BACKGROUND Overhanging filtering bleb is a common complication after trabeculectomy and surgical repair is an effective treatment when the patient presents with apparent symptoms.Filtering bleb relevant infection incl...BACKGROUND Overhanging filtering bleb is a common complication after trabeculectomy and surgical repair is an effective treatment when the patient presents with apparent symptoms.Filtering bleb relevant infection including in the filtering bleb itself and even endophthalmitis in some severe cases has been reported.However,corneal fungal infection after filtering bleb repair is rarely reported.CASE SUMMARY A 57-year-old Chinese man who had sensations of redness and foreign body sensations in the left eye 3 wk after repair of overhanging filtering bleb.3 wk ago,due to sensations of a foreign body in the left eye for 3 years with worsening for 3 mo.The patient was diagnosed as overhanging filtering bleb and underwent a repair of overhanging filtering bleb.Postoperative,the filtering bleb formed well and the intraocular pressure is normal.But the patient gradually develop redness,pain and a grey infiltrate of the cornea in the eye.Finally it developed into fungal corneal ulcer.Through asking the medical history,we found the patient had irregularly self-medicated for years with glucocorticoid eye drops for years to relieve the foreign body sensation in the eye caused by filtering bleb overhanging.Because the glucocorticoid eye drops he used years ago had provide normal sensation to the eye.After 3 mo of anti-fungal treatment,the inflammation was controlled.CONCLUSION In addition to avoiding the development of overhanging filtering bleb after trabeculectomy,the present case report also suggests that clinicians should pay more attention to the patient’s ocular self-medication history.Particularly in patients with a history of glaucoma or eye surgery.Because these patients may be exposed to more types of eye drops than other individuals,they may select the wrong medi-cations for long-term use,based on their previous experience.展开更多
A 74-year-old man presented with a three-year history of foreign body sensation in the right eye after cataract surgery.He underwent uneventful trabeculectomy with mitomycin C(MMC) in the right eye seven years ago.Sli...A 74-year-old man presented with a three-year history of foreign body sensation in the right eye after cataract surgery.He underwent uneventful trabeculectomy with mitomycin C(MMC) in the right eye seven years ago.Slit-lamp examination revealed a large avascular filtration bleb overhanging on the cornea with a thin base connected to the conjunctiva.Preoperative ultrasound biomicroscopy(UBM) impressions were confirmed by leakage of aqueous from the incision intraoperatively.Surgical dissection and revision of the bleb was performed with satisfactory outcome.Histopathologic evaluation showed proliferation of fibrous tissue under the conjunctival epithelia with irregular cystoids change.The current case may be the first report of a post-trabeculectomy overhanging filtration bleb related to cataract surgery.The possible mechanism may be related to microleakage of the surgical wound after phacoemulsification which initiated the healing and scarring process.展开更多
Controlling the overhang surface quality is still a formidable challenge in manufacturing the components with complex structures during laser powder bed fusion(LPBF).This study systematically uncovers the effects of t...Controlling the overhang surface quality is still a formidable challenge in manufacturing the components with complex structures during laser powder bed fusion(LPBF).This study systematically uncovers the effects of the volume energy density(VED)and overhang angle on the evolution of surface morphology and corresponding surface roughness(Ra)of top and down-skin surfaces of IN718 superalloy samples.The results show that balling,Plateau-Rayleigh instability,open pore and humping caused by the material stacking are the main factors contributing to the apparent deterioration of top surface quality.When the VED is 80–100 J/mm^(3),the high down-skin surface roughness is attributed to the serious dross caused by recoil pressure and sinking of the melt pool.Using insufficient VED(15–50 J/mm^(3))can easily lead to poor metallurgical bonding and material spalling on the down-skin surface.In addition,overhang angle also significantly affects down-skin surface roughness due to the stair effect and the adhered unmelted powders.An improvement in the surface quality of down-skin surface is observed when the overhang angle increases.Based on the finding of this investigation,an optical VED(59.5 J/mm^(3))significantly improves the top and down-skin surface quality and porosity of overhang samples.This study provides an insight into synergy ascension of the top and down-skin surface quality in the overhang structure.展开更多
This paper studies additive manufacturing(AM) oriented structural topology optimization(TO).The minimum compliance design subject to overhang angle constraint with overhang length relaxation and horizontal minimum len...This paper studies additive manufacturing(AM) oriented structural topology optimization(TO).The minimum compliance design subject to overhang angle constraint with overhang length relaxation and horizontal minimum length control is considered.Although the overhang length relaxation allows additional flexibility for AM product design,there have been very limited studies on it.This paper elucidates that the overhang angle constraint we proposed can identify the lower boundary element that violates the overhang angle constraint.Taking advantage of this fact,we achieve the overhang length relaxation by specifying that the volume fraction of the elements that violate the overhang angle constraint in each local area of the design domain is less than a specified upper bound.A formula for estimating the maximum allowable overhang length of this method is proposed and verified.The horizontal minimum length constraint is also employed in this paper.While controlling the horizontal length size of the structural member,this constraint together with the overhang angle constraint with overhang length relaxation suppresses the hanging feature.The gradient-based optimization algorithm method of moving asymptotic(MMA) is used to solve the TO formulation.Numerical examples show the effectiveness of this method.It is observed that the new constraint alleviates the main issues of traditional overhang angle constraints,i.e.,gray element issue,stress concentration issue,and shattered structure issue.Compared with the strict traditional overhang angle constraint,the new formulation reduces structural compliance.展开更多
To study the nonlinear dynamic behavior of the bladed overhang rotor system with squeeze film damper (SFD), a blade-overhang rotor-SFD model is formulated using the lumped mass method and the Lagrange approach. The ca...To study the nonlinear dynamic behavior of the bladed overhang rotor system with squeeze film damper (SFD), a blade-overhang rotor-SFD model is formulated using the lumped mass method and the Lagrange approach. The cavitated short bearing model is employed to describe the nonlinear oil force of the SFD. To reduce the scale of the nonlinear coupling system, a set of orthogonal transformations is employed to decouple the one nodal diameter equations of blades, which are coupled with the dy- namical equations of the rotor, with other equations of blades. In this way, the original system with 16+4n (n≥3) degrees of freedom (DoF) is reduced to a system with 24 DoF only. Then the parametric excitation terms in the blade-overhang rotor-SFD model are simplified in terms of periodic transforma- tions. The coupling equations are numerically solved and the solutions are used to analyze the dy- namic behavior of the system in terms of the bifurcation diagram, whirl orbit, Poincaré map and spec- trum plot. A variety of motion types are found such as multi-periodic, quasi-periodic, and chaotic mo- tions. Moreover, the typical nonlinear dynamic evolutions including the periodic-doubling bifurcation and reverse bifurcation are noted. It is noticed that there exist apparent differences in the dynamic behavior between the blade-overhang rotor-SFD models without and with considering the effect of blades.展开更多
基金Supported by the Science and Technology Project of Education Department of Jilin Province,No.JJKH20201089KJ.
文摘BACKGROUND Overhanging filtering bleb is a common complication after trabeculectomy and surgical repair is an effective treatment when the patient presents with apparent symptoms.Filtering bleb relevant infection including in the filtering bleb itself and even endophthalmitis in some severe cases has been reported.However,corneal fungal infection after filtering bleb repair is rarely reported.CASE SUMMARY A 57-year-old Chinese man who had sensations of redness and foreign body sensations in the left eye 3 wk after repair of overhanging filtering bleb.3 wk ago,due to sensations of a foreign body in the left eye for 3 years with worsening for 3 mo.The patient was diagnosed as overhanging filtering bleb and underwent a repair of overhanging filtering bleb.Postoperative,the filtering bleb formed well and the intraocular pressure is normal.But the patient gradually develop redness,pain and a grey infiltrate of the cornea in the eye.Finally it developed into fungal corneal ulcer.Through asking the medical history,we found the patient had irregularly self-medicated for years with glucocorticoid eye drops for years to relieve the foreign body sensation in the eye caused by filtering bleb overhanging.Because the glucocorticoid eye drops he used years ago had provide normal sensation to the eye.After 3 mo of anti-fungal treatment,the inflammation was controlled.CONCLUSION In addition to avoiding the development of overhanging filtering bleb after trabeculectomy,the present case report also suggests that clinicians should pay more attention to the patient’s ocular self-medication history.Particularly in patients with a history of glaucoma or eye surgery.Because these patients may be exposed to more types of eye drops than other individuals,they may select the wrong medi-cations for long-term use,based on their previous experience.
基金supported by the Natural Science Foundation of Guangdong Province in China(grant No.2015A030313052)
文摘A 74-year-old man presented with a three-year history of foreign body sensation in the right eye after cataract surgery.He underwent uneventful trabeculectomy with mitomycin C(MMC) in the right eye seven years ago.Slit-lamp examination revealed a large avascular filtration bleb overhanging on the cornea with a thin base connected to the conjunctiva.Preoperative ultrasound biomicroscopy(UBM) impressions were confirmed by leakage of aqueous from the incision intraoperatively.Surgical dissection and revision of the bleb was performed with satisfactory outcome.Histopathologic evaluation showed proliferation of fibrous tissue under the conjunctival epithelia with irregular cystoids change.The current case may be the first report of a post-trabeculectomy overhanging filtration bleb related to cataract surgery.The possible mechanism may be related to microleakage of the surgical wound after phacoemulsification which initiated the healing and scarring process.
基金This work was supported by the National Natural Science Foundation of China(Nos.52130204,52174376)the Guangdong Basic and Applied Basic Research Foundation(No.2021B1515120028)+5 种基金the Science and Technology Innovation Team Plan of Shaan Xi Province(No.2021TD-17)the Youth Innovation Team of Shaanxi Universities,Thousands Person Plan of Jiangxi Province(No.JXSQ2020102131)the Joint Research Funds of the Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University(No.2020GXLH-Z-024)the Science Research Funds of Xi'an City(No.21ZCZZHXJS-QCY6-005)the Fundamental Research Funds for the Central Universities(No.D5000210902)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Nos.CX2021056,CX2021066,CX2022033),China.
文摘Controlling the overhang surface quality is still a formidable challenge in manufacturing the components with complex structures during laser powder bed fusion(LPBF).This study systematically uncovers the effects of the volume energy density(VED)and overhang angle on the evolution of surface morphology and corresponding surface roughness(Ra)of top and down-skin surfaces of IN718 superalloy samples.The results show that balling,Plateau-Rayleigh instability,open pore and humping caused by the material stacking are the main factors contributing to the apparent deterioration of top surface quality.When the VED is 80–100 J/mm^(3),the high down-skin surface roughness is attributed to the serious dross caused by recoil pressure and sinking of the melt pool.Using insufficient VED(15–50 J/mm^(3))can easily lead to poor metallurgical bonding and material spalling on the down-skin surface.In addition,overhang angle also significantly affects down-skin surface roughness due to the stair effect and the adhered unmelted powders.An improvement in the surface quality of down-skin surface is observed when the overhang angle increases.Based on the finding of this investigation,an optical VED(59.5 J/mm^(3))significantly improves the top and down-skin surface quality and porosity of overhang samples.This study provides an insight into synergy ascension of the top and down-skin surface quality in the overhang structure.
基金supported by the National Natural Science Foundation of China (Grant Nos.52075070 and 12032008)。
文摘This paper studies additive manufacturing(AM) oriented structural topology optimization(TO).The minimum compliance design subject to overhang angle constraint with overhang length relaxation and horizontal minimum length control is considered.Although the overhang length relaxation allows additional flexibility for AM product design,there have been very limited studies on it.This paper elucidates that the overhang angle constraint we proposed can identify the lower boundary element that violates the overhang angle constraint.Taking advantage of this fact,we achieve the overhang length relaxation by specifying that the volume fraction of the elements that violate the overhang angle constraint in each local area of the design domain is less than a specified upper bound.A formula for estimating the maximum allowable overhang length of this method is proposed and verified.The horizontal minimum length constraint is also employed in this paper.While controlling the horizontal length size of the structural member,this constraint together with the overhang angle constraint with overhang length relaxation suppresses the hanging feature.The gradient-based optimization algorithm method of moving asymptotic(MMA) is used to solve the TO formulation.Numerical examples show the effectiveness of this method.It is observed that the new constraint alleviates the main issues of traditional overhang angle constraints,i.e.,gray element issue,stress concentration issue,and shattered structure issue.Compared with the strict traditional overhang angle constraint,the new formulation reduces structural compliance.
基金Supported by the National Natural Science Foundation of China (Grant No. 10632040)the Natural Science Foundation of Hei-Long-Jiang Province of China (Grant No. ZJG0704)the Harbin Science & Technology Innovative Foundation of China (Grant No. 2007RFLXG009)
文摘To study the nonlinear dynamic behavior of the bladed overhang rotor system with squeeze film damper (SFD), a blade-overhang rotor-SFD model is formulated using the lumped mass method and the Lagrange approach. The cavitated short bearing model is employed to describe the nonlinear oil force of the SFD. To reduce the scale of the nonlinear coupling system, a set of orthogonal transformations is employed to decouple the one nodal diameter equations of blades, which are coupled with the dy- namical equations of the rotor, with other equations of blades. In this way, the original system with 16+4n (n≥3) degrees of freedom (DoF) is reduced to a system with 24 DoF only. Then the parametric excitation terms in the blade-overhang rotor-SFD model are simplified in terms of periodic transforma- tions. The coupling equations are numerically solved and the solutions are used to analyze the dy- namic behavior of the system in terms of the bifurcation diagram, whirl orbit, Poincaré map and spec- trum plot. A variety of motion types are found such as multi-periodic, quasi-periodic, and chaotic mo- tions. Moreover, the typical nonlinear dynamic evolutions including the periodic-doubling bifurcation and reverse bifurcation are noted. It is noticed that there exist apparent differences in the dynamic behavior between the blade-overhang rotor-SFD models without and with considering the effect of blades.
