Determination of Temperature-Dependent Stress in SiC MOSFETs by Raman Spectroscopy

Recently there has been upsurge in reports that illicit seizures of cocaine and heroin have been adulterated with fentanyl. Surface-enhanced Raman spectroscopy (SERS) provides a useful alternative to current screening procedures that permits detection of trace levels of fentanyl in mixtures. Samples are solubilized and allowed to interact with aggregated colloidal nanostars to produce a rapid and sensitive assay. In this study, we present the quantitative determination of fentanyl in heroin and cocaine using SERS, using a point-and-shoot handheld Raman system. Our protocol is optimized to detect pure fentanyl down to 0.20 ± 0.06 ng/mL and can also distinguish pure cocaine and heroin at ng/mL levels. Multiplex analysis of mixtures is enabled by combining SERS detection with principal component analysis and super partial least squares regression discriminate analysis (SPLS-DA), which allow for the determination of fentanyl as low as 0.05% in simulated seized heroin and 0.10% in simulated seized cocaine samples.

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Quantitative Determination of Oxytetracycline in Water-Based Liquid Dosage Forms by Raman Spectroscopy

Journal of Applied Spectroscopy ◽

10.1007/s10812-021-01147-x ◽

2021 ◽

Author(s):

A. Yu. Khrushchev ◽

E. R. Akmaev ◽

V. O. Bondarenko ◽

I. V. Kis

Keyword(s):

Raman Spectroscopy ◽

Quantitative Determination ◽

Dosage Forms ◽

Water Based

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Temperature Dependence of G and D’ Phonons in Monolayer to Few-Layer Graphene with Vacancies

Nanoscale Research Letters ◽

10.1186/s11671-020-03414-w ◽

2020 ◽

Vol 15 (1) ◽

Author(s):

Mingming Yang ◽

Longlong Wang ◽

Xiaofen Qiao ◽

Yi Liu ◽

Yufan Liu ◽

...

Keyword(s):

Negative Temperature Coefficient ◽

Negative Temperature ◽

Intrinsic Properties ◽

Temperature Dependent ◽

Phonon Interaction ◽

Electron Phonon Interaction ◽

Layer Graphene ◽

A Value ◽

Few Layer Graphene

Abstract The defects into the hexagonal network of a sp2-hybridized carbon atom have been demonstrated to have a significant influence on intrinsic properties of graphene systems. In this paper, we presented a study of temperature-dependent Raman spectra of G peak and D’ band at low temperatures from 78 to 318 K in defective monolayer to few-layer graphene induced by ion C+ bombardment under the determination of vacancy uniformity. Defects lead to the increase of the negative temperature coefficient of G peak, with a value almost identical to that of D’ band. However, the variation of frequency and linewidth of G peak with layer number is contrary to D’ band. It derives from the related electron-phonon interaction in G and D’ phonon in the disorder-induced Raman scattering process. Our results are helpful to understand the mechanism of temperature-dependent phonons in graphene-based materials and provide valuable information on thermal properties of defects for the application of graphene-based devices.

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Determination of ferroelastic phase transition temperature in BiVO4 by Raman spectroscopy

Materials Letters ◽

10.1016/j.matlet.2021.129519 ◽

2021 ◽

Vol 291 ◽

pp. 129519

Author(s):

Yuwaraj K. Kshetri ◽

Bina Chaudhary ◽

Takashi Kamiyama ◽

Tae-Ho Kim ◽

Federico Rosei ◽

...

Keyword(s):

Phase Transition ◽

Raman Spectroscopy ◽

Transition Temperature ◽

Phase Transition Temperature ◽

Ferroelastic Phase Transition

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On the nature of the phase transitions of aluminosilicate perrhenate sodalite

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2020-0027 ◽

2020 ◽

Vol 235 (6-7) ◽

pp. 213-223

Author(s):

Hilke Petersen ◽

Lars Robben ◽

Thorsten M. Gesing

Keyword(s):

Raman Spectroscopy ◽

Phase Transitions ◽

Decomposition Temperature ◽

Second Phase ◽

Structure Property ◽

X Ray Diffraction ◽

Temperature Dependent ◽

Two Phase ◽

Structure Property Relationships ◽

Heat Capacity Measurements

AbstractThe temperature-dependent structure-property relationships of the aluminosilicate perrhenate sodalite |Na8(ReO4)2|[AlSiO4]6 (ReO4-SOD) were analysed via powder X-ray diffraction (PXRD), Raman spectroscopy and heat capacity measurements. ReO4-SOD shows two phase transitions in the investigated temperature range (13 K < T < 1480 K). The first one at 218.6(1) K is correlated to the transition of dynamically ordered $P\overline{4}3n$ (> 218.6(1 K) to a statically disordered (<218.6(1) K) SOD template in $P\overline{4}3n$. The loss of the dynamics of the template anion during cooling causes an increase of disorder, indicated by an unusual intensity decrease of the 011-reflection and an increase of the Re-O2 bond length with decreasing temperature. Additionally, Raman spectroscopy shows a distortion of the ReO4 anion. Upon heating the thermal expansion of the sodalite cage originated in the tilt-mechanism causes the second phase transition at 442(1) K resulting in a symmetry-increase from $P\overline{4}3n$ to $Pm\overline{3}n$, the structure with the sodalites full framework expansion. Noteworthy is the high decomposition temperature of 1320(10) K.

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Selectivity of Tungsten Oxide Synthesized by Sol-Gel Method Towards Some Volatile Organic Compounds and Gaseous Materials in a Broad Range of Temperatures

Materials ◽

10.3390/ma13030523 ◽

2020 ◽

Vol 13 (3) ◽

pp. 523 ◽

Cited By ~ 4

Author(s):

Simonas Ramanavičius ◽

Milda Petrulevičienė ◽

Jurga Juodkazytė ◽

Asta Grigucevičienė ◽

Arūnas Ramanavičius

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Sol Gel ◽

Temperature Dependent ◽

Sensing Systems ◽

Sensing Material ◽

Operational Temperature ◽

Volatile Organic ◽

Different Gases

In this research, the investigation of sensing properties of non-stoichiometric WO3 (WO3−x) film towards some volatile organic compounds (VOC) (namely: Methanol, ethanol, isopropanol, acetone) and ammonia gas are reported. Sensors were tested at several temperatures within the interval ranging from a relatively low temperature of 60 up to 270 °C. Significant variation of selectivity, which depended on the operational temperature of sensor, was observed. Here, the reported WO3/WO3–x-based sensing material opens an avenue for the design of sensors with temperature-dependent sensitivity, which can be applied in the design of new gas- and/or VOC-sensing systems that are dedicated for the determination of particular gas- and/or VOC-based analyte concentration in the mixture of different gases and/or VOCs, using multivariate analysis of variance (MANOVA).

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