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C臂X射线机下整复纠正Baumann角与三维移位 被引量:1
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作者 胡伟文 刘文和 +5 位作者 陈鹏 李杨 曹锡文 唐新文 郭志文 王福剑 《中国组织工程研究与临床康复》 CAS CSCD 北大核心 2008年第52期10268-10271,共4页
目的:研究证明,Baumann角与提携角存在显著负相关,肱骨骨折复位时通过测量Baumann角可以预测提携角,能有效地防止肘内翻。观察C臂X射线机透视下闭合复位过程中测量并纠正Baumann角及三维移位后,经皮克氏针交叉内固定对儿童肱骨髁上骨折... 目的:研究证明,Baumann角与提携角存在显著负相关,肱骨骨折复位时通过测量Baumann角可以预测提携角,能有效地防止肘内翻。观察C臂X射线机透视下闭合复位过程中测量并纠正Baumann角及三维移位后,经皮克氏针交叉内固定对儿童肱骨髁上骨折的整复效果。方法:经皮克氏针交叉内固定治疗儿童肱骨髁上骨折68例,其中尺偏型49例,桡偏型16例;屈曲型3例。在C臂X射线机透视下,闭合复位骨折的三维移位,强调完全纠正尺偏移位及内倾,测量并纠正患侧Baumann角,术中、术后应用X射线片测量与健侧Baumann角的差值,结果评估参照Flynn标准。结果:68例患儿均获随访,平均随访36.1个月。最后1次随访,患侧Baumann角平均73.4°,健侧平均72.4°;提携角患侧平均7.7°,健侧平均9.6°,12例提携角减少5°~10°,其中5例发生轻度肘内翻。患侧肘关节伸屈功能平均为-6.5°(伸)136.5°(屈)。68例患儿骨折全部愈合,无一例发生Volkmann挛缩。根据Flynn评估标准,术后3d内测量68例患儿中0°<与健侧Baumann角度差<2°者46例,优良率为95.24%;2°≤与健侧Baumann角度差<4°者17例,优良率为85.71%;与健侧Baumann角度差≥4°者5例,优良率为20.00%。与健侧Baumann角度差<4°者的疗效优良率显著高于与健侧Baumann角度差≥4°者(χ2=22.7121,7.3634,P<0.05)。结论:在C臂X射线机透视下整复纠正三维移位,强调完全纠正尺偏移位及内倾,Baumann角恢复满意后,采用经皮克氏针固定,固定可靠,能有效避免肘内翻,防止前臂Volkmann挛缩的发生,肘关节功能恢复满意。 展开更多
关键词 C臂X射线机 三维移位 BAUMANN角 肱骨骨折
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一种动态密钥与DNA交错编码的多图像加密算法
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作者 陈善学 杜文正 任丽丹 《电讯技术》 北大核心 2023年第4期529-535,共7页
针对目前多图像加密算法中置乱效果不佳、DNA编码模式固定及密钥更新方式实用性低等问题,提出了一种基于动态密钥更新与DNA动态交错编码的加密方案。首先,设计了一种利用SHA-256的动态密钥更新方案,通过限制新密钥中的明文信息量摆脱一... 针对目前多图像加密算法中置乱效果不佳、DNA编码模式固定及密钥更新方式实用性低等问题,提出了一种基于动态密钥更新与DNA动态交错编码的加密方案。首先,设计了一种利用SHA-256的动态密钥更新方案,通过限制新密钥中的明文信息量摆脱一次一密的密钥系统。其次,改进了三维循环移位置乱方法,并以此降低明文中的相关性。随后,根据混沌序列动态选取DNA编码规则及编码顺序,并在此基础上将图像矩阵逐像素动态交错编码为DNA序列。最后,将编码后的DNA序列与给定序列进行碱基运算完成对明文图像的加密。仿真实验表明,该算法密文图像的相关性可低至10-3,全局信息熵可达7.9994。该算法能抵挡各种攻击方式,具有较高安全性。 展开更多
关键词 图像加密 Lorenz超混沌系统 DNA编码 三维循环移位
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Monitoring slope deformation using a 3-D laser image scanning system: a case study 被引量:10
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作者 YUE Depeng WANG Jiping +2 位作者 ZHOU Jinxing CHEN Xiaoxue REN Huijun 《Mining Science and Technology》 EI CAS 2010年第6期898-903,共6页
An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province. The basic working principles, performance indexes, features and data collection and proce... An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province. The basic working principles, performance indexes, features and data collection and processing methods are illus-trated. The point cloud results are analyzed in detail. The rescale range analysis method was used to analyze the deformation char-acteristics of the slope. The results show that the trend of slope displacement is stable and that the degree of landslide danger is low. This work indicates that 3-D laser image scanning can supply multi-parameter, high precision real time data over long distances. These data can be used to study the distortion of the slope quickly and accurately. 展开更多
关键词 3-D laser image scanning system ILRIS-36D -distortion SLOPE MONITOR
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A new 3-D element formulation on displacement of steel-concrete composite box beam 被引量:2
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作者 周凌宇 余志武 贺桂超 《Journal of Central South University》 SCIE EI CAS 2013年第5期1354-1360,共7页
Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were establi... Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were established. Analytic solutions of combined differential equations were also established. Partial degree of freedom was adopted to establish a new FEA element of three-dimensional beam, taking into account the slip effect. Slip and its first-order derivative were introduced into the nodes of composite box beams as generalized degree of freedom. Stiffness matrix and load array of beam elements were established. A three-dimensional nonlinear calculation program was worked out. The results show that the element is reliable and easy to divide and is suitable for special nonlinear analysis of large-span composite box beams. 展开更多
关键词 steel-concrete composite box beam shear deformation slip effect variational method finite beam element method
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3D Visualization of Landslide Deformation
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作者 ZHANG Kun ZHANG Songlin 《Geo-Spatial Information Science》 2007年第1期67-70,共4页
The deformation of landslide is usually expressed in horizontal and vertical direction separately. Based on the X, Y, Z coor-dinates from a real monitoring project, a method to build three-dimensional(3D) model of lan... The deformation of landslide is usually expressed in horizontal and vertical direction separately. Based on the X, Y, Z coor-dinates from a real monitoring project, a method to build three-dimensional(3D) model of landslide by constructing triangulated ir-regular network (TIN) and extruding contour lines is proposed. The almost imperceptible displacements of monitoring points are zoomed by two kind of exaggerating methods. The deformation process is replayed using 3D animation technique. 展开更多
关键词 LANDSLIDE displacement vector VISUALIZATION rubber-band animation
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A Novel 360°3D Profilometry
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作者 SONG Yuanhe,ZHAO Hong,FAN Hua,CHEN Wenyi,TAN Yushan (Research Institute for Laser & Infrared Applications, Xi’an Jiaotong University,Xi’an 710049,CHN) 《Semiconductor Photonics and Technology》 CAS 1998年第1期45-49,共5页
A new method of 360° turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper.A sine light field is applied in the projected light stripe,meanw... A new method of 360° turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper.A sine light field is applied in the projected light stripe,meanwhile phase shifting technique is used to calculate phase of the light slit.Thereafter wrapped phase distribution of the slit is formed and the unwrapping process will be made by means of the height information based on the light sectioning method.Therefore phase measuring results with better precision can be obtained.At last the target 3D shape data can be produced according to geometric relationships between phases and the object heights.The principles of this method are discussed in detail and experimental results are shown in this paper. 展开更多
关键词 Light Sectioning Phase Shifting Phase Unwrapping Algorithm 3D Shape Measurement
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