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11.
Let R be a ring with involution *. We consider R as a ring equipped with a new product r s = rs + sr*. The relationship between (ordinary) ideals of R and right ideals of R with respect to the product is studied.AMS Subject Classification (2000): 16W10, 16D25 相似文献
12.
Yumeng Xi Trevor W. Butcher Jing Zhang John F. Hartwig 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(2):786-790
We report the regioselective and enantioselective formal hydroamination of unsymmetrical internal alkenes catalyzed by a copper catalyst ligated by DTBM‐SEGPHOS. The regioselectivity of the reaction is controlled by the electronic effects of ether, ester, and sulfonamide groups in the homoallylic position. The observed selectivity underscores the influence of inductive effects of remote substituents on the selectivity of catalytic processes occurring at hydrocarbyl groups, and the method provides direct access to various 1,3‐aminoalcohol derivatives with high enantioselectivity. 相似文献
13.
A new radiochemical scheme for the quantitative isolation of Ga, Sc, Hf and La, based on ion exchange and extraction chromatography,
was devised, Ga and Sc were selectively retained on a Dowex 50WX2 [H+] column from 10 M HBr at 50°C. Ga was then eluted with ethyl acetate 0.25M in HBr, and scandium with 4M HBr. Hf was separated
from 10M HBr at 75°C on a Kel-F column impregnated with tri-n-octylphosphine oxide (TOPO). The lanthamm fraction, after evaporation
to dryness, was purified by ion-exchange chromatography in the system: Dowex 50WX8 [H+]−HCl. The effect of accompanying elements, and also the differences in the mechanism of uptake by the resin of various elements
from concentrated HBr solution are briefly discussed. The scheme has been used for the determination of these four elements
in refractory materials by activation analysis. As this procedure assured practically quantitative isolation of Ga, Sc, Hf
and La, the addition of carriers and determination of chemical yield were unnecessary. The radiochemical purities of the respective
fractions were as a rule high, and the measurements were performed by NaI(Tl) spectrometry. The detection limits were of the
order of fractions of ppm, and could be considerably improved if necessary by increasing the counting time and sample weight. 相似文献
14.
Ferrocene-terminated trans-Ru(dppm)2 (dppm=Ph2PCH2pph2)-containing molecular wires with alligator clips were prepared.They are suitable for self-assembly on gold electrode to investigate the influence of metal incorporation on the electron transportation property of the molecular wires. 相似文献
15.
The main purpose of this paper is to prove the following result. Let R be a prime ring of characteristic different from two and let T : R → R be an additive mapping satisfying the relation T(x
3) = T(x)x
2 − xT(x)x + x
2
T(x) for all x ∈ R. In this case T is of the form 4T(x) = qx + xq, where q is some fixed element from the symmetric Martindale ring of quotients. This result makes it possible to solve some functional
equations in prime rings with involution which are related to bicircular projections. 相似文献
16.
Ke D Wang X Yang Q Niu Y Chai S Chen Z An X Shen W 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14112-14117
The interaction between dodecyltrimethylammonium bromide (DTAB) and curcumin has been studied in pH 5.0 sodium phosphate buffer using absorption and fluorescence measurements. With increasing DTAB concentration (C(DTAB)) from 0 to 20 mM, the absorption peak of curcumin at 430 nm, corresponding to the conjugated structure of curcumin, first weakens gradually into a shoulder but increases back into one peak with much higher absorption intensity. On the contrary, as C(DTAB) increases, the initial small absorption shoulder of curcumin at 355 nm, corresponding to the feruloyl unit of curcumin, first increases gradually into a clear peak but decreases back into one shoulder until almost disappeared finally. By remaining at nearly the same wavelength, the fluorescence of curcumin first decreases at C(DTAB) lower than 5 mM and then increases gradually up to C(DTAB) = 10 mM, which is followed by sharp increases of fluorescence intensity with marked blue-shifts at higher C(DTAB). The values of anisotropy and microviscosity of curcumin obtained from the fluorescence polarization technique also showed pronounced changes at different surfactant concentrations. The interaction mechanisms of DTAB with curcumin have been presented at low, intermediate, and high surfactant concentrations, which is relating to interaction forces, surfactant aggregations, as well as structural alterations of curcumin. 相似文献
17.
An alternative approach to the study of Jordan ideals in associative algebras is considered. The same method can be used when analogous questions in graded algebras are treated. 相似文献
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