Measuring the height at the withers of ponies at a competition and at home using a laser device

Measuring the height of ponies at the withers is currently a prerequisite at Fédération Equestre Internationale (FEI) competitions. A pony measured at a competition site must not measure more than 151 cm with, or 150 cm without horse shoes. When a pony exceeds the regulated height, it is excluded from participation in the competition. Moreover, the sale value of a pony can decrease dramatically if by height measurement it is designated as a ‘horse’. The aim of this study was firstly to determine whether measuring ponies at the withers with a laser device is repeatable; secondly, to evaluate whether laser measurements are more accurate than use of a conventional measuring stick, and, thirdly, to evaluate the difference in height at the withers between ponies at home and the height of the same ponies at a competition.Fifteen clinically healthy horses and 38 healthy ponies were used in the study. A statistical evaluation was performed to determine whether there was a correlation or a significant difference between measurements (P < 0.01). The repeatability of the laser measurements, the comparison of the use of the laser versus the measuring stick, and of the measurements done at home compared to the competition site were all very high (0.999, 0.0997 and 0.992, respectively; P < 0.01). The mean height measured at a competition was 141.9 ± 9.0 cm and of the same ponies at home was 142.4 ± 9.1 cm. This difference was not significantly different, although there was a tendency for ponies measured at home to have a higher height at the withers compared to the same ponies at a competition.     

梨自花及异花授粉对其花柱自发荧光的影响

 利用激光共聚焦显微技术研究了砂梨(Pyrus serotina Rehd．)品种‘丰水’ 自花授粉和异花(‘二十世纪’)授粉16 h后花柱自发荧光的分布规律。发现未授粉花柱整体的自发荧光比较弱。但从柱头端向子房端花柱自发荧光呈上升趋势;异花授粉和自花授粉后花柱整体的自发荧光都有所增加;授粉后自发荧光变化最大的部位在柱头区域; 自花授粉后,在柱头及距柱头0～400an范围内荧光值较高,其他区域的荧光值相近;而异花授粉后在花柱的中部(距柱头1500～2050an范围内)荧光值最低; 自花授粉后自发荧光除柱头以外主要分布在花柱的边缘区域;异花授粉后自发荧光在花柱上半部的分布情况与自花授粉类似,下半部分布相对均匀。关键词：中图分类号： 文     

Impacts of connexin 43 degradation on conduction velocity during acute myocardial ischemia

AIM:To study the impacts of the myocardial connexin 43 degradation on conduction velocity during acute myocardial ischemia.METHODS: Studies were carried out in 16 dogs which were randomly divided into control group(n=4) and ischemia group(n=12). The acute myocardial ischemia was induced by ligation of the left anterior descending coronary artery. The conduction velocity of ischemic myocardium was determined. The content of Cx43 of the ischemic myocardium was examined by laser confocal microscopy with a double-label immunohistochemistry technique. RESULTS:(1)The Cx43 degraded rapidly during acute myocardial ischemia, and the conduction velocity of ischemic myocardium declined greatly; (2)The conduction velocity correlated positively with the Cx43 pixel density in each small region of ischemic myocardium; (3) The Cx43 pixel density decreased over 50% in the region which occuring permanent conduction block.CONCLUSION: These data suggest the degradation of Cx43 decreases the conduction velocity greatly during acute short time myocardial ischemia, and severe degradation of Cx43 would lead to permanent conduction block.     

激光熔覆Ni基合金/碳化物涂层组织及冲刷腐蚀磨损性能

在2Cr13马氏体不锈钢基材上激光多道搭接熔覆Ni—Cr3C2和Ni—WC复合涂层,考察两种激光熔覆层的微观组织、显微硬度对冲刷腐蚀磨损性能的影响,并与不锈钢基材对比。试验结果表明,两种涂层具有不同的凝固组织特征。含有未完全溶解WC硬质相的Ni—WC涂层比Cr3C2硬质相完全溶解的Ni—Cr3C2双相涂层的显微硬度高出约300HV,两种激光涂层的冲刷腐蚀磨损速率分别比不锈钢基材降低30％和60％。冲刷腐蚀磨损抗力的提高与熔覆层的组织状态、碳化物种类和数量以及涂层的韧化性能等因素密切相关。     

激光微造型凸轮副的摩擦磨损

采用UMT-2多功能摩擦磨损实验机,模拟内燃机凸轮/滚轮工况条件,考察了多种激光微造型形貌试样表面的摩擦磨损特性.实验结果发现,与未处理光滑表面相比,激光微造型试样表面的耐磨、抗擦伤性显著提高,其中,凹坑造型表面的摩擦因数显著下降,而凹槽表面的摩擦因数相对较大.这说明凹槽形貌会增大表面摩擦,而凹坑形貌具有一定的减摩效果.合理选择凹坑的深度及其面积占有率,并进行微形貌几何参数的优化组合,可达到最佳减摩效果.     

计算机控制激光扫描识别木段横断面图形的研究

针对原木在确定最佳旋切回转中心时,需要识别原木横断面外形几何尺寸而研究、设计了采用计算机控制的激光扫描检测系统,对原木进行动态测试、数据转换及图形显示。其方法是沿木段长度方向均匀设置５～７个激光传感器,当木段旋转时,起动激光传感器进行数据采集,每隔１５°扫描一个点,在各横断面圆周上共采集２４个点的数据,由计算机计算出每个角度上原木表面到中心轴的距离,并对这些数据通过坐标变换,在计算机上绘制出原木横断面几何图型。测试结果表明,该系统的综合测量精度达到±１ｍｍ。     

Thermal constants of wood during the heating process measured with the laser flash method

The thermal diffusivity, specific heat, and thermal conductivity of 13 species of wood were measured by means of the laser flash method to investigate the thermal properties of wood during the heating process. The temperature ranged from room temperature to 270°C in air or under vacuum. The thermal diffusivity varied little during the heating process up to 240°C. The values in air were larger than those under vacuum. There was a linear relation between the specific heat and the ambient temperature, and the specific heat under vacuum was larger than that in air at high temperature. The thermal conductivity increased with density and the ambient temperature. To discuss the effects of the atmospheric conditions on the thermal constants of wood, a theoretical model of thermal conductivity was proposed and its validity examined, where the wood was assumed to be a uniformly distributed material composed of cell walls and air.Part of this paper was presented at the 47th annual meeting of Japan Wood Research Society at Kochi, April 1997     

基于激光扫描点云数据的植物叶片三维可视化

利用三维激光扫描系统得到单个黄瓜叶片的点云数据,借助imageware软件对点云数据进行缩减和坐标转换处理,并在OpenGL中通过三角网格化处理得到能反映叶片真实几何形态的三维模型,同时运用着色技术实现了单个叶片的三维可视化,达到了较逼真的可视化效果,为建立黄瓜植株三维模型的可视化提供了基础。     

激光衍射法测定中国典型土壤颗粒分布的模型建立与验证

【目的】探讨快速测定中国典型土壤粒径分布的方法,提高土壤颗粒粒径分布测定的准确性。【方法】采用激光衍射法和传统吸管法（简称吸管法）对比研究中国15个省20种不同类型土壤的颗粒分布。【结果】激光法和吸管法测定的砂粒、粉粒和黏粒含量均呈显著的线性正相关。其中,激光法测定的黏粒和砂粒含量比吸管法测定的值平均低73.4 g•kg-1和59.6 g•kg-1,而粉粒含量平均较吸管法高131.2 g•kg-1。通过建立土壤粒径的累积分布曲线函数,建立了两种方法测定结果的转换模型。激光法测出的土壤颗粒粒径累积分布曲线函数为：y=1 000x/（b+x）（x代表粒径大小,y代表小于该粒径的颗粒所占的质量）。吸管法测得的相应粒径累积曲线函数为y=1 000x/（1.32b-1.01+x）。根据该函数得到的土壤颗粒粒径质量百分含量查质地分类三角图,即可判断土壤的质地类型。【结论】激光粒度仪检测结果通过转换模型修正,可以较好地反映土壤机械组成及土壤质地情况,可以快速准确地用于土壤颗粒组成的测定。