An end-effector for a flexible drilling robot is designed, and a novel four-point algorithm of normal attitude regulation for this end-effector is presented. Four non-coplanar points can define a unique sphere tangent...An end-effector for a flexible drilling robot is designed, and a novel four-point algorithm of normal attitude regulation for this end-effector is presented. Four non-coplanar points can define a unique sphere tangent to them in spatial geometry, and the center point of the sphere and the radius can be calculated. The shape of a workpiece surface in the machining area is approximately regarded as such a sphere. A vector from the machining point to the center point is thus approximately regarded as a normal vector to the workpiece surface. By this principle, the algorithm first measures four coordinates on the curve in the drilling region using four sensors and calculates the normal vector at the drilling point, then calculates the error between the normal vector and the axis of the spindle. According to this error, the algorithm further figures out the angles of two revolving axes on the end- effector and the displacements of three linear axes on the robot main body, thus it implements the function of adjusting the spindle to be perpendicular to the curve at the drilling point. Simulation results of two kinds of curved surfaces show that accuracy and efficiency can be realized using the proposed algorithm.展开更多
It is observed by in situ stain that LDH (1 5) ...nNAD + can probably enter the nucleopore and can be bound bound specifically with the genes that encode them. During the in vitro expression, the dilution of heart nuc...It is observed by in situ stain that LDH (1 5) ...nNAD + can probably enter the nucleopore and can be bound bound specifically with the genes that encode them. During the in vitro expression, the dilution of heart nuclear DNA fragments could enhance the expression activity of LDH/DNA and the amount of expressed LDH (1 5) is in proportion to the amount of dissociable LDH (1 5) on the LDH/DNA. With the integration of 14C Leu to the proteins, it is also observed that the addition of LDH (1 5) ...nNAD + can suppress the in vitro expression activity of LDH/DNA. AFM observation shows that the regulation sequence at the both ends of active genes may be bound with such active factors as proteins encoded by the genes which probably is the main molecular switch of gene expression and regulation we have been always searching for. Our work shows the prospective application of the combination of AFM and isotope labeling in the research of biological reaction.展开更多
The small ubiquitin-related modifier （SUMO） modification plays an important role in the regulation of abscisic acid （ABA） signaling, but the function of the SUMO protease, in ABA signaling, remains largely unknown...The small ubiquitin-related modifier （SUMO） modification plays an important role in the regulation of abscisic acid （ABA） signaling, but the function of the SUMO protease, in ABA signaling, remains largely unknown. Here, we show that the SUMO protease, ASPI positively regulates ABA signaling. Mutations in ASPI resulted in an ABA-insensitive phenotype, during early seedling develop- ment. Wild-type ASP1 successfully rescued, whereas an ASPI mutant （C577S）, defective in SUMO protease activity, failed to rescue, the ABA-insensitive phenotype of asp1-1. Expression of ABI5 and MYB3o target genes was attenuated in asp^-I and our genetic analyses revealed that ASP1 may function upstream of ABI5 and MYB3o.展开更多
基金National Science and Technology Major Project(No.2009ZX04014-023)
文摘An end-effector for a flexible drilling robot is designed, and a novel four-point algorithm of normal attitude regulation for this end-effector is presented. Four non-coplanar points can define a unique sphere tangent to them in spatial geometry, and the center point of the sphere and the radius can be calculated. The shape of a workpiece surface in the machining area is approximately regarded as such a sphere. A vector from the machining point to the center point is thus approximately regarded as a normal vector to the workpiece surface. By this principle, the algorithm first measures four coordinates on the curve in the drilling region using four sensors and calculates the normal vector at the drilling point, then calculates the error between the normal vector and the axis of the spindle. According to this error, the algorithm further figures out the angles of two revolving axes on the end- effector and the displacements of three linear axes on the robot main body, thus it implements the function of adjusting the spindle to be perpendicular to the curve at the drilling point. Simulation results of two kinds of curved surfaces show that accuracy and efficiency can be realized using the proposed algorithm.
文摘It is observed by in situ stain that LDH (1 5) ...nNAD + can probably enter the nucleopore and can be bound bound specifically with the genes that encode them. During the in vitro expression, the dilution of heart nuclear DNA fragments could enhance the expression activity of LDH/DNA and the amount of expressed LDH (1 5) is in proportion to the amount of dissociable LDH (1 5) on the LDH/DNA. With the integration of 14C Leu to the proteins, it is also observed that the addition of LDH (1 5) ...nNAD + can suppress the in vitro expression activity of LDH/DNA. AFM observation shows that the regulation sequence at the both ends of active genes may be bound with such active factors as proteins encoded by the genes which probably is the main molecular switch of gene expression and regulation we have been always searching for. Our work shows the prospective application of the combination of AFM and isotope labeling in the research of biological reaction.
基金supported by grants from the National Natural Science Foundation of China(31670186)the Chinese Academy of Sciences(XDA08010105)
文摘The small ubiquitin-related modifier （SUMO） modification plays an important role in the regulation of abscisic acid （ABA） signaling, but the function of the SUMO protease, in ABA signaling, remains largely unknown. Here, we show that the SUMO protease, ASPI positively regulates ABA signaling. Mutations in ASPI resulted in an ABA-insensitive phenotype, during early seedling develop- ment. Wild-type ASP1 successfully rescued, whereas an ASPI mutant （C577S）, defective in SUMO protease activity, failed to rescue, the ABA-insensitive phenotype of asp1-1. Expression of ABI5 and MYB3o target genes was attenuated in asp^-I and our genetic analyses revealed that ASP1 may function upstream of ABI5 and MYB3o.
