共查询到20条相似文献,搜索用时 15 毫秒
1.
Masamitsu Shirai Masahiro Tsunooka Makoto Tanaka Kanji Nishijima Katsukiyo Ishikawa 《Journal of polymer science. Part A, Polymer chemistry》1989,27(1):325-332
Novel photosensitive polymers were synthesized by the copolymerization of methyl methacrylate and 1,2,3,4-tetrahydro-1-naphthylideneimino p-styrenesulfonate (NISS) and by the ternary polymerization of methyl methacrylate, methacrylic acid, and 9-fluorenylideneiminop-styrene-sulfonate (FISS). NISS and FISS units showed good sensitivity to light of wavelengths below 300 nm and below 366 nm, respectively. Although the polymers were insoluble in aqueous alkaline solutions, on irradiation with UV light they became soluble in aqueous alkaline solutions. A remarkable decrease in molecular weight of the polymers was observed during the photolysis of imino sulfonate groups incorporated into the polymers, which assisted the dissolution of the irradiated polymers. 相似文献
2.
M. Yamamoto 《Journal of Radioanalytical and Nuclear Chemistry》1985,90(2):401-408
A method was developed for the rapid dissolution of plutonium in soil by fusion with ammonium hydrogen sulfate, and the determination of plutonium content by ion exchange separation and alpha spectrometry. By this method, plutonium in environmental soil containing plutonium oxide in a soluble and/or insoluble form could successfully be determined. 相似文献
3.
MJ Romero R Pedrido AM González-Noya M Maneiro MI Fernández-García G Zaragoza MR Bermejo 《Dalton transactions (Cambridge, England : 2003)》2012,41(35):10832-10844
The coordinative chemistry of the tridentate half-salen ligand 5-(dimethylamino)-N-(2-((2-hydroxybenzylidene)amino)phenyl)naphthalene-1-sulfonamide (H(2)L, 1) has been studied by means of an electrochemical method. All of the complexes have been characterised using analytical and spectroscopic techniques. Ligand 1 and two nickel (6 and 7), copper (9), zinc (12) and cadmium (14) metal complexes have been studied by crystallography. Complexes 6 and 7 are octahedral and tetrahedral nickel(ii) complexes, respectively, and both contain an [L](2-) molecule that behaves in an [N(2)O] tridentate manner. Nickel(ii) completes its coordination kernel with three water molecules in complex 6, whereas in complex 7 the nickel ion is further bound to a molecule of dansylamine arising from a hydrolysis process. The copper(ii) complex 9 is a monomeric compound that contains a bideprotonated ligand thread and a dimethylsulfoxide molecule coordinated through the sulfur atom. The zinc complex 12 is an unusual pentanuclear cluster compound whose structure consists of four anionic ligand units and two hydroxo anions bound to five zinc(ii) centres. The appearance of the hydroxo anions in this complex provides new evidence for water reduction electrochemically promoted by zinc metal under mild conditions. The cadmium complex 14 is a dimeric compound that comprises two molecules of the anionic ligand and two dimethylsulfoxide molecules. The great structural variety exhibited by all these complexes demonstrates that the introduction of asymmetry in a salen skeleton by incorporating a dansyl pendant increases the versatility of the resulting ligand on coordination. All complexes are luminescent in solution at room temperature in acetonitrile solutions. 相似文献
4.
N. D. Bryan F. R. Livens A. D. Horrill 《Journal of Radioanalytical and Nuclear Chemistry》1994,182(2):359-366
Field observations suggest that plutonium and americium in the environment are present in very different chemical forms in the interstitial waters of an intertidal sediment. Themodynamic modelling using the PHREEQE code predicts that plutonium is present entirely in oxidation state (V) as the PuO2CO
3
–
ion, whereas americium is present entirely in oxidation state (III), largely as the uncharged Am(OH)CO3 species, but with significant concentrations of the Am3+ and the AmSO
4
+
ions. There are, however, differences between these predictions and others published for a very similar system which apparently arise from uncertainties in the thermodynamic data. Field data cannot resolve these differences unambiguously. 相似文献
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Varga Z 《Analytical and bioanalytical chemistry》2007,389(3):725-732
The origin and release date of environmental plutonium have been assessed by the measurement of plutonium and americium isotopic
composition. The applicability and sensitivity of different plutonium isotope ratios, 240Pu/239Pu and 241Pu/239Pu measured by inductively coupled plasma sector field mass spectrometry and 238Pu/239Pu analysed by alpha spectrometry, have been evaluated for origin determination in several types of environmental samples.
With use of mixing models the contribution of different sources (e.g. global fallout or Chernobyl) can be calculated. By the
measurement of the 241Am/241Pu isotope ratio, the release date (i.e. formation of 241Pu by irradiation) can be estimated in environmental samples, which is an important parameter to distinguish recent plutonium
release from previous (e.g. Chernobyl) emissions. 相似文献
7.
Pyrene-appended calix[4]arenes 6-8 bearing an increasing number (from 2 to 4) of ‘pyrene amide’ residues have been prepared. Their fluorescence behaviour has been investigated to show dependence on the number of pyrene groups. Their behaviour as fluorophores is also described. 相似文献
8.
P. M. Mapara A. G. Godbole Rajendra Swarup M. S. Nagar 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(2):631-635
Solvent extraction and extraction chromatography studies of uranium and plutonium from oxalate supernatant solutions were
carried out using 2-ethyl hexyl-2-ethyl hexyl phosphonic acid (PC88A). Based on the distribution data, it was inferred that
both the uranium and plutonium could be recovered satisfactorily from such a solution. These studies were found to be useful
in optimising the appropriate concentration of PC88A, HNO3, oxalic acid and temperature to recover more than 90% of plutonium from the large volumes of oxalate bearing waste solutions.
Spectral characteristics of the extractant and its complexing behavior with U(VI) was also studied using IR & FTIR. 相似文献
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12.
《Spectrochimica Acta Part B: Atomic Spectroscopy》2005,60(7-8):920-925
The atomic emission of laser-induced plasma on steel samples has been studied for quantitative elemental analysis. The plasma has been created with 8 ns wide pulses using the second-harmonic from a Q-switched Nd:YAG laser, in air at atmospheric pressure. The plasma emission is detected with temporal resolution, using an Echelle spectrometer of wide spectral range (300–900 nm) combined with an intensified charge coupled device camera. A plasma temperature of 7800 ± 400 K is determined using the Boltzmann plot method, from spectra obtained under optimized experimental conditions.As an example of an industrial application the concentration of copper in scrap metals is studied, which is an important factor to determine the quality of the samples to recycle. Cu concentrations down to 200 ppm can be detected. Another application of the laser-induced plasma spectroscopy method is the measurement of the nickel and copper concentrations in an iron-containing sample of reduced magma from the 1870s expedition to western Greenland by Adolf Erik Nordenskiöld. Different spectral lines of nickel are used for calibration, and their results are compared. 相似文献
13.
The methods available for plutonium determination in bioassay and environmental analysis are reviewed with special emphasis on urine and soil samples The individual steps in techniques based on precipitation, solvent extraction, glass-fibre adsorption and ion exchange are discussed. The problems connected with α-counting are also considered briefly. 相似文献
14.
K. L. Ramakumar S. Jeyakumar R. M. Rao L. Gnanayyan H. C. Jain 《Journal of Radioanalytical and Nuclear Chemistry》1995,190(1):121-136
Simultaneous isotopic analysis of uranium and plutonium using thermal ionization mass spectrometer coupled to a multi-collector detection assembly with 9 Faraday cups has been reported earlier. Subsequently investigations have been carried out (1) to understand the applicability of correction methodologies available to account for the contribution of238Pu at238U and (2) to evaluate the effectiveness of these methodologies on the accuracy of235U/238U atom ratio being determined, particularly when samples containing different U/Pu atom ratios. Isotopic fractionation for both U and Pu in the simultaneous isotopic analysis has been compared with the results of the individual analysis of these elements. The different isotopic fractionation factors observed for U were attributed to different conditions of analysis. There was no significant difference in the isotopic fractionation patterns for Pu. The consideration to extend this method to actual samples from our observations on synthetic samples with diferent U/Pu atom ratios containing U and Pu isotopic reference standards is described. 相似文献
15.
A study involving the scope of substrate in the Knoevenagel reaction in an IL medium has been conducted. Reactivity trends favor formation of the condensation product using electron deficient aryl aldehydes. Use of electron rich aldehydes and ketones lead to lower levels of conversion and no measurable amounts of condensation products, respectively. A recycling study confirmed that the reaction medium could be used multiple times affording, with each run, the desired condensation product 1a in excess of 90% conversion. Post-run analyses of the IL documented that the IL medium was unaltered upon reuse. 相似文献
16.
Müzeyyen Demirel Gülsel Yurtdaş Lütfi Genç 《Journal of inclusion phenomena and macrocyclic chemistry》2011,70(3-4):437-445
Ketoconazole (KZ) is an imidazole antifungal agent which is administered topically and also orally. KZ is practically insoluble in water. Vaginal candidiasis is a common condition and up to 75% of all women have at least one episode of this infection during their lifetime. The aim of study was to prepare KZ/β-cyclodextrin (β-CD) complex to improve the physicochemical properties of KZ and to investigate the possibility of preparing vaginal suppositories with the complexes. A linear increase in KZ solubility as a function of β-CD concentration was verified using the phase-solubility diagram. The resulting diagram was classified as AL-type, is generally related to the formation of a soluble complex. Complexes were prepared in a 1:1 molar ratio by different methods, namely freeze-drying, spray-drying, co-evaporation and kneading. Characterization of the complexes prepared was performed by practical yield %, aqueous solubility, active agent amount analyses, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffractometry (PXRD) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Characterization studies provided additional evidences of complexation. The paddle method defined in USP31 was used in in vitro dissolution experiments on the prepared vaginal suppositories. It was found that solubility enhancement by preparing KZ/β-CD complexes depends on the type of the preparation method. Dissolution of KZ from complexes was found to be faster than the active agent and the commercial suppositories. This result may be attributed to the interactions between β-CD and active agent, high energetic amorphous state and decrease in the interfacial tension between insoluble active agent and dissolution media. 相似文献
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It is shown that the absorptiometric determination of molybdenum as thiocyanate may be used in the presence of plutonium. Molybdenum interferes with previously published methods for determining uranium and plutonium but conditions have been established for its complete removal by solvent extraction of the compound with a-benzoin oxime. The previous methods for uranium and plutonium are satisfactory when applied to the residual aqueous phase following this solvent extraction. 相似文献
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N. N. Mirashi P. M. Shah S. K. Aggarwal 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(3):479-482
Determination of americium is one of the requirements of chemical quality assurance of plutonium bearing fuel materials. Alpha-spectrometry
is generally used for the determination of 241Am in Pu bearing fuels since the efficiency of semiconductor detector used for alpha-spectrometry is independent of the alpha-particle
energy in the 4 to 8 MeV range. However, this method has limitations for Pu samples containing extremely small or very large
amounts of 241Am. Thus an alternative methodology based on alpha/gamma (α/γ) activity ratio was developed and tested using different samples.
The method is based on the determination of total γ-activity (of 60 keV peak) of an aliquot of the solution and the total
α-activity present in the aliquot. The method is fast as it does not involve chemical separation of Pu and Am as required
in the alpha-spectrometric method. Data obtained on synthetic and real life samples demonstrates the usefulness of the developed
alpha/gamma ratio method for the determination of 241Am in Pu bearing fuel samples. 相似文献