聚酯装置熔体过滤器的国产化改造

熔体过滤器为聚酯装置关键设备,其国产化问题一直未能解决。该文通过对天津分公司200kt/a聚酯装置熔体过滤器改造方案的介绍,探讨了其国产化条件,分析了国产熔体过滤器的结构特点,并与进口过滤器进行了对比,提出了一些看法。     

室温氯铝酸离子液体络合吸附噻吩类硫化物的研究

以室温氯铝酸离子液体作为催化剂 ,将石油一厂的直馏柴油进行预先精制 ,并且在其中加入一定量的噻吩为原料 ,在室温和氮气保护的条件下 ,考察了室温氯铝酸离子液体催化剂脱除噻吩的效果。实验结果表明 :在n(AlCl3 ) /n(BMIMCl)为 2∶1、剂油比为 0 .15、反应时间为 4 0min的条件下 ,氯铝酸离子液体对精制柴油中的噻吩脱除率可达到 4 6 % ,从而说明氯铝酸离子液体具有很好的吸附噻吩类杂环化合物的能力。虽然氯铝酸离子液体对水和空气敏感、不稳定 ,但是可以再生重复循环使用     

铰链四杆直线机构综合的新方法

给出一种综合连杆曲线具有四个无限接近点（鲍尔点）直线的四杆机构的新方法，用该方法综合铰链四杆机构可事先给定钦逼近直线上的点、直线方向以及机架的位置，而且在每种给定条件下，都可以得到无穷多种机构供设计者选择。     

低渗透率油藏压裂直井稳态解产能公式研究

在数值模拟结果分析的基础上,半压裂直井近似为一条垂直裂缝。采用拟三维的思想及保角变换方法,推导出垂直裂缝的产能公式,并将本文公式的计算结果与Ｊｏｓｈｉ、Ｃｉｇｅｒ、Ｇｕｏ以及数值结果进行对比。本文公式可满足压裂直井产能估算的要求。     

How to draw free trees inside bounded rectilinear polygons

Drawing graphs on a 2D grid with prescribed size is NP-complete, even if we restrict ourselves to planar orthogonal grid drawings of trees. In this paper, we introduce a new algorithm for polyline drawing of free trees on 2D grids which are bounded by rectilinear polygons. Our algorithm uses straight skeleton and simulated annealing and aims to distribute the vertices of the given trees uniformly on the given bounded grids. Our experimental results show that our algorithm is relatively successful to achieve uniform distribution of the nodes of the given trees. To our knowledge, this paper is the first attempt to develop algorithms that draw trees on restricted 2D grids which are bounded by simple rectilinear polygons.     

Effect of straight vegetable oil blends and biodiesel blends on wear of mechanical fuel injection equipment of a constant speed diesel engine

Vegetable oils and biodiesel have emerged as strong alternative fuels worldwide. However use of new fuels in existing engines leads to issues such as wear of vital moving components, and fuel injection equipment (FIE). It is important to ensure that new alternative fuel does not affect the FIE adversely. In this experimental study, a non-firing engine FIE simulator test rig prototype was developed and 250 h endurance test of FIE was performed with an objective to ensure the long-term compatibility and durability of biofuel blends. The components of FIE such as plunger, nozzle needle, valve, and valve holder were investigated for wear. Test fuels used in this study were Karanja blends (K20, K5), Jatropha blends (J20, J5), Biodiesel blends (B20, B5) and baseline mineral diesel in a non-firing engine FIE simulator. The compatibility of FIE with test fuels in terms of dimensional loss, weight loss and surface texture variations using optical microscopy before and after the endurance test was compared. Biodiesel blends showed relatively lower wear compared to mineral diesel however SVO blends showed no definite trend of the wear results compared to baseline mineral diesel.     

Available friction of ladder shoes and slip potential for climbing on a straight ladder

Straight ladder accidents are a major safety problem. As a leading cause of injuries involving straight ladders, slips at the ladder base occur when the required friction exceeds the available friction at the ladder shoe and floor interface. The objectives of this experiment were to measure the available friction at the base of a portable straight ladder in contact with a floor and to estimate the slip potential of the ladder. The results of friction measurements indicated that the measured friction coefficient on the oily surfaces differed among the six commercially available ladder shoes evaluated. A statistical model was used to compare the available friction results from the current study with the friction requirements under different climbing conditions from a previous study based on their stochastic distributions to estimate the slip potential at the base of the ladder. The results showed that different climbing conditions used in the previous study could be supported by available friction on dry surfaces. However, when the ladder was put onto oily surfaces, resulting in a significant reduction in the available friction due to contamination, slip potential was significantly increased.     

基于AutoCAD和VB的非圆曲线零件铣削自动编程

目前数控加工所需的数控程序普遍采用数控自动编程。针对AutoCAD软件设计的非圆曲线零件,提出了一种数控加工代码自动生成方法。利用VB作为二次开发工具,对AutoCAD软件进行开发,使其能够识别零件轮廓中的直线、圆弧和非圆曲线,然后用VB读取非圆曲线的轮廓特征参数;利用VB实现数控编程中非圆曲线的等误差直线逼近,最后自动生成数控加工程序,从而实现非圆曲线零件的铣削自动编程。     

利用鲍尔点求解直线导路机构方法的研究

依据鲍尔点理论建立了鲍尔点数据库 ,解决了给定点位和直线方向条件下的直线导路综合问题 ,且运用该方法可得到多组满足要求的曲柄摇杆机构     

利用Beamlet变换算法提取遥感图像直线

遥感图像处理中,直线特征是一种极为重要的特征,能够提供重要的视觉感知线索。本文利用一种Beamlet变换算法来提取遥感图像中的直线特征,通过对遥感图像按二进、递归进行划分,利用灰度信息,积分计算每一小块图像中的Beamlets,结合梯度信息,通过广义似然比检验GLRT（Generalized Likelihood Ratio Testing）来检测判断符合条件假设的Beamlets,重建目标直线。此算法可以克服图像中的干扰及噪声,适应复杂、低信噪比遥感图像环境,准确地定位出直线。实验结果表明,这种算法具有较好的性能,可以应用到实际的遥感图像处理中,具有实用价值。