基于激光诱导荧光高光谱技术无损检测脐橙表面敌敌畏残留

常规化学方法检测农药残留不仅对样品具有破坏性,而且费时费力。本文以激光诱导荧光结合高光谱图像技术为手段,对脐橙表面的敌敌畏农药残留进行光谱无损检测;实验方法是在脐橙表面,喷施用自来水配制的不同浓度的敌敌畏农药溶液,在实验室条件下风干后,采集激光诱导荧光高光谱图像,再用气相色谱法检测脐橙表面的农药残留量,应用偏最小二乘(Partial least squares,PLS)方法建立农药残留的预测模型,并找出最佳光谱区间,然后应用支持向量机(Support vectormachine,SVM)方法在最佳光谱区间的基础上建立农药残留的预测模型;所建模型结果其预测集样品的农药残留量实测值(0.4862~10.3791mg/kg)和预测值之间的相关系数为0.8101;实验结果说明,以激光诱导荧光结合高光谱技术为手段的无损检测技术,在检测脐橙农药残留方面是有可行性的。     

果园智能化作业装备自主导航技术研究进展

果园生产管理主要包括喷药、施肥、割草、修剪、授粉、疏花和采收分级等作业环节,需要大量的人力投入,随着我国人口老龄化程度加剧,亟需果园生产管理由机械化向智能化转型升级。自主导航技术是果园机械化装备实现智能化的关键技术。本文围绕果园智能化作业装备导航控制需求,结合国内外研究现状,分别阐述了包含导航定位信息和障碍物信息的果园作业场景感知技术,导航地图构建、导航路径提取和路径规划技术,行走底盘运动学模型构建、运动控制技术,多机协同控制、远程交互控制技术等。随着智慧农业发展,智慧果园已成为果园未来发展方向,果园智能化作业装备是智慧果园建设必不可少的关键环节,在此基础上,归纳了我国果园智能化作业装备自主导航技术发展面临的问题为：环境感知能力不足、路径提取不稳定、局部路径规划不灵活、导航系统环境适应性欠缺、多机协同和远程控制不成熟等,提出了多传感器融合的环境感知与路径提取、完整路径规划、强通用性果园导航、大型果园多作业环节的多机协同与远程操作等未来发展方向。     

机载激光雷达和地基激光雷达林业应用现状

激光雷达技术可以直接获取地物的三维信息,在森林参数反演方面具有独特优势。近年来,机载激光雷达与地基激光雷达在林业上的应用取得很大进展,在森林调查中应用广泛。文中介绍了机载激光雷达与地基激光雷达在森林参数提取中的应用,并分析了两者的优缺点;概述了2种数据结合在森林参数反演中的应用,并对应用前景进行了展望。     

粉纹夜蛾培养细胞对家蚕微孢子虫的吞噬及与孢壁蛋白的关系

解明家蚕微孢子虫(Nosema bombycis,Nb)入侵宿主细胞的相关因素,有助于深入研究Nb对家蚕的侵染机制。利用激光共聚焦显微镜观察Nb孢子接种粉纹夜蛾(Trichoplusiani,Tn)培养细胞48h后孢子的分布状态和培养细胞的生长情况,并对接种Nb孢子后的Tn培养细胞培养物总蛋白进行SDS-PAGE分析,证实经0.2mol/LKOH预处理的Nb孢子可以被Tn培养细胞所吞噬。对Nb孢子孢壁蛋白的SDS-PAGE分析显示,Nb孢子经KOH预处理后,大小为80kD和12kD的孢壁蛋白带缺失或明显减弱,30kD的孢壁蛋白带丰度降低。推测KOH预处理使Nb孢子部分孢壁蛋白被分解(部分或完全)或使蛋白结构发生变化,由此影响了Nb孢子与Tn培养细胞的相互作用关系,有利于Tn培养细胞对Nb孢子的吞噬。     

Application of epifluorescence light microscopy (EFLM) to study the microstructure of wheat dough: a comparison with confocal scanning laser microscopy (CSLM) technique

To study dough microstructure, epifluorescence light microscopy (EFLM) combined with digital image processing software was used, which enabled an improved image quality. A comparison was made between EFLM and confocal scanning laser microscopy (CSLM) methods. Both techniques were satisfactorily able to demonstrate changes in the dough microstructure upon different stages of z-blade mixing. Dough mixed for a shorter time (under-mixed) showed a heterogeneous structure with coarse protein domains and clusters of starch due to local segregation or de-mixing effect. Increasing mixing time (optimal mixing) led to development of interconnected gluten network covering starch granules throughout the dough, representing optimal development. Over-mixing led to formation of a homogeneous dough microstructure in which the gluten phase showed a fine distribution throughout the dough. Using a double staining method in the preparation of samples for both microscopic techniques it was possible to observe gluten network structures together with starch granules. Moreover, special features of image processing software described in this study enabled us to improve EFLM images and to obtain comparable images with CSLM. This could favour a low cost and a convenient microscopic observation of biomaterials.     

Carbon Dioxide Laser Keratectomy as a Treatment Option for Equine Corneal Stromal Abscessation: A Comparison to Lamellar Keratectomy and Penetrating Keratoplasty

Carbon dioxide (CO₂) laser keratectomy was compared to lamellar keratectomy (LK) and penetrating keratoplasty (PK) as a potential treatment option for equine corneal stromal abscessation. The medical records of 35 client owned horses undergoing surgical management of stromal abscessation were reviewed. Among those 17 underwent LK, 3 PK and 15 CO₂ laser keratectomy. Healing of the stromal abscess was achieved in all treated eyes. Those horses undergoing CO₂ laser keratectomy demonstrated few complications, and the time to healing and cosmetic outcome was comparable to those horses undergoing LK and PK.     

Effects of auxiliary data source and inventory unit size on the efficiency of sample-based coarse woody debris inventory

The efficiency of a sample-based inventory can be greatly improved if lower cost information on the study area is utilized. It has been observed that the use of airborne laser scanning (ALS) data in the design phase may improve the efficiency of dead wood (coarse woody debris, CWD) volume inventory notably, i.e. a smaller standard error of the mean is observed with the same inventory costs. In the present case, several auxiliary data sources were employed in the design phase by using ‘probability proportional to size’ sampling to select the sample units to be inventoried in the field. It was observed that a combination of ALS data with either aerial photographs or stand-register data can improve the sampling efficiency even more than the use of ALS as a single data source. Since these additional data sources are often gathered for the inventory of living trees, their use does not incur extra expenses for CWD assessment. Thus, the use of these data separately or together with ALS data can greatly improve the cost-efficiency of a CWD volume inventory. It was also observed that the size of the sample units has a slight effect on the sampling efficiency. Even though the improvement in the sampling efficiency was usually greater with larger sample unit sizes, the CWD volume inventory was most efficient with moderate grid cell sizes.     

Ca对AZ31镁合金CO2激光焊接接头组织和性能的影响

采用添加填充材料的CO2激光焊接工艺对AZ31镁合金薄板进行焊接,研究了不同Ca含量对焊缝金属的显微组织和力学性能的影响.结果表明：当激光功率为1 500 W,焊接速度为3 m/min时, AZ31镁合金CO2激光焊接的焊缝金属中添加一定量的σCa＜0.19%元素,可以得到成分相对较均匀、组织细小的焊缝.当填充带材为AZC04(焊缝中σCa=0.19%)时,焊缝区晶粒相对细小,析出相细小弥散,此时焊接接头的力学性能最优,焊接效率基本可达到100%.     

数字近景摄影测量辅助三维激光扫描用于森林固定样地测树原理探讨

近景摄影测量和近年来发展起来的三维激光扫描技术已广泛用于树木三维数据的获取,通过近景摄影测量技术和三维激光扫描方法获得的数据各有优缺点,但它们优势互补构成获取立木数据强大的工具。三维激光扫描有快速获取数据的优点,缺点是容易留下没扫描的空白区域（扫描漏洞）;摄影测量能根据人们的主观愿望布置测量控制网,很灵活地采集数据点,能够补充扫描漏洞没有数据点的缺陷,缺点是因布置测量控制网,要增加劳动强度,再者在影象上灰度变化不明显的部位无法获得同名像点,在一定程度上制约着三维建模的精度。试图探讨利用近景摄影测量辅助三维激光扫描的数据采集技术来恢复单木空间实体,计算胸径、任一处的直径、树高、树冠体积等测树指标,最后得出材积方程,服务于森林资源的精准监测。     

两种布鲁氏菌弱毒株侵染小鼠巨噬细胞过程的荧光表征及分析

通过对绿色荧光蛋白（GFP）布鲁氏菌弱菌株M5（GFP-M5）和S19（GFP-S19）侵染小鼠巨噬细胞（RAW264.7）及对其与胞内溶酶体、内质网、高尔基体初次结合所用时间进行测定,探讨分析两种布鲁氏菌弱毒株侵染小鼠巨噬细胞过程的荧光表征。将GFP-M5和GFP-S19分不同时间段分别侵染RAW264.7,利用激光共聚焦和流式细胞仪观察和检测。结果显示,GFP-M5和GFP-S19均构建成功。布鲁氏菌M5和S19及GFP-M5和GFP-S19侵染RAW264.7后胞内生存能力无明显差异。GFP-M5和GFP-S19侵染30 min后均已进入小鼠巨噬细胞,2 h分别到达溶酶体、内质网和高尔基体。而两种弱毒株在1、2、3、4 h与各细胞器结合率相近。流式细胞仪检测结果显示,GFP-M5和GFP-S19侵染RAW264.7的GFP⁺细胞含量无显著差异（P>0.05）。结果提示,两种弱毒株在侵染进入宿主细胞的初期及侵袭能力并没有明显差异。