【摘 要】
：
The detection of abnormal regions in complex structures is one of the most challenging targets for under-ground space engineering.Natural or artificial geologic variations reduce the effectiveness of conven-tional exploration methods.With the emergence of
【机 构】
：
School of Resources and Safety Engineering,Central South University,Changsha 410083,China
论文部分内容阅读
The detection of abnormal regions in complex structures is one of the most challenging targets for under-ground space engineering.Natural or artificial geologic variations reduce the effectiveness of conven-tional exploration methods.With the emergence of real-time monitoring,seismic wave velocity tomography allows the detection and imaging of abnormal regions to be accurate,intuitive,and quanti-tative.Since tomographic results are affected by multiple factors in practical small-scale applications,it is necessary to quantitatively investigate those influences.We adopted an improved three-dimensional(3D) tomography method combining passive acoustic emission acquisition and active ultrasonic mea-surements.By varying individual parameters (i.e.,prior model,sensor configuration,ray coverage,event distributions,and event location errors),37 comparative tests were conducted.The quantitative impact of different factors was obtained.Synthetic experiments showed that the method could effectively adapt to complex structures.The optimal input parameters based on quantization results can significantly improve the detection reliability in abnormal regions.
其他文献
背景:传统椎弓根螺钉在骨质疏松的腰椎内固定中存在螺钉松动的风险,皮质骨轨迹螺钉内固定可增加螺钉把持力,在骨科机器人的辅助下可提高置钉准确性,减少辐射伤害.目的:比较骨科机器人辅助与徒手皮质骨轨迹螺钉固定治疗合并骨质疏松腰椎退行性疾病的置钉准确性及安全性.方法:回顾分析2018年1月至2020年4月收治的39例合并骨质疏松的腰椎退行性疾病患者的临床资料,分为机器人组(19例)和徒手组(20例).收集两组数据,包括手术时间、透视次数、透视剂量、术中出血量、切口长度、住院费用、置钉精准率,同时对比术前、术后腰椎
背景:稳定性桡骨远端骨折经手法复位小夹板外固定能获得较满意疗效,但存在一定的盲目性,随着肌骨超声的发展,为引导辅助骨折复位、提高复位质量及成功率提供了可能性.目的:探讨高频超声引导下辅助手法复位并小夹板外固定治疗桡骨远端稳定性骨折的可行性.方法:2020年1-7月在自贡市第四人民医院诊断为单侧桡骨远端稳定性骨折患者100例,按照随机区组法分为试验组(50例)和对照组(50例),试验组患者接受高频超声引导下对桡骨远端骨折手法复位小夹板外固定,对照组采用徒手闭合复位小夹板外固定,采用改良Green与O\'
背景:全膝关节置换的成功需要在术中选取适宜的软组织松弛度,但不同患者术后的软组织变化情况不同.目的:探究全膝关节置换后中长期随访中膝关节软组织松弛度对患者满意度的影响,初步检验以长度测量膝关节软组织松弛度的效能.方法:选择在郑州大学第一附属医院行全膝关节置换且获得术后5-10年随访的患者107例,拍摄应力位X射线片,以不同方法测量双侧膝关节冠状位松弛度.①方法A:以内外翻应力试验中膝关节内外侧开口距离变化值之和表示膝关节松弛度,A1组(≥0 mm且≤5 mm,n=23),A2组(>5 mm且≤7 mm,n
背景:经皮骶髂螺钉内固定已经成为治疗骶髂关节分离的首选方法,但目前很多采用平行水平面的方式置入螺钉,此置钉方法风险相对较高,易受人体骨盆变异的影响,且很难实现双螺钉固定,需寻找一种新的内固定方式.目的:通过骨盆3D模型,模拟7.3 mm拉力螺钉固定骶髂关节,然后进行测量和统计分析,确定最佳髂骨进针点和空间角度.方法:用Mimics 21.0软件对60例骨盆CT数据进行3D重建,建立60例骨盆3D模型.从臀部外上方尽量靠近髂嵴上缘的位置,经S1椎弓根到S1椎体上1/3中点模拟置入7.3 mm拉力螺钉(尾向置
背景:椎弓根螺钉松动是脊柱内固定后的严重并发症,既往对螺钉松动的报道还是依赖CT轴位像进行判断.目的:对比研究CT冠状位重建图像及X射线片和轴位CT图像的传统方法在判定脊柱内固定螺钉松动的敏感度和特异性.方法:收集了23例在河南省人民医院行脊柱术后内固定翻修的病例,其中短节段固定14例,长节段固定患者9例,退变性疾病患者17例,骨折患者6例.术前采用CT冠状位重建图像以及传统X射线片和轴位CT图像两种方法进行椎弓根螺钉松动判定.2名医生独立阅片互不干扰,术前评估所有内固定装置是否存在松动.术中共探查螺钉1
The longitudinal immunologic status of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients and its association with the clinical outcome are barely known.Thus,we sought to ana-lyze the temporal profiles of specific antibodies,as
The coronavirus disease 2019 (COVID-19) pandemic increased the burden on many healthcare systems and in the process,exposed the need for medical resources and physical space.While few studies dis-cussed the efficient utilization of medical resources and p
Inherent drawbacks associated with drug-eluting stents have prompted the development of biore-sorbable cardiovascular stents.Additive manufacturing (3-dimentional (3D) printing) has been widely applied in medical devices.In this study,we develop a novel s
The coronavirus disease 2019 (COVID-19) pandemic is a global crisis,and medical systems in many coun-tries are overwhelmed with supply shortages and increasing demands to treat patients due to the surge in cases and severe illnesses.This study aimed to as
Coronavirus disease 2019 (COVID-19) deaths per million population in the countries of the West had often exceeded those in the countries of the East by factor of 100 by May 2021.In this paper,we refer to the West as represented by the United States plus t