Surface active ionic liquids (SAILs) are considered as prominent materials in enhanced oil recovery thanks to their high interfacial activity. This study reports the preparation and applications of a nanostructure Tri...Surface active ionic liquids (SAILs) are considered as prominent materials in enhanced oil recovery thanks to their high interfacial activity. This study reports the preparation and applications of a nanostructure Tripodal imidazolium SAIL as an environmentally-friendly substitute to the conventional surfactants. The product has a star-like molecular structure centered by a triazine spacer, namely [(C_(4)im)_(3)TA][Cl_(3)], prepared by a one-step synthesis method and characterized with FT-IR, NMR, XRD, and SEM analysis methods. The interfacial tension of the system was decreased to about 78% at critical micelle concentration of less than 0.08 mol·dm^(−3). Increasing temperature, from 298.2 to 323.2 K, improved this capability. The solid surface wettability was changed from oil-wet to water-wet and 80% and 77% stable emulsions of crude oil–aqueous solutions were created after one day and one week, respectively. Compared to the Gemini kind homologous SAILs, the superior effects of the Tripodal SAIL were revealed and attributed to the strong hydrophobic branches in the molecule. The Frumkin adsorption isotherm precisely reproduced the generated IFT data, and accordingly, the adsorption and thermodynamic parameters were determined.展开更多
临床预测模型开发和验证过程的完整报告对于模型外部验证及临床应用至关重要。《个体预后或诊断的多变量预测模型透明报告》(Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis,TRIPOD...临床预测模型开发和验证过程的完整报告对于模型外部验证及临床应用至关重要。《个体预后或诊断的多变量预测模型透明报告》(Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis,TRIPOD)为规范化预测模型的报告过程及报告质量评价提供了指导。本文将采用例解的形式对TRIPOD报告规范各条目进行详细解读,便于临床预测模型领域的研究者更好地掌握及应用该报告规范,进而提高预测模型的报告质量。展开更多
临床预测模型开发和验证过程的完整报告对于模型外部验证及临床应用至关重要。《个体预后或诊断的多变量预测模型透明报告》(Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis,TRIPOD...临床预测模型开发和验证过程的完整报告对于模型外部验证及临床应用至关重要。《个体预后或诊断的多变量预测模型透明报告》(Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis,TRIPOD)为规范化预测模型的报告过程及报告质量评价提供了指导。本文将采用例解的形式对TRIPOD报告规范各条目进行详细解读,便于临床预测模型领域的研究者更好地掌握及应用该报告规范,进而提高预测模型的报告质量。展开更多
Fixed offshore wind turbines usually have large underwater supporting structures. The fluid influences the dynamic characteristics of the structure system. The dynamic model of a 5-MW tripod offshore wind turbine cons...Fixed offshore wind turbines usually have large underwater supporting structures. The fluid influences the dynamic characteristics of the structure system. The dynamic model of a 5-MW tripod offshore wind turbine considering the pile-soil system and fluid structure interaction （FSI） is established, and the structural modes in air and in water are obtained by use of ANSYS. By comparing low-order natural frequencies and mode shapes, the influence of sea water on the free vibration characteristics of offshore wind turbine is analyzed. On basis of the above work, seismic responses under excitation by E1-Centro waves are calculated by the time-history analysis method. The results reveal that the dynamic responses such as the lateral displacement of the foundation and the section bending moment of the tubular piles increase substantially under the influence of the added-mass and hydrodynamic pressure of sea water. The method and conclusions presented in this paper can provide a theoretical reference for structure design and analysis of offshore wind turbines fixed in deep seawater.展开更多
The electrically driven six-legged robot with high carrying capacity is an indispensable equipment for planetary exploration, but it hinders its practicability because of its low efficiency of carrying energy. Meanwhi...The electrically driven six-legged robot with high carrying capacity is an indispensable equipment for planetary exploration, but it hinders its practicability because of its low efficiency of carrying energy. Meanwhile, its load capacity also affects its application range. To reduce the power consumption, increase the load to mass ratio, and improve the stability of robot, the relationship between the walking modes and the forces of feet under the tripod gait are researched for an electrically driven heavy-duty six-legged robot. Based on the configuration characteristics of electrically driven heavy-duty six-legged, the typical walking modes of robot are analyzed. The mathematical models of the normal forces of feet are respectively established under the tripod gait of typical walking modes. According to the MATLAB software, the variable tendency charts are respectively gained for the normal forces of feet. The walking experiments under the typical tripod gaits are implemented for the prototype of electrically driven heavy-duty six-legged robot. The variable tendencies of maximum normal forces of feet are acquired. The comparison results show that the theoretical and experimental data are in the same trend. The walking modes which are most available to realize the average force of distribution of each foot are confirmed. The proposed method of analyzing the relationship between the walking modes and the forces of feet can quickly determine the optimal walking mode and gait parameters under the average distribution of foot force, which is propitious to develop the excellent heavy-duty multi-legged robots with the lower power consumption, larger load to mass ratio, and higher stability.展开更多
基金The authors would like to acknowledge the Bu Ali Sina University and the Iran National Science Foundation:INSF,under Grant number of 99031559,for their financial supports.
文摘Surface active ionic liquids (SAILs) are considered as prominent materials in enhanced oil recovery thanks to their high interfacial activity. This study reports the preparation and applications of a nanostructure Tripodal imidazolium SAIL as an environmentally-friendly substitute to the conventional surfactants. The product has a star-like molecular structure centered by a triazine spacer, namely [(C_(4)im)_(3)TA][Cl_(3)], prepared by a one-step synthesis method and characterized with FT-IR, NMR, XRD, and SEM analysis methods. The interfacial tension of the system was decreased to about 78% at critical micelle concentration of less than 0.08 mol·dm^(−3). Increasing temperature, from 298.2 to 323.2 K, improved this capability. The solid surface wettability was changed from oil-wet to water-wet and 80% and 77% stable emulsions of crude oil–aqueous solutions were created after one day and one week, respectively. Compared to the Gemini kind homologous SAILs, the superior effects of the Tripodal SAIL were revealed and attributed to the strong hydrophobic branches in the molecule. The Frumkin adsorption isotherm precisely reproduced the generated IFT data, and accordingly, the adsorption and thermodynamic parameters were determined.
文摘临床预测模型开发和验证过程的完整报告对于模型外部验证及临床应用至关重要。《个体预后或诊断的多变量预测模型透明报告》(Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis,TRIPOD)为规范化预测模型的报告过程及报告质量评价提供了指导。本文将采用例解的形式对TRIPOD报告规范各条目进行详细解读,便于临床预测模型领域的研究者更好地掌握及应用该报告规范,进而提高预测模型的报告质量。
基金The National Natural Science Foundation of China(Nos.21203050,61307056,11274210,11374084)the Anhui Provincial Natural Science Foundation(No.1508085QF123)
文摘临床预测模型开发和验证过程的完整报告对于模型外部验证及临床应用至关重要。《个体预后或诊断的多变量预测模型透明报告》(Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis,TRIPOD)为规范化预测模型的报告过程及报告质量评价提供了指导。本文将采用例解的形式对TRIPOD报告规范各条目进行详细解读,便于临床预测模型领域的研究者更好地掌握及应用该报告规范,进而提高预测模型的报告质量。
基金financially supported by the Fund for Creative Research Groups of China(Grant No.51421064)
文摘Fixed offshore wind turbines usually have large underwater supporting structures. The fluid influences the dynamic characteristics of the structure system. The dynamic model of a 5-MW tripod offshore wind turbine considering the pile-soil system and fluid structure interaction （FSI） is established, and the structural modes in air and in water are obtained by use of ANSYS. By comparing low-order natural frequencies and mode shapes, the influence of sea water on the free vibration characteristics of offshore wind turbine is analyzed. On basis of the above work, seismic responses under excitation by E1-Centro waves are calculated by the time-history analysis method. The results reveal that the dynamic responses such as the lateral displacement of the foundation and the section bending moment of the tubular piles increase substantially under the influence of the added-mass and hydrodynamic pressure of sea water. The method and conclusions presented in this paper can provide a theoretical reference for structure design and analysis of offshore wind turbines fixed in deep seawater.
基金Supported by National Natural Science Foundation of China(Grant Nos.51505335,51275106)National Basic Research Program of China(973Program,Grant No.2013CB035502)
文摘The electrically driven six-legged robot with high carrying capacity is an indispensable equipment for planetary exploration, but it hinders its practicability because of its low efficiency of carrying energy. Meanwhile, its load capacity also affects its application range. To reduce the power consumption, increase the load to mass ratio, and improve the stability of robot, the relationship between the walking modes and the forces of feet under the tripod gait are researched for an electrically driven heavy-duty six-legged robot. Based on the configuration characteristics of electrically driven heavy-duty six-legged, the typical walking modes of robot are analyzed. The mathematical models of the normal forces of feet are respectively established under the tripod gait of typical walking modes. According to the MATLAB software, the variable tendency charts are respectively gained for the normal forces of feet. The walking experiments under the typical tripod gaits are implemented for the prototype of electrically driven heavy-duty six-legged robot. The variable tendencies of maximum normal forces of feet are acquired. The comparison results show that the theoretical and experimental data are in the same trend. The walking modes which are most available to realize the average force of distribution of each foot are confirmed. The proposed method of analyzing the relationship between the walking modes and the forces of feet can quickly determine the optimal walking mode and gait parameters under the average distribution of foot force, which is propitious to develop the excellent heavy-duty multi-legged robots with the lower power consumption, larger load to mass ratio, and higher stability.
