Wide potential windows were found at carbon nanotube film electrodes in neutral solutions after being treated with nitric acid and mixed acid. Electrochemical reversibility was investigated at carbon nanotube films wi...Wide potential windows were found at carbon nanotube film electrodes in neutral solutions after being treated with nitric acid and mixed acid. Electrochemical reversibility was investigated at carbon nanotube films with different pretreatments for ferri/ferrocyanide and quinone /hydroquinone. Carbon nanotube film electrodes presented quasi-reversible electrochemical behavior for both electrolytes. In the range of scan rate, carbon nanotube film electrodes treated with acids showed heterogeneous electron-transfer properties, which was mainly controlled by its electron state density on the surface of the film. On the whole, the carbon nanotube electrode with nitric acid treatment presented the best electrochemical behaviors, so we chose it as an analytical electrode to determine the trace compound in dilute solution. The results demonstrated that this new electrode material exhibits superior performance characteristics for the detection of azide anion.展开更多
By using both DV-Xα and EH-CO methods, the calculation studies of the structure-property relationships of a series of metal azides, of their clusters’ electronic structures in ground and excited states, of their sys...By using both DV-Xα and EH-CO methods, the calculation studies of the structure-property relationships of a series of metal azides, of their clusters’ electronic structures in ground and excited states, of their systems with cation vacancy and the doped Pb(N3)2, as well as their crystal band structures have been conducted. The results show that the sensitivity of ionic-type metal azides varies with the degree of difficulty of electronic transition of the losing charge on N3. A metal azide with cation vacancies has a greater sensitivity than the perfect one. When doped with monovalent metal ions, lead azide’s sensitivity increased; when with trivalent ones, its sensitivity decreased; when with divalent ones, little of it changed. Compared with heavy metal azides. an alkali metal azide has a larger band gap, a smaller band width and a greater transition energy of frontier electron with a smaller amount of losing charge on N3, and thus has lower sensitivity and conductivity than heavy metal azides.展开更多
The great achievements of click chemistry have encouraged polymer scientists to use this reaction in their field. This review assembles an update of the advances of using azide-alkyne click polymerization to prepare f...The great achievements of click chemistry have encouraged polymer scientists to use this reaction in their field. This review assembles an update of the advances of using azide-alkyne click polymerization to prepare functional polytriazoles（PTAs） with linear and hyperbranched structures.The Cu（I）-mediated click polymerization furnishes 1,4-regioregular PTAs,whereas,the metal-free click polymerization of propiolates and azides produces PTAs with 1,4-regioisomer contents up to 90%.The PTAs display advanced functions,such as aggregation-induced emission,thermal stability,biocompatibility and optical nonlinearity.展开更多
Field and pot experiments were conducted using indica rice varieties with differential chalkiness. There were significant differences in root activity among the varieties. The percentages of chalky grains and chalky a...Field and pot experiments were conducted using indica rice varieties with differential chalkiness. There were significant differences in root activity among the varieties. The percentages of chalky grains and chalky area were both negatively correlated with root activity expressed as α-naphthylamine oxidation ability （RA） per gram of fresh root （RAfw） , RA per spikelet （RAgrn）, or RA per sink capacity （RAsink）. The RAsink was more closely related to chalkiness than RAt, and RAgrn when varieties differed greatly in panicle size and grain weight. Application of NO3^--N fertilizer at heading resulted in higher root activity and reduced chalkiness. Application of 30 mg/L NaN3 （respiration inhibitor） resulted in reduced root activity and increased chalkiness for one variety ＇GD9501＇, but for the other variety ＇Qinluai＇ was in reverse. The percentages of chalky grains and chalky area were negatively correlated with root activity at 10 days after heading under different chemical treatments （r=-0.8567^＊ and r=-0.9211^＊＊, respectively）.展开更多
The high-pressure structure and elastic properties of calcium azide(Ca(N_(3))_(2))were investigated using in-situ highpressure x-ray diffraction and Raman scattering up to 54 GPa and 19 GPa,respectively.The compressib...The high-pressure structure and elastic properties of calcium azide(Ca(N_(3))_(2))were investigated using in-situ highpressure x-ray diffraction and Raman scattering up to 54 GPa and 19 GPa,respectively.The compressibility of Ca(N_(3))_(2)changed as the pressure increased,and no phase transition occurred within the pressure from ambient pressure up to 54 GPa.The measured zero-pressure bulk modulus of Ca(N_(3))_(2)is higher than that of other alkali metal azides,due to differences in the ionic character of their metal-azide bonds.Using CASTEP,all vibration modes of Ca(N_(3))_(2)were accurately identified in the vibrational spectrum at ambient pressure.In the high-pressure vibration study,several external modes(ext.)and internal bending modes(ν_(2))of azide anions(N_(3)^(-))softened up to~7 GPa and then hardened beyond that pressure.This evidence is consistent with the variation observed in the F_(E)–f_(E)data analyzed from the XRD result,where the slope of the curve changes at 7.1 GPa.The main behaviors under pressure are the alternating compression,rotation,and bending of N_(3)^(-)ions.The bending behavior makes the structure of Ca(N_(3))_(2)more stable under pressure.展开更多
The random copolymers grafted onto the surfaces of SiO2 hollow sphere via reverse atom transfer radical polymerization （RATRP） and ＂click＂ chemistry were investigated. A sufficient amount of peroxides, as initiati...The random copolymers grafted onto the surfaces of SiO2 hollow sphere via reverse atom transfer radical polymerization （RATRP） and ＂click＂ chemistry were investigated. A sufficient amount of peroxides, as initiating moieties, were introduced onto the surface of hollow spheres. Then styrene and 4-vinylbenzyl azide were polymerized via surface-initiated reverse atom transfer radical polymerization （SI-RATRP） using the peroxide group modified hollow sphere as initiator, resulting in hollow spheres （HS） with grafted polystyrene-co-poly（4-vinylbenzyl azide） copolymer brushes as （HS-g-PS-co-PVBA） intermedi- ate material. Subsequently, N-propargyl-carbazole （PC） was covalently bonded to HS-g-PS-co-PVBA by the ＂click＂ reaction, resulting in the HS-g-PS-co-PVBPC hybrid material. The excitation spectrum is dominated by a broad band from 350 nm to 400 nm with the maximum peak at 362 nm, attributed to the characteristic absorption of the carbazole grouD of HS-g-PS-co-PVBPC hybrid material.展开更多
A new coordination complex, [Ag(IIMB)N 3], was prepared by self-assembly of asymmetric ligand 1-(1-imidazolyl)-4-(imidazol-1-ylmethyl)benzene(IIMB) with [Ag(NH 3) 2]N 3. The crystal structural analysis indicates that ...A new coordination complex, [Ag(IIMB)N 3], was prepared by self-assembly of asymmetric ligand 1-(1-imidazolyl)-4-(imidazol-1-ylmethyl)benzene(IIMB) with [Ag(NH 3) 2]N 3. The crystal structural analysis indicates that the structure of the complex contains fifty-two-membered macrometallacyclic rings, and the complex crystallizes in monoclinic system, space group of P2 1/c with a=0.739 8(1) nm, {b=}1.045 1(1) nm, c=1.812 4(2)nm, β=91.65(1)°, V=1.400 7(3) nm3, Z=4, D c=1.774 g/cm3, {F(000)=}744, R=0.050 5, wR=0.084 0. It is notable that the azide ion bridges two silver(Ⅰ) atoms in end-on fashion.展开更多
文摘Wide potential windows were found at carbon nanotube film electrodes in neutral solutions after being treated with nitric acid and mixed acid. Electrochemical reversibility was investigated at carbon nanotube films with different pretreatments for ferri/ferrocyanide and quinone /hydroquinone. Carbon nanotube film electrodes presented quasi-reversible electrochemical behavior for both electrolytes. In the range of scan rate, carbon nanotube film electrodes treated with acids showed heterogeneous electron-transfer properties, which was mainly controlled by its electron state density on the surface of the film. On the whole, the carbon nanotube electrode with nitric acid treatment presented the best electrochemical behaviors, so we chose it as an analytical electrode to determine the trace compound in dilute solution. The results demonstrated that this new electrode material exhibits superior performance characteristics for the detection of azide anion.
文摘By using both DV-Xα and EH-CO methods, the calculation studies of the structure-property relationships of a series of metal azides, of their clusters’ electronic structures in ground and excited states, of their systems with cation vacancy and the doped Pb(N3)2, as well as their crystal band structures have been conducted. The results show that the sensitivity of ionic-type metal azides varies with the degree of difficulty of electronic transition of the losing charge on N3. A metal azide with cation vacancies has a greater sensitivity than the perfect one. When doped with monovalent metal ions, lead azide’s sensitivity increased; when with trivalent ones, its sensitivity decreased; when with divalent ones, little of it changed. Compared with heavy metal azides. an alkali metal azide has a larger band gap, a smaller band width and a greater transition energy of frontier electron with a smaller amount of losing charge on N3, and thus has lower sensitivity and conductivity than heavy metal azides.
基金partially supported by the National Natural Science Foundation of China(Nos.50703033,20974098 and 20974028)the Ministry of Science and Technology of China(2009CB623605)+1 种基金the Research Grants Council of Hong Kong (603509,HKUST2/CRF/10)the University Grants Committee of Hong Kong(AoE/P-03/08)
文摘The great achievements of click chemistry have encouraged polymer scientists to use this reaction in their field. This review assembles an update of the advances of using azide-alkyne click polymerization to prepare functional polytriazoles（PTAs） with linear and hyperbranched structures.The Cu（I）-mediated click polymerization furnishes 1,4-regioregular PTAs,whereas,the metal-free click polymerization of propiolates and azides produces PTAs with 1,4-regioisomer contents up to 90%.The PTAs display advanced functions,such as aggregation-induced emission,thermal stability,biocompatibility and optical nonlinearity.
基金Guangdong Provincial Natural Science Foundation(20010102)the PhD-Degree-Bearer's Startup Foundation of Guangdong Academy of Agricultural Sciences(00-Boshi-05).
文摘Field and pot experiments were conducted using indica rice varieties with differential chalkiness. There were significant differences in root activity among the varieties. The percentages of chalky grains and chalky area were both negatively correlated with root activity expressed as α-naphthylamine oxidation ability （RA） per gram of fresh root （RAfw） , RA per spikelet （RAgrn）, or RA per sink capacity （RAsink）. The RAsink was more closely related to chalkiness than RAt, and RAgrn when varieties differed greatly in panicle size and grain weight. Application of NO3^--N fertilizer at heading resulted in higher root activity and reduced chalkiness. Application of 30 mg/L NaN3 （respiration inhibitor） resulted in reduced root activity and increased chalkiness for one variety ＇GD9501＇, but for the other variety ＇Qinluai＇ was in reverse. The percentages of chalky grains and chalky area were negatively correlated with root activity at 10 days after heading under different chemical treatments （r=-0.8567^＊ and r=-0.9211^＊＊, respectively）.
基金Project supported financially by the Program for the Development of Science and Technology of Jilin Province,China(Grant Nos.YDZJ202301ZYTS382,YDZJ202201ZYTS316,and 20230101285JC)the National Natural Science Foundation of China(Grant No.11904128)+1 种基金the Program for Science and Technology of Education Department of Jilin Province,China(Grant Nos.JJKH20220438KJ and JJKH20220423KJ)the Program for the Jilin Provincial Development and Reform Commission Project(Grant No.2022C040-6)。
文摘The high-pressure structure and elastic properties of calcium azide(Ca(N_(3))_(2))were investigated using in-situ highpressure x-ray diffraction and Raman scattering up to 54 GPa and 19 GPa,respectively.The compressibility of Ca(N_(3))_(2)changed as the pressure increased,and no phase transition occurred within the pressure from ambient pressure up to 54 GPa.The measured zero-pressure bulk modulus of Ca(N_(3))_(2)is higher than that of other alkali metal azides,due to differences in the ionic character of their metal-azide bonds.Using CASTEP,all vibration modes of Ca(N_(3))_(2)were accurately identified in the vibrational spectrum at ambient pressure.In the high-pressure vibration study,several external modes(ext.)and internal bending modes(ν_(2))of azide anions(N_(3)^(-))softened up to~7 GPa and then hardened beyond that pressure.This evidence is consistent with the variation observed in the F_(E)–f_(E)data analyzed from the XRD result,where the slope of the curve changes at 7.1 GPa.The main behaviors under pressure are the alternating compression,rotation,and bending of N_(3)^(-)ions.The bending behavior makes the structure of Ca(N_(3))_(2)more stable under pressure.
基金the financial support by the Natural Science Foundation of China(No.21203085)Promotive Research Fund for Young and Middle-aged Scientists of Shandong Province(doctor fund)(Nos.BS2011CL011 and BS2012CL009)
文摘The random copolymers grafted onto the surfaces of SiO2 hollow sphere via reverse atom transfer radical polymerization （RATRP） and ＂click＂ chemistry were investigated. A sufficient amount of peroxides, as initiating moieties, were introduced onto the surface of hollow spheres. Then styrene and 4-vinylbenzyl azide were polymerized via surface-initiated reverse atom transfer radical polymerization （SI-RATRP） using the peroxide group modified hollow sphere as initiator, resulting in hollow spheres （HS） with grafted polystyrene-co-poly（4-vinylbenzyl azide） copolymer brushes as （HS-g-PS-co-PVBA） intermedi- ate material. Subsequently, N-propargyl-carbazole （PC） was covalently bonded to HS-g-PS-co-PVBA by the ＂click＂ reaction, resulting in the HS-g-PS-co-PVBPC hybrid material. The excitation spectrum is dominated by a broad band from 350 nm to 400 nm with the maximum peak at 362 nm, attributed to the characteristic absorption of the carbazole grouD of HS-g-PS-co-PVBPC hybrid material.
文摘A new coordination complex, [Ag(IIMB)N 3], was prepared by self-assembly of asymmetric ligand 1-(1-imidazolyl)-4-(imidazol-1-ylmethyl)benzene(IIMB) with [Ag(NH 3) 2]N 3. The crystal structural analysis indicates that the structure of the complex contains fifty-two-membered macrometallacyclic rings, and the complex crystallizes in monoclinic system, space group of P2 1/c with a=0.739 8(1) nm, {b=}1.045 1(1) nm, c=1.812 4(2)nm, β=91.65(1)°, V=1.400 7(3) nm3, Z=4, D c=1.774 g/cm3, {F(000)=}744, R=0.050 5, wR=0.084 0. It is notable that the azide ion bridges two silver(Ⅰ) atoms in end-on fashion.
