一种新型管式捻股机恒张力放线装置的设计

针对当前工业上使用的小型管式捻股放线张力不恒定问题,对捻股机的放线装置进行研究分析,并设计出一种利用单片机实时控制的新型恒张力放线装置。该装置包含丝杆电机、拉力传感器和以单片机为核心的控制器等。通过该新型管式捻股机放线装置的应用,实现了恒张力放线,稳定了产品质量,保证了安全生产。     

云广±800kV特高压直流线路工程六分裂导线展放

云南至广东±800kV特高压直流线路工程采用六分裂导线,22标段根据现场地形条件分为四个放线区段,其中第二放线区段全部位于高山大岭上,导线展放难度最大,为此我们根据本放线段进行放线准备,如牵张设备、牵引绳、放线滑车等工器具选择,并先行展放较为容易的放线区段,积累经验,为第二放线区段导线展放打下基础,从而使本标段导线展放能够顺利完成。     

Short communication: Prediction of retention pay-off using a machine learning algorithm

Replacement decisions have a major effect on dairy farm profitability. Dynamic programming (DP) has been widely studied to find the optimal replacement policies in dairy cattle. However, DP models are computationally intensive and might not be practical for daily decision making. Hence, the ability of applying machine learning on a prerun DP model to provide fast and accurate predictions of nonlinear and intercorrelated variables makes it an ideal methodology. Milk class (1 to 5), lactation number (1 to 9), month in milk (1 to 20), and month of pregnancy (0 to 9) were used to describe all cows in a herd in a DP model. Twenty-seven scenarios based on all combinations of 3 levels (base, 20% above, and 20% below) of milk production, milk price, and replacement cost were solved with the DP model, resulting in a data set of 122,716 records, each with a calculated retention pay-off (RPO). Then, a machine learning model tree algorithm was used to mimic the evaluated RPO with DP. The correlation coefficient factor was used to observe the concordance of RPO evaluated by DP and RPO predicted by the model tree. The obtained correlation coefficient was 0.991, with a corresponding value of 0.11 for relative absolute error. At least 100 instances were required per model constraint, resulting in 204 total equations (models). When these models were used for binary classification of positive and negative RPO, error rates were 1% false negatives and 9% false positives. Applying this trained model from simulated data for prediction of RPO for 102 actual replacement records from the University of Wisconsin-Madison dairy herd resulted in a 0.994 correlation with 0.10 relative absolute error rate. Overall results showed that model tree has a potential to be used in conjunction with DP to assist farmers in their replacement decisions.     

铜管缠绕机中一种新型光电放卷料筐的速度控制方法

简要介绍铜管缠绕的生产过程，以及缠绕过程速度控制的重要性，提出传统的放卷速度控制存在的问题和产生的原因。重点介绍了用光电开关实现对铜管缠绕机的放卷料筐的速度控制方法。用光电开关组成一套位置信号，用这组信号产生一组离散量取代以往的模拟量检测方法，同时给出了相应的经验数据。这种方法经济、简单，故障率低，控制效果显著。     

新型框式绞线机气动控制系统的研究与应用

介绍了框绞机气动控制系统的功能及原理,以及程序控制,安全保护,比例电磁阀在保证绞合线芯质量上的应用。     

郑东新区某实验学校项目可行性研究

根据郑州市中小学教育资源配置情况调查结果，认为拟建实验学校项目具有现实可行性。详细分析了土地征用、建筑工程和设备投资、办学收入和运营费，最终确定投资回收期为14a，内部收益率约12％。     

Optimal Installation Program for Reprocessing Plants

Abstract

Optimization of the program of installation of reprocessing plants is mathematically formulated as problem of mixed integer programming, which is numerically solved by the branch-and-bound method. A new concept of quasi-penalty is used to obviate the difficulties associated with dual degeneracy. The finiteness of the useful life of the plant is also taken into consideration. It is shown that an analogous formulation is possible for the cases in which the demand forecasts and expected plant lives cannot be predicted with certainty

The scale of the problem is found to have kN binary variables, (k + 2)N continuous variables, and (k + 3)N constraint conditions, where k is the number of intervals used in the piece-wise linear approximation of a nonlinear objective function, and N the overall duration of the period covered by the installation program. Calculations are made for N=24 yr and k = 3, with the assumption that the plant life is 15 yr, the plant scale factor 0.5, and the maximum plant capacity 900 (t/yr). The results are calculated and discussed for four different demand forecasts. The difference of net profit between optimal and non-optimal installation programs is found to be in the range of 50–100 M$. The pay-off matrix is calculated, and the optimal choice of action when the demand cannot be forecast with certainty is determined by applying Bayes' theory. The optimal installation program under such conditions of uncertainty is obtained also with a stochastic mixed integer programming model.     

±660kV直流输电示范工程1000mm2大截面导线张力放线技术

在宁东-山东±660 kV直流输电示范工程晋3标段施工中,通过研究运用2×(一牵二)同步展放1 000mm2大截面导线施工技术,重点阐述了放线机械及施工器具选用、滑车选择及悬挂方式、导引绳及牵引绳展放方法、张牵场选择及布置以及导线同步展放的技术措施,解决了1 000 mm2大截面导线同步展放施工难题.