Abstract: The present disclosure provides a sampling device of acquiring a graphite sample from a reactor graphite block, and the sampling device includes: a support placed on the reactor graphite block; a lifter configured to be insertable into the reactor graphite block in a first direction; a sampling actuator arranged at an end of the lifter and configured to acquire a graphite sample from the reactor graphite block. The sampling actuator is configured to insert into the reactor graphite block in a second direction, and the first direction is substantially perpendicular to the second direction.

Abstract: A method including: manufacturing a standard transmission object; simulating a transmission measurement process using simulation calculation method, to establish a database with respect to a transmission thickness, an equivalent water density, an original reconstruction density of the standard transmission object, a space angle cosine of the transmission source and an energy of a ? ray, fitting a corresponding relationship of the space angle cosine of the transmission source with respect to parameters of the standard transmission object and the energy of the ? ray based on the database; selecting a corresponding standard transmission object for transmission measurement for a transmission source to be characterized, to obtain an original reconstruction density of the standard transmission object; reading the space angle cosine of the transmission source to be characterized from the database according to fitted corresponding relationship of known parameters of the standard transmission object and the energy of

Abstract: A system for controlling centralized brake of vehicles, comprising: a pressure collection device for collecting the pressure of a main blast pipe and a train pipe control device. The pressure signal output end of the pressure collection device is connected to the pressure signal input end of the train pipe control device; the brake signal input end of the train pipe control device is connected to the brake signal output end of a brake controller; the train pipe control device is pneumatically connected to the main blast pipe and a train pipe separately by means of an air channel. By means of the solution, the installation space of a trailer is reduced, and the costs are lowered.

Abstract: The disclosure discloses a simplified space vector modulation method for multi-lever converters, and relates to the field of space vector modulation methods for multilevel converters, which solves problems that a redundant on-off state is greatly increased along with increase of a number of levels in a traditional SVM technology, and SVM is difficult to realize due to calculation of the redundant on-off state and selection of a proper on-off state. The method includes the following steps of: step 1: establishing a vector expression; step 2: establishing a reference vector trajectory model; step 3: respectively representing reference signals and level signals by coordinate components of a reference vector and a basic vector and corresponding component sums; step 4: constructing a star-connected multilevel converter; step 5: sampling a phase voltage reference vector trajectory model of the star-connected multilevel converter, and synthesizing the reference vector.

Abstract: The disclosure discloses a simplified space vector modulation method for multi-lever converters, and relates to the field of space vector modulation methods for multilevel converters, which solves problems that a redundant on-off state is greatly increased along with increase of a number of levels in a traditional SVM technology, and SVM is difficult to realize due to calculation of the redundant on-off state and selection of a proper on-off state. The method comprises the following steps of: step 1: establishing a vector expression; step 2: establishing a reference vector trajectory model; step 3: respectively representing reference signals and level signals by coordinate components of a reference vector and a basic vector and corresponding component sums; step 4: constructing a star-connected multilevel converter; step 5: sampling a phase voltage reference vector trajectory model of the star-connected multilevel converter, and synthesizing the reference vector.

Abstract: A system for controlling centralized brake of vehicles, comprising: a pressure collection device for collecting the pressure of a main blast pipe and a train pipe control device. The pressure signal output end of the pressure collection device is connected to the pressure signal input end of the train pipe control device; the brake signal input end of the train pipe control device is connected to the brake signal output end of a brake controller; the train pipe control device is pneumatically connected to the main blast pipe and a train pipe separately by means of an air channel. By means of the solution, the installation space of a trailer is reduced, and the costs are lowered.

Abstract: A process of preparing in high yield racemic ansa-metallocene complexes by reacting a chelated bisamide group 4 metal complex with an ansa-bis-cyclopentodrenyl dianion reagent. The meso isomers are not detectable in the reaction product.

Abstract: The process of preparing ansa-metallocene complexes in high yield by reacting a metal leaving group complex with an aluminum ansa-bis-cyclopentadienyl compound.