Preparation and study of the optical properties of porous graphite

Karavanskiĭ, V. A.; Mel’nik, N. N.; Zavaritskaya, T. N.

doi:10.1134/1.1410227

Cited by 17 publications

(10 citation statements)

References 9 publications

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“…2a for the carbon band in the RS of natural molybdenite at excitation λL = 632.8 nm, we refer to the vibrational D and G(k) overlaping states. In this case, the presence of a diamond-like structure is confirmed by the observation of a fairly intense "shoulder" at 1231 cm -1 , which is absent in the nanoporous graphite Raman spectra [42], that will be discussed in more detail below. The presence of a diamond-like phase is confirmed by the presence in the spectrum in Fig.…”

Section: Discussion Of the Results Of Numerical Analysis Of The Shapementioning

confidence: 66%

“…Such shoulders are virtually absent in the RS in disordered samples of pyrolytic graphite, from the edges of graphite crystals, CHOPG or graphite whiskers, where there are only very weak T bands with frequencies of 1072 -1083 cm -1 , as well as bands 810, 867 cm -1 [37, 52 , 56, 57], which are significantly shifted in the low-frequency side of the D(k) and D(k') bands considered by us. Spectral bands or shoulders of D(k) and D(k') type are also absent in the RS of nanoporous graphite obtained by electrochemical etching of high-performance single crystals of HOPG [42].…”

Section: Discussion Of the Results Of Numerical Analysis Of The Shapementioning

confidence: 96%

“…2a, close to the component G ~ 1570 cm -1 , the line G' at 1599 cm -1 is placed, which corresponds to the maximum frequency in the phonon zone ω(k) and the maximum density of vibrational states of the graphite structure [49 -51]. The G'component is more intensive than the G line, which is similar to nanoporous graphite at a certain stage of electrochemical etching [42]. In the IR spectrum of ND annealed at 1000°C, the G'components at 1620 and 1632 cm -1 also have a high intensity, and the main component has a frequency of 1597 cm -1 [43 -45].…”

Section: Discussion Of the Results Of Numerical Analysis Of The Shapementioning

confidence: 99%

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Observation of Graphite-Like and Diamond-Like Nanostructures in the Raman Spectra of Natural and Synthesized MoS2 Crystals with Small Carbon Additives

Коrnienko

Naumenko

Kulikov

2020

Phys. Chem. Solid St.

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A comparative study of Raman spectra excited by laser radiation λL = 632.8 nm and 488 nm of natural crystals of 2H-MoS2 and nanocrystallites MoS2 (C) containing 0.5 and 1.0 wt.% Carbon additives. A detailed numerical analysis of the shape of observed D and G bands was performed. The complication of the spectra of graphite-like and diamond-like structures with the appearance of additional spectral components at 1440-1500 cm-1 and 1230-1270 cm-1 as a result of doubling the size of the corresponding elementary quasi-cells are analyzed. It is shown that the frequencies of D-bands of diamond-like nanostructures 1297 ÷ 1302 cm-1 don’t depend on λL in contrast to the change in the frequencies of the G (k)-bands. A significant effect of 632.8 nm resonant radiation on the electronic states and properties of MoS2 (C) NC was established. The strengthening of the D bands of the diamond-like structure and the ordering of the graphite structure with increasing carbon content in MoS2 (C) nanocrystals have been established. The change of spectral positions of D, G, and G (k) bands at strengthening the degree of disordering of a diamond- and graphite-like structures is considered. The influence of laser radiation on carbon structures is discussed.

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Section: Discussion Of the Results Of Numerical Analysis Of The Shapementioning

confidence: 66%

Section: Discussion Of the Results Of Numerical Analysis Of The Shapementioning

confidence: 96%

Section: Discussion Of the Results Of Numerical Analysis Of The Shapementioning

confidence: 99%

See 1 more Smart Citation

Observation of Graphite-Like and Diamond-Like Nanostructures in the Raman Spectra of Natural and Synthesized MoS2 Crystals with Small Carbon Additives

Коrnienko

Naumenko

Kulikov

2020

Phys. Chem. Solid St.

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“…Thus, the band at ~2.15 eV (575 nm) can be attributed to car bon clusters in the composite. According to the data reported in [23], the luminescence at ~570 nm is asso ciated with the presence of nanocrystals of carbon with the sp 3 bonds and its intensity correlates with an increase in the number of these bonds.…”

Section: Resultsmentioning

confidence: 86%

Luminescence induced in diamond by He+ ion implantation into SiC/C composites with an inverse opal structure

et al. 2012

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The photoluminescence induced in diamond by helium ion implantation into SiC/C nanocom posite samples and their structure revealed by high resolution transmission electron microscopy have been investigated. It has been found that, apart from crystallites of silicon carbide, graphite, and amorphous car bon, in the structure of the composites there are spherical carbon particles containing concentric graphite like shells (onion like particles). It has been established that onion like particles are formed during high tem perature treatment of SiC/C nanocomposites in the course of their preparation. It has been shown that, after the implantation with the subsequent thermal treatment, nanocomposite samples exhibit a luminescence characteristic of N-V centers in diamonds. The assumption has been made that the diamond crystallites are formed at the center of onion like particles during high temperature treatment of the composite.

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“…A similar effect has been observed during contact laser resection in the work, 29 and was explained by the presence of diamond-like microparticles that fluoresce in the same region. In the research, 30 the fluorescence of porous carbon samples was investigated. The false fluorescence signal emitted by the carbonized layer causes difficulties for the practical use of fluorescence-guided contact laser resection.…”

Section: Resultsmentioning

confidence: 99%

Can “Indirect” Contact Laser Surgery be Used for Fluorescence-Image Guided Tumor Resections? Preliminary Results

Elagin

Shakhova

Sirotkina

et al. 2018

Technol Cancer Res Treat

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Ensuring the complete removal of tumor tissue is the main challenge during resection operations. Recently, a technique of “indirect” contact laser surgery has been developed. In this study we assess the possibility of using such surgery for fluorescence image-guided tumor resection. Mouse colon adenocarcinoma CT-26 cells stably expressing the fluorescent protein mKate-2 was used as the tumor model. Resections of the tumor nodes were performed with either a scalpel blade, a laser scalpel with a bare tip, or a laser scalpel with a strongly absorbing coating on the fiber tip. Tumor-positive resection margins were detected using an IVIS Spectrum fluorescence imaging system. After tumor resection with the scalpel blade over half of the animals needed one additional resection to remove residual tumor cells. Animals in this group showed tumor recurrence within 7 days. Fluorescence imaging of the tumor bed, performed after resection to assess the presence of tumor cell clusters, was sufficiently effective only with a bloodless resection. The laser scalpels both with the bare tip and with the strongly absorbing coating on the tip provided such bloodless tumor resection in contact mode. Fewer animals required additional resections when the bare tipped scalpel was used and this also resulted in a reduction in tumor recurrence. After resections were carried out with the laser scalpel with the strongly absorbing coating on the tip, fluorescence was detected in the operative field and this led to undertaking additional resections, although subsequent investigation suggested that this was “false” fluorescence, resulting from the effects of the scalpel rather than the presence of residual tumor cells. The method of laser resection with a strongly absorbing coating on the tip therefore did not appear to demonstrate definite advantages over laser resection with a bare tip when removing tumors.

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Preparation and study of the optical properties of porous graphite

Cited by 17 publications

References 9 publications

Observation of Graphite-Like and Diamond-Like Nanostructures in the Raman Spectra of Natural and Synthesized MoS2 Crystals with Small Carbon Additives

Observation of Graphite-Like and Diamond-Like Nanostructures in the Raman Spectra of Natural and Synthesized MoS2 Crystals with Small Carbon Additives

Luminescence induced in diamond by He+ ion implantation into SiC/C composites with an inverse opal structure

Can “Indirect” Contact Laser Surgery be Used for Fluorescence-Image Guided Tumor Resections? Preliminary Results

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