We propose a new concept, the centre of energy, to study energy diffusion and heat conduction in a one-dimensional hard-point model. For the diatom model, we find an anomalous energy diffusion as （x2） - tβ with β ...We propose a new concept, the centre of energy, to study energy diffusion and heat conduction in a one-dimensional hard-point model. For the diatom model, we find an anomalous energy diffusion as （x2） - tβ with β = 1.33, which is independent of initial condition and mass rate. The present model can be viewed as the model composed by independent quasi-particles, the centre of energy. In this way, heat current can be calculated. Based on the theory of dynamic billiard, the divergent exponent of heat conductivity is estimated to be α = 0.33, which is confirmed by a simple numerical calculation.展开更多
A local alternating segment explicit - implicit method for the solution of 2D diffusion equations is presented in this paper .The method is unconditionally stable and has the obvious property of parallelism. Some nume...A local alternating segment explicit - implicit method for the solution of 2D diffusion equations is presented in this paper .The method is unconditionally stable and has the obvious property of parallelism. Some numerical experiments show the method is not only simple but also more accurate.展开更多
The fabrication of a new type of one-dimensional Au-Ag porous nanotube（NPT） structure was presented based on a facile combination of nanocrystal growth and surface modification.Ag nanowires with various diameters we...The fabrication of a new type of one-dimensional Au-Ag porous nanotube（NPT） structure was presented based on a facile combination of nanocrystal growth and surface modification.Ag nanowires with various diameters were firstly served as the chemical plating templates via a polyol-process.Then,one-dimensional（1D） Au-Ag porous nanostructures with tailored structural features could be prepared by controlling the individual steps involved in this process,such as nanowire growth,surface modification,thermal diffusion,and dealloying.Structural characterizations reveal these Au-Ag porous nanotubes,non-porous nanotubes and porous nanowires possess novel nano-architectures with multimodal open porosity and excellent structural continuity and integrity,which make them particularly desirable as novel 1D nanocarriers for biomedical,drug delivery and sensing applications.展开更多
Alginate has been widely used in cell microencapsulation and drug delivery systems in the form of gel beads or microcapsules.Although an alternative novel emulsification-internal gelation technology has been establish...Alginate has been widely used in cell microencapsulation and drug delivery systems in the form of gel beads or microcapsules.Although an alternative novel emulsification-internal gelation technology has been established and both the properties and the potential applications of the beads in drug delivery systems have been studied,the mechanism has not been well understood compared with the traditional droplet method（external gelation technology）.On the basis of our previous knowledge that the novel technology is composed of complicatedly consecutive processes with multistep diffusion and reaction,and the diffusion of acetic acid across oil/water interface being the prerequisite that determines the occurrence and rate for the reactions and the structures and properties of final produced gel beads,a special emphasis was placed on the diffusion process.With the aid of diffusion modeling and simple experimental design,the diffusion rate constant and diffusion coefficient of acetic acid across oil/water interface were determined to be in the orders of magnitude of 10-6 and 10-16,respectively.This knowledge will be of particular importance in understanding and interpreting the formation,structure of the gel beads and the relationship between the structure and properties and guiding the preparation and quality control of the gel beads.展开更多
Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertic...Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertical temperature diffusion coefficient based on the observed temperature profiles. The sensitivity of the inverse model in the idealized and actual conditions is tested in detail. It can be found that this inverse model has high feasibility under multiple situations ensuring the stability of the inverse model, and can be considered as an efficient way to estimate the temperature diffusion coefficient in the weak current regions of the ocean. Here, the hydrographic profiles from Argo floats are used to estimate the temporal and spatial distribution of the vertical mixing in the north central Pacific based on this inverse method. It is further found that the vertical mixing in the upper ocean displays a distinct seasonal variation with the amplitude decreasing with depth, and the vertical mixing over rough topography is stronger than that over smooth topography It is suggested that the high-resolution profiles from Argo floats and a more reasonable design of the inverse scheme will serve to understand mixing processes.展开更多
Protein XPA plays critical roles in nucleotide excision repair pathway.Recent experimental work showed that the functional dynamics of XPA involves the one-dimensional diffusion along DNA to search the damage site.Her...Protein XPA plays critical roles in nucleotide excision repair pathway.Recent experimental work showed that the functional dynamics of XPA involves the one-dimensional diffusion along DNA to search the damage site.Here,we investigate the involved dynamical process using extensive coarse-grained molecular simulations at various salt concentrations.The results demonstrated strong salt concentration dependence of the diffusion mechanisms.At low salt concentrations,the one-dimensional diffusion with rotational coupling is the dominant mechanism.At high salt concentrations,the diffusion by three-dimensional mechanism becomes more probable.At wide range of salt concentrations,the residues involved in the DNA binding are similar and the one-dimensional diffusion of XPA along DNA displays sub-diffusive feature.This sub-diffusive feature is tentatively attributed to diverse strengths of XPA-DNA interactions.In addition,we showed that both binding to DNA and increasing salt concentration tend to stretch the conformation of the XPA,which increases the exposure extent of the sites for the binding of other repair proteins.展开更多
This paper describes an accurate method of approximating the moments of the first-passage time for the birth and death Gross National Product GNP diffusion process when the GNP is a determined value or constant absorb...This paper describes an accurate method of approximating the moments of the first-passage time for the birth and death Gross National Product GNP diffusion process when the GNP is a determined value or constant absorbing barrier. This was done by approximating the differential equations by equivalent difference equations.展开更多
This article studies the optimal proportional reinsurance and investment problem under a constant elasticity of variance （CEV） model. Assume that the insurer＇s surplus process follows a jump-diffusion process, the ...This article studies the optimal proportional reinsurance and investment problem under a constant elasticity of variance （CEV） model. Assume that the insurer＇s surplus process follows a jump-diffusion process, the insurer can purchase proportional reinsurance from the reinsurer via the variance principle and invest in a risk-free asset and a risky asset whose price is modeled by a CEV model. The diffusion term can explain the uncertainty associated with the surplus of the insurer or the additional small claims. The objective of the insurer is to maximize the expected exponential utility of terminal wealth. This optimization problem is studied in two cases depending on the diffusion term＇s explanation. In all cases, by using techniques of stochastic control theory, closed-form expressions for the value functions and optimal strategies are obtained.展开更多
We study quasi-stationarity for one-dimensional diffusions killed at 0, when 0 is a regular boundary and ＋∞ is an entrance boundary. We give a necessary and sufficient condition for the existence of exactly one quas...We study quasi-stationarity for one-dimensional diffusions killed at 0, when 0 is a regular boundary and ＋∞ is an entrance boundary. We give a necessary and sufficient condition for the existence of exactly one quasistationary distribution, and we also show that this distribution attracts all initial distributions.展开更多
In this paper new diffuse solar radiation equations were established for Antalya,Turkey.For this purpose current equations from the literature which were functions of the clearness index and/or the sunshine fraction w...In this paper new diffuse solar radiation equations were established for Antalya,Turkey.For this purpose current equations from the literature which were functions of the clearness index and/or the sunshine fraction were examined.Nine(9)equations were selected to determine the regression constants of the new equations.In conclusion the best equation among the new equations was introduced on the basis of different statistical indicators.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 10605020)the Natural Science Foundation of Zhejiang Province of China (Grant No. Y605376.)
文摘We propose a new concept, the centre of energy, to study energy diffusion and heat conduction in a one-dimensional hard-point model. For the diatom model, we find an anomalous energy diffusion as （x2） - tβ with β = 1.33, which is independent of initial condition and mass rate. The present model can be viewed as the model composed by independent quasi-particles, the centre of energy. In this way, heat current can be calculated. Based on the theory of dynamic billiard, the divergent exponent of heat conductivity is estimated to be α = 0.33, which is confirmed by a simple numerical calculation.
文摘A local alternating segment explicit - implicit method for the solution of 2D diffusion equations is presented in this paper .The method is unconditionally stable and has the obvious property of parallelism. Some numerical experiments show the method is not only simple but also more accurate.
基金Project (2012CB932800) supported by the National Basic Research Program of ChinaProject (2012M521330) supported by China Postdoctoral Science Foundation
文摘The fabrication of a new type of one-dimensional Au-Ag porous nanotube（NPT） structure was presented based on a facile combination of nanocrystal growth and surface modification.Ag nanowires with various diameters were firstly served as the chemical plating templates via a polyol-process.Then,one-dimensional（1D） Au-Ag porous nanostructures with tailored structural features could be prepared by controlling the individual steps involved in this process,such as nanowire growth,surface modification,thermal diffusion,and dealloying.Structural characterizations reveal these Au-Ag porous nanotubes,non-porous nanotubes and porous nanowires possess novel nano-architectures with multimodal open porosity and excellent structural continuity and integrity,which make them particularly desirable as novel 1D nanocarriers for biomedical,drug delivery and sensing applications.
基金Supported by the National Natural Science Foundation of China(No.30472102)the National Basic Research Program ofChina(Nos.2002CB713804and2007CB714305).
文摘Alginate has been widely used in cell microencapsulation and drug delivery systems in the form of gel beads or microcapsules.Although an alternative novel emulsification-internal gelation technology has been established and both the properties and the potential applications of the beads in drug delivery systems have been studied,the mechanism has not been well understood compared with the traditional droplet method（external gelation technology）.On the basis of our previous knowledge that the novel technology is composed of complicatedly consecutive processes with multistep diffusion and reaction,and the diffusion of acetic acid across oil/water interface being the prerequisite that determines the occurrence and rate for the reactions and the structures and properties of final produced gel beads,a special emphasis was placed on the diffusion process.With the aid of diffusion modeling and simple experimental design,the diffusion rate constant and diffusion coefficient of acetic acid across oil/water interface were determined to be in the orders of magnitude of 10-6 and 10-16,respectively.This knowledge will be of particular importance in understanding and interpreting the formation,structure of the gel beads and the relationship between the structure and properties and guiding the preparation and quality control of the gel beads.
基金The Program for New Century Excellent Talents in University of the Ministry of Education under contract No.NCET-10-0764the National High Technology Research and Development Program of China(863 Program)under contract No.2013AA09A502the National Natural Science Foundation of China under contract Nos 40876015 and 41176010
文摘Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertical temperature diffusion coefficient based on the observed temperature profiles. The sensitivity of the inverse model in the idealized and actual conditions is tested in detail. It can be found that this inverse model has high feasibility under multiple situations ensuring the stability of the inverse model, and can be considered as an efficient way to estimate the temperature diffusion coefficient in the weak current regions of the ocean. Here, the hydrographic profiles from Argo floats are used to estimate the temporal and spatial distribution of the vertical mixing in the north central Pacific based on this inverse method. It is further found that the vertical mixing in the upper ocean displays a distinct seasonal variation with the amplitude decreasing with depth, and the vertical mixing over rough topography is stronger than that over smooth topography It is suggested that the high-resolution profiles from Argo floats and a more reasonable design of the inverse scheme will serve to understand mixing processes.
基金supported by the National Natural Science Foundation of China(Grant Nos.11974173 and 11774158)the HPC center of Nanjing University。
文摘Protein XPA plays critical roles in nucleotide excision repair pathway.Recent experimental work showed that the functional dynamics of XPA involves the one-dimensional diffusion along DNA to search the damage site.Here,we investigate the involved dynamical process using extensive coarse-grained molecular simulations at various salt concentrations.The results demonstrated strong salt concentration dependence of the diffusion mechanisms.At low salt concentrations,the one-dimensional diffusion with rotational coupling is the dominant mechanism.At high salt concentrations,the diffusion by three-dimensional mechanism becomes more probable.At wide range of salt concentrations,the residues involved in the DNA binding are similar and the one-dimensional diffusion of XPA along DNA displays sub-diffusive feature.This sub-diffusive feature is tentatively attributed to diverse strengths of XPA-DNA interactions.In addition,we showed that both binding to DNA and increasing salt concentration tend to stretch the conformation of the XPA,which increases the exposure extent of the sites for the binding of other repair proteins.
文摘This paper describes an accurate method of approximating the moments of the first-passage time for the birth and death Gross National Product GNP diffusion process when the GNP is a determined value or constant absorbing barrier. This was done by approximating the differential equations by equivalent difference equations.
文摘This article studies the optimal proportional reinsurance and investment problem under a constant elasticity of variance （CEV） model. Assume that the insurer＇s surplus process follows a jump-diffusion process, the insurer can purchase proportional reinsurance from the reinsurer via the variance principle and invest in a risk-free asset and a risky asset whose price is modeled by a CEV model. The diffusion term can explain the uncertainty associated with the surplus of the insurer or the additional small claims. The objective of the insurer is to maximize the expected exponential utility of terminal wealth. This optimization problem is studied in two cases depending on the diffusion term＇s explanation. In all cases, by using techniques of stochastic control theory, closed-form expressions for the value functions and optimal strategies are obtained.
基金The first author would 5ke to thank Prof. Server Martfnez for his kind hospitality during a visit to the CMM of Universidad de Chile, where part of this work was done. The authors also sincerely thank the referees for helpful comments. This work was supported by the National Natural Science Foundation of China （Grant No. 11371301） and Hunan Provincial Innovation Foundation For Postgraduate （Grant No. CX2015B203）.
文摘We study quasi-stationarity for one-dimensional diffusions killed at 0, when 0 is a regular boundary and ＋∞ is an entrance boundary. We give a necessary and sufficient condition for the existence of exactly one quasistationary distribution, and we also show that this distribution attracts all initial distributions.
文摘In this paper new diffuse solar radiation equations were established for Antalya,Turkey.For this purpose current equations from the literature which were functions of the clearness index and/or the sunshine fraction were examined.Nine(9)equations were selected to determine the regression constants of the new equations.In conclusion the best equation among the new equations was introduced on the basis of different statistical indicators.
