Raman distributed temperature sensor can be used as temperature instruments as well as monitoring abnormalities in next-generation nuclear systems. Since noise reduction and Measuring Frequency enhancement are required, integration time adjustment has been mainly used so far. In this study, a new data processing method using Moving Average Filter was analyzed to see if noise reduction and Measuring Frequency could be reduced, and improvement measures were suggested.

There is an ever growing interest in the development of biochar from a large variety of agrowastes. Herein, the main objective is the conversion of pomegranate peel powder biochar and its post-functionalization by phosphoric acid treatment, followed by arylation organic reaction. The latter was conducted using in situ-generated diazonium salts of 4-aminobenzoic acid ( H2N-C6H4-COOH), sulfanilic acid ( H2N-C6H4-SO3H) and Azure A dye. The effect of diazonium nature and concentration on the arylation process was monitored using thermal gravimetric analysis (TGA) and Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). SEM pictures showed micrometer-sized biochar particles with tubular structure having about 10–20 μm-wide channels. SEM studies have shown that arylation did not affect the morphology upon arylation. The porous structure did not collapse and withstood the arylation organic reaction in acid medium did not collapse upon arylation. TGA and Raman indicated gradual changes in the arylation of biochar at initial concentrations 10– 5, 10– 4 and 10– 3 mol L− 1 of 4-aminobenzoic acid. The detailed Raman spectra peak fittings indicate that the D/G peak intensity ratio leveled off at 3.35 for 4-aminobenzoic acid initial concentration of 10– 4 mol L− 1, and no more change was observed, even at higher aryl group mass loading. This is in line with formation of oligoaryl grafts rather than the grafting of new aryl groups directly to the biochar surface. Interestingly, Azure A diazonium salt induced much lower extent of surface modification, likely due to steric hindrance. To the very best of our knowledge, this is the first report on diazonium modification of agrowaste-derived biochar and opens new avenues for arylated biochar and its applications.

Lately, Raman spectroscopy has become powerful tool for quality assessment of graphene analogues with identification of intensity ratio of Raman active D-band and G-band ( ID/IG ratio) as a vital parameter for quantification of defects. However, during chemical reduction of graphitic oxide (GrO) to reduced GrO (RGrO), the increased ID/ IG ratio is often wrongly recognized as defect augmentation, with “formation of more numerous yet smaller size sp2 domains” as its explanation. Herein, by giving due attention to normalized peak height, full-width half-maxima and integrated peak area of Raman D- and G-bands, and compliment the findings by XRD data, we have shown that in-plane size of sp2 domains actually increases upon chemical reduction. Particularly, contrary to increased ID/ IG ratio, the calculated decrease in integrated peak area ratio ( AD/AG ratio) in conjunction with narrowing of D-band and broadening of G-band, evinced the decrease in in-plane defects. Finally, as duly supported by reduction induced broadening of interlayer-spacing characteristic XRD peak and narrowing of ~ 43° centered XRD hump, we have also shown that the sp2 domains actually expands in size and the observed increase in ID/ IG ratio is indeed due to increase in across-plane defects, formed via along-the-layer slicing of graphitic domains.

The phenomena of single-layer graphene resonant photoluminescence and Raman radiation are discussed taking into account the photo-generated electron–hole Coulomb interaction. On the base of general principles of a many-particle interactions and the interband resonance optical transitions a photon radiation new mechanism (Coulomb mechanism) is proposed. Through Stokes 2D’-mode particular case analysis has shown that the graphene photoluminescence and the resonant Raman radiation are characterized by the same frequency shifts. Probabilities of resonance photo-radiation processes have been presented where the electron–hole Coulomb attraction has been taken into account. The probabilities are the same fourth-order small values. The weak photo-radiation Coulomb mechanism has a common character. It is applicable to both zero and nonzero band gap crystals.

This paper presents a Raman spectroscopy study of the influence of methane flow on the micro-tribological behavior of diamond-like carbon coatings deposited with an industrial plasma-enhanced chemical vapor deposition system. Results have shown a direct relationship between the methane flow and thickness of the coatings. The analysis of the Raman spectra and deposition parameters allowed establishing the influence of H content with the methane flow, the disorder level and estimation of the sp3 fraction on the carbon coatings. The micro-tribology tests showed a strong dependence of the wear resistance and hardness with Raman parameters. The coating deposited at 72-sccm methane flow presented a thickness of 1.7 μm and a sp3 fraction of 0.33. This sp3 fraction gave rise to a hardness of 24 GPa and an excellent wear resistance of 3.3 × 10–6 mm3 N−1 mm−1 for this DLC coating. Wear tests showed a swelling in the wear profiles on this coating, which was associated with the occurrence of a re-hybridization process.

Emission features formed through Raman scattering with atomic hydrogen provide unique and crucial information to probe the distribution and kinematics of a thick neutral region illuminated by a strong far-ultraviolet radiation source. We introduce a new 3-dimensional Monte-Carlo code in order to describe the radiative transfer of line photons that are subject to Raman and Rayleigh scattering with atomic hydrogen. In our Sejong Radiative Transfer through Raman and Rayleigh Scattering (STaRS) code, the position, direction, wavelength, and polarization of each photon is traced until escape. The thick neutral scattering region is divided into multiple cells with each cell being characterized by its velocity and density, which ensures exibility of the code in analyzing Raman-scattered features formed in a neutral region with complicated kinematics and density distribution. To test the code, we revisit the formation of Balmer wings through Raman scattering of the far-UV continuum near Lyβ and Lyγ in a static neutral region. An additional check is made to investigate Raman scattering of Ovi in an expanding neutral medium. We find a good agreement of our results with previous works, demonstrating the capability of dealing with radiative transfer modeling that can be applied to spectropolarimetric imaging observations of various objects including symbiotic stars, young planetary nebulae, and active galactic nuclei.

Raman Spectroscopy is a non-destructive analysis method without complex pre-processing and it can reduce the costs and time. A surface-enhanced Raman scattering (SERS) technique was tried to the detection of Benzo[a]pyrene which is one of the hazardous minor components of foods. To demonstrate the Raman signal enhancement effect by graphene as substrate, thymine was used as the standard material. As a result, the Raman signal of thymine has 102 enhancement. Herein, new SERS trials established to pursue improve the speed, simplicity and suitability of detecting minor components in foods.