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1.
H. Jaskólska L. Rowińska M. Radwan 《Journal of Radioanalytical and Nuclear Chemistry》1974,20(2):419-428
In view of the inhomogeneous distribution of lanthanum in steel, large samples should be used for the determination of this element. The method elaborated consists in the preparation of an average samople by dissolving 50 g steel and analysing an aliquot of the obtained solution corresponding to 0.5 g of steel. In order to reduce the activity of the sample, iron and some other elements are separated from the steel solution by electrolysis prior to irradiation. The amount of lanthanum contamination introduced during the pre-irradiation treatment of the sample is relatively low (10?10–10?9 g) if the treatment is carried out under suitable conditions. The post-irradiation treatment consists in the separation of24Na by shaking the sample solution with Sb2O5. The140La-activity is measured by means of a γ-spectrometer (1.6 MeV photopeak). 相似文献
2.
PrF3 as well as PrF3-LiF and PrF3-MgF2 mixtures were investigated by means of high-energetic excitation with synchrotron radiation. In the PrF3 emission spectrum bands due to the intra-configurational 4f24f2 transitions originating from the 1S0 level of the Pr3+ ion have been identified. The emission from the 3P0 multiplet is very weak due to non-radiative decay by cross-relaxation processes. Therefore, PrF3 is not an efficient direct cascade emitter. In the PrF3 excitation spectra in the ultraviolet/vacuum-ultraviolet spectral range, the 3H41S0 transition at 46858 cm-1 as well as broad bands due to the inter-configurational 4f24f5d transitions are observed. By comparison with data of Pr3+ doped YF3, the branching ratios of the emission transitions for PrF3 from the 1S0 were determined; these are 0.008, 0.075, 0.262, 0.023 and 0.629 for transitions 1S03H4, 3F4, 1G4, 1D2 and 1I6, respectively. For the polycrystalline PrF3-LiF and PrF3-MgF2 samples investigated by us, the measured emission and excitation spectra are nearly identical
to those of PrF3. For polycrystalline PrF3-KMgF3 the observed spectra are superpositions of the PrF3 and Pr3+:KMgF3 spectra. PACS 42.70.-a; 78.55.-m; 78.55.Hx 相似文献
3.
I. Sokólska 《Applied physics. B, Lasers and optics》2000,71(2):157-162
LaGaO3 crystals doped with Er3+ ions were grown by the Czochralski method and their optical properties were examined. The Er3+ energy levels have been determined from the low-temperature absorption and emission spectra. The results of Judd–Ofelt analysis
are presented and compared with experimental data. The emission cross sections are determined for the 4
I
13/2→4
I
15/2 (1.55 μm) and 4
I
11/2→4
I
13/2 (2.85 μm) transitions of erbium.
Received: 6 December 1999 / Revised version: 10 February 2000 / Published online: 27 April 2000 相似文献
4.
I. Sokólska E. Heumann S. Kück T. Lukasiewicz 《Applied physics. B, Lasers and optics》2000,71(6):893-896
Laser oscillation around 1.6 μm was realised at room temperature for low-doped Er:YVO4 crystals (0.5 at % and 1 at %) as well as for Er(1 at %), Yb(5 at %):YVO4 crystal in continuous-wave mode. The maximum slope of the input–output curve was about 19% (vs. absorbed power) for Er(0.5 at %):YVO4. The laser oscillation was discretely tunable in the spectral range between 1531 and 1604 nm.
Received: 24. August 2000 / Published online: 8 November 2000 相似文献
5.
H. Jaskólska L. Rowińska M. Radwan 《Journal of Radioanalytical and Nuclear Chemistry》1971,7(1):29-39
In a search for internal isotopic tracers in metallurgical materials a group of elements has been chosen which can be determined
by the neutron activation method with the higher sensitivity. A method has been developed for the determination of W, As,
Au, La, In, Sc, Re and Ir in metallurgical materials. The separation of the elements was carried out using extraction and
precipitation. The determination of the elements was carried out in samples of chamotte brick and washed ores. The limits
of the determination of the elements are of the order of 10−11 g for Au, 10−10 g for In and La and 10−9 g for As, W, Sc, Re and Ir. The large scatter of the results indicates the inhomogeneity of the materials analyzed. 相似文献
6.
7.
Copper and silver N‐heterocyclic carbene (NHC) complexes were prepared through a simple, base‐free protocol involving the decomposition of corresponding imidazol(in)ium‐2‐carboxylates under thermolytic conditions and a subsequent reaction of the in situ generated carbenes with copper(I) or silver(I) chloride, respectively. The desired NHC metal complexes were isolated with good yields after simple crystallization. 相似文献
8.
Spectroscopic characterization of a Tm3+:SrGdGa3O7 crystal 总被引:2,自引:0,他引:2
W. Ryba-Romanowski S. Gołvab I. Sokólska G. Dominiak-Dzik J. Zawadzka M. Berkowski J. Fink-Finowicki M. Baba 《Applied physics. B, Lasers and optics》1999,68(2):199-205
3 O7 crystal have been recorded at room temperature and at approximately 8 K. Room-temperature luminescence lifetimes of 1D2, 1G4, 3H4, and 3F4 states have been measured for Tm concentration ranging from [%at.]0.5 to [%at.]9. Based upon these data the crystal field
splitting of luminescent states has been derived and radiative transitions rates have been evaluated. Strong self-quenching
of luminescence originating in the 1G4 and 3H4 states has been found in this activator–host combination. Peak emission cross section of the potential laser transition at
1800 nm was determined to be 3.9×10-21 cm2 and the gain coefficient versus wavelength was estimated and discussed.
Received: 14 April 1998/Revised version: 10 August 1998 相似文献
9.
Radioisotopic methods of investigation of Nd behaviour during pulling of single crystals of YAG-type garnets were applied. For the investigation of homogeneity of Nd distribution an autoradiographic method was used, and for the determination of Nd contents in single crystals and Nd effective partition ratios — techniques of radiotracers and gamma spectrometry. The conclusions from this work can find technological application. 相似文献
10.
Refractory bricks labelled with lanthanum or gold were used to determine the origin and quantity of exogenic inclusions in steel. After the melting process the steel samples were activated in the reactor and measured by means of a gamma-ray spectrometer. Steel samples, labelled refrctory bricks as well as both gold and lanthanum solutions were activated to be used as reference samples. Performances and evaluation of the experiments are described. 相似文献