• 한국입자에어로졸학회지
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• 제17권2호
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• pp.21-27
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• 2021

We developed non-metallic electrodes that can replace metallic electrodes of the electrostatic precipitator(ESP) for the purpose of light weight, corrosion resistance, cost reduction. We manufactured three types of collection electrodes made of stainless steel (M), Carbon ink coating layer-Plastic sheet-Carbon ink coating layer (CPC), and Plastic sheet-Carbon ink coating layer-Plastic sheet (PCP). We studied the collection efficiency of a two-stage ESP using oil mist particles with and without collection stage by changing the flow rate, the material of collection electrode, and the applied voltage of the pre-charger module and the collection module. Here we measured concentrations of particles at diameters of 0.45 ㎛ (CMD; count median diameter) and 3.0 ㎛ (MMD : mass median diameter), as well as PM_2.5 and PM₁₀. As a result of the experiment, two-stage ESP had 22~25% higher collection efficiency in PM_2.5 than one-stage ESP at the same applied voltage. The difference in collection efficiency by varying the materials of collection electrodes was less than 5%. The weight of the non-metallic electrode was only one eighth the weight of the metal electrode. CPC electrode had a thickness of 0.27 mm, which was 1.5 times thinner than a thickness of PCP electrode, so when the flow rate increased, the CPC electrodes couldn't be kept at equal intervals due to the fluttering unlike PCP electrodes. In addition, the PCP-CPC collection module of the present experiment followed the theoretical efficiency based on Deutsch equation and Cochet's charging theory.

• 한국가금학회지
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• 제48권4호
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• pp.169-176
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• 2021

본 실험은 산란후기의 공시계에서 가수분해 효모의 수준별 급여를 통해 난 생산성과 난질을 평가하고 평가된 데이터를 기본으로 하여 보조사료적 가치를 검토하기 위하여 수행하였다. 58주령 하이라인 실용 갈색계 총 180수를 공시하여 3개 처리에 6반복 반복당 10수를 임의배치 하였고 가수분해 효모를 0, 0.1 및 0.2% 수준으로 첨가한 실험사료를 8주간 급여하였다. 첫 전기 4주간의 산란율과 일산란량에서는 처리간에 큰 차이가 없었으나, 후기 4주간 동안 대조구에 비하여 가수분해 효모를 첨가한 실험구의 산란율과 일산란량이 유의하게 높은 것으로 나타났다(P<0.05). 난중은 처리간에 큰 차이가 없었다. 전체 실험기간 중의 난각강도와 난각두께는 가수분해 효모 첨가구에서 유의하게 높은 결과가 관찰되었다(P<0.05). 호우유니트에서는 처리간에 차이가 없었으나 난황색은 가수분해 효모 0.1% 첨가구에서 대조구에 비하여 유의하게 높았다(P<0.05). 난각 미세구조에서 유두층은 가수분해 효모 급여에 따라 선형적으로 증가하는 결과가 관찰되었다(P<0.05). 가수분해 효모 0.2% 첨가구에서 가금 인플루엔자 바이러스에 대한 항체역가가 유의하게 증가하였다(P<0.05). 결론적으로 가수분해 효모의 첨가 급여에 의해 산란후기의 난 생산성이 부분적으로 개선되었고, 난질 및 난각질이 유의하게 향상됨으로서 산란계의 후기 생산단계에 효과적으로 적용할 수 있음이 시사되었다.

• 동의신경정신과학회지
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• 제34권3호
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• pp.141-150
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• 2023

Objectives: This study aimed to comprehend the characteristics of Korean medicine patterns in relation to varying degrees of cognitive impairment in an elderly population. Methods: The dataset included 127 elderly individuals with cognitive impairment obtained from three Korean medicine hospitals between 2018 and 2021. The participants were categorized into two groups based on Clinical Dementia Rating-Sum of Boxes (CDR-SB) scores: those with questionable impairment (QI) and those with very mild dementia (VMD). A diagnostic framework for Korean medicine patterns encompassing Qi deficiency, Yin deficiency, Phlegm dampness, and Heat-fire was employed. Liver blood markers, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the AST/ALT ratio, were also analyzed. Results: The scores of the cognitive assessment tools (MoCA-K, MMSE-DS, and K-IADL) of the QI group significantly differed from those of the VMD group. CDR-SB exhibited a positive correlation with the scores of each pattern of Qi deficiency, Yin deficiency, Phlegm dampness, and Heat-fire, whereas ALT and AST values displayed negative correlations. Binomial logistic analysis, controlling for potential confounders, such as age, education years, body mass index, the presence of chronic disease, and the presence of medication, verified that the VMD group showed higher pattern scores and lower ALT and AST values than the QI group. Conclusions: Increases in pattern scores along with decreased AST and ALT levels might be indicative of more severe cognitive impairment.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제12권3호
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• pp.133-140
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• 2023

리튬 이온 배터리는 사용 환경과 양극재 조합 비율에 따라 배터리의 성능이 좌우된다. 고성능 리튬 이온 배터리를 개발하기 위해서는 양극재 비율을 다양하게 변화시켜가면서 배터리를 제작하고 성능을 측정해야 한다. 하지만 모든 변수 조합에 대해 배터리를 제작하고 성능을 측정하기에는 많은 시간과 비용이 소모된다. 그렇기 때문에 최근에는 데이터 기반으로 인공지능 모델을 활용하여 배터리의 성능을 예측하고자 하는 연구가 활발히 진행되고 있다. 그러나 기존 공개 배터리 데이터는 동일한 배터리로 측정 실험을 하였기 때문에 양극재 조합 비율은 고정되어 있어서 데이터 속성으로 포함되지 않았다. 본 논문에서는 양극재 소재 조합 비율에 따른 배터리의 성능을 예측할 수 있는 인공지능 모델 개발에 필요한 학습 데이터 모델을 정의한다. 우리는 리튬 이온 배터리의 성능에 영향을 미칠 수 있는 요인을 분석하여 양극재 소재별 질량과 배터리 사용 환경을 입력데이터로, 배터리의 출력과 용량을 목적 데이터로 정의하였다. 공개 배터리 데이터 중에는 양극재 비율이 포함된 데이터가 없어 양극재 비율을 모두 동일한 값으로 설정한 제한된 데이터로 다중 선형회귀 분석, 서포트 벡터 회귀분석, 다중 로지스틱 회귀 분석, LSTM 분석을 수행하였다. 실험 환경이 다른 배터리 데이터에서 각각의 배터리 데이터는 고유한 패턴을 유지하였으며, 배터리 분류 모델은 각각의 배터리를 약 2%의 오차로 분류하는 것으로 나타났다.

• 한국해양바이오학회지
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• 제15권2호
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• pp.82-89
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• 2023

Microalgae, as photosynthetic organisms, possess the ability to produce a diverse array of bioactive compounds. This study focused on the transformant Chlamydomonas reinhardtii dZL and subjected it to cultivation under varying light intensities (60, 120, 180, and 240 µmol/m²/s). Our aim was to assess the impact of light intensity on both microalgal biomass and carotenoid production. The cultivation took place in 80 mL bubble column photobioreactors, specifically the Multi-cultivator. Notably, the culture exposed to 240 µmol/m²/s exhibited the most rapid cell growth, surpassing even the cell concentration achieved at 180 µmol/m²/s by day 8. A detailed analysis of the specific irradiance rate over time unequivocally revealed a sharp decline in growth rates when the rate fell below 2 × 10^-10 µmol/cell/s. Although the culture with 60 µmol/m²/s yielded the highest carotenoid content (1.2% of dry weight), the culture exposed to 240 µmol/m²/s recorded the highest carotenoid concentration at 8.9 mg/L owing to its higher biomass. Our findings reveal the critical importance of maintaining a specific irradiance rate above 2 × 10^-10 µmol/cell/s to enhance biomass and carotenoid productivity. This study lays the groundwork for defining optimal light intensity conditions applicable to mass culture systems, with the objective of augmenting C. reinhardtii biomass and optimizing carotenoid productivity.

• 대한영상의학회지
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• 제85권1호
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• pp.3-23
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• 2024

임상에서 자주 접하게 되는 추간판탈출증 중 분리추간판은 추간판의 성분이 원래의 수질핵과 완전히 분리되는 특별한 경우를 의미한다. 이러한 분리추간판은 척추관 내부뿐만 아니라 외부에도 위치할 수 있으며, 주변 구조물에 압력을 가하거나 신경 경로를 압박하게 되고 이로 인해 다양한 임상 증상을 유발할 수 있다. 특히 경막 내에 위치한 분리추간판의 경우, 경막절개술을 통해서만 병변을 식별할 수 있다. 따라서 수술 전에 분리추간판의 정확한 위치와 범위를 파악하는 것은 수술 계획을 세우는 데 중요하다. 자기공명영상에서 분리추간판은 초기에는 모체 추간판과 유사한 신호강도를 보이지만 이후 독립적인 퇴행 변화를 거치며 신호강도가 달라질 수 있다. 또한 대부분의 분리추간판 조각은 염증 반응의 결과로 인해 인접한 혈관발생과 육아조직의 형성 정도에 따라 다양한 정도의 주변 조영증강을 보일 수 있다. 이종설에서는 분리추간판의 다양한 영상 소견과 위치를 소개하여 환자에게 정확한 진단과 적절한 치료 방향을 제시하는 데 도움이 되고자 한다.

• 한국가금학회지
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• 제35권4호
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• pp.367-373
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• 2009

본 연구는 유기 산란계의 산란기 영양적 특성을 구명하고 산란기 성장기별 에너지와 단백질의 적정 수준을 설정하기 위해 실시하였다. 시험에 사용된 공시축은 산란계(Hy-Line) 360수이었으며, 시험 전 기간 평사에서 사육하였다. 시험 사료는 옥수수와 대두박 위주의 유기 사료를 이용하였다. 시험구 배치는 에너지 수준 3수준(2,800, 3,080, 3,360 kcal/kg), 단백질 수준 2수준(16, 18%)인 6처리 4반복 반복당 15수씩 총 360수를 공시하였다. 시험 사료는 산란 기간 동안 자유 채식시켰고 물은 자유로이 마시도록 하였으며, 점등은 자연 일조를 포함하여 14시간을 넘지 않도록 하였으며, 횃대와 산란 상자를 만들어 주었다. 그 외의 사양 관리는 유기 양계 규정에 맞도록 준수하였다. 산란기 생산성은 에너지 수준을 달리했을 때 산란율, 난중 및 산란량에서 NRC 에너지 수순과 비슷한 2,800 kcal/kg 수준이 3,080 및 3,360 kcal/kg 수준에 비해 시험 전 기간에 걸쳐 유의적으로 높은 생산성을 보였다(P< 0.05). 계란의 난각 강도는 에너지와 단백질 수준간 통계적인 유의차는 없었으나, 난각 두께는 50, 70주령에 에너지 수준이 높은 3,360 kcal/kg에서 유의적으로 두꺼웠다. 혈액생화학은 Total Cholesterol의 수치가 에너지 수준의 증가와 함께 유의적으로 높아졌다(P<0.05). 본 연구의 결과를 종합해 보면, 유기 산란계의 산란기 적정 에너지와 단백질 수준은 ME 2,800 kcal/kg, CP 16%에서 산란 생산성 및 계란의 품질을 높게 유지하였다.

• 자원환경지질
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• 제34권4호
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• pp.395-415
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• 2001

충남 서부 신곡 및 계월 두 초염기성 암체가 선캠브리아기 경기 편마암 복합체내에서 격리된 안구상 암체로서 산출되고 있다. 이 암체들은 이 지역의 우세한 구조선 반향인 NINE 방향과 평행하게 수백 m 신장되어 분포한다. 이 암석들은 완전히 또는 부분적으로 사문암화 및 활석화 되었고 잔쇄 반상조직이 두드러지며 등립질-모자이크조직 및 원생입상조직을 보이기도 한다. 광물 조성상 듀나이트 또는 하즈버자이트로 변질 및 변성정도에 따른 차이를 보이기도 하지만 높은 포스테라이트 조성의 감람석($Fo_{0.88-0.93}$), 엔스테타이트 조성의 사방휘석($En_{0.93-0.97}$), 트래모라이트질에서 체마카이트질의 각섬석 및 투각섬석을 주로 포함하고 첨정석, 사문석, 녹리석, 방해석, 자철석, 금운모, 활석등을 포함하기도 한다. 이런 특징들은 주변의 각섬석, 흑운모, 사장석, 알칼리 장석, 석영을 포함하는 편마암 복합체와 뚜렸이 구분이 된다. 지화학적으로 이 암석들은 높은 마그네슘비(Mg>90.38) 및 전이 원소(Ni=595-2480, Cr=1010-4400, Co=36-120 ppm) 함량과 낮은 알칼리 원소($Na_{2}O$<0.3, $K_{2}O$<0.11, $Al_{2}O_3$<2.95 wt%) 함량 및 결핍된 비호정성 원소들의 빈도가 특징적이다. 이런 특징들은 주변암이 보이는 것들(Mg<83.69, $Na_{2}O$ = 1.02-3.42 wt%, $K_{2}O$=0.67-5.65 wt%, $Al_{2}O_3$ = 9.15-16.86 wt%, Ni< 435 ppm, Cr < 1440 ppm, Co < 59 ppm, 부화된 비호정 성원소함량)과 차이를 보인다. 이 암체들의 암석학적, 지화학적, 광물학적 결과들은 충남 인접지역 및 전세계의 지구조적으로 노출된 알파인형의 초염기성암과 유사하다. 계산된 지질온도는 이 암석이 상부녹색편암상에서 백립암상에 해당되는 온도범위에서 변성작용을 받았음을 암시한다.

• 대한간호학회지
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• 제24권4호
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• pp.623-634
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• 1994

Although the average menopausal age has not changed, women's life span has increased. Today's women live longer after their menopause than those in the past, and this calls for attention in both nursing and medical fields. Many studies have revealed how women reacted to menopause and suffered from it. But they did not discriminate the menopausal meaning and effects from the climacteric phenomena. So, this author tried to clarify what menopause itself meant to the climacteric women, by means of grounded theory methodology. The interviewees were 21 women, whose ages were between 46 and 60 years. They were selected by theoretical sampling technique, and the author tried to include all levels of important variables such as age, educational background, religion and job. Data were collected by the author through in -depth interviews and observations in July, 1994. The interviews were mostly done in the homes of the subjects, or in some cases at the author's office or in a hospital. Interviews took from 30 minutes to 2 hours. Interviews were tape recorded and transcribed later by a research assistant. Data were analyzed as gathered, by the constant comparative method proposed by Strauss and Corbin. Eleven concepts were discovered from the data, and they were grouped under six higher order categories. These six categories were "to give menopause a meaning", "to experience value change", "to have self-help strategies", "to have no strategies", "to live a life worth living", "to have a sense of powerlessness" Among these "to experionce value change" was . selected as the core category. Five major categories were systematically integrated around the core category. Women's adaptation to menopause was defined as proceeding as follows : Most women felt relief and sorrow at the same time when they faced menopause, and some only sorrow or agony. Then, they consulted with others about menopausal symptoms, or tried to think of them by themselves. Finally, they gave menopause a meaning, which was that menopause and its symptoms were natural phenomena. But menopause made women reflect on them-selves and their past lives. As they reflected on themselves, their value on life began to change. As their value changed, some women seeked self help strategies. Those self help strategies were what they had learned from collegues, professionals or mass media. The quality of their lives depended on whether they practiced self help strategies or not. Three types of lives were found. Twelve women enjoyed a life worth living, and practiced the self help strategies, because they accepted menopause a chance to change. They were characterized by a high educational level, having a professional job and a sincere faith in God. Seven women were living as usual, because they did not have the necessity to change. They were high school graduates and house wives. Two women recognized menopause a chance to change, but they did not try self help strategies. Their characteristic was low educational level. Those who did not try self help strategies complained of powerlessness to varying degrees. The educational background, full-time jobs and faith helped women adapt to menopause positively. But social support was not helpful to women's adaptation to menepause. Three hypotheses were derived from the analysis. (1) The higher the educational level, the more theneed to change. (2) Women with higher educational background will practice self help strategies more than those with lower edcational background. (3) The more women practice self help strategies, the worthier lives they will live. Suggestions for further studies are as follows. (1) Studies to test hypotheses are needed. (2) A study to find the relationship between the degree of practicing self help strategies and locus of control. (3) Spiritual approaches would better be applied to help menopausal women. (4) Education through mass media should be given mere frequently.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제20회 춘계학술대회 논문집
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• pp.91-93
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• 2003

A comprehensive numerical study is carried out to investigate for the understanding of the flow evolution and flame development in a supersonic combustor with normal injection of ncumally injecting hydrogen in airsupersonic flows. The formulation treats the complete conservation equations of mass, momentum, energy, and species concentration for a multi-component chemically reacting system. For the numerical simulation of supersonic combustion, multi-species Navier-Stokes equations and detailed chemistry of H2-Air is considered. It also accommodates a finite-rate chemical kinetics mechanism of hydrogen-air combustion GRI-Mech. 2.11[1], which consists of nine species and twenty-five reaction steps. Turbulence closure is achieved by means of a k-two-equation model (2). The governing equations are spatially discretized using a finite-volume approach, and temporally integrated by means of a second-order accurate implicit scheme (3-5).The supersonic combustor consists of a flat channel of 10 cm height and a fuel-injection slit of 0.1 cm width located at 10 cm downstream of the inlet. A cavity of 5 cm height and 20 cm width is installed at 15 cm downstream of the injection slit. A total of 936160 grids are used for the main-combustor flow passage, and 159161 grids for the cavity. The grids are clustered in the flow direction near the fuel injector and cavity, as well as in the vertical direction near the bottom wall. The no-slip and adiabatic conditions are assumed throughout the entire wall boundary. As a specific example, the inflow Mach number is assumed to be 3, and the temperature and pressure are 600 K and 0.1 MPa, respectively. Gaseous hydrogen at a temperature of 151.5 K is injected normal to the wall from a choked injector.A series of calculations were carried out by varying the fuel injection pressure from 0.5 to 1.5MPa. This amounts to changing the fuel mass flow rate or the overall equivalence ratio for different operating regimes. Figure 1 shows the instantaneous temperature fields in the supersonic combustor at four different conditions. The dark blue region represents the hot burned gases. At the fuel injection pressure of 0.5 MPa, the flame is stably anchored, but the flow field exhibits a high-amplitude oscillation. At the fuel injection pressure of 1.0 MPa, the Mach reflection occurs ahead of the injector. The interaction between the incoming air and the injection flow becomes much more complex, and the fuel/air mixing is strongly enhanced. The Mach reflection oscillates and results in a strong fluctuation in the combustor wall pressure. At the fuel injection pressure of 1.5MPa, the flow inside the combustor becomes nearly choked and the Mach reflection is displaced forward. The leading shock wave moves slowly toward the inlet, and eventually causes the combustor-upstart due to the thermal choking. The cavity appears to play a secondary role in driving the flow unsteadiness, in spite of its influence on the fuel/air mixing and flame evolution. Further investigation is necessary on this issue. The present study features detailed resolution of the flow and flame dynamics in the combustor, which was not typically available in most of the previous works. In particular, the oscillatory flow characteristics are captured at a scale sufficient to identify the underlying physical mechanisms. Much of the flow unsteadiness is not related to the cavity, but rather to the intrinsic unsteadiness in the flowfield, as also shown experimentally by Ben-Yakar et al. [6], The interactions between the unsteady flow and flame evolution may cause a large excursion of flow oscillation. The work appears to be the first of its kind in the numerical study of combustion oscillations in a supersonic combustor, although a similar phenomenon was previously reported experimentally. A more comprehensive discussion will be given in the final paper presented at the colloquium.