乙烯装置脱乙烷塔操作特性的分析

采用ＳＨＢＷＲ方程对某乙烯装置的脱乙烷塔进行了逐板计算，计算结果表明，在工业操作条件下，在该塔的某些段上出现了明显的逆行精馏现象。这不仅大大降低了该塔的分离效率，而且造成操作紊乱。研究结果表明，通过适当地调整该塔的进料位置或增大塔顶回流量可以有效地减小塔内的迎行精馏变化幅度，改善全塔的分离效果，提高操作稳定性。     

Production planning problem with pricing under random yield: CVaR criterion

In this paper, we address a basic production planning problem with price dependent demand and stochastic yield of production. We use price and target quantity as decision variables to lower the risk of low yield. The value of risk control becomes more important especially for products with short life cycle. This is because, the profit implications of low yield might be unbearable in the short run. We apply Conditional Value at Risk （CVaR） to model the, risk. CVaR measure is a coherent risk measure and thereby having nice conceptual and mathematical underpinnings. It is also widely used in practice. We consider the problem under general demand function and general distribution function of yield and find sufficient conditions under which the problem has a unique local maximum. We also both analytically and numerically analyze the impact of parameter change on the optimal solution. Among our results, we analytically show that with increasing risk aversion, the optimal price increases. This relation is opposite to that of in Newsvendor problem where the uncertainty lies in demand side.     

基于ATD-BP神经网络的页岩气产量预测方法

储层改造是页岩气开发的关键步骤,根据储层改造数据进行页岩气井产量预测,对后续施工优化有重要指导意义。然而,储层改造数据与气井产量间呈非线性相关关系,不适用于传统线性预测方法。且储层改造数据存在有效数据较少、噪声数据占比较大、维数较高等问题,不适用于受噪声影响较大的传统BP神经网络非线性预测方法。由此,本文提出一种页岩气储层改造产量预测方法,首先利用自适应阈值去噪(adaptive threshold denoise,ATD)算法去除噪声,再运用BP神经网络对储层改造数据进行非线性拟合,得到页岩气井产量预测模型。实验表明,相比传统的BP神经网络,本文所提方法能够有效提高预测的准确率和稳定性。     

加快现代农业科技推广,保持我国粮食生产持续发展

科学技术进步是保证粮食安全的重要力量,评述了我国农业生态环境存在的主要问题及原因;笔者结合我国实际和前人研究成果,提出了利用科学技术,持续发展粮食生产的对策。     

基于集成EFC/ACD/Petri/Em-plant的生产系统建模与仿真

提出Petri网、实体流图法(EFC)、活动周期法(ACD)集成的生产系统建模方法,并通过Em-plant仿真软件对生产系统进行仿真。以某企业为例,进行了实证研究。结果表明,该方法能有效用于生产系统的建模、仿真与优化。     

Lawsuit

A lawsuit or "suit in law"is a civil action brought in a court of law in which a plaintiff, a party who claims to have incurred loss as a result of a defendant's actions, demands a legal or equitable remedy. The defendant is required to respond to the plaintiff's complaint. If the plaintiff is successful, judgment is in the plaintiff's favor, and a variety of court orders may be issued to enforce a right, award damages, or impose a temporary or permanent injunction to prevent an act or compel an act. A declaratory judgment may be issued to prevent future legal disputes. Although not as common, lawsuit may also refer to a criminal action, criminal proceeding, or criminal claim.     

科技进步——人类智能性自组织过程的序参量

本文基于协同学原理,阐明科技进步是社会经济系统有序状态转向基于原有序状态的新有序状态的过程序参量。通过协同学模型的运行结果说明协同学方法的应用潜力和可能的局限性。指出把协同学观点嵌入传统技术是较好的选择。最后,文中通过几个简单模型分析了科技进步、产业结构、就业结构和社会结构间的关联性。     

Do Newton’s rules of reasoning guarantee truth … must they?

Newton’s Principia introduces four rules of reasoning for natural philosophy. Although useful, there is a concern about whether Newton’s rules guarantee truth. After redirecting the discussion from truth to validity, I show that these rules are valid insofar as they fulfill Goodman’s criteria for inductive rules and Newton’s own methodological program of experimental philosophy; provided that cross-checks are used prior to applications of rule 4 and immediately after applications of rule 2 the following activities are pursued: (1) research addressing observations that systematically deviate from theoretical idealizations and (2) applications of theory that safeguard ongoing research from proceeding down a garden path.     

成组加工中的相似性分析与分组

对机械产品、部件和零件进行相似性分析和分组,是成组技术的核心内容。本文提出了相似性分析必须与分组目标相结合、产品相似性分析和划分成三种类型生产单元的观点。针对目前国内外流行的代码法和工艺流程分析法所存在的问题,提出了将两种方法有机结合起来的综合实用分类成组的方法。     

基于Petri网建模与仿真的制造企业生产系统流程再造方法

对基本Perti网进行了扩充,提出了一种优化Perti网模型,使之能够支持制造企业生产系统流程再造,并提出了一种建立在层次化、模块化和标准化基础上的生产系统建模和仿真方法;运用约束理论的思想,提出了生产系统再造的流程结构优化和瓶颈优化的层次化方法,并探讨了运用时间Petri网模型寻找和消除约束的方法,目的是为制造企业生产系统渐进式流程再造提供有效的方法和工具.这种方法可以将实际系统细化为多个层次的模型,并将生产系统局部作更详细的分析,从而避免了分析整个系统的复杂性.而且,可以通过调整模块和修改模块构造新系统,从而实现生产系统再设计的快速化和柔性化.最后,对这个方法在企业的应用进行了案例分析.