基于DEM的重庆三峡库区流域水系提取研究   总被引：1，自引：0，他引：1       下载免费PDF全文

俞雷  刘洪斌  武伟 《西南大学学报(自然科学版)》2006,28(2):215-218

以重庆三峡库区为研究对象,论述基于数字高程模型提取流域水系的方法、原理。应用“Burn-in”算法,对DEM进行再处理,即将发生河道偏差的平坦区域上的实际河网叠加到DEM中,对河道及河道两侧所在栅格单元高程值进行修正,重新生成流域河网。在原有DEM不作较大修改的前提下,使得生成的河网与实际河网更加匹配,同时也保证了模拟结果的准确性。  相似文献   

A modified critical test and its use in two dose titration trials to assess efficacy of praziquantel for Anoplocephala perfoliata in equids     

Slocombe JO 《Veterinary parasitology》2006,136(2):127-135

Aims of this study with 43 equids naturally infected with Anoplocephala perfoliata in two dose titration trials were to document (i) the usefulness of a critical test with a 48 h treatment to necropsy period, (ii) efficacy of an oral paste of 0.5-2.0 mg praziquantel/kg body weight, and (iii) when after treatment would fecal egg counts provide best estimates of the tapeworm's prevalence in a herd. All feces passed by an equid after treatment and collected in successive 12 h batches were examined for tapeworms. At necropsy, tapeworms were identified as attached to the mucosa or unattached. Tapeworms were examined with a stereoscope and identified as normal or abnormal. Fecal samples were taken for egg counts at treatment and at 6 h intervals thereafter. In 32 of 36 treated equids, efficacy was 100% and mean efficacies for 0.5, 1.0, 1.5 and 2.0 mg praziquantel/kg body weight were 85.5, 99.7, 100 and 100%, respectively. Two equids treated with 0.5 mg praziquantel/kg body weight had low efficacies (5.4 and 38.1%) and normal tapeworms were found attached in the ventral colon and in one equid also in the dorsal colon. In seven untreated equids, tapeworms were primarily in the cecum with 21.3% detached. "Major fragments" or worms without a scolex but otherwise nearly a complete worm were 20.5% of the number of intact worms; they were not included in the efficacy analysis but should be. If the two equids with low efficacy were eliminated and if the number of all tapeworms and major fragments are combined less than 0.5% were in feces within 12 h of treatment, about 20% were in the 12-24 h period, 42% in 24-36h, 24% in 36-48 h and 13.5% in the equids at necropsy. One horse passed all its tapeworms in 24 h. This 48 h test when compared with a 24 h one with no examination of feces was more efficient in use of trial animals and reduced underestimation and overestimation of efficacy. However, a protocol similar to the 48 h test but with a 24 or 36 h post-treatment period should be investigated. The mean egg count peaked 18-24 h after treatment and samples taken at that time would provide the best estimate of prevalence. The Cornell-Wisconsin centrifugal flotation technique had a specificity of 100% and at 18 and 24 h its sensitivity was 94%. A brief discussion on critical and controlled tests for assessing efficacy of an anthelmintic for A. perfoliata is presented.  相似文献   

自动电位滴定法在果蔬汁饮料总酸度测定中的应用   总被引：1，自引：0，他引：1  

李艳霞  谢东坡  任凯 《安徽农业科学》2009,37(36):18155-18156

[目的]采用自动电位滴定法测定果蔬饮料总酸度。[方法]首先采用自动电位滴定法确定不同果蔬汁的滴定终点,再根据确定的滴定终点,采用自动电位滴定法测定不同果蔬汁的总酸度。[结果]该法测定果蔬汁饮料中的总酸度,操作步骤简便,测定准确度较高,可用于实际果蔬汁饮料总酸度的测定。[结论]该研究为自动电位滴定法在果蔬汁饮料总酸度测定中的应用奠定了基础。  相似文献   

自动滴灌系统的设计与实现   总被引：1，自引：1，他引：0  

董加强  宋敦波  施智雄 《安徽农业科学》2009,37(20):9649-9650

设计了一种自动滴灌系统,并介绍了该系统的总体结构、控制过程、传感器电路和沙漠植树过程中滴灌的自动控制。  相似文献   

烟叶烘烤自动控制系统的研究   总被引：1，自引：1，他引：0  

范智平  卢博友  张保健  乔晓娟 《安徽农业科学》2009,37(27):13241-13242

以80296SA为控制核心,采用预测模糊控制方法实现了烤烟过程中的温度控制及湿度检测。并通过实际应用验证了该方法的有效性与合理性。  相似文献   

智能农业：一种通向成功的新方式     

Hans W Gripentrog 《农业工程》2012,2(3):88-89

当今,精准农业技术已经越来越受到重视,同时随着劳动力成本的提高,越来越多的新技术新设备摆在了农民面前,如何将大量信息数据进行整合应用成为了摆在农民面前的问题。智能农业正是在这种情况下提出的。该文从6个方面介绍了智能农业的概念、发展方向以及目前应用状况,同时也阐明了发展中存在的问题。  相似文献   

佳多农林病虫害自动测控系统(ATCSP)开发与应用前景     

赵树英 《农业工程》2012,(Z1):51-53

佳多农林病虫害自动测控系统集成了病虫害实时监测预警、预警遥控和频振生物诱控3个子系统,通过信息化管理、自动化控制和无害化防治,为有效解决农林害虫防控依赖化学农药这一世界性难题奠定了技术基础。  相似文献   

基于PLC的食品真空冷冻干燥机的控制     

邱桐  徐光  李新秋 《安徽农业科学》2011,(19):11971-11972,11986

介绍了食品冷冻干燥机的控制系统的结构,提出了PLC应用于控制系统的实现方案,并设计出上位机监控软件的方法,使系统具有较高的自动化程度和可靠性。  相似文献   

Development of plaque assay for Chilean Infectious Salmon Anaemia Virus,application for virus purification and titration in salmon ASK cells     

M T Castillo‐Cerda  L Cottet  D Toro‐Ascuy  E Spencer  M Cortez‐San Martín 《Journal of fish diseases》2014,37(11):989-995

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蔬菜大棚温度自动控制系统设计     

冯程程  龚希武  刘要 《安徽农业科学》2017,45(22)

随着现代化温室技术的发展与应用,以及人们对反季节蔬菜的庞大需求,温室在反季节蔬菜的培育中发挥着显著的作用,成为相关技术人员的关键课题之一。我国蔬菜大棚还处于发展的初期阶段,而国外的蔬菜大棚系统虽然趋于完善,但其经济性和适应能力却有待商榷。因此,需要创造一种基于我国环境的价格亲民、操作简单、功能稳定的现代化蔬菜大棚自动控制系统。通过对蔬菜大棚自动控制系统特性的分析,设计了基于可编程逻辑控制器(PLC)的蔬菜大棚温度数字化智能控制(PID)的自动控制系统。PLC将各种传感装置勘测的变量实时检测数据,通过和设定参数比较,对大棚内的温度进行调节。对系统进行仿真测试显示,该蔬菜大棚温度自动控制系统已经基本达到了控制目标,控制相对稳定可靠,具有较高的经济性。  相似文献