Random fatigue of welded K-type tubular joints subjected to axial or out-of-plane bending load is analyzed. By considering the sizes of initial surface cracks and material constants as random variables with some proba...Random fatigue of welded K-type tubular joints subjected to axial or out-of-plane bending load is analyzed. By considering the sizes of initial surface cracks and material constants as random variables with some probabilistic distributions, incorporating the effect of the weld, five hundred random samples are generated. Statistical computational results of life of crack propagation and effect of change of crack shape are finally obtained and compared with experimental data available based on a regression analysis. Meanwhile, crack propagation behaviors are also investigated.展开更多
A modified discontinuous deformation analysis (DDA) algorithm was proposed to simulate the failure behavior of jointed rock. In the proposed algorithm, by using the Monte-Carlo technique, random joint network was gene...A modified discontinuous deformation analysis (DDA) algorithm was proposed to simulate the failure behavior of jointed rock. In the proposed algorithm, by using the Monte-Carlo technique, random joint network was generated in the domain of interest. Based on the joint network, the triangular DDA block system was automatically generated by adopting the advanced front method. In the process of generating blocks, numerous artificial joints came into being, and once the stress states at some artificial joints satisfy the failure criterion given beforehand, artificial joints will turn into real joints. In this way, the whole fragmentation process of rock mass can be replicated. The algorithm logic was described in detail, and several numerical examples were carried out to obtain some insight into the failure behavior of rock mass containing random joints. From the numerical results, it can be found that the crack initiates from the crack tip, the growth direction of the crack depends upon the loading and constraint conditions, and the proposed method can reproduce some complicated phenomena in the whole process of rock failure.展开更多
A second order oscillator with nonlinear restoring force and nonlinear damping is considered: it is subject to both external and internal (parametric) excitations of Gaussian white noise type. The nonlinearities are c...A second order oscillator with nonlinear restoring force and nonlinear damping is considered: it is subject to both external and internal (parametric) excitations of Gaussian white noise type. The nonlinearities are chosen in such a way that the associated Fokker-Planck-Kolmogorov equation is solvable in the steady state. Different choices of some system parameters give rise to different and interesting shapes of the joint probability density function of the response, which in some cases appears to be multimodal. The problem of the determination of the power spectral density of the response is also addressed by using the true statistical linearization method.展开更多
An innovative inversion code, named “Curupira v1.0”, has been developed using Matlab to determine the vertical distribution of resistivity beneath the subsoil. The program integrates Vertical Electrical Sounding (VE...An innovative inversion code, named “Curupira v1.0”, has been developed using Matlab to determine the vertical distribution of resistivity beneath the subsoil. The program integrates Vertical Electrical Sounding (VES), successful in shallow subsurface exploration and Time Domain Electromagnetic (TEM) techniques, better suited for deeper exploration, both of which are widely employed in geophysical exploration. These methodologies involve calculating subsurface resistivity through appropriate inversion processes. To address the ill-posed nature of inverse problems in geophysics, a joint inversion scheme combining VES and TEM data has been incorporated into Curupira v1.0. The software has been tested on both synthetic and real-world data, the latter of which was acquired from the Parana sedimentary basin which we summarise here. The results indicate that the joint inversion of VES and TEM techniques offers improved recovery of simulated models and demonstrates significant potential for hydrogeological studies.展开更多
In this paper, we are proposing a compression-based multiple color target detection for practical near real-time optical pattern recognition applications. By reducing the size of the color images to its utmost compres...In this paper, we are proposing a compression-based multiple color target detection for practical near real-time optical pattern recognition applications. By reducing the size of the color images to its utmost compression, the speed and the storage of the system are greatly increased. We have used the powerful Fringe-adjusted joint transform correlation technique to successfully detect compression-based multiple targets in colored images. The colored image is decomposed into three fundamental color components images (Red, Green, Blue) and they are separately processed by three-channel correlators. The outputs of the three channels are then combined into a single correlation output. To eliminate the false alarms and zero-order terms due to multiple desired and undesired targets in a scene, we have used the reference shifted phase-encoded and the reference phase-encoded techniques. The performance of the proposed compression-based technique is assessed through many computer simulation tests for images polluted by strong additive Gaussian and Salt & Pepper noises as well as reference occluded images. The robustness of the scheme is demonstrated for severely compressed images (up to 94% ratio), strong noise densities (up to 0.5), and large reference occlusion images (up to 75%).展开更多
目的:探讨火龙罐联合距下关节制动术治疗柔性平足症合并跟腱挛缩的临床疗效和安全性。方法:将2023年7月至2025年2月收治的72例柔性平足症合并跟腱挛缩患者随机分为2组,每组36例,分别采用火龙罐联合距下关节制动术治疗(火龙罐组)和跟腱...目的:探讨火龙罐联合距下关节制动术治疗柔性平足症合并跟腱挛缩的临床疗效和安全性。方法:将2023年7月至2025年2月收治的72例柔性平足症合并跟腱挛缩患者随机分为2组,每组36例,分别采用火龙罐联合距下关节制动术治疗(火龙罐组)和跟腱松解术联合距下关节制动术治疗(跟腱松解组)。火龙罐组在距下关节制动术后第1天开始火龙罐治疗,每次治疗35 min,隔天治疗1次,7 d为1个疗程,共4个疗程。分别于术前及术后3个月、6个月、12个月,记录并比较2组患者的足踝部疼痛视觉模拟量表(visual analogue scale,VAS)评分、美国足与踝关节协会(American Orthopedic Foot and Ankle Society,AOFAS)踝与后足评分及简明健康状况调查表(short form 36 health survey questionnaire,SF-36)评分;分别于术前及术后12个月,测量并比较2组患者的跟骨倾斜角、距骨-第1跖骨角、距舟覆盖角、踝关节外翻角度、踝关节背伸活动度、踝关节背伸峰值力矩、步态时间、步长及双支撑期;观察并比较2组患者的并发症发生情况。结果:①足踝部疼痛VAS评分。2组足踝部疼痛VAS评分随时间变化均呈下降趋势(F=995.560,P=0.000;F=873.277,P=0.000);术后3个月、6个月,火龙罐组足踝部疼痛VAS评分均低于跟腱松解组(t=-9.917,P=0.000;t=-6.609,P=0.000)。②AOFAS踝与后足评分。手术前后AOFAS踝与后足评分总体随时间呈上升趋势(F=846.986,P=0.000);火龙罐组AOFAS踝与后足评分高于跟腱松解组(F=8.378,P=0.004)。③SF-36评分。2组SF-36评分随时间变化均呈上升趋势(F=398.198,P=0.000;F=372.795,P=0.000);术后3个月,火龙罐组SF-36评分高于跟腱松解组(t=12.401,P=0.000)。④影像学指标。术后12个月,2组跟骨倾斜角均大于术前(t=-38.292,P=0.000;t=-32.414,P=0.000),距骨-第1跖骨角及距舟覆盖角均小于术前(t=-41.976,P=0.000;t=-30.378,P=0.000;t=-18.481,P=0.000;t=-12.777,P=0.000),火龙罐组跟骨倾斜角大于跟腱松解组(t=2.588,P=0.012)、距骨-第1跖骨角及距舟覆盖角均小于跟腱松解组(t=-6.128,P=0.000;t=-3.115,P=0.002)。⑤生物力学参数。术后12个月,2组踝关节外翻角度均小于术前(t=8.642,P=0.000;t=4.890,P=0.000),踝关节背伸活动度均大于术前(t=-6.372,P=0.000;t=-13.711,P=0.000),步长均大于术前(t=-50.300,P=0.000;t=-41.169,P=0.000),双支撑期均短于术前(t=17.482,P=0.000;t=4.808,P=0.000);火龙罐组踝关节背伸峰值力矩小于术前(t=71.900,P=0.000),跟腱松解组背伸峰值力矩与术前的差异无统计学意义(t=0.058,P=0.954);火龙罐组步态时间短于术前(t=8.110,P=0.000),跟腱松解组步态时间长于术前(t=-12.161,P=0.000);火龙罐组踝关节外翻角度和踝关节背伸活动度均小于跟腱松解组(t=-1.346,P=0.043;t=-4.853,P=0.000),步长大于跟腱松解组(t=1.503,P=0.014),双支撑期短于跟腱松解组(t=-1.795,P=0.016),踝关节背伸峰值力矩和步态时间与跟腱松解组的组间差异均无统计学意义(t=-4.302,P=0.284;t=-0.158,P=0.907)。⑥安全性。2组患者的并发症发生率比较,差异无统计学意义(χ^(2)=0.633,P=0.426)。结论:火龙罐联合距下关节制动术治疗柔性平足症合并跟腱挛缩,可有效矫正足部畸形、缓解足踝部疼痛、改善步态和足踝部功能、提高患者生活质量,疗效优于跟腱松解术联合距下关节制动术,但在增加踝关节背伸活动度方面疗效不及跟腱松解术联合距下关节制动术,二者在恢复患者基本步行功能、消除足踝部异常生物力学负荷及安全性方面相当。展开更多
文摘Random fatigue of welded K-type tubular joints subjected to axial or out-of-plane bending load is analyzed. By considering the sizes of initial surface cracks and material constants as random variables with some probabilistic distributions, incorporating the effect of the weld, five hundred random samples are generated. Statistical computational results of life of crack propagation and effect of change of crack shape are finally obtained and compared with experimental data available based on a regression analysis. Meanwhile, crack propagation behaviors are also investigated.
基金Projects(50479071, 40672191) supported by the National Natural Science Foundation of ChinaProject(SKLZ0801) supported by the Independent Research Key Project of State Key Laboratory of Geomechanics and Geotechnical EngineeringProject(SKLQ001) supported by the Independent Research Frontier Exploring Project of State Key Laboratory of Geomechanics and Geotechnical Engineering
文摘A modified discontinuous deformation analysis (DDA) algorithm was proposed to simulate the failure behavior of jointed rock. In the proposed algorithm, by using the Monte-Carlo technique, random joint network was generated in the domain of interest. Based on the joint network, the triangular DDA block system was automatically generated by adopting the advanced front method. In the process of generating blocks, numerous artificial joints came into being, and once the stress states at some artificial joints satisfy the failure criterion given beforehand, artificial joints will turn into real joints. In this way, the whole fragmentation process of rock mass can be replicated. The algorithm logic was described in detail, and several numerical examples were carried out to obtain some insight into the failure behavior of rock mass containing random joints. From the numerical results, it can be found that the crack initiates from the crack tip, the growth direction of the crack depends upon the loading and constraint conditions, and the proposed method can reproduce some complicated phenomena in the whole process of rock failure.
文摘A second order oscillator with nonlinear restoring force and nonlinear damping is considered: it is subject to both external and internal (parametric) excitations of Gaussian white noise type. The nonlinearities are chosen in such a way that the associated Fokker-Planck-Kolmogorov equation is solvable in the steady state. Different choices of some system parameters give rise to different and interesting shapes of the joint probability density function of the response, which in some cases appears to be multimodal. The problem of the determination of the power spectral density of the response is also addressed by using the true statistical linearization method.
文摘An innovative inversion code, named “Curupira v1.0”, has been developed using Matlab to determine the vertical distribution of resistivity beneath the subsoil. The program integrates Vertical Electrical Sounding (VES), successful in shallow subsurface exploration and Time Domain Electromagnetic (TEM) techniques, better suited for deeper exploration, both of which are widely employed in geophysical exploration. These methodologies involve calculating subsurface resistivity through appropriate inversion processes. To address the ill-posed nature of inverse problems in geophysics, a joint inversion scheme combining VES and TEM data has been incorporated into Curupira v1.0. The software has been tested on both synthetic and real-world data, the latter of which was acquired from the Parana sedimentary basin which we summarise here. The results indicate that the joint inversion of VES and TEM techniques offers improved recovery of simulated models and demonstrates significant potential for hydrogeological studies.
文摘In this paper, we are proposing a compression-based multiple color target detection for practical near real-time optical pattern recognition applications. By reducing the size of the color images to its utmost compression, the speed and the storage of the system are greatly increased. We have used the powerful Fringe-adjusted joint transform correlation technique to successfully detect compression-based multiple targets in colored images. The colored image is decomposed into three fundamental color components images (Red, Green, Blue) and they are separately processed by three-channel correlators. The outputs of the three channels are then combined into a single correlation output. To eliminate the false alarms and zero-order terms due to multiple desired and undesired targets in a scene, we have used the reference shifted phase-encoded and the reference phase-encoded techniques. The performance of the proposed compression-based technique is assessed through many computer simulation tests for images polluted by strong additive Gaussian and Salt & Pepper noises as well as reference occluded images. The robustness of the scheme is demonstrated for severely compressed images (up to 94% ratio), strong noise densities (up to 0.5), and large reference occlusion images (up to 75%).
文摘目的:探讨火龙罐联合距下关节制动术治疗柔性平足症合并跟腱挛缩的临床疗效和安全性。方法:将2023年7月至2025年2月收治的72例柔性平足症合并跟腱挛缩患者随机分为2组,每组36例,分别采用火龙罐联合距下关节制动术治疗(火龙罐组)和跟腱松解术联合距下关节制动术治疗(跟腱松解组)。火龙罐组在距下关节制动术后第1天开始火龙罐治疗,每次治疗35 min,隔天治疗1次,7 d为1个疗程,共4个疗程。分别于术前及术后3个月、6个月、12个月,记录并比较2组患者的足踝部疼痛视觉模拟量表(visual analogue scale,VAS)评分、美国足与踝关节协会(American Orthopedic Foot and Ankle Society,AOFAS)踝与后足评分及简明健康状况调查表(short form 36 health survey questionnaire,SF-36)评分;分别于术前及术后12个月,测量并比较2组患者的跟骨倾斜角、距骨-第1跖骨角、距舟覆盖角、踝关节外翻角度、踝关节背伸活动度、踝关节背伸峰值力矩、步态时间、步长及双支撑期;观察并比较2组患者的并发症发生情况。结果:①足踝部疼痛VAS评分。2组足踝部疼痛VAS评分随时间变化均呈下降趋势(F=995.560,P=0.000;F=873.277,P=0.000);术后3个月、6个月,火龙罐组足踝部疼痛VAS评分均低于跟腱松解组(t=-9.917,P=0.000;t=-6.609,P=0.000)。②AOFAS踝与后足评分。手术前后AOFAS踝与后足评分总体随时间呈上升趋势(F=846.986,P=0.000);火龙罐组AOFAS踝与后足评分高于跟腱松解组(F=8.378,P=0.004)。③SF-36评分。2组SF-36评分随时间变化均呈上升趋势(F=398.198,P=0.000;F=372.795,P=0.000);术后3个月,火龙罐组SF-36评分高于跟腱松解组(t=12.401,P=0.000)。④影像学指标。术后12个月,2组跟骨倾斜角均大于术前(t=-38.292,P=0.000;t=-32.414,P=0.000),距骨-第1跖骨角及距舟覆盖角均小于术前(t=-41.976,P=0.000;t=-30.378,P=0.000;t=-18.481,P=0.000;t=-12.777,P=0.000),火龙罐组跟骨倾斜角大于跟腱松解组(t=2.588,P=0.012)、距骨-第1跖骨角及距舟覆盖角均小于跟腱松解组(t=-6.128,P=0.000;t=-3.115,P=0.002)。⑤生物力学参数。术后12个月,2组踝关节外翻角度均小于术前(t=8.642,P=0.000;t=4.890,P=0.000),踝关节背伸活动度均大于术前(t=-6.372,P=0.000;t=-13.711,P=0.000),步长均大于术前(t=-50.300,P=0.000;t=-41.169,P=0.000),双支撑期均短于术前(t=17.482,P=0.000;t=4.808,P=0.000);火龙罐组踝关节背伸峰值力矩小于术前(t=71.900,P=0.000),跟腱松解组背伸峰值力矩与术前的差异无统计学意义(t=0.058,P=0.954);火龙罐组步态时间短于术前(t=8.110,P=0.000),跟腱松解组步态时间长于术前(t=-12.161,P=0.000);火龙罐组踝关节外翻角度和踝关节背伸活动度均小于跟腱松解组(t=-1.346,P=0.043;t=-4.853,P=0.000),步长大于跟腱松解组(t=1.503,P=0.014),双支撑期短于跟腱松解组(t=-1.795,P=0.016),踝关节背伸峰值力矩和步态时间与跟腱松解组的组间差异均无统计学意义(t=-4.302,P=0.284;t=-0.158,P=0.907)。⑥安全性。2组患者的并发症发生率比较,差异无统计学意义(χ^(2)=0.633,P=0.426)。结论:火龙罐联合距下关节制动术治疗柔性平足症合并跟腱挛缩,可有效矫正足部畸形、缓解足踝部疼痛、改善步态和足踝部功能、提高患者生活质量,疗效优于跟腱松解术联合距下关节制动术,但在增加踝关节背伸活动度方面疗效不及跟腱松解术联合距下关节制动术,二者在恢复患者基本步行功能、消除足踝部异常生物力学负荷及安全性方面相当。
