• The Korean Journal of Ceramics
• /
• 제1권1호
• /
• pp.7-12
• /
• 1995

When a $Ta_O_5$ dielectric film is deposited on a bare silicon, the growth of $SiO_2$ at the $Ta_O_5$/Si interface cannot be avoided. Even though the $SiO_2$ layer is ultrathin (a few nm), it has great effects on the electrical properties of the capacitor. The concentration depth profiles of the ultrathin interfacial $SiO_2$ and $SiO_2/Si_3N_4$ layers were obtained using an Auger electron spectroscopy (AES) equipped with a cylindrical mirror analyzer (CMA). These AES depth profiles were quantitatively analyzed by comparing with the theoretical depth profiles which were obtained by considering the inelastic mean free path of Auger electrons and the angular acceptance function of CMA. The direct measurement of the interfacial layer thicknesses by using a high resolution cross-sectional TEM confirmed the accuracy of the AES depth analysis. The $SiO_2/Si_3N_4$ double layers, which were not distinguishable from each other under the TEM observation, could be effectively analyzed by the AES depth profiling technique.

• 자원환경지질
• /
• 제28권1호
• /
• pp.33-41
• /
• 1995

Tin mineralizations in South Korea have been found only in the Ulchin and the Sangdong areas. The Wangpiri and the Yuchang Sn pegmatites appear to be in close spatial and genetical relation to the Wangpiri granitoid in the Ulchin area, and the Soonkyeong Sn pegmatite be in close association with the Nonggeori granites in the Sangdong area from geochemical viewpoint. The electron-microprobe analysis of muscovite, biotite, tourmaline and cassiterite from the granitoids and pegmatites in the Ulchin and the Sangdong areas has revealed a distinct differences of geochemical compositions. The Wangpiri and the Yuchang Sn pegmatites show an enrichment of MnO and a depletion of $TiO_2$, FeO and MgO in comparison with the Soonkyeong Sn pegmatite. This result coincides with the geochemical compositions of granitoid rocks in these areas. Enrichment of MnO and depletion of $TiO_2$ FeO and MgO are characteristic in muscovite, biotite and tourmaline of pegmatites compared with those of granitoids. These geochemical differences of muscovite, biotite and tourmaline between granitoids and pegmatites in these areas implies that pegmatites are more fractionated than granitoids.

• 한국진공학회지
• /
• 제16권3호
• /
• pp.205-209
• /
• 2007

Atomic layer deposition(ALD)를 이용하여 Si와 soda lime glass 기판 위에 ZnO 박막을 증착하였다. 기판의 온도는 비교적 저온인 $130^{\circ}C{\sim}150^{\circ}C$를 채택하였다. 증착결과 단위 cycle 당 $2.72{\AA}$이 증착되어 균일한 박막이 증착되었음이 확인되었다. 증착된 박막의 결정성을 X-ray diffraction(XRD)으로 조사해본 결과 비교적 저온에서도 (100)과 (101)방향의 성장이 우세하였다. 또 Auger electron spectroscopy(AES)로 분석해본 결과 불순물이 없는 순도 높은 박막이 성장되었음을 알 수 있었다.

• Transactions on Electrical and Electronic Materials
• /
• 제8권6호
• /
• pp.274-277
• /
• 2007

In this study, liquid crystal(LC) aligning capabilities for homeotropic alignment on the $SiO_x$ thin film by electron beam evaporation method were investigated. Also, the control of pretilt angles and thermal stabilities of the nematic liquid crystal(NLC) treated on $SiO_x$ thin film were investigated. A high pretilt angle of about $86.5^{\circ}$ was obtained, and also the suitable pretilt angle of the NLC on the $SiO_x$ thin film at $10{\sim}50nm$ thickness with e-beam evaporation can be achieved. The uniform LC alignment and good thermal stabilities on the $SiO_x$ thin film surfaces with electron beam evaporation can be achieved. It is considered that the LC alignment on the $SiO_x$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_x$ thin film surface created by evaporation.

• 한국진공학회지
• /
• 제7권3호
• /
• pp.208-213
• /
• 1998

최근 셀리사이드(salicide) 제조시 $COSiO_2$의 에피텍셜 성장을 돕기 위하여 Ti층을 삽 입한 Co/Ti/Si 이중층 구조의 실리사이드화가 관심을 끌고 있다. Co/Ti 이중층을 이용한 salicide 트랜지스터가 성공적으로 만들어지기 위해서는 gate 주위의 spacer oxide위에 증착 된 Co/Ti 이중층을 급속열처리할 때 Co/Ti와 $SiO_2$간의 계면에서의 상호반응에 대하여 조사 하였다. Co/Ti 이중층은 $600^{\circ}C$에서 열처리한 후 면저항이 급격하게 증가하기 시작하였는데, 이것은 Co층이 $SiO_2$와의 계면에너지를 줄이기 위하여 응집되기 때문이다. 이때 Co/Ti의 열 처리후 Ti에 의하여 $SiO_2$기판의 일부가 분해됨으로써 절연체의 Ti산화물이 형성되었으나, 이외의 도전성 반응부산물은 발견되지 않았다.

• 한국세라믹학회지
• /
• 제43권1호
• /
• pp.33-37
• /
• 2006

For producing the fine ribs structure of plasma display panel, the metal ions of barrier materials during the etching process should be understood on the etching mechanism with etching conditions. Etching was done on bulk glasses of the $BaO_B_2O_3-ZnO$ system with $HNO_3$ solution at $40^{\circ}C$. The surface structure of glasses and ion dissolution were analyzed by ICP (Inductive Coupled Plasma measurement). The structure and surface of the etched bulk glass were investigated by using scanning electron microscopy and nanoindenter. As a result, Ba (3-35 ppm/min) and Zn (2-27 ppm/min) ions as major components were leached in the solution and the leached layers were found to be phosphor-rich surface layers. A decrease of the bridge oxygen and relative increase of non bridge oxygen in the etched glass were found by X-ray photoelectron spectroscopy.

• 한국세라믹학회지
• /
• 제31권12호
• /
• pp.1561-1569
• /
• 1994

Effect of calcining temperature on the sintering behaviors and microwave dielectric properties of BMT[Ba(Mg1/3Ta2/3)O3] ceramics was studied. The calcining temperatures were varied from 80$0^{\circ}C$ to 130$0^{\circ}C$, respectively. It was found that, as calcining temperature lowered below 125$0^{\circ}C$, second phase such as Ba5Ta4O15 phases started to appear in calcined powder with unreacted powders. After sintering, exaggerately grown Ba5TaO3 phase could be found amang the uniform BMT grains in sintered body. Basis on the infiltration experiment, Ba0.05TaO3 phase should be formed by reaction of BMT grain and BaO-MgO eutectic liquid. But increase of calcining temperature above 125$0^{\circ}C$, there was not any second phase or unreated component in calcined powder and sintered body. As result, low calcining temperature led to precipitation of second phase in specimen and resulted decrease of Q value of BMT ceramics.

• BMB Reports
• /
• 제35권4호
• /
• pp.403-408
• /
• 2002

A hypothetical 21.0 kDa protein (ORF O197) from Escherichia coli K-12 was cloned, purified, and characterized. The protein sequence of ORF O197(termed EcO197) shares a 33.5% identity with that of a novel NTPase from Methanococcus jannaschii. The EcO197 protein was purified using Ni-NTA affinity chromatography, protease digestion, and gel filtration column. It hydrolyzed nucleoside triphosphates with an O6 atom-containing purine base to nucleoside monophosphate and pyrophosphate. The EcO197 protein had a strong preference for deoxyinosine triphosphate (dITP) and xanthosine triphosphate (XTP), while it had little activity in the standard nucleoside triphosphates (dATP, dCTP, dGTP, and dTTP). These aberrant nucleotides can be produced by oxidative deamination from purine nucleotides in cells; they are potentially mutagenic. The mutation protection mechanisms are caused by the incorporation into DNA of unwelcome nucleotides that are formed spontaneously. The EcO197 protein may function to eliminate specifically damaged purine nucleotide that contains the 6-keto group. This protein appears to be the first eubacterial dITP-and XTP-hydrolyzing enzyme that has been identified.

• 공업화학
• /
• 제26권6호
• /
• pp.692-697
• /
• 2015

본 연구에서는 바닥재에 CaO와 $Al_2O_3$를 중량비로 각각 10~40% (W/W)로 첨가 후 7일 및 28일을 양생시킨 다음 중금속 용출 저감 효율에 대한 영향 등을 연구하였다. 실험결과, 7일 양생 기간에서는 구리 69.3%, 납 52.1%의 중금속 저감 효율을 보였다. 28일 양생 시에는 구리 85.2%, 납 100% 제거 효율을 보였다. 위 실험결과 양생 시간이 길어질수록 높은 중금속 저감 효율을 보이는 것을 확인할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 추계학술대회 논문집
• /
• pp.125-128
• /
• 2007

In these recent years, low cost and stable battery electrode materials have been studied for HV/HEV application. Spinel cathode material $LiMn_2O_4$ is widely studied as a promising cathode material of lithium ion secondary batteries because of it is low cost, easily to be prepared and capable to be operated in high voltage range. In this study, $LiMn_2O_4$ was undergoing surface modification with spinel lithium titanium oxide by sol-gel method in order to enhance its capacity retention. Properties of both unmodified and surface-modified $LiMn_2O_4$ were characterized by XRD, SEM, particle size analyzer while their cycling performance was tested with charge and discharge tester.