小型单螺杆挤压膨化机加工全脂大豆的试验

利用自行研制的小型单螺杆挤压膨化机对全脂大豆进行膨化加工试验,将大豆物料含水率、螺杆转速、膨化温度作为试验因素,经过单因素试验和二次回归正交旋转组合试验,找出其对大豆膨化加工性能(度电产量、生产率、膨化压力)的影响规律,并经优化设计得出最佳参数组合。利用扫描电子显微镜观察和分析膨化及未膨化大豆的微观结构变化,对大豆膨化机理进行了初步探讨,并通过膨化和未膨化大豆的营养成分对照测试分析,证实了挤压膨化能够改善大豆的理化性状和营养成分,有利于动物的消化和吸收。     

带悬板排沙漏斗三维流场测试

本文首次利用激光多普勒测速仪（ＬＤＡ）测试了排沙漏斗的三维螺旋流流场，并对其时均流特性及紊动特性进行了分析。     

钢球滚子弧面分度凸轮载荷分布

运用空间啮合原理和回转张量法,推导出凸轮滚道截形采用双圆弧结构时,钢球滚子弧面分度凸轮的廓面方程和啮合方程.应用赫兹接触理论和变形协调条件,推导出载荷在每个参与啮合钢球中的分配关系.通过实例计算,发现每个钢球上的载荷大小分配不同,在钢球的啮入、啮出点,钢球受力发生突变,参与啮合的钢球数目越多,每个钢球的受力越小.     

圆柱螺纹牙型非接触检测失真校正

在对圆柱螺纹进行非接触检测时,螺纹牙型会产生失真现象,为此提出图像校正的方法。从螺纹牙型失真的几何原理出发,建立相应的螺纹数学模型,对采集的螺纹图像进行校正,获得真实的螺纹牙型,并通过软件仿真和试验验证了该模型的正确性。同时表明图像校正的方法提高了圆柱螺纹非接触检测的精度、效率。     

正反螺旋式土壤改良石灰播撒机设计与试验

为了提高石灰播撒的效率和精准控制播撒量,研制了正反螺旋式石灰播撒机,并与旋耕机组合成一体机,采用复合作业方式。该文论述了正反螺旋式石灰播撒机的结构和工作原理、灰量调节机构原理和调节方法,并对播撒机的出灰口尺寸和播撒辊的转速进行了试验设计,计算了播撒机的总功率;最后将石灰播撒旋耕机一体机在冬天的稻田进行石灰播撒-旋耕组合的田间试验。结果表明:当石灰播撒-旋耕一体机前进速度平均为5 km/h,播撒辊转速为80 r/min,调节机构档位处于最大播撒量的13档时,满足第1年的播撒量要求;当档位分别位于12档(或10档)和7档时,播撒量分别满足第2年和第3年的播撒量要求。该研究为改善农业作业条件、降低劳动力成本、提高石灰播撒效率提供了参考。     

螺杆挤压膨化机加工农作物秸秆的试验研究

利用小型自热式单螺杆挤压膨化机对农作物秸秆进行膨化加工试验。将螺杆螺距、喷嘴出口间隙、秸秆物料含水率、秸秆物料粒度作为试验因素，经单因素试验和二次通用旋转组合试验找出其对秸秆膨化加工性能(膨化压力、生产率、度电产量等)的影响规律，并经优化设计得出最佳参数组合。利用电子显微扫描观察和分析膨化及未膨化玉米秸、豆秸的微观结构的变化，对农作物秸秆膨化机理进行了初步探讨，并通过膨化和未膨化玉米秸、豆秸的营养成分对照测试分析，证实了秸秆膨化能够改善秸秆的理化性状和营养成分，为提高秸秆的利用率和可消化率创造了条件。     

大尺寸变螺距丝杠的数控加工

在数控车床上串联使用两套数控系统进行多坐标的联动控制,优化渐变螺距丝杠螺距拐点处的结构加工,实现渐变螺距丝杠的数控加工;通过实现刀具沿丝杠工件轴线的变速直线运动和丝杠工件的变速旋转运动,来进行匀变螺距丝杠数控加工,扩展了数控技术的应用和数控车床的加工范围。     

车齿原理与刀具设计的研究

In this paper, the principle to form curves and curved surfaces by gear turning is put forward. The designing principle and calculating formulas of the cutter with arbitrary teeth profile for gear turning is derived from the processing of the cylindrical     

In vitro evaluation of screws and suture anchors in metaphyseal bone of the canine tibia

OBJECTIVE: To compare ease of insertion, load to failure, and mode of failure of cortical and cancellous screws, BoneBiter, IMEX, and TwinFix suture anchors in canine metaphyseal tibial bone. STUDY DESIGN: Experimental biomechanical study. ANIMALS: Canine cadaveric tibias. METHODS: One investigator inserted all anchors and subjectively evaluated ease of placement. Anchor systems were loaded to failure along axis of insertion with audio-video recording to determine failure mode. RESULTS: BoneBiter was the most difficult anchor to insert successfully. Mean+/-SD loads to failure were cancellous screw (711+/-193 N), IMEX 4.7 mm 18 g wire (661+/-163 N), IMEX 4.0 mm 18 g wire (661+/-165 N), cortical screw (635+/-184 N), BoneBiter #5 Kevlar suture (393+/- 109 N), and TwinFix 5.0 mm #2 polyester (267+/-73 N). No significant differences were noted among the cortical screw, cancellous screw, IMEX 4.7 and 4.0 mm, all of which were significantly (P<.001) greater than BoneBiter and TwinFix . Failure modes were pullout of bone, suture-wire breakage, eyelet breakage, or no failure to 1000 N: screws (18,0,0,2), IMEX (18,1,1,0), BoneBiter (2,8,0,0), and TwinFix (0,10,0,0). CONCLUSIONS: Fixation devices were user friendly, with the exception of BoneBiter. Mode of failure is dependent on suture material and anchor design. Cortical and cancellous screws, and IMEX anchors with 18 g wire have significantly greater load to failure compared with BoneBiter and TwinFix suture anchors. CLINICAL RELEVANCE: Based on load to failure, ease of use, design characteristics, and cost, IMEX anchors may have advantages over other comparable soft tissue fixation devices.     

Canine sacroiliac luxation: anatomic study of dorsoventral articular surface angulation and safe corridor for placement of screws used for lag fixation

OBJECTIVE: To define a safe corridor in the dorsoventral plane to facilitate placement of screws inserted in lag fashion within the sacral body for fixation of sacroiliac fracture-luxation injuries in dogs. STUDY DESIGN: Anatomic study. SAMPLE POPULATION: Cadaveric canine sacra. METHODS: Canine sacra (n=45) were used for a radiographic study to define a safe corridor in the dorsoventral plane for placement of screws inserted in lag fashion for fixation of sacroiliac luxation in the dog. The defined safe corridor allowed drilling to a depth of 65% of the sacral width to ensure screw purchase of > or =60%. Effects of positioning and measurement techniques were evaluated. RESULTS: Eighty-seven safe corridors were measured. The mean articular surface was 100+/-4.52 degrees from horizontal. Mean maximum, optimum, and minimum safe corridor drill angles were 111+/- 4.57 degrees, 100+/-4.70 degrees, and 89+/-5.17 degrees, respectively, from the articular surface. Predicted surgeon error of +/-4 degrees was used to define the safe corridor for use clinically. CONCLUSIONS: In 91% of sacra, a drill angle of 100+/-4 degrees would remain ventral to the vertebral canal. Twelve sacra (14%) were at risk of penetration of the pelvic canal. A drill angle of 97+/-4 degrees avoids penetration of the vertebral canal in all sacra measured but risks ventral exit from the body in 30% of sacra studied. CLINICAL RELEVANCE: A drill angle of 97 degrees from the articular surface is recommended for insertion of screws for lag fixation of canine sacroiliac luxation.