2022—2023年阜阳市食品重金属污染情况调查分析

目的:调查分析2022—2023年阜阳市食品风险监测6种食品中Pb、Cd、总Hg、总As、Cr5种重金属污染情况,为食品安全风险监测提供数据支持。方法:采用随机采样的方法,采集阜阳市三区五县农贸市场及各类商超小麦粉、玉米粉、大米、茶叶、黄豆和蔬菜等样品,电感耦合等离子体质谱法检测,对同一重金属元素在不同样品中检出情况及不同重金属元素在相同样品中检出情况进行分析。结果:80份样品中有2份大米样品Pb超标,超标率为2.5%;5种重金属检出率依次为Cr(83.8%)>总As(78.8%)>Cd(61.3%)>Pb(45%)>总Hg(0%);茶叶样品中Cr、Pb最高检出值较高,分别为0.645 mg·kg^(-1)和0.559 mg·kg^(-1),大米样品Pb、Cd、总As最高值分别为0.816 mg·kg^(-1)、0.166 0 mg·kg^(-1)、0.251 0 mg·kg^(-1),存在一定的污染风险;总Hg均未检出,5种重金属检出情况具有统计学差异,χ^(2)=146.323,P<0.001;超标情况无统计学差异,χ^(2)=4.401,P=0.198;结论:2022—2023年监测的80份样品中有2份大米样品Pb超标,且均来自农贸市场样品,应加强农贸市场食品安全监管力度;大米、小麦粉、玉米粉样品Pb(2份超标样品除外)、Cd、总As检出率及最大检出值偏高,虽低于标准限值,但存在一定的污染风险,茶叶中Pb、Cd、总As、Cr检出率均为100%,明显高于黄豆和蔬菜样品,未出现超标样品,总体污染状况良好,食品卫生质量相对安全,但存在污染风险,特别应加强谷物和茶叶重金属的连续监测。

化学分析方法校准曲线有关问题的探讨

校准曲线的线性范围为测定下限与测定上限之间的浓度范围,测定上限应尽可能扩大,但要保证校准曲线呈线性,同时,最高点分析后不会对分析系统造成污染物残留。通常应根据分析方法原理、仪器的特点和样品基质情况来确定校准方式。对于线性校准曲线,除了相关系数外,还要根据不同情况,对校准曲线进行检验。校准曲线的合格判定,除考虑相关系数外,还需要用校准曲线重新计算校准点,对于线性校准,所有校准点计算结果拟合值与实际值的相对误差应在±30%以内,对于非线性二阶校准曲线,应进行最大值与最小值检验。

虚拟仿真融合机器人技术赋能教学模式创新探索

在新工科建设背景下,加快工程教育改革创新,培养创新型卓越工程科技人才。分析了当前智能和自动化专业教学存在的不足,探索并实践了“知践合一、虚实并重、学科融通”的教学新模式。将理论教学与实践教学有机融合,注重学生工程实践能力和创新能力培养,为相关专业工程科技人才培养提供了一种参考的新模式。

生态环境监测全过程病原微生物安全风险识别评估及个体防护

生态环境监测人员在工作中面临病原微生物安全风险。调研发现,已颁布的相关法律法规、标准和规定,多侧重于实验室及医务人员的病原微生物安全防护,缺少生态环境监测人员在采样、样品运输和交接、废弃物处置等过程中的病原微生物安全规范,新冠肺炎疫情期间的防护指导文件比较笼统。笔者在已颁布的法律法规和各项标准基础上,识别和评估生态环境监测全过程病原微生物安全风险,提出相应的监测要求和人员防护建议,针对采样、样品运输和交接、实验室分析和废弃物处置过程提出个人防护措施及突发情况下的应急防护措施。

Pose measurement using quaternion and Kalman filter

In this paper,a method combining perspective-n-point(PnP) and novel iteration algorithm is developed to measure the pose of a target in high precision for Tele-LightSaber game.The PnP algorithm is used to obtain a rough pose,which is taken as the initial value of the iteration algorithm.The iteration algorithm utilizes the unit quaternions to represent the rotations.Then the result is optimized with Kalman filter.Considering the real-time and accuracy of the pose measurement,a fast feature extraction algorithm including object location,edge detection and corner detection is adopted to get the corners in high precision.The experiments and results verify the effectiveness of the proposed method.

Autonomous map query:robust visual localization in urban environments using Multilayer Feature Graph

When a vehicle travels in urban areas, onboard global positioning system （GPS） signals may be obstructed by high-rise buildings and thereby cannot provide accurate positions. It is proposed to perform localization by registering ground images to a 2D building boundary map which is generated from aerial images. Multilayer feature graphs （MFG） is employed to model building facades from the ground images. MFG was reported in the previous work to facilitate the robot scene understand- ing in urhan areas. By constructing MFG, the 2D/3D positions of features can be obtained, inclu- cling line segments, ideal lines, and all primary vertical planes. Finally, a voting-based feature weighted localization method is developed based on MFGs and the 2D building boundary map. The proposed method has been implemented and validated in physical experiments. In the proposed ex- periments, the algorithm has achieved an overall localization accuracy of 2.2m, which is better than commercial GPS working in open environments.

Uncalibrated visual servoing design for competitive networked robots

In this paper,a method with an eye-in-hand configuration is developed to hit targets during visual tracking for the TLS(Tele-Light Saber) game.It is not necessary to calibrate camera parameters and predict the trajectory of the moving object.Firstly,the expression of the image Jacobian matrix for the eye-in-hand configuration is proposed,and then an update law is designed to estimate the image Jacobian online.Furthermore,a control scheme is presented and the Lyapunov method is employed to prove asymptotic convergence of image errors.No assumption for the moving objects is needed.Finally,both simulation and experimental results are shown to support the approach in this paper.

Visual Localization in Urban Area Using Orthogonal Building Boundaries and a GIS Database

A framework is presented for robustly estimating the location of a mobile robot in urban areas based on images extracted from a monocular onboard camera, given a 2D map with building outlines with neither 3D geometric information nor appearance data. The proposed method firstly reconstructs a set of vertical planes by sampling and clustering vertical lines from the image with random sample consensus (RANSAC), using the derived 1D homographies to inform the planar model. Then, an optimal autonomous localization algorithm based on the 2D building boundary map is proposed. The physical experiments are carried out to validate the robustness and accuracy of our localization approach.

Enhanced Geometric Map:a 2D&3D Hybrid City Model of Large Scale Urban Environment for Robot Navigation

To facilitate scene understanding and robot navigation in large scale urban environment, a two-layer enhanced geometric map(EGMap) is designed using videos from a monocular onboard camera. The 2D layer of EGMap consists of a 2D building boundary map from top-down view and a 2D road map, which can support localization and advanced map-matching when compared with standard polyline-based maps. The 3D layer includes features such as 3D road model,and building facades with coplanar 3D vertical and horizontal line segments, which can provide the 3D metric features to localize the vehicles and flying-robots in 3D space. Starting from the 2D building boundary and road map, EGMap is initially constructed using feature fusion with geometric constraints under a line feature-based simultaneous localization and mapping(SLAM) framework iteratively and progressively. Then, a local bundle adjustment algorithm is proposed to jointly refine the camera localizations and EGMap features. Furthermore, the issues of uncertainty, memory use, time efficiency and obstacle effect in EGMap construction are discussed and analyzed. Physical experiments show that EGMap can be successfully constructed in large scale urban environment and the construction method is demonstrated to be very accurate and robust.