• Korean Chemical Engineering Research
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• 제45권3호
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• pp.269-276
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• 2007

$TiO_2$ 함유 피치섬유의 최적 안정화 조건을 도출하기 위하여 $TiO_2$의 함유량을 달리하여 피치섬유를 제조한 후, 여러가지 안정화 조건에 대한 섬유의 특성 변화와 금속입자의 거동을 관찰하였다. 공기에 의한 피치섬유의 안정화시 안정화온도가 높고, $TiO_2$ 함유량이 적을수록 산화에 의한 무게증가가 컸다. 안정화된 섬유를 탄화하면 수율은 71~82 wt.% 수준인데, $TiO_2$가 활성촉매 역할을 하여 $TiO_2$의 함유량이 많을수록 탄화수율은 낮았다. 안정화 과정에서 열가소성의 피치섬유는 산소의 도입으로 카르보닐기(C=O)와 카르복실기(-COOH) 등이 형성되며 동시에 이들이 가교결합을 이루고 수소를 탈리시켜 열경화성 섬유로 전환되었다. 활성탄소섬유의 기공크기는 $TiO_2$ 함유량이 증가함에 따라 점점 커졌으며, 주사전자현미경과 투과전자현미경을 통하여 섬유의 표면과 내부에 분포된 $TiO_2$ 입자와 분포를 관찰한 결과 안정화, 탄화 및 활성화공정 중 일부 $TiO_2$가 서로 뭉침을 알 수 있었다. 최종적으로 0.5 wt.% $TiO_2$ 함유 석유계 피치섬유는 $280^{\circ}C$에서 3 hr를 최적 안정화 조건으로 제시할 수 있었다.

• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.57-62
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• 2022

The plasma resistance of multi-component glasses containing La, Gd, Ti, Zn, Y, Zr, Nb, and Ta was analyzed in this study. The plasma etching was performed via inductively coupled plasma-reactive ion etching (ICP-RIE) using CF₄/O₂/Ar mixed gas. After the reaction, the glass with a low fluoride sublimation temperature and high content of P, Si, and Ti elements showed a high etching rate. On the other hand, the glass containing a high fluoride sublimation temperature component such as Ca, La, Gd, Y, and Zr exhibited high plasma resistance because the etch rate was lower than that of sapphire. Glass with low plasma resistance increased surface roughness after etching or nanoholes were formed on the surface, but glass with high plasma resistance showed little change in surface microstructure. Thus, the results of this study demonstrate the potential for the development of plasma-resistant glasses (PRGs) with other compositions besides alumino-silicate glasses, which are conventionally referred to as plasma-resistant glasses.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1155-1162
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• 2015

This study aimed to evaluate the nutrient digestibility of growing rabbits fed diets with different levels of either Leucaena leucocephala (LLM) or Moringa oleifera (MOLM) leaf meals and also to compare total collection and $TiO_2$ marker methods for estimating digestibility. A total of 30 California growing rabbits ($1.81{\pm}0.19kg$ live weight on average) were randomly distributed into five experimental groups of six rabbits each and were housed in individual cages. The groups were control, 30% LLM, 40% LLM, 30% MOLM, and 40% MOLM. All groups received pelleted diets for two weeks; diets also contained 4 g/kg titanium dioxide as dietary marker. Daily feed intake was recorded during the whole experimental period and total feces were collected daily and weighed individually during four days. The results showed that there were no difference (p>0.05) in feed, dry matter (DM), organic matter (OM), crude protein (CP), digestible energy, and crude fiber (CF) intake between the control group and the other experimental groups. The apparent digestibility values of DM, OM, CP, CF, acid detergent fiber, and gross energy were the highest for control group (p = 0.001), meanwhile MOLM diets had generally higher nutrient digestibility coefficients than LLM diets. Increasing the inclusion level of leaf meal in the diet from 30% to 40% improved the digestibility of CF from 45.02% to 51.69% for LLM and from 48.11% to 55.89% for MOLM. Similar results for apparent nutrient digestibility coefficients were obtained when either total collection or indigestible marker method was used. In conclusion, the digestibility of MOLM containing diets were better than LLM diets, furthermore $TiO_2$ as an external marker could be used as a simple, practical and reliable method to estimate nutrients digestibility in rabbit diets.