A thermal resistive window flow counter available for hard beta-emitters in radio gaschromatography effluents was developed.
The plateau region of the counter showed more than 150 volts long even if the counter was operated at temperature up to 200°C.
The radio gas-chromatograms for real samples containing high boiling compounds showed high resolution and shapper peaks. 相似文献
As a new method, stable-isotope dilution activation analysis has been developed. When an element consists of at least two stable isotopes which are converted easily to the radioactive nuclides through nuclear reactions, the total amount of the element (xg) can be determined by irradiating simultaneously the duplicated sample containing small amounts of either enriched isotope (y g), and by using the following equation. $${{x = y\left( {{M \mathord{\left/ {\vphantom {M {M*}}} \right. \kern-\nulldelimiterspace} {M*}}} \right)\left[ {\left( {{{R*} \mathord{\left/ {\vphantom {{R*} R}} \right. \kern-\nulldelimiterspace} R}} \right)\left( {{{\theta _2^* } \mathord{\left/ {\vphantom {{\theta _2^* } {\theta _2 }}} \right. \kern-\nulldelimiterspace} {\theta _2 }}} \right) - \left( {{{\theta _1^* } \mathord{\left/ {\vphantom {{\theta _1^* } {\theta _1 }}} \right. \kern-\nulldelimiterspace} {\theta _1 }}} \right)} \right]} \mathord{\left/ {\vphantom {{x = y\left( {{M \mathord{\left/ {\vphantom {M {M*}}} \right. \kern-\nulldelimiterspace} {M*}}} \right)\left[ {\left( {{{R*} \mathord{\left/ {\vphantom {{R*} R}} \right. \kern-\nulldelimiterspace} R}} \right)\left( {{{\theta _2^* } \mathord{\left/ {\vphantom {{\theta _2^* } {\theta _2 }}} \right. \kern-\nulldelimiterspace} {\theta _2 }}} \right) - \left( {{{\theta _1^* } \mathord{\left/ {\vphantom {{\theta _1^* } {\theta _1 }}} \right. \kern-\nulldelimiterspace} {\theta _1 }}} \right)} \right]} {\left[ {1 - \left( {{{R*} \mathord{\left/ {\vphantom {{R*} R}} \right. \kern-\nulldelimiterspace} R}} \right)} \right]}}} \right. \kern-\nulldelimiterspace} {\left[ {1 - \left( {{{R*} \mathord{\left/ {\vphantom {{R*} R}} \right. \kern-\nulldelimiterspace} R}} \right)} \right]}}$$ Where M and M* are atomic weights of the element to be determined and the enriched isotope used as a spike,θ1 andθ2 are natural abundances of two stable isotopes in the element,θ1* andθ2* are isotopic compositions of the above isotopes in the enriched isotope, and R and R* are counting ratios of gamma-rays emitted by two radionuclides produced in the sample and the isotopic mixture. Neither calibration standard nor correction of irradiation conditions are necessary for this method. Usefulness of the present method was verified by photon activations of Ca, Zn and Ce using isotopically enriched48ca,68Zn and142Ce. 相似文献
The synthesis of five different polymers containing sugar residues on side chain is described. 1-O-Methacryloyltetra-O-acetyl-D -glucose, 1-O-methacryloyltetra-O-acetyl-D -galactose, and 6-O-methacryloyltetra-O-acetyl-D -glucose were prepared and polymerized. The polymethacrylates obtained were converted into water-soluble polymers by removing the acetyl protective group with sodium methoxide. 6-O-Methacryloyldiisopropylidene-D -galactose was also prepared and polymerized. The isopropylidene protective group was removed by acid hydrolysis. Poly (N-methacryloylglucosamine) was prepared directly by the polymerization of N-methacryloyl-D -glucosamine without the use of any protective group. 相似文献
After the silicon has been anodized, the silica film formed is removed by dilute hydrofluoric acid, and the antimony in the etching solution determined by nondispersive atomic fluorescence spectrometry. The amount of silicon removed is measured in the etching solution by inductively-coupled plasma atomic emission spectrometry. Down to 1018 atoms Sb cm-3 can be determined at sectioning intervals of 50 nm. 相似文献
The anionic polymerization of three monomers, 2-isopropenyl-4,5-dimethyloxazole(I), 2-isopropenylthiazole(II), and 2-isopropenylpyridine(III), was studied in THF. These monomers produced red-colored living polymers on addition of sodium naphthalene or living α-methylstyrene tetramer as an initiator. It was observed that a considerable amount of monomer remained in the respective living polymer–monomer system, indicating that an equilibrium between the polymer and the monomer existed as in the case of α-methylstyrene. At lower temperatures, the conversion of the monomer to the polymer increased. The equilibrium monomer concentrations [Me] were determined at different temperatures, and the heats (ΔH) and the entropies (ΔS°) of polymerization were obtained by plotting In(1/[Me]) against 1/T as ΔH = ?9.4, ?6.8, and ?6.2 kcal/mole, ΔS°S = ?22.9, ?16.5, and ?16.6, eu for I, II, and III, respectively. 相似文献
The behaviour of hydrogen in metals has been investigated by a channelling method utilizing a nuclear reaction1H(11B, ). The results are briefly summarized. 相似文献
L X-ray spectra of iodine and antimony compounds were measured using a doublecrystal spectrometer, L4 X-rays emitted from the valence 5p electrons were found to be sensitive to the chemical environment. The L4/L3, L1/L1 and L2,15/L1 intensity ratios were remarkably changed in various compounds of these elements. L4 energies of iodine compounds were shifted with the increase of the formal oxidation number. 相似文献