The cup-chain metering device is commonly used in potato planters despite its problems of missing-seeding,double-seeding and ground wheel sliding.A mechanical-electrical design was developed for planters to resolve th...The cup-chain metering device is commonly used in potato planters despite its problems of missing-seeding,double-seeding and ground wheel sliding.A mechanical-electrical design was developed for planters to resolve these problems.A regression experiment was conducted with three factors(chain speed,chain tightening distance and cup tilting)and two indicators(missing-seeding rate and double-seeding rate).Based on the results of regression experiment,a numerical regression model was built and a multi-objective optimization method was used to get an optimal solution.Subsequently,the optimized device was tested in the field.The device design presents a tilting seed cup with a guard plate and an electric control system.The laboratory test showed that the missing-seeding rate increased with the chain speed.It initially decreases and then increases with the chain tightening distance and cup tilting angle.The double-seeding rate declines with chain speed.It increases initially and declines afterward with the chain tightening distance.The optimization resulted in a missing-seeding rate of 4.39%and a double-seeding rate of 8.78%under the parameters of 0.32 m/s seeding speed,0.94×10-3 m tightening distance,and 12.5°cup tilting angle.The field test demonstrated that electric control instead of ground wheel-driven chain enables fast seeding and precise intra-row seeding distance.展开更多
Ciprofloxacin is a second-generation of fluoroquinolone,broad-spectrum antibiotic with bactericidal activity against Gram-positive and Gram-negative organisms.It is one of the most widely used antibiotics,because of i...Ciprofloxacin is a second-generation of fluoroquinolone,broad-spectrum antibiotic with bactericidal activity against Gram-positive and Gram-negative organisms.It is one of the most widely used antibiotics,because of its efficacy,safety,and relatively low cost.Ascorbic acid(vitamin C)is water-soluble monosaccharide antioxidant;it is essentially required by the body for its various biochemical and physiological processes.S.aureus is Gram-positive cocci;widely distributed in the environment,it is a member of the normal flora of the body.S.aureus is not always pathogenic;it is a common cause of skin infections including abscesses,respiratory infections such as sinusitis,and food poisoning.E.coli is Gram-negative bacteria,found in the environment,foods,and intestines.Most E.coli strains are harmless;it is part of the normal microbiota of the gut.However,some serotypes of E.coli cause serious food poisoning in their hosts;it can cause diarrhea,while others cause urinary tract infections,respiratory illness and pneumonia,and other illnesses.Method:Cup cut diffusion method was applied.Experiment I:is carried out to choose the concentration of vitamin C to be used in experiment II.The negative control is normal saline,added in cup in each plate,vitamin C(100 mg/mL,200 mg/mL,400 mg/mL)was added,the volume in each cup was 100μL.Experiment II:Eight groups of treatments were applied.The first is the negative control(1%normal saline),the second group is the positive control of vitamin C(200 mg/mL).The third,fourth and fifth groups are ciprofloxacin with different concentrations(10 mg/mL,20 mg/mL,40 mg/mL);the sixth,seventh and eighth are the combination of vitamin C with each concentration of ciprofloxacin(10 mg/mL,20 mg/mL,40 mg/mL).Each group includes six petri dishes.Bacterial plates were incubated at 37 oC for 24 h and 48 h.Zone of inhibition is measured in mm.Results and conclusion:Ciprofloxacin produces dose dependent increase in zone of inhibition of S.aureus and E.coli growth,after 24 and 48 hours incubation.While vit展开更多
基金the State's Key Project of Research and Development Plan(2016YFD0700103)National Natural Science Foundation of China(31301241).
文摘The cup-chain metering device is commonly used in potato planters despite its problems of missing-seeding,double-seeding and ground wheel sliding.A mechanical-electrical design was developed for planters to resolve these problems.A regression experiment was conducted with three factors(chain speed,chain tightening distance and cup tilting)and two indicators(missing-seeding rate and double-seeding rate).Based on the results of regression experiment,a numerical regression model was built and a multi-objective optimization method was used to get an optimal solution.Subsequently,the optimized device was tested in the field.The device design presents a tilting seed cup with a guard plate and an electric control system.The laboratory test showed that the missing-seeding rate increased with the chain speed.It initially decreases and then increases with the chain tightening distance and cup tilting angle.The double-seeding rate declines with chain speed.It increases initially and declines afterward with the chain tightening distance.The optimization resulted in a missing-seeding rate of 4.39%and a double-seeding rate of 8.78%under the parameters of 0.32 m/s seeding speed,0.94×10-3 m tightening distance,and 12.5°cup tilting angle.The field test demonstrated that electric control instead of ground wheel-driven chain enables fast seeding and precise intra-row seeding distance.
文摘Ciprofloxacin is a second-generation of fluoroquinolone,broad-spectrum antibiotic with bactericidal activity against Gram-positive and Gram-negative organisms.It is one of the most widely used antibiotics,because of its efficacy,safety,and relatively low cost.Ascorbic acid(vitamin C)is water-soluble monosaccharide antioxidant;it is essentially required by the body for its various biochemical and physiological processes.S.aureus is Gram-positive cocci;widely distributed in the environment,it is a member of the normal flora of the body.S.aureus is not always pathogenic;it is a common cause of skin infections including abscesses,respiratory infections such as sinusitis,and food poisoning.E.coli is Gram-negative bacteria,found in the environment,foods,and intestines.Most E.coli strains are harmless;it is part of the normal microbiota of the gut.However,some serotypes of E.coli cause serious food poisoning in their hosts;it can cause diarrhea,while others cause urinary tract infections,respiratory illness and pneumonia,and other illnesses.Method:Cup cut diffusion method was applied.Experiment I:is carried out to choose the concentration of vitamin C to be used in experiment II.The negative control is normal saline,added in cup in each plate,vitamin C(100 mg/mL,200 mg/mL,400 mg/mL)was added,the volume in each cup was 100μL.Experiment II:Eight groups of treatments were applied.The first is the negative control(1%normal saline),the second group is the positive control of vitamin C(200 mg/mL).The third,fourth and fifth groups are ciprofloxacin with different concentrations(10 mg/mL,20 mg/mL,40 mg/mL);the sixth,seventh and eighth are the combination of vitamin C with each concentration of ciprofloxacin(10 mg/mL,20 mg/mL,40 mg/mL).Each group includes six petri dishes.Bacterial plates were incubated at 37 oC for 24 h and 48 h.Zone of inhibition is measured in mm.Results and conclusion:Ciprofloxacin produces dose dependent increase in zone of inhibition of S.aureus and E.coli growth,after 24 and 48 hours incubation.While vit
