http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
박재용,유진식,황승민,임민규,오영규,김용대,한석영,맹주성 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-
An active micro-mixer, which is composed of an oscillating micro-stirrer in the micro-channel to provide effective mixing was optimized. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight micro-channel and micro-channel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interaction after the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models were compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced' and stabilized. Therefore, an approximate optimization of an active micro-mixer with an oscillating stirrer was performed using Kriging method with OLHD (Optimal Latin Hypercube Design) in order to determine the optimal design variables. The design parameters were established as the frequency, the length and the angle of the stirrer. The optimal values were obtained as 1.5754, 0.803D and ±45°, respectively. It was found that the mixing index of the optimal design increased by 83.36% compared with that of the original design.
( Seung Gyu Han ),( Shin Wook Kang ),( Youn Kyung Kee ),( Chang Yun Yoon ),( Eunyoung Lee ),( Young Su Joo ),( In Mee Han ),( Tae Hyun Yoo ),( Jung Tak Park ) 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1
Background: Reduced residual renal function (RRF) is associated with left ventricular (LV) hypertrophy as well as all-cause and cardiovascular (CV) mortality in patients with ESRD. However, the serial changes in echocardiographic fi ndings according to the decline rates of RRF have not been fully elucidated in incident peritoneal dialysis (PD) patients. Methods: Totally 81 patients, who started PD between 2005 and 2012 at YUHS and underwent baseline and follow-up echocardiography within the fi rst year of PD, were recruited. Based on the 1-year median RRF decline slope, patients were divided into ‘faster’ and ‘slower’ groups. Time-dependent serial changes in echocardiographic parameters were compared between the two groups by linear mixed model (LMM). Results: Baseline RRF and echocardiographic parameters were comparable between the two groups. The decline rate of RRF was an independent factor for the changes in LV end diastolic volume index (LVEDVI) (P=0.019), left atrial volume index (LAVI) (P=0.006), and LV mass index (LVMI) (P=0.005). The LMM further confirmed that LVEDVI, LAVI, and LVMI were signifi cantly more improved in the ‘slower’ group than those in the ‘faster’ group (P=0.047, P=0.048, and P=0.001, respectively). Compared to the ‘faster’ group, composite CV outcome (P=0.098), technique failure (P=0.006), and PD peritonitis (P=0.064) occurred less frequently in ‘slower’ group. Multivariate Cox regression analysis revealed that ‘faster’ RRF decline was a signifi cant risk factor for each clinical outcome [composite CV outcome, HR=4.82, 95% CI=1.15-20.22, P=0.03; technique failure, HR=4.44, 95% CI=1.15-17.18, P=0.03; PD peritonitis, HR=7.37, 95% CI=1.43-38.04, P=0.02]. Conclusion: Cardiac performance was signifi cantly improved in incident PD patients with slow RRF decline, which might partly contribute to better clinical outcomes in this group. Therefore, preservation of RRF may be benefi cial for the clinical outcome by improving cardiac performance.
김주환(Kim Joo-Han),김민규(Kim Min-Gyu),김은주(Kim Eun-Joo),신의진(Shin Yee-Jin) 한국청소년정책연구원 2008 한국청소년연구 Vol.19 No.1
본 연구의 목적은 온라인 게임 중독의 개념적 구인과 측정 모형을 근거로 신뢰도가 높은 검사 도구를 개발하고 이의 타당성을 검증해보는 데 있다. 우선 문항 반응의 편파성, 문항의 내적 일관성, 문항의 일차원성을 검토하여 19개의 문항으로 이루어진 온라인 게임 중독 검사도구를 개발한 후, 중학생 199명과 초등학생 1,422명을 대상으로 확인적 요인분석을 통해 타당도와 신뢰도를 검증하였다. 나아가 온라인 게임 중독 검사도구의 일반화 검증을 위해 수렴타당도와 판별타당도를 확인하였으며, 적절한 수준의 외적 타당도를 가지는 검사도구임이 검증되었다. 본 연구결과를 통하여 온라인 게임중독은 하나의 현상이라기보다는 이러한 다양한 유형이 복합적으로 얽혀서 이루어진 다면체적인 현상임이 확인되었다. 본 연구에서 개발한 온라인 게임 중독 검사 도구는 지금까지 개발되어 사용되고 있는 검사도구와는 구별되는 다차원적인 문항으로 구성되어 있어 우리나라 청소년들의 온라인 게임 중독 실태를 파악하고 보다 효과적인 대응책을 마련하는데 많은 도움이 줄 수 있을 것이다. The main purpose of the present study is to develop a measure of problematic online game use by identifying underlying factors and testing external validities of the resultant scale. The authors tested the scale with two age groups: 5<SUP>th</SUP> and 8<SUP>th</SUP> graders. Through a series of confirmatory factor analyses, the present study confirmed that the problematic online game use scale produced reliable and consistent factorial structures across the independent samples. The results supported the convergent validity of the scale: problematic online game use showed significant correlations with satisfaction with daily life, academic self-efficacy, psychosocial problems, mental disorders and time spent playing online games. The results also supported the discriminant validity, in that the problematic online game use scale did not redundantly measure any of the individual difference constructs and was statistically distinguishable from the closely correlated constructs.
( In Mee Han ),( Dong Ho Shin ),( Youn Kyung Kee ),( Chang Yun Yoon ),( Eunyoung Lee ),( Young Su Joo ),( Seung Gyu Han ),( Hyung Jung Oh ),( Jung Tak Park ),( Seung Hyeok Han ),( Shin Wook Kang ),( T 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1
Background: Delta Neutrophil Index (DNI) indicates the fraction of circulating immature granulocytes, which is known to increase in infectious and/or septic conditions. However, the relationship between DNI and mortality in septic acute kidney injury (AKI) patients is not yet fully elucidated. Therefore, we assessed whether DNI is associated with mortality in septic AKI patients requiring continuous renal replacement therapy (CRRT). Methods: We retrospectively enrolled 285 patients with septic AKI who were treated with CRRT at Yonsei University Health System between August 2009 and September 2012. The patients were dichotomized into high and low DNI groups based on the cutoff value from receiver operating characteristics of DNI values at the time of CRRT initiation. Log-rank test and Cox proportional hazards analysis were conducted to evaluate the effect of DNI as a prognostic factor for 28-day all-cause mortality. Results: The mean age of the enrolled patients was 61.0 ± 14.7 years and 180 patients (63.2%) were male. The high DNI group (DNI > 5.6%) was composed of 149 patients (52.3%). During the study period, 192 patients (67.1%) died. Mortality rate during the 28-days was significantly increased in the high DNI group compared to low DNI group (79.9% vs. 53.3%, P < 0.01, log rank test p Conclusions: This study demonstrates that DNI at CRRT initiation could be an useful predictor for mortality in septic AKI patients requiring CRRT.
( Young Su Joo ),( Chan Ho Kim ),( Youn Kyung Kee ),( Chang Yun Yoon ),( Eun Young Lee ),( In Mee Han ),( Seung Gyu Han ),( Jung Tak Park ),( Seung Hyek Han ),( Tae Hyun Yoo ),( Shin Wook Kang ),( Hyu 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1
Background: Mean platelet volume (MPV) is suggested as an index of infi ammation and disease activity in addition to refi ecting the effi cacy of anti-infi ammatory treatment in chronic infi ammatory disorder patients. However, the prognostic value of MPV on mortality remains unclear in patients with severe sepsis. Methods: We prospectively enrolled 345 patients admitted to the emergency department (ED) who received standardized resuscitation for severe sepsis and/or septic shock between Nov. 2007 and Dec. 2011. The change in MPV between hospital admission and 72 hours after treatment (ΔMPV72h-adm) was evaluated as a prognostic factor for 28- day mortality. Linear mixed model and Cox proportional hazards analysis were used. Results: The mean age of the enrolled patients was 64.2±15.7 years, 169 (49.0%) of them were males. Thirty-fi ve (10.1%) patients died within 28 days after ED admission. During the fi rst 72 hrs of ED admission, MPV signifi cantly increased in both non-survivors (P = 0.001) and survivors (P < 0.001) compared to baseline. ΔMPV72h-adm was signifi cantly higher, indicating an increase in MPV during the fi rst 72 hours, in non-survivors compared to survivors (P = 0.003). However, the change in the number of platelets over the fi rst 72 hours did not differ signifi cantly between the two groups (P = 0.360). Multivariate analysis revealed that ΔMPV72h-adm was an independent predictor of 28-day mortality, even after adjusting for age, sex, body mass index, Sequential Organ Failure Assessment score, renal replacement therapy, platelet count, C-reactive protein level, albumin level, and lactate level (hazard ratio, 1.44; 95% confi dence interval, 1.01-2.06; P = 0.044). Conclusions: An increase in MPV during the fi rst 72 hours of hospitalization could be an independent risk factor for adverse clinical outcomes in severe sepsis.