The nonlinear evolution of rogue waves generated by means of wave focusing technique

Generating the rogue waves in offshore engineering is investigated,first of all,to forecast its occurrence to protect the offshore structure from being attacked,to study the mechanism and hydrodynamic properties of rouge wave experimentally as well as the rouge/structure interaction for the structure design.To achieve these purposes demands an accurate wave generation and calculation.In this paper,we establish a spatial domain model of fourth order nonlinear Schrdinger(NLS) equation for describing deep-water wave trains in the moving coordinate system.In order to generate rogue waves in the experimental tank efficiently,we take care that the transient water wave(TWW) determines precisely the concentration of time/place.First we simulate the three-dimensional wave using TWW in the numerical tank and modeling the deepwater basin with a double-side multi-segmented wave-maker in Shanghai Jiao Tong University(SJTU) under the linear superposing theory.To discuss its nonlinearity for guiding the experiment,we set the TWW as the initial condition of the NLS equation.The differences between the linear and nonlinear simulations are presented.Meanwhile,the characteristics of the transient water wave,including water particle velocity and wave slope,are investigated,which are important factors in safeguarding the offshore structures.

模块化手术流程下加速康复外科在腹腔镜膀胱癌根治性精准切除并回肠膀胱术中的应用

目的探讨模块化手术流程下加速康复外科(ERAS)在腹腔镜膀胱癌根治性精准切除并回肠膀胱术中的应用价值。方法回顾性选取2017年1月—2019年12月南部战区总医院泌尿外科施行的腹腔镜膀胱癌根治性精准切除并回肠膀胱术42例,根据围手术期采用的管理方法不同将其分为两组:ERAS管理组和常规管理组,每组各21例。其中ERAS管理组患者围手术期采用ERAS管理,常规管理组患者围手术期采用常规管理。比较两组患者的术后住院时间、首次排气时间、首次排便时间、首次下床时间、首次流食时间、术后疼痛视觉模拟评分(VAS),以及转铁蛋白、上臂肌围、体重指数、血浆白蛋白、总蛋白及前白蛋白等相关营养指标。正态分布的计量资料以均数±标准差(Mean±SD)表示,组间比较采用独立样本t检验;偏态分布的计量资料以中位数(四分位间距)[M(P_(25),P_(75))]表示,组间比较采用Mann-Whitney U检验;计数资料组间比较采用χ^(2)检验。结果ERAS组患者的术后住院时间为(8.9±1.8)d、首次排气时间为(33.4±3.2)h、首次排便时间为(60.3±7.8)h、首次下床活动时间为(23.1±6.7)h、首次流食时间为(82.7±18.5)h及术后VAS评分为(1.3±0.6)分,均较常规处理组明显减少[(12.3±2.3)d、(51.4±5.2)h、(73.0±8.1)h、(34.7±8.2)h、(109.7±21.6)h、(3.6±0.8)分],差异具有统计学意义(P<0.05)。ERAS组患者术后1周转铁蛋白下降值为[0.8(-0.4,2.2)g/L]、体重指数下降值为[(1.61±0.73)kg/m^(2)]、血浆白蛋白下降值为[(3.5±1.5)g/L]、总蛋白下降值为[(10.1±5.6)g/L]、前白蛋白下降值为[(90.5±11.3)mg/L],明显少于常规管理组[(1.9(0.9,3.6)g/L、(2.32±1.05)kg/m^(2)、(9.6±2.0)g/L、(16.3±4.9)g/L、(131.3±7.4)g/L],差异均具有统计学意义(P<0.05)。结论模块化腹腔镜膀胱癌根治性精准切除+回肠膀胱术后采取ERAS理念有利于缩短住院时间,减轻术后疼痛,对患者机体损耗及免疫功能的影响更小,能够加速患者术后的康复。