Variety of LaSrMnO structures induced by growth conditions and laser irradiation

Crystallographic phase transitions in perovskite-like LaSrMnO metallic oxides are studied. The transitions are induced when internal stresses generated during film synthesis (at temperatures between 450 and 730°C) vary (decrease or increase) upon subsequent irradiation by a KrF laser emitting in the UV range. As the synthesis temperature T _s grows, the rhombohedral-to-orthorhombic phase transition occurs at 650–670°C. The resistivity is shown to be either temperature-independent, ρ(T)=const, at T<T _crit, or varies and reaches a maximum, ρ(T)=ρ_max, at the Curie temperature T _c. Optical transmission spectra taken at photon energies ℏω=0.5–2.5 eV exhibit both a high (0.8–0.9) and low (0.1–0.3) transmission coefficient t, depending on the synthesis temperature. As follows from X-ray diffraction data, the laser irradiation causes a phase transition only in LaSrMnO films grown at T _s<650°C. Phases of different size scales appear: the long-range-order orthorhombic matrix and mesoscopic-range-order rhombohedral clusters are observed in the films grown at T _s=450–550°C and the rhombohedral matrix with orthorhombic clusters, in the films grown at T _s=550–650°C.     

A marker method for the solution of the damped Burgers' equation

A new method for the solution of the damped Burgers' equation is described. The marker method relies on the definition of a convective field associated with the underlying partial differential equation; the information about the approximate solution is associated with the response of an ensemble of markers to this convective field. Some key aspects of the method, such as the selection of the shape function and the initial loading, are discussed in some details. The marker method is applicable to a general class of nonlinear dispersive partial differential equations. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006     

The study of titration conditions in the aluminium and beryllium-fluoride systems

Summary The Study of Titration Conditions in the Aluminium and Beryllium-Fluoride Systems The conditions for the titrimetric determination of aluminium and beryllium using fluoride as a titrant and a fluoride indicator electrode have been determined. 10g ml^–1 Al and 3g ml^–1 Be have been determined with precision better than 0.4%. The formation of slightly soluble sodium hexafluoroaluminate or tetrafluoroberyllate is primarily responsible for the end point breaks. The study of the reaction conditions (ethanol, sodium and acetate ions concentration) made the calculation of stepwise stability constants for aluminium- or beryllium-fluoride complexes, aluminium- or beryllium-acetate complexes as well as that of the solubility products of the corresponding sodium salts possible.     

The influence of selected metals and halogens on the electronic system of benzoic acid

The influence of halogens and metals on the electronic system of the aromatic ring in lithium, sodium and potassium complexes with p-halogenobenzoic acids has been investigated by means of ¹³C and ¹H NMR, IR and Raman spectroscopy and semi-empirical calculations. It has been shown that ionic potentials and electronegativities of halogens and metals are the main factors responsible for perturbations of the electronic charge distribution in the ring.     

八乙墓卟啉和四苯基卟啉合钌（Ⅱ）及锇（Ⅱ）的二氧加合物的红外光谱

ＯＥＰ（八乙基卟啉阴离子）和ＴＰＰ（四苯基卟啉阴离子）合钌（Ⅱ）和锇（Ⅱ）的二氧加合物由ｍａｔｒｉｘ分离技术得到（Ｔ＝２０－４３Ｋ，Ｐ＝１０－５－１０－６ｔｏｒｒ）．为了确定ｖ（Ｏ２）带的归属应用了同位素取代法１６Ｏ２／１８Ｏ２．ＩＲ谱说明对于钌的两种加合物（指ＯＥＰ和ＴＰＰ）都有两种异构体，其Ｖ（１６Ｏ２）频率为：Ｒｕ（ＯＥＰ）Ｏ２，１１４１和１１０３ｃｍ－１；Ｒｕ（ＴＰＰ）Ｏ２，１１６７和１１１４ｃｍ－１．Ｏｓ（ＴＰＰ）Ｏ２只生成一种异构体，ｖ（１６Ｏ２）＝１０９０ｃｍ－１，异构体ｖ（１６Ｏ２）：［Ｒｕ（ＯＥＰ）Ｏ２］，１１４１ｃｍ－１，［Ｒｕ（ＴＰＰ）Ｏ２］，１１６７ｃｍ－１，这些加合物约在１００Ｋ时分解，它们的结构指定为ｅｎｄｏｎ，而异构体［Ｒｕ（ＯＥＰ）Ｏ２］，１１０３ｃｍ－１，［Ｒｕ（ＴＰＰ）Ｏ２］，１１１４ｃｍ－１和［Ｏｓ（ＴＰＰ）Ｏ２］，１０９０ｃｍ－１，在２４０—２７０Ｋ分解，它们的结构指定为桥联二聚体．在加合物中，将ＯＥＰ换成ＴＰＰ引起的钌加合物ｖ（Ｏ２）频率的改变比铁和钴加合物更大．ｖ（Ｏ２）相对强度的变化顺序为：Ｆｅ（Ⅱ）→Ｒｕ（Ⅱ）→Ｏｓ（Ⅱ）．     

Electrochemical Behavior of Cobaltocene in Ionic Liquids

The electrochemical behavior of cobaltocenium has been studied in a number of room temperature aprotic ionic liquids. Well defined, diffusion controlled, anodic and cathodic peaks were found for the Cc⁺/Cc (cobaltocenium/cobaltocene) reduction/oxidation on gold, platinum and glassy carbon electrodes. Values of the peak separation parameters suggest quasireversibility or even irreversibility for the redox process. The difference between the ferrocene/ferrocenium and cobaltocenium/cobaltocene couples has been evaluated as equal to (1.350 ± 0.020) V. Values of the cobaltocenium (Cc⁺) diffusion coefficients D have been calculated on the basis of the Randles–Sevcik equation.     

Sustainable Drying and Torrefaction Processes of Miscanthus for Use as a Pelletized Solid Biofuel and Biocarbon-Carrier for Fertilizers

Miscanthus is resistant to dry, frosty winters in Poland and most European Union countries. Miscanthus gives higher yields compared to native species. Farmers can produce Miscanthus pellets after drying it for their own heating purposes. From the third year, the most efficient plant development begins, resulting in a yield of 25–30 tons of dry matter from an area of 1 hectare. Laboratory scale tests were carried out on the processes of drying, compacting, and torrefaction of this biomass type. The analysis of the drying process was conducted at three temperature levels of the drying agent (60, 100, and 140 °C). Compaction on a hydraulic press was carried out in the pressure range characteristic of a pressure agglomeration (130.8–457.8 MPa) at different moisture contents of the raw material (0.5% and 10%). The main interest in this part was to assess the influence of drying temperature, moisture content, and compaction pressure on the specific densities (DE) and the mechanical durability of the pellets (DU). In the next step, laboratory analyses of the torrefaction process were carried out, initially using the Thermogravimetric Analysis TGA and Differential Scaning Calorimeter DSC techniques (to assess activation energy (EA)), followed by a flow reactor operating at five temperature levels (225, 250, 275, 300, and 525 °C). A SEM analysis of Miscanthus after torrefaction processes at three different temperatures was performed. Both the parameters of biochar (proximate and ultimate analysis) and the quality of the torgas (volatile organic content (VOC)) were analyzed. The results show that both drying temperature and moisture level will affect the quality of the pellets. Analysis of the torrefaction process shows clearly that the optimum process temperature would be around 300–340 °C from a mass loss ratio and economical perspective.