• 한국안전학회지
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• 제37권2호
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• pp.76-87
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• 2022

Lithium-ion batteries (LIBs) have attracted much interest for their high energy density (>150 mAh/g), high capacity, low self-discharge rate, and high coulombic efficiency. However, with the successful commercialization of LIBs, fire and explosion incidents are likely to increase. The thermal runaway is known as the major factor in battery-related accidents that can lead to a series of critical conditions. Considering this, recent studies have shown an increased interest in countering the safety issues associated with LIBs. Although safety standards for LIB use have recently been formulated, little attention has been paid to the safety around the manufacturing process for battery products. The present study introduces a risk assessment method suitable for assessing the safety of the LIB-manufacturing process. In the assessment method, a compensation parameter (Z-factor) is employed to correctly evaluate the process's safety on the basis of the type of material (e.g., metal anode, liquid electrolyte, solid-state electrolytes) utilized in a cell. The proposed method has been applied to an 18650 cell-manufacturing process, and three sub-processes have been identified as possibly vulnerable parts (risk index: >4). This study offers some crucial insights into the establishment of safety standards for battery-manufacturing processes.

• Journal of Chest Surgery
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• 제57권1호
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• pp.70-78
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• 2024

Background: This study investigated the outcomes of biventricular repair using right ventricle to pulmonary artery (RV-PA) conduit placement in patients aged <1 year. Methods: Patients aged <1 year who underwent biventricular repair using an RV-PA conduit between 2011 and 2020 were included in this study. The outcomes of interest were death from any cause, conduit reintervention, and conduit dysfunction (peak velocity of ≥3.5 m/sec or moderate or severe regurgitation). Results: In total, 141 patients were enrolled. The median age at initial conduit implantation was 6 months. The median conduit diameter z-score was 1.3. The overall 5-year survival rate was 89.6%. In the multivariable analysis, younger age (p=0.006) and longer cardiopulmonary bypass time (p=0.001) were risk factors for overall mortality. During follow-up, 61 patients required conduit reintervention, and conduit dysfunction occurred in 68 patients. The 5-year freedom from conduit reintervention and dysfunction rates were 52.9% and 45.9%, respectively. In the multivariable analysis, a smaller conduit z-score (p<0.001) was a shared risk factor for both conduit reintervention and dysfunction. Analysis of variance demonstrated a nonlinear relationship between the conduit z-score and conduit reintervention or dysfunction. The hazard ratio was lowest in patients with a conduit z-score of 1.3 for reintervention and a conduit z-score of 1.4 for dysfunction. Conclusion: RV-PA conduit placement can be safely performed in infants. A significant number of patients required conduit reintervention and had conduit dysfunction. A slightly oversized conduit with a z-score of 1.3 may reduce the risk of conduit reintervention or dysfunction.

• 천문학회보
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• 제38권2호
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• pp.69.2-69.2
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• 2013

A galaxy cluster is an important laboratory to study the large scale structure in the Universe and the galaxy evolution. In order to identify candidate galaxy clusters at z~1, we have used deep and wide optical-NIR datasets based on IMS, UKIDSS DXS and CFHTLS wide covering ${\sim}20deg^2$ in the SA22 field. We measure the angular two-point correlation function of the candidate clusters and investigate the star formation activity of the member galaxies. Based on bias factor and halo mass function, candidate clusters have the average halo mass of > $10^{14}h^{-1}M_{\odot}$. At z~1, the star formation rate of cluster galaxies is similar to that of field galaxies, which indicates the environmental quenching is not so significant at z~1 as the local Universe.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.172-175
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• 2007

The Performance of a PEMFC stack is strongly dependent on the uniform reactants distribution on MEA. The uniform distribution can be achieved by flow-field pattern and manifold design optimized to satisfy operating conditions. This paper investigates uniform reactants distribution in channels by changing manifold shape and inlet mass flow rate. Typical U and Z shape and modified U and Z shape manifolds with buffer zone were designed. To check the uniform reactants distribution, standard deviation of mass flow rate was compared. The numerical results show that the inlet mass flow rate, inlet shape, and manifolds shape are critical factor for uniform distribution.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.131-136
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• 1996

An analytic nodal expansion method has been derived for the multigroup neutron diffusion equation in 2-D cylindrical(R-Z) coordinate. In this method we used the second order Legendre polynomials for source, and transverse leakage, and then the diffusion eqaution was solved analytically. This formalism has been applied to 2-D LWR model. $textsc{k}$$_{eff}$, power distribution, and computing time have been compared with those of ADEP code(finite difference method). The benchmark showed that the analytic nodal expansion method in R-Z coordinate has good accuracy and quite faster than the finite difference method. This is another merit of using R-Z coordinate in that the transverse integration over surfaces is better than the linear integration over length. This makes the discontinuity factor useless.s.

• 생약학회지
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• 제50권2호
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• pp.86-95
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• 2019

In the present study, the effect of Z. jujuba Miller var. inermis Rehder extracts on the secretion of atopic dermatitis (AD)-related cytokines and hyaluronidase activity was investigated. We prepared four fractions, butylene glycol (JB), ethanol (JE), and water (JW), with Z. jujuba Miller var. inermis extracts. JW significantly reduced the secretion of interleukin-8 and JE reduced the secretion of tumor necrosis factor-alpha in human keratinocyte HaCaT cells. Also, hyaluronidase activity was measured by enzyme assay and the fractions inhibited the activity in a dose-dependent manner. In addition, the human dermal fibroblast, HDF-n cells were treated with the extracts and antioxidant activities were measured. The results showed that the extracts increased the free radical scavenging activity and the superoxide dismutase activity. Taken together, Z. jujuba Miller var. inermis extracts reduced the secretion of AD-related cytokines and inhibited the hyaluronidase. In addition, the extracts showed antioxidant activity.

• 생명과학회지
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• 제31권3호
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• pp.338-345
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• 2021

고장초는 오랫동안 식용 및 의약 목적으로 차를 만드는 데 사용되어 왔다. 그러나 고장초를 고부가가치 식용 재료로 사용하는 연구는 불충분하다. 이전 연구에서 우리는 tricin이 고장초의 주요 화합물임을 확인했다. 본 연구에서는 고장초 추출물의 HepG2 세포 보호 효과를 조사하였다. 고장초 추출물 또는 tricin의 HepG2 세포에 대한 독성 실험 결과, 사용한 모든 농도에서 고장초 추출물 또는 tricin에 대한 독성은 나타나지 않았다. 또한 tert-butyl hydroperoxide (t-BHP)에 의해 감소된 세포 생존율은 고장초 추출물(100 ㎍/ml에서 69.23%) 또는 tricin (100 ng/ml에서 74.47%)에 의해 증가되었다. 또한 고장초 추출물(250 ㎍/ml) 또는 tricin (250 ng/ml)은 산화적 손상에 의한 활성 산소종(ROS) 생성을 효과적으로 억제했다. 또한 항산화 효소로 알려진 superoxide dismutase 1(SOD1), catalase, heme oxygenase-1 (HO-1), nuclear factor erythroid-related factor 2 (Nrf2)의 단백질 발현은 고장초 추출물(100 ㎍/ml에서 2.1, 1.6, 1.7, 1.5배) 또는 tricin (250 ng/ml에서 2.6, 1.8, 2.2, 2.0배) 처리로 증가했으며, 이는 고장초 추출물의 HepG2 세포 보호 효과는 tricin의 활성과 관련이 있다는 것을 시사한다. 종합하면 고장초는 간 기능개선 관련 기능성 식품 소재로 개발이 가능할 것으로 기대된다.

• 한국산림과학회지
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• 제70권1호
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• pp.7-16
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• 1985

임목(林木)의 주체성인(主體成因)인 수간(樹幹)에 대한 각종(各種) 성장인자간(成長因子間)의 정준상관(正準相關)과 그의 관계적(關係的) 배경(背景) 및 수간(樹幹)의 총합적(總合的)인 변동분석(變動分析)에 의(依)한 수간적(樹幹的) 특징(特徵)을 파악(把握)함에 있어, 그의 최적기법(最適技法)을 탐색(探索)하기 위한 시도(試圖)로서 일본(日本)잎갈나무(Larix leptolepis)에 주성분(主成分) 및 정준상관분석법(正準相關分析法)을 도입적용(導入適用)하고, 얻어진 결과(結果)를 다음과 같이 요약(要約)한다. 1) 정형수(正形數)($x_8$)를 제외(除外)한 모든 성장인자(成長因子) 즉(卽), 수고(樹高)($x_1$), 지하고(枝下高)($x_2$), 망고(望高)($x_3$), 흉고직경(胸高直徑)($x_4$), 중앙직경(中央直徑)($x_5$), 수관폭(樹冠幅)($x_6$) 및 간재적(幹材積)($x_7$) 등(等)의 각(各) 인자간(因子間)에 강약간(強弱間)의 상관(相關)이 있으며, 특(特)히 흉고직경(胸高直徑), 수고(樹高) 및 중앙직경(中央直徑) 등(等)은 간재적(幹材積)과 고도(高度)의 상관(相關)이 있다(표(表) l 참조(參照)). 2) (1) 상장성장인자(上長成長因子)인 수고(樹高), 지하고(枝下高) 및 망고(望高) 등(等)의 합성변량(合成變量)과 간재적간(幹材積間), (2) 비대성장인자(肥大成長因子)인 흉고직경(胸高直徑), 중앙직경(中央直徑) 및 수관폭(樹冠幅) 등(等)의 합성변량(合成變量)과 간재적간(幹材積間), (3) 상장(上長) 및 비대성장인자(肥大成長因子)를 총망라(總網羅)한 6개인자(個因子)의 합성변량(合成變量)과 간재적간(幹材積間)의 정준상관계수(正準相關係數)와 정준변량(正準變量)이 각각(各各) $${(1)\;{\gamma}_{u1,v1}=0.82980^{**},\;\{u_1=1.00000x_7\\v_1=1.08323x_1-0.04299x_2-0.07080x_3}\\{(2)\;{\gamma}_{u1,v1}=0.98198^{**},\;\{u_1=1.00000x_7\\v_1=0.86433x_4+0.11996x_5+0.02917x_6}\\{(3)\;{\gamma}_{u1,v1}=0.98700^{**},\;\{u_1=1.00000x_7\\v1=0.12948x_1+0.00291x_2+0.03076x_3+0.76707x_4+0.09107x_5+0.02576x_6}$$ 등(等)과 같이 되어, 어느 경우(境遇)에서도 고도(高度)의 정준상관(正準相關)을 가지며, (1)의 경우(境遇)에는 수고(樹高)가, (2)의 경우(境遇)에는 흉고직경(胸高直徑)이, (3)의 경우(境遇)에는 흉고직경(胸高直徑)과 수고(樹高)가 각각(各各)의 정준상관(正準相關)에 절대적인 기여(寄與)를 하는 것으로서, 각종(各種) 질적성장(質的成長)의 총합특성(總合特性)은 이들 인자(因子)의 막강한 영향력(影響力)에 의해서 형성(形成)되며, 특(特)히 (3)의 경우에서 간재적(幹材積)과의 정준상관(正準相關)에 미치는 흉고직경(胸高直徑)의 영향력(影響力)은 기타(其他)의 인자(因子)에 비(比)하여 판이(判異)하게 큰 것으로 밝혀지고 있다(표(表) 2 참조(參照)). 3) 상장성장인자(上長成長因子)인 수고(樹高), 지하고(枝下高) 및 망고(望高) 등(等)의 합성변량(合成變量)과 비대성장인자(肥大成長因子)인 흉고직경(胸高直徑), 중앙직경(中央直徑) 및 수관폭(樹冠幅) 등(等)의 합성변량간(合成變量間)의 정준상관계수(正準相關係數)와 정준변량(正準變量)이 $${\gamma}_{u1,v1}=0.78556^{**},\;\{u_1=1.20569x_1-0.04444x_2-0.21696x_3\\v_1=1.09571x_4-0.14076z_5+0.05285z_6$$와 같이 됨에 따라, 각종 상장성장인자(上長成長因子)와 비대성장인자간(肥大成長因子間)의 고도(高度)의 정준상관(正準相關)에 있어 수고(樹高)와 흉고직경(胸高直徑)만의 기여도(寄與度)가 극(極)히 현저한 것으로서, 상장성장(上長成長)의 총합특성(總合特性)은 수고(樹高)에 의해서, 비대성장(肥大成長)의 총합특성(總合特性)은 흉고직경(胸高直徑)에 의해서 각각(各各) 형성(形成)된다는 사실(事實)이 확인(確認)된 것이다. 따라서 양인자(兩因子)에 대한 간재적계측(幹材積計測)에 있어서의 필수유력인(必須有力因子)로서의 과학성(科學性)이 입증(立證)된 것이라 생각한다(표(表) 2 참조(參照)). 4) 수간(樹幹)의 8개성장인자(個成長因子) 즉(卽), 8차원(次元)의 정보(情報)(특성치(特性値))를 설정(設定)된 유효목표(有效目標) 85%에 따라 3차원(次元)으로 간략화(簡約化)된 총합특성치(總合特性値) 즉(卽), 제(第) 1 ~ 제(第) 3 주성분(主成分)은 다음과 같다. 제(第) 1 주성분(主成分)($Z_1$); $Z_1=0.40192x_1+0.23693x_2+0.37047x_3+0.41745x_4+0.41629x_5+0.33454x_60.42798x_7+0.04923x_8$ 제(第) 2 주성분(主成分)($Z_2$) ; $z_2=-0.09306x_1-0.34707x_2+0.08372x_3-0.03239x_4+0.11152x_5+0.00012x_6+0.02407x_7+0.92185x_8$ 제(第) 3 주성분(主成分)($Z_3$) ; $Z_3=0.19832x_1+0.68210x_2+0.35824x_3-0.22522x_4-0.20876x_5-0.42373x_6-0.15055x_7+0.26562x_8$ 제(第) 1 주성분(主成分)($Z_1$)은 기여율(寄與率)이 63.26%나 되는 매우 높은 정보흡수력(情報吸收力)을 가진 "크기의 인자(因子)(size factor)"로서, 그의 주성분득점(主成分得點)(principal component score)은 인자부하량(因子負荷量)이 매우 높은 간재적(幹材積), 흉고직경(胸高直徑), 중앙직경(中央直徑) 및 수고(樹高) 등(等)에 의해써 결정(決定)되며, 제(第) 2 주성분(主成分)($Z_2$)은 입체적(立體的) 형상(形狀)의 지표(指標) 즉(卽), 수간(樹幹)의 입체적(立體的) 상사성(相似性)과 완구도(完溝度)를 나타내주는 "형상(形狀)의 인자(因子)(shape factor)"로서, 그의 score는 정형수(正形數)의 절대적(絶對的)인 영향력(影響力)에 의(依)해서 형성(形成)되며, 제(第) 3 주성분(主成分)($Z_3$)은 상장성장(上長成長)과 비대성장(肥大成長)과의 역관계(逆關係)의 현상(現象) 즉(卽), 수간(樹幹)의 세장(細長)(또는 굵고 짧음)의 정도를 표시(表示)하는 성장형상(成長形狀)의 지표(指標)로서, 이는 제(第) 2의 "형상(形狀)의 인자(因子)"가 된다. 이상(以上) 3개주성분(個主成分)은 그의 누적기여율(累積寄與率)이 88.36%로서 만족스러운 정보흡수역량(情報吸收力量)을 지니고 있다(표(表) 3 참조(參照)). 5) 본(本) 연구(硏究)에 적용(適用)된 주성분(主成分) 및 정준(正準) 상관분석법(相關分析法)은 적극적(積極的)인 이용개발(利用開發)에 따라서는 삼림계측(森林計測)(임목성장(林木成長)), 지위판정분류(地位判定分類), 삼림(森林) 및 임산업(林産業)의 경영진단(經營診斷), 임산가공(林産加工)(품(品))의 생산관리(生産管理) 및 기지(其地) 총합특성치(總合特性値)의 산정(算定)을 필요(必要)로 하는 분야(分野)에 많은 기여(寄與)가 있을 것으로 사료(思料)된다.

• 전기학회논문지
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• 제62권8호
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• pp.1163-1168
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• 2013

The maximum allowable value of loop impedance($Z_s$) to secure the operation of overcurrent protective devices and the safety for indirect contact is a very important in TN-C-S system. The loop impedance is divided into inner loop impedance which consumer can adjust and external loop impedance($Z_e$) which only electric operator can adjust. Thus, an external loop impedance which limits to less than a certain value is a very important factor for human body protection against electric shock in TN-C-S system. The concept of loop impedance($Z_s$) is recently introduced to the domestic, the study about external loop impedance is yet insufficient. However, the study about the reference impedance as specified by the IEC 60725 standard to improve the quality and reliability of the power supply is being made. In this paper, reference value of external loop impedance($Z_e$) to meet domestic environment will be proposed by the nationwide measurement and statistical analysis.

• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.666-674
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• 2009

An electrochemical bioreactor (ECB) composed of a cathode compartment and an air anode was used in this study to characterize the ethanol fermentation of Zymomonas mobilis. The cathode and air anode were constructed of modified graphite felt with neutral red (NR) and a modified porous carbon plate with cellulose acetate and porous ceramic membrane, respectively. The air anode operates as a catalyst to generate protons and electrons from water. The growth and ethanol production of Z. mobilis were 50% higher in the ECB than were observed under anoxic nitrogen conditions. Ethanol production by growing cells and the crude enzyme of Z. mobilis were significantly lower under aerobic conditions than under other conditions. The growing cells and crude enzyme of Z. mobilis did not catalyze ethanol production from pyruvate and acetaldehyde. The membrane fraction of crude enzyme catalyzed ethanol production from glucose, but the soluble fraction did not. NADH was oxidized to $NAD^+$in association with $H_2O_2$reduction, via the catalysis of crude enzyme. Our results suggested that NADH/$NAD^+$balance may be a critical factor for ethanol production from glucose in the metabolism of Z. mobilis, and that the metabolic activity of both growing cells and crude enzyme for ethanol fermentation may be induced in the presence of glucose.