To solve the problem of high labour costs in the strawberry picking process,the approach of a strawberry picking robot to identify and find strawberries is suggested in this study.First,1000 images including mature,im...To solve the problem of high labour costs in the strawberry picking process,the approach of a strawberry picking robot to identify and find strawberries is suggested in this study.First,1000 images including mature,immature,single,multiple,and occluded strawberries were collected,and a two-stage detection Mask R-CNN instance segmentation network and a one-stage detection YOLOv3 target detection network were used to train a strawberry identification model which classified strawberries into two categories:mature and immature.The accuracy ratings for YOLOv3 and Mask R-CNN were 93.4%and 94.5%,respectively.Second,the ZED stereo camera,triangulation,and a neural network were used to locate the strawberry in three dimensions.YOLOv3 identification accuracy was 3.1 mm,compared to Mask R-CNN of 3.9 mm.The strawberry detection and positioning method proposed in this study may effectively be used to supply the picking robot with a precise location of the ripe strawberry.展开更多
A new assay method for natural killer (NK) cell activity was established using quantitative RT-PCR (RT-qPCR) to determine the gene expression of granzyme B (GzmB) and perforin 1 (Prf1). The RT-qPCR method was compared...A new assay method for natural killer (NK) cell activity was established using quantitative RT-PCR (RT-qPCR) to determine the gene expression of granzyme B (GzmB) and perforin 1 (Prf1). The RT-qPCR method was compared to a conventional cytotoxic assay. Upregulated expression of GzmB and Prf1 mRNA and enhanced cytotoxic activity were observed in splenocytes from lipopolysaccharide (LPS)-treated rats. A high correlation, R<sup>2</sup> = 0.71, was observed between the gene expression of GzmB and the cytotoxic activity of splenocytes from these rats, indicating that GzmB RT-qPCR is a reliable alternative method to assess NK cell activity/activation. Remarkably, 12.6- to 59.7-fold upregulation of GzmB mRNA expression was observed in leukocytes, the spleen, and splenocytes from LPS-injected rats. Its upregulation appeared to be dose-dependent on the LPS concentration in the range of 0.01 - 0.1 mg/kg. Whereas, only 1.3- to 1.9-fold increase of cytotoxic activity was detected in splenocytes from the rats treated with LPS in the same range. From these, it is evident that, to assess NK cell activity/activation, the GzmB RT-qPCR method is highly sensitive compared with the conventional cytological assay. Furthermore, this GzmB RT-qPCR method is advantageous, as it does not require freshly prepared splenocytes and cell culture procedures. The convenience of GzmB RT-qPCR enables the use of whole blood, leukocytes, the spleen, and/or their frozen samples to evaluate NK cell activity/activation.展开更多
In order to improve the deposition and uniformity of the pesticide sprayed by the agricultural spraying drone,this study designed a novel spraying system,combining air-assisted spraying system with electrostatic techn...In order to improve the deposition and uniformity of the pesticide sprayed by the agricultural spraying drone,this study designed a novel spraying system,combining air-assisted spraying system with electrostatic technology.First,an air-assisted electrostatic centrifugal spray system was designed for agricultural spraying drones,including a shell,a diversion shell,and an electrostatic ring.Then,experiments were conducted to optimize the setting of the main parameters that affect the charge-to-mass ratio,and outdoor spraying experiments were carried out on the spraying effect of the air-assisted electrostatic centrifugal spray system.The results showed the optimum parameters were that the centrifugal rotation speed was 10000 r/min,the spray pressure was 0.3 MPa,the fan rotation speed was 14000 r/min,and the electrostatic generator voltage was 9 kV;The optimum charge-to-mass ratio of the spray system was 2.59 mC/kg.The average deposition density of droplets on the collecting platform was 366.1 particles/cm^(2) on the upper layer,345.1 particles/cm^(2) on the middle layer,and 322.5 particles/cm^(2) on the lower layer.Compared to the results of uncharged droplets on the upper,middle,and lower layers,the average deposition density was increased by 34.9%,30.4%,and 30.2%,respectively,and the uniformity of the distribution of the droplets at different collection points was better.展开更多
The lifetime prediction of ceramics is discussed on the basis of therelationship between stress intensity factor K_1 and crack velocity nu. The effects of waterenvironment, the cyclic loading and microstructure of mat...The lifetime prediction of ceramics is discussed on the basis of therelationship between stress intensity factor K_1 and crack velocity nu. The effects of waterenvironment, the cyclic loading and microstructure of material on K_1-nu characteristics are studiedby carrying out the crack growth tests by the double torsion (DT) method under the static andcyclic loading in both environments of air and water for alumina and zirconia. K_1-nucharacteristics determined by the double torsion method are used to predict time-to-failure underthe cyclic loading of alumina and zirconia ceramics. The predictions agree qualitatively with theexperimental results.展开更多
The authors consider the exact controllability of the vibrations of a thin shallow shell, of thickness 2ε with controls imposed on the lateral surface and at the top and bottom of the shell. Apart from proving the ex...The authors consider the exact controllability of the vibrations of a thin shallow shell, of thickness 2ε with controls imposed on the lateral surface and at the top and bottom of the shell. Apart from proving the existence of exact controls, it is shown that the solutions of the three dimensional exact controllability problems converge, as the thickhess of the shell goes to zero, to the solution of an exact controllability problem in two dimensions.展开更多
Inulin is a soluble and indigestible fiber derived from natural plants such as Jerusalem artichoke (Helianthus tuberosus), “Kikuimo”. In the current study, a nutrigenomics approach was utilized to evaluate the in vi...Inulin is a soluble and indigestible fiber derived from natural plants such as Jerusalem artichoke (Helianthus tuberosus), “Kikuimo”. In the current study, a nutrigenomics approach was utilized to evaluate the in vivo function of “Kikuimo Extract” (KE) in ovariectomized cynomolgus macaque, a post-menopausal non-human primate model. KE was administered orally before feeding, for 3 months for the following examinations: 1) the effect of KE on intestinal microbes was examined by quantitative analyses of the intestinal bacteria using real-time PCR with DNA extracted from monkey feces;2) the effect of KE on gene expression was investigated by real-time RT-PCR using RNA extracted from both the liver and adipose tissue of the monkeys. KE administration modulated menopause-mediated altered microbes to increase Lactobacilli, Veillonella, and Bacteroides in all monkeys. KE administration regulated the altered expression of functional genes, SCAP, LDLR, and LXRA (lipid metabolism);GLUT-4 (glucose transport);CYP1A1 and CYP1A2 (drug metabolism);and CYP-17-2 and CYP-19-2 (E2 synthesis) in the menopausal monkeys. In menopausal monkeys, KE showed potent prebiotic effect on beneficial microflora and regulating effect on altered expression of functional genes associated with metabolism and E2 production. Thus, KE appears to be a practical functional food that alleviates the altered conditions of intestinal microbes and gene expression in the liver and adipose tissue in a menopausal state.展开更多
The groove shape of the weld faying part was investigated to obtain an ideal pipe frictiowelded joint that had a fracture in the base metal and no inner flash of it.The steel pipe had inner and outer diameters of 8.0 ...The groove shape of the weld faying part was investigated to obtain an ideal pipe frictiowelded joint that had a fracture in the base metal and no inner flash of it.The steel pipe had inner and outer diameters of 8.0 mm and 13.5 mm,respectively,and the weld faying surface was of a basic flat shape(butt)type.Moreover,stepped and tapered groove shapes were prepared.Pipe groove shapes were welded with a friction speed of 27.5 s_1 and a friction load of 2.79 kN.Joining phenomena during the welding process were observed,and the tensile strength of joints was evaluated.The joints,that fabricated with flat or step groove shapes,made with a friction time at which the friction torque reached the initial peak did not have the tensile strength of the base metal nor a fracture in the base metal.However,the joints fabricated with a friction time that reached past the initial peak had a large flash,and they contained a fracture in the base metal.In contrast,when joints were made with a gently tapered groove shape with a friction time reaching the time of the initial peak,they achieved a fracture in the base metal,despite having an extremely small inner flash.Therefore,the shape at the weld faying part was capable of reducing the flash exhausted from the weld interface.展开更多
In this study,the effect of core bar inserted into weld faying part to obtain an ideal pipe joint with non-generating inner flash via friction welding is described.A steel pipe with inner and outer diameters correspon...In this study,the effect of core bar inserted into weld faying part to obtain an ideal pipe joint with non-generating inner flash via friction welding is described.A steel pipe with inner and outer diameters corresponding to 8.0 mm and 13.5 mm was used,and the weld faying surface was machined to a groove shape of a flat(butt)type.The core bar of various materials was inserted in the weld faying part of the pipes,and those pipes were welded with a friction speed of 27.5 s−1 and friction pressure of 30 MPa.The core bars did not decrease inner flash when joints were fabricated with a core bar of some metallic materials with melting points below that of steel;thus,they were melted during the welding process.The joint with an alumina core bar did not decrease inner flash and was crushed by generating an inner flash.However,a commercially pure tungsten(CP-W)core bar was successfully achieved for decreasing the inner flash.Additionally,all joints with a CP-W core bar did not exhibit the tensile strength of the base metal and a fracture in the base metal,when they were fabricated during the same time,the friction torque reached the initial peak.The joint exhibited a fracture in the base metal when it was fabricated with a CP-W core bar and a taper groove shape that was proposed in the previous study.Furthermore,the core bars were easily removed from the joints;thus the joint with almost no inner flash was successfully obtained.To reduce the inner flash of pipe joints,they should be fabricated with a CP-W core bar inserted into the weld faying part with a taper groove shape.展开更多
文摘To solve the problem of high labour costs in the strawberry picking process,the approach of a strawberry picking robot to identify and find strawberries is suggested in this study.First,1000 images including mature,immature,single,multiple,and occluded strawberries were collected,and a two-stage detection Mask R-CNN instance segmentation network and a one-stage detection YOLOv3 target detection network were used to train a strawberry identification model which classified strawberries into two categories:mature and immature.The accuracy ratings for YOLOv3 and Mask R-CNN were 93.4%and 94.5%,respectively.Second,the ZED stereo camera,triangulation,and a neural network were used to locate the strawberry in three dimensions.YOLOv3 identification accuracy was 3.1 mm,compared to Mask R-CNN of 3.9 mm.The strawberry detection and positioning method proposed in this study may effectively be used to supply the picking robot with a precise location of the ripe strawberry.
文摘A new assay method for natural killer (NK) cell activity was established using quantitative RT-PCR (RT-qPCR) to determine the gene expression of granzyme B (GzmB) and perforin 1 (Prf1). The RT-qPCR method was compared to a conventional cytotoxic assay. Upregulated expression of GzmB and Prf1 mRNA and enhanced cytotoxic activity were observed in splenocytes from lipopolysaccharide (LPS)-treated rats. A high correlation, R<sup>2</sup> = 0.71, was observed between the gene expression of GzmB and the cytotoxic activity of splenocytes from these rats, indicating that GzmB RT-qPCR is a reliable alternative method to assess NK cell activity/activation. Remarkably, 12.6- to 59.7-fold upregulation of GzmB mRNA expression was observed in leukocytes, the spleen, and splenocytes from LPS-injected rats. Its upregulation appeared to be dose-dependent on the LPS concentration in the range of 0.01 - 0.1 mg/kg. Whereas, only 1.3- to 1.9-fold increase of cytotoxic activity was detected in splenocytes from the rats treated with LPS in the same range. From these, it is evident that, to assess NK cell activity/activation, the GzmB RT-qPCR method is highly sensitive compared with the conventional cytological assay. Furthermore, this GzmB RT-qPCR method is advantageous, as it does not require freshly prepared splenocytes and cell culture procedures. The convenience of GzmB RT-qPCR enables the use of whole blood, leukocytes, the spleen, and/or their frozen samples to evaluate NK cell activity/activation.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFD0200800)the Key Research and Development Program of Hunan Province(Grant No.2018GK2013)+1 种基金Hunan Modern Agricultural Industry Technology Program(Grant No.201926)Innovation and Entrepreneurship Training Program of Hunan Agricultural University(Grant No.2019062x).
文摘In order to improve the deposition and uniformity of the pesticide sprayed by the agricultural spraying drone,this study designed a novel spraying system,combining air-assisted spraying system with electrostatic technology.First,an air-assisted electrostatic centrifugal spray system was designed for agricultural spraying drones,including a shell,a diversion shell,and an electrostatic ring.Then,experiments were conducted to optimize the setting of the main parameters that affect the charge-to-mass ratio,and outdoor spraying experiments were carried out on the spraying effect of the air-assisted electrostatic centrifugal spray system.The results showed the optimum parameters were that the centrifugal rotation speed was 10000 r/min,the spray pressure was 0.3 MPa,the fan rotation speed was 14000 r/min,and the electrostatic generator voltage was 9 kV;The optimum charge-to-mass ratio of the spray system was 2.59 mC/kg.The average deposition density of droplets on the collecting platform was 366.1 particles/cm^(2) on the upper layer,345.1 particles/cm^(2) on the middle layer,and 322.5 particles/cm^(2) on the lower layer.Compared to the results of uncharged droplets on the upper,middle,and lower layers,the average deposition density was increased by 34.9%,30.4%,and 30.2%,respectively,and the uniformity of the distribution of the droplets at different collection points was better.
文摘The lifetime prediction of ceramics is discussed on the basis of therelationship between stress intensity factor K_1 and crack velocity nu. The effects of waterenvironment, the cyclic loading and microstructure of material on K_1-nu characteristics are studiedby carrying out the crack growth tests by the double torsion (DT) method under the static andcyclic loading in both environments of air and water for alumina and zirconia. K_1-nucharacteristics determined by the double torsion method are used to predict time-to-failure underthe cyclic loading of alumina and zirconia ceramics. The predictions agree qualitatively with theexperimental results.
文摘The authors consider the exact controllability of the vibrations of a thin shallow shell, of thickness 2ε with controls imposed on the lateral surface and at the top and bottom of the shell. Apart from proving the existence of exact controls, it is shown that the solutions of the three dimensional exact controllability problems converge, as the thickhess of the shell goes to zero, to the solution of an exact controllability problem in two dimensions.
文摘Inulin is a soluble and indigestible fiber derived from natural plants such as Jerusalem artichoke (Helianthus tuberosus), “Kikuimo”. In the current study, a nutrigenomics approach was utilized to evaluate the in vivo function of “Kikuimo Extract” (KE) in ovariectomized cynomolgus macaque, a post-menopausal non-human primate model. KE was administered orally before feeding, for 3 months for the following examinations: 1) the effect of KE on intestinal microbes was examined by quantitative analyses of the intestinal bacteria using real-time PCR with DNA extracted from monkey feces;2) the effect of KE on gene expression was investigated by real-time RT-PCR using RNA extracted from both the liver and adipose tissue of the monkeys. KE administration modulated menopause-mediated altered microbes to increase Lactobacilli, Veillonella, and Bacteroides in all monkeys. KE administration regulated the altered expression of functional genes, SCAP, LDLR, and LXRA (lipid metabolism);GLUT-4 (glucose transport);CYP1A1 and CYP1A2 (drug metabolism);and CYP-17-2 and CYP-19-2 (E2 synthesis) in the menopausal monkeys. In menopausal monkeys, KE showed potent prebiotic effect on beneficial microflora and regulating effect on altered expression of functional genes associated with metabolism and E2 production. Thus, KE appears to be a practical functional food that alleviates the altered conditions of intestinal microbes and gene expression in the liver and adipose tissue in a menopausal state.
文摘The groove shape of the weld faying part was investigated to obtain an ideal pipe frictiowelded joint that had a fracture in the base metal and no inner flash of it.The steel pipe had inner and outer diameters of 8.0 mm and 13.5 mm,respectively,and the weld faying surface was of a basic flat shape(butt)type.Moreover,stepped and tapered groove shapes were prepared.Pipe groove shapes were welded with a friction speed of 27.5 s_1 and a friction load of 2.79 kN.Joining phenomena during the welding process were observed,and the tensile strength of joints was evaluated.The joints,that fabricated with flat or step groove shapes,made with a friction time at which the friction torque reached the initial peak did not have the tensile strength of the base metal nor a fracture in the base metal.However,the joints fabricated with a friction time that reached past the initial peak had a large flash,and they contained a fracture in the base metal.In contrast,when joints were made with a gently tapered groove shape with a friction time reaching the time of the initial peak,they achieved a fracture in the base metal,despite having an extremely small inner flash.Therefore,the shape at the weld faying part was capable of reducing the flash exhausted from the weld interface.
文摘In this study,the effect of core bar inserted into weld faying part to obtain an ideal pipe joint with non-generating inner flash via friction welding is described.A steel pipe with inner and outer diameters corresponding to 8.0 mm and 13.5 mm was used,and the weld faying surface was machined to a groove shape of a flat(butt)type.The core bar of various materials was inserted in the weld faying part of the pipes,and those pipes were welded with a friction speed of 27.5 s−1 and friction pressure of 30 MPa.The core bars did not decrease inner flash when joints were fabricated with a core bar of some metallic materials with melting points below that of steel;thus,they were melted during the welding process.The joint with an alumina core bar did not decrease inner flash and was crushed by generating an inner flash.However,a commercially pure tungsten(CP-W)core bar was successfully achieved for decreasing the inner flash.Additionally,all joints with a CP-W core bar did not exhibit the tensile strength of the base metal and a fracture in the base metal,when they were fabricated during the same time,the friction torque reached the initial peak.The joint exhibited a fracture in the base metal when it was fabricated with a CP-W core bar and a taper groove shape that was proposed in the previous study.Furthermore,the core bars were easily removed from the joints;thus the joint with almost no inner flash was successfully obtained.To reduce the inner flash of pipe joints,they should be fabricated with a CP-W core bar inserted into the weld faying part with a taper groove shape.
