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1.
A rapid separation method has been developed which allows measurement of plutonium, americium and strontium isotopes in the high active sample from CBRN Training and Testing Centre in Zemianske Kostolany (Slovakia) with high chemical recoveries and effective removal of matrix interferences. This method uses different commercial products stacked AnaLig® Pu-02, AnaLig® Sr-01 and DGA® Resin cartridges from IBC Advanced Technologies and Eichrom Technologies. The method allows rapid separation of plutonium, strontium and americium using a single multi-stage column in the vacuum box (cartridge technology) with rapid flow rates to minimize sample separation time. The 239,240Pu, 238Pu and 241Am were determined by alpha spectroscopy, 90Sr was counted on TRICARB 2900 TR by Cerenkov counting of its progeny 90Y.  相似文献   

2.
The238Pu,239,240Pu and137Cs concentrations in sediments and shore deposition samples of the Vltava river were determined.239,240Pu and137Cs concentrations in sediment samples (five locations) ranged from 19.6 to 124.8 mBq·kg−1 and from 1.8 to 28.2 Bq·kg−1, respectively. The238Pu,239,240Pu and137Cs concentrations in shore deposition samples (four locations) ranged from 2 to 16.8, from 26.8 to 477.2 mBq·kg−1, and from 1.6 to 86.3 Bq·kg−1, respectively. The superficial activity of studied radionuclides in shore deposition areas was determined and radionuclide origin at studied locations was discussed.  相似文献   

3.
A rapid separation method has been developed which allows measurement of plutonium, americium and strontium isotopes in the radioactive sludge from Nuclear power plant A1 Jaslovske Bohunice (NPP A1) with high chemical recoveries and effective removal of matrix interferences. This method uses different commercial products stacked AnaLig? Pu02, AnaLig? Sr01 and TRU? Resin cartridges from IBC Advanced Technologies and Eichrom Technologies. The method allows the rapid separation of plutonium, strontium and americium using a single multi-stage column in the vacuum box (cartridge technology) with rapid flow rates to minimize sample separation time. The 239,240Pu, 238Pu and 241Am were determined by alpha spectroscopy, 90Sr was counted on TRICARB 2900 TR by Cerenkov counting of its progeny 90Y.  相似文献   

4.
《Tetrahedron: Asymmetry》2000,11(10):2117-2123
Reduction of ethyl 2-chloro-3-phenyl-3-oxopropionate with borohydride affords predominately the syn-chlorohydrin. Resolution of this ester with the lipase MAP-10 gives (2S,3R)-2-chloro-3-hydroxypropionic acid which after esterification with MeOH/HCl is converted to the cis-epoxide with potassium carbonate and DMF. Aminolysis of the epoxide with aqueous ammonia results in ring opening and amide formation. The amide is converted to an ester upon treatment with isobutyl alcohol and HCl(g) at 100°C. Neutralization then affords the Taxol® side chain as the free amine.  相似文献   

5.
The main aim of the TrainMiC® Convention was to gather TrainMiC® authorized trainers from all 19 countries involved in this programme. About 90% of all authorized TrainMiC® trainers assembled at this Convention, which shows the interest in and usefulness of the TrainMiC® system. The role and position of the authorized trainers was formally recognized by the introduction of a User License Agreement (based on a European Commission Decision, concerning the granting of a copyright license for TrainMiC® trainers, 17 December 2008) which was signed by the attendants. Participants received an update on the training material and could give their input and suggestions for improvement, which will then be discussed and reviewed by the Editorial Board. It is this which makes TrainMiC® a truly devolved and living system which can adapt itself. Participants also gave their input on how to further develop TrainMiC® from a system point of view. Topics included better focus on priority sectors, improved course interactivity, further improvement of pedagogical skills of authorized trainers, better marketing and identifying multiple sources of funding.  相似文献   

6.
This work reports on the survey carried out to determine the presence of microcystins (MCs) by using ELISA tests and HPLC-UV for such determination in different sample sites along the Spanish course of the Guadiana River. The most important cyanobacteria species identified were, Microcystis aeruginosa and Oscillatoria spp. The highest total microcystin content recorded was 6.40?µg?L?1 in 2002. The main toxins found were microcystins RR and LR, with microcystin YR present at trace levels. Improvements in sample clean up were carried out by using Immunoaffinity solid phase extraction (SPE) and its advantages regarding to conventional SPE were clearly demonstrated. The confirmation of MCs presence in the evaluated water reservoirs, underlines the necessity of monitoring programs as well as the improvement of analytical methodologies to efficiently prevent the human health risks as a consequence of MCs contamination.  相似文献   

7.
137Cs, 241Am and Pu isotopes were analyzed in seawater, bottom sediments (BS) and suspended particulate matter samples collected in the Baltic Sea during 1997–2011. The particle size distribution and sequential extraction studies were carried out with the aim to better understand the association of radionuclides with particles and their bonding patterns in the BS. δ13Corg was applied for identification of sources of organic matter in the studied area. It has been found that massic activities of 137Cs in BS varied from 2.1 to 588 Bq/kg. High correlation of 137Cs massic activities with total organic carbon (TOC) in BS (r = 0.75) and with clay minerals (r = 0.95) was found. 239,240Pu massic activities in BS varied from 0.03 to 7.5 Bq/kg. High correlation with TOC was found for 239,240Pu (R = 0.98) as well as for 241Am (r = 0.96). δ13Corg in the studied samples ranged from ?22.3 to ?31.8 ‰.  相似文献   

8.
The aim of this study is to investigate the radiation-modifying effects of incorporating commercially available bismuth-, tin- and zinc-based compounds in the composition of the PRESAGE® dosimeter, and the feasibility of employing such compounds for radiation dose enhancement. Furthermore, we demonstrate that metal compounds can be included in the formulation to yield water-equivalent PRESAGE® dosimeters with enhanced dose response. Various concentrations of the metal compounds were added to a newly developed PRESAGE® formulation and the resulting dosimeters were irradiated with 100 kV and 6 MV photon beams. A comparison between sensitivity and radiological properties of the PRESAGE® dosimeters with and without the addition of metal compounds was carried out. Optical density changes of the dosimeters before and after irradiation were measured using a spectrophotometer. In general, when metal compounds were incorporated in the composition of the PRESAGE® dosimeter, the sensitivity of the dosimeters to radiation dose increased depending on the type and concentration of the metal compound, with the bismuth compound showing the highest dose enhancement factor. In addition, these metal compounds were also shown to improve the retention of the post-response absorption value of the PRESAGE® dosimeter over a period of 2 weeks. Thus, incorporating 1–3 mM (ca. 0.2 wt%) of any of the three investigated metal compounds in the composition of the PRESAGE® dosimeter is found to be an efficient way to enhance the sensitivity of the dosimeter to radiation dose and stabilize its post-response for longer times. Furthermore, the addition of small amounts of the metal compounds also accelerates the polymerization of the PRESAGE® dosimeter precursors, significantly reducing the fabrication time. Finally, a novel water-equivalent PRESAGE® dosimeter formula optimized with metal compounds is proposed for clinical use in both kilovoltage and megavoltage radiotherapy dosimetry.  相似文献   

9.
Procedure for analysis of plutonium isotopes in soil samples was developed using a new molecular recognition technology product AnaLig?Pu-02 gel. Extraction chromatography TEVA? Resin was used for purification of plutonium phase to remove thorium impurities which interfere in Pu determination by alpha spectrometry. The performance of the method was successfully tested by analysis of a sand stimulant sample and a soil sample spiked with known activity of 239Pu. The results obtained for procedures were compared in terms of activities and recoveries.  相似文献   

10.
11.
The influence of the forming conditions on the structure and properties of Aquivion® perfluorinated proton-conducting membranes prepared by casting from a dimethylformamide solution was studied. At properly chosen and controlled conditions of solvent evaporation and subsequent heat treatment, membranes with more ordered morphology and structure, high level of mechanical properties, and high proton conductivity can be obtained. These results are attributed to the structural self-organization of the polymer base of the membranes in the course of nanofilm formation. The properties of Aquivion® type membranes prepared by casting and pressing were compared. The possibility of improving the strength properties of the membranes to the level close to that of the membranes prepared by extrusion was demonstrated.  相似文献   

12.
The purpose of this study was to evaluate the effect of three swallowing aids on the adsorbent properties and palatability of a mixture of the oral charcoal adsorbent, Kremezin?. None of the swallowing aids had any effect on the adsorption of indole by Kremezin?, either in vitro and in vivo. In gustatory sensation tests of the palatability of the swallowing aids with Kremezin?, 14 items were evaluated according to the semantic differential (SD) method. Factor analysis of the results identified two main factors 'Remaining after removing from mouth' and 'Sense of holding in mouth' as predominantly determining the palatability. The swallowing aid with the highest viscosity allowed the best dispersion of Kremezin?, and also improved the palatability of Kremezin? the most.  相似文献   

13.
The molecular–topological structure of a terpolymer based on vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene has been studied for the first time with the use of thermomechanical spectrometry. A five-block topologically amorphous and crystalline pseudo-network structure with crystallites, which have different initial melting temperatures, as branching points has been detected in the terpolymer at temperatures from–100 to 250°C. When γ-irradiated at a dose of 30 kGy, the crystalline blocks of high-temperature modifications assimilated into one cluster block with the formation of a pseudo-network with a 1.5fold increase in the block-average molecular weight and a decreased initial molecular flow temperature.  相似文献   

14.
诸平  原因 《化学教育》1997,18(9):42
94号元素杯是美国核化学家,1951诺贝尔化学奖得主之一西博格(G. T. Seaborg)等人于1940年发现的。  相似文献   

15.
 The hydride and phenyl groups on the silica surface were determined qualitatively and quantitatively. The calculation of the molar decadic absorptivities of the Si*H-stretching vibration band at 2293 cm−1 and of the C*H-stretching vibration band at 3068 cm−1 was carried out according to Lambert-Beer’s law.  相似文献   

16.
Pu(Ⅲ)、Pu(Ⅳ)、Pu(Ⅴ)和Pu(Ⅵ)在自然水的pH和Eh(氧化还原电势)值范围内能够共存。 在自然环境中主要以Pu(Ⅴ)的PuO2(H2O)+n和Pu(Ⅳ)的Pu(OH)4形式存在。 采用静态法测定了Pu(Ⅳ)和Pu(Ⅴ)在砂土介质中的分配系数Kd,Pu(Ⅳ)和Pu(Ⅴ)在砂土中的分配系数范围分别为5.5×103~4×104 mL/g 和3.2×103~1.1×104 mL/g。 表明在砂土介质中Pu(Ⅳ)的分配系数(Kd)大于Pu(Ⅴ)的,并且分配系数随砂土介质中粘土矿物含量的增加及介质颗粒粒径减小而增大。  相似文献   

17.
Regular one-dimensional (1D) parallel chains composed of CdS nanoparticles with cubic zinc blende crystal structure were prepared at the air/water interface via one-step synthesis and assembly process. These nanostructures were produced through an interfacial reaction between Cd(2+) ions in the aqueous solution of cadmium acetate and H(2)S in the gaseous phase under Langmuir monolayers of 10,12-pentacosadiynoic acid (PDA). It was demonstrated that PDA molecules self-assembled into parallelly aligned linear supermolecules at the air/water interface with the aid of π-π interactions and acted as templates for the formation of the superstructures. The experimental conditions including temperature and reaction time have great influences on the superstructure formation and the parameters of the parallel chains.  相似文献   

18.
19.
《Tetrahedron: Asymmetry》1998,9(21):3819-3823
Sclareolide was efficiently resolved by a diastereomeric salt formation method using homochiral erythro-2-amino-1,2-diphenylethanol (ADPE) as a resolving agent.  相似文献   

20.
Surfaces are often characterized with phrases like “easy to clean”, “dirt repellent”, “dirt resistant”, “self cleaning” or “ Lotus -Effect®”. Every one of those phrases is used to describe a behavior of surfaces - similar to each other but still different. This article is providing the definition of the Lotus -Effect®, techniques to manufacture self cleaning surfaces and methods to characterize them as well. How to generate a self cleaning surface depends on the substrate and the use later on. It can be as easy as a spray on but on the other hand as complicated as a three step process. Self cleaning surfaces are defined by four parameters - contact angle, roll-off angle, hystereses and C.I.E-Lab Δ-L value.  相似文献   

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