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81.
F. M. El-Hossary N. Z. Negm S. M. Khalil A. M. Abed?El-Rahman M. Raaif S. M?ndl 《Applied Physics A: Materials Science & Processing》2010,99(2):489-495
Carbonitriding of AISI 304 austenitic stainless steel was performed at a plasma-processing power of 450 W using inductively
coupled radio frequency (rf) plasma in a gas mixture of 50% N2 and 50% C2H2. The rate of carbonitriding, microhardness, phase structure of the compound layer, surface microstructure and cross-section
morphology were studied before and after the annealing process. At the annealing temperature up to 800°C, the microhardness
values of the compound zones decrease, while the associated values of the diffused zones increase. Little change was found
in the thickness of the compound and diffused zones when the carbonitrided samples were annealed up to 400°C. However, at
a higher annealing temperature, the thicknesses of both zones increase. The γ-Fe austenite is the main crystalline phase that can be detected by X-ray diffraction. As the annealing temperature increases
up to 500°C, X-ray spectra show α-Fe and Fe5C2 phases. Nitrogen diffuses more deeply from the near surface to the interior of the treated sample as the annealing temperature
increases up to 800°C and this might explain the extent of carbonitrided thickness and the enhanced microhardness of the diffused
zone. 相似文献
82.
Mahmood Z Azam M Mushtaq A Kausar R Kausar S Gilani SR 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(2):445-452
The infrared spectra of pure Mn(CO)(5)X in the region 4000-400 cm(-1) has been obtained in the vapour phase. The observed spectrum has been analyzed to distinguish the fundamental frequencies, the rotational-vibrational and structure, and overtone and combination frequencies. The assignment of the observed vapour phase frequencies to the fundamental modes of vibration has been made on C(4V) symmetry. The weak peaks due to XMn(CO)(4)((13)CO) molecules have been measured and assigned for all molecules. This study provides a comprehensive comparison of these compounds, with all of these data the assignment of frequencies is reviewed and a set of quite unambiguous assignments made. The significant finding in this regards are that, it is not necessary to assume lower than C(4V) symmetry for XMn(CO)(5) as has been done in previous consideration of some infrared spectrum of these compounds. 相似文献
83.
Tanveer Hussain Bokhari A. Mushtaq Islam Ullah Khan 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(2):389-398
In this work, sorption of Ni(II) from aqueous solution to goethite as a function of various water quality parameters and temperature
was investigated. The results indicated that the pseudo-second-order rate equation fitted the kinetic sorption well. The sorption
of Ni(II) to goethite was strongly dependent on pH and ionic strength. A positive effect of HA/FA on Ni(II) sorption was found
at pH < 8.0, whereas a negative effect was observed at pH > 8.0. The Langmuir, Freundlich, and D-R models were applied to
simulate the sorption isotherms at three different temperatures of 293.15 K, 313.15 K and 333.15 K. The thermodynamic parameters
(ΔH
0, ΔS
0 and ΔG
0) were calculated from the temperature dependent sorption, and the results indicated that the sorption was endothermic and
spontaneous. At low pH, the sorption of Ni(II) was dominated by outer-sphere surface complexation or ion exchange with Na+/H+ on goethite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. 相似文献
84.
Alina Botvinik Abed Al Aziz Quntar Avri Rubinstein Morris Srebnik 《Journal of organometallic chemistry》2009,694(20):3349-3352
Boryl zirconacycopropenes stabilized with tributylphosphine react with alkynes (terminal and internal) to give predominately 2-boryl-1,3-butadienes, 5, in 40-81% isolated yields. Products 5 are accompanied by 4-boryl-1,3-butadienes in 7-23% when terminal alkynes are inserted. However, the use of an internal alkyne (3-hexyne) gave predominantly 6c. 相似文献
85.
Di- or tri-substituted vinylphosphonates, 2-5, can be obtained in a highly regio- and stereoselective manner from 1-alkynylphosphonates, by manipulation of Ti(O-i-Pr)4/2i-PrMgCl. 相似文献
86.
Affoune AM Yamada A Umeda M 《Langmuir : the ACS journal of surfaces and colloids》2004,20(17):6965-6968
Surface morphology modification of the Nafion 117 membrane has been investigated by atomic force microscopy. The effects of water and methanol on the topography and structure of the surface were studied using the contact and tapping atomic force microscopy modes. Nafion topography considerably changes when samples absorb water. However, samples stored in methanol are characterized by flat surfaces. Surface modification was linked to an expansion phenomenon during the swelling of Nafion by solvents. Tapping-mode phase images showed that ionic and cluster domains are distinguishable from the surface of samples impregnated either in water or methanol. 相似文献
87.
Etienne Gaudin Jean‐Pierre Chaminade Ahmed El Abed Jacques Darriet 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1004-1005
The new oxychloride InTeO3Cl was synthesized from a mixture of In2O3, InCl3 and TeO2. Its structure has been determined from single‐crystal X‐ray diffraction data. The structure is composed of layers separated by a van der Waals gap. The layers consist of edge‐sharing chains of [InO4Cl2] octahedra linked through [TeO3] trigonal pyramids. No free Cl atoms are located between the layers. 相似文献
88.
The kinetics of thermal dehydration of bis-(4-aminosalicylato)-diaquo complexes of VO(II), Cu(II), Ni(II), Co(II), Fe(II) and Mn(II), were studied. The activation energies and other kinetic parameters have been evaluated. The observed kinetic parameters indicate a first-order reaction. The activation energy of the thermal dehydration decreases in the order: VO(II) > Cu(II) > Co(II) > Ni(II) > Fe(II) > Mn(II), which is also the order for the covalency in the MO bonds. 相似文献
89.
90.
An easy, one-pot transformation of Baylis-Hillman adducts into carbamates of unsaturated β-amino acids, for example, 2-(aryl(methoxycarbonylamino)methyl)acrylic acid methyl esters 7 and 2-(methoxycarbonyl aminomethyl)-3-arylacrylic acid methyl esters 8 via reaction with the Burgess reagent is described. 相似文献