Intrinsic UV reflection and fluorescence studies for water sorption in polycarbonate, polyurethane and poly(ethylene terephthalate) films

Intrinsic UV reflection and fluorescence behaviors of polycarbonate, polyurethane and poly(ethylene terephthalate) films were investigated in order to characterize the interaction of water in these films. During water sorption process, UV reflection spectra of polycarbonate and polyurethane films showed little peak position changes. Fluorescence emission spectra of polycarbonate films showed red spectral shifts from 332 nm with water immersion time. This red-shifted peak could be due to phenyl-2-phenoxybenzoate, which is one of the major thermal degradation products in polycarbonate. Fluorescence peaks of polyurethane films appeared at two different positions and the ratio of these peak intensities increased with increasing immersion time. In the case of PET films, the UV reflection spectrum showed the peak intensity around 340 nm to change in response to water sorption. The fluorescence near 388 nm probably due to ground state dimer exhibited sensitivity with water sorption, when excited at 340 nm.     

关于慈利县中德财政合作造林项目建设的思考

阐述了中德财政合作造林项目在慈利县林业建设所取得的成效,指出了项目建设过程中存在的问题,并相应提出了解决问题的建议.     

Illumination invariant segmentation of vegetation for time series wheat images based on decision tree model

Effective and efficient segmentation of vegetation from digital plant images is an actively studied topic in crop phenotyping. Many of the formerly proposed methods showed good performance in the extraction under controlled light conditions but it is still hard to properly extract only vegetation from RGB images taken under natural light condition where the images can contain shadowed and lighted parts with specularly reflected parts of plants. In this paper, we propose a robust method to extract vegetation from the plant images taken under natural light conditions using wheat images. The method is based on a machine learning process, decision tree and image noise reduction filters. We adopted the CART algorithm to create a decision tree in the training process and examined its performance using test images, comparing it with the performances of other methods such as ExG, ExG-ExR and Modified ExG which are widely used recently. The results showed that the accuracy of the vegetation extraction by the proposed method was significantly better than that of the other methods particularly for the images which include strongly shadowed and specularly reflected parts. The proposed method also has an advantage that the same model can be applied to different images without requiring a threshold adjustment for each image.     

红外反射式播种机电子监测装置的设计

针对目前播种机电子监测装置普遍存在的安装不便、布线复杂、维护困难和实用性差等问题,设计开发了红外反射式播种机电子监测装置,较好地克服了上述缺点。该装置的探头采用了红外反射式的检测原理,以高速单片机为核心,能实现软件抗干扰及计数精度补偿,体积小巧,可单侧安装,适用于各种排种管。同时,采用无线数据传输方式及无极性二总线布线方式,极大地简化了布线工作,尤其适用于大型宽幅播种机的作业需求。该装置与2BJQ-9气吸式精密播种机配套的田间试验结果表明:故障检知准确率为100%,落种计数检测精度>93%,具备声光告警功能,人机界面友好,操作方便,为播种机电子监测装置的广泛应用提供了新思路。     

利用漫反射光测量滑动链板的塌角

利用光学测量滑动链板塌角的方法，即通过测量滑动链板表面漫反射光的强度分布，获得链板塌角的信息。本装置用６３２８埃的Ｈｅ－Ｎｅ激光器和ＣＣＤ（电荷藕合摄像器件）作为光的发射接收系统来提取信号。从理论上推导出了它的漫反射光的强度分布，并对漫反射光的亮度、最大偏移作了详细的计算和讨论，并讨论了ＣＣＤ的位置约束关系，从而提出利用漫反射光束来测量链板塌角的变化规律。     

基于SIRI和CNN的苹果隐性损伤检测方法

苹果从采摘到销售过程中易发生机械损伤,需要及时剔除以避免腐烂变质。然而机械损伤早期苹果外观颜色变化不明显,通常表现为隐性损伤,检测比较困难。提出了一种基于结构光反射成像(SIRI)和卷积神经网络(CNN)的苹果隐性损伤检测方法。通过搭建SIRI系统,采集待测苹果调制的结构光图像,再利用三相位解调法提取交流分量,增强苹果隐性损伤对比度;然后利用交流分量图像制作苹果隐性损伤数据集,并使用基于CNN的语义分割网络FCN、UNet、HRNet、PSPNet、DeepLabv3+、LRASPP和SegNet训练损伤检测模型,多组试验结果表明上述模型均能有效地检测出不同情况下的苹果隐性损伤。其中HRNet模型精确率、召回率、F1值和平均交并比较高,分别为97.96%、97.52%、97.74%和97.58%,但检测速度仅为60 f/s; PSPNet模型检测速度较快,可达到217 f/s,但其检测精度略低,精确率、召回率、F1值和平均交并比分别为97.10%、94.57%、95.82%和95.90%。     

Design development of porous collar barrier for offshore floating fish cage against wave action,debris and predators

This paper presents a design concept of a porous collar barrier for a novel floating open-net fish cage that is integrated with a floating spar wind turbine (referred to as COSPAR fish cage). The COSPAR fish cage has an octagonal shape with each side length of 30m. The collar barrier, having an array of rectangular cut-outs with round corners, is installed at the top portion of the cage to attenuate wave transmission inside the cage as well as to protect fish from external predators and debris. Single and double collar barrier designs corresponding to single net and double net cages are studied. The wave transmission, reflection and energy-loss coefficients of barriers are determined from numerical analysis based on the linear potential wave theory and the eigenfunction expansion method. Various underwater heights (2m ≤ h ≤ 8m) and porosity (0.25≤ ε ≤ 0.75) of the collar barriers are examined with the view to obtaining the barrier design for minimal transmission coefficient and energy-loss coefficient. Without a collar barrier, the single net and double net cage can only provide average wave transmission coefficients of 0.9 and 0.8, respectively. This study finds that the transmission coefficient could be reduced below 0.4 by having a single collar barrier with h = 4m and ε = 0.25. On the other hand, the transmission coefficient could be further reduced below 0.3 by a double collar barrier with the same h and ε. In addition, the double collar barrier gives lower energy-loss coefficient and better proofing against fish escape, biosecurity and predator intrusion than the single collar barrier. A double collar barrier design with porosity combination of ε₁ = 0.25, ε₂ = 0.5 is recommended for the COSPAR fish cage as it yields competitive wave scattering performances and saves collar material by 25 % when compared with the best performing porosity combination of ε₁ = ε₂ = 0.25.     

中国传统健身功法在西方传播的文化基础

随着中国各改革开放的不断深入,中国与西方的文化交流也逐渐进入一个崭新的阶段而从交流走向融合。中国传统健身功法在西方传播也受到这种文化交流趋势的影响,使得这种传播成为西方的一种文化现象,其原因在于中、西方文化具有先天的共通共融的元素,特别是西方宗教文化与当代文化反思为中国传统健身功法的传播提供了坚实的文化基础。     

植物生理学实验课程教学改革与探索

根据人才培养的需要,从制订教学大纲,优化整合实验内容,改革教学方法,完善考核方式等方面,探讨了植物生理实验课程教学改革。     

自然背景下基于反射模型的树叶彩色图像分割

为实现固碳释氧测量中叶片图像的高精度分割,提出一种基于反射模型的树叶彩色图像分割算法.首先,在RGB颜色空间中,针对光照对于叶片颜色不一致的影响,采用改进的白平衡方法进行滤波;其次,针对RGB颜色空间的非均匀性、色域窄、亮度分量混合的问题,将其变换到Lab颜色空间,去除亮度分量,消除光照对于叶片分割的影响;然后,依据Lab颜色空间的均匀性,定义颜色特征的欧氏距离为聚类准则;最后采用最小分类器进行聚类分割.实验结果的对比分析表明该方法是有效的.