scholarly journals 2013–2014 Survey of Chars Using Raman Spectroscopy

2021 ◽  
Vol 7 (3) ◽  
pp. 63
Author(s):  
John McDonald-Wharry
Keyword(s):  
Heat Treatment ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Amorphous Carbon ◽  
Field Conditions ◽  
Carbon Dating ◽  
Effective Heat ◽  
Anthracite Coal ◽  
Wide Range

In late 2013, an open call for charcoal and biochar samples was distributed in an effort to compare a wide range of char samples by Raman spectroscopy. The samples contributed to this survey included: laboratory produced biochars, recent biochars produced in field conditions, and ancient char samples previously analysed by carbon dating. By using selected Raman measurements, the char samples could be ranked in terms of the degree of thermochemical alteration or extent of carbon nanostructural development. The Raman results for recently produced biomass chars were generally consistent with the conversion of amorphous carbon formed at lower temperatures into condensed, polyaromatic, and graphene-like carbon formed at higher temperatures. A number of parameters calculated from the Raman spectra could be used to estimate the effective heat treatment temperatures in the recently produced biochars. Other samples such as anthracite coal, tire pyrolysis carbon, and ancient chars departed from the trends observed in the recently produced biomass chars using this approach. In total, 45 samples were analysed by Raman spectroscopy for this survey. Ancient and buried char samples displayed higher intensities for features in the Raman spectra associated with amorphous carbon.

Searching for life in volcanic carbonate systems and the effect of temperature on organic molecules

2021 ◽  
Author(s):  
Alexander O'Donnell
Keyword(s):  
Raman Spectroscopy ◽  
Organic Matter ◽  
Raman Spectra ◽  
Elemental Carbon ◽  
Organic Molecules ◽  
Spectral Response ◽  
High Rate ◽  
Effect Of Temperature ◽  
Thermal Alteration ◽  
Wide Range

<p>Carotenoid compounds such as β-carotene are some of the most prevalent organic molecules on Earth and are key biomarkers as there is no known abiogenic source. During diagenesis and thermal alteration, carbon undergoes well-documented changes in Raman spectra.</p><p>There has been little research into the transitional degradation of carotenoid spectra to where they are fully replaced by the carbon spectra as the main identifier of thermal maturity under Raman spectroscopy. This is an overlooked regime when discussing the search for life, terrestrial and extra-terrestrial, where current research (using Raman spectroscopy) either focuses on finding living organisms displaying common organic molecules, or looks for the elemental carbon evidence of extinct fossil life. The real world is not usually so polarised, so covering the transition between these modes of life detection will improve any detection analysis.</p><p>For this study the volcanic thermal spring system in Viterbo, Italy was used as a field-based laboratory. The high rate of carbonate precipitation in these thermal springs, the wide range of thermal regimes (58°C to 25°C), and the prevalence of fast-growing algae in the run-off streams, give excellent preservation of a range of organic matter states at directly measurable temperatures.</p><p>The results demonstrate how the Raman spectra of the carotenoid compounds change with hydration, death of the organism, and thermal alteration of the organic material. The relationship between the spectra of the carotenoid compound and the elemental carbon spectra in the transition zone is also shown.</p><p>This study expands on the use of Raman spectroscopy of carbon as a low-temperature geothermometer, and provides a framework for the spectral response of organic matter in an often-overlooked geological regime. It is anticipated that the fields of geothermal energy, climatology, geobiology and astrogeobiology, could all benefit from this study, incorporating this enhanced thermal alteration data into existing and future work.</p>

scholarly journals Study of CVD diamond layers with amorphous carbon admixture by Raman scattering spectroscopy

2015 ◽  
Vol 33 (4) ◽  
pp. 799-805 ◽  
Author(s):  
Anna Dychalska ◽  
Piotr Popielarski ◽  
Wojciech Franków ◽  
Kazimierz Fabisiak ◽  
Kazimierz Paprocki ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Amorphous Carbon ◽  
Diamond Films ◽  
Standard Technique ◽  
Cvd Diamond ◽  
Chemical Vapor Deposition Method ◽  
First Order ◽  
Diamond Layer ◽  
Diamond Phase

AbstractRaman spectroscopy is a most often used standard technique for characterization of different carbon materials. In this work we present the Raman spectra of polycrystalline diamond layers of different quality, synthesized by Hot Filament Chemical Vapor Deposition method (HF CVD). We show how to use Raman spectroscopy for the analysis of the Raman bands to determine the structure of diamond films as well as the structure of amorphous carbon admixture. Raman spectroscopy has become an important technique for the analysis of CVD diamond films. The first-order diamond Raman peak at ca. 1332 cm−1 is an unambiguous evidence for the presence of diamond phase in the deposited layer. However, the existence of non-diamond carbon components in a CVD diamond layer produces several overlapping peaks in the same wavenumber region as the first order diamond peak. The intensities, wavenumber, full width at half maximum (FWHM) of these bands are dependent on quality of diamond layer which is dependent on the deposition conditions. The aim of the present work is to relate the features of diamond Raman spectra to the features of Raman spectra of non-diamond phase admixture and occurrence of other carbon structures in the obtained diamond thin films.

Characteristic Improvement of Carbon Coating by Furan Resin on Natural Graphite as Anode for Lithium Ion Batteries

2012 ◽  
Vol 581-582 ◽  
pp. 768-772
Author(s):  
Yu Shiang Wu
Keyword(s):  
Heat Treatment ◽  
Raman Spectroscopy ◽  
Lithium Ion Batteries ◽  
Amorphous Carbon ◽  
Carbon Coating ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Natural Graphite ◽  
X Ray ◽  
Furan Resin

Natural graphite and carbonaceous materials are the most promising materials as the anode for lithium ion batteries. Carbon coating on natural graphite can inhibit the insertion of lithium complex into graphite and reduce its irreversibility. This study verifies that furan resin can be used as a carbon-coating material to enhance the electrochemistry of the charging and discharging cycles. Furan resin changes into amorphous carbon after heat treatment at 1100°C. It is determined that the 40 wt.% furan resin/natural graphite combination material clearly improves the electrochemical properties by electrical cycling tests. The surface properties have been investigated by Raman spectroscopy profiles and the bulk analyzed by X-ray diffraction (XRD) measurements.

Observation of Atom Rows in Thorium Pyromellitate Using a Field Emission STEM

1977 ◽  
Vol 35 ◽  
pp. 80-81
Author(s):  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Field Emission ◽  
Amorphous Carbon ◽  
Carbon Film ◽  
Dark Field Image ◽  
Dark Field ◽  
Amorphous Carbon Film ◽  
Atomic Size ◽  
Wide Range ◽  
A Chain

It is interesting to observe polymers at atomic size resolution. Some works have been reported for thorium pyromellitate by using a STEM (1), or a CTEM (2,3). The results showed that this polymer forms a chain in which thorium atoms are arranged. However, the distance between adjacent thorium atoms varies over a wide range (0.4-1.3nm) according to the different authors.The present authors have also observed thorium pyromellitate specimens by means of a field emission STEM, described in reference 4. The specimen was prepared by placing a drop of thorium pyromellitate in 10-3 CH3OH solution onto an amorphous carbon film about 2nm thick. The dark field image is shown in Fig. 1A. Thorium atoms are clearly observed as regular atom rows having a spacing of 0.85nm. This lattice gradually deteriorated by successive observations. The image changed to granular structures, as shown in Fig. 1B, which was taken after four scanning frames.

Submicron Simultaneous IR and Raman Spectroscopy (IR+Raman): Breakthrough Developments in Optical Photothermal IR (O-PTIR) Combined for Enhanced Failure Analysis

2019 ◽  
Author(s):  
Jay Anderson ◽  
Mustafa Kansiz ◽  
Michael Lo ◽  
Curtis Marcott
Keyword(s):  
Raman Spectroscopy ◽  
Failure Analysis ◽  
Data Quality ◽  
Raman Spectra ◽  
Spatial Resolution ◽  
Far Field ◽  
Field Mode ◽  
Microscopic Scale ◽  
Analytical Tools ◽  
Ir And Raman

Abstract Failure analysis of organics at the microscopic scale is an increasingly important requirement, with traditional analytical tools such as FTIR and Raman microscopy, having significant limitations in either spatial resolution or data quality. We introduce here a new method of obtaining Infrared microspectroscopic information, at the submicron level in reflection (far-field) mode, called Optical-Photothermal Infrared (O-PTIR) spectroscopy, that can also generate simultaneous Raman spectra, from the same spot, at the same time and with the same spatial resolution. This novel combination of these two correlative techniques can be considered to be complimentary and confirmatory, in which the IR confirms the Raman result and vice-versa, to yield more accurate and therefore more confident organic unknowns analysis.

scholarly journals Quantitative and Qualitative Analysis of Some Inorganic Compounds by Raman Spectroscopy

1994 ◽  
Vol 48 (7) ◽  
pp. 875-883 ◽  
Author(s):  
Daniel R. Lombardi ◽  
Chao Wang ◽  
Bin Sun ◽  
Augustus W. Fountain ◽  
Thomas J. Vickers ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Raman Spectroscopy ◽  
Qualitative Analysis ◽  
Raman Spectra ◽  
Solid Phase ◽  
Inorganic Compounds ◽  
Core Material ◽  
Storage Tanks ◽  
Hanford Site ◽  
Sampling Probe

Raman spectra have been measured for a number of nitrates, nitrites, sulfates, ferrocyanides, and ferricyanides, both in the solid phase and in aqueous solution. Accurate locations of peak maxima are given. Limits of detection for some of the compounds are given for solutions and for solid mixtures in NaNO3. Preliminary measurements have been made on core material recovered from the storage tanks on the Hanford site in Richland, Washington. Representative spectra are presented, showing that it is possible to observe responses of individual components from measurements made directly on untreated cores, with the use of a fiberoptic sampling probe.

scholarly journals Raman Spectroscopy Investigation of Graphene Oxide Reduction by Laser Scribing

2021 ◽  
Vol 7 (2) ◽  
pp. 48
Author(s):  
Vittorio Scardaci ◽  
Giuseppe Compagnini
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Reduce Graphene Oxide ◽  
Oxide Reduction ◽  
Material Parameters ◽  
Laser Scribing ◽  
Wide Range ◽  
Scan Speed ◽  
Laser Reduction

Laser scribing has been proposed as a fast and easy tool to reduce graphene oxide (GO) for a wide range of applications. Here, we investigate laser reduction of GO under a range of processing and material parameters, such as laser scan speed, number of laser passes, and material coverage. We use Raman spectroscopy for the characterization of the obtained materials. We demonstrate that laser scan speed is the most influential parameter, as a slower scan speed yields poor GO reduction. The number of laser passes is influential where the material coverage is higher, producing a significant improvement of GO reduction on a second pass. Material coverage is the least influential parameter, as it affects GO reduction only under restricted conditions.

scholarly journals Indication of high lipid content in epithelial-mesenchymal transitions of breast tissues

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Siti Norbaini Sabtu ◽  
S. F. Abdul Sani ◽  
L. M. Looi ◽  
S. F. Chiew ◽  
Dharini Pathmanathan ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Raman Spectroscopy ◽  
Multivariate Analysis ◽  
Nucleic Acids ◽  
Raman Spectra ◽  
Cancer Progression ◽  
Component Analysis ◽  
Breast Cancer Tissue ◽  
Metabolic Changes ◽  
Cancer Tissue

AbstractThe epithelial-mesenchymal transition (EMT) is a crucial process in cancer progression and metastasis. Study of metabolic changes during the EMT process is important in seeking to understand the biochemical changes associated with cancer progression, not least in scoping for therapeutic strategies aimed at targeting EMT. Due to the potential for high sensitivity and specificity, Raman spectroscopy was used here to study the metabolic changes associated with EMT in human breast cancer tissue. For Raman spectroscopy measurements, tissue from 23 patients were collected, comprising non-lesional, EMT and non-EMT formalin-fixed and paraffin embedded breast cancer samples. Analysis was made in the fingerprint Raman spectra region (600–1800 cm−1) best associated with cancer progression biochemical changes in lipid, protein and nucleic acids. The ANOVA test followed by the Tukey’s multiple comparisons test were conducted to see if there existed differences between non-lesional, EMT and non-EMT breast tissue for Raman spectroscopy measurements. Results revealed that significant differences were evident in terms of intensity between the non-lesional and EMT samples, as well as the EMT and non-EMT samples. Multivariate analysis involving independent component analysis, Principal component analysis and non-negative least square were used to analyse the Raman spectra data. The results show significant differences between EMT and non-EMT cancers in lipid, protein, and nucleic acids. This study demonstrated the capability of Raman spectroscopy supported by multivariate analysis in analysing metabolic changes in EMT breast cancer tissue.

scholarly journals Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski
Keyword(s):  
Raman Spectroscopy ◽  
Cell Walls ◽  
Structural Changes ◽  
Spatial Information ◽  
Technological Development ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Plant Tissues ◽  
Wide Range ◽  
Identification Technique

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.

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