滚筒式梗丝干燥加工参数的优化

为提高梗丝的加工质量特别是梗丝的丝状效果,增加梗丝与叶丝配伍性,采用正交实验方法,对滚筒式梗丝干燥加工参数(梗丝厚度、HT蒸汽压力和滚筒干燥温度组合参数)进行了分析优化,并对优化后的方案进行了验证。结果表明:1对干燥后梗丝的填充值、整丝率和丝状效果影响主次顺序均为HT蒸汽压力梗丝厚度滚筒干燥温度;2最优化加工参数为梗丝厚度0.10 mm,HT蒸汽压力0 MPa,滚筒干燥温度[筒壁温度(140±5)℃热风温度(120±2)℃],在此条件下可以提高梗丝填充值和整丝率,且对梗丝的丝状效果有明显改善;3在高档卷烟中掺配适当比例的丝状梗丝,与掺兑前相比,感官质量有所提高,焦油释放量降低约0.8mg/支。     

硫对离心铸造汽缸套切削性能的影响

一般来说,硫是有害元素。但对于灰铸铁来讲,含有少量的硫对于石墨的生核和切削性能都有非常重要的影响。在铸造生产过程中通过加入一定量的硫,提高铁液的含硫量,从而使铸件获得更好的切削性能。     

改善精梳棉条棉结的措施探讨

通过对精梳准备工序、精梳机梳理原理、牵伸工艺的分析,指出通过优化精梳准备工序的工艺、调整梳理隔距优化梳理工艺提高梳理能力、合理控制落棉率、严格温湿度控制等措施,可以有效地控制、减少精梳条棉结,减少成纱的棉结数量,提高成纱的质量水平。     

精梳锡林梳理度的研究与探讨

探讨精梳锡林梳理度对梳理质量以及成纱质量的影响.分别对由针齿组合形成的4种不同梳理度的锡林、2种不同针面包围角锡林以及3种针面包围角相同的不同型号锡林进行了纺纱对比试验.结果表明:锡林梳理度对精梳条的梳理质量,尤其是棉结、短绒影响明显.选用高性能锡林,合理配置锡林梳理度,可以达到提高梳理质量,改善精梳及成纱质量的目的.     

Determination of Local Heat-Transfer Coefficients Around a Circular Cylinder Under an Impinging Air Jet

Heat transfer coefficients around a model food shaped as a circular cylinder placed on a flat surface and impinged by a slot air jet has been determined using an inverse heat transfer method. The determination was based on time-temperature data measured with a thermocouple in the cylinder and in the air jet. The cylinder was rotated around its horizontal axis to determine the heat-transfer coefficients at different locations around the cylinder. A sensitivity analysis using Monte Carlo simulations was also performed. The local heat-transfer coefficients determined, were compared to computational fluid dynamics (CFD) simulations using the k-ω SST and RSM models. The heat-transfer coefficients determined from temperature measurements was larger than predicted by the CFD simulations. The heat-transfer rates were in better agreement on the upper part of the cylinder, including the decrease along the cylinder due to flow separation, than on the lower part close to the wake recirculation area. The SST model predicted in general a slightly higher heat-transfer rate on the upper part of the cylinder and slightly lower on the lower part of the cylinder, as compared to the RSM model.     

GSU0300—60JT气缸筒的研制

采用中温固化环氧树脂基体,无溶剂热浸胶,连续长纤维缠绕、常压固化成型以及浇注法成型耐磨层等材料、工艺制备出GSU0300—60JT气缸筒,其形状尺寸及表面质量达到设计要求。气缸筒尺寸稳定,摩擦和磨损性能优于进口原样件的(磨损量为原样件的20％)。实验证明,用上述材料,工艺,制备该气缸筒是可行的。     

卷板机卷制筒体轴辊移动调整数值计算

多年来,大型圆筒体和异径筒体的卷制工作,往往是凭经验,按工件大小规格,预先估计一个大约数值来进行轴辊的初步调整、卷制;再调整、再卷制,反复进行操作多次,直至最终卷制成型。其劳动强度大,工作效率低。本文根据卷板机的工作原理及其在卷制过程中轴辊的调整规律,用数学公式,分别推导出了三辊卷板机和四辊卷板机卷制圆筒体和异径筒体轴辊移动调整数值的计算公式,并经过实践证明是适用的。     

A closed-form solution for elastic buckling of thin-walled unstiffened circular cylinders in pure flexure

To date, despite the significant development in the field of structural mechanics, there still remains a paradox in the solutions available for a classical shell buckling problem. The difference in strength between a cylindrical shell under uniform axial compression and that under pure bending is not quite well investigated. This lack of research is reflected in the wide variations in the elastic bending strength and the slenderness limits given in current international design standards. The discrepancies in the available classical solutions and hence the design rules have initiated the current research. The main aim of this paper is to present a closed-form solution for the elastic buckling strength of unstiffened circular cylinders under pure bending using a new simplified energy approach employing the well-known Ritz method. Two types of analyses are presented for cylinders with large (D/t>200) and medium (100<D/t<200) diameter-to-thickness ratios. A unique testing rig was used to experimentally verify the new theory using a Moiré fringe film. The theoretical results are compared against the available and present test results and the existing classical solutions. The current design rules for thin-cylinders in international steel specifications are also compared, and the newly derived design curve is proposed which was found in a good agreement with the available test results.     

一种新型快速液压缸

在其活塞杆中心加一个小活塞或柱塞的一种新型快速液压缸，解决了垂直安装使用的一般液压通常存在的停止位置不准、回程速度受下行速度影响的问题。     

渐开线圆柱齿轮参数的测量与计算

针对单个渐开线斜齿圆柱齿轮的测绘问题，提出一种借助渐开线齿形，齿向检测仪来精确确定齿轮参数的方法，以实现原样测绘制造。