Abstract: The present disclosure may provide a system. The system may include a magnetic resonance imaging (MRI) device configured to perform an imaging of a subject. The MRI device may includes a cryostat. The cryostat may include a first cooling chamber and a second cooling chamber that are in fluid communication through a connection conduit. The connection conduit may be located on a side of a central axis of the first cooling chamber or a central axis of the second cooling chamber. The system may include a radiation source configured to emit a radiation beam toward the subject. The radiation source may be positioned between the first cooling chamber and the second cooling chamber such that the first cooling chamber and the second cooling chamber are outside of a radiation range of the radiation beam.

Abstract: An outlet tube includes a first rib, a second rib, and a channel positioned between the first rib and the second rib. The first rib extends from a surface of the tube. The first rib tapers between a first thickness and a second thickness. The second rib extends from the surface of the tube. The second rib tapers between the first thickness and the second thickness. The channel has a first width between adjacent first thicknesses and a second width between adjacent second thicknesses. The first width is greater than the second width.

Abstract: A prediction method for coal and gas outburst based on comparing borehole gas flow curves includes the following steps: constructing a seam-crossing borehole in the coal seam, measuring or calculating gas flow corresponding to critical gas pressure P, which is a reference gas flow Q(t)reference; performing linear regression on the reference gas flow Q(t)reference to form a reference flow curve; constructing a predicted seam-crossing borehole in a predicted area, and directly testing a gas flow at each time t in a delayed manner, which is a predicted gas flow Q(t)prediction; performing linear regression on the predicted gas flow Q(t)prediction to form a predicted flow curve; and judging whether the predicted flow curve is above the reference flow curve or whether the predicted flow curve intersects with the reference flow curve, and judging whether the coal seam in the predicted area has a risk of coal and gas outburst.

Abstract: A prediction method for coal and gas outburst based on comparing borehole gas flow curves includes the following steps: constructing a seam-crossing borehole in the coal seam, measuring or calculating gas flow corresponding to critical gas pressure P, which is a reference gas flow Q(t)reference; performing linear regression on the reference gas flow Q(t)reference to form a reference flow curve; constructing a predicted seam-crossing borehole in a predicted area, and directly testing a gas flow at each time t in a delayed manner, which is a predicted gas flow Q(t)prediction; prediction; performing linear regression on the predicted gas flow Q(t)prediction to form a predicted flow curve; and judging whether the predicted flow curve is above the reference flow curve or whether the predicted flow curve intersects with the reference flow curve, and judging whether the coal seam in the predicted area has a risk of coal and gas outburst.

Abstract: A chair chassis includes a base, a warped plate, a first adjustment member and a second adjustment member. The base including an upper cover, a lower cover and a front cover is arranged at a bottom surface of a seat of a chair. The warped plate is disposed under the upper cover of the base for connecting to a seat back of the chair. Two compression springs arranged in parallel with a certain interval are disposed between the first adjustment member and the warped plate for adjusting travel distance of the compression springs and changing a force of the seat back. The second adjustment member is used for lifting the chair by rotation of a second adjustment shaft. The chair chassis is fastened and adjusted by operating the second adjustment shaft to move along an axial direction. The chair chassis has simple structure, easy operation and improved applicability.

Abstract: A chair chassis includes a base, a warped plate, a first adjustment member and a second adjustment member. The base including an upper cover, a lower cover and a front cover is arranged at a bottom surface of a seat of a chair. The warped plate is disposed under the upper cover of the base for connecting to a seat back of the chair. Two compression springs arranged in parallel with a certain interval are disposed between the first adjustment member and the warped plate for adjusting travel distance of the compression springs and changing a force of the seat back. The second adjustment member is used for lifting the chair by rotation of a second adjustment shaft. The chair chassis is fastened and adjusted by operating the second adjustment shaft to move along an axial direction. The chair chassis has simple structure, easy operation and improved applicability.

Abstract: A chair chassis is revealed. The chair chassis includes a seat base, a middle base and an adjustment member. A sliding plate is connected to each side of the seat base. A sliding slot is arranged at a front and a rear end of each sliding plate and a pulley is arranged transversely between two sliding slots. The two pulleys connect to a tilting board. The middle base between the two sliding plates connects to the tilting board and the two sliding plates by the pulley on the front end. A third pulley slides over a slant part of the middle base. The adjustment member includes a rack, a locking piece and a lock adjustment rod for control of movement of the locking piece to be engaged with and separated from the rack. Thus users with various weights can use the same chair chassis and operate the chair chassis easier.

Abstract: A chair chassis is revealed. The chair chassis includes a seat base, a middle base and an adjustment member. A sliding plate is connected to each side of the seat base. A sliding slot is arranged at a front and a rear end of each sliding plate and a pulley is arranged transversely between two sliding slots. The two pulleys connect to a tilting board. The middle base between the two sliding plates connects to the tilting board and the two sliding plates by the pulley on the front end. A third pulley slides over a slant part of the middle base. The adjustment member includes a rack, a locking piece and a lock adjustment rod for control of movement of the locking piece to be engaged with and separated from the rack. Thus users with various weights can use the same chair chassis and operate the chair chassis easier.