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To control Monochamus alternatus and its amount of population is one of the effective ways on controlling Bursaphelechus xylophilus.The Japanese black pine which were badly harmed by M.alternatus were sprayed with the ditution from diluting fenitrothion · buprofezen 50%EC with water to 100 times, 200 times and 300 times. In this trial, the treatment is divided into two groups: one is of the different concentration but the same object (trees in the forest), the other is of the same concentration but different environmental condition (trees in the forest and felling trees indoor). Each treatment repeated five times. In the meantime, the check is not treated. After twice trial, the result indicated that the mortality rate of M. alternatus is 71.33%, 52.31% and 37.82% in the condition that trees in the forest were sprayed with the 100 times, 200 times and 300 times fenitrothion·buprofezen, and 69 69% in the condition that the felling trees indoor were spraded with 100 times fenitrothion·buprofezen, but the mortality rate of the check is only 8.92%. By this trial, it was also found that the dead adults of M.alternatus laid in the entrance of emergance hole, so enhancing the somatic character of fenitrothion · buprofezen can enhance the injury ratio of larva and pupae of M.alternatus. 相似文献
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在对四川洪雅林场柳杉长卷蛾危害调查中,发现一种柳杉长卷蛾(Homona issikii Yasuda)的捕食性天敌-短角宽扁蚜蝇(Xanthandrus talamaoi(Meigen))(食蚜蝇科Syrphidae)。该蝇在幼虫阶段取食卷蛾幼虫,捕食量日均约0.56-0.65头,蝇虫比例随害虫虫口密度增加,在林间诸种天敌中居优势地位,对抑制柳杉长卷蛾的危害具有重要作用。 相似文献
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To solve the instability problem of established sample in the neural network evaluation method for mine ventilation system, a comprehensive evaluation of the ventilation system is carried out based on rough sets and BP neural networks. Taking the ventilation system of a mine as an example, the classification quality of raw data samples are tested by using rough set data analysis system. Then, based on artificial neural network theory, a rough sets-neural network evaluation model of a mine ventilation system is established and a new rough sets-neural network evaluation method of mine ventilation system is formed. The results show that, after the model validation of data and application, its theoretical evaluation results are in line with the actual situation, and the network total error is less than 0.004. It shows that the comprehensive evaluation method based on rough sets-neural networks has a good effect in evaluating mine ventilation system in practical application. 相似文献
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四川旱耕地生产、生态问题及水土流失综合治理研究 总被引:15,自引:2,他引:15
四川地域辽阔 ,地貌以山地和高原为主 ,农耕地分布范围广 ,旱耕地比重大 ,水土流失和与之相关的旱、洪灾害等生产、生态问题突出 ,既导致农作物产量低而不稳 ,又给长江中下游带来安全隐患 ,因此 ,四川在实施西部大开发战略中 ,除实施天然林保护工程外 ,旱耕地 ,特别是旱坡耕地 (2°~ 2 5°)的水土流失综合治理 ,既具有极其重要的战略位置 ,也是四川农业持续发展不能忽视的重大问题 相似文献
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西安市雨水资源化及其利用的探索 总被引:21,自引:0,他引:21
随着城市化的发展 ,城市地表水严重污染 ,地下水超量开采 ,开发利用雨水资源已成为西安市解决水资源问题的最佳途径。雨水是宝贵资源 ,可通过多种方式实现雨水资源化 ,充分利用雨水资源以补给城市水源 ,涵养地下水 ,调节城市生态环境 ,防治雨洪灾害。对西安市区域内雨水下渗和贮存、实现雨水资源化及其利用等方面做了探索 ,并根据实际情况对西安市雨水资源化的必要性、可能性及可持续性进行了分析。 相似文献
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Based on the evolution pattern of slope deformation and failure, stability status of a slope is evaluated through analyzing the data of GPS monitoring. A neural network model of slope displacement time is developed based on the GPS monitoring data. It can be used to forecast slope deformation trends. A neural network displacement prediction model of slope deformation is proposed with Matlab ANN toolbox. Upon a case study, the ANN prediction results based on GPS monitoring data are analyzed. 相似文献