Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions.Our preliminary results indicated that the quality of emblic medicines might have an apparent region...Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions.Our preliminary results indicated that the quality of emblic medicines might have an apparent regional variation.A rapid and effective geographical traceability system has not been designed yet.To trace the geographical origins so that their quality can be controlled,an integrated spectroscopic strategy including spectral pretreatment,outlier diagnosis,feature selection,data fusion,and machine learning algorithm was proposed.A featured data matrix(245220)was successfully generated,and a carefully adjusted RF machine learning algorithm was utilized to develop the geographical traceability model.The results demonstrate that the proposed strategy is effective and can be generalized.Sensitivity(SEN),specificity(SPE)and accuracy(ACC)of 97.65%,99.85%and 97.63%for the calibrated set,as well as 100.00%predictive efficiency,were obtained using this spectroscopic analysis strategy.Our study has created an integrated analysis process for multiple spectral data,which can achieve a rapid,nondestructive and green quality detection for emblic medicines originating from seventeen geographical origins.展开更多
Amorphous silicon(a-Si) is one of the most promising anode-materials for the lithium-ion battery owing to its large capacity and superior fracture resistance.However,a-Si is usually fabricated with the sophisticated c...Amorphous silicon(a-Si) is one of the most promising anode-materials for the lithium-ion battery owing to its large capacity and superior fracture resistance.However,a-Si is usually fabricated with the sophisticated chemical vapor deposition or pulse laser deposition in a limited scale.In this work,we have succes s fully pre pared a-Si spheres(~200 nm) by reducing the TiO2-coated silica spheres with Al powders in the molten salts at 300℃.The coated TiO2 layer acts as a protective layer for structural maintenance during the reduction and a precursor for doping.The doped Ti element may suppress the crystal growth of Si to facilitate the formation of a-Si.The observation with in-situ transmission electron microscopy(TEM) further reveals that lithiation kinetics of the synthesized a-Si is controlled by the interfacial reaction.The Li^(+) diffusivity in a-Si determined from the observation is in the order of 10^(-14) cm^(2)/s.The anode of a-Si spheres together with crystalline Si nanoparticles exhibits excellent electrochemical performance,delivering a reversible capacity of 1604 mAh/g at 4 A/g and a capacity retention of 78,3%after 500 cycles.The low temperature reduction process reported in this study provides a low-cost method to fabricate a-Si nanostructures as high-capacity durable anode materials.展开更多
基金This work is financially supported by the National Wild Plant Germplasm Resources Infrastructure which is the follow-up work of a project called Standardization and Community for the Collection and Preservation of Important Wild Plant Germplasm Resources(2005DKA21006).
文摘Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions.Our preliminary results indicated that the quality of emblic medicines might have an apparent regional variation.A rapid and effective geographical traceability system has not been designed yet.To trace the geographical origins so that their quality can be controlled,an integrated spectroscopic strategy including spectral pretreatment,outlier diagnosis,feature selection,data fusion,and machine learning algorithm was proposed.A featured data matrix(245220)was successfully generated,and a carefully adjusted RF machine learning algorithm was utilized to develop the geographical traceability model.The results demonstrate that the proposed strategy is effective and can be generalized.Sensitivity(SEN),specificity(SPE)and accuracy(ACC)of 97.65%,99.85%and 97.63%for the calibrated set,as well as 100.00%predictive efficiency,were obtained using this spectroscopic analysis strategy.Our study has created an integrated analysis process for multiple spectral data,which can achieve a rapid,nondestructive and green quality detection for emblic medicines originating from seventeen geographical origins.
基金supported by National Key Research and Development Program of China (No.2017YFA0204600)National Natural Science Foundation of China programs (Nos.U1703128,U1503292)the Hong Kong Polytechnic University (No.1-ZVRP)。
文摘Amorphous silicon(a-Si) is one of the most promising anode-materials for the lithium-ion battery owing to its large capacity and superior fracture resistance.However,a-Si is usually fabricated with the sophisticated chemical vapor deposition or pulse laser deposition in a limited scale.In this work,we have succes s fully pre pared a-Si spheres(~200 nm) by reducing the TiO2-coated silica spheres with Al powders in the molten salts at 300℃.The coated TiO2 layer acts as a protective layer for structural maintenance during the reduction and a precursor for doping.The doped Ti element may suppress the crystal growth of Si to facilitate the formation of a-Si.The observation with in-situ transmission electron microscopy(TEM) further reveals that lithiation kinetics of the synthesized a-Si is controlled by the interfacial reaction.The Li^(+) diffusivity in a-Si determined from the observation is in the order of 10^(-14) cm^(2)/s.The anode of a-Si spheres together with crystalline Si nanoparticles exhibits excellent electrochemical performance,delivering a reversible capacity of 1604 mAh/g at 4 A/g and a capacity retention of 78,3%after 500 cycles.The low temperature reduction process reported in this study provides a low-cost method to fabricate a-Si nanostructures as high-capacity durable anode materials.
