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611.
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614.
We examined the enantiomer separation with micelles and a micelle-like polymer made with trimethylammonium-terminated surfactants all of whose hydrocarbon chains contain hydrogen bonding valinediamide moieties in electrokinetic chromatography (EKC). The surfactants used were 3-(N-dodecanoyl-L-valylamino)-propyltrimethylammonium bromide (surfactant 1) and 6-(N-nonanoyl-L-valylamino)hexyl-trimethylammonium bromide (surfactant 2); the micelle-like polymer was derived from 3-(N-10-undecenoyl-L-valyl)aminopropyltrimethylammonium bromide (surfactant 3). N-Acylamino acids and their isopropyl esters were separated with enantiomers with the same configuration as the chiral surfactant and which were retained to a greater extent than the counterparts in micelles. The micellar hydrophobic environment, in which amides function as hydrogen bonding sites with solutes, and ceased micellar kinetic association-dissociation with polymerization are discussed. 相似文献
615.
Noboru Hamada 《Graphs and Combinatorics》1989,5(1):137-147
Recently, Hamada [5] characterized all {v
2 + 2v
1,v
1 + 2v
0;t,q}-min · hypers for any integert 2 and any prime powerq 3 wherev
l
= (q
l – 1)/(q – 1) for any integerl 0. The purpose of this paper is to characterize all {v
+ 1 + 2v
,v
+ 2v
– 1;t,q}-min · hypers for any integerst, and any prime powerq such thatt 3, 2 t – 1 andq 5 and to characterize all (n, k, d; q)-codes meeting the Griesmer bound (1.1) for the casek 3, d = q
k-1 – (2q
-1 +q
) andq 5 using the results in Hamada [3, 4, 5]. 相似文献
616.
617.
618.
[reaction: see text] New phosphine ligands possessing both axial chirality and a chirogenic phosphorus center were prepared from (R)-2-bromo-2'-N,N-(dimethylamino)-1,1'-binaphthyl (1) via a simple Li-halogen exchange protocol. The asymmetric vinylation of a ketone enolate with (R,R(P))-2-(tert-butylphenylphosphino)-2'-N,N-(dimethylamino)-1,1'-binaphthyl (2a) afforded the coupling product with good enantiomeric excess. 相似文献
619.
The basic characteristics of a sandwich injection molded product depend on the properties of the respective resins that comprise the skin and core layers, and the skin/core resin volume ratio. The characteristics of the core layer resin and the skin/core ratio in particular may vary depending on the injection molding conditions. This report considers the influences that the molding conditions such as injection speed, cylinder temperature, and mold temperature confer on the mechanical properties of the sandwich moldings. The study employed, skin/core resin combinations involving similar and dissimilar materials i.e. homopolymer PP/homopolymer PP and homopolymer PP/copolymer PP, respectively. It was demonstrated that core cylinder temperature and mold temperature could be used to adjust the mechanical properties of sandwich injection moldings. In the case of single material sandwich moldings, injection speed seemed to play no significant role, even though it was clearly demonstrated that core volume increases with injection speed. However, core injection speed plays a significant role in the dual material system by lowering or increasing the mechanical strength of moldings as the case may be. Thus, the dormant or active role of injection speed depending on the material system has been highlighted. 相似文献
620.
Yoko Sugawara Yoshiaki Hamada Akiko Y. Hirakawa Masamichi Tsuboi 《Chemical physics letters》1979,67(1):186-188
In the 0.12 cm?1 resolution infrared absorption spectrum of gaseous N-methylformamide, a progression of peaks with a spacing of about 2.6 cm?1 has been found in the 610-540 cm?1 region. This is assignable to a conformer with the CO and NH bonds cis to each other. 相似文献