In this paper,we consider a quasilinear parabolic-parabolic chemotaxis model with nonlinear diffusivity,aggregation and logistic damping source:■where k1 epu≤D(u) or k1 up≤D(u);k2 equ≤S(u)≤k3 equ;g(u)≤a-beku.It ...In this paper,we consider a quasilinear parabolic-parabolic chemotaxis model with nonlinear diffusivity,aggregation and logistic damping source:■where k1 epu≤D(u) or k1 up≤D(u);k2 equ≤S(u)≤k3 equ;g(u)≤a-beku.It is proved that,if q b0 for some constant b0> 0,then there exists a unique classical solution which is globally bounded.The results show the effect of the aggregation and the logistic damping source on the existence of globally bounded solutions.展开更多
This paper deals with blow-up solutions for parabolic equations coupled via localized exponential sources, subject to homogeneous Dirichlet boundary con- ditions. The criteria are proposed to identify simultaneous and...This paper deals with blow-up solutions for parabolic equations coupled via localized exponential sources, subject to homogeneous Dirichlet boundary con- ditions. The criteria are proposed to identify simultaneous and non-simultaneous blow-up solutions. The related classification for the four nonlinear parameters in the model is optimal and complete.展开更多
Titanitum-carbon anion clusters with a mass range up to 1800 amu have been generated in a Smalley-type cluster source involving a target rod composed of titanium and graphite powders, and have been analysed by time-of...Titanitum-carbon anion clusters with a mass range up to 1800 amu have been generated in a Smalley-type cluster source involving a target rod composed of titanium and graphite powders, and have been analysed by time-of-flight mass spectrometry. In the lower mass range (up to 1200 amu), our mass spectrum reproduces all the magic numbers, which have been reported previously, i.e. Ti_(3)C_(8)^(-), Ti_(6)C_(13)^(-), Ti_(7)C_(13)^(-), Ti_(9)C_(15)^(-), Ti_(13)C_(22)^(-), and Ti_(14)C_(24)^(-), in spite of many differences in experimental conditions. In the higher mass range (1200-1800 amu), we observe new magic numbers at Ti_(15)C_(26)^(-), Ti_(20)C_(33)^(-)/Ti_(20)C_(34)^(-) and Ti_(25)C_(42)^(-), which cannot be accounted for by the previously proposed structural growth patterns. All the magic and local maximum Ti_(x)C_(y) peaks have a metal-to-carbon ratio of approximately 1:1.7. The present results suggest a further complexity to the structural growth patterns of the transition metal-carbon mixed cluster systems.展开更多
Using a laser vaporization/pulsed molecular beam cluster source,Al cluster anions and Al-C mixed cluster anions are produced and recorded by a time of flight mass spectrometer.Mass abundance spectra of the Al cluster ...Using a laser vaporization/pulsed molecular beam cluster source,Al cluster anions and Al-C mixed cluster anions are produced and recorded by a time of flight mass spectrometer.Mass abundance spectra of the Al cluster anions in the size range from Al_(2)^(-)to Al_(42)^(-)show that Al_(13)^(-),Al_(23)^(-),Al_(35)^(-),and slightly,Al_(37)^(-)are local maxima,as predicted by the electronic jellium model.Mixed clusters Aln C-and Aln C_(2)^(-)are also shown,among which the most abundant species are Al3 C2,Al6 C_(2)^(-),A_(l7)C^(-)and A_(l7)C_(2)^(-)in the small size range.The formation mechanism of these products is discussed.展开更多
Two types of mass spectra for anionic carbon clusters Cn have been revealed using laser vaporization and pulsed molecular beam techniques.The less structured mass spectrum characteristic of the magic-numbers at n=5,8,...Two types of mass spectra for anionic carbon clusters Cn have been revealed using laser vaporization and pulsed molecular beam techniques.The less structured mass spectrum characteristic of the magic-numbers at n=5,8,",15,and 17 is established at the early stage of the cluster formation process,namely,in the laser vaporization,process.The more structured one is featured for a regular odd-even alternation and the magic numbers at n=IO,12,16,18j 22j and 28,and has been developed only after extensive clustering and qnenching processes,where low-energy electron attachment plays a vital role.Transition between these two types of mass spectra can be realized by controlling either the strength of the pulsed gas flow or the synchronism between the gas How and the laser vaporization.展开更多
Argon clusters are produced in the process of adiabatic expansion of a high backing pressure gas into vacuum through a nozzle.The cluster size is determined by a Rayleigh scattering measurement.The scattered signal me...Argon clusters are produced in the process of adiabatic expansion of a high backing pressure gas into vacuum through a nozzle.The cluster size is determined by a Rayleigh scattering measurement.The scattered signal measured is proportional to the 2.78th power of gas stagnation pressure.The average cluster sizes vary from 100 to more than 12000 atoms/cluster with the argon gas backing pressures ranging between 3 to 45 atm.展开更多
In this paper,we deal with some fast di usion equations ut=um+au vp and vt=△v^n+bu^qv^βsubject to null Dirichlet boundary conditions.We prove that every solution vanishes in nite time for pq>(m-α)(n-β),m>α...In this paper,we deal with some fast di usion equations ut=um+au vp and vt=△v^n+bu^qv^βsubject to null Dirichlet boundary conditions.We prove that every solution vanishes in nite time for pq>(m-α)(n-β),m>αand n>β,where the exact relation of initial data is determined with the aid of some Sobolev Embedding inequalities.If pd<(m-α)(n-β),m>αand n>β,we show the barriers of the initial data which lead to the non-extinction of solutions.For the case pq=(m-α)(n-β),the solutions vanish for small initial data.The results fill in a gap for the case pq<mn in Nonlinear Anal.Real World Appl.4(2013)1931-1937.The coecients a and b play a vital role in the existence of non-extinction weak solution provided that a and b are large enough.At last,we use the scaling methods to determine some exponent regions where one of the components would blow up alone for some suitable initial data.展开更多
This paper deals with the degenerate and singular parabolic equations coupled via nonlinear nonlocal reactions, subject to zero-Dirichlet boundary conditions. After giving the existence and uniqueness of local classic...This paper deals with the degenerate and singular parabolic equations coupled via nonlinear nonlocal reactions, subject to zero-Dirichlet boundary conditions. After giving the existence and uniqueness of local classical nonnegative solutions, we show critical blowup exponents for the solutions of the system. Moreover, uniform blow-up behaviors near the blow-up time are obtained for simultaneous blow-up solutions, divided into four subcases.展开更多
Objective： To determine the pyrolysis characteristics of calcined and processed calamine, qualitatively and quantitatively compare the contents of related elements, morphology and functional groups of the pyrolysis p...Objective： To determine the pyrolysis characteristics of calcined and processed calamine, qualitatively and quantitatively compare the contents of related elements, morphology and functional groups of the pyrolysis products dried at different heating temperatures and explore the critical temperature and the optimal drying temperature for the process of calamine with Huanglian Decoction（HLD, 黄连汤） and San Huang Decoction（SHD, 三黄汤）. Methods： Pyrolysis products were prepared by programmable and constantly heating the calcined and processed calamine to or at different heating temperatures. Thermogravimetry（TG） was used to test their pyrolysis characteristics. Fourier transform infrared spectroscopy and scanning electron microscopeenergy dispersive spectrometer were used to determine their morphology, functional groups and element contents. Page model was used to investigate the constant drying kinetics of processed calamine. Results： The adding of HLD or SHD to calcined calamine（CC） can slow its weight loss in drying pyrolysis process. The temperature ranges where HLD and SHD can affect its weight loss were 65–150 ℃ and 74–180 ℃, respectively. The drying temperature was optimized as 90 ℃. The drying kinetic for the processed calamine fits Page model shows good linearity. Conclusions： The critical temperature and the optimal drying temperature where HLD and SHD can affect the weight loss rate in the process of calamine were explored using the theories and methods of both biophysical chemistry and processing of Chinese materia medica. This work provides a good example for the study of the process of other Chinese medicines using modern analytical techniques.展开更多
基金supported by Shandong Provincial Natural Science Foundation,China(ZR2017LA003)
文摘In this paper,we consider a quasilinear parabolic-parabolic chemotaxis model with nonlinear diffusivity,aggregation and logistic damping source:■where k1 epu≤D(u) or k1 up≤D(u);k2 equ≤S(u)≤k3 equ;g(u)≤a-beku.It is proved that,if q b0 for some constant b0> 0,then there exists a unique classical solution which is globally bounded.The results show the effect of the aggregation and the logistic damping source on the existence of globally bounded solutions.
文摘This paper deals with blow-up solutions for parabolic equations coupled via localized exponential sources, subject to homogeneous Dirichlet boundary con- ditions. The criteria are proposed to identify simultaneous and non-simultaneous blow-up solutions. The related classification for the four nonlinear parameters in the model is optimal and complete.
基金Supported by the National Natural Science Foundation of China Under Grant No.29890210the National Major Basic Research Development Program。
文摘Titanitum-carbon anion clusters with a mass range up to 1800 amu have been generated in a Smalley-type cluster source involving a target rod composed of titanium and graphite powders, and have been analysed by time-of-flight mass spectrometry. In the lower mass range (up to 1200 amu), our mass spectrum reproduces all the magic numbers, which have been reported previously, i.e. Ti_(3)C_(8)^(-), Ti_(6)C_(13)^(-), Ti_(7)C_(13)^(-), Ti_(9)C_(15)^(-), Ti_(13)C_(22)^(-), and Ti_(14)C_(24)^(-), in spite of many differences in experimental conditions. In the higher mass range (1200-1800 amu), we observe new magic numbers at Ti_(15)C_(26)^(-), Ti_(20)C_(33)^(-)/Ti_(20)C_(34)^(-) and Ti_(25)C_(42)^(-), which cannot be accounted for by the previously proposed structural growth patterns. All the magic and local maximum Ti_(x)C_(y) peaks have a metal-to-carbon ratio of approximately 1:1.7. The present results suggest a further complexity to the structural growth patterns of the transition metal-carbon mixed cluster systems.
基金Supported by the National Natural Science Foundation of China under Grant No.29890210,and the National Climbing Project.
文摘Using a laser vaporization/pulsed molecular beam cluster source,Al cluster anions and Al-C mixed cluster anions are produced and recorded by a time of flight mass spectrometer.Mass abundance spectra of the Al cluster anions in the size range from Al_(2)^(-)to Al_(42)^(-)show that Al_(13)^(-),Al_(23)^(-),Al_(35)^(-),and slightly,Al_(37)^(-)are local maxima,as predicted by the electronic jellium model.Mixed clusters Aln C-and Aln C_(2)^(-)are also shown,among which the most abundant species are Al3 C2,Al6 C_(2)^(-),A_(l7)C^(-)and A_(l7)C_(2)^(-)in the small size range.The formation mechanism of these products is discussed.
基金Supported by the National Natural Science Foundation of China under Grant No.29890210.
文摘Two types of mass spectra for anionic carbon clusters Cn have been revealed using laser vaporization and pulsed molecular beam techniques.The less structured mass spectrum characteristic of the magic-numbers at n=5,8,",15,and 17 is established at the early stage of the cluster formation process,namely,in the laser vaporization,process.The more structured one is featured for a regular odd-even alternation and the magic numbers at n=IO,12,16,18j 22j and 28,and has been developed only after extensive clustering and qnenching processes,where low-energy electron attachment plays a vital role.Transition between these two types of mass spectra can be realized by controlling either the strength of the pulsed gas flow or the synchronism between the gas How and the laser vaporization.
基金Supported by the National Climbing Project,the National Natural Science Foundation of China under Grant No.29890210,the Major Project for the Fundamental Research of Chinese Academy of Sciences.
文摘Argon clusters are produced in the process of adiabatic expansion of a high backing pressure gas into vacuum through a nozzle.The cluster size is determined by a Rayleigh scattering measurement.The scattered signal measured is proportional to the 2.78th power of gas stagnation pressure.The average cluster sizes vary from 100 to more than 12000 atoms/cluster with the argon gas backing pressures ranging between 3 to 45 atm.
基金Supported by Shandong Provincial Natural Science Foundation of China。
文摘In this paper,we deal with some fast di usion equations ut=um+au vp and vt=△v^n+bu^qv^βsubject to null Dirichlet boundary conditions.We prove that every solution vanishes in nite time for pq>(m-α)(n-β),m>αand n>β,where the exact relation of initial data is determined with the aid of some Sobolev Embedding inequalities.If pd<(m-α)(n-β),m>αand n>β,we show the barriers of the initial data which lead to the non-extinction of solutions.For the case pq=(m-α)(n-β),the solutions vanish for small initial data.The results fill in a gap for the case pq<mn in Nonlinear Anal.Real World Appl.4(2013)1931-1937.The coecients a and b play a vital role in the existence of non-extinction weak solution provided that a and b are large enough.At last,we use the scaling methods to determine some exponent regions where one of the components would blow up alone for some suitable initial data.
基金Supported by the National Natural Science Foundation of China（11201483） Supported by the Natural Science Foundation of Shandong Province Supported by the Fundamental Research Funds for the Central Universities
文摘This paper deals with the degenerate and singular parabolic equations coupled via nonlinear nonlocal reactions, subject to zero-Dirichlet boundary conditions. After giving the existence and uniqueness of local classical nonnegative solutions, we show critical blowup exponents for the solutions of the system. Moreover, uniform blow-up behaviors near the blow-up time are obtained for simultaneous blow-up solutions, divided into four subcases.
基金Supported by the the Key Technology Research for TCM Modernization of Shanxi Province"Zhendong"Special Project(No.2014ZD0302)
文摘Objective： To determine the pyrolysis characteristics of calcined and processed calamine, qualitatively and quantitatively compare the contents of related elements, morphology and functional groups of the pyrolysis products dried at different heating temperatures and explore the critical temperature and the optimal drying temperature for the process of calamine with Huanglian Decoction（HLD, 黄连汤） and San Huang Decoction（SHD, 三黄汤）. Methods： Pyrolysis products were prepared by programmable and constantly heating the calcined and processed calamine to or at different heating temperatures. Thermogravimetry（TG） was used to test their pyrolysis characteristics. Fourier transform infrared spectroscopy and scanning electron microscopeenergy dispersive spectrometer were used to determine their morphology, functional groups and element contents. Page model was used to investigate the constant drying kinetics of processed calamine. Results： The adding of HLD or SHD to calcined calamine（CC） can slow its weight loss in drying pyrolysis process. The temperature ranges where HLD and SHD can affect its weight loss were 65–150 ℃ and 74–180 ℃, respectively. The drying temperature was optimized as 90 ℃. The drying kinetic for the processed calamine fits Page model shows good linearity. Conclusions： The critical temperature and the optimal drying temperature where HLD and SHD can affect the weight loss rate in the process of calamine were explored using the theories and methods of both biophysical chemistry and processing of Chinese materia medica. This work provides a good example for the study of the process of other Chinese medicines using modern analytical techniques.
