Journal articles: 'Nanocluster size'

1

Ayesh, Ahmad I., Naser Qamhieh, Saleh Thaker Mahmoud, and Hussain Alawadhi. "Production of Size-Selected Cu_XSn_1-X Nanoclusters." Advanced Materials Research 295-297 (July 2011): 70–73. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.70.

Full text

Abstract:

Composites of copper–tin (CuxSn1-x) nanoclusters were synthesized using the magnetron dc sputtering gas–condensation technique. Targets with controlled ratios of Sn to Cu were used to produce CuxSn1-xwith different compositions. The effects on the nanocluster size and yield of the sputtering discharge power, inert gas flow rate, and aggregation length were investigated using a quadrupole mass filter. The sputtering discharge power was optimized to maximize the nanocluster yield. The results show that as the inert gas flow rate increases the nanocluster size increases and then decreases. These dependences could be understood in terms of the dominant nanocluster production mechanisms. This work demonstrates the ability of controlling the CuxSn1-xnanoclusters’ size and composition by optimizing the source operation conditions.

APA, Harvard, Vancouver, ISO, and other styles

2

Ott, Lisa Starkey, and Richard G. Finke. "Supersensitivity of Transition-Metal Nanoparticle Formation to Initial Precursor Concentration and Reaction Temperature: Understanding Its Origins." Journal of Nanoscience and Nanotechnology 8, no. 3 (March 1, 2008): 1551–56. http://dx.doi.org/10.1166/jnn.2008.089.

Full text

Abstract:

A supersensitivity of the formation and stabilization of transition-metal nanoclusters to the initial nanocluster concentration and temperature synthesis conditions is reported, then probed, herein for the specific case of prototype Ir(0)n nanoclusters prepared from the organometallic precursor [Bu4N]5Na3[(1,5-COD)Ir·P2W15Nb3O62] by reduction with H2 in propylene carbonate solvent. Fully isolable, redissolvable, near-monodisperse (i.e., ≤± 15% size distribution) and thus excellent Ir(0)n nanoclusters are formed using low temperature (22 °C) and moderate precursor concentration (1.2 mM) in propylene carbonate solvent. However, inferior, polydisperse (±40% size distribution), non-redispersable nanoclusters are formed at the seemingly only moderately different conditions of 38 °C higher temperature (i.e., 60 °C) and 5-fold lower precursor concentration (0.24 mM). Investigation of this supersensitivity to the nanocluster synthesis conditions reveals that it derives from the dissociation of (1,5-COD)Ir(solvent)+2 from the P2W15Nb3O9−62 polyanionic ligand/stabilizer, subsequently resulting in a too fast, kinetically uncontrolled reduction of the quickly reduced (1,5-COD)Ir(solvent)+2 as the cause of the inferior synthesis of polydisperse, non-isolable, non-redissolvable nanoclusters. The results are significant in that they illustrate that understanding the mechanism of nanocluster formation, and then performing the nanocluster synthesis under kinetically carefully controlled, understood conditions, is necessary for the formation of superior nanoclusters in this, and by implication probably many other, cases.

APA, Harvard, Vancouver, ISO, and other styles

3

Pandey, D. K., and P. S. Yadav. "Ab-Initio Study of Structural and Electronic Properties of ZnxTey (x + y = 2 to 5) Nanoclusters." Advanced Science, Engineering and Medicine 12, no. 7 (July 1, 2020): 930–38. http://dx.doi.org/10.1166/asem.2020.2634.

Full text

Abstract:

An ab initio study has been performed for the stability, structural and electronic properties of forty-four ZnxTey (x + y = p = 2 to 5) nanoclusters by employing B3LYP-DFT/LANL2DZ method. The zero-point energy correction is also considered in this study. For a particular configuration, the nanoclusters containing a large number of Te atoms are found the most stable structure in comparison with the other nanoclusters. The most stable nanoclusters have either linear or planer structures and, only Zn4Te configuration has no stable structure as the structures of this configuration have at least one imaginary vibrational frequency. The HOMO–LUMO gap of the most stable structure shows a zigzag variation with the increase in the number of atoms in the nanocluster. The observed enhancement trend of the HOMO–LUMO gap with a decrease in the size of the nanocluster confirms to the quantum-confinement effect. The ionization potential (IP) shows decreasing behavior with an increase in the number of atoms in nanoclusters and the variation of electron affinity (EA) with nanocluster size shows zig-zag behavior.

APA, Harvard, Vancouver, ISO, and other styles

4

JIA, JIN-FENG, X. LIU, S. C. LI, J. Z. WANG, J. L. LI, H. LIU, M. H. PAN, et al. "ARTIFICIAL METAL NANOCLUSTER CRYSTALS." Modern Physics Letters B 16, no. 23n24 (October 20, 2002): 889–94. http://dx.doi.org/10.1142/s0217984902004408.

Full text

Abstract:

Artificial metal nanocluster crystals, (i.e. periodic lattices consisting of identical metal nanoclusters) were fabricated using a novel technique in which surface mediated magic clustering was used to achieve identical cluster size, while the Si(111)-7 × 7 surface was used as a template for ordering the clusters. The universality of this strategy was demonstrated by fabricating more than 10 different nanocluster arrays with different metals and alloys. The atomic structures, formation mechanism and stability of the nanoclusters were studied with in situ scanning tunneling microscopy combined with first-principles total energy calculations. Our study shows that delicate control of growth kinetics is extremely important for cluster crystal fabrication.

APA, Harvard, Vancouver, ISO, and other styles

5

Yang, Rui, Daniel M. Chevrier, and Peng Zhang. "Structure and Bonding Properties of a 20-Gold-Atom Nanocluster Studied by Theoretical X-ray Absorption Spectroscopy." MRS Proceedings 1802 (2015): 33–39. http://dx.doi.org/10.1557/opl.2015.516.

Full text

Abstract:

ABSTRACTGold nanoclusters with precisely controlled atomic composition have emerged as promising materials for applications in nanotechnology because of their unique optical, electronic and catalytic properties. The recent discovery of a 20-gold-atom nanocluster protected by 16 organothiolate molecules, Au20(SR)16, is the smallest member in a surprising series of small gold−thiolate nanoclusters with a face-centered cubic (FCC) ordered core structures. A fundamental challenge facing gold nanocluster research is being able to understand the composition-dependent properties from a site-specific perspective in order to confidently establish structure-property relationships. A step in this direction is to examine the influence of various structural features (core geometry and thiolate-gold bonding motifs) on the bonding properties of gold-thiolate nanoclusters. In this work, ab initio simulations were conducted to systematically study the local structure and electronic properties of Au20(SR)16 from each unique Au and S atomic site using Au L3-edge extended X-ray absorption fine structure (EXAFS), projected density of states (l-DOS) and S K-edge X-ray absorption near edge structure (XANES) spectra. Two larger FCC-like gold-thiolate nanoclusters (Au28(SR)20 and Au36(SR)24) were used for a comparative study with Au20(SR)16, providing further predictions about the cluster size effect on the bonding properties of gold-thiolate nanoclusters with FCC-like core structures. Through this comparison, the smaller core size of Au20(SR)16 produces an EXAFS scattering signature that is non-FCC-like but shows very similar electronic properties with a larger FCC-like gold-thiolate nanocluster.

APA, Harvard, Vancouver, ISO, and other styles

6

Mondal, Shyamal, and S. R. Bhattacharyya. "Oxidation behaviour of copper nanofractals produced by soft-landing of size-selected nanoclusters." RSC Advances 5, no. 120 (2015): 99425–30. http://dx.doi.org/10.1039/c5ra20694d.

Full text

Abstract:

We report the oxidation dynamics of a copper nanocluster assembled film, containing fractal islands, fabricated by the soft-landing of size-selected copper nanoclusters with an average diameter of 3 nm.

APA, Harvard, Vancouver, ISO, and other styles

7

Cowan, Michael J., and Giannis Mpourmpakis. "Structure–property relationships on thiolate-protected gold nanoclusters." Nanoscale Advances 1, no. 1 (2019): 184–88. http://dx.doi.org/10.1039/c8na00246k.

Full text

Abstract:

Our recently developed thermodynamic stability theory was applied to a large range of ligand-protected gold nanoclusters, demonstrating its power in accurately capturing stability over large nanocluster size regimes.

APA, Harvard, Vancouver, ISO, and other styles

8

Saj, Alam, Shaikha Alketbi, Sumayya M. Ansari, Dalaver H. Anjum, Baker Mohammad, and Haila M. Aldosari. "Production of Size-Controlled Gold Nanoclusters for Vapor–Liquid–Solid Method." Nanomaterials 12, no. 5 (February 24, 2022): 763. http://dx.doi.org/10.3390/nano12050763.

Full text

Abstract:

This study demonstrated the deposition of size-controlled gold (Au) nanoclusters via direct-current magnetron sputtering and inert gas condensation techniques. The impact of different source parameters, namely, sputtering discharge power, inert gas flow rate, and aggregation length on Au nanoclusters’ size and yield was investigated. Au nanoclusters’ size and size uniformity were confirmed via transmission electron microscopy. In general, Au nanoclusters’ average diameter increased by increasing all source parameters, producing monodispersed nanoclusters of an average size range of 1.7 ± 0.1 nm to 9.1 ± 0.1 nm. Among all source parameters, inert gas flow rate exhibited a strong impact on nanoclusters’ average size, while sputtering discharge power showed great influence on Au nanoclusters’ yield. Results suggest that Au nanoclusters nucleate via a three-body collision mechanism and grow through a two-body collision mechanism, wherein the nanocluster embryos grow in size due to atomic condensation. Ultimately, the usefulness of the produced Au nanoclusters as catalysts for a vapor–liquid–solid technique was put to test to synthesize the phase change material germanium telluride nanowires.

APA, Harvard, Vancouver, ISO, and other styles

9

Ariotti, Nicholas, Hong Liang, Yufei Xu, Yueqiang Zhang, Yoshiya Yonekubo, Kerry Inder, Guangwei Du, Robert G. Parton, John F. Hancock, and Sarah J. Plowman. "Epidermal Growth Factor Receptor Activation Remodels the Plasma Membrane Lipid Environment To Induce Nanocluster Formation." Molecular and Cellular Biology 30, no. 15 (June 1, 2010): 3795–804. http://dx.doi.org/10.1128/mcb.01615-09.

Full text

Abstract:

ABSTRACT Signal transduction is regulated by the lateral segregation of proteins into nanodomains on the plasma membrane. However, the molecular mechanisms that regulate the lateral segregation of cell surface receptors, such as receptor tyrosine kinases, upon ligand binding are unresolved. Here we used high-resolution spatial mapping to investigate the plasma membrane nanoscale organization of the epidermal growth factor (EGF) receptor (EGFR). Our data demonstrate that in serum-starved cells, the EGFR exists in preformed, cholesterol-dependent, actin-independent nanoclusters. Following stimulation with EGF, the number and size of EGFR nanoclusters increase in a time-dependent manner. Our data show that the formation of EGFR nanoclusters requires receptor tyrosine kinase activity. Critically, we show for the first time that production of phosphatidic acid by phospholipase D2 (PLD2) is essential for ligand-induced EGFR nanocluster formation. In accordance with its crucial role in regulating EGFR nanocluster formation, we demonstrate that modulating PLD2 activity tunes the degree of EGFR nanocluster formation and mitogen-activated protein kinase signal output. Together, these data show that EGFR activation drives the formation of signaling domains by regulating the production of critical second-messenger lipids and modifying the local membrane lipid environment.

APA, Harvard, Vancouver, ISO, and other styles

10

Cervellino, Antonio, Cinzia Giannini, and Antonietta Guagliardi. "Determination of nanoparticle structure type, size and strain distribution from X-ray data for monatomic f.c.c.-derived non-crystallographic nanoclusters." Journal of Applied Crystallography 36, no. 5 (September 8, 2003): 1148–58. http://dx.doi.org/10.1107/s0021889803013542.

Full text

Abstract:

Whole-profile-fitting least-squares techniques are applied to simulated and experimental X-ray diffraction patterns of monatomic face-centred cubic (f.c.c.)-derived non-crystallographic nanoclusters to extract structure and size information. Three main structure types have been considered (cuboctahedral, icosahedral and decahedral). Nanocluster structure models have been generated within an original mathematical approach so as to be independent of a specific material. For each structure type, a log-normal size distribution is assumed and a phenomenological function is introduced to model possible additional size-related strain effects. The Debye function method (modified to increase computational efficiency) has been used to obtain the diffracted intensities of the nanocluster. Tests revealed the effectiveness of the method to recognize the structure types correctly and to estimate with good accuracy structure concentrations and size distributions. Application to a thiol-passivated gold nanoparticle sample is presented.

APA, Harvard, Vancouver, ISO, and other styles

11

Zhang, Zhuolei, Ji Su, Ana Sanz Matias, Madeleine Gordon, Yi-Sheng Liu, Jinghua Guo, Chengyu Song, et al. "Enhanced and stabilized hydrogen production from methanol by ultrasmall Ni nanoclusters immobilized on defect-rich h-BN nanosheets." Proceedings of the National Academy of Sciences 117, no. 47 (November 9, 2020): 29442–52. http://dx.doi.org/10.1073/pnas.2015897117.

Full text

Abstract:

Employing liquid organic hydrogen carriers (LOHCs) to transport hydrogen to where it can be utilized relies on methods of efficient chemical dehydrogenation to access this fuel. Therefore, developing effective strategies to optimize the catalytic performance of cheap transition metal-based catalysts in terms of activity and stability for dehydrogenation of LOHCs is a critical challenge. Here, we report the design and synthesis of ultrasmall nickel nanoclusters (∼1.5 nm) deposited on defect-rich boron nitride (BN) nanosheet (Ni/BN) catalysts with higher methanol dehydrogenation activity and selectivity, and greater stability than that of some other transition-metal based catalysts. The interface of the two-dimensional (2D) BN with the metal nanoparticles plays a strong role both in guiding the nucleation and growth of the catalytically active ultrasmall Ni nanoclusters, and further in stabilizing these nanoscale Ni catalysts against poisoning by interactions with the BN substrate. We provide detailed spectroscopy characterizations and density functional theory (DFT) calculations to reveal the origin of the high productivity, high selectivity, and high durability exhibited with the Ni/BN nanocatalyst and elucidate its correlation with nanocluster size and support–nanocluster interactions. This study provides insight into the role that the support material can have both regarding the size control of nanoclusters through immobilization during the nanocluster formation and also during the active catalytic process; this twofold set of insights is significant in advancing the understanding the bottom-up design of high-performance, durable catalytic systems for various catalysis needs.

APA, Harvard, Vancouver, ISO, and other styles

12

Li, Xinghe, Xinyu Qin, Bingyi Yan, Huiling Huang, Wang Zhang, and Yuanzhe Piao. "Pt Nanoclusters Anchored on Hollow Ag-Au Nanostructures for Electrochemical Oxidation of Methanol." Catalysts 10, no. 12 (December 9, 2020): 1440. http://dx.doi.org/10.3390/catal10121440.

Full text

Abstract:

The synthetic method of Pt nanocluster-anchored hollow Ag-Au nanostructures and measurements of their electrocatalytic properties for methanol oxidation reaction (MOR) are reported here. In this synthesis, uniform Ag nanospheres were prepared by reduction of silver nitrate (AgNO3) with sodium borohydride (NaBH4) and then hollow Ag-Au nanostructures were synthesized via galvanic replacement of the as-prepared Ag nanospheres with Au3+. Finally, the reduction of potassium tetrachloroplatinate (II) (K2PtCl4) with ascorbic acid was performed to deposit Pt nanoclusters on the surface of hollow Ag-Au nanostructures. The hollow interior of Pt nanocluster-anchored Ag-Au nanostructures and change in the size of Pt nanoclusters by varying the injected molar ratio of Pt/Au were observed by transmission electron microscopy (TEM). Moreover, other morphological, compositional, and optical information of the obtained nanoscale materials were analyzed by X-ray diffraction analysis (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and ultraviolet-visible spectroscopy (UV-vis). The electrocatalytic ability of the obtained Pt nanocluster-anchored hollow Ag-Au nanostructures toward MOR was confirmed by the results of cyclic voltametric (CV) measurements. The ease of three-step synthetic strategy and good electrocatalytic performance of the Pt nanocluster-anchored hollow Ag-Au nanostructures displayed their promising potential in the use of electrochemical oxidation of methanol.

APA, Harvard, Vancouver, ISO, and other styles

13

Qian, Huifeng. "Thiolate-protected Au38(SR)24 nanocluster: size-focusing synthesis, structure determination, intrinsic chirality, and beyond." Pure and Applied Chemistry 86, no. 1 (January 22, 2014): 27–37. http://dx.doi.org/10.1515/pac-2014-5011.

Full text

Abstract:

Abstract Thiolate-protected Au nanoclusters with core diameters smaller than 2 nm have captured considerable attention in recent years due to their diverse applications ranging from biological labeling to photovoltaics and catalysis. This new class of nanomaterials exhibits discrete electronic structure and molecular-like properties, such as HOMO-LUMO electronic transition, intrinsic magnetism, chiroptical properties, and enhanced catalytic properties. This review focuses on the research into thiolate-protected Au38(SR)24 – one of the most representative nanoclusters, including its identification, size-focusing synthesis, structure determination, and intrinsic chirality. The properties of two size-adjacent Au nanoclusters [Au40(SR)24 and Au36(SR)24] are also discussed. The experimental and theoretical methodologies developed in studies of the Au38(SR)24 model nanocluster open up new opportunities in the synthesis and properties investigation of other atomically precise Aun(SR)m nanoclusters.

APA, Harvard, Vancouver, ISO, and other styles

14

An, Boo Hyun, Bum Chul Park, Amarsingh Bhabu Kanagaraj, Prerna Chaturvedi, Hamad Al Yassi, Jung-Rae Park, Young Keun Kim, Jong Eun Ryu, Mihai Sanduleanu, and Daniel Sunghoi Choi. "Microwave absorption properties of magnetite multi-granule nanocluster–multiwall carbon nanotube composites." Functional Materials Letters 12, no. 02 (April 2019): 1950011. http://dx.doi.org/10.1142/s1793604719500115.

Full text

Abstract:

Fe3O4 multi-granule nanocluster–multiwall carbon nanotube composites for microwave absorbing applications are fabricated by the surface-engineered tape-casting method. The multi-granule nanoclusters are synthesized by a modified polyol hydrothermal method and characterized by transmission electron microscopy, X-ray diffraction and vibrating sample magnetometer. The complex permittivity and permeability of the composites with different granule size of nanoclusters are characterized in X-band range with the reflection method. The absorption peak of the composites are shifted from 11.1[Formula: see text]GHz to 11.51[Formula: see text]GHz as granule size increased from 18[Formula: see text]nm to 35[Formula: see text]nm.

APA, Harvard, Vancouver, ISO, and other styles

15

Liu, Kang K. L., Michael F. Hagan, and John E. Lisman. "Gradation (approx. 10 size states) of synaptic strength by quantal addition of structural modules." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1715 (March 5, 2017): 20160328. http://dx.doi.org/10.1098/rstb.2016.0328.

Full text

Abstract:

Memory storage involves activity-dependent strengthening of synaptic transmission, a process termed long-term potentiation (LTP). The late phase of LTP is thought to encode long-term memory and involves structural processes that enlarge the synapse. Hence, understanding how synapse size is graded provides fundamental information about the information storage capability of synapses. Recent work using electron microscopy (EM) to quantify synapse dimensions has suggested that synapses may structurally encode as many as 26 functionally distinct states, which correspond to a series of proportionally spaced synapse sizes. Other recent evidence using super-resolution microscopy has revealed that synapses are composed of stereotyped nanoclusters of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and scaffolding proteins; furthermore, synapse size varies linearly with the number of nanoclusters. Here we have sought to develop a model of synapse structure and growth that is consistent with both the EM and super-resolution data. We argue that synapses are composed of modules consisting of matrix material and potentially one nanocluster. LTP induction can add a trans-synaptic nanocluster to a module, thereby converting a silent module to an AMPA functional module. LTP can also add modules by a linear process, thereby producing an approximately 10-fold gradation in synapse size and strength. This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’.

APA, Harvard, Vancouver, ISO, and other styles

16

Ruffino, F., A. Canino, M. G. Grimaldi, F. Giannazzo, F. Roccaforte, and V. Raineri. "Electrical Properties of Self-Assembled Nano-Schottky Diodes." Journal of Nanomaterials 2008 (2008): 1–7. http://dx.doi.org/10.1155/2008/243792.

Full text

Abstract:

A bottom-up methodology to fabricate a nanostructured material by Au nanoclusters on 6H-SiC surface is illustrated. Furthermore, a methodology to control its structural properties by thermal-induced self-organization of the Au nanoclusters is demonstrated. To this aim, the self-organization kinetic mechanisms of Au nanoclusters on SiC surface were experimentally studied by scanning electron microscopy, atomic force microscopy, Rutherford backscattering spectrometry and theoretically modelled by a ripening process. The fabricated nanostructured materials were used to probe, by local conductive atomic force microscopy analyses, the electrical properties of nano-Schottky contact Au nanocluster/SiC. Strong efforts were dedicated to correlate the structural and electrical characteristics: the main observation was the Schottky barrier height dependence of the nano-Schottky contact on the cluster size. Such behavior was interpreted considering the physics of few electron quantum dots merged with the concepts of ballistic transport and thermoionic emission finding a satisfying agreement between the theoretical prediction and the experimental data. The fabricated Au nanocluster/SiC nanocontact is suggested as a prototype of nano-Schottky diode integrable in complex nanoelectronic circuits.

APA, Harvard, Vancouver, ISO, and other styles

17

DAI, YING, BAIBIAO HUANG, LIN YU, SHENGHAO HAN, and DADI DAI. "EFFECTS OF SURFACE OXYGEN ON THE ELECTRONIC PROPERTIES OF SILICON NANOCLUSTERS." International Journal of Nanoscience 05, no. 01 (February 2006): 13–21. http://dx.doi.org/10.1142/s0219581x06004085.

Full text

Abstract:

We have studied the effects of surface oxygen and its bond structure on the electronic properties of silicon nanoclusters by means of density functional theory calculations. The results of the energy gap as a function of the nanocluster size in hydrogen-terminated and oxygen-adsorbed silicon clusters provide a well interpretation of several experiments. The nature of electronic and optical properties of silicon nanoclusters has been discussed and attributed to the oxygen in both the Si=O double bond structure and Si–O–Si bridge structure.

APA, Harvard, Vancouver, ISO, and other styles

18

Christensen, Stephen L., Peter Cho, Amares Chatt, and Peng Zhang. "A site-specific comparative study of Au102 and Au25 nanoclusters using theoretical EXAFS and l-DOS." Canadian Journal of Chemistry 93, no. 1 (January 2015): 32–36. http://dx.doi.org/10.1139/cjc-2014-0271.

Full text

Abstract:

Recent advances in Au–thiolate nanocluster synthesis have allowed the total structural determination of several nanoclusters by X-ray crystallography. The high-precision structural information of these nanoclusters enables atomic site-specific analysis of local structure and electronic character. In this work, a site-specific comparative study of Au102(SR)44 and Au25(SR)18 was conducted to elucidate the size and site effects on the local environment and electronic character of their common surface structural unit, the –SR–Au–SR–Au–SR– “double-staple” motif. Simulation of the pseudo-radial distribution function from extended X-ray absorption fine structure (EXAFS) shows a significant difference in their local environments despite their identical geometric shape. Local density of states (l-DOS) calculations consistently reveal the difference in their electronic characters for gold d-electron density and d-DOS position. These differences are then related to the unique aurophilic interactions and size- or site-dependent electronic character of Au atoms in the double-staple motif. The differing local structure and electronic behaviour of the “double-staple” motif in Au102(SR)44 and Au25(SR)18 highlight the significance of both size and site effects on the surface structure and electronic property of Au–thiolate nanoclusters. The theoretical results may also be useful in the interpretation of future experimental XAFS and X-ray photoelectron spectroscopy (XPS) data of these nanoclusters.

APA, Harvard, Vancouver, ISO, and other styles

19

Tang, Ben Zhong, Yanhou Geng, Qunhui Sun, Xi Xiang Zhang, and Xiabin Jing. "Processible nanomaterials with high conductivity and magnetizability. Preparation and properties of maghemite/polyaniline nanocomposite films." Pure and Applied Chemistry 72, no. 1-2 (January 1, 2000): 157–62. http://dx.doi.org/10.1351/pac200072010157.

Full text

Abstract:

A versatile process employing anionic surfactants has been developed for the preparation of processible nanocomposite films with electrical conductivity and magnetic susceptibility. Maghemite (γFe2O3) nanoclusters (~10 nm in size) are coated with 4-dodecyl-benzenesulfonic acid, and polyaniline (PAn) chains are doped with 10-camphorsulfonic acid. The coated nanoclusters and doped polymers are soluble in common solvents, and casting the solutions readily gives free-standing nanocomposite films with nanocluster contents as high as ~50 wt %. The γFe2O3/PAn nanocomposites show high conductivity (82–237 S cm -1 ) and magnetizability (up to ~35 emu/g γFe2O3).

APA, Harvard, Vancouver, ISO, and other styles

20

Pandey, D. K., P. S. Yadav, S. Agrawal, and B. K. Agrawal. "Structural and Electronic Properties of ZnO NANOCLUSTERs: A B3LYP DFT Study." Advanced Materials Research 650 (January 2013): 29–33. http://dx.doi.org/10.4028/www.scientific.net/amr.650.29.

Full text

Abstract:

An ab initio B3LYP-DFT/6-311G(3df) study has been performed for the stability, structural and electronic properties of forty ZnmOn(m + n = p = 2 to 4) nanoclusters. We also consider the zero point energy correction. The nanoclusters containing large number of strongly electronegative O atoms for p = 3 and 4 are found to be most stable as compared to the other nanoclusters of the same configuration. The most stable clusters have linear or planer structures and not the three dimensional ones. The observed trend of decrease of the HOMO-LUMO gap with the size of the nanocluster is in conformity with the quantum confined behavior.

APA, Harvard, Vancouver, ISO, and other styles

21

Srivastava, Saurabh, Joseph Palathinkal Thomas, Nina Heinig, Marwa Abd-Ellah, Md Anisur Rahman, and Kam Tong Leung. "Efficient photoelectrochemical water splitting on ultrasmall defect-rich TaOx nanoclusters enhanced by size-selected Pt nanocluster promoters." Nanoscale 9, no. 38 (2017): 14395–404. http://dx.doi.org/10.1039/c7nr04378c.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Milekhin, Alexander G., Larisa L. Sveshnikova, Tatyana A. Duda, Ekaterina E. Rodyakina, Volodymyr M. Dzhagan, Ovidiu D. Gordan, Sergey L. Veber, Cameliu Himcinschi, Alexander V. Latyshev, and Dietrich R. T. Zahn. "Surface-enhanced Raman scattering by colloidal CdSe nanocrystal submonolayers fabricated by the Langmuir–Blodgett technique." Beilstein Journal of Nanotechnology 6 (December 14, 2015): 2388–95. http://dx.doi.org/10.3762/bjnano.6.245.

Full text

Abstract:

We present the results of an investigation of surface-enhanced Raman scattering (SERS) by optical phonons in colloidal CdSe nanocrystals (NCs) homogeneously deposited on both arrays of Au nanoclusters and Au dimers using the Langmuir–Blodgett technique. The coverage of the deposited NCs was less than one monolayer, as determined by transmission and scanning electron microscopy. SERS by optical phonons in CdSe nanocrystals showed a significant enhancement that depends resonantly on the Au nanocluster and dimer size, and thus on the localized surface plasmon resonance (LSPR) energy. The deposition of CdSe nanocrystals on the Au dimer nanocluster arrays enabled us to study the polarization dependence of SERS. The maximal SERS signal was observed for light polarization parallel to the dimer axis. The polarization ratio of the SERS signal parallel and perpendicular to the dimer axis was 20. The SERS signal intensity was also investigated as a function of the distance between nanoclusters in a dimer. Here the maximal SERS enhancement was observed for the minimal distance studied (about 10 nm), confirming the formation of SERS “hot spots”.

APA, Harvard, Vancouver, ISO, and other styles

23

Peleshchak, Roman, Oleh Kuzyk, and Olesya Dan'kiv. "The Conditions of Formation of the Uniform-Sized Quantum Dots in the Field of an Ultrasonic Wave." Journal of Nano Research 57 (April 2019): 40–50. http://dx.doi.org/10.4028/www.scientific.net/jnanor.57.40.

Full text

Abstract:

The non-linear diffusion-deformation theory of self-organization of nanoclusters of dot defects in semiconductor exposed to ultrasound treatment that considers the interaction of defects among themselves and with atoms of a matrix via the elastic field created by dot defects and an acoustic wave is developed. Within this theory the influence of ultrasound on the conditions of formation of spherical nanoclusters and their radius is investigated. The nanocluster size depending on average concentration of defects and amplitude of an acoustic wave is determined. It is established that ultrasonic treatment of the semiconductor in the process of formation of an ensemble of nanoclusters leads to reduction of dispersion of their sizes. In the framework of this model, a possibility of the ultrasound-stimulated the size dispersion reduction of strained InAs/GaAs quantum dots doped with an isovalent impurity are analyzed.

APA, Harvard, Vancouver, ISO, and other styles

24

Zhou, Lin, Lu Ye, and Yangcheng Lu. "Flexible and Effective Preparation of Magnetic Nanoclusters via One-Step Flow Synthesis." Nanomaterials 12, no. 3 (January 22, 2022): 350. http://dx.doi.org/10.3390/nano12030350.

Full text

Abstract:

Fe3O4 nanoclusters have attractive applications in various areas, due to their outstanding superparamagnetism. In this work, we realized a one-step flow synthesis of Fe3O4 nanoclusters, within minutes, through the sequential and quantitative introduction of reactants and modifier in a microflow system. The enhanced micromixing performance enabled a prompt and uniform supply of the modifier oleic acid (OA) for both nanoparticle modification and nanocluster stabilization to avoid uncontrolled modified nanoparticles aggregation. The size of the nanoclusters could be flexibly tailored in the range of 50–100 nm by adjusting the amount of OA, the pH, and the temperature. This rapid method proved the possibility of large-scale and stable production of magnetic nanoclusters and provided convenience for their applications in broad fields.

APA, Harvard, Vancouver, ISO, and other styles

25

Ayesh, Ahmad I. "Metal/Metal-Oxide Nanoclusters for Gas Sensor Applications." Journal of Nanomaterials 2016 (2016): 1–17. http://dx.doi.org/10.1155/2016/2359019.

Full text

Abstract:

The development of gas sensors that are based on metal/metal-oxide nanoclusters has attracted intensive research interest in the last years. Nanoclusters are suitable candidates for gas sensor applications because of their large surface-to-volume ratio that can be utilized for selective and rapid detection of various gaseous species with low-power consuming electronics. Herein, nanoclusters are used as building blocks for the construction of gas sensor where the electrical conductivity of the nanoclusters changes dramatically upon exposure to the target gas. In this review, recent progress in the fabrication of size-selected metallic nanoclusters and their utilization for gas sensor applications is presented. Special focus will be given to the enhancement of the sensing performance through the rational functionalization and utilization of different nanocluster materials.

APA, Harvard, Vancouver, ISO, and other styles

26

Turkin, A. A., M. V. Dutka, Y. T. Pei, D. I. Vainshtein, and J. Th M. De Hosson. "On the evolution of nanocluster size distribution in a nanocluster aggregation source." Journal of Applied Physics 111, no. 12 (June 15, 2012): 124326. http://dx.doi.org/10.1063/1.4731221.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Zhou, Meng, Chenjie Zeng, Qi Li, Tatsuya Higaki, and Rongchao Jin. "Gold Nanoclusters: Bridging Gold Complexes and Plasmonic Nanoparticles in Photophysical Properties." Nanomaterials 9, no. 7 (June 28, 2019): 933. http://dx.doi.org/10.3390/nano9070933.

Full text

Abstract:

Recent advances in the determination of crystal structures and studies of optical properties of gold nanoclusters in the size range from tens to hundreds of gold atoms have started to reveal the grand evolution from gold complexes to nanoclusters and further to plasmonic nanoparticles. However, a detailed comparison of their photophysical properties is still lacking. Here, we compared the excited state behaviors of gold complexes, nanolcusters, and plasmonic nanoparticles, as well as small organic molecules by choosing four typical examples including the Au10 complex, Au25 nanocluster (1 nm metal core), 13 diameter Au nanoparticles, and Rhodamine B. To compare their photophysical behaviors, we performed steady-state absorption, photoluminescence, and femtosecond transient absorption spectroscopic measurements. It was found that gold nanoclusters behave somewhat like small molecules, showing both rapid internal conversion (<1 ps) and long-lived excited state lifetime (about 100 ns). Unlike the nanocluster form in which metal–metal transitions dominate, gold complexes showed significant charge transfer between metal atoms and surface ligands. Plasmonic gold nanoparticles, on the other hand, had electrons being heated and cooled (~100 ps time scale) after photo-excitation, and the relaxation was dominated by electron–electron scattering, electron–phonon coupling, and energy dissipation. In both nanoclusters and plasmonic nanoparticles, one can observe coherent oscillations of the metal core, but with different fundamental origins. Overall, this work provides some benchmarking features for organic dye molecules, organometallic complexes, metal nanoclusters, and plasmonic nanoparticles.

APA, Harvard, Vancouver, ISO, and other styles

28

Safina, Liliya R., Karina A. Krylova, Ramil T. Murzaev, Julia A. Baimova, and Radik R. Mulyukov. "Crumpled Graphene-Storage Media for Hydrogen and Metal Nanoclusters." Materials 14, no. 9 (April 21, 2021): 2098. http://dx.doi.org/10.3390/ma14092098.

Full text

Abstract:

Understanding the structural behavior of graphene flake, which is the structural unit of bulk crumpled graphene, is of high importance, especially when it is in contact with the other types of atoms. In the present work, crumpled graphene is considered as storage media for two types of nanoclusters—nickel and hydrogen. Crumpled graphene consists of crumpled graphene flakes bonded by weak van der Waals forces and can be considered an excellent container for different atoms. Molecular dynamics simulation is used to study the behavior of the graphene flake filled with the nickel nanocluster or hydrogen molecules. The simulation results reveal that graphene flake can be considered a perfect container for metal nanocluster since graphene can easily cover it. Hydrogen molecules can be stored on graphene flake at 77 K, however, the amount of hydrogen is low. Thus, additional treatment is required to increase the amount of stored hydrogen. Remarkably, the size dependence of the structural behavior of the graphene flake filled with both nickel and hydrogen atoms is found. The size of the filling cluster should be chosen in comparison with the specific surface area of graphene flake.

APA, Harvard, Vancouver, ISO, and other styles

29

Escatllar, A. Macià, and S. T. Bromley. "Assessing the viability of silicate nanoclusters as carriers of the anomalous microwave emission: a quantum mechanical study." Astronomy & Astrophysics 634 (February 2020): A77. http://dx.doi.org/10.1051/0004-6361/201936419.

Full text

Abstract:

Nanosized silicate dust is likely to be abundant in many astronomical environments and it is a prime candidate for being the source of the anomalous microwave emission (AME). To assess the viability of silicate nanoclusters as AME carriers, their detailed properties need to be established. Using quantum chemical calculations, we compute the accurate chemical and electronic structures of three families of nanoclusters with astrophysically relevant compositions: Mg-rich olivine (Mg2SiO4)N, Mg-rich pyroxene (MgSiO3)N, and silicon monoxide (SiO)N, all in the ≤1 nm diameter size regime and for neutral and ± 1 charge states. From these fundamental data, we directly derive the shapes, ionization potentials, electron affinities, and dipole moments of all nanoclusters. The aspect ratio of the nanoclusters fluctuates significantly with N for small sizes, but especially for the olivine and pyroxene nanoclusters, it tends to stabilize towards ~1.3 for the largest sizes considered. These latter two nanocluster families tend to have mass distributions consistent with approximately prolate ellipsoidal shapes. Our calculations reveal that the dipole moment of all our nanoclusters can be substantially affected by changes in chemical structure (i.e. different isomers for a fixed N), ionisation, and substitution of Mg by Fe. Although all these factors are important, the dipole moments of our Mg-rich nanoclusters are always found to be large enough to account for the observed AME. However, (SiO)N nanoclusters are only likely to be potential AME contributors when they are both charged and their chemical structures are anisotropically segregated. We also model the emissivity per H of a representative (Mg2SiO4)3 nanocluster by directly calculating the quantum mechanical rotational energy levels and assuming a distribution of occupied levels in accordance with equilibrium Boltzmann statistics. We compare our bottom-up results with previously published classical models and show that a population of silicate nanoclusters containing only 1% of the total Si budget can reproduce the AME emissivity.

APA, Harvard, Vancouver, ISO, and other styles

30

Zhanpeisov, Nurbosyn U., and Hiroshi Fukumura. "What Silicon Nanocluster is Most Likely Formed in Etching Experiments? Theoretical DFT Study." Journal of Nanoscience and Nanotechnology 8, no. 7 (July 1, 2008): 3478–82. http://dx.doi.org/10.1166/jnn.2008.113.

Full text

Abstract:

Density functional calculations at the B3LYP/6-31G* level were performed for Si nanoclusters of ca.1 nm in size. The structural, energetic, electronic as well as the estimated absorption spectra by the time-dependent DFT (TDDFT) calculations using varied functionals and basis sets for the representative cluster models are all in favor of the formation of most probable Si35H36 nanocluster in recent electrochemical etching experiments. The nanostructure has a complete H-termination at the borderline regions and lacks from the presence of any defects like surface Si—Si dimer units formed via self-healing of dangling Si—Si bonds or from any relatively short H…H contacts.

APA, Harvard, Vancouver, ISO, and other styles

31

Anandan, B., and S. Gopalakannan. "Ex Situ Development of Y-Ti-O Nano Clusters." Applied Mechanics and Materials 787 (August 2015): 622–26. http://dx.doi.org/10.4028/www.scientific.net/amm.787.622.

Full text

Abstract:

A high density nanoscale clusters of Y–Ti–O exhibit superior creep strength and potential for high resistance to radiation damage. X-Ray Diffraction is used to determine the formation of the complex nanoclusters (NCs). The formation of Y2TiO5NCs takes place during heat treatment of mechanically milled (MM) titanium and Yttria, and also it forms the mixture of Y2Ti2O5and Y2Ti2O7NCs during the high temperature soaking of MM iron, MM titanium and yttria. The microstructure of the hot consolidated mixture of MM iron, MM titanium and yttria were obtained through scanning electron microscopy (SEM). The back scattered electron mode is used to show the contrast between different elements in the microstructure. The increase in soaking temperature increases the size of the nanocluster, which decrease the volume fraction and number densities. A large population of nanoclusters precipitates during the heat treatment at high soaking temperature.

APA, Harvard, Vancouver, ISO, and other styles

32

Lenton, Samuel, Qian Wang, Tommy Nylander, Susana Teixeira, and Carl Holt. "Structural Biology of Calcium Phosphate Nanoclusters Sequestered by Phosphoproteins." Crystals 10, no. 9 (August 27, 2020): 755. http://dx.doi.org/10.3390/cryst10090755.

Full text

Abstract:

Biofluids that contain stable calcium phosphate nanoclusters sequestered by phosphopeptides make it possible for soft and hard tissues to co-exist in the same organism with relative ease. The stability diagram of a solution of nanocluster complexes shows how the minimum concentration of phosphopeptide needed for stability increases with pH. In the stable region, amorphous calcium phosphate cannot precipitate. Nevertheless, if the solution is brought into contact with hydroxyapatite, the crystalline phase will grow at the expense of the nanocluster complexes. The physico-chemical principles governing the formation, composition, size, structure, and stability of the complexes are described. Examples are given of complexes formed by casein, osteopontin, and recombinant phosphopeptides. Application of these principles and properties to blood serum, milk, urine, and resting saliva is described to show that under physiological conditions they are in the stable region of their stability diagram and so cannot cause soft tissue calcification. Stimulated saliva, however, is in the metastable region, consistent with its role in tooth remineralization. Destabilization of biofluids, with consequential ill-effects, can occur when there is a failure of homeostasis, such as an increase in pH without a balancing increase in the concentration of sequestering phosphopeptides.

APA, Harvard, Vancouver, ISO, and other styles

33

Han, Y., A. K. Engstfeld, C. Z. Wang, L. D. Roelofs, R. J. Behm, and J. W. Evans. "Atomistic modeling of Ru nanocluster formation on graphene/Ru(0001): Thermodynamically versus kinetically directed-assembly." MRS Proceedings 1498 (2013): 249–54. http://dx.doi.org/10.1557/opl.2013.106.

Full text

Abstract:

ABSTRACTAtomistic lattice-gas models for thermodynamically and kinetically directed assembly are applied to Ru nanocluster formation on a monolayer of graphene supported on Ru(0001) at 309 K. Nanocluster density, mean size, height distribution, and spatial ordering are analyzed by kinetic Monte Carlo simulations. Both models can reproduce the experimental data, but additional density functional theory analysis favors the former.

APA, Harvard, Vancouver, ISO, and other styles

34

Hassanin, Hanaa A., and Amel Taha. "Sonochemical-Assisted Biogenic Synthesis of Theophrasite β-Ni(OH)2 Nanocluster Using Chia Seeds Extract: Characterization and Anticancer Activity." Nanomaterials 12, no. 11 (June 3, 2022): 1919. http://dx.doi.org/10.3390/nano12111919.

Full text

Abstract:

Theophrasite β-Ni(OH)2 nanocluster were fabricated via the sonochemical-assisted biogenic method using chia seeds extract as a reducing and stabilizing agent. The optical and morphological feature of the synthesized nanocluster was characterized using UV-Vis, FTIR, FE-SEM-EDS, HR-TEM, DLS, XPS, and XRD analysis. According to FE-SEM and HR-TEM images of the synthesized materials, β-Ni(OH)2 nanocluster illustrates the hexagonal particle shape with an average size of 5.8 nm, while the EDS results confirm the high purity of the synthesized nanocluster. Moreover, the XRD pattern of the synthesized materials shows typical peaks that match the reference pattern of the Theophrasite form of β-Ni(OH)2 with a hexagonal crystal system. The XPS analysis illustrates that the prepared samples exhibit both Ni2+ and Ni3+ with the predominance of Ni2+ species. Additionally the in-vitro cytotoxic activity of β-Ni(OH)2 nanocluster is tested against the MCF7 cell lines (breast cancer cells). The MTT assay results proved that the synthesized β-Ni(OH)2 nanocluster has potent cytotoxic activity against breast cancer cell lines (IC50: 62.7 μg/mL).

APA, Harvard, Vancouver, ISO, and other styles

35

Klein, Jens, Albert K. Engstfeld, Sylvain Brimaud, and R. Jürgen Behm. "Pt nanocluster size effects in the hydrogen evolution reaction: approaching the theoretical maximum activity." Physical Chemistry Chemical Physics 22, no. 34 (2020): 19059–68. http://dx.doi.org/10.1039/d0cp02793f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Jia, Jin-Feng, Jun-Zhong Wang, Xi Liu, X. S. Wang, Qi-Kun Xue, Zhi-Qiang Li, and S. B. Zhang. "Spontaneous assembly of perfectly ordered identical-size nanocluster arrays." Nanotechnology 13, no. 6 (November 15, 2002): 736–40. http://dx.doi.org/10.1088/0957-4484/13/6/308.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Kveglis, L. I., F. M. Noskov, A. A. Kalitova, R. T. Nasibullin, A. V. Nyavro, A. N. Cherepanov, A. E. Olekhnovich, and D. N. Saprykin. "Influence of the size of iron nanoclusters on their magnetization." Bulletin of the Karaganda University. "Physics" Series 106, no. 2 (June 30, 2022): 68–74. http://dx.doi.org/10.31489/2022ph2/68-74.

Full text

Abstract:

The size of iron nanocrystals significantly affects the value of their magnetization. However, an adequate model of the structure of nanocrystalline formations comprising different numbers of iron atoms still does not exist. In this work, spatial models of nanocrystalline iron clusters differing in configuration and the number of their constituent atoms are constructed. Tetrahedrally close-packed cluster assemblies of iron atoms are taken as the basis for the proposed structures of nanocrystals. The spectra of the density of electronic states for the proposed clusters are constructed using the theory of the electron density functional. The calculation was carried out by the method of scattered waves in accordance with the band theory of crystals. The appearance of magnetization in tetrahedral close-packed cluster formations is associated with excited electronic states of atoms located on the surface of the nanocluster. Excited atoms have an increased electron density, that is, electrons are able to transition to states with higher energy, approaching the Fermi energy. In this case, the Stoner criterion necessary for the occurrence of magnetization is fulfilled. The configurations of electrons with spin up and down differ, which is why uncompensated magnetic moments appear. It is shown that the proposed models of iron nanoclusters are in satisfactory agreement with the known experimental data.

APA, Harvard, Vancouver, ISO, and other styles

38

Arakelian, S. M., A. O. Kucherik, T. A. Khudaberganov, and D. N. Bukharov. "Modeling of macroscopic quantum states in functional properties of the laser-induced 4D-topological nanoclusters in thin films on solid surface." EPJ Web of Conferences 220 (2019): 01002. http://dx.doi.org/10.1051/epjconf/201922001002.

Full text

Abstract:

Nanocluster structures can be easily modified in necessary direction and by controlled way in femtonanophotonics experiments. The variation of the key topology parameters can result in new type of the quantum correlation states/size effect for charged particles. In our earlier experiments we studied laser-induced topological nanoclusters structures of different types in thin films with unique phenomena in electrophysics and optics (see [1-3]). A simple 2-steps mechanism for enhancement of quantum behavior (e.g. in electroconductivity) exists for different conditions. First, when inelastic length linelastic > acluster we have no incoherent electron-phonon (e-ph) scattering, i.e. the coherent process takes place. Second, when de Broglie wave length λdB ≡ ℓcoh < Λ, (acluster – cluster size , Λ – spatial period of nanoparticle distribution) the coherent tunneling without loss occurs, and a long-range order with interference of the states takes place in the medium due to lattice structure.

APA, Harvard, Vancouver, ISO, and other styles

39

Newcomer Provencio, P., J. E. Martin, J. G. Odinek, and J. P. Wilcoxon. "Studies of Hexagonal Pt and Au Nanocluster Superlattices." Microscopy and Microanalysis 4, S2 (July 1998): 734–35. http://dx.doi.org/10.1017/s1431927600023795.

Full text

Abstract:

We have recently synthesized superlattices of Pt and Au nanoclusters grown by inverse micelle techniques. The monodisperse nanosize metal clusters used in this study were synthesized as surfactant aggregates surrounded by an oil-like environment (inverse micelle), a technique developed and patented at Sandia. Reaction byproducts, such as excess surfactant and inorganic ion salts, are often separated from the metal clusters using liquid chromatography size exclusion techniques; however, the Pt and Au nanoclusters in this study have been fractionated using a liquid-liquid technique. The nanoclusters are capped with a ligand.Two-dimensional hexagonal arrays formed readily on surfaces, and large twinned three-dimensional crystals form from solution. Both the cluster size and the size of the capping ligand can be controlled to form superlattices having a range of lattice parameters. We have found that the capping agent exerts a marked influence on the tendency of these clusters to order.

APA, Harvard, Vancouver, ISO, and other styles

40

Sartorel, Elodie, Caner Ünlü, Mini Jose, Aurélie Massoni-Laporte, Julien Meca, Jean-Baptiste Sibarita, and Derek McCusker. "Phosphatidylserine and GTPase activation control Cdc42 nanoclustering to counter dissipative diffusion." Molecular Biology of the Cell 29, no. 11 (June 2018): 1299–310. http://dx.doi.org/10.1091/mbc.e18-01-0051.

Full text

Abstract:

The anisotropic organization of plasma membrane constituents is indicative of mechanisms that drive the membrane away from equilibrium. However, defining these mechanisms is challenging due to the short spatiotemporal scales at which diffusion operates. Here, we use high-density single protein tracking combined with photoactivation localization microscopy (sptPALM) to monitor Cdc42 in budding yeast, a system in which Cdc42 exhibits anisotropic organization. Cdc42 exhibited reduced mobility at the cell pole, where it was organized in nanoclusters. The Cdc42 nanoclusters were larger at the cell pole than those observed elsewhere in the cell. These features were exacerbated in cells expressing Cdc42-GTP, and were dependent on the scaffold Bem1, which contributed to the range of mobility and nanocluster size exhibited by Cdc42. The lipid environment, in particular phosphatidylserine levels, also played a role in regulating Cdc42 nanoclustering. These studies reveal how the mobility of a Rho GTPase is controlled to counter the depletive effects of diffusion, thus stabilizing Cdc42 on the plasma membrane and sustaining cell polarity.

APA, Harvard, Vancouver, ISO, and other styles

41

Kim, Jooyeon, Giljae Lee, and Jingyu Kim. "Magnetic Nanoclusters for T2 MR Imaging in Cancer using Xenograft Mice Model." ScholarGen Publishers 3, no. 1 (December 28, 2020): 1–7. http://dx.doi.org/10.31916/sjmi2020-01-01.

Full text

Abstract:

In this study, we tried to develop nanoprobe for molecular magnetic resonance (MR) imaging using magnetic nanoclusters (MNC). MNCs for magnetic resonance imaging were synthesized by thermal decomposition. The size of the synthesized MNC was confirmed to be 73 ± 32.4 nm. Cytotoxicity test of the synthesized MNCs showed that the cell state of about 80% or more did not change in all the treatment ranges and cell survival rate was high even though the MNCs were injected. MNC was injected intravenously into the tail vein of nude mice. As a result, it was found that enhancement of the contrast was confirmed in xenograft mice model using MNC. These results will contribute to clinical application and related research through magnetic nanocluster in the future.

APA, Harvard, Vancouver, ISO, and other styles

42

Nies, Cara-Lena, and Michael Nolan. "DFT calculations of the structure and stability of copper clusters on MoS2." Beilstein Journal of Nanotechnology 11 (February 26, 2020): 391–406. http://dx.doi.org/10.3762/bjnano.11.30.

Full text

Abstract:

Layered materials, such as MoS2, are being intensely studied due to their interesting properties and wide variety of potential applications. These materials are also interesting as supports for low-dimensional metals for catalysis, while recent work has shown increased interest in using 2D materials in the electronics industry as a Cu diffusion barrier in semiconductor device interconnects. The interaction between different metal structures and MoS2 monolayers is therefore of significant importance and first-principles simulations can probe aspects of this interaction not easily accessible to experiment. Previous theoretical studies have focused particularly on the adsorption of a range of metallic elements, including first-row transition metals, as well as Ag and Au. However, most studies have examined single-atom adsorption or adsorbed nanoparticles of noble metals. This means there is a knowledge gap in terms of thin film nucleation on 2D materials. To begin addressing this issue, we present in this paper a first-principles density functional theory (DFT) study of the adsorption of small Cu n (n = 1–4) structures on 2D MoS2 as a model system. We find on a perfect MoS2 monolayer that a single Cu atom prefers an adsorption site above the Mo atom. With increasing nanocluster size the nanocluster binds more strongly when Cu atoms adsorb atop the S atoms. Stability is driven by the number of Cu–Cu interactions and the distance between adsorption sites, with no obvious preference towards 2D or 3D structures. The introduction of a single S vacancy in the monolayer enhances the copper binding energy, although some Cu n nanoclusters are actually unstable. The effect of the vacancy is localised around the vacancy site. Finally, on both the pristine and the defective MoS2 monolayer, the density-of-states analysis shows that the adsorption of Cu introduces new electronic states as a result of partial Cu oxidation, but the metallic character of Cu nanoclusters is preserved.

APA, Harvard, Vancouver, ISO, and other styles

43

Xia, Nan, Zibao Gan, Lingwen Liao, Shengli Zhuang, and Zhikun Wu. "The reactivity of phenylethanethiolated gold nanoparticles with acetic acid." Chem. Commun. 53, no. 85 (2017): 11646–49. http://dx.doi.org/10.1039/c7cc06210a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Yoon, Ki Youl, Mohammad Mehrmohammadi, Ameya Borwankar, Stanislav Y. Emelianov, and Keith P. Johnston. "Synthesis of Iron Oxide Nanoclusters with Enhanced Magnetization and Their Applications in Pulsed Magneto-Motive Ultrasound Imaging." Nano 10, no. 05 (July 2015): 1550073. http://dx.doi.org/10.1142/s1793292015500733.

Full text

Abstract:

We report here a facile synthetic approach for preparing water-soluble Fe 3 O 4 nanoparticle (NP) clusters with tunable size distribution and magnetic properties. The primary NP sizes were controlled by tuning the nucleation and growth rates with temperature and ligand concentration while the nanocluster sizes were manipulated by controlling interparticle interactions. We have investigated the size control of clusters as well as individual primary NPs via dynamic light scattering (DLS) analysis and transmission electron microscopy (TEM). Superconducting quantum interference device (SQUID) was used to measure the magnetic properties of Fe 3 O 4 NP for determining the effect of size distribution at room temperature. These water dispersible NP clusters can be utilized in various biomedical applications. In this study, we demonstrated the application of synthesized nanoclusters to enhance imaging contrast a novel ultrasound-based imaging modality, pulsed magneto-motive ultrasound (pMMUS) imaging. Our results indicated that by using the NP clusters with enhanced magnetic properties, the pMMUS signal increased significantly which is an essential requirement for further development of in vivo pMMUS imaging.

APA, Harvard, Vancouver, ISO, and other styles

45

Yang, Jingjing, Lu Zhang, Qian Zhou, Fan Chen, Martina Stenzel, Fucheng Gao, Chao Liu, Huiqing Yuan, Hui Li, and Yanyan Jiang. "Self-assembled anionic and cationic Au nanoparticles with Au nanoclusters for the exploration of different biological responsiveness in cancer therapy." Nanoscale Advances 3, no. 10 (2021): 2812–21. http://dx.doi.org/10.1039/d0na01066a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Ma, Jie, Xindan Zhang, and Shiwu Gao. "Tunable electron and hole injection channels at plasmonic Al–TiO2 interfaces." Nanoscale 13, no. 33 (2021): 14073–80. http://dx.doi.org/10.1039/d1nr03697a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Karanjit, Sangita, Ayumu Tamura, Masaya Kashihara, Kazuki Ushiyama, Lok Kumar Shrestha, Katsuhiko Ariga, Atsushi Nakayama, and Kosuke Namba. "Hydrotalcite-Supported Ag/Pd Bimetallic Nanoclusters Catalyzed Oxidation and One-Pot Aldol Reaction in Water." Catalysts 10, no. 10 (September 29, 2020): 1120. http://dx.doi.org/10.3390/catal10101120.

Full text

Abstract:

A highly active hydrotalcite-supported Ag/Pd bimetallic nanocluster catalyst has been developed by a simple, easy and safe chemical reduction method. The catalyst was characterized by high-resolution transmission electron microscopy (HR-TEM), which revealed very small (3.2 ± 0.7 nm) nanoclusters with a narrow size distribution. The bimetallic Ag/Pd catalyst showed strong cooperation between Ag and Pd for the alcohol oxidation reaction. The developed catalyst provided an efficient and environmentally friendly method for alcohol oxidation and one-pot cross-aldol condensation in water. A broad scope of α,β-unsaturated ketones with good to excellent yields were obtained under very mild conditions. This catalytic system offers an easy preparation method with a simple recovery process, good activity and reusability of up to five cycles without significant loss in the catalytic activity.

APA, Harvard, Vancouver, ISO, and other styles

48

Srivastava, Saurabh, Joseph Palathinkal Thomas, Md Anisur Rahman, Marwa Abd-Ellah, Mamata Mohapatra, Debabrata Pradhan, Nina F. Heinig, and Kam Tong Leung. "Size-Selected TiO2 Nanocluster Catalysts for Efficient Photoelectrochemical Water Splitting." ACS Nano 8, no. 11 (November 11, 2014): 11891–98. http://dx.doi.org/10.1021/nn505705a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Xu, Xiaofan, Wei Wang, Dongliang Liu, Dandan Hu, Tao Wu, Xianhui Bu, and Pingyun Feng. "Pushing up the Size Limit of Metal Chalcogenide Supertetrahedral Nanocluster." Journal of the American Chemical Society 140, no. 3 (January 16, 2018): 888–91. http://dx.doi.org/10.1021/jacs.7b12092.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Tannenbaum, Rina, Melissa Zubris, Eugene P. Goldberg, Shimon Reich, and Nily Dan. "Polymer-Directed Nanocluster Synthesis: Control of Particle Size and Morphology." Macromolecules 38, no. 10 (May 2005): 4254–59. http://dx.doi.org/10.1021/ma048317x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Nanocluster size'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles