http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 주기태 (검색결과 29 건)
- 무료
- 기관 내 무료
- 유료
-
텅스텐 브론즈 Sr<sub>1-x</sub>Ba<sub>x</sub>Nb<sub>2</sub>O<sub>6</sub> 단결정의 성장 특성
주기태,강봉훈,Joo, Gi-Tae,Kang, Bonghoon 한국재료학회 2012 한국재료학회지 Vol.22 No.12
Tungsten bronze structure $Sr_{1-x}Ba_xNb_2O_6$ (SBN) single crystals were grown primarily using the Czochralski method, in which several difficulties were encountered: striation formation and diameter control. Striation formation occurred mainly because of crystal rotation in an asymmetric thermal field and unsteady melt convection driven by thermal buoyancy forces. To optimize the growth conditions, bulk SBN crystals were grown in a furnace with resistance heating elements. The zone of $O_2$ atmosphere for crystal growth is 9.0 cm and the difference of temperature between the melt and the top is $70^{\circ}C$. According to the growth conditions of the rotation rate, grown SBN became either polycrystalline or composed of single crystals. In the case of as-grown $Sr_{1-x}Ba_xNb_2O_6$ (x = 0.4; 60SBN) single crystals, the color of the crystals was transparent yellowish and the growth axis was the c-axis. The facets of the crystals were of various shapes. The length and diameter of the single crystals was 50~70 mm and 5~10 mm, respectively. Tungsten bronze SBN growth is affected by the temperature profile and the atmosphere of the growing zone. The thermal expansion coefficients on heating and on cooling of the grown SBN single crystals were not matched. These coefficients were thought to influence the phase transition phenomena of SBN.
-
-
주기태,이태근,박미혜,황연 한국세라믹학회 2012 한국세라믹학회지 Vol.49 No.6
Geopolymers were synthesized using raw materials produced from two different areas: one was from Indonesia and the other was from Habcheon, Korea. The constituting phases of the Indonesian raw material were quartz and kaolinite, while those of the Habcheon sample were quartz, halloysite and albite. They were both calcined at 750oC for 6 hours, and solution of NaOH and water glass was added to activate the geopolymeric reaction. The compressive strength of geopolymer synthesized from the Indonesian raw material showed a low value of 151 kgf/cm2 after curing for 28 days. However, it could be greatly increased by adding blast furnace slag powders of 1188 kgf/cm 2 and 1969 kgf/cm2 at 20 wt% and 40 wt% additions, respectively. The compressive strength of the geopolymer synthesized from the Habcheon raw material was high, at 557 kgf/cm2, after 28 days, and the very high early-stage (3 days) strength of 556 kgf/cm2 for this sample was remarkable. Commercially available Habcheon metastate raw material, of which composition showed low CaO and Na2O contents compared to the calcined Habcheon raw material, was also examined. It was found that the compressive strength of the commercial metastate type was nearly identical to that of the calcined Habcheon raw material except for the relatively low value at an early curing stage and at a high curing temperature of 60oC.
-
-
알칼리 토속 산화물이 물라이트 자기의 전기적 특성에 미치는 영향
주기태,장성도 한국세라믹학회 1981 한국세라믹학회지 Vol.18 No.3
Alkaline-earth porcelains have been prepared from mixture of kaolin, quartz, and synthetic calcines obtained by calcining a mixture of kaolin and more than two different kinds of alkaline-earth carbonates. They were magnesium, calcium and barium carbonates which are inexpensive and readily available. The vitrification behavior of the batch mixes was investigated in the firing range of 1240$^{\circ}$to 1380$^{\circ}$, in relation to the body compositions. It appeared that the density and the firing temperature depended largely on the content of alkaline-earth oxides in the body. These porcelains posses excellant dielectric properties, and are especially valuable as bases for deposited carbon resistors for which they were developed. An illustrative composition is 50% Dong Hwa kaolin, 22.4% Chang Shin quartz, 27.6% calcine. The composition of the calcine is 70% Dong Hwa kaolin, 10.7% BaCO3, 13.5% CaCO3, 5.8% MgCO3. The specific resistance of this body is $1.2{\times}10^{15}$ ohm-cm at 5$0^{\circ}C$, $2.5{\times}10^{14}$ ohm-cm 10$0^{\circ}C$, $2.5{\times}10^{13}$ ohm-cm at 15$0^{\circ}C$, $1.8{\times}10^{12}$ohm-cm at 20$0^{\circ}C$.
-
Optimization of the Input Fundamental Beam by Using a Spatial Filter Consisting of Two Apertures
강봉훈,주기태,Bum Ku Rhee 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.1
The primary importance of the power efficiency of second-harmonic generation (SHG) is determined by using the spatial shape of the fundamental input beam, its confocal parameter. The improvement of the fundamental input beam by using a spatial filter consisting of two apertures. The beam quality factor M2 of the improved fundamental beam was about 2.3.
-
Power Characteristics of cw Second-harmonic Generation in Periodically Poled LiNbO3
강봉훈,주기태,이범구 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.5
We verified through a noncritical phase-matched second-harmonic generation experiment that the periodically-poled LiNbO3 (PPLN) had a large effective nonlinear optical coefficient, demonstrating that the QPM grating was uniform throughout the entire length of PPLN. The quasi-phase matching temperature was 193.4oC. The maximum SHG output power at the fundamental power of 2.0 W was found to be 18.0 mW; generated second-harmonic beam was found to have no photorefractive effect.
-
-
Sr1-xBaxNb2O6의 유전 특성에 대한 산화/환원 열처리의 영향
강봉훈,주기태,백영섭 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.3
Sr1-xBaxNb2O6(SBN) have been obtained in Pt crucible by melting and cooling in air atmosphere. Some SBNs being at the bottom of the crucible are black and transparent, and the other SBNs colorless. The black SBN became to be colorless by oxidation heat treatment 1,300℃ for 4hr, Curie temperature is changed by colorless change of black SBN. The reason seems to be Nb5+ oxidation of some Nb4+ ions in SBN or effect of unknown impurities. Diffused phase transition(DPT) was appeared during heating and cooling process. Various sintered SBN ceramics specimen showed relaxor characteristics.
-
수열합성법에 의한 미립의 $BaTiO_3$ 분말합성 및 특성
배동식,주기태,한경섭,최상흘 한국결정성장학회 1998 韓國結晶成長學會誌 Vol.8 No.4
$BaTiO_3$ fine particles were prepared by hydrothermal process from titanium tetra-isoproproxide ($Ti(OiPr)_4$) and barium hexa-hydroxide ($Ba(OH)_2{cdot}8H_2O$) as raw materials. The fine particles were obtained at the temperature range of 160 to $185^{\circ}C$. The properties of $BaTiO_3$ particles were studied as a function of various parameters such as reaction temperature, reaction time and Ba/Ti ratio, etc. The average particle size of $BaTiO_3$ increased with increasing reaction temperature and time. After hydrothermal treatment at $170^{\circ}C$ for 8 h, the average particle size of $BaTiO_3$ was about 30 nm and the particle size distribution was narrow. BaTiO3 분말은 티타늄 수산화물 용액과 비륨수산화물 용액을 혼합하여 적당한 온도와 압력하에서 합성되었다. 미분말이 얻어진 온도는 160~$185^{\circ}C$, 압력은 5~10kg/$\textrm{cm}^2$이였다. 분말의 모양과 크기는 주사전자현미경, 결정 상은 X-선 회절로 분석하였다. 분말합성온도, 반응시간 및 농도변화에 따르는 분말의 물성을 조사하였다. $BaTiO_3$ 분말의 평균입자크기는 반응온도 및 시간이 증가함에 따라 증가하였다. $170^{\circ}C$에서 8시간 반응시킨 경우의 평균입자크기는 약 30nm이고, 입도 분포는 균일하였다.
ScienceON
코리아스칼라연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
