18,306 research outputs found
Crossing Lilium Orientals of different ploidy creates Fusarium-resistant hybrid
Oriental hybrid lily is of great commercial value, but it is susceptible to Fusarium disease that causes a significant loss to the production. A diploid Oriental hybrid resistant to Fusarium, Cai-74, was diploidized from triploid obtained from the offspring of tetraploid (from ‘Star Fighter’) and diploid (‘Con Amore’, ‘Acapulco’) by screening the hybrids of different cross combinations following inoculating Fusarium oxysporum to the tissue cultured plantlets in a greenhouse. By analyzing saponins content in bulbs of a number of lily genotypes with a known Fusarium resistance, it was found that the mutant Cai-74 had a much higher content of saponin than its parents. Highly resistant wild _L. dauricum_ had the highest level (4.59mg/g), followed by the resistant Cai-74 with 4.01mg/g. The resistant OT cultivars ‘Conca d’or’ and ‘Robina’ had a higher saponins content (3.70 mg/g) and 2.83 mg/g, than the susceptible Oriental lily cultivars ‘Sorbonne’, ‘Siberia’ and ‘Tiber’. The hybrid Cai-74 had a different karyotype compared with the normal Lilium Oriental hybrid cultivars. The results suggested that Cai-74 carries a chromosomal variation correlated to Fusarium resistance. Cai-74 might be used as a genetic resource for breeding of Fusarium resistant cultivars of Oriental hybrid lilies
Fault diagnosis of hydraulic motor based on mathematical morphology filter and sensitive parameters
Aiming at slipper fault diagnosis of hydraulic motor, a fusion method based on mathematical morphology and sensitive parameters is proposed. The method processes advantages of mathematical morphology filtering signals and those of high parameters’ sensitivities to slipper fault. Firstly, a slipper fault signal is filtered by morphological difference operator, and rich characteristic information can be extracted. Secondly, parameters in time and frequency domains are extracted from the signal, and morphological index which is firstly introduced into hydraulic motor fault diagnosis is also included. Lastly, after analyzing sensitivities of the parameters to slipper fault, the fault can be diagnosed effectively, and therefore the fault diagnosis methods based on parameters in time and frequency domains are further enriched
A critical review on the study of threatening in English
Despite the fact that threatening in languages is common in ordinary verbal communication, it has not received much attention from academic studies because of its “negative” nature. Muschalik’s monograph Threatening in English: A Mixed Method Approach, mainly based on the theory of Face Threatening Speech Act by Brown and Levinson (1987), takes 301 categories of threatening expressions in judicial proceedings as the corpus with qualitative and quantitative methods, brings a new perspective for pragmatic research, especially speech act research, and deepens people’s understanding of relevant issues. Initiated by Muschalik’s book Threatening in English: A Mixed Method Approach, the paper is to make a critical review on the studies of threatening in English and propose some new directions for the study of threatening in languages
Current rectification by asymmetric molecules: An ab initio study
We study current rectification effect in an asymmetric molecule
HOOC-CH-(CH) sandwiched between two Aluminum electrodes using
an {\sl ab initio} nonequilibrium Green function method. The conductance of the
system decreases exponentially with the increasing number of CH. The
phenomenon of current rectification is observed such that a very small current
appears at negative bias and a sharp negative differential resistance at a
critical positive bias when . The rectification effect arises from the
asymmetric structure of the molecule and the molecule-electrode couplings. A
significant rectification ratio of 38 can be achieved when .Comment: to appear in J. Chem. Phy
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