When the electronic temperature sensor was incorporated into a system of soil water tension and the insidetube temperature was monitored in real time, it is concluded that the inside temperature increased by 26.9 ℃ a...When the electronic temperature sensor was incorporated into a system of soil water tension and the insidetube temperature was monitored in real time, it is concluded that the inside temperature increased by 26.9 ℃ and the inside pressure changed about 14.6 Kpa, when the pottery soil was replaced by the sealing plug. When the soil water was relatively stable in the experimental salvers, the in-side pressure stil varied regularly with the temperature. When the inside temperature increased by 22.2 ℃, the inside pressure varied about 7.4 Kpa. Through com-pensation calculation of the inside tension, the temperature in the warming and cooling periods was compensated, which was useful to correct the tension measurement errors induced from the changing temperature. When the measuring interval was 4 hours and the temperature difference was 18.1 ℃, the tension difference of both points was only 0.278 Kpa, compared to the difference up to 6.5 Kpa before compensation.展开更多
[Objective] In order to better meet the requirement of crops on a more and more accurate water content under various planting environment of modern agri-culture, an automatic test system of soil water characteristic c...[Objective] In order to better meet the requirement of crops on a more and more accurate water content under various planting environment of modern agri-culture, an automatic test system of soil water characteristic curve was designed by combining the conceptions of soil moisture content and soil water potential. [Method] Electronic soil moisture tension meter was used to determine the real-time tension value of soil moisture in the tested container, and the electronic Weigh sensor was used to determine soil Weigh. Minusing method was used to calculate soil moisture content, based on which the soil water characteristic curve was plotted. [Result] Through the filed survey of 2 different kinds of soil in Jiangsu Province, the results were as fol ows： soil of different composition showed different trend in soil water characteristic curve that the soil water characteristic relation of the sandy soil in the old course of the Yel ow River in Xuzhou was Y=-0.000 2X3＋0.027 7X2-1.644 5X＋38.161, R2=0.991 9; while the soil water characteristic relation of the saline-alkali soil in Jinhai Farm of Dafeng was Y=-0.00 2X2-0.426X＋39.905, R2=0.991 3. [Con-clusion] The automatic test system of soil water characteristic curve soil water char-acteristics curve could reflect soil moisture content and soil water potential, as wel as reflect the effectiveness of soil water to plant growth, providing basis for the sci-entific irrigation.展开更多
The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemica...The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.展开更多
An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular the...An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular ther-modynamic model has been proposed. The interfacial tension of surfactant-oil-water systems can be calculated from the surface tensions of pure oil and water by this model. The interfacial tension data for sodium dodecyl sulphate-heptane-water system, polyoxyethylene n-octylphenol-heptane-water system and hexadecyl trimethyl ammonium bromide-heptane-water system have been correlated. By using the adjustable parameters obtained, the interfacial tensions of these systems at other temperatures have been predicted. Both the correlated and the predicted values are satisfactory.展开更多
基金Supported by Jiangsu Agricultural Self-innovation Fund[CX(13)3031]~~
文摘When the electronic temperature sensor was incorporated into a system of soil water tension and the insidetube temperature was monitored in real time, it is concluded that the inside temperature increased by 26.9 ℃ and the inside pressure changed about 14.6 Kpa, when the pottery soil was replaced by the sealing plug. When the soil water was relatively stable in the experimental salvers, the in-side pressure stil varied regularly with the temperature. When the inside temperature increased by 22.2 ℃, the inside pressure varied about 7.4 Kpa. Through com-pensation calculation of the inside tension, the temperature in the warming and cooling periods was compensated, which was useful to correct the tension measurement errors induced from the changing temperature. When the measuring interval was 4 hours and the temperature difference was 18.1 ℃, the tension difference of both points was only 0.278 Kpa, compared to the difference up to 6.5 Kpa before compensation.
基金Supported by the Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(CX(13)3031)~~
文摘[Objective] In order to better meet the requirement of crops on a more and more accurate water content under various planting environment of modern agri-culture, an automatic test system of soil water characteristic curve was designed by combining the conceptions of soil moisture content and soil water potential. [Method] Electronic soil moisture tension meter was used to determine the real-time tension value of soil moisture in the tested container, and the electronic Weigh sensor was used to determine soil Weigh. Minusing method was used to calculate soil moisture content, based on which the soil water characteristic curve was plotted. [Result] Through the filed survey of 2 different kinds of soil in Jiangsu Province, the results were as fol ows： soil of different composition showed different trend in soil water characteristic curve that the soil water characteristic relation of the sandy soil in the old course of the Yel ow River in Xuzhou was Y=-0.000 2X3＋0.027 7X2-1.644 5X＋38.161, R2=0.991 9; while the soil water characteristic relation of the saline-alkali soil in Jinhai Farm of Dafeng was Y=-0.00 2X2-0.426X＋39.905, R2=0.991 3. [Con-clusion] The automatic test system of soil water characteristic curve soil water char-acteristics curve could reflect soil moisture content and soil water potential, as wel as reflect the effectiveness of soil water to plant growth, providing basis for the sci-entific irrigation.
基金Supported by the National Key Basic Research Programme (No.973-G1999022505),University of Petroleum Basic Research Fund(No.ZX9904)
文摘The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.
基金Supported by the National Nature Science Foundation of China(No.29736170)
文摘An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular ther-modynamic model has been proposed. The interfacial tension of surfactant-oil-water systems can be calculated from the surface tensions of pure oil and water by this model. The interfacial tension data for sodium dodecyl sulphate-heptane-water system, polyoxyethylene n-octylphenol-heptane-water system and hexadecyl trimethyl ammonium bromide-heptane-water system have been correlated. By using the adjustable parameters obtained, the interfacial tensions of these systems at other temperatures have been predicted. Both the correlated and the predicted values are satisfactory.
