Temperature sensor based on the Er green upconverted emission in a fluorotellurite glass

The temperature dependence of the green upconverted emission from the two thermally coupled ²H_11/2 and ⁴S_3/2 levels of the Er³⁺ ion in a fluorotellurite glass has been analyzed as a function of the optically active ion concentration in order to check its availability as a temperature sensor. The infrared-to-green upconverted emission have been observed by the naked eyes after a cw laser diode excitation at 800 nm. The fluorescence intensity ratio between the thermally coupled emitting levels as well as the temperature sensitivity has been experimentally obtained up to 540 K. A better behaviour as a temperature sensor has been obtained for the less Er³⁺ concentrated glass with a maximum sensitivity of 54 × 10⁻⁴ K⁻¹ at 540 K, one of the highest found in rare-earth doped transparent materials.     

轮胎圆度检测控制系统设计

该文介绍了一种轮胎外形轮廓检测系统的检测原理、系统组成及控制系统设计。采用两级计算机控制系统,上位机完成数据的采集、处理、显示以及计算结果和检测参数的管理,下位机由三菱Q系列PLC的高性能CPUQ02H、运动控制器172H和J3系列伺服控制系统组成,驱动三支激光传感器运动,完成精确定位并通过它们来宾现对轮胎外形轮廓的精确测量。上、下位机之间采用以太网通信,更换规格时上位机自动下传传感器位置参数到PLC。该系统通过长时间在青岛高校软控股份有限公司生产的动平衡及不圆度试验机上的应用,表明其运行稳定,测试效率高。     

Effects of different sensors, flying altitudes, and pulse repetition frequencies on forest canopy metrics and biophysical stand properties derived from small-footprint airborne laser data

Canopy height distributions were created from small-footprint airborne laser scanner (ALS) data collected over 40 field sample plots with size 1000 m² located in mature conifer forest. ALS data were collected with two different instruments, i.e., the ALTM 1233 and ALTM 3100 laser scanners (Optech Inc.). The ALTM 1233 data were acquired at a flying altitude of 1200 m and a pulse repetition frequency (PRF) of 33 kHz. Three different acquisitions were carried out with ALTM 3100, i.e., (1) a flying altitude of 1100 m and a PRF of 50 kHz, (2) a flying altitude of 1100 m and a PRF of 100 kHz, and (3) a flying altitude of 2000 m and a PRF of 50 kHz. Height percentiles, mean and maximum height values, coefficients of variation of the heights, and canopy density at different height intervals above the ground were derived from the four different ALS datasets and for single + first and last echoes of the ALS data separately. The ALS-derived height- and density variables were assessed in pair-wise comparisons to evaluate the effects of (a) instrument, (b) flying altitude, and (c) PRF. A systematic shift in height values of up to 0.3 m between sensors when the first echoes were compared was demonstrated. Also the density-related variables differed significantly between the two instruments. Comparisons of flying altitudes and PRFs revealed upwards shifted canopy height distributions for the highest flying altitude (2000 m) and the lowest PRF (50 kHz). The distribution of echoes on different echo categories, i.e., single and multiple (first and last) echoes, differed significantly between acquisitions. The proportion of multiple echoes decreased with increasing flying altitude and PRF. Different echo categories have different properties since it is likely that single echoes tend to occur in the densest parts of the tree crowns, i.e., near the apex where the concentration of biological matter is highest and distance to the ground is largest. To assess the influence of instrument, flying altitude, and PRF on biophysical properties derived from ALS data, regression analysis was carried out to relate ALS-derived metrics to mean tree height (h_L) and timber volume (V). Cross validation revealed only minor differences in precision for the different ALS acquisitions, but systematic differences between acquisitions of up to 2.5% for h_L and 10.7% for V were found when comparing data from different acquisitions.     

Self-localization and obstacle avoidance for a mobile robot

This article presents a fast self-localization method based on ZigBee wireless sensor network and laser sensor, an obstacle avoidance algorithm based on ultrasonic sensors for a mobile robot. The positioning system and positioning theory of ZigBee which can obtain a rough global localization of the mobile robot are introduced. To realize accurate local positioning, a laser sensor is used to extract the features from environment, then the environmental features and global reference map can be matched. From the matched environmental features, the position and orientation of the mobile robot can be obtained. To enable the mobile robot to avoid obstacle in real-time, a heuristic fuzzy neural network is developed by using heuristic fuzzy rules and the Kohonen clustering network. The experiment results show the effectiveness of the proposed method.     

TMS320C6713B在船用捷联惯导系统中的应用

为了满足船用激光陀螺惯导系统的应用需要,设计基于DSP芯片TMS320C6713B和FPGA的导航计算机系统,FPGA实现对激光陀螺和加速度计输出信号的计数,完成DSP与外部的通信。该系统具有以TMS320C6713B为核心的单CPU结构,可以进行64位精度运算且运算速度快,能满足实时性要求。     

基于DSP的壁纸印刷花纹涂层厚度在线检测

在壁纸生产过程中,尤其是在花纹印刷过程中,有效地在线测量花纹涂层厚度,对于减少壁纸生产的次品率和提高生产效率至关重要。本课题针对壁纸印刷花纹涂层厚度在线检测问题进行了研究,利用激光传感器测厚原理,基于TI公司生产的TMS320F2812DSP芯片为硬件核心处理器,完成了花纹涂层厚度的非接触在线测量。     

基于激光雷达距离图像的道路边缘检测与跟踪

论述了将激光雷达的距离图像信息用于道路检测和跟踪。首先将扫描点进行聚类分析对道路边缘进行检测和对所检测的边缘进行最小二乘直线拟合,在成功检测道路边缘后,利用Kalman滤波对道路边缘进行跟踪。实验证明该算法具有检测准确且鲁棒性好的特点。     

Contribution of laser microdissection-based technology to proteomic analysis in hepatocellular carcinoma developing on cirrhosis

Hepatocellular carcinoma (HCC) is a major cause of cancer worldwide. Proteomic studies provide opportunities to uncover targets for the diagnosis and treatment of this disease. However, in HCC developing in a setting of cirrhosis, the detection of proteome alterations may be hampered by the increased cellular heterogeneity of tissue when analysing global liver homogenates. The aim of this study was to evaluate whether the identification of proteome alterations in these HCC cases was improved when the differential protein profile between tumour and non-tumour areas of liver was determined using hepatocytes isolated by laser microdissection (LM). Differential profiles established with LM-hepatocytes and liver section homogenates using 2-DE and MS exhibited noticeable differences: 30% of the protein spots with deregulated expression in tumorous LM-samples did not display any modification in homogenates; conversely 15% of proteins altered in tumorous homogenates were not impaired in LM-hepatocytes. These alterations resulted from the presence in cirrhotic liver of fibrotic stroma which displayed a protein pattern different from that determined in LM-hepatocytes. In conclusion, our data demonstrate the interest of LM in distinguishing between fibrotic and hepatocyte proteome alterations and thus the benefit of LM to proteome studies of HCC developing in a context of cirrhosis.     

Parameterization for reconstruction of 3D freeform objects from laser-scanned data based on a PDE method

Published online: 19 July 2001     

PVC异型材原料粒径分布测试方法的评价

本文介绍了三种PVC异型材原料粒径分布的测试方法:沉降法(检测时间长,重现性差)、筛分法(操作复杂)、激光法(准确方便)。