Sonaatti II

Soitinnus: viulu, piano.

Sinfonia II

Digitoitu 9. 5. 2008.

Sinfonia II

Soitinnus: lauluäänet (sopraano, altto), sekakuoro, orkesteri.

Käyrätorvikonsertto II

Soitinnus: käyrätorvi, orkesteri.

Eufonie II

Soitinnus: orkesteri.

Sinfonia II

Soitinnus: orkesteri.

Sinfonia II

Digitoitu 19. 5. 2008.

Psalmus I ja II

Digitoitu 26. 5. 2008.

Magnetic and transport properties of II-V diluted magnetic semiconductors doped with manganese and nickel

This thesis is devoted to investigations of three typical representatives of the II-V diluted magnetic semiconductors, Zn1-xMnxAs2, (Zn1-xMnx)3As2 and p-CdSb:Ni. When this work started the family of the II-V semiconductors was presented by only the compounds belonging to the subgroup II3-V2, as (Zn1-xMnx)3As2, whereas the rest of the materials mentioned above were not investigated at all. Pronounced low-field magnetic irreversibility, accompanied with a ferromagnetic transition, are observed in Zn1-xMnxAs2 and (Zn1-xMnx)3As2 near 300 K. These features give evidence for presence of MnAs nanosize magnetic clusters, responsible for frustrated ground magnetic state. In addition, (Zn1-xMnx)3As2 demonstrates large paramagnetic response due to considerable amount of single Mn ions and small antiferromagnetic clusters. Similar paramagnetic system existing in Zn1-xMnxAs2 is much weaker. Distinct low-field magnetic irreversibility, accompanied with a rapid saturation of the magnetization with increasing magnetic field, is observed near the room temperature in p- CdSb:Ni, as well. Such behavior is connected to the frustrated magnetic state, determined by Ni-rich magnetic Ni1-xSbx nanoclusters. Their large non-sphericity and preferable orientations are responsible for strong anisotropy of the coercivity and saturation magnetization of p- CdSb:Ni. Parameters of the Ni1-xSbx nanoclusters are estimated. Low-temperature resistivity of p-CdSb:Ni is governed by a hopping mechanism of charge transfer. The variable-range hopping conductivity, observed in zero magnetic field, demonstrates a tendency of transformation into the nearest-neighbor hopping conductivity in non-zero magnetic filed. The Hall effect in p-CdSb:Ni exhibits presence of a positive normal and a negative anomalous contributions to the Hall resistivity. The normal Hall coefficient is governed mainly by holes activated into the valence band, whereas the anomalous Hall effect, attributable to the Ni1-xSbx nanoclusters with ferromagnetically ordered internal spins, exhibits a low-temperature power-law resistivity scaling.

Determination of Ni(II) in metal alloys by spectrophotometry UV-Vis using dopasemiquinone

A spectrophotometric method was proposed for Ni(II) determination in alloys using a dopa-semiquinone (L-1) to form [Ni(II)(L1-)3]1-, ε = 9.3 x 10³ L mol-1 cm-1. The optimal conditions for the determination were: wavelength 590 nm, temperature 25 °C, reaction time 45 min and pH 7.5. The Beer's law was obeyed for nickel from 3.33 x 10-5 to 1.78 x 10-4 mol L-1. The method was applied to complex samples, such as inox, nickel-titanium and cobalt-chromium alloys. A study of the potential interferents revealed that Mn was the major interferent. The limit of detection and quantification were 2.88 x 10-5 mol L-1 and 3.06 x 10-5 mol L-1, respectively.

Ternary surface complex: coadsorption of Cu(II), Zn(II), Cd(II) and nitrilotris(methylenephosphonic) acid onto boehmite

This work studies the effect of NTMP (nitrilotris(methylenephosphonic acid)) on the adsorption of Cu(II), Zn(II), and Cd(II) onto boehmite in the pH range 5-9.5. The data were analyzed using the 2-pK constant capacitance model (CCM) assuming ternary surface complex formation. Under stoichiometric conditions, NTMP is more effective for removing Cu(II) than Zn(II) from solution and the contribution of ternary surface complexes are important to model the adsorption of both metals. Under nonstoichiometric conditions and high surface loading with a Me(II)/NTMP ratio of 1:5, Cu(II) and Zn(II) adsorption is significantly suppressed. In the case of Cd(II) the free metal adsorption is the most dominant species.

Theoretical investigation of electronic excitation transfer between chlorophylls in light-harvesting antenna of photosystem ii using quantum computers

The excitation energy transfer between chlorophylls in major and minor antenna complexes of photosystem II (PSII) was investigated using quantum Fourier transforms. These transforms have an important role in the efficiency of quantum algorithms of quantum computers. The equation 2n=N was used to make the connection between excitation energy transfers using quantum Fourier transform, where n is the number of qubits required for simulation of transfers and N is the number of chlorophylls in the antenna complexes.

Syntheses, characterization and antifungal activity of tris(1,10-phenanthroline)iron(ii) bis(n-r-sulfonyldithiocarbimate)zincate(ii)

Four new compounds with the general formula [Fe(phen)3][Zn(RSO2N=CS2)2], where phen = 1,10-phenanthroline, R = 4-FC6H4 (1), 4-ClC6H4 (2), 4-BrC6H4 (3) and 4-IC6H4 (4), respectively, were obtained by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate (RSO2N=CS2K2) and tris(1,10-phenanthroline)iron(II) sulfate, with zinc(II) acetate dihydrate in dimethylformamide. The elemental analyses and the IR data were consistent with the formation of the expected complexes salts. The ¹H and 13C NMR spectra showed the signals for the cationic iron(II) complex and dithiocarbimate moieties. The molar conductance data were consistent with the 1:1 cation:anion complexes in 1-4. The antifungal activities of the compounds were tested in vitro against Candida albicans, Candida tropicalis and Colletotrichum gloeosporioides.

Spectrophotometric study of iron oxidation in the iron(II)/thiocyanate/acetone system and some analytical applications

The possibility of using thiocyanate to determine iron(II) and/or iron(III) in water-acetone mixture has been re-examined as part of a systematic and comparative study involving metallic complexes of pseudohalide ligands. Some parameters that affect the complete oxidation of the ferrous cations, their subsequent complexation and the system stability have been studied to optimize the experimental conditions. Our results show the viability and potentiality of this simply methodology as an alternative analytical procedure to determine iron cations with high sensitivity, precision and accuracy. Studies on the calibration, stability, precision, and effect of various different ions have been carried out by using absorbance values measured at 480 nm. The analytical curve for the total iron determination obeys Beer's law (r = 0.9993), showing a higher sensitivity (molar absorptivity of 2.10x10(4) L cm-1 mol-1) when compared with other traditional systems (ligands) or even with the "similar" azide ion [1.53x10(4) L cm-1 mol-1, for iron-III/azide complexes, in 70% (v/v) tetrahydrofuran/water, at 396 nm]. Under such optimized experimental conditions, it is possible to determine iron in the concentration range from 0.5 to 2 ppm (15-65% T for older equipments, quartz cells of 1.00 cm). Analytical applications have been tested for some different materials (iron ores), also including pharmaceutical products for anemia, and results were compared with atomic absorption determinations. Very good agreement was obtained with these two different techniques, showing the potential of the present experimental conditions for the total iron spectrophotometric determinations (errors < 5%). The possibility of iron speciation was made evident by using another specific and auxiliary method for iron(II) or (III).

Magnetic, thermal and spectral characterization of 2,6-dimethoxybenzoates of Co(II), Ni(II) and Cu(II)

The complexes of 2,6-dimethoxybenzoic acid anion with ions of Co(II), Ni(II), and Cu(II) have been synthesized as polycrystalline solids, and characterized by elemental analysis, spectroscopy, magnetic studies, and also by X-ray diffraction and thermogravimetric measurements. The analysed complexes have following colours: pink for Co(II), green for Ni(II), and blue for Cu(II) compounds. The carboxylate group binds as monodentate, and bidentate bridging and chelating ligands. On heating in air to 1173 K the complexes decompose in four, three or two steps. At first, they dehydrate in one or two steps to anhydrous salts, that next decompose to oxides of the respective metals. The solubility of the investigated dimethoxybenzoates in water at 293 K is of the order of 10-2 mol/dm3. Their magnetic moments were determined in the temperature range of 76-303 K. The results reveal the compounds of Co(II) and Ni(II) to be high-spin complexes and that of Cu(II) to form dimer.