Wyniki wyszukiwania - BazTech

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NuTria - system of modelling of NURBS and triangulated surfaces

Putz B., Przybylski M., Kaźmierski S., Matyskieła P., Zagroba K.

Problemy Eksploatacji

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2007

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nr 3

175-184

EN

The paper presents the idea of a 3D modeller dedicated to bent metal plates modelling, designed as a part of a greater application and destined for small and medium-sized enterprises. The aim of the application is to deliver a simple tool for free form surface modelling in two independent modes: as a rectangular parametric NURBS surface defined by regular net of points or alternatively as a surface smoothly interpolating an irregular set of data points, exposed to the process of triangulation and multiple subdivision of mesh of triangles.

PL

W artykule zaprezentowano modeler powierzchni swobodnych zaprojektowany i zaimplementowany z przeznaczeniem do wdrożenia w małych i średnich przedsiębiorstwach. System pracuje w dwóch niezależnych trybach: NURBS i Triangulacja. W trybie NURBS służy do modelowania gładkich powierzchni o ciągłej krzywiźnie, zadanych regularnymi siatkami punktów. W trybie Triangulacja (Mesh) służy do wprowadzania nieregularnych zbiorów punktów i generowania na ich podstawie powierzchni interpolujacej. Zadanie to rozwiązano za pomocą triangulacji, a następnie iteracyjnego zagęszczania siatek (tzw. subdivision) z użyciem zmodyfikowanej metody Butterfly. Zapis wyników działania w obu trybach do postaci plików DXF umożliwia przekazywanie danych do innych aplikacji, w celu ich późniejszego wykorzystania do analiz metodą elementu skończonego, w procesie obróbki zaprojektowanej powierzchni itp.

2

A review on advances of high-resolution solid state NMR spectroscopy in structural studies of polymer/clay nanocomposites

Olejniczak S., Kaźmierski S., Pallathadka P. K., Potrzebowski M. J.

Polimery

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2007

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T. 52, nr 10

713-721

EN

The new applications of one- and two-dimensional solid state (SS) NMR spectroscopy for investigations of polymer/clay nanocomposites were discussed. 1D SS NMR spectroscopy is applied to evaluate the structural and dynamic properties of composites. 2D SS NMR is used for detailed studies on polymer-nanofiller contacts what let understand the mechanism of these interactions on the molecular level.

PL

Omówiono nowe zastosowania jedno- (1D) i dwuwymiarowej (2D) spektroskopii magnetycznego rezonansu jądrowego w fazie stałej (SS NMR) w badaniach nanokompozytów polimer/glinka. Spektroskopię 1D SS NMR wykorzystuje się do oceny strukturalnych i dynamicznych właściwości kompozytów, a spektroskopię 2D - do szczegółowych badań oddziaływań polimer-nanonapełniacz, co pozwala na zrozumienie mechanizmu tych oddziaływań.

3

Badania polimorfizmu związków bioorganicznych metodami spektroskopii NMR w fazie stałej

Kaźmierski S., Potrzebowski M.J.

Wiadomości Chemiczne

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2006

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[Z] 60, 11-12

723-745

EN

Polymorphism is one of the most important and amazing phenomenon in structural chemistry. The knowledge of this phenomenon is crucial both in experimental sciences (e.g.: chemistry, physics and crystallography) and in industry - especially in pharmaceutical industry. It is well known, that polymorphic forms of therapeutic compounds differ in their bioavailability - e.g. the rate of dissolution and equilibrium solubility. In extreme cases, one polymorph may be a medicine whilst the second may be very dangerous or even poisonous. In this light, the possibility to distinguish the desirable form of compound from the useless form, seems to be very important. In our article, some problems concerning the investigation of polymorphism phenomenon by applications of solid-state NMR are presented. The possibilities of current NMR techniques in searching of polymorphism as well as the practical aspects and applications are presented and discussed.

4

Zastosowania spektroskopii magnetycznego rezonansu jądrowego w badaniach strukturalnych węglowodanów i ich pochodnych

Kaźmierski S.

Wiadomości Chemiczne

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2003

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[Z] 57, 5-6

339--365

EN

Carbohydrates play very important role in biological systems. Both carbohydrates and their derivatives are involved in many biological processes, such as cell-cell recognition, cell growth and energy transfer. In spite of very high importance in living processes, carbohydrates remain one of the less exploited class of biologically active molecules. There is a lot of different methods which can be used in carbohydrates analysis [1]. The Nuclear Magnetic Resonance (NMR) spectroscopy is one of the most attractive, important and powerful tool for analyzing the conformation and molecular architecture of carbohydrate molecules. This method serves the possibility of solving the majority of problems in this area, without any different methods – particularly in the liquid phase. The biggest advantage of NMR spectroscopy is that it is a nondestructive method. Both one- and two-dimensional NMR methods have provided valuable information about small and large molecules, ranging from the anomeric configuration of a monosaccharide to the sequence of monosaccharide residues in a bigger oligo- or polysaccharide compounds. After first years of applications mainly in primary carbohydrate structures, NMR spectroscopy has recently reached a level of sophistication, which allows both the structural and conformational analysis of carbohydrates in solution. This article reviews the applications and possibilities of current NMR techniques to the structural and conformational characterization of carbohydrate and its derivatives. Both 1D and 2D (COSY, HSQC, HSQC-TOCSY, HMBC) NMR spectra of the GOTCAB saponin 1 are presented as examples of utilization of NMR in the structure elucidation of the carbohydrate derivatives.

5

31P High Resolution solid State NMR Studies of Phosphoroorganic Compounds of Biological Interest

Potrzebowski M., Ganicz K., Kaźmierski S.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 8

1147-1169

EN

In this review several applications of 31P high resolution solid state NMR spectroscopy in structural studies of bioorganic samples is reported. The problem of pseudopolymorphism of bis[6-O,6_-O-(1,2:3,4-diisopropylidene-_-D-galactopyranosyl) phosphorothioyl] disulfide 1 and application of 31P CP/MAS experiment to investigate of this phenomenon is discussed. The influence of weak C-H___S intermolecular contacts on molecular packing of 1,6-anhydro-2-O-tosyl-4-S-(5,5-dimethyl-2-thioxa-1,3,2-dioxaphosphorinan-2-yl)- _-D-glucopyranose 2 and SP, RP diastereomers of deoxyxylothymidyl-3_-O-acetylthymidyl (3_,5_)-O-(2-cyanoethyl) phosphorothioate 3 and their implication on 31P NMR spectra is shown. The final part of review describes the recent progress in structural studies of O-phosphorylated amino acids (serine, threonine, tyrosine), relationship between molecular structure and 31P chemical shift parameters _ii and influence of hydrogen bonding on values of principal elements of chemical shift tensor.