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81.
82.
A method for the determination of 36Cl in biological shield concrete of nuclear reactors was developed. Cl in the concrete sample was extracted quantitatively by pyrohydrolysis at 900 degrees C and recovered in Na2CO3 solution for subsequent measurement of 36Cl by liquid scintillation counting. WO3 was used as an accelerator in the pyrohydrolysis. The Cl extraction procedure was optimized by investigating experimental conditions with the use of ion chromatography and its recovery was evaluated by the analysis of the geochemical reference samples. The detection limit of 36Cl was 0.02 Bq g(-1) for a sample weight of 2 g. The relative standard deviation was 3-7% for the samples containing 0.5 Bq g(-1) levels of 36Cl. The method was applied to determine 36Cl in biological shield concrete of the Japan Power Demonstration Reactor. 相似文献
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Sakai R Koike T Sasaki M Shimamoto K Oiwa C Yano A Suzuki K Tachibana K Kamiya H 《Organic letters》2001,3(10):1479-1482
[structure: see text] A new excitatory amino acid, neodysiherbaine A (2), was isolated as a minor constituent of the aqueous extract from the marine sponge Dysidea herbacea. The structure was deduced by spectroscopic methods and established unambiguously by the total synthesis. The present synthesis, including as a key step cross-coupling of the 6/5-bicyclic core with an amino acid residue, is useful in constructing its structural analogues. 相似文献
85.
Flow-through chemiluminescence sensor using immobilized oxidases for the selective determination of L-glutamate in a flow-injection system. 总被引:1,自引:0,他引:1
A selective and sensitive chemiluminometric flow sensor for the determination of L-glutamate in serum, based on immobilized oxidases such as glutamate oxidase (GOD), uricase (UC) and peroxidase (POD), is described herein. The principle for the selective chemiluminometric detection for L-glutamate is based on coupled reactions of four sequentially aligned immobilized oxidases, UC/POD/GOD/POD in a flow cell. The immobilized UC was employed to decompose urate, which is one of the major interfering components in serum for a luminol-H2O2 chemiluminescence reaction. The H2O2 produced from the UC reaction readily reacted with reducing components, such as ascorbate and glutathione, and then the excess H2O2 was decomposed by the immobilized POD. L-Glutamate in the sample plug was enzymatically converted to H2O2 with immobilized GOD. Subsequently, the peroxide reacts with luminol on the immobilized POD to produce chemiluminescence, proportional to glutamate concentration. The enzymes were immobilized on tresylated poly(vinyl alcohol beads). The immobilized enzymes were packed into TPFE tube (1.0 mm i.d. x 60 cm), in turn, and used as a flow cell. The sampling rate was 30 h-1. The calibration graph for L-glutamate is linear for 20 nM-5 microM; the detection limit (signal-to-noise = 3) is 10 nM. 相似文献
86.
The thermodynamic properties of the spinel ferromagnetic compounds CdCr2Se4 and CdCr2S4 have been investigated by making heat capacity and thermal expansion measurements on single crystals. For both compounds, the ferromagnetic transition is marked by λ-type thermal anomalies, and the results provide a pressure dependence of the transition temperatures that is in agreement with direct measurements. Below the transition, CdCr2S4 shows an anomalous heat-capacity contribution and negative thermal expansion, which are in contrast to the conventional behavior found in CdCr2Se4. 相似文献
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A method of estimating the β-strength function from β-decay data on three neighbouring nuclei is proposed. This method is most effective for the β? decay ofodd-Z even-N nuclei with the neutron number equal to a magic number plus two, and is applied to the β? decays of 87Br and 137I The strength functions estimated by this method represent the general trend of experimental data fairly well except for the regions of the lowest and highest excitation energies, where this method is either inapplicable or subject to large uncertainties. The delayed neutron emission probabilities are estimated for these precursors by use of these strength functions, and the results are in agreement with experiment within a factor of two. 相似文献