排序方式: 共有57条查询结果,搜索用时 46 毫秒
1.
Aloysius Soon Joel Wallman Bernard Delley Catherine Stampfl 《Current Applied Physics》2013,13(8):1707-1712
We present a trend study of a large variety of dopants at the cation site in Cu2O (i.e. substituting Cu), focussing largely on the early 3d-, 4d-, and 5d-transition metals (TMs) in which many of them are known to be non-magnetic. We also include s-, sp- and d10-metals for comparison. We find that doping with sp-elements results in zero spin moment while dopants with a partially filled d-band show a stronger tendency to magnetize and 3d-TM dopants exhibit a larger magnetic moment than most of the 4d- and 5d-TM dopants. From this trend study, we also find a correlation between their substitution enthalpy and associated interatomic relaxations. In particular, Ti-doped Cu2O appears to be an interesting system, given its “peculiar” ability to exhibit a spin moment when doped with a non-magnetic substituent like Ti. We also find that the interaction between two doped Ti atoms in Ti2:Cu2O is predominantly antiferromagnetic, and interestingly (and unexpectedly), this interaction rapidly declines as a function of inter-dopant distance, as in the case for the magnetic late-TM dopants like Co2:Cu2O. 相似文献
2.
Andrew J. Thompson Dr. Jerome Dabin Javier Iglesias‐Fernández Dr. Albert Ardèvol Dr. Zoran Dinev Assoc. Prof. Spencer J. Williams Dr. Omprakash Bande Dr. Aloysius Siriwardena Carl Moreland Dr. Ting‐Chou Hu David K. Smith Prof. Harry J. Gilbert Prof. Carme Rovira Prof. Gideon J. Davies 《Angewandte Chemie (International ed. in English)》2012,51(44):11171-11171
3.
Dr. Aloysius Siriwardena Kiran Kumar Pulukuri Pancham S. Kandiyal Dr. Saumya Roy Dr. Omprakash Bande Dr. Subhash Ghosh Dr. José Manuel Garcia Fernández Dr. Fernando Ariel Martin Dr. Jean‐Marc Ghigo Dr. Christophe Beloin Dr. Keigo Ito Dr. Robert J. Woods Dr. Ravi Sankar Ampapathi Dr. Tushar Kanti Chakraborty 《Angewandte Chemie (International ed. in English)》2013,52(39):10221-10226
4.
Polar oxide substrates for graphene growth: A first-principles investigation of graphene on MgO(111)
Kyung-Ah Min Jinwoo Park Junga Ryou Suklyun Hong Aloysius Soon 《Current Applied Physics》2013,13(5):803-807
Given the recent excitement over the truly two-dimensional carbon “super” material – graphene, there is now much effort and focus on the various possibilities of engineering the band gap of graphene for its device applications. One possible and promising route will be to grow graphene directly on some non-metallic substrates. In this paper, we address the atomic and electronic structure of various graphene structures on the polar MgO(111) using first-principles density-functional theory (DFT) calculations. We find that graphene generally interacts strongly with the O-terminated polar oxide surface, forming strong chemical bonds, inferred from both energetics and detailed density-of-states analysis. We compare our theoretical findings with available experimental results, offering a possible direction for future band gap engineering of graphene on such oxide substrates. 相似文献
5.
Thissa N. Siriwardena Alice Capecchi Bee‐Ha Gan Dr. Xian Jin Dr. Runze He Dr. Dengwen Wei Lan Ma Dr. Thilo Köhler Prof. Dr. Christian van Delden Dr. Sacha Javor Prof. Dr. Jean‐Louis Reymond 《Angewandte Chemie (International ed. in English)》2018,57(28):8483-8487
We used nearest‐neighbor searches in chemical space to improve the activity of the antimicrobial peptide dendrimer (AMPD) G3KL and identified dendrimer T7 , which has an expanded activity range against Gram‐negative pathogenic bacteria including Klebsiellae pneumoniae, increased serum stability, and promising activity in an in vivo infection model against a multidrug‐resistant strain of Acinetobacter baumannii. Imaging, spectroscopic studies, and a structural model from molecular dynamics simulations suggest that T7 acts through membrane disruption. These experiments provide the first example of using virtual screening in the field of dendrimers and show that dendrimer size does not limit the activity of AMPDs. 相似文献
6.
Vivek Verma Vibhav Pandey R.P. Aloysius R.K. Kotanala 《Physica B: Condensed Matter》2009,404(16):2309-2314
Lithium ferrite has been considered as one of the highly strategic magnetic material. Nano-crystalline Li0.5Fe2.5O4 was prepared by four different techniques and characterized by X-ray diffraction, vibrating sample magnetometer (VSM), transmission electron microscope (TEM) and Fourier transform infrareds (FTIR). The effect of annealing temperature (700, 900 and 1050 °C) on microstructure has been correlated to the magnetic properties. From X-ray diffraction patterns, it is confirmed that the pure phase of lithium ferrite began to form at 900 °C annealing. The particle size of as-prepared lithium ferrite was observed around 40, 31, 22 and 93 nm prepared by flash combustion, sol-gel, citrate precursor and standard ceramic technique, respectively. Lithium ferrite prepared by citrate precursor method shows a maximum saturation magnetization 67.6 emu/g at 5 KOe. 相似文献
7.
Vibhav Pandey R.P. Aloysius V.P.S. Awana R.K. Kotnala 《Journal of magnetism and magnetic materials》2009,321(14):2239-2244
The structural magnetic and magneto-transport properties of double perovskite system Ba2−xSrxFeMoO6 (0?x?1.0) prepared in bulk polycrystalline form are reported in this paper. X-ray diffraction analysis showed that samples are single phase and the lattice constants decreases with increase in the Sr content. The degree of Fe-Mo ordering has been found decreasing in the series with an increase in the Sr content. Parent compound Ba2FeMoO6 exhibits saturation magnetic moment value of 3.54 μB/f.u. at 85 K in a magnetic field of 6000 Oe. Temperature dependence of resistivity shows metallic behavior for all the samples. The magneto-resistance (MR) of the compound with x=0.4 is higher than that of the other samples. At room temperature this system shows a saturation magnetization value of 1.73 μB/f.u. and MR value of 7.08% (1 T). The observed variations in the structural and magnetic properties are attributed to the change of chemical pressure due to the substitution of Sr in place of Ba. The effect of antisite disorder (ASD) defects on magneto-transport properties is studied in more detail. 相似文献
8.
Rene G. Rodriguez Daniel J. V. Pulsipher Lisa D. Lau Endrit Shurdha Joshua J. Pak Michael H. Jin Kublinder K. Banger Aloysius F. Hepp 《Plasma Chemistry and Plasma Processing》2006,26(2):137-148
Thin films of CuInS2 were grown on various substrates at a temperature of 523 K from two metal-organic precursors using radiofrequency plasma enhanced chemical vapor deposition (PECVD). Two precursor molecules, with different solubility properties, were dissolved in appropriate solvents and sprayed into the plasma region in the PECVD chamber. The resulting films were examined for atomic composition, growth rate, crystalline orientation, and uniformity. Films made from each precursor differed in thickness, atomic composition, and crystallinity. The uniformity of the film was fairly good from near the edge to the center of the substrate, and evidence for a chalcopyrite-like structure was found in several samples deposited from one of the precursor molecules. 相似文献
9.
Thobhani S Ember B Siriwardena A Boons GJ 《Journal of the American Chemical Society》2003,125(24):7154-7155
Although complex modular proteins are encountered frequently in a variety of biological systems, their occurrence in biocatalysis has not been widely appreciated. Here, we describe that bacterial sialidases, which have both a catalytic and carbohydrate-binding domain, can hydrolyze polyvalent substrates with much greater catalytic efficiency than their monovalent counterparts. The enhancement of catalytic efficiency was due to a much smaller Michaelis constant and rationalized by a model in which the catalytic and lectin domains interact simultaneously with the polyvalent substrate, leading to an enhancement of affinity. Inhibition studies have shown that galactosides released by the action of the sialidase can act as the ligand for the lectin domain. This knowledge has been exploited in the design of a potent polyvalent inhibitor of the sialidase of Vibrio cholerae, which displayed exquisite selectivities for sialidases that have a lectin domain. 相似文献
10.
Mohammednoor Altarawneh Phillip V. Smith Eric M. Kennedy Aloysius Soon 《Applied Surface Science》2010,256(15):4764-1040
First-principles density functional theory and a periodic-slab model have been utilized to investigate the adsorption of a 2-chlorophenol molecule on a CuO(1 1 1) surface with a vacant Cu surface site, namely Cu2O(1 1 1)-CuCUS. Several vertical and flat orientations have been studied. All of these molecular configurations interact very weakly with the Cu2O(1 1 1)-CuCUS surface, an observation which also holds for clean copper surfaces and the Cu2O(1 1 0):CuO surface. Hydroxyl-bond dissociation assisted by the surface was found to be endoergic by 0.42-1.72 eV, depending predominantly on the position of the isolated H on the surface. In addition, the corresponding adsorbed 2-chlorophenoxy moiety was found to be more stable than a vacuum 2-chlorophenoxy radical by about 0.76 eV. Despite these predicted endoergicities, however, we would predict the formation of 2-chlorophenoxy radicals from gaseous 2-chlorophenol over the copper (I) oxide Cu2O(1 1 1)-CuCUS surface to be a feasible and important process in the formation of PCDD/Fs in the post-flame region where gas-phase routes are negligible. 相似文献