A rapid detection method for the surface defects of mosaic ceramic tiles

Due to its unique artistic value, mosaic ceramics are widely used in construction-related fields. To meet the artist's demand for high-quality mosaic ceramic to create artistic works, it is necessary to meet the needs for efficient screening of mosaic ceramic tiles. Different from the ordinary large-target ceramics, mosaic ceramics exhibit characteristics of small tile sizes, a variety of colors, large demand for quantities, and easy reflection on the surface. Common manual detection methods show problems of low efficiency or accuracy, easy to fatigue, and many others. To solve these problems, this paper proposes a new detection method to identify surface defects of mosaic ceramic tiles and designs a detection system platform to achieve rapid detection. The experiment proves that the detection system has a detection rate of 93.99% for small defects on the surface of mosaic ceramic tiles, and the detection time of a single mosaic ceramic tile is less than 0.06 s. The detection method can quickly and accurately screen out high-quality, defect-free mosaic ceramic tiles, which can effectively improve the quality and artistic value of mosaic ceramic art creation.     

Theoretical investigation of intrinsic point defects and the oxygen migration behavior in rare earth hafnates

In this work, the composition-dependent point defect types and formation energies of RE₂Hf₂O₇ (RE = La, Ce, Pr, Nd, Pm, Sm, Eu and Gd) as well as the oxygen diffusion behavior are systematically investigated by first-principles calculations. The possible defect reactions and dominant defect complexes under stoichiometric and non-stoichiometric conditions are revealed. It is found that O Frenkel pairs are the predominant defect in stoichiometric pyrochlore hafnates. Hf-RE cation anti-site defects, accompanied by RE vacancies and/or oxygen interstitials, are stable in the non-stoichiometric case of HfO₂ excess. On the other hand, RE-Hf anti-site defects together with oxygen vacancies and/or RE interstitials are preferable in the case of RE₂O₃ excess. The energy barriers for the migration along the V_O48f - V_O48f pathway of pyrochlore hafnates were calculated to be between 0.81 eV and 0.89 eV. Based on these results, a defect engineering strategy is proposed and the pyrochlore hafnates investigated here are predicted to exhibit potential oxygen ionic conductivity.     

动物源性食品中非法使用药物残留检测方法的研究进展

动物性食品可为人类提供丰富的蛋白质、脂肪、矿物质和维生素,是人类饮食中不可缺少的部分。随着人类生活水平的逐步提高,人们对动物源性食品的安全问题也越来越重视,而非法使用药物残留也一直是重要的影响因素之一。药物残留不仅会给消费者带来潜在危害,残留毒性和耐药性也会对食物和环境有显著影响。故本文综述了当前国内外关于动物源性食品中非法使用药物残留的原因、危害和药物种类,介绍了药物残留的常用检测方法,以期为加大动物源性食品中非法使用药物残留检测的力度和精度,以及从源头控制动物源性食品安全提供一定的理论指导依据。     

CLOI-NET: Class segmentation of industrial facilities’ point cloud datasets

Shape segmentation from point cloud data is a core step of the digital twinning process for industrial facilities. However, it is also a very labor intensive step, which counteracts the perceived value of the resulting model. The state-of-the-art method for automating cylinder detection can detect cylinders with 62% precision and 70% recall, while other shapes must then be segmented manually and shape segmentation is not achieved. This performance is promising, but it is far from drastically eliminating the manual labor cost. We argue that the use of class segmentation deep learning algorithms has the theoretical potential to perform better in terms of per point accuracy and less manual segmentation time needed. However, such algorithms could not be used so far due to the lack of a pre-trained dataset of laser scanned industrial shapes as well as the lack of appropriate geometric features in order to learn these shapes. In this paper, we tackle both problems in three steps. First, we parse the industrial point cloud through a novel class segmentation solution (CLOI-NET) that consists of an optimized PointNET++ based deep learning network and post-processing algorithms that enforce stronger contextual relationships per point. We then allow the user to choose the optimal manual annotation of a test facility by means of active learning to further improve the results. We achieve the first step by clustering points in meaningful spatial 3D windows based on their location. Then, we apply a class segmentation deep network, and output a probability distribution of all label categories per point and improve the predicted labels by enforcing post-processing rules. We finally optimize the results by finding the optimal amount of data to be used for training experiments. We validate our method on the largest richly annotated dataset of the most important to model industrial shapes (CLOI) and yield 82% average accuracy per point, 95.6% average AUC among all classes and estimated 70% labor hour savings in class segmentation. This proves that it is the first to automatically segment industrial point cloud shapes with no prior knowledge at commercially viable performance and is the foundation for efficient industrial shape modeling in cluttered point clouds.     

浅谈城市废水水质检测方法与应用

国家与地区的经济发展水平一定离不开工业的发展,我国作为工业大国,工业发展对于国家整体经济有着不可取代的作用。然而随着工业的发展,全球性的环境污染和生态破坏越来越严重。特别是我国经济正处于快速发展阶段,城市化进程不断推进,城市污染情况日益严重,城市污水治理工作逐渐被大众所关注,逐渐开始进入公众可能给事业。我国二十世纪七十年代开始逐渐开始现代城市污水的治理工作。因此,对城市污水的水质监测工作成为了极为重要的一个环节。从城市污水检测方式这一角度进行研究,分析当前城市污水水质检验方法提升实际效果的应用模式,希望能够更好的处理我国城市日益严峻废水处理问题。     

Evolution of internal cracks and residual stress during deposition of TBC

Thermal barrier coating (TBCs) are ceramic coatings that are deposited on metallic substrates to provide high thermal resistance. Residual stress is among the critical factors that affect the performance of TBCs. It evolves during the process of coating deposition and in-service loading. High residual stresses result in significant cracking and premature delamination of the TBC layer. In the present study, a hybrid computational approach is used to predict the evolution of internal cracks and residual stress in TBC. Smooth particle hydrodynamics (SPH) is first used to model the deposition of yttria-stabilized zirconia (YSZ) layer that contains various interfaces and micropores on a steel substrate. Then, three-dimensional (3D) finite element analysis is utilized to predict the evolution of internal cracks and residual stress in the ceramic coating layer. It is found that multiple cracks emerge during the solidification of the coating layer due to the development of high tensile (quenching) stresses. The cracking density is higher at regions near the coating interface. It is also found that compressive (residual) stresses are developed when the deposited coating is cooled to room temperature. The residual stress state is equibiaxial and nonlinear across the thickness/width of the TBC layer. The residual stress profile predicted compares well with that of hole drilling experiments.     

Affine hull based target representation for visual tracking

Handling appearance variations is a challenging issue in visual tracking. Existing appearance models are usually built upon a linear combination of templates. With such kind of representation, accurate visual tracking is not desirable when heavy appearance variations are in presence. Under the framework of particle filtering, we propose a novel target representation for tracking. Namely, the target candidates are represented by affine combinations of a template set, which leads to better capability in describing unseen target appearances. Additionally, in order to adapt this representation to dynamic contexts across a video sequence, a novel template update scheme is presented. Different from conventional approaches, the scheme considers both the importance of one template to a target candidate in the current frame and the recentness of the template that is kept in the template set. Comprehensive experiments show that the proposed algorithm achieves superior performances in comparison with state-of-the-art works.     

一种矿用二氧化氮传感器的检测方法

矿用二氧化氮传感器是煤矿常用的气体检测仪表，针对煤矿需求开发的矿用二氧化氮传感器，需要满足煤矿矿用产品要求。文章提出一种矿用二氧化氮传感器检测方法，说明矿用二氧化氮传感器需要满足的技术参数，供实验室检测人员借鉴，也为设计制造矿用二氧化氮传感器提供了参考。     

Comparison of the RAPID-B® flow cytometer and the BAX® system for the detection of non-O157 shiga toxin-producing Escherichia coli (STEC) in beef products

The beef industry continues to be interested in reliable rapid detection technologies for shiga toxin-producing Escherichia coli (STEC). Current rapid technologies require several hours of pre-enrichment and additional time on the rapid technology instrument. A flow cytometer-based system (RAPID-B^®) has been shown to improve the turn-around for results with a more rapid pre-enrichment requiring only 6.5 h pre-enrichment for a 25 g and 8.5 h for a 375 g sample, followed by an additional 30 min time to achieve final results using the screening technology. The purpose of this study was to validate the RAPID-B^® technology for non-O157 STEC detection as compared to the USDA-FSIS reference method which utilizes the BAX^® system. A total of 180 STEC isolates from various sources and 20 non-STEC strains were used to evaluate specificity and sensitivity using the RAPID-B^® flow cytometer. Also, three different weights (25, 325 and 375 g) of beef trim and ground beef samples were spiked with each STEC to verify detection sensitivity of BAX^® system and RAPID-B^® flow cytometer. For both methods, samples were confirmed by culturing using the USDA-FSIS reference method regardless of the screening result. The RAPID-B^® flow cytometer showed that 180 isolates were all positive and the 20 non-STEC strains were all negative. For spiked beef samples, overall detection sensitivity was the same for both the BAX^® system and RAPID-B^® flow cytometer. When detection sensitivity was based on sample weight, there was no differences in 25 and 375 g samples between RAPID-B^® flow cytometer and USDA-FSIS reference method. The RAPID-B^® system yielded the same sensitivity as the reference method with a decrease of over 10 h of pre-enrichment time and 3 h of rapid screening detection time. In conclusion, the RAPID-B^® flow cytometer based on whole cell detection generated similar results as BAX^® system therefore the RAPID-B^® flow cytometer system could be a valuable rapid method for the detection of non-O157 STEC in beef products.     

外墙保温系统中粘结材料的检测技术分析

选择了几份典型的外墙外保温系统标准,通过对这几份标准中胶粘剂和抹面胶浆的成型和检测方法的比较,分析了现有检测技术的优劣,并结合工作实践提出了建议。