基于激光导航的果园拖拉机自动控制系统

为实现果园作业的自动化,以拖拉机为研究对象,采用激光导航方式实现了果园机械的自动导航。试验以激光扫描仪为检测设备对果树位置信息实时采集,采用最小二乘法规划拖拉机导航路径;拖拉机航向偏差和横向偏差作为比例控制器的输入量,以方向盘电机的转速为输出量,控制拖拉机沿导航路径直线行走;系统实现了拖拉机在果园环境下的直线行走控制功能。拖拉机以0.27 m/s的速度直线行走30 m,最大横向偏差0.15 m。试验结果表明本系统可用于果园机械的自动导航,并具有一定的可靠性。     

Qualitative Analysis of an Exponential Dynamic Neural Networks

The exponential dynamic neural network proposed.by T.D.Chiuch and R.M.Goodman in 1988 is investigated. A concise sufficient condition for the given standard patterns to bestable is presented. A one-step conversence radius of such a stable state is obtained. It is also shownthat there do not exist sporious stable states in the probabilistic sense.     

植物叶片表面结构对雾滴沉积的影响分析

为探索雾滴在不同结构叶片表面沉积效果差异,试验研究138.2、176.5、209.1、235.1和283.7μm 5个粒径雾滴在毛刺、蜡质和粗糙3种表面的沉积效果,分析了各类叶片表面在与水平面呈0°、15°、30°、45°、60°和75°6个夹角时的沉积差异。对叶面结构、叶片倾角和雾滴粒径3个因素的影响程度差异进行了正交试验。结果表明,喷量相同的情况下,雾滴在蜡质及粗糙叶面沉积率随雾滴粒径增大而减小,在毛刺叶片表面,当雾滴粒径大于231.5μm时,药液沉积率随雾滴粒径增大而减小的趋势更为明显。在毛刺和粗糙叶片表面,药液沉积率随叶面倾角增大而减小;而在蜡质叶面,倾角大于45°时,沉积率会产生一次突增并超过较小倾角时的雾滴沉积率。叶片倾角对雾滴沉积率影响最大,叶面结构次之,雾滴粒径影响不显著。     

冬小麦幼穗不同发育期不同穗段离体培养的效应

本文主要研究了四个小麦品种不同长度的幼穗及幼穗不同穗段离体培养的效应.结果:(1)取长为0.1厘米、0.3厘米的幼穗全穗、或穗长为0.5厘米的幼穗上段或下段、或穗长为1.0厘米的幼穗上、中、下三段离体培养,愈伤组织诱导率均达100％;取穗长为2厘米的幼穗上、中、下段离体培养,愈伤组织诱导率分别为34％、80％和94％;取穗长为3厘米的幼穗上、中、下段离体培养,愈伤组织诱导率分别为14％、38％和58％.(2)用长1厘米以上和长0.1厘米的幼穗高体培养,其愈伤组织主要是分化根;将长0.3～0.5厘米的幼穗愈伤组织直接转移到分化培养基上,植株分化率为78.8％     

安徽省农业信息化发展现状及对策研究

阐述了农业信息化的概念、国内外发展现状及安徽省存在的问题,探讨了安徽省数字农业建设的基础设施、机构业务、制度体制、可持续发展能力,提出了推进农业信息化的举措。     

Variation in Total and Extractable Elements with Distance from Roads in an Urban Watershed,Honolulu, Hawaii

Roads play a major role intransporting sediment associated nonpoint sourcepollutants to urban stream networks via storm drains. In urban areas the relationship of erodible soil toroads may be of critical importance in controllingmetal contributions to roads. Two 50-m transects(Park and School) were investigated perpendicular toroads in Manoa basin, Oahu, Hawaii. Concentrations ofnine elements were compared to background control soillocations and to five supplemental samples from nearbyrecreational parks. Sediment from curbside areas ofroads (road deposited sediment) was collected as thestarting point of each transect, and subsequently soilwas sampled from two depths (0–2.5 cm and 7.5–10.0 cm)along the transects. Total and 0.5 M HCl extractableconcentrations were determined for aluminum (Al),calcium (Ca), chromium (Cr), copper (Cu), iron (Fe),manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn)using either inductively coupled plasma-atomicemission spectroscopy (ICP-AES) or flame atomicemission spectroscopy (FAAS). Ca, Cu, Pb and Znexhibited anthropogenic enhancement, with Pb and Znhaving the greatest enrichment in road sedimentfollowed by locations nearest the road. Copperdisplayed a narrower band of contamination than eitherPb or Zn, and this may reflect larger aerosolassociations and more rapid fall velocities. Lead andZn exhibited substantial decay in concentration at 50 m compared to the road sediment, but enrichment wasstill apparent. The positioning of a band of soilbetween the road-curb area and the sidewalk for thePark transect facilitated deposition and storage oftrace metals, and with subsequent erosion by splash orconcentrated flow this area can account for continuedtransport of contaminated sediment to adjacent roadsurfaces. On the other hand the School transect hadno soil directly beside the road, and the nearestsample from the road (5 m) displayed enrichment butsubstantially lower than the Park transect. Thesepreliminary data suggest that remobilization of soilstored metals in close proximity to roads cansignificantly prolong the environmental contaminationof urban road systems and eventually stream sediments.     

余热排出泵叶轮流固耦合特性分析

余热排出泵长期在高温高压环境下运行,其结构的可靠性对整个机组的安全运行有着重要的影响。该文采用单向流固耦合方法研究了几种常用材料及增加叶轮盖板厚度对转子结构动力学特性的影响,同时对比了常温和高温下叶轮的振动特性。结果表明,余热排出泵高温运行时,叶轮的第1阶固有频率为394.17 Hz,较常温下升高了2.28%,远高于叶轮叶片通过频率。在各阶模态振型下,1Cr13MoS叶轮固有频率最大,ZG225-450叶轮固有频率最小。设计工况和偏工况下叶轮的应力及变形变化趋势基本一致,叶轮的变形随半径的增加而不断增大,最大变形量出现在后盖板叶轮出口处。叶轮的应力分布不均,最大应力均出现在叶片尾缘与后盖板接合处。沿着前盖板和叶片接合线,应力的峰值随前盖板厚度增加而减小。沿着后盖板和叶片接合线,增加后盖板厚度明显减小了应力峰值。高温和常温应力变化趋势基本一致,但是高温下叶轮应力明显高于常温。尤其在叶轮进口处附近,高温应力相对于常温应力增加超过300%。该研究结果为下一步进行更加复杂的动力学分析、疲劳分析以及结构优化提供参考。     

利用高压静电场保鲜鸡蛋试验

为探讨高压静电场对鸡蛋贮藏保鲜的影响,该试验利用30、60、90 kV/m不同高压静电场分别对鸡蛋进行30和60 min的预处理,然后置于13℃左右的室温条件下贮藏,定期测定鸡蛋的哈夫单位、蛋黄指数、挥发性盐基氮和感官性状的变化等指标,研究高压静电场对其贮藏保鲜效果的影响。试验结果表明：高压静电场处理能很好地保持鸡蛋内部的含水量;有效地降低了哈夫单位、蛋黄指数与挥发性盐基氮的变化速率;贮藏保鲜效果明显好于对照。该试验30 kV/m、60 min剂量和60 kV/m、30 min剂量的处理,保鲜效果最好。     

Ultra High-Performance Liquid Chromatography with High-Resolution Mass Spectrometry Analysis of African Mango (Irvingia gabonensis) Seeds, Extract, and Related Dietary Supplements

Dietary supplements based on an extract from Irvingia gabonensis (African mango, AM) seeds are one of the popular herbal weight loss dietary supplements in the U.S. market. The extract is believed to be a natural and healthy way to lose weight and improve overall health. However, the chemical composition of AM-based dietary supplements (AMDSs) has never been reported. In this study, the chemical constituents of AM seeds, AM seeds extract (AMSE), and different kinds of commercially available AMDSs have been investigated using an ultra high-performance liquid chromatography with high resolution mass spectrometry method. Ellagic acid, mono-, di-, and tri-O-methyl-ellagic acids, and their glycosides were found as major components in AM seeds. These compounds may be used for quality control of AM extract and related dietary supplements.     

应用模糊c均值聚类获取土壤制图所需土壤-环境关系知识的方法研究

在没有土壤普查专家及土壤图的地区,获取土壤环境间关系的知识是基于知识进行预测性土壤制图中的关键问题。本文建立了一套应用模糊c均值聚类(Fuzzyc-means,FCM)获取土壤环境间关系知识的方法:得到对土壤形成发展具有重要作用的环境因子,建立环境因子数据库;对环境因子进行模糊聚类,得到环境因子组合隶属度分布图;根据隶属度值确定野外采样点;将环境因子组合与土壤类型对应,进而提取土壤-环境关系知识。为检验该方法的有效性,应用所得知识进行土壤制图,通过独立采样点对土壤图进行精度评价。本文在黑龙江鹤山农场一个研究区的应用结果表明,该方法仅需要少量的野外采样即可获得有效的土壤-环境关系知识,为预测性土壤制图提供必需的依据,同时也显著提高了野外采样的效率。