Many systems of fuzzy linear equations do not have solutions when the solution concept is based on α cuts and interval arithmetic. In this paper,we establish the relations between the systems of fuzzy linear equation...Many systems of fuzzy linear equations do not have solutions when the solution concept is based on α cuts and interval arithmetic. In this paper,we establish the relations between the systems of fuzzy linear equations and the possibilistic linear programming problems and present an alternative method of solving the systems of fuzzy linear equations.展开更多
The cohesion weakening and friction strengthening(CWFS)model for rock reveals the strength components mobilization process during progressive brittle failure process of rock,which is very helpful in understanding mech...The cohesion weakening and friction strengthening(CWFS)model for rock reveals the strength components mobilization process during progressive brittle failure process of rock,which is very helpful in understanding mechanical properties of rock.However,the used incremental cyclic loading−unloading compression test for the determination of strength components is very complicated,which limits the application of CWFS model.In this paper,incremental cyclic loading−unloading compression test was firstly carried out to study the evolution of deformation and the strength properties of Beishan granite after various temperatures treated under different confining pressures.We found the axial and lateral unloading modulus are closely related to the applied stress and damage state of rock.Based on these findings,we can accurately determine the plastic strain during the entire failure process using conventional tri-axial compression test data.Furthermore,a strength component(cohesive and frictional strength)determination method was developed using conventional triaxial compression test.Using this method,we analyzed the variation of strength mobilization and deformation properties of Beishan granite after various temperatures treated.At last,a non-simultaneous strength mobilization model for thermally treated granite was obtained and verified by numerical simulation,which demonstrated the effectiveness of the proposed strength determination method.展开更多
One of the many issues in utilizing ERP systems in organizations are, in fact, the implementation stage. This study by investigating the common and available methods of implementation, as well as their inefficiencies ...One of the many issues in utilizing ERP systems in organizations are, in fact, the implementation stage. This study by investigating the common and available methods of implementation, as well as their inefficiencies will provide a new more efficient method. This new method, in fact, will first assess the required time of implementation in each of the units of the organization, and then will take advantage of a spherical model with central core instead of a linear model. These units, with regard to the required time of implementation, will surround this core as in the form of some layers. The circuits are ordered in a way that the further we move from the core towards the external layers, the shorter the required time of implementation will become. This way, the priority of implementing ERP will be assigned with a direction from external layers to internal layers. Eventually, all the experiences of the previous stages will be transferred to the central core, which has the most complexity. Through this method, it is expected that we may prevent the fully parallel issue, which was a dominant and apparent issue in previous models, so that the required time of implementation would decrease.展开更多
Using the finite element method and Cole-Cole model for dual-frequency IP method to research numerical simulation, the authors introduced the fundamental principle of the dual-frequency IP method and the boundary valu...Using the finite element method and Cole-Cole model for dual-frequency IP method to research numerical simulation, the authors introduced the fundamental principle of the dual-frequency IP method and the boundary value problem and variational equations, then replaced the complex resistivity of the model with the Cole-Cole model's parameters under ignoring the EM effect. Through solving the last linear equations, electric potentials of all the model's points were obtained. With changing model's parameters, the authors got different curves of the Fs and phases. According to the results of the simulation, the algorithm is proved to be correct and adaptable.展开更多
The accuracy of nucleation parameter is a critical factor in the simulation of microstructural evolution during dynamic recrystallization(DRX).Based on the flow stress curve under hot deformation conditions,a new appr...The accuracy of nucleation parameter is a critical factor in the simulation of microstructural evolution during dynamic recrystallization(DRX).Based on the flow stress curve under hot deformation conditions,a new approach is proposed to identify the nucleation parameter during DRX.In this approach,a cellular automaton(CA) model is applied to quantitatively simulate the microstructural evolution and flow stress during hot deformation;and adaptive response surface method(ARSM) is applied as optimization model to provide input parameters to CA model and evaluate the outputs of the latter.By taking an oxygen-free high-conductivity(OFHC) copper as an example,the good agreement between the simulation results and the experimental observations demonstrates the availability of the proposed method.展开更多
Many ontologies are provided to representing semantic sensors data.However,heterogeneity exists in different sensors which makes some service operators of Internet of Thing(IoT) difficult(such as such as semantic infe...Many ontologies are provided to representing semantic sensors data.However,heterogeneity exists in different sensors which makes some service operators of Internet of Thing(IoT) difficult(such as such as semantic inferring,non-linear inverted index establishing,service composing) .There is a great deal of research about sensor ontology alignment dealing with the heterogeneity between the different sensor ontologies,but fewer solutions focus on exploiting syntaxes in a sensor ontology and the pattern of accessing alignments.Our solution infers alignments by extending structural subsumption algorithms to analyze syntaxes in a sensor ontology,and then combines the alignments with the SKOS model to construct the integration sensor ontology,which can be accessed via the IoT.The experiments show that the integration senor ontology in the SKOS model can be utilized via the IoT service,and the accuracy of our prototype,in average,is higher than others over the four real ontologies.展开更多
Strong mechanical vibration and acoustical signals of grinding process contain useful information related to load parameters in ball mills. It is a challenge to extract latent features and construct soft sensor model ...Strong mechanical vibration and acoustical signals of grinding process contain useful information related to load parameters in ball mills. It is a challenge to extract latent features and construct soft sensor model with high dimensional frequency spectra of these signals. This paper aims to develop a selective ensemble modeling approach based on nonlinear latent frequency spectral feature extraction for accurate measurement of material to ball volume ratio. Latent features are first extracted from different vibrations and acoustic spectral segments by kernel partial least squares. Algorithms of bootstrap and least squares support vector machines are employed to produce candidate sub-models using these latent features as inputs. Ensemble sub-models are selected based on genetic algorithm optimization toolbox. Partial least squares regression is used to combine these sub-models to eliminate collinearity among their prediction outputs. Results indicate that the proposed modeling approach has better prediction performance than previous ones.展开更多
Numerical simulation of antennae is a topic in computational electromagnetism,which is concerned withthe numerical study of Maxwell equations.By discrete exterior calculus and the lattice gauge theory with coefficient...Numerical simulation of antennae is a topic in computational electromagnetism,which is concerned withthe numerical study of Maxwell equations.By discrete exterior calculus and the lattice gauge theory with coefficient R,we obtain the Bianchi identity on prism lattice.By defining an inner product of discrete differential forms,we derivethe source equation and continuity equation.Those equations compose the discrete Maxwell equations in vacuum caseon discrete manifold,which are implemented on Java development platform to simulate the Gaussian pulse radiation onantennaes.展开更多
In this paper, a new control method for synchronous motor with excitation and damper windings is presented. It is based on one type of nonlinear control; feedback linearization control. To make a realization in the se...In this paper, a new control method for synchronous motor with excitation and damper windings is presented. It is based on one type of nonlinear control; feedback linearization control. To make a realization in the sense of electric drive, symmetricM space vector PWM (pulse width modulation) is applied. Estimation of damper winding currents via Lyapunov function for the whole estimated system is done. The aim of control is to make tracking system for rotor speed and square of stator flux. Simulation of motor starting to predefined operating points is done, and also maintaining these points during step change of load torque is obtained. Simulations give good results.展开更多
Dried anaerobic granular sludge (DAGS) for removing phenol (organic) and lead (inorganic) pollutants from synthetic wastewater was examined in a fixed bed system. A general rate multi-component model has been bu...Dried anaerobic granular sludge (DAGS) for removing phenol (organic) and lead (inorganic) pollutants from synthetic wastewater was examined in a fixed bed system. A general rate multi-component model has been built to predict the fixed bed breakthrough curves for single and dual-component system. This model considers both external and internal mass transfer resistances as well as axial dispersion with non-liner multi-component isotherm. The equilibrium isotherm model parameters such as isotherm model constants (qm and b), pore diffusion coefficients (Dp) were obtained from batch experiments, while the external mass transfer coefficients and axial dispersion (kf, Dz) were calculated from empirical correlations. The results show that the general rate multi-component model was found suitable for describing the biosorption process of the dynamic behavior of the DAGS adsorber column and that DAGS can be used efficiently to remove organic and inorganic pollutants.展开更多
The actinomycete populations and functions in cadmium (Cd) contaminated soil were investigated by the cultivation- independent molecular methods. The genomic DNA was extracted and purified from soil adulterated with...The actinomycete populations and functions in cadmium (Cd) contaminated soil were investigated by the cultivation- independent molecular methods. The genomic DNA was extracted and purified from soil adulterated with various con- centrations of Cd in the laboratory. The partial 16S rDNA genes were amplified by polymerase chain reaction (PCR) using specific primers bound to evolutionarily conserved regions within these actinomycete genes. The diversity in PCR- amplified products, as measured by denaturing gradient gel electrophoresis (EGGE), was used as a genetic fingerprint of the population. Principle component analysis and Shannon-Weaver diversity index (H) analyses were used to analyze the DGGE results. Results showed that the two principal components accounted for only a low level of the total variance. The value H in contaminated soil was lower than that in the control at later stages of cultivation, whereas at earlier stages it was higher. Among the six sampling time points, the first, fifth and sixth weeks had the highest values of H. Significantly negative correlations between bioavallable Cd concentration and H values existed in the samples from weeks 2 (R = 0.929, P 〈 0.05) and 4 (R = 0.909, P 〈 0.05). These results may shed light on the effect of Cd on the soil environment and the chemical behavior and toxicity of Cd to actinomycetes.展开更多
A model that rapidly predicts the density components of raw coal is described.It is based on a threegrade fast float/sink test.The recent comprehensive monthly floating and sinking data are used for comparison.The pre...A model that rapidly predicts the density components of raw coal is described.It is based on a threegrade fast float/sink test.The recent comprehensive monthly floating and sinking data are used for comparison.The predicted data are used to draw washability curves and to provide a rapid evaluation of the effect from heavy medium induced separation.Thirty-one production shifts worth of fast float/sink data and the corresponding quick ash data are used to verify the model.The results show a small error with an arithmetic average of 0.53 and an absolute average error of 1.50.This indicates that this model has high precision.The theoretical yield from the washability curves is 76.47% for the monthly comprehensive data and 81.31% using the model data.This is for a desired cleaned coal ash of 9%.The relative error between these two is 6.33%,which is small and indicates that the predicted data can be used to rapidly evaluate the separation effect of gravity separation equipment.展开更多
An investigation has been made on the models and characteristics of triple-frequency carrier-phase linear combinations for the Bei Dou Navigation Satellite System(BDS). Based on the three frequencies of the BDS, three...An investigation has been made on the models and characteristics of triple-frequency carrier-phase linear combinations for the Bei Dou Navigation Satellite System(BDS). Based on the three frequencies of the BDS, three categories of combinations are developed: ionosphere-free combinations(i.e., those that eliminate the ionospheric effect), minimum-noise combinations(those that mitigate the effects of thermal noise and multiple paths), and troposphere-free combinations(those that mitigate tropospheric effects). Both the ionosphere-free and troposphere-free combinations can be expressed as planes, whereas the minimum-noise combinations can be expressed as a line. The relationships between these three categories of linear combinations are investigated from the perspective of geometry. The angle between the troposphere-free plane and ionosphere-free plane is small, while the angles between the troposphere-free plane and the minimum-noise line, and between the ionosphere-free plane and the minimum-noise line, are large. Specifically, the troposphere-free plane is orthogonal to the minimum-noise line. By introducing the concepts of lane number and integer ionosphere number, the characteristics of the long-wavelength integer combinations and ionosphere-free integer combinations are investigated. The analysis indicates that the longest wavelength that can be formed for integer combinations is 146.53 m, and the ionosphere-free integer combinations all have large noise amplification factors. The ionosphere-free integer combination with minimum noise amplification factor is(0, 62, 59). According to the lane number, integer ionosphere number, and noise amplification factor, optimal integer combinations with different characteristics are presented. For general short baselines and long baselines, three independent integer combinations are suggested.展开更多
The operation parameters (vibration, shaft displacement and pressure fluctuation) of No. 1 Francis reversible unit of Baoquan pumped-storage power station were measured on site in the no-load mode at net heads of 51...The operation parameters (vibration, shaft displacement and pressure fluctuation) of No. 1 Francis reversible unit of Baoquan pumped-storage power station were measured on site in the no-load mode at net heads of 518.04, 522.01 and 530.38 m, re- spectively. The rotational speed fluctuations in the no-load mode at three net heads were beyond synchronization requirement with obvious S-shaped characteristic, and misaligned guide vanes (MGV) had to be put into use for synchronization. Further analysis demonstrated that the rotating frequency signal was generally dominant in vibration and shaft displacement mixing signal in the no-load mode, while the frequency domain was wide without an obvious main frequency in pressure fluctuation mixing signal. Besides, the SSTκ-ω turbulence model was adopted to simulate the four quadrant characteristic curves of Baoquan model pump-turbine at three gate openings, and the relative error between simulation results and model test data was within ±6%, indicating that the simulation method in this paper is feasible and S-shaped characteristic of the pump-turbine can be simulated with CFD method.展开更多
In this study we quantify and analyze different components of nocturnal losses from a heated greenhouse with the presence of vegetation for typical winter weather conditions in Marrakesh-Morocco,using a non linear mod...In this study we quantify and analyze different components of nocturnal losses from a heated greenhouse with the presence of vegetation for typical winter weather conditions in Marrakesh-Morocco,using a non linear model,based on the greenhouse heat and mass balance.It was found that 12% of the total input heat was dissipate as a sensible and latent leakage losses,66% was lost by convective exchange through air-inner cover.This gain of energy at the inner-cover is dissipated at the outer-cover by radiation(66%)and convection(34%).This results point toward some practical measures to reduce heat losses:increasing air tightness,using covering materials with low-emissivity in the long wave band or putting up an external thermal curtain should provide significant energy savings.展开更多
Purpose: The aim of this study was to analyze the trend of road traffic fatalities in Kashan Region, lran, in a period of eight years. Methods: Through a cross-sectional study, all road traffic deaths classified und...Purpose: The aim of this study was to analyze the trend of road traffic fatalities in Kashan Region, lran, in a period of eight years. Methods: Through a cross-sectional study, all road traffic deaths classified under the VO1-V99 codes according to ICD-10 in Kashan region, central Iran, from March 2006 to March 2013 and population data were collected from the registration system of Kashan University of Medical Sciences. Years of lost life (YLL) and mortality rates were calculated regarding age, gender and year of the accident. Generalized linear model (GLM) with Poisson log-linear link was used to evaluate the effects of the mentioned variables on mortality rate. Results: During the period of the study (8 years), 928 people (767 men) died due to road traffic injuries (RTIs). The total YLL was 20,818. The mortality rate due to RTIs has been declined constantly from 43.1 in March 2006 to 21.1 per 100,000 in March 2013. The highest mortality rate was found in the age group of over 60 years old and the lowest in the age group of 0-14 years old. Both mortality rate and YLL was greater in men than in women. Poisson regression showed that age, gender and year of the accidents had a significant effect on mortality rate (p 〈 0.001 ). Conclusion: Although there has been a constant decline of mortality rate in Kashan area within the study period, the value remains higher than the mean level of Eastern Mediterranean region and the global average, which is a notable fact for policymakers and authorities.展开更多
In this paper, a novel method for linearization of rational second order nonlinear models is discussed. In particular, we discuss an application of the 5 expansion method (created to deal with problems in Quantum Fie...In this paper, a novel method for linearization of rational second order nonlinear models is discussed. In particular, we discuss an application of the 5 expansion method (created to deal with problems in Quantum Field Theory) which will enable both the linearization and perturbation expansion of such equations. Such a method allows for one to quickly obtain the order zero perturbation theory in terms of certain special functions which are governed by linear equations. Higher order perturbation theories can then be obtained in terms of such special functions. One benefit to such a method is that it may be applied even to models without small physical parameters, as the perturbation is given in terms of the degree of nonlinearity, rather than any physical parameter. As an application, we discuss a method of linearizing the six Painlev~ equations by an application of the method. In addition to highlighting the benefits of the method, we discuss certain shortcomings of the method.展开更多
文摘Many systems of fuzzy linear equations do not have solutions when the solution concept is based on α cuts and interval arithmetic. In this paper,we establish the relations between the systems of fuzzy linear equations and the possibilistic linear programming problems and present an alternative method of solving the systems of fuzzy linear equations.
基金Project(41902301)supported by the National Natural Science Foundation of ChinaProject(20201Y185)supported by the Science and Technology Foundation of Guizhou Province,China+2 种基金Project(Z018023)supported by the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,IRSM,CASProject(201822)supported by the Foundation for Young Talents of Guizhou University,ChinaProject(2017-5402)supported by the Mountain Geohazard Prevention R&D Center of Guizhou Province,China。
文摘The cohesion weakening and friction strengthening(CWFS)model for rock reveals the strength components mobilization process during progressive brittle failure process of rock,which is very helpful in understanding mechanical properties of rock.However,the used incremental cyclic loading−unloading compression test for the determination of strength components is very complicated,which limits the application of CWFS model.In this paper,incremental cyclic loading−unloading compression test was firstly carried out to study the evolution of deformation and the strength properties of Beishan granite after various temperatures treated under different confining pressures.We found the axial and lateral unloading modulus are closely related to the applied stress and damage state of rock.Based on these findings,we can accurately determine the plastic strain during the entire failure process using conventional tri-axial compression test data.Furthermore,a strength component(cohesive and frictional strength)determination method was developed using conventional triaxial compression test.Using this method,we analyzed the variation of strength mobilization and deformation properties of Beishan granite after various temperatures treated.At last,a non-simultaneous strength mobilization model for thermally treated granite was obtained and verified by numerical simulation,which demonstrated the effectiveness of the proposed strength determination method.
文摘One of the many issues in utilizing ERP systems in organizations are, in fact, the implementation stage. This study by investigating the common and available methods of implementation, as well as their inefficiencies will provide a new more efficient method. This new method, in fact, will first assess the required time of implementation in each of the units of the organization, and then will take advantage of a spherical model with central core instead of a linear model. These units, with regard to the required time of implementation, will surround this core as in the form of some layers. The circuits are ordered in a way that the further we move from the core towards the external layers, the shorter the required time of implementation will become. This way, the priority of implementing ERP will be assigned with a direction from external layers to internal layers. Eventually, all the experiences of the previous stages will be transferred to the central core, which has the most complexity. Through this method, it is expected that we may prevent the fully parallel issue, which was a dominant and apparent issue in previous models, so that the required time of implementation would decrease.
基金Project supported by the National Key Technology R &D Program(2006BAB01A07)
文摘Using the finite element method and Cole-Cole model for dual-frequency IP method to research numerical simulation, the authors introduced the fundamental principle of the dual-frequency IP method and the boundary value problem and variational equations, then replaced the complex resistivity of the model with the Cole-Cole model's parameters under ignoring the EM effect. Through solving the last linear equations, electric potentials of all the model's points were obtained. With changing model's parameters, the authors got different curves of the Fs and phases. According to the results of the simulation, the algorithm is proved to be correct and adaptable.
基金Project(2006CB705401) supported by the National Basic Research Program of China
文摘The accuracy of nucleation parameter is a critical factor in the simulation of microstructural evolution during dynamic recrystallization(DRX).Based on the flow stress curve under hot deformation conditions,a new approach is proposed to identify the nucleation parameter during DRX.In this approach,a cellular automaton(CA) model is applied to quantitatively simulate the microstructural evolution and flow stress during hot deformation;and adaptive response surface method(ARSM) is applied as optimization model to provide input parameters to CA model and evaluate the outputs of the latter.By taking an oxygen-free high-conductivity(OFHC) copper as an example,the good agreement between the simulation results and the experimental observations demonstrates the availability of the proposed method.
基金Supported by National Natural Science Foundation of China(No.61601039)financially supported by the State Key Research Development Program of China(Grant No.2016YFC0801407)+3 种基金financially supported by the Natural Science Foundation of Beijing Information Science & Technology University(No.1625008)financially supported by the Opening Project of Beijing Key Laboratory of Internet Culture and Digital Dissemination Research(NO.ICDD201607)Open Foundation of State key Laboratory of Networking and Switching Technology(Beijing University of Posts and Telecommunications)(NO.SKLNST-2016-2-08)financially supported by the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(Grant No.CIT&TCD201504056)
文摘Many ontologies are provided to representing semantic sensors data.However,heterogeneity exists in different sensors which makes some service operators of Internet of Thing(IoT) difficult(such as such as semantic inferring,non-linear inverted index establishing,service composing) .There is a great deal of research about sensor ontology alignment dealing with the heterogeneity between the different sensor ontologies,but fewer solutions focus on exploiting syntaxes in a sensor ontology and the pattern of accessing alignments.Our solution infers alignments by extending structural subsumption algorithms to analyze syntaxes in a sensor ontology,and then combines the alignments with the SKOS model to construct the integration sensor ontology,which can be accessed via the IoT.The experiments show that the integration senor ontology in the SKOS model can be utilized via the IoT service,and the accuracy of our prototype,in average,is higher than others over the four real ontologies.
基金Supported partially by the Post Doctoral Natural Science Foundation of China(2013M532118,2015T81082)the National Natural Science Foundation of China(61573364,61273177,61503066)+2 种基金the State Key Laboratory of Synthetical Automation for Process Industriesthe National High Technology Research and Development Program of China(2015AA043802)the Scientific Research Fund of Liaoning Provincial Education Department(L2013272)
文摘Strong mechanical vibration and acoustical signals of grinding process contain useful information related to load parameters in ball mills. It is a challenge to extract latent features and construct soft sensor model with high dimensional frequency spectra of these signals. This paper aims to develop a selective ensemble modeling approach based on nonlinear latent frequency spectral feature extraction for accurate measurement of material to ball volume ratio. Latent features are first extracted from different vibrations and acoustic spectral segments by kernel partial least squares. Algorithms of bootstrap and least squares support vector machines are employed to produce candidate sub-models using these latent features as inputs. Ensemble sub-models are selected based on genetic algorithm optimization toolbox. Partial least squares regression is used to combine these sub-models to eliminate collinearity among their prediction outputs. Results indicate that the proposed modeling approach has better prediction performance than previous ones.
基金Supported by National Key Based Research Project of China under Grant No.2004CB318000National Natural Science Foundation of China under Grant No.10871170
文摘Numerical simulation of antennae is a topic in computational electromagnetism,which is concerned withthe numerical study of Maxwell equations.By discrete exterior calculus and the lattice gauge theory with coefficient R,we obtain the Bianchi identity on prism lattice.By defining an inner product of discrete differential forms,we derivethe source equation and continuity equation.Those equations compose the discrete Maxwell equations in vacuum caseon discrete manifold,which are implemented on Java development platform to simulate the Gaussian pulse radiation onantennaes.
文摘In this paper, a new control method for synchronous motor with excitation and damper windings is presented. It is based on one type of nonlinear control; feedback linearization control. To make a realization in the sense of electric drive, symmetricM space vector PWM (pulse width modulation) is applied. Estimation of damper winding currents via Lyapunov function for the whole estimated system is done. The aim of control is to make tracking system for rotor speed and square of stator flux. Simulation of motor starting to predefined operating points is done, and also maintaining these points during step change of load torque is obtained. Simulations give good results.
文摘Dried anaerobic granular sludge (DAGS) for removing phenol (organic) and lead (inorganic) pollutants from synthetic wastewater was examined in a fixed bed system. A general rate multi-component model has been built to predict the fixed bed breakthrough curves for single and dual-component system. This model considers both external and internal mass transfer resistances as well as axial dispersion with non-liner multi-component isotherm. The equilibrium isotherm model parameters such as isotherm model constants (qm and b), pore diffusion coefficients (Dp) were obtained from batch experiments, while the external mass transfer coefficients and axial dispersion (kf, Dz) were calculated from empirical correlations. The results show that the general rate multi-component model was found suitable for describing the biosorption process of the dynamic behavior of the DAGS adsorber column and that DAGS can be used efficiently to remove organic and inorganic pollutants.
基金Project supported by the National Natural Science Foundation of China (Nos. 30570053 and 40501037)the National High Technology Research and Development Program (863 Program) of China (No. 2007AA10Z409)+1 种基金the National"Eleventh Five Years Plan" Key Project on Science and Technology of China (No. 2006BAJ08B01)the Research Fund of Science and Technology Bureau of Zhejiang Province,China (No. 2008C23088)
文摘The actinomycete populations and functions in cadmium (Cd) contaminated soil were investigated by the cultivation- independent molecular methods. The genomic DNA was extracted and purified from soil adulterated with various con- centrations of Cd in the laboratory. The partial 16S rDNA genes were amplified by polymerase chain reaction (PCR) using specific primers bound to evolutionarily conserved regions within these actinomycete genes. The diversity in PCR- amplified products, as measured by denaturing gradient gel electrophoresis (EGGE), was used as a genetic fingerprint of the population. Principle component analysis and Shannon-Weaver diversity index (H) analyses were used to analyze the DGGE results. Results showed that the two principal components accounted for only a low level of the total variance. The value H in contaminated soil was lower than that in the control at later stages of cultivation, whereas at earlier stages it was higher. Among the six sampling time points, the first, fifth and sixth weeks had the highest values of H. Significantly negative correlations between bioavallable Cd concentration and H values existed in the samples from weeks 2 (R = 0.929, P 〈 0.05) and 4 (R = 0.909, P 〈 0.05). These results may shed light on the effect of Cd on the soil environment and the chemical behavior and toxicity of Cd to actinomycetes.
基金National Natural Science Foundation of China (No. 51174202)Doctoral Fund of Ministry of Education of China (No. 20100095110013)
文摘A model that rapidly predicts the density components of raw coal is described.It is based on a threegrade fast float/sink test.The recent comprehensive monthly floating and sinking data are used for comparison.The predicted data are used to draw washability curves and to provide a rapid evaluation of the effect from heavy medium induced separation.Thirty-one production shifts worth of fast float/sink data and the corresponding quick ash data are used to verify the model.The results show a small error with an arithmetic average of 0.53 and an absolute average error of 1.50.This indicates that this model has high precision.The theoretical yield from the washability curves is 76.47% for the monthly comprehensive data and 81.31% using the model data.This is for a desired cleaned coal ash of 9%.The relative error between these two is 6.33%,which is small and indicates that the predicted data can be used to rapidly evaluate the separation effect of gravity separation equipment.
基金sponsored by the National Natural Science Foundation of China(Grant Nos.41074024,41204030)the National Basic Research Program of China(Grant No.2013CB733301)
文摘An investigation has been made on the models and characteristics of triple-frequency carrier-phase linear combinations for the Bei Dou Navigation Satellite System(BDS). Based on the three frequencies of the BDS, three categories of combinations are developed: ionosphere-free combinations(i.e., those that eliminate the ionospheric effect), minimum-noise combinations(those that mitigate the effects of thermal noise and multiple paths), and troposphere-free combinations(those that mitigate tropospheric effects). Both the ionosphere-free and troposphere-free combinations can be expressed as planes, whereas the minimum-noise combinations can be expressed as a line. The relationships between these three categories of linear combinations are investigated from the perspective of geometry. The angle between the troposphere-free plane and ionosphere-free plane is small, while the angles between the troposphere-free plane and the minimum-noise line, and between the ionosphere-free plane and the minimum-noise line, are large. Specifically, the troposphere-free plane is orthogonal to the minimum-noise line. By introducing the concepts of lane number and integer ionosphere number, the characteristics of the long-wavelength integer combinations and ionosphere-free integer combinations are investigated. The analysis indicates that the longest wavelength that can be formed for integer combinations is 146.53 m, and the ionosphere-free integer combinations all have large noise amplification factors. The ionosphere-free integer combination with minimum noise amplification factor is(0, 62, 59). According to the lane number, integer ionosphere number, and noise amplification factor, optimal integer combinations with different characteristics are presented. For general short baselines and long baselines, three independent integer combinations are suggested.
文摘The operation parameters (vibration, shaft displacement and pressure fluctuation) of No. 1 Francis reversible unit of Baoquan pumped-storage power station were measured on site in the no-load mode at net heads of 518.04, 522.01 and 530.38 m, re- spectively. The rotational speed fluctuations in the no-load mode at three net heads were beyond synchronization requirement with obvious S-shaped characteristic, and misaligned guide vanes (MGV) had to be put into use for synchronization. Further analysis demonstrated that the rotating frequency signal was generally dominant in vibration and shaft displacement mixing signal in the no-load mode, while the frequency domain was wide without an obvious main frequency in pressure fluctuation mixing signal. Besides, the SSTκ-ω turbulence model was adopted to simulate the four quadrant characteristic curves of Baoquan model pump-turbine at three gate openings, and the relative error between simulation results and model test data was within ±6%, indicating that the simulation method in this paper is feasible and S-shaped characteristic of the pump-turbine can be simulated with CFD method.
基金the financial support of the CNRST as part of Program URAC,Convention URAC28
文摘In this study we quantify and analyze different components of nocturnal losses from a heated greenhouse with the presence of vegetation for typical winter weather conditions in Marrakesh-Morocco,using a non linear model,based on the greenhouse heat and mass balance.It was found that 12% of the total input heat was dissipate as a sensible and latent leakage losses,66% was lost by convective exchange through air-inner cover.This gain of energy at the inner-cover is dissipated at the outer-cover by radiation(66%)and convection(34%).This results point toward some practical measures to reduce heat losses:increasing air tightness,using covering materials with low-emissivity in the long wave band or putting up an external thermal curtain should provide significant energy savings.
文摘Purpose: The aim of this study was to analyze the trend of road traffic fatalities in Kashan Region, lran, in a period of eight years. Methods: Through a cross-sectional study, all road traffic deaths classified under the VO1-V99 codes according to ICD-10 in Kashan region, central Iran, from March 2006 to March 2013 and population data were collected from the registration system of Kashan University of Medical Sciences. Years of lost life (YLL) and mortality rates were calculated regarding age, gender and year of the accident. Generalized linear model (GLM) with Poisson log-linear link was used to evaluate the effects of the mentioned variables on mortality rate. Results: During the period of the study (8 years), 928 people (767 men) died due to road traffic injuries (RTIs). The total YLL was 20,818. The mortality rate due to RTIs has been declined constantly from 43.1 in March 2006 to 21.1 per 100,000 in March 2013. The highest mortality rate was found in the age group of over 60 years old and the lowest in the age group of 0-14 years old. Both mortality rate and YLL was greater in men than in women. Poisson regression showed that age, gender and year of the accidents had a significant effect on mortality rate (p 〈 0.001 ). Conclusion: Although there has been a constant decline of mortality rate in Kashan area within the study period, the value remains higher than the mean level of Eastern Mediterranean region and the global average, which is a notable fact for policymakers and authorities.
文摘In this paper, a novel method for linearization of rational second order nonlinear models is discussed. In particular, we discuss an application of the 5 expansion method (created to deal with problems in Quantum Field Theory) which will enable both the linearization and perturbation expansion of such equations. Such a method allows for one to quickly obtain the order zero perturbation theory in terms of certain special functions which are governed by linear equations. Higher order perturbation theories can then be obtained in terms of such special functions. One benefit to such a method is that it may be applied even to models without small physical parameters, as the perturbation is given in terms of the degree of nonlinearity, rather than any physical parameter. As an application, we discuss a method of linearizing the six Painlev~ equations by an application of the method. In addition to highlighting the benefits of the method, we discuss certain shortcomings of the method.