Three kinds of thermochromic materials(DC8,DC12,DC16)were synthesized by linking the rigid 1,4-bis[2-(4-pyridyl)ethenyl]-benzene(bpeb)with different lengths of alkyl chains.They exhibit remarkable fluorescent color ch...Three kinds of thermochromic materials(DC8,DC12,DC16)were synthesized by linking the rigid 1,4-bis[2-(4-pyridyl)ethenyl]-benzene(bpeb)with different lengths of alkyl chains.They exhibit remarkable fluorescent color changes under the irradiation of 365 nm light with elevating temperature,which is supposed to be caused by the transition between the crystal state and the amorphous state.Interestingly,the DC16 solid also has a photochromic character.It should be noticed that the phase transition temperatures of three materials measured by differential scanning calorimetry are higher than those of the fluorescence color changes during the heating process.Thus,the allochroic effect is attributed to the synergistic effect of both heating and photo-inducement(365 nm).Ethanol can turn the heated powder into the initial crystal again which indicates that their thermochromic behavior is reversible and makes the fluorescence recover.展开更多
AIM: To investigate the relationship between Fas gene expression and calcium influx change in peroxide-induced apoptotic hepatocytes and the possible molecular mechanism of Rxa in protecting hepatocytes.METHODS: Singl...AIM: To investigate the relationship between Fas gene expression and calcium influx change in peroxide-induced apoptotic hepatocytes and the possible molecular mechanism of Rxa in protecting hepatocytes.METHODS: Single-cell Fas mRNA expression in H2O2-exposed L02 hepatocytes with or without treatment of Rxa,an extract from an anti-peroxidant, Radix Salviae Miltiorrhizae,was determined by all-cell patch clamp and single-cell reverse transcriptase polymerase chain reaction (RT-PCR). Transient calcium influx change ([Ca2+]i) in the cells was evaluated with all-cell patch clamp micro-fluorescence single-cytosolic free Ca2+ concentration technique. Fas protein expression, early apoptotic index (annexin-V+) and cell membrane change inthe cells were evaluated by immunohistochemistry, flow cytometry (FCM) and scan electron microscopy respectively.RESULTS: In cells exposed to H2O2 for 2 h, the specific lane for Fas mRNA was vivid on electrophoresis, with increased Fas protein expression, [Ca2+]i (from 143.66±34.21 to 1115.28±227.16), annexin-V+ index (from 4.00±0.79 to 16.18±0.72) and membrane vesicle formation. However, in cells exposed to H2O2 but pre-treated with Rxa, there was no increase in Fas mRNA or protein expression and [Ca2+]i (103.56±28.92). Annexin-V+ index (8.92±1.44) was lower than the controls (P<0.01), and the cell membrane was intact.CONCLUSION: H2O2 induces apoptosis of L02 cells by increasing cytosolic [Ca2+]i, and inducing Fas mRNA and protein expression. Rxa protects the L02 cells from apoptosis through anti-peroxidation, inhibition of calcium overloading and prevention of the activation of cytosolic Fas signal pathway.展开更多
The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical ...The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.展开更多
This work aims to provide a relationship of how the key operational variables of frother type and impeller speed affect the size of bubble (D32). The study was performed using pilot-scale equipment (0.8 m^3) that ...This work aims to provide a relationship of how the key operational variables of frother type and impeller speed affect the size of bubble (D32). The study was performed using pilot-scale equipment (0.8 m^3) that is up to two orders of magnitude larger than equipment used for studies performed to date by others, and incorporated the key process variables of frother type and impeller speed. The results show that each frother family exhibits a unique CCC95-HLB relationship dependent on n (number of C-atoms in alkyl group) and m (number of propylene oxide group). Empirical models were developed to predict CCC95 from HLB associated with other two parameters a and ft. The impeller speed-bubble size tests show that D32 is unaffected by increased impeller tip speed across the range of 4.6 to 9.2 m/s (representing the industrial operating range), although D32 starts to increase below 4.6 m/s. The finding is valid for both coalescing and non-coalescing conditions. The results suggest that the bubble size and bubble size distribution (BSD) being created do not change with increasing impeller speed in the quiescent zone of the flotation.展开更多
In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group (DMRG) algorithm. Effect of the intra-ehain next-neares...In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group (DMRG) algorithm. Effect of the intra-ehain next-nearest- neighbor (NNN) super-exchange interaction is investigated in detail and the order parameters are calculated to detect the emergence of the dimerized phases. We find that the intra-chain NNN interaction plays a key role in inducing dimerized phases.展开更多
Musical analysis enables us to study the various elements of a musical work, for example texture, m dynamics, or harmony (including tonality). Thanks to musical analysis we are able to trace the compos technique, or...Musical analysis enables us to study the various elements of a musical work, for example texture, m dynamics, or harmony (including tonality). Thanks to musical analysis we are able to trace the compos technique, or assess the artistic value of given work. In addition to traditional, descriptive methods of e it ody, onal music analysis, we can observe in 20th century the development of methods based on science (mathematics, otherwise statistics). Such methodologies allow us to obtain a strict understanding of the structure of musical pieces Applying mathematical methods for musical analysis seems very reasonable in relation to the output of Frederic Chopin, due to large originality of the elements of musical pieces of this composer. Present paper was written as a result of research related to the applying of numerical method of analysis for exploring the tonal structure of Chopin's works. The author's research method enables a strict analysis of the chord's domination that can be classified under given key (range)--taking into consideration the harmonic functions. By the method of analysis we can get charts that depict whole diatonic vertical music material of the given piece. The main objective of the present study is to describe observations on the high uniqueness in the tonal construction of selected Chopin's mazurkas, especially, when compared to the miniatures of other composers of the first half of the 19th century and previously analyzed Chopin's pieces: etudes, preludes, and songs.展开更多
Parabolic through concentrators and parabolic dish concentrators followed by a PVR (pressurized volumetric receiver) are proposed, studying the performance behavior of a RCBC (regenerative closed Brayton cycle) op...Parabolic through concentrators and parabolic dish concentrators followed by a PVR (pressurized volumetric receiver) are proposed, studying the performance behavior of a RCBC (regenerative closed Brayton cycle) operating with helium or hydrogen. A pressurized gas such as helium circulates along the volumetric receiver, capturing the concentrated thermal solar energy to be further converted into electric power via a thermal cycle. The overall efficiency of the plant has been computed under variable parameters to determine the operating conditions for which efficiency and specific power are acceptable. As consequence of the proposed analysis, it is concluded that direct coupling between volumetric receivers and thermal engines renders high efficiency while avoiding an intermediate heat transfer medium.展开更多
At the level of the reading of contemporary literature, value identity in China is facing unprecedented challenges, particularly in the new century. New groups of writers and new writing styles are constantly springin...At the level of the reading of contemporary literature, value identity in China is facing unprecedented challenges, particularly in the new century. New groups of writers and new writing styles are constantly springing up and existing theoretical criticism has been attacked and torn apart, with the result that it has often lost its voice. With the rapid growth of online literature, the influence of non-mainstream literature in the domain of literary reading and consumption is increasing. Consequently, the above-mentioned problem is evolving into a new contradiction, i.e. a lack of mutual understanding and tolerance with regard to reading. In the past decade, an enormous number of novels have come out online, falling into over twenty categories. This paper takes into account both chronology and type of writing in selecting for review ten outstanding works of different genres from the last decade, stressing the aesthetic qualities and distinctive styles that differentiate them from their print counterparts.展开更多
We introduce a completely different method to calculate the evolution of a spin interacting with a sufficient large spin bath,especially suitable for treating the central spin model in a quantum dot(QD).With only an a...We introduce a completely different method to calculate the evolution of a spin interacting with a sufficient large spin bath,especially suitable for treating the central spin model in a quantum dot(QD).With only an approximation on the envelope of central spin,the symmetry can be exploited to reduce a huge Hilbert space which cannot be calculated with computers to many small ones which can be solved exactly.This method can be used to calculate spin-bath evolution for a spin bath containing many(say,1000)spins,without a perturbative limit such as strong magnetic field condition,and works for long-time regime with sufficient accuracy.As the spin-bath evolution can be calculated for a wide range of time and magnetic field,an optimal dynamic of spin flip-flop can be found,and more sophisticated approaches to achieve extremely high polarization of nuclear spins in a QD could be developed.展开更多
We investigate here various kinds of semi-product subgroups of Poincar6 group in the scheme of Cohen-Glashow's very special relativity along the deformation approach by Gibbons- Gomis-Pope. For each proper Poincar6 s...We investigate here various kinds of semi-product subgroups of Poincar6 group in the scheme of Cohen-Glashow's very special relativity along the deformation approach by Gibbons- Gomis-Pope. For each proper Poincar6 subgroup which is a semi-product of proper lorentz group with the spacetime translation group T(4), we investigate all possible deformations and obtain all the possible natural representations inherited from the 5 - d representation of Poincar6 group. We find from the obtained natural representation that rotation operation may have additional accompanied scale transformation when the original Lorentz subgroup is deformed and the boost operation gets the additional accompanied scale transformation in all the deformation cases. The additional accompanied scale transformation has a strong constrain on the possible invariant metric function of the corresponding geometry and the field theories in the spacetime with the corresponding geometry.展开更多
Stimulus-responsive energy storage devices,which can respond to external stimuli,such as heat,pH,moisture,pressure,or electric field,have recently attracted intensive attention,aiming at the ever-increasing demand for...Stimulus-responsive energy storage devices,which can respond to external stimuli,such as heat,pH,moisture,pressure,or electric field,have recently attracted intensive attention,aiming at the ever-increasing demand for safe batteries and smart electronics.The most typical stimulus-responsive materials are polymers that can change their conformation by forming and destroying secondary forces,including hydrogen bonds and electrostatic interactions in response to external stimuli,accompanied by changes in the intrinsic properties such as conductivity and hydrophobicity.Although the applications of stimulus-responsive functions in rechargeable batteries are still in the early stage because of the complexity and compatibility of battery architectures,many new concepts of regulating the polymer structures upon applications of stimuli have already been developed.In this review,we discuss the recent progress of stimulus-responsive polymers on energy storage devices featuring thermal protection and intelligent scenarios,with a focus on the detailed structural transformations of polymers under a given stimulus and the corresponding changes in battery performance.Finally,we present perspectives on the current limitations and future research directions of stimulus-responsive polymers for energy storage devices.展开更多
In this paper, the robustness of the orbit structure is investigated for a partially hyperbolic endomorphism f on a compact manifold M. It is first proved that the dynamical structure of its orbit space (the inverse ...In this paper, the robustness of the orbit structure is investigated for a partially hyperbolic endomorphism f on a compact manifold M. It is first proved that the dynamical structure of its orbit space (the inverse limit space) M^f of f is topologically quasi-stable under C^0-small perturbations in the following sense: For any covering endomorphism g C^0-close to f, there is a continuous map φ from M^9 to Π-∞^∞ M such that for any {yi}i∈z∈φ(M^9), yi+1 and f(yi) differ only by a motion along the center direction. It is then proved that f has quasi-shadowing property in the following sense: For any pseudo-orbit {xi}i∈z, there is a sequence of points {yi}i∈z tracing it, in which yi+1 is obtained from f(yi) by a motion along the center direction.展开更多
Molecular dynamic simulations are performed to study the nanoscratching behavior of polymers.The effects of scratching depth,scratching velocity and indenter/polymer interaction strength are investigated.It is found t...Molecular dynamic simulations are performed to study the nanoscratching behavior of polymers.The effects of scratching depth,scratching velocity and indenter/polymer interaction strength are investigated.It is found that polymer material in the scratching zone around the indenter can be removed in a ductile manner as the local temperature in the scratching zone exceeds glass transition temperature Tg.The recovery of polymer can be more significant when the temperature approaches or exceeds Tg.The tangential force,normal force and friction coefficient increase as the scratching depth increases.A larger scratching velocity leads to more material deformation and higher pile-up.The tangential force and normal force are larger for a larger scratching velocity whereas the friction coefficient is almost independent of the scratching velocities studied.It is also found that stronger indenter/polymer interaction strength results in a larger tangential force and friction coefficient.展开更多
Up to now the chirality is seldom studied in the diluted spin glass although many investigations have been performed on the site-ordered Edwards-Anderson model. By simulation, we investigate the dynamicaJ properties o...Up to now the chirality is seldom studied in the diluted spin glass although many investigations have been performed on the site-ordered Edwards-Anderson model. By simulation, we investigate the dynamicaJ properties of both the spin-glass and the chiral-glass phases in a diluted dipolar system, which was manifested to have a spin-glass transition by recent numerical study. By scaling we find that both phases have the same aging behavior and closer aging parameterμ. Similarly, the domains grow in the same way and both phases have a closer barrier exponent g2. It means that both the spins and the chirality have the same dynamical properties and they may freeze at the same temperature.展开更多
基金supported by the National Natural Science Foundation of China(No.21573092,No.21573087 and No.21873039)。
文摘Three kinds of thermochromic materials(DC8,DC12,DC16)were synthesized by linking the rigid 1,4-bis[2-(4-pyridyl)ethenyl]-benzene(bpeb)with different lengths of alkyl chains.They exhibit remarkable fluorescent color changes under the irradiation of 365 nm light with elevating temperature,which is supposed to be caused by the transition between the crystal state and the amorphous state.Interestingly,the DC16 solid also has a photochromic character.It should be noticed that the phase transition temperatures of three materials measured by differential scanning calorimetry are higher than those of the fluorescence color changes during the heating process.Thus,the allochroic effect is attributed to the synergistic effect of both heating and photo-inducement(365 nm).Ethanol can turn the heated powder into the initial crystal again which indicates that their thermochromic behavior is reversible and makes the fluorescence recover.
基金Supported by National Natural Science Fundation of China, No.39770938Whole Army Medical Scientific Research Task during the Fifteen the Five-year Plan, No. 01MA040
文摘AIM: To investigate the relationship between Fas gene expression and calcium influx change in peroxide-induced apoptotic hepatocytes and the possible molecular mechanism of Rxa in protecting hepatocytes.METHODS: Single-cell Fas mRNA expression in H2O2-exposed L02 hepatocytes with or without treatment of Rxa,an extract from an anti-peroxidant, Radix Salviae Miltiorrhizae,was determined by all-cell patch clamp and single-cell reverse transcriptase polymerase chain reaction (RT-PCR). Transient calcium influx change ([Ca2+]i) in the cells was evaluated with all-cell patch clamp micro-fluorescence single-cytosolic free Ca2+ concentration technique. Fas protein expression, early apoptotic index (annexin-V+) and cell membrane change inthe cells were evaluated by immunohistochemistry, flow cytometry (FCM) and scan electron microscopy respectively.RESULTS: In cells exposed to H2O2 for 2 h, the specific lane for Fas mRNA was vivid on electrophoresis, with increased Fas protein expression, [Ca2+]i (from 143.66±34.21 to 1115.28±227.16), annexin-V+ index (from 4.00±0.79 to 16.18±0.72) and membrane vesicle formation. However, in cells exposed to H2O2 but pre-treated with Rxa, there was no increase in Fas mRNA or protein expression and [Ca2+]i (103.56±28.92). Annexin-V+ index (8.92±1.44) was lower than the controls (P<0.01), and the cell membrane was intact.CONCLUSION: H2O2 induces apoptosis of L02 cells by increasing cytosolic [Ca2+]i, and inducing Fas mRNA and protein expression. Rxa protects the L02 cells from apoptosis through anti-peroxidation, inhibition of calcium overloading and prevention of the activation of cytosolic Fas signal pathway.
基金Project supported by the Science Foundation of Shanghai Municipal Commission of Education (Grant No.98AJ01)the Natural Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No.03ZR14032)
文摘The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.
基金Project supported by the Collaborative Research and Development Program of NSERC(Natural Sciences and Engineering Research Council of Canada) with Industrial Sponsorship from Vale,Teck Cominco,Xstrata Process Support,Agnico-Eagle,Shell Canada,Barrick Gold,COREM,SGS Lakefield Research and Flottec
文摘This work aims to provide a relationship of how the key operational variables of frother type and impeller speed affect the size of bubble (D32). The study was performed using pilot-scale equipment (0.8 m^3) that is up to two orders of magnitude larger than equipment used for studies performed to date by others, and incorporated the key process variables of frother type and impeller speed. The results show that each frother family exhibits a unique CCC95-HLB relationship dependent on n (number of C-atoms in alkyl group) and m (number of propylene oxide group). Empirical models were developed to predict CCC95 from HLB associated with other two parameters a and ft. The impeller speed-bubble size tests show that D32 is unaffected by increased impeller tip speed across the range of 4.6 to 9.2 m/s (representing the industrial operating range), although D32 starts to increase below 4.6 m/s. The finding is valid for both coalescing and non-coalescing conditions. The results suggest that the bubble size and bubble size distribution (BSD) being created do not change with increasing impeller speed in the quiescent zone of the flotation.
基金Supported by the Chinese National Science Foundation of China under Grant Nos.10874003,11074004,and 11047160Numerical Computation of This Work was Carried out on the Parallel Computer Cluster of Institute for Condensed Matter Physics(ICMP) at School of Physics,Peking University
文摘In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group (DMRG) algorithm. Effect of the intra-ehain next-nearest- neighbor (NNN) super-exchange interaction is investigated in detail and the order parameters are calculated to detect the emergence of the dimerized phases. We find that the intra-chain NNN interaction plays a key role in inducing dimerized phases.
文摘Musical analysis enables us to study the various elements of a musical work, for example texture, m dynamics, or harmony (including tonality). Thanks to musical analysis we are able to trace the compos technique, or assess the artistic value of given work. In addition to traditional, descriptive methods of e it ody, onal music analysis, we can observe in 20th century the development of methods based on science (mathematics, otherwise statistics). Such methodologies allow us to obtain a strict understanding of the structure of musical pieces Applying mathematical methods for musical analysis seems very reasonable in relation to the output of Frederic Chopin, due to large originality of the elements of musical pieces of this composer. Present paper was written as a result of research related to the applying of numerical method of analysis for exploring the tonal structure of Chopin's works. The author's research method enables a strict analysis of the chord's domination that can be classified under given key (range)--taking into consideration the harmonic functions. By the method of analysis we can get charts that depict whole diatonic vertical music material of the given piece. The main objective of the present study is to describe observations on the high uniqueness in the tonal construction of selected Chopin's mazurkas, especially, when compared to the miniatures of other composers of the first half of the 19th century and previously analyzed Chopin's pieces: etudes, preludes, and songs.
文摘Parabolic through concentrators and parabolic dish concentrators followed by a PVR (pressurized volumetric receiver) are proposed, studying the performance behavior of a RCBC (regenerative closed Brayton cycle) operating with helium or hydrogen. A pressurized gas such as helium circulates along the volumetric receiver, capturing the concentrated thermal solar energy to be further converted into electric power via a thermal cycle. The overall efficiency of the plant has been computed under variable parameters to determine the operating conditions for which efficiency and specific power are acceptable. As consequence of the proposed analysis, it is concluded that direct coupling between volumetric receivers and thermal engines renders high efficiency while avoiding an intermediate heat transfer medium.
文摘At the level of the reading of contemporary literature, value identity in China is facing unprecedented challenges, particularly in the new century. New groups of writers and new writing styles are constantly springing up and existing theoretical criticism has been attacked and torn apart, with the result that it has often lost its voice. With the rapid growth of online literature, the influence of non-mainstream literature in the domain of literary reading and consumption is increasing. Consequently, the above-mentioned problem is evolving into a new contradiction, i.e. a lack of mutual understanding and tolerance with regard to reading. In the past decade, an enormous number of novels have come out online, falling into over twenty categories. This paper takes into account both chronology and type of writing in selecting for review ten outstanding works of different genres from the last decade, stressing the aesthetic qualities and distinctive styles that differentiate them from their print counterparts.
基金supported by the National Basic Research Program of China(Grant Nos.2011CBA00300 and 2011CBA00301)the National Natural Science Foundation of China(Grant No.61033001)the Chinese Academy of Science
文摘We introduce a completely different method to calculate the evolution of a spin interacting with a sufficient large spin bath,especially suitable for treating the central spin model in a quantum dot(QD).With only an approximation on the envelope of central spin,the symmetry can be exploited to reduce a huge Hilbert space which cannot be calculated with computers to many small ones which can be solved exactly.This method can be used to calculate spin-bath evolution for a spin bath containing many(say,1000)spins,without a perturbative limit such as strong magnetic field condition,and works for long-time regime with sufficient accuracy.As the spin-bath evolution can be calculated for a wide range of time and magnetic field,an optimal dynamic of spin flip-flop can be found,and more sophisticated approaches to achieve extremely high polarization of nuclear spins in a QD could be developed.
文摘We investigate here various kinds of semi-product subgroups of Poincar6 group in the scheme of Cohen-Glashow's very special relativity along the deformation approach by Gibbons- Gomis-Pope. For each proper Poincar6 subgroup which is a semi-product of proper lorentz group with the spacetime translation group T(4), we investigate all possible deformations and obtain all the possible natural representations inherited from the 5 - d representation of Poincar6 group. We find from the obtained natural representation that rotation operation may have additional accompanied scale transformation when the original Lorentz subgroup is deformed and the boost operation gets the additional accompanied scale transformation in all the deformation cases. The additional accompanied scale transformation has a strong constrain on the possible invariant metric function of the corresponding geometry and the field theories in the spacetime with the corresponding geometry.
基金financially supported by the National Key R&D Program of China(2017YFE0127600)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA22010600)+4 种基金the National Natural Science Foundation of China(21975271)the Key-Area Research and Development Program of Guangdong Province(2020B090919005)Shandong Natural Science Foundation(ZR2020ZD07 and ZR2021QB106)the financial support from the Youth Innovation Promotion Association of CAS(2019214)Shandong Energy Institute(SEI 1202127)。
文摘Stimulus-responsive energy storage devices,which can respond to external stimuli,such as heat,pH,moisture,pressure,or electric field,have recently attracted intensive attention,aiming at the ever-increasing demand for safe batteries and smart electronics.The most typical stimulus-responsive materials are polymers that can change their conformation by forming and destroying secondary forces,including hydrogen bonds and electrostatic interactions in response to external stimuli,accompanied by changes in the intrinsic properties such as conductivity and hydrophobicity.Although the applications of stimulus-responsive functions in rechargeable batteries are still in the early stage because of the complexity and compatibility of battery architectures,many new concepts of regulating the polymer structures upon applications of stimuli have already been developed.In this review,we discuss the recent progress of stimulus-responsive polymers on energy storage devices featuring thermal protection and intelligent scenarios,with a focus on the detailed structural transformations of polymers under a given stimulus and the corresponding changes in battery performance.Finally,we present perspectives on the current limitations and future research directions of stimulus-responsive polymers for energy storage devices.
基金supported by the National Natural Science Foundation of China(No.11371120)the High-level Personnel for Institutions of Higher Learning in Hebei Province(No.GCC2014052)the Natural Science Foundation of Hebei Province(No.A2013205148)
文摘In this paper, the robustness of the orbit structure is investigated for a partially hyperbolic endomorphism f on a compact manifold M. It is first proved that the dynamical structure of its orbit space (the inverse limit space) M^f of f is topologically quasi-stable under C^0-small perturbations in the following sense: For any covering endomorphism g C^0-close to f, there is a continuous map φ from M^9 to Π-∞^∞ M such that for any {yi}i∈z∈φ(M^9), yi+1 and f(yi) differ only by a motion along the center direction. It is then proved that f has quasi-shadowing property in the following sense: For any pseudo-orbit {xi}i∈z, there is a sequence of points {yi}i∈z tracing it, in which yi+1 is obtained from f(yi) by a motion along the center direction.
基金supported by the National Natural Science Foundation of China (Grant No.90923038)the National Basic Research Program of China (Grant No.2011CB706703)+1 种基金"111"project (Grant No.B07014)by the State Administration of Foreign Experts Affairs and the Ministry of Education of China
文摘Molecular dynamic simulations are performed to study the nanoscratching behavior of polymers.The effects of scratching depth,scratching velocity and indenter/polymer interaction strength are investigated.It is found that polymer material in the scratching zone around the indenter can be removed in a ductile manner as the local temperature in the scratching zone exceeds glass transition temperature Tg.The recovery of polymer can be more significant when the temperature approaches or exceeds Tg.The tangential force,normal force and friction coefficient increase as the scratching depth increases.A larger scratching velocity leads to more material deformation and higher pile-up.The tangential force and normal force are larger for a larger scratching velocity whereas the friction coefficient is almost independent of the scratching velocities studied.It is also found that stronger indenter/polymer interaction strength results in a larger tangential force and friction coefficient.
基金Supported by National Natural Science Foundation of China under Grant Nos.11247428,61274101Natural Science Foundation of Liaoning Province under Grant No.20121078
文摘Up to now the chirality is seldom studied in the diluted spin glass although many investigations have been performed on the site-ordered Edwards-Anderson model. By simulation, we investigate the dynamicaJ properties of both the spin-glass and the chiral-glass phases in a diluted dipolar system, which was manifested to have a spin-glass transition by recent numerical study. By scaling we find that both phases have the same aging behavior and closer aging parameterμ. Similarly, the domains grow in the same way and both phases have a closer barrier exponent g2. It means that both the spins and the chirality have the same dynamical properties and they may freeze at the same temperature.