Determination of geological strength index of jointed rock mass based on image processing

The geological strength index(GSI) system,widely used for the design and practice of mining process,is a unique rock mass classification system related to the rock mass strength and deformation parameters based on the generalized Hoek-Brown and Mohr-Coulomb failure criteria.The GSI can be estimated using standard chart and field observations of rock mass blockiness and discontinuity surface conditions.The GSI value gives a numerical representation of the overall geotechnical quality of the rock mass.In this study,we propose a method to determine the GSI quantitatively using photographic images of in situ jointed rock mass with image processing technology,fractal theory and artificial neural network(ANN).We employ the GSI system to characterize the jointed rock mass around the working in a coal mine.The relative error between the proposed value and the given value in the GSI chart is less than 3.6%.

CHANNEL ERROR CORRECTION FOR WIDEBAND SAR-A JOINT MULTIPLE SUBPULSES PROCESSING METHOD

A novel method,referred to as joint multiple subpulses processing,is developed to calibrate the nonideal transfer function of radio frequency front-end and I/Q imbalance in quadrature modulate/demodulate systems simultaneously,which frequently occur in wideband Synthetic Aperture Radar(SAR) systems.Based on the time-frequency relation of the chirp signal and the analyses of the channel errors in wideband SAR,joint multiple subpulses processing method is adopted to separate the image frequency component due to the I/Q channel error.Then,the complete description of the channel error is acquired for building the correction function,which is used to correct the radar raw echo in frequency domain.The validity and capability of this method are demonstrated by the experiments of the channel error correction on the high resolution SAR system with the effective bandwidth of 500 MHz.

Management and classification of the fracture of lateral process of talus:An overview and literature update

Fracture of the lateral process of the talus(FLPT)is uncommon in clinical practice and can be easily missed or misdiagnosed.In recent years,as researchers from all over the world have further deepened their research on FLPT,there has been a breakthrough in the classification,and the methods and principles of clinical management have changed accordingly;however,there is still no standardized guideline for the diagnosis and management of FLPT,and there have been few relevant literature review articles related to this kind of fracture in the past at least 5 years.In this article,we review the clinical classification,classification-based therapeutic recommendations,and prognosis of FLPT,with the aim of providing a reference for the clinical diagnosis and management of this infrequent fracture.

The joint Laplace transforms for killed diffusion occupation times

The approach of Li and Zhou(2014)is adopted to find the Laplace transform of occupation time over interval(0,a)and joint occupation times over semi-infinite intervals(-∞,a)and(b,∞)for a time-homogeneous diffusion process up to an independent exponential time e_(q)for 0<a<b.The results are expressed in terms of solutions to the differential equations associated with the diffusion generator.Applying these results,we obtain explicit expressions on the Laplace transform of occupation time and joint occupation time for Brownian motion with drift.

Unstable evolution of railway slope under the rainfall-vibration joint action

Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains.However,as two major factors affecting the stability of railway slopes,few scholars have explored the unstable evolution of railway slopes under the joint action of rainfall-vibration.Based on the model test of sandy soil slope,the unstable evolution process of slope under locomotive vibration,rainfall,and rainfall-vibration joint action conditions was simulated in this paper.By comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions,the change laws of pore pressure under the influence of vibration and rainfall were explored.The main control factors affecting the stability of slope structure under the joint action conditions were further defined.Combined with the slope failure phenomena under these three conditions,the causes of slope instability resulting from each leading factor were clarified.Finally,according to the above conclusions,the unstable evolution of the slope under the rainfall-vibration joint action was determined.The test results show that the unstable evolution process of sandy soil slope,under the rainfall-vibration joint action,can be divided into:rainfall erosion cracking,vibration promotion penetrating,and slope instability sliding three stages.In the process of slope unstable evolution,rainfall and vibration play the roles of inducing and promoting slide respectively.In addition,the deep cracks,which are the premise for the formation of the sliding surface,and the violent irregular fluctuation of soil pressure,which reflects the near penetration of the sliding surface,constitute the instability characteristics of the railway slope together.This paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfall-vibration,hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.

Use of Image processing software in Hip Joint surgery

The scope of this project was to investigate the possibility of application of Image Processing Technique in the field of Shaft Alignment process. Misalignment of shaft using image processing software Visionbuilder was calculated. The further purpose of this project was to check whether the image processing technique can be used in bone transplant surgery. The model of the hip was used for the experimentation purpose. Image processing software Visionbuilder was used to match the profiles of the bone before implant and bone after implant.

Microstructures and microhardness for sheets and TIG welded joints of TA15 alloy using friction stir spot processing

Effects of friction stir spot processing(FSSP)on the microstructures and microhardness of tungsten inert gas(TIG)welded TA15titanium alloy joints were investigated.The macro/micro structural observation and microhardness evaluation of the TA15alloy sheets and TA15TIG welded joints were carried out using optical microscope and microhardness tests.The results show that FSSP effectively improves the microstructure and increases the microhardness of the TA15sheets.As for the TIG welded joints,FSSP also effectively improves the microstructure of joints.And the average microhardness value in weld nugget zone is improved significantly,while a small increase of this value in heat affected zone is observed.The hardness in stirring zone is significantly higher than that in the base metal.Two peak values of hardness appear along the width direction in stirring zone.After FSSP,the average hardness of the weld zone of TA15TIG welded joint is significantly higher than that before FSSP.Under the present process parameters,both the surface oxidation in TA15sheets and in TIG welded joints after FSSP are not evident,while the surface forms the bright white layer,which is composed of a great multitude of fine grains.

Laser Shock Processing of Metal Sheet and Welded Joints

In order to study the application of laser shock processing(LSP) as a post weld treatment technology and a strengthening technology, a series experiments and analysis were taken in this paper. The hardness of the laser shock processed zone of Al-Li alloy was measured, and the microstructure and mechanical properties of the welded joints of the Ni-based superalloy GH30 and the Austenitic stainless steel !Crl8Ni9Ti were compared with those without LSP in this paper. The results showed that the size of strengthened zone was similar to that of laser spot and strengthened layer was about 1mm deep, and the high intense dislocations and twins produced in the shocked zone. Plastic strain also gained surface residual compress stress, which is benefit for the fatigue properties of welded zones. In this test , the surface hardness of welding zone of the superalloy GH30 improved obviously and tensile strength increased by 12%, but the improvement of fatigue life was not obvious; Martensite phase is formed in plasma welding !Crl8Ni9Ti, which reduced the effect of strain deformation martensite induced by laser shock processing, but the surface residual compress stress gained by laser shock processing can obviously improve the fatigue life of !Crl8Ni9Ti welded joints.

Rupture process of the 2011 Tohoku earthquake from the joint inversion of teleseismic and GPS data

Teleseismic and GPS data were jointly inverted for the rupture process of the 2011 Tohoku earthquake. The inversion results show that it is a bilateral rupture event with an average rupture velocity less than 2.0 km/s along the fault strike direction. The source rupture process consists of three sub-events, the first oc- curred near the hypocenter and the rest two ruptured along the up-dip direction and broke the sea bed, causing a maximum slip of about 30 m. The large-scale sea bed breakage may account for the tremendous tsunami disaster which resulted in most of the death and missing in this mega earthquake.

Endoscopic joint capsule and articular process excision to treat lumbar facet joint syndrome:A case report

BACKGROUND Lumbar facet joint syndrome(LFJS)is a pain condition arising from lumbar facet joint diseases.Treatments of LFJS includes patient education,oral medication,bed rest,physical therapy,and procedural interventions.For some refractory cases that fail conservative therapies,dorsal ramus medial brunch radiofrequency ablation is warranted.However,as nerve fibers can regenerate,their efficacy is impermanent,and the recurrence rate is relatively high.Considering synovial impingement is a paramount pathogenesis of LFJS,in this case,we removed the culprit hyperplastic articular capsule and the articular process partially through a spinal endoscope.As the culprit hyperplastic joint capsule was excised,it is supposed to generate more prolonged efficacy and a lower recurrence rate than radiofrequency treatment.CASE SUMMARY A 40-year-old female patient was diagnosed with LFJS.She complained of low back pain and right buttock pain for half a year.The patient was placed in the prone position.After disinfection and draping,a 25-cm 18-gauge needle was inserted into the dorsal surface of the right L5 articular process.Subsequently,a guidewire,dilating tubes,and a working cannula was inserted successively.The spinal endoscope was positioned in the working cannula.Under the endoscope,the microvascular tissue,muscle tissue attached on the L5 inferior articular process and S1 superior articular process,as well as the capsule and minor portion of the inferior articular process were removed.After the joint space was clear and no bleeding points existed,the endoscope and working cannula were shifted,and the incision was sutured.After treatment,the symptoms were completely relieved.The patient was pain-free during the follow-up period of 6 mo.CONCLUSION The endoscopic partial joint capsule and articular process excision is an effective procedure for LFJS,especially for cases caused by synovial impingement.

Equivalence of Uniqueness in Law and Joint Uniqueness in Law for SDEs Driven by Poisson Processes

We give an extension result of Watanabe’s characterization for 2-dimensional Poisson processes. By using this result, the equivalence of uniqueness in law and joint uniqueness in law is proved for one-dimensional stochastic differential equations driven by Poisson processes. After that, we give a simplified Engelbert theorem for the stochastic differential equations of this type.

Estimation of the 2010 Mentawai tsunami earthquake rupture process from joint inversion of teleseismic and strong ground motion data

Joint inversion of teleseismic body-wave data and strong ground motion waveforms was applied to determine the rupture process of the 2010 Mentawai earthquake. To obtain stable solutions, smoothing and non-negative constraints were introduced. A total of 33 teleseismic stations and 5 strong ground motion stations supplied data. The teleseismic and strong ground motion data were separately windowed for 150 s and 250 s and bandpass filtered with frequencies of 0.001e1.0 Hz and 0.005e0.5 Hz, respectively. The finitefault model was established with length and width of 190 km and 70 km, and the initial seismic source parameters were set by referring to centroid moment tensor(CMT) solutions. Joint inversion results indicate that the focal mechanism of this earthquake is thrust fault type, and the strike, dip, and rake angles are generally in accordance with CMT results. The seismic moment was determined as 5.814 1020Nm(Mw7.8) and source duration was about 102 s, which is greater than those of other earthquakes of similar magnitude. The rupture nucleated near the hypocenter and then propagated along the strike direction to the northwest, with a maximum slip of 3.9 m. Large uncertainties regarding the amount of slip retrieved using different inversion methods still exist; however, the conclusion that the majority of slip occurred far from the islands at very shallow depths was found to be robust. The 2010 Mentawai earthquake was categorized as a tsunami earthquake because of the long rupture duration and the generation of a tsunami much larger than was expected for an earthquake of its magnitude.

Rupture process of the January 8, 2022, Menyuan M 6.9 earthquake

After the occurrence of destructively strong earthquakes, rapid acquisition of the source rupture process can provide important reference information for post-earthquake disaster relief and aftershock trend determination.An M 6.9 earthquake occurred in Menyuan County, Qinghai Province on January 8, 2022. The epicenter is located in the seismic gap in the middle section of the Haiyuan fault belt. Such a typical strong earthquake was taken as an example to investigate the rupture process of strong earthquakes. Three days after the earthquake, the InSAR(Interferometric Synthetic Aperture Radar) coseismic deformation field was obtained by Sentinel radar, indicating that the surface ruptured obviously. The southern block of the earthquake faces towards the satellite about 95 cm along the LOS(line of sight) direction, and the northern block is away from the satellite by ~ 74 cm, consistent with the characteristic of left-lateral strike-slip motion. In this study, InSAR coseismic deformation data and farfield waveform data were used to jointly invert the earthquake rupture process, and a four-segment finite fault model was constructed by referring to the surface deformation. The inversion results show that the focal depth of the Menyuan earthquake is about 7 km, and the strike of the seismogenic fault is 89.0°, 104.0°, 119.0°and 131.0°from west to east, respectively. It is a high-dip left-lateral strike-slip earthquake event lasting about 14 s. The rupture propagation mode is a bilateral extension. The maximum slip along the fault is about 380 cm, and the seismic moment magnitude is 6.7. The surface rupture length is about 24 km, which is consistent with that measured in the field survey. The detailed seismic source model can provide basic data for the aftershock trend determination and seismic risk analysis of the adjacent active faults.

基于ABB机器人与Process Simulate间的虚实联调研究

无论高等院校的师生还是智能工厂的数字化工程师,在利用软件Process Simulate完成机器人工作站的虚实联调时往往会消耗大量的时间,结果还不理想,因为其用到的方法是传统的创建多个机器人子程序,或是创建一个机器人程序在程序中用到大量的等待信号去完成物理属性的机器人工作站与软件内机器人工作站的数字孪生同步运行,此方法能够实现物理属性的机器人工作站与软件内机器人工作站的同步运行即虚实联调,但是效率低同时对项目实施者要求也非常高,因此利用传统的方法完成机器人工作站的虚实联调会困难重重,效果还不理想。为了节省数字孪生项目中机器人工作站与软件间的虚实联调的完成时间和降低项目完成难度,作者通过在数字孪生实验室的大量实验研究,最终通过在真实机器人控制器中编写机器人程序读取机器人各轴位置数据,借助Profinet通讯完成机器人与PS软件间的实时位置数据交互,进而较快地完成虚实联调项目。通过与传统的方法做对比测试,作者创建的方法使项目完成的效率得到显著提高,同时降低了项目完成难度。基于以上对比测试,作者研究的方法在以后数字孪生项目中会得到很好地推广,并慢慢会取代传统的方法。

基于CenterNet的跑步姿态鉴别系统的设计

为了改善目前大众跑步姿势普遍不规范的现状,提出了一种基于CenterNet的跑步姿态鉴别系统。首先,通过截图、拍照的方式自制数据集,并对数据集进行清洗、标注和分析,消除数据无关信息与简化数据。其次,引入多尺度通道注意力机制与添加十字星变形卷积2种方式改进CenterNet算法模型,将动作图像转化为数字信息和特征向量,并以此为基础,利用KNN(K-nearest neighbors)算法对跑步姿态类型进行分类。最后,与经典模型方案进行对比,验证改进CenterNet算法鉴别系统的有效性。结果表明:改进的CenterNet模型的精确率与召回率都有所提升,其参数量与计算量降低。所提算法模型能够对大多数不良姿势作出及时、准确反馈,有效帮助跑步爱好者发现问题,从而改善跑步姿态、提高运动效率、预防伤病。

焊接工艺参数对旋转摩擦焊铝-铜接头弯曲性能的影响

对1070纯铝和T2纯铜进行了旋转摩擦焊接。研究了摩擦焊工艺参数对铝-铜接头弯曲性能的影响。采用电子探针显微分析仪检测了铝-铜接头界面的微观形貌和元素分布。结果表明:较短时间(2 s)摩擦焊制备的铝-铜接头(1号试样)弯曲试验时断裂于铝-铜界面,为脆性断裂,随着摩擦时间的增加,铝-铜接头弯曲试验时断裂于铝侧,为韧性断裂;以2~5 s的摩擦时间制备的铝-铜接头界面均未发现有明显的金属间化合物,但发生了成分变化;较短时间摩擦焊制备的1号试样成分变化区宽约1.6μm,较长时间(5 s)摩擦焊制备的4号试样成分变化区宽约2.7μm;较宽的成分变化区能提高铝-铜接头界面的结合强度,从而提高铝-铜接头的弯曲性能,较窄的成分变化区是弯曲试验过程中铝-铜接头界面断裂的主要原因。

压力管道建造过程中焊接接头射线检测标准比较与分析

压力管道按属性和用途分类,可分为工业、公用及长输管道,其焊接接头射线检测执行标准涉及NB/T 47013.2,GB/T 12605及SY/T 4109,此三项标准在检测适用性、检测工艺及检测质量分级等方面存在一定区别,系统比较并分析了其相关特点和差异,为从事压力管道设计、施工、检测及建造监督的相关人员提供参考,尤其建议设计和业主者应对上述标准进行综合选用。

基于响应面法的铝合金角接激光焊工艺优化

文章选用板材厚度为2 mm的5754铝合金,采用角接的搭接形式,开展激光熔焊焊接试验。以激光功率P、焊接速度v、离焦量Z为试验参数,以焊接接头的最大拉力F为响应指标,建立响应面分析的数学模型。研究结果表明:激光功率、焊接速度、离焦量对最大拉力均有明显影响。激光功率越大、焊接速度和离焦量越小,最大拉力越大。分析所建立的数学模型,确定较优工艺区间,结合焊缝成形的宏观形貌,获取最优工艺参数组合。最大拉力相比于试验组中的最优组提升5.55%。

“双一流”建设下的多专业联合毕业设计教学模式研究

通过多元化教学模式,积极探索“双一流”学科内部各专业联合毕业设计模式和全过程标准化设计管理,对于全面提升学科建设水平和实现“双一流”建设培养一流人才的目标具有重要意义。分析国内联合毕业设计教学模式,探讨北京工业大学城市建设学部多专业联合毕业设计的可行性。基于学科交叉与专业融合,提出了多专业联合毕业设计的教学目标,通过基于混合教学的多专业联合毕业设计教学实践,提出教学方法、设计选题题库、资源的整合与共享、质量控制、组织形式和教学评估反馈等具体实施细节。

基于快速联合双边滤波器和改进PCNN的红外与可见光图像融合

针对红外与可见光图像融合结果中细节丢失、目标不显著和对比度低等问题,提出了一种结合快速联合双边滤波器(fast joint bilateral filter,FJBF)和改进脉冲耦合神经网络(pulse coupled neural network,PCNN)的红外与可见光图像融合方法,在保证融合图像质量的前提下有效提高运行效率。首先,利用快速联合双边滤波器对源图像进行分解;其次,为了更好地提取图像中显著结构和目标信息,针对基础层图像采用一种基于视觉显著图(visual significance map,VSM)的加权平均融合规则,针对细节层图像采用改进脉冲耦合神经网络模型进行融合,其中PCNN的所有参数都可以根据输入波段自适应调节;最后,将基础层融合图与细节层融合图叠加重构得到融合图像。实验结果表明,该方法提高了融合图像的效果,有效地保留了目标、背景细节和边缘等重要信息。