The sampling process is very inefficient for sam-pling-based motion planning algorithms that excess random sam-ples are generated in the planning space.In this paper,we pro-pose an adaptive space expansion(ASE)approac...The sampling process is very inefficient for sam-pling-based motion planning algorithms that excess random sam-ples are generated in the planning space.In this paper,we pro-pose an adaptive space expansion(ASE)approach which belongs to the informed sampling category to improve the sampling effi-ciency for quickly finding a feasible path.The ASE method enlarges the search space gradually and restrains the sampling process in a sequence of small hyper-ellipsoid ring subsets to avoid exploring the unnecessary space.Specifically,for a con-structed small hyper-ellipsoid ring subset,if the algorithm cannot find a feasible path in it,then the subset is expanded.Thus,the ASE method successively does space exploring and space expan-sion until the final path has been found.Besides,we present a particular construction method of the hyper-ellipsoid ring that uniform random samples can be directly generated in it.At last,we present a feasible motion planner BiASE and an asymptoti-cally optimal motion planner BiASE*using the bidirectional exploring method and the ASE strategy.Simulations demon-strate that the computation speed is much faster than that of the state-of-the-art algorithms.The source codes are available at https://github.com/shshlei/ompl.展开更多
BACKGROUND The retrospective review of I-ring pupil expansion ring use is designed to examine the patient characteristics and associated surgical challenges in a clinical practice.The hypothesis is that I-ring provide...BACKGROUND The retrospective review of I-ring pupil expansion ring use is designed to examine the patient characteristics and associated surgical challenges in a clinical practice.The hypothesis is that I-ring provides a necessary additive tool in dealing with challenging cataract surgeries with small pupils.AIM To document the safety profile and use of I-ring pupil expansion ring in a clinical practice.METHODS A retrospective chart review of 12 consecutive cases within the same year(2016)of cataract surgeries employing I-ring pupil expansion ring(Beaver-Visitec,International)by a single surgeon at the same ambulatory surgical center was conducted.Demographic,pre-op,intra-op,and post-op data were recorded.Total number of cataract cases performed was also recorded.RESULTS 8 of 12 cases were planned I-ring cases.1 case was decided intraoperatively when femtosecond laser caused the pupil to shrink.The other 3 cases were also decided upon intraoperatively when pupil was deemed to be small.7 patients had IFIS from Flomax use.2 patients had pseudoexfoliation syndrome as the cause of small pupil.2 patients had narrow angles with brunescent cataracts.2 patients had pre-op partial zonular dehiscence.1 patient had 360o of posterior synechiae.2 cases had ruptured posterior capsule that required anterior vitrectomy.No complications were attributed to the pupil expansion ring.A total of 296 cataract surgeries were performed that year by the surgeon,making the rate of pupil ring use 4.1%.CONCLUSION Small pupil requiring pupil expansion ring during cataract surgery is often associated with other challenges,such as brunescent cataract,zonular weakness,and posterior synechiae in this series.I-ring helped to reduce at least one challenge in these difficult cases.展开更多
Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering cons...Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering construction in expansive soil areas.Most of the existing studies evaluate the slope stability by analyzing the limit equilibrium state of the slope,and the analysis method for the stability evolution considering the damage softening of the shear zone is lacking.In this study,the large deformation shear mechanical behavior of expansive soil was investigated by ring shear test.The damage softening characteristic of expansive soil in the shear zone was analyzed,and a shear damage model reflecting the damage softening behavior of expansive soil was derived based on the damage theory.Finally,by skillfully combining the vector sum method and the shear damage model,an analysis method for the stability evolution of the expansive soil slope considering the shear zone damage softening was proposed.The results show that the shear zone subjected to large displacement shear deformation exhibits an obvious damage softening phenomenon.The damage variable equation based on the logistic function can be well used to describe the shear damage characteristics of expansive soil,and the proposed shear damage model is in good agreement with the ring shear test results.The vector sum method considering the damage softening behavior of the shear zone can be well applied to analyze the stability evolution characteristics of the expansive soil slope.The stability factor of the expansive soil slope decreases with the increase of shear displacement,showing an obvious progressive failure behavior.展开更多
Metal droplet deposition is a kind of additive manufacturing(3D Printing)technique that fabricates near-net part through droplets deposition with lower cost and higher efficiency.This paper proposed a solution to prob...Metal droplet deposition is a kind of additive manufacturing(3D Printing)technique that fabricates near-net part through droplets deposition with lower cost and higher efficiency.This paper proposed a solution to problems of electric power fittings that large inventories,high procurement costs,low manufacturing efficiency and transportation cost.Using additive Manufacturing technique-metal droplet deposition,electric power fittings fabricated on power construction site.This paper describes the manufacturing process of typical thin-walled samples(the structure optimized based on additive manufacturing principle)and ball head rings of electric power fittings.Aiming at the integral AM forming for ball and ball socket electric power fitting workpiece,a novel easy removal forming support material(ceramics and gypsum mixed with UV cured resin)have been developed.Here this support material was used to fabricate nested integral workpieces.Dimensional accuracy and microstructure of the test pieces were analyzed.The error of the height and width of the forming workpiece is within 5%.No obvious overlap trace(such as overlap line and cracks)observed,and the internal microstructure is equiaxial crystal.The average density of the component is 99.51%,which measured by drainage method and 13.39%higher than the cast raw material.展开更多
The relevant results of thermodynamics simulation test, recrystallization study and FEM numercal simulation are described. A method is also introduced that the controlled hot forming is carried out by adopting the pro...The relevant results of thermodynamics simulation test, recrystallization study and FEM numercal simulation are described. A method is also introduced that the controlled hot forming is carried out by adopting the program of expansion-extrusion compound forming.展开更多
基金supported in part by the National Natural Science Foun-dation of China(51975236)the National Key Research and Development Program of China(2018YFA0703203)the Innovation Project of Optics Valley Laboratory(OVL2021BG007)。
文摘The sampling process is very inefficient for sam-pling-based motion planning algorithms that excess random sam-ples are generated in the planning space.In this paper,we pro-pose an adaptive space expansion(ASE)approach which belongs to the informed sampling category to improve the sampling effi-ciency for quickly finding a feasible path.The ASE method enlarges the search space gradually and restrains the sampling process in a sequence of small hyper-ellipsoid ring subsets to avoid exploring the unnecessary space.Specifically,for a con-structed small hyper-ellipsoid ring subset,if the algorithm cannot find a feasible path in it,then the subset is expanded.Thus,the ASE method successively does space exploring and space expan-sion until the final path has been found.Besides,we present a particular construction method of the hyper-ellipsoid ring that uniform random samples can be directly generated in it.At last,we present a feasible motion planner BiASE and an asymptoti-cally optimal motion planner BiASE*using the bidirectional exploring method and the ASE strategy.Simulations demon-strate that the computation speed is much faster than that of the state-of-the-art algorithms.The source codes are available at https://github.com/shshlei/ompl.
基金Supported by a research grant from Beaver-Visited International,the manufacturer of the I-ring
文摘BACKGROUND The retrospective review of I-ring pupil expansion ring use is designed to examine the patient characteristics and associated surgical challenges in a clinical practice.The hypothesis is that I-ring provides a necessary additive tool in dealing with challenging cataract surgeries with small pupils.AIM To document the safety profile and use of I-ring pupil expansion ring in a clinical practice.METHODS A retrospective chart review of 12 consecutive cases within the same year(2016)of cataract surgeries employing I-ring pupil expansion ring(Beaver-Visitec,International)by a single surgeon at the same ambulatory surgical center was conducted.Demographic,pre-op,intra-op,and post-op data were recorded.Total number of cataract cases performed was also recorded.RESULTS 8 of 12 cases were planned I-ring cases.1 case was decided intraoperatively when femtosecond laser caused the pupil to shrink.The other 3 cases were also decided upon intraoperatively when pupil was deemed to be small.7 patients had IFIS from Flomax use.2 patients had pseudoexfoliation syndrome as the cause of small pupil.2 patients had narrow angles with brunescent cataracts.2 patients had pre-op partial zonular dehiscence.1 patient had 360o of posterior synechiae.2 cases had ruptured posterior capsule that required anterior vitrectomy.No complications were attributed to the pupil expansion ring.A total of 296 cataract surgeries were performed that year by the surgeon,making the rate of pupil ring use 4.1%.CONCLUSION Small pupil requiring pupil expansion ring during cataract surgery is often associated with other challenges,such as brunescent cataract,zonular weakness,and posterior synechiae in this series.I-ring helped to reduce at least one challenge in these difficult cases.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1509901).
文摘Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering construction in expansive soil areas.Most of the existing studies evaluate the slope stability by analyzing the limit equilibrium state of the slope,and the analysis method for the stability evolution considering the damage softening of the shear zone is lacking.In this study,the large deformation shear mechanical behavior of expansive soil was investigated by ring shear test.The damage softening characteristic of expansive soil in the shear zone was analyzed,and a shear damage model reflecting the damage softening behavior of expansive soil was derived based on the damage theory.Finally,by skillfully combining the vector sum method and the shear damage model,an analysis method for the stability evolution of the expansive soil slope considering the shear zone damage softening was proposed.The results show that the shear zone subjected to large displacement shear deformation exhibits an obvious damage softening phenomenon.The damage variable equation based on the logistic function can be well used to describe the shear damage characteristics of expansive soil,and the proposed shear damage model is in good agreement with the ring shear test results.The vector sum method considering the damage softening behavior of the shear zone can be well applied to analyze the stability evolution characteristics of the expansive soil slope.The stability factor of the expansive soil slope decreases with the increase of shear displacement,showing an obvious progressive failure behavior.
基金This research was funded by National Natural Science Foundation of China under grant number 51575313 and 51775420.This paper got help from Du Jun and Wang Xin of Xi’an Jiaotong University.
文摘Metal droplet deposition is a kind of additive manufacturing(3D Printing)technique that fabricates near-net part through droplets deposition with lower cost and higher efficiency.This paper proposed a solution to problems of electric power fittings that large inventories,high procurement costs,low manufacturing efficiency and transportation cost.Using additive Manufacturing technique-metal droplet deposition,electric power fittings fabricated on power construction site.This paper describes the manufacturing process of typical thin-walled samples(the structure optimized based on additive manufacturing principle)and ball head rings of electric power fittings.Aiming at the integral AM forming for ball and ball socket electric power fitting workpiece,a novel easy removal forming support material(ceramics and gypsum mixed with UV cured resin)have been developed.Here this support material was used to fabricate nested integral workpieces.Dimensional accuracy and microstructure of the test pieces were analyzed.The error of the height and width of the forming workpiece is within 5%.No obvious overlap trace(such as overlap line and cracks)observed,and the internal microstructure is equiaxial crystal.The average density of the component is 99.51%,which measured by drainage method and 13.39%higher than the cast raw material.
文摘The relevant results of thermodynamics simulation test, recrystallization study and FEM numercal simulation are described. A method is also introduced that the controlled hot forming is carried out by adopting the program of expansion-extrusion compound forming.
