农田非结构特征视觉导航研

研究了农田非结构环境下,通过机器视觉提取导航线的处理算法.首先,根据农作物的特点提出了使用聚类的方法检测作业区域终点;其次,为避免噪声干扰,利用移动窗口检测二值图像白色像素的个数,确定导航路径区域;最后,使用改进的Hough变换提取导航线.实验表明,该算法可以准确提取绿色植物的行信息,处理一帧分辨率为320×240像素的彩色图像平均需要57.404ms,正确识别率达99%.     

盐碱胁迫下羊草消减文库的构建及分析

以盐碱胁迫下的羊草地上部分cDNA为实验方(tester),非盐碱条件下生长的羊草地上部分cDNA为消减方(driver),利用抑制性消减杂交技术(suppression subtractive hybridization,SSH)构建了盐碱胁迫下羊草消减文库.从消减文库中筛选1920个阳性克隆,PCR鉴定插入片段大部分集中在300～800 bp之间.将聚类后得到的552个非重复序列与GenBank中的序列进行比对,其中有548条与数据库中的序列有同源性,其中功能已知的339个,功能未知序列209条.获得了与盐碱胁迫相关的基因,如单脱氢抗坏血酸还原酶(MDAR)、γ-谷氨酰半胱氨酸合成酶(γ-ECS)、铁蛋白(Ferrtin)、水孔蛋白(PIP)、脱水素基因(dehydrin)、14-3-3蛋白等.本实验为抗逆基因的克隆及系统研究盐碱胁迫下羊草相关基因的表达奠定了基础.     

黄旗海水环境质量现状评价

在对黄旗海1999年、2000年和2001年水质监测的基础上,选用LogisticCurve(L-C)水环境质量综合评价模型,以等级评价标准和均匀随机数产生建模样本和验证样本,利用实码加速遗传算法求解评价模型,对黄旗海水环境质量的富营养化进行了现状评价,确定了1999年、2000年和2001年黄旗海的富营养化等级。结果表明:黄旗海1999年、2000年和2001年水质的富营养化程度都处于4级富营养和5级极富营养之间,富营养化等级大小依次为:1999年>2001年>2000年。     

The Ecological Environment of Chinese Traditional Dwelling_Houses

This paper gives some analyses on the indoor climate and air quality in Chinese traditional quadral yard Buildings.A conclusion has been drawn that the living environment created by quadral yard building is of high quality.This kind of building is of great referential value in building human settlment environment with sustainable developmenlt and can also help to creat a better architectural form fitted in with the natural environment.     

Effect of two wheat genotypes and Swedish environment on falling number, amylase activities, and protein concentration and composition

Variation in falling number, amylase activities, protein concentration and composition were investigated in two wheat cultivars grown in Sweden over two seasons, in four locations, with four N fertilizer rates, with and without fungicide treatment. The results showed that;

基于SD变化环境下农业水资源供需平衡模拟

为了探讨变化环境对农业水资源供需平衡的影响,运用系统动力学软件Vensim-Dss建立了农业水资源供需平衡的系统动力学模型,综合考虑社会经济发展和气候变化情景,仿真模拟了变化环境下农业供、需水量及缺水量的变化情况.石羊河流域模拟结果表明:未来农业供水量和需水量受气候变化的影响程度不同,但 2033年以后,农业供水量在不同气候变化情景下的变化趋势相同;不同行政区农业水资源系统对气候变化的响应存在明显差异,金昌市A2气候情境缺水率大于B2情景,在2029年、2038年缺水率分别达到32.0%,28.6%, B2情境下,2021年开始出现轻度缺水,中度缺水年仅出现在2023年和2039年,缺水率分别为30.7%,30.5%;武威市A2气候情境下缺水率小于B2情景,仅2038年为中度缺水,缺水率为24.9%,B2气候情景中度缺水年较多,2023年缺水率最大,达到33.2%.研究结果可以对变化环境下区域用水规划和农业发展规划提供指导.     

苦瓜主要经济性状的遗传及其与环境互作效应

 利用加性-显性与环境互作遗传模型, 分析了7个苦瓜亲本及其21个F1代在春、秋两个栽培 季节8个经济性状的数据, 估算了各项遗传方差分量。结果表明, 单株前期产量(单株前产) 、单瓜质量、果实纵径、果实横径、果肉厚和果形指数等6 个性状主要由加性效应控制, 加性方差的比率分别为45.2%、70.7%、89.4%、38.1%、41.2%和22.0% , 均达极显著水平; 单株产量和单株结果数则以加性×环境效应占优势(加性×环境方差的比率分别为24.5%和38.1% ) 。除单株结果数外, 其余性状的普通狭义遗传率和普通广义遗传率均达到极显著水平; 单株结果数的互作狭义和互作广义遗传率最高, 也达到了极显著水平。     

Logging pattern and landscape changes over the last century at the boreal and deciduous forest transition in Eastern Canada

Forestry practices associated with the industrial era (since ~1900) have altered the natural disturbance regimes and greatly impacted the world’s forests. We quantified twentieth century logging patterns and regional scale consequences in three sub-boreal forest landscapes of Eastern Canada (117,000, 49,400 and 92,300 ha), comparing forestry maps depicting age and forest cover types for early industrial (1930) and present-day (2000) conditions. Results were similar for the three landscapes, indicating large-scale forest change during the twentieth century. In 1930, previous logging activities had been concentrated in the lowlands and along the main hydrographical network, as compared to a more even distribution over the landscapes in 2000, reflecting a decreasing influence of the environmental constraints on forest harvesting. In 1930, old-aged forests (>100 years) accounted for more than 75% of the unlogged areas of the three landscapes, as compared to less than 15% for the present-day conditions. Logging practices have thus inverted the stand age distribution of the landscapes that are currently dominated by young and regenerating stands. The 1930 forest cover types showed a clear relationship with elevation, with conifers located in the lowlands and mixed and deciduous stands restricted to the upper slopes. Between 1930 and 2000, 58–64% of the conifer areas transformed to mixed and deciduous forests, such that no clear altitudinal relationships remained in 2000. We conclude that twentieth century logging practices have strongly altered the preindustrial vegetation patterns in our study area, to the point that ecosystem-based management strategies should be developed to restore conifer dominance, altitudinal gradients, as well as the irregular structure inspired from old forest stands.     

天津市园林病虫害无公害防治及生态环境效益分析

研究天津市园林植物病虫害的无公害防治技术,比较分析无公害综合防治技术对保护本市生态环境所发挥的重要作用及所产生的生态环境效益,提出进行园林植物保护的无公害防治的系列技术与措施。此成果的应用推广,进一步推动本市园林病虫害的无公害可持续防治,并为天津市城市生态环境的改善做出重要贡献。     

农业车辆视觉实际导航环境识别与分

分析了对路径识别影响较大的变光照环境、杂草环境和阴影环境对农业车辆导航路径的影响,提出一种实际环境中的农业车辆视觉导航研究方法,即先采用神经网络算法对农田环境进行自动分类,然后再相应的选择不同的路径识别方法进行处理.环境识别与分类试验结果证明,该方法能够提高农业车辆视觉导航系统的实用性和可靠性,导航环境的分类准确率为95%,单幅图像平均耗时23 ms.