Based on the method of linear trending,analysis was made upon the daily temperature statistics of Meitan County from 1951 to 2009,and the results showed that the temperature in general was on the rise.With 1980 as the...Based on the method of linear trending,analysis was made upon the daily temperature statistics of Meitan County from 1951 to 2009,and the results showed that the temperature in general was on the rise.With 1980 as the turning point,it was on the decline before while later the temperature increased quickly.Among these figures,the variation rates of annual average temperature,annual maximum temperature,and annual minimum temperature are 0.11 ℃/10 a,0.08 ℃/10 a,and 0.36 ℃/10 a.The variation rates of average temperature in spring,summer,fall and winter are respectively 0.12 ℃/10 a,0.07 ℃/10 a,0.12 ℃/10 a,and 0.13 ℃/10 a.Morlet wavelet was adopted to analyze the periodicity of temperature change which has periods of different scales.But since 2000,during different time scales most of the areas have been in the period of temperature rises.Besides,certain rule exists in the periodicity of maximum temperature and minimum temperature.Before 1970s,they had opposite changing rules,and the alteration of the peak value occurred.However,in the late 1980s,they had similar changing rules,and their peak values appeared at the same time.It means that against the background of global warming,the reaction of temperature evolution in Meitan County is quite remarkable.展开更多
This work focuses on transient thermal behavior of radial fins of rectangular,triangular and hyperbolic profiles with temperature-dependent properties.A hybrid numerical algorithm which combines differential transform...This work focuses on transient thermal behavior of radial fins of rectangular,triangular and hyperbolic profiles with temperature-dependent properties.A hybrid numerical algorithm which combines differential transformation(DTM) and finite difference(FDM) methods is utilized to theoretically study the present problem.DTM and FDM are applied to the time and space domains of the problem,respectively.The accuracy of this method solution is checked against the numerical solution.Then,the effects of some applicable parameters were studied comparatively.Since a broad range of governing parameters are investigated,the results could be useful in a number of industrial and engineering applications.展开更多
The paper presents a Monte Carlo simulation to study the adsorption characteristics of methane molecule on coal slit pores from different aspects.Firstly,a physical model of adsorption and desorption of methane molecu...The paper presents a Monte Carlo simulation to study the adsorption characteristics of methane molecule on coal slit pores from different aspects.Firstly,a physical model of adsorption and desorption of methane molecules on micropores was established.Secondly,a grand canonical ensemble was introduced as the Monte Carlo simulation system.Thirdly,based on the model and system,the molecule simulation program was developed with VC++6.0 to simulate the isothermal adsorption relationship between the amount of molecule absorption and the factors affecting it.Lastly,the numerically simulated results were compared with measured results of adsorption coal samples of two different coal mines with a laboratory gas absorption instrument.The results show that the molecule simulations of the adsorption constants,the adsorption quantity,and the isothermal adsorption curve at the same and different coal temperatures were in good agreement with those measured in the experiments,indicating that it is feasible to use the established model and the Monte Carlo molecule simulation to study the adsorption characteristics of methane molecules in coal.展开更多
The control of ultra-supercritical(USC) power unit is a difficult issue for its characteristic of the nonlinearity, large dead time and coupling of the unit. In this paper, model predictive control(MPC) based on multi...The control of ultra-supercritical(USC) power unit is a difficult issue for its characteristic of the nonlinearity, large dead time and coupling of the unit. In this paper, model predictive control(MPC) based on multi-model and double layered optimization is introduced for coordinated control of USC unit. The linear programming(LP) combined with quadratic programming(QP) is used in steady optimization for computation of the ideal value of dynamic optimization. Three inputs(i.e. valve opening, coal flow and feedwater flow) are employed to control three outputs(i.e. load, main steam temperature and main steam pressure). The step response models for the dynamic matrix control(DMC) are constructed using the three inputs and the three outputs. Piecewise models are built at selected operation points. Double-layered multi-model predictive controller is implemented in simulation with satisfactory performance.展开更多
Polyether and polyether/ester based TPU （thermoplastic polyurethanes） were investigated with wide-angle XRD （X-ray diffraction） and SAXS （small angle X-ray scattering）. Furthermore, SAXS measurements were perfor...Polyether and polyether/ester based TPU （thermoplastic polyurethanes） were investigated with wide-angle XRD （X-ray diffraction） and SAXS （small angle X-ray scattering）. Furthermore, SAXS measurements were performed in the temperature range of 30 ℃ to 130 ℃. Polyether based polymers exhibit only one broad diffraction signal in a region of 2 θ 15° to 25°. In case of polyurethanes with ether/ester modification, the broad diffraction signal arises with small sharp diffraction signals. SAXS measurements of polymers reveal the size and shape of the crystalline zones of the polymer. Between 30 ℃ and 130 ℃ the size of the crystalline zone changes significantly. The size decreases in most of investigated TPU. In the case of Desmopan 9365D an increase of the particle size was observed.展开更多
This paper describes the effects of temperature on the complex intermediate processes from the precursor to the fully-crystallized anatase TiO2 nanoparticles in hydrothermal synthesis. The anatase TiO2 nanoparticles w...This paper describes the effects of temperature on the complex intermediate processes from the precursor to the fully-crystallized anatase TiO2 nanoparticles in hydrothermal synthesis. The anatase TiO2 nanoparticles were synthesized in a wide temperature range below 230°C. The composition, morphology, and methylene blue (MB) decoloration characteristics of the obtained products were investigated by X-ray diffraction, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, and scanning and transmission electron microscope. The dehydrating polycondensation of Ti(IV)-hydrates and the decomposition of (NH4)2Ti3O7 intermediates with the temperature increase lead to the direct formation of anatase TiO2 nanoparticles under the hydrothermal environments. The strong MB decoloration of the hydrothermal products obtained at the low (≤130°C) and high (≥180°C) temperatures are attributed to the adsorption of Ti(IV)-hydrates and the photocatalysis of anatase TiO2 nanoparticles, respectively.展开更多
基金Supported by National Basic Research Program of China (973 Pro-gram) (2010CB951102 )Program of Innovation ResearchGroup (51021006),National Natural Science Foundation of China~~
文摘Based on the method of linear trending,analysis was made upon the daily temperature statistics of Meitan County from 1951 to 2009,and the results showed that the temperature in general was on the rise.With 1980 as the turning point,it was on the decline before while later the temperature increased quickly.Among these figures,the variation rates of annual average temperature,annual maximum temperature,and annual minimum temperature are 0.11 ℃/10 a,0.08 ℃/10 a,and 0.36 ℃/10 a.The variation rates of average temperature in spring,summer,fall and winter are respectively 0.12 ℃/10 a,0.07 ℃/10 a,0.12 ℃/10 a,and 0.13 ℃/10 a.Morlet wavelet was adopted to analyze the periodicity of temperature change which has periods of different scales.But since 2000,during different time scales most of the areas have been in the period of temperature rises.Besides,certain rule exists in the periodicity of maximum temperature and minimum temperature.Before 1970s,they had opposite changing rules,and the alteration of the peak value occurred.However,in the late 1980s,they had similar changing rules,and their peak values appeared at the same time.It means that against the background of global warming,the reaction of temperature evolution in Meitan County is quite remarkable.
文摘This work focuses on transient thermal behavior of radial fins of rectangular,triangular and hyperbolic profiles with temperature-dependent properties.A hybrid numerical algorithm which combines differential transformation(DTM) and finite difference(FDM) methods is utilized to theoretically study the present problem.DTM and FDM are applied to the time and space domains of the problem,respectively.The accuracy of this method solution is checked against the numerical solution.Then,the effects of some applicable parameters were studied comparatively.Since a broad range of governing parameters are investigated,the results could be useful in a number of industrial and engineering applications.
基金supported by the Industrial Research Project in Guizhou Science and Technology Bureau of China (GY(2011)No.3012)International Cooperation Projects in Guizhou Science and Technology Bureau of China (G(2009)No.700111)
文摘The paper presents a Monte Carlo simulation to study the adsorption characteristics of methane molecule on coal slit pores from different aspects.Firstly,a physical model of adsorption and desorption of methane molecules on micropores was established.Secondly,a grand canonical ensemble was introduced as the Monte Carlo simulation system.Thirdly,based on the model and system,the molecule simulation program was developed with VC++6.0 to simulate the isothermal adsorption relationship between the amount of molecule absorption and the factors affecting it.Lastly,the numerically simulated results were compared with measured results of adsorption coal samples of two different coal mines with a laboratory gas absorption instrument.The results show that the molecule simulations of the adsorption constants,the adsorption quantity,and the isothermal adsorption curve at the same and different coal temperatures were in good agreement with those measured in the experiments,indicating that it is feasible to use the established model and the Monte Carlo molecule simulation to study the adsorption characteristics of methane molecules in coal.
基金Supported by the National Natural Science Foundation of China(60974119)
文摘The control of ultra-supercritical(USC) power unit is a difficult issue for its characteristic of the nonlinearity, large dead time and coupling of the unit. In this paper, model predictive control(MPC) based on multi-model and double layered optimization is introduced for coordinated control of USC unit. The linear programming(LP) combined with quadratic programming(QP) is used in steady optimization for computation of the ideal value of dynamic optimization. Three inputs(i.e. valve opening, coal flow and feedwater flow) are employed to control three outputs(i.e. load, main steam temperature and main steam pressure). The step response models for the dynamic matrix control(DMC) are constructed using the three inputs and the three outputs. Piecewise models are built at selected operation points. Double-layered multi-model predictive controller is implemented in simulation with satisfactory performance.
文摘Polyether and polyether/ester based TPU （thermoplastic polyurethanes） were investigated with wide-angle XRD （X-ray diffraction） and SAXS （small angle X-ray scattering）. Furthermore, SAXS measurements were performed in the temperature range of 30 ℃ to 130 ℃. Polyether based polymers exhibit only one broad diffraction signal in a region of 2 θ 15° to 25°. In case of polyurethanes with ether/ester modification, the broad diffraction signal arises with small sharp diffraction signals. SAXS measurements of polymers reveal the size and shape of the crystalline zones of the polymer. Between 30 ℃ and 130 ℃ the size of the crystalline zone changes significantly. The size decreases in most of investigated TPU. In the case of Desmopan 9365D an increase of the particle size was observed.
基金supported by the Ministry of Science and Technology of China (Grant No. 2010CB631004)the Fundamental Research Funds for the Central Universities (Grant Nos. 1112021302, 1106021343, 1116021301)+1 种基金the PAPD and National Natural Science Foundation of China (Grant Nos. 50831004, 11004098, 51171078)the research fund of Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province (Grant No. AE201015)
文摘This paper describes the effects of temperature on the complex intermediate processes from the precursor to the fully-crystallized anatase TiO2 nanoparticles in hydrothermal synthesis. The anatase TiO2 nanoparticles were synthesized in a wide temperature range below 230°C. The composition, morphology, and methylene blue (MB) decoloration characteristics of the obtained products were investigated by X-ray diffraction, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, and scanning and transmission electron microscope. The dehydrating polycondensation of Ti(IV)-hydrates and the decomposition of (NH4)2Ti3O7 intermediates with the temperature increase lead to the direct formation of anatase TiO2 nanoparticles under the hydrothermal environments. The strong MB decoloration of the hydrothermal products obtained at the low (≤130°C) and high (≥180°C) temperatures are attributed to the adsorption of Ti(IV)-hydrates and the photocatalysis of anatase TiO2 nanoparticles, respectively.
