논단 1-전도성 SiC 복합체의 개발과 방전가공

신용덕,Sin, Yong-Deok 한국전기산업진흥회 1997 電氣産業 Vol.8 No.3

YAG와 기공에 의한 $SiC-TiB_2$ 전도성세라믹 복합체의 특성 평가

신용덕,이동윤,Sin, Yong-Deok,Lee, Dong-Yun 대한전기학회 2001 전기학회논문지C Vol.50 No.11

The mechanical and electrical properties of the hot-pressed and pressureless annealed SiC-39vo1.%TiB$_2$electroconductive ceramic composites were investigated as functions of the liquid additives of $Al_2O_3+Y_2O_3$ and the sintering temperature. The result of phase analysis for the SiC-39vo1.%TiB$_2$ composites by XRD revealed $\alpha -SiC(6H),\; TiB_2,\; and YAG(Al_5Y_3O_{12})$ crystal phase. The relative density of SiC-39vo1.% $TiB_2$ composites was increased with increased $Al_2O_3+Y_2O_3$ contents. The fracture toughness showed the highest value of $7.8 MPa.m_{1/2}$ for composites added with 12 wt% $Al_2O_3+Y_2O_3$additives at $1750^{\circk}C$. The electrical resistivity of the SiC-39vo1.%$TiB_2$composites was all positive temperature coefficient resistance(PTCR) in the temperature range of $25S^{\circ}C \;to\; 700^{\circ}C$.

無加壓 열처리에 의한 ${\beta}$-SIC-TiB$_2$ 複合體의 製造와 特性

신용덕,주진영,박미림,Shin, Yong-Deok,Ju, Jin-Young,Park, Mi-Lim 대한전기학회 2001 전기학회논문지C Vol.49 No.5

The effect of $Al_2O_3+Y_2O_3$ additives on fracture toughness of ${\beta}-SiC-TiB_2$ composites by hot-pressed sintering was investigated. The ${\beta}-SiC-TiB_2$ ceramic composites were hot-press sintered and pressureless-annealed by adding 16, 20, 24 wt% ${\beta}-SiC-TiB_2$(6:4 wt%) powder as a liquid forming additives at low temperature(1800 $^{\circ}C$) for 4 h. Phase analysis of composites by XRD revealed mostly of ${\alpha}$-SiC(6H), $TiB_2$, and YAG($Al_5Y_3O_{12}$). The relative density was over 95-88 % of the theoretical density, and the porosity increased with increasing $Al_2O_3+Y_2O_3$ contents because of the increasing tendency of pore formation. The fracture toughness showed the highest value of 5.88 MPa${\cdot}m^{1/2}$ for composites added with 20 wt% $Al_2O_3+Y_2O_3$ additives at room temperature. The electrical resistivity showed the lowest value of $5.22{\times}10^{-4}\;{\Omega}\;{\cdot}\;cm$ for composite added with 20 wt% $Al_2O_3+Y_2O_3$ additives at room temperature, and was all positive temperature coefficeint resistance(PTCR) against temperature up to 900 $^{\circ}C$.

Phase Degree of Response Voltage and Current Versus Excitation Voltage of the Accelerated Thermally Aged CSPE

신용덕 한국전기전자재료학회 2018 Transactions on Electrical and Electronic Material Vol.19 No.2

As the accelerated thermally aged years of CSPE samples increase, their resistivity and percent elongation decrease. On theother hand, their dissipation factors, glass transition temperatures, and apparent densities increase with increasing ageingtimes. The phase degree of response current versus excitation voltage of a CSPE sample decreased in agreement with thetendency of resistivity, while the phase degree of response voltage versus excitation voltage increased in agreement with thetendency of conductivity. The variations in temperature for an applied AC voltage are higher than those for a DC voltage.

인간난자 체외수정의 반복주기에서 과배란유도반응에 관한 연구

신용덕,김정구,문신용,이진용,장윤석 대한산부인과학회 1987 대한산부인과학회 학술대회 Vol.60 No.-

경자성 재료의 개발현황과 연구동향

신용덕,송준태 한국전기전자재료학회 1996 電氣電子材料學會誌 Vol.9 No.1

연질자성재료는 대부분 직류 및 고주파용 변압기, inductor, 대형 motor, 자기헤드의 자심재료 및 센서등으로 사용되고, 경질자성재료는 주로 motor 및 speaker용으로 사용되며, 자기기록매체재료는 화상, 음성 및 컴퓨터 정보의 기록용으로 사용된다. 특수자성재료로는 microwave용, 전자파 흡수, 열팽창 제어, 기체밀봉등 많은 용도에 이용되고 있다. 최근 국내외에서 수요가 급증하는 첨단 전자기기용 자성재료 시장등이 내구, 내열성 뿐만 아니라 소형화, 경량화 됨에 따라 자성재료의 고성능화를 요구하고 있다. 따라서 본 고에서는 경질자성재료의 개발현황을 살펴보고 자성재료의 고성능화를 위한 연구동향을 생각해 보고자 한다.

상압소결(常壓燒結)한 $SiC-ZrB_2$ 전도성(電導性) 복합체(複合體)의 미세구조(微細構造)와 특성(特性)에 미치는 Annealing 온도(溫度)의 영향(影響)

신용덕,주진영,Shin, Yong-Deok,Ju, Jin-Young 대한전기학회 2006 전기학회논문지C Vol.55 No.9

The effect of pressureless-sintered temperature on the densification behavior, mechanical and electrical properties of the $SiC-ZrB_2$ electroconductive ceramic composites was investigated. The $SiC-ZrB_2$ electroconductive ceramic composites were pressureless-sintered for 2 hours at temperatures in the range of $1,750{\sim}1,900[^{\circ}C]$, with an addition of 12[wt%] of $Al_2O_3+Y_2O_3$(6:4 mixture of $Al_2O_3\;and\;Y_2O_3$) as a sintering aid. The relative density and mechanical properties are increased markedly at temperatures in the range of $1,850{\sim}1,900[{^\circ}C]$. The relative density, flexural strength, vicker's hardness and fracture toughness showed the highest value of 81.1[%], 230[MPa], 9.88[GPa] and $6.05[MPa\;m^{1/2}]$ for $SiC-ZrB_2$ composites of $1,900[{^\circ}C]$ sintering temperature at room temperature respectively. The electrical resistivity was measured by the Pauw method in the temperature ranges from $25[{^\circ}C]\;to\;700[{^\circ}C]$, The electrical resistivity showed the value of $1.36{\times}10^{-4},\;3.83{\times}10^{-4},\;3.51{\times}10^{-4}\;and\; 3.2{\times}10^{-4}[{\Omega}{\cdot}cm]$ for SZ1750, SZ1800, SZ1850 and SZ1900 respectively at room temperature. The electrical resistivity of the composites was all PTCR(Positive Temperature Coefficient Resistivity). The resistance temperature coefficient showed the value of $4.194{\times}10^{-3},\;3,740{\times}10^{-3},\;2,993{\times}10^{-3},\;3,472{\times}10^{-3}/[^{\circ}C}$ for SZ1750, SZ1800, SZ1850 and SZ1900 respectively in the temperature ranges from $25[{\circ}C]\;to\;700[{\circ}C]$, It is assumed that because polycrystallines such as recrystallized $SiC-ZrB_2$ electroconductive ceramic composites, contain of porosity and In Situ $YAG(Al_5Y_3O_{12})$ crystal grain boundaries, their electrical conduction mechanism are complicated. In addition, because the condition of such grain boundaries due to $Al_2O_3+Y_2O_3$ additives widely varies with sintering temperature, electrical resistivity of the $SiC-ZrB_2$ electroconductive ceramic composites with sintering temperature also varies with sintering condition. It is convinced that ${\beta}-SiC$ based electroconductive ceramic composites for heaters or ignitors can be manufactured by pressureless sintering.

무가압소결한 $\beta$-SiC-$ZrB_2$계 도전성 복합체의 제조 및 기계적, 전기적 특성

신용덕,권주성,Shin, Yong-Deok,Kwon, Ju-Sung 대한전기학회 1999 전기학회논문지C Vol.48 No.2

The effect of $Al_2O_3$ additives to $\beta-SiC+39vol.%ZrB_2$ electroconductive ceramic composites by pressureless sintering on microstructural, mechanical and electrical properties were investigated. The $\beta-SiC+39vol.%ZrB_2$ ceramic composites were pressureless sintered by adding 4, 8, 12wt.% $Al_2O_3$ powder as a liquid forming additives at $1950^{\cire}C$ for 1h. Phase analysis of composites by XRD revealed mostly of $\alpha-SiC(6H), ZrB_2$ and weakly $\alpha-SiC(4H), \beta-SiC (15R)$ phase. The relative density of composites was lowered by gaseous products of the result of reaction between \beta-SiC and Al_2O_3$, therefore, porosity was increased with increasing $Al_2O_3$ contents, and showed the maximum value of 1.4197MPa.$m^{1/2}$ for composite with 4wt.% $Al_2O_3$ additives. The electrical resistivity of $\beta-SiC+39vol.%ZrB_2$ electroconductive ceramic composite was increased with increasing $Al_2O_3$ contents, and showed positive temperature coefficient resistance (PTCR) in the temperature range of $25^{\cire}C$ to $700^{\cire}C$.

인간난자 체외수정 및 생식자 난관내이식술의 반복주기에서 과배란유도반응에 관한 연구

신용덕,김정구,문신용,이진용,장윤석,Shin, Yong-Duk,Kim, Jung-Gu,Moon, Shin-Yong,Lee, Jin-Yong,Chang, Yoon-Seok 대한생식의학회 1987 Clinical and Experimental Reproductive Medicine Vol.14 No.2

In order to evaluate the consistency of the serum estradiol pattern and response and to determine the influence of number of ovary on them in repeat cycles in the same patient, 57 cycles in 24 patients who underwent in Vitro Fertilization-Embryo Transfer or Gamete Intrafallopian Transfer in Seoul National University Hospital. The patients were stimulated by follicular stimulating hormone and human menopausal gonadotropin and classified as high(${\geqq}$400 pg/ml) and low(<400 pg/ml) response group according to preovulatory estradiol concentration and classified as three estradiol patterns (A,G.B) according to Jones criteria. Seventeen(89.5%) of 19 patients in when a high response to ovulation induction in their first cycle showed a high response. 40%(2/5) of the second ovulation induction cycle were low response in the patient whose first cycle resulted resulted in a low response. Serum estradiol pattern in the first ovulation induction cycle tended to be repeated in the second cycle. Women with high response tended to be more likely to have A and G patterns and less likely to have a cancellation than those with low response. One-ovary patients were at higher risk for inadequate ovulation induction response.

지방공기업 전출금 지원 실태와 관리체계 개선과제

신용덕 한국지방공기업학회 2015 한국지방공기업학회보 Vol.11 No.2

지방재정의 구조적 불균형은 세입 확충과 통합부채 감축 외에도 효과적인 재정지출을 위한 제도적 노력이 수반되어야 한다. 예산외기관(off-budget entity)인 지방공기업의 재정손실이 확대되는 상황에서 이들 기관에 대한 지방정부의 재정지출을 효율적으로 관리할 필요가 있다. 이러한 배경 하에 지방재정연감을 중심으로 지방공기업 전출금 지원규모를 분석하고, 지방정부와의 재정관계를 고려하여 관리체계 개선방안을 모색하였다. 분석결과, 2002년부터 2013년까지 12년간 지방공기업 경상전출금과 자본전출금은 총 27조원으로 연평균 2조원에 이르며, 회계유형별로는 기타특별회계를 통한 지원이 14조원으로 가장 많으며, 지방공기업 경영형태별로는 공사공단에 17조원, 전출금 성질별로는 경상전출금으로 16조원을 지출하였다. 지역별로는 서울(7조원)･부산(6조원)･경기(4조원) 순으로 특･광역시에 편중된 것으로 나타났다. 이러한 결과를 토대로 지방공기업의 부채 증감율과 지방정부의 전출금 증감률 간에 정(+)의 상관관계를 추정하였다. 향후 지방공기업 유형과 지역별 전출금 규모에 대한 면밀한 조사연구가 필요하며, 제도적 차원에서 지방공기업 전출금 지원의 배분원칙과 관리체계가 마련될 필요가 있다.