用于PET薄膜回收的螺杆设计

根据PET薄膜的特点和高分子熔融态流动理论，分析了挤出回收用螺杆的各段结构，及螺杆参数选择，设计出大长径比、深槽、双排气、高效专用螺杆。     

稀磷酸澄清槽泥浆泵改用单螺杆泵的实践

磷酸生产中输送稀磷酸澄清槽淤渣的泥浆泵，各厂的运行情况都不够理想。介绍了三种类型泥浆泵的运行情况，针对淤渣中会出现块结垢物影响泥浆泵长期运行，在单螺杆泵进料腔内设置破碎送料器后，取得了较理想的效果，从而提高了磷酸装置的运转率和磷得率。     

双螺杆转速差决定的螺杆间隙之探讨

根据相对运动原理计算了同向旋转双螺杆因螺杆转速差决定的两螺杆之间的径向和轴向间隙,可为工程上设计这些间隙时提供参考。     

基于KPCA和SVM的火箭发动机试验台故障诊断方法

为了解决液体火箭发动机试验台的故障诊断问题,提出了一种基于核主元分析(KPCA)特征提取和支持向量多分类机(SVM)的故障诊断方法,该方法首先利用核主元分析对试验台标准故障样本进行特征提取,通过特征分析,建立适合于试验台故障状态识别的层次多分类支持向量机,并对其进行训练,然后将试验数据在主元上投影,输入到训练好的支持向量多分类器,对试验台故障状态进行识别.该方法充分利用了核主元分析强大的非线性特征提取能力和支持向量分类机良好的小样本泛化特性,解决了试验台故障诊断中的小样本、非线性模式识别问题.对试验台的试验结果表明,该方法是有效的、可行的.     

螺纹桩在软弱地层中的应用

分析了螺纹桩的受力机理,探讨了螺纹桩单桩承载力的确定方法,指出螺纹桩单桩承载力高、节约材料显著、能充分利用地基土的特性,在软弱地层中的应用优势显著,并通过实际工程实例给予具体说明.     

Effect of surface coating on the screw loosening of dental abutment screws

Regardless of the type of performed restoration, in most cases, a screw connection is employed between the abutment and implant. For this reason, implant screw loosening has remained a problem in restorative practices. The purpose of this study was to compare the surface of coated/plated screws with titanium and gold alloy screws and to evaluate the physical properties of coated/plated material after scratch tests via FE-SEM (field emission scanning electron microscopy) investigation. GoldTite, titanium screws provided by 3i (Implant Innovation, USA) and TorqTite, titanium screws by Steri-Oss (Nobel Biocare, USA) and gold screws and titanium screws by AVANA (Osstem Implant, Korea) were selected for this study. The surface, crest, and root of the abutment screws were observed by FE-SEM. A micro-diamond needle was also prepared for the scratch test. Each abutment screw was fixed, and a scratch on the surface of the head region was made at constant load and thereafter the fine trace was observed with FE-SEM. The surface of GoldTite was smoother than that of other screws and it also had abundant ductility and malleability compared with titanium and gold screws. The scratch tests also revealed that teflon particles were exfoliated easily in the screw coated with teflon. The titanium screw had rough surface and low ductility. The clinical use of gold-plated screws is recommended as a means of preventing screw loosening.     

滚珠丝杠的智能化研究进展

数控机床进给系统的智能化的状态检测、故障诊断以及自修复的能力可以提高数控机床工作的稳定性和可靠性,减少数控机床加工过程中出现的问题。滚珠丝杠是数控机床进给系统的重要组成部分,其精度与性能直接影响着数控机床的加工质量,滚珠丝杠的智能化发展也对数控机床的智能化发展有着非常重要的作用。综述了滚珠丝杠智能化的研究现状,分析了滚珠丝杠的动态测量和静态测量区别及优缺点;概述了基于数学模型和基于人工智能两个方面的故障诊断技术在滚珠丝杠中的应用;阐述了滚珠丝杠弹流润滑的机制以及通过润滑剂添加剂进行自修复的方法,阐明了滚珠丝杠的状态检测与故障诊断技术及自修复技术所存在的问题,展望了滚珠丝杠智能化的发展方向。     

用过期“双迫”发射药改制射钉枪药的研究

文章分析了将过期“双迫”药改制成射钉枪药的可行性．实验表明,改制可采用球形药工艺,制品能满足射钉枪的使用要求．     

Comparison of multiple linear regression and artificial neural network in developing the objective functions of the orthopaedic screws

Optimizing the orthopaedic screws can greatly improve their biomechanical performances. However, a methodical design optimization approach requires a long time to search the best design. Thus, the surrogate objective functions of the orthopaedic screws should be accurately developed. To our knowledge, there is no study to evaluate the strengths and limitations of the surrogate methods in developing the objective functions of the orthopaedic screws. Three-dimensional finite element models for both the tibial locking screws and the spinal pedicle screws were constructed and analyzed. Then, the learning data were prepared according to the arrangement of the Taguchi orthogonal array, and the verification data were selected with use of a randomized selection. Finally, the surrogate objective functions were developed by using either the multiple linear regression or the artificial neural network. The applicability and accuracy of those surrogate methods were evaluated and discussed. The multiple linear regression method could successfully construct the objective function of the tibial locking screws, but it failed to develop the objective function of the spinal pedicle screws. The artificial neural network method showed a greater capacity of prediction in developing the objective functions for the tibial locking screws and the spinal pedicle screws than the multiple linear regression method. The artificial neural network method may be a useful option for developing the objective functions of the orthopaedic screws with a greater structural complexity. The surrogate objective functions of the orthopaedic screws could effectively decrease the time and effort required for the design optimization process.     

同向双螺杆挤出机的共混技术

本文论述了聚合物共混须用同向双螺杆挤出机的原理、特征及不同物料的共混技术。