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Raman crystallinity

Vivian Müller, Feng Shao, Milos Baljozovic, Mina Moradi, Yao Zhang, Thomas Jung, William B Thompson, Benjamin T King, Renato Zenobi, A Dieter Schlüter
This work describes a two-dimensional polymerization at an air/water interface and provides, for the first time, direct spectroscopic evidence for the kind of cross-links formed and for the conversion reached in a covalently bonded monolayer sheet. This is achieved by a combination of a variety of monolayer characterization techniques before and after transfer onto solid substrates in particular by tip-enhanced Raman spectroscopy (TERS) and TERS mapping after transfer of both the monomer and polymer monolayer onto Au(111)...
September 18, 2017: Angewandte Chemie
Basam A E Ben-Arfa, Hugo R Fernandes, Isabel M Miranda Salvado, José M F Ferreira, Robert C Pullar
Sol-gel glasses in quaternary silica-sodium-calcium-phosphorous systems have been synthesised using a rotary evaporator for rapid drying without ageing. This novel fast drying method drastically decreases the total drying and ageing time from several weeks to only 1 hour, thus overcoming a serious drawback in sol-gel preparation procedures for bioglasses. This work investigates the bioactivity behaviour of two glasses synthesised by this fast method, with Ca:P ratios of 1.5, and 1.67. X-ray diffraction (XRD), Inductive coupled plasma (ICP), Fourier-transform infrared (FTIR) and Raman spectroscopy were used to confirm the bioactivity of the synthesised powders...
September 16, 2017: Journal of Biomedical Materials Research. Part A
Laryssa Pinheiro Costa Silva, Jairo Pinto Oliveira, Wanderson Juvencio Keijok, André Romero da Silva, Anderson Rocha Aguiar, Marco Cesar Cunegundes Guimarães, Carolina Magri Ferraz, Jackson Victor Araújo, Fernando Luiz Tobias, Fábio Ribeiro Braga
The biosynthesis of metallic nanoparticles (NPs) using biological systems such as fungi has evolved to become an important area of nanobiotechnology. Herein, we report for the first time the extracellular synthesis of highly stable silver NPs (AgNPs) using the nematophagous fungus Duddingtonia flagrans (AC001). The fungal cell-free filtrate was analyzed by the Bradford method and 3,5-dinitrosalicylic acid assay and used to synthesize the AgNPs in the presence of a 1 mM AgNO3 solution. They have been characterized by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy, dynamic light scattering, Zeta potential measurements, Fourier-transform infrared, and Raman spectroscopes...
2017: International Journal of Nanomedicine
Patrick M Wallace, Patrick E Sims, Chi Xu, Christian D Poweleit, John Kouvetakis, José Menéndez
Epitaxial synthesis of Ga(As1-xPx)Ge3 alloys on Si (100) substrates is demonstrated using Chemical Vapor Deposition reactions of [D2GaN(CH3)2]2, with P(GeH3)3 and As(GeH3)3 precursors. These compounds are chosen to promote the formation of GaAsGe3 and GaPGe3 building blocks which interlink to produce the desired crystalline product. Ge-rich (GaP)yGe5-2y analogues have also been grown with tunable Ge contents up to 90% by reactions of P(GeH3)3 with [D2GaN(CH3)2]2 under similar deposition protocols. In both cases the crystal growth utilized Ge1-xSix buffer layers whose lattice constants were specifically tuned as a function of composition to allow perfect lattice matching with the target epilayers...
September 13, 2017: ACS Applied Materials & Interfaces
Dmytro Solonenko, Ovidiu D Gordan, Guy Le Lay, Dietrich R T Zahn, Patrick Vogt
The investigation of the vibrational properties of epitaxial silicene and two-dimensional (2D) Si structures on the silver(111) surface aims for a better understanding of the structural differences and of the simplification of the seemingly complex phase diagrams reported over the last years. The spectral signatures of the main silicene phases epitaxially grown on Ag(111) were obtained using in situ Raman spectroscopy. Due to the obvious 2D nature of various epitaxial silicene structures, their fingerprints consist of similar sets of Raman modes...
2017: Beilstein Journal of Nanotechnology
Lili Qiu, Miriam Peña-Alvarez, Mercedes Taravillo, Paul J Evans, Evan Darzi, Ramesh Jasti, P Mayorga Burrezo, Juan T López Navarrete, Valentín G Baonza, Juan Casado, Miklos Kertesz
We find evidence for the surprising formation of polymeric phases under high pressure for conjugated nanohoop molecules. This paper represents one of the unique cases where the molecular-level effects of pressure in crystalline organic solids is addressed and provides a suitable general approach based on vibrational Raman spectroscopy combining experiments and computations. In particular we studied the structural and supramolecular chemistry of the cyclic conjugated nanohoop molecule, [5]cyclo-para-phenylene under high pressures of 0 to 10 GPa...
September 12, 2017: Chemistry: a European Journal
Man Kit Cheng, Jing Liang, Ying-Hoi Lai, Liang-Xi Pang, Yi Liu, Junying Shen, Jianqiang Hou, Qing Lin He, Bochao Xu, Junshu Chen, Gan Wang, Chang Liu, Rolf Lortz, Iam Keong Sou
We have developed an incandescent Mo source to fabricate large-area single-crystalline MoSe<sub>2</sub> thin films. The as-grown MoSe<sub>2</sub> thin films were characterized using transmission electron spectroscopy, energy dispersive X-ray analysis, atomic force microscopy, Raman spectroscopy, photoluminescence, reflection high energy electron diffraction (RHEED) and angular resolved photoemission spectroscopy (ARPES). A new Raman characteristic peak at 1591 cm<sup>-1</sup> was identified...
September 11, 2017: Nanotechnology
P Abinaya Sindu, Elayaraja Kolanthai, R V Suganthi, K Thanigai Arul, E Manikandan, Luiz H Catalani, S Narayana Kalkura
The aim of the current study is to synthesize nanosized silicon incorporated HAp (Si-HAP) using sodium metasilicate as the silicon source. The sol-gel derived samples were further subjected to microwave irradiation. Incorporation of Si into HAp did not alter the HAp phase, as confirmed by the X-ray diffraction analysis (XRD). Moreover, variation in the lattice parameters of the Si-incorporated HAp indicates that Si is substituted into the HAp lattice. The decrease in the intensity of the peaks attributed to hydroxyl groups, which appeared in the FTIR and Raman spectra of Si-HAp, further confirms the Si substitution in HAp lattices...
August 24, 2017: Journal of Photochemistry and Photobiology. B, Biology
F S Lopes, J R Oliveira, J Milani, L D Oliveira, J P B Machado, V J Trava-Airoldi, A O Lobo, F R Marciano
Recently, the development of coatings to protect biomedical alloys from oxidation, passivation and to reduce the ability for a bacterial biofilm to form after implantation has emerged. Diamond-like carbon films are commonly used for implanted medical due to their physical and chemical characteristics, showing good interactions with the biological environment. However, these properties can be significantly improved when titanium dioxide nanoparticles are included, especially to enhance the bactericidal properties of the films...
December 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Adel A Ismail, Ibrahim Abdelfattah, M Faisal, Ahmed Helal
The unabated release of herbicide imazapyr into the soil and groundwater led to crop destruction and several pollution-related concerns. In this contribution, heterogeneous photocatalytic technique was employed utilizing mesoporous Ga2O3-TiO2 nanocomposites for degrading imazapyr herbicide as a model pollutant molecule. Mesoporous Ga2O3-TiO2 nanocomposites with varied Ga2O3 contents (0-5wt%) were synthesized through sol-gel process. XRD and Raman spectra exhibited extremely crystalline anatase TiO2 phase at low Ga2O3 content which gradually reduced with the increase of Ga2O3 content...
August 23, 2017: Journal of Hazardous Materials
Yunxiao Zhang, Tao Cai, Wangji Shang, Dan Liu, Qiang Guo, Shenggao Liu
A novel environmentally friendly bis-functional dicationic ionic liquid containing chelated orthoborate was synthesized and polycondensed with glutamic acid in order to synthesize inorganic-organic carbon dots (CD/IL) consisting of an ionic liquid moiety inserted in the carbon skeleton. The obtained CD/IL was found to be a new kind of nitrogen/boron-codoped nanomaterial, one with a mean particle diameter of 2.66 nm. CD/IL was verified to be a high-performance lubricant additive: in particular, the anti-wear and friction-reducing properties of poly(ethylene glycol) (PEG) were improved by 89...
September 8, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
B R Coyac, B Hoac, P Chafey, G Falgayrac, L Slimani, P S Rowe, G Penel, A Linglart, M D McKee, C Chaussain, C Bardet
X-linked hypophosphatemia (XLH) is a skeletal disease caused by inactivating mutations in the PHEX gene. Mutated or absent PHEX protein/enzyme leads to a decreased serum phosphate level, which cause mineralization defects in the skeleton and teeth (osteomalacia/odontomalacia). It is not yet altogether clear whether these manifestations are caused solely by insufficient circulating phosphate availability for mineralization or also by a direct, local intrinsic effect caused by impaired PHEX activity. Here, we evaluated the local role of PHEX in a 3-dimensional model of extracellular matrix (ECM) mineralization...
September 1, 2017: Journal of Dental Research
D Sangamithirai, S Munusamy, V Narayanan, A Stephen
A study on the voltammetric detection of NADH (β-nicotinamide adenine dinucleotide), Dopamine (DA) and their simultaneous determination is presented in this work. The electrochemical sensor was fabricated with the hybrid nanocomposites of poly(o-anisidine) and silver nanoparticles prepared by simple and cost-effective insitu chemical oxidative polymerization technique. The nanocomposites were synthesized with different (w/w) ratios of o-anisidine and silver by increasing the amount of o-anisidine in each, by keeping silver at a fixed quantity...
November 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
S Kurabayashi, K Nagashio
The advantage of MoS2, compared with graphene, is the direct growth on various oxide substrates by chemical vapor deposition (CVD) without utilizing catalytic metal substrates, which facilitates practical applications for electronics. The carrier mobility is, however, degraded from the intrinsic limit mainly due to short-range scattering caused by S vacancies formed during CVD growth. If the upper limit for the crystallinity of CVD-MoS2 on oxide substrates is determined by the MoS2/substrate interaction during growth, it will hinder the advantage...
September 14, 2017: Nanoscale
Ding-Shiang Wang, Shou-Yi Chang, Tai-Sheng Chen, Tung-Huan Chou, Yi-Ching Huang, Jin-Bao Wu, Ming-Sheng Leu, Hong-Jen Lai
This study reports a mechanical stress-based technique that involves scratching or imprinting to write textured graphite conducting wires/patterns in an insulating amorphous carbon matrix for potential use as interconnects in future carbonaceous circuits. With low-energy post-annealing below the temperature that is required for the thermal graphitization of amorphous carbon, the amorphous carbon phase only in the mechanically stressed regions transforms into a well aligned crystalline graphite structure with a low electrical resistivity of 420 μΩ-cm, while the surrounding amorphous carbon matrix remains insulating...
August 29, 2017: Scientific Reports
Saswati Santra, Nirmalya Sankar Das, Nripen Besra, Diptonil Banerjee, Kalyan Kumar Chattopadhyay
CuBO2 nanostructures were synthesized employing low cost hydrothermal technique to combine into CuBO2-RGO nanocomposite for the first time using chemically prepared graphene sheets. The nanohybrid samples were characterized for structural information using X-ray diffraction (XRD) which revealed proper crystalline phase formation of CuBO2 unaltered by composite formation with graphene. Raman spectroscopic studies were employed to confirm the presence of graphene. Morphological study with field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) suggested proper wrapping of RGO sheets over CuBO2nanocubes...
August 24, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Nazek El Atab, Gamze Ulusoy Ghobadi, Amir Ghobadi, Junkyo Suh, Raisul Islam, Ali Kemal Okyay, Krishna C Saraswat, Ammar Nayfeh
The manipulation of matter at the nanoscale enables the generation of properties in a material that would otherwise be challenging or impossible to realize in the bulk state. Here, we demonstrate growth of zirconia nano-islands using Atomic Layer Deposition (ALD) on different substrate terminations. Transmission Electron Microscopy and Raman measurements indicate that the nano-islands consist of nano-crystallites of the cubic-crystalline phase, which results in a higher dielectric constant (κ~35) than the amorphous phase case (κ~20)...
August 23, 2017: Nanotechnology
Intu Sharma, B R Mehta
Integration of a layered two-dimensional (2D) material with non-2D material provides a platform where one can modulate and achieve properties desired for various next-generation electronic and opto-electronic applications. Here, we investigate ZnTe nanoparticles/MoS2 hetero-interfaces with thickness of MoS2 varying from a few to multilayers. High resolution transmission electron microscopy has been used to observe crystalline behaviour of ZnTe nanoparticles while numbers of layers of MoS2 are investigated using Raman measurements...
August 23, 2017: Nanotechnology
Vadivel Vinod Kumar, Rajamani Rajmohan, Pothiappan Vairaprakash, Mariappan Mariappan, Savarimuthu Philip Anthony
The intriguing structural properties of coordination polymers (COPs), together with the huge variety of metal ions and organic linkers to choose from, make COPs potential precursors for fabricating carbon-encapsulated metal and metal oxide nanoparticles (NPs). Herein, we have studied the role of the COP structural assembly, prepared through making subtle changes to the ligand structure, on the formation of NPs in a carbon matrix. Cu-COPs (Cu-COP-1-Cu-COP-7), generated using different amino acid-based reduced Schiff base phenolic chelating ligands, exhibited crystalline structures with differing structural organization in the solid state...
September 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Amel Slimani, Fares Nouioua, Alban Desoutter, Bernard Levallois, Frédéric J G Cuisinier, Hervé Tassery, Elodie Terrer, Hamideh Salehi
The separation zone between enamel and dentin [dentin-enamel junction (DEJ)] with different properties in biomechanical composition has an important role in preventing crack propagation from enamel to dentin. The understanding of the chemical structure (inorganic and organic components), physical properties, and chemical composition of the human DEJ could benefit biomimetic materials in dentistry. Spatial distribution of calcium phosphate crystallinity and the collagen crosslinks near DEJ were studied using confocal Raman microscopy and calculated by different methods...
August 2017: Journal of Biomedical Optics
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