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Zhu Liangsheng Sui Shifeng
Associate Professor South China Sea Institute of Oceanology Chinese Academy of Science Guangzhou Professor South China Sea Institute of Oceanology Chinese Academy of Science Guangzhou 《中国海洋工程》1997,(3)
Some researches have been made in this aspect.In the method by Walton Jr.(1992),incidentwaves are supposed to be the overlapping result of M component waves with different frequencies whichmay take different directions,the direction of incident waves should be available in advance,but in fact thedirection of incident waves is not available.In our study,incident waves are supposed to be composed ofM overlapping component waves with different frequencies,and different frequencies have different direc-tions.Based on the irregular wave reflection theory,the calculation formulas of wave direction,complexamplitude of incident waves,and complex amplitude of reflected waves in surface which are composed ofcomponent waves are derived by means of discrete Fourier transform.Then,the frequency spectra of inci-dent waves and reflected waves and the reflection coefficient of waves with corresponding frequencies areobtained.Verification of the method and the calculation results from in-situ measured data indicate thatt 相似文献
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Bacterial wilt (BW) caused by Ralstonia solanacearum is one of the most damaging diseases of potato (Solarium tuberosum L.) in Kenya and worldwide. In Kenya, potato tuber yield losses due to BW infection are estimated at 50 ~ 100%. Low soil fertility is also one of the most important constraints limiting potato production in central Kenya highlands. Farmers tackle this problem through use of inorganic fertilisers and organic manures, both of which amend the soil environment to influence bacterial wilt development. Undecomposed organic manures can also introduce the pathogen into a clean field. Between short rains 1999 and 2000, 10 on-farm extension-researcher-farmer-designed and farmer-managed trials were done at Kianjuki catchment in Embu District. The objective was to use farmers‘ participatory research approach and select the most suitable organic and inorganic fertiliser combination(s) with lowest BWI and acceptable usable tuber yields, and also to demonstrate use of some components of integrated disease management methods in reduction of disease incidence and spread. Seven treatments were proposed, presented to the farmers for discussion and the most relevant four were selected for evaluation. A newly released potato variety ‘Asante‘ was planted during the short rains 1999 and long rains 2000. BWI didn‘t result in significant differences between treatments but the tuber yields were significantly different in short rains of 1999 and 2000. During short rains 2000, both BWI and tuber yields and unusable tubers differed significantly between treatments. The results confirmed that well-decomposed manures or manures from pathogen-free areas can be used in combination with inorganic fertilisers to improve soil fertility and potato tuber yields in smallholder farms without influencing BWI. Use of certified seed tubers in pathogen free field and following recommended field sanitation measures resulted in apparently bacterial wilt free crop. Considering the high cost of inorganic ferfiliser and its negative effects on the environment, reduced usage at half the recommended rates combined with half rates of FYM is feasible option friendly to the farmer, soil and environment. The interviewed farmers also ranked the option as the most appropriate combination for soil fertility improvement for potato production in smallholder farms. 相似文献
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殷鹏莲 《测绘与空间地理信息》2021,44(4):146-147,150
设计并实现了高发性流行病管理信息系统,系统包含了数据管理、数据查询、数据统计、数据展示、系统管理五大模块,实现了合肥市区域范围内的高发性流行病病例基本情况的录入、编辑、存储和管理,数据详细信息的快速查询统计,数据成果在线展示等功能。 相似文献
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为了考虑地震波斜入射对坝后式厂房易损性的影响,通过斜入射SV波和P波波场叠加,在地表得到与实测地震动一致的设计地震动分量。同时为了考虑坝后式厂房的动力损伤,在程序中嵌入混凝土动力损伤本构,编写了可以考虑地震波斜入射体系的结构易损性分析程序。最后从太平洋地震工程研究中心(PEER)数据库中选取26条近场地震动数据,根据峰值地面加速度(PGA)对每条地震波进行调幅,以我国西南地区某坝后式厂房为工程实例,用增量动力学分析法计算了其上下游墙体在不同强度斜入射体系地震动作用下的易损性曲线。与传统垂直入射模式下的地震易损性曲线对比发现,传统垂直入射下的破坏概率较高,两种入射模式破坏概率最大相差26%。其中,坝后式厂房下游墙的破坏概率比上游墙大,最大相差可19%。因此坝后式厂房的抗震设计需考虑地震波斜入射的影响,并重点考虑下游墙部位的抗震安全性。 相似文献
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高血压病发病率预报的人工神经网络方法研究 总被引:1,自引:0,他引:1
通过统计分析,选取影响银川地区高血压病发病率的主要气象因素,将其作为输入变量经多层前馈型神经网络的BP(Back Propagation)算法进行学习训练,建立了疾病发病率的人工神经网络(ANN,Artifical Neural Net)预报模型。结果表明:该方法计算简便、误差较小,为疾病发病率预报提供了一种新的预报方法。 相似文献