旋割法制备气管螺旋条评价

目的通过改进螺旋剪法建立制备气管螺旋条的旋割法。方法 40只豚鼠,用旋割法和螺旋剪法制备离体豚鼠气管螺旋条,在Kreb's液中平衡孵育2 h后,以组胺histamine(浴槽浓度2.0×10-3g/L)和乙酰胆碱acetylcholine(浴槽浓度2.0×10-4g/L)引发气管螺旋条收缩,用BL420生物信号采集系统与张力传感器测定标本张力变化值。数据采用SPSS11.5软件在α=0.05的信度下进行t检验。结果 2 g负荷下,旋割法标本histamine引发收缩幅度是螺旋剪法制备标本的1.31倍,乙酰胆碱引发收缩幅度旋割法是螺旋剪法制备标本的1.208倍,经t检验,P<0.05,差异均具有显著性;旋割法标本,histamine引发2 g负荷标本收缩幅度是1 g负荷的1.48倍,乙酰胆碱引发2 g负荷标本的收缩幅度是1 g负荷的1.38倍,经t检验,P<0.05,差异均具有显著性;旋割法标本经hista-mine或acetylcholine激发收缩,洗净药物重复激发6次收缩幅度的RSD值分别为19.8%和19.1%,螺旋剪法标本经histamine或acetylcholine 6次重复引发诱发收缩幅度的RSD值分别35.3%和33.7%。结论与螺旋剪法制备气管螺旋条标本比较,旋割法制备螺旋条标本对收缩诱导剂histamine与acetylcholine的敏感性高,标本负荷以2 g较好,旋割法标本重复利用收缩幅度变化值较螺旋剪法标本小。

Longhole waterjet rotary cutting for in-seam cross panel methane drainage

In order to improve the efficiency of gas drainage before and during longwall extraction,a waterjet rotary cutting system has been developed for in-seam cross panel methane drainage.The purpose of the water rotary cutting system developed was to create artificial fractures along the gas drainage boreholes.During the design of the system,it was perceived that the nozzle geometry is one of the key factors,affecting cutting capacity.Therefore,we studied the structural and geometric parameters of the nozzle and optimized its performance during laboratory tests and numerical simulation.Underground trials conducted in a coal mine,indicate that production of gas drainage before and after cutting significantly increased by up to three times.The advantages of waterjet assisted gas drainage method has been identified as:1) increasing gas drainage efficiency,2) a possible development of a gas drainage fractured network within coal seams associated with panel extraction,and 3) reducing the risk of exceeding gas limits during longwalling.