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991.
The possibility of using synthesized iron(III) and cobalt(II) molybdophosphates as dyes in dyeing of copolymers and polymeric formulations based on methacrylic acid and methyl methacrylate and also as pigments deposited onto natural and inorganic supports for heterogeneous dyeing of polymeric materials was studied.  相似文献   
992.
A gas chromatograph for the rapid determination of explosives (2,4-dinitrotoluene, 2,4,6-trinitrotoluene, and pentaerythritol tetranitrate) and narcotics (heroin, cocaine hydrochloride, and crack) is described, and its analytical characteristics are presented. The instrument was equipped with a multicapillary column and an ion-mobility spectrometer as a detector.  相似文献   
993.
Regularities in n-hexane conversion on decationized Y zeolites under cracking and aromatization conditions have been studied. Possible formation of lower olefins and benzenes in parallel reactions following different mechanisms at low conversion degrees is suggested. The effect of thermosteam treatment on the activity and selectivity of Y zeolites in n-hexane conversion has been examined.
- Y . , . Y -.
  相似文献   
994.
A method that utilizes the Vilsmeier reaction to form a pyrrole ring was developed for the preparation of the previously unknown 7-formyl-2-methyl-4-oxo-3,4-dihydropyrrolo[3,2-d]pyrimidine from 2,6-dimethyl-5-amino-4-oxo-3,4-dihydropyrimidine. The nitrile, which was converted to the amide, was obtained from the oxime of the synthesized aldehyde. 7-Unsubstituted pyrrolopyrimidine was synthesized by oxidation of the aldehyde to the corresponding acid and subsequent decarboxylation. The IR and PMR spectroscopic data are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1672–1674, December, 1977.  相似文献   
995.
996.
A calculation method of self-shielding coefficients of interesting elements in samples of any forms is given for the neutron activation analysis of cadmium and its compounds. The determination of ten elements in cadmium telluride using radiochemical separation and γ spectrometry is described.   相似文献   
997.
998.
999.
Mesostructured chalcogenide-based materials with long-range order and semiconducting properties can be prepared using suitable molecular building blocks, linkage metal ions and surfactant molecules. In this paper we present surfactant templated, open framework platinum tin selenide and telluride materials assembled using K4SnQ4 (Q = Se, Te) salts and K2PtCl4 as precursors and a study of pore and wall organization. We find that materials prepared in water exhibit disordered pore organization, whereas those prepared in formamide are long-range ordered with hexagonal symmetry. In formamide the [SnQ4]4- anions undergo condensation-oligomerization reactions that produce different chalcogenido molecular species, whereas in water the anions remain intact. In addition to solvent, the pore organization and overall quality of the mesostructured materials strongly depend on the surfactant molecules, i.e., chain length and headgroup size. For example, highly ordered mesostructured platinum tin selenides with hexagonal symmetry were obtained using the hydroxyl-functionalized surfactants CnH2n+1N(CH3)(CH2CH2OH)2Br (n = 16, 18, and 20), but when the headgroup was triethylammonium, hexagonal pore order was achieved only for n = 20 and not for n = 16 and 18. The experimental results imply that in order to achieve highly ordered chalcogenide frameworks a single building anionic block might be insufficient. Finally, we also report the first examples of hexagonal mesostructured Pt/Sn/Te materials based on K4SnTe4 as the precursor. The tellurides behave differently for their selenium analogues and have very low energy band gaps, in the range 0.5-0.7 eV.  相似文献   
1000.
Immobilized Eriochrome Cyanine R was used for the direct determination of trace aluminum and beryllium by diffuse reflectance spectrometry. Anion exchanger AV-17, silica gel Silochrom C-120, Chromaton N-Super, octadecyl silica gel, and cellulose were examined as supports. Optimal sorption conditions were found. The dependence of chromaticity functions (chromaticity coordinates, lightness, color saturation, yellowness, and whiteness) on different factors was studied. Advantages of the use of chromaticity functions rather then the diffuse reflectance coefficient were demonstrated. A method is developed for the separate determination of aluminum and beryllium using cellulose as the support; the method was used for the analysis of real samples and tested with standard samples. When solution samples of 50 and 100 mL were used, the determination limit was 0.004 g/mL for aluminum and 0.0002 g/mL for beryllium.  相似文献   
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