Abstract: Disclosed are a high-selectivity KCNQ4 potassium channel agonist of formula I, a preparation method therefor and the use thereof. The compound further improves the KCNQ4 agonistic activity, and is still free of KCNQ2 agonistic activity, thus having excellent KCNQ4/KCNQ2 selectivity. The high-selectivity KCNQ4 agonist overcomes the defect of poor selectivity of existing potassium channel agonists, the activity is relatively increased, and the toxicity is remarkably reduced. The agonist also has a simpler structure and lower product cost, thereby having a better development prospect.

Abstract: Provided in the present invention are an isoquinoline alkaloid compound selected from the group consisting of the compounds represented by the following structural formulas, and a preparation method therefor and the use thereof. The present invention proves for the first time that the isoquinoline alkaloid compound is an inhibitor of the IK potassium current and the background potassium current in the nervous system, the cardiovascular system and the pancreas, especially an inhibitor of the Kv2.1 channel and the TRESK channel, and can be used for treating a disease such as stroke, arrhythmia, atrial fibrillation, diabetes, pain, hypoventilation, and depression.

Abstract: A vertical high-speed testing device for a spiral seal of a cone bit bearing is provided. The device includes an upper fixed plate, a liquid cylinder, a cone, a spiral sleeve, a shaft and a lower fixed plate. The spiral sleeve is in threaded connection to the cone. Both the cone and the spiral sleeve are sheathed on the shaft. Sealing threads are provided on an inner surface of the spiral sleeve, and there is a clearance between the sealing threads and the shaft. By the testing device, a spiral seal structure for a cone bit bearing is simulated, and the cone drives the spiral sleeve to rotate; and the sand draining performance of the spiral seal is tested by measuring the time required to drain sand-containing medium.

Abstract: A horizontal high-speed testing device for a spiral seal of a cone bit bearing is provided. The device comprises a shaft, a spiral sleeve and a cone. The spiral sleeve is in threaded connection to the cone. Sealing threads are provided on an inner diameter of the spiral sleeve. Both the spiral sleeve and the cone are sheathed on the shaft. By the testing device of the present invention, a spiral seal structure for a cone bit bearing is simulated, and the cone drives the spiral sleeve to rotate; the sand draining performance of the spiral seal can be tested in two ways, i.e., by measuring the time required to drain the sand-containing liquid and by measuring the weight of drained sand, so that the smooth production and application of spiral seal products can be assured.

Abstract: A horizontal high-speed testing device for a spiral seal of a cone bit bearing is provided. The device comprises a shaft, a spiral sleeve and a cone. The spiral sleeve is in threaded connection to the cone. Sealing threads are provided on an inner diameter of the spiral sleeve. Both the spiral sleeve and the cone are sheathed on the shaft. By the testing device of the present invention, a spiral seal structure for a cone bit bearing is simulated, and the cone drives the spiral sleeve to rotate; the sand draining performance of the spiral seal can be tested in two ways, i.e., by measuring the time required to drain the sand-containing liquid and by measuring the weight of drained sand, so that the smooth production and application of spiral seal products can be assured.

Abstract: A vertical high-speed testing device for a spiral seal of a cone bit bearing is provided. The device includes an upper fixed plate, a liquid cylinder, a cone, a spiral sleeve, a shaft and a lower fixed plate. The spiral sleeve is in threaded connection to the cone. Both the cone and the spiral sleeve are sheathed on the shaft. Sealing threads are provided on an inner surface of the spiral sleeve, and there is a clearance between the sealing threads and the shaft. By the testing device of the present invention, a spiral seal structure for a cone bit bearing is simulated, and the cone drives the spiral sleeve to rotate; and the sand draining performance of the spiral seal is tested by measuring the time required to drain sand-containing medium, so that the smooth production and application of spiral seal products can be assured.