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Abstract  

With pulse decay discrimination function and using diisopropylnaphthalene based scintilation cocktail, liquid scintillation analysis (LSA) becomes a rapid and reliable method for monitoring emitting nuclides in environmental samples. Recent developments of instrumentation and cocktail of LSA are described. Procedures and results of monitoring gross activity in vegetable samples and plutonium in soil samples are given. The Minimum Detectable Activity was 4.5×10–2 Bq/Kg for vegetable samples and was 6.6×10–5 Bq/g for soil samples.

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Abstract  

Simple, rapid and sensitive methods are very important for the bioassay of plutonium. In this work, modern liquid scintillation technique combined with selective extraction separation and / pulse decay discrimination were studied and evaluated for the bioassay of plutonium. After sample decomposition and partial evaporation, cyclohexanone and trialkylphosphine oxide (TRPO) were used for the separation of plutonium from matrix. Several different cocktails were tested for liquid scintillation analysis of urine samples. The minimum detectable activity (MDA) of this method was estimated to be 0.01 Bq/500ml urine with 100 minutes measuring time and 3 confident level.

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Alanine- and taurine-salicylal Schiff base complexes of magnesium

Synthesis, characterization and thermal decomposition

Journal of Thermal Analysis and Calorimetry
Authors: S. Luan, Y. Zhu, and Y. Jia

Abstract  

The complexes of α-alanine-salicylal Schiff base of magnesium (α-ASSM), β-alanine-salicylal Schiff base of magnesium (β-ASSM) and taurine-salicylal Schiff base of magnesium (TSSM) were synthesized. The formulae of the complexes are Mg[OC6H4CHNCH(CH3)COO]·2H2O, Mg[OC6H4CHNCH2CH2COO]·2H2O and Mg[OC6H4CHNCH2CH2SO3]·2H2O. The crystal structure belongs to orthorhombic system with the lattice parameters: a=1.6954 nm, b=2.0873 nm and c=2.3037 nm for the β-ASSM, to orthorhombic system with the lattice parameters: a=1.5586 nm, b=1.8510 nm and c=2.6240 nm for the β-ASSM, to monoclinic system with the lattice parameters: a=1.3232 nm, b=1.4960 nm, c=2.1543 nm and β=98.04° for the TSSM, respectively. The results of the thermal decomposition processes and infrared spectra of the complexes show that the complexes may possess different coordination structures.

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Abstract  

A novel method that spent nuclear fuel is converted into nitrates with N2O4, and then nitrates are extracted with TBP in supercritical CO2 (SC-CO2), has been developed for reprocessing of spent nuclear fuel, which has a potential prospect because of its potential to decrease generation of the secondary liquid waste. In this paper, conversion of Nd2O3 with N2O4 into its nitrate under various conditions and extraction of the conversion product with TBP in SC-CO2 were investigated. When temperature was 60–120 °C, the molar ratio of H2O to Nd2O3 was from 1 to 6, and molar ratio of N2O4 to Nd2O3 was above 8, complete conversion of Nd2O3 into its nitrate was achieved. The conversion product was characterized by thermal analysis (TG-DTA), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR) and Raman spectroscopy. Quantitative extraction of the conversion product with TBP in supercritical CO2 was also achieved under experimental conditions.

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Abstract  

An Al2(WO4)3 target bombarded with a proton beam (28.5 MeV, 20 A) for 1 hour was completely dissolved in about 5 ml of hot 2N NaOH and the clear solution was neutralized with 2N HCl. The resulted white precipitate of Al2(WO4)3 can be separated from the solution by centrifugation and decantation. The supematant containing radioactive Re as ReO 4 was loaded onto a column (1 cm×10 cm) of activated alumina (100–200 mesh). Eluted with 10 ml of saline, the carrier-free ReO 4 was collected, while the small amount of Al2(WO4)3 in the supematant was adsorbed on the column. The total yield of ReO 4 was 94.7% and the breakthrough of WO 4 2– , only 1.0·10–6 M. The whole separation process can be accomplished within 30 minutes. This rapid and efficient Re/W separation protocol is applicable to the preparation of carrier-free186Re, when an enrichel Al2(186WO4)3 target is used.

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Abstract  

It is proposed to use 14 MeV neutrons tagged by the associated particle neutron time-of-flight technique (APnTOF) to identify the fillers of unexploded ordnances (UXO) by characterizing their carbon, nitrogen and oxygen contents. To facilitate the design and construction of a prototype system, a preliminary simulation model was developed, using the Geant4 toolkit. This work established the toolkit environment for (a) generating tagged neutrons, (b) their transport and interactions within a sample to induce emission and detection of characteristic gamma-rays, and (c) 2D and 3D-image reconstruction of the interrogated object using the neutron and gamma-ray time-of-flight information. Using the modeling, this article demonstrates the novelty of the tagged-neutron approach for extracting useful signals with high signal-to-background discrimination of an object-of-interest from that of its environment. Simulations indicated that an UXO filled with the RDX explosive, hexogen (C3H6O6N6), can be identified to a depth of 20 cm when buried in soil.

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Summary

Yanghuo Sanqi tablet (YST), combined prescription mainly derived from the leaves of Herba epimedii and the roots of Panax notoginseng, is a traditional Chinese medicine (TCM). Flavonoids (icarrin, epimedin A, epimedin B, epimedin C, and baohuoside I) and saponins (notoginsenoside R1, ginsenoside Rgl, and ginsenoside Rbl) are considered as the main bioactive compounds of YST. However, there is no report on quality control of TCMs by simultaneous determination of above-mentioned flavonoids and saponins so far. In this work, for the first time, a high-performance liquid chromatography-diode array detector-evaporative light scattering detector (HPLC-DAD-ELSD) method was developed to evaluate the quality of YST through a simultaneous determination of five major active flavonoids and three main saponins. Optimum separations were obtained with a Zorbax SB-C18 column by gradient elution with acetonitrile-water as the mobile phase. The drift tube temperature of ELSD was set at 105 °C, and the nebulizing gas flow rate was 2.5 L min−1. The fully validated method was successfully applied to quantify the eight bioactive components in three lot products. This simple, low-cost, and reliable HPLC-DAD-ELSD method provided a new basis for assessing the quality of traditional Chinese medicinal compound preparations (TCMCPs) consisting of many bioactive components.

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Summary

Yanghuo Sanqi tablet (YST), combined prescription mainly derived from the leaves of herba epimedii and the roots of Panax notoginseng, is a traditional Chinese medicine (TCM). Flavonoids (icarrin, epimedin A, epimedin B, epimedin C, and baohuoside I) and saponins (notoginsenoside R1, ginsenoside Rgl, and ginsenoside Rbl) are considered as the main bioactive compounds of YST. However, there is no report on quality control of TCMs by simultaneous determination of above-mentioned flavonoids and saponins so far. In this work, for the first time, a high-performance liquid chromatography-diode array detector-evaporative light-scattering detector (HPLC-DAD-ELSD) method was developed to evaluate the quality of YST through a simultaneous determination of five major active flavonoids and three main saponins. Optimum separations were obtained with a Zorbax SB-C18 column by gradient elution with acetonitrile-water as the mobile phase. The drift tube temperature of ELSD was set at 105 °C, and the nebulizing gas flow rate was 2.5 L min−1. The fully validated method was successfully applied to quantify the eight bioactive components in three lot products. This simple, low-cost, and reliable HPLC-DAD-ELSD method provided a new basis for assessing the quality of traditional Chinese medicinal compound preparations (TCMCPs) consisting of many bioactive components.

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Abstract  

The microcalorimetric method and DNA site-directed mutagenesis technique were used together to study the effect of transcription start site mutagenesis on RM07 promoter activity and gene transcription efficiency in Escherichia coli. The results revealed that once the putative transcription start site G was mutated to T, the promoter activity of RM07 promoter fragment was decreased and the transcription strength of cat reporter gene was weakened. Our work suggests that the nucleotide component of transcription start site is very critical for the promoter strength and the gene transcription efficiency. Our research also provides a new and useful technique for determining the transcription start site using both chemical and biological method.

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Novel magnetic solid-phase extraction using carboxylated multiwalled carbon nanotubes was proposed with ultra high-performance liquid chromatography–tandem mass spectrometry for the determination of silodosin in biological samples. The effects of various experimental parameters including adsorbent amount, pH, adsorption time, desorption conditions, and adsorbent reusability were systematically validated. Under the optimized conditions, the calibration curve was linear within the concentration range of 1.0–800 ng mL−1 with the correlation coefficient of 0.9997 and the lower limit of detection was 0.3 ng mL−1. The extraction recoveries were over 90.0% with relative standard deviation (RSD) of less than 5.0%. All these results suggested that magnetic extraction method can be used for enrichment and quantification of silodosin in biological samples.

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