Successful treatment of two horses after perforation of the small intestine by fine wire

This paper describes the successful surgical management of two horses with fine wire penetration of the small intestine. Exploratory laparotomy in Case 1 revealed an adhesion between adjacent loops of jejunum. Dissection of the adhesion revealed a small length of fine wire. In Case 2, exploratory laparotomy revealed a dense adhesion between the jejunum and the ventral abdominal wall. Dissection of the adhesion also revealed fine wire extending from the jejunum. Neither case required intestinal resection, and both horses made uncomplicated recoveries from the surgical procedures and were discharged 5 days after surgery.     

关于立式绕线机拉力与单饼式线圈尺寸关系的分析

文章着重分析了立式绕线机的拉力设定与变压器单饼式线圈绕制后外型尺寸、导线线规变化情况以及线圈紧密度的关系。通过适当调整立式绕线机的拉力,从而调整线圈B端尺寸,解决现今线圈B端尺寸存在的问题。     

Design calculation and finite element simulation analysis of stranded wire helical springs

The spatial structure of single wire is analyzed based on the forming process of stranded wire helical springs. Additionally,three parameters are derived from the existing foundation,including distribution circle radius of strand,spiral parameter of single wire and track scanning parameter. The aided design method of stranded wire helical springs based on feature scanning is put forward in which the centerline model of single wire can be obtained through one scanning step and the modeling method is given based on PROE code. The simulation analysis for spring in loading is performed by using ABAQUS code based on the calculation results. The finite element analysis results show the stress-strain ability of wire and the stress distribution of the section. The affects of loading rate on vibration of coils is also found.The results can make up for the deficiency of existing methods and give more beneficial assistance for production processing and performance test of the stranded wire helical springs.     

基于DF2204无级变速拖拉机的农机无人驾驶系统研制

针对农机无人化作业需求,该研究基于DF2204无级变速拖拉机和机器人操作系统（Robot Operating System,ROS）,研发了一种适于田间作业的农机无人驾驶自主作业系统。系统由控制、规划、安全和总线通信等模块组成。对DF2204无级变速拖拉机进行硬件改造与集成,设计满足农机无人驾驶要求的控制器局域网（Controller Area Network,CAN）总线协议和ROS与CAN总线通信的消息结构,包括5类控制帧和2类状态帧;设计了基于比例-积分-微分（Proportion Integration Differentiation,PID）控制器的横向跟踪与纵向速度控制算法。在北京密云试验田开展田间小麦播种实际作业试验。试验结果表明,消息结构满足50 Hz通信负载,横向跟踪平均绝对误差为2.96 cm,纵向速度平均绝对误差0.68 m/s。研究结果可为无级变速拖拉机的无人化升级改造提供参考,提高农机智能化水平和作业效率。     

快走丝线切割机床断丝故障分析与对策

对快走丝线切割机床断丝故障发生的原因进行了全面分析,并根据不同的断丝原因提出了相应的预防对策。     

山地果园无动力运输机设计

针对大坡度山地果园运输难、耗能高的问题,设计1种依靠货物自身重力运输的山地果园无动力运输机。运输机主要由自适应阻尼装置、遥控急刹装置、遥控控制系统、增速装置、冷却风扇、运输车等组成,能实现一端运输车在货物重力作用下沿20°~50°坡地或直线水泥槽内安全匀速下行,另一端带着空运输车上行。该运输机仅需1个12V电瓶提供遥控制动时所需动力,通过遥控器遥控急刹装置,能实现运输机在任意点的启停。试验表明,在长时间运行时,维持制动毂温度小于50℃状态下,运输机能稳定以最大速度0.7 m/s匀速运行,最大载荷为1t。该运输机工作可靠、运行平稳、操作简单、无需运输动力,适合偏远大坡度山地果物的运输,节能环保。     

小径级杉木制备内置碳纤维电热线地热地板

以小径级杉木六棱柱体锯制的层板为芯层和底层,并在芯层内置碳纤维电热线,制备三层结构地热地板,测试在不同电压下地板的导热性能和尺寸稳定性.结果表明:试板经0.5h左右即达到平衡温度,最终可达30～35℃,表面温度分布均匀,电压的提高有助于地板的导热效能,并能够显著提高地板最终平衡温度;组坯方式对地板面层温度及尺寸稳定性均无明显影响,但对传热稳定性有一定影响;长时间加热时地板的尺寸稳定性有待提高.     

A comparison of the withdrawal resistance load of nails using experimental and interference approaches

Abstract

The objective of this study was to determine and predict the withdrawal resistance or pull-out load of common wire nails embedded in radial, tangential and cross-sectional grain orientation of Douglas fir (Presudotsuga menziesii) and sugar maple (Acer sacharum) samples. Four lead-hole diameters of 1.5, 2.0, 2.5 and 3.0 mm were used to create various interference fits. Nails with a diameter of 3.38 mm were driven into the samples to a depth of 10 mm for the experiments. The overall withdrawal resistance of Douglas fir samples was found to be lower than that of maple samples. Strength values of each sample increased with decreasing lead-hole diameters. No significant difference was found between withdrawal resistance values from radial and tangential sections in either species. However, significantly lower values were obtained for the cross-sections of the samples than for the two other sections. Ratios between predicted pull-out load values of the nails from both species based on the finite element numerical interference approach were very close to experimental measurements, with ratios ranging from 0.93 to 1.09. The results provide better understanding of the behaviour and performance of pull-out resistance for building systems.     

不同加温装置对冬季黄瓜育苗和生长的影响

利用加温线和发热膜进行了冬季黄瓜育苗和栽培试验。结果表明,温控相同条件下,加温线的耗电量大于发热膜,发热膜苗床上的基质温度首先达到温控最高点,且一天中变化幅度较平稳。发热膜苗床上春秋王、沪杂3号、沪杂6号黄瓜品种幼苗的下胚轴长、子叶长和宽都大于加温线苗床上的幼苗。定植后的3个处理中,植株叶长、叶宽、叶片数、株高和单株产量表现为发热膜处理>发热膜+小环棚处理>加温线处理。因此利用发热膜进行冬季茄果类育苗,不仅省电而且加热能力和保温效果好。     

基于DSPic30F2020的送丝机的研究

设计一种基于DSPic30F2020微控制器的数字化送丝机,送丝机采用无刷直流电机驱动,送丝速度直接由送丝电机反馈。送丝机采用基于电流反馈和速度反馈的双闭环控制,控制精度高,稳定性好。送丝机提供RS485通信接口,便于实现数字化通信。