Three-dimensional finite element simulation and reconstruction of jointed rock models using CT scanning and photogrammetry

The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.

An integrated rice panicle phenotyping method based on X-ray and RGB scanning and deep learning

Rice panicle phenotyping is required in rice breeding for high yield and grain quality.To fully evaluate spikelet and kernel traits without threshing and hulling,using X-ray and RGB scanning,we developed an integrated rice panicle phenotyping system and a corresponding image analysis pipeline.We compared five methods of counting spikelets and found that Faster R-CNN achieved high accuracy(R~2 of 0.99)and speed.Faster R-CNN was also applied to indica and japonica classification and achieved 91%accuracy.The proposed integrated panicle phenotyping method offers benefit for rice functional genetics and breeding.

微焦点X射线成像扫描控制与数据获取系统

文章介绍了微焦点X射线成像扫描控制与数据获取系统的原理、软硬件结构以及实现技术。该系统通过串口通讯协议,实现了实时图像采集的手动扫描控制、自定义扫描轨迹的自动控制,通过图像采集卡采集和存储微焦点X射线图像,为微焦点成像分析处理的研究提供了良好的实验平台。

扫描式X射线成像器在锅炉生产行业中的应用

目前,锅炉生产行业的绝大多数企业都使用X射线电视实时成像系统检测小口径管子对接环焊缝。作为大批量管子焊接质量检测的有效手段,该方法在生产中具有不可替代的作用。但X射线电视实时成像系统采用图像增强器作为射线接收装置,具有体积大、射线转化效率低、易老化、图像噪声大、灵敏度低及设备使用成本高等弊端。成功开发了扫描式X射线成像器和动态图像处理系统,有效解决了上述难题。介绍了扫描式X射线成像器和动态图像处理系统的技术特点,并对扫描式X射线成像器与图像增强器进行了对比,分析了扫描式X射线成像器在锅炉生产行业应用的经济性。

图像增强器式线阵列X射线数字成像系统

针对现有线阵列X射线数字成像技术的设计原理和存在的不足,利用图像增强器和图像传感器的最新技术成果,研制成功新型线扫描成像系统。该系统在检测速度为6m/min的条件下,最高分辨率可达10.0Lp/mm,IQI灵敏度1.25～1.60%,图像质量满足JB/T4730—2005标准AB级要求。系统可广泛应用于锅炉压力容器和压力管道焊缝及铸造零件的内部缺陷检测。

X-ray imaging of atomic nuclei

Optically imaging atomic nuclei is a long-sought goal for scientific and applied research,but it has never been realized so far.We integrate aberration-corrected scanning transmission electron microscopy(STEM),the bremsstrahlung generation of X-ray photons,and the energy-dispersive X-ray spectroscopic(EDS)receiving and mapping of the photons into a new microscopy method of optical imaging,by which atomic nuclei of different materials are successfully imaged with X-ray photons.Moreover,this imaging method is shown to be workable with different STEM instruments and be capable of distinguishing atomic nuclei of different elements and resolving imaged size differences of atomic nuclei with the order of magnitude as small as 1 pm.Therefore,it is a general method that can image atomic nuclei and their evolutions in materials science,chemistry and physics.

Malignant giant cell tumor in the left upper arm soft tissue of an adolescent:A case report

BACKGROUND Giant cell tumor of soft tissue(GCT-ST)is an extremely rare low-grade soft tissue tumor that is originates in superficial tissue and rarely spreads deeper.GCT-ST has unpredictable behavior.It is mainly benign,but may sometimes become aggressive and potentially increase in size within a short period of time.CASE SUMMARY A 17-year-old man was suspected of having a fracture,based on radiography following left shoulder trauma.One month later,the swelling of the left shoulder continued to increase and the pain was obvious.Computed tomography(CT)revealed a soft tissue mass with strip-like calcifications in the left shoulder.The mass invaded the adjacent humerus and showed an insect-like area of destruction at the edge of the cortical bone of the upper humerus.The marrow cavity of the upper humerus was enlarged,and a soft tissue density was seen in the medullary cavity.Thoracic CT revealed multiple small nodules beneath the pleura of both lungs.A bone scan demonstrated increased activity in the left shoulder joint and proximal humerus.The mass showed mixed moderate hypointensity and hyperintensity on T1-weighted images,and mixed hyperintensity on T2-weighted fat-saturated images.The final diagnosis of GCT-ST was confirmed by pathology.CONCLUSION GCT-STs should be considered in the differential diagnosis of soft tissue tumors and monitored for large increases in size.