• 시스템엔지니어링학술지
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• 제17권1호
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• pp.11-20
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• 2021

Decontamination of systems, structures and components (SSC) during the decommissioning of a Nuclear Power Plant (NPP) can be for a variety of reasons. The main reasons for decontamination are: to reduce the contamination of SSC to a reasonably low level, to reduce the potential for the spread of contaminants into the environment and to reduce the cost of disposal due to the reduced level of contamination in a particular SSC. The decontamination technique can be aggressive or non-aggressive depending on the intent after the decontamination process. Aggressive decontamination technique is used when the intent is not to reuse the SSC while a non-aggressive decontamination technique is used with the intent of SSC reuse. For different SSCs there are different decontamination techniques that can be used, each having its own advantages and drawbacks. Metal components such as pipes in the nuclear power plant account for a large amount of nuclear wastes generated. Some of these wastes can be reused if the contaminant level is reduced to an acceptable level. Laser ablation is a non-aggressive decontamination technique that can be used to reduce the contamination in pipes to an acceptable level with no secondary waste generated during the process. The operation and control of a laser ablation device must be precise to achieve a high decontamination factor. This precision can be achieved by a well-designed motion control system. For this purpose, a motion control system was developed consisting of two parts: the first part being the precise control of the laser ablation device inside the pipe and the second part is the control of the laser ablation device outside the pipe. This paper describes the Systems Engineering approach for the development process of a motion control system for the Laser decontamination system.

• 대한영상의학회지
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• 제84권5호
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• pp.1017-1030
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• 2023

증상이 있는 양성 갑상선결절의 비수술적 치료법인 고주파 절제술은 결절 조직을 열로 소작하여 부피를 감소시키고, 이로 인해 증상의 완화와 외견상 문제를 해결한다. 고주파절제술의 적응증은 2회 이상 세포/조직검사로 양성이 확인된 결절에서 의학적 치료가 필요한 주관적 또는 외견상의 임상증상이 있는 경우이다. 고주파 절제술은 1년의 단기 추적에서 매우 양호한 성적을 보이지만 3년 이상의 장기 추적에서는 20%-30% 결절의 재성장이 발생한다. 따라서 장기 추적을 전제로 하는 고주파절제술 후 환자 관리에서는 재성장을 관리하는 것이 핵심이다. 재성장은 치료 전 결절부피가 큰 경우, 혈관성이 높거나 증가하는 경우 잘 발생하며, 최근에는 수분 박리(hydrodissection), 동맥우선소작법, 정맥소작법등 새로운 기술들이 도입되어 재성장을 억제하고 있다. 또한 적절한 기준을 적용하여 재치료를 하는 것이 재성장을 관리하고 치료 효과를 오래 지속시키는데 중요하다. 고주파 절제술은 근본적으로 수술의 대안이므로 일시적 효과를 거두는 것이 아니라 영구적으로 수술을 회피하도록 하는 것이 궁극적인 목표이다.

• The Korean Journal of Pain
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• 제36권4호
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• pp.450-457
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• 2023

Background: Genicular nerve neurolysis with phenol and radiofrequency ablation (RFA) are two interventional techniques for treating chronic refractory knee osteoarthritis (KOA) pain. This study aimed to compare the efficacy and adverse effects of both techniques. Methods: Sixty-four patients responding to diagnostic blockade of the superior medial, superior lateral, and inferior medial genicular nerve under ultrasound guidance were randomly divided into two groups: Group P (2 mL phenol for each genicular nerve) and Group R (RFA 80℃ for 60 seconds for each genicular nerve). The numeric rating scale (NRS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were used to evaluate the effectiveness of the interventions. Results: RFA and phenol neurolysis of the genicular nerves provided effective analgesia within groups at 1 week, 1 month, and 3 months compared to baseline. There was no significant difference between the groups in terms of NRS and WOMAC scores at all measurement times. At the 3rd month follow-up, 50% or more pain relief was observed in 53.1% of patients in Group P and 50% of patients in Group R. The rate of transient paresthesia was 34.4% in Group P and 6.3% in Group R, and this was significantly higher in Group P. Conclusions: Neurolysis of the genicular nerves with both RFA and phenol is effective in the management of KOA pain. Phenol may be a good alternative to RFA. Further studies are needed on issues such as dose adjustment to prevent transient paresthesia response.

• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.68-71
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• 2008

Transdermal and topical drug delivery with minimal tissue damage has been an area of vigorous research for a number of years. Our research team has initiated the development of an effective method for delivering drug particles across the skin (transdermal) for systemic circulation, and to localized (topical) areas. The device consists of a micro particle acceleration system based on laser ablation that can be integrated with endoscopic surgical techniques. A layer of micro particles is deposited on the surface of a thin metal foil. The rear side of the foil is irradiated with a laser beam, which generates a shockwave that travels through the foil. When the shockwave reaches the end of the foil, it is reflected as an expansion wave and causes instantaneous deformation of the foil in the opposite direction. Due to this sudden deformation, the microparticles are ejected from the foil at very high speeds, and therefore have sufficient momentum to penetrate soft body tissues. We have demonstrated this by successfully delivering cobalt particles $3\;{\mu}m$ in diameter into gelatin models that represent soft tissue with remarkable penetration depth.

• Archives of Plastic Surgery
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• 제42권1호
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• pp.52-58
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• 2015

Background The erbium:yttrium scandium gallium garnet (Er:YSGG) laser differs from other laser techniques by having a faster and higher cure rate. Since the Er:YSGG laser causes an appropriate proportion of ablation and coagulation, it has advantages over the conventional carbon dioxide ($CO_2$) laser and the erbium-doped yttrium aluminum garnet (Er:YAG) laser, including heating tendencies and explosive vaporization. This research was conducted to explore the effects and safety of the Er:YSGG laser. Methods Twenty patients participated in the pilot study of a resurfacing system using a 2,790-nm Er:YSGG laser. All patients received facial treatment by the 2,790-nm Er:YSGG laser system (Cutera) twice with a 4-week interval. Wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture were measured. Results Study subjects included 15 women and five men. Re-epithelization occurred in all subjects 3 to 4 days after treatment, and wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture within 6 months of treatment. Conclusions The 2,790-nm YSGG laser technique had fewer complications and was effective in the improvement of scars, pores, wrinkles, and skin tone and color with one or two treatments. We expect this method to be effective for people with acne scars, pore scars, deep wrinkles, and uneven skin texture and color.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권11호
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• pp.527-532
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• 2005

During the last ten years the new interruption techniques, which use the arc energy itself to increase the pressure inside a chamber by the PTFE nozzle ablation, have displaced the puffer circuit breakers due to reduced driving forces and better maintainability. In this paper, we have investigated the thermal flow characteristics inside a thermal puffer type gas circuit breaker by solving the Wavier-Stokes equations coupled with Maxwell's equations for considering all instabilities effects such as turbulence and Lorentz forces by transient arc plasmas. These relative inexpensive computer simulations might help the engineer research and design the new interrupter in order to downscale and uprating the GIS integral.

• Archives of Plastic Surgery
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• 제36권2호
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• pp.205-210
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• 2009

Purpose: Corrugator supercilii muscle pulls eyebrow to inferomedial direction and produces the vertical component of the glabellar line formation. Current techniques for eliminating of glabellar frown include direct resection of corrugators and botulinum toxin injection. Muscle resection in endoscopic face lift procedure is relatively complex and has many disadvantages ranging from possible nerve injury, postoperative edema, pain and a long recovery period. The Botox treatment on the other hand is much more simple in technique but has a short duration of action. The authors have attempted new ways of finding improved treatment of the glabellar frown by selectively blocking of motor nerves innervating the corrugator supercili muscle by using radiofrequency ablation technique. Methods: A total of 80 patients were recruited in our study during the period between Feb. 2007 to June 2008. A probe was introduced from the supraorbital ridge and advanced to the corrugator supercilii muscle. Nerve stimulator was then used to locate the nerve innervating the corrugator and radiofrequency ablation of the nerve was done. Results: In all patients, there were marked improvement in glabellar frown after treatment. There were no reported cases of any relapses during the follow up period. No complication was noted such as facial nerve injury. No patient complained of any adverse symptoms other than slight discomfort due to swelling of the operation site. Conclusion: The treatment of glabellar frown lines using selective nerve block with radiofrequency ablation was not only less invasive but also excellent in surgical outcomes.

• Mass Spectrometry Letters
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• 제6권4호
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• pp.85-90
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• 2015

This article reviews recent analytical techniques using inductively coupled plasma-mass spectrometry (ICP-MS) immunoassay for clinical and bio analysis. We classified the techniques into two categories, direct and indirect analysis, which depend upon a guideline of whether tagging materials are used or not. Direct analysis is well known, and generally used in conjunction with various other techniques, such as laser ablation, chromatographic separations, etc. Recently, indirect analysis using tagging elements has intensively been discussed because of its importance in future applications to bio and clinical analysis, including environmental and food industries. The method has shown advantages of multiplex detection, excellent sensitivity, and short analysis time owing to signal amplification and magnetic separation. Now, it expands the application field from small biomolecules to large cells.

• 대한방사선기술학회지:방사선기술과학
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• 제38권2호
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• pp.155-161
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• 2015

본 연구는 고주파 열치료 시 내부냉각방식 cool-tip의 냉각수 온도에 따른 소작 특성을 확인하기 위하여 소간을 이용하여 냉각수 온도변화에 따른 소간의 소작 특성의 변화를 통해 냉각수 온도변화와 소작 특성의 상관관계를 확인하고자 하였다. 실험에 사용된 소간은 2 cm cool-tip 사용 시 $4{\times}4{\times}4cm^3$, 3 cm인 cool-tip 사용 시에는 $6{\times}6{\times}6cm^3$로 소간을 절제하였으며, 소작된 소간은 MRI를 이용하여 영상검사를 실시하였으며, Freehand 기법으로 소작된 부위의 면적과 둘레를 측정하였다. 2 cm, 3 cm cool-tip을 사용하여 6분, 12분 소작 시 cool-tip 온도가 상승함에 따라 면적과 둘레는 감소함을 나타냈으며, cool-tip 온도와 면적 및 둘레의 상관관계는 통계학적으로 유의한 결과를 나타내었다(p=.000). 소작 범위에 대한 실제 측정과 MRI을 이용한 측정을 비교한 결과 MRI를 이용한 면적과 둘레 측정이 더 정확한 것을 확인하였으며, 대응표본 T-검정을 이용한 통계적 결과 또한 유의하였다(p=.038). 고주파 열치료 장비의 cool-tip 냉각수 온도가 증가함에 따라 소간의 소작 범위가 감소한 원인은 고주파 열치료 장비의 에너지가 정확히 전달되지 못하고 탄화가 발생하기 때문이다. 따라서 고주파 열치료에서 탄화의 발생을 줄이고, 고주파 에너지가 정확히 전달되어 치료 효과를 높이기 위해서는 냉각수의 온도를 낮은 온도로 일정하게 유지하여 사용하여야 고주파 열치료의 효과가 증대될 것이라 사료된다.

• 전기전자학회논문지
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• 제25권3호
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• pp.540-543
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• 2021

본 논문에서는 비행체의 궤적 예측에 적절한 순환 신경망 기반 기법을 탐구하기 위하여 정량적인 비교 평가 연구를 수행하였다. 이를 위해 본 논문에서는 비행체의 궤적 예측 작업을 수행하기 위한 다양한 입력 및 출력 관계들을 정의하고 동일한 실험 환경에서 비교 평가하였다. 특히 비행체 위치의 상대값 기반 입출력 관계를 제안하여 비행체의 궤적 예측에 적합함을 보였다. 또한 비행체 궤적 예측에 효율적인 네트워크 구조 및 하이퍼파라미터를 결정하기 위한 다양한 ablation study(비교 실험)를 진행하였다. 본 논문에서 제시된 정량적 비교 평가 결과는 비행체의 궤적 예측을 위해 순환 신경망 기반 기법을 이용하거나 비행체의 궤적 예측에 특화된 딥러닝 기법을 연구하고자 하는 연구자 및 개발자들에게 실질적인 도움이 될 것으로 예상된다.