The design of a pressurized capillary rheometer operating at prescribed temperature is described to measure the viscosity of magnetic fluids （MFs） containing Fe3O4 magnetic nanoparticles （MNPs）. The equipment cons...The design of a pressurized capillary rheometer operating at prescribed temperature is described to measure the viscosity of magnetic fluids （MFs） containing Fe3O4 magnetic nanoparticles （MNPs）. The equipment constant of the rheometer was obtained using liquids with predetermined viscosities. Experimentally measured viscosities were used to evaluate different equations for suspension viscosities. Deviation of measured suspension viscosities from the Einstein equation was found to be basically due to the influence of spatial distribution and aggregation of Fe3O4 MNPs. By taking account of the coating layer on MNPs and the aggregation of MNPs in MFs, a modified Einstein equation was proposed to fit the experimental data. Moreover, the influence of external magnetic field on viscosity was also taken into account. Viscosities thus predicted are in good agreement with experimental data. Temperature effect on suspension viscosity was shown experimentally to be due to the shear-thinning behavior of the MFs.展开更多
An experimental study was carried out to investigate the amount of drugs loaded on microneedles. The microneedles were made with poly (lactic acid). Aqueous poly (vinyl alcohol) solutions were prepared as drug solutio...An experimental study was carried out to investigate the amount of drugs loaded on microneedles. The microneedles were made with poly (lactic acid). Aqueous poly (vinyl alcohol) solutions were prepared as drug solutions. Two drug loading approaches, i.e., dropping and dipping, were examined. It was found that capillary number is the only relevant dimensionless group for the two methods. For the dropping approach, dried drugs will spread near the bottom of a microneedle patch provided the surface tension is low. As for the dipping approach, both a single microneedle and an array of nine microneedles were examined. For a single microneedle, high capillary rises before pulling and pulling speed are two key factors to increase the drug loading volume. For an array of microneedles, the effect of capillary rise owing to the interaction between microneedles would increase the drug loading volume several times higher than a single microneedle of the same dimension.展开更多
Deformation of the spherical capsule in 3D simple shear fow is simulated using the immersed boundary method. The capsule membrane is regarded as an elastic medium satisfying the Neo-Hookean or Skalak elasticity. The m...Deformation of the spherical capsule in 3D simple shear fow is simulated using the immersed boundary method. The capsule membrane is regarded as an elastic medium satisfying the Neo-Hookean or Skalak elasticity. The motions of the capsule under various capillary numbers are studied. The results show that the deformation of the capsule becomes larger as the capillary number increases;in the same shear fow,the deformation under Skalak law is smaller than that under Neo-Hookean;for small capillary number the Taylor parameter agrees well with the analytical solution,whereas for large capillary number it is less than the analytical solution. Those results are validated by previous works obtained by the boundary integral method and the immersed boundary method.展开更多
Retrograde condensation frequently occurs during the development of gas condensate reservoirs. The loss of productivity is often observed due to the reduced relative permeability to gas as condensate accumulates ne...Retrograde condensation frequently occurs during the development of gas condensate reservoirs. The loss of productivity is often observed due to the reduced relative permeability to gas as condensate accumulates near the well bore region. How to describe the condensate blockage effect exactly has been a continuous research topic. However, up to now, the present methods usually over-estimate or underestimate the productivity reduction due to an incorrect understanding of the mechanism of flow in porous medium, which inevitably results in an inaccurate prediction of production performance. It has been found in recent numerous theoretical and experimental studies that capillary number and non-Darcy flow have significant influence on relative permeability in regions near the well bore. The two effects impose opposite impacts on production performance, thus leading to gas condensate flow showing characteristics different from general understanding. It is significant for prediction of performance in gas condensate wells to understand the two effects exactly. The aim of the paper is to describe and analyze the flow dynamics in porous media accurately during the production of gas condensate reservoirs. Based on the description of three-zone flow mechanism, capillary number and non-Darcy effect are incorporated in the analysis of relative permeability, making it possible to describe the effect of condensate blockage. The effect of capillary number and inertial flow on gas and condensate relative permeability is analyzed in detail. Novel Inflow Performance Relation (IPR) models considering high velocity effects are formulated and the contrast analysis of different IPR models is conducted. The result shows that the proposed method can help predict the production performance and productivity more accurately than conventional methods.展开更多
The steady laminar pipe flow of a suspension with a gas volume fraction ∅≤0.5 and small or intermediate bubble deformations in long, and straight sections of a circular pipe is calculated. The calcula...The steady laminar pipe flow of a suspension with a gas volume fraction ∅≤0.5 and small or intermediate bubble deformations in long, and straight sections of a circular pipe is calculated. The calculations are based on the constitutive equation that was originally derived for dilute emulsions and further developed for concentrated suspensions containing bubbles. In contrast to the literature, an analytical procedure is used to determine the solution of a pipe flow more accurately. The results are presented and discussed with respect to the Reynolds number Re and capillary number Ca. If Ca 1, a bubble suspension has a parabolic velocity profile indicating a Newtonian rheology. If Ca ≈1, two regimes of flow are observed in agreement with the literature;that is, an inner plug flow where deformation rates are low and an outer flow where deformation rates are high. These results imply that, if Ca ∅?and that, if Ca ≥1, the opposite effect occurs;that is, the Reynolds number Re increases with increasing gas volume fraction.展开更多
To better understand the multiphase fluid dynamics and associated transport processes of cavitating flows at the capillary number of 0.74 and 0.54, and to validate the numerical results, a combined computational and e...To better understand the multiphase fluid dynamics and associated transport processes of cavitating flows at the capillary number of 0.74 and 0.54, and to validate the numerical results, a combined computational and experimental investigation of flows around a hydrofoil is studied based on flow visualizations and time-resolved interface movement. The computational model is based on a modified RNG k-ε model as turbulence closure, along with a vapor-liquid mass transfer model for treating the cavitation process. Overall, favorable agreement between the numerical and experimental results is observed. It is shown that the cavi- tation structure depends on the interaction of the water-vapor mixture and the vapor among the whole cavitation stage, the interface between the vapor and the two-phase mixture exhibits substantial unsteadiness. And, the adverse motion of the interface relates to pressure and velocity fluctuations inside the cavity. In particular, the velocity in the vapor region is lower than that in the two-phase region.展开更多
Objective:To observe the effects of the external application of Qiyu oil(芪榆油)gauze(QYOG) for promoting post-operational healing in patients with anal fistula and to explore its mechanism of action so as to provide ...Objective:To observe the effects of the external application of Qiyu oil(芪榆油)gauze(QYOG) for promoting post-operational healing in patients with anal fistula and to explore its mechanism of action so as to provide a beneficial scientific basis for its wide use.Methods:Sixty patients with anal fistula scheduled to receive simple low anal fistulectomy were equally assigned,according to the sequence of hospitalization, to the tested group and the control group,and their wounds were classified according to long...展开更多
With the development of the Tazhong No. 1 carbonate gas condensate reservoir in China, it has become more and more important to study the characteristics of gas condensate well deliverability. A single-well radial sim...With the development of the Tazhong No. 1 carbonate gas condensate reservoir in China, it has become more and more important to study the characteristics of gas condensate well deliverability. A single-well radial simulator for dual-permeability reservoirs was established to study the influences of fluid properties, permeability, and pressure drawdown on well deliverability with and without the capillary number effect. The simulation shows that well deliverability basically maintains its initial value and is not affected by the capillary number when the formation pressure is higher than dew-point pressure. However, well deliverability drops rapidly when the formation pressure is lower than dew-point pressure. Even if the condensate dropout is very low, well deliverability without the capillary number effect reduces to 50 percent of its initial value when reservoir pressure declines to 95 percent of dew-point pressure, but well deliverability is significantly improved if the capillary number effect exists. The capillary number effect is most significant when reservoir pressure is just lower than dew point pressure, then the effect decreases; the reduction of well deliverability is mainly caused by the reduction of gas relative permeability of the matrix system near the wellbore.展开更多
目的建立针对食品来源的单核细胞增生李斯特氏菌(Listeria monocytogenes,Lm)分离株的多位点串联重复序列分型(Multiple-Locus Variable number tandem repeat Analysis,MLVA)方法,为暴发确认和溯源检测提供实验室支持。方法对2005—201...目的建立针对食品来源的单核细胞增生李斯特氏菌(Listeria monocytogenes,Lm)分离株的多位点串联重复序列分型(Multiple-Locus Variable number tandem repeat Analysis,MLVA)方法,为暴发确认和溯源检测提供实验室支持。方法对2005—2014年间分离自食品的91株Lm进行14个可变数目串联重复序列(Variable Number of Tandem Repeats,VNTR)位点的检测,评估最优检测位点组合并分析检测结果。结果通过采用软件分析,由LMV1、LMV2、LMV7、Lm10、Lm11、Lm23、LM-TR6、TR3和Lm15等9个VNTR位点组成的位点组合为最优MLVA检测位点,可以将91株Lm分离株分为70个型别,分型能力达到0.987 1。结论本研究建立的基于全自动毛细管电泳的由9个检测位点组成的Lm的MLVA分型方法,具有操作简便、快速、结果客观、操作标准化、易于在不同实验室间比较的优势,可作为一线检测方法用于李斯特菌病的暴发确认和溯源检测。展开更多
基金supported by the National Natural Science Foundation of China(NNSFC,Nos.20476065 and 20736004)the Scientific Research Foundation for the Returned Overseas Chinese Scholars of State Education Ministry,the State Key Laboratory of Multiphase Reaction of the Chinese Academy of Science(No.2003-5)the Key Laboratory of Organic Synthesis of Jiangsu Province,the Chemical Experiment Center of Soochow University and R&D Foundation of Nanjing Medical University(NY0586).
文摘The design of a pressurized capillary rheometer operating at prescribed temperature is described to measure the viscosity of magnetic fluids （MFs） containing Fe3O4 magnetic nanoparticles （MNPs）. The equipment constant of the rheometer was obtained using liquids with predetermined viscosities. Experimentally measured viscosities were used to evaluate different equations for suspension viscosities. Deviation of measured suspension viscosities from the Einstein equation was found to be basically due to the influence of spatial distribution and aggregation of Fe3O4 MNPs. By taking account of the coating layer on MNPs and the aggregation of MNPs in MFs, a modified Einstein equation was proposed to fit the experimental data. Moreover, the influence of external magnetic field on viscosity was also taken into account. Viscosities thus predicted are in good agreement with experimental data. Temperature effect on suspension viscosity was shown experimentally to be due to the shear-thinning behavior of the MFs.
文摘An experimental study was carried out to investigate the amount of drugs loaded on microneedles. The microneedles were made with poly (lactic acid). Aqueous poly (vinyl alcohol) solutions were prepared as drug solutions. Two drug loading approaches, i.e., dropping and dipping, were examined. It was found that capillary number is the only relevant dimensionless group for the two methods. For the dropping approach, dried drugs will spread near the bottom of a microneedle patch provided the surface tension is low. As for the dipping approach, both a single microneedle and an array of nine microneedles were examined. For a single microneedle, high capillary rises before pulling and pulling speed are two key factors to increase the drug loading volume. For an array of microneedles, the effect of capillary rise owing to the interaction between microneedles would increase the drug loading volume several times higher than a single microneedle of the same dimension.
基金the National Natural Science Foundation of China (No. 10472070)the Shanghai Leading Academic Discipline Project (No. B206)
文摘Deformation of the spherical capsule in 3D simple shear fow is simulated using the immersed boundary method. The capsule membrane is regarded as an elastic medium satisfying the Neo-Hookean or Skalak elasticity. The motions of the capsule under various capillary numbers are studied. The results show that the deformation of the capsule becomes larger as the capillary number increases;in the same shear fow,the deformation under Skalak law is smaller than that under Neo-Hookean;for small capillary number the Taylor parameter agrees well with the analytical solution,whereas for large capillary number it is less than the analytical solution. Those results are validated by previous works obtained by the boundary integral method and the immersed boundary method.
基金Project“973",a national fundamental research development program
文摘Retrograde condensation frequently occurs during the development of gas condensate reservoirs. The loss of productivity is often observed due to the reduced relative permeability to gas as condensate accumulates near the well bore region. How to describe the condensate blockage effect exactly has been a continuous research topic. However, up to now, the present methods usually over-estimate or underestimate the productivity reduction due to an incorrect understanding of the mechanism of flow in porous medium, which inevitably results in an inaccurate prediction of production performance. It has been found in recent numerous theoretical and experimental studies that capillary number and non-Darcy flow have significant influence on relative permeability in regions near the well bore. The two effects impose opposite impacts on production performance, thus leading to gas condensate flow showing characteristics different from general understanding. It is significant for prediction of performance in gas condensate wells to understand the two effects exactly. The aim of the paper is to describe and analyze the flow dynamics in porous media accurately during the production of gas condensate reservoirs. Based on the description of three-zone flow mechanism, capillary number and non-Darcy effect are incorporated in the analysis of relative permeability, making it possible to describe the effect of condensate blockage. The effect of capillary number and inertial flow on gas and condensate relative permeability is analyzed in detail. Novel Inflow Performance Relation (IPR) models considering high velocity effects are formulated and the contrast analysis of different IPR models is conducted. The result shows that the proposed method can help predict the production performance and productivity more accurately than conventional methods.
文摘The steady laminar pipe flow of a suspension with a gas volume fraction ∅≤0.5 and small or intermediate bubble deformations in long, and straight sections of a circular pipe is calculated. The calculations are based on the constitutive equation that was originally derived for dilute emulsions and further developed for concentrated suspensions containing bubbles. In contrast to the literature, an analytical procedure is used to determine the solution of a pipe flow more accurately. The results are presented and discussed with respect to the Reynolds number Re and capillary number Ca. If Ca 1, a bubble suspension has a parabolic velocity profile indicating a Newtonian rheology. If Ca ≈1, two regimes of flow are observed in agreement with the literature;that is, an inner plug flow where deformation rates are low and an outer flow where deformation rates are high. These results imply that, if Ca ∅?and that, if Ca ≥1, the opposite effect occurs;that is, the Reynolds number Re increases with increasing gas volume fraction.
基金supported by the National Natural Science Foundation of China (50679001)NASA Constellation University Institutes Program
文摘To better understand the multiphase fluid dynamics and associated transport processes of cavitating flows at the capillary number of 0.74 and 0.54, and to validate the numerical results, a combined computational and experimental investigation of flows around a hydrofoil is studied based on flow visualizations and time-resolved interface movement. The computational model is based on a modified RNG k-ε model as turbulence closure, along with a vapor-liquid mass transfer model for treating the cavitation process. Overall, favorable agreement between the numerical and experimental results is observed. It is shown that the cavi- tation structure depends on the interaction of the water-vapor mixture and the vapor among the whole cavitation stage, the interface between the vapor and the two-phase mixture exhibits substantial unsteadiness. And, the adverse motion of the interface relates to pressure and velocity fluctuations inside the cavity. In particular, the velocity in the vapor region is lower than that in the two-phase region.
基金Supported by the Funds of Guiyang College of Traditional Chinese Medicine(No.200607)
文摘Objective:To observe the effects of the external application of Qiyu oil(芪榆油)gauze(QYOG) for promoting post-operational healing in patients with anal fistula and to explore its mechanism of action so as to provide a beneficial scientific basis for its wide use.Methods:Sixty patients with anal fistula scheduled to receive simple low anal fistulectomy were equally assigned,according to the sequence of hospitalization, to the tested group and the control group,and their wounds were classified according to long...
基金Project "973",a national fundamental research development program,for its financial support
文摘With the development of the Tazhong No. 1 carbonate gas condensate reservoir in China, it has become more and more important to study the characteristics of gas condensate well deliverability. A single-well radial simulator for dual-permeability reservoirs was established to study the influences of fluid properties, permeability, and pressure drawdown on well deliverability with and without the capillary number effect. The simulation shows that well deliverability basically maintains its initial value and is not affected by the capillary number when the formation pressure is higher than dew-point pressure. However, well deliverability drops rapidly when the formation pressure is lower than dew-point pressure. Even if the condensate dropout is very low, well deliverability without the capillary number effect reduces to 50 percent of its initial value when reservoir pressure declines to 95 percent of dew-point pressure, but well deliverability is significantly improved if the capillary number effect exists. The capillary number effect is most significant when reservoir pressure is just lower than dew point pressure, then the effect decreases; the reduction of well deliverability is mainly caused by the reduction of gas relative permeability of the matrix system near the wellbore.
文摘目的建立针对食品来源的单核细胞增生李斯特氏菌(Listeria monocytogenes,Lm)分离株的多位点串联重复序列分型(Multiple-Locus Variable number tandem repeat Analysis,MLVA)方法,为暴发确认和溯源检测提供实验室支持。方法对2005—2014年间分离自食品的91株Lm进行14个可变数目串联重复序列(Variable Number of Tandem Repeats,VNTR)位点的检测,评估最优检测位点组合并分析检测结果。结果通过采用软件分析,由LMV1、LMV2、LMV7、Lm10、Lm11、Lm23、LM-TR6、TR3和Lm15等9个VNTR位点组成的位点组合为最优MLVA检测位点,可以将91株Lm分离株分为70个型别,分型能力达到0.987 1。结论本研究建立的基于全自动毛细管电泳的由9个检测位点组成的Lm的MLVA分型方法,具有操作简便、快速、结果客观、操作标准化、易于在不同实验室间比较的优势,可作为一线检测方法用于李斯特菌病的暴发确认和溯源检测。
