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A simple flux-free fusion technique was developed to analyse major and trace element compositions of silicate rocks. The sample powders were melted in a molybdenum capsule sealed in a graphite tube to make a homogenous glass in a temperature-controlled oneatmosphere furnace. The glass was then measured for both major and trace element concentrations by LA-ICP-MS using a calibration strategy of total metal-oxide normalisation. The optimum conditions (i.e., temperature and duration) to make homogeneous glasses were obtained by performing melting experiments using a series of USGS reference materials including BCR-2, BIR-1, BHVO-2, AGV-1, AGV-2, RGM-1, W-2 and GSP-2 with SiO 2 contents from 47 to 73% m/m. Analytical results of the USGS reference materials using our method were generally consistent with the recommended values within a discrepancy of 5-10% for most elements. The routine precision of our method was generally better than 5-10% RSD. Compared with previous methods of LA-ICP-MS whole-rock analyses, our flux-free fusion method is convenient and efficient in making silicate powder into homogeneous glass. Furthermore, it limits contamination and loss of volatile elements during heating. Therefore, our new method has great potential to provide reliable and rapid determinations of major and trace element compositions for silicate rocks.Keywords: LA-ICP-MS, bulk analysis, flux-free fusion, silicate rocks, molybdenum-graphite capsule.Une technique simple de fusion sans flux a et e d evelopp ee pour analyser les compositions en el ements majeurs et traces de roches silicat ees. Les poudres d' echantillons ont et e fondues dans une capsule de molybd ene scell ee dans un tube de graphite pour la production d'un verre homog ene dans un four a une atmosph ere et temp erature contrôl ee. Le verre a ensuite et e mesur e pour les concentrations en el ements majeurs et traces par LA-ICP-MS en utilisant une strat egie de calibration bas ee sur la normalisation totale des oxydes de m etaux. Les conditions optimales (i.e, temp erature et dur ee) pour faire des verres homog enes ont et e obtenues en effectuant des exp eriences de fusion en utilisant une s erie de mat eriaux de r ef erence USGS comprenant BCR-2, BIR-1, BHVO-2, AGV-1, AGV-2, RGM-1, W-2 GSP-2 avec un contenu en SiO 2 compris entre 47 et 73% m/m. Les r esultats de l'analyse des mat eriaux de r ef erence USGS en utilisant notre m ethode sont g en eralement compatibles avec les valeurs recommand ees dans un intervalle de 5 a 10% pour la plupart des el ements. La pr ecision de routine de notre m ethode est g en eralement meilleure que 5-10% RSD. Par rapport aux m ethodes pr ec edentes d'analyse sur roche totale par LA-ICP-MS, notre m ethode de fusion sans flux est pratique et efficace par la production de verres homog enes a partir de poudres de silicate. En outre, elle limite la contamination et la perte d' el ements volatils pendant le chauffage. Par cons equent, notre nouvelle m ethode a un grand potentiel pour fournir des d eterminations fiables et rapides des ...

Iron, Cu and Zn stable isotope systems are applied in constraining a variety of geochemical and environmental processes. Secondary reference materials have been developed by the Institute of Geology, Chinese Academy of Geological Sciences (CAGS), in collaboration with other participating laboratories, comprising three solutions (CAGS-Fe, CAGS-Cu and CAGS-Zn) and one basalt (CAGS-Basalt). These materials exhibit sufficient homogeneity and stability for application in Fe, Cu and Zn isotopic ratio determinations. Reference values were determined by inter-laboratory analytical comparisons involving up to eight participating laboratories employing MC-ICP-MS techniques, based on the unweighted means of submitted results. Isotopic compositions are reported in per mil notation, based on reference materials IRMM-014 for Fe, NIST SRM 976 for Cu and IRMM-3702 for Zn. Respective reference values of CAGS-Fe, CAGS-Cu and CAGS-Zn solutions are as follows: d 56 Fe = 0.83 ± 0.07 and d 57 Fe = 1.20 ± 0.13, d 65 Cu = 0.57 ± 0.06, and d 66 Zn = -0.79 ± 0.12 and d 68 Zn = -1.65 ± 0.24, respectively. Those of CAGS-Basalt are d 56 Fe = 0.15 ± 0.07, d 57 Fe = 0.22 ± 0.10, d 65 Cu = 0.12 ± 0.08, d 66 Zn = 0.17 ± 0.13, and d 68 Zn = 0.34 ± 0.26 (2s).

Three dimensional topological insulators have a thriving application prospect in broadband photodetectors due to the possessed topological quantum states. Herein, a large area and uniform topological insulator bismuth telluride (Bi 2 Te 3 ) layer with high crystalline quality is directly epitaxial grown on GaAs(111)B wafer using a molecular beam epitaxy process, ensuring efficient out-of-plane carriers transportation due to reduced interface defects influence. By tiling monolayer graphene (Gr) on the as-prepared Bi 2 Te 3 layer, a Gr/Bi 2 Te 3 / GaAs heterojunction array prototype was further fabricated, and our photodetector array exhibited the capability of sensing ultrabroad photodetection wavebands from visible (405 nm) to mid-infrared (4.5 μm) with a high specific detectivity (D*) up to 10 12 Jones and a fast response speed at about microseconds at room temperature. The enhanced device performance can be attributed to enhanced light−matter interaction at the high-quality heterointerface of Bi 2 Te 3 /GaAs and improved carrier collection efficiency through graphene as a charge collection medium, indicating an application prospect of topological insulator Bi 2 Te 3 for fast-speed broadband photodetection up to a mid-infrared waveband. This work demonstrated the potential of integrated topological quantum materials with a conventional functional substrate to fabricate the next generation of broadband photodetection devices for uncooled focal plane array or infrared communication systems in future.