排序方式: 共有19条查询结果,搜索用时 625 毫秒
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吴勃英 《湖南农业大学学报(自然科学版)》2000,27(2)
在再生核空间W^2 2(0)中,给出在动力系统等领域广泛应用的中立型二阶常延迟微分方程组数形式的解析解表达式,当解析解级数截断时得到近似解,并分析了此近似解的特点。 相似文献
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L. Tusell P. Pérez‐Rodríguez S. Forni D. Gianola 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2014,131(2):105-115
Predictive ability of yet‐to‐be observed litter size (pig) grain yield (wheat) records of several reproducing kernel Hilbert spaces (RKHS) regression models combining different number of Gaussian or t kernels was evaluated. Predictive performance was assessed as the average (over 50 replicates) predictive correlation in the testing set. Predictions from these models were combined using three different types of model averaging: (i) mean of predicted phenotypes obtained in each model, (ii) weighted average using mean squared error as weight or (iii) using the marginal likelihood as weight. (ii) and (iii) were obtained in a validation set with 5% of the data. Phenotypes consisted of 2598, 1604 and 1879 average litter size records from three commercial pig lines and wheat grain yield of 599 lines evaluated in four macro‐environments. SNPs from the PorcineSNP60 BeadChip and 1447 DArT markers were used as predictors for the pig and wheat data analyses, respectively. Gaussian and univariate t kernels led to same predictive performance. Multikernel RKHS regression models overcame shortcomings of single kernel models (increasing the predictive correlation of RKHS models by 0.05 where 3 Gaussian or t kernels were fitted in the RKHS models simultaneously). None of the proposed averaging strategies improved the predictive correlations attained with single models using multiple kernel fitting. 相似文献
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倪金霞 《金陵科技学院学报》2014,(3)
利用再生核空间和傅立叶变换的性质,构造了 W 12(R )空间的再生核,讨论了该再生核与微分方程的关系,并给出了 W 12(R )空间的几个不等式。 相似文献
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The reproducing kernel particle method (RKPM) is a typical meshless method based on kernel function simulation. Based on the interpolating shape function of RKPM and Mindlin plate theory, the governing equations of RKPM to the deflection solution of Mindlin plate bending on a Winkler elastic soil foundation are established. Numerical results indicate that the above method and the corresponding program are effective and accurate. 相似文献
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日本鳗鲡(Anguillajaponica)产后亲鱼的恢复培养全过程包括:产后亲鱼的海水淡化、诱导开口以及亲鱼培育。对2种不同淡化方式的结果比较发现,日本鳗鲡亲鱼的海水淡化方式以缓慢连续的方式较好,即每天换水1次,每次淡化量为总盐度的3%~4%,总淡化时间为1个月。淡化后的亲鱼存活率分别为:自然产卵的产后亲鱼达到100%,人工授精的产后亲鱼为86.3%,而难产的产后亲鱼则为81.5%。在各种开口驯养方式中,以水蚯蚓为开口饵料的驯养效果较好。诱导亲鱼开始摄食所需时间最短,为18d;摄食量也最大,达到平均体重的2.5%。从水蚯蚓逐步转为全人工饵料后,进行日常亲鱼培育。经18个月的恢复培养后,使产后亲鱼的平均体重雌鳗330g、雄鳗150g分别恢复到765g和470g。但2次繁殖的各项指标中,催熟率、成熟系数和性腺发育情况远远低于野生鳗,而催产率和幼苗存活率则略高于野生鳗,其原因尚有待进一步研究。 相似文献
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周传世 《湖南农业大学学报(自然科学版)》1989,16(1)
本文得到了加权Bergman空间L_(aa)~2(D)上面的Hankel算子的有界性和紧性的充要条件。 相似文献
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不同培养基对草莓茎段快速繁殖的影响 总被引:1,自引:0,他引:1
选用6种培养基,进行了草莓茎段快速繁殖实验。结果表明,其最佳培养基是MS+2.0mg/L BA 0.1mg/L IAA。 相似文献