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W H Newsome J B Shields 《International journal of environmental analytical chemistry》1981,10(3-4):295-304
A radioimmunoassay was developed capable of determining Aroclor 1260 in milk at levels of from 20 to 80 ppb and in blood from 2 to 16 ppb. The values obtained by radioimmunoassay correlate well with those determined by gas-liquid chromatography (r2 = 0.96 for milk and 0.99 for blood) but were lower. Antiserum was produced in rabbits and was specific for 2,2',4,4',5,5'-hexachlorobiphenyl. It cross-reacted with congeners and isomers in Aroclor 1254 and 1260 to the extent that a 20% decrease in binding was observed with 0.1 ng of either mixture. The method requires preliminary cleanup of the extract on alumina and utilizes 25% dimethyl sulfoxide in the assay medium to promote solubilization of the substrates. 相似文献
125.
Skew products of Bernoulli shifts with rotations 总被引:1,自引:0,他引:1
This paper investigates certain skew products of Bernoulli shifts with rotations or permutations, and shows that these transformations,
if weak mixing, are also Bernoulli.
This work was partially supported by the U. S. Air Force Office of Scientific Research under contract F44620-C-0063, P001,
and by National Science Foundation under grant GP 21509.
This work was partially supportedby the National Science Foundation under grants GP 21509 and GJ-776. 相似文献
126.
Alavi-Harati A Alexopoulos T Arenton M Arisaka K Averitte S Barbosa RF Barker AR Barrio M Bellantoni L Bellavance A Belz J Bergman DR Blucher E Bock GJ Bown C Bright S Cheu E Childress S Coleman R Corcoran MD Corti G Cox B Erwin AR Ford R Glazov A Golossanov A Graham G Graham J Halkiadakis E Hamm J Hanagaki K Hidaka S Hsiung YB Jejer V Jensen DA Kessler R Kobrak HG LaDue J Lath A Ledovskoy A McBride PL Mikelsons P Monnier E Nakaya T Nelson KS Nguyen H O'Dell V Pordes R Prasad V Qi XR Quinn B 《Physical review letters》2002,89(21):211801
The recent discovery of a large CP violating asymmetry in KL-->pi+pi-e+e- mode has prompted us to seach for the associated KL-->pi 0 pi 0 e+e- decay mode in the KTeV-E799 experiment at Fermilab. In 2.7 x 10(11) K(L) decays, one candidate event has been observed with an expected background of 0.3 event, resulting in an upper limit for the KL-->pi 0 pi 0 e+e- branching ratio of 6.6 x 10(-9) at the 90% C.L. 相似文献
127.
We give a sufficient condition for a codimension one, transversely orientable foliation of a closed 3-manifold to have the property that any foliation sufficiently close to it be -covered. This condition can be readily verified for many examples. Further, if an -covered foliation has a compact leaf , then any transverse loop meeting lifts to a copy of the leaf space, and the ambient manifold fibers over with as fiber.
128.
Ohne ZusammenfassungThe work of the first author was partially supported by the United States Air Force Office of Scientific Research Grants AF OSR 460-63 and 460-67. 相似文献
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We establish that routine B3LYP and MP2 methods give qualitatively wrong conformations for flexible organic systems containing pi systems and that recently developed methods can overcome the known inadequacies of these methods. This is illustrated for a molecule (a conformer of the Tyr-Gly dipeptide) for which B3LYP/6-31+G(d) and MP2/6-31+G(d) geometry optimizations yield strikingly different structures [Mol. Phys. 2006, 104, 559-570]: MP2 predicts a folded "closed-book" conformer with the glycine residue located above the tyrosine ring, whereas B3LYP predicts a more open conformation. By employing different levels of theory, including the local electron correlation methods LMP2 (local MP2) and LCCSD(T0) (local coupled cluster with single, double, and noniterative local triple excitations) and large basis sets (aug-cc-pVnZ, n=D, T, Q), it is shown that the folded MP2 minimum is an artifact caused by large intramolecular BSSE (basis set superposition error) effects in the MP2/6-31+G(d) calculations. The B3LYP functional gives the correct minimum, but the potential energy apparently rises too steeply when the glycine and tyrosine residues approach each other, presumably due to missing dispersion effects in the B3LYP calculations. The PWB6K and M05-2X functionals, designed to give good results for weak interactions, remedy this to some extent. The reduced BSSE in the LMP2 calculations leads to faster convergence with increasing basis set quality, and accurate results can be obtained with smaller basis sets as compared to canonical MP2. We propose LMP2 as a suitable method to study interactions with pi-electron clouds. 相似文献