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91.
N periodic multiresolution analysis with band M was introduced. By means of Fourier transformation and inner-product, N periodic orthogonal muhiresolution analysis with band M was studied. Expression of its scaling function space in frequency domain is obtained, the coefficients relationship of lowpass filter and highpass filter is investigated, and the elementary property of its mask is worked out. The results show that filter and mask of periodic wavelet is a series of coefficients. 相似文献
92.
93.
提出了一种光谱异质性参数优化方法,与现有方法相比,新方法的改进主要有:①在设置参与分割的波段数据时,通过引入派生波段数据来增强分割判据的数据支撑;②在设置各波段数据层的权值时,综合考虑了各波段数据层包含的信息量和相互间的信息相关度,以抑制波段数据层间的信息冗余对分割过程的不利影响.最后,通过分割对比实验证明:采用新方法设置的光谱异质性参数执行影像分割,“欠分割”现象有了较大幅度地减少,对象间的差异程度和对象内部的均质程度都得到了提高,分割质量有了明显地改善. 相似文献
94.
【目的】分析动荷载条件下黄土局部化变形的判断依据和剪切带的特性,探究不同初始应力条件对非饱和黄土剪切带特性的影响。【方法】用动扭剪仪进行陕西杨凌非饱和黄土的动变形试验,分析其动本构关系曲线、动孔隙气压力和阻尼比的变化规律,探讨初始平均主应力和初始主应力方向角对剪切带倾角的影响。【结果】土样的动本构关系曲线、动孔隙气压力随时间变化曲线和阻尼比随动剪应变变化曲线皆为非线性型,其变化规律很好地体现了局部化变形的过程。当初始主应力方向角<45°时,土样的剪切带倾角随着初始平均主应力的增加而呈增加趋势;当初始主应力方向角≥45°时,剪切带倾角随着初始平均主应力的增加呈减小趋势。在初始主应力方向角<45°时,剪切带倾角随着初始主应力方向角的增大而减小;当主应力方向角为90°时,土样未出现剪切带。【结论】动荷载作用下,黄土会发生局部化变形,这种局部化变形的出现和发展可以用动孔隙气压力和阻尼比的变化规律来判别,该判别方法意义明确且合理可行;初始平均主应力、初始主应力方向角对黄土的剪切带倾角有一定影响。 相似文献
95.
刘贵斌 《大连水产学院学报》1998,13(4):52-55
利用单片机控制技术,将单边带电台和GPS这两台功能不同的设备进行综合控制和管理,使单边带电台自动报发船位及数字通讯,从而收到以较小的投入,达到扩展功能,提高自动化程度和管理水平之功效。 相似文献
96.
Agronomic evaluation of precise mechanical hoeing and chemical weed control in sugar beet 总被引:1,自引:0,他引:1
Most herbicide applications to sugar beet (Beta vulgaris L.) are made to the whole crop area, but there is the opportunity to restrict applications to the crop row, decreasing the usage of herbicide by up to 70%. However, this would require greater use of mechanical weed control between rows. Experiments were performed in two seasons to evaluate the weed control performance of a novel, vision‐guided, inter‐row hoe in sugar beet crops grown on a peat fen soil. Hoe lateral placement was within ±30 mm. A precise hoeing and band spraying treatment was compared with overall herbicide use, and with treatments in which the herbicide applications were replaced by hand weeding to minimize competition between crop and weeds. Two hoe passes were made in each season, at crop growth stages of two and 10–12 true leaves in the first season and four and eight true leaves in the second season. Plant population density was not affected by treatment, indicating that none of the treatments caused crop plant loss. Use of the guided hoe controlled weeds better than overall spraying. Crop yields were not significantly different between treatments, indicating that weed control prevented competition with the crop in all treatments. 相似文献
97.
Funda Oskay Zeynep Tunalı Asko T. Lehtijärvi Hatice Tuğba Doğmuş-Lehtijärvi Steve Woodward Martin Mullett 《Plant pathology》2020,69(8):1551-1564
Dothistroma needle blight (DNB) is a serious disease of the Pinaceae, mainly Pinus species, caused by the fungi Dothistroma septosporum and D. pini. Both species are regarded as invasive forest pathogens worldwide, with rising incidence in central and northern Europe over the last three decades. In this work, 29 sites were investigated between 2013 and 2015 in south-western Turkey. Morphological examination of needles confirmed DNB infection (i.e., Dothistroma conidiospores observed) at 18 sites, and a total of 108 Dothistroma sp. isolates were obtained from 11 of the sites. Host age seemed to be an important factor in both occurrence and severity of DNB in Pinus brutia forests. Continuous rainy days, especially in December, may increase severity of disease; however, extreme rain events may reduce available conidiospores on plant tissues or in the air. Species-specific mating type primers showed that all isolates were D. septosporum; D. pini was not detected. The mating type ratio was close to 1:1, indicating sexual recombination was occurring. Eleven microsatellite markers revealed 59 unique multilocus haplotypes (MLHs) among the 73 isolates originating from different conidiomata. The majority of MLHs were represented by a single isolate (n = 52) and only one MLH was shared between two localities. Analyses showed high genetic diversity, isolation-by-distance, and clear population clusters. These findings suggest that D. septosporum is well established in south-western Turkey and is probably not a recent introduction. 相似文献
98.
Kensuke Ito 《Journal of Forest Research》1999,4(2):151-156
To understand factors involved in tree-size dependent vulnerability ofCryptomeria japonica to damage bySemanotus japonicus, residence of adultSemanotus japonicus on host trees was assessed in twoCryptomeria japonica stands, using band trap method and mark-recapture techniques. Adult capture distributions among trees were analyzed in relation
to diameter size of each tree. Female adults consistently exhibited more frequent residence on larger trees, under different
field conditions. Females that made inter-tree movements preferentially chose larger trees as their destinations. Frequent
residence by females on large trees was associated with high productivity of progeny adults. Male adults were also more frequently
resident on larger trees. These results suggest that tree-size dependent oviposition accounts for the tree-size dependent
vulnerability ofCryptomeria japonica to damage bySemanotus japonicus. Possible causes underlying the differential host residence of adultSemanotus japonicus are discussed. 相似文献
99.
普通小麦醇溶蛋白组份的分布及其与HMW——麦谷蛋白亚基对品质的组合效应 总被引:6,自引:1,他引:5
本研究利用SDS-PAGE和改良的APAGE技术分析了1124份普通小麦材料的HMW—麦谷蛋白亚基和麦醇溶蛋白谱带的组成,共分离出18种主要的HMW麦谷蛋白的等位变异和67条不同迁移率的醇溶蛋白潜带。根据多元回归分析,筛选出gli42.3,62.7,39.6(2),11.4,23,Glu 5 10等蛋白谱带对以沉降值为代表的面包烘烤品质起增效作用。品种间品质性状变异的28%~42%可以由两种蛋白组份的差异所决定,而一种蛋白组份只能决定12.3%~31.0%。国内品种中优质谱带少,非优质谱带比例高,这可能是造成我国小麦面包烘烤品质差的原因之一。提出在后代选育中要立足于优中选优,避免非优质谱带组合的出现。按高效谱带做第一次分类效果最好。此外,对这两项生化技术在品质育种中的应用进行了讨论。 相似文献
100.