直角坐标红花采摘机器人的设计与试验

针对红花采摘仍以人工采摘为主、采摘效率低下、费时费力等问题,结合红花物理生长特性及红花种植模式设计了一种直角坐标红花采摘机器人.对直角坐标采摘系统进行参数计算,确定直角坐标采摘系统X轴总长为900 mm,Y轴总长为700 mm,Z轴的行程范围为698 mm.由静力学仿真试验可知:在采摘过程中应用普通碳钢应变最小为6.5...     

铜离子对转基因和非转基因红鲤行为的影响

在构建转基因红鲤的基础上,采用生物预警系统比较和分析了非转基因和转基因红鲤(Cyprinus carpio)在不同铜离子浓度条件下的游速和活动范围的变化。转基因红鲤和非转基因红鲤孵育自同一批受精卵,转基因红鲤体长(5.31±0.64)cm、体重(3.40±0.55)g,非转基因红鲤体长(4.58±0.59)cm、体重(2.40±0.58)g。CuSO4的浓度设置0(对照)、5、15、25、35和45μg/L共6组。生物预警系统包括储水池、数字摄像仪和数据运算处理器,可以记录鱼的二维移动轨迹,并计算出鱼的平均游速。试验结果表明,非转基因和转基因红鲤的平均游速分别为:对照组1、1.57 BL/s,5μg/L组1.24、1.07 BL/s,15μg/L组1.61、1.03 BL/s,25μg/L组1.50、1.59 BL/s,35μg/L组1.62、1.61 BL/s,45μg/L组1.25、1.97BL/s。非转基因和转基因红鲤的活动范围:除35μg/L组外,其他组的坐标X值非转基因与转基因红鲤间差异都极显著(P<0.01);对照组、5和25μg/L浓度组,转基因红鲤坐标X值极显著高于非转基因红鲤;15和45μg/L浓度组,非转基因红鲤坐标X值极显著高于转基因红鲤。低于45μg/L时,铜离子没有对转基因和非转基因红鲤产生明显的毒性;在45μg/L浓度组,转基因红鲤对铜离子不敏感,而非转基因红鲤较敏感。     

东北黑土有机无机复合体组成

在系统研究了东北黑土耕层有机无机复合体组成的基础上,深入研究了各组复合体含量随纬度的变化规律,并用三角坐标法研究了不同类型土壤及同一类型不同肥力土壤有机无机复合体分布特征。结果表明:东北黑土有机无机复合体组成中,G1组复合体是主要部分,平均为55.01%,其次为G0组复合体,平均为33.68%,G2组含量最低,平均为11.31%。G1组、G2组复合体含量自北向南有渐减趋势,与纬度分别呈显著正相关;G1+G2和G0+G1+G2自北向南也呈渐减趋势,与纬度分别呈极显著正相关。三角坐标中不同类型土壤的分布区域,同一类型不同肥力土壤的分布区域是特征性的。     

一种适合线划图坐标系统转换的方法

对旧坐标系统下线划图的利用,关键在于对原有线划图的坐标系统进行转换,通常选用的转换方法是在平面上进行．基于平面的线划图转换方法易于实现,但也具有一些局限性．分析得出当前线划图坐标系统转换方法具有不同区域的长度变形使得尺度比参数无法统一、不便于地方独立坐标系下的线划图向国家坐标系进行转换这两方面的局限性,提出在椭球面上实...     

Herbivorous fishes and the potential of Caribbean marine reserves to preserve coral reef ecosystems

• 1. The development of macroalgae to the detriment of corals is now one of the major threats to coral reefs. Herbivorous fishes are partly responsible for algal regulation on coral reefs and their overexploitation favours the shift from scleractinian coral‐dominated systems towards macroalgae‐dominated systems.
• 2. Marine protected areas (MPAs) that have been established worldwide may benefit coral reefs through the maintenance of high densities of herbivorous fishes which regulate algal growth.
• 3. The paper assesses whether small MPAs in the Caribbean are able to enhance herbivorous fish stock and by controlling macroalgae help to maintain reef ecosystems. A visual census using band‐transects was undertaken around Guadeloupe island where marine reserves have been in place since 1979. The effects of MPAs on both benthic communities and herbivorous fishes are examined.
• 4. Inside MPAs, herbivorous fish biomass was almost twice as high as outside MPAs and macroalgal cover was significantly lower. Fish size class distributions revealed that large individuals occurred mainly inside MPAs and that few male individuals were found outside MPAs. Copyright © 2010 John Wiley & Sons, Ltd.

     

完整系统三阶Lagrange方程的一种推导与讨论

从牛顿运动方程出发,推导了完整系统关于广义加速度的Lagrange方程.讨论了该方程与传统分析力学中的Lagrange方程的相容性问题.结果显示,三阶Lagrange方程可以通过对Lagrange方程求一阶时间导数得到,表明它们是相容的.因此三阶Lagrange方程提供了一种不同于传统Lagrange方程方法的求解物体运动方程的途径.     

Variety specific responses of cauliflower varieties (Brassica oleracea var. botrytis) to different N application rates on yield,colour and ascorbic acid content at harvest

The influence of five nitrogen (N) application rates (60, 90, 120, 150 and 180?kg?N/ha) were evaluated using limestone ammonium nitrate on the curd fresh and dry mass, size, chromaticity coordinates, L*, a*, b* and ascorbic acid content in cauliflower varieties (Largardo, Eskimo and CF-744) during the 2015 and 2016 seasons. Commercial standard 120?kg?N/ha was included as a control. Variety ‘Largardo’ showed weak response to N application rates and can be regarded as the least sensitive variety for lower N use. Curd fresh and dry mass and size were not affected at lower N application rates of 60 and 90?kg/ha in ‘Largardo’ compared to the other two varieties. However, L*, b* colour value and ascorbic acid content was higher at lower N application rates <90?kg?N/ha in all three varieties. With increasing N application rates, curd became darker and less intense in yellow colour. Increasing rates of N application clearly posed a negative effect on ascorbic acid content. Therefore, ‘Largardo’ can be recommended as a suitable variety that produces higher yield and ascorbic acid content at 60 or 90?kg?N/ha, with the application rates lower than the commercially recommended rate (120?kg?N/ha).     

基于艺术设计理念的采摘机器人外形机构研究

为进一步实现用于农业果蔬采摘的机器人外形结构优化目标,结合当前三维可视化的艺术设计理念,针对其采摘装置结构参数与布局展开研究.考虑果蔬的物理学特性与作业周边环境光线特征,建立正确的采摘动作空间坐标,设计采摘机器人结构优化流程,从采摘臂杆的偏转角度、臂杆间距与角度阈值3个方面进行参数匹配,并综合协调各采摘关节的运动状态,...     

GPS定位测量结果坐标转换精度分析

通过对GPS控制测量数据分析,阐述了测量结果坐标转换的原理与技术,并对如何提高坐标转换精度提出了适合辽宁省地区的可行方法。     

极坐标系中具有旋转自由度的平面扇形单元

通过引进结点刚体转角，提出两具有平面内旋转自由度的平面４结点扇形单元，数值计算表明这两种单元具有很高的计算精度，为具有圆形边界的结构有限元分析提供了有效实用的单元。