上层建筑一体化船型有效度与应力预报

[目的]给出一种快速准确地估算含上层建筑船型总纵弯曲应力的方法。[方法]在前人研究的基础上,以某典型一体化上层建筑船型为对象,采用有限元数值仿真计算方法,对多种不同上层建筑的船舶进行有限元建模计算,结合3种定义方法计算上层建筑有效度,与采用常用的上层建筑有效度简化计算公式(英国劳氏规范经验公式、俄罗斯公式1、俄罗斯公式2)的结果进行对比。[结果]结果表明,这些简化计算公式在上层建筑中部区域附近的有效度预报值差别不大,与有限元值较为接近,但在远离中部区域时误差较大。而对不同长度、高度、厚度的有效度计算结果的对比表明,俄罗斯公式1计算得到的有效度与第3种定义方法的结果吻合度高,其与该定义方法结合后预报的应力值与有限元计算结果误差小。[结论]所提方法可作为一体化上层建筑船型船体梁弯曲应力的预报方法之一。

输尿管软镜碎石术后无管化的临床研究

目的:探讨术后留置双J管对单侧中上盏肾结石输尿管软镜碎石术(FURL)后疗效及安全性。方法:回顾性分析2019年4月至2021年10月安徽省阜阳市第二人民医院泌尿外科接受FURL术单侧中上盏肾结石患者122例,根据术后是否留置双J管分为未置管组57例和置管组65例。比较两组患者结石清除率、手术时间、住院时间、并发症及腰腹疼痛发生情况。结果:全部患者均顺利完成手术,镜鞘置入顺利,未见输尿管或肾脏黏膜损伤。相比未置管组,置管组手术时间长[(52.05±12.17)vs.(48.87±10.84)min],术后血尿[55.38%(36/65)vs.26.32%(15/57)]和膀胱刺激发生率[33.85%(22/65)vs.12.28%(7/57)]、术后7d、14d和28d腰腹疼痛发生率[55.38%vs.33.33%;41.54%vs.15.79%;36.92%vs.3.51%]高,差异具有统计学意义(P<0.05)。结论:对于基础身体机能状态较好、结石负荷较低的单侧中上盏肾结石患者,FURL术后不留置双J管更有助于缩短手术时间,降低术后血尿和膀胱刺激发生风险。

Measurement of Urban Economic Gravity of China’s Three Major Agglomerations and Its Implications for the Coordinated Development of the Beijing-Tianjin-Hebei Region

This paper adopts the perspective of urban economic linkage and the modified urban economic gravity model to conduct a comparative analysis of the economic gravity among cities in China’s three major urban agglomerations,including the Beijing-Tianjin-Hebei region,the Yangtze River Delta,and the Pearl River Delta.The results show that,despite the ever-tightening economic linkages among cities in the urban agglomerations,the development of the Beijing-Tianjin-Hebei region falls behind that of the Yangtze River Delta and the Pearl River Delta in terms of coordination,closeness,and balance.The economic linkages among cities in the Beijing-Tianjin-Hebei region are not as cohesive as they could be and display a significant“siphon effect”through Beijing and Tianjin as well as a prominently unidirectional economic flow.This study suggests that efforts should be put into directing the orderly flow of resources from Beijing and Tianjin to cities in Hebei and promoting a balanced economic flow among cities,thus facilitating the coordination of regional development.