Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the slu...Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the sluggish electrode reaction resulting from its low intrinsic electronic conductivity significantly restricts its electrochemical performance and thus its practical application.Herein,Nb-doped Na_(3)V_(2-x)Nb_(x)(PO_(4))_(2)O_(2)F/graphene(rGO)composites(x=0,0.05,0.1)were prepared using a solvothermal method followed by calcination.Compared to the un-doped NVPOF/r GO,doping V-site with high-valence Nb element(Nb^(5+))(Na_(3)V_(1.95)Nb_(0.05)(PO_(4))_(2)O_(2)F/r GO(NVN05POF/rGO))can result in the generated V4^(+)/V3^(+)mixed-valence,ensuring the lower bandgap and thus the increased intrinsic electronic conductivity.Besides,the expanded lattice space favors the Na^(+)migration.With the structure feature where NVN05POF particles are attached to the rGO sheets,the electrode reaction kinetics is further accelerated owing to the well-constructed electron conductive network.As a consequence,the as-prepared NVN05POF/r GO sample exhibits a high specific capacity of~72 m Ah·g^(-1)at 10C(capacity retention of 65.2%(vs.0.5C))and excellent long-term cycling stability with the capacity fading rate of~0.099%per cycle in 500 cycles at 5C.展开更多
Dear Editor,Breast cancer is now the most frequently diagnosed cancer and is the fifth leading cause of cancer-related death in Chinese women. Therefore, the burden of breast cancer in China is gradually increasing. A...Dear Editor,Breast cancer is now the most frequently diagnosed cancer and is the fifth leading cause of cancer-related death in Chinese women. Therefore, the burden of breast cancer in China is gradually increasing. According to figures released by the Chinese Cancer Center in 2018, the number of newly diagnostic breast cancer is about 278,900 cases, accounting for 16.51%of all women who were diagnosed with the first primary malignant tumors;and 66,000 cases of breast cancer died in 2014 (Chen et al., 2016).展开更多
A new class of iron（II） hydrides based on a tetradentate PSNP ligand were synthesized and fully characterized. All the iron（II） complexes feature a folded PSNP ligand with cis reactive sites. The hydrido iron comp...A new class of iron（II） hydrides based on a tetradentate PSNP ligand were synthesized and fully characterized. All the iron（II） complexes feature a folded PSNP ligand with cis reactive sites. The hydrido iron complex [2 H（NCMe[2_TD$IF]1）]（BF4） is capable of catalyzing aldehyde hydroboration by pinacolborane（HBpin） and with extremely high efficiency at room temperature. Aldehydes with various functional groups are compatible.展开更多
基金supported by the Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities) (No.FRFIDRY-21-023)the Beijing Natural Science Foundation (Nos.2194079 and 2222062)the National Natural Science Foundation of China (Nos.52074023 and 52102205)。
文摘Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the sluggish electrode reaction resulting from its low intrinsic electronic conductivity significantly restricts its electrochemical performance and thus its practical application.Herein,Nb-doped Na_(3)V_(2-x)Nb_(x)(PO_(4))_(2)O_(2)F/graphene(rGO)composites(x=0,0.05,0.1)were prepared using a solvothermal method followed by calcination.Compared to the un-doped NVPOF/r GO,doping V-site with high-valence Nb element(Nb^(5+))(Na_(3)V_(1.95)Nb_(0.05)(PO_(4))_(2)O_(2)F/r GO(NVN05POF/rGO))can result in the generated V4^(+)/V3^(+)mixed-valence,ensuring the lower bandgap and thus the increased intrinsic electronic conductivity.Besides,the expanded lattice space favors the Na^(+)migration.With the structure feature where NVN05POF particles are attached to the rGO sheets,the electrode reaction kinetics is further accelerated owing to the well-constructed electron conductive network.As a consequence,the as-prepared NVN05POF/r GO sample exhibits a high specific capacity of~72 m Ah·g^(-1)at 10C(capacity retention of 65.2%(vs.0.5C))and excellent long-term cycling stability with the capacity fading rate of~0.099%per cycle in 500 cycles at 5C.
基金supported by grants from the National Key Research and Development Program of China(2016YFC1302300)the National Natural Science Foundation of China(81621004,81720108029,81930081,91940305)+3 种基金Guangdong Science and Technology Department(2017B030314026)Clinical Innovation Research Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory(2018GZR0201001)Guangzhou Science Technology and Innovation Commission(201803040015)partly supported by Fountain-Valley Life Sciences Fund of University of Chinese Academy of Sciences Education Foundation。
文摘Dear Editor,Breast cancer is now the most frequently diagnosed cancer and is the fifth leading cause of cancer-related death in Chinese women. Therefore, the burden of breast cancer in China is gradually increasing. According to figures released by the Chinese Cancer Center in 2018, the number of newly diagnostic breast cancer is about 278,900 cases, accounting for 16.51%of all women who were diagnosed with the first primary malignant tumors;and 66,000 cases of breast cancer died in 2014 (Chen et al., 2016).
基金financial support from the "1000 Youth Talents Plan"the National Natural Science Foundation of China (Nos. 21402107, 91427303)the Natural Science Foundation of Shandong Province (Nos. ZR2014M011)
文摘A new class of iron（II） hydrides based on a tetradentate PSNP ligand were synthesized and fully characterized. All the iron（II） complexes feature a folded PSNP ligand with cis reactive sites. The hydrido iron complex [2 H（NCMe[2_TD$IF]1）]（BF4） is capable of catalyzing aldehyde hydroboration by pinacolborane（HBpin） and with extremely high efficiency at room temperature. Aldehydes with various functional groups are compatible.
