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Tytuł:
Statistical properties of a polymer chain in the environment with low concentration of nanoparticles
Autorzy:
A. Tsehay, Dessalegne
Luo, Meng-Bo
Powiązania:
https://bibliotekanauki.pl/articles/1050809.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
diffusion
conformation
polymer chain
nanoparticles
molecular dynamics
Opis:
We have investigated the statistical properties of polymer in the environment with low concentration of nanoparticles by using large-scale molecular dynamics simulations. The scaling law for the mean square radius of gyration was examined and simulation results for the polymer lengths 64≤N≤144 yielding a reasonably accurate value of the Flory exponent ν=0.58 at weak polymer-nanoparticle interaction ε_{PN}. Within the same range of N, the mean asphericity of the chain is independent of N. We found that the polymer behaves like a self-avoiding walk chain at small ε_{PN} and a compact sphere at large ε_{PN}. The results are attributed to the increase in the contact between polymer and nanoparticles with increasing ε_{PN}. Normal diffusions of polymer are always observed at whatever ε_{PN} and size and concentration of nanoparticles. Our result shows that the normal diffusion behavior of polymer is independent of polymer's state even though there is a phase transition from a desorbed polymer phase at small ε_{PN} to an adsorbed polymer phase at large ε_{PN}.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1274-1280
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling drug-receptor interactions in an average binding site for NK2
Autorzy:
Alagona, G.
Ghio, C.
Monti, S.
Powiązania:
https://bibliotekanauki.pl/articles/1953954.pdf
Data publikacji:
1998
Wydawca:
Politechnika Gdańska
Tematy:
receptor modelling
docking
non covalent interactions
molecular mechanics
molecular dynamics
substituent effects
Opis:
A tentative procedure applied to the search for a new antagonist of neurokinin A (NKA) is presented. In parallel a tentative 3-D model of the NK2 receptor was created, using bacteriorhodopsin (BRD) as a template. The residue substitutions were performed in BRD to obtain the sequence for NK2R_H and the seven a-helical segments were optimized forcing the a-helical backbone to match the corresponding aligned parts of BRD, while the arrangements of the side chains were model built based on available site-directed mutagenesis studies. Constrained MM and molecular dynamics simulations were carried out H-bonding a low energy conformer of the known drugs to residues in the receptor site, allowing both the receptor site and drugs to relax. The Connolly surface for each ligand allowed to determine an "average" binding site in which all the low energy conformers of known and prospective drugs were docked and classified according to a statistical index. The whole procedure was repeated exploiting the lately published structure of an actual G protein coupled receptor as a better template, thus producing a cavity in the binding site to directly dock the drugs. Corollary validations of the force fields used are also mentioned. In addition intra- and intermolecular interactions suitable to produce more active drugs were evaluated.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1998, 2, 4; 563-581
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative stability analysis of D23N mutated Aβ
Autorzy:
Alred, E. J.
Scheele, E. G.
Berhanu, W. M.
Hansmann, U. H. E.
Powiązania:
https://bibliotekanauki.pl/articles/1935815.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska
Tematy:
Aβ
structural polymorphism
molecular dynamics
parallel and anti-parallel β sheets
Iowa mutant
Opis:
Amyloid β (Aβ) is the subject of numerous studies due to its link to the devastating Alzheimer’s disease and it exists in a parallel structure in fibril aggregate. The Iowa mutant (D 23 N) Aβ posses a unique antiparallel fibril aggregate structure and can also form parallel structure. This structural difference, coupled with the fact that occurrence of the Iowa mutant is correlated with early onset Alzheimer’s, suggests to use these peptides as candidates for computational studies of the structural determinants of the toxicity of Alzheimer’s disease. In order to compare the two observed Aβ structural motifs, we designed a computational study to probe the factors that affect the stability of parallel and antiparallel aggregates. Since the structural changes may occur on a timescale beyond that sampled in traditional molecular dynamics (MD), we employed a techniques of scaling the mass to reduce the solution ’s viscosity and compared the results to regular molecular dynamics. The knowledge gained from this study could provide insight into the mechanism of selection for antiparallel and parallel two fold structures.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2014, 18, 4; 365--371
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, characterization and molecular dynamics simulation of dendronized poly(3,5-diphthalimidoalkylphenyl methacrylate)s
Synteza, charakterystyka i symulacje metodą dynamiki molekularnej dendrymerycznych poli(metakrylanów 3,5-diftalimidoalkilofenylu)
Autorzy:
Alvarado, N.
Alegría, L.
Sandoval, C.
Gargallo, L.
Leiva, A.
Radic, D.
Powiązania:
https://bibliotekanauki.pl/articles/946840.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
poly(phtalimidoalkyl methacrylate)
dendronized polymers
spacer groups
molecular dynamics simulation
radius of gyration
end-to-end distance
poli(metakrylan ftalimidoalkylu)
polimery dendrymeryczne
grupy dystansujące
symulacja metodą dynamiki molekularnej
promień bezwładności
odległość między końcami łańcucha
Opis:
Dendronized methacrylates containing 3,5-diphthalimidoalkylphenyl moieties (with ethyl, propyl or butyl spacer groups) were synthesized. These monomers were then polymerized using radical polymerization. Monomers and polymers were characterized using Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance methods (1H NMR and 13C NMR). Molecular weight was estimated by multi-angle static light scattering (MALS). Molecular dynamics simulation was performed to evaluate the conformational radius of gyration (Rg) and the end-to-end distance (ree). Different spatial arrangements depending on the length of the spacer group are observed.
Zsyntezowano dendrymeryczne metakrylany zawierające ugrupowania 3,5-diftalimidoalkilofenylowe (z etylowymi, propylowymi lub butylowymi grupami dystansującymi), a następnie monomery te poddano polimeryzacji rodnikowej. Do określenia struktury wyjściowych monomerów oraz otrzymanych polimerów zastosowano spektroskopię w podczerwieni z transformacją Fouriera (FT-IR) i metody magnetycznego rezonansu jądrowego (1H NMR i 13C NMR). Oznaczono również masę cząsteczkową polimerów metodą wielokątowego rozpraszania światła (MALS). Symulacje metodą dynamiki molekularnej pozwoliły na wyznaczenie konformacyjnych promieni bezwładności (Rg), a także odległości między końcami łańcucha (ree). Zaobserwowano różne układy przestrzenne, których rodzaj zależał od wielkości grupy dystansującej.
Źródło:
Polimery; 2016, 61, 1; 10-15
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluctuations of kinetic energy at molecular dynamics and the atomic interactions in crystals
Autorzy:
Andriyevsky, B.
Piekarski, J.
Andriyevska, L.
Powiązania:
https://bibliotekanauki.pl/articles/118444.pdf
Data publikacji:
2018
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
interatomic interactions
molecular dynamics
silicon
phonon relaxation time
oddziaływania międzyatomowe
dynamika molekularna
krzem
czas relaksacji fononów
Opis:
The calculation method of the molecular dynamics has been applied to study the correlation of the kinetic energy fluctuations and the relaxation time of the velocity autocorrelation function and the phonon relaxation time in a crystal. On the basis of the molecular dynamics data for silicon crystal obtained at different temperatures in the range 200 K – 1000 K the correlation between the kinetic energy fluctuations and the relaxation time of the velocity autocorrelation function has been calculated with the relatively high coefficient of determination R2 = 0.9396. The correlation obtained and the corresponding approach substantiate a use of the kinetic energy fluctuations for the calculation of values related to the heat conductivity in the silicon based semiconductors (coefficients of thermal conductivity and diffusivity).
Obliczeniowa metoda dynamiki molekularnej została zastosowana do badania korelacji fluktuacji energii kinetycznej i czasu relaksacji autokorelacyjnej funkcji prędkości i czasu relaksacji fononów w krysztale. Na bazie danych dynamiki molekularnej kryształu krzemu otrzymanych w różnych temperaturach w zakresie 200 K – 1000 K została obliczona korelacja fluktuacji energii kinetycznej i czasu relaksacji autokorelacyjnej funkcji prędkości, która cechuje się stosunkowo wysokim współczynnikiem determinacji R2 = 0.9396. Otrzymana korelacja uzasadnia zastosowanie fluktuacji energii kinetycznej do badań obliczeniowych wielkości powiązanych z przewodnością cieplną półprzewodników na bazie krzemu (współczynniki przewodności i dyfuzyjności cieplnej).
Źródło:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej; 2018, 12; 19-24
1897-7421
Pojawia się w:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of phonon relaxation time for silicon by means of using the velocity autocorrelation function of atoms in molecular dynamics
Autorzy:
Andriyevsky, Bohdan
Maliński, M.
Buryło, Ł.
Stadnyk, V. Y.
Romanuk, M. O.
Piekarski, J.
Andriyevska, L.
Powiązania:
https://bibliotekanauki.pl/articles/201222.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silicon
molecular dynamics
relaxation time of the velocity autocorrelation function
coefficient of thermal diffusivity
krzem
dynamika molekularna
Opis:
Results of the ab initio molecular dynamics calculations of silicon crystals are presented by means of analysis of the velocity autocorrelation function and determination of mean phonon relaxation time. The mean phonon relaxation time is crucial for prediction of the phonon-associated coefficient of thermal conductivity of materials. A clear correlation between the velocity autocorrelation function relaxation time and the coefficient of thermal diffusivity has been found. The analysis of the results obtained has indicated a decrease of the velocity autocorrelation function relaxation time t with increase of temperature. The method proposed may be used to estimate the coefficient of ther-mal diffusivity and thermal conductivity of the materials based on silicon and of other wide-bandgap semiconductors. The correlation between kinetic energy fluctuations and relaxation time of the velocity autocorrelation function has been calculated with the relatively high coefficient of determination R2 = 0.9396. The correlation obtained and the corresponding approach substantiate the use of kinetic energy fluctuations for the calculation of values related to heat conductivity in silicon-based semiconductors (coefficients of thermal conductivity and diffusivity).
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 3; 651-656
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zinc ion adsorption on carbon nanotubes in an aqueous solution
Autorzy:
Ansari, A.
Mehrabian, M. A.
Hashemipour, H.
Powiązania:
https://bibliotekanauki.pl/articles/779155.pdf
Data publikacji:
2012
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
adsorption
molecular dynamics simulation
heavy metals
electrostatic force
interaction energy
functional groups
Opis:
The literature devoted to numerical investigation of adsorption of heavy metal ions on carbon nanotubes is scarce. In this paper molecular dynamics is used to simulate the adsorption process and to investigate the effect of the infl uencing parameters on the rate of adsorption. The predictions of the molecular dynamics simulation show that the adsorption process is improved with increasing the temperature, pH of solution, the mass of nanotubes, and surface modifi cation of CNT using hydroxyl and carboxyl functional groups. The results predicted by the model are compared with the experimental results available in the literature; the close agreement validates the accuracy of the predictions. This study reveals that the water layers around the carbon nanotubes and the interaction energies play important roles in the adsorption process. The study also shows that electrostatic force controls the attraction of zinc ions on the nanotube sidewall.
Źródło:
Polish Journal of Chemical Technology; 2012, 14, 3; 29-37
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation and molecular dynamics simulation of muscovite with mixed anionic/cationic collectors
Autorzy:
Bai, Yang
Li, Caixia
An, Hongyun
Wang, Guoliang
Zhao, Xin
Zhang, Jinqi
Powiązania:
https://bibliotekanauki.pl/articles/110125.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
muscovite
mixed anionic/cationic collectors
flotation
molecular dynamics simulation
Opis:
In this study, three kinds of anionic collectors (sodium oleate (NaOl), sodium dodecyl sulfonate (SDS) and naphthenic acid (NA)) were used in combination with dodecylamine (DDA) to investigate the flotation behavior of muscovite under the action of different mixed anionic/cationic collectors, and their mechanisms for adsorption on the muscovite (001) Surface were clarified using molecular dynamics simulations. The flotation results indicated that different mixed anionic/cationic collectors could improve the recovery of muscovite to varying degrees, but the optimum molar ratio of anionic collectors to DDA and the optimum mixed collector dosage were different. Molecular dynamics simulations showed that the mixed anionic/cationic collectors could significantly increase the hydrophobicity of the muscovite, as evidenced by the decrease in the calculated water molecule density on the muscovite surface and the diffusion coefficient of water molecules at the solid/liquid interface. The interaction between the amino group and the polar group of anionic collectors reduced the electrostatic repulsion between DDA cations and theoretically increased the adsorption capacity of the mixed anionic/cationic collectors on the muscovite surface. Moreover, DDA/NA and DDA/NaOl could improve the calculated carbon atom density on the muscovite surface, which enhanced the hydrophobic association between nonpolar carbon chains, thus further achieving an enhanced flotation performance.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 2; 313-324
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synergistic mechanism of dodecylamine/octanol mixtures enhancing lepidolite flotation from the self-aggregation behaviors at the air/liquid interface
Autorzy:
Bai, Yang
Xu, Mengxu
Wen, Weixiang
Zhu, Shifei
Mo, Weichen
Yan, Pingke
Powiązania:
https://bibliotekanauki.pl/articles/27323641.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
DDA/OCT mixtures
self-aggregation behaviors
flotation foam
molecular dynamics simulations
surface tension
air interface
liquid interface
Opis:
Surface tension measurements and molecular dynamics (MD) simulations were used to explore the flotation foam properties and self-aggregation behaviors of dodecylamine (DDA)/octanol (OCT) mixtures formed with different mole ratios at the air/liquid interface. Based on the surface and thermodynamic parameters, the DDA/OCT mixtures exhibited greater interfacial activities and adsorption capacities than their individual components. The MD simulations showed that DDA and OCT were aggregated through hydrogen bonding, coulombic forces and hydrophobic association. OCT was inserted into the DDA adsorption layer, causing the alkyl chains of both DDA and OCT to extend from water to air at varying heights and angles. The addition of OCT improved the hydration of the amino groups and reduced the overall number of hydrogen bonds. The stability of the flotation foam decreased, and the high viscosity and difficult defoaming of the DDA flotation foam were significantly improved. When the DDA/OCT mole ratio was 2:1, the included angle formed between the alkyl chains and the interface was maximized, leading to enhanced compatibility among the alkyl chains, and the hydrogen bond energy was relatively large, which showed a strong synergistic effect. The MD simulation findings were consistent with the results obtained from the lepidolite flotation and surface tension experiments conducted in this study; our results could provide a theoretical foundation for the selection of superior mixed collectors and frothers.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 176510
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular dynamics simulation of copolymers
Autorzy:
Banaszak, M.
Powiązania:
https://bibliotekanauki.pl/articles/1964087.pdf
Data publikacji:
2001
Wydawca:
Politechnika Gdańska
Tematy:
molecular dynamics
computer simulation
copolymer
diblock
ionic copolymer
diffusion
structure factor
equation of state
thermodynamic properties
Opis:
A series of representative molecular dynamics simulations of model Lennard-Jones copolymer chains is presented. We report measurements of thermodynamic, structural and dynamic properties of our model copolymers. For neutral copolymers we confirm our version of thermodynamic perturbation theory of the first order, while for ionic copolymers we demonstrate microphase formation and the anisotropy of the counterion diffusion.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 1; 17-27
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new program package for structural analysis of computer simulated solids
Autorzy:
Bergmański, G.
Rybicki, J.
Mancini, G.
Powiązania:
https://bibliotekanauki.pl/articles/1954546.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
ring analysis
structure of matter
molecular dynamics
computer modelling
Opis:
The opportunity to gain detailed information on representative set of rings and chains of atoms is of great importance in the analysis of medium-range order in the computer simulated structures of solids. A new program package (ANELLI) for ring and chain analysis of computer simulated atomic structures is presented. The paper includes detailed description of input and output files. The package presentation is followed by exemplary results obtained using our programs.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 4; 555-573
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new program package for structural analysis of computer simulated solids
Autorzy:
Bergmański, G.
Rybicki, J.
Mancini, G.
Powiązania:
https://bibliotekanauki.pl/articles/1954549.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
ring analysis
structure of matter
molecular dynamics
computer modelling
Opis:
The opportunity to gain detailed information on representative set of rings and chains of atoms is of great importance in the analysis of medium-range order in the computer simulated structures of solids. A new program package (ANELLI) for ring and chain analysis of computer simulated atomic structures is presented. The paper includes detailed description of input and output files. The package presentation is followed by exemplary results obtained using our programs.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 4; 555-573
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synergic Effect of sodium oleate (NaOL) and benzohydroxamic acid (BHA) on flotation of wolframite
Autorzy:
Bu, H.
Cao, M.
Gao, Y.
Huang, H.
Powiązania:
https://bibliotekanauki.pl/articles/110377.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wolframit
mixed collector
molecular dynamics
synergic effect
Opis:
In this work, two collectors sodium oleate (NaOL) and benzohydroxamic acid (BHA) were used to study the synergic effect in wolframite flotation. The flotation behaviour of these collectors was investigated at various NaOL:BHA ratios. Results show that the mixtures of NaOL with BHA of different ratios result in large improvements in the recovery of wolframite and the 9:1 NaOL:BHA ratio of collector mixture produced the highest wolframite recovery. The amount of NaOL and BHA adsorbed on wolframite was measured for these various reagent mixtures. Compared with pure NaOL, the addition of a certain proportion of BHA is beneficial for NaOL adsorption. Molecular dynamics simulations indicate the formation of HOL–HA (oleic acid–benzohydroxamic acid) complex can take place spontaneously in NaOL–BHA system. Additionally, HOL–HA complex interact with the huebnerite (MnWO4) surface more easily than NaOL–HOL (the highest surface active composition in sodium oleate) and the addition of BHA enable the H of carboxyl group in HOL to generate hydrogen bonds with O atoms of huebnerite surface, resulting in a stronger affinity of mixed surfactants. These results reveal that in a binary NaOL–BHA system, the BHA can encourage greater adsorption of the NaOL.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 82-93
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The interaction of poly(L-lactic acid) and the nucleating agent N,N-bis(benzoyl) suberic acid dihydrazide
Interakcje między poli(kwasem L-mlekowym) a czynnikiem zarodkującym —N,N-bis(benzoilo)dihydrazydem kwasu suberynowego
Autorzy:
Cai, Y.-H.
Zhao, L.-S.
Powiązania:
https://bibliotekanauki.pl/articles/947457.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
poly(L-lactic acid)
nucleating agent
crystallization
nucleation mechanism
molecular dynamics simulation
poli(kwas L-mlekowy)
czynnik zarodkujący
krystalizacja
mechanizm zarodkowania
symulacja metodą dynamiki molekularnej
Opis:
Since N,N'-bis(benzoyl) suberic acid dihydrazide [NA(S)] acts as a powerful nucleating agent for poly(L-lactic acid) (PLLA), it is necessary to study the nucleation mechanism of NA(S) in the crystallization of PLLA. The interaction between PLLA and NA(S) was investigated by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and temperature-dependent Raman spectroscopy. The results from FT-IR and temperature-dependent Raman spectroscopy showed that a hydrogen bond between the C=O of PLLA and the N-H of NA(S) was formed. The TGA also indicated the existence of an intense interaction between PLLA and NA(S), resulting in the potent nucleation ability of NA(S) for PLLA. Molecular dynamics simulations (MDS) were employed to simulate the interaction of PLLA on the NA(S) surface. The simulation results further confirmed the hydrogen bond between PLLA and NA(S). The MDS study also analyzed the interaction energy between PLLA and NA(S). The MDS results can be used to select the proper nucleating agents and design novel organic nucleating agents.
Zbadano mechanizm zarodkowania przy użyciu N,N'-bis(benzoilo)dihydrazydu kwasu suberynowego [NA(S)] w procesie krystalizacji poli(kwasu L-mlekowego) (PLLA). Interakcje między cząsteczkami PLLA i NA(S) oceniano na podstawie spektroskopii w podczerwieni z transformacją Fouriera, analizy termograwimetrycznej oraz widm Ramana, rejestrowanych w różnej temperaturze. Stwierdzono, że pomiędzy tlenem z grupy C=O w łańcuchu PLLA a wodorem z grupy N-H obecnej w NA(S) tworzą się wiązania wodorowe. Analiza TGA wykazała, że ww. intensywne interakcje są wynikiem dużej zdolności NA(S) do zarodkowania krystalizacji PLLA. Do zbadania oddziaływań na powierzchni NA(S) zastosowano także symulacje metodą dynamiki molekularnej (MDS), które potwierdziły występowanie wiązań wodorowych PLLA/NA(S). Metodą MDS określono też energię interakcji (technika MDS może być wykorzystana przy wyborze środka zarodkującego odpowiedniego dla danego układu).
Źródło:
Polimery; 2015, 60, 11-12; 693-699
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of the static and dynamic properties of tho-type silicates
Autorzy:
Cauchi, R.
Grima, J. N.
Powiązania:
https://bibliotekanauki.pl/articles/1954447.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska
Tematy:
auxetics
zeolites
thomsonite
molecular dynamics
Opis:
Auxetic materials are materials exhibiting a negative Poisson’s ratio in one of their planes. This phenomenon has been studied in various materials. Zeolites are crystalline substances whose structure is characterised by the framework of linked tetrahedra, each consisting of four oxygen atoms surrounding a cation. The resulting interstitial spaces make them efficient for use as adsorbents and molecular sieves, and many studies have been focused on this aspect. Some of these zeolites may exhibit auxeticity at least in one of their planes. THO (and similar systems, such as NAT and EDI) together with the all-silica equivalent of these have been studied extensively via static simulations for their negative Poisson’s ratio in the (001) plane. In this paper a study of the all-silica equivalent of THO has been carried out via both static and dynamic simulations using the same force-field, where the system was subjected to stress along the x direction. The hypothesised semi-rigid mechanism of deformation, proposed by Grima et al. was then projected over this framework. The results obtained confirmed auxeticity along this plane by means of the COMPASS force-field, in both static and dynamic studies and compared well with the proposed mechanism of semi-rigid rotating polygons. It also showed that as the Young’s modulus of this mechanism increases other mechanisms of deformation increase in importance.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2014, 18, 1; 5-65
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 100

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