포 파열에 의한 췌흉강루로 진단되었다. 최초 치료로 흉관 배액, 금식, 총정맥영양 및 췌장액 분비억제제 등의 보존적 치료를 시행하여 증상이 호전되었으나, 이후 출혈성 췌가성낭포가 커지고 혈성 흉수가 재발하여 수술적 치료를 하였다. 환자는 특별한 합병증 없이 수술 후 27일째 퇴원하였다.

• 한국안전학회지
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• 제35권4호
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• pp.84-91
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• 2020

The Korean nuclear industry developed the SPACE (Safety and Performance Analysis Code for nuclear power plants) code and this code adpots two-phase flows, two-fluid, three-field models which are comprised of gas, continuous liquid and droplet fields and has a capability to simulate three-dimensional model. According to the revised law by the Nuclear Safety and Security Commission (NSSC) in Korea, the multiple failure accidents that must be considered for accident management plan of nuclear power plant was determined based on the lessons learned from the Fukushima accident. Generally, to improve the reliability of the calculation results of a safety analysis code, verification work for separate and integral effect experiments is required. In this reason, the goal of this work is to verify calculation capability of SPACE code for multiple failure accident. For this purpose, it was selected the experiment which was conducted to simulate a Multiple Steam Generator Tube Rupture(MSGTR) accident with Passive Auxiliary Feedwater System(PAFS) operation by Korea Atomic Energy Research Institute (KAERI) and focused that the comparison between the experiment results and code calculation results to verify the performance of the SPACE code. The MSGR accident has a unique feature of the penetration of the barrier between the Reactor Coolant System (RCS) and the secondary system resulting from multiple failure of steam generator U-tubes. The PAFS is one of the advanced safety features with passive cooling system to replace a conventional active auxiliary feedwater system. This system is passively capable of condensing steam generated in steam generator and feeding the condensed water to the steam generator by gravity. As the results of overall system transient response using SPACE code showed similar trends with the experimental results such as the system pressure, mass flow rate, and collapsed water level in component. In conclusion, it could be concluded that the SPACE code has sufficient capability to simulate a MSGTR accident.

• Nuclear Engineering and Technology
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• 제47권2호
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• pp.204-211
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• 2015

Probabilistic safety assessment (PSA) has had a significant role in quantitative decision-making by finding design and operational vulnerabilities and evaluating cost-benefit in improving such weak points. In particular, it has been widely used as the core methodology for risk-informed applications (RIAs). Even though the nature of PSA seeks realistic results, there are still "conservative" aspects. One of the sources for the conservatism is the assumptions of safety analysis and the estimation of failure frequency. Surveillance, diagnosis, and prognosis (SDP), utilizing massive databases and information technology, is worth highlighting in terms of its capability for alleviating the conservatism in conventional PSA. This article provides enabling techniques to solidify a method to provide time- and condition-dependent risks by integrating a conventional PSA model with condition monitoring and prognostics techniques. We will discuss how to integrate the results with frequency of initiating events (IEs) and probability of basic events (BEs). Two illustrative examples will be introduced: (1) how the failure probability of a passive system can be evaluated under different plant conditions and (2) how the IE frequency for a steam generator tube rupture (SGTR) can be updated in terms of operating time. We expect that the proposed model can take a role of annunciator to show the variation of core damage frequency (CDF) depending on operational conditions.