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 : Mahtab Ullah (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Influence of boron carbide on properties of CVD-diamond thin films at various deposition pressures
Mahtab Ullah,E. Ahmed 한국물리학회 2012 Current Applied Physics Vol.12 No.3
Microcrystalline boron-doped diamond (BDD) films are synthesized on the silicon substrate by the hotfilament chemical vapor deposition method under the gas mixture of hydrogen and methane in the presence of boron carbide (B4C) placed in front of filaments. The observed results of scanning electron microscopy, Raman spectroscopy and X-ray diffraction show the morphologies. Microstructures for various deposition pressures of as-grown diamond films are found to be dependent on the change of deposition pressure. These results reveal that with the increase of deposition pressure, resistivity decreases and increase in the grain size is noted in the presence of B4C. Resistivity shows a sudden fall of about three orders of magnitude by the addition of boron in the diamond films. This is due to the crystal integrity induced by B-atoms in the structure of diamond in the presence of B4C. These results are also significant for the conventional applications of BDD materials. The effects of deposition pressure on the overall films morphology and the doping level dependence of the diamond films have also been discussed.
-
Idrees, Muhammad,Batool, Saima,Ullah, Hidayat,Hussain, Qaiser,Al-Wabel, Mohammad I.,Ahmad, Mahtab,Hussain, Amjad,Riaz, Muhammad,Ok, Yong Sik,Kong, Jie Elsevier 2018 Journal of molecular liquids Vol.266 No.-
<P><B>Abstract</B></P> <P>In the present investigation, poultry manure and farmyard manure-derived biochars were applied as cost-effective adsorbents for manganese (Mn) removal from aqueous media. Effects of functional parameters such as solution pH, contact time, temperature and concentration on the Mn removal efficiency of biochars were evaluated. Poultry manure-derived biochar exhibited greater adsorption efficiency than farmyard manure-derived biochar due to its porosity and surface functionality. The maximum adsorption was achieved at pH 6, temperature 298 K and contact time of 3 h. The adsorption isotherm data was well fitted to the Freundlich model indicating multilayer adsorption onto heterogeneous surfaces of the biochars. Thermodynamics calculations affirmed that Mn adsorption onto biochars was spontaneous and exothermic process governed by hydrogen bonding type of electrostatic interaction. Post-adsorption spectroscopic analysis of Mn-loaded biochars evidenced the binding of Mn with active surface functionalities of biochars.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biochar, a by-product of pyrolysis, was prepared as a low cost adsorbent precursor. </LI> <LI> Effect of derived biochars on Manganese removal efficiency was investigated. </LI> <LI> FBC and PBC characteristics were analyzed. </LI> <LI> Langmuir and Freundlich models were used for equilibrium modeling. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
