Ein neues Chrommineral in Serbien

Ohne Zusammenfassung     

Die Nitrate des Chroms und Aluminiums

Ohne Zusammenfassung     

Inégalités différentielles linéaires de Tchapliguine de l'ordre arbitraire dans l'intervalle infini

Résumé On donne, dans le premier chapitre, l'introduction concernant les résultats connus relatifs au r?le de la fonction de Cauchy dans la théorie des inégalités de Tchapliguine de l'ordre arbitraire. Le deuxième chapitre contient la démonstration de la non-negativitè de la fonction de Cauchy dans le cas où toutes les racines de l'équation caractéristique de l'èquation différentielle linéaire aux coefficients constants sont réels et ainsi que dans le cas où l'équation caractéristique a la forme (r−r₁)ⁿ=0. Ce fait permet l'existence de la limite infinie d'application des inégalités de Tchapliguine. Le troisième chapitre a pour l'objet “ les équations de garantie ” concernant des inégalitès différentielles linéaires de l'ordre arbitraire. On construit des classes d'équations à la limite infinie d'application des inégalités de Tchapliguine. On donne, dans le quatrième chapitre, l'asymptotique des solutions de l'équation d'Abel de deuxième espèce illustrant la possibilité de la validitè des inégalités de Tchapliguine du premier ordre pour x →+∞. Entrata in Redazione il 10 settembre 1969.     

Study of Self‐Assembly of the Lignin Model Compound on Cellulose Model Substrate

Herein we report a topographical study of the supramolecular organization of enzymatically polymerized lignin model compound – dehydrogenative polymer (DHP) of coniferyl alcohol – on cellulose substrate, using the Environmental Scanning Electron Microscopic (ESEM) technique. A comparison of deposits obtained by bulk polymerization in solution and direct polymerization in the presence of cellulose substrate shows distinct differences in supramolecular organization. DHP polymerized in solution expresses a 3‐D structure with short‐range ordered motifs, while the polymer formed in the presence of cellulose substrate arranges in a single layer compact structure consisting of several domains. Such structures could be described as a two‐dimensional hexagonal close packed lattice(HCPL), with the dimension of unit cell in 1 μm range. The domains have a quite regular structure with few lattice defects, forming a good example of two‐dimensional colloidal crystal. The growth of DHP globules and their assembly into supramolecular structures are interpreted in terms of cooperative electrostatic interaction of polymer precursors, with a framework of cellulose OH groups and interfacial interactions (hydrophilic/hydrophobic) in the course of the structure growth. The results strongly suggest that the carbohydrate matrix in plant cells can serve as a template for lignin structure formation in the plant cell wall.

Self‐assembled lignin model compound on cellulose substrate.     

Properties of optical excitations in polymers

We consider the influence of the nonconservation effects on the properties of elementary excitations induced by an electromagnetic field in the polymer or chain sytstem. The hamiltonian is derived which conserves the number of elementary excitations (quasi-particles). The harmonic energy spectrum of the elementary excitations arising in the system is determined.     

Solitons in a molecular chain with impurities

The propagation of Davydov's soliton in the molecular chain with an impurity has been investigated. The numerical analysis demonstrates that the presence of the impurity leads to the decreasing of the soliton velocity, as well as to the localization (pinning) of the excitation in a region of space close to the impurity or even to the reflection or destruction of the soliton. The analytical results which demonstrate that the influence of the impurity is equivalent to the existence of some localized external inhomogeneous field or friction force have been obtained also.     

Electrodeposition of Zn-Mn/CeO2 composite coatings: evaluation of corrosion properties

Journal of Solid State Electrochemistry - The aim of this paper is electrodeposition of Zn/CeO2 and Zn-Mn/CeO2 nanocomposite coatings. Four plating solutions were used (R1–R4). Solution R1...     

Effects of dielectric barrier discharge in air on morphological and electrical properties of graphene nanoplatelets and multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) have been functionalized by dielectric barrier discharge (DBD) in air. The extent of functionalization of MWCNTs and GNPs reaches a maximum at the delivered discharge energy of 720 and 240 J mg⁻¹, respectively. Further exposure to plasma leads to reduction of functional groups from the surface of the treated nanomaterials. It has also been demonstrated that DBD plasma does not produce dramatic structural changes in MWCNTs, while flakes of the treated GNPs become thinner and smaller in the lateral size. Conductive thin films, obtained by drop casting a solution of the treated nanomaterials in N-methyl-1-pyrrolidone on poly(methyl methacrylate) substrate, show significantly lower sheet resistance.