The TiO2-water based nanofluid flow in a channel bounded by two porous plates under an oblique magnetic field and variable thermal conductivity is formulated as a boundary-value problem(BVP). The BVP is analytically s...The TiO2-water based nanofluid flow in a channel bounded by two porous plates under an oblique magnetic field and variable thermal conductivity is formulated as a boundary-value problem(BVP). The BVP is analytically solved with the homotopy analysis method(HAM). The result shows that the concentration of the nanoparticles is independent of the volume fraction of TiO2nanoparticles, the magnetic field intensity, and the angle. It is inversely proportional to the mass diffusivity. The fluid speed decreases whereas the temperature increases when the volume fraction of the TiO2nanoparticles increases. This confirms the fact that the occurrence of the TiO2nanoparticles results in the increase in the thermal transfer rate. The fluid speed decreases and the temperature increases for both the pure water and the nanofluid when the magnetic field intensity and angle increase. The maximum velocity does not exist at the middle of the symmetric channel, which is in contrast to the plane-Poiseuille flow, but it deviates a little bit towards the lower plate, which absorbs the fluid with a very low suction velocity. If this suction velocity is increased, the temperature in the vicinity of the lower plate will be increased.An explicit expression for the friction factor-Reynolds number is then developed. It is shown that the Hartmann number of the nanofluid is smaller than that of pure water,while the Nusselt number of the nanofluid is larger than that of pure water. However,both the parameters increase if the magnetic field intensity increases.展开更多
HgCr2S4 is a typical compound manifesting competing ferromagnetic （FM） and antiferromagnetic （AFM） exchanges as well as strong spin-lattice coupling. Here we study these effects by intentionally choosing a combina...HgCr2S4 is a typical compound manifesting competing ferromagnetic （FM） and antiferromagnetic （AFM） exchanges as well as strong spin-lattice coupling. Here we study these effects by intentionally choosing a combination of magnetization under external hydrostatic pressure and thermal conductivity at various magnetic fields. Upon applying pressure up to 10 kbar at 1 kOe, while the magnitude of magnetization reduces progressively, the AFM ordering temperature TN enhances concomitantly at a rate of about 1.5 K/kbar. Strikingly, at lO kOe the field polarized FM state is found to be driven readily back to an AFM one even at only 5kbar. In addition, the thermal conductivity exhibits drastic increments at various fields in the temperature range with strong spin fluctuations, reaching about 30% at 50 kOe. Consequently, the results give new experimental evidence of spin-lattice coupling. Apart from the colossal magnetoeapacitance and colossal magnetoresistance reported previously, the findings here may enable new promising functionalities for potential applications.展开更多
During concrete dam construction,concrete temperature monitoring and control is key to ensuring dam concrete quality and construction safety.In this study,a 2D thermal field restructuring method relating to the Krigin...During concrete dam construction,concrete temperature monitoring and control is key to ensuring dam concrete quality and construction safety.In this study,a 2D thermal field restructuring method relating to the Kriging temperature interpolation is proposed.Based on dam site monitoring data of distributed optical fiber,the results indicated that the proposed restructuring method can be applied to effectively and quickly obtain 2D real thermal field.The evolution law of thermal field in early ages and temperature differences of concrete blocks based on the thermal field data are obtained.It also can be concluded that the proposed restructuring method could help obtain accurate and reliable restructuring monitoring data.展开更多
A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperatur...A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater.A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was performed.The nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4m/s flow and saturated from 0.75m/s flow.However the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0m/s.Thus,this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.展开更多
The transmission ratio along the radian direction normal to the joints was studied in the Universal Distinct Element Code （UDEC）. The variation of the transmission ratio with the ratio of joint spacing to wavelength...The transmission ratio along the radian direction normal to the joints was studied in the Universal Distinct Element Code （UDEC）. The variation of the transmission ratio with the ratio of joint spacing to wavelength was generalized into a general curve, which was determined by two critical points. The relationship between the two critical points and the affecting factors, quantity of joints and the normalized normal stiffness of joints, were obtained. A prediction model of the transmission ratio in the radian direction normal to the joints was proposed. The proposed model was applied to a field explosion test. The estimated values of the peak particle velocity from the prediction model were compared with the field records. The comparisons showed that the prediction model of the transmission ratio in the direction normal to the joints in the process of 2-D compressional wave propagation through multiple parallel joints is reliable.展开更多
In previous studies on plasma-particle interaction, as far as we know, the rf plasma flow and temperature fields are all simulated by the non-self-consistent one-dimensional electromagnetic (1-D EM) field model. In th...In previous studies on plasma-particle interaction, as far as we know, the rf plasma flow and temperature fields are all simulated by the non-self-consistent one-dimensional electromagnetic (1-D EM) field model. In the present paper, the complete self-consistent two-dimensional electromagnetic (2-D EM) field model in- corporating the axial Lorentz force component, which is neglected in the 1-D model, is firstly adopted to calculate the aluminium particle trajectory and thermal history in atmospheric rf Ar plasma with the particle evaporation effect included. The cru- cial effect of reverse flow within the coil region on the particle trajectory is discovered and the results show that the 2-D EM field model must be adopted instead of the 1-D model when the plasma-particle interaction is studied. The effect of carrier gas flux on the particle movement and heating are also studied, resulting in some useful conclusions for both plasma theory and application.展开更多
A detailed analysis of an exact solvable 2-D model on a super-exchange magnetic system with frustrations in an external magnetic field is given. By means of differentiating the expression of the free energy, various t...A detailed analysis of an exact solvable 2-D model on a super-exchange magnetic system with frustrations in an external magnetic field is given. By means of differentiating the expression of the free energy, various thermodynamic properties of the system have been obtained. The variations of these quantities with applied field H and temperature T are plotted. It is found that the competition among the frustrations, H and T, results in many interesting features. Especially, three kinds of magnetic structures of the system have been obtained for various magnetic fields, and the behaviour of the magnetization as a function of temperature for a fixed magnetic field is rather peculiar.展开更多
采用二维电泳(2-dimensional gel electrophoresis,2-DE)技术对脉冲电场(pulsed electric field,PEF)处理前后哈密瓜汁中酿酒酵母蛋白质进行检测分析,探究处理过程对酿酒酵母蛋白表达的影响。实验结果得知,所有检测出的酵母蛋白等电点...采用二维电泳(2-dimensional gel electrophoresis,2-DE)技术对脉冲电场(pulsed electric field,PEF)处理前后哈密瓜汁中酿酒酵母蛋白质进行检测分析,探究处理过程对酿酒酵母蛋白表达的影响。实验结果得知,所有检测出的酵母蛋白等电点均介于4.00与6.87之间,分子量分布在14.58~109.83 k Da之间;PEF处理后的酿酒酵母为免受环境变化带来的氧化损伤,细胞中硫氧还蛋白过氧化物酶、延长因子2表达上调;并且因场强影响到了细胞的遗传物质,核染色质蛋白和DNA修复蛋白表达上调;此外,细胞中Cu-Zn辅基超氧化物歧化酶和与糖原合成与代谢密切相关的磷酸丙酮酸水合酶的表达下调,反映细胞的活力下降或死亡;与细胞生存和增殖相关蛋白的表达也发生了明显的变化,如胱硫醚β-合酶、腺苷5-单磷酰胺酶、非典型蛋白Ynr034w-A亚基等。PEF处理影响到细胞代谢的相关酶类和遗传物质,可为研究PEF强化杀菌方法提供理论依据。展开更多
Since the General Channel designed for the South-to-North Water Transfer Project in China has to cross many rivers and streams flowing from west to east, there are potentially serious effects additional flooding on th...Since the General Channel designed for the South-to-North Water Transfer Project in China has to cross many rivers and streams flowing from west to east, there are potentially serious effects additional flooding on the western side of the project alignment. Therefore, a 2-D numerical model for forecasting basin flood disasters was established and verified using historical flood data. The model was applied to researching the interaction between the proposed Project and flooding events for 5 streams in the Anyang River reach as a representative case study. Simulated results indicate that the model could correctly forecast the flood, submerged area and depths, and water surface elevations along the left side of the channel. The discharge capacity and location of hydraulic structures in the transfer canal alignment were analyzed. Then adjustments to the dimensions and positioning of proposed hydraulic structures were recommended at intersections, especially the addition of a channel to transfer flood water from one stream to another, which can effectively limit the sluice and protect the Anyang City from flooding.展开更多
文摘The TiO2-water based nanofluid flow in a channel bounded by two porous plates under an oblique magnetic field and variable thermal conductivity is formulated as a boundary-value problem(BVP). The BVP is analytically solved with the homotopy analysis method(HAM). The result shows that the concentration of the nanoparticles is independent of the volume fraction of TiO2nanoparticles, the magnetic field intensity, and the angle. It is inversely proportional to the mass diffusivity. The fluid speed decreases whereas the temperature increases when the volume fraction of the TiO2nanoparticles increases. This confirms the fact that the occurrence of the TiO2nanoparticles results in the increase in the thermal transfer rate. The fluid speed decreases and the temperature increases for both the pure water and the nanofluid when the magnetic field intensity and angle increase. The maximum velocity does not exist at the middle of the symmetric channel, which is in contrast to the plane-Poiseuille flow, but it deviates a little bit towards the lower plate, which absorbs the fluid with a very low suction velocity. If this suction velocity is increased, the temperature in the vicinity of the lower plate will be increased.An explicit expression for the friction factor-Reynolds number is then developed. It is shown that the Hartmann number of the nanofluid is smaller than that of pure water,while the Nusselt number of the nanofluid is larger than that of pure water. However,both the parameters increase if the magnetic field intensity increases.
基金Supported by the National Natural Science Foundation of China under Grant Nos U1332143 and 11574323
文摘HgCr2S4 is a typical compound manifesting competing ferromagnetic （FM） and antiferromagnetic （AFM） exchanges as well as strong spin-lattice coupling. Here we study these effects by intentionally choosing a combination of magnetization under external hydrostatic pressure and thermal conductivity at various magnetic fields. Upon applying pressure up to 10 kbar at 1 kOe, while the magnitude of magnetization reduces progressively, the AFM ordering temperature TN enhances concomitantly at a rate of about 1.5 K/kbar. Strikingly, at lO kOe the field polarized FM state is found to be driven readily back to an AFM one even at only 5kbar. In addition, the thermal conductivity exhibits drastic increments at various fields in the temperature range with strong spin fluctuations, reaching about 30% at 50 kOe. Consequently, the results give new experimental evidence of spin-lattice coupling. Apart from the colossal magnetoeapacitance and colossal magnetoresistance reported previously, the findings here may enable new promising functionalities for potential applications.
基金supported by National Basic Research Program of China(973 Program)Grant No.2011CB013503China Three Gorges Corporation research project(Contract number:WDD/0490)
文摘During concrete dam construction,concrete temperature monitoring and control is key to ensuring dam concrete quality and construction safety.In this study,a 2D thermal field restructuring method relating to the Kriging temperature interpolation is proposed.Based on dam site monitoring data of distributed optical fiber,the results indicated that the proposed restructuring method can be applied to effectively and quickly obtain 2D real thermal field.The evolution law of thermal field in early ages and temperature differences of concrete blocks based on the thermal field data are obtained.It also can be concluded that the proposed restructuring method could help obtain accurate and reliable restructuring monitoring data.
文摘A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater.A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was performed.The nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4m/s flow and saturated from 0.75m/s flow.However the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0m/s.Thus,this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.
基金The work was partially supported by the Major State Basic Research Development Program of China (No. 2002CB412703).
文摘The transmission ratio along the radian direction normal to the joints was studied in the Universal Distinct Element Code （UDEC）. The variation of the transmission ratio with the ratio of joint spacing to wavelength was generalized into a general curve, which was determined by two critical points. The relationship between the two critical points and the affecting factors, quantity of joints and the normalized normal stiffness of joints, were obtained. A prediction model of the transmission ratio in the radian direction normal to the joints was proposed. The proposed model was applied to a field explosion test. The estimated values of the peak particle velocity from the prediction model were compared with the field records. The comparisons showed that the prediction model of the transmission ratio in the direction normal to the joints in the process of 2-D compressional wave propagation through multiple parallel joints is reliable.
文摘In previous studies on plasma-particle interaction, as far as we know, the rf plasma flow and temperature fields are all simulated by the non-self-consistent one-dimensional electromagnetic (1-D EM) field model. In the present paper, the complete self-consistent two-dimensional electromagnetic (2-D EM) field model in- corporating the axial Lorentz force component, which is neglected in the 1-D model, is firstly adopted to calculate the aluminium particle trajectory and thermal history in atmospheric rf Ar plasma with the particle evaporation effect included. The cru- cial effect of reverse flow within the coil region on the particle trajectory is discovered and the results show that the 2-D EM field model must be adopted instead of the 1-D model when the plasma-particle interaction is studied. The effect of carrier gas flux on the particle movement and heating are also studied, resulting in some useful conclusions for both plasma theory and application.
文摘A detailed analysis of an exact solvable 2-D model on a super-exchange magnetic system with frustrations in an external magnetic field is given. By means of differentiating the expression of the free energy, various thermodynamic properties of the system have been obtained. The variations of these quantities with applied field H and temperature T are plotted. It is found that the competition among the frustrations, H and T, results in many interesting features. Especially, three kinds of magnetic structures of the system have been obtained for various magnetic fields, and the behaviour of the magnetization as a function of temperature for a fixed magnetic field is rather peculiar.
文摘采用二维电泳(2-dimensional gel electrophoresis,2-DE)技术对脉冲电场(pulsed electric field,PEF)处理前后哈密瓜汁中酿酒酵母蛋白质进行检测分析,探究处理过程对酿酒酵母蛋白表达的影响。实验结果得知,所有检测出的酵母蛋白等电点均介于4.00与6.87之间,分子量分布在14.58~109.83 k Da之间;PEF处理后的酿酒酵母为免受环境变化带来的氧化损伤,细胞中硫氧还蛋白过氧化物酶、延长因子2表达上调;并且因场强影响到了细胞的遗传物质,核染色质蛋白和DNA修复蛋白表达上调;此外,细胞中Cu-Zn辅基超氧化物歧化酶和与糖原合成与代谢密切相关的磷酸丙酮酸水合酶的表达下调,反映细胞的活力下降或死亡;与细胞生存和增殖相关蛋白的表达也发生了明显的变化,如胱硫醚β-合酶、腺苷5-单磷酰胺酶、非典型蛋白Ynr034w-A亚基等。PEF处理影响到细胞代谢的相关酶类和遗传物质,可为研究PEF强化杀菌方法提供理论依据。
基金the National Natural Science Foundation of China (Grant No. 50779019).
文摘Since the General Channel designed for the South-to-North Water Transfer Project in China has to cross many rivers and streams flowing from west to east, there are potentially serious effects additional flooding on the western side of the project alignment. Therefore, a 2-D numerical model for forecasting basin flood disasters was established and verified using historical flood data. The model was applied to researching the interaction between the proposed Project and flooding events for 5 streams in the Anyang River reach as a representative case study. Simulated results indicate that the model could correctly forecast the flood, submerged area and depths, and water surface elevations along the left side of the channel. The discharge capacity and location of hydraulic structures in the transfer canal alignment were analyzed. Then adjustments to the dimensions and positioning of proposed hydraulic structures were recommended at intersections, especially the addition of a channel to transfer flood water from one stream to another, which can effectively limit the sluice and protect the Anyang City from flooding.
