GP algorithm of correlation dimension computation is ameliorated which overcomes the shortage of traditional one. Improved process of GP algorithm takes the influence of temporal correlative pairs of points on correla...GP algorithm of correlation dimension computation is ameliorated which overcomes the shortage of traditional one. Improved process of GP algorithm takes the influence of temporal correlative pairs of points on correlation dimension into account and promotes the computational efficiency prominently. Iterative SVD method is applied to remove the influence of noise on the result of correlation dimension. The faults of steam flow turbulence and oil film disturbance which occur in 600 MW Steam Turbine Generator are analyzed and whose correlation dimensions are computed. More distinct quantitative index than FFT is gained to distinguish two faults and it’s of little importance to apply correlation dimension to study the influence of various factors on steam flow turbulence fault for nonexistence of convergent floor in correlation integral curve, which presents a new way to learn the operational function of large capacity steam turbine generator and carry out comprehensive condition monitoring.展开更多
By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consist...By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostruetures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanos-truetures were observed and discussed.展开更多
Predicting evaporation rate is one of important elements for hydrology planning. There are several methods to estimate evaporation from a water surface. The objective of this study was to test the capability of artifi...Predicting evaporation rate is one of important elements for hydrology planning. There are several methods to estimate evaporation from a water surface. The objective of this study was to test the capability of artificial neural networks （ANNs） to predict evaporation using 10 years data set （1999 to 2008） from Ahvaz meteorological station and has been compared with values obtained using pan evaporation. Software Qnet 2000 has been utilized to model the evaporation. The Qnet 2000 was trained with monthly climate data （Solar radiation, minimum and maximum temperature, minimum and maximum relative humidity, and wind velocity） as input. The model was approximately implemented 144 times that finally hyperbolic secant stimulant function of 4 input parameters including minimum temperature, maximum temperature, solar radiation and wind velocity and 6 nodes in hidden layer has been yielded the best outcome. Correlation coefficients （R2） in training and testing sections are to 97.4% and 97.3% respectively. Also maximum errors in training and testing sections equaled to 18% and 24% respectively. Results showed ANNs approach works well for the data set used in this region.展开更多
Refrigeration coefficient, ε, is usually calculated by using the First Law of Thermodynamics. In this paper, a new derivation process is introduced through the combination of the Second Law of Thermodynamics with the...Refrigeration coefficient, ε, is usually calculated by using the First Law of Thermodynamics. In this paper, a new derivation process is introduced through the combination of the Second Law of Thermodynamics with the First Law of Thermodynamics. As a result, two new calculation equations for refrigeration coefficient are proposed. One equation is equivalent to the common method, but its form is a little complicated for real calculation. Another equation is the further simplification, and can be used to calculate the refrigeration coefficient instead of common method with a oermit error.展开更多
在气液两相流VOF(volume of fluid,VOF)模型的基础上耦合CSF(continuum surface force,CSF)表面张力模型,建立了高温平板上的铺展液滴与高温空气中悬浮液滴蒸发过程中内部非稳态流动模型,对液滴蒸发过程中内部非稳态流动进行了研究。基...在气液两相流VOF(volume of fluid,VOF)模型的基础上耦合CSF(continuum surface force,CSF)表面张力模型,建立了高温平板上的铺展液滴与高温空气中悬浮液滴蒸发过程中内部非稳态流动模型,对液滴蒸发过程中内部非稳态流动进行了研究。基于相变理论,采用用户自定义函数将流体相变模型加入非稳态流动模型中进行耦合计算,获得了高温平板上的铺展液滴与高温空气中悬浮液滴蒸发过程中的内部流动及变化过程。液滴蒸发过程中非稳态内部流动由液滴表面的温度梯度引发,Marangoni流动在液滴内部形成的时间非常短,流体从液滴表面高温区域流向低温区域。计算结果表明:高温平板上随着液滴蒸发的进行,液滴内部一直保持两个对称的涡流,Marangoni流动比较稳定;高温空气环境中随着液滴蒸发的进行,液滴内部四个涡流逐渐转变成两个对称的涡流;液滴内部温度分布因Marangoni流动加强传热而变得均匀,同时由于温度分布变得均匀,Marangoni流动被削弱。展开更多
A new evaporative cooling system based on the action of centrifugal forces is proposed.Such systems are suitable for cooling large air volumes in tropical climates.Effects of geometrical and operational parameters on ...A new evaporative cooling system based on the action of centrifugal forces is proposed.Such systems are suitable for cooling large air volumes in tropical climates.Effects of geometrical and operational parameters on system performance are optimized using Taguchi method.It is observed that disc speed,air flow rate and water flow rate are found to have major influence on system performance and other parameter,viz.,disc diameter,pin geometry,evaporation chamber length and orientation of pin have less influence.展开更多
Dear Editor, Shortly after initiating the ＂Physical Anthropological Re- search on Han Chinese＂ research project, we applied uni- form sampling methods as well as methods and instruments of measurement to obtain a co...Dear Editor, Shortly after initiating the ＂Physical Anthropological Re- search on Han Chinese＂ research project, we applied uni- form sampling methods as well as methods and instruments of measurement to obtain a complete set of measurements of physical anthropological indicators among Han popula- tions across China. Among these measurements, body stat- ure was a key indicator. Currently, there should be reliable and complete basic data of stature around the Chinese peo- ple. We analyzed the current status of statures among Han adults.展开更多
文摘GP algorithm of correlation dimension computation is ameliorated which overcomes the shortage of traditional one. Improved process of GP algorithm takes the influence of temporal correlative pairs of points on correlation dimension into account and promotes the computational efficiency prominently. Iterative SVD method is applied to remove the influence of noise on the result of correlation dimension. The faults of steam flow turbulence and oil film disturbance which occur in 600 MW Steam Turbine Generator are analyzed and whose correlation dimensions are computed. More distinct quantitative index than FFT is gained to distinguish two faults and it’s of little importance to apply correlation dimension to study the influence of various factors on steam flow turbulence fault for nonexistence of convergent floor in correlation integral curve, which presents a new way to learn the operational function of large capacity steam turbine generator and carry out comprehensive condition monitoring.
文摘By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostruetures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanos-truetures were observed and discussed.
文摘Predicting evaporation rate is one of important elements for hydrology planning. There are several methods to estimate evaporation from a water surface. The objective of this study was to test the capability of artificial neural networks （ANNs） to predict evaporation using 10 years data set （1999 to 2008） from Ahvaz meteorological station and has been compared with values obtained using pan evaporation. Software Qnet 2000 has been utilized to model the evaporation. The Qnet 2000 was trained with monthly climate data （Solar radiation, minimum and maximum temperature, minimum and maximum relative humidity, and wind velocity） as input. The model was approximately implemented 144 times that finally hyperbolic secant stimulant function of 4 input parameters including minimum temperature, maximum temperature, solar radiation and wind velocity and 6 nodes in hidden layer has been yielded the best outcome. Correlation coefficients （R2） in training and testing sections are to 97.4% and 97.3% respectively. Also maximum errors in training and testing sections equaled to 18% and 24% respectively. Results showed ANNs approach works well for the data set used in this region.
基金Supported by Shanghai Leading Academic Displine Project(No.B604)
文摘Refrigeration coefficient, ε, is usually calculated by using the First Law of Thermodynamics. In this paper, a new derivation process is introduced through the combination of the Second Law of Thermodynamics with the First Law of Thermodynamics. As a result, two new calculation equations for refrigeration coefficient are proposed. One equation is equivalent to the common method, but its form is a little complicated for real calculation. Another equation is the further simplification, and can be used to calculate the refrigeration coefficient instead of common method with a oermit error.
文摘在气液两相流VOF(volume of fluid,VOF)模型的基础上耦合CSF(continuum surface force,CSF)表面张力模型,建立了高温平板上的铺展液滴与高温空气中悬浮液滴蒸发过程中内部非稳态流动模型,对液滴蒸发过程中内部非稳态流动进行了研究。基于相变理论,采用用户自定义函数将流体相变模型加入非稳态流动模型中进行耦合计算,获得了高温平板上的铺展液滴与高温空气中悬浮液滴蒸发过程中的内部流动及变化过程。液滴蒸发过程中非稳态内部流动由液滴表面的温度梯度引发,Marangoni流动在液滴内部形成的时间非常短,流体从液滴表面高温区域流向低温区域。计算结果表明:高温平板上随着液滴蒸发的进行,液滴内部一直保持两个对称的涡流,Marangoni流动比较稳定;高温空气环境中随着液滴蒸发的进行,液滴内部四个涡流逐渐转变成两个对称的涡流;液滴内部温度分布因Marangoni流动加强传热而变得均匀,同时由于温度分布变得均匀,Marangoni流动被削弱。
文摘A new evaporative cooling system based on the action of centrifugal forces is proposed.Such systems are suitable for cooling large air volumes in tropical climates.Effects of geometrical and operational parameters on system performance are optimized using Taguchi method.It is observed that disc speed,air flow rate and water flow rate are found to have major influence on system performance and other parameter,viz.,disc diameter,pin geometry,evaporation chamber length and orientation of pin have less influence.
基金supported by the National Natural Science Foundation of China(30830062)
文摘Dear Editor, Shortly after initiating the ＂Physical Anthropological Re- search on Han Chinese＂ research project, we applied uni- form sampling methods as well as methods and instruments of measurement to obtain a complete set of measurements of physical anthropological indicators among Han popula- tions across China. Among these measurements, body stat- ure was a key indicator. Currently, there should be reliable and complete basic data of stature around the Chinese peo- ple. We analyzed the current status of statures among Han adults.
