The congenital yield reduction caused by miss-seeding in spoon-type seed-metering device of small and medium-sized potato planter is huge.Based on the physical mechanism of different measured capacitance values betwee...The congenital yield reduction caused by miss-seeding in spoon-type seed-metering device of small and medium-sized potato planter is huge.Based on the physical mechanism of different measured capacitance values between two fixed capacitor plates with different media,a miss-seeding detection scheme based on a spatial capacitance sensor is proposed first.A simple and efficient spatial capacitance sensor that can obtain as large capacitance measurement value as possible is designed,and a dual CPU coordinated seed-monitoring and compensation control system architecture is adopted.AD7745 is selected for the capacitance measure of the spatial capacitance sensor,and the code of grating encoder is also recorded at the same time.Thereby,when each potato spoon passing through the space surrounded by the capacitor plates,the maximum net capacitance fluctuation and its corresponding position can be acquired.A suitable threshold can distinguish between normal-seeding and miss-seeding effectively.Moreover,it should be emphasized that,this monitoring system only requires one monitoring point.Then,based on obtained information,an improved miss-seeding catching-up compensation plan is put forward.By utilizing the powerful memory capability of the CPU,this system does not need to complete compensation immediately after the miss-seeding identification.Instead,the miss-seeding information and the location of the accident can be just marked in advance,and only when the opportunity arrives,can the miss-seeding catching-up compensation be truly executed.In this way,the position of the seed-monitoring points can be free from restriction,and the control strategy can therefore be significantly simplified.The soil tank test data showed that,the identification accuracy of the miss-seeding detection system was not less than 94%.When the seed-metering chain speeds are 0.2,0.3,and 0.4 m/s,the average success rates of the miss-seeding compensation system are 94.32%,83.65%,and 75.00%,respectively.The final miss-seeding rate can be below 3%,and the average deviation compensation rate was not higher than 30%,the miss-seeding was suppressed significantly.This system is a beneficial try in the non-photoelectric detection field and low complexity miss-seeding compensation for potato seeding.展开更多
Helicobacter pylori(H.pylori)plays an important role in gastric carcinogenesis,as the majority of gastric cancers develop from H.pylori-infected gastric mucosa.The rate of early gastric cancer diagnosis has increased ...Helicobacter pylori(H.pylori)plays an important role in gastric carcinogenesis,as the majority of gastric cancers develop from H.pylori-infected gastric mucosa.The rate of early gastric cancer diagnosis has increased in Japan and Korea,where H.pylori infection and gastric cancer are highly prevalent.Early intestinal-type gastric cancer without concomitant lymph node metastasis is usually treated by endoscopic resection.Secondary metachronous gastric cancers often develop because atrophic mucosa left untreated after endoscopic treatment confers a high risk of gastric cancer.The efficacy of H.pylori eradication for the prevention of metachronous gastric cancer remains controversial.However,in patients who undergo endoscopic resection of early gastric cancer,H.pylori eradication is recommended to suppress or delay metachronous gastric cancer.Careful and regularly scheduled endoscopy should be performed to detect minute metachronous gastric cancer after endoscopic resection.展开更多
Land is rare natural resource.Production and construction of all sectors in a region must be based on land.Thus,overall research and analysis on current situation of land use can reveal scope,depth and reasonableness ...Land is rare natural resource.Production and construction of all sectors in a region must be based on land.Thus,overall research and analysis on current situation of land use can reveal scope,depth and reasonableness of land use,is helpful for analyzing internal mechanism land use change,and can reflect production scale,level and characteristics,and also can provide basis for optimization and adjustment of land use structure.Based on RS and GIS technologies,with the aid of TM image data of the Three-gorges Reservoir Region in 2010,the data of current situation of land use in Three-gorges Reservoir Region was obtained,and current land use situation was analyzed using geographimetrics and landscape ecology methods.Results show that since natural,social and economic conditions are different,land type diversity,combination type and location index of counties in the Three-gorges Reservoir Region are varied.In the land use diversity index,Xingshan County has the most single land use type(mainly forest land); in land use degree,Yuzhong District has the highest land use degree; in the integrated index of land use,Changshou District has the lowest integrated index of land use.This study is expected to provide reference and basis for formulating policies of protecting ecological environment of the Three-gorges Reservoir Region.展开更多
基金support of the Industrial support plan of the Gansu Provincial Department of Education(Grant No.2023CYZC-42)the National Natural Science Foundation of China(Grant No.52165028)the Key Scientific and the Technological Program of Gansu Province(Grant No.22ZD6NA046).
文摘The congenital yield reduction caused by miss-seeding in spoon-type seed-metering device of small and medium-sized potato planter is huge.Based on the physical mechanism of different measured capacitance values between two fixed capacitor plates with different media,a miss-seeding detection scheme based on a spatial capacitance sensor is proposed first.A simple and efficient spatial capacitance sensor that can obtain as large capacitance measurement value as possible is designed,and a dual CPU coordinated seed-monitoring and compensation control system architecture is adopted.AD7745 is selected for the capacitance measure of the spatial capacitance sensor,and the code of grating encoder is also recorded at the same time.Thereby,when each potato spoon passing through the space surrounded by the capacitor plates,the maximum net capacitance fluctuation and its corresponding position can be acquired.A suitable threshold can distinguish between normal-seeding and miss-seeding effectively.Moreover,it should be emphasized that,this monitoring system only requires one monitoring point.Then,based on obtained information,an improved miss-seeding catching-up compensation plan is put forward.By utilizing the powerful memory capability of the CPU,this system does not need to complete compensation immediately after the miss-seeding identification.Instead,the miss-seeding information and the location of the accident can be just marked in advance,and only when the opportunity arrives,can the miss-seeding catching-up compensation be truly executed.In this way,the position of the seed-monitoring points can be free from restriction,and the control strategy can therefore be significantly simplified.The soil tank test data showed that,the identification accuracy of the miss-seeding detection system was not less than 94%.When the seed-metering chain speeds are 0.2,0.3,and 0.4 m/s,the average success rates of the miss-seeding compensation system are 94.32%,83.65%,and 75.00%,respectively.The final miss-seeding rate can be below 3%,and the average deviation compensation rate was not higher than 30%,the miss-seeding was suppressed significantly.This system is a beneficial try in the non-photoelectric detection field and low complexity miss-seeding compensation for potato seeding.
文摘Helicobacter pylori(H.pylori)plays an important role in gastric carcinogenesis,as the majority of gastric cancers develop from H.pylori-infected gastric mucosa.The rate of early gastric cancer diagnosis has increased in Japan and Korea,where H.pylori infection and gastric cancer are highly prevalent.Early intestinal-type gastric cancer without concomitant lymph node metastasis is usually treated by endoscopic resection.Secondary metachronous gastric cancers often develop because atrophic mucosa left untreated after endoscopic treatment confers a high risk of gastric cancer.The efficacy of H.pylori eradication for the prevention of metachronous gastric cancer remains controversial.However,in patients who undergo endoscopic resection of early gastric cancer,H.pylori eradication is recommended to suppress or delay metachronous gastric cancer.Careful and regularly scheduled endoscopy should be performed to detect minute metachronous gastric cancer after endoscopic resection.
基金Supported by Project of National Natural Science Foundation(41101503)Key Project of National Social Science Foundation(11&ZD161)
文摘Land is rare natural resource.Production and construction of all sectors in a region must be based on land.Thus,overall research and analysis on current situation of land use can reveal scope,depth and reasonableness of land use,is helpful for analyzing internal mechanism land use change,and can reflect production scale,level and characteristics,and also can provide basis for optimization and adjustment of land use structure.Based on RS and GIS technologies,with the aid of TM image data of the Three-gorges Reservoir Region in 2010,the data of current situation of land use in Three-gorges Reservoir Region was obtained,and current land use situation was analyzed using geographimetrics and landscape ecology methods.Results show that since natural,social and economic conditions are different,land type diversity,combination type and location index of counties in the Three-gorges Reservoir Region are varied.In the land use diversity index,Xingshan County has the most single land use type(mainly forest land); in land use degree,Yuzhong District has the highest land use degree; in the integrated index of land use,Changshou District has the lowest integrated index of land use.This study is expected to provide reference and basis for formulating policies of protecting ecological environment of the Three-gorges Reservoir Region.
