基于小波变换的华北平原耕地复种指数提取

该文以中国华北平原为研究区域,提出了基于小波变换的耕地复种指数遥感提取方法。首先,利用小波变换对2007年36景SPOT VGT/NDVI（SPOT VEGETATIONVGT数据归一化植被指数）遥感数据进行去噪处理,重建耕地农作物生长NDVI（归一化植被指数）曲线;然后,结合地面样点数据、农时数据和农业统计数据,采用二次差分法提取了华北平原2007年耕地复种指数和空间分布特征。研究结果表明,华北平原5省市耕地复种空间分布存在明显的地域特性,河南省耕地复种指数最大,达到179.4%,山东省次之,北京市最小。该研究结果与统计数据和其他遥感监测比较结果表明,基于小波变换去噪时序遥感数据提取耕地复种指数的技术方法与统计数据和其他遥感监测结果总体上具有较好的一致性,复种指数空间分布变化趋同。     

基于照度-反射模型的脐橙表面缺陷检测

水果表面缺陷是影响水果价格最主要的因素之一,目前大部分研究基于静态图像采用较复杂的算法分割水果表面缺陷。该文介绍了一种基于在线水果图像的表面亮度均一化校正及单阈值缺陷分割方法。首先,通过RGB颜色空间转换获取HIS空间图像的色调（H）分量,基于H分量建立掩模对RGB图像的R分量执行掩模去背景;然后,基于照度-反射模型,利用低通滤波获取R分量图像的亮度分量,利用此亮度分量对去背景后的R分量图像进行亮度校正;最后,利用一个简单的阈值对亮度校正后的图像进行缺陷分割。利用此算法,对416幅图像的检测结果表明总体检测正确率超过99%。该方法简单、有效,在在线水果缺陷检测中具有较大的应用潜力。     

Isolation Properties of Plane SH Wave by Double row Rigid Pile Barriers

Based on Twerskys theory, with the multiple scattering of plane acoustic or electromagnetic waves by an arbitrary configuration of parallel cylinders, a new method differing from the conventional ones is developed to figure out the plane SH waves scattered by rigid piles to solve the problem of the environmental vibration isolated by pile rows. This new method eliminates the disadvantages of the single scattering hypothesis which does not consider the coherent phase relations between the waves. Also, the influence factors on screening effectiveness including the orders of scattering, the space between pile rows and separations between the adjacent piles are investigated.     

Effectiveness of combining resistance to Thielaviopsis basicola and Tomato spotted wilt virus in haploid tobacco genotypes

Black root rot (BRR) caused by Thielaviopsis basicola as well as Tomato spotted wilt virus (TSWV) are the most serious problems in tobacco growing regions. We crossed the breeding line WGL 3 carrying BRR resistance derived from N.glauca with the line PW-834 the resistance of which to TSWV was transferred from cultivar Polalta. Anthers obtained from F₁ hybrid plants were cultured to induce haploids combining resistance to Th. basicola and TSWV. Flow cytometry analysis revealed 242 haploids and 2 spontaneous doubled haploids among regenerants. All haploids were cloned and then evaluated for BRR as well as TSWV resistance. The presence of pathogens was detected by microscopic evaluation of roots or using DAS-ELISA test. Microscopic assessment showed that, 132 haploids had no symptoms of Th. basicola which, together with the absence of symptoms in the F₁ hybrids, indicated a dominant monogenic mode of inheritance. At the same time only 30 haploids demonstrated resistance to TSWV. SCAR markers associated with TSWV resistance gene detection was applied. The results indicate that small proportion of TSWV-resistant haploids is probably due to the influence of deleterious genes flanking the resistance factor that reduced vitality of gametophytes. Altogether, 24 haploids showed multiple resistance to Th. basicola and TSWV.     

多级离心泵性能的探讨

综合考虑了离心水泵的水力损失、容积损失和机械损失,通过实验提出了影响多级离心泵性能的因素,揭示了离心泵使用效率与各因素的关系,为高效使用多级离心水泵提供了理论依据和方法。     

临济管道保温层应用的可行性分析

根据临济管道的设计输量和胜利进口混合原油的物性,对管道无保温层和增设保温层两种工艺进行了综合热力计算,并结合临济管道沿途区域的地质条件,分析比较了无保温层管道与增设保温层管道所消耗的热费用、建设费用及减少的热站投资,结果表明,临济埋地原油管道增设保温层在技术上是可行的,但保温结构的选用还应综合考虑打孔盗油等人为的破坏因素.     

临夏北塬区持续农业的局势分析与决策

以临夏北塬区45个农户为研究对象,经聚类分析该区农业生产可划分为:种养型,养种型和综合型三类;以产值、收入和效益为决策目标,运用多目标局势决策理论,分析了各类型的现状与优势,以此为基础,构建了该区农业持续发展的优化结构。     

直埋敷设与地沟敷设在供热工程中的应用研究

通过对高密度聚乙烯保护层的聚氨酯保温直埋管和玻璃棉类保温管地沟敷设工程造价、不同保温材料热损失进行计算比较 ,结果表明 :使用聚氨酯保温直埋管可降低工程造价 8% ,管网热损失仅为 2 % ;采用高密度聚乙烯保护层的聚氨酯保温管道使用寿命是地沟敷设管道的 3～ 4倍 ,施工周期可缩短 5 0 %。并对聚氨酯保温管直埋敷设的施工和设计提出了一些建议。     

一个农药连锁店业务数据转化为植保信息的模型

农业现代化的发展，要求进一步提高植保信息预测的准确性和及时性，作为传统信息采集、汇总、分析方法的补充，对农药连锁店管理信息系统业务数据进行深加工并加以利用，转化为农业植保信息，是利农、利产的事，并且为加强病虫害预测提供了一个全新的思路。