A first-principles density functional approach is used to study the electronic and the elastic properties of Nb15X （X = Ti, Zr, Hf, V, Ta, Cr, Mo, and W） alloys. The elastic constants cn and c12, the shear modulus C...A first-principles density functional approach is used to study the electronic and the elastic properties of Nb15X （X = Ti, Zr, Hf, V, Ta, Cr, Mo, and W） alloys. The elastic constants cn and c12, the shear modulus CI, and the elastic modulus E（lOO） are found to exhibit similar tendencies, each as a function of valence electron number per atom （EPA）, while c44 seems unclear. Both cu and c12 of Nb15X alloys increase monotonically with the increase of EPA. The C/ and E000） also show similar tendencies. The elastic constants （except c44） increase slightly when alloying with neighbours of a higher d-transition series. Our results are supported by the bonding density distribution. When solute atoms change from Ti（Zr, Hf） to V（Ta） then to Cr（Mo, W）, the bonding electron density between the central solute atom and its first neighbouring Nb atoms is increased and becomes more anisotropic, which indicates the strong interaction and thus enhances the elastic properties of Nb-Cr（Mo, W） alloys. Under uniaxial {100） tensile loading, alloyed elements with less （more） valence electrons decrease （increase） the ideal tensile strength.展开更多
The phosphine-functionalized phosphonium-based ionic liquids(dppm-Q, dppe-Q, dppp-Q and dppb-Q) as the bi-functional ligands enable the efficient one-pot tandem hydroformylationeacetalization. It was found that, in dp...The phosphine-functionalized phosphonium-based ionic liquids(dppm-Q, dppe-Q, dppp-Q and dppb-Q) as the bi-functional ligands enable the efficient one-pot tandem hydroformylationeacetalization. It was found that, in dppm-Q, dppe-Q, dppp-Q and dppb-Q, the incorporated phosphino-fragments were responsible for Rh-catalyzed hydroformylation and the phosphoniums were in charge of the subsequent acetalization as the Lewis acid catalysts. Moreover, the diphosphonium-based ionic liquid of dppb-DQ could be applied as a co-solvent to immobilize the Rh/dppb-Q catalytic system with the advantages of the improved catalytic performance, the available catalyst recyclability, and the wide generality for the substrates.展开更多
The modified single base propellant samples were prepared by impregnating blasting oil into single base grains and deactivating deterrent in water medium. The concentration distribution of functional compositions in t...The modified single base propellant samples were prepared by impregnating blasting oil into single base grains and deactivating deterrent in water medium. The concentration distribution of functional compositions in this propellant was determined by using FTIR micro-spectroscopy. Its combustion performance was investigated by means of closed-bomb and interior ballistic tests. The results show that the concentration of NG distributes parabolically along the radius and the concentration of NA decreases from the surface to the centre exponentially. The deeper the NG impregnates, the slower the NA concentration decreases, the stronger the progressive combustion is and the better the interior ballistic performance is. When the depth corresponding to maximum NG concentration is about 1/2 of the web and the NA decreases slowly, the progressive combustion is the strongest and the interior ballistic performance is the best.展开更多
The wavelength-dependent and frequency-dependent dielectric function of wurtzite-GaN is cMculated totally from fundamental parameters such as the lattice constant using Waiter＇s ab initio model. The errors occurring ...The wavelength-dependent and frequency-dependent dielectric function of wurtzite-GaN is cMculated totally from fundamental parameters such as the lattice constant using Waiter＇s ab initio model. The errors occurring in the cMculation are carefully reduced by/inear interpolation of energy data. The Kramers-Kronig transform of the real part of greater range is obtained by extrapolation of the reM part. The calculation is time-consuming but meaningful The long-wave results are similar to the experimental data of the photon and are useful for related investigation of properties of wide-gap semiconductors such as electron scattering like the Auger recombination and impact ionization.展开更多
A compound multi-functional sensor was designed by the study on the on-line testing technology of wood-based panels, and its properties of shape, functions, size, resistance to special environment were studied in deta...A compound multi-functional sensor was designed by the study on the on-line testing technology of wood-based panels, and its properties of shape, functions, size, resistance to special environment were studied in details. The operational principles of different sensors, technical flow of manufacturing, development of software systems of special functions, and the assessments of technical specification were also be introduced. This sensor adopted many new technologies, such as the applications of piezoresistant effect and heat sensitive effect can effectively measure the pressure and temperature, digital signal processing technology was used to extract and treat signals, and resist interference, encapsulation technology was used to keep the normal run of sensor under a harsh environment. Thus, the on-line compound multi-functional temperature/pressure sensor can be applied better to supervise the production of wood-based panels. All technical specifications of the compound multi-functional sensor were tested and the results met the requirements of the equipments.展开更多
With the application of Hammer integral formulas of a continuous function on a triangular element, the numerical integral formulas of some discrete functions on the element are derived by means of decomposition and re...With the application of Hammer integral formulas of a continuous function on a triangular element, the numerical integral formulas of some discrete functions on the element are derived by means of decomposition and recombination of base functions. Hammer integral formulas are the special examples of those of the paper.展开更多
A comparative study of the extractive desulfurization(EDS) mechanism by Cu(Ⅱ) and Zn-based ILs([C_4mim]_2[MCl_4], M ? Cu(Ⅱ) or Zn)has been performed. It is found that the p–p interaction and C-H/p interaction play ...A comparative study of the extractive desulfurization(EDS) mechanism by Cu(Ⅱ) and Zn-based ILs([C_4mim]_2[MCl_4], M ? Cu(Ⅱ) or Zn)has been performed. It is found that the p–p interaction and C-H/p interaction play important roles in EDS for both Cu(Ⅱ) and Zn-based ILs,which is different from Al, Fe-based ILs. In the gas phase models, the interaction energy between Zn-based ILs and dibenzothiophene(DBT) is stronger than the interaction energy of Cu(Ⅱ)-based ILs. In order to consider the solvent effect, a generic ionic liquid of solvation model has been implemented, which is few considered in the previous calculations of EDS. It is interesting to find that the gap of interaction energies between Cu(Ⅱ), Zn-based ILs and DBT are reduced when the solvent effect is considered. In addition, by combined discussion of currently theoretical and experimental evidences for metal-based ILs with different compositions, we firstly propose that the EDS performance should be influenced by the balance of the contribution of cation, metal-based anion, metal chlorides and the viscosity.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.50771004)
文摘A first-principles density functional approach is used to study the electronic and the elastic properties of Nb15X （X = Ti, Zr, Hf, V, Ta, Cr, Mo, and W） alloys. The elastic constants cn and c12, the shear modulus CI, and the elastic modulus E（lOO） are found to exhibit similar tendencies, each as a function of valence electron number per atom （EPA）, while c44 seems unclear. Both cu and c12 of Nb15X alloys increase monotonically with the increase of EPA. The C/ and E000） also show similar tendencies. The elastic constants （except c44） increase slightly when alloying with neighbours of a higher d-transition series. Our results are supported by the bonding density distribution. When solute atoms change from Ti（Zr, Hf） to V（Ta） then to Cr（Mo, W）, the bonding electron density between the central solute atom and its first neighbouring Nb atoms is increased and becomes more anisotropic, which indicates the strong interaction and thus enhances the elastic properties of Nb-Cr（Mo, W） alloys. Under uniaxial {100） tensile loading, alloyed elements with less （more） valence electrons decrease （increase） the ideal tensile strength.
基金financially supported by the National Natural Science Foundation of China(Nos.21673077,21473058,and 21273077)
文摘The phosphine-functionalized phosphonium-based ionic liquids(dppm-Q, dppe-Q, dppp-Q and dppb-Q) as the bi-functional ligands enable the efficient one-pot tandem hydroformylationeacetalization. It was found that, in dppm-Q, dppe-Q, dppp-Q and dppb-Q, the incorporated phosphino-fragments were responsible for Rh-catalyzed hydroformylation and the phosphoniums were in charge of the subsequent acetalization as the Lewis acid catalysts. Moreover, the diphosphonium-based ionic liquid of dppb-DQ could be applied as a co-solvent to immobilize the Rh/dppb-Q catalytic system with the advantages of the improved catalytic performance, the available catalyst recyclability, and the wide generality for the substrates.
文摘The modified single base propellant samples were prepared by impregnating blasting oil into single base grains and deactivating deterrent in water medium. The concentration distribution of functional compositions in this propellant was determined by using FTIR micro-spectroscopy. Its combustion performance was investigated by means of closed-bomb and interior ballistic tests. The results show that the concentration of NG distributes parabolically along the radius and the concentration of NA decreases from the surface to the centre exponentially. The deeper the NG impregnates, the slower the NA concentration decreases, the stronger the progressive combustion is and the better the interior ballistic performance is. When the depth corresponding to maximum NG concentration is about 1/2 of the web and the NA decreases slowly, the progressive combustion is the strongest and the interior ballistic performance is the best.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFB0400102the National Basic Research Program of China under Grant Nos 2012CB3155605,2013CB632804,2014CB340002 and 2015CB351900+7 种基金the National Natural Science Foundation of China under Grant Nos 61574082,61210014,61321004,61307024 and 51561165012the High Technology Research and Development Program of China under Grant No 2015AA017101the Tsinghua University Student Research Training Projects under Grant No 1611T0157the Tsinghua University Initiative Scientific Research Program under Grant Nos 2013023Z09N and 2015THZ02-3the Open Fund of the State Key Laboratory on Integrated Optoelectronics under Grant No IOSKL2015KF10the CAEP Microsystem and THz Science and Technology Foundation under Grant No CAEPMT201505the Science Challenge Project under Grant No JCKY2016212A503the Guangdong Province Science and Technology Program under Grant No 2014B010121004
文摘The wavelength-dependent and frequency-dependent dielectric function of wurtzite-GaN is cMculated totally from fundamental parameters such as the lattice constant using Waiter＇s ab initio model. The errors occurring in the cMculation are carefully reduced by/inear interpolation of energy data. The Kramers-Kronig transform of the real part of greater range is obtained by extrapolation of the reM part. The calculation is time-consuming but meaningful The long-wave results are similar to the experimental data of the photon and are useful for related investigation of properties of wide-gap semiconductors such as electron scattering like the Auger recombination and impact ionization.
基金This project was supported by China Postdoctoral Science Funds, Jiangsu Planned Projects for Postdoctoral Research Funds and Northeast Forestry University Research Funds.
文摘A compound multi-functional sensor was designed by the study on the on-line testing technology of wood-based panels, and its properties of shape, functions, size, resistance to special environment were studied in details. The operational principles of different sensors, technical flow of manufacturing, development of software systems of special functions, and the assessments of technical specification were also be introduced. This sensor adopted many new technologies, such as the applications of piezoresistant effect and heat sensitive effect can effectively measure the pressure and temperature, digital signal processing technology was used to extract and treat signals, and resist interference, encapsulation technology was used to keep the normal run of sensor under a harsh environment. Thus, the on-line compound multi-functional temperature/pressure sensor can be applied better to supervise the production of wood-based panels. All technical specifications of the compound multi-functional sensor were tested and the results met the requirements of the equipments.
文摘With the application of Hammer integral formulas of a continuous function on a triangular element, the numerical integral formulas of some discrete functions on the element are derived by means of decomposition and recombination of base functions. Hammer integral formulas are the special examples of those of the paper.
基金financially supported by the National Natural Science Foundation of China(Nos.21646001,21506080,21406092)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘A comparative study of the extractive desulfurization(EDS) mechanism by Cu(Ⅱ) and Zn-based ILs([C_4mim]_2[MCl_4], M ? Cu(Ⅱ) or Zn)has been performed. It is found that the p–p interaction and C-H/p interaction play important roles in EDS for both Cu(Ⅱ) and Zn-based ILs,which is different from Al, Fe-based ILs. In the gas phase models, the interaction energy between Zn-based ILs and dibenzothiophene(DBT) is stronger than the interaction energy of Cu(Ⅱ)-based ILs. In order to consider the solvent effect, a generic ionic liquid of solvation model has been implemented, which is few considered in the previous calculations of EDS. It is interesting to find that the gap of interaction energies between Cu(Ⅱ), Zn-based ILs and DBT are reduced when the solvent effect is considered. In addition, by combined discussion of currently theoretical and experimental evidences for metal-based ILs with different compositions, we firstly propose that the EDS performance should be influenced by the balance of the contribution of cation, metal-based anion, metal chlorides and the viscosity.
