- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Synthesis, characterization and thermoelectric performance of Mg2(Si,Sn,Ge) materials using Si-kerf waste from photovoltaic technology
摘要： The recycling acquisition of silicon waste from photovoltaic industry has gained an increasing attention nowadays, since more than 50% of high purity material ends up as kerf during the wafer cutting process. Currently, different Si-based applications are being exploited in terms of using such Si kerf, in order to lower cost and significantly increase environmental impact. Thermoelectric devices can efficiently contribute towards this recycling approach, via the preparation of highly efficient silicides for power generation. In this work, Bi doped Mg2(Si,Sn,Ge) materials were prepared using Si-kerf originated from photovoltaic (PV) cutting wastes. Different Bi concentrations were studied in terms of thermoelectric properties and performance and a high figure-of-merit of 1.1. was achieved at 800K. In addition, a thorough structural and mechanical property characterization, such as morphology, phase identification, hardness and indentation modulus has been conducted. These results, which were evaluated and compared to materials prepared with pure Si (>99.9%), are presented for the first time for Mg2(Si,Sn,Ge) materials.
关键词： magnesium silicides,thermoelectric figure of merit,mechanical/structural properties,multiphase,silicon,recycling
更新于2025-09-19 17:13:59
-
Characterization of MgO/TiN bilayer deposited on cube-textured copper using pulsed-laser deposition technique
摘要： Here we demonstrate heteroepitaxial growth of MgO/TiN thin films on flexible metal foil of copper substrates using pulsed laser deposition. X-ray and electron diffraction measurements revealed that the epitaxial MgO/TiN bilayer was oriented along (002) direction. The large mismatch between TiN islands and Cu substrate was effectively reduced by the 5/6 and 6/7 variations of domains. Despite the local irregularity of misfit dislocations at TiN/Cu, the domain-matching epitaxy paradigm is a remarkably accurate theory. MgO/TiN bilayer is chemically homogeneous and Mg, Ti, or Cu atoms do not segregate into the low-angle grain boundaries regardless of MgO/TiN films thickness. Thus, it appears that thickness may be reduced up to the value in which TiN fully covers the rough surface of Cu tape. Unfortunately, issues related to the presence of in-plane TiN contraction, probably generated by the difference in thermal expansion coefficient, and the origin of misfit dislocations irregularity at TiN/Cu interface remain unresolved. Our findings can make a substantial contribution to further research on Cu-based coated conductors and help in better understanding the ways that MgO/TiN bilayer are grown on Cu tape.
关键词： titanium nitride,pulsed-laser deposition,magnesium oxide,copper,growth,epitaxy,domain-matching epitaxy
更新于2025-09-19 17:13:59
-
Magnesium-Based Metasurfaces for Dual-Function Switching between Dynamic Holography and Dynamic Color Display
摘要： Metasurface-based color display and holography have greatly advanced the state of the art display technologies. To further enrich the metasurface functionalities, recently a lot of research endeavors have been made to combine these two display functions within a single device. However, so far such metasurfaces have remained static and lack tunability once the devices are fabricated. In this work, we demonstrate a dynamic dual-function metasurface device at visible frequencies. It allows for switching between dynamic holography and dynamic color display, taking advantage of the reversible phase-transition of magnesium through hydrogenation and dehydrogenation. Spatially-arranged stepwise nanocavity pixels are employed to accurately control the amplitude and phase of light, enabling the generation of high-quality color prints and holograms. Our work represents a paradigm towards compact and multifunctional optical elements for future display technologies.
关键词： magnesium,metasurfaces,color display,holography,multifunction
更新于2025-09-19 17:13:59
-
Plasma Diagnostic by Optical Emission Spectroscopy on Dolomite and Cross-Validation Using Scanning Electron Microscopy Coupled with Energy Dispersive X-ray Spectroscopy and Electron Probe Micro-Analysis
摘要： Dolomite [CaMg(CO3)2] is an important carbonate mineral mainly composed of calcium magnesium carbonate. The correct determination of magnesium content in carbonate rocks is important for accessing its suitability for different applications; however, presence of different phases with varying magnesium contents makes their analysis difficult. In the present work, a natural carbonate mineral dolomite is analyzed qualitatively and quantitatively using laser-induced breakdown spectroscopy along with X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy and electron-probe microanalysis. The optical emission spectra recorded in 200–720 nm wavelength region revealed presence of emission lines for Ca, Mg, Al, Sr, and Na with varying intensities. We used two different techniques, that is, Boltzmann plot and Saha–Boltzmann plot methods to calculate the plasma temperature, and an average value of 4500 ± 450 K was deduced.The Stark broadening line profile method was exploited to calculate the electron number density using calcium and magnesium lines which resulted in 2.39 × 1017 cm–3. The quantitative compositional analysis was carried out using calibration-free laser-induced breakdown spectroscopy method for which the local thermodynamic equilibrium and optically thin plasma conditions were satisfied.The composition for dolomite major constituents calcium and magnesium were estimated as 68.58 and 31.41%, respectively.The results demonstrated the LIBS, EDS, and EPMA ability as an effective, powerful and complementary analytical techniques for the elemental composition analysis of carbonate minerals.
关键词： magnesium,calibration-free laser-induced breakdown spectroscopy,EPMA,plasma diagnostic techniques,dolomite,EDS
更新于2025-09-19 17:13:59
-
The New Heat Source Model of AZ31B Magnesium Alloy Laser-TIG Hybrid Welding
摘要： A new heat source model consisted of inverted conical heat source and rotary Gauss body heat source is established using the CAE software for the keyhole effect of laser-TIG hybrid welding. The inverted conical heat source is used for analyzing the wide upper part of weld pool due to the rapid heat up by the laser and arc. The rotary Gauss body heat source model is used for analyzing the long and narrow lower part of weld pool formed by the laser. The result showed that, compared with other single source mode, this new heat source model may get a better simulation of the weld pool morphology, especially the inflection point near the keyhole. It provides a new method to predict the morphology and size of the weld pool of magnesium alloy laser-TIG welding.
关键词： shape of weld molten,keyhole effect,magnesium alloy,laser-TIG hybrid welding
更新于2025-09-16 10:30:52
-
Distarch Phosphate as a Matrix for the Generation of Quantum Dots
摘要： Generation of ZnS, CdS, CaS and MgS quantum dots (QDs) was attempted in the matrix of distarch phosphate, an anionic polysaccharide. Based on the analysis of FTIR spectra, thermograms and Differential Scanning Calorimetry, interactions of QDS with the matrix could be excluded. On generation of MgS QDs and also, to a certain extent, CaS QDs, hydrolysis of the salts generating these QDs took place. That process had an impact on the partial destruction of the matrix. Molecular weight and radii of gyration of the products showed that the generation of QDs was dependent on the properties of the matrix polysaccharide. The elasticity, plasticity and viscosity of the gels containing QDs were significantly lower than those of plain distarch phosphate. Generally these values changed with time similarly to gels free of QDs.
关键词： Biocomposites,Calcium sulfide,Cadmium sulfide,Magnesium sulfide,Zinc sulfide,Luminescent biodegradable foils
更新于2025-09-16 10:30:52
-
High-yielding Pd <sub/>2</sub> (dba) <sub/>3</sub> ·C <sub/>6</sub> H <sub/>6</sub> -based four-fold Sonogashira coupling with selenophene-conjugated magnesium tetraethynylporphyrin for organic solar cells
摘要： A catalytic system using Pd2(dba)3$(C6H6)/PPh3/CuI for Sonogashira coupling was demonstrated to synthesize a selenophene-conjugated magnesium tetraethynylporphyrin Mg-TEP-(Se-DPP)4 (2a). The terminal alkynes of magnesium tetraethynylporphyrin with bromoselenophene-tethered diketopyrrolopyrroles (DPPs) to produce the desired star-shaped 2a in 80% yield. This molecule shows higher solubility in organic solvents, more efficient visible and near-infrared region absorption, and a narrower band gap compared with reference thiophene-conjugated congeners. Two strategies, namely, selenium substitution and end-capping, were investigated to optimize bulk heterojunction structures in the active layers of organic solar cells. The optimized device based on 2a:PC61BM exhibited the highest PCE of 6.09% among the tested devices after solvent vapor annealing, owing to efficient exciton dissociation, balanced carrier mobility, and suppressed carrier recombination in the film's ordered morphology.
关键词： end-capping,selenium substitution,Sonogashira coupling,selenophene-conjugated magnesium tetraethynylporphyrin,organic solar cells
更新于2025-09-16 10:30:52
-
Application of acoustic emission and laser optoacoustics at various stages of defect formation during friction stir welding
摘要： This paper covers basic aspects of laser ultrasound and acoustic emission non-destructive testing methods in application of monitoring friction stir welds during its deformation and fracture. Stress-strain curves for such welds were obtained and the mechanical characteristics of welded joints of aluminum-magnesium alloy were determined. Using acoustic elastic effect levels of mechanical stresses were measured. Signals of acoustic emission, stimulated by one-axis loading, were registered and analyzed. It was established that acoustic emission during deformation and fracture of samples of welded joints is associated with the course of the process of plastic flow of the material. The nature of the distribution of acoustic emission parameters in the destruction of welded joints with defects has distinctive features. In conditions of one axis quasi static loading rate event count acoustic emission is the most informative parameter.
关键词： friction stir welding,laser optoacoustics,aluminum-magnesium alloy,acoustic emission,defect formation
更新于2025-09-16 10:30:52
-
Computer aided design of the laser dieless drawing process of tubes from magnesium alloy with take into account ductility of the material
摘要： Paper is devoted to the laser dieless drawing of the tubes made of magnesium alloy ZEK100. Important limitation of this process is a low ductility of magnesium alloys. The purpose of this work was the development and implementation into the FEM code, the ductility model of ZEK100 magnesium alloy and experimental validation of proposed methodology of process design. Ductility and flow stress models were developed based on tension and compression tests in temperature interval 20-350 °C. As result of this work, the technological diagrams for determination of diameter of tube after laser dieless drawing process were obtained.
关键词： Ductility,Dieless drawing,Tube,Magnesium alloys
更新于2025-09-12 10:27:22
-
Optimization of production process of Mg tubes produced with laser dieless drawing method and related microstructural analysis
摘要： This contribution deals with a laser dieless drawing method in which tubes (AZ31 magnesium alloy) with small dimensions are produced from previously extruded tubes with a larger diameter. The process involves local laser heating of a tube with concurrent drawing and rotation of a sample. The control parameters need to be optimized in order to get a good quality tube with low damage and regular diameter. Here, a previously developed finite element (FE) model is used for the numerical optimization. The optimization itself is multi-objective, maximizing the uniformity of the resulting tube but concurrently, minimizing its critical deformation. Since one run of the FE code lasts for several days, an approximation by a Radial Basis Function meta-model (surrogate) is used. Results reveal that there is only a very limited number of combinations of parameters leading to a uniformly shaped tubes. Finally, tubes produced with optimized parameters are analyzed from the microstructural point of view.
关键词： Laser dieless drawing process,Microstructural analysis,Optimization,Numerical modeling,Magnesium alloys
更新于2025-09-12 10:27:22