Abstract: Disclosed are a crystal form and a pharmaceutically acceptable salt of a ketohexokinase inhibitor, a preparation method therefor, and a pharmaceutical composition and use thereof, which specifically relate to a crystal form of a compound of formula (1), a pharmaceutically acceptable salt of the compound of formula (1), and a crystal form of the pharmaceutically acceptable saltserving as the KHK inhibitor, a preparation method therefor, a pharmaceutical composition containing the crystal form, the pharmaceutically acceptable salt, and the crystal form of the pharmaceutically acceptable salt, and use of the crystal form and the pharmaceutically acceptable salt of the compound of formula (1), and the crystal form of the pharmaceutically acceptable salt in the preparation of a medicament for treatment and/or prevention of a KHK-mediated disease or related disease.

Abstract: A kind of variable engine valve control system with pressure difference comprises hydraulic supply equipment, hydraulic actuator apparatus, valve and spring controlling piston balance. The hydraulic actuator comprises hydraulic cylinder, piston and piston rod. The piston rod is coupled and moved with the valve. It is characterized by that the said piston divides the hydraulic cylinder into upper chamber and lower chamber. The said hydraulic supply equipment is connected with the upper chamber of the hydraulic cylinder through the fluid inlet pipe and the said lower chamber of the hydraulic cylinder is connected with the hydraulic supply equipment through the pressure difference proportional relief valve.

Abstract: A three-way proportional pressure reducing valve includes a valve body and a cylindrical valve spool. Five chambers are formed between the valve body and the cylindrical valve spool, respectively a fifth chambers, a first chamber, a second chamber, a third chamber and the fourth chamber. The first chamber connected to a high pressure inlet port P, the second chamber connected to a oil port A and the third chamber connected to a low pressure outlet port T. A first control edge being fitted between the first chamber and the second chamber, a second control edge being fitted between the second chamber and the third chamber. A first passage being located between the fifth chamber and the second chamber for connecting the second chamber to the fifth chamber, a second passage being located between the fourth chamber and the third chamber for connecting the fourth chamber to the third chamber.

Abstract: A kind of variable engine valve control system with pressure difference comprises hydraulic supply equipment, hydraulic actuator apparatus, valve and spring controlling piston balance. The hydraulic actuator comprises hydraulic cylinder, piston and piston rod. The piston rod is coupled and moved with the valve. It is characterized by that the said piston divides the hydraulic cylinder into upper chamber and lower chamber. The said hydraulic supply equipment is connected with the upper chamber of the hydraulic cylinder through the fluid inlet pipe and the said lower chamber of the hydraulic cylinder is connected with the hydraulic supply equipment through the pressure difference proportional relief valve.