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211.
Wee-Ong Siew Wai-Keat Lee Hin-Yong Wong Thian-Khok Yong Seong-Shan Yap Teck-Yong Tou 《Applied Physics A: Materials Science & Processing》2010,101(4):627-632
In the process of pulsed laser deposition of nickel (Ni) and ruthenium (Ru) thin films, the occurrence of phase explosion
in ablation was found to affect the deposition rate and enhance the optical emissions from the plasma plume. Faster thin-film
growth rates coincide with the onset of phase explosion as a result of superheating and/or sub-surface boiling which also
increased the particulates found on the thin-film surface. These particulates were predominantly droplets which may not be
round but flattened and also debris for the case of silicon (Si) ablation. The droplets from Ni and Ru thin films were compared
in terms of size distribution and number density for different laser fluences. The origins of these particulates were correlated
to the bubble and ripple formations on the targets while the transfer to the thin film surface was attributed to the laser-induced
ejection from the targets. 相似文献
212.
Kar T Liao MS Biswas S Sarkar S Dey K Yap GP Kreisel K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):882-886
A new octahedral chromium(III) complex having 2,2'-bipyridine as ligand system was synthesized in methanol. Single crystal X-ray diffraction analysis shows that it possesses non-stoichiometry in its anionic primary covalency. It has also been studied by elemental analyses, optical spectroscopy (UV-vis, IR) and magnetic susceptibility data. DFT calculations (with B3LYP functional and double-xi quality LANLDZ(D95V) basis set) were carried out to interpret the electronic and infrared spectra of the complex. The DFT optimized geometric structure for the complex is compared with the X-ray crystallographic data; the theory-experiment agreement is satisfactory. 相似文献
213.
214.
Patel DV Mihalcik DJ Kreisel KA Yap GP Zakharov LN Kassel WS Rheingold AL Rabinovich D 《Dalton transactions (Cambridge, England : 2003)》2005,(14):2410-2416
The first tris(mercaptoimidazolyl)borate complexes of gold, Au(Tm(tBu)) and (Tm(tBu))Au(PPh3), have been prepared and structurally characterized. Together with their copper and silver analogues M(Tm(tBu)) and (Tm(tBu))M(PPh3)(M = Cu, Ag), these compounds constitute the first two complete series of Tm(R) derivatives to be isolated for the coinage metals. In order to evaluate the steric and electronic effects of the bulky tert-butyl substituents in these species, comparative structural analyses with the known methyl-substituted analogue Ag(Tm(Me)) and various (Tm(Me))M(PR3) derivatives (M = Cu, Ag) are also presented. 相似文献
215.
The molecular structures of a number of 2,6-dimesitylphenyl-based (2,6-dimesitylphenyl = Dmp) complexes of the group 3 elements scandium and yttrium as well as of the lanthanide element ytterbium are reported. Reaction of 1 equiv of DmpLi with 1 equiv of MCl(3) (M = Sc, Yb, Y) in tetrahydrofuran at room temperature followed by crystallization from toluene/hexanes at -30 degrees C produces DmpMCl(2)(THF)(2) (M = Sc: 1; M = Yb: 2) and DmpMCl(2)(THF)(3) (M = Y: 3), respectively. The one-pot reaction of DmpLi with 1 equiv of YbCl(3) in tetrahydrofuran at room temperature followed by addition of 1 equiv of KO(t)Bu produces the heterobimetallic monoalkoxide complex DmpYb(THF)(O(t)Bu)(mu-Cl)(2)Li(THF)(2) (4), which was crystallized from toluene/tetrahydrofuran (20:1) at -30 degrees C. Crystal data for 1: monoclinic, P2(1)/n; T = 203 K; a = 10.178(3) A; b = 15.468(3) A; c = 20.132(5) A; beta = 101.85(3) degrees; V = 3102.0(17) A(3); Z' = 4; D(calcd) = 1.228 g cm(-3); R(1) = 5.89%. Crystal data for 2: monoclinic, P2(1)/n; T = 173 K; a = 10.2447(7) A; b = 15.5683(12) A; c = 20.0979(14) A; beta = 101.749(4) degrees; V = 3238.3(5) A(3); Z' = 4; D(calcd) = 1.485 g cm(-3); R(1) = 4.32%. Crystal data for 3: monoclinic, P2(1)/n; T = 203 K; a = 15.950(3) A; b = 11.865(2) A; c = 18.254(3) A; beta = 92.323(3) degrees; V = 3451.9(10) A(3); Z' = 4; D(calcd) = 1.327 g cm(-)(3); R(1) = 4.43%. Crystal data for 4: triclinic, P1; T = 193 K; a = 10.2252(2) A; b = 11.3497(2) A; c = 18.5814(2) A; alpha = 98.7353(6) degrees; beta = 102.8964(6) degrees; gamma = 94.8058(5) degrees; V = 2062.09(5) A(3); Z' = 2; D(calcd) = 1.375 g cm(-3); R(1) = 4.56%. The molecular structures of 1-3 feature monomeric complexes with distorted trigonal-bipyramidal (1 and 2) or octahedral (3) coordination geometry about the metal atom, with the two chlorine atoms occupying the axial positions. 4 represents the first example of an alkoxide derivative of a terphenyl lanthanide complex. The molecular structure of the ate complex 4 exhibits a heavily distorted trigonal-bipyramidal coordination polyhedron about the ytterbium atom, with one of the mu-chlorine atoms and the oxygen atom of the tetrahydrofuran ligand representing the axial positions of the trigonal-bipyramidal arrangement. A terminal alkoxide ligand is another main feature of the molecular structure of complex 4. 相似文献
216.
Reaction of the dinuclear [(CH2SiMe3)(mu-CH2SiMe3)Mn(THF)]2 (1) with an equivalent amount of 1,1-dipyrrolylcyclohexane afforded two compounds depending on the solvent employed. Reaction carried out in THF afforded the dinuclear ([1,1-(mu-C4H3N)(C4H3N)C6H10]Mn(THF)2)2.2(THF) (2) while reaction in toluene yielded the octanuclear and cyclic cluster ([1,1-(mu,eta1:eta5-C4H3N)2C6H10]Mn)8.4(toluene) (3). The magnetism in all three cases is dominated by intramolecular antiferromagnetic exchange with strong coupling in 1 (J=-85 cm(-1)), and in 2 (J=-23.2 cm(-1)), whereas substantially weaker coupling through the sigma/pi-bonded dipyrrolide bridges (J=-3.3 cm(-1)) was observed within the cyclic and octameric 3. 相似文献
217.
Interference effect in scattering loss of high-index-contrast planar waveguides caused by boundary reflections 总被引:1,自引:0,他引:1
Schmid JH Delâge A Lamontagne B Lapointe J Janz S Cheben P Densmore A Waldron P Xu DX Yap KP 《Optics letters》2008,33(13):1479-1481
We present theoretical and experimental results on an interference effect caused by boundary reflections on the optical scattering loss in high-index-contrast planar waveguides. Analytical expressions for the polarization-dependent scattering loss are derived using a surface Green's function. For high-index-contrast waveguides of submicrometer dimensions a significant deviation from accepted theory arises, including scattering loss suppression owing to a thin-film interference effect. Our theoretical predictions are confirmed by loss measurements on silicon-on-insulator channel waveguides. 相似文献
218.
Barry ST Gordon PG Ward MJ Heikkila MJ Monillas WH Yap GP Ritala M Leskelä M 《Dalton transactions (Cambridge, England : 2003)》2011,40(37):9425-9430
A new homoleptic sublimable indium(III) guanidinate, (In[(N(i)Pr)(2)CNMe(2)](3) (1), was synthesized from a facile high-yield procedure. Compound 1 crystallized is a P1 space group; a = 10.5989(14) ?, b = 11.0030(15) ?, c = 16.273(2) ?, α = 91.190(2)°, β = 96.561(2)°, γ = 115.555(2)°; R = 3.50%. Thermogravimetric analysis showed 1 to produce elemental indium as a residual mass. Thermolysis in a sealed NMR tube showed carbodiimide and protonated dimethyl amine by (1)H NMR. Chemical vapour deposition experiments above 275 °C with air as the reactant gas showed 1 to readily deposit cubic indium oxide with good transparency. 相似文献
219.
Mechanistic Study of a Switch in the Regioselectivity of Hydroheteroarylation of Styrene Catalyzed by Bimetallic Ni–Al through CH Activation 下载免费PDF全文
Dr. Wen‐Ching Chen Ying‐Chieh Lai Wei‐Chun Shih Ming‐Shiuan Yu Dr. Glenn P. A. Yap Prof. Dr. Tiow‐Gan Ong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(26):8099-8105
We previously reported a highly efficient protocol for bimetallic Ni–Al‐catalyzed hydroheteroarylation of styrene with benzimidazole based on C?H bond activation. We have now delineated the mechanism of this process, providing a rationale for an observed switch in regioselectivity in the presence of the Lewis acid, AlMe3. The present mechanistic study gives insights for the rational development of catalysts that exhibit required linear/branched selectivity. 相似文献
220.
S.S. Yap 《Applied Surface Science》2007,253(24):9521-9524
In pulsed Nd:YAG laser ablation of highly oriented pyrolytic graphite (HOPG) at 10−6 Torr, diamond-like carbon (DLC) are deposited at laser wavelengths of 1064, 532, and 355 nm on substrates placed in the target-plane. These target-plane samples are found to contain varying sp3 content and composed of nanostructures of 40-200 nm in size depending on the laser wavelength and laser fluence. The material and origin of sp3 in the target-plane samples is closely correlated to that in the laser-modified HOPG surface layer, and hardly from the backward deposition of ablated carbon plume. The surface morphology of the target-plane samples shows the columnar growth and with a tendency for agglomeration between nanograins, in particular for long laser wavelength at 1064 nm. It is also proposed that DLC formation mechanism at the laser-ablated HOPG is possibly via the laser-induced subsurface melting and resolidification. 相似文献