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The state of gold in phases of the Cu-Fe-S system:In situ X-ray absorption spectroscopy study

Geoscience Frontiers 2023年第3期14卷 103-116页

作者： Boris R.Tagirov Olga N.Filimonova Alexander l.Trigub Ilya V.Vikentyev Elena V.Kovalchuk Maximilian S.Nickolsky Andrey A.Shiryaev vl.dimir l.reukov Dmitry A.Chareev Institute of Geology of Ore Deposits(IGEM RAS) 35Staromonetnyi per119017 MoscowRussia National Research Centre‘Kurchatov Institute’ 1Akademika Kurchatova pl123182 MoscowRussia Institute of Physical Chemistry and Electrochemistry(IPCE RAS) 31Leninsky Prospect119071 MoscowRussia Institute of Experimental Mineralogy(IEM RAS) 142432 ChernogolovkaMoscow RegionRussia

Chalcopyrite and bornite are the main Au-bearing minerals at Cu porphyry deposits,volcanogenic massive sulfide(VMS)deposits,Cu-Ni deposits of the mafic magmatic complexes,and ores of submarine sulfide *** and intermediate solid solutions with wide compositional variations(bnss and iss–high-temperature chalcopyrite,correspondingly),which can scavenge economic concentrations of Au,appear in the Cu-Fe-S system at ore-forming ***,the state of Au in bnss and iss is yet *** solve this conundrum,we synthesized samples with net chemical composition of bnss and iss,studied them by in situ X–ray absorption spectroscopy(XAS),and used the experimental data to explain the Au distribution among natural ore-forming *** sulfide samples were obtained at 495–700℃ in Au-saturated system by means of salt flux *** bnss contained1.2–1.6 log units more Au than iss:up to 18 wt.%Au in bnss vs 0.4 wt.%Au in iss at 700*** increase of temperature resulted in the sharp increase of Au concentration in both phases,1 log unit per 100℃ at f(S2)close to S_((l)) *** of Au l_(3)-edge spectra recorded at 25–675℃ revealed that at 25℃ Au exists mainly in the metallic *** t>500℃ the spectral features of Audisappear,and “chemically bound”Au *** Au form of occurrence in the iss field is interpreted as Au-bearing clusters with a stromeyerite-like(CuAgS)*** Cu_(2–x)S and bnss contain Au in a mixture of stromeyeritelike and petrovskaite-like(Au_(0.8)Ag_(1.2)S)*** chemical composition of both forms is close to CuAuS,where the nearest Au neighbors are two S atoms at R_(Au-S)=2.34–2.36Å.Results of the present study allow to determine the state of Au and its concentration in the main Cu-bearing minerals of sulfide ores as a function of the T-f(S_(2))-compositional *** to the sharp increase of the CuAuS clusters stability with increasing temperature,in high-temperature ores formed at t>350℃ A

关键词： “Invisible”gold Bornite solid solution Intermediate solid solution Digenite Chalcopyrite X-ray absorption spectroscopy

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Bluetooth<sup>TM</sup>Enabled Acceleration Tracking (BEAT) mHealth System: Validation and Proof of Concept for Real-Time Monitoring of Physical Activity

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E-Health Telecommunication Systems and Networks 2013年第3期2卷 49-57页

作者： Aleksey Shaporev Mathew Gregoski vl.dimir reukov Teresa Kelechi David Morgan Kwartowitz Frank Treiber Alexey Vertegel Bioengineering Department Clemson University Clemson USA College of Nursing Medical University of South Carolina Charleston USA

Physical activity is critical to improve the condition of patients with chronic leg and foot ulcers, especially those who are obese and experienced multiple co-morbid conditions. Unfortunately, these individuals are unable to engage in guideline based physical activity (PA) programs. A prototype of BluetoothTM enabled acceleration tracking (BEAT) mHealth system was developed and manufactured for remote monitoring and stimulation of adherence to PA in deconditioned patients. The system consists of a miniature accelerometer-based sensor, smartphone application, and a network service. Validation testing showed high reliability and reproducibility of the BEAT sensors. Pilot study with human subjects demonstrated high accuracy of the BEAT system in recognition of different exercises and calculating overall outcomes of PA. Taken together, these results indicate that BEAT system could become a valuable tool for realtime monitoring of PA in deconditioned patients.

关键词： mHealth Accelerometer Sensor Physical Activity Monitoring

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