Single spore isolation is a fundamental approach in plant pathology and mycology to isolate and identify plant fungal pathogens from diseased samples.However,routine single spore isolation procedure is time-consuming ...Single spore isolation is a fundamental approach in plant pathology and mycology to isolate and identify plant fungal pathogens from diseased samples.However,routine single spore isolation procedure is time-consuming and has a high risk of contamination by other microorganisms.In this study,we developed a rapid approach for isolating a single spore of the fungal pathogen,Pyricularia oryzae,from rice blast diseased leaves in the paddy field with low potential of contamination.First,rice blast leaves with single lesions were selected in the paddy field,and a single lesion was cut out and pressed and dragged gently across the surface of water agar.Next,a germinated single spore with a barely visible piece of agar was cut out of water agar with a dissecting needle under a stereomicroscope at approximately 120-fold magnification.Last,the germinated single spore with water agar was transferred onto oatmeal tomato agar for growth and preservation.Based on our experience,a skilled technician or student can successfully isolate single spore from over 150 independent diseased samples with nearly no contaminations in a single working day.This approach is also suitable for isolating single spore from other fungal disease samples that produce abundant aerial conidia.展开更多
The blast-induced ground vibration prediction using scaled distance regression analysis is one of the most popular methods employed by engineers for many decades. It uses the maximum charge per delay and distance of m...The blast-induced ground vibration prediction using scaled distance regression analysis is one of the most popular methods employed by engineers for many decades. It uses the maximum charge per delay and distance of monitoring as the major factors for predicting the peak particle velocity(PPV). It is established that the PPV is caused by the maximum charge per delay which varies with the distance of monitoring and site geology. While conducting a production blasting, the waves induced by blasting of different holes interfere destructively with each other, which may result in higher PPV than the predicted value with scaled distance regression analysis. This phenomenon of interference/superimposition of waves is not considered while using scaled distance regression analysis. In this paper, an attempt has been made to compare the predicted values of blast-induced ground vibration using multi-hole trial blasting with single-hole blasting in an opencast coal mine under the same geological condition. Further,the modified prediction equation for the multi-hole trial blasting was obtained using single-hole regression analysis. The error between predicted and actual values of multi-hole blast-induced ground vibration was found to be reduced by 8.5%.展开更多
Two loosely coupled single degree of freedom (SDOF) systems were used to model the flexural and direct shear responses of one-way reinforced concrete slabs subjected to explosive loading. Blast test results show that ...Two loosely coupled single degree of freedom (SDOF) systems were used to model the flexural and direct shear responses of one-way reinforced concrete slabs subjected to explosive loading. Blast test results show that the SDOF systems are accurate in predicting the failure mode of the slab under blast loads by incorporating the effects of the strain rate effect caused by rapid load application. Based on different damage criteria, pressure-impulse (P-I) diagrams of the two failure modes were analyzed with the SDOF systems. The effects of span length, concrete strength, and reinforcement ratio of the slab on the P-I diagram were also investigated. Results indicate that a slab tends to fail in direct shear mode when it is of a smaller span length and tends to fail in flexure mode when it is of a larger span length. With the increase of the concrete strength or reinforced ratio, both the flexure and shear capacity increase. Based on numerical results, a simplified method and a semi analytical equation for deriving the P-I diagram are proposed for different failure modes and damage levels.展开更多
基金supported by the earmarked fund for China Agricultural Research System (CARS-01-33)the National Key Research and Development Program of China (2016YFD0300703)
文摘Single spore isolation is a fundamental approach in plant pathology and mycology to isolate and identify plant fungal pathogens from diseased samples.However,routine single spore isolation procedure is time-consuming and has a high risk of contamination by other microorganisms.In this study,we developed a rapid approach for isolating a single spore of the fungal pathogen,Pyricularia oryzae,from rice blast diseased leaves in the paddy field with low potential of contamination.First,rice blast leaves with single lesions were selected in the paddy field,and a single lesion was cut out and pressed and dragged gently across the surface of water agar.Next,a germinated single spore with a barely visible piece of agar was cut out of water agar with a dissecting needle under a stereomicroscope at approximately 120-fold magnification.Last,the germinated single spore with water agar was transferred onto oatmeal tomato agar for growth and preservation.Based on our experience,a skilled technician or student can successfully isolate single spore from over 150 independent diseased samples with nearly no contaminations in a single working day.This approach is also suitable for isolating single spore from other fungal disease samples that produce abundant aerial conidia.
文摘The blast-induced ground vibration prediction using scaled distance regression analysis is one of the most popular methods employed by engineers for many decades. It uses the maximum charge per delay and distance of monitoring as the major factors for predicting the peak particle velocity(PPV). It is established that the PPV is caused by the maximum charge per delay which varies with the distance of monitoring and site geology. While conducting a production blasting, the waves induced by blasting of different holes interfere destructively with each other, which may result in higher PPV than the predicted value with scaled distance regression analysis. This phenomenon of interference/superimposition of waves is not considered while using scaled distance regression analysis. In this paper, an attempt has been made to compare the predicted values of blast-induced ground vibration using multi-hole trial blasting with single-hole blasting in an opencast coal mine under the same geological condition. Further,the modified prediction equation for the multi-hole trial blasting was obtained using single-hole regression analysis. The error between predicted and actual values of multi-hole blast-induced ground vibration was found to be reduced by 8.5%.
基金Project(JC11-02-18) supported by the Scientific Foundation of National University of Defense Technology, ChinaProject(11202236) supported by the National Natural Science Foundation of China
文摘Two loosely coupled single degree of freedom (SDOF) systems were used to model the flexural and direct shear responses of one-way reinforced concrete slabs subjected to explosive loading. Blast test results show that the SDOF systems are accurate in predicting the failure mode of the slab under blast loads by incorporating the effects of the strain rate effect caused by rapid load application. Based on different damage criteria, pressure-impulse (P-I) diagrams of the two failure modes were analyzed with the SDOF systems. The effects of span length, concrete strength, and reinforcement ratio of the slab on the P-I diagram were also investigated. Results indicate that a slab tends to fail in direct shear mode when it is of a smaller span length and tends to fail in flexure mode when it is of a larger span length. With the increase of the concrete strength or reinforced ratio, both the flexure and shear capacity increase. Based on numerical results, a simplified method and a semi analytical equation for deriving the P-I diagram are proposed for different failure modes and damage levels.
