基于激光三角测量的镰刀弯在线检测系统

镰刀弯是板带生产过程中常见的板形缺陷,在线测量镰刀弯是实现板形控制的前提条件。本文建立一种基于激光三角测量法的镰刀弯在线检测系统,由激光发射器、线阵CCD、接收镜头组成激光测量箱,检测钢板边部的位置和倾斜量;同时由激光测速仪检测钢板的长度位置,形成边部轮廓曲线。通过边部倾斜量对轮廓曲线进行纠正,消除钢板侧向移动引起的误差。系统计算得出镰刀弯参数,同时提供板带宽度、长度等数据。实际应用中,根据测量数据进行生产参数调整,有效提高了板形质量。     

基于向量的带钢缺陷检测算法

介绍了用计算机视觉检测系统中的图像处理技术检测带钢的边裂以及孔洞。首先识别带钢图像的轮廓,得到带钢边部、孔洞的轮廓曲线向量编码,然后利用向量的点积计算轮廓的弯曲程度,据此作为判断条件,检测边裂与孔洞缺陷。实验结果表明：该方法应用到实际检测系统中,能够可靠地检出带钢的边裂。     

拉矫机带钢反弯曲率的计算方法

对于拉伸矫直机,带钢在矫直机辊子上的曲率半径的计算尤为重要,只有确定了该曲率半径,才能进一步计算带钢的反弯曲率、弹复曲率和残留曲率,进一步计算带钢的平直度。假定带钢在矫直辊上的曲线为抛物线,给出带钢反弯曲率半径的计算方法,并且进一步讨论矫直辊辊子直径的计算方法。     

联合拉拔机双面凸轮曲线的研究

本文根据双面凸轮在联合拉拔机的动力传动的应用，分析了凸轮曲线的方程，运用优化方法确定曲线参数。     

结晶器在线调宽速度曲线算法研究与仿真

以变速-变锥式调宽运动轨迹为基础,分析了其调宽运动轨迹的缺陷,提出了根据调宽范围自适应调节的速度曲线算法,并开发了在线调宽速度曲线预设定系统。通过向该系统中输入从连铸现场采集到的工艺数据,可以计算出速度曲线算法中所有的关键参数和调宽过程步骤的设定值,并可绘制出调宽过程参数变化的仿真曲线。该速度曲线算法能够自动选择调宽方式并达到了调宽目标值,技术人员在调宽生产之前就能了解整个调宽过程和关键参数,保证调宽生产的安全性。     

弹性芯理论对正确制定矫直规程的作用

简要介绍了矫直反弯曲率半径的计算过程,研究了弹性芯理论,得出了条材(包括棒材,板材,型材,带材)弯曲隐患与弹区比之间的函数关系曲线,通过该曲线选择合适的弹区比来控制弯曲隐患的大小,从而确定反弯半径并制定正确的矫直规程,提高矫直精度和产品质量.     

关于用取芯—回弹法建立武钢老厂区测强曲线的探讨

本文从科研和工程检测实际工作出发，简述了建立武钢老厂区测强曲线的目的和意义，分析了该地区的环境特点，并与《规程》推荐的测强曲线及使用环境进行了比较。提出了用取芯－回弹方法建立测强曲线的方法。最后，用实测资料进行回归计算，提出了武钢厂区的测强曲线及其方程。     

吐丝机吐丝曲线的设计及力能参数的分析

采用ｒ、ｚ方向双函数拟合吐丝管曲线，给出了钢材轴向力及吐丝机负载力矩、负载功率的计算方法。分析中吐丝管曲线各参数对钢材轴向力及负载力矩，负载功率的影响，影响了各参数的选择方法。为准确地设计吐丝管曲线和计算吐丝机力能提供了理论依据。     

道岔附带曲线养护整正的方法改进

文章介绍了道岔附带曲线的概念及头尾的确定,各各点支距的计算和现场测设步骤,并确定了拨道整正方法。说明了附带曲线的方向、位置正确与否,直接影响行车安全与平稳,得出了道岔与附带曲线一起保养的结论。     

热连轧机支承辊辊型曲线多目标优化设计研究

以850 mm四辊热连轧机组为研究对象,建立了轧辊辊间接触压力和板形计算模型,以均匀辊间接触压力分布和带钢板形良好为目标,对热连轧机精轧机组支承辊辊型曲线进行了多目标优化设计。理论计算表明,优化后的支承辊辊型曲线均匀了辊间接触压力分布,降低了辊端接触压力峰值,同时能够提高弯辊力对板形的控制效果。工业生产试验后正式推广使用,支承辊掉肩和掉肉现象得到了有效遏制,带钢板形良好。     

Learning curve for oesophageal cancer surgery

BACKGROUND: Surgical training and experience are frequently claimed to influence early and late outcome measures. The aim of this study was to examine any improvement in an individual surgeon's performance in one operation over a period of 7 years from initial appointment to date. METHODS: Patients undergoing Ivor Lewis subtotal oesophagectomy performed by a single surgeon between April 1990 and December 1996 were identified from a prospectively compiled oesophageal cancer database. Operating time (abdominal, thoracic and 'one-lung time'), blood loss, transfusion requirements (intraoperative and total), extent of lymphadenectomy (number of lymph nodes sampled), intensive treatment unit (ITU) stay, hospital stay, postoperative morbidity and mortality, pathological stage, grade and survival were recorded. RESULTS: The records of 150 patients were identified for analysis. The cohort was split into five groups, each of 30 patients operated on consecutively. Each of the groups was comparable for age, sex, smoking history, preoperative haemoglobin and creatinine levels, weight loss, American Society of Anesthesiologists' grade, and histological stage and grade of disease. Analysis of the variables pertaining to operation revealed a significant improvement with time including reduced single-lung operating time (P=0.01), reduced blood loss (P=0.03), reduced transfusion requirement (P < 0.0001), reduced ITU stay (P< 0.0001), reduced inpatient stay (P< 0.0001) and an increased yield of lymph nodes (P < 0.0001). CONCLUSION: This study showed a continuing improvement in a surgeon's performance over a 7-year period. With the current trend to shorter training periods there is a case for continuing supervision of the 'fully trained' surgeon within highly specialist units.     

Mean fetal growth curve adjustment]

OBJECTIVE: Three-dimensional models created by milling machines and stereolithography on the basis of 3-dimensional computed tomography scans have become essential in the diagnosis and therapy planning of oral and maxillofacial disorders. The purpose of this study, based on 3 clinical cases, was to examine the advantages of using 3-dimensional computed tomography scans and 3-dimensional milling models of the maxillary sinus before operative sinus elevation and of developing an operative layout with the aid of 3-dimensional models. REPORT DESIGN: Three patients with atrophy of the maxillary alveolar ridge received computed tomography scans before operative sinus elevation with iliac bone transplants and simultaneous dental implantation. These computed tomography data were used to create 3-dimensional graphic and plastic reconstructions of the maxillary sinuses. RESULTS: The 3-dimensional milling models enabled the development of an exact preoperative layout that took into consideration the exact shape of the iliac bone and the selection of dental screw implants. Furthermore, the models offered the possibility of producing an acrylic device for precise implant insertion. Precise planning resulted in good success with implantation 2 years after surgery. CONCLUSION: Three-dimensional diagnosis and treatment layout have become an acknowledge method of operative maxillary sinus floor augmentation combined with simultaneous dental implantation in the upper jaw in difficult cases of sinus lift operations. As far as transplant shape and sinus anatomy are concerned, this has resulted in greater intraoperative precision. A 1-step procedure can thus be performed for augmentation and implantation through use of a well-adapted block transplant and dental screw implants in patients with extensive alveolar ridge atrophy.