Dehydrogenative Polymerization of Hydrosilanes to Silicon Polymers

김명희,이준,모수용,김종현,우희권,Kim, Myoung-Hee,Lee, Jun,Mo, Soo-Yong,Kim, Jong-Hyun,Woo, Hee-Gweon The Basic Science Institute Chosun University 2010 조선자연과학논문집 Vol.3 No.2

Hydrosilanes possessing reactive Si-H bond are used in synthesizing various types of polysilanes by dehydrocoupling under the influence of various organometallic promoters. Catalytic Si-Si/Si-O coupling of hydrosilanes with hydrosilanes, alcohols, and lactones to silicon-based polymers are described in this article as selective examples of our recent research developments. These silicon-containing polymers can be used as a precursor to prepare useful functional materials for fabricating electronic devices.

Dehydrocoupling of Bis(silyl)alkylbenzenes to Network Polysilanes, Catalyzed by Group 4 Metallocene Combination

김명희,이준,무수용,김종현,고영춘,우희권,Kim, Myoung-Hee,Lee, Jun,Moo, Soo-Yong,Kim, Jong-Hyun,Ko, Young Chun,Woo, Hee-Gweon The Basic Science Institute Chosun University 2010 조선자연과학논문집 Vol.3 No.1

Bis(silyl)alkylbenzenes such as bis(1-sila-sec-butyl)benzene (1) and 2-phenyl-1,3-disilapropane (2) were synthesized in high yields by the reduction of the corresponding chlorosilanes with $LiAlH_4$ in diethyl ether. The dehydrocoupling of 1 and 2 was performed using group IV metallocene complexes generated in situ from $Cp_2MCl_2$/Red-Al and $Cp_2MCl_2$/n-BuLi (M = Ti, Hf), producing two phases of polymers. The TGA residue yields of the insoluble polymers were in the range of 64-74%. The molecular weights of the soluble polymers produced ranged from 700 to 5000 ($M_w$ vs polystyrene using GPC) and from 500 to 900 ($M_w$ vs polystyrene using GPC). The dehydropolymerization of 1 and 2 seemed to initially produce a low-molecular-weight polymer, which then underwent an extensive cross-linking reaction of backbone Si-H bonds, leading to an insoluble network polymer.

해상운임에 영향을 미치는 주요 요인에 관한 연구

김명희,Kim, Myoung-Hee 한국항해항만학회 2022 한국항해항만학회지 Vol.46 No.4

In this study, a multivariate time series analysis was conducted to identify various variables that impact ocean freight rates in addition to supply and demand factors. First, we used the ClarkSea Index, Clarksons Average Bulker Earnings, and Clarksons Average Tanker Earnings provided by the Shipping Intelligence as substitute variables for the dependent variable, ocean freight. The following ndependent variables were selected: World Seaborne Trade, World Fleet, Brent Crude Oil Price, World GDP Growth Rate, Industrial Production (IP OECD) Growth Rate, Interest Rate (US$ LIBOR 6 Months), and Inflation (CP I OECD) through previous studies. The time series data comprise annual data (1992-2020), and a regression analysis was conducted. Results of the regression analysis show that the World Seaborne Trade and Brent Crude Oil P rice impacted the ClarkSea Index. Only the World Seaborne Dry Bulk Trade impacted the Clarksons Average Bulker Earnings, World Seaborne Oil Trade, Brent Crude Oil Price, IP, and CP I on the Clarksons Average Tanker Earnings.

비실험자료를 이용한 연구에서 인과적 추론의 강화: 성향점수와 도구변수 방법의 적용

김명희,도영경,Kim, Myoung-Hee,Do, Young-Kyung 대한예방의학회 2007 예방의학회지 Vol.40 No.6

Objectives : This study attempts to show how studies using non-experimental data can strengthen causal inferences by applying propensity score and instrumental variable methods based on the counterfactual framework. For illustrative purposes, we examine the effect of having private health insurance on the probability of experiencing at least one hospital admission in the previous year. Methods : Using data from the 4th wave of the Korea Labor and Income Panel Study, we compared the results obtained using propensity score and instrumental variable methods with those from conventional logistic and linear regression models, respectively. Results : While conventional multiple regression analyses fail to identify the effect, the results estimated using propensity score and instrumental variable methods suggest that having private health insurance has positive and statistically significant effects on hospital admission. Conclusions : This study demonstrates that propensity score and instrumental variable methods provide potentially useful alternatives to conventional regression approaches in making causal inferences using non-experimental data.

1998년 제주도에서 발생한 볼거리 유행조사

김명희,허영주,최보율,기모란,Kim, Myoung-Hee,Hu, Young-Joo,Choi, Bo-Youl,Ki, Mo-Ran 대한예방의학회 2001 Journal of Preventive Medicine and Public Health Vol.34 No.1

Objectives : To describe the characteristics of a mumps epidemic in Cheju-do, 1998 and to identify the risk factors associated with mumps infection. Methods : To estimate attack rate, previously collected data from the Nationally Notifiable Communicable Disease Reporting System and School Health Reporting System, temporarily administered by Division of Education. as well as additional surveillance data were used. In order to identify the clinical characteristics and risk factors associated with mumps, we conducted a questionnaire survey in 17 schools (9 elementary, 4 middle, and 4 high schools) among a population that included healthy students. Results : From March 3 to August 31, 2,195 cases of mumps were identified, and patients under 20 years of age accounted for 2,162 cases (attack rate 13.2, 95% CI 12.6-13.7/1,000). The attack rate for the population under 20 years of age was the highest in Nam county (44.7/1,000), nod in the 7-12 years old sub-group(>20.0/1,000). There was no sexual difference. 80.5% and 59.7% of patients presented periauricular and submandibular swelling respectively. Aseptic meningitis was a complication in 2.9% of cases, orchitis in 1.3%, epididymitis in 0.9% and oophoritis in 0.6% respectively. The overall MMR vaccination rate was 59.1% and it decreased in accordance with increasing age. In students aged 10 years old or below, household contact and MMR vaccination status was significantly associated with infection, and only among students with household contact, the risk of one dose MMR(OR=10.22, 95% CI 2.92-35.78) and non-vaccination (OR=11.62, 95% CI 1.96-68.96) was significantly greater when. compared with that of two dose vaccination. Among students aged 11 years old or above, household contact history was significantly associated and MMR vaccination status was not associated. Conclusions : Low vaccination rate and vaccine failure were thought to predispose the population for this large outbreak. To prevent sustained mumps outbreaks, a second MMR vaccination should be encouraged and catch up vaccinations should be given to elderly children who remain susceptible.

Capture-recapture 방법을 이용한 1998년 제주도 볼거리 유행시 보고 자료의 완전성 평가

김명희,박진경,기모란,허영주,김정순,최보율,Kim, Myoung-Hee,Park, Jin-Kyoung,Ki, Mo-Ran,Hur, Young-Joo,Kim, Joung-Soon,Choi, Bo-Youl 대한예방의학회 2000 Journal of Preventive Medicine and Public Health Vol.33 No.3

Objectives : To estimate mumps incidence during the study period and to evaluate the completeness of case reporting. Methods : Capture-recapture methods, originally developed for counting wildlife animals, were used. The data sources were 1) the National Notifiable Communicable Disease Reporting System (NNCDRS; 848 cases), 2) the School Health Reporting System, temporarily administered by the Division of Education (SHRS; 1,026 cases), and 3) a survey of students (785 cases). We estimated the number of unobserved mumps cases by matching the three data sources and fitting loglinear models to the data. We then determined the estimated total number of mumps cases by adding this to the number of observed cases. Completeness was defined as the proportion of observed cases from each source to the total of estimated cases. Results : The total number of observed cases was 1,844 and the total number of estimated cases was 1,935 (95%, CI: $1,878\sim2,070$). The overall completeness was 43.8% of the NNCDRS, 53.0% of the SHRS, and 40.6% of the survey. However, completeness varied by area and age. Conclusion : Although the completeness of NNCDRS data appeared higher than in the past, it is difficult to generalize this result In Korea, it is possible to estimate the size of health hazards relatively cheaply and quickly, by applying capture-recapture methods to various data using a multiple data collection system.

학교장의 감성리더십과 교사 직무만족의 관계에 미치는 LMX의 매개효과

김명희(Kim Myoung-Hee),양성관(Yang Sung-Kwan) 한국교육행정학회 2011 敎育行政學硏究 Vol.29 No.1

당(唐)의 이국적(異國的) 문화와 토공(土貢)에 관한 일고

김명희(Kim, Myoung-hee) 호남대학교 인문사회과학연구소 2004 人文社會科學硏究 Vol.11 No.-

토공(土貢)이란 당대(唐代) 주(州)나 부(府)의 특산물을 중앙 정부에 바친 공물(貢物)이었다. 이는 세금이 아닌 선물(膳物)의 성격을 지닌 것이었다. 토공의 품목들은 전국적으로 500여종이 넘고 있으며, 당(唐) 문화가 자랑했던 국제성(國際性)이나 당대인(唐代人)들의 이국적(異國的) 취향들이 잘 나타난다. 지금의 광동(廣東)·광서(廣西)·북부 베트남을 포함하는 남-비에트(Nam-Viet) 지역에서 주로 유입되었다. 예로서 사천(四川) 지방에서 보낸 토공이 가장 다양하였는데, 식물류로는 귤피(橘皮), 약실(藥實:약용 열매), 낙안목(落鴈木:밝혀지지 않은 식물), 홍람(紅藍:붉은 잇 꽃), 부이실(芣苢實:질경이 열매), 천문동(天門冬: 매끄러운 아스파라거스) 등이 있었고, 동물류로는 호미(狐尾:여우꼬리), 영양각(羚羊角), 우황(牛黃), 서각(犀角: 무소 뿔), 구어(鯄魚: 비늘 있는 숭어), 촉마(蜀馬)白蜜), 서우미(犀牛尾: 코뿔소 꼬리) 등이 포함되어 있었다. 또한 염사담(蚦蛇膽: 비단뱀 즙)이나 사향(麝香) 등도 남방 지방에서 나는 특산물로서 북방 중국인들이 선호하는 물품이었다. 토공은 궁극적으로 문화적 영역(領域)의 확대라는 효과를 가져왔으며, 나아가서 당대(唐代) 문화의 이국적 취향을 자극하는 매개체가 되었다. 문물을 통한 문화적 경험의 공유는 중국이 정치적으로나 지리적으로나 문화적으로 일체감을 가질 수 있는 계기가 되었다. “Treatise on the Configurations of the Land(Di-li Zhi:地理志)"", in the Xin Tang shu(新唐書), listed the commodities required annually by the central government as tribute from each and every region of the Tang empire. According to the records, in Tang China every major provincial subdivision, such as zhou(州) and fu(府), had to send various goods to the central government under the name of ""tribute-products of the earth(tu gong:土貢)"". It also shoud be the actual products of the named areas. In Tang times, tu-gong were a sort of levy tax but different kind from the produce-levies(fu:賦) which were allocated to the dao(道). It was meant to be a pure gift to the throne with voluntary gratitude from the people. Therefore, there were some restrictions on the value of the luxury items. If there were an extra amount, then it would be deducted from the produce-levies(fu:賦). There were more than 500 different articles were listed in Di-li Zhi(地理志) including all sorts of textiles, flora, fauna, minerals and manufactured goods; most of them can be easily identified. However, some Chinese-character can not be traced the exact meanings and in that case, they were usually presumed to be used as the medicine. In this study, some comparable goods from northern provinces are listed along with the products from southern part of Tang china, in particular, Jian-nan Dao(劒南道) and Ling-nan Dao(嶺南道). They include present provinces of An-nan(安南), Zhe-jiang(浙江), Fu-jian(福建), Gui-zhou(貴州), Guang-xi(廣西), Guang-dong(廣東), Si-chuan(四川) and Yun-nan(雲南). Among those, tributary articles, ascending hemp(升麻)·wiskered snake bile(蚦蛇膽)·drug-fruits(藥實)·sharks skins(鮫革)·sugar cane(蔗)·cinnabar sand(丹沙)·sharp iron(利鐵)·backgammon counters(雙陸子)·dried milk(乾酪)·musk aromatic(麝香) were included and these kinds were not difficult to identify. However, such as fallen wild-good(落鴈木) was difficult to identify. The tributary system, tu-gong is a core factor for the development of Tang dynasty not only in an expansion of territorial boundary, but in broadening cultural scope and exotic taste for the Tang people.

우리나라 해운기업의 부실예측에 관한 연구

김명희(Myoung Hee Kim),이기환(Ki Hwan Lee) 한국해양비즈니스학회 2016 해양비즈니스 Vol.- No.34

The purpose of this paper is to make the prediction models of business failure using multivariate discriminant analysis and logit analysis for Korean shipping compames. Many shipping compames have gone out of business and we find a list of companies closed a business between 2000 and 2014 in a report of cessation of business from the National Tax Service. Only 32 firms of all failure shipping companies were available to collect the financial statement in DART(Data Analysis, Retrieval and Transfer System) of the Financial Supervisory Service. Finally the 32 firms became a sample group for this study. And another normal 32 firms were chosen as a control group for comparison with failure firms. We considered 22 financial ratios of 5 categories for independent variables. And we selected independent variables by the result of t-test between two groups. Also the 32 paired firms were divided into two groups. One is to fit the prediction model and the other group is to test reliability of the fitting model. We assessed the accuracy in classification by hit ratio and reliability by predictive power. The results of this study are as follows. First, when using a year ago data from closing business, the hit ratio of two models is the same with 79.5%. However the predictive power of logit model with 75% is higher than discriminant model with 70%. Second, when using data of two-years ago, the hit ratio of discriminant model is 65 .0% and the predictive power is 66.7%. However the significance of discriminant model is not valid in the 95 % confidence level. In case of logit model, the hit ratio is 55.5% and the predictive power is 50%. The significance of logit model is valid in the 95 % confidence level however t-values of all independent variables are not significant.

우리나라 해운기업의 레버리지효과 분석

김명희 ( Kim Myoung-hee ) 한국해운물류학회(구 한국해운학회) 2020 해운물류연구 Vol.36 No.3

본 연구는 외항 해운기업의 영업레버리지효과와 재무레버리지효과를 통해 우리나라 해운기업의 총레버리지 효과를 살펴보기 위해 시도되었다. 금융감독원 전자공시시스템(DART)에서 재무 데이터 수집이 가능한 우리나라 해운기업을 대상으로 실증분석을 수행하였다. 호황기(2003-2007년)와 불황기(2013-2018년)를 구분하여 영업레버리지도 및 재무레버리지도가 어떻게 작동하는지 살펴보았다. 영업레버리지도의 경우 불황기(1.381)에 비해 호황기(6.434)에 5배 정도 더 크게 나타나는 것으로 분석되었다. 하지만 재무레버리지도의 경우 호황기(0.419)와 불황기(0.934) 모두에서 긍정적인 효과를 보이지는 못하는 것으로 해석할 수 있다. 이는 우리나라 해운기업이 불황기에 비해 호황기에 영업 위험이 크게 나타나 경영성과에 반영되지만 재무 위험은 그렇지 않은 것으로 분석되었다. 또한 영업위험과 재무위험에 영향을 줄 것으로 예상되었던 유형자산비중이나 부채비율이 기업의 총위험에 크게 관여되지 않는 것을 확인 할 수 있었다. This study was attempted to examine the operating and financial leverage effects of Korean shipping companies. An empirical analysis was conducted by the financial data from the Financial Supervisory Service Electronic Disclosure System (DART). The sample is divided into the period of the boom (2003-2007) and the recession (2013-2018). We analyzed how the degrees of operating and financial leverage work in Korean shipping companies. The degree of operating leverage was about 5 times larger during the boom (6.434) than during the recession (1.381). However, the degree of financial leverage did not show positive effects in both the boom (0.419) and the recession (0.934). It was analyzed that Korean shipping companies showed greater operating risk during boom than recession. However financial risk was not. In addition, the proportion of tangible assets and the debt ratio were expected to affect the operating and financial risks, but these were analyzed to be insignificant.