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Journal articles on the topic 'Atom sizes'

Author: Grafiati

Published: 28 May 2022

Last updated: 31 July 2025

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1

Sachdev, A., and R. I. Masel. "Embedded atom calculations of the equilibrium shapes of 5–60 atom palladium nanocrystals." Journal of Materials Research 8, no. 3 (1993): 455–61. http://dx.doi.org/10.1557/jmr.1993.0455.

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The embedded atom method (EAM) has been used to compare the stability of a series of small palladium clusters with 5–60 atoms and a variety of shapes. It is found that the 13- and 55-atom icosahedra and cubo-octahedra are stable at 0 K. However, other sized icosahedra and cubo-octahedra are unstable at 0 K. Upon annealing, the icosahedra and cubo-octahedra reconstruct into nonpolyhedral structures which are highly strained. The strained structures are much more stable than the icosahedron or cubo-octahedron except when there are 13 or 55 atoms in the cluster. Further, there are many disordered

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2

Rattanamongkhonkun, Kanya, Radom Pongvuthithum, and Chulin Likasiri. "Rearrangement of Single Atoms by Solving Assignment Problems via Convolutional Neural Network." Applied Sciences 14, no. 17 (2024): 7877. http://dx.doi.org/10.3390/app14177877.

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This paper aims to present an approach to address the atom rearrangement problem by developing Convolutional Neural Network (CNN) models. These models predict the coordinates for atom movements while ensuring collision-free transitions and filling all vacancies in the target array. The process begins with designing a cost function for the assignment problem that incorporates constraints to prevent collisions and guarantee vacancy filling. We then build and train CNN models using datasets for three different grid sizes: 10×10, 13×13, and 21×21. Our models achieve high accuracy in predicting ato

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3

O'Keefe, Michael, and N. E. Brese. "Atom sizes and bond lengths in molecules and crystals." Journal of the American Chemical Society 113, no. 9 (1991): 3226–29. http://dx.doi.org/10.1021/ja00009a002.

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4

Hossain, M. J., M. R. I. Faruque, M. T. Islam, and S. S. Islam. "An effective medium ratio obeying meta-atom for multiband applications." Bulletin of the Polish Academy of Sciences Technical Sciences 65, no. 2 (2017): 139–47. http://dx.doi.org/10.1515/bpasts-2017-0017.

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Abstract In this paper, an effective medium ratio obeying, negative refractive index, compact meta-atom was designed, manufactured and tested for operation in a multiband microwave regime. The proposed meta-atom structure obeyed better effective medium ratio. The results of the measurement were verified by the commercially available Computer Simulation Technology (CST) Studio Suite 2014 simulator. The effective medium ratio obeying meta-atom displayed multiband response, in conjunction with negative refractive index property over a certain frequency band in the microwave frequency span. Furthe

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5

Zhang, Haijun, Keisuke Kawashima, Mitsutaka Okumura, and Naoki Toshima. "Colloidal Au single-atom catalysts embedded on Pd nanoclusters." J. Mater. Chem. A 2, no. 33 (2014): 13498–508. http://dx.doi.org/10.1039/c4ta01696c.

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6

Martin, Thomas E., Robert W. Mitchell, Edward D. Boyes, and Pratibha L. Gai. "Atom-by-atom analysis of sintering dynamics and stability of Pt nanoparticle catalysts in chemical reactions." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2186 (2020): 20190597. http://dx.doi.org/10.1098/rsta.2019.0597.

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Supported Pt nanoparticles are used extensively in chemical processes, including for fuel cells, fuels, pollution control and hydrogenation reactions. Atomic-level deactivation mechanisms play a critical role in the loss of performance. In this original research paper, we introduce real-time in-situ visualization and quantitative analysis of dynamic atom-by-atom sintering and stability of model Pt nanoparticles on a carbon support, under controlled chemical reaction conditions of temperature and continuously flowing gas. We use a novel environmental scanning transmission electron microscope wi

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7

Watanabe, Shunta, Yoko Tomita, Kohei Kawabata, and Takashi Nakayama. "Clustering feature of metal atoms in pentacene molecular solids: a first-principles study." Japanese Journal of Applied Physics 61, no. 2 (2022): 021003. http://dx.doi.org/10.35848/1347-4065/ac41e2.

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Abstract Metal-atom contamination often induces the degradation of organic molecular devices. In this work, we studied the clustering feature of Au and Al impurity metal atoms in pentacene solids by first-principles calculations. We found that Au atoms prefer to produce clusters in a molecule-edge space due to the strong bonding among Au atoms, and such clusters can increase their sizes by producing molecule vacancies. On the other hand, the Al atom prefers to locate separately around the center of pentacene molecules due to the strong bonding between the Al atom and surrounding molecules, whi

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8

Banerjea, Amitava, Radhika Prosad Datta, Abhijit Mookerjee, and A. K. Bhattacharyya. "Determination of the Ground State Geometries of Copper Clusters by Simulated Annealing." International Journal of Modern Physics B 11, no. 19 (1997): 2333–41. http://dx.doi.org/10.1142/s0217979297001192.

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We determine the lowest energy structures of small (10–20 atoms) copper clusters. The semi-empirical Equivalent Crystal Theory (ECT) is used in conjunction with the Metropolis Monte Carlo algorithm to determine the equilibrium geometry of each cluster via simulated annealing. The optimum structures of the clusters in this size range are found to be derived from icosahedral structures. The 13-atom cluster is an icosahedron and the 19-atom one a double-icosahedron. The other sizes show structures related to these. The 10- and 11-atom clusters, however, show somewhat different structures. We repo

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9

Nakhaei Pour, Ali, Javad Karimi, Zahra Keyvanloo, and Mohamadreza Hashemian. "Size Dependence Adsorption of Hydrogen on Cobalt Clusters: A DFT Study." Journal of Nano Research 42 (July 2016): 100–111. http://dx.doi.org/10.4028/www.scientific.net/jnanor.42.100.

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Density functional theory was used to investigate the effect of size on the adsorption state of hydrogen atom on small cobalt particles. For this propose, we have performed series of DFT-GGA calculations on various sizes of Co clusters, between 4 and 24 atoms, and a Co FCC (100) slab, with and without hydrogen atom adsorbate. The results showed that the destabilization and the cohesive energies per atom in a metal cluster are represented as linear function of the surface-to-volume ratio of the metal clusters. In addition, the energy of the HOMO–LUMO gap from 4s and 3d valence orbitals of the c

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10

Zhang, Hongtao, Wen Wang, Jun Sun, Li Zhong, Longbing He, and Litao Sun. "Surface-Condition-Dependent Deformation Mechanisms in Lead Nanocrystals." Research 2022 (July 27, 2022): 1–7. http://dx.doi.org/10.34133/2022/9834636.

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Serving as nanoelectrodes or frame units, small-volume metals may critically affect the performance and reliability of nanodevices, especially with feature sizes down to the nanometer scale. Small-volume metals usually behave extraordinarily in comparison with their bulk counterparts, but the knowledge of how their sizes and surfaces give rise to their extraordinary properties is currently insufficient. In this study, we investigate the influence of surface conditions on mechanical behaviors in nanometer-sized Pb crystals by performing in situ mechanical deformation tests inside an aberration-

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11

Zhang, Xiu Rong, Lin Yin, Wei Jun Li, and Hui Shuai Tang. "Theory Study on the Geometric Structures and Electronic Properties of Pt_nN^0,±(n=1-5) Clusters." Advanced Materials Research 516-517 (May 2012): 1889–92. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1889.

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The geometric structures of PtNN0,± clusters are optimized by the B3LYP/LANL2DZ method of density function theory, the ground state structures are obtained, and the electronic structure are studied. The results show: the N atoms gain the charge when the clusters are formed, but some Pt atoms gain the charge and other Pt atoms lose the charge. N atom and Pt atom have internal heterozygous, and the spd hybridized between Pt atoms and N atoms are increasing with cluster s’ sizes.

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12

Rouser, Mason A., and Harry W. Gibson. "Desymmetrization of disubstituted aromatic crown ethers via intramolecular Cannizzaro reactions." New Journal of Chemistry 43, no. 43 (2019): 16801–5. http://dx.doi.org/10.1039/c9nj04679h.

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Ba<sup>++</sup> templated Cannizzaro reactions convert symmetrical aromatic crown ether dialdehydes of various types [dibenzo and bis(meta-phenylene)] and sizes (20–32 atom rings) to acid–alcohol functionalized crown ethers in 70–98% yields.

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13

BANERJEA, AMITAVA, RADHIKA PROSAD DATTA, ABHIJIT MOOKERJEE, and A. K. BHATTACHARYYA. "DETERMINATION OF THE GROUND-STATE GEOMETRIES OF COPPER CLUSTERS BY SIMULATED ANNEALING WITHIN AN EQUIVALENT CRYSTAL APPROACH." International Journal of Modern Physics B 17, no. 03 (2003): 273–79. http://dx.doi.org/10.1142/s0217979203015826.

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We determine the lowest energy structures of small (11–20 atoms) copper clusters. The semi-empirical Equivalent Crystal Theory (ECT) is used in conjunction with the Metropolis Monte Carlo algorithm to determine the equilibrium geometry of each cluster via simulated annealing. The optimum structures of the clusters in this size range are found to be derived from icosahedral structures. The 13-atom cluster is an icosahedron and the 19-atom is a double-icosahedron. The other sizes show structures related to these. The 11-atom clusters, however, show somewhat different structures. We propose the E

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14

Nguyen, Mai, Ngo Thi Lan, and Nguyen Thanh Tung. "Geometries, stability and dissociation behavior of AgnCo clusters (n = 1-12): A theoretical investigation." Journal of Military Science and Technology 86 (April 28, 2023): 103–9. http://dx.doi.org/10.54939/1859-1043.j.mst.86.2023.103-109.

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The geometric structure, stability, dissociation channel and magnetism of AgnCo clusters (n = 1–12) have been studied using density functional theory. The results show that the Co atom tends to choose the highest coordination position. The ground state of AgnCo clusters prefers the planar motif at small sizes (n less than 4) but favors 3D structures at larger sizes (n = 5–12). The stability of clusters is not only governed by the symmetric geometry but also strongly depends on the electronic structure and the filling rule of the electron shells. The Ag9Co cluster with 18 valence electrons full

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15

Chi, Shui Lian, Ming Chen, and Song Lin Peng. "CO Adsorption on the AunS(n=1~6) Clusters: The First-Principles Study." Advanced Materials Research 341-342 (September 2011): 42–47. http://dx.doi.org/10.4028/www.scientific.net/amr.341-342.42.

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Density functional theory (DFT) calculations are performed to investigate CO bonded on the AunS (n=1~6) bimetallic clusters. It is found that the adsorption energies of CO on the AunS(n=1~6) clusters are greater than those on the pure Au clusters of corresponding sizes. This means that doped S atom can enhance CO adsorption on the Au clusters. Furthermore, through the Mulliken population analysis, we can see that charges transfer from the Au clusters to S atom, while charges donate to the Au clusters from the CO in CO/AunS sytem.

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16

Turbiner, Alexander V., Alexei B. Kaidalov, and Juan Carlos López Vieyra. "Hydrogen Atom and One-Electron Molecular Systems in a Strong Magnetic Field: Are All of Them Alike." Collection of Czechoslovak Chemical Communications 70, no. 8 (2005): 1133–56. http://dx.doi.org/10.1135/cccc20051133.

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Easy physics-inspired approximations of the total and binding energies for the H atom and for the molecular ions H2(+)(ppe), H3(2+)(pppe), (HeH)++(αpe), He2(3+)(ααe) as well as quadrupole moment for the H atom and the equilibrium distances of the molecular ions in strong magnetic fields > 109 G are proposed. The idea of approximation is based on the assumption that the dynamics of the one-electron Coulomb system in a strong magnetic field is governed by the ratio of transverse to longitudinal sizes of the electronic cloud.

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17

Sugakov, V. I. "Peculiarities of formation of implanted atom density distribution beyond ion range." Nuclear Physics and Atomic Energy 10, no. 4 (2009): 395–402. https://doi.org/10.15407/jnpae2009.04.395.

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Modeling of diffusion processes of implanted atoms in crystal and point defects, created by irradiation, beyond ion range is fulfilled. The processes of recombination of implanted atoms with thermal vacancy play the key role. It is shown, that a region strong depleted by vacancies beyond the ion range arises. In the end of this region a spike of the probabilities of the recombination processes and also the spike of density of complexes of the vacancies with implanted atoms appear. The sizes of the region rise with increasing density of the flux of implanted ions and the number of defects in cr

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18

Villagomez-Bernabe, Balder, José Ramos-Méndez, and Frederick J. Currell. "On the Equivalence of the Biological Effect Induced by Irradiation of Clusters of Heavy Atom Nanoparticles and Homogeneous Heavy Atom-Water Mixtures." Cancers 13, no. 9 (2021): 2034. http://dx.doi.org/10.3390/cancers13092034.

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A multiscale local effect model (LEM)-based framework was implemented to study the cell damage caused by the irradiation of clusters of gold nanoparticles (GNPs) under clinically relevant conditions. The results were compared with those obtained by a homogeneous mixture of water and gold (MixNP) irradiated under similar conditions. To that end, Monte Carlo simulations were performed for the irradiation of GNP clusters of different sizes and MixNPs with a 6 MV Linac spectrum to calculate the dose enhancement factor in water. The capabilities of our framework for the prediction of cell damage tr

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19

SHUKURLU, Yusif H. "THE EFFECT OF SELENIUM ON THE SUPRAMOLECULAR STRUCTURE AND THERMAL CHARACTERISTICS OF FIBROIN BOMBYX MORI L." Periódico Tchê Química 17, no. 34 (2020): 591–98. http://dx.doi.org/10.52571/ptq.v17.n34.2020.615_p34_pgs_591_598.pdf.

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The enrichment of the molecular structure of silk fibroin by selenium atom led to an increase in the branching of fibroin macromolecule. As a result, the amorphous fraction of fibroin microfiber increases which leads to an increase in the strength characteristic of the silk thread. At the same time, this change in the supramolecular structure of fibroin involving a selenium atom has enabled us to study the two-modification mechanism for crystallizing fibroin microfibers. Based on studies on the use of temperature-gravimetric and X-ray diffraction (XRD) analysis and relative changes in the prop

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20

Añez, Rafael, and Aníbal Sierraalta. "On the Electronic Effect of V, Fe, and Ni on MgO(100) and BaO(100) Surface: An Explanation from a Periodic Density Functional." Journal of Chemistry 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/6918294.

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A periodic density functional study of the V, Fe, and Ni sublayer doped MgO(100) and BaO(100) surfaces was carried out using a periodic approach in the context of the GGA approximation. Results suggest that doping atoms accommodate better in the MgO than in BaO because covalent radii of the doping atoms are closer to that of the Mg atom. Sizes of the doping atom, bulk forces, and electronic effects play an important role in the structural changes observed in doped surfaces studied herein. From all the doped studies, Ni doped Ba(100) surface is shown to be a promising material for trapping mole

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21

Valtera, Stanislav, Juraj Jašík, Mykhailo Vaidulych, et al. "Atom by atom built subnanometer copper cluster catalyst for the highly selective oxidative dehydrogenation of cyclohexene." Journal of Chemical Physics 156, no. 11 (2022): 114302. http://dx.doi.org/10.1063/5.0065350.

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The effect of particle size and support on the catalytic performance of supported subnanometer copper clusters was investigated in the oxidative dehydrogenation of cyclohexene. From among the investigated seven size-selected subnanometer copper particles between a single atom and clusters containing 2–7 atoms, the highest activity was observed for the titania-supported copper tetramer with 100% selectivity toward benzene production and being about an order of magnitude more active than not only all the other investigated cluster sizes on the same support but also the same tetramer on the other

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22

Zhang, Dong-Bo, Xing-Ju Zhao, Gotthard Seifert, Kinfai Tse, and Junyi Zhu. "Twist-driven separation of p-type and n-type dopants in single-crystalline nanowires." National Science Review 6, no. 3 (2019): 532–39. http://dx.doi.org/10.1093/nsr/nwz014.

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The distribution of dopants significantly influences the properties of semiconductors, yet effective modulation and separation of p-type and n-type dopants in homogeneous materials remain challenging, especially for nanostructures. Employing a bond orbital model with supportive atomistic simulations, we show that axial twisting can substantially modulate the radial distribution of dopants in Si nanowires (NWs) such that dopants of smaller sizes than the host atom prefer atomic sites near the NW core, while dopants of larger sizes are prone to staying adjacent to the NW surface. We attribute su

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23

Singh, Sandeep Kumar, and Avinash Parashar. "Shock resistance capability of multi-principal elemental alloys as a function of lattice distortion and grain size." Journal of Applied Physics 132, no. 9 (2022): 095903. http://dx.doi.org/10.1063/5.0106637.

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This article aims to study the shock resistance capability of multi-element alloys. In this study, we utilized nonequilibrium molecular dynamics-based simulations with an embedded atom method potential to predict the deformation governing mechanism in a multi-elemental alloy system subjected to shock loading. The evolution of shock front width, longitudinal stress, shear stress, and dislocation density were investigated for different polycrystalline multi-element systems containing different mean grain sizes of 5, 10, and 18 nm, respectively. In order to quantify the effect of lattice distorti

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TANAKA, H., T. MIZUNO, J. HIROKAWA, S. NONOSE, and T. KONDOW. "COLLISIONAL PROCESSES INVOLVING SIZE-SELECTED SODIUM-CLUSTER IONS." Surface Review and Letters 03, no. 01 (1996): 679–82. http://dx.doi.org/10.1142/s0218625x96001224.

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Collision-induced reactions of [Formula: see text](n=2–9) with Ne and Kr were investigated by means of a Tandem mass spectrometer equipped with octapole ion guide. The dominant processes were evaporation of a Na atom from [Formula: see text] with even sizes or Na 2 molecules from those with odd sizes. The absolute cross section for the reaction was measured as functions of the parent-cluster size and the collision energy. The branching fractions of the daughter-ion production were also determined. These results are interpreted in a scheme of a pair interaction in jellium background.

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Miller, Michael K., David T. Hoelzer, and Kaye F. Russell. "Towards Radiation Tolerant Nanostructured Ferritic Alloys." Materials Science Forum 654-656 (June 2010): 23–28. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.23.

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The high temperature and irradiation response of a new class of nanostructured ferritic alloys have been investigated by atom probe tomography. These materials are candidate materials for use in the extreme environments that will be present in the next generation of power generating systems. Atom probe tomography has revealed that the yttria powder is forced into solid solution during the mechanical alloying process andsubsequently 2-nm-diameter Ti-, Y- and O-enriched nanoclusters are formedduring the extrusion process. These nanoclusters have been shown to be remarkably stable during isotherm

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26

SU, YANWEI, YAN WANG, GUANGJU CHEN, and THANH N. TRUONG. "SLIDE AND ROLLING MECHANISMS OF Pt CLUSTERS OUT OF OXYGEN VACANCY REGION ON MgO(100) SURFACE." Journal of Theoretical and Computational Chemistry 08, no. 06 (2009): 1155–69. http://dx.doi.org/10.1142/s0219633609005428.

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We present the theoretical DFT/B3LYP investigations on the cluster nucleation process and moving mechanism for the Pt n (n = 1, 2, 3, 4, 8, and 12) clusters deposited on MgO surface with an embedded cluster model. The structures and energies of the Pt n clusters adsorbed on the perfect and oxygen vacancy MgO surfaces have been calculated. Based on the nucleation of the Pt n clusters on the oxygen vacancy sites of MgO surfaces, the two moving mechanisms of slide and rolling out of the vacancy region have been energetically investigated. The results show that the needed energies per atom moving

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27

Orekhov, M. A. "Coordination Numbers of Bivalent Ions in Organic Solvents." Russian Journal of Physical Chemistry A 95, no. 10 (2021): 2059–64. http://dx.doi.org/10.1134/s0036024421100204.

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Abstract Molecular dynamic models are created for properties of bivalent ions in organic solvents. It is shown that molecules of the considered solvents bound to ions via oxygen atoms. A theoretical model is developed that describes the ion coordination number. The coordination number in this model is determined by the ratio between the sizes of the ion and the atom organic molecule bound to it. It is shown that the coordination number depends weakly on the solvent and strongly on the type of ion. A value of 0.13 nm is obtained for the effective size of an oxygen atom bound to a bivalent ion.

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Rankin, Rees, and Tamara Lozano. "Adsorption Energy Shifts for Oxygen and Hydroxyl on 4-atom Metal-Decorated Graphene Catalysts Via Solvation, pH, and Substrate Dopants: Effects on ORR Activity." Metals 9, no. 2 (2019): 227. http://dx.doi.org/10.3390/met9020227.

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Recent literature results have highlighted the role of small transition metal and intermetallic nanoparticles supported on graphene as catalysts for many key applications in energy and commodity chemicals industries. Specifically, metal nanoparticle catalysts down to sizes of 4 and even 1 (single atom catalysts) on graphene have been studied for the Oxygen Reduction Reaction (ORR). A recent study showed that 4-atom transition metal intermetallic nanoparticles (NP) on graphene (metal-decorated graphene (MDG)) even generate a predictive Volcano Plot for ORR activity. Initial results from that st

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29

Baniya, Debendra. "The Hydrogen Passivated Graphene Cluster and its Stability - First Principle DFT (B3LYP) Levels of Approximation with the Basis Set 3-21G." Kathford Journal of Engineering and Management 1, no. 1 (2018): 5–10. http://dx.doi.org/10.3126/kjem.v1i1.22013.

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First-principles DFT (B3LYP) levels of calculations with the basis set 3-21G have been carried out in order to study the geometric stability and electronic properties of hydrogen passivated graphene (H-graphene) clusters(CN) (where N = 6, 10, 13, 16, 22, 24, 27, 30, 35, 37, 40, 42, 45, 47, 48, 50, 52, 54, 70 and 96) and perform the DOS spectrum on H-graphene (C16H10, C24H12, C30H14, C48H18, C70H22 and C96H24) using Mulliken population analysis by the Gaussian 03 W set of programs. The variations of ground state energy of graphene clusters are observed on sizes and corresponding number of carbo

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Cunningham, Ethan M., Thomas Taxer, Jakob Heller, Milan Ončák, Christian van der Linde, and Martin K. Beyer. "Asymmetric Solvation of the Zinc Dimer Cation Revealed by Infrared Multiple Photon Dissociation Spectroscopy of Zn2+(H2O)n (n = 1–20)." International Journal of Molecular Sciences 22, no. 11 (2021): 6026. http://dx.doi.org/10.3390/ijms22116026.

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Investigating metal-ion solvation—in particular, the fundamental binding interactions—enhances the understanding of many processes, including hydrogen production via catalysis at metal centers and metal corrosion. Infrared spectra of the hydrated zinc dimer (Zn2+(H2O)n; n = 1–20) were measured in the O–H stretching region, using infrared multiple photon dissociation (IRMPD) spectroscopy. These spectra were then compared with those calculated by using density functional theory. For all cluster sizes, calculated structures adopting asymmetric solvation to one Zn atom in the dimer were found to l

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BÖYÜKATA, MUSTAFA. "MOLECULAR DYNAMICS STUDY OF Tin, Vn AND Crn CLUSTERS." Journal of Theoretical and Computational Chemistry 06, no. 01 (2007): 81–97. http://dx.doi.org/10.1142/s0219633607002873.

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Using a Morse type pair potential, molecular-dynamics simulations have been performed to investigate the atomic geometries, growing patterns, structural stabilities, energetics and magic sizes of Ti n, V n and Cr n (n = 2-50) clusters. Following rearrangement collision of the atom–cluster system in fusion process, and absorbing their energies step by step down to 0 K, possible optimal equilibrium geometries of the clusters have been generated to tackle the structural determination problem. This approach serves an efficient alternative to the growing path identification and the optimization tec

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32

Volodin, V. N., Yu Zh Tuleushev, S. A. Trebukhov, A. V. Nitsenko, and N. M. Burabaeva. "Binary niobium alloying with low-melting metals by precipitation of nanoparticles." Izvestiya Vuzov. Tsvetnaya Metallurgiya (Universities' Proceedings Non-Ferrous Metallurgy), no. 5 (October 25, 2019): 40–48. http://dx.doi.org/10.17073/0021-3438-2019-5-40-48.

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Binary niobium alloys with tin, lead and cadmium were obtained by precipitation of nanosized metal particles dispersed in lowpressure plasma using the thermal fluctuation melting effect. The thermal fluctuation melting effect implies that a small particle is in the quasi-liquid state up to a certain critical size which, if exceeded due to steam condensation or fusion (coalescence) of other quasiliquid particles, results in the drop crystallization. The critical sizes of particles being in the quasi-liquid state and capable of coalescing and forming an alloy – solid solution – were found: Nb –

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Lu, Xuanming, Kazuyoshi Kanamori, and Kazuki Nakanishi. "Hierarchically porous monoliths based on low-valence transition metal (Cu, Co, Mn) oxides: gelation and phase separation." National Science Review 7, no. 11 (2020): 1656–66. http://dx.doi.org/10.1093/nsr/nwaa103.

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Abstract Hierarchically porous monoliths based on copper (Cu), cobalt (Co) and manganese (Mn) oxides with three-dimensionally (3D) interconnected macropores and open nanopores were prepared using metal bromides as precursors via a sol–gel process accompanied by phase separation. The difficulty of gelation for low-valence metal cation was overcome by introducing a highly electronegative Br atom near to the metal atom to control the rates of hydrolysis and polycondensation. The 3D interconnected macropores were obtained using appropriate polymers to induce phase separation. The domain sizes of m

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34

Laksono, A. K. A., and M. Munandar. "Making micro particles from bamboo." BIS Energy and Engineering 1 (November 10, 2024): V124035. https://doi.org/10.31603/biseeng.68.

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Micro-particles have sizes ranging from 1 to 1000 μm. This research reveals the role of environmentally friendly bamboo micro-particles as biomaterials with engineered material characteristics. The study indicates that bamboo, when meshed to 300 and processed with a blender machine, results in micro-cracks on the bamboo surface. SEM morphology testing, bamboo under one year old and over one year old exhibits micro-particle shapes such as imperfect circles, elongated forms, and clumps. The micro-cracks lead to the breakage of covalent bonds in cellulose. The breakage of bonds is caused by photo

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Sozykin, Sergey Anatolevich, Valeriy Petrovich Beskachko, and G. P. Vyatkin. "Calculation of Adsorption Parameters for Lithium on Carbon Nanotube (7,7) with a Double Vacancy." Materials Science Forum 843 (February 2016): 132–38. http://dx.doi.org/10.4028/www.scientific.net/msf.843.132.

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The adsorption of lithium atoms on carbon nanotubes with double vacancy structural defects (2V-defect) is being studied with first-principle modeling. The structure of defective tubes in ground state is considered, the role of effects related to finite sizes of a model is evaluated. It is demonstrated that the location of a carbon 8-ring formed by 2V-defect above the center is the most preferable for a lithium atom.

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Schumacher, Ernst, Fritz Blatter, Martin Frey, et al. "Metal Clusters: Between Atom and Bulk." CHIMIA 42, no. 11 (1988): 357. https://doi.org/10.2533/chimia.1988.357.

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The basic question of metal cluster research is the following: How do the macroscopic metallic properties – conductivity, optical lustre, chemical and catalytical reactivity, magnetism, malleability and ductility – evolve as a function of cluster size starting from the electronic states of the atom? It turns out that in a cluster of 20-40 atoms most of what we acknowledge as «metallic» is already fully developed.This is the reason why the beautiful chemistry of metal cluster complexes has not contributed to an understanding of the transitionfrom the atom to the bulk: The chemical interaction o

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Verovka, О. S., and А. О. Kolodiazhna. "Koshland’s model as a method for the analysis of enzymatic deracemization reactions." Reports of the National Academy of Sciences of Ukraine, no. 1 (February 2021): 84–92. http://dx.doi.org/10.15407/dopovidi2021.01.084.

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Koshland’s four-point location model is applied to consider some enzymatic reactions of deracemization. The sequen-tial model is a theory describing the cooperativity of protein subunits. It postulates that the conformation of the protein changes with each binding of a ligand, thus sequentially changing its affinity to ligands at adjacent binding sites. When the substrate binds to the active site of one subunit of the enzyme, the remaining subunits are activated. The possibility of the alternative binding of both substrates and products of the enzymatic reaction can be assessed on the basis of

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Bigi, A., G. Falini, E. Foresti, M. Gazzano, A. Ripmonti, and N. Roveri. "Rietveld structure refinements of calcium hydroxylapatite containing magnesium." Acta Crystallographica Section B Structural Science 52, no. 1 (1996): 87–92. http://dx.doi.org/10.1107/s0108768195008615.

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The crystal structures of four hydroxylapatite (HA) samples prepared from solutions in the presence of 10, 15, 25 and 30 Mg-atom-% have been investigated by X-ray powder pattern fitting. The total magnesium content of the solid samples, as determined by chemical analysis, was 4.9, 14.1, 20.4 and 30.6 Mg-atom-%, respectively. Rietveld analysis was performed using the computer program PREFIN implemented with routines which allow the refinements of the average crystallite sizes. Different refinement procedures were carried out in order to evaluate the effect of the amorphous and background profil

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Pang, Xiao-Feng. "The nonlinear behaviors of movement of electron in the atoms." Modern Physics Letters B 29, no. 12 (2015): 1550054. http://dx.doi.org/10.1142/s0217984915500542.

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In view of difficulties and questions of quantum mechanics in description of motion of electrons in hydrogen atom, we here established their nonlinear theory of motion based on the true motions of electron and nucleon and the real interactions between them, in which the motion of electron is depicted by a nonlinear Schrödinger equation with a Coulomb potential, the nonlinear interaction b∣φ∣2φ is produced by the change of Coulomb interaction between nucleon and electron due to the motion of nucleon. Thus the natures of the electron are thoroughly changed relative to those in quantum mechanics

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Taran, Songul, Ali Kemal Garip, and Haydar Arslan. "Theoretical study of the structures and chemical ordering of CoPd nanoalloys supported on MgO(001)." International Journal of Modern Physics C 27, no. 12 (2016): 1650146. http://dx.doi.org/10.1142/s0129183116501461.

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Metal nanoalloys on oxide surface are a widely studied topic in surface science and technology. In this study, the structures of CoPd nanoalloys adsorbed on MgO(001) have been searched by basin-hopping global optimization method within an atomistic model. Two different sizes (34 and 38 atom) have been considered for all compositions of CoPd/MgO(001) nanoalloys. Co and Pd atoms, for all the compositions, have cube-on-cube (001) epitaxy with substrate at interface. For both sizes, we have found that Pd rich composition nanoalloys have three layers, Co rich composition nanoalloys have four layers

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El-Taher, Sabry. "Theoretical investigation of the oxidation pathways of HO•-initiated reactions of acrolein, methacrolein, and trans-crotonaldehyde." Canadian Journal of Chemistry 87, no. 12 (2009): 1716–26. http://dx.doi.org/10.1139/v09-142.

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Ab initio molecular-orbital calculations have been performed to investigate the reaction mechanisms of the HO•-initiated reactions of the α,β-unsaturated aldehydes: acrolein (ACR), methacrolein (MACR), and trans-crotonaldehyde (CROT). All geometries were fully optimized at the MP2(Full)/6–31G(d,p) level. The correlation energy corrections were introduced by carrying out single-point calculations using both spin-projected second-order Møller–Plesset perturbation theory (PMP2) and coupled-cluster theory (CCSD(T)) using basis sets of different sizes. All reaction pathways studied proceed via a ba

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Prajapati, Nikunjkumar, Andrew P. Rotunno, Samuel Berweger, et al. "TV and video game streaming with a quantum receiver: A study on a Rydberg atom-based receiver's bandwidth and reception clarity." AVS Quantum Science 4, no. 3 (2022): 035001. http://dx.doi.org/10.1116/5.0098057.

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We demonstrate the ability to receive live color analog television and video game signals with the use of the Rydberg atom receiver. The typical signal expected for traditional 480i National Television Standards Committee format video signals requires a bandwidth of over 3 MHz. We determine the beam sizes, powers, and detection method required for the Rydberg atoms to receive this type of signal. The beam size affects the average time the atoms remain in the interaction volume, which is inversely proportional to the bandwidth of the receiver. We find that small beam diameters (less than 100 μm

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Walls, Michael G., Changqian Cao, Kui Yu-Zhang, Jinhua Li, Renchao Che, and Yongxin Pan. "Identification of Ferrous-Ferric Fe3O4 Nanoparticles in Recombinant Human Ferritin Cages." Microscopy and Microanalysis 19, no. 4 (2013): 835–41. http://dx.doi.org/10.1017/s1431927613001724.

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AbstractRecombinant ferritin is an excellent template for the synthesis of magnetic nanoparticles. This paper describes carefully performed experiments both to identify ironoxides within nanoparticles and to measure the number of iron atoms in the cores of recombinant human H-chain ferritin (HFn), based on spectroscopy techniques. Using electron energy-loss spectroscopy (EELS) analysis, magnetite (Fe3O4) has been unequivocally identified as the ironoxide formed within HFn cores under special preparation conditions. Atom counting analysis by EELS and high-angle annular dark-field imaging furthe

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Ungerer, Marietjie J., and Nora H. de Leeuw. "A DFT Study of Ruthenium fcc Nano-Dots: Size-Dependent Induced Magnetic Moments." Nanomaterials 13, no. 6 (2023): 1118. http://dx.doi.org/10.3390/nano13061118.

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Many areas of electronics, engineering and manufacturing rely on ferromagnetic materials, including iron, nickel and cobalt. Very few other materials have an innate magnetic moment rather than induced magnetic properties, which are more common. However, in a previous study of ruthenium nanoparticles, the smallest nano-dots showed significant magnetic moments. Furthermore, ruthenium nanoparticles with a face-centred cubic (fcc) packing structure exhibit high catalytic activity towards several reactions and such catalysts are of special interest for the electrocatalytic production of hydrogen. P

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Chen, Xiang Lei, Wei Feng Guo, Huai Jiang Du, Hui Min Weng, and Bang Jiao Ye. "The Calculation of Positron Lifetime in Ni₃Al Alloy." Materials Science Forum 607 (November 2008): 146–48. http://dx.doi.org/10.4028/www.scientific.net/msf.607.146.

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Superposed-neutral-atom model and the finite-difference method (SNA-FD) are used to calculate the positron lifetime of different sizes and types of vacancy clusters in Ni3Al alloy. The calculated positron bulk lifetime in Ni3Al agrees well with the experimental results mentioned in literatures. The positron lifetimes of vacancy clusters with the same amount of vacancy but different components are also calculated. The results show that the positron lifetime is different when its components are different. The positron lifetimes of vacancy clusters with a single element but different sizes are al

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de Obaldía, Elida I., Jesus J. Alcantar-Peña, Frederick P. Wittel, et al. "Study of Atomic Hydrogen Concentration in Grain Boundaries of Polycrystalline Diamond Thin Films." Applied Sciences 11, no. 9 (2021): 3990. http://dx.doi.org/10.3390/app11093990.

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This paper describes research focused on investigating the effect of hydrogen (H) atom insertion into the grain boundaries of polycrystalline diamond (PCD) films. This is required in order to understand the key morphological, chemical, physical, and electronic properties of the films. The PCD films were grown using the hot filament chemical vapor deposition (HFCVD) process, with flowing Ar gas mixed with CH4 and H2 gases to control film growth into microcrystalline diamond (MCD, 0.5–3 µm grain sizes), nanocrystalline diamond (NCD, 10–500 nm grain sizes), and ultrananocrystalline diamond (UNCD,

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Williamson, Christina, Agnieszka Kupc, James Wilson, et al. "Fast time response measurements of particle size distributions in the 3–60 nm size range with the nucleation mode aerosol size spectrometer." Atmospheric Measurement Techniques 11, no. 6 (2018): 3491–509. http://dx.doi.org/10.5194/amt-11-3491-2018.

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Abstract. Earth's radiation budget is affected by new particle formation (NPF) and the growth of these nanometre-scale particles to larger sizes where they can directly scatter light or act as cloud condensation nuclei (CCN). Large uncertainties remain in the magnitude and spatiotemporal distribution of nucleation (less than 10 nm diameter) and Aitken (10–60 nm diameter) mode particles. Acquiring size-distribution measurements of these particles over large regions of the free troposphere is most easily accomplished with research aircraft. We report on the design and performance of an airborne

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Heng, Tan, Wang Ze, Tan Wen-sheng, Li Xiao-ping, Qiu Jian-guo, and Yang Xiao-Hong. "Synthesis of magnetic Fe3O4 micro/nanospheres in organic solvent." Journal of Applied Biomaterials & Functional Materials 16, no. 1_suppl (2018): 26–31. http://dx.doi.org/10.1177/2280800017753328.

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Introduction: Micro/nanostructured materials have attracted a great deal of attention, and many strategies have been developed to fabricate micro/nanostructured materials. Methods: Amine-functionalized micro/nanostructured Fe3O4 with different sizes was synthesized conveniently in organic media. The chemical structures of as-synthesized products were characterized by FTIR, TEM, SEM, and XRD. Results: The ligand binds to the Fe3O4 core by hydrogen bond between the oxygen atom on the surface of Fe3O4 and the hydrogen atom in molecular ethylenediamine. Their magnetic properties were also investig

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McGreevy, Ryan, Abhishek Singharoy, Qufei Li, et al. "xMDFF: molecular dynamics flexible fitting of low-resolution X-ray structures." Acta Crystallographica Section D Biological Crystallography 70, no. 9 (2014): 2344–55. http://dx.doi.org/10.1107/s1399004714013856.

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X-ray crystallography remains the most dominant method for solving atomic structures. However, for relatively large systems, the availability of only medium-to-low-resolution diffraction data often limits the determination of all-atom details. A new molecular dynamics flexible fitting (MDFF)-based approach, xMDFF, for determining structures from such low-resolution crystallographic data is reported. xMDFF employs a real-space refinement scheme that flexibly fits atomic models into an iteratively updating electron-density map. It addresses significant large-scale deformations of the initial mod

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Kimble, Michele L., Albert W. Castleman, Jose U. Reveles, and Shiv N. Khanna. "On the Magic Character of Al6Au-." Collection of Czechoslovak Chemical Communications 72, no. 2 (2007): 185–96. http://dx.doi.org/10.1135/cccc20070185.

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Joint experimental and theoretical studies have been carried out to identify the stability of aluminum gold clusters. The experimental studies where the AlnAu- clusters are generated via laser vaporization in a flow reactor and subsequently reacted with oxygen indicate that Al6Au- is an exceptionally stable species that is not only resistant to etching by oxygen but also grows in intensity when AlnAu- clusters are exposed to oxygen. Theoretical studies indicate that the six aluminum atoms in Al6Au- form an octahedron and that the Au atom occupies a hollow site above the triangular face of the

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