1,905 results match your criteria raman pulse


Simultaneous opto-electrochemical monitoring of carbamazepine and its electro-oxidation by-products in wastewater.

J Hazard Mater 2021 Jun 29;419:126509. Epub 2021 Jun 29.

Gdańsk University of Technology, Gdansk, Poland.

The growing human impact on aquatic environments deriving from the extensive use of pharmaceuticals and the release of persistent pollutants necessitates the implementation of new, widespread methods for characterising and quantifying such contaminants and their related degradation products. Carbamazepine, 5 H-dibenzo[b,f]azepine-5-carboxamide, (CBZ) is a widely used anti-epileptic drug characterised by limited removal by conventional wastewater treatments and high persistency in the environment. In this work, CBZ detection and quantification was performed in phosphate buffer, as well as in samples of complex matrix-like landfill leachates and treated wastewater originating from a medical facility, and simultaneously by optical and electrochemical methods using a novel transparent carbon-based nanostructured electrode. Read More

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Impact of Single-Pulse, Low-Intensity Laser Post-Processing on Structure and Activity of Mesostructured Cobalt Oxide for the Oxygen Evolution Reaction.

ACS Appl Mater Interfaces 2021 Jul 29. Epub 2021 Jul 29.

Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany.

Herein, we report nanosecond, single-pulse laser post-processing (PLPP) in a liquid flat jet with precise control of the applied laser intensity to tune structure, defect sites, and the oxygen evolution reaction (OER) activity of mesostructured CoO. High-resolution X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS) are consistent with the formation of cobalt vacancies at tetrahedral sites and an increase in the lattice parameter of CoO after the laser treatment. X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) further reveal increased disorder in the structure and a slight decrease in the average oxidation state of the cobalt oxide. Read More

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Femtosecond Laser-Induced Crystallization of Amorphous Silicon Thin Films under a Thin Molybdenum Layer.

ACS Appl Mater Interfaces 2021 Jul 28. Epub 2021 Jul 28.

National Centre for Laser Applications (NCLA), School of Physics, National University of Ireland Galway, Galway H91 TK33, Ireland.

A new process to crystallize amorphous silicon without melting and the generation of excessive heating of nearby components is presented. We propose the addition of a molybdenum layer to improve the quality of the laser-induced crystallization over that achieved by direct irradiation of silicon alone. The advantages are that it allows the control of crystallite size by varying the applied fluence of a near-infrared femtosecond laser. Read More

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Arsenic-Doped SnSe Thin Films Prepared by Pulsed Laser Deposition.

ACS Omega 2021 Jul 30;6(27):17483-17491. Epub 2021 Jun 30.

Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic.

Pulsed UV laser deposition was exploited for the preparation of thin Sn As Se ( = 0, 0.05, 0.5, and 2. Read More

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Quercetin-rGO based mercury-free electrode for the determination of toxic Cd (II) and Pb (II) ions using DPASV technique.

Environ Res 2021 Jul 16;202:111707. Epub 2021 Jul 16.

Department of Analytical Chemistry, School of Chemical Science, University of Madras, Guindy Campus, Chennai, Tamil Nadu, 600025, India. Electronic address:

Metal ion pollution poses serious threat to environment. Analysis of Cd (II) and Pb (II) ions using chemically modified mercury free electrode is a feasible routine analytical tool. Developing an electrode surface modified with conductive 2D carbon and metal complexing ligand created a synergetic effect towards sensitive and selective electrochemical determination of metal ions. Read More

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Pump-depletion dynamics and saturation of stimulated Brillouin scattering in shock ignition relevant experiments.

Phys Rev E 2021 Jun;103(6-1):063208

Inertial Fusion Technology, General Atomics, San Diego, California 92121, USA.

As an alternative inertial confinement fusion scheme, shock ignition requires a strong converging shock driven by a high-intensity laser pulse to ignite a precompressed fusion capsule. Understanding nonlinear laser-plasma instabilities is crucial to assess and improve the laser-shock energy coupling. Recent experiments conducted on the OMEGA EP laser facility have demonstrated that such instabilities can ∼100% deplete the first 0. Read More

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Measuring the effective height for atom gravimeters by applying a frequency jump to Raman lasers.

Rev Sci Instrum 2021 Jun;92(6):063202

MOE Key Laboratory of Fundamental Quantities Measurement, Hubei Key Laboratory of Gravitation and Quantum Physics, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.

As the existence of the gravity gradient, the output of gravimeters is actually the gravitational acceleration at the reference instrumental height. Precise knowledge of the reference height is indispensable in the utilization of gravity measurements, especially for absolute gravimeters. Here, we present an interferometric method to measure the distance between the atomic cloud and a reflecting mirror directly, which consequently determines the reference height of our atom gravimeter. Read More

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Mapping wave packet bifurcation at a conical intersection in CHI by attosecond XUV transient absorption spectroscopy.

J Chem Phys 2021 Jun;154(23):234301

Department of Chemistry, University of California, Berkeley, California 94720, USA.

Extreme ultraviolet (XUV) transient absorption spectroscopy has emerged as a sensitive tool for mapping the real-time structural and electronic evolution of molecules. Here, attosecond XUV transient absorption is used to track dynamics in the A-band of methyl iodide (CHI). Gaseous CHI molecules are excited to the A-band by a UV pump (277 nm, ∼20 fs) and probed by attosecond XUV pulses targeting iodine I(4d) core-to-valence transitions. Read More

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Site-specific generation of excited state wavepackets with high-intensity attosecond x rays.

J Chem Phys 2021 Jun;154(22):224111

Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, USA.

High-intensity attosecond x rays can produce coherent superpositions of valence-excited states through two-photon Raman transitions. The broad-bandwidth, high-field nature of the pulses results in a multitude of accessible excited states. Multiconfigurational quantum chemistry with the time-dependent Schrödinger equation is used to examine population transfer dynamics in stimulated x-ray Raman scattering of the nitric oxide oxygen and nitrogen K-edges. Read More

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Study of Micro/Nano Structuring and Mechanical Properties of KrF Excimer Laser Irradiated Al for Aerospace Industry and Surface Engineering Applications.

Materials (Basel) 2021 Jun 30;14(13). Epub 2021 Jun 30.

Department of Physics, Comsats Institute of Information Technology, Islamabad 12000, Pakistan.

Micro/nano structuring of KrF Excimer laser-irradiated Aluminum (Al) has been correlated with laser-produced structural and mechanical changes. The effect of non-reactive Argon (Ar) and reactive Oxygen (O) environments on the surface, structural and mechanical characteristics of nano-second pulsed laser-ablated Aluminum (Al) has been revealed. KrF Excimer laser with pulse duration 20 ns, central wavelength of 248 nm and repetition rate of was utilized for this purpose. Read More

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Substrate Impact on MR Characteristics of Carbon Nano Films Explored via AFM and Raman Analysis.

Materials (Basel) 2021 Jun 30;14(13). Epub 2021 Jun 30.

Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.

Recent advances in the fabrication and classification of amorphous carbon (a-Carbon) thin films play an active part in the field of surface materials science. In this paper, a pulsed laser deposition (PLD) technique through controlling experimental parameters, including deposition time/temperature and laser energy/frequency, has been employed to examine the substrate effect of amorphous carbon thin film fabrication over SiO and glass substrates. In this paper, we have examined the structural and magnetoresistance (MR) properties of these thin films. Read More

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Single Photon Avalanche Diode Arrays for Time-Resolved Raman Spectroscopy.

Sensors (Basel) 2021 Jun 23;21(13). Epub 2021 Jun 23.

Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Via G. Ponzio 34/5, 20133 Milano, Italy.

The detection of peaks shifts in Raman spectroscopy enables a fingerprint reconstruction to discriminate among molecules with neither labelling nor sample preparation. Time-resolved Raman spectroscopy is an effective technique to reject the strong fluorescence background that profits from the time scale difference in the two responses: Raman photons are scattered almost instantaneously while fluorescence shows a nanoseconds time constant decay. The combination of short laser pulses with time-gated detectors enables the collection of only those photons synchronous with the pulse, thus rejecting fluorescent ones. Read More

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Nanosecond pulsed deep-red laser source by intracavity frequency-doubled crystalline Raman laser.

Opt Lett 2021 Jul;46(13):3207-3210

We demonstrated a deep-red laser source by intracavity frequency-doubled crystalline Raman laser for the first time, to the best of our knowledge. The actively -switched 1314 nm : laser was first converted to the eye-safe Raman laser using a () (KGW) crystal, which was subsequently frequency-doubled in a bismuth borate crystal. Benefiting from the KGW bi-axial properties, the deep-red laser source was able to lase separately at two different spectral lines at 730 and 745 nm. Read More

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Efficient charge-transfer from diketopyrrolopyrroles to single-walled carbon nanotubes.

Nanoscale 2021 Jul;13(26):11544-11551

Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany.

In this contribution, the excited state charge-transfer interactions between single-walled carbon nanotubes (SWCNTs) and a variety of phenyl, 4-bromophenyl, and thiophene substituted diketopyrrolopyrroles (DPPs), is described. Atomic force microscopy (AFM) and aberration corrected high resolution transmission electron microscopy (AC-HRTEM) corroborated the successful formation of DPP/SWCNTs. Steady-state absorption, fluorescence, and Raman spectroscopies all gave insights into the impact on their ground and excited states as well as on the nature of their electronic communication/interaction. Read More

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Resonant Stimulated X-ray Raman Spectroscopy of Mixed-Valence Manganese Complexes.

J Phys Chem Lett 2021 Jul 22;12(25):5925-5931. Epub 2021 Jun 22.

Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697, United States.

Resonant stimulated X-ray Raman spectroscopy of the bimetallic [MnMn(μ-O)(μ-OAC)(tacn)] manganese complex is investigated in a simulation study. Essential biological processes, including water oxidation in photosynthesis, involve charge transfer between manganese sites of different oxidation states. We study a prototypical binuclear mixed-valence transition-metal complex with two Mn atoms in different oxidation states surrounded by ligand structures and employ a pump-probe sequence of resonant X-ray Raman excitations to follow the charge transfer occurring in the molecule. Read More

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Converting noise into solitons: optical self-organization through intermodal nonlinearity.

Opt Express 2021 Jun;29(12):18315-18324

We experimentally demonstrate a pump-pulse-induced conversion of noise into solitons in multimode optical fibers. The process is based on the recently discovered phenomenon of soliton self-mode conversion, where a pump soliton in a higher-order spatial mode crafts another well-defined soliton, originating purely from noise, in a lower-order mode at a longer wavelength through intermodal Raman scattering. The lack of the need for any seed or cavity feedback demonstrates that soliton self-mode conversion is a fundamentally unavoidable, but nevertheless tailorable and hence useful, self-organizing nonlinear optical effect capable of turning noise into transform limited solitons. Read More

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Microneedle-based devices for point-of-care infectious disease diagnostics.

Acta Pharm Sin B 2021 Feb 16. Epub 2021 Feb 16.

School of Pharmacy, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK.

Recent infectious disease outbreaks, such as COVID-19 and Ebola, have highlighted the need for rapid and accurate diagnosis to initiate treatment and curb transmission. Successful diagnostic strategies critically depend on the efficiency of biological sampling and timely analysis. However, current diagnostic techniques are invasive/intrusive and present a severe bottleneck by requiring specialist equipment and trained personnel. Read More

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February 2021

Transient FTIR spectroscopy after one- and two-colour excitation on a highly luminescent chromium(III) complex.

Phys Chem Chem Phys 2021 Jun;23(25):13808-13818

Department of Chemistry and Research Center OPTIMAS, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany.

The development of photoactive transition metal complexes with Earth-abundant metals is a rapidly growing research field, where a deeper understanding of the underlying photophysical processes is of great importance. A multitude of potential applications in the fields of photosensitizing, optical sensing, photoluminescence and photoredox catalysis motivates demanding spectroscopic studies. We applied a series of high-level spectroscopic methods on the previously reported highly luminescent chromium(iii) complex [Cr(ddpd)2](BF4)3 (ddpd = N,N'-dimethyl-N,N'-dipyridine-2-ylpyridine-2,6-diamine) possessing two near-IR emissive doublet states with microsecond lifetimes. Read More

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Photon echoes and two dimensional spectra of the amide I band of proteins measured by femtosecond IR - Raman spectroscopy.

Authors:
Paul M Donaldson

Chem Sci 2020 Jul 27;11(33):8862-8874. Epub 2020 Jul 27.

Central Laser Facility, RCaH, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus Didcot OX11 0QX UK

Infrared (IR) and Raman spectroscopy are fundamental techniques in chemistry, allowing the convenient determination of bond specific chemical composition and structure. Over the last decades, ultrafast multidimensional IR approaches using sequences of femtosecond IR pulses have begun to provide a new means of gaining additional information on molecular vibrational couplings, distributions of molecular structures and ultrafast molecular structural dynamics. In this contribution, new approaches to measuring multidimensional spectra involving IR and Raman processes are presented and applied to the study of the amide I band of proteins. Read More

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Tracking Ultrafast Structural Dynamics by Time-Domain Raman Spectroscopy.

J Am Chem Soc 2021 Jul 7;143(26):9699-9717. Epub 2021 Jun 7.

Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan.

In traditional Raman spectroscopy, narrow-band light is irradiated on a sample, and its inelastic scattering, i.e., Raman scattering, is detected. Read More

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Electrochemical detection of hydrocortisone using green-synthesized cobalt oxide nanoparticles with nafion-modified glassy carbon electrode.

Chemosphere 2021 May 28;282:131029. Epub 2021 May 28.

Department of Bionanotechnology, Gachon University, Gyeonggi-Do, 13120, Republic of Korea. Electronic address:

Developing highly sensitive and selective sensors is important for the detection of steroid hormones. Electrochemical sensors are of great interest in this regard. Also utilization of bio-derived substances as an electrode material is environment friendly. Read More

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Sandpaper-based electrochemical devices assembled on a reusable 3D-printed holder to detect date rape drug in beverages.

Talanta 2021 Sep 20;232:122408. Epub 2021 Apr 20.

Instituto de Química, Universidade Federal de Goiás, 74690-900, Goiânia, GO, Brazil; Instituto Nacional de Ciência e Tecnologia de Bioanalítica, 13083-861, Campinas, SP, Brazil. Electronic address:

This study describes the development of a new electrochemical paper-based analytical device (ePAD) on alumina sandpaper substrate through a pencil-drawing process for square wave voltammetry measurements of midazolam maleate used as a "date rape drug" in beverages. The proposed ePAD was assembled on a reusable 3D printed holder to delimit its geometric area and ensure better robustness. The ePAD was characterized by scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and Raman spectroscopy. Read More

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September 2021

Plastic Antibody of Polypyrrole/Multiwall Carbon Nanotubes on Screen-Printed Electrodes for Cystatin C Detection.

Biosensors (Basel) 2021 May 31;11(6). Epub 2021 May 31.

Biomedical Engineering Laboratory, Federal University of Pernambuco, Recife-PE 50670-901, Brazil.

This work reports the design of a novel plastic antibody for cystatin C (Cys-C), an acute kidney injury biomarker, and its application in point-of-care (PoC) testing. The synthetic antibody was obtained by tailoring a molecularly imprinted polymer (MIP) on a carbon screen-printed electrode (SPE). The MIP was obtained by electropolymerizing pyrrole (Py) with carboxylated Py (Py-COOH) in the presence of Cys-C and multiwall carbon nanotubes (MWCNTs). Read More

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Temporal and spectral unmixing of photoacoustic signals by deep learning.

Opt Lett 2021 Jun;46(11):2690-2693

Improving the imaging speed of multi-parametric photoacoustic microscopy (PAM) is essential to leveraging its impact in biomedicine. However, to avoid temporal overlap, the A-line rate is limited by the acoustic speed in biological tissues to a few megahertz. Moreover, to achieve high-speed PAM of the oxygen saturation of hemoglobin, the stimulated Raman scattering effect in optical fibers has been widely used to generate 558 nm from a commercial 532 nm laser for dual-wavelength excitation. Read More

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Tunable-shift stimulated Raman scattering in water by chirped 50  fs to 4.5  ps UV-pulses.

Opt Lett 2021 Jun;46(11):2686-2689

Forward stimulated Raman scattering (SRS) induced by focused 400 nm pulses chirped to different pulse durations is observed in water and heavy water. The first Stokes Raman peak shift is shown to be tunable in the range of ${{3500 {-} 4200}}\;{{\rm{cm}}^{- 1}}$ in water and ${{2450 {-} 3250}}\;{{\rm{cm}}^{- 1}}$ in heavy water. It is demonstrated that the Stokes peak shift increases for shorter pulse durations and higher intensities. Read More

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Interference-free electrocatalysis of p-chloro meta xylenol (PCMX) on uniquely designed optimized polymeric nanohybrid of P(EDOT-co-OPD) and fMWCNT modified glassy carbon electrode.

Anal Chim Acta 2021 Jul 4;1168:338595. Epub 2021 May 4.

Pollution Control Laboratory, Department of Chemical Engineering, Jadavpur University, 188, Raja Subodh Chandra Mallick Road, Kolkata, 700032, West Bengal, India. Electronic address:

p-Chloro-meta-Xylenol (PCMX) is an environmentally hazardous phenolic compound having biocidal and antiseptic activity. Very few research publications addressed monitoring this contaminant. This paper presents a rapid sensing system to quantify it in waste water samples. Read More

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Label-free electrochemical immunosensor based on gold nanoparticle/polyethyleneimine/reduced graphene oxide nanocomposites for the ultrasensitive detection of cancer biomarker matrix metalloproteinase-1.

Analyst 2021 Jun;146(12):4066-4079

Department of Chemical Engineering and Biotechnology, National Taipei University of Technology (Taipei Tech), Taipei 10608, Taiwan.

Matrix metalloproteinase-1 (MMP-1) is associated with many types of cancers, including oral, colorectal, and brain cancers. This paper describes the fabrication of an MMP-1 immunosensor based on a gold nanoparticle/polyethyleneimine/reduced graphene oxide (AuNP/PEI/rGO)-modified disposable screen-printed electrode (SPE). A microwave-assisted single-step method was employed for the simultaneous reduction of gold and graphene oxide in a PEI environment to avoid AuNP agglomeration. Read More

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Coherent Anti-Stokes Raman Scattering Spectroscopy Using a Double-Wavelength-Emission Electronically Tuned Ti:Sapphire Laser.

Appl Spectrosc 2021 Aug 10;75(8):988-993. Epub 2021 Jun 10.

School of Biological and Environmental Sciences, Kwansei Gakuen University, Sanda, Japan.

Coherent anti-Stokes Raman scattering (CARS) spectroscopy is a powerful tool for Raman imaging technology. In contrast, conventional spontaneous Raman spectroscopy is often used for biological analysis with multivariate analysis. This study develops a new type of CARS instrument with a double-wavelength-emission, background-free, electronically tuned Ti:sapphire laser (DW-ETL). Read More

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Switchable stimulated Raman scattering microscopy with photochromic vibrational probes.

Nat Commun 2021 05 25;12(1):3089. Epub 2021 May 25.

State Key Laboratory of Surface Physics and Department of Physics, Human Phenome Institute, Multiscale Research Institute of Complex Systems, Academy for Engineering and Technology, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai, China.

Photochromic probes with reversible fluorescence have revolutionized the fields of single molecule spectroscopy and super-resolution microscopy, but lack sufficient chemical specificity. In contrast, Raman probes with stimulated Raman scattering (SRS) microscopy provides superb chemical resolution for super-multiplexed imaging, but are relatively inert. Here we report vibrational photochromism by engineering alkyne tagged diarylethene to realize photo-switchable SRS imaging. Read More

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Digital and analog functionality in monolayer AlOx-based memristors with various oxidizer sources.

Nanotechnology 2021 Jun 8;32(35). Epub 2021 Jun 8.

School of Information Science and Engineering (ISE), Shandong University, Qingdao, People's Republic of China.

Memristors with the outstanding advantages are beneficial for neuromorphic computing and next-generation storage. Realizing various resistive switching behaviors in monolayer memristors is essential for understanding the device physics and fabricating fully memristive devices. In this paper, a simple and feasible method was proposed to achieve the digital and analog resistive switching in Cu/AlOx/Ag memristors by using ozone and water precursors in atomic layer deposition. Read More

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