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61.
62.
Takeshi Saito Toshihide Ihara Tooru Miura Yuuko Yamada Koichi Chiba 《Accreditation and quality assurance》2011,16(8-9):421-428
The accurate quantification of pesticide residues in food is an important factor in assuring the quality of life of our citizens. In general, chromatographic methods are used, which require certified reference materials (CRMs) for each analyte of interest for accurate quantitative analysis. Recently, regulation of pesticides in food, limiting the positive maximum residue (positive list system) has been brought into effect in Japan. Furthermore, ISO/IEC 17025 requires calibration and testing laboratories to program calibrations and measurements traceable to the International System of Units (SI). Accordingly, these laboratories need a suite of CRMs that are traceable to the SI. In order to address these requirements for every analyte of interest in an efficient manner, a new approach to producing SI traceable CRMs is required. Nuclear magnetic resonance (NMR) has been used widely in chemical analysis. One of the well known characteristics of NMR is the proportional relationship between peak area and the number of nuclei contributing to the peak. If accurate relative intensities of peak areas are obtained, this provides an attractive quantitative tool for organic compounds. The area of a signal from an analyte can be measured with respect to another signal originating from a comparator that has been added to the sample solution. The chosen comparator should not react with the analyte or resonate at any chemical shift similar to that of the analyte. This enables us to produce SI traceable CRMs more effectively. In this paper, we demonstrate a new approach for producing CRMs for pesticides using quantitative NMR??an SI traceable quantitative technique. 相似文献
63.
The coadsorption of 15N2 and O2 on polycrystalline rhenium filament has been studied by thermal desorption mass spectroscopy. The sample was exposed to a mixture of 15N2 and O2 with various concentrations of 15N2 at room temperature. It is suggested that NO on Re at low coverage is dissociative and the bonding strength of nitrogen on Re is weakened by the coadsorption with oxygen atoms. 相似文献
64.
65.
This paper gives an O(n√nlog3n) time algorithm for the chance-constrained sequencing problem on a single machine, where n is the number of jobs and the objective is to minimize the number of jobs which are early with probability not smaller than α (a given constant) against the common due time d. 相似文献
66.
Toshihide Ibaraki 《Discrete Applied Mathematics》1980,2(2):155-158
It is known that a minimization problem having a finite feasible region with k elements can be formulated as an integer programming problem by introducing at most [log2k] additional integer variables. In this note, we show that this bound is best possible in the sense that some minimization problem actually requires [log2k] additional variables. 相似文献
67.
Minji Jin Yu Nagaoka Kazuomi Nishi Kinuyo Ogawa Shoji Nagahata Toshihide Horikawa Masahiro Katoh Tahei Tomida Jun’ichi Hayashi 《Adsorption》2008,14(2-3):257-263
Photocatalysts of TiO2 and La-doped TiO2 were prepared by calcining the pure TiO2 sols and the sols mixed with La(NO3)3⋅6H2O at 873 K, respectively. These photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy
(XPS), scanning electron microscopy (SEM) and N2 adsorption-desorption isotherms measurement. As results, the BET surface area, pore diameter, mesopore volume and micropore
volume slightly increased, while the crystallite size and the phase structure were little affected by lanthanum doping. The
equilibrium adsorption of methylene blue (MB) on the photocatalysts were measured in a dark room. The adsorption isotherms
were confirmed to fit to the Langmuir theory. Photocatalytic activities of the photocatalysts were studied by employing the
photocatalytic degradation of MB in water and degradation of acetaldehyde in air under UV-irradiation using a black light.
Kinetic analysis revealed that the rate controlling steps could be the surface reaction of the adsorbed MB on the catalyst
surface for MB degradation and the reaction of adsorbed acetaldehyde with the gaseous acetaldehyde for degradation of acetaldehyde,
respectively. 相似文献
68.
CO2是最重要的可再生碳源之一.为了将CO2转化为有用的有机化合物,我们研究了二种模型硅基"废"材料—乙硅烷和硅粉的反应活性.在这些反应中,氟盐的催化活性最高,在常压、在质子源水和硅基还原剂的存在下,CO2可转化为甲酸.原位NMR和动力学分析表明,含氢硅烷和五配位的硅物种分别是反应中间物和活性物种. 相似文献
69.
We describe a method of constructing a new kind of splines with compact support on . These basis functions consisting of a linear combination of the cardinal B-splines of mixed orders enable us to achieve
simultaneously a good sampling approximation and an interpolation of any smooth function. 相似文献
70.
Guanidine-containing molecular transporters: sorbitol-based transporters show high intracellular selectivity toward mitochondria 总被引:1,自引:0,他引:1