• Journal of Korean Neurosurgical Society
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• 제60권6호
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• pp.717-722
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• 2017

Objective : To evaluate the effectiveness and efficacy of delayed burr hole surgery in relation to the reduction of postoperative subdural hematoma (SDH) volume in patients with acute SDH. Methods : We retrospectively analyzed patients with acute SDH who received delayed burr hole surgery at our institute. Age, sex, Glasgow coma scale, maximal SDH thickness, volume of SDH, midline shifts, hounsfield unit (HU), and medical history of anticoagulant agent usage were recorded. Outcome measures were delayed operation day, reduction of SDH volume after operation, and the Glasgow outcome scale (GOS) score at discharge. The patients were divided two groups according to the postoperative reduction of volume of SDH (${\geq}50%$, group A; <50%, group B). We also analyzed variables and differences between two groups. Results : Eighteen patients were available for this analysis. The mean delayed of surgery was $13.9{\pm}7.5$ days. Maximal thickness of SDH was changed from $10.0{\pm}3.5mm$ to $12.2{\pm}3.7mm$. Volume of SDH was changed from $38.7{\pm}28.0mL$ to $42.6{\pm}29.6mL$. Midline shifts were changed from $5.8{\pm}3.3mm$ to $6.6{\pm}3.3mm$. HU were changed from $66.4{\pm}11.2$ to $53.2{\pm}20.6$. Post-operative reduction of SDH volume was $52.1{\pm}21.1%$. Eleven patients (61%) had a discharge GOS score of 1 (good recovery). Ten patients (56%) were enrolled in group A. Midline shifting was greater in group A than in group B ($7.4{\pm}3.3$ vs. $3.0{\pm}2.4mm$; p<0.02). The delay of surgery was shorter for group A than group B ($9.2{\pm}2.3$ vs. $19.8{\pm}7.7$ days; p<0.0008). Conclusion : Among well selected patients, delayed burr hole surgery in patients with acute SDH may be effective for reduction of SDH volume. Further studies will be necessary to establish the effectiveness and safety of delayed burr hole surgery in patients with acute SDH.

• 전력전자학회논문지
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• 제22권6호
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• pp.469-475
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• 2017

Using impedance matching techniques as a way to increase system power transferability in capacitive wireless power transmission has been widely investigated in conventional studies. However, these techniques tend to increase the circuit volume and thus counterbalance the advantage of the simplicity in the energy link structure. In this paper, a compact circuit topology with one leakage-enhanced transformer is proposed in order to minimize the circuit volume for the capacitive power transfer system. This topology achieves a reactive compensation, and the system quality factor value can be reduced by the turn ratio. As a result, this topology not only reduces the overall system volume but also minimizes the voltage stress of the link capacitor. An optimal design guideline for the leakage-enhanced transformer is also presented. The advantages of the proposed scheme over the conventional method in terms of power efficiency and circuit volume are revealed through an analytic comparison. The feasibility of applying the new topology is also verified by conducting 50 W hardware tests.

• 한국자동차공학회논문집
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• 제16권5호
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• pp.68-76
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• 2008

Diesel $NO_x$ reduction by $NH_3$-SCR in conjunction with the effective oxidation precatalyst was analytically investigated. Physicochemical processes in regard to $NH_3$-SCR $NO_x$ reduction and catalytic NO-$NO_2$ conversion are formulated with detailed descriptions on the commanding reactions. A unified model is correctly validated with experimental data in terms of extents of $NO_x$ reduction by SCR and NO-$NO_2$ conversion by DOC. The present deterministic model based on the rate expressions of Langmuir-Hinshelwood reaction scheme finds a conversion extent directly. A series of numerical experiments concomitant with parametric analysis of the $NO_x$ reduction was conducted. $NO_x$ reduction is promoted in proportion to DOC volume ar lower temperatures and an opposite holds at lower space velocity and intermediate temperatures. $NO_x$ conversion is weakly correlated to the space velocity and the DOC volume at higher exhaust temperature. In DOC-SCR system, the $NO_x$ reduction efficiency depends on the $NH_3/NO_x$ ratio.

• 설비공학논문집
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• 제13권12호
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• pp.1266-1274
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• 2001

Heat transfer phenomena during melting process of the phase change material (ice) was studied by numerical analysis and experiments. In a horizontal ice storage tube, the natural convection caused an increase in melting rate. However, the reduction of the heating surface area caused a decrease in melting rate. Therefore, during the melting process of ice in a horizontal cylinder, the reduction of the heating surface area should be considered. Under the same heating wall and initial water temperature condition, the melting rate became higher for $V_s/V_tot/=0.545 \;than \;that\; for\; V_s/V_tot$/=1.00 due to the difference in the reduction of heating surface area. A modified melting model considering the equivalent thermal conductivity of liquid phase and volume reduction was proposed. The results of the model were compared with the measured values and found to be in good agreement.

• Radiation Oncology Journal
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• 제32권2호
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• pp.84-94
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• 2014

Purpose: To quantify the cardiac dose reduction during breathing adapted radiotherapy using Real-time Position Management (RPM) system in the treatment of left-sided breast cancer. Materials and Methods: Twenty-two patients with left-sided breast cancer underwent CT scans during breathing maneuvers including free breathing (FB), deep inspiration breath-hold (DIBH), and end inspiration breath-hold (EIBH). The RPM system was used to monitor respiratory motion, and the in-house self respiration monitoring (SRM) system was used for visual feedback. For each scan, treatment plans were generated and dosimetric parameters from DIBH and EIBH plans were compared to those of FB plans. Results: All patients completed CT scans with different breathing maneuvers. When compared with FB plans, DIBH plans demonstrated significant reductions in irradiated heart volume and the heart $V_{25}$, with the relative reduction of 71% and 70%, respectively (p < 0.001). EIBH plans also resulted in significantly smaller irradiated heart volume and lower heart $V_{25}$ than FB plans, with the relative reduction of 39% and 37%, respectively (p = 0.002). Despite of significant expansion of lung volume using inspiration breath-hold, there were no significant differences in left lung $V_{25}$ among the three plans. Conclusion: In comparison with FB, both DIBH and EIBH plans demonstrated a significant reduction of radiation dose to the heart. In the training course, SRM system was useful and effective in terms of positional reproducibility and patient compliance.

• 한국방재학회 논문집
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• 제11권3호
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• pp.133-141
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• 2011

유역의 도시화는 유출총량과 첨두유량의 증가와 도달시간이 감소시키며, 홍수피해의 위험성을 더욱 크게 만든다. 침투시설은 도시유역의 유출총량과 첨두유량을 감소시킬 수 있고, 그 종류에는 침투트렌치와 투수성 포장재 등이 있다. 본 연구에서는 침투시설 설치에 따른 우수유출저감효과를 알아보기 위하여 경북 구미시 옥계동의 $0.18km^2$와 공단동의 $0.67km^2$의 면적을 가진 도시유역을 대상으로 하여 각각의 유역특성을 분석하고, 유출총량 및 첨두유량의 저감량을 WinSLAMM 모형을 이용하여 분석하였다. 또한, 침투시설 설치에 따른 첨두유량저감효과를 분석하였고, 침투시설 면적비와 유출저감률과의 관계식을 도출하였다.

• 대한금속재료학회지
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• 제48권4호
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• pp.315-319
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• 2010

In this study, the hydrogen reduction behavior of ball-milled NiO nanopowder was investigated depending on the partial pressure of water vapor. The hydrogen reduction behavior was analyzed by thermogravimetry and hygrometry under heating to 873 K in hydrogen. In order to change the partial pressure of the water vapor, the dew point of hydrogen was controlled in the range of 248 K~293 K by passing high-purity hydrogen through a saturator that contained water. Interestingly, with the increase in the dew point of the hydrogen atmosphere, the first step of the hydrogen reduction process decreased and the second step gradually increased. After the first step, a pore volume analysis revealed that the pore size distribution in the condition with a higher water vapor pressure shifted to a larger size, whereas the opposite appearedat a lower pressure. Thus, it was found that the decrease in the pore volume during the chemical reaction controlled process at a dew point of 248 K caused a reduction in retardation in the diffusion controlled process.

• 한국전문물리치료학회지
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• 제10권3호
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• pp.53-61
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• 2003

The purpose of this study was to determine the effects On the lymphedema patients of sponge padding and the correlation between the rate of edema reduction and downward shifting of bandages. Fifty secondary lymphedema patients with no infection, active cancer, limitation of movement, pain or drugs were randomly assigned to two groups: a sponge padding group, and a cotton padding group. Complex decongestive therapy was applied for 2 weeks. In each group the volume of the ankle, mid-calf, knee, and mid-thigh and downward shifting of bandages at the thigh was measured with measuring tape. The reduction of volume and downward shifting of bandages were analyzed by the unrelated t-test and the Pearson Correlation Test. The results were as follows: 1. In comparison between the sponge padding group and the cotton padding group, there was no significant difference in volume except in the thigh area. The edema volume was reduced significantly to $37.77{\pm}31.15%$ at the thigh with sponge padding after treatment (p<.05). 2. Bandage shifted 10.12 cm with cotton padding, but only shifted 2.85 cm when sponge padding was used. Sponge padding had an excellent effect in preventing the shifting of bandages. There was a significant difference in the amount of shifting that occurred with each type of padding (p<.05). 3. There was also a strong correlation between the reduction of edema and the shifting of bandage. These results suggest that short-stretch bandaging with sponge padding is more effective than bandaging with cotton padding. Further study on skin irritation and the comfort of sponge padding is needed to use padding materials safely and effectively.

• Journal of Chest Surgery
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• 제30권8호
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• pp.827-832
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• 1997

폐용적 감축술(Lung volume reduction surgery : Lns)은 최근들어 활동이 어려운 심한 폐기종 환자에서 폐이식의 대체요법이나 폐이식의 전단계 시술로 추천되고 있다. 이 시술은 폐기종 환자의 호흡곤란을 감소 시키고 일상생활의 수행을 개선시키기 위한 고식적인 치료방법이다. 범발성 폐기종 환자에 대한 폐용적 감축술(LVRS)의 개념은 병변이 심한 기능이 없는 폐를 절제함으로써 남아있는 병변이 적은 폐의 기능을 개선 시킨다는 것이다. 폐용적 감축술UnS)의 성공에 결정적인 영향을 미치는 요소들로는 철저한 환자의 선택 (patient selection), 정확한 수술부위의 위치선정, 신중한 마취 및 수술기법, 그리고 집중적인 술후 처치 등이 있다. 본 병원에서는 심한 폐기종으로 입원한 59세 남자환자에서 철저한 선택과정patient selection)과 호흡기재활 (pulmonary rehabilitation)을 거쳐 흉강내시경을 이용하여 폐용적 감축술InnS)을 시행하였으며 술후 경과 양 호하녀 퇴원 후 현재 외래 추적관찰 중이다.

• Korean Journal of Radiology
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• 제22권6호
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• pp.944-950
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• 2021

Objective: To demonstrate the feasibility of percutaneous microwave ablation in desmoid fibromatosis with respect to tumor volume control and improvement in the quality of life. Materials and Methods: Twelve microwave ablations were performed in 9 patients with a histological diagnosis of desmoid fibromatosis between January 2010 and January 2019. The study population included 6 female and 3 male, with an age range of 21-76 years (mean = 46.6 years; standard deviation [SD] = 19.3 years). The mean major axis of the tumors was 10.9 cm (SD = 5.2 cm) and mean lesion volume was 212.7 cm³ (SD = 213 cm³). Their anatomical distribution was as follows: 3 lesions in the thigh, 2 in the gluteus, 2 in the leg and 2 in the periscapular region. We evaluated the reduction in tumor volume and improvement in the quality of life based on the Eastern Cooperative Oncology Group (ECOG) scale. Results: An average tumor volume reduction of 70.4% (SD = 24.9) was achieved, while the quality of life (ECOG scale) improved in 88.9% of patients. Conclusion: Percutaneous microwave ablation may potentially be a safe, effective, and promising technique for controlling tumor volume and improving the quality of life in patients with desmoid fibromatosis.