Preferential Growth of the Cobalt (200) Facet in Co@N–C for Enhanced Performance in a Fenton-like Reaction

ACS Catalysis ◽  
2021 ◽  
pp. 5532-5543
Author(s):  
Lipeng Wu ◽  
Bin Li ◽  
Yang Li ◽  
Xiaobin Fan ◽  
Fengbao Zhang ◽  
...  
Keyword(s):  
Preferential Growth

scholarly journals Allelic Exchange and Mutant Selection Demonstrate that Common Clinical embCAB Gene Mutations Only Modestly Increase Resistance to Ethambutol in Mycobacterium tuberculosis

2009 ◽  
Vol 54 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Hassan Safi ◽  
Robert D. Fleischmann ◽  
Scott N. Peterson ◽  
Marcus B. Jones ◽  
Behnam Jarrahi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
In Vitro Selection ◽  
Gene Mutations ◽  
Wild Type ◽  
Mutant Selection ◽  
Preferential Growth ◽  
Allelic Exchange ◽  
High Level ◽  
Isogenic Mutants

ABSTRACT Mutations within codon 306 of the Mycobacterium tuberculosis embB gene modestly increase ethambutol (EMB) MICs. To identify other causes of EMB resistance and to identify causes of high-level resistance, we generated EMB-resistant M. tuberculosis isolates in vitro and performed allelic exchange studies of embB codon 406 (embB406) and embB497 mutations. In vitro selection produced mutations already identified clinically in embB306, embB397, embB497, embB1024, and embC13, which result in EMB MICs of 8 or 14 μg/ml, 5 μg/ml, 12 μg/ml, 3 μg/ml, and 4 μg/ml, respectively, and mutations at embB320, embB324, and embB445, which have not been identified in clinical M. tuberculosis isolates and which result in EMB MICs of 8 μg/ml, 8 μg/ml, and 2 to 8 μg/ml, respectively. To definitively identify the effect of the common clinical embB497 and embB406 mutations on EMB susceptibility, we created a series of isogenic mutants, exchanging the wild-type embB497 CAG codon in EMB-susceptible M. tuberculosis strain 210 for the embB497 CGG codon and the wild-type embB406 GGC codon for either the embB406 GCC, embB406 TGC, embB406 TCC, or embB406 GAC codon. These new mutants showed 6-fold and 3- to 3.5-fold increases in the EMB MICs, respectively. In contrast to the embB306 mutants, the isogenic embB497 and embB406 mutants did not have preferential growth in the presence of isoniazid or rifampin (rifampicin) at their MICs. These results demonstrate that individual embCAB mutations confer low to moderate increases in EMB MICs. Discrepancies between the EMB MICs of laboratory mutants and clinical M. tuberculosis strains with identical mutations suggest that clinical EMB resistance is multigenic and that high-level EMB resistance requires mutations in currently unknown loci.

Ion Bombardment Effect on the Hardness of Ti(C,N,O) Films Prepared by Ion Beam Controlled Deposition (IBCD)

1992 ◽  
Vol 279 ◽  
Author(s):  
Chen Youshan ◽  
Sun Yilin ◽  
Zhang Fumin ◽  
Mou Haichuan ◽  
Tao Wei ◽  
...  
Keyword(s):  
Film Formation ◽  
Ion Beam ◽  
Ion Bombardment ◽  
Advanced Technology ◽  
Preferential Growth ◽  
Ion Energy ◽  
Lattice Constants ◽  
Film Hardness ◽  
Pure Compounds ◽  
Controlled Deposition

Ion beam controlled deposition (IBCD) or ion beam assisted deposition (IB AD) of Ti(C,N,O) films has been investigated much in the last decade for both the advantage of this advanced technology and the promising properties of such materials. Ti(C,N,O) films are various solid solutions of interstitial compounds TiC, TiN and TiO of F.C.C structure with lattice constants lying between the values of the pure compounds. Some content of oxygen improves their wear resistance due to the lower fn;e enthalpies of such films in comparison with pure TiC and TiN films [1]. Many so-synthesizcd titanium carbide and titanium nitride films reported in published papers were actually of this sort as they often had more or less oxygen content from residual gas in vacuum. A number of papers were contributed to depict the texture and composition dependence of film on the arrival ratio of assisting ions versus deposited atoms (AR) as well as their mechanical properties [2–6]. However, the film formation mechanism in IBCD isn't quite clear yet, especially for cases with assisting ion energy of several to tens of keV. During a course to synthesize Ti(C,N,O) films by IBCD with the two beam technique, datum were accumulated. Based on a part of it, a previous paper on ion beam governed preferential growth in IBCD has been published [7]. This paper was aimed to search for the origin of ion bombardment effect on film hardness.

Crystallization behavior, Al-Ce intermetallic formation, and microstructure refinement of near-eutectic Al–Si alloys by rare-earth element additions

2020 ◽  
Vol 111 (11) ◽  
pp. 938-952
Author(s):  
Bo Chi ◽  
Zhiming Shi ◽  
Cunquan Wang ◽  
Liming Wang ◽  
Hao Lian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Crystallization Behavior ◽  
Earth Element ◽  
Microstructural Refinement ◽  
Preferential Growth ◽  
Intermetallic Formation ◽  
The Matrix

Abstract Near-eutectic Al-Si alloys have low strength and high brittleness because of the presence of many eutectic b-Si flakes, needle-like Al-Fe-Si intermetallics, and coarse α-Al grains. This study disclosed the effects of cerium-rich RE (rare earth) element modification on orientation characters of crystals, formation of Al-Ce compounds, and microstructural refinement to improve the microstructure and mechanical properties of the alloys. The RE addition depressed preferential growth along the close-packed and/or sub-closepacked planes and promoted growth along the non-closepacked planes, in which La and other elements were dissolved into needle-like Al11Ce3 phase. When the temperature decreased, Al11Ce3 was preferentially crystallized from the melts and then devitrified by attaching to the surface of β-Al5FeSi needles. Moreover, many small Al11Ce3 particles were precipitated in the matrix and on the Si surface by a T6 heat treatment. Eutectic β-Si phases were constructed into discontinuous networks, short rods, and even particles by RE additions, which were further transformed into fine nodules following the T6 treatment. α-Al grains and primary β-Al5FeSi needles were simultaneously refined. The addition of 1.0 wt.% REs and subsequent T6 treatment yielded the highest tensile strength, elongation, and hardness of the alloy.

Preferential Growth of Carbon Nanotubes/Nanofibers Using Lithographically Patterned Catalysts

2001 ◽  
Vol 675 ◽  
Author(s):  
K. B. K. Teo ◽  
M. Chhowalla ◽  
G. A. J. Amaratunga ◽  
W. I. Milne ◽  
G. Pirio ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Amorphous Carbon ◽  
Deposition Process ◽  
High Yield ◽  
Full Potential ◽  
Carbon Nanofibres ◽  
Preferential Growth ◽  
Plasma Decomposition

ABSTRACTIn order to utilise the full potential of carbon nanotubes/nanofibers, it is necessary to be able to synthesize well aligned nanotubes/nanofibres at desired locations on a substrate. This paper examines the preferential growth of aligned carbon nanofibres by PECVD using lithographically patterned catalysts. In the PECVD deposition process, amorphous carbon is deposited together with the nanotubes due to the plasma decomposition of the carbon feed gas, in this case, acetylene. The challenge is to uniformly nucleate nanotubes and reduce the unwanted amorphous carbon on both the patterned and unpatterned areas. An etching gas (ammonia) is thus also incorporated into the PECVD process and by appropriately balancing the acetylene to ammonia ratio, conditions are obtained where no unwanted amorphous carbon is deposited. In this paper, we demonstrate high yield, uniform, ‘clean’ and preferential growth of vertically aligned nanotubes using PECVD.

Morphological Characterization of Shape-Controlled TiO2 Anatase through XRPD Analysis

2016 ◽  
Vol 230 (9) ◽  
Author(s):  
Mauro Coduri ◽  
Michela Maisano ◽  
Maria Vittoria Dozzi ◽  
Elena Selli
Keyword(s):  
Morphological Characterization ◽  
Morphological Investigation ◽  
X Ray Diffraction ◽  
Preferential Growth ◽  
Rietveld Refinements ◽  
X Ray ◽  
Tio2 Anatase ◽  
Shape Controlled ◽  
Scherrer Equation

AbstractPreferential growth of anatase crystallites along different directions is known to deeply affect their photocatalytic properties, especially with respect to the exposure of the reactive {001} facets. Its extent can be easily quantified through simple geometric calculations, on the basis of crystal sizes extracted for specific directions by means of X-Ray Diffraction data analysis. Nevertheless, the actual results depend on the method employed for such a quantification. Here we report on a comparative morphological investigation, performed by employing the Scherrer equation and the line profile from Rietveld refinements, on shape-controlled anatase photocatalysts produced by employing HF as capping agent. Compared to the Rietveld-based method, the use of the Scherrer equation produces a systematic underestimation of crystallite dimensions, especially concerning the [100] direction, which in turn causes the percentage of exposed {001} crystal facets to be underestimated. Neglecting instrumental-related effects may further reduce the estimate.

scholarly journals Preferential Growth of δ-Bi2O3 Layers on the {11-20} Facets of ZnO Nanowires

2013 ◽  
Vol 19 (S2) ◽  
pp. 1516-1517 ◽  
Author(s):  
J. Xu ◽  
J. Liu
Keyword(s):  
Zno Nanowires ◽  
Preferential Growth

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Comparison of Cvd and Pvd Tungsten for Gigabit-Scale Dram Interconnections

1996 ◽  
Vol 427 ◽  
Author(s):  
John M. Drynan ◽  
Kuniaki Koyama
Keyword(s):  
Sheet Resistance ◽  
Crystal Orientation ◽  
Total Thickness ◽  
Preferential Growth ◽  
Materials Properties ◽  
Lower Resistance

AbstractThe characteristics of blanket CVD-W and PVD-W films with and without TiN/Ti underlayers have been investigated in terms of both materials properties such as resistance, stress, morphology, crystallinity, and composition, and prospective applications such as for DRAM bit line interconnections. The presence of a TiN underlayer has been found to induce preferential growth of dominant W (110) crystal orientation for both CVD-W and PVD-W whereas absence of TiN results in a W film of mixed W (110), (200), and (211) crystallites. Sheet resistance measurements of both blank films and conductor lines have shown that a 200nm-thick PVD-W film yields a lower resistance than a similar film with TiN underlayer and hence larger total thickness. This correspondence of W (110) intensity with resistance implies that reduction of the (110) oriented crystallites within a W film can yield lower resistances. Thus, by elimination of the TiN/Ti underlayer, monolayer PVD-W or CVD-W with a PVD-W underlayer can be effectively adapted to quarter-micron conductors for bit line interconnections and related structures in DRAM memory and other ULSI devices.

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