This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by time-modulated correlated coloured noise sources. The power spectrum and signal-to-noise ratio R of the laser intensity a...This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by time-modulated correlated coloured noise sources. The power spectrum and signal-to-noise ratio R of the laser intensity are calculated by the linear approximation. The effects caused by noise self-correlation time τ1, τ2 and cross-correlated time τ3 for stochastic resonance are analysed in two ways： τ1, τ2 and τ3 are taken to be the independent variables and the parameters respectively. The effects of the gain coefficient F and loss coefficient K on the stochastic resonance are also discussed. It is found that besides the presence of the standard form and the broad sense of stochastic resonance, the number of extrema in the curve of R versus K is reduced with the increase of the gain coefficient Г.展开更多
This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the def...This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the definition of Shannon＇s information entropy, the time dependence of entropy flux and entropy production can be calculated. The present results can be used to explain the extremal behaviour of time dependence of entropy flux and entropy production in view of the dissipative parameter γ of the system, coloured cross-correlation time τ and coloured cross-correlation strength λ.展开更多
It is shown how the cross-correlation time and strength of coloured cross-correlated white noises can set an upper bound for the time derivative of entropy in a nonequilibrium system. The value of upper bound can be c...It is shown how the cross-correlation time and strength of coloured cross-correlated white noises can set an upper bound for the time derivative of entropy in a nonequilibrium system. The value of upper bound can be calculated directly based on the Schwartz inequality principle and the Fokker-Planck equation of the dynamical system driven by coloured cross-correlated white noises. The present calculations can be used to interpret the interplay of the dissipative constant and cross-correlation time and strength of coloured cross-correlated white noises on the upper bound.展开更多
By adding frequency modulated signals to the intensity equation of gain noise model of the single-mode laser driven by two coloured noises which are correlated, this paper uses the linear approximation method to calcu...By adding frequency modulated signals to the intensity equation of gain noise model of the single-mode laser driven by two coloured noises which are correlated, this paper uses the linear approximation method to calculate the power spectrum and signal-to-noise ratio （SNR） of the laser intensity. The results show that the SNR appears typical stochastic resonance with the variation of intensity of the pump noise and quantum noise. As the amplitude of a modulated signal has effects on the SNR, it shows suppression, monotone increasing, stochastic resonance, and multiple stochastic resonance with the variation of the frequency of a carrier signal and modulated signal.展开更多
The phenomenon of stochastic resonance is investigated in an asymmetric bistable system with coloured noises. The approximate Fokker Planck equation is derived based on the Novikov theorem and the Fox approach. By app...The phenomenon of stochastic resonance is investigated in an asymmetric bistable system with coloured noises. The approximate Fokker Planck equation is derived based on the Novikov theorem and the Fox approach. By applying the two-state theory, the expression of the signal-to-noise ratio is obtained in the adiabatic limit. The effects of the noise parameters on signal-to-ratio are discussed. It is found that the stochastic resonance phenomena appear in most cases and disappear in some special cases.展开更多
In this paper, we studied the effect of Gaussian coloured noise on the formation and instability of spiral waves described by one class of modified FitzHugh Nagumo equation. It was found that Gaussian coloured noise p...In this paper, we studied the effect of Gaussian coloured noise on the formation and instability of spiral waves described by one class of modified FitzHugh Nagumo equation. It was found that Gaussian coloured noise plays a constructive role in the formation, transition and instability of spiral wave. Too weak or too strong noise may act against the formation of spiral waves. At a certain noise level, spiral wave is maintained in a medium, in which spiral wave cannot be observed in the absence of the noise. It is difficult to make a stable spiral wave into unstable state by Gaussian coloured noise, unless the noise level is very high. The parameter regions of Gaussian coloured noise for spiral forming and spiral instability were given and discussed with numerical simulations.展开更多
Aspect-oriented modeling can uncover potential design faults, yet most existing work fails to achieve both separation and composition in a natural and succinct way. This study presents an aspect-oriented modeling and ...Aspect-oriented modeling can uncover potential design faults, yet most existing work fails to achieve both separation and composition in a natural and succinct way. This study presents an aspect-oriented modeling and analysis approach with hierarchical Coloured Petri Nets(HCPN). HCPN has sub-models and well-defined semantics combining a set of submodels. These two characteristics of HCPN are nicely integrated into aspect oriented modeling. Submodels are used to model aspects while the combination mechanism contributes to aspects weaving. Furthermore, the woven aspect oriented HCPN model can be simulated and analyzed by the CPN Tools. A systematic web application case study is conducted. The results show the system original properties are satisfied after weaving aspects and all design flaws are revealed. As such, the approach can support web application design and analysis in an aspect-oriented fashion concisely and effectively.展开更多
Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European ma...Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European market.Later,emeralds from Colombia were shipped via the ocean to the Old World.展开更多
The diffusion in a harmonic oscillator driven by coloured noises ξ（t） and η（t） with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expre...The diffusion in a harmonic oscillator driven by coloured noises ξ（t） and η（t） with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1） The curves of d versus noise intensity D and d versus noises cross-correlation time z3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient A of the two Ornstein-Uhlenbeck （O-U） noises. 2） Changing the value of T3, the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3） Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model.展开更多
This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By d...This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By directly simulating the Langevin Equation, the following results are obtained. （1） The multiplicative coloured noise dominates, however, the effect of the additive coloured noise is not neglected in the practical gene selection process. The selection rate μ decides that the selection is propitious to gene A haploid or gene B haploid. （2） The additive coloured noise intensity and the correlation time τ2 play opposite roles. It is noted that α and τ2 can not separate the single peak, while can make the peak disappear and ^-2 can make the peak be sharp. （3） The multiplicative coloured noise intensity D and the correlation time τ1 can induce phase transition, at the same time they play opposite roles and the reentrance phenomenon appears. In this case, it is easy to select one type haploid from the group with increasing D and decreasing τ1.展开更多
The effect of heat treatment on the surface colour and hygro- scopic properties of pine wood were investigated in this study. Boards of Scots pine wood （Pinus sylvestris L.） were subjected to thermal treatment at 20...The effect of heat treatment on the surface colour and hygro- scopic properties of pine wood were investigated in this study. Boards of Scots pine wood （Pinus sylvestris L.） were subjected to thermal treatment at 200℃, for 4, 6, and 8 h. The change of equilibrium moisture content and density values of the specimens in order to facilitate the understand- ing of the treated material behavior. The colour parameters L＊ a＊ and b＊, used to depict the total colour change （dE） of wood surface, were shown to change proportionally to the treatment intensity. Moreover, swelling in the tangential and radial directions and absorption of the specimens ap- peared to be enhanced in great extent by the thermal treatment process. The mean value of swelling percentage in the tangential direction de- creased 10.26%, 17.22%, and 19.60% for specimens treated for 4, 6, and 8 h, respectively, referring to the final measurement after 72 h of immer- sion. In radial direction, mean value of swelling percentage decreased 19.56%, 32.75%, and 34.65% for treated for 4, 6 and 8 h, respectively, after 72 h immersion, which attests the decrease in swelling and im- provement in the hygroscopic behavior of Scots pine wood.展开更多
The aging process of pure copper precursors and copper-zinc binary precursorswere studied by XRD, TG-DTG and TPR techniques. The catalytic activity and stability of CuO/ZnOwere tested using fixed-bed flow reactor, and...The aging process of pure copper precursors and copper-zinc binary precursorswere studied by XRD, TG-DTG and TPR techniques. The catalytic activity and stability of CuO/ZnOwere tested using fixed-bed flow reactor, and the physical properties of the catalysts and Cuspecies were characterized with N_2 adsorption and N_2O passivation method, respectively. For theCu-Zn binary system prepared at the precipitating condition of pH=8.0 and temperature=80℃, theinitial phase was a mixture of copper nitrate hydroxide Cu_2(NO_3)(OH)_3, georgeite and hydrozinciteZn_5(CO_3)_2(OH)_6. By increasing the duration of its aging time, the phase of Cu_2(NO_3)(OH)_2first transited to georgeite, and then interdiffused into Zn_5(CO_3)_2(OH)_6 and resulted in two newphases: rosasite (Cu,Zn)_2CO_3(OH)_2 and au-richalcite (Zn,Cu)_5(CO_3)_2(OH)_6. The former phasewas much easier to be formed than the latter one, while the latter phase was more responsible forthe activity of methanol synthesis than the former one. It is found that the composition andstructure of the precursors altered obviously after the colour transition point. The experimentalresults showed that methanol synthesis is a structure-sensitive catalytic reaction.展开更多
The concept of graphlike manifolds was presented in [1] and the problem of counting the homeomorphic classes of graphlike manifolds has been studied in a series of articles, e.g., [1～8]. In this paper we suggest an a...The concept of graphlike manifolds was presented in [1] and the problem of counting the homeomorphic classes of graphlike manifolds has been studied in a series of articles, e.g., [1～8]. In this paper we suggest an approach based on the graph colouring, Abelian group and the combinatorial enumeration method.展开更多
Evidence for the long-term optical curve variability and colour behaviour of the BL Lac object Mkn 421 is presented. Our results show that the amplitude of the optical variations of Mkn 421 is only about △B=4.7 magni...Evidence for the long-term optical curve variability and colour behaviour of the BL Lac object Mkn 421 is presented. Our results show that the amplitude of the optical variations of Mkn 421 is only about △B=4.7 magnitude in the B-band for its photometric history from 1899 to 2002. The results of optical photometric monitoring of the Mkn 421 from April 2000 to Jan 2002 are provided. During our observation, Mkn 421 shows significant rapid variations and exhibits short time variability of 2.42 hours in the B band. A strong correlation between the B - V colour index and the magnitude in the B band is found. Our charge coupled device （CCD） photometry of Mkn 421 shows that the measured results are in good agreement with the predicted optical variability period of about 23 years.展开更多
This paper reports the fabrication of novel white organic light-emitting device（WOLED） by using a high efficiency blue fluorescent dye N-（4-（（E）-2-（6-（（E）-4-（diphenylamino）styryl）naphthalen-2-yl）vinyl）p...This paper reports the fabrication of novel white organic light-emitting device（WOLED） by using a high efficiency blue fluorescent dye N-（4-（（E）-2-（6-（（E）-4-（diphenylamino）styryl）naphthalen-2-yl）vinyl）phenyl）oN- phenylbenzenamine （N-BDAVBi） and a red phosphoresecent dye bis （1-（phenyl） isoquinoline） iridium （III） acetylanetonate （Ir（piq）2（acac））. The configuration of the device was ITO/PVK：TPD/CBP： N-BDAVBi /CBP/ BALq： Ir（piq）2（acac）/BCP/Alq3/LiF：AL. By adjusting the proportion of the dopants （N-BDAVBi, Ir（piq）2（acac）） in the light-emitting layer, white light with Commission Internationale de l＇Eclairage （CIE） coordinates of （0.35, 0.35） and a maximum luminance of 25350cd/m2 were obtained external quantum and current efficiency of 6.78% and between the two light-emitting layers and using BCP at an applied voltage of 22V. The WOLED exhibits maximum 12cd/A respectively. By placing an undoped spacer CBP layer as hole blocking layer, the colour stabilization slightly changed when the driving voltage increased from 6 to 22 V.展开更多
Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supp...Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supply size,which limit their practical applications.In this paper,a self-driven microplasma decontamination system,induced by a dielectric-dielectric rotary triboelectric nanogenerator(dd-r TENG),was innovatively proposed for the decontamination of CWA simulants.The microplasma was characterized via electrical measurements,optical emission spectra and ozone concentration detection.With an output voltage of-3460 V,the dd-r TENG can successfully excite microplasma in air.Reactive species,such as OH,O(1D),Hαand O3were detected.With input average power of 0.116 W,the decontamination rate of 2-chloroethyl ethyl sulfide reached 100%within 3 min of plasma treatment,while the decontamination rates of malathion and dimethyl methylphosphonate reached(65.92±1.65)%and(60.88±1.92)%after 7 min of plasma treatment,respectively.In addition,the decontamination rates gradually decreased with the increase in the simulant concentrations.Typical products were identified and analyzed.This study demonstrates the broad spectrum and feasibility of the dd-r TENG-microplasma for CWA elimination,which provides significant guidance for their practical applications in the future.展开更多
In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-op...In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-optimized ZnS out-coupling layer.With a 24-nm out-coupling layer,the reflectivity of the cathode is reduced to 8% at 492 nm and the mean reflectivity is 24% in the visible area.By introducing an efficient electron blocking layer tris（1phenylpyrazolato,N,C2 ＇）iridium（III）（Ir（ppz） 3） to confine the exciton recombination area,the current efficiency and the colour stability of the device are effectively improved.A white emission with the Ir（ppz） 3 layer exhibits a maximum current efficiency of 9.8 cd/A at 8 V,and the Commission Internationale de L＇Eclairage（CIE） chromaticity coordinates are almost constant during a large voltage change of 6 V-11 V.There is almost no viewing angular dependence in the spectrum when the viewing angle is no more than 45,with a CIE x,y coordinate variation of only（±0.0025,±0.0008）.Even at a large viewing angle（75）,the CIE x,y coordinate change is as small as（±0.0087,±0.0013）.展开更多
An f-edge cover-colouring of a graph G = (V, E) is an assignment of colours to the edges of G such that every colour appears at each vertex v ∈ V at least f(v) times. The maximum number of colours needed to f-edge co...An f-edge cover-colouring of a graph G = (V, E) is an assignment of colours to the edges of G such that every colour appears at each vertex v ∈ V at least f(v) times. The maximum number of colours needed to f-edge cover colour G is called the f-edge cover chromatic index of G, denoted by Xfc(G). This paper gives that min[d(v)-1/f(v)]≤xfc(G)≤展开更多
The development of surface modification technology for temperature sensitive fibers has been a huge challenge.In this work,a novel technique based on cold plasma treatment was developed for the preparation of anti-bac...The development of surface modification technology for temperature sensitive fibers has been a huge challenge.In this work,a novel technique based on cold plasma treatment was developed for the preparation of anti-bacterial polypropylene(PP)fibers.The results showed that plasma treatment introduced a rough surface and polar groups,which acted as the anchor point and initiators for diallyldimethyl ammonium chloride(DADMAC)graft-polymerization.The fabricated PP membranes presented a high bacterial sterilization rate,as well as excellent adhesion force and washing durability.After ultrasonic treatment for 30 min,the physical coating sample had lost anti-bacterial effect,while the plasma grafted sample still showed a sterilization rate of 91.67%.This work provided a clean and novel DADMAC grafting method and it is also applicable for anti-bacterial material fabrication.展开更多
文摘This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by time-modulated correlated coloured noise sources. The power spectrum and signal-to-noise ratio R of the laser intensity are calculated by the linear approximation. The effects caused by noise self-correlation time τ1, τ2 and cross-correlated time τ3 for stochastic resonance are analysed in two ways： τ1, τ2 and τ3 are taken to be the independent variables and the parameters respectively. The effects of the gain coefficient F and loss coefficient K on the stochastic resonance are also discussed. It is found that besides the presence of the standard form and the broad sense of stochastic resonance, the number of extrema in the curve of R versus K is reduced with the increase of the gain coefficient Г.
基金Project supported by the National Natural Science Foundation of China （Grant No 10472091 and 10332030） and Natural Science Foundation of Shaanxi Province, China （Grant No 2003A03）. The author gratefully acknowledges the support of Youth for NPU Teachers Scientific and Technological Innovation Foundation.
文摘This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the definition of Shannon＇s information entropy, the time dependence of entropy flux and entropy production can be calculated. The present results can be used to explain the extremal behaviour of time dependence of entropy flux and entropy production in view of the dissipative parameter γ of the system, coloured cross-correlation time τ and coloured cross-correlation strength λ.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10472091 and 10332030）, the Natural Science Foundation of Shaanxi Province of China （Grant No 2003A03）.
文摘It is shown how the cross-correlation time and strength of coloured cross-correlated white noises can set an upper bound for the time derivative of entropy in a nonequilibrium system. The value of upper bound can be calculated directly based on the Schwartz inequality principle and the Fokker-Planck equation of the dynamical system driven by coloured cross-correlated white noises. The present calculations can be used to interpret the interplay of the dissipative constant and cross-correlation time and strength of coloured cross-correlated white noises on the upper bound.
基金supported by the Key Project Scientific Research Foundation from the Education Department of Hubei Province of China(Grant No D200725001)
文摘By adding frequency modulated signals to the intensity equation of gain noise model of the single-mode laser driven by two coloured noises which are correlated, this paper uses the linear approximation method to calculate the power spectrum and signal-to-noise ratio （SNR） of the laser intensity. The results show that the SNR appears typical stochastic resonance with the variation of intensity of the pump noise and quantum noise. As the amplitude of a modulated signal has effects on the SNR, it shows suppression, monotone increasing, stochastic resonance, and multiple stochastic resonance with the variation of the frequency of a carrier signal and modulated signal.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10672074)
文摘The phenomenon of stochastic resonance is investigated in an asymmetric bistable system with coloured noises. The approximate Fokker Planck equation is derived based on the Novikov theorem and the Fox approach. By applying the two-state theory, the expression of the signal-to-noise ratio is obtained in the adiabatic limit. The effects of the noise parameters on signal-to-ratio are discussed. It is found that the stochastic resonance phenomena appear in most cases and disappear in some special cases.
基金Project supported partially by National Science Foundation of China (Grant No 10305005)the Fundamental Research Fund for Physics and Mathematic of Lanzhou University of China
文摘In this paper, we studied the effect of Gaussian coloured noise on the formation and instability of spiral waves described by one class of modified FitzHugh Nagumo equation. It was found that Gaussian coloured noise plays a constructive role in the formation, transition and instability of spiral wave. Too weak or too strong noise may act against the formation of spiral waves. At a certain noise level, spiral wave is maintained in a medium, in which spiral wave cannot be observed in the absence of the noise. It is difficult to make a stable spiral wave into unstable state by Gaussian coloured noise, unless the noise level is very high. The parameter regions of Gaussian coloured noise for spiral forming and spiral instability were given and discussed with numerical simulations.
基金supported by the NSF of China under grants No. 61173048 and No. 61300041Specialized Research Fund for the Doctoral Program of Higher Education under grant No. 20130074110015+2 种基金the Fundamental Research Funds for the Central Universities under Grant No.WH1314038the Humanities and Social Science Research Planning Fund of the Education Ministry of China under grant No.15YJCZH201the Research Innovation Program of Shanghai Municipal Education Commission under grant No. 14YZ134
文摘Aspect-oriented modeling can uncover potential design faults, yet most existing work fails to achieve both separation and composition in a natural and succinct way. This study presents an aspect-oriented modeling and analysis approach with hierarchical Coloured Petri Nets(HCPN). HCPN has sub-models and well-defined semantics combining a set of submodels. These two characteristics of HCPN are nicely integrated into aspect oriented modeling. Submodels are used to model aspects while the combination mechanism contributes to aspects weaving. Furthermore, the woven aspect oriented HCPN model can be simulated and analyzed by the CPN Tools. A systematic web application case study is conducted. The results show the system original properties are satisfied after weaving aspects and all design flaws are revealed. As such, the approach can support web application design and analysis in an aspect-oriented fashion concisely and effectively.
文摘Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European market.Later,emeralds from Colombia were shipped via the ocean to the Old World.
基金Project supported by the National Natural Science Foundation of China (Grant No 10275025)
文摘The diffusion in a harmonic oscillator driven by coloured noises ξ（t） and η（t） with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1） The curves of d versus noise intensity D and d versus noises cross-correlation time z3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient A of the two Ornstein-Uhlenbeck （O-U） noises. 2） Changing the value of T3, the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3） Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model.
基金Project supported by the Natural Science Foundation of Yunnan province of China (Grant No 2006A0002M)the Science Foundation of Baoji University of Science and Arts of China (Grant No Zk0697)
文摘This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By directly simulating the Langevin Equation, the following results are obtained. （1） The multiplicative coloured noise dominates, however, the effect of the additive coloured noise is not neglected in the practical gene selection process. The selection rate μ decides that the selection is propitious to gene A haploid or gene B haploid. （2） The additive coloured noise intensity and the correlation time τ2 play opposite roles. It is noted that α and τ2 can not separate the single peak, while can make the peak disappear and ^-2 can make the peak be sharp. （3） The multiplicative coloured noise intensity D and the correlation time τ1 can induce phase transition, at the same time they play opposite roles and the reentrance phenomenon appears. In this case, it is easy to select one type haploid from the group with increasing D and decreasing τ1.
文摘The effect of heat treatment on the surface colour and hygro- scopic properties of pine wood were investigated in this study. Boards of Scots pine wood （Pinus sylvestris L.） were subjected to thermal treatment at 200℃, for 4, 6, and 8 h. The change of equilibrium moisture content and density values of the specimens in order to facilitate the understand- ing of the treated material behavior. The colour parameters L＊ a＊ and b＊, used to depict the total colour change （dE） of wood surface, were shown to change proportionally to the treatment intensity. Moreover, swelling in the tangential and radial directions and absorption of the specimens ap- peared to be enhanced in great extent by the thermal treatment process. The mean value of swelling percentage in the tangential direction de- creased 10.26%, 17.22%, and 19.60% for specimens treated for 4, 6, and 8 h, respectively, referring to the final measurement after 72 h of immer- sion. In radial direction, mean value of swelling percentage decreased 19.56%, 32.75%, and 34.65% for treated for 4, 6 and 8 h, respectively, after 72 h immersion, which attests the decrease in swelling and im- provement in the hygroscopic behavior of Scots pine wood.
文摘The aging process of pure copper precursors and copper-zinc binary precursorswere studied by XRD, TG-DTG and TPR techniques. The catalytic activity and stability of CuO/ZnOwere tested using fixed-bed flow reactor, and the physical properties of the catalysts and Cuspecies were characterized with N_2 adsorption and N_2O passivation method, respectively. For theCu-Zn binary system prepared at the precipitating condition of pH=8.0 and temperature=80℃, theinitial phase was a mixture of copper nitrate hydroxide Cu_2(NO_3)(OH)_3, georgeite and hydrozinciteZn_5(CO_3)_2(OH)_6. By increasing the duration of its aging time, the phase of Cu_2(NO_3)(OH)_2first transited to georgeite, and then interdiffused into Zn_5(CO_3)_2(OH)_6 and resulted in two newphases: rosasite (Cu,Zn)_2CO_3(OH)_2 and au-richalcite (Zn,Cu)_5(CO_3)_2(OH)_6. The former phasewas much easier to be formed than the latter one, while the latter phase was more responsible forthe activity of methanol synthesis than the former one. It is found that the composition andstructure of the precursors altered obviously after the colour transition point. The experimentalresults showed that methanol synthesis is a structure-sensitive catalytic reaction.
文摘The concept of graphlike manifolds was presented in [1] and the problem of counting the homeomorphic classes of graphlike manifolds has been studied in a series of articles, e.g., [1～8]. In this paper we suggest an approach based on the graph colouring, Abelian group and the combinatorial enumeration method.
基金Project supported by an CRCG grant of the University of Hong Kong, Yunnan Provincial Foundation of Science of China （Grant No 2004A0027M） and the National Natural Science Foundation of China（Grant No 10363002）, and the Natural Science Foundation of China Education Department（Grant No 02142）.
文摘Evidence for the long-term optical curve variability and colour behaviour of the BL Lac object Mkn 421 is presented. Our results show that the amplitude of the optical variations of Mkn 421 is only about △B=4.7 magnitude in the B-band for its photometric history from 1899 to 2002. The results of optical photometric monitoring of the Mkn 421 from April 2000 to Jan 2002 are provided. During our observation, Mkn 421 shows significant rapid variations and exhibits short time variability of 2.42 hours in the B band. A strong correlation between the B - V colour index and the magnitude in the B band is found. Our charge coupled device （CCD） photometry of Mkn 421 shows that the measured results are in good agreement with the predicted optical variability period of about 23 years.
文摘This paper reports the fabrication of novel white organic light-emitting device（WOLED） by using a high efficiency blue fluorescent dye N-（4-（（E）-2-（6-（（E）-4-（diphenylamino）styryl）naphthalen-2-yl）vinyl）phenyl）oN- phenylbenzenamine （N-BDAVBi） and a red phosphoresecent dye bis （1-（phenyl） isoquinoline） iridium （III） acetylanetonate （Ir（piq）2（acac））. The configuration of the device was ITO/PVK：TPD/CBP： N-BDAVBi /CBP/ BALq： Ir（piq）2（acac）/BCP/Alq3/LiF：AL. By adjusting the proportion of the dopants （N-BDAVBi, Ir（piq）2（acac）） in the light-emitting layer, white light with Commission Internationale de l＇Eclairage （CIE） coordinates of （0.35, 0.35） and a maximum luminance of 25350cd/m2 were obtained external quantum and current efficiency of 6.78% and between the two light-emitting layers and using BCP at an applied voltage of 22V. The WOLED exhibits maximum 12cd/A respectively. By placing an undoped spacer CBP layer as hole blocking layer, the colour stabilization slightly changed when the driving voltage increased from 6 to 22 V.
基金supported by National Natural Science Foundation of China(No.51877205)Fundamental Research Funds for the Central Universities(No.buct201906)+1 种基金the State Key Laboratory of NBC Protection for Civilian(No.SKLNBC2021-0X)Beijing Nova Program(No.2022015)。
文摘Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supply size,which limit their practical applications.In this paper,a self-driven microplasma decontamination system,induced by a dielectric-dielectric rotary triboelectric nanogenerator(dd-r TENG),was innovatively proposed for the decontamination of CWA simulants.The microplasma was characterized via electrical measurements,optical emission spectra and ozone concentration detection.With an output voltage of-3460 V,the dd-r TENG can successfully excite microplasma in air.Reactive species,such as OH,O(1D),Hαand O3were detected.With input average power of 0.116 W,the decontamination rate of 2-chloroethyl ethyl sulfide reached 100%within 3 min of plasma treatment,while the decontamination rates of malathion and dimethyl methylphosphonate reached(65.92±1.65)%and(60.88±1.92)%after 7 min of plasma treatment,respectively.In addition,the decontamination rates gradually decreased with the increase in the simulant concentrations.Typical products were identified and analyzed.This study demonstrates the broad spectrum and feasibility of the dd-r TENG-microplasma for CWA elimination,which provides significant guidance for their practical applications in the future.
基金Project supported by the Science Fund of the Ministry of Science and Technology,China (Grant No. 2009CB930600)the National Natural Science Foundation of China (Grants Nos. 60907047,61274065,and 60977024)+4 种基金the Key Project of the Chinese Ministryof Education (Grants Nos. 104246 and 707032)the Research Fund for the Doctoral Program of Higher Education Institutions,China (Grant Nos. 20093223120003 and 20093223110003)the Natural Science Foundation of Jiangsu Province and the Higher Education Institutions of Jiangsu Province,China (Grants Nos. BK2009423,SJ209003,10KJB510013,and 11KJD510003)the Fok Ying-Tong Education Foundation,China (Grant No. 111051)the "Qing Lan" Program of Jiangsu Province and the "Pandeng"Project of Nanjing University of Posts and Telecommunications,China (Grant Nos. NY210015,NY211069,and NY210040)
文摘In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-optimized ZnS out-coupling layer.With a 24-nm out-coupling layer,the reflectivity of the cathode is reduced to 8% at 492 nm and the mean reflectivity is 24% in the visible area.By introducing an efficient electron blocking layer tris（1phenylpyrazolato,N,C2 ＇）iridium（III）（Ir（ppz） 3） to confine the exciton recombination area,the current efficiency and the colour stability of the device are effectively improved.A white emission with the Ir（ppz） 3 layer exhibits a maximum current efficiency of 9.8 cd/A at 8 V,and the Commission Internationale de L＇Eclairage（CIE） chromaticity coordinates are almost constant during a large voltage change of 6 V-11 V.There is almost no viewing angular dependence in the spectrum when the viewing angle is no more than 45,with a CIE x,y coordinate variation of only（±0.0025,±0.0008）.Even at a large viewing angle（75）,the CIE x,y coordinate change is as small as（±0.0087,±0.0013）.
文摘An f-edge cover-colouring of a graph G = (V, E) is an assignment of colours to the edges of G such that every colour appears at each vertex v ∈ V at least f(v) times. The maximum number of colours needed to f-edge cover colour G is called the f-edge cover chromatic index of G, denoted by Xfc(G). This paper gives that min[d(v)-1/f(v)]≤xfc(G)≤
基金supported by National Natural Science Foundation of China(Nos.51877205 and 52011530191)Fundamental Research Funds for the Central Universities(No.buctrc201906)Beijing Nova Program(No.2022015)。
文摘The development of surface modification technology for temperature sensitive fibers has been a huge challenge.In this work,a novel technique based on cold plasma treatment was developed for the preparation of anti-bacterial polypropylene(PP)fibers.The results showed that plasma treatment introduced a rough surface and polar groups,which acted as the anchor point and initiators for diallyldimethyl ammonium chloride(DADMAC)graft-polymerization.The fabricated PP membranes presented a high bacterial sterilization rate,as well as excellent adhesion force and washing durability.After ultrasonic treatment for 30 min,the physical coating sample had lost anti-bacterial effect,while the plasma grafted sample still showed a sterilization rate of 91.67%.This work provided a clean and novel DADMAC grafting method and it is also applicable for anti-bacterial material fabrication.
