联合Terra/Aqua MODIS多角度多光谱数据反演冬小麦叶面积指数

Terra与Aqua双星搭载的MODIS传感器可实现每日上下午分别对同一地点观测一次,并且由于卫星轨道漂移形成累积连续多天的多角度观测特点,加上多通道的光谱响应,极大地丰富了地表目标的观测信息,为LAI等地表参数的实时准确反演提供了可能。该文利用MODIS双星高质量的连续多天的多波段地表反射率数据,结合PROSAIL(PROSPECT+SAIL,properties spectra+scattering by arbitrarily inclined leaves)模型和查找表方法反演冬小麦LAI,并与MODIS LAI产品及野外采样点实测LAI对比,结果表明,联合双星高质量的多角度多波段数据能够较准确反演冬小麦LAI,其反演结果无论从空间分布还是时序变化特征来讲,较MODIS LAI产品更符合实际情况,也更接近地面实测值。该文的研究为充分利用MODIS数据的角度和光谱信息反演小麦等农作物的LAI提供了一定的借鉴。     

新课程背景下政治教师的教学反思

长期以来,政治课教学在一定程度上存在着失效和失信的问题,教学反思是政治教师成长中的重要条件,能够使政治教师成为教学中的自觉者、促进知识结构完善的学习者、促进教育观念更新的变革者。文章在分析新课程背景下政治教师教学反恩的必要性的基础上,探讨了教学反思的内容及策略。     

主/从机器人系统设计与双向伺服控制

建立了主／从异构式机器人力反馈遥操作控制系统。主操作系统采用2个2-DOF操作手,分别采用伺服阀控制液压马达获得2个解耦的旋转自由度。用力信息对伺服阀进行控制以驱动主操作手运动,解决主手操纵力不能直接驱动主操作手液压马达的问题。从机器人为4-DOF串联关节型四自由度机器人,采用比例方向阀控制。分别采用力反射伺服型和力对称型双向伺服控制策略,对主／从机器人系统进行遥操作力反馈双向伺服控制实验研究。验证了本设计的主操作手结构的合理性,力对称型双向伺服控制策略具有较好的控制性能。     

全反射X-射线荧光法分析茶叶中的矿质元素

用全反射X -射线荧光法 (TXRF)分析了江西婺绿和宁红茶的矿质元素含量。结果表明 ,所测茶叶中P、S、K、Ca的含量在 2 4 70～ 30 70 0 μg/g ;Mn、Fe在 2 0 6～ 10 70 μg/g ;Ti、Ni、Cu、Zn、Rb、Sr、Ba在 5 5～ 12 2 μg/g ;Pb含量均小于 4 0 μg/g (干基 )。宁红还表现出 ,品质越好 ,P、Ni、Zn含量越高 ,而K、Ca、Mn、Sr、Ba含量则相反。茶汤中K、Rb、Ni的浸出率为 30 5%～ 86 4% ;P、S、Mn、Cu、Zn、Sr为 11 6 %～ 4 2 4% ;Ca为 7 2 %～ 12 6 % ;Fe为 1 1% -2 6 %。茶汤中Ti、Ba、Pb的含量均低于TXRF法的检测限。宁红茶汤还表现出 ,品质越好 ,K、Ca、Mn、Zn、Rb、Sr的浸出率越高。但红茶汤中的K、Zn、Rb、Ni浸出率明显低于绿茶     

西部新院校图书馆在本科教学评估中的经验与反思

2000年以来升格的本科新院校先后迎来教育部"本科教学工作水平评估".西部新院校图书馆要确保达到"管理手段先进、图书馆使用效果好"和"生均藏书量100册、生均年进书量4册"的标准,时间紧,任务重,压力大.除争取学院加大投入外,必须准确理解、分解评估指标.硬件从实,软件从严.从实盘底,及时调整.艰苦奋斗,突出特点.避免突击采购,又好又快地建设数字化图书馆.     

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.     

“结构家庭疗法”介入青少年个案社会工作探析

基于结构家庭理论视角,运用青少年社会工作专业方法和技巧,从案主的家庭出发,为案主提供一些必要的服务,帮助案主改善与父亲的关系,解决学习障碍,改善偏差行为等。本案虽未达到预期的效果,但通过此案例反思结构家庭疗法对青少年社会工作实践的意义可以推动青少年社会工作的发展。     

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.     

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.     

提高人才培养质量的思考——以苏州农业职业技术学院为例

我国高等职业教育在经历了多年的发展后,取得了突破性的进展,但如何更好地提高人才培养的质量,仍然在不断探索。高职人才培养目标是真正体现以市场为导向,本着以人为本的理念,培养出高素质的技能型人才。提出了提高人才培养质量的措施是明确培养目标,加强专业建设;加大课改力度,做实课程建设;加强团队建设,提高双师素质;加大教学投入,不断改善基础实施;推进教育创新,深化教学改革。