Interlayer antiferromagnetic coupling,small magnetic anisotropy,and low air stability of the intrinsic magnetic topological insulator MnBi_(2)Te_(4)have been critical bottlenecks to the future application of the quant...Interlayer antiferromagnetic coupling,small magnetic anisotropy,and low air stability of the intrinsic magnetic topological insulator MnBi_(2)Te_(4)have been critical bottlenecks to the future application of the quantum anomalous Hall efect(QAHE)at zero magnetic feld.In this study,we propose a scheme to utilize capped sliding van der Waals materials to efectively modulate the magnetic and topological properties of MnBi_(2)Te_(4).Our results demonstrate that the h-BN/MnBi_(2)Te_(4)/h-BN heterostructure,constructed by sliding ferroelectric h-BN bilayer and MnBi_(2)Te_(4),not only realizes a transition from interlayer antiferromagnetic to ferromagnetic coupling but also signifcantly enhances the out-of-plane magnetism and air stability of MnBi_(2)Te_(4).Moreover,the above magnetic properties can be further improved by tuning the interlayer distance between h-BN and MnBi_(2)Te_(4).Additionally,the obtained band structures and topological properties clearly support that the h-BN/MnBi_(2)Te_(4)/hBN heterostructure can harbor the QAHE with a Chern number of C=1.This work provides a new and nonvolatile modulation approach to achieve high-temperature and high-precision QAHE at zero magnetic feld.展开更多
DEAR EDITOR, The distribution of the capped langur （Trachypithecus pileatus） in China has become controversial since Shortridge＇s langur （Trachypithecus shortridgei） was upgraded to a full species. The capped lan...DEAR EDITOR, The distribution of the capped langur （Trachypithecus pileatus） in China has become controversial since Shortridge＇s langur （Trachypithecus shortridgei） was upgraded to a full species. The capped langur is considered to be distributed in northeast India, Bangladesh, Bhutan, and northwest Myanmar only （Brandon-Jones et al., 2004; Choudhury, 2008, 2014; Das et al., 2008; Groves, 2001）. In our field survey, however, we obtained photos of the capped langur, demonstrating its existence in China. Following the species promotion of Shortridge＇s langur （Brandon-Jones et al., 2004; Groves, 2001） and the delimiting of its distribution range to northwestern Yunnan in China and northeastern Myanmar （Brandon-Jones et al., 2004; Cui et al.,展开更多
With _D-proline as the reducing and capping agent, fluorescent gold nanoclusters were rapidly prepared(_D-Pro@AuNCs) within 10 min at 100℃. In the present of gold nanoparticles, the fluorescence of _DPro@AuNCs was re...With _D-proline as the reducing and capping agent, fluorescent gold nanoclusters were rapidly prepared(_D-Pro@AuNCs) within 10 min at 100℃. In the present of gold nanoparticles, the fluorescence of _DPro@AuNCs was remarkably quenched. Interestingly, based on the electrostatic interaction between anticancer drug Raltitrexed and gold nanoparticles induced fluorescence "turn-on" principle, a high selective assay for detection of Raltitrexed was established with the probe associating the fluorescence emission at 435 nm. The fluorescence intensity of _D-Pro@AuNCs linearly correlated with the concentration of Raltitrexed in the range from 5.0 mmol/L to 40.0 mmol/L(R^2= 0.999) and the limit of detection was 1.9 mmol/L. Further, after Raltitrexed was abdominal injected in rats, a metabolic approach was constructed with the prepared fluorescent probe. It showed great potential of AuNCs-based sensing probes for application in analysis of serum anticancer drugs.展开更多
Hydrothermal reactions of Na2MoO2·2H2O and NH4VO3（or V2O5） with appropriate reducing agents such as organic amines, NH2OH·HCl and Mo（CO）6 gave rise to the formation of a series of capped Keggin derivativ...Hydrothermal reactions of Na2MoO2·2H2O and NH4VO3（or V2O5） with appropriate reducing agents such as organic amines, NH2OH·HCl and Mo（CO）6 gave rise to the formation of a series of capped Keggin derivatives, [N（CH3）4]2Na3（NH4）2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·-13H2O（1）, [NH4]7[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·7H2O（2）, [HN（CH2CH2）3NH][（PO4）Mo^V3Mo^VI9O36（V^IVO）2]·-3[N（CH2CH2）3N]·（en）·4.5H2O（3） and [HNH2OH][NH4]2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）4]·24H2O（4）. Single-crystal X-ray diffraction analysis revealed that the anions in 1-3 are two-capped Keggin derivatives with characteristic trans vanadium-oxygen caps, whereas the heteropoly anion in 4 is a tetra-capped α-Keggin derivative with characteristic vanadium-oxygen caps on the equatorial plane.展开更多
Tin monosulphide(SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath depo...Tin monosulphide(SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath deposition(CBD) at different bath temperatures varying in the range, 50–80 °C. X–ray diffraction analysis showed that the deposited films were polycrystalline in nature, showing orthorhombic structure with an intense peak corresponding to(040) plane of SnS. These observations were further confirmed by Raman analysis. FTIR spectra showed the absorption bands which corresponds to PVA in addition to SnS.The scanning electron microscopy and atomic force microscopy studies revealed that the deposited SnS films were uniform and nanostructured with an average particle size of 4.9 to 7.6 nm. The optical investigations showed that the layers were highly absorbing with the optical absorption coefficient ～10~5 cm^(-1). A decrease in optical band gap from 1.92 to 1.55 eV with an increase of bath temperature was observed. The observed band gap values were higher than the bulk value of 1.3 eV, which might be due to quantum confinement effect. The optical band gap values were also used to calculate particle size and the results are discussed.展开更多
Dodecylbenzenesulfonate (DBS)-capped TiO2 nanoparticles have been synthesized and employed in dye-sensitized solar cells to form a quasi-solid state electrolyte. Owing to the long alkyl-chain capping around the TiO2 n...Dodecylbenzenesulfonate (DBS)-capped TiO2 nanoparticles have been synthesized and employed in dye-sensitized solar cells to form a quasi-solid state electrolyte. Owing to the long alkyl-chain capping around the TiO2 nanoparticles interacting with the liquid solvent, the dye sensitized solar cell based on such DBS-capped TiO2 nanoparticle framework material gel electrolyte shows higher stability compared with the non-capped one in the long-term application and gives a comparable overall efficiency of 6.3% at AM 1.5 illumination.展开更多
Silver nanoparticles(AgNPs)are of potential interest because of their effective antibacterial and antiviral activities.Capping agents are used for exhibiting a better antibacterial activity than uncapped Ag NPs.There ...Silver nanoparticles(AgNPs)are of potential interest because of their effective antibacterial and antiviral activities.Capping agents are used for exhibiting a better antibacterial activity than uncapped Ag NPs.There are very few reports that have shown the usage of AgNPs for in-vivo antibacterial therapy.Citrate-capped silver nanoparticles were synthesized chemically by citrate reduction method;the size of Cit-AgNPs was determined by an atomic force microscope(AFM)and was between 15-90 nm.Acinetobacter baumannii(A.baumannii)isolates were the only sensitive species to Cit-AgNPs.MICs and MBC of Cit-AgNPs were determined by using A.baumannii.The results showed an additive effect of Cit-AgNPs.Four mice groups were infected with a sub-lethal dose of A.baumannii intraperitoneally,IP.The single daily dose of Cit-AgNPs and imipenem plus Cit-AgNPs combination were administered IP.Imipenem and phosphate buffer saline(PBS)was used as positive control and negative control,respectively.Interestingly,only the PBS-treated group showed growth of A.baumannii in the liver and spleen of sacrificed mice.Histopathologically,Cit-AgNPs showed antibacterial activity and had an additive effect when combined with imipenem in vivo and in vitro.Moreover,the Cit-AgNPs showed dose-dependent activity and the organs differed in the illumination of the toxicity effect of Cit-AgNPs even after high dose administration.In conclusion,Cit-capped AgNPs had antibacterial activity against multiple drug resistant(MDR)A.baumannii but not against K.pneumoniae and E.coli.Cit-capped AgNPs increased the inhibition zone of imipenem in additive effect;the minimum inhibitory concentration and the minimum bactericidal concentration of Cit-capped AgNPs were relatively low.Cit-capped AgNPs eliminated A.baumannii infection in vivo when it was given alone or in combination with imipenem.The cytotoxicity of Cit-AgNPs was dose-dependent and the organs differed in the illumination of the inflammatory effect of Cit-AgNPs after high dose administration.It is not recommended to use Cit-capped AgNPs systemically despite their valuable additive antibacterial effect especially with a high dose and the combination with imipenem,Topical administration needs to be evaluated.展开更多
Copolymers of 9,9-dioctylfluorene(DOF)and 2-thienyl-benzothiadiazole(DBT)were synthesized by Suzuki reaction and end-capped by N-hexyl-carbazole and benzene,which were abbreviated as PDOF-DBT-Cz and PDOF-DBT-B,respect...Copolymers of 9,9-dioctylfluorene(DOF)and 2-thienyl-benzothiadiazole(DBT)were synthesized by Suzuki reaction and end-capped by N-hexyl-carbazole and benzene,which were abbreviated as PDOF-DBT-Cz and PDOF-DBT-B,respectively.The photophysical,electrochemical and thermal properties of the copolymers were studied.The results indicated that replacement of N-hexyl-carbazole as end-capping group of PDOF-DBT can vary light color and improve luminescence efficiency.展开更多
基金supported by the National Key R&D Program of China(Grant No.2024YFA1408103)National Natural Science Foundation of China(Grants No.11974098,12474158,12234017 and 12488101)+3 种基金Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302800)Natural Science Foundation of Hebei Province(Grant No.A202305017)Anhui Initiative in Quantum Information Technologies(Grant No.AHY170000)Fundamental Research Funds for the Central Universities(Grant No.WK2340000082)。
文摘Interlayer antiferromagnetic coupling,small magnetic anisotropy,and low air stability of the intrinsic magnetic topological insulator MnBi_(2)Te_(4)have been critical bottlenecks to the future application of the quantum anomalous Hall efect(QAHE)at zero magnetic feld.In this study,we propose a scheme to utilize capped sliding van der Waals materials to efectively modulate the magnetic and topological properties of MnBi_(2)Te_(4).Our results demonstrate that the h-BN/MnBi_(2)Te_(4)/h-BN heterostructure,constructed by sliding ferroelectric h-BN bilayer and MnBi_(2)Te_(4),not only realizes a transition from interlayer antiferromagnetic to ferromagnetic coupling but also signifcantly enhances the out-of-plane magnetism and air stability of MnBi_(2)Te_(4).Moreover,the above magnetic properties can be further improved by tuning the interlayer distance between h-BN and MnBi_(2)Te_(4).Additionally,the obtained band structures and topological properties clearly support that the h-BN/MnBi_(2)Te_(4)/hBN heterostructure can harbor the QAHE with a Chern number of C=1.This work provides a new and nonvolatile modulation approach to achieve high-temperature and high-precision QAHE at zero magnetic feld.
基金supported by the Second National Survey of Terrestrial Wildlife Resources of the State Forestry Administration of China(Semnopithecus schistaceus Project,No.176 Geographic Unit Project)the National Natural Science Foundation of China(31400361)+1 种基金the Science and Technology Planning Project of Guangdong Province,China(2013B061800042)the National Key Program(2016YFC0503200)from the Ministry of Science and Technology of China
文摘DEAR EDITOR, The distribution of the capped langur （Trachypithecus pileatus） in China has become controversial since Shortridge＇s langur （Trachypithecus shortridgei） was upgraded to a full species. The capped langur is considered to be distributed in northeast India, Bangladesh, Bhutan, and northwest Myanmar only （Brandon-Jones et al., 2004; Choudhury, 2008, 2014; Das et al., 2008; Groves, 2001）. In our field survey, however, we obtained photos of the capped langur, demonstrating its existence in China. Following the species promotion of Shortridge＇s langur （Brandon-Jones et al., 2004; Groves, 2001） and the delimiting of its distribution range to northwestern Yunnan in China and northeastern Myanmar （Brandon-Jones et al., 2004; Cui et al.,
基金the financial support from the National Natural Science Foundation of China (Nos. 21575144, 91732103, 21874138, 21635008, 21621062)
文摘With _D-proline as the reducing and capping agent, fluorescent gold nanoclusters were rapidly prepared(_D-Pro@AuNCs) within 10 min at 100℃. In the present of gold nanoparticles, the fluorescence of _DPro@AuNCs was remarkably quenched. Interestingly, based on the electrostatic interaction between anticancer drug Raltitrexed and gold nanoparticles induced fluorescence "turn-on" principle, a high selective assay for detection of Raltitrexed was established with the probe associating the fluorescence emission at 435 nm. The fluorescence intensity of _D-Pro@AuNCs linearly correlated with the concentration of Raltitrexed in the range from 5.0 mmol/L to 40.0 mmol/L(R^2= 0.999) and the limit of detection was 1.9 mmol/L. Further, after Raltitrexed was abdominal injected in rats, a metabolic approach was constructed with the prepared fluorescent probe. It showed great potential of AuNCs-based sensing probes for application in analysis of serum anticancer drugs.
基金Supported by the 973 key program of the MOST(2010CB933501,2012CB821705)the Chinese Academy of Sciences(KJCX2-YW-319,KJCX2-EW-H01)+1 种基金the National Natural Science Foundation of China(21373221,21221001,91022008,91122027,51172232)the Natural Science Foundation of Fujian Province(2011HZ0001-1,2012J06006,2006L2005)
文摘Hydrothermal reactions of Na2MoO2·2H2O and NH4VO3（or V2O5） with appropriate reducing agents such as organic amines, NH2OH·HCl and Mo（CO）6 gave rise to the formation of a series of capped Keggin derivatives, [N（CH3）4]2Na3（NH4）2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·-13H2O（1）, [NH4]7[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·7H2O（2）, [HN（CH2CH2）3NH][（PO4）Mo^V3Mo^VI9O36（V^IVO）2]·-3[N（CH2CH2）3N]·（en）·4.5H2O（3） and [HNH2OH][NH4]2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）4]·24H2O（4）. Single-crystal X-ray diffraction analysis revealed that the anions in 1-3 are two-capped Keggin derivatives with characteristic trans vanadium-oxygen caps, whereas the heteropoly anion in 4 is a tetra-capped α-Keggin derivative with characteristic vanadium-oxygen caps on the equatorial plane.
文摘Tin monosulphide(SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath deposition(CBD) at different bath temperatures varying in the range, 50–80 °C. X–ray diffraction analysis showed that the deposited films were polycrystalline in nature, showing orthorhombic structure with an intense peak corresponding to(040) plane of SnS. These observations were further confirmed by Raman analysis. FTIR spectra showed the absorption bands which corresponds to PVA in addition to SnS.The scanning electron microscopy and atomic force microscopy studies revealed that the deposited SnS films were uniform and nanostructured with an average particle size of 4.9 to 7.6 nm. The optical investigations showed that the layers were highly absorbing with the optical absorption coefficient ～10~5 cm^(-1). A decrease in optical band gap from 1.92 to 1.55 eV with an increase of bath temperature was observed. The observed band gap values were higher than the bulk value of 1.3 eV, which might be due to quantum confinement effect. The optical band gap values were also used to calculate particle size and the results are discussed.
基金Project supported by the State Key Program of Fundamental Research (No. G1998061308) the National High Technology Research Development Plan of China (Nos. 2002 AA 302403 and 0216nm040) and the National Natural Science Foundation of China (No. 20221101)
文摘Dodecylbenzenesulfonate (DBS)-capped TiO2 nanoparticles have been synthesized and employed in dye-sensitized solar cells to form a quasi-solid state electrolyte. Owing to the long alkyl-chain capping around the TiO2 nanoparticles interacting with the liquid solvent, the dye sensitized solar cell based on such DBS-capped TiO2 nanoparticle framework material gel electrolyte shows higher stability compared with the non-capped one in the long-term application and gives a comparable overall efficiency of 6.3% at AM 1.5 illumination.
文摘Silver nanoparticles(AgNPs)are of potential interest because of their effective antibacterial and antiviral activities.Capping agents are used for exhibiting a better antibacterial activity than uncapped Ag NPs.There are very few reports that have shown the usage of AgNPs for in-vivo antibacterial therapy.Citrate-capped silver nanoparticles were synthesized chemically by citrate reduction method;the size of Cit-AgNPs was determined by an atomic force microscope(AFM)and was between 15-90 nm.Acinetobacter baumannii(A.baumannii)isolates were the only sensitive species to Cit-AgNPs.MICs and MBC of Cit-AgNPs were determined by using A.baumannii.The results showed an additive effect of Cit-AgNPs.Four mice groups were infected with a sub-lethal dose of A.baumannii intraperitoneally,IP.The single daily dose of Cit-AgNPs and imipenem plus Cit-AgNPs combination were administered IP.Imipenem and phosphate buffer saline(PBS)was used as positive control and negative control,respectively.Interestingly,only the PBS-treated group showed growth of A.baumannii in the liver and spleen of sacrificed mice.Histopathologically,Cit-AgNPs showed antibacterial activity and had an additive effect when combined with imipenem in vivo and in vitro.Moreover,the Cit-AgNPs showed dose-dependent activity and the organs differed in the illumination of the toxicity effect of Cit-AgNPs even after high dose administration.In conclusion,Cit-capped AgNPs had antibacterial activity against multiple drug resistant(MDR)A.baumannii but not against K.pneumoniae and E.coli.Cit-capped AgNPs increased the inhibition zone of imipenem in additive effect;the minimum inhibitory concentration and the minimum bactericidal concentration of Cit-capped AgNPs were relatively low.Cit-capped AgNPs eliminated A.baumannii infection in vivo when it was given alone or in combination with imipenem.The cytotoxicity of Cit-AgNPs was dose-dependent and the organs differed in the illumination of the inflammatory effect of Cit-AgNPs after high dose administration.It is not recommended to use Cit-capped AgNPs systemically despite their valuable additive antibacterial effect especially with a high dose and the combination with imipenem,Topical administration needs to be evaluated.
基金Supported by the Major Project of Science Foundation Ministry of Education of China(Grant No.207015)the National Natural Science Foundation of China(Grant No.20671068)
文摘Copolymers of 9,9-dioctylfluorene(DOF)and 2-thienyl-benzothiadiazole(DBT)were synthesized by Suzuki reaction and end-capped by N-hexyl-carbazole and benzene,which were abbreviated as PDOF-DBT-Cz and PDOF-DBT-B,respectively.The photophysical,electrochemical and thermal properties of the copolymers were studied.The results indicated that replacement of N-hexyl-carbazole as end-capping group of PDOF-DBT can vary light color and improve luminescence efficiency.
