micro-Raman Spectrometer Research Articles

Quantitative visualization of photosynthetic pigments in tea leaves based on Raman spectroscopy and calibration model transfer

BackgroundPhotosynthetic pigments participating in the absorption, transformation and transfer of light energy play a very important role in plant growth. While, the spatial distribution of foliar pigments is an important indicator of environmental stress, such as pests, diseases and heavy metal stress.ResultsIn this paper, in situ quantitative visualization of chlorophyll and carotenoid was realized by combining the Raman spectroscopy with calibration model transfer, and a laboratory Raman spectral model was successfully extended to a portable field spectral measurement. Firstly, a nondestructive and fast model for determination of chlorophyll and carotenoid in tea leaf was established based on confocal micro-Raman spectrometer in the laboratory. Then the spectral model was extended to a real-time foliar map scanning spectra of a field portable Raman spectrometer through calibration model transfer, and the spectral variation between the confocal micro-Raman spectrometer in the laboratory and the portable Raman spectrometer were effectively corrected by the direct standardization (DS) algorithm. The portable map scanning Raman spectra of the tea leaves after the model transfer were got into the established quantitative determination model to predict the concentration of photosynthetic pigments at each pixel of the tea leaves. The predicted photosynthetic pigments concentration of each pixel was imaged to illustrate the distribution map of foliar pigments. Statistical analysis showed that the predicted pigment contents were highly correlated with the real contents.ConclusionsIt can be concluded that the Raman spectroscopy was applicable for in situ, non-destructive and rapid quantitative detecting and imaging of photosynthetic pigment concentration in tea leaves, and the spectral detection model established based on the laboratory Raman spectrometer can be applied to a portable field spectrometer for quantitatively imaging of the foliar pigments.

Portable Raman Spectrometer for In Situ Analysis of Asbestos and Fibrous Minerals

Asbestos inhalation is associated with fatal respiratory diseases and raises concerns from the perspective of workplace safety and environmental impacts. Asbestos and asbestos-like minerals naturally occur in rocks and may become airborne when outcrops or soils are disturbed by anthropic activities. In situ detection of these minerals is a crucial step for the risk evaluation of natural sites. We assess here whether a portable Raman spectrometer (pRS) may be used in the identification of asbestos and asbestos-like minerals at the mining front during exploitation. pRS performance was tested at three geologically different mining sites in Italy and New Caledonia and compared with a high-resolution micro-Raman spectrometer (HRS). About 80% of the overall in situ analyses at the mining front were successfully identified by pRS, even when intermixed phases or strongly disaggregated and altered samples were analyzed. Chrysotile and tremolite asbestos, asbestos-like antigorite, and balangeroite were correctly detected during surveys. The major difficulties faced during in situ pRS measurements were fluorescence emission and focussing the laser beam on non-cohesive bundles of fibers. pRS is adequate for discriminating asbestos and asbestos-like minerals in situ. pRS may support risk assessment of mining sites to better protect workers and environment.

Amorphous NaVOPO 4 as a High-Rate and Ultrastable Cathode Material for Sodium-Ion Batteries

The low cost and profusion of sodium resources make sodium-ion batteries (SIBs) a potential alternative to lithium-ion batteries for grid-scale energy storage applications. However, the use of conv...

Understanding of the lubrication mechanism of reduced graphene oxide coating via dual in-situ monitoring of the chemical and topographic structural evolution

Reduced graphene oxide (rGO) has received significant attention as a potential solid lubricant material owing to its superior mechanical and tribological properties. It is considered to be a self-lubricating derivative of graphite because of its low interlayer shear stress. To further understand rGO as a lubricant material, it is necessary to clarify its evolution on the wear track during the sliding process. In this work, a dual in-situ analysis was performed via a tribo-tester instrumented with three-dimensional (3D) laser microscopy and micro-Raman spectrometer. This novel method was employed to investigate the evolutions of tribological, topographical and microstructural characteristics of the rGO coating during the sliding process. The evolution process on the wear track was demonstrated in real time via Raman spectroscopy and 3D confocal profiler. The tribological properties of the rGO coating were affected by the morphology and microstructure of the rGO on the wear track. In addition, the failure mechanism of the rGO coating was attributed to the processes of formation, removal and re-deposition of rGO-based tribofilm. Furthermore, it was determined that variation of morphology and chemical structure of wear track were synchronous in certain sliding stages.

The effect of silver nanoparticles on the penetration properties of the skin and quantification of their permeation through skin barrier

Transdermal delivery of drugs represents a non-invasive alternative treatment used not only for skin diseases. As one of the possible penetration enhancing agents, various types of nanoparticles (NPs) could be used. Silver NPs (AgNPs) could be used for some medical purposes considering their antibacterial and antiinflammatory properties. We demonstrate a novel method of quantification of permeated AgNPs, detection of AgNPs dissolving while passing the skin, and examination of interactions between skin and systems with AgNPs. Several AgNPs (exhibiting defined mean diameters of 20, 40, 60, and 100 nm) were added individually to the pure solvents commonly used in pharmaceuticals, namely ethanol, methanol, dimethyl sulfoxide, and demineralized water. AgNP dispersions in different solvents were applied to untreated samples of the skin. Attenuated total reflection technique was used for monitoring the kinetic series of infrared spectra to elucidate the time-dependent changes in the uppermost layer of the skin. The depth profiling spectra series were measured using confocal Raman microspectrometer. All recorded vibrational spectra were evaluated by multivariate statistical methods. A strong influence of AgNP size on the structural changes of the skin surface was evident. The largest changes of the skin structure were caused by the 20-nm and 40-nm AgNPs. Permeation of used AgNPs was studied on vertical Franz diffusion cells with detection of permeated AgNPs by new method based on single-particle inductively coupled plasma mass spectrometry.

Effect of substrate surface texture on adhesion performance of diamond coating

Diamond coated tools are widely applied in the field of machining, however, its use is strictly limited by weak coating-substrate adhesion. As an effective method to generate functional surfaces, the technology of texture was applied in this research to try to change the distribution of interfacial stress and improve the adhesion of coating-substrate system. Micro-textures with different densities and shapes were prepared on the surface of cemented carbide (YG6) by ultraviolet nanosecond laser, and heteroepitaxial growth of diamond coating on textured surface was realized by hot filament chemical vapor deposition (HFCVD) technology. By means of Rockwell indentation tests, micro-Raman spectrometer and thermo-solid coupling simulation analysis, the effect of textures on the adhesion of diamond coating was studied. Results indicate that the adhesion of coating-substrate increases with the increase of the micro-textures density. The normal compressive stress of diamond coating at the edges of texture inhibits the propagation of interfacial cracks, resulting in the deviation of the crack propagation path.

Effect of curing-light attenuation on color stability and physical and chemical properties of resin cements containing different photoinitiators

This study aimed to evaluate the effect of light attenuation by ceramic veneers on the degree of conversion (DC), flexural strength (FS) and color change (CC) of resin cements containing different photoinitiators. Thus, samples included resin cements containing different photoinitiators: (a) camphorquinone (CQ)/ethyl 4-(dimethylamino)benzoate (EDMAB); (b) CQ/4-(N,N-dimethylamino) phenethyl alcohol (DMPOH); (c) CQ/2(dimethylamino) ethyl methacrylate (DMAEMA); (d) CQ/ethyl 4-(dimethylamino)benzoate (EDMAB) + diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (TPO); (e) TPO; and (f) phenylbis(2.4.6-trimethylbenzoyl)phosphine oxide (BAPO). Ceramic veneers (10 × 10 mm) were 0.4 mm, 0.7 mm, 1.0 mm or 1.5 mm thick. The light irradiance of a multiple-peak LED through ceramic veneers was measured (n = 5) using a spectrometer. DC (micro-Raman spectrometer) and FS (Bar-shaped specimens) were tested in cements with and without the veneers. Color change was evaluated before and after UV artificial aging. Data were submitted to ANOVA and Tukey's test (α = 0.05). The violet spectrum showed the lowest irradiance values through the veneer, considering all thicknesses. BAPO had the highest DC values for all veneers. CQ/EDMAB + TPO, CQ + EDMAB, and CQ + DMPOH showed similar DC values concerning all thicknesses. TPO (1.0 mm) showed the lowest DC and FS values. CQ + TPO and CQ/amines showed similar FS values. CQ + EDMAB and CQ + DMAEMA showed the highest color change values while TPO showed the lowest. It was concluded that the physical and chemical properties of the resin cement were improved with BAPO. CQ/EDMAB + TPO showed the greatest color stability, considering all veneer groups and control, without affecting the other properties assessed.

Physicochemical characterization of building and painting materials from the Ptolemaic Osirian catacombs of Karnak temples, Upper Egypt

This study reports the first analytical study conducted on samples of fired bricks, bedding mortar and plaster layers collected from the catacombs of Ptolemy IV Philopator at Karnak temples, Upper Egypt. These unique constructions comprise three-level rectangular vaulted brick shrines that lined up in three passages. The microscopic particularities of the samples were assessed by digitalized optical handheld microscope, while the petrographic analysis was depicted by polarized light microscope. X-ray diffractometer was used to analyse some brick, mortar and plaster samples. The morphological description and microchemical analysis, on various points in the samples, were attained via the field-emission scanning electron microscope with an energy-dispersive X-ray spectrometer. Further, the molecular and vibrational attributions of some fragments and pigment grains were recognized using Fourier transform infrared spectrometer and Raman microspectrometer (µ-Raman). Results showed that the studied bricks were fired at low temperature using poor-calcium clays. The cross-sectional observation on the plaster layers defined three layers, which are mainly made up of calcium carbonate (calcite). Minerals of quartz, rutile, plagioclase feldspars and calcium silicate were identified, in varying proportions, in the studied plasters. Pigments as Egyptian blue, yellow ochre and red ochre were characterized along the plaster layers. Likely, the microscopic examination and the molecular analysis of the samples disclosed that “fresco” technique was used to decorate the catacombs.

A new internally heated diamond anvil cell system for time-resolved optical and x-ray measurements

We have developed a new internally heated diamond anvil cell (DAC) system for in situ high-pressure and high-temperature x-ray and optical experiments. We have adopted a self-heating W/Re gasket design allowing for both sample confinement and heating. This solution has been seldom used in the past but proved to be very efficient to reduce the size of the heating spot near the sample region, improving heating and cooling rates as compared to other resistive heating strategies. The system has been widely tested under high-temperature conditions by performing several thermal emission measurements. A robust relationship between electric power and average sample temperature inside the DAC has been established up to about 1500 K by a measurement campaign on different simple substances. A micro-Raman spectrometer was used for various in situ optical measurements and allowed us to map the temperature distribution of the sample. The distribution resulted to be uniform within the typical uncertainty of these measurements (5% at 1000 K). The high-temperature performances of the DAC were also verified in a series of XAS (x-ray absorption spectroscopy) experiments using both nano-polycrystalline and single-crystal diamond anvils. XAS measurements of germanium at 3.5 GPa were obtained in the 300 K-1300 K range, studying the melting transition and nucleation to the crystal phase. The achievable heating and cooling rates of the DAC were studied exploiting a XAS dispersive setup, collecting series of near-edge XAS spectra with sub-second time resolution. An original XAS-based dynamical temperature calibration procedure was developed and used to monitor the sample and diamond temperatures during the application of constant power cycles, indicating that heating and cooling rates in the 100 K/s range can be easily achieved using this device.

The Micro-Scaled Characterization of Natural Terrestrial Ferromanganese Coatings and Their Semiconducting Properties

Different types of ferromanganese coatings were collected from the Chinese mainland to study their mineralogical characteristics and semiconducting properties. Measurements, including by optical microscope, scanning electron microscope, energy dispersive X-ray spectroscopy, micro-Raman spectrometer and transmission electron microscope, were employed to study their morphology, mineral assemblage, element abundance and distribution patterns. Soil Fe coatings are mainly composed of Al-rich hematite and clays. Soil Fe/Mn coatings can be divided into an outer belt rich in birnessite and an inner belt rich in hematite, goethite, ilmenite and magnetite. Goethite is the only component of rock Fe coatings. Rock Fe/Mn coatings mainly consist of birnessite and hematite, and alternating Fe/Mn-rich layers and Fe/Mn-poor layers can be observed. Powders were scraped off from the topmost part of ferromanganese coatings to conduct laboratory photochemical experiments. The photocurrent–time behavior indicates that natural coating electrodes exhibit an immediate increase in photocurrent intensity when exposed to light irradiation. Natural coatings can photo-catalytically degrade 14.3%–58.4% of methyl orange in 10 h. Under light irradiation, the photocurrent enhancement and organic degradation efficiency of the rock Fe/Mn coating, which has a close intergrowth structure of Fe and Mn components, is most significant. This phenomenon is attributed to the formation of semiconductor heterojunctions, which can promote the separation of electrons and holes. Terrestrial ferromanganese coatings are common in natural settings and rich in semiconducting Fe/Mn oxide minerals. Under solar light irradiation, these coatings can catalyze important photochemical processes and will thus have an impact on the surrounding environment.

Gold Nanohelices: A New Synthesis Route, Characterization, and Plasmonic E-Field Enhancement.

Gold nanohelices (AuNHs) are synthesized using surfactant-assisted seed-mediated growth in an aqueous solution. AuNHs with diameters and lengths of 30–150 nm and several micrometers, respectively, are grown in a reaction carried out at 15 °C for 20 h by adding poly(ethylene glycol)(12)tridecyl ether, polyvinylpyrrolidone, and cetyltrimethylammonium bromide as the capping agents in an HAuCl4(aq) solution. With the addition of gold nanoparticles (AuNPs) in the reaction, the yield of the helical products is considerably increased, which indicates that AuNPs behave as the seeds for AuNH growth. The growth routes of AuNHs in the system are investigated by transmission electron microscopy measurements. Finite-difference time-domain (FDTD) simulations show that total extinction of the AuNH at 660 and 570 nm is dominantly influenced by strong e-field enhancement and the scattering of light incidence. In a practical application, surface-enhanced Raman scattering (SERS) measurements are conducted using AuNHs as the substrates and 4-mercaptobenzoic acid as the probe. A detection limit of 20 ppb is acquired using a micro-Raman spectrometer using a 633 nm He–Ne laser with a power of 3.35 mW which corresponds with the FDTD simulation results and reveals that AuNHs are superior SERS templates with resonance tuning ability in consequence of their unique helical architectures.

Identifying compositional and structural changes in the nucleus pulposus from patients with lumbar disc herniation using Raman spectroscopy.

Lower back pain (LBP) is one of the most common musculoskeletal complaints worldwide. Intervertebral disc degeneration (IDD) is considered to be a significant contributor to LBP; however, the mechanisms underlying IDD remain to be fully elucidated. One of the major features of IDD is the decreased content of type II collagen and proteoglycans in the nucleus pulposus (NP). The present study aimed to investigate the biochemical mechanisms of IDD at the microscopic level using Raman spectroscopy. Raman spectroscopy, based on inelastic scattering of light, is an emerging optical technique that may measure the chemical composition of complex biological samples, including biofluids, cells and tissues. In the present study, 30 NP tissue samples from 30 patients who were diagnosed with lumbar disc herniation and received spinal fusion surgery to relieve LBP were obtained and analyzed. Routine pre-operative 3.0T, T2-weighed MRI was used to classify the cases according to Pfirrmann grades and the T2 signal intensity value of the NP was measured. Subsequently, all NP samples were scanned and analyzed using a Laser MicroRaman Spectrometer at room temperature. The Raman spectral results demonstrated that the relative content of proteoglycans, expressed as the relative intensity ratio of two peaks (I1064/I1004), was significantly inversely correlated with the Pfirrmann grade (ρ=-0.6462; P<0.0001), whereas the content of collagen (amide I) was significantly positively correlated with the Pfirrmann grade (ρ=0.5141; P<0.01). In conclusion, the higher relative intensity of the ratio of two peaks (I1670/I1640; Amide I) represented a higher fractional content of disordered collagen, which suggested that the defective collagen structure may lead to NP abnormalities.

Investigation of Al- and N-implanted 4H–SiC applying visible and deep UV Raman scattering spectroscopy

Effects of aluminum (Al) and nitrogen (N) implantation performed at room and at elevated (500 °C) temperatures on epitaxial n-type 4H polytype silicon carbide as well as post-implantation annealing have been studied by Raman scattering spectroscopy. The amorphization of 4H–SiC is observed because of ion implantation effects. The Raman analysis showed that the recovery of the crystallinity increased with an increase in the annealing temperature. However, for samples implanted with high doses, the full crystal recovery was not complete even with annealing temperatures up to 1800 °C, and crystal defects were still present in the recrystallized layer, which was confirmed by transmission electron microscopy. Raman scattering spectra were collected at room temperature using a micro-Raman spectrometer. The visible (488 nm) and deep ultraviolet (266 nm) lasers were used as excitation sources. For the DUV laser, the optical penetration depth is less than the implanted layer thickness, and the area near the surface layer can be exactly probed. In contrast, the visible Raman spectrum shows bands characteristic of bulk 4H–SiC, which arise from the underlying non-implanted region. Based on the analysis of the longitudinal optical phonon–plasmon coupled mode, the electrical parameters for N2+ implanted samples were evaluated, where electron concentration n = 3.05 × 1018 cm−3 and mobility μ = 50 cm2/V s, respectively. The results are consistent with the parameters measured by the Hall method.

Fast screening of carotenoids of gypsum endoliths using portable Raman spectrometer (Messinian gypsum, Sicily)

AbstractWe tested the potential of a portable Raman spectrometer—RaPort (G) by EnSpectr with a 532‐nm laser for use in field detection of biomarkers of endolithic colonization in gypsum. This study extends our previous research on gypsum endolithic colonies using laboratory Raman microspectrometer (514.5‐ and 785‐nm lasers). In the current study, variously coloured layers were found and screened separately on the outcrop under natural conditions. In the recorded Raman spectra, stretching vibrations of carotenoids were observed—ν1 (C═C) around 1,513 cm−1, and ν2 (C—C) around 1,154 cm−1, as well as the feature at around 1,005 cm−1. The exact identification of different carotenoids by portable Raman spectrometer is limited. Nevertheless, the portable Raman spectrometer allowed fast and in situ detection of carotenoids of variously pigmented gypsum endolithic zones. Application of miniature Raman instruments is important in the context of forthcoming astrobiological missions to Mars (Exomars and Mars 2020).

Synthesis and characterization of magnetic nanoparticles coated with polystyrene sulfonic acid for biomedical applications

ABSTRACT The development of novel magnetic nanoparticles (MNPs) with satisfactory biocompatibility for biomedical applications has been the subject of extensive exploration over the past two decades. In this work, we synthesized superparamagnetic iron oxide MNPs coated with polystyrene sulfonic acid (PSS-MNPs) and with a conventional co-precipitation method. The core size and hydrodynamic diameter of the PSS-MNPs were determined as 8–18 nm and 50–200 nm with a transmission electron microscopy and dynamic light scattering, respectively. The saturation magnetization of the particles was measured as 60 emu g−1 with a superconducting quantum-interference-device magnetometer. The PSS content in the PSS-MNPs was 17% of the entire PSS-MNPs according to thermogravimetric analysis. Fourier-transform infrared spectra were recorded to detect the presence of SO3 − groups, which confirmed a successful PSS coating. The structural properties of the PSS-MNPs, including the crystalline lattice, composition and phases, were characterized with an X-ray powder diffractometer and 3D nanometer-scale Raman microspectrometer. MTT assay and Prussian-blue staining showed that, although PSS-MNPs caused no cytotoxicity in both NIH-3T3 mouse fibroblasts and SK-HEP1 human liver-cancer cells up to 1000 μg mL−1, SK-HEP1 cells exhibited significantly greater uptake of PSS-MNPs than NIH-3T3 cells. The low cytotoxicity and high biocompatibility of PSS-MNPs in human cancer cells demonstrated in the present work might have prospective applications for drug delivery.

Graphene oxide nano-filler based experimental dentine adhesive. A SEM / EDX, Micro-Raman and microtensile bond strength analysis.

The study aimed to assess graphene oxide (GO) adhesive and its dentin interaction using scanning electron microscopy (SEM), MicroRaman spectroscopy and Microtensile bond strength (μTBS). Experimental GOA and control adhesives (CA) were fabricated. Presence of GO within the experimental adhesive resin was assessed using SEM and Micro-Raman spectroscopy. Ninety specimens were prepared, sixty teeth were utilized for μTBS, twenty for SEM analysis of interface for CA and GOA and ten were assessed using microRaman spectroscopy. Each specimen was sectioned and exposed dentine was conditioned (35% phosphoric acid) for 10 s. The surface was coated twice with adhesive (15 s) and photopolymerized (20 s). Composite build-up on specimen was photo-polymerized. Among the bonded specimens, thirty specimen were assessed using Micro-Raman spectrometer, SEM and energy dispersive X-ray spectroscopy (EDX), whereas remaining specimens were divided in to three sub-groups (n = 10) based on the storage of 24 h, 8 weeks and 16 weeks. μTBS testing was performed at a crosshead speed of 0.5 mm/min using a microtensile tester. The means of μ-tbs were analyzed using ANOVA and post hoc Tukey multiple comparisons test. No significant difference in μTBS of CA and GOA was observed. Storage time presented a significant interaction on the μTBS (p < 0.01). The highest and lowest μTBS was evident in CA (30.47 (3.55)) at 24 h and CA (22.88 (3.61)) at 18 weeks. Micro-Raman analysis identified peaks of 1200 cm-1 to 1800 cm1, D and G bands of GO nanoparticles in the resin. Uniform distribution of graphene oxide nanoparticles was present at the adhesive and hybrid layer. GO showed interaction within adhesive and tooth dentin similar to CA, along with formation of hybrid layer. In ideal conditions (absence of nanoleakage), graphene oxide modified adhesive shows comparable bond strength and durability of resin dentine bond.

Investigating the Thermal Stress of Millisecond Pulsed Laser Irradiation on Charge-Coupled Devices

In this study, a two-dimensional model describing thermal stress on a charge-coupled device (CCD) induced by ms laser pulses was examined. Considering the nonlinearity of the CCD’s material parameters and the melting phase transition process of aluminum electrode materials was considered by using equivalent specific heat capacity method, the physical process where a laser pulse irradiating a CCD pixel array was simulated using COMSOL Multiphysics software. The temperature field and thermal stress field were calculated and analyzed. In order to clarify the mechanism producing damage on the CCD detector, Raman spectra from silicon were measured with a micro-Raman spectrometer to determine stress change in the CCD chip. The procedure presented herein illustrates a method for evaluating strain in a CCD after laser irradiation.

Effects of deep subsurface damages on surface nanostructure formation in laser recovery of grinded single-crystal silicon wafers

A nanosecond pulsed Nd:YVO4 laser was irradiated on a boron-doped single-crystal silicon wafer after rough and fine grinding processes to recover the grinding-induced subsurface damages. The surface topography of samples was investigated by using a white-light interferometer, a scanning electron microscope, and an atomic force microscope; while the crystallinity was analyzed by a laser micro-Raman spectrometer. It was found that surface nanostructures were generated by the Mullins-Sekerka instability, which remained on the surface under recoil pressure and surface tension. The rough grinding-induced deep subsurface damages influenced the interface instability between liquid and solid silicon during recrystallization process. By increasing pulse width and decreasing laser peak irradiance, the subsurface damage was recovered and a flat surface with surface roughness of ~1 nm Sa was obtained. This study reveals important correlations among grinding-induced latent subsurface defects, laser peak irradiance and nanoscale surface topography formation in laser recovery, which contributes to high quality silicon wafer manufacturing.

Use of variscite as a gemstone in the Late Bronze Age Royal Tomb at Qatna, Syria

Variscite is a green, lustrous mineral similar to turquoise. While both variscite and turquoise are aluminum-bearing, hydrated phosphate minerals, variscite contains no copper. We applied three kinds of portable analytical instruments to a nondestructive, on-site analysis of Late Bronze Age (LBA) artifacts excavated from a royal tomb at Qatna, Syria, including a portable micro-Raman spectrometer, an X-ray powder diffractometer, and an X-ray fluorescence spectrometer. Variscite was positively identified as the raw material for a number of items from the Qatna tomb. Our analytical result is the first scientific evidence of the use of variscite for personal ornaments during the LBA in the Middle East. Because differentiating between variscite and turquoise is difficult with the naked eye, it is possible that variscite artifacts were misidentified as turquoise among Middle Eastern LBA items excavated from other archaeological sites.

Relationships between structural features and reactivities of coal-chars prepared in CO2 and H2O atmospheres

Under various combustion process, CO2 and H2O both have important effects in the evolution of the structures and reactivities of chars. The purpose of this study is to investigate the characteristics of coal char after reacted under the atmospheres containing CO2 and H2O in the temperature range of 500–1000 °C. Micro-Raman and FT-IR spectrometer were used to reveal the evolution of char structural characteristic, and char reactivities were measured at isothermal condition under 70%CO2/30%O2 atmosphere on a thermogravimetric analyzer (TGA). The experimental results indicate that 700 °C was the initial temperature for additional weight loss of char which caused by H2O and CO2 gasification, and the influences of H2O gasification were obviously more drastic than that of CO2 gasification along with lower char yield under H2O containing atmospheres. It was found that more O-containing functional groups contained in the chars which prepared in CO2 and H2O atmospheres and the addition of CO2 accelerated the condensation of aromatic rings in the char, which means a more aromatic structure in char, that is, less aromatic monomers and greater condensation of them in cluster. Condensation of H2O-char and CO2/H2O-char greatly decreased at 500–700 °C and then drastically increased at 700–1000 °C. The positive correlation between the Raman parameters (I(Gr + Vr + Vl)/ID) and the char reactivity parameters (R20, R50, R80, and Rmax) was observed, which can be represented by different linear correlation model under different atmospheres.