Browsing by Author "Wu, SH"

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Synthesis of calix[4]arenes with four different "lower rim" substituents
(1999-04-16)
Shu, CM
;
Chung, WS
;
Wu, SH
;
Ho, ZC
;
Lin, LG
Calix[4]arenes with four different "lower rim" substituents were synthesized following six-step sequences. The first alkyl group (R-1) was introduced using R1X and CH3ONa, and then reaction with R2X and K2CO3 led to the introduction of a second alkyl group (R-2) at the 3-position. Benzoate was introduced as a protecting group at the 1,3-O-disubstituent stage and was removed under basic conditions after the incorporation of the third alkyl group (R-3) With R3X and NaH, The final alkyl group (R-4) was introduced with R4X and NaH to give the chiral title compounds.
Vortex domain wall depinning by polarized current in submicron half-ring wires
(2006-04-15)
Chen, YS
;
Cheng, KW
;
Yu, C
;
Lee, SF
;
Chen, DC
Domain wall pinning force in the junctions (corners), with different shapes of square, semicircle, or triangle, of half-ring in-series wires is considered to study the current injection induced wall movements. This geometry has less thermal activation at the region of domain wall nucleation in contrast to notch structures. The wires with square corners have the largest domain pinning force to resist polarized current-induced magnetization reversal, judging from the largest slope in the current-field dependence (Delta I/Delta H=0.274). (C) 2006 American Institute of Physics.