The effect of irrigation water quality on unsaturated hydraulic conductivity (HC) of undisturbed soil in field was studied.Results show that within the operating soil suction range (0-1.6 KPa) of disc permeameters,the...The effect of irrigation water quality on unsaturated hydraulic conductivity (HC) of undisturbed soil in field was studied.Results show that within the operating soil suction range (0-1.6 KPa) of disc permeameters,the higher the electric conductivity (EC) of irrigation water,the higher the soil HC became.The soil HC doubled when EC increased from 0.1 to 6.0ds m^-1.High sodium-adsorption ratio(SAR) of irrigation water would have an unfavorable effect on soil HC.Soil HC decreased with the increasing of SAR,especially in the case of higher soil suction.An interaction existed between the effects of EC and SAR of irrigation water on soil HC.The HC of unsaturated soil dependent upon the macropores in surface soil decreased by one order of magnitude with 1 KPa increase of soil suction.In the study on the effect of very low soluble salt concentration (EC=0.1 ds m^-1 of irrigation water on soil HC,soil HC was found to be lowered by 30% as a consequence of blocking up of some continuous pores by the dispersed and migrated clay particles.Nonlinear successive regression analysis and significance test show that the effects of EC and SAR of irrigation water on soil HC reached the extremely significant level.展开更多
On the basis of the analysis of coal bed gas pressure in deep mine, and the coal bed permeability ( k ) and the characteristic of adsorption parameter ( b ) changing with temperature, the author puts forward a new cal...On the basis of the analysis of coal bed gas pressure in deep mine, and the coal bed permeability ( k ) and the characteristic of adsorption parameter ( b ) changing with temperature, the author puts forward a new calculating method of gas content in coal seam influenced by in situ stress grads and ground temperature. At the same time, the contrast of the measuring results of coal bed gas pressure with the computing results of coal bed gas pressure and gas content in coal seam in theory indicate that the computing method can well reflect the authenticity of gas content in coal seam,and will further perfect the computing method of gas content in coal seam in theory,and have important value in theory on analyzing gas content in coal seam and forecasting distribution law of gas content in coal seam in deep mine.展开更多
The Absorption and permeability of air-jet textured glass fiber yarn and its fabric and bonded tenacity of the fabric have been studied in relation to the main parameters, air supplied pressure and overfeed ratio.It h...The Absorption and permeability of air-jet textured glass fiber yarn and its fabric and bonded tenacity of the fabric have been studied in relation to the main parameters, air supplied pressure and overfeed ratio.It has been observed that increasing the level of main parameters improves the coated ratio of the textured yarn and its fabric as well as the bonded tenacity of the fabric made of textured yarn. Comparison of absorption or permeability between textured and supplied yarns, and comparison of absorption or permeability and bonded tenacity between the two kinds of fabrics have been elucidated.展开更多
The paper analyses the effect of stitch geometrical modality changing after moisture absorption on the porosity of knitted fabrics,and educes the formulas between porosity and stitch parameters.Regarding as the cell s...The paper analyses the effect of stitch geometrical modality changing after moisture absorption on the porosity of knitted fabrics,and educes the formulas between porosity and stitch parameters.Regarding as the cell stitch,the increasing of yarn diameter brings the porosity decreasing and the fabric shrinking in the wale direction.While the diameter keeps invariability,the yarn elongating brings the fabric humping up as well as the increasing porosity.The air-permeability experiments have been conducted to validate the theoretical analysis,and there is reasonable agreement between the theories and experiments.展开更多
TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by N2 to an APCVD (chemical vapor deposition under atmospheric pressure) reactor at ≤200 ℃. Activated carbon fibers (A...TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by N2 to an APCVD (chemical vapor deposition under atmospheric pressure) reactor at ≤200 ℃. Activated carbon fibers (ACFs) were used as templates for deposition and later removed by calcinations. The obtained catalysts were characterized by scanning electron micros- copy (SEM), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) and X-ray diffraction (XRD) analysis The pores within TiO2 fibers included micro-range and meso-range, e.g., 7 nm, and the specific surface areas for TiO2 fibers were 141 m^2/g and 148 m^2/g for samples deposited at 100 ℃ and 200℃ (using ACFI700 as template), respectively. The deposition temperature significantly influenced TiO2 morphology. The special advantages of this technique for preparing porous nano-material include no consumption of organic solvent in the process and easy control of deposition conditions and speeds.展开更多
The concept of the differential capillary effect was presented by foreign scholars several years ago, and the principle was used to design sportswear fabrics with good wet permeability and good drying functions for fa...The concept of the differential capillary effect was presented by foreign scholars several years ago, and the principle was used to design sportswear fabrics with good wet permeability and good drying functions for famous sports teams. Because the differential capillary effect model was not established in theory,it was impossible to fulfill the best functions. In this paper, by setting up the differential capillary effect of fabric, the factors to influence wet permeability and drying functions of the model is discussed in theory, and the means to optimize the design of the fabric is presented and proven practically by the experiment. The optimum fabric with good permeability and good drying functions can be designed using the model at last.展开更多
Taking low permeability cores of Daqing oilfield for example,the flow characteristics at low velocity were studied with the self-designed micro-flux measuring instrument.Considering the throat distribution and capilla...Taking low permeability cores of Daqing oilfield for example,the flow characteristics at low velocity were studied with the self-designed micro-flux measuring instrument.Considering the throat distribution and capillary model,the thickness of fluid boundary layer under different pressure gradients was calculated,and the mechanism and influencing factors of nonlinear percolation were discussed.The results show that the percolation curve of ultra-low rocks is nonlinear,and apparent permeability is not a constant which increases with pressure gradient.The absorption boundary layer decreases with the increase of pressure gradient,and changes significantly especially in low pressure gradient,which is the essence of nonlinear percolation.The absorption boundary layer is also found to be impacted by the surface property of rocks.展开更多
Using self-developed gas-seepage experimental installation,under the sameeffective stress conditions,coal permeability experiments on different adsorption characteristicsof gases,different temperatures and different g...Using self-developed gas-seepage experimental installation,under the sameeffective stress conditions,coal permeability experiments on different adsorption characteristicsof gases,different temperatures and different gas adsorption contents were performed,and the influence law of adsorption on coal permeability was studied.At the sametime,experimental analogy showed clearly that gas drawing plucks the permeability variationlaw.The results show that adsorption has a major impact on coal permeability.Thegreater the adsorption,the more the gas adsorption capacity and the coal permeabilitybecomes smaller.Permeability becomes smaller along with confining of pressure andtemperature,and this is in accord with local practice results.展开更多
The influence of water vapor on silica membrane with pore size of ,-4A has been investigated in terms of adsorption properties and percolation effect at 50 and 90 ℃. Two methods are employed: spectroscopic ellipsome...The influence of water vapor on silica membrane with pore size of ,-4A has been investigated in terms of adsorption properties and percolation effect at 50 and 90 ℃. Two methods are employed: spectroscopic ellipsometry for water vapor adsorption and gas permeation of binary mixture of helium and H2O The adsorption behaviors on the silica membrane comply with the first-order Langmuir isotherm. The investigation demonstrates that helium flux through the silica membrane decreases dramatically in presence of H20 molecules. The transport of gas molecules through such small pores is believed not to be continuous any more, whereas it is reasonably assumed that the gas molecules hop from one occupied site to another unoccupied one under the potential gradient. When the coverage of H20 molecules on the silica surface increases, the dramatic decrease of helium flux could be related to percolation effect, where the adsorbed H20 molecules on the silica surface block the hopping of helium molecules.展开更多
The biomedical co-continuous(β-TCP+MgO)/Zn-Mg composite was fabricated by infiltrating Zn-Mg alloy into porousβ-TCP+MgO using suction exsorption technique.The microstructure,mechanical properties and corrosion behav...The biomedical co-continuous(β-TCP+MgO)/Zn-Mg composite was fabricated by infiltrating Zn-Mg alloy into porousβ-TCP+MgO using suction exsorption technique.The microstructure,mechanical properties and corrosion behaviors of the composite were evaluated by means of scanning electron microscopy(SEM),X-ray diffraction(XRD),mechanical testing,electrochemical and immersion test.It was found that the molten Zn-Mg alloy had infiltrated not only into the pores but also into the struts of the porousβ-TCP+MgO scaffold to form a compact composite.The Zn-Mg alloy contacted to theβ-TCP+MgO scaffold closely,and no reaction layer can be found between the alloy and the scaffold.The compressive strength of the composite was as high as244MPa,which was about1000times higher than that of the original porousβ-TCP+MgO scaffold and2/3of the strength of the Zn-Mg bulk alloy.The electrochemical and immersion tests in simulated body fluid(SBF)solution indicated that the corrosion resistance of the composite was better than that of the Zn-Mg bulk alloy.The corrosion products on the composite surface were mainly Zn(OH)2.Appropriate mechanical and corrosion properties indicated that the(β-TCP+MgO)/Zn?Mg composite fabricated by suction exsorption would be a very promising candidate for bone substitute.展开更多
文摘The effect of irrigation water quality on unsaturated hydraulic conductivity (HC) of undisturbed soil in field was studied.Results show that within the operating soil suction range (0-1.6 KPa) of disc permeameters,the higher the electric conductivity (EC) of irrigation water,the higher the soil HC became.The soil HC doubled when EC increased from 0.1 to 6.0ds m^-1.High sodium-adsorption ratio(SAR) of irrigation water would have an unfavorable effect on soil HC.Soil HC decreased with the increasing of SAR,especially in the case of higher soil suction.An interaction existed between the effects of EC and SAR of irrigation water on soil HC.The HC of unsaturated soil dependent upon the macropores in surface soil decreased by one order of magnitude with 1 KPa increase of soil suction.In the study on the effect of very low soluble salt concentration (EC=0.1 ds m^-1 of irrigation water on soil HC,soil HC was found to be lowered by 30% as a consequence of blocking up of some continuous pores by the dispersed and migrated clay particles.Nonlinear successive regression analysis and significance test show that the effects of EC and SAR of irrigation water on soil HC reached the extremely significant level.
文摘On the basis of the analysis of coal bed gas pressure in deep mine, and the coal bed permeability ( k ) and the characteristic of adsorption parameter ( b ) changing with temperature, the author puts forward a new calculating method of gas content in coal seam influenced by in situ stress grads and ground temperature. At the same time, the contrast of the measuring results of coal bed gas pressure with the computing results of coal bed gas pressure and gas content in coal seam in theory indicate that the computing method can well reflect the authenticity of gas content in coal seam,and will further perfect the computing method of gas content in coal seam in theory,and have important value in theory on analyzing gas content in coal seam and forecasting distribution law of gas content in coal seam in deep mine.
文摘The Absorption and permeability of air-jet textured glass fiber yarn and its fabric and bonded tenacity of the fabric have been studied in relation to the main parameters, air supplied pressure and overfeed ratio.It has been observed that increasing the level of main parameters improves the coated ratio of the textured yarn and its fabric as well as the bonded tenacity of the fabric made of textured yarn. Comparison of absorption or permeability between textured and supplied yarns, and comparison of absorption or permeability and bonded tenacity between the two kinds of fabrics have been elucidated.
文摘The paper analyses the effect of stitch geometrical modality changing after moisture absorption on the porosity of knitted fabrics,and educes the formulas between porosity and stitch parameters.Regarding as the cell stitch,the increasing of yarn diameter brings the porosity decreasing and the fabric shrinking in the wale direction.While the diameter keeps invariability,the yarn elongating brings the fabric humping up as well as the increasing porosity.The air-permeability experiments have been conducted to validate the theoretical analysis,and there is reasonable agreement between the theories and experiments.
基金Project (No. 20477006) supported by the National Natural ScienceFoundation of China
文摘TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by N2 to an APCVD (chemical vapor deposition under atmospheric pressure) reactor at ≤200 ℃. Activated carbon fibers (ACFs) were used as templates for deposition and later removed by calcinations. The obtained catalysts were characterized by scanning electron micros- copy (SEM), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) and X-ray diffraction (XRD) analysis The pores within TiO2 fibers included micro-range and meso-range, e.g., 7 nm, and the specific surface areas for TiO2 fibers were 141 m^2/g and 148 m^2/g for samples deposited at 100 ℃ and 200℃ (using ACFI700 as template), respectively. The deposition temperature significantly influenced TiO2 morphology. The special advantages of this technique for preparing porous nano-material include no consumption of organic solvent in the process and easy control of deposition conditions and speeds.
文摘The concept of the differential capillary effect was presented by foreign scholars several years ago, and the principle was used to design sportswear fabrics with good wet permeability and good drying functions for famous sports teams. Because the differential capillary effect model was not established in theory,it was impossible to fulfill the best functions. In this paper, by setting up the differential capillary effect of fabric, the factors to influence wet permeability and drying functions of the model is discussed in theory, and the means to optimize the design of the fabric is presented and proven practically by the experiment. The optimum fabric with good permeability and good drying functions can be designed using the model at last.
基金Project(2008ZX05013) supported by the National Science and Technology Project of ChinaProject(10672187) supported by the National Natural Science Foundation of China
文摘Taking low permeability cores of Daqing oilfield for example,the flow characteristics at low velocity were studied with the self-designed micro-flux measuring instrument.Considering the throat distribution and capillary model,the thickness of fluid boundary layer under different pressure gradients was calculated,and the mechanism and influencing factors of nonlinear percolation were discussed.The results show that the percolation curve of ultra-low rocks is nonlinear,and apparent permeability is not a constant which increases with pressure gradient.The absorption boundary layer decreases with the increase of pressure gradient,and changes significantly especially in low pressure gradient,which is the essence of nonlinear percolation.The absorption boundary layer is also found to be impacted by the surface property of rocks.
文摘Using self-developed gas-seepage experimental installation,under the sameeffective stress conditions,coal permeability experiments on different adsorption characteristicsof gases,different temperatures and different gas adsorption contents were performed,and the influence law of adsorption on coal permeability was studied.At the sametime,experimental analogy showed clearly that gas drawing plucks the permeability variationlaw.The results show that adsorption has a major impact on coal permeability.Thegreater the adsorption,the more the gas adsorption capacity and the coal permeabilitybecomes smaller.Permeability becomes smaller along with confining of pressure andtemperature,and this is in accord with local practice results.
基金This work was supported by the Fhndamental Research Funds for the Central Universities (No.XDJK2015C002) and the National Natural Science Foundation of China (No.51402243). Special thanks are given to Prof. H. J. M Bouwmeester and Dr. N.E. Benes from University of Twente for fruitful discussion.
文摘The influence of water vapor on silica membrane with pore size of ,-4A has been investigated in terms of adsorption properties and percolation effect at 50 and 90 ℃. Two methods are employed: spectroscopic ellipsometry for water vapor adsorption and gas permeation of binary mixture of helium and H2O The adsorption behaviors on the silica membrane comply with the first-order Langmuir isotherm. The investigation demonstrates that helium flux through the silica membrane decreases dramatically in presence of H20 molecules. The transport of gas molecules through such small pores is believed not to be continuous any more, whereas it is reasonably assumed that the gas molecules hop from one occupied site to another unoccupied one under the potential gradient. When the coverage of H20 molecules on the silica surface increases, the dramatic decrease of helium flux could be related to percolation effect, where the adsorbed H20 molecules on the silica surface block the hopping of helium molecules.
基金Project (51101039) supported by the National Natural Science Foundation of ChinaProject (E201005) supported by the Natural Science Foundation of Heilongjiang Province,China
文摘The biomedical co-continuous(β-TCP+MgO)/Zn-Mg composite was fabricated by infiltrating Zn-Mg alloy into porousβ-TCP+MgO using suction exsorption technique.The microstructure,mechanical properties and corrosion behaviors of the composite were evaluated by means of scanning electron microscopy(SEM),X-ray diffraction(XRD),mechanical testing,electrochemical and immersion test.It was found that the molten Zn-Mg alloy had infiltrated not only into the pores but also into the struts of the porousβ-TCP+MgO scaffold to form a compact composite.The Zn-Mg alloy contacted to theβ-TCP+MgO scaffold closely,and no reaction layer can be found between the alloy and the scaffold.The compressive strength of the composite was as high as244MPa,which was about1000times higher than that of the original porousβ-TCP+MgO scaffold and2/3of the strength of the Zn-Mg bulk alloy.The electrochemical and immersion tests in simulated body fluid(SBF)solution indicated that the corrosion resistance of the composite was better than that of the Zn-Mg bulk alloy.The corrosion products on the composite surface were mainly Zn(OH)2.Appropriate mechanical and corrosion properties indicated that the(β-TCP+MgO)/Zn?Mg composite fabricated by suction exsorption would be a very promising candidate for bone substitute.