A three-phase confocal elliptical cylinder model is proposed to analyze micromechanics of one-dimensional hexagonal piezoelectric quasicrystal （PQC） compos- ites. Exact solutions of the phonon, phason, and electric ...A three-phase confocal elliptical cylinder model is proposed to analyze micromechanics of one-dimensional hexagonal piezoelectric quasicrystal （PQC） compos- ites. Exact solutions of the phonon, phason, and electric fields are obtained by using the conformal mapping combined with the Laurent expansion technique when the model is subject to far-field anti-plane mechanical and in-plane electric loadings. The effective elec- troelastic constants of several different composites made up of PQC, quasicrystal （QC）, and piezoelectric （PE） materials are predicted by the generalized self-consistent method. Numerical examples are conducted to show the effects of the volume fraction and the cross-sectional shape of inclusion （or fiber） on the effective electroelastic constants of these composites. Compared with other micromechanical methods, the generalized self- consistent and Mori-Tanaka methods can predict the effective electroelastic constants of the composites consistently.展开更多
We synthesised a series of ω-aminoalkyl sodium hydrogen phosphates （AAP-n-Na, n =3, 4, 5, 6, purity 〉 99%）, which have potential applications as bioactive cosmetic ingredients and surface modifiers of bone minera...We synthesised a series of ω-aminoalkyl sodium hydrogen phosphates （AAP-n-Na, n =3, 4, 5, 6, purity 〉 99%）, which have potential applications as bioactive cosmetic ingredients and surface modifiers of bone minerals （i.e. hydroxyapatites）. Results from Fourier transformed infrared （FTIR）, nuclear magnetic resonance （NMR） and high resolution mass spectroscopy, and elemental analysis all matched their chemical structures. The acid dissociation constants （pKa＇s） of each AAP-n （acid form of AAP-n-Na, n ; 2-6） were measured by potentiometric titration, showing a general increasing trend with an increase in the chain length of AAP-n. However, the pKa3 constant, which corresponds to the deprotonation of the ammonium group in AAP-n-Na, displayed an unusual decrease when n = even. This odd-even effect can be explained by the pairwise self-association of AAP-n-Na molecules in water where intermolecular hydrogen bonding in case of n=even is weaker than that in case of n=odd. All AAP-n-Na at concentrations up to 0.1% （w/v） were non-toxic to L929 fibroblasts and MG 63 osteoblast-like cells in terms of cell growth and morphology, These basic data were important for applications of AAP-n and their salts in biomedical engineering.展开更多
The effect of cathodic hydrogen charging on the tensile and constant load properties was deter- mined for an austenitic stainless steel weldment comprising a 304L steel in the solution treated condition as a base meta...The effect of cathodic hydrogen charging on the tensile and constant load properties was deter- mined for an austenitic stainless steel weldment comprising a 304L steel in the solution treated condition as a base metal and a 308L filler steel as a weld metal. Part of the 304L solution treated steel was separately given additional sensitization treatment to simulate the microstructure that would develop in the heat affected zone. Tests were performed at room temperature on notched round bar specimens. Hydrogen charging resulted in a pronounced embrittlement of the tested materials. This was manifested mainly as a considerable loss in the ductility of tensile specimens and a decrease in the time to failure and threshold stress of constant load specimens. The 308L weld metal exhibited the highest, and the 304L solution treated steel the lowest, resistance to hydrogen embrittlement. Hydrogen embrittlement was associated with the formation of strain induced martensite as well as a transition from brittle to ductile fracture morphology onwards the centre of the specimens.展开更多
Nattokinase, is an effective fibrinolytic enzyme with the potential for fighting cardiovascular disease. The aim of study was to investigate the interaction of Tb（Ⅲ） with nattokinase and the impact of Tb（Ⅲ） on t...Nattokinase, is an effective fibrinolytic enzyme with the potential for fighting cardiovascular disease. The aim of study was to investigate the interaction of Tb（Ⅲ） with nattokinase and the impact of Tb（Ⅲ） on the enzyme activity and protein stability. The binding of Tb（Ⅲ） with nattokinase was studied by fluorescence spectrum in 100 mmol/L Tris-HCl（pH 8.0）. It could be seen that the protein bound one Tb（Ⅲ） with low affinity, and the binding constants K were 2.90×10~4 L/mol at 288 K. Although the activity of nattokinase determined by tetra-peptide substrate method at proper pH and temperature was not influenced for the binding of Tb（Ⅲ）, the transformation rate of substrate was increased to 113%. To better assess the stability of protease in the absence and presence of Tb（Ⅲ）, nattokinase was unfolded through continuous concentrations urea. Based on the model of structural element, the results showed that Tb（Ⅲ） could not change the average structural element free energy of nattokinase by the measurement of enzyme activity, but it could improve the stability of the global protein by the fluorescence spectral measurement.展开更多
An analytical method was proposed dielectric properties for particulate composites. to calculate effective linear and nonlinear The method is based on an approximate solution of two-particle interaction problem, and i...An analytical method was proposed dielectric properties for particulate composites. to calculate effective linear and nonlinear The method is based on an approximate solution of two-particle interaction problem, and it can be applied to relatively high volume concentration of particles （up to 50%）. Nonlinear dielectric property was also examined by means of secant method. It is found that for low applied electric filed the proposed method is close to Stroud and Hui＇s method and for high applied electric filed it is close to Yu＇s method.展开更多
We discuss a new class of RSII braneworld cosmology exhibiting accelerated expansion and dominated by quintessence. It is explicitly demonstrated that the universe expansion history （transition from inflation to dece...We discuss a new class of RSII braneworld cosmology exhibiting accelerated expansion and dominated by quintessence. It is explicitly demonstrated that the universe expansion history （transition from inflation to deceleration epoch to acceleration and effective quintessence era） may naturally occur in such unified theory for some classes of inverse scalar potentials. Besides a decaying effective cosmological constant, the model incorporates an increasing black hole mass, an increasing Maxwellian electrical charge with cosmic time and a time-dependent brahe tension. The cosmological model exhibits several features of cosmological and astrophysical interest for both the early and late universe consistent with recent observations, in particular the ones concerned with the gravitational constants, black holes masses and charges and variation of the gauge coupling parameters with cosmic time. One interesting mark of the constructed model concerns the fact that a black hole mass surrounded by quintessence energy may increase with time even if the horizon disappears.展开更多
Accelerating vacua with maximally symmetric, but not necessarily spherical, sections for Einstein and Gauss-Bonnet gravities in generic dimensions are obtained. The acceleration parameter has the effect of shifting th...Accelerating vacua with maximally symmetric, but not necessarily spherical, sections for Einstein and Gauss-Bonnet gravities in generic dimensions are obtained. The acceleration parameter has the effect of shifting the cosmological constants in Einstein gravity, whereas in Gauss-Bonnet gravity the effective cosmological constants remain the same in the presence of acceleration as in the case without acceleration.展开更多
The anisotropic physical property is the most noteworthy feature of crystals.In this paper,the subscript change method is used to analyze the sign changes of different tensors describing physical properties in uniaxia...The anisotropic physical property is the most noteworthy feature of crystals.In this paper,the subscript change method is used to analyze the sign changes of different tensors describing physical properties in uniaxial crystals.The distribution of some physical properties in special point groups exhibits non-symmetry in eight quadrants,which should attract the attention of crystal research.The difference between the crystallographic and physical coordinate systems and the lack of crystal symmetry operations are considered to be the origins of the non-symmetry.To avoid ambiguities and difficulties in characterizing and applying crystal physical properties,eight quadrants in space should be clarified.Hence,we proposed the use of piezoelectric properties to define the positive direction of the optical coordinate axis prior to the research and applications of optical properties.展开更多
Cd F molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the Cd F molecule, electron...Cd F molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the Cd F molecule, electronic states of the molecule have not been well studied. In this paper, high accurate ab initio calculations on the Cd F molecule have been performed at the multi-reference configuration interaction level including Davidson correction（MRCI ＋ Q）. Adiabatic potential energy curves（PECs） of the 14 low-lying Λ–S states correlating with the two lowest dissociation limits Cd（~1S_g） ＋ F（~2P_u） and Cd（~3P_u） ＋ F（~2P_u） have been constructed. For the bound Λ–S and ？ states, the dominant electronic configurations and spectroscopic constants are obtained,and the calculated spectroscopic constants of bound states are consistent with previous experimental results. The dipole moments（DMs） of 2 Σ＋ and 2Π are determined, and the spin–orbit（SO） matrix elements between each pair of X2Σ＋, 22Σ＋, 12Π, and 22Π are obtained. The results indicate that the sudden changes of DMs and SO matrix elements arise from the variation of the electronic configurations around the avoided crossing region. Moreover,the Franck–Condon factors（FCFs）, the transition dipole moments（TDMs）, and radiative lifetimes of low-lying states-the ground state X2Σ＋are determined. Finally, the transitional properties of 22Π–X2Σ＋and 22Σ＋–X2Σ＋are studied. Based on our computed spectroscopic information of Cd F, the feasibility and challenge for laser cooling of Cd F molecule are discussed.展开更多
The effect of dielectric constant contrast and the filling factor to the photonic bandgap in a 2-D square lattice photonic crystal is discussed. The location, width and number of photonic bandgap can be modulated.
The periodic one-dimensional hopping model is useful for studying the motion of microscopic particles in the thermal noise environment. Based on the explicit formulations of mean velocity, mean first passage time and ...The periodic one-dimensional hopping model is useful for studying the motion of microscopic particles in the thermal noise environment. Based on the explicit formulations of mean velocity, mean first passage time and effective diffusion constant, a general N internal states or even infinite internal states model can be approximated by a one state model that retains the basic properties of the original process. This effective description aids the analysis of biochemical and biophysical problems. This effective description also implies that, to some extent, many processes can be well described by simple two-state models, or even one-state models.展开更多
基金Projected supported by the National Natural Science Foundation of China(Nos.11502123 and11262012)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2015JQ01)
文摘A three-phase confocal elliptical cylinder model is proposed to analyze micromechanics of one-dimensional hexagonal piezoelectric quasicrystal （PQC） compos- ites. Exact solutions of the phonon, phason, and electric fields are obtained by using the conformal mapping combined with the Laurent expansion technique when the model is subject to far-field anti-plane mechanical and in-plane electric loadings. The effective elec- troelastic constants of several different composites made up of PQC, quasicrystal （QC）, and piezoelectric （PE） materials are predicted by the generalized self-consistent method. Numerical examples are conducted to show the effects of the volume fraction and the cross-sectional shape of inclusion （or fiber） on the effective electroelastic constants of these composites. Compared with other micromechanical methods, the generalized self- consistent and Mori-Tanaka methods can predict the effective electroelastic constants of the composites consistently.
基金financial support from the National Natural Science Foundation of China (No. 50973069)
文摘We synthesised a series of ω-aminoalkyl sodium hydrogen phosphates （AAP-n-Na, n =3, 4, 5, 6, purity 〉 99%）, which have potential applications as bioactive cosmetic ingredients and surface modifiers of bone minerals （i.e. hydroxyapatites）. Results from Fourier transformed infrared （FTIR）, nuclear magnetic resonance （NMR） and high resolution mass spectroscopy, and elemental analysis all matched their chemical structures. The acid dissociation constants （pKa＇s） of each AAP-n （acid form of AAP-n-Na, n ; 2-6） were measured by potentiometric titration, showing a general increasing trend with an increase in the chain length of AAP-n. However, the pKa3 constant, which corresponds to the deprotonation of the ammonium group in AAP-n-Na, displayed an unusual decrease when n = even. This odd-even effect can be explained by the pairwise self-association of AAP-n-Na molecules in water where intermolecular hydrogen bonding in case of n=even is weaker than that in case of n=odd. All AAP-n-Na at concentrations up to 0.1% （w/v） were non-toxic to L929 fibroblasts and MG 63 osteoblast-like cells in terms of cell growth and morphology, These basic data were important for applications of AAP-n and their salts in biomedical engineering.
文摘The effect of cathodic hydrogen charging on the tensile and constant load properties was deter- mined for an austenitic stainless steel weldment comprising a 304L steel in the solution treated condition as a base metal and a 308L filler steel as a weld metal. Part of the 304L solution treated steel was separately given additional sensitization treatment to simulate the microstructure that would develop in the heat affected zone. Tests were performed at room temperature on notched round bar specimens. Hydrogen charging resulted in a pronounced embrittlement of the tested materials. This was manifested mainly as a considerable loss in the ductility of tensile specimens and a decrease in the time to failure and threshold stress of constant load specimens. The 308L weld metal exhibited the highest, and the 304L solution treated steel the lowest, resistance to hydrogen embrittlement. Hydrogen embrittlement was associated with the formation of strain induced martensite as well as a transition from brittle to ductile fracture morphology onwards the centre of the specimens.
基金Project supported by the National Natural Science Foundation of China(21571117)the PhD Programs Foundation of the Ministry of Education of China(20131401110011)
文摘Nattokinase, is an effective fibrinolytic enzyme with the potential for fighting cardiovascular disease. The aim of study was to investigate the interaction of Tb（Ⅲ） with nattokinase and the impact of Tb（Ⅲ） on the enzyme activity and protein stability. The binding of Tb（Ⅲ） with nattokinase was studied by fluorescence spectrum in 100 mmol/L Tris-HCl（pH 8.0）. It could be seen that the protein bound one Tb（Ⅲ） with low affinity, and the binding constants K were 2.90×10~4 L/mol at 288 K. Although the activity of nattokinase determined by tetra-peptide substrate method at proper pH and temperature was not influenced for the binding of Tb（Ⅲ）, the transformation rate of substrate was increased to 113%. To better assess the stability of protease in the absence and presence of Tb（Ⅲ）, nattokinase was unfolded through continuous concentrations urea. Based on the model of structural element, the results showed that Tb（Ⅲ） could not change the average structural element free energy of nattokinase by the measurement of enzyme activity, but it could improve the stability of the global protein by the fluorescence spectral measurement.
基金Project supported by the National Natural Science Foundation of China (No.10325210)
文摘An analytical method was proposed dielectric properties for particulate composites. to calculate effective linear and nonlinear The method is based on an approximate solution of two-particle interaction problem, and it can be applied to relatively high volume concentration of particles （up to 50%）. Nonlinear dielectric property was also examined by means of secant method. It is found that for low applied electric filed the proposed method is close to Stroud and Hui＇s method and for high applied electric filed it is close to Yu＇s method.
文摘We discuss a new class of RSII braneworld cosmology exhibiting accelerated expansion and dominated by quintessence. It is explicitly demonstrated that the universe expansion history （transition from inflation to deceleration epoch to acceleration and effective quintessence era） may naturally occur in such unified theory for some classes of inverse scalar potentials. Besides a decaying effective cosmological constant, the model incorporates an increasing black hole mass, an increasing Maxwellian electrical charge with cosmic time and a time-dependent brahe tension. The cosmological model exhibits several features of cosmological and astrophysical interest for both the early and late universe consistent with recent observations, in particular the ones concerned with the gravitational constants, black holes masses and charges and variation of the gauge coupling parameters with cosmic time. One interesting mark of the constructed model concerns the fact that a black hole mass surrounded by quintessence energy may increase with time even if the horizon disappears.
基金Supported by the National Natural Science Foundation of China (NSFC) under Grant No.10875059
文摘Accelerating vacua with maximally symmetric, but not necessarily spherical, sections for Einstein and Gauss-Bonnet gravities in generic dimensions are obtained. The acceleration parameter has the effect of shifting the cosmological constants in Einstein gravity, whereas in Gauss-Bonnet gravity the effective cosmological constants remain the same in the presence of acceleration as in the case without acceleration.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51772170,51572155,and 11504389)the National Key Research and Development Program of China(Grant No.2016YFB1102201)the Young Scholars Program(Grant No.2018WLJH67).
文摘The anisotropic physical property is the most noteworthy feature of crystals.In this paper,the subscript change method is used to analyze the sign changes of different tensors describing physical properties in uniaxial crystals.The distribution of some physical properties in special point groups exhibits non-symmetry in eight quadrants,which should attract the attention of crystal research.The difference between the crystallographic and physical coordinate systems and the lack of crystal symmetry operations are considered to be the origins of the non-symmetry.To avoid ambiguities and difficulties in characterizing and applying crystal physical properties,eight quadrants in space should be clarified.Hence,we proposed the use of piezoelectric properties to define the positive direction of the optical coordinate axis prior to the research and applications of optical properties.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11604052,11404180,and 11574114)the Natural Science Foundation of Heilongjiang Province,China(Grant No.A2015010)+3 种基金the Natural Science Foundation of Anhui Province,China(Grant No.1608085MA10)the International Science&Technology Cooperation Program of Anhui Province,China(Grant No.1403062027)the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province,China(Grant No.2015095)the Natural Science Foundation of Jilin Province,China(Grant No.20150101003JC)
文摘Cd F molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the Cd F molecule, electronic states of the molecule have not been well studied. In this paper, high accurate ab initio calculations on the Cd F molecule have been performed at the multi-reference configuration interaction level including Davidson correction（MRCI ＋ Q）. Adiabatic potential energy curves（PECs） of the 14 low-lying Λ–S states correlating with the two lowest dissociation limits Cd（~1S_g） ＋ F（~2P_u） and Cd（~3P_u） ＋ F（~2P_u） have been constructed. For the bound Λ–S and ？ states, the dominant electronic configurations and spectroscopic constants are obtained,and the calculated spectroscopic constants of bound states are consistent with previous experimental results. The dipole moments（DMs） of 2 Σ＋ and 2Π are determined, and the spin–orbit（SO） matrix elements between each pair of X2Σ＋, 22Σ＋, 12Π, and 22Π are obtained. The results indicate that the sudden changes of DMs and SO matrix elements arise from the variation of the electronic configurations around the avoided crossing region. Moreover,the Franck–Condon factors（FCFs）, the transition dipole moments（TDMs）, and radiative lifetimes of low-lying states-the ground state X2Σ＋are determined. Finally, the transitional properties of 22Π–X2Σ＋and 22Σ＋–X2Σ＋are studied. Based on our computed spectroscopic information of Cd F, the feasibility and challenge for laser cooling of Cd F molecule are discussed.
基金This work was supported by the National Nature Science Foundation of China under grants No. 60225011major state basic research program under grant No. G20000366
文摘The effect of dielectric constant contrast and the filling factor to the photonic bandgap in a 2-D square lattice photonic crystal is discussed. The location, width and number of photonic bandgap can be modulated.
基金the National Natural Science Foundation of China(Grant No. 10701029)
文摘The periodic one-dimensional hopping model is useful for studying the motion of microscopic particles in the thermal noise environment. Based on the explicit formulations of mean velocity, mean first passage time and effective diffusion constant, a general N internal states or even infinite internal states model can be approximated by a one state model that retains the basic properties of the original process. This effective description aids the analysis of biochemical and biophysical problems. This effective description also implies that, to some extent, many processes can be well described by simple two-state models, or even one-state models.
