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21.
The results of and findings from an interlaboratory comparison among laboratories carrying out food testing of pesticide residues
in the APEC (Asia–Pacific Economic Cooperation) region are presented and discussed to show critical roles of chemical metrology
infrastructure in establishing traceability of measurements and in supporting existing measurement capability in safety and
quality of food trade. The study material, which was prepared and certified by Korea Research Institute of Standards and Science
(KRISS), was freeze-dried Chinese cabbage powder fortified with two organophosphorous pesticides (diazinon and chlorpyrifos).
Among 14 participants, 12 laboratories were accredited based on ISO/IEC17025 and one laboratory was under assessment for the
accreditation at the time of this study. Though all participants demonstrated very good intra-day repeatability and inter-day
intermediate precision, many of them showed a large bias from the certified values. It is suggested that in addition to the
accreditation system, economies are encouraged to develop appropriate chemical metrology infrastructure, which could effectively
support laboratories to assure measurement traceability to SI, for which NMIs could play significant roles through their metrological
services recognized in Mutual Recognition Arrangement (MRA) of the International Committee for Weights and Measures (Comité
International des Poids et Mesures, CIPM). 相似文献
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T. ShonoM. Mitani 《Tetrahedron》1972,28(18):4747-4750
Cyclic ketones were electrolytically reduced in isopropanol and in H2SO4H2OMeOH. It was found that, in isopropanol the stereoisomer ratios of the products were approximately equal to the thermodynamic relative stabilities, whereas in H2SO4H2OMeOH the thermodynamically unstable epimeric alcohols formed were more than that anticipated from the relative stabilities. The mechanism of this electroreduction involving the stereoselective adsorption and electron transfer is discussed. 相似文献
24.
Previous psychophysical studies have shown that the perceptual distinction between voiceless fricatives and affricates in consonant-vowel syllables depends primarily on frication duration, whereas amplitude rise slope was suggested as the cue in automatic classification experiments. The effects of both cues on the manner of articulation between /integral of/ and /t integral of/ were investigated. Subjects performed a forced-choice task (/integral of/ or /t integral of) in response to edited waveforms of Japanese fricatives /integral of i/, /integral of u/, and /integral of a/. We found that frication duration, onset slope, and the interaction between duration and onset slope influenced the perceptual distinction. That is, the percent of /integral of/ responses increased with an increase in frication duration (experiments 1-3). The percent of /integral of/ responses also increased with a decrease in slope steepness (experiment 3), and the relative importance between slope portions was not even but weighted at onset (experiments 1 and 2). There was an interaction between the two cues of frication duration and steepness. The relative importance of the slope cue was maximum at a frication duration of 150 ms (experiment 3). It is concluded that the frication duration and amplitude rise slope at frication onset are acoustic cues that discriminate between /integral of/ and /t integral of/, and that the two cues interact with each other. 相似文献
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The first examples of furan substituted with an SF5 group are reported. 3-pentafluorosulfanylfurans were prepared from their respective 2-pentafluorosulfanyl-5-cyano-7-oxabicyclo[2.2.1]hept-2-ene precursors via retro-Diels-Alder reactions. Also, a tandem cycloaddition/retrocycloaddition reaction between 4-phenyloxazole and 1-pentafluorosulfanylhex-1-yne was used to prepare 3-pentafluorosulfanyl-4-butylfuran. [reaction: see text]. 相似文献
28.
Taishi Taken Obu Hideo Shimoda Yoshihiro Iwasa Tadaoki Mitani Mayumi Kosaka Kats Umi Tanigaki 《Molecular Crystals and Liquid Crystals》2013,570(1):599-604
Abstract Correlations among lattice parameter, external pressure, and critical temperature Tc has been surveyed on fullerene superconductors with a wide range of lattice parameters and various valence states. The observed value of dTc/dP for Na2Rb0.5Cs0.5C60 and Li3CsC60, having small interfullerene separations, is about a few times lager than that of K3C60. In contrast, small dTc/dP values are found in fullerides with expanded unit cells, such as (NH3)xNaAA?C60 (A, A? = K, Rb and Cs) and A3Ba3C60. Interestingly, the chemical and physical pressure effects on Tc are considerably different in these fullerides with large interfullerene spacings. Our results suggest that the pressure dependence is scaled by an interfullerene distance when the interfullerene distances is small, but that this scaling fails when the unit cell is expanded. 相似文献
29.
Y. Iwasa X. H. Chen T. Takenobu T. Mitani 《Molecular Crystals and Liquid Crystals》2013,570(1):583-586
Abstract Raman spectra have been measured on BaxC60 binary systems for x=3, 4 and 6. The pentagonal pinch Ag(2) mode exhibits a softening in an approximately proportional manner to the formal valence of C60 molecule. This result suggests that the valence of C60 in Ba doped systems are understood by the naive ionic crystal model based on Ba2+. The broader Raman peaks in superconducting Ba4C60 indicates that the electron-phonon interaction is considerably large comparing to those for Ba3C60 and Ba6C60. 相似文献
30.
Palladium‐Catalyzed Domino CH/NH Functionalization: An Efficient Approach to Nitrogen‐Bridged Heteroacenes
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Natsuyo Kamimoto Dr. Dieter Schollmeyer Dr. Koichi Mitsudo Prof.Dr. Seiji Suga Prof.Dr. Siegfried R. Waldvogel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8257-8261
Palladium‐catalyzed domino C?H/N?H functionalization for the synthesis of novel nitrogen‐bridged thienoacenes and 10H‐benzo[4,5]thieno[3,2‐b]indole derivatives from dihaloarene is reported. This domino sequence consists of initial C?H functionalization of the benzo[b]thiophene moiety, followed by Buchwald–Hartwig coupling. This transformation is also useful for the synthesis of highly π‐extended compounds. 相似文献