A number of investigations into application of polymers for macro-morphological modification of tool surface have been carried out. These researches, with extensive stress on convex or domed protuberations as one of t...A number of investigations into application of polymers for macro-morphological modification of tool surface have been carried out. These researches, with extensive stress on convex or domed protuberations as one of the widely used construction units, have tried to harness benefits from using polymers in agriculture. Ultra high molecular weight polyethylene （UHMW-PE） has proved an emerging polymer in its application to reduce soil adhesion. This research was conducted to study the effect of shape （flat, semi-spherical, semi-oblate, semi short-prolate and semi long-prolate） and dimensions （base diameter and dome height） on sliding resistance and normal adhesion of biomimetic plates. To incorporate both shape and size, a dimensionless ratio of height to diameter （HDR） was introduced to characterize the effect of construction unit＇s physique. Experiments were conducted in Bangkok clay soil with dry （ 19.8% d.b.）, sticky （36.9% d.b.） and flooded （60.1% d.b.） soil conditions respectively. Soil at sticky limit exhibited the highest sliding resistance （77.8 N） and normal adhesion （3 kPa to 7 kPa）, whereas these values were 61.7 N and 〈0.2 kPa in dry, and 53.7 N and 0.5 kPa to 1.5 kPa in flooded soil conditions. Protuberances with HDR ≤ 0.5 lowered sliding resistance by 10% - 30% and the same reduced normal adhesion by 10% - 60%. The amount of reduction in both sliding resistance and normal adhesion was higher in flooded soil. Lighter normal loads obviously produced lesser resistance and adhesion.展开更多
Due to complicated working conditions,the normal operating large-scale wind turbine blades are often suffering from some inevitable problems,i.e.,friction adhesion,flow separation and acoustic noise,which may signific...Due to complicated working conditions,the normal operating large-scale wind turbine blades are often suffering from some inevitable problems,i.e.,friction adhesion,flow separation and acoustic noise,which may significantly affect the aerodynamic performance of the blades and thus the wind turbine system.Therefore,effective measurements must be taken to solve these issues.Correspondingly,several novel bionic flow control methods by mimicking shark skin,whale fin and owl wing,i.e.,riblet,leading-edge protuberance and trailing-edge serration,have been recently studied,and good progresses have been made in terms of effectiveness,analysis and mechanism.However,these potential techniques are unable to be widely applied within wind energy community due to the lack of reasonable modeling methods,clearly reflecting the effect of bionic structures on the flow field around,which results in incapability to carry out further optimal design of bionic blade.To this end,this review paper first concentrated on a summary of the control mechanisms of three bionic techniques.Based on this,some feasible ideas of model buildup were proposed.Finally,the flow analyses around the typical blade airfoils were chosen as case studies to verify the feasibility and accuracy of these simulation methods.展开更多
This study explored the clinical value of endoscopic ligation for the treatment of upper gastrointestinal(GI)protuberant lesions in children.According to the appearance and size of lesions,we used different ligation t...This study explored the clinical value of endoscopic ligation for the treatment of upper gastrointestinal(GI)protuberant lesions in children.According to the appearance and size of lesions,we used different ligation techniques for the treatment of the lesions.Endoscopic ultrasonography was used for preliminary characterization of the lesions.One case diagnosed with PeutzJeghers syndrome was successfully treated by a detachable snare.Two cases with semi-pedunculated or broad-base lesions originating from the submucosal layer of the upper GI were treated with endoscopic variceal ligation;endoscopic examination showed that one case had complete healing 11 wk after ligation,while an ulcer scar was observed at the ligation site after 6 wk in the other case.All lesions were successfully ligated at the first attempt.No significant complications occurred either during or after the procedure.Selective endoscopic ligation of upper GI lesions is an effective and safe treatment for upper GI protuberant lesions in children.展开更多
The influence of the three-way interaction between the fungus (Curvularia protuberata), virus (CThTV), and tomato (Solanum lycopersicum) in combating drought stress was evaluated in this study. The plants in this gree...The influence of the three-way interaction between the fungus (Curvularia protuberata), virus (CThTV), and tomato (Solanum lycopersicum) in combating drought stress was evaluated in this study. The plants in this greenhouse experiment were grown under conditions of 400 ± 150 μmol·m-2·s-1 photon flux density, 45% to 50% relative humidity (RH), and 30°C ± 2°C. Tomato seeds were germinated and inoculated with the combination of the fungus and virus at the seedling stage. The plants were allowed to grow for two weeks and randomly selected individuals were utilized. The selected plants were grown in one gallon pots containing organic potting soil. The treatments included non-symbiotic (NS), virus-free (VF), and symbiotic (An) plants. Each treatment received twelve samples and each sample was allowed to grow for an additional two weeks under drought stress. At that time, plants were exhibiting drought stress symptoms including visible wilting. Six samples from each treatment were utilized in determining selected physiological responses of tomato at pre-anthesis stage. The remaining six samples from each treatment were re-watered once and allowed to grow until they reached the anthesis stage. When they showed visible signs of wilting, the same physiological responses measured during pre-anthesis were conducted. The samples of each treatment were utilized at the end of each stage in determining photosynthetic rate, stomata conductance, photosynthetic pigments, water potential, and soluble sugar content. Plant growth, chlorophyll a, chlorophyll b, photosynthetic rate, stomata conductance, water potential, and soluble sugar content were similarly affected by the various treatments. However, carotenoids were significantly higher at pre-anthesis in the symbiotic plants in comparison to other treatments. Additionally, photosynthesis appeared to be significantly higher at anthesis compared to pre-anthesis for all treatments.展开更多
文摘A number of investigations into application of polymers for macro-morphological modification of tool surface have been carried out. These researches, with extensive stress on convex or domed protuberations as one of the widely used construction units, have tried to harness benefits from using polymers in agriculture. Ultra high molecular weight polyethylene （UHMW-PE） has proved an emerging polymer in its application to reduce soil adhesion. This research was conducted to study the effect of shape （flat, semi-spherical, semi-oblate, semi short-prolate and semi long-prolate） and dimensions （base diameter and dome height） on sliding resistance and normal adhesion of biomimetic plates. To incorporate both shape and size, a dimensionless ratio of height to diameter （HDR） was introduced to characterize the effect of construction unit＇s physique. Experiments were conducted in Bangkok clay soil with dry （ 19.8% d.b.）, sticky （36.9% d.b.） and flooded （60.1% d.b.） soil conditions respectively. Soil at sticky limit exhibited the highest sliding resistance （77.8 N） and normal adhesion （3 kPa to 7 kPa）, whereas these values were 61.7 N and 〈0.2 kPa in dry, and 53.7 N and 0.5 kPa to 1.5 kPa in flooded soil conditions. Protuberances with HDR ≤ 0.5 lowered sliding resistance by 10% - 30% and the same reduced normal adhesion by 10% - 60%. The amount of reduction in both sliding resistance and normal adhesion was higher in flooded soil. Lighter normal loads obviously produced lesser resistance and adhesion.
基金supported by the National Natural Science Foundation of China(Grant No.51736008)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21050303)。
文摘Due to complicated working conditions,the normal operating large-scale wind turbine blades are often suffering from some inevitable problems,i.e.,friction adhesion,flow separation and acoustic noise,which may significantly affect the aerodynamic performance of the blades and thus the wind turbine system.Therefore,effective measurements must be taken to solve these issues.Correspondingly,several novel bionic flow control methods by mimicking shark skin,whale fin and owl wing,i.e.,riblet,leading-edge protuberance and trailing-edge serration,have been recently studied,and good progresses have been made in terms of effectiveness,analysis and mechanism.However,these potential techniques are unable to be widely applied within wind energy community due to the lack of reasonable modeling methods,clearly reflecting the effect of bionic structures on the flow field around,which results in incapability to carry out further optimal design of bionic blade.To this end,this review paper first concentrated on a summary of the control mechanisms of three bionic techniques.Based on this,some feasible ideas of model buildup were proposed.Finally,the flow analyses around the typical blade airfoils were chosen as case studies to verify the feasibility and accuracy of these simulation methods.
基金Supported by The 2011 Ministry of Health Key Clinical Speciality Center ProjectChina
文摘This study explored the clinical value of endoscopic ligation for the treatment of upper gastrointestinal(GI)protuberant lesions in children.According to the appearance and size of lesions,we used different ligation techniques for the treatment of the lesions.Endoscopic ultrasonography was used for preliminary characterization of the lesions.One case diagnosed with PeutzJeghers syndrome was successfully treated by a detachable snare.Two cases with semi-pedunculated or broad-base lesions originating from the submucosal layer of the upper GI were treated with endoscopic variceal ligation;endoscopic examination showed that one case had complete healing 11 wk after ligation,while an ulcer scar was observed at the ligation site after 6 wk in the other case.All lesions were successfully ligated at the first attempt.No significant complications occurred either during or after the procedure.Selective endoscopic ligation of upper GI lesions is an effective and safe treatment for upper GI protuberant lesions in children.
文摘The influence of the three-way interaction between the fungus (Curvularia protuberata), virus (CThTV), and tomato (Solanum lycopersicum) in combating drought stress was evaluated in this study. The plants in this greenhouse experiment were grown under conditions of 400 ± 150 μmol·m-2·s-1 photon flux density, 45% to 50% relative humidity (RH), and 30°C ± 2°C. Tomato seeds were germinated and inoculated with the combination of the fungus and virus at the seedling stage. The plants were allowed to grow for two weeks and randomly selected individuals were utilized. The selected plants were grown in one gallon pots containing organic potting soil. The treatments included non-symbiotic (NS), virus-free (VF), and symbiotic (An) plants. Each treatment received twelve samples and each sample was allowed to grow for an additional two weeks under drought stress. At that time, plants were exhibiting drought stress symptoms including visible wilting. Six samples from each treatment were utilized in determining selected physiological responses of tomato at pre-anthesis stage. The remaining six samples from each treatment were re-watered once and allowed to grow until they reached the anthesis stage. When they showed visible signs of wilting, the same physiological responses measured during pre-anthesis were conducted. The samples of each treatment were utilized at the end of each stage in determining photosynthetic rate, stomata conductance, photosynthetic pigments, water potential, and soluble sugar content. Plant growth, chlorophyll a, chlorophyll b, photosynthetic rate, stomata conductance, water potential, and soluble sugar content were similarly affected by the various treatments. However, carotenoids were significantly higher at pre-anthesis in the symbiotic plants in comparison to other treatments. Additionally, photosynthesis appeared to be significantly higher at anthesis compared to pre-anthesis for all treatments.
