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141.
H. Güven N. Güngör A. Alemdar C. Ş. Özben 《Journal of Radioanalytical and Nuclear Chemistry》1996,214(4):269-276
Instrumental neutron activation analysis was applied to the determination of trace elements in a Na-bentonitic clay. The irradiation was done in the Triga Mark II type reactor of ITU Nuclear Energy Institute. The sample was irradiated in two steps for short- and long- lived isotopes. After irradiation, spectra were taken using a germanium detector, multichannel analyzer Canberra System 100 and a fitting program called Sampo 90. The spectra of short-lived isotopes were analyzed to determine Al, Mg, Na, K, Ca, Ti elements and Mn, V trace elements. The spectra of long-lived isotopes were analyzed to determine Sc, Br, Sb, Cs, La, Ce, Sm, Yb, Hf, Pa, Np trace elements. 相似文献
142.
I. M. Miranda Salvado F. M. A. Margaça J. Teixeira 《Journal of Sol-Gel Science and Technology》1994,2(1-3):289-294
Silica-titania gels, prepared in acidic conditions, with contents of TiO2 up to 6 mol%, have been studied by small angle neutron scattering (SANS) as wet gel with increasing aging times. In all samples, small primary particles have been found with a diameter of about 3 nm. At the gel point, cylindrical clusters, ca. 10 nm long, were observed as well. These grow with aging time, becoming branched. The cluster-cluster diffusion limited aggregation model is found to be consistent with the SANS results. The growth process is independent of the TiO2 content. It is mainly influenced by the ratio of the aging time to the gelation time. 相似文献
143.
B. Karakelle N. Öztürk A. Köse A. Varinlioğbrevelu A. Y. Erkol F. Yilmaz 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(3):649-651
The city of Kocaeli is in the western part of Anatolia in Turkey and has a population of approximately 1.000.000. There is no information about radioactivity in the Kocaeli soils samples so far. For this reason, the concentrations of the natural radionuclides in soil samples from 27 different sampling stations in Kocaeli Basin and its surroundings have been determined. The results have been compared with other radioactivity measurements in different country"s soils. The typical concentrations of 137Cs, 238U, 40K, 226Ra, 232Th found in surface soil samples ranged from 2±0.6 to 25±6 Bq/kg, from 11±4 to 49±10 Bq/kg, from 161±30 to 964±127 Bq/kg, from 10±4 to 58±11 Bq/kg, and from 11±3 to 65±13 Bq/kg, respectively. 相似文献
144.
Ben Salah M Vilminot S André G Richard-Plouet M Bourée-Vigneron F Mhiri T Kurmoo M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(8):2048-2057
[Mn(3)(OH)(2)(SO(4))(2)(H(2)O)(2)] and its deuterated analogue were synthesized by a hydrothermal technique and characterized by differential thermal analysis, thermogravimetric analysis, and IR spectroscopy. Its nuclear structure, determined by single-crystal X-ray analysis and Rietveld analysis of neutron powder-diffraction data, consists of a 3D network of chains of edge-sharing Mn(1)O(6), running along the c axis, connected by the apices of Mn(2)O(6) and SO(4) units. It is isostructural to the nickel analogue. Determination of the magnetic structure and measurements of magnetization and heat capacity indicate the coexistence of both magnetic long-range ordering (LRO) and short-range ordering (SRO) below a Néel temperature of 26 K, while the SRO is retained at higher temperatures. The moments of the two independent Mn atoms lie in the bc plane, and that of Mn(1) rotates continuously by 54 degrees towards the c axis on decreasing the temperature from 25 to 1.4 K. While the SRO may be associated with frustration of the moments within a Mn(3) trimer, the LRO is achieved by antiparallel alignment of the four symmetry-related trimers within the magnetic unit cell. A spin-flop field, measured by dc and ac magnetization on a SQUID, is observed at 15 kOe. 相似文献
145.
Annette Marchand Pierre Gerval Françoise Duboudin M.-H. Gaufryau Marguerite Joanny Pierre Mazerolles 《Journal of organometallic chemistry》1984,267(1):93-106
Intermediates with π-bonded Si or Ge are generated during gas phase pyrolysis of 1,2-disila- or 1,2-digerma-cyclohex-4-enes.Compounds such as R2MMR2 are successfully trapped by addition or [2 + 2] and [4 + 2] cycloadditions. These results were proved by mass spectrometry. 相似文献
146.
Hydrogen-aarbonyl chelation and magnesium-arene π coordination are proposed to aooount for enhanced enantioselectivïty in 1,4-addition reactions of chiral cuprates. 相似文献
147.
Bertrand Pierre Broniatowski Michel Marcotorchino Jean-François 《Advances in Data Analysis and Classification》2022,16(4):1069-1093
Advances in Data Analysis and Classification - This paper aims at comparing two coupling approaches as basic layers for building clustering criteria, suited for modularizing and clustering very... 相似文献
148.
The applicability of a new leaching method, the HSS (H2O2-Na2SO4-H2SO4) system, in the extraction of uranium from Saricaolu-Bergama Region low grade ore, and the efficiency of Acigol Lake (Denizli)-Turkey water as a natural source of Na2SO4 has been investigated. The effect of H2SO4 concentration, temperature, leaching time, H2O2 and Na2SO4 concentrations and the amount of Acigol Lake water on the extraction of uranium was examined. HSS was found suitable for the extraction of uranium from Saricaolu-Bergama Region samples and it was observed that the acid consumption could be decreased by adding Na2SO4. 相似文献
149.
F. M. Lanças M. A. Barbirato N. R. Antoniosi filho 《Journal of Radioanalytical and Nuclear Chemistry》1995,189(2):319-323
Three nitrogenated fungicides (Bayfidan, Bayleton and Baycor) were irradiated with -rays from a60Co source with the products being analyzed by high resolution gas chromatography (HRGC). Within the dose range studied (5 to 640 kGy), all three compounds were found to be stable. 相似文献
150.
Summary The conformation and relative configuration of [1-(2H-azirin-2-yl)alkyl]phosphonates (2) has been established by thorough investigation of some characteristic representatives of the series by1H,13C,15N, and31P NMR spectroscopy. It is shown that the chemical shift of the proton located to the phosphonate group can be used as a criterion for the discrimination and stereochemical assignment of diastereoisomers. NMR spectroscopic features of the compounds are discussed in terms of structural relationships.Dedicated to Univ.-Prof. Dr.K. Schlögl with the best wishes to his 70th birthday 相似文献