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1

Mechanism and optimum pressure for sliding-mode nanogenerator

Yun Hang, He Ren

Polish Journal of Chemical Technology

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2023

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Vol. 25, nr 1

35--39

EN

Triboelectric nanogenerator has extensive applicability because of its capability of harvesting mechanical energy and flexible working modes. To research the optimum pressure and improve the recovered energy of the sliding-mode triboelectric nanogenerator, a contact model of the Al/PTFE tribo-pair is studied by ab initio calculation and finite element simulation. The F-atom of PTFE is proved to be the electron accepter and the charges transferred can be predicted by Bader charge analysis. The mathematical relation between interfacial distance, charges transferred and contact pressure can be fitted. By Gauss’s law, the electric field is simulated and the regeneration energy of the sliding-mode triboelectric nanogenerator can be evaluated by the total electric energy and friction loss. Finally, an optimum pressure can be set to the upper or lower limit of working pressure corresponding to larger recovered energy. And less friction coefficient and larger contact area are also effective methods for recovering energy.

2

Structural and mechanical properties of ZnTe in the zincblende phase

Soykan C., Ozdemir Kart S., Cagin T.

Archives of Materials Science and Engineering

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2010

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Vol. 46, nr 2

115-119

EN

Purpose: The aim of this work investigate to the structural and mechanical properties of ZnTe in the B3 structure, using the ab initio method based on Density Functional Theory (DFT). Design/methodology/approach: The Vienna ab initio Simulation Package (VASP) has been used to perform the electronic structure calculations. The projector-augmented wave formalism (PAW) implemented in this package leads to very accurate result comparable to other all-electron methods. The electronic exchange and correlation functions are treated within DFT by using generalized gradient approximation. Findings: The lattice parameter, bulk modulus, it's pressure derivative and the elastic stiffness coefficients are calculated. Our results for the structural parameters and the elastic constants at the equilibrium phase are in good agreement with the available experimental and other theoretical studies. We have also investigated the pressure dependence of mechanical properties for ZnTe in the structure of B3 to see this effect. Research limitations/implications: These compounds are convenient for many technological applications because of they have direct energy band gaps and property of light emitters at room temperature. Practical implications: These compounds used to many technological applications, such as solid state laser devices, photovoltaic devices, solar cells, remote control systems, thin films, transistors, THz emitter, detector and imaging systems etc. Originality/value: In this work, determination of structural and mechanical properties of ZnTe in the B3 structure at high pressures will lead to new technological applications of these materials.

3

The effects of boron impurity atoms on nickel ∑ 5 (012) grain boundary by first principles calculations

Kart H. H., Cagin T.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 30, nr 2

177-181

EN

Purpose: Impurity atoms in the grain boundary can be responsible for embrittlement or they can strengthen a material. In this work, we have modeled the effect of B impurity on ∑ 5 (012) symmetrical tilt grain boundary in Ni by using first principle quantum-mechanical calculations. The grains can either be pushed apart or pulled together depending on the size of the impurity and nature of the local relaxations. Design/methodology/approach: The calculations were carried out by using the Vienna ab-initio simulation package VASP with the projector augmented wave (PAW) potentials within generalized gradient approximation (GGA). K-space sampling is performed using a 2x2x1 Monkhorst Pack scheme for Brillouin-zone integration in all model systems. The Methfessel-Paxton smearing method with 0.1 eV smearing width is used for the determination of partial occupancies for each wave function. Findings: It is found that the extension of the nickel grain boundary is due to the repulsion of the segregated and neighboring B atoms. Moreover, the effects of tensile strength loaded uniaxially along the (012) direction are analyzed when the impurity atoms of B are substituted into the ∑ 5 (012) symmetrical tilt grain boundary in Ni. Our calculations are compatible with the other first principle calculations. Research limitations/implications: Cohesive energy calculations indicate that interstitial sites are preferred to substitutional sites and that B leads to cohesive enhancement. Originality/value: The effects of boron impurity atoms on nickel ∑ 5 (012) grain boundary by first principles calculations were evaluated.

4

Water cage clusters (H2O)n, from n=6 to 12: do they model liquid water?

Sadlej J., Buch V.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 4

403-422

EN

The optimal structures, the interaction energies, the OH stretch and HOH bending frequencies of water cage clusters (H(2)O)n, n = 6-12 have been investigated by ab initio method (MP2/DZ level). The clusters correspond to the relatively regular cage structures characterized by distinct groups of O...O bond lengths and HOH angles. As a result, the OH stretch spectrum contains well separated DAA and DDA bands red-shifted by hundreds of cm(-1) with respect to water monomer and a third band for the dangling OH at the "crystal like" clusters. The "amorphous like" clusters yield numerous hydrogen bonded bands in a broad spectral range. The new spectral feature in the gap between DDA and DAA bands at the OH stretch region is the presence of the new lines due to four-coordinated DDA A water molecules for (H(2)O)(12) cluster. In contrast to the OH stretch, the vibrational bending frequencies are blue-shifted by 40-170 cm (-1) with respect to H(2)O(g). Features due to different structural elements were identified.

5

Experimental and theoretical study on proton tunneling in jet-cooled 9-hydroxyphenalenone-CO2 van der Waals complex

Mori H., Furusawa J., Sekiya H.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 4

451-462

EN

The fluorescence excitation, dispersed fluorescence, and hole-burning spectra of the 9-hydroxyphenalenone (9HPO)-C(2) 1:1 complex have been measured to investigate the effects of the van der Waals interaction on proton tunneling in the So state. The Si-So electronic origin is only 4 cm (-1) red-shifted with respect to that of the monomer, suggesting that proton tunneling occurs in both the So and Si states of the 9HPO-CO(2) complex, although the tunneling splittings have not been observed in the excitation spectrum. The structure of the observed complex and its tunneling potential for the So state of 9HPO have been theoretically investigated by using the reaction surface Hamiltonian method. The intermolecular interaction significantly changes the shape of two dimensional potential energy surface along the reaction coordinates, and slightly decreases the tunneling splitting in the zero-point level.

6

Synthesis of Crotonoyl, Cynamoyl and p-Methoxycynamoyl Derivatives of Camphoric Imide : Crystal and Molecular Structure

Matraszek J., Mieczkowski J., Cyrański M.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 4

477-482

EN

Three derivatives of camphoric acid imide (crotonyl, cynamoyl and p-methoxycynamoyl) have been synthesized. Despite of a small number of heavy atoms, the absolute structure determination occured to be successful.

7

Furo[2,3-b]pyrrole Derivatives : Syntheses and Reactions in the Furan and Pyrrole Ring

Sleziak R., Krutosikova A., Cyrański M., Krygowski T.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 2

207-217

EN

6-Substitued furo[2,3-b] pyrrole-5-carboxylic acids 2b-d as well as their 2-formyl-substitued derivatives 4a-d have been prepared by alkaline hydrolysis of the corresponding esters 1b-d and 3a-d, respectively. A different behaviour of methyl 6H-furo[2,3-b]pyrrole-5-carboxylate 1a in comparison with the 4Hfuro[3,2-b] pyrrole isomer has been discussed in a framework of different acidity of proton of NH group. The hypothesis has been supported by ab initio B3LYP/6-311+G**DTF calculations. The 2-formylated derivatives 3b-d were used for synthesis the propenoid acids 5b-d, the corresponding acid azides 6b-d, new disubstitued ureas 9 or 10, 2-cyano-derivatives 11a-d, which were transfored into the corresponding amidines 12 and substitued arylureas 13 as well as to 5'-tetrazolyl derivative 14. Further methyl 2-triphenylmethyl-6Hfuro[2,3-b]pyrrole-5-carboxylate 15 and its Michael addition product 16 were prepared.

8

Ab Initio Calculations of the Pairing of Four Canonical DNA Bases with Three Thymine Derivatives Generated by Hydroxyl Radical in Anaerobic Conditions

Cysewski P.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 2

245-256

EN

The coding properties of three hydroxyl radical induced thyine derivatives; 5-hydroxy-6-hydrothyine (1), 5,6-dihydrothymine (2) and 6-hydroxy-5,6-dihydrothymine (3) were characterized by ab initio HF/6-31 G, HF/6-31 G**//HF/6-31G and SCI-PCM/6-31G**//HF/6-31G quantum chemistry calculations. All studied derivatives ay have potential miscoding character, which strongly depends on the polarity of the environment. Under non-polar conditions all analyzed thymine derivatives are able to pair with guanine, what may result in the T-C transition. Additionally, I is able to form stable pairs with cytosine and adenine. Compound 3 is capable to pair with all four canonical DNA bases. All these pairs are more stable than standard AT pair. In polar environment the pairing potential of studied thymine derivatives is significantly reduced. However, the mispairing potential is usually the same and reained significant, especially for 6-hydroxy-6-hydrothymine.

9

Intermolecular (OHO)- hydrogen bond formed by a hydroxyquinoline derivative

Wiench J. W., Stefaniak L., Grech E.

Bulletin of the Polish Academy of Sciences. Chemistry

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1999

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Vol. 47, No. 1

67-75

EN

(1)H, (13)C, (14)N, (15)N, (17)0, and (19)F NMR data are presented for HTFMQ and its complexes with DMAN in 2 .land 1 : 1 molar ratios. GIAO-CHF molecular orbital calculations for the [1H] and [4H] forms of the free molecule and its anion are also performed. The results show that the [4H] form of HTFMQ predominates in acetonitrile solutions. In both complexes with DMAN, HTFMQ forms a semi-anion containing an intermolecular hydrogen bond.

10

Ab initio calculations of the 29Si NMR chemical shifts of simple silicon compounds

Cypryk M.

Bulletin of the Polish Academy of Sciences. Chemistry

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1999

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Vol. 47, No. 1

33-40

EN

Two methods of (29) Si NMR calculations, GIAO-HF and GIAO-B3LYP /6-311+G(2d,p) were compared for a series of simple silicon compounds. The (29) Si isotropic chemical shifts obtained by both methods are in reasonable agreement with the experi-ment, although the GIAO-HF method predicts the chemical shifts slightly more precisely. The accuracy is generally worse than that reported for (13)C chemical shifts calculations.

11

An ab initio calculation of the vibrational spectrum of pyridine N-oxide and pyridine-d-5 N oxide

Szafran M., Koput J.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 2

368-376

EN

Density functional theory (using Becke's exchange and Lee-Young-Parr's correlation fanctionals (BLYP) and ab initio second-order Moller-Plesset (MP2) calculations were carried out in order to investigate the molecular structure and vibrational spectra of pyridine N-oxide and its perdeuterated analog. The calculated structural and spectral features are in good agreement with the available experimental results. Most of the BLYP/6-31G(d,p) and MP2/6-31G(d,p) non-CH stretching frequencies are slightly lower than the reliable experimental assignments; the mean deviations are 23 and 21 cm(-), respectively. On the basis of agreement between calculated and experimental results, assignments of the fundamental vibrational modes were examined and some reassignments were proposed.