Antimicrobial Tendency of Bagasse Lignin Extracts by Raman Peak Intensity

Sugar Tech ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 697-705
Author(s):  
Jackapon Sunthornvarabhas ◽  
Prapassorn Rungthaworn ◽  
Udomlak Sukatta ◽  
Narissara Juntratip ◽  
Klanarong Sriroth
Keyword(s):  
Raman Peak ◽  
Peak Intensity ◽  
Raman Peak Intensity

Study of surface defects and crystallinity of MWCNTs growth in FCCVD

2017 ◽  
Vol 24 (6) ◽  
pp. 845-851
Author(s):  
Shazia Shukrullah ◽  
Norani Muti Mohamed ◽  
Maizatul Shima Shaharun ◽  
Muhammad Yasin Naz
Keyword(s):  
Carbon Nanotubes ◽  
Surface Defects ◽  
Chemical Vapor ◽  
Raman Peak ◽  
Multiwalled Carbon ◽  
Peak Intensity ◽  
Black Spots ◽  
Pure Carbon ◽  
Structural Growth ◽  
Raman Peak Intensity

AbstractThis research investigated the structural growth of multiwalled carbon nanotubes (MWCNTs) in a double stage horizontal chemical vapor deposition (CVD) reactor. Ethylene was used as a carbon source for nucleation of nanotubes. Ferrocene catalyst weight was varied from 0.1 to 0.2 g to demonstrate the growth of MWCNTs on Si/SiO2/Al2O3 substrate. The obtained data revealed that the weight of the catalyst significantly affects the diameter, crystallinity, alignment and yield of the nanotubes. Lower inner-shell spacing and the ratio of D-Raman peak intensity and G-Raman peak intensity (ID/IG ratio) were obtained with 0.15 g of ferrocene, which was an indication of relatively pure carbon nanotubes (CNTs) growth. Raman spectra also confirmed the highly crystalline and relatively pure CNTs structures with ID/IG ratio of 0.700. TGA data revealed the formation of 97% pure nanotubes with oxidation temperature of 620°C. However, above and below the optimum (0.15 g of ferrocene), some of the grown CNTs were found defective and few black spots were also seen in TEM micrographs.

scholarly journals Analysis of Sildenafil in Liquor and Health Wine Using Surface Enhanced Raman Spectroscopy

2019 ◽  
Vol 20 (11) ◽  
pp. 2722
Author(s):  
Shupei Xiao ◽  
Yong He
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Raman Peak ◽  
Peak Intensity ◽  
Raman Enhancement ◽  
Relative Standard ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Alcoholic Drinks ◽  
Raman Peak Intensity

The illegal adulteration of sildenafil in herbal food supplements and alcoholic drinks immensely threatens human health due to its harmful side-effects. Therefore, it is important to accurately detect and identify the presence of sildenafil in alcoholic drinks. In this study, Opto Trace Raman 202 (OTR 202) was used as surface enhanced Raman spectroscopy (SERS) active colloids to detect sildenafil. The results demonstrated that the Raman enhancement factor (EF) of OTR 202 colloids reached 1.84 × 107 and the limits of detection (LODs) of sildenafil in health wine and liquor were found to be as low as 0.1 mg/L. Moreover, the SERS peaks of 645, 814, 1235, 1401, 1530 and 1584 cm−1 could be qualitatively determined as sildenafil characteristic peaks and the relationship between Raman peak intensity and sildenafil concentration in health wine and liquor were different. There was a good linear correlation between Raman peak intensity, and sildenafil concentration in health wine ranged 0.1–1 mg/L (0.9687< R2 < 0.9891) and 1–10 mg/L (0.9701 < R2 < 0.9840), and in liquor ranged 0.1–1 mg/L (0.9662 < R2 < 0.9944) and 1–20 mg/L (0.9625 < R2 < 0.9922). The relative standard deviations (RSD) were less than 5.90% (sildenafil in health wine) and 9.16% (sildenafil in liquor). The recovery ranged 88.92–104.42% (sildenafil in health wine) and 90.09–104.55% (sildenafil in liquor). In general, the sildenafil in health wine and liquor could be rapidly and quantitatively determined using SERS technique, which offered a simple and accurate alternative for the determination of sildenafil in alcoholic drinks.

DX CENTERS IN AlGaN

1999 ◽  
Vol 13 (11) ◽  
pp. 1363-1378 ◽  
Author(s):  
M. D. McCLUSKEY ◽  
C. G. VAN de WALLE ◽  
N. M. JOHNSON ◽  
D. P. BOUR ◽  
M. KNEISSL
Keyword(s):  
Deep Level ◽  
Far Infrared ◽  
Shallow Donor ◽  
Experimental Investigations ◽  
Nitride Semiconductors ◽  
Dx Centers ◽  
Free Carriers ◽  
Peak Intensity ◽  
Oxygen Impurities ◽  
Raman Peak Intensity

In this letter, recent theoretical and experimental investigations of DX centers in Al x Ga 1-x N are reviewed. Due to the technological importance of III–V nitride semiconductors, studies of deep-level defects in AlGaN have attracted a great deal of interest. Oxygen impurities form DX centers in GaN under hydrostatic pressure and in Al x Ga 1-x N alloys. For GaN under pressures greater than 20 GPa, the DX level emerges from the conduction band, leading to a decrease in the free-electron concentration. The localization of free carriers leads to a decrease in the far-infrared absorption and an increase in the LO Raman peak intensity. In Al x Ga 1-x N alloys, Hall effect and persistent photoconductivity measurements indicate that the DX state is energetically favorable for x>0.3. The experimental data for oxygen DX centers are in excellent agreement with first-principles calculations. Experiments have shown that silicon remains a shallow donor up to at least x=0.5 and theory indicates that it may remain shallow up to x=1.

Deposition of Diamond-Like Carbon Films by PECVD

1995 ◽  
Vol 383 ◽  
Author(s):  
Kyu Chang Park ◽  
Soo Chul Chun ◽  
Kyo Jun Song ◽  
Min Park ◽  
Myung Hwan Oh ◽  
...  
Keyword(s):  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Reaction Chamber ◽  
Carbon Films ◽  
Film Structure ◽  
Hard Carbon ◽  
Peak Intensity ◽  
Self Bias ◽  
Raman Peak Intensity

ABSTRACTWe have studied the structural properties of hydrogenated carbon films deposited by plasma enhanced chemical vapor deposition (PECVD). The substrate holder in reaction chamber could be biased and be heated. The Raman peak intensity at 1350 cm−1 was increased by reducing CH4 flow rate. The film structure changed from soft a-C:H to hard carbon with decreasing CH4 flow rate, resulted from increased self-bias. The 1520 cm−1 peak shifts to higher frequency by reducing the CH4flow rate, probably resulted from the increased internal stress.

One-Pot Assembly of Cu2O Chain-Like Hollow Structures

2008 ◽  
Vol 8 (12) ◽  
pp. 6332-6337 ◽  
Author(s):  
Hua Zhang ◽  
Dongfeng Zhang ◽  
Lin Guo ◽  
Rui Zhang ◽  
Penggang Yin ◽  
...  
Keyword(s):  
Hollow Spheres ◽  
Solution Process ◽  
Oriented Attachment ◽  
Interfacial Region ◽  
One Pot ◽  
Hollow Structures ◽  
Peak Intensity ◽  
Hollow Nanostructures ◽  
Oriented Aggregation ◽  
Raman Peak Intensity

Novel Cu2O chain-like network was assembled via a facile one-pot solution process with the assistance of poly(vinylpyrrolidone) (PVP). TEM observations showed that the chain-like structures were aggregated by hollow spheres ∼70 nm in diameter. To be worth mentioning, HRTEM image recorded from the coherent interfacial region demonstrated that the lattice fringes penetrate from one sphere into the adjacent one smoothly without apparent diffraction contrast, which indicated that the hollow spheres experienced lattice fusion and grew into each other. Based on the systematic studies, an oriented aggregation mechanism was proposed, i.e., Cu2O nanoparticles into hollow spheres and subsequently the hollow spheres into the chain-like structures. The Raman spectra of the Cu2O chain-like hollow nanostructures were also investigated. It was found that the Raman peak intensity is different from that in the previous reports, which might be originated from the structure defect resulted from the oriented attachment.

scholarly journals Quantitative evaluation of cement paste carbonation using Raman spectroscopy

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Tangwei Mi ◽  
Yongqiang Li ◽  
Wei Liu ◽  
Weiwen Li ◽  
Wujian Long ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cement Paste ◽  
Underlying Mechanism ◽  
Reinforced Concrete Structures ◽  
Carbonation Depth ◽  
Peak Intensity ◽  
Standard Specimens ◽  
Quantification Analysis ◽  
Raman Peak Intensity ◽  
Good Agreement

AbstractCarbonation induced corrosion is one of the major durability issues for reinforced concrete structures. To address this issue, it is essential to understand the underlying mechanism of carbonation by detecting the ingress of the CO2 and carbonation depth quantitatively. This paper demonstrates the potential of Raman spectroscopy, as a powerful technique, to implement quantification analysis of cement paste carbonation. In present work, the correlation between the content of the CO32− and the Raman peak intensity was initially established by using several standard specimens premixed with certain amount of CO32−. The established correlation was then used to investigate the carbonation of the cement paste in a CO2 diffusion scenario, and the results show a good agreement with that obtained by thermogravimetry measurements. Therefore, the feasibility of the Raman spectroscopy to quantify the carbonation degree of the cement paste can be demonstrated.

Resolution Attainable With the Present Day STEM

1973 ◽  
Vol 31 ◽  
pp. 230-231 ◽  
Author(s):  
J. S. Wall ◽  
J. P. Langmore ◽  
H. Isaacson ◽  
A. V. Crewe
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Incident Beam ◽  
Scanning Transmission Electron Microscope ◽  
Aperture Size ◽  
Magnetic Lens ◽  
Peak Intensity ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Half Angle

The scanning transmission electron microscope (STEM) constructed by the authors employs a field emission gun and a 1.15 mm focal length magnetic lens to produce a probe on the specimen. The aperture size is chosen to allow one wavelength of spherical aberration at the edge of the objective aperture. Under these conditions the profile of the focused spot is expected to be similar to an Airy intensity distribution with the first zero at the same point but with a peak intensity 80 per cent of that which would be obtained If the lens had no aberration. This condition is attained when the half angle that the incident beam subtends at the specimen, 𝛂 = (4𝛌/Cs)¼

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

Ultrafast laser micro-nano structured superhydrophobic teflon surfaces for enhanced SERS detection via evaporation concentration

2020 ◽  
Vol 9 (1-2) ◽  
pp. 89-100 ◽  
Author(s):  
Xinyu Hu ◽  
Rui Pan ◽  
Mingyong Cai ◽  
Weijian Liu ◽  
Xiao Luo ◽  
...  
Keyword(s):  
Rhodamine 6G ◽  
Optimal Parameter ◽  
Solute Concentration ◽  
Processing Parameter ◽  
Detection Techniques ◽  
Peak Intensity ◽  
Target Analytes ◽  
Sers Detection ◽  
Scanning Path ◽  
Evaporation Concentration

AbstractEvaporation concentration of target analytes dissolved in a water droplet based on superhydrophobic surfaces could be able to break the limits for sensitive trace substance detection techniques (e.g. SERS) and it is promising in the fields such as food safety, eco-pollution, and bioscience. In the present study, polytetrafluoroethylene (PTFE) surfaces were processed by femtosecond laser and the corresponding processing parameter combinations were optimised to obtain surfaces with excellent superhydrophobicity. The optimal parameter combination is: laser power: 6.4 W; scanning spacing: 40 μm; scanning number: 1; and scanning path: 90 degree. For trapping and localising droplets, a tiny square area in the middle of the surface remained unprocessed for each sample. The evaporation and concentration processes of droplets on the optimised surfaces were performed and analyzed, respectively. It is shown that the droplets with targeted solute can successfully collect all solute into the designed trapping areas during evaporation process on our laser fabricated superhydrophobic surface, resulting in detection domains with high solute concentration for SERS characterisation. It is shown that the detected peak intensity of rhodamine 6G with a concentration of 10−6m in SERS characterisation can be obviously enhanced by one or two orders of magnitude on the laser fabricated surfaces compared with that of the unprocessed blank samples.

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