Based on the concept of the constitutive relation error along with the residuals of both the origin and the dual problems, a goal-oriented error estimation method with extended degrees of freedom is developed. It lead...Based on the concept of the constitutive relation error along with the residuals of both the origin and the dual problems, a goal-oriented error estimation method with extended degrees of freedom is developed. It leads to the high quality locM error bounds in the problem of the direct-solution steady-state dynamic analysis with a frequency-domain finite element, which involves the enrichments with plural variable basis functions. The solution of the steady-state dynamic procedure calculates the harmonic response directly in terms of the physical degrees of freedom in the model, which uses the mass, damping, and stiffness matrices of the system. A three-dimensional finite element example is carried out to illustrate the computational procedures.展开更多
The purpose of this study is to analyze the characteristics of the spatial distribution and change trend of the marketing level of stateowned land supply so as to provide policy recommendations. Method of spatial auto...The purpose of this study is to analyze the characteristics of the spatial distribution and change trend of the marketing level of stateowned land supply so as to provide policy recommendations. Method of spatial autocorrelation analysis is employed. The results indicate that the spatial layout of the land supply marketing level is generally dispersed,but it does assemble in some specific area. The correlation between the marketing level of state-owned land supply and the economic development is not statistically significant. But their relations fluctuate obviously. The overall marketing level of state-owned land supply is increasing and spatially concentrated. The expansion rate of marketing has decreased first and then increased and stabilized now. The high-value cluster center of marketing level of state-owned land supply exists all over the country; however the existence probability of the cluster is bigger in undeveloped areas. It is concluded that spatial autocorrelation analysis is a good method to quantitatively analyze the spatial variation of marketing level of state-owned land supply in China. To grasp the spatial and temporal variations of the marketing level of state-owned land supply is also good to enhance running of the state-owned land market.展开更多
In the present work,transparent and anti-fogging AlPO_(4)-5 films were prepared on glass substrates using a novel developed process.The process entails a simple in-situ sol–gel followed by vapor phase transport.The i...In the present work,transparent and anti-fogging AlPO_(4)-5 films were prepared on glass substrates using a novel developed process.The process entails a simple in-situ sol–gel followed by vapor phase transport.The in-situ sol–gel process was implemented by coating the precursor sols for the synthesis of AlPO4-5 on the glass substrates successively using the spin-coating method.The films and powders scribed from the films were characterized by X-Ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),atomic force microscope(AFM),X-ray photoelectron spectroscopy and transmission electron microscope(TEM).The unique films were composed of oblique oriented nanoflake AlPO_(4)-5 crystals with the thickness of about 20 nm.The formation of nano-flake crystals can be ascribed to the high concentration of the precursors,resulting in the formation of a supersaturation system.The obtained films showed high antifogging performance due to the superhydrophilicity with a water contact angle of lower than 1.0°.The silicone oil contact angle was also low about 8.2°.In addition,heteroatom-substituted AlPO_(4)-5 films showing different colors can be obtained easily by simply adding transition metal ions in the phosphate acid solution during the preparation that can extend the application of the method for different coating demand.展开更多
This article generalizes our previous results for a quantum system of two nodes to a quantum system ofm(m ≥ 2) nodes. It shows that there is a one to one correspondence between 2m GHZ states for a quantum system ofm...This article generalizes our previous results for a quantum system of two nodes to a quantum system ofm(m ≥ 2) nodes. It shows that there is a one to one correspondence between 2m GHZ states for a quantum system ofm(m ≥ 2) nodes and 2m oriented links of the linkage N1 in knot theory, where N = 4 C2m = 2m(m - 1) is the numberof crossings of the link with m components, the subscript 1 denotes the order of the unoriented m components link withN crossings, i.e. the first type, actually the simplest type.展开更多
Based on the state governance background of peasant household oriented land circulation,I analyzed characteristics of peasant household oriented land circulation.The characteristics mainly include uncertain definition...Based on the state governance background of peasant household oriented land circulation,I analyzed characteristics of peasant household oriented land circulation.The characteristics mainly include uncertain definition of rural land circulation,significant off-media feature of land circulation,long-term land circulation contract,farmers' preference of peasant household oriented land circulation,and progressive path of land circulation.The essential feature is the progressive mode of land circulation.Under the existing property right,it realizes the perfect combination of modern production factors and traditional agricultural,and the combination of traditional family safeguarding function and modern social mutual growth spirit.Thus,it shows relative independence and manifests the idea of common prosperity.The opportunity cost of peasant household oriented land circulation is minimal,institutional cost will increase circulation risk,and what's more,the cost for state governance of peasant household oriented land circulation is minimal.It comes to conclusion that building proper and harmonious land circulation mechanism is responsibility of central government and favorable for healthy development of peasant household oriented land circulation.展开更多
Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize acti...Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize active damping for LCL filters and improve dynamic performance of current regulators,a state space current PI controller is proposed whose parameters can be tuned based on the polynomial equations approach.An extended state observer is integrated with the regulation scheme,where additional sensors are not necessary in contrast with conventional active damping strategies.Synchronous reference frame PLL(SRF⁃PLL)equipped with filter technology is proposed for grid voltage disturbance suppression.This method is then applied to establish a double⁃closed⁃loop power regulator that demonstrates improved performance compared with other controllers.The simulation results are displayed to illustrate the efficiency of the regulation methods.展开更多
A new approach to synthesize liquid crystalline polymer with narrow polydispersity index(PDI) was developed.Photopolymerization of 4-cyanophenyl-4'-(6-acryloyloxyhexyloxy)benzoate(RM23) in nematic liquid crysta...A new approach to synthesize liquid crystalline polymer with narrow polydispersity index(PDI) was developed.Photopolymerization of 4-cyanophenyl-4'-(6-acryloyloxyhexyloxy)benzoate(RM23) in nematic liquid crystals with macroscopic orientation was studied.The effects of the monomer concentration on the molecular weight and PDI of the resulting polymers were studied through gel permeation chromatography(GPC) and polarized optical microscopy.The low PDI of 1.19 and 1.22 was obtained in the reverse and normal modes,respectively.The PDI and molecular weight increased with monomer concentration.展开更多
Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of ...Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland.展开更多
Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable...Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable normal stress condition, and comparison was made between our results and that of fixed normal stress cases revealed in previous studies. For systems associated with the slip law, the critical mag- nitude of rate steps for triggering unstable slips are found to have a similar pattern to the fixed normal stress case, and the critical velocity steps scale with a/(b - a) when k = kcr for both cases. The rate-step boundaries for the variable normal stress cases are revealed to be lower than the fixed normal stress case by 7 %-16 % for a relatively large ct = 0.56 with (b - a)/a ranging from 0.25 to 1, indicating easier triggering under the variable normal stress condition with rate steps. The difference between fixed and variable normal stress cases decreases when the α value is smaller. In the same slip- law-type systems, critical displacements to trigger instability are revealed to be little affected by the variable normal stress condition. When k 〉 kcr(V,), a spring-slider system with the slowness law is much more stable than with the slip law,suggesting that the slowness law fits experimental data better when a single state variable is adopted. In stick-slip motions, the variable normal stress case has larger stress drops than the constant normal stress case. The variable normal stress has little effect on the range of slip velocity in systems associated with the slowness law, whereas systems associated with the slip law have a slowest slip velocity immensely smaller than the fixed normal stress case, by ~ 10 orders of magnitude.展开更多
The synthesis process for La 1- x Sr x Mn 1- y Co y O 3- δ ( x = 0.2, 0.3; y = 0.2, 0.8, designated as LSMC below) perovskite oxides prepared by solid state reaction was investigated using DSC/TG, XRD, EPMA and parti...The synthesis process for La 1- x Sr x Mn 1- y Co y O 3- δ ( x = 0.2, 0.3; y = 0.2, 0.8, designated as LSMC below) perovskite oxides prepared by solid state reaction was investigated using DSC/TG, XRD, EPMA and particle size analysis methods. It was found that LSMCs were all of single phase and the synthesis process might be divided into three stages: the decomposition of reactants, the formation of LaMn(Co)O 3 based oxides, and the formation of LSMC solid solution. Typical average and the peak value of particle size, and the specific surface area are 14.65?μm, 16.4?μm and 1.38?m 2/mL, respectively, for mixed reactants and are 23.81?μm, 32.11?μm and 0.5?m 2/mL, respectively, for powder synthesized at 1?200?℃ for 8?h in air.展开更多
In this paper we develop several new refinement relations of Z for multiple viewpoints oriented requirements method (MVORM). The original motivation is that we found the standard Z refinement relation is not adequate ...In this paper we develop several new refinement relations of Z for multiple viewpoints oriented requirements method (MVORM). The original motivation is that we found the standard Z refinement relation is not adequate or correct when considering specifications that have temporal relationships of operations. The concept of temporal state variables is introduced into Z. Then new implementation relations are defined and new refinement relations are deduced, mainly for temporal state variables to process temporal relationships of operations. We use state transition systems to abstract the temporal state transitions. A simple example is used to show the procedures of MVORM. Finally some directions of further work are forwarded.展开更多
ITIC is the milestone of non-fullerene small molecule acceptors used in organic solar cells. We study the electronic states and molecular orientation of ITIC film using photoelectron spectroscopy and x-ray absorption ...ITIC is the milestone of non-fullerene small molecule acceptors used in organic solar cells. We study the electronic states and molecular orientation of ITIC film using photoelectron spectroscopy and x-ray absorption spectroscopy. The negative integer charge transfer energy level is determined to be 4.00 ± 0.05 eV below the vacuum level, and the ionization potential is 5,75 ±0.10 eV. The molecules predominantly have the face-on orientation on inert substrates as long as the surfaces of the substrates are not too rough. These results provide the physical understanding of the high performance of ITIC-based solar ceils, which also afford implications to design more advanced photovoltaic small molecules.展开更多
A mathematical model has been developed to handle the reactions in Poly(ethylene terephthalate) (PET) undergoing polycondensation reactions in the solid state. The effect of temperature on chain mobility was considere...A mathematical model has been developed to handle the reactions in Poly(ethylene terephthalate) (PET) undergoing polycondensation reactions in the solid state. The effect of temperature on chain mobility was considered to estimate the rate constants of chemical reactions. The polymer crystalline fraction is modeled as containing only repeat units, thus concentrating end groups and conden-sates in the amorphous fraction. This model is compared with PET reaction data with good results.展开更多
The equation of state of nuclear matter is studied in the 1-loop approximation of chiral linear σ-ω model.By introducing the density-dependent coupling constants, the problem of tachyon pole in the chiral σ-ω mode...The equation of state of nuclear matter is studied in the 1-loop approximation of chiral linear σ-ω model.By introducing the density-dependent coupling constants, the problem of tachyon pole in the chiral σ-ω model is resolved.The 1-loop contributions ofσ and π mesons to the nucleon's binding energy are included, while the empirical properties of nuclear matter such as saturation density, binding energy, and incompressibility are well reproduced.展开更多
Given the demand for constantly scaling micro- electronic devices to ever smaller dimensions, a SiO2 gate dielectric was substituted with a higher dielectric-constant material, Hf(Zr)O2, in order to minimize current...Given the demand for constantly scaling micro- electronic devices to ever smaller dimensions, a SiO2 gate dielectric was substituted with a higher dielectric-constant material, Hf(Zr)O2, in order to minimize current leakage through dielectric thin film. However, upon interfacing with high dielectric constant (high-κ) dielectrics, the electron mobility in the conventional Si channel degrades due to Coulomb scattering, surface-roughness scattering, remotephonon scattering, and dielectric-charge trapping.Ⅲ-Ⅴ and Ge are two promising candidates with superior mobility over Si. Nevertheless, Hf(Zr)O2/Ⅲ-Ⅴ(Ge) has much more complicated interface bonding than Si-based interfaces. Successful fabrication of a high-quality device critically depends on understanding and engineering the bonding configurations at Hf(Zr)O2/Ⅲ-Ⅴ(Ge) interfaces for the optimal design of device interfaces. Thus, an accurate atomic insight into the interface bonding and mechanism of interface gap states formation becomes essential. Here, we utilize first- principle calculations to investigate the interface between HfO2 and GaAs. Our study shows that As--As dimer bonding, Ga partial oxidation (between 3+ and 1+) and Ga- dangling bonds constitute the major contributions to gap states. These findings provide insightful guidance for optimum interface passivation.展开更多
EPR raised fundamental problems of non-locality (NL) in the case of entangled states (ES) 82 years ago. These problems were not solved until now. EPR and their followers used and would continue to use calculation meth...EPR raised fundamental problems of non-locality (NL) in the case of entangled states (ES) 82 years ago. These problems were not solved until now. EPR and their followers used and would continue to use calculation methods that were available at that time. However, we can easily explain this observable NL as a trivial result of conservation laws (CL) within modern quantum mechanics (MQM). But application of CL requires materialistic descriptions of reality in a micro world in contrast to so-called quantum measurement theory (QMT), which was created mainly in the times of EPR and is widely accepted until now. We have to use a materialistic description, just as many physicists who actually work with high precision do by default. In this article, practical examples are given for real, precise measurements of wave functions of molecules and crystals, which, of course, were not known to EPR and were not noticed by their followers. We should acknowledge that QMT is merely an unneeded complication of simple relations of MQM. NL is the seeming result of these complications.展开更多
Facing economic crisis in the world 2009, international market demands suffered a serious recession, also China's foreign trade has encountered unprecedented difficulties. In front of this, Chinese Government take...Facing economic crisis in the world 2009, international market demands suffered a serious recession, also China's foreign trade has encountered unprecedented difficulties. In front of this, Chinese Government takes series of adjustment timely to get over this rough time. So how is China's foreign trade in 2009, and where it will go in 2010, let's have a look at this…展开更多
IEC-60870-5-104规约作为采用标准传输协议子集的IEC60870-5-101的网络访问,由于涉及到网络编程以及颁布时间较晚,在电力系统中还处于推广阶段。目前对104规约的探讨不论是应用还是研究都比较深入,并且取得了一定的成绩,但在软件设计方...IEC-60870-5-104规约作为采用标准传输协议子集的IEC60870-5-101的网络访问,由于涉及到网络编程以及颁布时间较晚,在电力系统中还处于推广阶段。目前对104规约的探讨不论是应用还是研究都比较深入,并且取得了一定的成绩,但在软件设计方面,还没有形成较统一的开发模式,迫切需要一个好的设计方法和工具帮助开发者设计开发通信软件。基于有限状态机理论提出一种设计方法用于104规约的实现。在这种设计方法中,结合通信协议的分层思想进行软件的总体设计,同时应用有限状态机(Finite State Machine,FSM)理论对104规约建模,抽象出有限状态机模型,并提出一种面向对象的FSM实现框架及其配置工具,利用配置工具自动实现FSM。展开更多
基金Project supported by the National Natural Science Foundation of China (No. 10876100)
文摘Based on the concept of the constitutive relation error along with the residuals of both the origin and the dual problems, a goal-oriented error estimation method with extended degrees of freedom is developed. It leads to the high quality locM error bounds in the problem of the direct-solution steady-state dynamic analysis with a frequency-domain finite element, which involves the enrichments with plural variable basis functions. The solution of the steady-state dynamic procedure calculates the harmonic response directly in terms of the physical degrees of freedom in the model, which uses the mass, damping, and stiffness matrices of the system. A three-dimensional finite element example is carried out to illustrate the computational procedures.
基金Supported by Chongqing Key Humanities and Social Sciences Base--Research Center of Rural Economics and Management of Southwest University
文摘The purpose of this study is to analyze the characteristics of the spatial distribution and change trend of the marketing level of stateowned land supply so as to provide policy recommendations. Method of spatial autocorrelation analysis is employed. The results indicate that the spatial layout of the land supply marketing level is generally dispersed,but it does assemble in some specific area. The correlation between the marketing level of state-owned land supply and the economic development is not statistically significant. But their relations fluctuate obviously. The overall marketing level of state-owned land supply is increasing and spatially concentrated. The expansion rate of marketing has decreased first and then increased and stabilized now. The high-value cluster center of marketing level of state-owned land supply exists all over the country; however the existence probability of the cluster is bigger in undeveloped areas. It is concluded that spatial autocorrelation analysis is a good method to quantitatively analyze the spatial variation of marketing level of state-owned land supply in China. To grasp the spatial and temporal variations of the marketing level of state-owned land supply is also good to enhance running of the state-owned land market.
基金financial support from the Key University Science Research Project of Jiangsu Province(16KJA430007)Opening Topic of Key Laboratory of Attapulgite Resources Utilization in Jiangsu Province(HPK201804)Opening Topic of National Local Joint Engineering Research Center for Deep Utilization of Mineral and Salt Resources(SF201804)。
文摘In the present work,transparent and anti-fogging AlPO_(4)-5 films were prepared on glass substrates using a novel developed process.The process entails a simple in-situ sol–gel followed by vapor phase transport.The in-situ sol–gel process was implemented by coating the precursor sols for the synthesis of AlPO4-5 on the glass substrates successively using the spin-coating method.The films and powders scribed from the films were characterized by X-Ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),atomic force microscope(AFM),X-ray photoelectron spectroscopy and transmission electron microscope(TEM).The unique films were composed of oblique oriented nanoflake AlPO_(4)-5 crystals with the thickness of about 20 nm.The formation of nano-flake crystals can be ascribed to the high concentration of the precursors,resulting in the formation of a supersaturation system.The obtained films showed high antifogging performance due to the superhydrophilicity with a water contact angle of lower than 1.0°.The silicone oil contact angle was also low about 8.2°.In addition,heteroatom-substituted AlPO_(4)-5 films showing different colors can be obtained easily by simply adding transition metal ions in the phosphate acid solution during the preparation that can extend the application of the method for different coating demand.
文摘This article generalizes our previous results for a quantum system of two nodes to a quantum system ofm(m ≥ 2) nodes. It shows that there is a one to one correspondence between 2m GHZ states for a quantum system ofm(m ≥ 2) nodes and 2m oriented links of the linkage N1 in knot theory, where N = 4 C2m = 2m(m - 1) is the numberof crossings of the link with m components, the subscript 1 denotes the order of the unoriented m components link withN crossings, i.e. the first type, actually the simplest type.
基金Supported by Henan Province Philosophy and Social Science Planning Project (2010FJJ045)Decision-making Project of Henan Provincial Government (2011B559)
文摘Based on the state governance background of peasant household oriented land circulation,I analyzed characteristics of peasant household oriented land circulation.The characteristics mainly include uncertain definition of rural land circulation,significant off-media feature of land circulation,long-term land circulation contract,farmers' preference of peasant household oriented land circulation,and progressive path of land circulation.The essential feature is the progressive mode of land circulation.Under the existing property right,it realizes the perfect combination of modern production factors and traditional agricultural,and the combination of traditional family safeguarding function and modern social mutual growth spirit.Thus,it shows relative independence and manifests the idea of common prosperity.The opportunity cost of peasant household oriented land circulation is minimal,institutional cost will increase circulation risk,and what's more,the cost for state governance of peasant household oriented land circulation is minimal.It comes to conclusion that building proper and harmonious land circulation mechanism is responsibility of central government and favorable for healthy development of peasant household oriented land circulation.
文摘Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize active damping for LCL filters and improve dynamic performance of current regulators,a state space current PI controller is proposed whose parameters can be tuned based on the polynomial equations approach.An extended state observer is integrated with the regulation scheme,where additional sensors are not necessary in contrast with conventional active damping strategies.Synchronous reference frame PLL(SRF⁃PLL)equipped with filter technology is proposed for grid voltage disturbance suppression.This method is then applied to establish a double⁃closed⁃loop power regulator that demonstrates improved performance compared with other controllers.The simulation results are displayed to illustrate the efficiency of the regulation methods.
基金The authors are grateful to NSF of China(No.50703013)Independent Innovative Position of Hubei Province for financial support of this work
文摘A new approach to synthesize liquid crystalline polymer with narrow polydispersity index(PDI) was developed.Photopolymerization of 4-cyanophenyl-4'-(6-acryloyloxyhexyloxy)benzoate(RM23) in nematic liquid crystals with macroscopic orientation was studied.The effects of the monomer concentration on the molecular weight and PDI of the resulting polymers were studied through gel permeation chromatography(GPC) and polarized optical microscopy.The low PDI of 1.19 and 1.22 was obtained in the reverse and normal modes,respectively.The PDI and molecular weight increased with monomer concentration.
文摘Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland.
基金supported by the National Natural Science Foundation of China under Grant Nos.40574080 and 41274186
文摘Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable normal stress condition, and comparison was made between our results and that of fixed normal stress cases revealed in previous studies. For systems associated with the slip law, the critical mag- nitude of rate steps for triggering unstable slips are found to have a similar pattern to the fixed normal stress case, and the critical velocity steps scale with a/(b - a) when k = kcr for both cases. The rate-step boundaries for the variable normal stress cases are revealed to be lower than the fixed normal stress case by 7 %-16 % for a relatively large ct = 0.56 with (b - a)/a ranging from 0.25 to 1, indicating easier triggering under the variable normal stress condition with rate steps. The difference between fixed and variable normal stress cases decreases when the α value is smaller. In the same slip- law-type systems, critical displacements to trigger instability are revealed to be little affected by the variable normal stress condition. When k 〉 kcr(V,), a spring-slider system with the slowness law is much more stable than with the slip law,suggesting that the slowness law fits experimental data better when a single state variable is adopted. In stick-slip motions, the variable normal stress case has larger stress drops than the constant normal stress case. The variable normal stress has little effect on the range of slip velocity in systems associated with the slowness law, whereas systems associated with the slip law have a slowest slip velocity immensely smaller than the fixed normal stress case, by ~ 10 orders of magnitude.
文摘The synthesis process for La 1- x Sr x Mn 1- y Co y O 3- δ ( x = 0.2, 0.3; y = 0.2, 0.8, designated as LSMC below) perovskite oxides prepared by solid state reaction was investigated using DSC/TG, XRD, EPMA and particle size analysis methods. It was found that LSMCs were all of single phase and the synthesis process might be divided into three stages: the decomposition of reactants, the formation of LaMn(Co)O 3 based oxides, and the formation of LSMC solid solution. Typical average and the peak value of particle size, and the specific surface area are 14.65?μm, 16.4?μm and 1.38?m 2/mL, respectively, for mixed reactants and are 23.81?μm, 32.11?μm and 0.5?m 2/mL, respectively, for powder synthesized at 1?200?℃ for 8?h in air.
基金Supported by Natural Science Foundation of Hubei Province (98J0 75 ) Ziqiang Technical Innovation Foundation ofWuhan Universi
文摘In this paper we develop several new refinement relations of Z for multiple viewpoints oriented requirements method (MVORM). The original motivation is that we found the standard Z refinement relation is not adequate or correct when considering specifications that have temporal relationships of operations. The concept of temporal state variables is introduced into Z. Then new implementation relations are defined and new refinement relations are deduced, mainly for temporal state variables to process temporal relationships of operations. We use state transition systems to abstract the temporal state transitions. A simple example is used to show the procedures of MVORM. Finally some directions of further work are forwarded.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11374258 and 11079028)
文摘ITIC is the milestone of non-fullerene small molecule acceptors used in organic solar cells. We study the electronic states and molecular orientation of ITIC film using photoelectron spectroscopy and x-ray absorption spectroscopy. The negative integer charge transfer energy level is determined to be 4.00 ± 0.05 eV below the vacuum level, and the ionization potential is 5,75 ±0.10 eV. The molecules predominantly have the face-on orientation on inert substrates as long as the surfaces of the substrates are not too rough. These results provide the physical understanding of the high performance of ITIC-based solar ceils, which also afford implications to design more advanced photovoltaic small molecules.
文摘A mathematical model has been developed to handle the reactions in Poly(ethylene terephthalate) (PET) undergoing polycondensation reactions in the solid state. The effect of temperature on chain mobility was considered to estimate the rate constants of chemical reactions. The polymer crystalline fraction is modeled as containing only repeat units, thus concentrating end groups and conden-sates in the amorphous fraction. This model is compared with PET reaction data with good results.
文摘The equation of state of nuclear matter is studied in the 1-loop approximation of chiral linear σ-ω model.By introducing the density-dependent coupling constants, the problem of tachyon pole in the chiral σ-ω model is resolved.The 1-loop contributions ofσ and π mesons to the nucleon's binding energy are included, while the empirical properties of nuclear matter such as saturation density, binding energy, and incompressibility are well reproduced.
基金supported by the National Natural Science Foundation of China (11304161, 11104148, and 51171082)the Tianjin Natural Science Foundation (13JCYBJC41100 and 14JCZDJC37700)+3 种基金the National Basic Research Program of China (973 Program) (2014CB931703)Specialized Research Fund for the Doctoral Program of Higher Education (20110031110034)the Fundamental Research Funds for the Central Universitiessupported by the Global Frontier Center for Multiscale Energy Systems at Seoul National University in Korea
文摘Given the demand for constantly scaling micro- electronic devices to ever smaller dimensions, a SiO2 gate dielectric was substituted with a higher dielectric-constant material, Hf(Zr)O2, in order to minimize current leakage through dielectric thin film. However, upon interfacing with high dielectric constant (high-κ) dielectrics, the electron mobility in the conventional Si channel degrades due to Coulomb scattering, surface-roughness scattering, remotephonon scattering, and dielectric-charge trapping.Ⅲ-Ⅴ and Ge are two promising candidates with superior mobility over Si. Nevertheless, Hf(Zr)O2/Ⅲ-Ⅴ(Ge) has much more complicated interface bonding than Si-based interfaces. Successful fabrication of a high-quality device critically depends on understanding and engineering the bonding configurations at Hf(Zr)O2/Ⅲ-Ⅴ(Ge) interfaces for the optimal design of device interfaces. Thus, an accurate atomic insight into the interface bonding and mechanism of interface gap states formation becomes essential. Here, we utilize first- principle calculations to investigate the interface between HfO2 and GaAs. Our study shows that As--As dimer bonding, Ga partial oxidation (between 3+ and 1+) and Ga- dangling bonds constitute the major contributions to gap states. These findings provide insightful guidance for optimum interface passivation.
文摘EPR raised fundamental problems of non-locality (NL) in the case of entangled states (ES) 82 years ago. These problems were not solved until now. EPR and their followers used and would continue to use calculation methods that were available at that time. However, we can easily explain this observable NL as a trivial result of conservation laws (CL) within modern quantum mechanics (MQM). But application of CL requires materialistic descriptions of reality in a micro world in contrast to so-called quantum measurement theory (QMT), which was created mainly in the times of EPR and is widely accepted until now. We have to use a materialistic description, just as many physicists who actually work with high precision do by default. In this article, practical examples are given for real, precise measurements of wave functions of molecules and crystals, which, of course, were not known to EPR and were not noticed by their followers. We should acknowledge that QMT is merely an unneeded complication of simple relations of MQM. NL is the seeming result of these complications.
文摘Facing economic crisis in the world 2009, international market demands suffered a serious recession, also China's foreign trade has encountered unprecedented difficulties. In front of this, Chinese Government takes series of adjustment timely to get over this rough time. So how is China's foreign trade in 2009, and where it will go in 2010, let's have a look at this…
文摘IEC-60870-5-104规约作为采用标准传输协议子集的IEC60870-5-101的网络访问,由于涉及到网络编程以及颁布时间较晚,在电力系统中还处于推广阶段。目前对104规约的探讨不论是应用还是研究都比较深入,并且取得了一定的成绩,但在软件设计方面,还没有形成较统一的开发模式,迫切需要一个好的设计方法和工具帮助开发者设计开发通信软件。基于有限状态机理论提出一种设计方法用于104规约的实现。在这种设计方法中,结合通信协议的分层思想进行软件的总体设计,同时应用有限状态机(Finite State Machine,FSM)理论对104规约建模,抽象出有限状态机模型,并提出一种面向对象的FSM实现框架及其配置工具,利用配置工具自动实现FSM。