排序方式: 共有11条查询结果,搜索用时 31 毫秒
2.
在置信水平过渡中,常采取在合成不确定度σ的基础上,乘以置信因子C的方法,这种方法有时会造成置信水平失实,分析失实的原因和应注意的问题. 相似文献
3.
根瘤农杆菌介导的枸杞转化及转化植物的获得 总被引:5,自引:0,他引:5
本文报道一种重要的中药——枸杞(Lycium barbarum L.)的转化、再生系统的建立。以根瘤农杆菌(Agrobaterium tumefaciens)C58cl(pGV3850::neo1103)感染枸杞的幼茎外植体,在含卡那霉素50μg/ml的诱培养基上选择转化的愈伤组织,在含卡那霉素25μg/ml分化培养基上得到再生小芽,再生小芽中有30%外观形态正常。形态正常的小芽转到生根培养基后可长出根从而得到完整的植株。胭脂碱检测。NPT-Ⅱ活性测定及分子杂交的结果均表明,外源基因已导入枸杞并得以表达。在实验过程中还发现:(1) 经过一定预处理后,形成愈伤组织较快的外植体易被转化。(2) 转化后愈伤组织再生正常植株的频率比未转化的愈伤组织高。 相似文献
4.
A system for transformation and regeneration of Lycium barbarum L. , an important Chinese medical plant, has been established. Young stem segments from Lycium barbarum L. were infected with Agrobacterium tumefaciens C58cl(pGV3850: :ineo1130), and the transformed calli selected from the callus induction medium containing 50 fig/ml kanamycin could regenerate buds on differentiation medium containing 25 μg/ml kanamycin. 30% of the regenerated buds were normal in morphology. The normal buds could develop into whole plantlets after they were transferred to the rooting medium to induce roots. Nopa-line detection, NPT-Ⅱ enzyme activity assay and Southern blotting hybridization indicated that the foreign genes had been integrated into the genome of Lycium barbarum L. and expressed in the plant. In the processes of experiments, it was found that (i) after the pre-processes, the explants which formed callus quickly were easy to transform ; (Ⅱ) the rate of normal regenerated plants from transgenic calli was hig 相似文献
5.
地球内部密度、重力加速度与压强分布公式的拟合 总被引:3,自引:0,他引:3
李安生 《云南大学学报(自然科学版)》2007,29(5):480-484
利用地震学家布伦由地震波速度分布得出的密度、重力加速度、压强的一组典型数据,采用拟合的方法,得出了较简洁的密度、重力加速度、压强分布的近似公式.这些公式对研究地球内部的其他相关性质,具有重要的意义.
相似文献
6.
7.
摘要:
针对典型故障样本缺乏而使常规机器学习方法无法直接应用的难题,提出了一个基于支持向量数据描述(SVDD)新异类检测与基于Davies Bouldin指数(DBI)的K均值聚类方法相结合的旋转机械故障诊断框架.首先,针对正常状态样本建立SVDD模型,并利用蚁群算法对SVDD模型参数进行优化;然后,当拒绝样本数目累积到设定的阈值时,利用K均值聚类方法对其进行处理而获得能够进行标记的类别,其中,K均值聚类的类型数目由DBI辅助确定;最后,针对所标记的各类样本,分别建立SVDD模型并进行训练,将SVDD分类器按照二叉树形式构建系统状态的完整诊断模型.同时,利用滚动轴承多故障模式样本进行训练测试,以验证所提出算法的有效性.结果表明,所提出算法的训练速度为常规网格搜索算法的近10倍,DBI能够有效确定聚类的数目,对样本状态的识别率达到100%.
关键词:
蚁群支持向量数据描述; K均值聚类; Davies Bouldin指数; 旋转机械; 故障诊断
中图分类号: TP 183
文献标志码: A 相似文献
8.
李安生 《河南师范大学学报(自然科学版)》1996,24(1):85-88
本文首先讨论判定累进系统误差的常用方法“马利科夫判据”的缺陷,继而分析说明了彻底消除累进系统误差的不可能性,同时给出累进误差的定义及其判别和修正方法,最后给出修正结果的不确定度和置信度 相似文献
9.
In anther culture of Panax ginseng, its callus formation showed a wide adaptability to culture media. Large numbers of calli were induced on media exhibiting better effects of induction. Supplemeres of 5 mg 2,4-D/1 and 1 mg KT/1 to the media proved to be much effective. Regeneration of the whole plantlets from anther culture of Panax ginseng is usually quite difficult. During the past three years, however, sixteen of the 100 medium formulae tested were proved to be suitable. The formulae of MS+0.5 mg BA/1+2 mg GA/1+1000 mg LH/1+3% sucrose were considered good and effective. A visibly differentiated body, which was light-milky white and later turned into a light green spot, was formed 40 days after the callus was transferred to the differentiation media. This body differentiated subsequently into buds, roots and, eventually, seedlings. The embryoid clones have been established in order to maintain its ability of continual differentiation into plantlets through successive culturings of many generations. 相似文献
10.