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Laser heating setup for diamond anvil cells for <i>in situ</i> synchrotron and in house high and ultra-high pressure studies
摘要： The diamond anvil cell (DAC) technique combined with laser heating is one of the major methods for studying materials at high pressure and high temperature conditions. In this work, we present a transferable double-sided laser heating setup for DACs with in situ temperature determination. The setup allows precise heating of samples inside a DAC at pressures above 200 GPa and could be combined with synchrotron beamline equipment. It can be applied to X-ray diffraction and X-ray transmission microscopy experiments. In the setup, we use high-magnification and low working distance infinity corrected laser focusing objectives that enable us to decrease the size of the laser beam to less than 5 μm and achieve the maximum optical magnification of 320 times. All optical components of the setup were chosen to minimize chromatic and spatial aberrations for accurate in situ temperature determination by multiwavelength spectroscopy in the 570–830 nm spectral range. Flexible design of our setup allows simple interchange of laser sources and focusing optics for application in different types of studies. The setup was successfully tested in house and at the high-pressure diffraction beamline ID15B at the European Synchrotron Radiation Facility. We demonstrate an example of application of the setup for the high pressure–high temperature powder diffraction study of PdH and X-ray transmission microscopy of platinum at 22(1) GPa as a novel method of melting detection in DACs.
关键词： high pressure,diamond anvil cell,X-ray transmission microscopy,X-ray diffraction,synchrotron,laser heating,high temperature
更新于2025-09-16 10:30:52
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Quasi-statischer MOEMS-Gitterscanner zum spektralen Durchstimmen eines MIR-Quantenkaskadenlasers
摘要： Broadband tuning of MIR-infrared radiation from 3 to 10 μm (1000 to 3200 wavenumbers) is a very promising way for spectroscopic study of gaseous, liquid, or solid species or intermixtures. We report a new quasi-static micro-optical-electrical-mechanic (MOEMS) grating for spectral tuning of an IR light source based on a quantum cascade laser. This concept unites the advantages of broadband sources with the advantages of coherent laser sources in a miniaturized setup. In contrary to resonant MOEMS device, the quasi-static driving principle allows the scanning with arbitrary trajectories and velocity and thus with potential higher spectral resolution. To stabilize the trajectory the MOEMS device is controlled by integrated position sensors. We report the dynamical characteristics of MOEMS micro-mirror with integrated diffraction grating and experimental results of the tuning of a QCL in the wavelength range from 4150 to 4600 nm.
关键词： quantum cascade laser,IR spectroscopy,MOEMS scanner,diffraction grating,micro-mirror
更新于2025-09-16 10:30:52
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Effect of Potassium Nitrate in ZnO Nanoparticle Synthesis to Study the Performance of Dye Sensitized Solar Cell
摘要： X-ray diffraction, Raman investigations, band gap energy of zinc oxide nanoparticles (ZnO NPs) along with current-voltage characteristic curves of an assembled dye-sensitized solar cell (DSSC) are presented in this article. ZnO NPs were first synthesized with and without potassium nitrate (KNO3) salt by precipitation method from precursor solutions of zinc acetate and sodium hydroxide. Then, their thin films were deposited on FTO substrates from the paste made with acetic-acid glacial, and Triton X-100 in ethanol by doctor blade method. The X-ray diffraction (XRD) pattern of ZnO NPs prepared without KNO3 annealed at 500 °C showed a hexagonal wurtzite structure with preferred orientation along (101) planes and crystallite size of 25 nm. Very similar XRD pattern was found for ZnO NPs prepared with KNO3. The crystallite size was found decreased to 17 nm for ZnO NPs made with KNO3 salt. Raman spectrum of ZnO NPs showed the presence of E2 high or E2(2) peak at 437 cm-1. The optical band gaps of the ZnO thin films prepared from ZnO NPs with and without KNO3 were measured to be of 3.16 eV and 3.26 eV, respectively. After sensitizing the above-prepared ZnO films by dye extract of Artocarpus lakoocha, the dye-sensitized solar cells were prepared, and their performance was tested by measuring I-V curves under light illumination of the power density of 1000 W/m2. The measurement showed highest Isc and Voc of 44 μA and 326 mV, respectively.
关键词： Dye-sensitized solar cell,Band gap energy,ZnO nanoparticles,X-ray diffraction,Raman spectrum
更新于2025-09-16 10:30:52
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Pressure effect on optical and structural properties of ZnMnO thin films grown by pulsed laser deposition
摘要： Zn0.95Mn0.05O thin films were deposited on Si substrate by pulsed laser ablation technique under different oxygen pressure. The structural and optical properties of the films were analyzed as a function of the oxygen gas pressure. The Mn concentration and the substrate temperature of the thin films were kept constant at 5 wt% and 200°C respectively. X-ray diffraction technique (XRD), atomic force spectroscopy (AFM), raman spectroscopy and UV-Vis were employed to characterize the optical properties and the crystalline structure of the films. The diffraction patterns revealed that the Mn0.05Zn0.95O thin films were polycrystalline with the wurtzite hexagonal structure of ZnO and highly oriented in c-axis direction, without any secondary phases. The average energy band gap of the films was evaluated around 3.23-3.56 eV. Raman spectrum showed E2 (low) mode of ZnO structure shifted to red and increased its FWHM.
关键词： Laser Ablation,X-ray Diffraction,UV-Vis Spectroscopy,Atomic Force Microscopy,Raman Spectroscopy
更新于2025-09-16 10:30:52
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Identification of cement in atmospheric particulate matter using the hybrid method of laser diffraction analysis and Raman spectroscopy
摘要： The production of cement is associated with the emissions of dust and particulate matter, nitrogen oxides (NOx), sulfur dioxide (SO2), carbon monoxide (CO), heavy metals, and volatile organic compounds into the environment. People living near cement production facilities are potentially exposed to these pollutants, including carcinogens, although at lower doses than the factory workers. In this study we focused on the distribution of fine particulate matter, the composition, size patterns, and spatial distribution of the emissions from Spassk cement plant in Primorsky Krai, Russian Federation. The particulate matter was studied in wash-out from vegetation (conifer needles) using a hybrid method of laser diffraction analysis and Raman spectroscopy. The results showed that fine particulate matter (PM10 fraction) extended to the entire town and its neighbourhood. The percentage of PM10 in different areas of the town and over the course of two seasons ranged from 34.8% to 65% relative to other size fractions of particulate matter. It was further shown that up to 80% of the atmospheric PM content at some sampling points was composed of cement-containing particles. This links the cement production in Spassk-Dalny with overall morbidity of the town population and pollution of the environment.
关键词： Laser diffraction analysis,Atmospheric particulate matter,Ecology,Environmental chemistry,Environmental science,Atmospheric science,Environmental pollution,Raman spectroscopy,PM10
更新于2025-09-16 10:30:52
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Microstructural characterization of Inconel 718 alloy after pulsed laser surface treatment at different powers
摘要： An annealed Inconel 718 alloy was surface-treated by pulsed laser at three different powers (100, 50 and 25 W). Microstructural changes induced by the laser treatments were characterized by use of electron backscatter diffraction and electron channeling contrast imaging techniques. Results show that both annealing twins and strengthening precipitates profusely existing in the as-received specimen are dissolved at elevated temperatures during the laser irradiation. Meanwhile, in the melting zone (MZ), densities of low angle boundaries (LABs) are greatly increased with a large number of Laves phases preferentially distributed along such LABs. For different specimens, widths and depths of their MZs are found to be gradually reduced with decreasing the laser powers. Orientation analyses reveal that the columnar grains in the MZ of the 100 W specimen could inherit orientations existing in the matrix while lower laser powers promote the formation of more nuclei with scattered orientations to grow to be granular grains in the MZ. Hardness tests reveal that the MZs of all laser-treated specimens are softer than the matrix probably due to both precipitate dissolution and grain coarsening.
关键词： pulsed laser surface treatment,hardness,grain boundaries,Inconel 718 alloy,electron backscatter diffraction
更新于2025-09-16 10:30:52
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Effect of heat treatment on the tensile behavior of selective laser melted Ti-6Al-4V by in situ X-ray characterization
摘要： Selective Laser Melted Ti-6Al-4V (as-SLMed) exhibits decreased yield strength, increased work hardening, and increased ductility after heat treatment at 730 °C (HT-730) or 900 °C (HT-900) for 2h. To understand the change of mechanical properties, in situ high energy X-ray diffraction (HEXRD) is used to examine the phase composition, load partitioning, slip system activity, and dislocation density evolution in all three specimens. The as-SLMed specimen is dominated by martensitic α?. After heat treatment, α? partly or fully decomposes into α+β, reducing the yield strength. In HT-730, β precipitates with confined size show much higher lattice strain than the α?/α matrix during deformation; in HT-900, the lattice strain difference is mostly eliminated. This is the main reason for the increased ductility in HT-900. From the lattice strain development, basal slip is identified as the easiest slip system in α?/α. Using an elasto-plastic self-consistent (EPSC) model, the critical resolved shear stress ratio between prismatic slip and basal slip (CRSSprismatic/CRSSbasal) is estimated to be 1.31 and 1.16 in the as-SLMed and the HT-900 specimens, respectively. The α phase in HT-900 is able to activate multiple slip systems and accumulate more dislocations during plastic deformation. This explains why HT-900 has higher work hardening rate than the other two specimens.
关键词： in situ X-ray diffraction,tensile deformation,Ti-6Al-4V,Selective Laser Melting
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - The Role of Detector Position in Quantum Ghost Diffraction
摘要： Quantum ghost diffraction enables the measurement of the spatial diffraction pattern of an object without measuring the spatial distribution of the photons that actually interacted with the object [1]. It uses photon pairs generated e.g. by spontaneous parametric down conversion (SPDC) in a nonlinear optical crystal, and relies on the correlation of the generated signal and idler photons in their spatial and temporal degrees of freedom. This measurement scheme is sketched in Fig. 1 (a). After the source, the two photons are separated into two different paths. The object, here we consider a grating, is located only in the signal path and thus interacts only with the signal photons. To measure the diffraction pattern, two detectors of small cross sections are used in the signal and idler arms. The signal detector is usually at a fixed position, collecting photons that interacted with the object. The idler detector can have varying positions, allowing to spatially resolve the collected photons that never interacted with the object. Through measuring the two-photon coincidence counting rate (cid:1842), there exists the potential for recovering the diffraction pattern of the object, which allows to retrieve the grating period.
关键词： Quantum ghost diffraction,diffraction pattern,spatial correlation,photon pairs
更新于2025-09-12 10:27:22
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Laser method of microscopic sensor synthesis for liquid and gas analysis using glucose and H2S as an example
摘要： Laser-induced deposition of metals from a solution has been used as a new method for the synthesis of microcomposite materials in the copper-silver system. It was shown that the obtained materials have good sensory properties with respect to the determination of D-glucose in aqueous solutions. It is also shown that it can be used for gas sensors. Control of sensory properties can be done by changing the method of deposition. X-ray diffraction, EDX, and impedance spectroscopy were used to characterize the materials obtained and it was shown that laser sequential deposition and coprecipitation of two metals give different results. An explanation of the results was proposed. It explains them by the eutectic nature of the interaction in the copper-silver system.
关键词： copper-silver system,impedance spectroscopy,D-glucose,EDX,sensory properties,X-ray diffraction,Laser-induced deposition,microcomposite materials,gas sensors
更新于2025-09-12 10:27:22
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Operando X-ray diffraction during laser 3D printing
摘要： Laser based additive manufacturing allows to build a designed shape layer-by-layer, offering versatility and flexibility to many metallurgical sectors. The fast cooling rates and repeated heat cycles depending on the laser and scanning parameters are not easily measurable with conventional methods. Thus, advanced predictive computational simulations, required to reduce trial and error lead time, are difficult to validate. A newly developed in operando X-ray diffraction device implemented at a synchrotron beamline, taking advantage of the high brilliance and the fast detectors available, brings the missing link with numerical methods. By performing operando experiments on Ti-6Al-4V with different printing parameters, the temporal evolution of the low and high temperature phases are followed, the heating and cooling rates are measured for the powder and the solid material; and the formation of residual stresses in the b phase is demonstrated. Moreover it is shown that the parameter that has the largest influence on the evolving microstructure is the scanning strategy, introducing a size effect related to the scanning length.
关键词： microstructure evolution,operando X-ray diffraction,scanning strategy,Laser based additive manufacturing,Ti-6Al-4V
更新于2025-09-12 10:27:22