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1.
A method for the determination of 5 triazine herbicides and 12 degradation products in environmental water samples using liquid chromatography-electrospray ionization mass spectrometry (LC/ESI/MS) has been developed. The pesticides in water were extracted with two types of solid phase: a styrene-divinylbenzene copolymer and a graphitized carbon black. Desorption solvents for the extracted compounds were acetone for the styrene-divinylbenzene copolymer and methanol for the graphitized carbon black. Overall recoveries from ground water and river water ranged from 73% to 111%. The limits of detection (LODs) were 0.2 to 28 ng l(-1). This method was applied to several ground water samples. 相似文献
2.
Hyperfine Interactions - Sm2(Co1?x Fe x )17 alloys form the basis of a new class of permanent magnets. We have investigated these materials with57Fe Mössbauer spectroscopy. Alloys... 相似文献
3.
K. Nagamine 《Hyperfine Interactions》1991,65(1-4):1149-1158
The proposed next major science project in Japan, the high intensity 1 GeV proton accelerator with unique beam characteristics,
is described here. It will supply a proton beam of more than 100 μA in either de mode or sharply pulsed mode (down to 10 ns),
using a specially designed time structure conversion ring. The beam will be used for keV μ+ generation at the production target, MeV surface μ+ production and 10 MeV decay μ+ and μ− production, as well as a possible slow μ− production. All of these unique muon beams will be developed for the next generation of μSR experiments. With the development
of the keV μ+ source particularly in mind, a pilot station is now under construction at UT-MSL/KEK. Possible new μSR experiments are also
reviewed. 相似文献
4.
M. K. Kubo Y. Sakai T. Tominaga K. Nishiyama K. Nagamine 《Journal of Radioanalytical and Nuclear Chemistry》1989,136(1):61-66
Diamagnetic muon yields /PD/ in various metal acetylacetonates were measured at room temperature by the muon spin rotation technique. We have found a clear difference in PD between complexes of typical elements and those of transition elements. We suggest that partially filled inner orbitals play some important role in determining the diamagnetic yield in these complexes. 相似文献
5.
6.
Kuniaki Tatsuta Yoshiya Amemiya Yoshinobu Kanemura Hideaki Takahashi Mitsuhiro Kinoshita 《Tetrahedron letters》1982,23(33):3375-3378
Tylosin has been synthesized byregio- and stereoselective introduction of the amino disaccharide moiety and D-mycinose onto the previously synthesized 16-membered-ring aglycone. 相似文献
7.
8.
Fujii H Hirano N Uchiro H Kawamura K Nagase H 《Chemical & pharmaceutical bulletin》2004,52(6):747-750
7beta-Carbamoyl-4,5alpha-epoxymorphinans 5 were stereoselectively synthesized from the 7alpha-carboxylate intermediate 3 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and amines under reflux conditions in mesitylene via a novel and reactive gamma-lactone 7. These were the first examples of the stereoselective syntheses of 7beta-substituted 4,5alpha-epoxymorphinans. The mechanism of the reaction process was elucidated as follows: 1) epimerization of 7alpha-carboxylate 3, 2) intramolecular lactonization of 7beta-carboxylate 6, and 3) aminolysis of the resultant gamma-lactone 7. The aminolysis of the isolated reactive gamma-lactone 7 with allylamine and the alcoholysis with MeOH in the presence of NaBH(4) proceeded at room temperature. The gamma-lactone 7 can be a useful intermediate for the preparation of 7beta-substituted 4,5alpha-epoxymorphinans that would be potent selective delta opioid receptor ligands. The stereoselective syntheses of the 7alpha-carbamoyl-4,5alpha-epoxymorphinans 9 from 7alpha-carboxylate 3 via 7alpha-carboxylic acid were also successful. 相似文献
9.
[reaction: see text] The Sc(OTf)3/FERRODIOL (2) complex was prepared at -78 degrees C in CH2Cl2 in the presence of 2,6-lutidine and MS 4A. The chiral scandium Lewis acid-catalyzed asymmetric Diels-Alder reaction of cyclopentadiene (3) with 3-acyloxazolidin-2-ones (4) effectively produced the adduct (5) in a high yield with good selectivity, i.e., endo/exo = 90:10 up to 91% ee (endo). 相似文献
10.