Soft computing tools in the form of combination of multiple nonlinear regression and M5′ model tree were used for estimation of overtopping rate at the vertical coastal structures. For reliable and precise estimation...Soft computing tools in the form of combination of multiple nonlinear regression and M5′ model tree were used for estimation of overtopping rate at the vertical coastal structures. For reliable and precise estimation of overtopping rate, the experimental data available in the database CLASH were used. The dimensionless overtopping rate was estimated in terms of conventional dimensionless parameters including the relative crest freeboard Rc/Hs, seabed slope tanθ, deep water wave steepness S（om）, surf similarity ξ（om） and local relative water depth ht/Hs. The accuracy of the new model was compared with other existing models and also evaluated with some field measurements. The results indicated that the model presented in this paper is more accurate than other existing models. With statistical parameters, it is shown that the accuracy of predictions in the new model is better than that of other models.展开更多
When a 2-D progressive wave train normally or obliquely approaches a vertical wall and then is normally or obliquely reflected from it, the combination of the approaching and reflected waves may result in a standing w...When a 2-D progressive wave train normally or obliquely approaches a vertical wall and then is normally or obliquely reflected from it, the combination of the approaching and reflected waves may result in a standing wave or a short-crested wave in front of the wall. This paper presents the experimental observations of sand bed configurations under the action of these water waves in front of the wall. The geometry of sand ripples under these water waves in front of the vertical wall is presented as a function of flow parameters, such as the water particle semi-excursion and the mobility number.展开更多
This study examines the hydrodynamic performance of short-crested wave interaction with a new porous cylindrical structure by using the scaled boundary finite element method （SBFEM）, which is a semi-analytical techn...This study examines the hydrodynamic performance of short-crested wave interaction with a new porous cylindrical structure by using the scaled boundary finite element method （SBFEM）, which is a semi-analytical technique combining the advantages of the finite element method and the boundary element method and with its own special features as well. The cylindrical structure consists of dual arc-shaped porous outer cylinders circumscribing an impermeable inner cylinder. A central feature of the newly extended method is that two virtual outer cylinders extending the arc-shaped porous outer cylinders with the same centre are introduced and variable porous-effect parameters are also introduced for the two virtual cylinders, so that the final SBFEM quation still can be handled in a closed-form analytical manner in the radial direction and by a finite element approximation in the circumferential direction. The entire computational domain is divided into two bounded and one unbounded domains, and a variational principle formulation is used to derive the SBFEM equation in each sub-domain. The velocity potential in bounded and unbounded domains is formulated using sets of Bessel and Hankel functions respectively, and the unknown coefficients are determined from the matching conditions. The results of numerical verification show that the approach discretises only the outermost virtual cylinder with surface finite-elements and fewer elements are required to obtain very accurate results.Influences of the incident wave parameters and structural configurations on the hydrodynamics are examined.展开更多
目的探讨伴有牙源性上颌窦炎(odontogenic maxillary sinusitis,OMS)患牙拔除后因骨量不足行上颌窦底提升术及种植修复的临床效果,为临床提供参考。方法本研究已通过单位伦理委员会审查批准,并获得患者知情同意。上颌后牙区患牙无保留...目的探讨伴有牙源性上颌窦炎(odontogenic maxillary sinusitis,OMS)患牙拔除后因骨量不足行上颌窦底提升术及种植修复的临床效果,为临床提供参考。方法本研究已通过单位伦理委员会审查批准,并获得患者知情同意。上颌后牙区患牙无保留价值且确诊为OMS,拔牙后6~8个月骨高度不足行上颌窦底提升术及同期种植45例作为研究组。同期随机纳入上颌后牙区患牙无保留价值但未诊断为OMS,拔牙后6~8个月因种植区域骨高度不足行上颌窦底提升术及同期种植48例作为对照组。研究组中部分上颌窦底骨质不连续及上颌窦底剩余牙槽骨高度<4 mm的病例行侧壁开窗上颌窦底提升术共13例,其余32例行穿嵴顶上颌窦底提升术。对照组上颌窦底剩余牙槽骨高度<4 mm的病例行侧壁开窗上颌窦底提升术共8例,其余40例行穿嵴顶上颌窦底提升术。种植术后6~8个月行二期修复治疗。种植术后21 d、3个月、8个月及修复后每6个月进行随访,修复后24个月比较2组上颌窦内成骨高度(sinus bone gain,SBG)、种植体尖端成骨高度(apical bone height,ABH)和种植体边缘骨吸收(marginal bone loss,MBL)情况。结果研究组45例种植术前上颌窦黏膜厚度均值(1.556±0.693)mm,大于对照组(1.229±0.425)mm,差异有统计学意义(P<0.001),但上颌窦底提升术均无上颌窦黏膜穿孔。修复后24个月,研究组SBG、ABH和MBL与对照组差异均无统计学意义(P>0.05)。结论伴OMS的患牙拔除后,上颌窦炎症减退、缺牙区骨质高度和密度得到一定程度的恢复,通过上颌窦底提升手术及种植修复,可以达到与非OMS患牙拔除后上颌窦底提升术及种植修复同样的效果。展开更多
文摘Soft computing tools in the form of combination of multiple nonlinear regression and M5′ model tree were used for estimation of overtopping rate at the vertical coastal structures. For reliable and precise estimation of overtopping rate, the experimental data available in the database CLASH were used. The dimensionless overtopping rate was estimated in terms of conventional dimensionless parameters including the relative crest freeboard Rc/Hs, seabed slope tanθ, deep water wave steepness S（om）, surf similarity ξ（om） and local relative water depth ht/Hs. The accuracy of the new model was compared with other existing models and also evaluated with some field measurements. The results indicated that the model presented in this paper is more accurate than other existing models. With statistical parameters, it is shown that the accuracy of predictions in the new model is better than that of other models.
文摘When a 2-D progressive wave train normally or obliquely approaches a vertical wall and then is normally or obliquely reflected from it, the combination of the approaching and reflected waves may result in a standing wave or a short-crested wave in front of the wall. This paper presents the experimental observations of sand bed configurations under the action of these water waves in front of the wall. The geometry of sand ripples under these water waves in front of the vertical wall is presented as a function of flow parameters, such as the water particle semi-excursion and the mobility number.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51121005 and 51138001)the China-Germany Joint Research Project (Grant No. GZ566)
文摘This study examines the hydrodynamic performance of short-crested wave interaction with a new porous cylindrical structure by using the scaled boundary finite element method （SBFEM）, which is a semi-analytical technique combining the advantages of the finite element method and the boundary element method and with its own special features as well. The cylindrical structure consists of dual arc-shaped porous outer cylinders circumscribing an impermeable inner cylinder. A central feature of the newly extended method is that two virtual outer cylinders extending the arc-shaped porous outer cylinders with the same centre are introduced and variable porous-effect parameters are also introduced for the two virtual cylinders, so that the final SBFEM quation still can be handled in a closed-form analytical manner in the radial direction and by a finite element approximation in the circumferential direction. The entire computational domain is divided into two bounded and one unbounded domains, and a variational principle formulation is used to derive the SBFEM equation in each sub-domain. The velocity potential in bounded and unbounded domains is formulated using sets of Bessel and Hankel functions respectively, and the unknown coefficients are determined from the matching conditions. The results of numerical verification show that the approach discretises only the outermost virtual cylinder with surface finite-elements and fewer elements are required to obtain very accurate results.Influences of the incident wave parameters and structural configurations on the hydrodynamics are examined.
文摘目的探讨伴有牙源性上颌窦炎(odontogenic maxillary sinusitis,OMS)患牙拔除后因骨量不足行上颌窦底提升术及种植修复的临床效果,为临床提供参考。方法本研究已通过单位伦理委员会审查批准,并获得患者知情同意。上颌后牙区患牙无保留价值且确诊为OMS,拔牙后6~8个月骨高度不足行上颌窦底提升术及同期种植45例作为研究组。同期随机纳入上颌后牙区患牙无保留价值但未诊断为OMS,拔牙后6~8个月因种植区域骨高度不足行上颌窦底提升术及同期种植48例作为对照组。研究组中部分上颌窦底骨质不连续及上颌窦底剩余牙槽骨高度<4 mm的病例行侧壁开窗上颌窦底提升术共13例,其余32例行穿嵴顶上颌窦底提升术。对照组上颌窦底剩余牙槽骨高度<4 mm的病例行侧壁开窗上颌窦底提升术共8例,其余40例行穿嵴顶上颌窦底提升术。种植术后6~8个月行二期修复治疗。种植术后21 d、3个月、8个月及修复后每6个月进行随访,修复后24个月比较2组上颌窦内成骨高度(sinus bone gain,SBG)、种植体尖端成骨高度(apical bone height,ABH)和种植体边缘骨吸收(marginal bone loss,MBL)情况。结果研究组45例种植术前上颌窦黏膜厚度均值(1.556±0.693)mm,大于对照组(1.229±0.425)mm,差异有统计学意义(P<0.001),但上颌窦底提升术均无上颌窦黏膜穿孔。修复后24个月,研究组SBG、ABH和MBL与对照组差异均无统计学意义(P>0.05)。结论伴OMS的患牙拔除后,上颌窦炎症减退、缺牙区骨质高度和密度得到一定程度的恢复,通过上颌窦底提升手术及种植修复,可以达到与非OMS患牙拔除后上颌窦底提升术及种植修复同样的效果。
