The P-SV wave reflection coefficients in VTI and HTI media were obtained by approximation of the Jilek(2002a and b)equation in orthotropic anisotropic media.An approximate equation for P-SV wave elastic impedance ca...The P-SV wave reflection coefficients in VTI and HTI media were obtained by approximation of the Jilek(2002a and b)equation in orthotropic anisotropic media.An approximate equation for P-SV wave elastic impedance can be derived from the combination of the new coefficients with S-wave elastic impedance(Duffaut et al.,2000).On this basis, the fluid identification factor in weakly anisotropic media was constructed and used to identify the Castagna and Smith(1994)lithologic combination and achieved good results. Finally,we specifically analyzed the anisotropic parameter impacts P-SV wave elastic impedance and fluid factor trends.展开更多
In this article,based on the acoustic measurements of core samples obtained from the low to medium porosity and permeability reservoirs in the WXS Depression,the densities and P and S wave velocities of these core sam...In this article,based on the acoustic measurements of core samples obtained from the low to medium porosity and permeability reservoirs in the WXS Depression,the densities and P and S wave velocities of these core samples were obtained.Then based on these data,a series of elastic parameters were computed.From the basic theory and previous pore fluid research results,we derived a new fluid identification factor(F).Using the relative variations,Ag/w and Ao/w,of the elastic parameters between gas and water saturated samples and between oil and water saturated samples,λρ,σHSFIF,Kρ,λρ-2μρ,and F as quantitative indicators,we evaluate the sensitivity of the different fluid identification factors to identify reservoir fluids and validate the effects by crossplots.These confirm that the new fluid identification factor(F) is more sensitive for distinguishing oil and water than the traditional method and is more favorable for fliud identification in low to medium porosity and permeability reservoirs.展开更多
By adopting the method of controlling parameters this paper describes the construction of various kinds of cubic curve segment and curved surface fragment with rational and non rational parameters, and discusses the ...By adopting the method of controlling parameters this paper describes the construction of various kinds of cubic curve segment and curved surface fragment with rational and non rational parameters, and discusses the relationship between controlling parameters, weighted factors and types, kinds and characteristics of curve segments and curved surface fragments. A mathematical method is provided for CAGD with abundant connotations, broad covering region, convenience, flexibility and direct simplicity.展开更多
A novel MEMS inductor consisting of a planar single crystalline silicon spiral with a copper surface coating as the conductor is presented. Using a silicon-glass anodic bonding and deep etching formation-and-release p...A novel MEMS inductor consisting of a planar single crystalline silicon spiral with a copper surface coating as the conductor is presented. Using a silicon-glass anodic bonding and deep etching formation-and-release process,a 40μm-thick silicon spiral is formed, which is suspended on a glass substrate to eliminate substrate loss. The surfaces of the silicon spiral are coated with highly conformal copper by electroless plating to reduce the resis- tive loss in the conductor,with thin nickel film plated on the surface of the copper layer for final surface passivation. The fabricated inductor exhibits a self-resonance frequency higher than 15GHz,with a quality factor of about 40 and an inductance of over 5nil at 11.3GHz. Simulations based on a compact equivalent circuit model of the inductor and parameter extraction using a characteristic-function approach are carried out,and good agreement with measurements is obtained.展开更多
Aim To build an adaptive fuzzy neural controller and simulate it. Methods\ Fuzzy logic and back propagation(BP) algorithm are combined to utilize their advantages while avoiding the disadvantages. Results and Conclus...Aim To build an adaptive fuzzy neural controller and simulate it. Methods\ Fuzzy logic and back propagation(BP) algorithm are combined to utilize their advantages while avoiding the disadvantages. Results and Conclusion\ Simulation results of the third order plant with disturbances and dead times show the validity of the presented controller. The presented controller can control cases that preceding controllers were unable to control.展开更多
In micro electrical discharge machining (micro EDM), it is difficult for servo controlling the narrow discharge gap with the characters of non-linear and quick change. In this paper, aiming at solving the problems a...In micro electrical discharge machining (micro EDM), it is difficult for servo controlling the narrow discharge gap with the characters of non-linear and quick change. In this paper, aiming at solving the problems above, a self-adaptive fuzzy controller with formulary rule (SAFCFR) is presented based on the dual feedbacks composed by gap electric signal and discharge-ratio statistics. To ensure the properties of self-optimizing and fast stabilization, the formulary rule was designed with a tuning factor. In addition, the fast-convergence algorithms were introduced to adjust control target center and output scale factor. In this way, the normal discharge ratio can tend to the highest value during micro-EDM process. Experimental results show that the proposed algorithms are effective in improving the servo-control performance. According to the drilling-micro-EDM experiments, the machining efficiency is improved by 20% through applying SAFCFR. Moreover, SAFCFR is a prompt way to optimize parameters of discharge-gap servo control.展开更多
This paper studies the mass transfer performance of structured packings in the absorption of CO2 from air with aqueous Na OH solution. The Eight structured packings tested are sheet metal ones with corrugations of dif...This paper studies the mass transfer performance of structured packings in the absorption of CO2 from air with aqueous Na OH solution. The Eight structured packings tested are sheet metal ones with corrugations of different geometry parameters. Effective mass transfer area and overall gas phase mass transfer coefficient have been measured in an absorption column of 200 mm diameter under the conditions of gas F-factor in 0.38–1.52 Pa0.5and aqueous Na OH solution concentration of 0.10–0.15 kmol·m-3. The effects of gas/liquid phase flow rates and packing geometry parameters are also investigated. The results show that the effective mass transfer area changes not only with packing geometry parameters and liquid load, but also with gas F-factor. A new effective mass transfer area correlation on the gas F-factor and the liquid load was proposed, which is found to fit experiment data very well.展开更多
In order to investigate the feasibility of monitoring the fatigue cracks in turbine blades using acoustic emission (AE) technique, the AE characteristics of fatigue crack growth were studied in the laboratory. And the...In order to investigate the feasibility of monitoring the fatigue cracks in turbine blades using acoustic emission (AE) technique, the AE characteristics of fatigue crack growth were studied in the laboratory. And the characteristics were compared with those of background noise received from a real hydraulic turbine unit. It is found that the AE parameters such as the energy and duration can qualitatively describe the fatigue state of the blades. The correlations of crack propagation rates and acoustic emission count rates vs stress intensity factor (SIF) range are also obtained. At the same time, for the specimens of 20SiMn under the given testing conditions, it is noted that the rise time and duration of events emitted from the fatigue process are lower than those from the background noise; amplitude range is 49-74 dB, which is lower than that of the noise (90-99 dB); frequency range of main energy of crack signals is higher than 60 kHz while that in the noise is lower than 55 kHz. Thus, it is possible to extract the useful crack signals from the noise through appropriate signal processing methods and to represent the crack status of blade materials by AE parameters. As a result, it is feasible to monitor the safety of runners using AE technique.展开更多
The abundance of beneficial insects in the paddy field can be influenced by the abundance of insect pests, water parameters, climatic factors and plant traits. This study was conducted to determine effects of water pa...The abundance of beneficial insects in the paddy field can be influenced by the abundance of insect pests, water parameters, climatic factors and plant traits. This study was conducted to determine effects of water parameters, climatic factors and plant traits on abundant insects. Findings of the studies showed that there were significant correlations between all beneficial insects in paddy field and water parameters tested, namely, water temperature, salinity, turbidity, pH, dissolved oxygen, biological oxygen demand, chemical oxygen demand, ammonia and total suspended solids. Moreover, the selected water parameters of water temperature, dissolved oxygen, biological oxygen demand and chemical oxygen demand were good predictors for abundant beneficial insects in paddy field at Sungai Burong, specifically for insects of sub-orders Anisoptera and Zygoptera, and insects from families Gerridae and Coccinellidae. The plant height, insect pest, temperature, rainfall and humidity were found to be good predictors on the abundance of beneficial insects; nevertheless, the R2 value of multiple regression models was relatively low due to significant relationship between water parameters and insects. Consideration factors of water parameters, climatic factors and plant traits were strongly correlated with those parameters and abundance of insects in the paddy field at Sungai Burong, Tanjung Karang, Selangor.展开更多
The dependence of the organic solar cells parameters, e.g., the shirt circuit current Isc, open circuit voltage Vo,., the fill factor FF and the efficiency eta on temperature is investigated. By expressing the differe...The dependence of the organic solar cells parameters, e.g., the shirt circuit current Isc, open circuit voltage Vo,., the fill factor FF and the efficiency eta on temperature is investigated. By expressing the different equations which link the parameters with temperature, it is observed that the short circuit current Isc increases so monotonous with temperature and then saturates to a maximum value before decreasing at high temperatures. The open circuit voltage V∝ decreases linearly with the increasing of the temperature. The fill factor FF and the efficiency eta which are directly related with short circuit current Isc and the open circuit voltage V∝ follow their variations.展开更多
Elastic wave inverse scattering theory plays an important role in parameters estimation of heterogeneous media.Combining inverse scattering theory,perturbation theory and stationary phase approximation,we derive the P...Elastic wave inverse scattering theory plays an important role in parameters estimation of heterogeneous media.Combining inverse scattering theory,perturbation theory and stationary phase approximation,we derive the P-wave seismic scattering coefficient equation in terms of fluid factor,shear modulus and density of background homogeneous media and perturbation media.With this equation as forward solver,a pre-stack seismic Bayesian inversion method is proposed to estimate the fluid factor of heterogeneous media.In this method,Cauchy distribution is utilized to the ratios of fluid factors,shear moduli and densities of perturbation media and background homogeneous media,respectively.Gaussian distribution is utilized to the likelihood function.The introduction of constraints from initial smooth models enhances the stability of the estimation of model parameters.Model test and real data example demonstrate that the proposed method is able to estimate the fluid factor of heterogeneous media from pre-stack seismic data directly and reasonably.展开更多
This paper is devoted to studing the accelerated expansion of the universe in context of f(T) theory of gravity. For this purpose, we construct different f(T) models and investigate their cosmological behavior thr...This paper is devoted to studing the accelerated expansion of the universe in context of f(T) theory of gravity. For this purpose, we construct different f(T) models and investigate their cosmological behavior through equation of state parameter by using holographic, new agegraphic and their power-law entropy corrected dark energy models. We discuss the graphical behavior of this parameter versus redshif~ for particular values of constant parameters in Bianchi type I universe model. It is shown that the universe lies in different forms of dark energy, namely quintessence, phantom, and quintom corresponding to the chosen scale factors, which depend upon the constant parameters of the models.展开更多
基金sponsored by the National 973 Program(Grant No.2007CB209603)
文摘The P-SV wave reflection coefficients in VTI and HTI media were obtained by approximation of the Jilek(2002a and b)equation in orthotropic anisotropic media.An approximate equation for P-SV wave elastic impedance can be derived from the combination of the new coefficients with S-wave elastic impedance(Duffaut et al.,2000).On this basis, the fluid identification factor in weakly anisotropic media was constructed and used to identify the Castagna and Smith(1994)lithologic combination and achieved good results. Finally,we specifically analyzed the anisotropic parameter impacts P-SV wave elastic impedance and fluid factor trends.
基金supported by the the Key Project of Chinese Ministry of Education (Grant No.109035)the National Natural Science Foundation Key Project (Grant No.40830423)Key Projects of Students Extra-curricular Science and Technology Research Program of Schlumberger (Grant No.SLBX0908)
文摘In this article,based on the acoustic measurements of core samples obtained from the low to medium porosity and permeability reservoirs in the WXS Depression,the densities and P and S wave velocities of these core samples were obtained.Then based on these data,a series of elastic parameters were computed.From the basic theory and previous pore fluid research results,we derived a new fluid identification factor(F).Using the relative variations,Ag/w and Ao/w,of the elastic parameters between gas and water saturated samples and between oil and water saturated samples,λρ,σHSFIF,Kρ,λρ-2μρ,and F as quantitative indicators,we evaluate the sensitivity of the different fluid identification factors to identify reservoir fluids and validate the effects by crossplots.These confirm that the new fluid identification factor(F) is more sensitive for distinguishing oil and water than the traditional method and is more favorable for fliud identification in low to medium porosity and permeability reservoirs.
文摘By adopting the method of controlling parameters this paper describes the construction of various kinds of cubic curve segment and curved surface fragment with rational and non rational parameters, and discusses the relationship between controlling parameters, weighted factors and types, kinds and characteristics of curve segments and curved surface fragments. A mathematical method is provided for CAGD with abundant connotations, broad covering region, convenience, flexibility and direct simplicity.
文摘A novel MEMS inductor consisting of a planar single crystalline silicon spiral with a copper surface coating as the conductor is presented. Using a silicon-glass anodic bonding and deep etching formation-and-release process,a 40μm-thick silicon spiral is formed, which is suspended on a glass substrate to eliminate substrate loss. The surfaces of the silicon spiral are coated with highly conformal copper by electroless plating to reduce the resis- tive loss in the conductor,with thin nickel film plated on the surface of the copper layer for final surface passivation. The fabricated inductor exhibits a self-resonance frequency higher than 15GHz,with a quality factor of about 40 and an inductance of over 5nil at 11.3GHz. Simulations based on a compact equivalent circuit model of the inductor and parameter extraction using a characteristic-function approach are carried out,and good agreement with measurements is obtained.
文摘Aim To build an adaptive fuzzy neural controller and simulate it. Methods\ Fuzzy logic and back propagation(BP) algorithm are combined to utilize their advantages while avoiding the disadvantages. Results and Conclusion\ Simulation results of the third order plant with disturbances and dead times show the validity of the presented controller. The presented controller can control cases that preceding controllers were unable to control.
基金Supported by the National High Technology Research and Development Program of China (No. 2007AA04Z346) , the National Natural Science Foundation of China ( No. 50905094) and China Postdoctoral Science Foundation ( No. 20080440378, 200902097).
文摘In micro electrical discharge machining (micro EDM), it is difficult for servo controlling the narrow discharge gap with the characters of non-linear and quick change. In this paper, aiming at solving the problems above, a self-adaptive fuzzy controller with formulary rule (SAFCFR) is presented based on the dual feedbacks composed by gap electric signal and discharge-ratio statistics. To ensure the properties of self-optimizing and fast stabilization, the formulary rule was designed with a tuning factor. In addition, the fast-convergence algorithms were introduced to adjust control target center and output scale factor. In this way, the normal discharge ratio can tend to the highest value during micro-EDM process. Experimental results show that the proposed algorithms are effective in improving the servo-control performance. According to the drilling-micro-EDM experiments, the machining efficiency is improved by 20% through applying SAFCFR. Moreover, SAFCFR is a prompt way to optimize parameters of discharge-gap servo control.
基金Supported by the National Natural Science Foundation of China(51134017)and Petro China(2011E-24-09)
文摘This paper studies the mass transfer performance of structured packings in the absorption of CO2 from air with aqueous Na OH solution. The Eight structured packings tested are sheet metal ones with corrugations of different geometry parameters. Effective mass transfer area and overall gas phase mass transfer coefficient have been measured in an absorption column of 200 mm diameter under the conditions of gas F-factor in 0.38–1.52 Pa0.5and aqueous Na OH solution concentration of 0.10–0.15 kmol·m-3. The effects of gas/liquid phase flow rates and packing geometry parameters are also investigated. The results show that the effective mass transfer area changes not only with packing geometry parameters and liquid load, but also with gas F-factor. A new effective mass transfer area correlation on the gas F-factor and the liquid load was proposed, which is found to fit experiment data very well.
基金Project(50465002) supported by the National Natural Science Foundation of China
文摘In order to investigate the feasibility of monitoring the fatigue cracks in turbine blades using acoustic emission (AE) technique, the AE characteristics of fatigue crack growth were studied in the laboratory. And the characteristics were compared with those of background noise received from a real hydraulic turbine unit. It is found that the AE parameters such as the energy and duration can qualitatively describe the fatigue state of the blades. The correlations of crack propagation rates and acoustic emission count rates vs stress intensity factor (SIF) range are also obtained. At the same time, for the specimens of 20SiMn under the given testing conditions, it is noted that the rise time and duration of events emitted from the fatigue process are lower than those from the background noise; amplitude range is 49-74 dB, which is lower than that of the noise (90-99 dB); frequency range of main energy of crack signals is higher than 60 kHz while that in the noise is lower than 55 kHz. Thus, it is possible to extract the useful crack signals from the noise through appropriate signal processing methods and to represent the crack status of blade materials by AE parameters. As a result, it is feasible to monitor the safety of runners using AE technique.
文摘The abundance of beneficial insects in the paddy field can be influenced by the abundance of insect pests, water parameters, climatic factors and plant traits. This study was conducted to determine effects of water parameters, climatic factors and plant traits on abundant insects. Findings of the studies showed that there were significant correlations between all beneficial insects in paddy field and water parameters tested, namely, water temperature, salinity, turbidity, pH, dissolved oxygen, biological oxygen demand, chemical oxygen demand, ammonia and total suspended solids. Moreover, the selected water parameters of water temperature, dissolved oxygen, biological oxygen demand and chemical oxygen demand were good predictors for abundant beneficial insects in paddy field at Sungai Burong, specifically for insects of sub-orders Anisoptera and Zygoptera, and insects from families Gerridae and Coccinellidae. The plant height, insect pest, temperature, rainfall and humidity were found to be good predictors on the abundance of beneficial insects; nevertheless, the R2 value of multiple regression models was relatively low due to significant relationship between water parameters and insects. Consideration factors of water parameters, climatic factors and plant traits were strongly correlated with those parameters and abundance of insects in the paddy field at Sungai Burong, Tanjung Karang, Selangor.
文摘The dependence of the organic solar cells parameters, e.g., the shirt circuit current Isc, open circuit voltage Vo,., the fill factor FF and the efficiency eta on temperature is investigated. By expressing the different equations which link the parameters with temperature, it is observed that the short circuit current Isc increases so monotonous with temperature and then saturates to a maximum value before decreasing at high temperatures. The open circuit voltage V∝ decreases linearly with the increasing of the temperature. The fill factor FF and the efficiency eta which are directly related with short circuit current Isc and the open circuit voltage V∝ follow their variations.
基金supported by the National Basic Research Program of China(Grant No.2013CB228604)the National Grand Project for Science and Technology(Grant Nos.2011ZX05030-004-002,2011ZX05019-003&2011ZX05006-002)
文摘Elastic wave inverse scattering theory plays an important role in parameters estimation of heterogeneous media.Combining inverse scattering theory,perturbation theory and stationary phase approximation,we derive the P-wave seismic scattering coefficient equation in terms of fluid factor,shear modulus and density of background homogeneous media and perturbation media.With this equation as forward solver,a pre-stack seismic Bayesian inversion method is proposed to estimate the fluid factor of heterogeneous media.In this method,Cauchy distribution is utilized to the ratios of fluid factors,shear moduli and densities of perturbation media and background homogeneous media,respectively.Gaussian distribution is utilized to the likelihood function.The introduction of constraints from initial smooth models enhances the stability of the estimation of model parameters.Model test and real data example demonstrate that the proposed method is able to estimate the fluid factor of heterogeneous media from pre-stack seismic data directly and reasonably.
文摘This paper is devoted to studing the accelerated expansion of the universe in context of f(T) theory of gravity. For this purpose, we construct different f(T) models and investigate their cosmological behavior through equation of state parameter by using holographic, new agegraphic and their power-law entropy corrected dark energy models. We discuss the graphical behavior of this parameter versus redshif~ for particular values of constant parameters in Bianchi type I universe model. It is shown that the universe lies in different forms of dark energy, namely quintessence, phantom, and quintom corresponding to the chosen scale factors, which depend upon the constant parameters of the models.