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861.
Photoinduced electron transfer (PET) fluoroionophores (1b, 2b) that consist of diazacrown and two 9-anthryl pendants show fluorescent enhancement with various guest salts. The diaza-12-crown-4 derivative (2b) exhibited Zn(2+) selectivity and in the presence of this cation the host fluorescence intensity was increased by a factor of 182. The guest cation-induced fluorescence enhancement of 2b was larger than the diaza-18-crown-6 derivative (1b). 相似文献
862.
The present state of a long term program is reviewed. It was started to elaborate a remote controlled automated radiochemical
processing system for the neutron activation analysis of biological materials. The system is based on wet ashing of the sample,
followed by reactive desorption of some volatile components. The distillation residue is passed through a series of columns
filled with selective ion screening materials to remove the matrix activity. The solution is thus “stripped” from the interfering
radioions, and it is processed to single-elements through group separations using ion-exchange chromatographic techniques.
Some special problems concerning this system are treated. (a) General aspects of the construction of a (semi)automated radiochemical
processing system are discussed; (b) Comparison is made between various technical realizations of the same basic concept;
(c) Some problems concerning the “reconstruction” of an already published processing system are outlined. 相似文献
863.
Conclusions A convenient method of preparing organochlorohydridesilanes by selective chlorination of organohydridesilanes with stannic chloride was proposed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2114–2117, September, 1967. 相似文献
864.
Evolution of Statistical Ensembles of Microdomains on the Surface of Films of Rigid-Chain Polyimide during Thermal Imidization 总被引:1,自引:0,他引:1
Bronnikov S. V. Sukhanova T. E. Goikhman M. Ya. 《Russian Journal of Applied Chemistry》2003,76(6):967-971
Statistical ensembles of microdomains formed on the surface of polyimide films based on pyromellitic dianhydride and 2,7-diaminofluorene during thermal imidization were described in terms of the model of reversible aggregation using the electron-microscopic data. Parameters of the statistical distribution were determined for each ensemble depending on the film heating temperature. 相似文献
865.
Toyoda M Ishihara M Yamaguchi S Ito H Matsuo T Roll R Rosenbauer H 《Journal of mass spectrometry : JMS》2000,35(2):163-167
A new type of multi-turn time-of-flight mass spectrometer was constructed, consisting of four cylindrical electric sectors and 28 electric quadrupole lenses, the size of the vacuum chamber being 60 x 70 x 20 cm. It was demonstrated that the mass resolution can be increased according to the number of cycles of the ions through the ion optical system. 相似文献
866.
N. K. Gusarova B. A. Trofimov T. N. Rakhmatulina S. F. Malysheva S. N. Arbuzova S. I. Shaikhudinova A. I. Albanov 《Russian Chemical Bulletin》1994,43(9):1591-1592
The reaction of styrene and -methylstyrene with P in aprotic polar solvents in the presence of KOH affords diorganylphosphinous acids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1680–1681, September, 1994. 相似文献
867.
Ion-selective electrode with cellulose triacetate membrane containing nonactin is employed for the potentiometric detection of ammonia produced in biocatalytic reaction in flow-injection system with enzyme reactor. The elimination of interferences occurring in the presence of alkali metal ions was achieved by covering a nonactin membrane with outer hydrophobic gas permeable membrane. The obtained flow-injection response to ammonia indicates a possibility of ammonia determination down to 10 microM ammonia. In the flow-injection system for urea determination 200 microl of 10-fold diluted blood serum sample was injected into carrier stream of distilled water merged with TRIS buffer, passed through the urease flow-through reactor and then after merging with NaOH stream delivered to the detector. It was found in several series of natural blood serum samples, that the correction for endogenous ammonia in such a determination is not indispensable. 相似文献
868.
T. A. Danilova R. G. Aukharieva S. N. Petrov S. Ya. Grobovenko E. A. Viktorova 《Chemistry of Heterocyclic Compounds》1981,17(9):883-886
The thio-Claisen rearrangement of isomeric 3- and 1-methylallyl phenyl sulfides was investigated. It is demonstrated that the thio-Claisen rearrangement of the 3-methyl isomer is preceded by its thioallyl rearrangement to the 1-methyl isomer. The latter undergoes thio-Claisen rearrangement to o-(3-methylallyl)thiophenol, which is cyclized to 2-ethyl-2,3-dihydrobenzothiophene and 2-methylthiochroman under the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1191–1194, September, 1981. 相似文献
869.
Sakuratani Y Yamada J Kasai K Noguchi Y Nishihara T 《SAR and QSAR in environmental research》2005,16(5):403-431
External validation of the biodegradability prediction model CATABOL was conducted using test data of 338 existing chemicals and 1123 new chemicals under the Japanese Chemical Substances Control Law. CATABOL predicts that 1089 chemicals will have a BOD < 60% while 925 (85%) actually have an observed BOD<60%. The percentage of chemicals with an observed BOD value <60% tends to increase as the predicted BOD values decrease. In contrast, 340 chemicals were predicted to have a BOD > or = 60% and 234 (69%) actually had an observed BOD > or = 60%. The prediction of poor biodegradability was more accurate than the predictions of high biodegradability. The features of chemical structures affecting CATABOL predictability were also investigated. 相似文献
870.
Thirty three compounds were obtained from the bulbs of Urginea maritima (Liliaceae). The compounds were identified by means of fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic resonance (1H-NMR), (13C-NMR), nuclear overhauser effects (NOE) and two dimensional (2D) NMR. Ten of them were new natural compounds. Nine were bufadienolides and only one was lignan in these compounds. 相似文献