Background:The phenomenon of academic anxiety has been demonstrated to exert a considerable influence on students’academic engagement,leading to the emergence of a phenomenon known as“learned helplessness”and under...Background:The phenomenon of academic anxiety has been demonstrated to exert a considerable influence on students’academic engagement,leading to the emergence of a phenomenon known as“learned helplessness”and undermining the selfconfidence and motivation of high school students.Using acceptance-rejection theory,this study elucidated how a rejective parenting style affects Chinese high school students’academic anxiety and explored the urban-rural heterogeneity of this relationship.Methods:Data were analyzed using a stratified whole-cluster random sampling method.There are a total of 30,000 high school students in the three regions of northern and central China(from Shanxi,Hebei and Henan).A sample of 2286 high school students aged 14–19 years was ultimately selected from 2760 respondents for this investigation,which was conducted at the beginning of the 2023 school year.Pearson correlation,ordinary least squares(OLS)regression analysis,path analysis,and Fisher’s permutation test(FPT)were used to examine the effects of rejective parenting style on high school students’academic anxiety.Results:Results indicated a significant positive predictive effect between rejective parenting style and academic anxiety among high school students(β=0.815,t=116.211,p<0.001).Students’self-concept was significantly positively related to positive coping style(β=0.424,t=21.208,p<0.001)and chain-mediated this relationship.Therefore,this parenting style may indirectly mitigate academic anxiety through these mediators.The study also found that the effect of rejective parenting style on academic anxiety varied by students’residential background and was more pronounced in urban areas(0.226)than in rural areas(0.130).Conclusion:The research underscores the imperative for Chinese families to reexamine their utilization of rejection parenting and to prioritize the cultivation of students’intrinsic attributes.These findings offer a theoretical framework and practical evidence for policymakers and educators to develop efficacious and targeted interventions.In particular,greater attention should be directed towards the discrepancies in the manifestation of emotional and academic anxiety between urban and rural students,and prompt guidance should be furnished.展开更多
Measuring bullwhip effect is useful for making better controls on production planning and enhancing the supply chain operating efficiency.First,this article establishes the comparative analysis model of bullwhip effec...Measuring bullwhip effect is useful for making better controls on production planning and enhancing the supply chain operating efficiency.First,this article establishes the comparative analysis model of bullwhip effect between(s,S)and Periodic Review(PR)inventory policy based on the quantitative bullwhip effect model under different inventories.Then,the impacts of lead time,inventory review time,autocorrelation coefficient,and the number of samples on the gap of bullwhip effect under(s,S)and PR IP are analyzed.The results show that bullwhip effect in PR is more intense than(s,S)inventory policy.Contractors should pay more attention to control bullwhip effect when adopting PR inventory policy to enhance the total operating efficiency of the engineering project supply chains.展开更多
The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction b...The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.展开更多
Through improvements on a fully commercial and automatic system measuring frequency andtemperature spectra of the complex elastic, dielectric, and piezoelectric constants of polymerfilms, the precision for measuring c...Through improvements on a fully commercial and automatic system measuring frequency andtemperature spectra of the complex elastic, dielectric, and piezoelectric constants of polymerfilms, the precision for measuring complex dielectric constants achieved 2‰ from original 1%.The complex dielectric constants of PVDF, VDF （95 ）/VF （5）, VDF （52）/TrFE （48） and VDF（47. 5）/TrFE（47. 5）/HeFP （5） over a range of-120-140℃, 10-2-10;Hz were measured bythe described system. The diminution of chain regularity due to 5mol% vinyl fluoride in the chainof PVDF led to disappearing of α-relaxation and increase in T;（3℃） of VDF （95）/VF （5）.Because of the spatial impediment of 5mol% HeFP in copolymer chain, the Curie point of VDF（52）/TrFE（48） decreased by 30℃ and T;by 3℃. The behavior of dielectric relaxation indicatedthat 5mol% vinyl fluoride and HeFP made the relaxation strength of noncrystalline regionreduced, the activation energy of local relaxation increased and the relaxation time prolonged respectively.展开更多
The magnetic properties of a mixed spin-2 and spin-1/2 ferromagnetic diamond chain are studied by effective-field theory and Monte Carlo（MC） simulation based on the Ising model.The temperature dependences of magneti...The magnetic properties of a mixed spin-2 and spin-1/2 ferromagnetic diamond chain are studied by effective-field theory and Monte Carlo（MC） simulation based on the Ising model.The temperature dependences of magnetization,magnetic susceptibility,internal energy,and specific heat are studied,respectively.The exchange interaction dependences of magnetization and the critical temperature are calculated by MC simulation.The changes of magnetization depending on the field increasing and then the field decreasing under steady-static conditions are also given.展开更多
This paper firstly introduces the value chain management thought,current situations of utilization,and connotation of mechanism for increasing effective inputs in urban agriculture through industrial value chain.On th...This paper firstly introduces the value chain management thought,current situations of utilization,and connotation of mechanism for increasing effective inputs in urban agriculture through industrial value chain.On the basis of basic idea of value chain management,this paper is to explore the mechanism for increasing effective inputs in urban agriculture through the value chain of urban agriculture linking with other industries.展开更多
A theoretical study on oligopeptide chains of glycine-alanine by density functional theory（DFT） is given in this paper. Raman spectra of the oligopeptide chains are examined. The geometric structures, frontier orbit...A theoretical study on oligopeptide chains of glycine-alanine by density functional theory（DFT） is given in this paper. Raman spectra of the oligopeptide chains are examined. The geometric structures, frontier orbital, energy gap, atomic charge distribution, density of states and chemical activity of the side chain are studied at the B3LYP/6-31G（d） level. Results show that, with the number of residues increasing, vibrations of typical functional groups present Raman frequency shift, and the energy gap is gradually reduced. The HOMO and LUMO focus on the amino and carboxyl at the ends of oligopeptides. It is helpful for oligopeptides to self-assemble into chains. In addition, different residues（glycine or alanine） at the ends of chains result in the even-odd effect of orbital energy in the growth process. The size effects of physical and chemical properties only exist when the oligopeptides are shorter, and the phenomenon disappeared as the chain continues to grow.展开更多
We investigate the quantum phase transition(QPT) and magnetocaloric effect(MCE) of a tetrameric chain with three-spin interaction using Green's function theory. The magnetization and gap analysis reveals a variety...We investigate the quantum phase transition(QPT) and magnetocaloric effect(MCE) of a tetrameric chain with three-spin interaction using Green's function theory. The magnetization and gap analysis reveals a variety of quantum phases tuned by magnetic field and three-spin interaction, which can open up an energy gap, giving rise to the occurrence of zero magnetization plateau. However, strong three-spin couplings causing strong frustration will destroy the intermediate 1/2 plateau with emergence of a new gapless phase between two cusps. It favors achieving an enhanced MCE at the critical fields, where the minima of isoentropes as well as the valley-peak structure of Gru¨neisen ratio, signaling the accumulation of entropy, lead to cooling via adiabatic(de)magnetization processes. It is also found that the temperature dependence of specific heat combined with Gru¨neisen ratio can testify various quantum phases explicitly.展开更多
Bullwhip effect is the most important factor considered in the supply chain management. It gets many scholars＇ attention that bullwhip effect has been restricting the development of the supply chain all the time. Inf...Bullwhip effect is the most important factor considered in the supply chain management. It gets many scholars＇ attention that bullwhip effect has been restricting the development of the supply chain all the time. Information Technology （IT） can reduce bullwhip effect by sharing the information among the enterprises in the supply chain.展开更多
Long-alkyl tail triphenylene （TP） side-chain liquid crystalline polymers （SCLCPs） with different spacer length （P-m-TP, m = 2, 3, 4, 6, 8, which is the number of carbon atom in the flexible alkyl spacers） have b...Long-alkyl tail triphenylene （TP） side-chain liquid crystalline polymers （SCLCPs） with different spacer length （P-m-TP, m = 2, 3, 4, 6, 8, which is the number of carbon atom in the flexible alkyl spacers） have been successfully synthesized via free radical polymerization. The differential scanning calorimetry （DSC）, polarized light microscopy （POM）, ultraviolet-visible spectroscopy （UV- Vis）, wide-angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） measurements were performed to investigate the influence of multiple effects on the self-organization behaviors of P-m-TP, including steric effect, decoupling effect and π-π stacking effect. The experimental results revealed that P-m-TP （m = 2, 3, 4） formed the columnar phase which was developed by the TP moieties and the main chain as a whole, suggesting that the side-chains had strong steric effect even though the number of spacer length （m） exceeded 4. In addition, the clearing points （Tis） of the polymers were above 300 ℃. When m = 6 and 8, the polymers displayed hexagonal columnar phase and exhibited the low Tis （91 and 80 ℃ respectively）, originating from the self-assembly of triphenylene due to the decoupling effect and π-π stacking effect. This work offers a viable and inspiring pathway to control the phase transition temperature and phase structure ofTP SCLCPs via simply tailoring the spacer length and increasing the alkyl tail length of TP.展开更多
Shorter product life cycles present new dressed in supply chain literature. This research challenges to managing production and logistics not adequately adaddresses issues pertaining to the management of supply chains...Shorter product life cycles present new dressed in supply chain literature. This research challenges to managing production and logistics not adequately adaddresses issues pertaining to the management of supply chains in a short life cycle environment. In this paper, we study the short life cycle environment; then we develop the ventory policy of the indirect manufacturer by explicitly using his demand us an output of the retailer＇s optimal inoptimal ordering policy. Finally, we also provide causes of the bullwhip effect in the context of short life cycle products.展开更多
The one-dimensional monoatomic lattice chain connected by nonlinear springs is investigated, and the asymptotic solution is obtained through the Lindstedt-Poincar′e perturbation method. The dispersion relation is der...The one-dimensional monoatomic lattice chain connected by nonlinear springs is investigated, and the asymptotic solution is obtained through the Lindstedt-Poincar′e perturbation method. The dispersion relation is derived with the consideration of both the nonlocal and the active control effects. The numerical results show that the nonlocal effect can effectively enhance the frequency in the middle part of the dispersion curve.When the nonlocal effect is strong enough, zero and negative group velocities will be evoked at different points along the dispersion curve, which will provide different ways of transporting energy including the forward-propagation, localization, and backwardpropagation of wavepackets related to the phase velocity. Both the nonlinear effect and the active control can enhance the frequency, but neither of them is able to produce zero or negative group velocities. Specifically, the active control enhances the frequency of the dispersion curve including the point at which the reduced wave number equals zero, and therefore gives birth to a nonzero cutoff frequency and a band gap in the low frequency range. With a combinational adjustment of all these effects, the wave propagation behaviors can be comprehensively controlled, and energy transferring can be readily manipulated in various ways.展开更多
Background and objective:Botulinum toxin type A(BoNT/A)is a metalloprotease that blocks synaptic transmission via the cleavage of a synaptosomal-associated protein of 25 kDa(SNAP-25).It has gained widespread use as a ...Background and objective:Botulinum toxin type A(BoNT/A)is a metalloprotease that blocks synaptic transmission via the cleavage of a synaptosomal-associated protein of 25 kDa(SNAP-25).It has gained widespread use as a treatment for cerebral palsy and skeletal muscle hypertrophy.In China,Chinese botulinum toxin type A(CBTX-A),a type of BoNT/A,is in widespread clinical use.However,the changes in the morphological and biochemical properties of treated muscles and in remote muscles from the CBTX-A injection site are relatively unknown.Therefore,we investigated the changes in histomorphology and myosin heavy chain(MyHC)isoform composition and distribution in rat gastrocnemius muscles after intramuscular injection of CBTX-A.Methods:The weakness of the injected muscles was assessed periodically to identify their functional deficiency.Muscle slices were stained with hematoxylin-eosin(HE)and adenosine triphosphatase(ATPase).MyHC isoform composition was analyzed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis(SDS-PAGE)to uncover changes in morphological and biochemical properties.Results:Our findings demonstrate that following injection of CBTX-A 5 U into rat gastrocnemius muscles,shifts in MyHC isoform composition emerged on the third day after injection and peaked in the fourth week.The composition remained distinctly different from that of the control group after the twelfth week.More specifically,there was a decrease in the proportion of the type IIb isoform and an increase in the proportions of type IIx,type IIa,and type I isoforms.Conclusions:Data revealed that CBTX-A led to a shift in MyHC composition towards slower isoforms and that the MyHC composition remained far from normal six months after a single injection.However,no noticeable remote muscle weakness was induced.展开更多
Elastic impedance inversion with high efficiency and high stability has become one of the main directions of seismic pre-stack inversion. The nonlinear elastic impedance inversion method based on a fast Markov chain M...Elastic impedance inversion with high efficiency and high stability has become one of the main directions of seismic pre-stack inversion. The nonlinear elastic impedance inversion method based on a fast Markov chain Monte Carlo （MCMC） method is proposed in this paper, combining conventional MCMC method based on global optimization with a preconditioned conjugate gradient （PCG） algorithm based on local optimization, so this method does not depend strongly on the initial model. It converges to the global optimum quickly and efficiently on the condition that effi- ciency and stability of inversion are both taken into consid- eration at the same time. The test data verify the feasibility and robustness of the method, and based on this method, we extract the effective pore-fluid bulk modulus, which is applied to reservoir fluid identification and detection, and consequently, a better result has been achieved.展开更多
In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial spillover effects and driving factors of carbon emission inten...In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial spillover effects and driving factors of carbon emission intensity in 283 Chinese cities from 1992 to 2013. The following results were obtained.(1) Nuclear density estimation shows that the overall average carbon intensity of cities in China has decreased, with differences gradually narrowing.(2) The spatial autocorrelation Moran's I index indicates significant spatial agglomeration of carbon emission intensity is gradually increasing; however, differences between regions have remained stable.(3) Spatial Markov chain analysis shows a Matthew effect in China's urban carbon emission intensity. In addition, low-intensity and high-intensity cities characteristically maintain their initial state during the transition period. Furthermore, there is a clear "Spatial Spillover" effect in urban carbon emission intensity and there is heterogeneity in the spillover effect in different regional contexts; that is, if a city is near a city with low carbon emission intensity, the carbon emission intensity of the first city has a higher probability of upward transfer, and vice versa.(4) Panel quantile results indicate that in cities with low carbon emission intensity, economic growth, technological progress, and appropriate population density play an important role in reducing emissions. In addition, foreign investment intensity and traffic emissions are the main factors that increase carbon emission intensity. In cities with high carbon intensity, population density is an important emission reduction factor, and technological progress has no significant effect. In contrast, industrial emissions, extensive capital investment, and urban land expansion are the main factors driving the increase in carbon intensity.展开更多
基金funded by the Key Discipline Construction Project of the Liaoning Provincial Social Science Planning Fund(grant ID:L24ZD042)。
文摘Background:The phenomenon of academic anxiety has been demonstrated to exert a considerable influence on students’academic engagement,leading to the emergence of a phenomenon known as“learned helplessness”and undermining the selfconfidence and motivation of high school students.Using acceptance-rejection theory,this study elucidated how a rejective parenting style affects Chinese high school students’academic anxiety and explored the urban-rural heterogeneity of this relationship.Methods:Data were analyzed using a stratified whole-cluster random sampling method.There are a total of 30,000 high school students in the three regions of northern and central China(from Shanxi,Hebei and Henan).A sample of 2286 high school students aged 14–19 years was ultimately selected from 2760 respondents for this investigation,which was conducted at the beginning of the 2023 school year.Pearson correlation,ordinary least squares(OLS)regression analysis,path analysis,and Fisher’s permutation test(FPT)were used to examine the effects of rejective parenting style on high school students’academic anxiety.Results:Results indicated a significant positive predictive effect between rejective parenting style and academic anxiety among high school students(β=0.815,t=116.211,p<0.001).Students’self-concept was significantly positively related to positive coping style(β=0.424,t=21.208,p<0.001)and chain-mediated this relationship.Therefore,this parenting style may indirectly mitigate academic anxiety through these mediators.The study also found that the effect of rejective parenting style on academic anxiety varied by students’residential background and was more pronounced in urban areas(0.226)than in rural areas(0.130).Conclusion:The research underscores the imperative for Chinese families to reexamine their utilization of rejection parenting and to prioritize the cultivation of students’intrinsic attributes.These findings offer a theoretical framework and practical evidence for policymakers and educators to develop efficacious and targeted interventions.In particular,greater attention should be directed towards the discrepancies in the manifestation of emotional and academic anxiety between urban and rural students,and prompt guidance should be furnished.
文摘Measuring bullwhip effect is useful for making better controls on production planning and enhancing the supply chain operating efficiency.First,this article establishes the comparative analysis model of bullwhip effect between(s,S)and Periodic Review(PR)inventory policy based on the quantitative bullwhip effect model under different inventories.Then,the impacts of lead time,inventory review time,autocorrelation coefficient,and the number of samples on the gap of bullwhip effect under(s,S)and PR IP are analyzed.The results show that bullwhip effect in PR is more intense than(s,S)inventory policy.Contractors should pay more attention to control bullwhip effect when adopting PR inventory policy to enhance the total operating efficiency of the engineering project supply chains.
基金Project(50673033) supported by the National Natural Science Foundation of China
文摘The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.
文摘Through improvements on a fully commercial and automatic system measuring frequency andtemperature spectra of the complex elastic, dielectric, and piezoelectric constants of polymerfilms, the precision for measuring complex dielectric constants achieved 2‰ from original 1%.The complex dielectric constants of PVDF, VDF （95 ）/VF （5）, VDF （52）/TrFE （48） and VDF（47. 5）/TrFE（47. 5）/HeFP （5） over a range of-120-140℃, 10-2-10;Hz were measured bythe described system. The diminution of chain regularity due to 5mol% vinyl fluoride in the chainof PVDF led to disappearing of α-relaxation and increase in T;（3℃） of VDF （95）/VF （5）.Because of the spatial impediment of 5mol% HeFP in copolymer chain, the Curie point of VDF（52）/TrFE（48） decreased by 30℃ and T;by 3℃. The behavior of dielectric relaxation indicatedthat 5mol% vinyl fluoride and HeFP made the relaxation strength of noncrystalline regionreduced, the activation energy of local relaxation increased and the relaxation time prolonged respectively.
基金Project supported by the Shanghai Leading Academic Disciplines Project,China (Grant No. T0104)the National Natural Science Foundation of China(Grant No. 10674092)
文摘The magnetic properties of a mixed spin-2 and spin-1/2 ferromagnetic diamond chain are studied by effective-field theory and Monte Carlo（MC） simulation based on the Ising model.The temperature dependences of magnetization,magnetic susceptibility,internal energy,and specific heat are studied,respectively.The exchange interaction dependences of magnetization and the critical temperature are calculated by MC simulation.The changes of magnetization depending on the field increasing and then the field decreasing under steady-static conditions are also given.
基金Supported by the Project of Tianjin Philosophy and Social Science Research
文摘This paper firstly introduces the value chain management thought,current situations of utilization,and connotation of mechanism for increasing effective inputs in urban agriculture through industrial value chain.On the basis of basic idea of value chain management,this paper is to explore the mechanism for increasing effective inputs in urban agriculture through the value chain of urban agriculture linking with other industries.
基金Supported by the National Natural Science Foundation of China(No.60878063)the Program from Traditional Chinese Medicine Bureau of Guangdong Province(No.2008233)
文摘A theoretical study on oligopeptide chains of glycine-alanine by density functional theory（DFT） is given in this paper. Raman spectra of the oligopeptide chains are examined. The geometric structures, frontier orbital, energy gap, atomic charge distribution, density of states and chemical activity of the side chain are studied at the B3LYP/6-31G（d） level. Results show that, with the number of residues increasing, vibrations of typical functional groups present Raman frequency shift, and the energy gap is gradually reduced. The HOMO and LUMO focus on the amino and carboxyl at the ends of oligopeptides. It is helpful for oligopeptides to self-assemble into chains. In addition, different residues（glycine or alanine） at the ends of chains result in the even-odd effect of orbital energy in the growth process. The size effects of physical and chemical properties only exist when the oligopeptides are shorter, and the phenomenon disappeared as the chain continues to grow.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11204157,11174179,11247020the China Three Gorges University Project KJ2011B068
文摘We investigate the quantum phase transition(QPT) and magnetocaloric effect(MCE) of a tetrameric chain with three-spin interaction using Green's function theory. The magnetization and gap analysis reveals a variety of quantum phases tuned by magnetic field and three-spin interaction, which can open up an energy gap, giving rise to the occurrence of zero magnetization plateau. However, strong three-spin couplings causing strong frustration will destroy the intermediate 1/2 plateau with emergence of a new gapless phase between two cusps. It favors achieving an enhanced MCE at the critical fields, where the minima of isoentropes as well as the valley-peak structure of Gru¨neisen ratio, signaling the accumulation of entropy, lead to cooling via adiabatic(de)magnetization processes. It is also found that the temperature dependence of specific heat combined with Gru¨neisen ratio can testify various quantum phases explicitly.
文摘Bullwhip effect is the most important factor considered in the supply chain management. It gets many scholars＇ attention that bullwhip effect has been restricting the development of the supply chain all the time. Information Technology （IT） can reduce bullwhip effect by sharing the information among the enterprises in the supply chain.
基金financially supported by the National Natural Science Foundation of China (No.21504075)Natural Science Foundation of Hunan Province (No.2017JJ3294)
文摘Long-alkyl tail triphenylene （TP） side-chain liquid crystalline polymers （SCLCPs） with different spacer length （P-m-TP, m = 2, 3, 4, 6, 8, which is the number of carbon atom in the flexible alkyl spacers） have been successfully synthesized via free radical polymerization. The differential scanning calorimetry （DSC）, polarized light microscopy （POM）, ultraviolet-visible spectroscopy （UV- Vis）, wide-angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） measurements were performed to investigate the influence of multiple effects on the self-organization behaviors of P-m-TP, including steric effect, decoupling effect and π-π stacking effect. The experimental results revealed that P-m-TP （m = 2, 3, 4） formed the columnar phase which was developed by the TP moieties and the main chain as a whole, suggesting that the side-chains had strong steric effect even though the number of spacer length （m） exceeded 4. In addition, the clearing points （Tis） of the polymers were above 300 ℃. When m = 6 and 8, the polymers displayed hexagonal columnar phase and exhibited the low Tis （91 and 80 ℃ respectively）, originating from the self-assembly of triphenylene due to the decoupling effect and π-π stacking effect. This work offers a viable and inspiring pathway to control the phase transition temperature and phase structure ofTP SCLCPs via simply tailoring the spacer length and increasing the alkyl tail length of TP.
文摘Shorter product life cycles present new dressed in supply chain literature. This research challenges to managing production and logistics not adequately adaddresses issues pertaining to the management of supply chains in a short life cycle environment. In this paper, we study the short life cycle environment; then we develop the ventory policy of the indirect manufacturer by explicitly using his demand us an output of the retailer＇s optimal inoptimal ordering policy. Finally, we also provide causes of the bullwhip effect in the context of short life cycle products.
基金Project supported by the National Natural Science Foundation of China(Nos.11532001and 11621062)the Fundamental Research Funds for the Central Universities of China(No.2016XZZX001-05)
文摘The one-dimensional monoatomic lattice chain connected by nonlinear springs is investigated, and the asymptotic solution is obtained through the Lindstedt-Poincar′e perturbation method. The dispersion relation is derived with the consideration of both the nonlocal and the active control effects. The numerical results show that the nonlocal effect can effectively enhance the frequency in the middle part of the dispersion curve.When the nonlocal effect is strong enough, zero and negative group velocities will be evoked at different points along the dispersion curve, which will provide different ways of transporting energy including the forward-propagation, localization, and backwardpropagation of wavepackets related to the phase velocity. Both the nonlinear effect and the active control can enhance the frequency, but neither of them is able to produce zero or negative group velocities. Specifically, the active control enhances the frequency of the dispersion curve including the point at which the reduced wave number equals zero, and therefore gives birth to a nonzero cutoff frequency and a band gap in the low frequency range. With a combinational adjustment of all these effects, the wave propagation behaviors can be comprehensively controlled, and energy transferring can be readily manipulated in various ways.
基金Project (No.491030-w10011) supported by the Zhejiang Provincial Natural Science Foundation of China
文摘Background and objective:Botulinum toxin type A(BoNT/A)is a metalloprotease that blocks synaptic transmission via the cleavage of a synaptosomal-associated protein of 25 kDa(SNAP-25).It has gained widespread use as a treatment for cerebral palsy and skeletal muscle hypertrophy.In China,Chinese botulinum toxin type A(CBTX-A),a type of BoNT/A,is in widespread clinical use.However,the changes in the morphological and biochemical properties of treated muscles and in remote muscles from the CBTX-A injection site are relatively unknown.Therefore,we investigated the changes in histomorphology and myosin heavy chain(MyHC)isoform composition and distribution in rat gastrocnemius muscles after intramuscular injection of CBTX-A.Methods:The weakness of the injected muscles was assessed periodically to identify their functional deficiency.Muscle slices were stained with hematoxylin-eosin(HE)and adenosine triphosphatase(ATPase).MyHC isoform composition was analyzed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis(SDS-PAGE)to uncover changes in morphological and biochemical properties.Results:Our findings demonstrate that following injection of CBTX-A 5 U into rat gastrocnemius muscles,shifts in MyHC isoform composition emerged on the third day after injection and peaked in the fourth week.The composition remained distinctly different from that of the control group after the twelfth week.More specifically,there was a decrease in the proportion of the type IIb isoform and an increase in the proportions of type IIx,type IIa,and type I isoforms.Conclusions:Data revealed that CBTX-A led to a shift in MyHC composition towards slower isoforms and that the MyHC composition remained far from normal six months after a single injection.However,no noticeable remote muscle weakness was induced.
基金the sponsorship of the National Basic Research Program of China (973 Program,2013CB228604,2014CB239201)the National Oil and Gas Major Projects of China (2011ZX05014-001-010HZ,2011ZX05014-001-006-XY570) for their funding of this research
文摘Elastic impedance inversion with high efficiency and high stability has become one of the main directions of seismic pre-stack inversion. The nonlinear elastic impedance inversion method based on a fast Markov chain Monte Carlo （MCMC） method is proposed in this paper, combining conventional MCMC method based on global optimization with a preconditioned conjugate gradient （PCG） algorithm based on local optimization, so this method does not depend strongly on the initial model. It converges to the global optimum quickly and efficiently on the condition that effi- ciency and stability of inversion are both taken into consid- eration at the same time. The test data verify the feasibility and robustness of the method, and based on this method, we extract the effective pore-fluid bulk modulus, which is applied to reservoir fluid identification and detection, and consequently, a better result has been achieved.
基金National Natural Science Foundation of China,No.41601151Natural Science Foundation of Guangdong Province,No.2016A030310149Pearl River S&T Nova Program of Guangzhou(201806010187)
文摘In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial spillover effects and driving factors of carbon emission intensity in 283 Chinese cities from 1992 to 2013. The following results were obtained.(1) Nuclear density estimation shows that the overall average carbon intensity of cities in China has decreased, with differences gradually narrowing.(2) The spatial autocorrelation Moran's I index indicates significant spatial agglomeration of carbon emission intensity is gradually increasing; however, differences between regions have remained stable.(3) Spatial Markov chain analysis shows a Matthew effect in China's urban carbon emission intensity. In addition, low-intensity and high-intensity cities characteristically maintain their initial state during the transition period. Furthermore, there is a clear "Spatial Spillover" effect in urban carbon emission intensity and there is heterogeneity in the spillover effect in different regional contexts; that is, if a city is near a city with low carbon emission intensity, the carbon emission intensity of the first city has a higher probability of upward transfer, and vice versa.(4) Panel quantile results indicate that in cities with low carbon emission intensity, economic growth, technological progress, and appropriate population density play an important role in reducing emissions. In addition, foreign investment intensity and traffic emissions are the main factors that increase carbon emission intensity. In cities with high carbon intensity, population density is an important emission reduction factor, and technological progress has no significant effect. In contrast, industrial emissions, extensive capital investment, and urban land expansion are the main factors driving the increase in carbon intensity.
