Rattling vibration is an important noise source of gear-box. To controlthat noise, it is necessary to elaborate a mathematics-mechanical model on rattlinggears. In this paper, a rattling system modulated by noise was ...Rattling vibration is an important noise source of gear-box. To controlthat noise, it is necessary to elaborate a mathematics-mechanical model on rattlinggears. In this paper, a rattling system modulated by noise was investigated. Insteadof performing the very tedious numerical calculation, a discrete stochastic modeldescribed by three dimensional mean mapping was established by means of the NonGaussian closure technique. Through the example, the chaotic stochastic behaviormay be revealed. In comparison with deterministic model, the model developed inthis paper is more approximate to practice adn more available for acousticinvestigation, so that it is suggested to be applied to modeling on rattling vibration.展开更多
A lumped mass gear-rattling model with backlash is established by considering the time varying mesh stiffness,composite transmission error and the torque fluctuation.Based on the principle that no separation will occu...A lumped mass gear-rattling model with backlash is established by considering the time varying mesh stiffness,composite transmission error and the torque fluctuation.Based on the principle that no separation will occur if the response amplitude is not larger than the static response,the threshold is obtained by theoretical derivation.The validity of the theoretical derivation is verified by the numerical method.The results show that the time-varying mesh stiffness has little effect on the threshold.When the exciting frequency is less than the system natural frequency,the theoretical agrees well with the numerical one.The higher the exciting frequency or the smaller the average input torque is,the easier the separation will occur.When the exciting frequency is larger than the natural frequency by a certain value,the theoretical threshold does not agree with the numerical results.The numerical results show that the motion state will change from the meshing state to the separating state directly.The phenomenon that the gear pair sometimes separates and sometimes meshes occurs only when the exciting frequency is smaller.展开更多
Virus-induced gene silencing(VIGS)is a natural defense mechanism of plants,which can cause sequence-specific degradation of viral RNA and is often used for studying the functional genome.At present,the VIGS system med...Virus-induced gene silencing(VIGS)is a natural defense mechanism of plants,which can cause sequence-specific degradation of viral RNA and is often used for studying the functional genome.At present,the VIGS system mediated by Tobacco rattle virus(TRV)has been successfully established in many plant species.However,the VIGS system in Chinese narcissus had not been reported yet.In this paper,the first use of the TRV-VIGS system in Chinese narcissus is described in detail.By injecting pTRV2-GFP into narcissus leaves,we confirmed that TRV could infect narcissus and move in narcissus plants.After the inoculation of pTRV2-Nt PDS by two methods,phenomena such as photo-bleaching appeared in narcissus leaves and qRT-PCR results proved that PDS gene of narcissus was successfully silenced.Besides,pTRV2-NtMYB3 was inoculated into basal plates of narcissus to study the function of NtMYB3;the results showed that NtMYB3 is an inhibitor of flavonoids biosynthesis,which can increase the content of proanthocyanidins in basal plates of narcissus by repressing the expression level of NtFLS.These results indicate that the TRV-VIGS system has been successfully established in Chinese narcissus and successfully applied to the functional study of NtMYB3.展开更多
Rice sheath blight, caused by Rhizoctonia solani AG1-IA, is a major disease in rice-growing areas worldwide. Effectors of phytopathogenic fungi play important roles during the infection process of fungal pathogens ont...Rice sheath blight, caused by Rhizoctonia solani AG1-IA, is a major disease in rice-growing areas worldwide. Effectors of phytopathogenic fungi play important roles during the infection process of fungal pathogens onto their host plants. However, the molecular mechanisms by which R. solani effectors regulate rice immunity are not well understood. Through prediction, 78 candidate effector molecules were identified. Using the tobacco rattle virus-host induced gene silencing(TRV-HIGS) system, 45 RNAi constructs of effector genes were infiltrated into Nicotiana benthamiana leaves. The results revealed that eight of these constructs resulted in a significant reduction in necrosis caused by infection with the AG1-IA strain GD-118. Additionally, stable rice transformants carrying the double-stranded RNA construct for one of the effector genes, AGLIP1, were generated to further verify the function of this gene. The suppression of the AGLIP1 gene increased the resistance of both N. benthamiana and rice against GD-118, and also affected the growth rate of GD-118, indicating that AGLIP1 is a key pathogenic factor. Small RNA sequencing showed that the HIGS vectors were processed into si RNAs within the plants and then translocated to the fungi, leading to the silencing of the target genes. As a result, AGLIP1 might be an excellent candidate for HIGS, thereby enhancing crop resistance against the pathogen and contributing to the control of R. solani infection.展开更多
文摘Rattling vibration is an important noise source of gear-box. To controlthat noise, it is necessary to elaborate a mathematics-mechanical model on rattlinggears. In this paper, a rattling system modulated by noise was investigated. Insteadof performing the very tedious numerical calculation, a discrete stochastic modeldescribed by three dimensional mean mapping was established by means of the NonGaussian closure technique. Through the example, the chaotic stochastic behaviormay be revealed. In comparison with deterministic model, the model developed inthis paper is more approximate to practice adn more available for acousticinvestigation, so that it is suggested to be applied to modeling on rattling vibration.
基金This project is supported by National Natural Science Foundation of China(No.50075070).
文摘A lumped mass gear-rattling model with backlash is established by considering the time varying mesh stiffness,composite transmission error and the torque fluctuation.Based on the principle that no separation will occur if the response amplitude is not larger than the static response,the threshold is obtained by theoretical derivation.The validity of the theoretical derivation is verified by the numerical method.The results show that the time-varying mesh stiffness has little effect on the threshold.When the exciting frequency is less than the system natural frequency,the theoretical agrees well with the numerical one.The higher the exciting frequency or the smaller the average input torque is,the easier the separation will occur.When the exciting frequency is larger than the natural frequency by a certain value,the theoretical threshold does not agree with the numerical results.The numerical results show that the motion state will change from the meshing state to the separating state directly.The phenomenon that the gear pair sometimes separates and sometimes meshes occurs only when the exciting frequency is smaller.
基金the Science and technology innovation fund of Fujian Agriculture and Forestry University(Grant Nos.KFA17352A,KFA17602A)。
文摘Virus-induced gene silencing(VIGS)is a natural defense mechanism of plants,which can cause sequence-specific degradation of viral RNA and is often used for studying the functional genome.At present,the VIGS system mediated by Tobacco rattle virus(TRV)has been successfully established in many plant species.However,the VIGS system in Chinese narcissus had not been reported yet.In this paper,the first use of the TRV-VIGS system in Chinese narcissus is described in detail.By injecting pTRV2-GFP into narcissus leaves,we confirmed that TRV could infect narcissus and move in narcissus plants.After the inoculation of pTRV2-Nt PDS by two methods,phenomena such as photo-bleaching appeared in narcissus leaves and qRT-PCR results proved that PDS gene of narcissus was successfully silenced.Besides,pTRV2-NtMYB3 was inoculated into basal plates of narcissus to study the function of NtMYB3;the results showed that NtMYB3 is an inhibitor of flavonoids biosynthesis,which can increase the content of proanthocyanidins in basal plates of narcissus by repressing the expression level of NtFLS.These results indicate that the TRV-VIGS system has been successfully established in Chinese narcissus and successfully applied to the functional study of NtMYB3.
基金supported by the Henan Province Science and Technology Research Project, China (Grant No. 242102110232)the National Natural Science Foundation of China (Grant No. 31801677)the Major Program of Guangdong Basic and Applied Basic Research, China (Grant No. 2019B030302006)。
文摘Rice sheath blight, caused by Rhizoctonia solani AG1-IA, is a major disease in rice-growing areas worldwide. Effectors of phytopathogenic fungi play important roles during the infection process of fungal pathogens onto their host plants. However, the molecular mechanisms by which R. solani effectors regulate rice immunity are not well understood. Through prediction, 78 candidate effector molecules were identified. Using the tobacco rattle virus-host induced gene silencing(TRV-HIGS) system, 45 RNAi constructs of effector genes were infiltrated into Nicotiana benthamiana leaves. The results revealed that eight of these constructs resulted in a significant reduction in necrosis caused by infection with the AG1-IA strain GD-118. Additionally, stable rice transformants carrying the double-stranded RNA construct for one of the effector genes, AGLIP1, were generated to further verify the function of this gene. The suppression of the AGLIP1 gene increased the resistance of both N. benthamiana and rice against GD-118, and also affected the growth rate of GD-118, indicating that AGLIP1 is a key pathogenic factor. Small RNA sequencing showed that the HIGS vectors were processed into si RNAs within the plants and then translocated to the fungi, leading to the silencing of the target genes. As a result, AGLIP1 might be an excellent candidate for HIGS, thereby enhancing crop resistance against the pathogen and contributing to the control of R. solani infection.
