scholarly journals Synthesis of Natural-Like Snow by Ultrasonic Nebulization of Water: Morphology and Raman Characterization

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4458
Author(s):  
Ettore Maggiore ◽  
Matteo Tommasini ◽  
Paolo M. Ossi
Keyword(s):  
Raman Spectroscopy ◽  
Production Method ◽  
Optical Microscope ◽  
Low Density ◽  
Effective Strategy ◽  
Ultrasonic Nebulization ◽  
Raman Characterization ◽  
Snow Samples

The current devices used to produce massive amounts of snow (i.e., snow machines) can be improved with concern to both the energy efficiency and the quality of snow. Here we investigate an alternative snow production method based on the ultrasonic nebulization of water and its subsequent condensation on the cold surfaces of a refrigerator. Inspection of the snow samples with a stereo optical microscope shows both dendritic and granular snow morphologies. The characterization of the samples by Raman spectroscopy shows a behavior consistent with that of a natural, low-density snow. Our results indicate that ultrasonic nebulization of water is an effective strategy for producing natural-like snow at the laboratory scale.

scholarly journals Identification of LDPE Grades Focusing on Specific CH2 Raman Vibration Modes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Richard Jumeau ◽  
Patrice Bourson ◽  
Michel Ferriol ◽  
François Lahure ◽  
Marc Ponçot ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Vibrational Spectroscopy ◽  
Phenomenological Model ◽  
Low Density ◽  
Vibration Modes ◽  
Scanning Calorimetry ◽  
Lamella Thickness ◽  
Poly Ethylene

The possibilities of applications of vibrational spectroscopy techniques (Raman spectroscopy) in the analysis and characterization of polymers are more and more used and accurate. In this paper, our purpose is to characterize Low Density Poly(Ethylene) (LDPE) grades by Raman spectroscopy and in particular with CH2 Raman vibration modes. With temperature measurements, we determine different amorphous and crystalline Raman assignments. From these results and on the basis of the evolution of CH2 bending Raman vibration modes, we develop a phenomenological model in correlation with Differential Scanning Calorimetry and in particular with crystalline lamella thickness determination.

scholarly journals Raman characterization of the optical phonons in AlxGa1−xN layers grown by MBE and MOCVD

1997 ◽  
Vol 2 ◽  
Author(s):  
A. Cros ◽  
H. Angerer ◽  
R. Handschuh ◽  
O. Ambacher ◽  
M. Stutzmann
Keyword(s):  
Phonon Mode ◽  
Aluminum Content ◽  
Composition Range ◽  
Theoretical Calculations ◽  
Phonon Modes ◽  
Sapphire Substrates ◽  
Mode Behavior ◽  
Raman Characterization

We present the results of Raman measurements performed on AlxGa1−xN layers grown by MBE and MOCVD. The films were deposited on (0001) c-sapphire substrates, and the aluminum content covered the whole composition range for x from 0 (GaN) to 1 (AlN). It is shown that the energies of both A1(TO) and A1(LO) phonon modes smoothly increase with increasing x, indicating a one-mode behavior. The E2 phonon mode, however, presents a different behavior. Its energy increases very slowly with aluminum content and, for x≈0.4, a new phonon mode shows up which is shifted to higher energies by 50 cm−1. This new line leads to the E2 AlN mode for increasing aluminum content. The linewidths and intensities of these modes strongly depend on composition. These results are compared with recent theoretical calculations. Finally, the Raman selection rules in the MBE and MOCVD samples are compared and conclusions about the quality of the layers are drawn.

Raman Spectroscopy of Graphitic Foams

2004 ◽  
Vol 851 ◽  
Author(s):  
Eduardo B. Barros ◽  
Nasser S. Demir ◽  
Antonio G. Souza Filho ◽  
Josué Medes Filho ◽  
Ado Jorio ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
National Laboratory ◽  
Weight Ratio ◽  
Spectroscopy Study ◽  
Oak Ridge ◽  
Very High ◽  
Graphitic Foam

ABSTRACTTo better understand the very high thermal conductivity to weight ratio of the graphitic foams recently developed at the Oak Ridge National Laboratory, a Raman spectroscopy study was performed. It was also shown that the Raman scattering can be useful for the characterization of the graphitic foam, being able to evaluate the quality of the samples with respect to the density and location of lattice defects.

Preparation and Characterization of SiC Coating on Graphite Substrate

2014 ◽  
Vol 602-603 ◽  
pp. 412-415 ◽  
Author(s):  
Yan Li Huo ◽  
Shu Guang Chen ◽  
Hai Long Liang ◽  
Chun Peng Wang ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Cross Section ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Optical Microscope ◽  
Chemical Vapor Infiltration ◽  
Good Combination ◽  
Graphite Substrate

High thermal conductivity and dense SiC coating were fabricated by chemical vapor deposition (CVD) on surface of different graphite at temperature of 1100°C. The results indicated that the thickness of the coating influences the quality of coating. There was no crack in coating when thickness of the coating is less than 0.3mm. The structure of graphite affected the reaction badly. When the graphite is coarse and porous the reaction is chemical vapor infiltration (CVI) and the interface of coating and substrate isnt obvious. When the graphite is dense and smooth, the coating is covered in surface of graphite, the interface is found between the coating and substrate. Optical microscope and SEM were used to observe the surface and cross-section morphology and microstructure of coatings. It shown coating and substrate had a good combination and the deposited grains mainly showed equiaxed form with the crystallite size of 30 nm at 1100°C.

Characterization of Structural Quality of Bonded Silicon-On-Insulator Wafers by Spectroscopic Ellipsometry and Raman Spectroscopy

2004 ◽  
Vol 809 ◽  
Author(s):  
N. V. Nguyen ◽  
J. E. Maslar ◽  
Jin-Yong Kim ◽  
Jin-Ping Han ◽  
Jin-Won Park ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Crystalline Silicon ◽  
Silicon On Insulator ◽  
Structural Defects ◽  
Structural Quality ◽  
Ellipsometry Data

ABSTRACTThe crystalline quality of bonded Silicon-On-Insulator (SOI) wafers were examined by spectroscopic ellipsometry and Raman spectroscopy. Both techniques detect slight structural defects in the SOI layer. If a pure crystalline silicon dielectric function is assumed for the SOI layer, the spectroscopic ellipsometry data fitting yields an unacceptably large discrepancy between the experimental and modeled data. The best fits for all the samples result in a dielectric function of the SOI layer that consists of a physical mixture of crystalline silicon and about 4 % to 7 % of amorphous silicon. Using such a mixture indicates that there are still some defects in the SOI layer when compared with the high-quality bulk crystalline silicon. This observation is further supported by Raman spectroscopy measurements. The Raman spectra of all SOI samples exhibit a feature at about 495 cm−1 that is not observed in the crystalline silicon spectrum. Features similar to the 495 cm−1 feature have been reported in the literature and attributed to dislocations or faults in the silicon lattice.

Raman scattering characterization of (100) and (111) oriented diamond films grown in the same run by hot filament chemical vapor deposition

1994 ◽  
Vol 9 (11) ◽  
pp. 2839-2844 ◽  
Author(s):  
G. Popovici ◽  
S. Khasawinah ◽  
T. Sung ◽  
M.A. Prelas ◽  
B.V. Spitsyn ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Deposition ◽  
Chemical Vapor ◽  
Infrared Excitation ◽  
Hot Filament

The crystalline quality of a diamond film with two different preferential orientations (100) and (111), obtained in the same run by hot filament chemical deposition, has been studied. The quality of the film determined by Raman spectroscopy measurements was found to be nearly the same for both orientations. The second order Raman spectrum for diamond film was observed by using an infrared excitation.

scholarly journals Study of the Degree of Cure through Thermal Analysis and Raman Spectroscopy in Composite-Forming Processes

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3991 ◽  
Author(s):  
Juan A. García-Manrique ◽  
Bernabé Marí ◽  
Amparo Ribes-Greus ◽  
Llúcia Monreal ◽  
Roberto Teruel ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Characterization ◽  
Degree Of Polymerization ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Degree Of Cure ◽  
Composite Forming ◽  
Out Of Autoclave

The curing of composite materials is one of the parameters that most affects their mechanical behavior. The inspection methods used do not always allow a correct characterization of the curing state of the thermosetting resins. In this work, Raman spectroscopy technology is used for measuring the degree of cure. The results are compared with conventional thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscope (SEM). Carbon fiber specimens manufactured with technologies out of autoclave (OoA) have been used, with an epoxy system Prepreg System, SE 84LV. The results obtained with Raman technology show that it is possible to verify the degree of polymerization, and the information is complementary from classical thermal characterization techniques such as TGA and DSC; thus, it is possible to have greater control in curing and improving the quality of the manufactured parts.

scholarly journals The non-linear optical crystal growth and characterization of piperizantum p- aminobentzone

BIBECHANA ◽  
2018 ◽  
Vol 16 ◽  
pp. 15-22
Author(s):  
M Vallikkodi ◽  
S Sudhahar
Keyword(s):  
Raman Spectroscopy ◽  
Nonlinear Optical ◽  
Ultra Violet ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Optical Crystal

The nonlinear optical properties of piperizanium p – aminobenzoate (PZPAB) crystal were successfully grown with the help of temperature gradient (Slow evaporation) method. The good quality of PZPAB single crystal is formed. The PZPAB is characterized with the help of X-ray diffraction (XRD), Fourier transform infrared (FTIR) measurement, photoluminescence (PL), Raman spectroscopy, ultra violet visible spectroscopy (UV) and finally etching analysis was done.BIBECHANA 6 (2019) 5-22

Characterization of carbon nano-materials by apertureless near-field scanning optical microscope-Raman spectroscopy

2012 ◽  
Author(s):  
Kyoung-Duck Park ◽  
Yong Hwan Kim ◽  
Jin Ho Park ◽  
Jung Su Park ◽  
Young-Hee Lee ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Near Field ◽  
Optical Microscope ◽  
Nano Materials ◽  
Near Field Scanning

scholarly journals Microscopic And Spectroscopic Research Of The MWCNTs-Re Nanocomposites

2015 ◽  
Vol 60 (3) ◽  
pp. 2047-2052 ◽  
Author(s):  
A.D. Dobrzańska-Danikiewicz ◽  
W. Wolany ◽  
D. Cichocki ◽  
D. Łukowiec
Keyword(s):  
Raman Spectroscopy ◽  
Comparative Analysis ◽  
High Temperature ◽  
Manufacturing Process ◽  
Covalent Modification ◽  
Band Intensity ◽  
Structural Defects ◽  
Forms Of Carbon

Abstract The combination of TEM research and Raman spectroscopy to characterization of MWNTs-Re nanocomposites gives a new notion about the structure and quality of materials obtained. TEM studies indicate that the functionalization method significantly influences the morphology of obtained MWCNTs-Re nanocomposites. Due to the specific spectrum recorded for the MWCNTs they can be distinguished from other forms of carbon, furthermore comparative analysis of the results at different stages of the manufacturing process confirms the covalent modification of the MWCNTs structure. The D-band intensity compared to the G-band intensity provides valuable information about the quality of the sample, in particular indicates the existence of contamination and/or the presence of structural defects. Preliminary results suggest that the high-temperature manufacturing process of MWCNTs-Re nanocomposite improves the quality of the carbon material intended for the experiment.

Sign in / Sign up

Export Citation Format

Share Document