In this paper, the behavior of barrel-vaulted structures undergoing rocking of the abutments and the effectiveness of a few retrofit solutions are discussed. The comprehension of the structural performance of vault-ab...In this paper, the behavior of barrel-vaulted structures undergoing rocking of the abutments and the effectiveness of a few retrofit solutions are discussed. The comprehension of the structural performance of vault-abutment systems is fundamental for their seismic vulnerability assessment, and for the design of efficient strengthening techniques. In the paper, traditional techniques such as extrados thin concrete slab or masonry spandrel walls as well as an innovative solution with an extrados thin improved lime mortar slab reinforced by means of glass fiber mesh are considered. The different strengthening solutions are studied and compared on the basis of the results of non linear numerical analyses and by reference to a simplified analytical approach. Numerical and analytical models are validated through comparison with the results of a recent experimental study focusing on the behavior of vaulted masonry structures subjected to rocking of the abutments. The validated models can be used by engineers for the seismic vulnerability assessment of masonry vaulted structures as well as for the proportioning of possible extrados strengthening solutions, and will be used in the future to explore different structural system configurations.展开更多
AIM:To determine the factors related to preoperative ocular characters that are predictive of insufficient vault(<250μm)after implantable collamer lens(ICL V4c;STAAR Surgical)implantation.METHODS:The participants ...AIM:To determine the factors related to preoperative ocular characters that are predictive of insufficient vault(<250μm)after implantable collamer lens(ICL V4c;STAAR Surgical)implantation.METHODS:The participants underwent ICL surgery and were divided into the low(<250μm)and normal(250-1000μm)vault groups based on the postoperative vault at 3mo.The preoperative biometric parameters and clinical outcomes were compared between the two groups.The relationship between the 3-month vault values and preoperative ocular parameters were evaluated by Generalized estimating equations.RESULTS:Sixteen(23 eyes)and 36 patients(63 eyes)were in the low and normal vault groups,respectively.All implantation procedures were uneventful with no cataract formation in the early postoperative period.The sulcusto-sulcus lens rise(STSL)and iris ciliary angle(ICA)were correlated with vault at 3mo after surgery.Every 0.1 mm increase in STSL was associated with 38.9μm decrease in the postoperative 3-month vault.A rise of 1 degree in ICA is associated with a reduction of 4μm in vault.CONCLUSION:Eyes with a narrow ciliary sulcus are associated with a higher rate of low vault after ICL implantation,suggesting a need for adjustments to the ICL size in these patients.Evaluating the characteristics of the ciliary sulcus contributes valuable information to predict low vault after surgery.展开更多
In accordance with the relative movement between end-milling cutter and workpiece surface, a theoretical generation model for milled surface was established with the movement error of principal axle considered. Then t...In accordance with the relative movement between end-milling cutter and workpiece surface, a theoretical generation model for milled surface was established with the movement error of principal axle considered. Then the milled surfaces under various cutting condition were simulated, the results of which showed that end milled surfaces were of "vaulted profile", heights of surface irregularty at various points to be different with maximum value in the middle and smaller at both sides, the difference were determined by diameter of milling cutter, feeding speed, ratio between the diameter of milling cutter and teeth point curve radius and width of workpiece. The study results can be applied to quality prediction of milled surfaces for precision and/or super precision milling operation.展开更多
AIM：To compare the agreement of anterior chamber depth（ACD）and central vault measurements obtained by anterior segment optical coherence tomography（AS-OCT）and ultrasound biomicroscopy（UBM）of post surgical high ...AIM：To compare the agreement of anterior chamber depth（ACD）and central vault measurements obtained by anterior segment optical coherence tomography（AS-OCT）and ultrasound biomicroscopy（UBM）of post surgical high myopic eyes with posterior chamber phakic intraocular lens（Visian ICL;STAAR Surgical）implantation.·METHODS：Fifty-two phakic eyes of 28 high myopic patients who underwent implantable Collamer lens（ICL）surgery for the correction of high myopia were studied.The postoperative ACD,the distance between the corneal endothelium and the anterior surface of ICL（cornea-ICL）and the central vault were measured with the AS-OCT system and the UBM system.Intraclass correlation coefficient（ICC）and the Bland-Altman plot were used to evaluate the repeatability and agreement of two devices.·R ESULTS：The mean ACD,cornea-ICL and central vault in the 52 phakic eyes after ICL surgery was 3.19±0.28 mm,2.47±0.28 mm,0.50±0.19 mm by AS-OCT and3.13±0.25 mm,2.49±0.25 mm,0.44±0.19 mm by UBM,respectively.Pairwise comparison of ACD and central vault measurements showed significant differences between AS-OCT and UBM（〈0.05）.However,no statistically significant difference was found between these imaging techniques in cornea-ICL（〉0.05）.The Pearson correlation coefficient（）between AS-OCT and UBM measurements for ACD,cornea-ICL and vault was0.88,0.80 and 0.89,respectively（〈0.001）.The ICC was0.89-0.94 for the measurements of AS-OCT and UBM.Bland-Altman analysis showed the 95%limits of agreement of ACD,cornea-ICL,central vault measurements between these two devices were-0.20 to 0.32 mm,-0.36to 0.32 mm and-0.12 to 0.24 mm,respectively.58·CONCLUSION：Central ACD and vault measurements using AS-OCT demonstrated a slight significantly higher value than using UBM in phakic eyes after ICL surgery.These two devices should not be used interchangeably for measurements of central ACD and vault in patients after phakic intraocular lens implantation.展开更多
Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underg...Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underground water seepage flow was taken into account or not. The distribution of displacement field around the multi-arch tunnel, which is influenced by the seepage field, was gained. The result indicates that the settlement values of the vault derived from coupling analysis are bigger when considering the seepage flow effect than that not considering. Through the contrast of arch subsidence quantities calculated by two kinds of computation situations, and the comparison between the calculated and measured value of tunnel vault settlement, it is found that the calculated value(5.7-6.0 mm) derived from considering the seepage effect is more close to the measured value(5.8-6.8 mm). Therefore, it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design.展开更多
文摘In this paper, the behavior of barrel-vaulted structures undergoing rocking of the abutments and the effectiveness of a few retrofit solutions are discussed. The comprehension of the structural performance of vault-abutment systems is fundamental for their seismic vulnerability assessment, and for the design of efficient strengthening techniques. In the paper, traditional techniques such as extrados thin concrete slab or masonry spandrel walls as well as an innovative solution with an extrados thin improved lime mortar slab reinforced by means of glass fiber mesh are considered. The different strengthening solutions are studied and compared on the basis of the results of non linear numerical analyses and by reference to a simplified analytical approach. Numerical and analytical models are validated through comparison with the results of a recent experimental study focusing on the behavior of vaulted masonry structures subjected to rocking of the abutments. The validated models can be used by engineers for the seismic vulnerability assessment of masonry vaulted structures as well as for the proportioning of possible extrados strengthening solutions, and will be used in the future to explore different structural system configurations.
基金Supported by National Natural Science Foundation of China(No.81900910)Natural Science Foundation of Zhejiang Province(No.LQ19H120003)Basic Scientific Research Project of Wenzhou(No.Y2023809).
文摘AIM:To determine the factors related to preoperative ocular characters that are predictive of insufficient vault(<250μm)after implantable collamer lens(ICL V4c;STAAR Surgical)implantation.METHODS:The participants underwent ICL surgery and were divided into the low(<250μm)and normal(250-1000μm)vault groups based on the postoperative vault at 3mo.The preoperative biometric parameters and clinical outcomes were compared between the two groups.The relationship between the 3-month vault values and preoperative ocular parameters were evaluated by Generalized estimating equations.RESULTS:Sixteen(23 eyes)and 36 patients(63 eyes)were in the low and normal vault groups,respectively.All implantation procedures were uneventful with no cataract formation in the early postoperative period.The sulcusto-sulcus lens rise(STSL)and iris ciliary angle(ICA)were correlated with vault at 3mo after surgery.Every 0.1 mm increase in STSL was associated with 38.9μm decrease in the postoperative 3-month vault.A rise of 1 degree in ICA is associated with a reduction of 4μm in vault.CONCLUSION:Eyes with a narrow ciliary sulcus are associated with a higher rate of low vault after ICL implantation,suggesting a need for adjustments to the ICL size in these patients.Evaluating the characteristics of the ciliary sulcus contributes valuable information to predict low vault after surgery.
文摘In accordance with the relative movement between end-milling cutter and workpiece surface, a theoretical generation model for milled surface was established with the movement error of principal axle considered. Then the milled surfaces under various cutting condition were simulated, the results of which showed that end milled surfaces were of "vaulted profile", heights of surface irregularty at various points to be different with maximum value in the middle and smaller at both sides, the difference were determined by diameter of milling cutter, feeding speed, ratio between the diameter of milling cutter and teeth point curve radius and width of workpiece. The study results can be applied to quality prediction of milled surfaces for precision and/or super precision milling operation.
文摘AIM：To compare the agreement of anterior chamber depth（ACD）and central vault measurements obtained by anterior segment optical coherence tomography（AS-OCT）and ultrasound biomicroscopy（UBM）of post surgical high myopic eyes with posterior chamber phakic intraocular lens（Visian ICL;STAAR Surgical）implantation.·METHODS：Fifty-two phakic eyes of 28 high myopic patients who underwent implantable Collamer lens（ICL）surgery for the correction of high myopia were studied.The postoperative ACD,the distance between the corneal endothelium and the anterior surface of ICL（cornea-ICL）and the central vault were measured with the AS-OCT system and the UBM system.Intraclass correlation coefficient（ICC）and the Bland-Altman plot were used to evaluate the repeatability and agreement of two devices.·R ESULTS：The mean ACD,cornea-ICL and central vault in the 52 phakic eyes after ICL surgery was 3.19±0.28 mm,2.47±0.28 mm,0.50±0.19 mm by AS-OCT and3.13±0.25 mm,2.49±0.25 mm,0.44±0.19 mm by UBM,respectively.Pairwise comparison of ACD and central vault measurements showed significant differences between AS-OCT and UBM（〈0.05）.However,no statistically significant difference was found between these imaging techniques in cornea-ICL（〉0.05）.The Pearson correlation coefficient（）between AS-OCT and UBM measurements for ACD,cornea-ICL and vault was0.88,0.80 and 0.89,respectively（〈0.001）.The ICC was0.89-0.94 for the measurements of AS-OCT and UBM.Bland-Altman analysis showed the 95%limits of agreement of ACD,cornea-ICL,central vault measurements between these two devices were-0.20 to 0.32 mm,-0.36to 0.32 mm and-0.12 to 0.24 mm,respectively.58·CONCLUSION：Central ACD and vault measurements using AS-OCT demonstrated a slight significantly higher value than using UBM in phakic eyes after ICL surgery.These two devices should not be used interchangeably for measurements of central ACD and vault in patients after phakic intraocular lens implantation.
基金Project(50490274) supported by the National Natural Science Foundation of ChinaProject(200516) supported by Hunan Transportation Science and Technology
文摘Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underground water seepage flow was taken into account or not. The distribution of displacement field around the multi-arch tunnel, which is influenced by the seepage field, was gained. The result indicates that the settlement values of the vault derived from coupling analysis are bigger when considering the seepage flow effect than that not considering. Through the contrast of arch subsidence quantities calculated by two kinds of computation situations, and the comparison between the calculated and measured value of tunnel vault settlement, it is found that the calculated value(5.7-6.0 mm) derived from considering the seepage effect is more close to the measured value(5.8-6.8 mm). Therefore, it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design.
